Stretchable structure of disposable worn article, and underpants-type disposable worn article provided with same

Abstract

[Problem] To improve the cushioning properties of a stretchable structure in a worn state. [Solution] The problem is solved by a structure in which: wavy joint regions 80 following a front-rear direction LD are intermittently arranged in a width direction WD in a stretch area A2; joint parts 81 where a first sheet 12S and a second sheet 12H are fused are provided intermittently in the front-rear direction LD in a portion of each wavy joint region 80 that does not intersect an elastic member 15; a portion intersecting the elastic member 15 is a fixing portion 84 in which the elastic member 15 is fixed to the first sheet 12S and the second sheet 12H; an interval 90W between the adjacent joint parts 81 in the width direction WD is 7-14 mm; a dimension 80W of the joint part 81 in the width direction WD is 0.04-0.3 times the interval 90W; a total amplitude α of a side edge of the wavy joint region 80 is 0.2-0.7 times the interval 90W; and the maximum elongation rate of the stretch area A2 in the width direction WD is 200-240%.

Description

Stretchable structure for disposable wear article and pants-type disposable wear article having the same

[0001] The present invention relates to an expandable structure for a disposable wearing article and a pants-type disposable wearing article having the same.

[0002] BACKGROUND ART Disposable wearing articles such as pants-type disposable diapers, pants-type disposable sanitary napkins, pants-type disposable diaper covers, and tape-type disposable diapers often have an elastic structure that stretches in the width direction in an area including the waist portion to ensure a good fit to the body.

[0003] A typical example of such a stretchable structure includes an elongated elastic member disposed between laminated first and second sheets along the stretch direction. The first and second sheets form a planar stretchable region and serve to cover and conceal the elastic member, while the elastic member embedded between the first and second sheets serves to generate the force required for elastic stretching. When stretched in the stretchable direction, at least portions of the elastic member located at both ends of the stretchable region are fixed to the first and second sheets. In this stretchable structure, the first and second sheets contract in the stretchable direction due to the contractile force of the elastic member, stretching between a natural length state in which pleats (including wrinkled ones; hereinafter simply referred to as pleats) are formed in the first and second sheets, and an expanded state in which the first and second sheets are stretched in the stretchable direction until the pleats disappear as the elastic member stretches (a state stretched to the elastic stretch limit). The first sheet and the second sheet contract together with the elastic member from the elastic extension limit where there are no pleats, and are pleated most densely in the natural length state.

[0004] In such an elastic structure, if the first sheet and the second sheet are free from each other, one sheet may partially or completely float relative to the other sheet, causing unnecessary folds or bulges, so it is desirable that the first sheet and the second sheet are directly or indirectly joined over almost their entire length.

[0005] The joining pattern of the first and second sheets can affect the shape of the pleats, and various joining patterns have been proposed to date. One preferred joining pattern is one in which linear joined regions extending perpendicular to the stretch direction across the elastic members are intermittently arranged in the width direction, with the entire area between adjacent joined regions in the stretch direction being a non-jointed region. In each joined region, the portions that do not intersect with the elastic members have joined regions where the first and second sheets are welded together, positioned so as to closely contact at least both sides of each elastic member in the front-to-rear direction, while the portions that intersect with the elastic members form fixed regions where the elastic members are fixed to the first and second sheets (see Patent Documents 1 to 4). In this case, because rows of joined regions and fixed regions and non-jointed regions are repeatedly formed in the width direction, when the garment is contracted to a certain extent (including the natural length state and the worn state), the portions of the first and second sheets located in the non-jointed regions swell away from each other in opposite directions, forming pleats that extend perpendicular to the stretch direction.

[0006] On the other hand, the stretchable structure in which such pleats are formed has the advantage that it provides a soft feel when in its natural length or when worn, and also has the advantage that when worn, the pleats act as a cushion between the elastic member and the skin, making it less likely that the elastic member will leave marks on the skin due to its tightening.

[0007] However, conventional stretch structures have room for improvement in cushioning properties when worn in a stretched state to some extent.

[0008] JP 2016-067436 A International Publication No. 2018 / 154684 JP 2020-199248 A Japanese Patent No. 6794546 A

[0009] Therefore, a main object of the present invention is to improve the cushioning properties of the stretchable structure when worn.

[0010] The above problem is solved by the following aspects: <First Aspect> A stretchable structure having a first sheet and a second sheet, and a plurality of elongated elastic members extending along a stretchable direction and spaced apart in a direction perpendicular to the stretchable direction between the first and second sheets, wherein the stretchable structure has a stretchable region, wherein wavy-line bonded regions that continue across the elastic members in the orthogonal direction are arranged intermittently in the stretchable direction in the stretchable region, and the entire space between adjacent wavy-line bonded regions in the stretchable direction is a non-bonded region, and portions of each wavy-line bonded region that do not intersect with the elastic members are provided with bonded portions where the first sheet and the second sheet are welded intermittently or continuously in the orthogonal direction, and portions of each wavy-line bonded region that intersect with the elastic members are fixed portions where the elastic members are fixed to the first sheet and the second sheet, the stretchable region is a region that elastically stretches and contracts between a natural length state in which it contracts in the stretch direction due to contraction of the elastic member, and portions of the first sheet and the second sheet located in the non-bonded region expand away from each other in opposite directions, forming pleats continuing in the orthogonal direction, and an expanded state in which it stretches together with the elastic member in the stretch direction to a maximum elongation rate and no pleats remain; the spacing between adjacent joints in the stretch direction is 7 to 14 mm; the dimension of the joints in the stretch direction is 0.04 to 0.3 times the spacing between adjacent joints in the stretch direction; the total amplitude of the side edges of the wavy-line bonded region is 0.2 to 0.7 times the spacing between adjacent joints in the stretch direction; and the maximum elongation rate of the stretchable region in the stretch direction is 200 to 240%.

[0011] (Effects) In a stretchable structure in which the portions of the first and second sheets located in the non-jointed regions swell away from each other in opposite directions, forming orthogonal pleats, the height of the pleats determines cushioning. Therefore, even in a conventional stretchable structure, simply increasing the spacing between the joints without changing the width of the joints can improve cushioning by increasing the pleat height in the natural length state. As a result, cushioning also improves to a certain extent when the garment is stretched to the worn state. However, in a conventional stretchable structure, the pleat height decreases accordingly when the garment is stretched to the worn state. Previously, such a decrease in pleat height when the garment is worn was considered natural, and no room for improvement was considered. While researching various joining patterns, the inventors accidentally discovered a specific combination of conditions that can suppress the decrease in pleat height when the garment is stretched to the worn state. That is, in the stretchable structure of the above embodiment, when the following conditions are met: (a) the bonded regions are wavy, (b) the spacing between adjacent bonded portions in the stretching direction is 7 to 14 mm, (c) the dimension of the bonded portions in the stretching direction is 0.04 to 0.3 times the spacing between adjacent bonded portions in the stretching direction, (d) the total amplitude of the side edges of the wavy bonded regions is 0.2 to 0.7 times the spacing between adjacent bonded portions in the stretching direction, and (e) the maximum elongation rate of the stretchable region in the stretching direction is 200 to 240%, in the natural length state, adjacent bonded portions are not close to each other in the stretching direction, so a certain degree of spacing is maintained, and thin folded folds are formed on one side of the bases or between the bases, with bases on either one or both sides of the spacing in the stretching direction that do not rise enough to form folds. The principle behind this can be explained as follows. That is, when the side edges of the first and second wavy bonded regions adjacent to each other in the deployed state are examined, the side edge of the first wavy bonded region has a proximal peak protruding toward the second wavy bonded region and a distal peak protruding in the opposite direction. Similarly, the side edge of the second wavy bonded region has a proximal peak protruding toward the first wavy bonded region and a distal peak protruding in the opposite direction.As the elastic member contracts, the side edges of the first and second wavy-line bonded regions approach each other in the stretch direction, forming pleats in the first and second sheets. Depending on the position in the perpendicular direction, one of the pleats tends to rise along a line connecting the proximal peaks of the first wavy-line bonded region, the other of the pleats tends to rise along a line connecting the proximal peaks of the second wavy-line bonded region, or both. As a result, thin, folded pleats are formed on one side of or between the bases, with bases on either or both sides of the gap between adjacent bonded regions in the stretch direction that do not rise enough to form pleats. The pleats, viewed from the thickness direction, have a wavy shape along the center of the non-bonded region in the stretch direction. When pleats with such bases are stretched in the stretch direction and worn, the rising positions of the pleats rise and the fold at the boundary between the pleats and the base opens, so there is little reduction in pleat height until this fold opens. Furthermore, the shape of the pleats as viewed from the thickness direction is a wavy line along the center of the stretch direction of the non-bonded region, and the only part perpendicular to the stretch direction is the peak position, so the impact of the pleats collapsing in the thickness direction is not easily transmitted in the direction the pleats continue. This means that the pleats are less likely to collapse. Therefore, with the stretch structure of this embodiment, the reduction in pleat height when worn is suppressed, and the pleats are less likely to collapse, thereby improving cushioning when worn.

[0012] <Second Aspect> The stretchable structure of the disposable wearing article of the first aspect, wherein all of the wavy-line bonding regions have a constant wavelength of the side edges, a constant total amplitude of the side edges that is twice the single amplitude, and an acute-side crossing angle between a center line at which the displacement of the side edges is zero and the orthogonal direction is 3 to 7 degrees.

[0013] (Effects) The wavy bonded regions may be triangular or other wave-like, but a regular, gently curved shape (without straight lines, such as a sinusoidal or arc-shaped shape) is preferable because the bases of the pleats are also regularly formed, resulting in even better cushioning when worn. Furthermore, if the wavy bonded regions are slightly inclined overall relative to the orthogonal direction, as in this embodiment, the pleats are less likely to collapse, resulting in even better cushioning when worn.

[0014] <Third Aspect> The stretchable structure of the disposable wearing article of the first or second aspect, wherein the joints where the first sheet and the second sheet are welded are provided intermittently over the entirety of each of the wavy-line joint regions in the orthogonal direction at intervals shorter than the diameter of the elastic member at its natural length, the joints are in close contact with both sides of each elastic member in the orthogonal direction, and at least one of the first sheet and the second sheet is partly or entirely welded to the elastic member at the fastening portion.

[0015] (Effects) When the bonded portions are intermittently provided at very close intervals throughout the entire wavy bonded region as in this embodiment, hardening due to welding is suppressed, and the texture is uniform throughout each wavy bonded region, making it possible to form wavy pleats with smooth contours. Furthermore, since at least one of the first sheet and the second sheet is partially or entirely welded to the elastic member at the fixing portion, the elastic member can be fixed more strongly than when the elastic member is fixed by friction alone.

