Patent Description:
In general, an underpants-type disposable diaper includes an outer member for individually or integrally configuring a front body and a back body and an inner member having an absorbent body attached to the outer member to extend from the front body to the back body, and a waist opening and a pair of left and right leg openings are formed by joining both side edge portions of the outer member of the front body and both side edge portions of the outer member of the back body to form side seal portions.

In such an underpants-type disposable diaper, to improve fitting to a body, the outer member is configured to have a stacked structure including a plurality of sheet layers, and various elastic members are attached between the sheet layers in a stretched state. Especially, a diaper, in which elongated elastic members extending along a width direction are attached in a stretched state in the width direction with intervals in a front-back direction in lower torsos defined as front-back direction zones corresponding to side seal portions and an intermediate region located between front and back lower torsos, has relatively high fitting with respect to the body (for example, see Patent Literatures <NUM> to <NUM>).

The lower torsos and the intermediate region overlap the front-back direction zones having the absorbent body, and internal and external fixing portions for fixing the inner member to the outer member are present in the zones. Therefore, even when the elastic members are provided to traverse the front-back direction zones having the absorbent body, a stretching/contracting function thereof is limited by the rigidity of the absorbent body. In addition, there is concern that the absorbent body may contract in the width direction to degrade wearing feeling or appearance, or distortion or cracking of the absorbent body may occur to decrease absorption performance.

For this reason, in general, there has been conventionally adopted a scheme of continuously attaching elastic members along the width direction and finely cutting almost the entire part overlapping the absorbent body, or a scheme of not fixing an elastic member to the outer member in a part overlapping the absorbent body and cutting the part at one place in the middle in the width direction, thereby forming a non-stretchable region in which a contraction force in the width direction does not act on the absorbent body. As this cutting scheme, as a scheme in which holes are not formed in an inner sheet layer and an outer sheet layer covering an inside and an outside of the elastic member, a scheme of cutting the elastic member in a state of interposing the elastic member between the inner sheet layer and the outer sheet layer by pressing and heating a cut site from the inside and the outside thereof has been known.

On the other hand, a contraction force of the elastic member hardly acts and contraction wrinkles are rarely formed on the non-stretchable region of the outer member, and thus the non-stretchable region is excellent in light permeability when compared to a part in which contraction wrinkles are formed. Therefore, a display sheet having a pattern, etc. has been interposed between sheet layers of the outer member in the non-stretchable region (see Patent Literature <NUM>) or between the outer member and the inner member (see Patent Literature <NUM>). As a material of such a display sheet, a resin film has been suitably used from viewpoints of being inexpensive and enabling high-definition printing.

Here, in the case of interposing the display sheet between the sheet layers of the outer member, in a state in which the elastic member and the display sheet are disposed between the outer sheet layer and the inner sheet layer, the elastic member is cut by pressing and heating in a region having the display sheet to form the non-stretchable region. Thus, when the display sheet is formed of the resin film, there is concern that traces having concavo-convex figures may remain in the display sheet in the cut site of the elastic member, holes may be formed by tearing or melting, and thus these cutting traces may degrade the appearance of the display sheet.

Meanwhile, a mode in which the display sheet is interposed between the outer member and the inner member may be a particularly preferably mode in a case in which the resin film is used as the material of the display sheet since a process of cutting the elastic member for forming the non-stretchable region at the time of manufacture may be performed in a state of not having the display sheet.

However, the liquid impervious sheet made of the resin film is exposed in most of a region overlapping the display sheet on a back surface of the inner member. Further, when the display sheet is bonded to this portion through a hot melt adhesive, two resin films are directly bonded, and thus there is a problem that air permeability is lowered.

Therefore, a main problem of the invention is to achieve compatibility between prevention of deterioration of appearance of a display sheet and prevention of a decrease in air permeability in the case of using a resin film as a material of the display sheet.

Representative aspects of the invention solving the above-mentioned problems are as follows.

An underpants-type disposable diaper as claimed in claim <NUM>.

In this aspect, a mode in which the display sheet is interposed between the outer member and the inner member is adopted, and a process of cutting the elastic member for forming the non-stretchable region can be performed without the display sheet at the time of manufacture. Thus, it is possible to prevent deterioration of appearance of the display sheet. In addition, since the perforated nonwoven fabric extends at least from the crotch side edge of the outer member a region between the display sheet and the liquid impervious sheet on the waist opening side, and air can permeate through the inside of the perforated nonwoven fabric from the outside of the disposable diaper and to the region between the display sheet and the liquid impervious sheet, it is possible to prevent the deterioration of the air permeability when the resin film is used as the material of the display sheet.

The underpants-type disposable diaper according to the first aspect, in which the perforated nonwoven fabric is a cover nonwoven fabric which extends from a region between the front side outer member and the inner member to a region between the back side outer member and the inner member and covers a back surface of the inner member in a site in which the front side outer member and the back side outer member are spaced apart.

In an outer member separated type underpants-type disposable diaper in which the front side outer member and the back side outer member are spaced apart in the front-back direction, the inner member is exposed between the front side outer member and the back side outer member, and thus it is known to cover the back surface of the inner member with the cover nonwoven fabric so that the liquid impervious sheet is not exposed on the back surface of the inner member. This aspect is used both as the cover nonwoven fabric that covers the back surface of the inner member and the perforated nonwoven fabric disposed between the display sheet and the liquid impervious sheet, and a single perforated nonwoven fabric can cover the back surface of the inner member and improve air permeability of a part having the display sheet.

The underpants-type disposable diaper according to the second aspect, further comprising.

Since the both side portions of the perforated nonwoven fabric are covered with the gather nonwoven fabric, the both side portions of the perforated nonwoven fabric are rarely peeled off from the liquid impervious sheet.

The underpants-type disposable diaper according to any one of the first to third aspects, in which an inner and outer joined portion that joins the inner member and the outer member overlapping the perforated nonwoven fabric is provided over a region overlapping the perforated nonwoven fabric and a region on both width-direction sides beyond the overlapping region.

In this case, it is possible to firmly fix the both side portions of the perforated nonwoven fabric, and the both side portions of the perforated nonwoven fabric are rarely peeled off from the inner member.

The underpants-type disposable diaper according to any one of the first to fourth aspects, in which the hot melt adhesive is not present on a center side of a peripheral edge portion of a region overlapping the holes, and the hot melt adhesive is applied in a continuous surface shape in a portion other than the peripheral edge portion of the region overlapping the holes, in a bonded region of at least one of the internal surface and the external surface of the perforated nonwoven fabric.

When such a bonding structure is adopted, the hot melt adhesive is not present on the center side of the peripheral edge portion in the region overlapping the holes, and thus air permeability is excellent. In addition, in a portion having such a bonding structure only on a surface opposite from a surface to be touched by the skin, a sticky texture due to the hot melt adhesive is rarely obtained, and the peripheral portion of the hole is reliably fixed to the facing surface. Since the peripheral edge portion of the region overlapping the hole is a portion close to the peripheral portion of the hole, even when the hot melt adhesive protrudes to this portion, the hot melt adhesive is rarely directly touched at the time of touching the surface on the opposite side from a bonded surface in the perforated nonwoven fabric with a hand.

The underpants-type disposable diaper according to any one of the first to fourth aspects, in which.

When such a bonding structure is adopted, the bonded area decreases, and thus flexibility is not impaired, and the peripheral portion of the hole is reliably fixed to the facing surface on the liquid impervious sheet side. In particular, the warped portion supports the perforated nonwoven fabric with respect to the facing surface on the liquid impervious sheet side as a post, and thus is bulky in comparison with a non-porous nonwoven fabric having the same basis weight, and is excellent in air permeability.

As described above, the invention is advantageous in that it is possible to achieve compatibility between prevention of deterioration of appearance of a display sheet and prevention of a decrease in air permeability in the case of using a resin film as a material of the display sheet.

Hereinafter, an embodiment of the invention will be described in detail with reference to accompanying drawings. A dotted pattern portion in a cross-sectional view illustrates an adhesive as bonding means for bonding respective constituent members located on a front surface side and a back surface side thereof, and is formed by solid coating, bead coating, curtain coating, summit coating, or spiral coating of a hot melt adhesive, pattern coating (transfer of a hot melt adhesive in a relief printing method), etc. Alternatively, a fixing part of the elastic member is formed by application of a hot melt adhesive to an outer circumferential surface using comb gun or sure-wrap application in place of or together with the above schemes. Examples of the hot melt adhesive include various types of adhesives such as EVA-based adhesive, adhesive rubber-based (elastomer-based), polyolefin-based, and polyester/polyamide-based adhesives, which can be used without particular limitation. As the bonding means for bonding the respective constituent members, it is possible to use means by material welding such as heat sealing or ultrasonic sealing.

<FIG> illustrate an example of an underpants-type disposable diaper. The underpants-type disposable diaper includes a front side outer member 12F forming at least a lower torso portion of a front body F, a back side outer member 12B forming at least a lower torso portion of a back body B, and an inner member <NUM> provided on an inner side of the outer members 12F and 12B to extend from the front side outer member 12F to the back side outer member 12B through a crotch portion. Both side portions of the front side outer member 12F and both side portions of the back side outer member 12B are joined to form side seal portions 12A, so that an opening formed by front and back end portions of the outer members 12F and 12B becomes a waist opening WO passing through a truck of a wearer, and portions surrounding by lower edges of the outer members 12F and 12B and a side edge of the inner member <NUM> at both sides of the inner member <NUM> in a width direction become leg openings LO passing through legs. The inner member <NUM> is a portion that absorbs and holds excrement such as urine and the outer members 12F and 12B are portions for supporting the inner member <NUM> with respect to a body of the wearer. In addition, a symbol Y indicates an entire length of the diaper in a spread state (a length in a front-back direction from the edge of the waist opening WO of the front body F to the edge of the waist opening WO of the back body B), and a symbol X indicates an entire width of the diaper in the spread state.

The underpants-type disposable diaper of this embodiment includes lower torsos T defined as front-back direction zones having the side seal portions 12A (front-back direction zones from the waist opening WO to upper ends of the leg openings LO) and an intermediate region L defined as a front-back direction zone of portions forming the leg openings LO (between a front-back direction region having the side seal portions 12A of the front body F and a front-back direction region having the side seal portions 12A of the back body B). Each of the lower torsos T can be divided into a "waist portion" W conceptually forming the edge portion of the waist opening and an "lower waist portion" U corresponding to a portion on a lower side thereof. Normally, when a boundary at which stretching stress in the width direction WD changes (for example, a fineness or a stretch rate of the elastic member changes) is included in the lower torso T, the waist opening WO side closest to the boundary is the waist portion W. When such a boundary is not present, a waist opening WO side of an absorbent body <NUM> or the inner member <NUM> is the waist portion W. Lengths thereof in the front-back direction vary depending on the size of the product and may be appropriately determined. For example, the waist portion W can be set to <NUM> to <NUM>, and a lower waist portion U can be set to <NUM> to <NUM>. Meanwhile, both side edges of the intermediate region L are narrowed in a U shape or a curved shape to follow circumferences of the legs of the wearer, and correspond to sites in which the legs of the wearer are put. As a result, the underpants-type disposable diaper in the spread state has a substantially hourglass shape as a whole.

An arbitrary shape can be adopted for the inner member <NUM>. However, a rectangle is adopted in an illustrated embodiment. As illustrated in <FIG>, the inner member <NUM> includes a top sheet <NUM> corresponding to a body side, a liquid impervious sheet <NUM>, and an absorbent element <NUM> interposed therebetween, and is a main unit section responsible for an absorption function. Reference numeral <NUM> denotes an intermediate sheet (second sheet) provided between the top sheet <NUM> and the absorbent element <NUM> to promptly transfer a liquid permeating through the top sheet <NUM> to the absorbent element <NUM>, and reference numeral <NUM> denotes side gathers <NUM> extending from both side portions of the inner member <NUM> to come into contact with a periphery of the legs of the wearer so as to prevent excrement from leaking to both sides of the inner member <NUM>.

The top sheet <NUM> has a property of permeating liquid, and examples thereof may include a perforated or nonporous nonwoven fabric, a porous plastic sheet, etc. In addition, a raw material fiber of the nonwoven fabric is not particularly restricted. Examples thereof may include a synthetic fiber such as a polyolefin synthetic fiber such as polyethylene, polypropylene, etc., a polyester synthetic fiber, a polyamide synthetic fiber, etc., a regenerated fiber such as rayon or cupra, a natural fiber such as cotton, or a mixed fiber, a composite fiber, etc. using two types or more thereof. Further, the nonwoven fabric may be manufactured by any process. Examples of a processing method may include a known method such as a spun lace method, a spun bond method, a thermal bond method, a melt blown method, a needle-punch method, an air-through method, a point bond method, etc. For example, when flexibility and drapeability are required, the spun bond method and the spun lace method are preferable processing schemes. Further, when bulkiness and softness are required, the air-through method, the point bond method, and the thermal bond method are preferable processing schemes.

In addition, the top sheet <NUM> may be made of one sheet or a stacked sheet obtained by bonding two or more sheets. Similarly, the top sheet <NUM> may be made of one sheet or two or more sheets in a plane direction.

Both side portions of the top sheet <NUM> may be folded back to the back surface side at side edges of the absorbent element <NUM> or may laterally protrude beyond the side edges of the absorbent element <NUM> without folding back.

For the purpose of preventing positional shift with respect to the back surface side member, etc., it is desirable that the top sheet <NUM> is fixed to a member adjacent to the back surface side by bonding means based on material welding such as heat sealing or ultrasonic sealing or a hot melt adhesive. In the illustrated embodiment, the top sheet <NUM> is fixed to a surface of the intermediate sheet <NUM> and a surface of a portion of a package sheet <NUM> located on the front surface side of the absorbent body <NUM> by a hot melt adhesive applied to the back surface thereof.

To rapidly transfer the liquid permeating through the top sheet <NUM> to the absorbent body, it is possible to provide an intermediate sheet (also referred to as a "second sheet") <NUM> having a higher liquid permeation rate than that of the top sheet <NUM>. The intermediate sheet <NUM> serves to rapidly transfer the liquid to the absorbent body to enhance an absorption performance of the absorbent body, and to prevent a "back-flow" phenomenon of the absorbed liquid from the absorbent body. The intermediate sheet <NUM> can be omitted.

Examples of the intermediate sheet <NUM> may include a similar material to that of the top sheet <NUM>, spun lace, spun bond, SMS, pulp nonwoven fabric, a mixed sheet of pulp and rayon, point bond or crepe paper. In particular, air-through nonwoven fabric is bulky, and thus is preferable. It is preferable to use a composite fiber having a core-sheath structure for the air-through nonwoven fabric. In this case, a resin used for a core may be polypropylene (PP). However, polyester (PET) having high rigidity is preferable. A basis weight is preferably <NUM> to <NUM>/m<NUM>, more preferably <NUM> to <NUM>/m<NUM>. A thickness of a raw material fiber of the nonwoven fabric is preferably <NUM> to <NUM> dtex. In order to increase the bulkiness of the nonwoven fabric, it is preferable to use an eccentric fiber having no core in a center, a hollow fiber, and an eccentric and hollow fiber as a mixed fiber of a whole or a part of the raw material fiber.

The intermediate sheet <NUM> of the illustrated embodiment is shorter than a width of the absorbent body <NUM> and disposed at a center. However, the intermediate sheet <NUM> may be provided over the whole width. A length of the intermediate sheet <NUM> in the front-back direction may be equal to the entire length of the diaper, equal to a length of the absorbent element <NUM> or within a short length range centered on a region in which a liquid is received.

For the purpose of preventing positional shift with respect to the back surface side member, etc., it is desirable that the intermediate sheet <NUM> is fixed to a member adjacent to the back surface side by bonding means based on material welding such as heat sealing or ultrasonic sealing or a hot melt adhesive. In the illustrated embodiment, the intermediate sheet <NUM> is fixed to a surface of a portion of the package sheet <NUM> located on the front surface side of the absorbent body <NUM> by a hot melt adhesive applied to the back surface thereof.

A material of the liquid impervious sheet <NUM> is not particularly limited. However, examples thereof may include a plastic film made of a polyolefin resin such as polyethylene, polypropylene, etc., a laminated nonwoven fabric having a plastic film provided on a surface of a nonwoven fabric, a stacked sheet in which a nonwoven fabric, etc. is overlapped with and joined to a plastic film, etc. A material having liquid impermeability and moisture permeability which has been favorably used from the viewpoint of prevention of unevenness is preferably used for the liquid impervious sheet <NUM>. A microporous plastic film obtained by kneading an inorganic filler in a polyolefin-based resin such as polyethylene or polypropylene, molding a sheet, and then performing stretching in a monoaxial or biaxial direction is widely used as the plastic film having moisture permeability. In addition, a nonwoven fabric using a micro-denier fiber, and a liquid impervious sheet obtained without using the plastic film by a method such as strengthening a leakage prevention property by reducing gaps of fibers by applying heat or pressure, use of a super absorbent resin or a hydrophobic resin, and coating of a water repellent agent may be used as the liquid impervious sheet <NUM>. However, it is desirable to use a resin film to obtain sufficient bonding strength at the time of bonding to a cover nonwoven fabric <NUM> described below via a hot melt adhesive.

As illustrated in the figure, the liquid impervious sheet <NUM> has a width that fits on the back surface side of the absorbent element <NUM>. In addition, to enhance a leakage prevention property, both sides of the absorbent element <NUM> may be wrapped to extend to both side portions of a surface of the absorbent element <NUM> on the top sheet <NUM> side. It is appropriate that a width of this extended portion is about <NUM> to <NUM> on both left and right sides.

In addition, an excretion indicator whose color changes due to absorption of a liquid component can be provided inside the liquid impervious sheet <NUM>, particularly on the side of the absorbent body <NUM>.

The side gathers <NUM> extend along the both side portions of the inner member <NUM> over the whole in a front-back direction LD and are provided to prevent side leak by coming into contact with the peripheries of the legs of the wearer. In general, the side gathers <NUM> includes gathers referred to as three-dimensional gathers or gathers referred to as planar gathers.

The side gathers <NUM> of the first embodiment illustrated in <FIG>, <FIG>, and <FIG> are so-called three-dimensional gathers, and stand from side portions of the inner member <NUM> to the front surface side. In the side gathers <NUM>, root side parts 60B obliquely stand toward a center side in the width direction, and tip side parts 60A with respect to an intermediate portion obliquely stand outward in the width direction. However, the invention is not limited thereto. As in a second embodiment described below, the embodiment may be appropriately changed to an embodiment in which the parts stand to the center side in the width direction as a whole.