[0016] <Fourth Aspect> A pants-type disposable wearing article having an annular waist region formed by joining both side edges of a front body and both side edges of a back body, a middle region extending from the waist region of the front body through a crotch region to the waist region of the back body, a waist opening provided in the waist region on the opposite side to the middle region, and leg openings provided on both sides of the middle region in the width direction, the article comprising: an outer body forming at least the waist region; an inner body attached to the outer body so as to extend from the middle part of the front body in the width direction to the middle part of the back body in the width direction; and side seal regions where both side edges of the outer body on the front body and both side edges of the outer body on the back body are joined together with their inner surfaces facing each other, the outer cover of at least one of the front and back body sections is provided with the stretchable structure of any one of the first to third aspects in a part or all of a region between the side seal regions in the front-to-rear direction, and across the entire width between the side seal regions, with the stretchable structure in the stretchable region stretching in the width direction of the pants-type disposable wearing article.

[0017] (Operation and Effect) The stretchable structure described above is suitable for use as an outer cover for pants-type disposable wearing articles.

[0018] <Fifth Aspect> The pants-type disposable wearing article of the fourth aspect, wherein the outer body of the front body and the outer body of the back body are provided with the stretchable structure of the second aspect in part or all of the area between the side seal areas in the front-to-back direction, so as to cover the entire widthwise area between the side seal areas, and when viewed from the front in a product state in which the inner surfaces of the front body and the back body are in contact with each other and in their natural lengths, a center line of the wavy-line bonded area in the stretchable structure of the outer body of the front body and a center line of the wavy-line bonded area in the stretchable structure of the outer body of the back body are inclined in opposite directions with respect to the orthogonal direction.

[0019] (Effects) As described above, the wavy-line bonded region of the second aspect is particularly preferable. However, when this is applied between the side seal regions of the outer body of a pants-type disposable wearing article, when the inner surfaces of the front and back body are in contact with each other and at their natural lengths as viewed from the front, if the center line of the wavy-line bonded region in the stretch structure of the outer body of the front body and the center line of the wavy-line bonded region in the stretch structure of the outer body of the back body are inclined in the same direction relative to the orthogonal direction (front-to-back direction), the side seal regions of the outer bodies of the front and back bodies will deform into a parallelogram shape inclined in the same direction on either the left or right as the shape of the waist region as viewed from the front will also be similar, resulting in an imbalance in the left-right balance of fit and appearance. In contrast, if the center line of the wavy-line joining region in the stretch structure of the front body exterior and the center line of the wavy-line joining region in the stretch structure of the back body exterior are inclined in opposite directions relative to the orthogonal direction (front-to-back direction) as in this embodiment, when the inner surfaces of the front and back body are in contact with each other and at their natural lengths as a finished product, the deformation between the side seal regions of the front body exterior and the deformation between the side seal regions of the front body exterior will be in opposite directions, and although the inclination of the side seal regions is in opposite directions on the left and right, the shape of the waist region when viewed from the front will be approximately rectangular. This results in a good left-right balance in fit and a good left-right balance in appearance as well, except for the inclination of the side seals.

[0020] According to the present invention, the cushioning properties of the stretchable structure when worn are improved.

[0021] 8 is a plan view showing the inner surface of a pants-type disposable diaper in an unfolded state. 9 is a plan view showing the outer surface of a pants-type disposable diaper in an unfolded state. 10 is a cross-sectional view taken along line 2-2 of FIG. 1. 11 is a cross-sectional view taken along line 3-3 of FIG. 1. (a) A cross-sectional view taken along line 4-4 of FIG. 1, and (b) A cross-sectional view taken along line 5-5 of FIG. 1. 11 is a perspective view of a pants-type disposable diaper. 12 is a plan view showing the outer surface of the inner body in an unfolded state together with the outline of the outer body. 13 is an enlarged plan view showing a main part of the outer body in an unfolded state. 14 is a cross-sectional view taken along line 6-6 of FIG. 1. 15 is a plan view showing an example of the shape of a wavy line bonding region. 16 is a cross-sectional view taken along line 7-7 of FIG. 2, showing (a) a cross-sectional view in a natural length state, (b) a cross-sectional view in a worn state, and (c) a cross-sectional view in an unfolded state. 17 is a cross-sectional view taken along line 7-7 of FIG. 2, showing (a) a cross-sectional view in a natural length state, (b) a cross-sectional view in a worn state, and (c) a cross-sectional view in an unfolded state. 18 is an exploded view of a front outer body and a rear outer body, and (b) a perspective view showing a schematic shape of the front outer body and the rear outer body in their natural length states. (a) is an exploded assembly diagram of the front exterior body and the rear exterior body, (b) is a perspective view showing roughly the shapes of the front exterior body and the rear exterior body in a natural length state. Fig. 15 is an enlarged plan view showing a main part of the exterior body in an unfolded state. Fig. 16 is an enlarged plan view showing a main part of the exterior body in an unfolded state. Fig. 17 is an enlarged plan view showing a main part of the exterior body in an unfolded state. Fig. 18 is an enlarged view of the V part of Fig. 15. Fig. 19 is a cross-sectional view showing the layer structure in the side seal region.

[0022] A pants-type disposable diaper will be described in detail below as an example of a pants-type disposable wearing article, with reference to the accompanying drawings. Adjacent components in the thickness direction are fixed or joined as needed, in addition to the fixed or joined portions described below, in a manner similar to that of known diapers. The dotted patterns in the cross-sectional view indicate adhesives, such as hot-melt adhesives, used as the fixing or joining means. Hot-melt adhesives can be applied by known techniques, such as slot coating, continuous or dotted bead coating, spiral, Z-shaped, or wavy spray coating, or pattern coating (transfer of hot-melt adhesive using a relief printing method). Alternatively or in addition to this, hot-melt adhesive can be applied to the outer periphery of the elastic member to fix the elastic member to an adjacent member. Hot-melt adhesives include, for example, EVA-based, adhesive rubber-based (elastomer-based), polyolefin-based, and polyester / polyamide-based adhesives, but are not limited thereto. Material welding, such as heat sealing or ultrasonic sealing, can also be used as a fixing or joining means for joining the components. In areas where liquid permeability in the thickness direction is required, adjacent components in the thickness direction are fixed or joined in an intermittent pattern. For example, when such intermittent fixing or joining is performed using a hot melt adhesive, intermittent pattern coating such as a spiral, Z-shaped, or wavy pattern can be suitably used. When coating an area greater than the coating width of a single nozzle, intermittent pattern coating such as a spiral, Z-shaped, or wavy pattern can be performed with or without a gap in the width direction. Material welding methods such as heat sealing and ultrasonic sealing can also be used to join the components.

[0023] In addition, as the nonwoven fabric in the following description, known nonwoven fabrics can be used appropriately depending on the location and purpose. The constituent fibers of the nonwoven fabric can be selected without particular limitation, for example, synthetic fibers such as polyolefins (e.g., polyethylene or polypropylene), polyesters, and polyamides (including single-component fibers and core-sheath and other composite fibers), regenerated fibers (e.g., rayon or cupra), and natural fibers (e.g., cotton), and mixtures of these can also be used. In order to increase the flexibility of the nonwoven fabric, it is preferable that the constituent fibers be crimped fibers. Furthermore, the constituent fibers of the nonwoven fabric can be hydrophilic fibers (including fibers made hydrophilic by a hydrophilizing agent), hydrophobic fibers, or water-repellent fibers (including fibers made water-repellent by a water-repellent agent). Furthermore, nonwoven fabrics are generally classified into staple fiber nonwoven fabrics, long fiber nonwoven fabrics, spunbond nonwoven fabrics, meltblown nonwoven fabrics, spunlace nonwoven fabrics, thermal bond (air-through) nonwoven fabrics, needle-punched nonwoven fabrics, point-bond nonwoven fabrics, laminated nonwoven fabrics (including SMS nonwoven fabrics and SMMS nonwoven fabrics in which a meltblown layer is sandwiched between spunbond layers), and the like, depending on the fiber length, sheet formation method, fiber bonding method, and laminated structure, and any of these nonwoven fabrics can be used.

[0024] 1 to 6 show a pants-type disposable diaper. This pants-type disposable diaper includes a rectangular front outer body 12F that forms at least the waist portion of a front body F, a rectangular rear outer body 12B that forms at least the waist portion of a back body B, and an inner body 200 that is provided inside the outer bodies 12F, 12B and extends from the front outer body 12F through the crotch portion to the rear outer body 12B. Both side edges of the front outer body 12F and both side edges of the rear outer body 12B are joined to form side seal regions 12A, so that an opening formed by the front and rear ends of the outer bodies 12F, 12B becomes a waist opening WO through which the wearer's torso passes, and the portions on both widthwise sides of the inner body 200 that are surrounded by the lower edges of the outer bodies 12F, 12B and the side edges of the inner body 200 become leg openings LO through which the legs pass. The inner body 200 is a portion that absorbs and retains excrement such as urine, and the outer bodies 12F, 12B are portions that support the inner body 200 against the wearer's body. Furthermore, the symbol Y indicates the overall length of the diaper in the unfolded state (the length in the front-to-back direction from the edge We of the waist opening WO of the front body F to the edge We of the waist opening WO of the back body B), and the symbol X indicates the overall width of the diaper in the unfolded state.

[0025] This pants-type disposable diaper has an annular waist region T formed by joining both sides of a front body F and both sides of a back body B at side seal regions 12A; a middle region L extending from the waist region T of the front body F through the crotch region to the waist region T of the back body B; a waist opening WO provided in the waist region T on the opposite side of the middle region L; and leg openings LO provided on both sides of the middle region L in the width direction WD. In other words, the waist region T is defined as the area between two imaginary lines extending in the width direction, each passing through the edge of the waist opening WO and the upper ends of the leg openings LO, and the middle region L is defined as the area in the front-to-rear direction LD between the lower end of the side seal regions 12A of the front body F and the lower end of the side seal regions 12A of the back body B. In the unfolded state shown in Figures 1 and 2, both side edges of the middle region L are constricted in a U-shape or curved shape to fit the wearer's legs, giving the diaper a generally hourglass shape overall.

[0026] This pants-type disposable diaper also includes two main assemblies, namely, outer bodies 12F, 12B that form at least the waist region T, and an inner body 200 attached to the outer bodies 12F, 12B so as to extend from the front body F to the back body B. In the side seal region 12A, both side edges of the outer body 12F in the front body F and both side edges of the outer body 12B in the back body B are welded together with their inner surfaces facing each other. The welding can be performed in any suitable pattern. The dimension of the side seal region 12A in the width direction WD can be determined as appropriate. As an example, the dimension of the side seal region 12A in the width direction WD can be 10 to 20 mm.

[0027] (Inner Body) The inner body 200 can have any shape, but is rectangular in the illustrated example. As shown in Figures 3 to 5, the inner body 200 in the illustrated example is an assembly that performs absorption functions by comprising a top sheet 30 that faces the body, a liquid-impermeable sheet 11, and an absorbent element 50 interposed therebetween, but is not limited to this and can be modified as appropriate. Reference numeral 40 denotes an intermediate sheet (second sheet) that is provided between the top sheet 30 and the absorbent element 50 in order to quickly transfer liquid that has permeated the top sheet 30 to the absorbent element 50, and reference numeral 60 denotes rising gathers 60 that extend from both sides of the inner body 200 so as to contact the wearer's legs in order to prevent excrement from leaking out the sides of the inner body 200.

[0028] (Top sheet) The top sheet 30 is liquid-permeable, and examples thereof include a perforated or non-perforated nonwoven fabric, a perforated plastic sheet, etc. The top sheet 30 may consist of a single sheet, or a laminated sheet obtained by bonding two or more sheets together. Similarly, the top sheet 30 may consist of a single sheet, or two or more sheets in the planar direction.

[0029] The side edges of the top sheet 30 may be folded back at the side edges of the absorbent element 50, or may not be folded back and may extend out to the sides beyond the side edges of the absorbent element 50.

[0030] The top sheet 30 is preferably fixed to an adjacent backside member by a material welding joining means such as heat sealing or ultrasonic sealing, or by a hot melt adhesive, in order to prevent misalignment relative to the backside member, etc. In the illustrated example, the top sheet 30 is fixed to the surface of the intermediate sheet 40 and the surface of the portion of the packaging sheet 58 that is located on the front side of the absorbent body 56 by a hot melt adhesive applied to the backside of the top sheet 30.

[0031] (Intermediate Sheet) In order to quickly transfer liquid that has permeated the top sheet 30 to the absorbent body 56 and to prevent the absorbed liquid from "flowing back" from the absorbent body 56, an intermediate sheet (also called a "second sheet") 40 that has a faster liquid permeation rate than the top sheet 30 can be provided. The intermediate sheet 40 can also be omitted.

[0032] Examples of the intermediate sheet 40 include the same material as the top sheet 30, spunlace nonwoven fabric, spunbond nonwoven fabric, SMS nonwoven fabric, pulp nonwoven fabric, a mixed sheet of pulp and rayon, point-bond nonwoven fabric, and crepe paper. Air-through nonwoven fabric is particularly preferred because of its bulkiness. For the air-through nonwoven fabric, it is preferable to use composite fibers with a core-sheath structure, and in this case, the resin used for the core may be polypropylene (PP), but polyester (PET) with high rigidity is preferred. The basis weight is 17 to 80 g / m ２ is preferred, and 17 to 50 g / m ２ The thickness of the raw material fibers of the nonwoven fabric is preferably 2.0 to 10 dtex. In order to make the nonwoven fabric bulky, it is also preferable to use eccentric fibers, hollow fibers, or eccentric and hollow fibers as all or part of the raw material fibers.

[0033] In the illustrated example, the intermediate sheet 40 is positioned in the center and is shorter than the width of the absorbent body 56, but it may be provided across the entire width. The length of the intermediate sheet 40 in the front-to-rear direction may be the same as the entire length of the diaper, the same as the length of the absorbent element 50, or within a short length range centered on the liquid-receiving region.

[0034] In order to prevent the intermediate sheet 40 from shifting relative to the backside member, it is desirable to fix the intermediate sheet 40 to the backside adjacent member by a joining means that uses material welding such as heat sealing or ultrasonic sealing, or by a hot melt adhesive. In the illustrated example, the intermediate sheet 40 is fixed to the surface of the portion of the packaging sheet 58 that is located on the front side of the absorbent body 56 by a hot melt adhesive applied to the backside of the intermediate sheet 40.

[0035] (Liquid-impermeable sheet) The material of the liquid-impermeable sheet 11 is not particularly limited, but examples thereof include a plastic film made of a polyolefin resin such as polyethylene or polypropylene, a laminated nonwoven fabric in which a plastic film is provided on the surface of a nonwoven fabric, and a laminated sheet in which a nonwoven fabric or the like is overlaid and bonded to a plastic film. It is preferable to use a liquid-impermeable and moisture-permeable material for the liquid-impermeable sheet 11, which is preferred from the viewpoint of preventing stuffiness. As a moisture-permeable plastic film, a microporous plastic film obtained by kneading an inorganic filler into a polyolefin resin such as polyethylene or polypropylene, forming a sheet, and then stretching it uniaxially or biaxially is widely used. In addition, nonwoven fabrics using microdenier fibers, nonwoven fabrics whose leak-proofing properties have been enhanced by reducing the voids in the fibers through the application of heat or pressure, and sheets that have been made liquid-impermeable without using a plastic film by methods such as coating with a highly absorbent resin or a hydrophobic resin or a water-repellent agent can also be used as the liquid-impermeable sheet 11, but it is preferable to use a resin film in order to obtain sufficient adhesive strength when bonding with the cover nonwoven fabric 13 described below via a hot melt adhesive.

[0036] The liquid-impermeable sheet 11 is made to have a width that fits behind the absorbent element 50 as shown in the figure, and in order to improve leakproofness, it can also be made to wrap around both sides of the absorbent element 50 and extend to both sides of the absorbent element 50 on the side of the top sheet 30. The appropriate width of this extension is about 5 to 20 mm on each side.

[0037] (Rising gathers) The rising gathers 60 extend along both side portions of the inner body 200 over the entire length in the front-to-rear direction LD, and are provided to come into contact with the wearer's legs to prevent side leakage. If necessary, the rising gathers 60 can be omitted.

[0038] 1, 3, and 4 stand up from the side of the inner body 200 to the front side. These stand-up gathers 60 have a base side portion 60B that stands up obliquely toward the widthwise center, and a tip side portion 60A that stands up obliquely from the middle toward the widthwise outer side, but are not limited to this and can be modified as appropriate, such as a form in which the entire gathers stand up toward the widthwise center.

[0039] Explaining in more detail, the rising gathers 60 in the illustrated example are formed by folding back a strip-shaped gathered nonwoven fabric 62 having a length equal to the longitudinal length of the inner body 200 in the width direction WD at its tip portion and folding it in half, and fixing a plurality of elongated gathered elastic members 63 at intervals in the width direction WD between the folded-back portion and the sheet in the vicinity thereof in a stretched state along the longitudinal direction. The base end of the rising gathers 60 located opposite the tip portion (the end opposite the folded-back portion of the sheet in the width direction WD) forms a root portion 65 fixed to the side portion of the inner body 200 on the back side of the liquid-impermeable sheet 11, and the portion other than this root portion 65 forms a main body portion 66 (the portion on the folded-back portion side) extending from the root portion 65. The main body portion 66 also has a root portion 60B extending toward the center in the width direction, and a tip portion 60A that is folded back at the tip of the root portion 60B and extends outward in the width direction. This configuration is a surface-contact type of rising gather 60, but it is also possible to employ a line-contact type of rising gather 60 that is not folded back outward in the width direction. Furthermore, both front-to-rear end portions of the main body portion 66 serve as fallen portions 67 that are fixed in a fallen state to the side surfaces of the topsheet 30, while the front-to-rear intermediate portion between these serves as an unfixed free portion 68, and gathered elastic members 63 that extend along the front-to-rear direction LD are fixed in a stretched state to at least the tip portions of these free portions 68.

[0040] In the rising gathers 60 configured as described above, the contractile force of the gather elastic members 63 acts to bring the front-rear end portions closer together, but while the front-rear end portions of the main body portion 66 are fixed so as not to stand up, the portion between them is an unfixed free portion 68, and therefore only the free portion 68 stands up so as to abut against the body as shown by the arrow in Fig. 3. In particular, when the base portion 65 is located on the back side of the inner body 200, the free portion 68 stands up so as to open outward in the width direction in the crotch region and its vicinity, and the rising gathers 60 come into surface contact with the leg circumference, improving fit.

[0041] In a bent form, such as the illustrated example of the rising gathers 60, in which the main body portion 66 is composed of a root portion 60B extending toward the center in the width direction and a tip portion 60A folded back at the tip of the root portion 60B and extending outward in the width direction, the tip portion 60A and the root portion 60B are joined in a collapsed state at the collapsed portion 67, and the root portion 60B is joined in a collapsed state to the topsheet 30. To join the opposing surfaces of the collapsed portion 67, at least one of various application methods of hot melt adhesive and material welding such as heat sealing and ultrasonic sealing can be used. In this case, the joining of the root portion 60B and the topsheet 30 and the joining of the tip portion 60A and the root portion 60B may be performed by the same means or by different means. For example, one preferred embodiment is to join the root portion 60B and the top sheet 30 with a hot melt adhesive, and to join the tip portion 60A and the root portion 60B with material welding.

[0042] As the gathered nonwoven fabric 62, a nonwoven fabric that is soft and has excellent uniformity and hiding properties, such as a spunbond nonwoven fabric (SS, SSS, etc.), an SMS nonwoven fabric (SMS, SSMMS, etc.), or a meltblown nonwoven fabric, and that has been subjected to a water-repellent treatment with silicone or the like as necessary, can be suitably used, and the fiber basis weight is 10 to 30 g / m ２It is preferable that the thickness of the gathered elastic member 63 be about 470 to 1240 dtex. For the gathered elastic member 63, rubber thread or the like can be used. When spandex rubber thread is used, the thickness is preferably 470 to 1240 dtex, more preferably 620 to 940 dtex. The elongation percentage at the time of fixing is preferably 150 to 350%, more preferably 200 to 300%. As shown in the figure, a waterproof film 64 can be interposed between the two folded gathered nonwoven fabrics 62. In this case, the gathered nonwoven fabric 62 can be partially omitted where the waterproof film 64 is present. However, in order to achieve a cloth-like appearance and feel of the product, it is necessary that at least the outer surface of the rising gathers 60 from the base end to the tip end be formed of the gathered nonwoven fabric 62, as in the illustrated example.

[0043] The number of gathered elastic members 63 provided in the free portion of the rising gathers 60 is preferably 2 to 6, and more preferably 3 to 5. The appropriate spacing is 3 to 10 mm. With this configuration, the gathered elastic members 63 can easily contact the skin over the entire area where they are arranged. Gathered elastic members 63 may be arranged not only on the tip side but also on the base side.

[0044] In the free portion 68 of the rising gathers 60, at least one of various application methods of hot melt adhesive and material welding, such as heat sealing or ultrasonic sealing, can be used to bond the inner and outer layers of the gathered nonwoven fabric 62 together and to secure the gathered elastic member 63 sandwiched therebetween. Bonding the entire surfaces of the inner and outer layers of the gathered nonwoven fabric 62 reduces flexibility, so it is preferable to leave the areas other than the adhesive joints of the gathered elastic member 63 unbonded or to only weakly bond them. In the illustrated example, hot melt adhesive is applied only to the outer peripheral surface of the gathered elastic member 63 using an application means such as a comb gun or a SureWrap nozzle, and the gathered elastic member 63 is sandwiched between the inner and outer layers of the gathered nonwoven fabric 62. This structure allows the hot melt adhesive applied only to the outer peripheral surface of the gathered elastic member 63 to secure the gathered elastic member 63 to the inner and outer layers of the gathered nonwoven fabric 62 and to secure the inner and outer layers of the gathered nonwoven fabric 62 together.