More specifically, the side gathers <NUM> of the first embodiment are obtained by folding back belt-shaped gather nonwoven fabrics <NUM> having an equal length to a front-back direction length of the inner member <NUM> in the width direction WD in two parts at a portion corresponding to a tip, and fixing a plurality of elongated gather elastic members <NUM> with intervals in the width direction WD in a stretched state along a longitudinal direction between a folded portion and a sheet in the vicinity thereof. In the side gathers <NUM>, a base portion located on an opposite side from a tip portion (an end portion on an opposite side from the sheet folded portion in the width direction WD) is set as a root portion <NUM> fixed to a side portion on a back surface side of the liquid impervious sheet <NUM> in the inner member <NUM>, and a portion other than the root portion <NUM> is set as a main unit portion <NUM> (a portion on a side of the folded portion) extending from the root portion <NUM>. In addition, the main unit portion <NUM> includes a root side part 60B extending to the center side in the width direction and a tip side part 60A folded back at a tip of the root side part 60B to extend outward in the width direction. This embodiment corresponds to side gathers <NUM> of a surface contact type. However, it is possible to adopt side gathers <NUM> of a line contact type which are not folded back outward in the width direction. Further, in the main unit portion <NUM>, both end portions in the front-back direction are set as fallen parts <NUM> fixed to side surfaces of the top sheet <NUM> in a fallen state, and an intermediate portion in the front-back direction located therebetween is set as a free part <NUM> which is not fixed. The gather elastic members <NUM> extending along the front-back direction LD are fixed to at least a tip portion of the free part <NUM> in a stretched state.

In the side gathers <NUM> of the first embodiment configured as described above, a contraction force of the gather elastic members <NUM> acts so that the both end portions in the front-back direction approach to each other. However, since the both end portions in the front-back direction in the main unit portion <NUM> are fixed not to stand, and a part therebetween is set as the free part <NUM> which is not fixed, only the free part <NUM> stands to come into contact with the body side as illustrated in <FIG>.

In particular, when the root portion <NUM> is located on the back surface side of the inner member <NUM>, the free part <NUM> stands to open outward in the width direction in the crotch portion and the vicinity thereof. Thus, the side gathers <NUM> come into surface contact with the peripheries of the legs, and fitting is improved.

In a bending mode in which the main unit portion <NUM> includes the root side part 60B extending to the center side in the width direction and the tip side part 60A folded back at the tip of the root side part 60B to extend outward in the width direction as in the side gathers <NUM> of the first embodiment, the tip side part 60A and the root side part 60B are bonded together in a fallen state in the fallen part <NUM>, and the root side part 60B is bonded to the top sheet <NUM> in a fallen state. For bonding facing surfaces in the fallen part <NUM>, it is possible to use at least one of a hot melt adhesive based on various coating methods and means based on material welding such as heat sealing, ultrasonic sealing, etc. In this case, bonding between the root side part 60B and the top sheet <NUM> and bonding between the tip side part 60A and the root side part 60B may be performed by the same means or different means. For example, in a preferable embodiment, bonding between the root side part 60B and the top sheet <NUM> is performed by the hot melt adhesive, and bonding between the tip side part 60A and the root side part 60B is performed by material welding.

In particular, in an outer member separated type underpants-type disposable diaper in which the front side outer member 12F and the back side outer member 12B are spaced apart in the front-back direction LD, as illustrated in <FIG>, it is preferable to provide a front side half fallen part 68F in which the root side part 60B is bonded to the top sheet <NUM> in a fallen state continuously or adjacent to a back side of a front side fallen part <NUM>, and the tip side part 60A and the root side part 60B are not bonded together. In the front side half fallen part 68F, only the tip side part 60A is free. Thus, even though a height is low, the tip portion reliably rises with respect to the top sheet <NUM> by contraction of the gather elastic member <NUM>. Therefore, fitting of the side gather <NUM> is excellent for an inguinal region in which a gap is likely to be generated. In addition, in this case, it is more preferable that the front side half fallen part 68F is the same as a back edge of the front side outer member 12F or extends to the center side in the front-back direction therefrom (that is, the front side half fallen part 68F includes an intersection position of the front side outer member 12F and the inner member <NUM>). In a normal case, it is preferable that a length of the front side fallen part <NUM> in the front-back direction is about <NUM> to <NUM> times a length of the inner member <NUM> in the front-back direction, and a dimension obtained by adding a length of the front side half fallen part 68F in the front-back direction thereto is about <NUM> to <NUM> times the length of the inner member <NUM> in the front-back direction. In <FIG>, reference symbol AF denotes the hot melt adhesive that bonds the tip side part 60A and the root side part 60B, and reference symbol BF denotes the hot melt adhesive that bonds the root side part 60B and the top sheet <NUM>.

In addition, as illustrated in <FIG>, when a back side half fallen part 68B in which the tip side part 60A is bonded to the root side part 60B in a fallen state continuously or adjacent to a front side of a back side fallen part <NUM>, and the root side part 60B and the top sheet <NUM> are not bonded together is provided, only the root side part 60B is free, and the tip side part 60A is not fixed. Thus, the tip side part 60A of the three-dimensional gather rarely falls in an opposite direction due to an inclination toward an intergluteal cleft, which is preferable. (Since the back side half fallen part 68B comes into contact with a bulging portion of a buttock, even when the tip side part 60A is fixed, there is no concern that a gap may be generated between a body and the part). In addition, in this case, it is more preferable that the back side half fallen part 68B is the same as a front edge of the back side outer member 12B or extends to the center side in the front-back direction therefrom (that is, the back side half fallen part 68B includes an intersection position of the back side outer member 12B and the inner member <NUM>). Further, in this case, it is preferable that a length of the back side half fallen part 68B in the front-back direction is longer than a length of the back side fallen part <NUM> in the front-back direction. In a normal case, it is preferable that a length of the back side fallen part <NUM> in the front-back direction is about <NUM> to <NUM> times a length of the inner member <NUM> in the front-back direction, and a dimension obtained by adding a length of the back side half fallen part 68B in the front-back direction thereto is about <NUM> to <NUM> times the length of the inner member <NUM> in the front-back direction. In <FIG>, reference symbol AF denotes the hot melt adhesive that bonds the tip side part 60A and the root side part 60B, and reference symbol BF denotes the hot melt adhesive that bonds the root side part 60B and the top sheet <NUM>.

As the gather nonwoven fabric <NUM>, it is possible to use preferably a material obtained by performing a water repellent treatment on a nonwoven fabric which is flexible and excellent in uniformity/concealing property such as spun bond nonwoven fabric (SS, SSS, etc.), SMS nonwoven fabric (SMS, SSMMS, etc.), melt blown nonwoven fabric, etc. using silicone, etc. as necessary, and a fiber basis weight is preferably set to about <NUM> to <NUM>/m<NUM>. Rubber thread, etc. may be used as the gather elastic members <NUM>. In the case of using spandex rubber thread, a fineness is preferably <NUM> to <NUM>,<NUM> dtex, more preferably <NUM> to <NUM> dtex. A stretch rate at the time of fixing is preferably <NUM> to <NUM>%, more preferably <NUM> to <NUM>%. It should be noted that the term "stretch rate" means a value when a natural length is taken as <NUM>%. In addition, as illustrated in the figure, a waterproof film <NUM> may be interposed between two parts obtained by folding the gather nonwoven fabric <NUM>. In this case, the gather nonwoven fabric <NUM> may be partially omitted in a portion in which the waterproof film <NUM> is present. However, to make appearance and texture of a product like cloth, it is necessary that an external surface at least from the base to the tip of the side gather <NUM> is formed by the gather nonwoven fabric <NUM> as in the illustrated embodiment.

The number of gather elastic members <NUM> provided in the free part of the side gather <NUM> is preferably <NUM> to <NUM>, more preferably <NUM> to <NUM>. An appropriate arrangement interval 60d is <NUM> to <NUM>. When such a configuration is adopted, surface contact with a skin is easy in a range in which the gather elastic members <NUM> are disposed. The gather elastic members <NUM> may be disposed not only on the tip side but also on the root side.

In the free part <NUM> of the side gather <NUM>, it is possible to use at least one of the hot melt adhesive based on various coating methods and fixing means based on material welding such as heat sealing, ultrasonic sealing, etc., for bonding of an internal layer and an external layer of the gather nonwoven fabric <NUM> and fixing of the gather elastic member <NUM> interposed therebetween. When the entire surfaces of the internal layer and the external layer of the gather nonwoven fabric <NUM> are bonded, flexibility is impaired. Thus, it is preferable that a portion other than a bonded portion of the gather elastic member <NUM> is not bonded or is weakly bonded. In the illustrated embodiment, the hot melt adhesive is applied only to the outer circumferential surface of the gather elastic member <NUM> by coating means such as a comb gun or a sure-wrap nozzle and interposed between the internal layer and the external layer of the gather nonwoven fabric <NUM>, thereby performing fixing of the elongated elastic member to the internal layer and the external layer of the gather nonwoven fabric <NUM> and fixing of the gather nonwoven fabric <NUM> between the internal layer and the external layer only by the hot melt adhesive applied to the outer circumferential surface of the gather elastic member <NUM>.

Similarly, for fixing of the waterproof film <NUM> and the gather nonwoven fabric <NUM> incorporated in the side gather <NUM> and fixing of the fallen part <NUM>, it is possible to use at least one of a hot melt adhesive based on various coating methods and means based on material welding such as heat sealing, ultrasonic sealing, etc..

A dimension of the side gather <NUM> of the first embodiment may be appropriately determined. However, in the case of an infant disposable diaper, for example, as illustrated in <FIG>, it is preferable that a standing height of the side gather <NUM> (a length of the main unit portion <NUM> in the width direction in the spread state) W2 is <NUM> to <NUM>, and particularly <NUM> to <NUM>. In addition, in a state in which the side gather <NUM> is folded flat to be parallel to the surface of the top sheet <NUM>, it is preferable that a distance W1 between innermost folds is <NUM> to <NUM>, and particularly <NUM> to <NUM>.

The side gather <NUM> of the first embodiment includes only the three-dimensional gather. However, the side gather <NUM> may include both the three-dimensional gather and the planar gather or include only the planar gather. <FIG> and <FIG> illustrate the side gather <NUM> of the second embodiment including both the three-dimensional gather and the planar gather. Each side gather <NUM> includes a first portion <NUM> (planar gather portion) protruding to a side of the inner member <NUM> from the root portion <NUM> fixed to a side portion on the back surface side of the liquid impervious sheet <NUM> in the inner member <NUM>, and a second portion <NUM> (three-dimensional gather portion) protruding to the front surface side of the inner member <NUM> from the root portion <NUM> fixed to the both side portions of the top sheet <NUM> in the inner member <NUM>. More specifically, the belt-shaped gather nonwoven fabric <NUM> having a length equal to the length of the inner member <NUM> in the front-back direction extends to a side from the root portion <NUM> and is folded back to the front surface side at a tip of the first portion <NUM>, and a portion folded back to the front surface side reaches the second portion <NUM> through the first portion <NUM> and is folded back at a tip of the second portion <NUM>. In a folded portion in the gather nonwoven fabric <NUM>, facing portions are bonded by the hot melt adhesive, etc. In addition, both end portions of the second portion <NUM> in the front-back direction are set as the fallen parts <NUM> fixed to the side surface of the top sheet <NUM> in the fallen state, and an intermediate portion in the front-back direction positioned therebetween is set as the free part <NUM> which is not fixed. In at least the intermediate portion of the first portion <NUM> in the front-back direction and the free part <NUM> of the second portion <NUM>, one gather elastic member <NUM> or a plurality of gather elastic members <NUM> with intervals in the width direction WD extending along the front-back direction LD is fixed in a stretched state, the free part <NUM> of the second portion <NUM> contracts in the front-back direction LD by a contraction force thereof to become a three-dimensional gather coming into contact with the periphery of the leg, and the first portion <NUM> contracts in the front-back direction LD to become a planar gather coming into contact with the periphery of the leg.

The three-dimensional gather in the side gather <NUM> of the second embodiment has a mode of standing to the center side in the width direction as a whole. However, the invention is not limited thereto, and it is possible to make an appropriate change by adopting the bending mode as in the side gather <NUM> of the first embodiment. Other points related to the second embodiment, for example, the material of the gather nonwoven fabric <NUM>, the material of the gather elastic member <NUM>, etc. are the same as those in the first embodiment, and a description thereof will be omitted.

The absorbent element <NUM> includes the absorbent body <NUM> and the package sheet <NUM> wrapping the entire absorbent body <NUM>. The package sheet <NUM> may be omitted.

The absorbent body <NUM> can be formed by an assembly of fibers. As this fiber assembly, it is possible to use one obtained by accumulating short fibers of fluff pulp, synthetic fibers, etc., and a filament assembly obtained by opening a tow (fiber bundle) of synthetic fibers such as cellulose acetate as necessary. A fiber basis weight may be set to, for example, about <NUM> to <NUM>/m<NUM> in the case of accumulating fluff pulp or short fibers, and may be set to, for example, about <NUM> to <NUM>/m<NUM> in the case of the filament assembly. In the case of a synthetic fiber, the fineness is, for example, <NUM> to <NUM> dtex, preferably <NUM> to <NUM> dtex, more preferably <NUM> to <NUM> dtex. In the case of the filament assembly, the filaments may be non-crimped fibers, and are preferably crimped fibers. A degree of crimp of the crimped fibers can be set to, for example, about <NUM> to <NUM>, preferably about <NUM> to <NUM>, and more preferably about <NUM> to <NUM> per <NUM>. In addition, crimped fibers which are uniformly crimped are used in many cases. It is preferable to disperse and retain super absorbent polymer particles in the absorbent body <NUM>.

The absorbent body <NUM> may have a rectangular shape. However, when it has an hourglass shape having a narrower portion 56N whose width is narrower than that of both front and back sides in the middle in the front-back direction as illustrated in <FIG>, <FIG>, etc., fitting of the legs of the absorbent body <NUM> and the side gathers <NUM> to the peripheries is improved, which is preferable.

In addition, a dimension of the absorbent body <NUM> may be appropriately determined as long as the absorbent body <NUM> extends over a front, a back, a left, and a right of a ureteral outlet position. However, it is preferable that the absorbent body <NUM> extends to a peripheral edge portion of the inner member <NUM> or a vicinity thereof in the front-back direction LD and the width direction WD. Reference numeral 56X denotes a maximum width of the absorbent body <NUM>.

A super absorbent polymer particle may be contained in a part or a whole of the absorbent body <NUM>. The super absorbent polymer particle includes "powder" in addition to a "particle". A particle used in this type of disposable diapers may be used as the super absorbent polymer particle <NUM> without change. For example, it is desirable that the proportion of particles remaining on the sieve is <NUM> wt% or less by sieving (shaking for <NUM> minutes) using a <NUM> standard sieve (JIS Z <NUM>-<NUM>: <NUM>), and it is desirable that the proportion of particles remaining on the sieve is <NUM> wt% or more by sieving (shaking for <NUM> minutes) using a <NUM> standard sieve (JIS Z <NUM>-<NUM>: <NUM>).

A material of the super absorbent polymer particle may be used without particular limitation. However, a material having a water absorption capacity of <NUM>/g or more is suitable. Examples of the super absorbent polymer particle include starch-based, cellulose-based and synthetic polymer-based ones, and it is possible to use a starch-acrylic acid (salt) graft copolymer, a saponified starch-acrylonitrile copolymer, crosslinked sodium carboxymethylcellulose, an acrylic acid (salt) polymer, etc. A normally used granular shape is suitable for a shape of the super absorbent polymer particle. However, another shape may be used.

A particle having a water absorption rate of <NUM> seconds or less, particularly <NUM> seconds or less is suitably used as the super absorbent polymer particle. When the water absorption rate is excessively low, so-called back-flow, in which a liquid supplied into the absorbent body <NUM> returns to the outside of the absorbent body <NUM>, is likely to occur.

In addition, as the super absorbent polymer particle, one having a gel strength of <NUM> Pa or more is preferably used. In this way, even when the absorbent body <NUM> is bulky, a sticky feeling after liquid absorption can be effectively suppressed.

A basis weight amount of the super absorbent polymer particle may be appropriately determined according to the absorption amount required for the use of the absorbent body <NUM>. Therefore, even though it cannot be said unconditionally, the basis weight amount may be set to <NUM> to <NUM>/m<NUM>. When the basis weight amount of the polymer is less than <NUM>/m<NUM>, it is difficult to ensure the absorption amount. When the basis weight amount exceeds <NUM>/m<NUM>, the effect is saturated.

As necessary, a distribution density or a distribution amount of the super absorbent polymer particle may be adjusted in the plane direction of the absorbent body <NUM>. For example, the distribution amount may be increased in a liquid excretion site than in other sites. In the case of considering a difference between men and women, it is possible to raise the distribution density (amount) on the front side for men and to raise the distribution density (amount) in the central part for women. Further, it is possible to provide a portion in which no polymer is present locally (for example, in a spot shape) in the planar direction of the absorbent body <NUM>.

When the package sheet <NUM> is used, it is possible to use tissue paper, particularly crepe paper, nonwoven fabric, poly-laminate nonwoven fabric, a sheet having an open small hole, etc. as a material thereof. However, it is desirable that the sheet is a sheet from which the super absorbent polymer particle does not come off. When a nonwoven fabric is used in place of crepe paper, a hydrophilic SMS nonwoven fabric (SMS, SSMMS, etc.) is particularly suitable, and polypropylene, polyethylene/polypropylene composite material, etc. may be used as the material. It is desirable that a basis weight is <NUM> to <NUM>/m<NUM>, particularly <NUM> to <NUM>/m<NUM>.

A package mode of the package sheet <NUM> may be appropriately determined. However, from viewpoints of ease of manufacturing, prevention of leakage of the super absorbent polymer particle from front and back end edges, etc., in a preferable mode, winding is performed in a cylindrical shape to surround the front and back surfaces and both side surfaces of the absorbent body <NUM>, front and back edge portions thereof are allowed to protrude from the front and the back of the absorbent body <NUM>, and an overlapping portion of a winding portion and front and back protruding portions are bonded by bonding means such as a hot melt adhesive, material welding, etc..

The outer members 12F and 12B do not correspond to an integral outer member <NUM> that continues through the crotch from the front body F to the back body B illustrated in <FIG> and <FIG>, and includes the front side outer member 12F corresponding to a portion forming at least the lower torso portion of the front body F and the back side outer member 12B corresponding to a portion forming at least the lower torso portion of the back body B. The front side outer member 12F and the back side outer member 12B are not continuous on the crotch side and are spaced apart in the front-back direction LD. For example, a spaced distance 12d may be set to about <NUM> to <NUM>.

The outer members 12F and 12B have lower torso portions which are front-back direction zones corresponding to the lower torsos T. In addition, in this embodiment, the back side outer member 12B has a longer front-back direction dimension than that of the front side outer member 12F, the front side outer member 12F does not have a portion corresponding to the intermediate region L, and the back side outer member 12B has a gluteal cover portion C extending from the lower torsos T to the intermediate region L side. Although not illustrated, it is possible to adopt an embodiment in which an inguinal cover portion extending from the lower torso T to the intermediate region L side is provided in the front side outer member 12F, an inguinal cover portion is provided and the gluteal cover portion is not provided, or a part corresponding to the intermediate region L is not provided in both the front side outer member 12F and the back side outer member 12B. In addition, in the illustrated embodiment, a lower edge of the gluteal cover portion C is formed in a linear shape along the width direction WD similarly to the lower edge of the front side outer member 12F. However, the lower edge may be formed in a curved shape located on the waist opening side toward an outer side in the width direction.

A front-back direction dimension of a side edge of the gluteal cover portion C may be determined as appropriate. However, when the dimension is excessively long, a corner on the leg opening LO side of the side edge may flicker and the appearance and wearing feeling may deteriorate, and thus the dimension is preferably <NUM> or less.