[0045] Similarly, the waterproof film 64 incorporated into the rising gathers 60 can be fixed to the gathered nonwoven fabric 62, and the fallen portion 67 can be fixed using at least one of various application methods of hot melt adhesive and material welding such as heat sealing or ultrasonic sealing.

[0046] (Absorbent Element) The absorbent element 50 has an absorbent body 56 and a wrapping sheet 58 that wraps the entire absorbent body 56. The wrapping sheet 58 may be omitted.

[0047] (Absorbent body) The absorbent body 56 can be formed from a fiber assembly. This fiber assembly can be made by stacking staple fibers such as cotton-like pulp or synthetic fibers, or a filament assembly obtained by opening a tow (fiber bundle) of synthetic fibers such as cellulose acetate as needed. When cotton-like pulp or staple fibers are stacked, the fiber weight can be, for example, 100 to 300 g / m ２ In the case of a filament aggregate, for example, 30 to 120 g / m ２ The fineness of the synthetic fibers is, for example, 1 to 16 dtex, preferably 1 to 10 dtex, and more preferably 1 to 5 dtex. In the case of a filament aggregate, the filaments may be non-crimped fibers, but are preferably crimped fibers. It is preferable that highly absorbent polymer particles are dispersed and held within the absorbent body 56.

[0048] The absorbent body 56 may be rectangular in shape, but as shown in Figure 7, etc., if it has an hourglass shape with a narrower constricted portion 56N in the middle in the front-to-rear direction than the front and rear sides, it is preferable because this improves the fit of the absorbent body 56 itself and the rising gathers 60 around the legs.

[0049] The dimensions of the absorber 56 can be determined as appropriate as long as it extends to the front, rear, left, and right of the urination opening position, but it is preferable that it extends to or near the peripheral edge of the inner body 200 in the front-to-rear direction LD and the width direction WD.

[0050] (Superabsorbent polymer particles) The absorbent body 56 may contain superabsorbent polymer particles in part or in its entirety. Superabsorbent polymer particles include not only "particles" but also "powder." As the superabsorbent polymer particles, those used in this type of disposable diaper can be used as they are. For example, when sieved using a 500 μm standard sieve (JIS Z8801-1:2006) (shaking for 5 minutes), the percentage of particles remaining on the sieve is preferably 30% by weight or less, and when sieved using a 180 μm standard sieve (JIS Z8801-1:2006) (shaking for 5 minutes), the percentage of particles remaining on the sieve is preferably 60% by weight or more.

[0051] The material for the superabsorbent polymer particles is not particularly limited, but one with a water absorption capacity of 40 g / g or more is preferred. Examples of superabsorbent polymer particles include starch-based, cellulose-based, and synthetic polymer-based materials, and examples that can be used include starch-acrylic acid (salt) graft copolymers, saponified starch-acrylonitrile copolymers, crosslinked products of sodium carboxymethylcellulose, and acrylic acid (salt) polymers. The shape of the superabsorbent polymer particles is preferably a commonly used powder-like shape, but other shapes can also be used.

[0052] The basis weight of the highly absorbent polymer particles can be determined appropriately depending on the absorption amount required for the application of the absorbent body 56. Therefore, although it cannot be generally stated, it is generally in the range of 50 to 350 g / m ２ It can be said that:

[0053] (Packaging Sheet) When using a packaging sheet 58, tissue paper, particularly crepe paper, nonwoven fabric, polylaminated nonwoven fabric, perforated sheet, etc. can be used as the material. However, it is desirable that the sheet is one from which the superabsorbent polymer particles do not escape. When using nonwoven fabric instead of crepe paper, hydrophilic SMS nonwoven fabric (SMS, SSMMS, etc.) is particularly suitable, and polypropylene, polyethylene / polypropylene composite material, etc. can be used as the material. The basis weight is 5 to 40 g / m ２ , especially 10 to 30 g / m ２ It is preferable that:

[0054] The packaging form of the packaging sheet 58 can be determined as appropriate, but from the standpoint of ease of manufacturing and preventing leakage of superabsorbent polymer particles from the front and rear edges, it is preferable to wrap it around the absorbent body 56 in a cylindrical shape so as to surround the front, back, and both side surfaces, with the front and rear edges extending beyond the front and rear of the absorbent body 56, and to join the overlapping wound parts and the overlapping parts of the extending front and rear edges by a joining means such as a hot melt adhesive or material welding.

[0055] (Cover nonwoven fabric) In a pants-type disposable diaper with a two-part exterior, the inner body 200 is exposed between the front outer body 12F and the rear outer body 12B. Therefore, in order to prevent the liquid-impermeable sheet 11 from being exposed on the back surface of the inner body 200, it is preferable to provide a cover nonwoven fabric 13 that covers the back surface of the inner body 200, extending from between the front outer body 12F and the inner body 200 to between the rear outer body 12B and the inner body 200.

[0056] The cover nonwoven fabric 13 is not particularly limited by the type of fiber or the method of bonding (entangling) the fibers, and may be selected appropriately from, for example, the same materials as the first and second sheets of the exterior bodies 12F and 12B described below. As an example of the cover nonwoven fabric 13, an air-through nonwoven fabric can be suitably used, and in this case, the basis weight is 20 to 40 g / m ２ The thickness is preferably 0.3 to 1.0 mm. The cover nonwoven fabric 13 may be a non-porous nonwoven fabric that does not have holes that penetrate from the front to the back, or a porous nonwoven fabric that has a large number of holes that penetrate from the front to the back at intervals.

[0057] The front-rear direction range of the cover nonwoven fabric 13 is not particularly limited, and may extend in the front-rear direction LD over the entire area from the front end to the rear end of the inner body 200 as shown in Figures 2 and 5, or may extend in the front-rear direction LD from the front-rear direction central position of the area where the front outer body 12F and the inner body 200 overlap to the front-rear direction central position of the area where the rear outer body 12B and the inner body 200 overlap as shown in Figure 7. In the example shown in Figure 7, the front-rear direction length 13y of the overlapping portion between the cover nonwoven fabric 13 and the front outer body 12F and the front-rear direction length 13y of the overlapping portion between the cover nonwoven fabric 13 and the rear outer body 12B can be determined as appropriate.

[0058] The widthwise range of the cover nonwoven fabric 13 is set to a range that can hide the exposed back surface of the liquid-impermeable sheet 11. For this reason, in the illustrated example, the liquid-impermeable sheet 11 is exposed between the base ends of the left and right rising gathers 60, and therefore the cover nonwoven fabric 13 is provided so as to cover the widthwise range from the back side of the base end of at least one of the rising gathers 60 to the back side of the base end of the other rising gather 60. This allows the liquid-impermeable sheet 11 to be concealed by the cover nonwoven fabric 13 and the gathered nonwoven fabric 62 of the rising gathers 60. Furthermore, even if the widthwise end ends of the cover nonwoven fabric 13 do not cover the back sides of the base ends of the rising gathers 60, but the gathered nonwoven fabric 62 covers the back sides of the widthwise end ends of the cover nonwoven fabric 13, it is still possible to conceal the liquid-impermeable sheet 11 by the cover nonwoven fabric 13 and the gathered nonwoven fabric 62. In this case, since both side edges of the cover nonwoven fabric 13 are covered with the gathered nonwoven fabric 62 , there is an advantage that both side edges of the cover nonwoven fabric 13 are less likely to peel off from the liquid-impermeable sheet 11 .

[0059] The inner and outer surfaces of the cover nonwoven fabric 13 can be bonded to their opposing surfaces with a hot melt adhesive. The fixed area of ​​the cover nonwoven fabric 13 can be the entire front-to-back direction and the entire width direction of the cover nonwoven fabric 13, or a portion can be left unfixed. For example, if both widthwise ends of the cover nonwoven fabric 13 are unfixed, the cover nonwoven fabric 13 is less likely to be affected even if the sides of the absorbent body 56 shrink somewhat due to the influence of the rising gathers 60, which has the advantage of making the cover nonwoven fabric 13 less likely to wrinkle or fold.

[0060] (Inner body fastening parts) The inner body 200 can be fastened to the outer bodies 12F, 12B by a joining means that uses material welding, such as heat sealing or ultrasonic sealing, or by a hot melt adhesive. In the illustrated example, the inner body 200 is fastened to the inner surfaces of the outer bodies 12F, 12B via hot melt adhesive applied to the back surface of the inner body 200, that is, in this case, the back surface of the liquid-impermeable sheet 11 and the base portions 65 of the rising gathers 60. The inner body fastening parts 201, 202 that fasten the inner body 200 to the outer bodies 12F, 12B can be provided over almost the entire overlapping area, as shown in Figure 2, and can also be provided in areas excluding both widthwise ends of the inner body 200, for example.

[0061] (Outer Body) The outer bodies 12F, 12B in the illustrated example are composed of a rectangular front outer body 12F that forms the waist region T of the front body F and a rectangular back outer body 12B that forms the waist region T of the back body B, and the front outer body 12F and the rear outer body 12B are not continuous on the crotch side but are spaced apart in the front-to-back direction LD. This separation distance 12d can be, for example, about 0.2 to 0.5 times the total length Y. The outer bodies 12F, 12B may also be integral and continuous from the front body F to the back body B through the crotch area.

[0062] The portion of the outer body 12F, 12B located in the waist region T can be divided into a waist portion W forming the end on the waist opening WO side and a lower waist portion U below this. If the portion of the outer body 12F, 12B located in the waist region T has a boundary where the stretchability in the width direction WD changes (for example, where the thickness or elongation rate of the elastic member changes), the waist portion W is the portion closer to the waist opening WO than the boundary located closest to the waist opening WO (if there is a gap between the lowermost elastic member of the waist portion W and the uppermost elastic member of the lower waist portion U, the center of that gap is the boundary). If there is no such boundary, the waist portion W is the waist extension portion 12E extending further toward the waist opening WO than the absorbent body 56 or the inner body 200. The length of these portions in the front-to-rear direction LD varies depending on the size of the product and can be determined as appropriate. As an example, the waist portion W can be 15 to 40 mm, and the lower waist portion U can be 65 to 120 mm.

[0063] In the illustrated example, the front exterior body 12F and the rear exterior body 12B have the same dimension in the front-to-rear direction LD and neither has a portion located in the middle region L, but as shown by the two-dot chain line in Fig. 7, the rear exterior body 12B has a longer dimension in the front-to-rear direction than the front exterior body 12F, and the front exterior body 12F does not have a portion located in the middle region L, but the rear exterior body 12B may have a buttocks covering portion C extending from the waist region T toward the middle region L. Although not shown, the front exterior body 12F may also be provided with a groin covering portion extending from the waist region T toward the middle region L, or a configuration may be adopted in which a groin covering portion is provided but a buttocks covering portion is not provided.