As illustrated in <FIG> and <FIG>, the outer members 12F and 12B are obtained by bonding an outer sheet layer <NUM> and an inner sheet layer <NUM> located on an outside and an inside of elastic members <NUM> to <NUM> described below using bonding means such as the hot melt adhesive or welding. A sheet material forming the outer sheet layer <NUM> and a sheet material forming the inner sheet layer <NUM> may be formed of one common sheet material or separate sheet materials. That is, in the former case, the inner sheet layer <NUM> and the outer sheet layer <NUM> are formed by an inner portion and an outer portion of one sheet material, respectively, which is folded back at an edge of the waist opening WO (which may be a crotch side edge) in a part or a whole of the outer member. The former embodiment is advantageous in that the number of materials of the sheet material is small, and the latter embodiment is advantageous in that positional shift rarely occurs when the inner sheet layer <NUM> and the outer sheet layer <NUM> are bonded. The illustrated embodiment corresponds to the latter case, and the sheet material forming the inner sheet layer <NUM> extends only to the edge of the waist opening WO. However, the sheet material forming the outer sheet layer <NUM> wraps around the waist side edge of the sheet material of the inner sheet layer <NUM> and is folded back inside the sheet material, and this folded portion 12r extends to cover up to a waist side end portion of the inner member <NUM>.

As the sheet material used for the outer sheet layer <NUM> and the inner sheet layer <NUM>, any material may be used without particular restriction. However, a nonwoven fabric is preferably used. Examples thereof may include a synthetic fiber such as a polyolefin synthetic fiber such as polyethylene, polypropylene, etc., a polyester synthetic fiber, a polyamide synthetic fiber, etc., or a nonwoven fabric containing a mixed fiber, a composite fiber, etc. using two types or more thereof. Further, the nonwoven fabric may be manufactured by any process. Examples of a processing method may include a known method such as a spun lace method, a spun bond method, a thermal bond method, a melt blown method, a needle-punch method, an air-through method, a point bond method, etc. When the nonwoven fabric is used, a basis weight thereof is preferably set to about <NUM> to <NUM>/m<NUM>.

In addition, a total basis weight of the outer members 12F and 12B is preferably about <NUM> to <NUM>/m<NUM>.

In the outer members 12F and 12B, to enhance fitting to the periphery of the trunk of the wearer, the elastic members <NUM> to <NUM> are provided between the outer sheet layer <NUM> and the inner sheet layer <NUM>, and a stretchable region A2 that elastically stretches and contracts in the width direction WD in response to stretch and contraction of the elastic member is formed. In this stretchable region A2, in a natural length state, the outer sheet layer <NUM> and the inner sheet layer <NUM> contract in response to contraction of the elastic member, and wrinkles and pleats are formed. Stretch in a longitudinal direction of the elastic member allows stretch up to a predetermined stretch rate at which the outer sheet layer <NUM> and the inner sheet layer <NUM> fully extend without wrinkles. As the elastic members <NUM> to <NUM>, in addition to an elongated elastic member (not illustrated example) such as rubber thread, it is possible to use a known elastic member such as a belt-shaped, net-shaped, or film-shaped elastic member without particular limitation. Synthetic rubber or natural rubber may be used as the elastic members <NUM> to <NUM>.

For bonding of the outer sheet layer <NUM> and the inner sheet layer <NUM> in the outer members 12F and 12B and fixing of the elastic members <NUM> to <NUM> interposed therebetween, it is possible to use at least one of a hot melt adhesive based on various coating methods and fixing means based on material welding such as heat sealing, ultrasonic sealing, etc. Since flexibility deteriorates when the entire surfaces of the outer members 12F and 12B are firmly fixed, it is preferable that a portion other than bonded portions of the elastic members <NUM> to <NUM> is not bonded or is weakly bonded. In the illustrated embodiment, the hot melt adhesive is applied only to outer circumferential surfaces of the elastic members <NUM> to <NUM> by coating means such as a comb gun or a sure-wrap nozzle and the elastic members <NUM> to <NUM> are interposed between both the sheet layers <NUM> and <NUM>, thereby performing fixing of the elastic members <NUM> to <NUM> to both the sheet layers <NUM> and <NUM> and fixing between both the sheet layers <NUM> and <NUM> only by the hot melt adhesive applied to the outer circumferential surfaces of the elastic members <NUM> to <NUM>. The elastic members <NUM> to <NUM> can be fixed to the outer sheet layer <NUM> and the inner sheet layer <NUM> only at both end portions in an extending direction in the stretchable region.

The elastic members <NUM> to <NUM> of the illustrated embodiment will be described in more detail. Between the outer sheet layer <NUM> and the inner sheet layer <NUM> in the waist portion W of the outer members 12F and 12B, a plurality of waist portion elastic members <NUM> are attached at intervals in the front-back direction to be continuous over a whole in the width direction WD. In addition, one or a plurality of waist portion elastic members among the waist portion elastic members <NUM> arranged in a region adjacent to the lower waist portion U may overlap the inner member <NUM> or may be provided on both sides of a width direction center portion overlapping the inner member <NUM> in the width direction except for the width direction center portion. As the waist portion elastic members <NUM>, it is preferable to provide about three to twenty two rubber threads having a fineness of about <NUM> to <NUM>,<NUM> dtex, particularly <NUM> to <NUM>,<NUM> dtex (in the case of synthetic rubber. In the case of natural rubber, a cross-sectional area is about <NUM> to <NUM><NUM>, particularly <NUM> to <NUM><NUM>) at an interval of <NUM> to <NUM>, and it is preferable that a stretch rate of the waist portion W in the width direction WD resulting therefrom is about <NUM> to <NUM>%, particularly <NUM> to <NUM>%. In addition, it is unnecessary to use the waist portion elastic members <NUM> having the same fineness or set the same stretch rate in the whole waist portion W in the front-back direction LD. For example, the fineness or the stretch rate of the waist portion elastic members <NUM> may be different between an upper part and a lower part of the waist portion W.

In addition, a plurality of lower waist portion elastic members <NUM> and <NUM> formed of an elongated elastic member is attached at an interval in the front-back direction between the outer sheet layer <NUM> and the inner sheet layer <NUM> in the lower waist portion U of the outer members 12F and 12B.

As the lower waist portion elastic members <NUM> and <NUM>, it is preferable to provide about five to thirty rubber threads having a fineness of about <NUM> to <NUM>,<NUM> dtex, particularly <NUM> to <NUM>,<NUM> dtex (in the case of synthetic rubber. In the case of natural rubber, a cross-sectional area is about <NUM> to <NUM><NUM>, particularly <NUM> to <NUM><NUM>) at an interval of <NUM> to <NUM>, particularly <NUM> to <NUM>, and it is preferable that a stretch rate of the lower waist portion U in the width direction WD resulting therefrom is about <NUM> to <NUM>%, particularly <NUM> to <NUM>%.

In addition, a cover portion elastic member <NUM> formed of an elongated elastic member is attached between the outer sheet layer <NUM> and the inner sheet layer <NUM> in the gluteal cover portion C of the back side outer member 12B.

As the cover portion elastic member <NUM>, it is preferable to provide one or a plurality of rubber threads having a fineness of about <NUM> to <NUM>,<NUM> dtex, particularly <NUM> to <NUM>,<NUM> dtex (in the case of synthetic rubber. In the case of natural rubber, a cross-sectional area is about <NUM> to <NUM><NUM>, particularly <NUM> to <NUM><NUM>) with intervals in the front-back direction, and it is preferable that a stretch rate of the gluteal cover portion C in the width direction WD resulting therefrom is about <NUM> to <NUM>%, particularly <NUM> to <NUM>%.

In the case of providing the cover portion elastic member <NUM>, it is preferable that a front-back direction interval between the cover portion elastic member <NUM> located closest to the leg opening LO side at a side edge Cs of the gluteal cover portion C and a leg opening side edge Ce of the gluteal cover portion C is <NUM> to <NUM> times a width direction dimension W3 from a side edge of the back side outer member 12B to a side edge of the side seal portions 12A on a center side in the width direction, because a corner of the side edge Cs of the gluteal cover portion C on a side of the leg openings LO is almost inconspicuous. In particular, in this case, it is preferable to provide one cover portion elastic member <NUM> or two cover portion elastic members <NUM> at an interval of <NUM> or less in the front-back direction LD. In addition, it is preferable that a front-back direction interval from the cover portion elastic member <NUM> located closest to the waist side to the lower waist portion elastic member <NUM> adjacent to the waist side is <NUM> or more and widest among intervals of all elastic members in the back side outer member 12B, because a portion on the waist side of the cover portion elastic member <NUM> appears to be wider than a portion on the leg opening side of the cover portion elastic member <NUM> in the back side outer member 12B, so that protrusion of the corner on the leg opening LO side of the side edge Cs of the gluteal cover portion C becomes less conspicuous.

Here, if the cover portion elastic member <NUM> is disposed only on the leg opening LO side in the gluteal cover portion C, when the gluteal cover portion C contracts together with the cover portion elastic member <NUM> as illustrated in <FIG>, the leg opening LO side of the gluteal cover portion C is drawn to the center side in the width direction WD. Thus, even when the edge Ce of the gluteal cover portion C on the leg opening LO side is linear along the width direction WD, the edge Ce of the gluteal cover portion C on the leg opening LO side diagonally inclines downward toward the center side in the width direction WD, and fitting with respect to a gluteal fold is improved. In this instance, the side edge Cs of the gluteal cover portion C diagonally inclines downward toward the center side in the width direction WD so that the corner of the side edge Cs of the gluteal cover portion C on the leg opening LO side is inconspicuous and the appearance does not deteriorate.

Meanwhile, in a case in which the cover portion elastic member <NUM> is disposed only on the waist side in the gluteal cover portion C, when the gluteal cover portion C contracts together with the cover portion elastic member <NUM> as illustrated in <FIG>, the waist side of the gluteal cover portion C is drawn to the center side in the width direction. Thus, even when the edge Ce of the gluteal cover portion C on the leg opening LO side is linear along the width direction WD, the side edge Cs of the gluteal cover portion C warps backward to a side, the edge Ce of the gluteal cover portion C on the leg opening LO side diagonally inclines downward toward the center side in the width direction, and fitting with respect to the gluteal fold is improved. In this instance, even though the side edge Cs of the gluteal cover portion C warps backward to the side, the corner of the side edge Cs of the gluteal cover portion C on the leg opening LO side does not greatly protrude to the side of the side seal portions 12A. Thus, the corner of the side edge Cs of the gluteal cover portion C on the leg opening LO side is inconspicuous, and the appearance does not deteriorate.

In addition, in a case in which a front-back direction dimension at the side edge Cs of the gluteal cover portion C is <NUM> to <NUM> times a width direction dimension W3 from the side edge of the back side outer member 12B to the side edge of the center side of the side seal portions 12A in the width direction WD, the cover portion elastic member <NUM> of the gluteal cover portion C may not be provided. In this case, even though the side edge Cs of the gluteal cover portion C easily warps backward to the side due to an influence of contraction of the lower waist portion by the lower waist portion elastic member <NUM>, the corner of the side edge Cs of the gluteal cover portion C on the leg opening LO side rarely protrudes from the side edge of the diaper. Thus, this corner is inconspicuous, and the appearance does not deteriorate.

When the inguinal cover portion is provided in the front side outer member 12F, the cover portion elastic member may be similarly provided.

The elastic members <NUM>, <NUM>, and <NUM> are provided in the front-back direction zones having the absorbent body <NUM> as in the lower waist portion U or the gluteal cover portion C of the illustrated embodiment, wherein a middle portion in the width direction including a part or a whole of a portion overlapping the absorbent body <NUM> in the width direction WD (preferably including the entire inner and outer joined portions <NUM> and <NUM>) is set as a non-stretchable region A1, and both sides thereof in the width direction are set as a stretchable region A2 to prevent contraction of the absorbent body <NUM> in the width direction WD in a part or a whole thereof. The waist portion W is preferably set as the stretchable region A2 over the whole in the width direction WD. However, similarly to the lower waist portion U, the non-stretchable region A1 may be provided in the middle in the width direction.

The stretchable region A2 and the non-stretchable region A1 can be constructed by supplying the elastic members <NUM> to <NUM> and <NUM> between the inner sheet layer <NUM> and the outer sheet layer <NUM>, fixing the elastic members <NUM>, <NUM>, and <NUM> at least at both end portions of the stretchable region A2 in the extending direction through the hot melt adhesive, not fixing the elastic members <NUM>, <NUM>, and <NUM> in a region corresponding to the non-stretchable region A1, and cutting the elastic members <NUM>, <NUM>, and <NUM> at one place in the middle in the width direction by pressing and heating or finely cutting almost all of the elastic members <NUM>, <NUM>, and <NUM> by pressing and heating in the region corresponding to the non-stretchable region A1, thereby killing elasticity in the non-stretchable region A1 while leaving elasticity in the stretchable region A2. In the former case, as illustrated in <FIG>, in the non-stretchable region A1, a remaining cut portion continuing from the elastic members <NUM>, <NUM>, and <NUM> of the stretchable region A2 is left between the outer sheet layer <NUM> and the inner sheet layer <NUM> in a state of contracting to a natural length as an unnecessary elastic member <NUM> alone. In the latter case, although not illustrated, the remaining cut portion continuing from the elastic members <NUM>, <NUM>, and <NUM> of the stretchable region A2 and a cut piece of the elastic member not continuing from the elastic members <NUM>, <NUM>, and <NUM> of both the stretchable region A2 are left between the outer sheet layer <NUM> and the inner sheet layer <NUM> in a state of contracting to a natural length as an unnecessary elastic member alone.

As illustrated in <FIG>, <FIG>, <FIG>, and <FIG>, a display sheet <NUM> having a display <NUM> of a character, etc. is interposed between at least one of the front side outer member 12F and the back side outer member 12B and the inner member <NUM>, and a display of the display sheet <NUM> is seen through the outer members 12F and 12B. In the case of a mode in which the display sheet <NUM> is interposed between the outer members 12F and 12B and the inner member <NUM>, a process of cutting the elastic members <NUM>, <NUM>, and <NUM> for forming the non-stretchable region A1 can be performed without the display sheet <NUM> at the time of manufacture. Thus, a trace of cutting is not left on the display sheet <NUM>, and deterioration of the appearance can be prevented.

A resin film is used as a material of the display sheet <NUM> in terms of being suitable for high-definition printing. In the case of using a resin film having high opacity, a printed part needs to be provided on an external surface of the display sheet <NUM>. However, for example, in the case of using a resin film having high transparency, a printed part may be provided on an internal surface of the display sheet <NUM>.

The display <NUM> applied to the display sheet <NUM> is not particularly limited, and it is possible to apply a display such as a pattern (including a picture and a one-point character) for decoration, a function display such as a usage method, assistance for use, a size, etc., or a mark indication such as a manufacturer, a product name, a distinctive function, etc. by printing, etc..

At least one of the internal surface and the external surface of the display sheet <NUM> is bonded to a facing surface by a hot melt adhesive <NUM>.

A dimension of the display sheet <NUM> may be appropriately determined. However, in a normal case, it is preferable that the display sheet <NUM> is provided to be smaller than or equal to a width of the inner member <NUM> within a width direction range overlapping the inner member <NUM>. Specifically, when the display sheet <NUM> is <NUM> to <NUM>% of the width of the inner member <NUM>, it is easy to stick to the inner member <NUM> side at the time of manufacture, which is preferable. In addition, it is preferable that a width 25x of the display sheet <NUM> is wider than a width 13x of the cover nonwoven fabric <NUM> described below.

The display sheet <NUM> may be disposed within a range overlapping the inner member <NUM> as the display sheet <NUM> disposed in the back body B illustrated in the figure. At least one display sheet <NUM> is made of a liquid impervious resin film. When the display sheet <NUM> extends from the region overlapping the inner member <NUM> to an inside of a waist extended section 12E extending to the waist opening WO side of the waist side edge of the inner member <NUM> as the display sheet <NUM> disposed in the front body F illustrated in the figure, it is possible to prevent seepage of urine and loose stools in the waist extended section 12E of the front side outer member 12F by blocking urine and loose stools leaking from the waist side end portion of the inner member <NUM> to the waist side using the display sheet <NUM>. Unlike the illustrated embodiment, together with or in place of the display sheet <NUM> of the front body F, the display sheet <NUM> disposed in the back body B can be extended from the region overlapping the inner member <NUM> to an inside of the waist extended section 12E. As the liquid impervious resin film, it is possible to select the same material as that of the liquid impervious sheet <NUM>. In particular, it is preferable to use a plastic film having moisture permeability similarly to the liquid impervious sheet <NUM>.

When the display sheet <NUM> is extended to the inside of the waist extended section 12E, it is more preferable that an elastic member that contracts a width direction range corresponding to at least an intermediate part of the display sheet <NUM> in the width direction is provided at a position spaced <NUM> or more apart to the waist opening WO side from the waist side edge of the inner member <NUM> in the waist extended section 12E. In the illustrated embodiment, the waist portion elastic member <NUM> corresponds to the elastic member of this arrangement. While a region in which the outer members 12F and 12B overlap the inner member <NUM> has high rigidity and rarely bends, the waist extended section 12E has low rigidity and easily bends. Thus, as illustrated in <FIG>, when the display sheet <NUM> contracts in the width direction toward the waist side by the waist portion elastic member <NUM>, and a portion between the elastic member and the inner member <NUM> in the waist extended section 12E bends toward the skin side at a boundary with the inner member <NUM>, a portion of the waist extended section 12E having the display sheet <NUM> rises, and a blocking wall for urine and loose stools is formed. Therefore, it is possible to improve prevention of seepage of urine and loose stools in the waist extended section 12E of the outer members 12F and 12B. In this case, it is preferable that the waist extended section 12E only includes a nonwoven fabric that forms the outer sheet layer <NUM> and the inner sheet layer <NUM>, because a difference in rigidity between the region in which the outer members 12F and 12B overlap the inner member <NUM> and the waist extended section 12E increases. In addition, as the number of overlapping sheets at a waist side edge portion of the inner member <NUM> increases, the difference in rigidity increases, which is preferable. Specifically, it is preferable to have three or more number difference. In particular, when at least the liquid impervious sheet <NUM> including the plastic film is present or the package sheet <NUM> including crepe paper is further present at the waist side edge portion of the inner member <NUM>, rigidity increases, which is preferable. In addition, it is preferable that the bulky intermediate sheet <NUM> extends to the waist side edge portion of the inner member <NUM>. It is preferable that the region in which the outer members 12F and 12B overlap the inner member <NUM> coincides with the non-stretchable region A1 so that the region does not bend.

A front-back direction length 25y of that portion of the display sheet <NUM> which is located in the waist extended section 12E is not particularly limited. However, in a normal case, the length is preferably <NUM> or more. In addition, when the display sheet <NUM> extends to at least an elastic member located closest to the inner member <NUM> side (in the illustrated embodiment, a member located closest to the crotch side among the waist portion elastic members <NUM>), it is particularly preferable for improving prevention of seepage of urine and loose stools in the waist extended section 12E of the outer members 12F and 12B.

In the outer member separated type underpants-type disposable diaper, the inner member <NUM> is exposed between the front side outer member 12F and the back side outer member 12B, and thus the disposable diaper includes the cover nonwoven fabric <NUM> that covers the back surface of the inner member <NUM> from between the front side outer member 12F and the inner member <NUM> to between the back side outer member 12B and the inner member <NUM> so that the liquid impervious sheet <NUM> is not exposed to the back surface of the inner member <NUM>.