[0064] The exterior bodies 12F, 12B incorporate elastic members 15, 17 to improve fit around the wearer's waist, and form stretchable regions A2 that elastically stretch in the width direction WD together with the elastic members 15, 17. The stretchable regions A2 allow the exterior bodies 12F, 12B to stretch between a natural length state in which the elastic members 15, 17 contract in the width direction WD to form pleats P, and an expanded state in which the elastic members 15, 17 stretch to their maximum elongation rate to remove the pleats P. The elastic members 15, 17 may be any known elongated elastic member, such as a thread or strip, without any particular limitation. The elastic members 15, 17 may be made of synthetic or natural rubber.

[0065] To explain the elastic members 15, 17 in the illustrated example in more detail, a plurality of waist elastic members 17 made of elongated elastic members are attached to the waist portion W of the outer bodies 12F, 12B at intervals in the front-to-rear direction so as to be continuous across the entire width direction WD. Furthermore, one or more of the waist elastic members 17 arranged in the region adjacent to the lower waist portion U may overlap the inner body 200, or may be provided on both sides in the width direction except for the central portion in the width direction that overlaps with the inner body 200. The waist elastic members 17 should have a thickness of 155 to 1880 dtex, particularly 470 to 1240 dtex (in the case of synthetic rubber; in the case of natural rubber, a cross-sectional area of ​​0.05 to 1.5 mm). ２ , especially 0.1 to 1.0 mm ２It is preferable to provide about 2 to 15, and especially about 4 to 10, rubber threads (approximately 170 mm long) at intervals of 2 to 12 mm, especially 3 to 7 mm. The maximum elongation rate in the width direction WD of the waist portion W provided by the waist elastic members 17 can be appropriately determined, and can be, for example, about 150 to 400%, especially about 220 to 320%. The spacing between the waist elastic members 17 in the front-to-back direction LD may be constant or may vary midway along the front-to-back direction LD.

[0066] It is also preferable that a plurality of waist lower elastic members 15 made of elongated elastic material are attached at intervals in the front-to-rear direction to the waist lower portion U of the outer bodies 12F, 12B. The waist lower elastic members 15 should have a thickness of 155 to 1880 dtex, particularly 470 to 1240 dtex (in the case of synthetic rubber; in the case of natural rubber, a cross-sectional area of ​​0.05 to 1.5 mm ２ , especially 0.1 to 1.0 mm ２ It is preferable to provide about 5 to 30 rubber threads (approximately 1 / 4" thick) spaced at intervals of 1 to 15 mm, particularly 3 to 8 mm. The maximum elongation in the width direction WD of the lower waist portion U provided by the lower waist elastic members 15 can be determined as appropriate, and can be, for example, about 180 to 300%, more preferably 190 to 240%, and particularly preferably 200 to 240%. The spacing between the lower waist elastic members 15 in the front-to-back direction LD may be constant, or may vary midway in the front-to-back direction LD as in the illustrated example.

[0067] When the lower waist elastic member 15 is provided within the range of the absorbent body 56 in the front-to-back direction LD, as in the lower waist portion U in the illustrated example, in order to prevent contraction of the absorbent body 56 in the width direction WD in part or all of the region, it is preferable to designate the widthwise center (preferably including the entire inner body fastening portions 201, 202) including part or all of the overlapping portion with the absorbent body 56 in the width direction WD as a non-elastic region A1, and designate both sides of the non-elastic region A2 in the width direction. The maximum elongation rate of the non-elastic region A1 can be determined as appropriate, for example, approximately 100-120%. The lower waist portion U can also be designated as a stretchable region A2 throughout the entire width direction WD. While the waist portion W is preferably designated as a stretchable region A2 throughout the entire width direction WD, a non-elastic region A1 may also be provided in the widthwise center, as in the lower waist portion U.

[0068] The stretchable region A2 and non-stretchable region A1 can be achieved by, during the manufacture of the outer garments 12F, 12B, fixing the elastic member 15 and then cutting the lower-waist elastic member 15 in the region that will become the non-stretchable region A1 by applying pressure and heat to the region that will become the non-stretchable region A1, either at a single location in the middle of the width direction or by cutting it into multiple small locations, thereby retaining stretchability in the stretchable region A2 while eliminating stretchability in the non-stretchable region A1. In these cases, cut pieces 16 of the elastic member that do not substantially contribute to stretching remain in the outer garments 12F, 12B. In the stretchable region A2, the elastic members 15, 17 are continuous across the entire width (stretch direction).

[0069] 5, the waist portion W has an outer portion 18 formed by laminating a first sheet 12S made of nonwoven fabric and a second sheet 12H made of nonwoven fabric, and an inner portion 19 formed by folding the first sheet 12S and the second sheet 12H continuing from the outer portion 18 inward at the edge We of the waist opening WO, with the first sheet 12S extending across the entire waist portion W, and the inner portion 19 is joined to the outer portion 18 by a hot melt adhesive HM (or by welding). In the illustrated example, the first sheet 12S and the second sheet 12H of the outer portion 18 extend from the waist portion W to the lower waist portion U (over the entire torso region T in the illustrated example), but this is not limited thereto and appropriate modifications are possible, such as forming the lower waist portion U from a different sheet. In the illustrated example, the second sheet 12H of the inner portion 19 extends only to the middle of the waist portion W in the front-to-back direction LD, and the first sheet 12S extends from the waist portion W to the lower waist portion U and covers the end of the inner body 200 on the waist opening WO side, but this is not limited to this. For example, both the first sheet 12S and the second sheet 12H may extend to the lower waist portion U, or both the first sheet 12S and the second sheet 12H may be contained within the waist portion W, or may extend only as far as the waist opening WO side of the inner body 200 and not cover the end of the inner body 200. Furthermore, the second sheet 12H may be present only in the outer portion 18 and not extend to the inner portion 19. Furthermore, unlike the illustrated example, the inner portion 19 may not be provided.

[0070] The material of the first sheet 12S and the second sheet 12H can be determined as appropriate, but a breathable sheet such as a nonwoven fabric can be suitably used. For example, the first sheet 12S and the second sheet 12H can be made of a nonwoven fabric made of synthetic fibers such as polyolefins (e.g., polyethylene and polypropylene), polyesters, and polyamides, or a mixed fiber or composite fiber made of two or more of these. Examples of fiber bonding methods include the air-through method and the point bond method. The fineness, basis weight, and thickness of the nonwoven fabric used for the first sheet 12S and the second sheet 12H can be determined as appropriate. As an example, the first sheet 12S and the second sheet 12H can have a fineness of 1.0 to 3.0 dtex and a basis weight of 10 to 20 g / m. ２ In addition to long fiber nonwoven fabrics with a thickness of 0.15 to 0.50 mm, ２ A short fiber nonwoven fabric having a thickness of 0.7 to 1.5 mm can be used.

[0071] In the example shown in Figure 5, waist elastic members 17 are provided between the outer and inner portions 18 and 19 of the waist region W to form the stretchable region A2, but this is not limited thereto. Although not shown, the waist elastic members 17 may be provided between the first and second sheets 12S and 12H of the inner portion 19, or between the first and second sheets 12S and 12H of the outer portion 18. In the example shown in Figure 5, the waist elastic members 17 are secured to the outer and second sheets 12H of the inner portion 19 with hot melt adhesive HM applied to their outer surfaces, but they may also be secured with fastening portions 84, which will be described later. When the waist region W is at its natural length, it contracts in the width direction WD together with the waist elastic members 17, forming pleats. However, when the waist region W is stretched to a certain extent in the width direction WD together with the waist elastic members 17 and worn, the pleats expand, and when unfolded, the pleats disappear completely.

[0072] In the lower waist portion U, a stretchable region A2 is formed by providing lower waist elastic members 15 between the first sheet 12S and the second sheet 12H in the outer portion 18, but this is not limiting. Although not shown, some or all of the lower waist elastic members 15 may be provided between other sheets. In the illustrated example, the lower waist elastic members 15 are secured to the first sheet 12S and the second sheet 12H by welding at the wavy-line bonding region 80 (described below). However, this is not limiting, and some or all of the lower waist elastic members 15 may be secured to the first sheet 12S and the second sheet 12H with hot melt adhesive HM applied to the outer surface of the lower waist elastic members 15. To secure the elastic members for forming the stretchable region A2, such as the lower waist elastic members 15, between the first sheet 12S and the second sheet 12H, the first sheet 12S and the second sheet 12H may be continuous over at least the entire stretchable region A2, and preferably over the entire elastic member-containing region.

[0073] In the illustrated exterior bodies 12F, 12B, wavy-line bonded regions 80 extending in the front-to-back direction LD across the elastic members 15, 17 are spaced apart in the width direction WD, and the entire space between adjacent wavy-line bonded regions 80 in the width direction WD is a non-bonded region 90 (i.e., the wavy-line bonded regions 80 and the non-bonded regions 90 alternate in the width direction). In the illustrated example, the wavy-line bonded regions 80 and the non-bonded regions 90 extend over almost the entire overlapping portion of the first sheet 12S and the second sheet 12H (i.e., across the outer portion 18 and the inner portion 19). However, they may be provided only in a portion of the overlapping portion, such as only in the outer portion 18 or only in a lower-waist portion U of the outer portion 18. Furthermore, in the illustrated exterior bodies 12F, 12B, the wavy-line bonded regions 80 and the non-bonded regions 90 extend over the entire overlapping portion, including the stretched region A2 and the non-stretched region A1. However, the wavy-line bonded regions 80 and the non-bonded regions 90 may not be provided in the non-stretched region A1, for example. Furthermore, as shown in the illustrated example, if one of the first sheet 12S and the second sheet 12H of the inner portion 19 extends further toward the center in the front-to-back direction LD than the other sheet, the extending portion may have traces similar to the bonding portion 81 described below for forming the wavy bonding area 80, or may have no traces at all.

[0074] In each wavy-line bonding region 80, a bonding portion 81 where the first sheet 12S and the second sheet 12H are welded is provided intermittently or continuously in a portion that does not intersect with the elastic member 15, and a fixing portion 84 where the elastic member 15 is fixed to the first sheet 12S and the second sheet 12H. Ultrasonic welding is a suitable welding-bonding method for forming the bonding portion 81, but heat welding by heating a roll can also be used. Here, the state in which the first sheet 12S and the second sheet 12H are welded and joined includes not only a state in which almost all of the fibers of the first sheet 12S and the second sheet 12H have melted and become one (for example, fewer than 10 fibers may protrude) and formed into a film-like shape (which is more transparent than the surrounding area), but also a state in which almost all of the fibers of the layer on the joining surface side of both the first sheet 12S and the second sheet 12H are welded together, while the fibers of the layer on the opposite surface side remain independent and not welded, or a state in which almost all of the fibers of either the first sheet 12S or the second sheet 12H have melted and formed into a film-like shape, while almost all of the fibers of the other sheet or the fibers of the layer on the opposite side of the joining surface remain unmelted, and all other states in which the first sheet 12S and the second sheet 12H are joined.

[0075] 11(a) or 12(a), the stretchable region A2 having intermittent wavy-line bonded regions 80 in the width direction WD (stretching direction) contracts in the width direction WD due to contraction of the elastic members 15, and the portions of the first sheet 12S and the second sheet 12H located in the non-bonded regions 90 expand in opposite directions away from each other, forming pleats P continuing in the front-to-back direction LD (orthogonal direction), forming a natural length state, and as shown in FIG. 11(c) or 12(c), the stretchable region A2 stretches in the width direction WD together with the elastic members 15 to the maximum elongation rate, eliminating the pleats P. Note that FIGS. 11(b) and 12(b) show the stretched state at a stretch rate of 150% in the width direction WD, which is assumed when the garment is worn.

[0076] The dimensions of each part can be determined as appropriate. For example, the widthwise WD spacing 90W of the bonded portions 81 of adjacent wavy-line bonded regions 80 (equal to the widthwise WD dimension 90W of the non-bonded region 90) is 7 to 14 mm, particularly 8 to 11 mm. The widthwise WD dimension 80W of the bonded portions 81 is preferably 0.04 to 0.3 times, particularly 0.07 to 0.15 times (or 0.49 to 2.8 mm, particularly 0.8 to 1.65 mm) the spacing between adjacent bonded portions 81 in the width direction WD, since this ensures a large width for the portions that become the folds P. In this case, it is particularly preferable that the total amplitude α of the side edges of the wavy-line bonded regions 80 is 0.2 to 0.7 times, particularly 0.3 to 0.6 times the spacing between adjacent bonded portions 81 in the width direction WD, and that the maximum elongation of the stretchable region A2 in the width direction WD is 200 to 240%, particularly 200 to 220%. That is, in an elastic structure in which the portions of the first sheet 12S and the second sheet 12H located in the non-bonded regions 90 swell away from each other in opposite directions to form pleats P continuing in the front-to-back direction LD, the height of the pleats P determines the cushioning properties. Here, when the following conditions are combined: (a) the bonded regions are wavy, (b) the spacing 90W between adjacent bonded portions 81 in the width direction WD is 7 to 14 mm, (c) the dimension 80W of the bonded portion 81 in the width direction WD is 0.04 to 0.3 times the spacing between adjacent bonded portions 81 in the width direction WD, (d) the total amplitude α of the side edges of the wavy bonded regions 80 is 0.2 to 0.7 times the spacing between adjacent bonded portions 81 in the width direction WD, and (e) the maximum elongation rate of the elastic region A2 in the width direction WD is 200 to 240%, In the natural length state, adjacent joints 81 in the width direction WD are not close to each other, and a certain distance is maintained between them, and as shown in Fig. 11(a) , thin folded pleats P are formed on either side of the gap in the width direction WD (the opposite side is omitted because it is merely symmetrical), or on one side of the base P1 or between the bases P1, with bases P1 on both sides not rising up enough to form pleats P, as shown in Fig. 12(a) . This principle can be explained as follows.That is, when the side edges of the first wavy line bonding region 80(L) and the second wavy line bonding region 80(R) adjacent to each other are looked at in the unfolded state, the side edge of the first wavy line bonding region 80(L) has a proximal peak LN protruding in a direction toward the second wavy line bonding region 80(R) and a distal peak LF protruding in the opposite direction. Similarly, the side edge of the second wavy line bonding region 80(R) has a proximal peak RN protruding in a direction toward the first wavy line bonding region 80(L) and a distal peak RF protruding in the opposite direction. As the elastic members 15, 17 contract, the side edges of the adjacent first wavy-line bonded regions 80(L) and the side edges of the second wavy-line bonded regions 80(R) approach each other in the width direction WD, forming folds P in the first sheet 12S and the second sheet 12H. Depending on the position in the front-to-back direction LD, one of the rising positions of the folds P may tend to follow the line connecting the proximal peaks LN of the first wavy-line bonded regions 80(L), or the other rising position of the folds P may tend to follow the line connecting the proximal peaks RN of the second wavy-line bonded regions 80(R), or both may occur. As a result, as shown in Figures 11(a) and 12(a), thinly folded pleats P are formed on one side of the bases P1 or between the bases P1, with bases P1 that do not rise enough to form pleats P on either or both sides of the gap between adjacent joints 81 in the width direction WD. The shape of the pleats P as viewed from the thickness direction is a wavy line along the center of the non-joined region 90 in the width direction WD. When such pleats P with bases P1 are stretched in the width direction WD and put into a worn state, the rising positions of the pleats P rise up and the folds at the boundaries between the pleats P and the bases P1 open, as shown in Figures 11(b) and 12(b), and therefore the reduction in height of the pleats P is small until the folds open. Furthermore, the shape of the pleats P when viewed from the thickness direction is a wavy line that runs along the center of the non-bonded region 90 in the width direction WD, and the only part that intersects perpendicularly with the width direction WD is the peak position, so the impact of the pleats P collapsing in the thickness direction is not easily transmitted to the direction in which the pleats P continue. This means that the pleats P are not easily collapsed. Therefore, in an elastic structure that satisfies the above conditions (a) to (e), the decrease in the height of the pleats P when worn is suppressed (in other words, the change in the height of the pleats P from the natural length state to the worn state is small), and the pleats P are not easily collapsed, which improves cushioning when worn.

[0077] In order to form a fold P with a base P1, it is preferable that, in the natural length state, the spacing between adjacent wavy bonding regions 80 in the width direction WD (equal to the spacing between adjacent bonding portions 81 in the width direction WD) is approximately 2 to 7 mm, particularly approximately 3 to 6 mm.

[0078] The wavy-line bonding region 80 preferably has a constant wavelength λ and total amplitude α of the side edges, as shown in the figure, because this ensures that the base P1 of the pleats P is regularly formed and provides even better cushioning when worn. However, these may vary. The wavy-line bonding region 80 may have a triangular wave shape, as shown in Figure 10(b), or a gentle curve with a continuous change in tangent slope (no straight or curved portions), such as a wave shape with alternating arcs or a sinusoidal wave, as shown in Figure 10(a). It may also have a wavy shape formed by a combination of straight portions 85 and curved portions 86, as shown in Figure 10(c). The wavy-line bonding region 80 may have a center line 82 with zero displacement of the side edges aligned in the front-to-rear direction, as shown in Figure 10, or may be inclined to have a small acute side crossing angle θ, e.g., 10 degrees or less, as shown in Figure 8. In addition, if the aforementioned improvement in cushioning is not required, instead of the wavy bonding area 80, a linear bonding area 89 may be used as shown in Figure 18, or a curved (arc-shaped, etc.) bonding area other than a wavy shape may be used, although this is not shown.

[0079] 8, in particular, when the wavy bonded regions 80 have a constant wavelength λ of the side edges, a constant total amplitude α of the side edges that is twice the single amplitude, an acute side crossing angle θ between the center line 82 where the displacement of the side edges is zero and the front-to-back direction LD is 3 to 7 degrees, and the dimension of the non-bonded regions 90 in the stretch direction is constant in the front-to-back direction LD, the pleats P are more resistant to crushing and the cushioning properties when worn are even better, which is preferable. Furthermore, when the bonded portions 81 are formed using ultrasonic welding, the stability of the welding quality is also excellent.

[0080] As shown in the illustrated example, when a stretchable structure in which the center line 82 of the wavy-line joining region 80, where the displacement of the side edges is zero, forms an acute-side crossing angle of 3 to 7 degrees with the front-to-back direction LD, is applied between the side seal regions 12A of the exterior bodies 12F, 12B of a pants-type disposable wearing article, when the product is in a natural length state in which the inner surface of the front body F faces and contacts the inner surface of the back body B, as shown in FIG. 13 , the center line 82 of the wavy-line joining region 80 in the stretchable structure of the exterior body 12F of the front body F and If the center lines 82 of the wavy joint regions 80 in the stretch structure of the outer body 12B of the back body B are inclined in the same direction relative to the front-to-back direction LD, when the inner surfaces of the front body F and the back body B are in contact with each other and in their natural length when the product is in its product state, the side seal regions 12A in the outer body 12B of the front body F and the back body B will deform into a parallelogram shape inclined in the same direction on either the left or right, and as a result, the shape of the waist area T when viewed from the front will also be the same, resulting in an imbalance in left-right balance in fit and appearance.

[0081] 14, if the center line 82 of the wavy-line joining region 80 in the stretch structure of the exterior body 12F of the front body F and the center line 82 of the wavy-line joining region 80 in the stretch structure of the exterior body 12B of the back body B are inclined in opposite directions relative to the front-to-back direction LD, when the inner surfaces of the front body F and the back body B are in contact with each other and at their natural lengths as a finished product, the deformation between the side seal regions 12A of the exterior body 12F of the front body F and the deformation between the side seal regions 12A of the exterior body 12F of the front body F will be in opposite directions, and although the inclination of the side seal regions 12A on the left and right will be in opposite directions, the shape of the waist region T when viewed from the front will be approximately rectangular. This results in a good left-right balance in fit and a good left-right balance in appearance, except for the inclination of the side seals.

[0082] The spacing 90W between adjacent joints 81 in the width direction WD, the dimension 80W of the joint 81 in the width direction WD, the total amplitude α of the side edge of the wavy joint region 80, the wave shape of the wavy joint region 80, the acute side intersection angle θ between the center line 82 at which the displacement of the side edge of the wavy joint region 80 is zero and the front-to-back direction LD, the dimension 90W of the non-joint region 90 in the width direction WD, etc. are preferably constant in the front-to-back direction LD, but any one, more than one, or all of them may vary.