Characteristically, the cover nonwoven fabric <NUM> is a perforated nonwoven fabric in which a large number of holes <NUM> penetrating the front and back are provided at intervals, and extends in the front-back direction LD to have a portion located between the display sheet <NUM> and the liquid impervious sheet <NUM>. When the cover nonwoven fabric <NUM> extends to a space between the display sheet <NUM> and the liquid impervious sheet <NUM> as described above, ventilation is allowed through the nonwoven fabric with the holes <NUM> from the outside of the disposable diaper to the space between the display sheet <NUM> and the liquid impervious sheet <NUM>, and thus it is possible to prevent deterioration of the air permeability when the resin film is used as the material of the display sheet <NUM>.

Although not illustrated, at least, a perforated nonwoven fabric dedicated for improving air permeability may be provided separately from the cover nonwoven fabric <NUM>. The perforated nonwoven fabric extends from a crotch side edge of the outer members 12F and 12B overlapping the display sheet <NUM> to a space between the display sheet <NUM> and the liquid impervious sheet <NUM> on the waist opening side. In addition, in the case of having the display sheet <NUM> on both the front and the back, the cover nonwoven fabric <NUM> may merely extend to a space between the display sheet <NUM> and the liquid impervious sheet <NUM> in only either one of the front side outer member 12F and the back side outer member 12B.

There are no particular restrictions on the type of fibers of the perforated nonwoven fabric and a processing method for bonding (entanglement) of the fibers, and the same materials as the materials for the outer members 12F and 12B can be appropriately selected. However, it is desirable to use an air-through nonwoven fabric. In this case, it is preferable that a basis weight is <NUM> to <NUM>/m<NUM> and a thickness is <NUM> to <NUM>.

The front-back direction zones of the cover nonwoven fabric <NUM> are not particularly limited as long as the front-back direction zones have a portion located between the display sheet <NUM> and the liquid impervious sheet <NUM>. The front-back direction zones may extend in the front-back direction LD over a whole area from a front end to a back end of the inner member <NUM> as illustrated in <FIG>, <FIG>, and <FIG>, and may extend in the front-back direction LD from a middle position in the front-back direction in a region overlapping the front side outer member 12F and the inner member <NUM> to a middle position in the front-back direction in a region overlapping the back side outer member 12B and the inner member <NUM> as illustrated in <FIG>. A front-back direction length 25w of an overlapping portion of the display sheet <NUM> and the cover nonwoven fabric <NUM> is preferably <NUM> to <NUM>% of a front-back direction length 25y of the display sheet <NUM>. In addition, in the case of an embodiment illustrated in <FIG>, a front-back direction length 13y of an overlapping portion of the cover nonwoven fabric <NUM> and the front side outer member 12F and a front-back direction length 13y of an overlapping portion of the cover nonwoven fabric <NUM> and the back side outer member 12B may be determined as appropriate. However, in a normal case, each of the lengths may be set to about <NUM> to <NUM>.

A width direction range of the cover nonwoven fabric <NUM> is set to a range in which an exposed portion of the back surface of the liquid impervious sheet <NUM> can be concealed. For this reason, in the illustrated embodiment, the liquid impervious sheet <NUM> is exposed between bases of the left and right side gathers <NUM>, and thus the cover nonwoven fabric <NUM> is provided to cover at least a width direction range from the back surface side of the base portion of one of the side gathers <NUM> to the back surface side of the base portion of the other one of the side gathers <NUM>. In this way, the liquid impervious sheet <NUM> can be concealed by the cover nonwoven fabric <NUM> and the gather nonwoven fabric <NUM> of the side gather <NUM>, and the holes <NUM> in both end portions of the cover nonwoven fabric <NUM> in the width direction are not concealed by the gather nonwoven fabric <NUM> when viewed from the external surface. In addition, when the side edge of the cover nonwoven fabric <NUM> is the same as a side edge of a portion of the absorbent body <NUM> having a narrowest width (a maximum width in the case of not having the narrower portion 56N. a portion having a narrowest width in the narrower portion 56N in the case of having the narrower portion 56N) or is located on a center side thereof in the width direction, the cover nonwoven fabric <NUM> is located only in a portion in which the entire cover nonwoven fabric <NUM> overlaps the absorbent body <NUM>, that is, a portion in which rigidity is high and wrinkles and folds are rarely generated. Thus, both side portions of the cover nonwoven fabric <NUM> rarely contracts in the front-back direction LD. Further, wrinkles are rarely formed and crushing of the holes <NUM> rarely occurs in both side portions of the cover nonwoven fabric <NUM>. In addition, even when the both end portions of the cover nonwoven fabric <NUM> in the width direction do not cover the back surface side of the base portion of the side gather <NUM>, and the gather nonwoven fabric <NUM> covers the back surface side of the both end portions of the cover nonwoven fabric <NUM> in the width direction, the liquid impervious sheet <NUM> can be concealed by the cover nonwoven fabric <NUM> and the gather nonwoven fabric <NUM>. In this case, the both end portions of the cover nonwoven fabric <NUM> are covered with the gather nonwoven fabric <NUM>, and thus there is an advantage that the both side portions of the cover nonwoven fabric <NUM> are hardly peeled off from the liquid impervious sheet <NUM>.

As long as the holes <NUM> are formed in at least a portion overlapping the display sheet <NUM> in the front-back direction, the cover nonwoven fabric <NUM> may have a region not including the holes <NUM> in a part in the front-back direction LD. However, it is desirable to provide the holes <NUM> in the whole area in the front-back direction in consideration of the effect of improving the air permeability. Meanwhile, in a mode in which a region not having the holes <NUM> is included in the both end portions of the cover nonwoven fabric <NUM> in the width direction WD, when the holes <NUM> are formed by a method other than punching using a cutter, a fiber of a peripheral portion 14e of the hole <NUM> is retracted to the outside or in a vertical direction as described below to warp the peripheral portion 14e of the hole <NUM>, and a perforated region becomes thicker than a nonporous region. Thus, when the material of the cover nonwoven fabric <NUM> is stored in a rolled state, a part of the nonporous region is loosely wound, and there is concern that wrinkles and folds may be formed in the nonporous region of the both side portions. Therefore, it is desirable that the holes <NUM> be formed throughout the whole in the width direction WD as in the illustrated embodiment. When holes are formed in the cover nonwoven fabric <NUM> in a manufacturing process of the diaper, a material having no holes can be used, and a hole formation site may be arbitrarily controlled. However, there are problems that introduction of hole forming equipment increases overall manufacturing, which increases burden of cost and maintenance, and adjustment of a hole shape and softness becomes difficult in a high speed line. Therefore, it is preferable to perform manufacture using a material in which holes are formed throughout the whole in the front-back direction and the width direction.

A planar shape (opening shape) of each of the holes <NUM> may be appropriately determined. In addition to an elongated hole shape illustrated in <FIG>, it is possible to adopt an arbitrary shape such as a perfect circle illustrated in <FIG>, an ellipse illustrated in <FIG>, a polygon such as a triangle, a rectangle, a rhombus, etc., a star shape, a cloud shape, etc. Dimensions of each hole <NUM> are not particularly limited. However, it is preferable that a maximum dimension <NUM> in the front-back direction LD is set to <NUM> to <NUM>, particularly <NUM> to <NUM>, and it is preferable that a maximum dimension 14W in the width direction WD is set to <NUM> to <NUM>, particularly <NUM> to <NUM>. In a case in which the shape of the hole <NUM> is long in one direction as the elongated hole shape, the ellipse, the rectangle, the rhombus, etc., a maximum dimension in a longitudinal direction is preferably <NUM> times or less a maximum dimension in a direction orthogonal thereto. In addition, in a case in which the shape of the hole <NUM> is long in one direction, it is desirable that the longitudinal direction of the hole <NUM> corresponds to the front-back direction LD. However, the longitudinal direction may correspond to the width direction WD or an oblique direction.

An area and an area ratio of each hole <NUM> may be appropriately determined. However, the area is preferably about <NUM> to <NUM><NUM> (particularly <NUM> to <NUM><NUM>), and the area ratio is preferably about <NUM> to <NUM>% (particularly <NUM> to <NUM>%).

A plane arrangement of the holes <NUM> can be determined as appropriate. However, a plane arrangement having regular repetition is preferable, and it is possible to adopt an arrangement in which a group of holes <NUM> (a group-based arrangement may be regular or irregular and may correspond to a pattern, letter shape, etc.) is regularly repeated in addition to an arrangement having regular repetition such as a rhombic lattice shape illustrated in <FIG>, a hexagonal lattice shape illustrated in <FIG> (these shapes are also referred to as a staggered shape), a square lattice shape illustrated in <FIG>, a rectangular lattice shape illustrated in <FIG>, or a parallel body lattice illustrated in <FIG> (as illustrated in the figure, a mode in which two groups are provided such that groups of a large number of parallel and oblique columns intersect with each other) (including those inclined at an angle of less than <NUM> degrees with respect to the front-back direction LD).

A front-back direction interval 14y and a width direction interval 14x of the holes <NUM> may be appropriately determined. However, considering air permeability, it is desirable that each of the intervals is within a range of <NUM> to <NUM>, particularly <NUM> to <NUM>, and it is preferable that the front-back direction interval 14y and the width direction interval 14x are averaged to be in a range of <NUM> to <NUM>. In particular, as illustrated in <FIG>, when the shape of the hole <NUM> is set to an elongated shape in the front-back direction LD, a column of holes <NUM> lined up in the front-back direction at the front-back direction interval 14y narrower than the maximum dimension <NUM> of the hole <NUM> in the front-back direction LD is repeated at a predetermined interval in the width direction WD, and the width direction interval 14x thereof is wider than the maximum dimension <NUM> of the hole <NUM> in the front-back direction LD (more preferably <NUM> times or more the width direction dimension 14W of the hole <NUM>), it is preferable since softness and bulkiness are not impaired while remarkably improving air permeability, and tensile strength of the sheet in the front-back direction, which is important in manufacturing, does not decrease.