[0083] When the joints 81 in each wavy-line bonding region 80 are provided intermittently in the front-rear direction LD in portions that do not intersect with the elastic members 15, the spacing in the front-rear direction LD can be determined as appropriate as long as a wavy-line region is formed when the side edges of adjacent joints 81 in the front-rear direction LD (orthogonal direction) are connected. As an example, as shown in Figures 8 and 9, the spacing 81D between adjacent joints 81 in the front-rear direction LD (orthogonal direction) is set to be shorter than the diameter of the elastic members 15 at their natural length in the front-rear direction LD throughout each wavy-line bonding region 80, and it is preferable that the joints 81 are in close contact with both sides of each elastic member 15 in the front-rear direction LD. In this case, as the elastic members 15 contract and expand in diameter, the portions of the elastic members 15 located at the fixing portions 84 are tightened and restrained by a cylindrical portion consisting of the joints 81 that are in close contact with the front and rear sides of the elastic members 15 and the portions between them. Therefore, as shown in FIG. 9( b), the entire first sheet 12S and the second sheet 12H may not be welded to the elastic member 15 at the fastening portion 84, and the elastic member 15 may be fixed only by frictional force between the inner surface of the tubular portion consisting of the joining portions 81 that are in close contact with both the front and rear sides of the elastic member 15 and the portion between them. However, as shown in FIG. 9( a), it is preferable that a portion 84m (or the entirety) of at least one of the first sheet 12S and the second sheet 12H is welded to the elastic member 15 at the fastening portion 84. This suppresses hardening due to welding, homogenizes the texture throughout each wavy-line joining region 80, and forms wavy-line pleats P with smooth contours. Furthermore, since a portion 84m (or the entirety) of at least one of the first sheet 12S and the second sheet 12H is welded to the elastic member 15 at the fastening portion 84, the elastic member 15 can be fixed more strongly than when the elastic member 15 is fixed only by friction. Of course, as long as the elastic member 15 is fixed by the fixing portion 84, the joint portions 81 may be provided at intervals equal to or greater than the diameter of the elastic member 15 at its natural length in the portions that do not intersect with the elastic member 15. In the illustrated example, the interval 81D between adjacent joint portions 81 in the front-to-rear direction LD (orthogonal direction) may be greater than, equal to, or slightly shorter than the diameter of the elastic member 15 in the deployed state.

[0084] On the other hand, when the bonded portions 81 in the wavy bonded region 80 are provided continuously in the front-to-back direction LD in portions that do not intersect with the elastic member 15, all such bonded portions 81 may be formed with a constant bond strength. However, since the weaker the bond strength by welding of a nonwoven fabric generally suppresses fiber melting and makes the fabric more flexible, for example, strong bonded portions with relatively high bond strength may be provided in the vicinity of both the front and back sides of the elastic member 15, and weak bonded portions with relatively low bond strength may be provided in other portions (not shown).

[0085] (Side Seal Region) In the side seal region 12A, the welding between both sides of the exterior body 12F on the front body F and both sides of the exterior body 12B on the back body B is preferably achieved by scattered welding points 70, as in the examples shown in Figures 15 to 18. These welding points 70 can be formed by ultrasonic welding or heat sealing in a predetermined pattern of welding points 70 while both sides of the exterior body 12F on the front body F and both sides of the exterior body 12B on the back body B are overlapped. A cross section of the side seal region for the example shown in Figure 5 is shown in Figure 20, and at the welding points 70, these sheets, etc. are welded together by applying pressure to the entire sheet in the thickness direction (pressure from both the left and right sides in the figure).

[0086] 15 and 19, the side seal region 12A preferably has a unit point group 71 in which welding points 70 at each vertex of an isosceles triangle it having a base along the width direction WD and a vertex located on the waist opening WO side are arranged at intervals, no welding points 70 are located on the sides of the unit point group 71, and the welding point 70 located most inward in the width direction WD of the unit point group 71 is the welding point 70 located most inward in the width direction WD of the side seal region 12A. Note that, in the unit point group 71, the welding points 70 being located at each vertex of the isosceles triangle it includes not only that the center of the welding points 70 (or the center of gravity in the case of a shape without a center) is located at each vertex, but also that parts other than the center of the welding points 70 are located at each vertex.

[0087] The dimension 71y in the front-rear direction LD of the unit point group 71 is preferably more than 1 time and not more than 3 times, more preferably 2 to 3 times, the dimension 70y in the front-rear direction LD of the welded point 70. The dimension 71x in the width direction WD of the unit point group 71 is preferably 3 to 15 times, more preferably 4 to 7 times, the dimension 70x in the width direction WD of the welded point 70. The spacing 71d in the front-rear direction LD of the unit point group 71 can be determined as appropriate. For example, it can be 0.2 to 3 times the dimension 70y in the front-rear direction LD of the welded point 70, or 1 to 2 times, particularly when there are welded points 70(S) other than the unit point group 71 described below, or 0.2 to 1 time, when there are no welded points 70(S) other than the unit point group 71 described below. The dimension 70y of the weld point 70 in the front-rear direction LD and the dimension 70x of the weld point 70 in the width direction WD may be determined appropriately, and may be set to, for example, 0.8 to 1.5 mm, and particularly 0.8 to 1.2 mm, respectively.

[0088] It is also preferable that no welding points 70 are present in the gap regions 72 between unit point groups 71 adjacent to each other in the front-rear direction LD, and in the side regions 73 of the unit point groups 71 .

[0089] With this pattern of weld points 70 in the side seal area 12A, when the side of the outer body 12F of the front body F and the side of the outer body 12B of the back body B are peeled away from the waist opening WO side in the side seal area 12A, the peeling mechanism of each unit point group 71 is repeated, and when peeling away each unit point group 71, the starting point is set to one weld point 70 located on the waist opening WO side, and the weld point 70 that is peeled away after the starting point is lined up in the width direction WD, so the direction of the peeling force is stable, both weld points 70 can be peeled away smoothly, and horizontal tearing towards the center in the width direction WD is less likely to occur. Peeling (separation) of each welded point 70 includes not only destruction (breakage) of the substrate of the entire periphery of the welded point 70 in either the exterior body 12F of the front body F or the exterior body 12B of the back body B, but also interfacial peeling between the exterior body 12F of the front body F and the exterior body 12B of the back body B at the welded point 70. It is preferable that the above-mentioned unit point group 71 be repeatedly provided at intervals in the front-to-back direction LD over the entire side seal region 12A, but it may be provided in only a partial range.

[0090] As shown in Figures 16 and 17, the side seal region 12A may not have any welded points 70 other than the unit point groups 71. In this case, the welded points 70 located on the outermost sides of the unit point groups 71 in the width direction WD become the welded points 70 located on the outermost sides of the side seal region 12A in the width direction WD. On the other hand, it is preferable that the side seal region 12A have one or more welded points 70(S) on the sides of the spacing regions 72 of adjacent unit point groups 71 in the front-to-rear direction LD. In this case, the welded points 70(S) other than the unit point groups 71 become the welded points 70 located on the outermost sides of the side seal region 12A in the width direction WD. This requires the welded points 70(S) located on the sides (outside the width direction WD) to be peeled when peeling from one unit point group 71 to the next, making it even less likely that lateral tearing toward the center in the width direction WD will occur. 19, it is preferable that the welded points 70(S) other than the unit point group 71 are located on an extension 74 of the hypotenuse of an isosceles triangle it formed by the unit point group 71. This includes not only that the centers (or the centers of gravity in the case of a shape without a center) of the welded points 70 other than the unit point group 71 are located on the extension 74 of the hypotenuse of the isosceles triangle it, but also that portions of the welded points 70 other than the center are located on the extension 74 of the hypotenuse of the isosceles triangle it. Furthermore, the distance d1 between the welded points 70(S) other than the unit point group 71 and the welded points 70 located on the sides of the unit point group 71 (the distance between the centers of gravity in the case of a shape without a center) is preferably 0.9 to 1.1 times, and more preferably 1 time (equal to), the distance d2 between the welded points 70 located on the waist opening WO side and the welded points 70 on the side of the unit point group 71 (the distance between the centers of gravity in the case of a shape without a center). In the example shown in FIG. 17, there are no welded points 70 other than the unit point group 71, but they may be included.

[0091] 17, the unit point groups 71 may be aligned in the front-to-rear direction LD without any misalignment in the width direction WD, but as shown in Figures 15, 16, 18, and 19, it is also preferable to have a unit point group set 75 consisting of a plurality of unit point groups 71 aligned in the front-to-rear direction LD, with the unit point groups 71 closer to the leg opening LO having a unit point group set 75 whose positions in the width direction WD are shifted laterally by a distance d3 less than the dimension of the welded portion in the width direction WD, and this unit point group set 75 is repeatedly provided in the front-to-rear direction LD in a rectangular area circumscribing all the unit point groups 71. In this case, when peeling from one unit point group 71 to the next unit point group 71, the peeling force is more likely to be directed to the side (outside the width direction WD), making it even less likely that horizontal tears will occur toward the center in the width direction WD. The shift distance d3 between adjacent unit point groups 71 in the unit point group set 75 (the center of the corresponding welding point 70, or the distance in the width direction WD between the centers of gravity in the case of a shape without a center) can be determined as appropriate, but it is preferably less than or equal to the dimension 70x in the width direction WD of the welding point 70, and particularly preferably 0.5 to 0.9 times the dimension 70x in the width direction WD of the welding point 70.

[0092] If the widthwise WD spacing 90W of the linear bonded regions 80, 89 is wider than the widthwise WD dimension of the side seal region 12A, as in the example described above, the linear bonded regions 80, 89 may not be positioned within the side seal region 12A or the excess portion 12R on either side of the side seal region 12A. In this case, the lateralmost fixing portions 84 of the elastic members 15, 17 may be positioned closer to the center in the widthwise WD than the side seal region 12A, potentially resulting in a localized shortening of the widthwise WD dimension of the stretchable region A2 (reduced stretchability). On the other hand, if the widthwise WD spacing of the linear bonded regions 80, 89 is within the widthwise WD dimension of the side seal region 12A, this problem does not occur, but the widthwise WD spacing of the linear bonded regions 80, 89 is limited. Furthermore, to secure the elastic members 15, 17 at the welded points 70 within the side seal region 12A, the welded points 70 can be densely spaced, but this may reduce the flexibility of the side seal region 12A. Therefore, as shown in Figures 15 to 18, when the spacing in the width direction WD of the linear joint areas 80, 89 is wider than the dimension in the width direction WD of the side seal area 12A, it is preferable to provide excess portions 12R that are not joined to each other and protrude from the side edges of the side seal area 12A on both sides of the outer body 12F in the front body F and on both sides of the outer body 12B in the back body B, as also shown in Figures 1 and 2, and to make the dimension in the width direction WD of the area including the side seal area 12A and the excess portions 12R more than 1 time but less than 2 times the spacing 90W in the width direction WD of the linear joint areas 80, 89. As a result, even if the linear bonding regions 80, 89 are not positioned within the side seal region 12A by making the spacing 90W in the width direction WD wider than the dimension in the width direction WD of the side seal region 12A, the linear bonding regions 80, 89 are present in the excess portion 12R on the sides thereof, thereby avoiding the above-mentioned problem. Note that, since the auxiliary fixation by the linear bonding regions 80, 89 in the excess portion 12R is preferably strong, it is preferable that a portion 84m (or the entirety) of at least one of the first sheet 12S and the second sheet 12H be welded to the elastic member 15 at the fixing portion 84, as described above.

[0093] Although the planar shape of the welded points 70 is a perfect circle in the illustrated example, it can be determined as appropriate. For example, the planar shape of the welded points 70 can be a polygon such as a triangle, a rectangle, or a pentagon, as well as an ellipse, a star, a cloud, or the like. In the case of welded points 70 with corners such as a polygon, it is preferable that the corners are rounded. It is preferable that the welded points 70 have a shape such as a perfect circle or a regular polygon, where the ratio of the dimension in the front-to-back direction LD to the dimension in the width direction WD is close to 1 (for example, less than 1.3).

[0094] The shape, size, and arrangement of the weld points 70 may be constant throughout the entire side seal region 12A, or the shape, size, and arrangement of the weld points 70 may be constant in a first range in the front-to-rear direction of the side seal region 12A, but may be different in a second range in the front-to-rear direction of the side seal region 12A from the first range. Also, weld points 70 that differ in at least one of shape and size may be present throughout part or the entire side seal region 12A.

[0095] <Cushioning property evaluation test> An exterior body having the structure shown in Figures 1 to 9 was manufactured, and cut in the front-to-rear direction at the center of the width of the front exterior body and the center of the width of the rear exterior body, and a test specimen was prepared in which the left half of the front exterior body and the left half of the rear exterior body were joined with a side seal.

[0096] (Example) First sheet: fineness 2.8 dtex, basis weight 15 g / m ２ , spunbond nonwoven fabric. Second sheet: fineness 2.8 dtex, basis weight 15 g / m ２ , spunbond nonwoven fabric. ・Spacing 90W between adjacent bonded portions 81 in the width direction WD: 11 mm. ・Dimension 80W of bonded portion 81 in the width direction WD: 1 mm. ・Total amplitude α of side edges of wavy bonded region: 4 mm. ・Maximum elongation in the width direction WD: 210%. ・Acute side crossing angle θ between center line 82 where displacement of side edges is zero and front-to-back direction LD: 5 degrees. ・Wavelength λ: 46 mm.

[0097] (Comparative Example) The conditions were the same as those of the example, except for the following: Distance 90W between adjacent joints 81 in the width direction WD: 5.5 mm. Acute side intersection angle θ between the center line 82 where the displacement of the side edge is zero and the front-rear direction LD: 0 degrees.

[0098] (Test Method) The specimens of the Examples and Comparative Examples were stretched in the width direction (three stretch rates: 135%, 150%, and 170%), and one cut end and the other cut end were fixed to a flat test plate with adhesive tape at 10 mm and 10 mm, respectively, and then subjected to compression tests using a Kato Tech compression tester (KES-G5) under the following conditions: T0: pressure 0.5 gf / cm ２ TM: sample thickness (mm) at time, and TM: maximum pressure 50 gf / cm ２ The thickness (mm) of the sample was measured at each time point, and the difference was calculated as an evaluation value of cushioning. The measurement was performed at the center of the front-to-back direction of five pleats having an average thickness, with the center of the compressor aligned with the apex of the pleat, and the average value was taken as the measured value. The measurement conditions were: DEF sensitivity: 20 mm / 10 V, compression area of ​​the compressor: 2 cm ２ (Standard accessory compression element), measurement load: 5.0 gf, sens: 2. Conditions not described here were the same for both the examples and comparative examples.

[0099] (Test Results) The test results are shown in Table 1. In the test specimens of the Examples, the decrease in the evaluation value of cushioning property was small at all elongation rates from 135% to 175%, whereas in the test specimens of the Comparative Examples, the evaluation value of cushioning property decreased as the elongation rate increased.

[0100] <Explanation of Terms Used in the Specification> The following terms used in the specification have the following meanings unless otherwise specified in the specification.

[0101] The "front-to-back direction" refers to the direction indicated by the symbol LD in the figure (vertical direction), and the "width direction" refers to the direction indicated by the symbol WD in the figure (left-to-right direction), and the front-to-back direction and the width direction are perpendicular to each other.

[0102] "Front side" means the side closest to the wearer's skin when the pants-type disposable diaper is worn, and "rear side" means the side farthest from the wearer's skin when the pants-type disposable diaper is worn.

[0103] "Front surface" means the surface of the component that is closest to the wearer's skin when the pants-type disposable diaper is worn, and "back surface" means the surface that is farthest from the wearer's skin when the pants-type disposable diaper is worn.

[0104] "Elongation rate" refers to a value when the natural length is 100%. For example, an elongation rate of 200% is equivalent to an elongation ratio of 2 times.

[0105] - "Basis weight" is measured as follows. After pre-drying the sample or test piece, it is left in a test room or device under standard conditions (test location: temperature 23±1°C, relative humidity 50±2%) until it reaches a constant weight. Pre-drying refers to bringing the sample or test piece to a constant weight in an environment at a temperature of 100°C. Note that pre-drying is not necessary for fibers with an official moisture regain of 0.0%. Using a sample collection template (100mm x 100mm), a sample measuring 100mm x 100mm is cut from the test piece when it has reached a constant weight. The weight of the sample is measured and multiplied by 100 to calculate the weight per square meter, which is the basis weight.

[0106] "Thickness" was measured using an automatic compression tester (KES-G5 manufactured by Kato Tech Co., Ltd.) with a load of 0.098 N / cm ２ , and pressure area: 2 cm ２ Automatic measurement is performed under the following conditions.

[0107] The water absorption amount is measured according to JIS K7223-1996 "Test method for water absorption amount of superabsorbent resins."

[0108] "Expanded state" means a state in which the material is stretched to its elastic limit (in other words, contracted (including any contraction such as contraction due to an elastic member) or deployed flat without slack).

[0109] "Maximum elongation rate" means the elongation rate in the unfolded state.

[0110] - Unless otherwise specified, the dimensions and positional relationships of each part refer to the dimensions and positional relationships in the unfolded state, not in the natural length state.

[0111] - If there is no description of the environmental conditions for a test or measurement, the test or measurement shall be carried out in a test room or device under standard conditions (the test location shall be a temperature of 23±1°C and a relative humidity of 50±2%).

[0112] The present invention can be used in pants-type disposable wearing articles such as pants-type disposable diapers and pants-type sanitary napkins.

[0113] 11...liquid-impermeable sheet, 12A...side seal region, 12B...rear outer body, 12E...waist extension portion, 12F, 12B...outer body, 12F...front outer body, 12H...second sheet, 12R...excess portion, 12S...first sheet, 13...cover nonwoven fabric, 15, 17...elastic member, 15...waist lower elastic member, 17...waist elastic member, 18...outer portion, 19...inner portion, 200...inner body, 201, 202...inner body fixing portion, 30...top sheet, 40...intermediate sheet, 50...absorbent element, 56...absorbent body, 58...packaging sheet, 60...rising gathers, 60A...tip side portion, 60B...base side portion, 62...gather nonwoven fabric, 67... fallen portion, 68... free portion, 70... welding point, 71... unit point group, 72... spacing region, 73... side region, 75... unit point group set, 80, 89... linear bonding region, 80... wavy bonding region, 81... bonding portion, 82... center line, 84... fixed portion, 90... non-bonded region, A1... non-stretch region, A2... stretch region, B... back body, C... buttocks cover portion, F... front body, HM... hot melt adhesive, L... middle region, LD... front and back direction, LO... leg opening, P... pleats, P1... base, T... waist region, U... lower waist portion, W... waist portion, WD... width direction, WO... waist opening, it... isosceles triangle, α... total amplitude, λ... wavelength.

Claims

1. A stretchable structure having a first sheet and a second sheet, and a plurality of elongated elastic members extending along the stretchable direction and spaced apart between the first and second sheets in a direction perpendicular to the stretchable direction, wherein the stretchable structure has a stretchable region, wherein wavy-line bonded regions that continue in the perpendicular direction across the elastic members are arranged intermittently in the stretchable direction in the stretchable region, and the entire area between adjacent wavy-line bonded regions in the stretchable direction is a non-bonded region, and portions of each wavy-line bonded region that do not intersect with the elastic members are provided with bonded portions where the first sheet and the second sheet are welded intermittently or continuously in the perpendicular direction, and portions of each wavy-line bonded region that intersect with the elastic members are fixed portions where the elastic members are fixed to the first sheet and the second sheet, the stretchable region is a region that elastically stretches and contracts between a natural length state in which it contracts in the stretch direction due to contraction of the elastic member, and portions of the first sheet and the second sheet located in the non-bonded region expand away from each other in opposite directions, forming pleats continuing in the orthogonal direction, and an expanded state in which it stretches together with the elastic member in the stretch direction to a maximum elongation rate and no pleats remain; the spacing between adjacent joints in the stretch direction is 7 to 14 mm; the dimension of the joints in the stretch direction is 0.04 to 0.3 times the spacing between adjacent joints in the stretch direction; the total amplitude of the side edges of the wavy-line bonded region is 0.2 to 0.7 times the spacing between adjacent joints in the stretch direction; and the maximum elongation rate of the stretchable region in the stretch direction is 200 to 240%.

2. The stretchable structure of a disposable wearing article according to claim 1, wherein all of the wavy-line bonding regions have a constant wavelength of the side edges, a constant total amplitude of the side edges that is twice the single amplitude, and an acute crossing angle between a center line at which the displacement of the side edges is zero and the orthogonal direction is 3 to 7 degrees.

3. The stretchable structure of a disposable wearing article according to claim 1 or 2, wherein the joints where the first sheet and the second sheet are welded are provided intermittently over the entirety of each of the wavy-line joint regions in the orthogonal direction at intervals shorter than the diameter of the elastic member at its natural length, the joints are in close contact with both sides of each elastic member in the orthogonal direction, and at least one of the first sheet and the second sheet is partly or entirely welded to the elastic member at the fixing portion.

4. A pants-type disposable wearing article having an annular waist region formed by joining both sides of a front body and both sides of a back body, an intermediate region extending from the waist region of the front body through a crotch region to the waist region of the rear body, a waist opening provided in the waist region on the opposite side of the intermediate region, and leg openings provided on both sides of the intermediate region in the width direction, the article comprising: an outer body forming at least the waist region; an inner body attached to the outer body so as to extend from the intermediate portion of the front body in the width direction to the intermediate portion of the back body in the width direction; and side seal regions where both sides of the outer body on the front body and both sides of the outer body on the back body are joined with their inner surfaces facing each other, wherein the outer body on at least one of the front body and the back body is provided with the stretchable structure according to claim 1 or 2 in part or all of the region between the side seal regions in the front-to-back direction and across the entire width direction between the side seal regions, with the stretchable direction of the stretchable region being the width direction of the pants-type disposable wearing article. A pants-type disposable wearing article characterized by:

5. The pants-type disposable wearing article of claim 4, wherein the outer body of the front body and the outer body of the back body are provided with the stretch structure of claim 2 in part or all of the area between the side seal areas in the front-to-back direction, and across the entire width between the side seal areas, and when viewed from the front in a product state in which the inner surfaces of the front body and the back body are in contact with each other and in their natural length, the center line of the wavy-line joint area in the stretch structure of the outer body of the front body and the center line of the wavy-line joint area in the stretch structure of the outer body of the back body are inclined in opposite directions with respect to the orthogonal direction.

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