As a cross-sectional shape of the hole <NUM>, it is possible to adopt any one of a first embodiment in which the thickness of the nonwoven fabric decreases from a periphery of the hole <NUM> toward an edge of the hole <NUM>, and the edge of the hole <NUM> is located in the middle of the nonwoven fabric in the thickness direction as illustrated in <FIG>, a second embodiment in which the peripheral portion 14e of the hole <NUM> is warped to the front surface side, and a warping height <NUM> is substantially uniform as illustrated in <FIG>, and a third embodiment in which the peripheral portion 14e of the hole <NUM> is warped to the front surface side, and the peripheral portion 14e has a facing portions in which a warping height 14i is the highest and facing portions facing in a direction orthogonal thereto in which a warping height 14j is the lowest as illustrated in <FIG>. From the viewpoint of air permeability, the second embodiment and the third embodiment in which a portion having the holes <NUM> is thicker than the surroundings are desirable. In particular, the third embodiment is preferable since a gap formed by a difference between the warping heights 14i and 14j of the peripheral portion 14e of the hole <NUM> contributes to improvement in air permeability. In the second and third embodiments, the warping heights <NUM>, <NUM>, and 14i (apparent heights measured using an optical microscope in a state no pressure is applied) are preferably about <NUM> to <NUM>. In the third embodiment, the highest warping height 14i is preferably about <NUM> to <NUM> times the lowest warping height 14j.

The hole <NUM> may correspond to a punched hole whose edge portion is formed of a cut end of a fiber or a non-punched hole (having a high fiber density in a peripheral portion) in which almost no cut end of a fiber is present at the edge portion of the hole <NUM> and which is formed by inserting and spreading out a pin between fibers. The former is suitable for the first embodiment, and the latter is suitable for the second embodiment and the third embodiment. For example, when the hole <NUM> having an elongated shape in one direction is formed by inserting a pin, a fiber of the peripheral portion 14e of the hole <NUM> is retracted to the outside or in the vertical direction so that the peripheral portion 14e of the hole <NUM> warps, and the warping height i of the facing portion of the hole <NUM> in the longitudinal direction becomes higher than the warping height j of the facing portion in the direction orthogonal to the longitudinal direction. In the second embodiment and the third embodiment, the edge portion of the portion in which the peripheral portion 14e of the hole <NUM> is warped to the surface has a lower fiber density than that of the surrounding portion in some cases. However, the fiber density is preferably the same or higher. In addition, it is desirable that fibers of the peripheral portion 14e of the hole <NUM> are fused to each other and may not be fused to each other.

Each of the internal surface and the external surface of the cover nonwoven fabric <NUM> is bonded to a facing surface by the hot melt adhesive. A fixed region of the cover nonwoven fabric <NUM> may be set to the whole in the front-back direction and the whole in the width direction of the cover nonwoven fabric <NUM>, or a part may not be fixed. For example, if both end portions of the cover nonwoven fabric <NUM> in the width direction are not fixed, even when side portions of the absorbent body <NUM> are somewhat contracted due to an influence of the side gathers <NUM>, this contraction have little effect, and wrinkles and folds are rarely formed in the cover nonwoven fabric <NUM>, which is advantageous. A width of a non-fixing part of the both end portions of the cover nonwoven fabric <NUM> in the width direction in this case may be appropriately determined. For example, the width may be set to <NUM> to <NUM>, preferably <NUM> to <NUM>.

In one preferable bonding structure, as illustrated in <FIG>, in a bonded region of at least one of the internal surface and the external surface of the cover nonwoven fabric <NUM>, a hot melt adhesive <NUM> is not present on a center side of a peripheral edge portion 14i of a region overlapping the hole <NUM>, and the hot melt adhesive <NUM> is applied in a continuous surface shape in a portion other than the peripheral edge portion 14i of the region overlapping the hole <NUM>. Since the hot melt adhesive <NUM> is not present on the center side of the peripheral edge portion 14i of the region overlapping the hole <NUM>, air permeability is excellent. In addition, in a portion having such a bonding structure only on a surface opposite from a surface to be touched by the skin, a sticky texture due to the hot melt adhesive <NUM> is rarely obtained, and the peripheral portion 14e of the hole <NUM> is reliably fixed to the facing surface.

Examples of a typical bonding state may include a state in which the hot melt adhesive <NUM> is not present in the region overlapping the hole <NUM>, and the hot melt adhesive <NUM> is applied in a continuous surface shape in a region other than the region overlapping the hole <NUM> as illustrated in <FIG>, and a state in which the hot melt adhesive <NUM> protrudes to the peripheral edge portion 14i of the region overlapping the hole <NUM>, the hot melt adhesive <NUM> is not present on the center side of the peripheral edge portion 14i of the region overlapping the hole <NUM>, and the hot melt adhesive <NUM> is applied in a continuous surface shape in the portion other than the peripheral edge portion 14i of the region overlapping the hole <NUM> as illustrated in <FIG>. The former state is a particularly desirable state. Since the peripheral edge portion 14i of the region overlapping the hole <NUM> is a portion close to the peripheral portion 14e of the hole <NUM>, and the cover nonwoven fabric <NUM> has a constant thickness, even when the hot melt adhesive <NUM> protrudes to this portion as in the latter, the hot melt adhesive <NUM> is rarely directly touched at the time of touching the surface on the opposite side from a bonded surface in the cover nonwoven fabric <NUM> with a hand in the portion in which only the surface on the opposite side from the surface touching the skin is bonded. A protruding width of the hot melt adhesive <NUM> in the peripheral edge portion 14i of the region overlapping with the hole <NUM> is less than or equal to a half of the thickness of the cover nonwoven fabric <NUM> and preferably about <NUM> or less. In addition, it is desirable that the hot melt adhesive <NUM> is not present in a portion of <NUM>% or more of the area of the region overlapping the hole <NUM>.

The cross-sectional shape of the hole <NUM> in the cover nonwoven fabric <NUM> is not limited. However, when the peripheral portion 14e of the hole <NUM> corresponds to the warped portion warped to the liquid impervious sheet <NUM> side as described above, a hole diameter viewed from the liquid impervious sheet <NUM> side becomes smaller than a hole diameter viewed from a surface on the opposite side from the liquid impervious sheet <NUM> side. Therefore, in a portion in which only the surface on the opposite side from the surface touching the skin is bonded, the hot melt adhesive <NUM> is rarely directly touched at the time of touching the surface on the opposite side from the bonded surface with the hand. In addition, the warped portion supports the cover nonwoven fabric <NUM> with respect to the facing surface as a post, and thus is bulky and excellent in air permeability when compared to a non-porous nonwoven fabric having the same basis weight. Further, in a region other than the peripheral portion 14e of the hole <NUM>, bonding of the cover nonwoven fabric <NUM> and the liquid impervious sheet <NUM> is likely to float (even though the hot melt adhesive <NUM> fills a space between sheets without any gap in <FIG>, an actual coating amount is small, and a gap is liable to be formed), and thus the peripheral portion 14e of the hole <NUM> is reliably bonded while bonding is incomplete in other regions (an actual bonded area becomes small). In this way, it is possible to obtain excellent softness/fullness.

Such a bonding structure can be produced by applying the hot melt adhesive to the bonding surface in the perforated nonwoven fabric in a continuous surface shape without using air, and bonding facing surfaces. This scheme is based on a new finding in which when the hot melt adhesive is applied to the bonding surface in the perforated nonwoven fabric in a continuous surface shape without using air, an opening (hole) h is formed at a center of a portion overlapping a hole of the perforated nonwoven fabric in the hot melt adhesive due to surface tension of the hot melt adhesive before bonding to the facing surface, and the opening widens to the peripheral portion of the hole of the perforated nonwoven fabric. That is, when such a bonding scheme is adopted, an opening (hole) is formed at a center of a portion overlapping the hole <NUM> of the perforated nonwoven fabric in the hot melt adhesive <NUM> due to surface tension of the hot melt adhesive <NUM> before bonding to a target member and after the hot melt adhesive <NUM> is applied to the perforated nonwoven fabric in a continuous surface shape as illustrating changes using arrows in <FIG>, and the opening h widens to the peripheral portion 14e of the hole <NUM> of the perforated nonwoven fabric. Therefore, after the perforated nonwoven fabric is bonded to the target member, the hot melt adhesive <NUM> is not present in a most part of the hole <NUM> as in an example illustrated in <FIG>, and the hot melt adhesive <NUM> does not escape or exude from the hole <NUM> by air. Thus, the sticky texture is rarely obtained when the surface on the opposite side from the bonded surface is touched with hand.

As a hot melt applicator that applies the hot melt adhesive in a continuous surface shape without using air, it is possible to suitably use slot coat that brings a coating head (die) into contact with the bonding surface of the perforated nonwoven fabric and extrudes the hot melt adhesive from a slit extending along a cross direction (CD) (a direction orthogonal to a machine direction (MD) (a flow direction of a production line)) provided at a tip of the coating head to perform coating, or non-contact type slot coat that extrudes the hot melt adhesive from the slit extending along the CD provided at the tip of the coating head in a state in which the coating head (die) floats from the bonded surface of the perforated nonwoven fabric, and stretches and applies the hot melt adhesive in a form of an extremely thin film by a difference with a transporting speed of the perforated nonwoven fabric.

Bonding conditions may be appropriately determined. However, to promptly move the hot melt adhesive <NUM> overlapping the hole <NUM> to the peripheral portion 14e of the hole <NUM>, and firmly bond the peripheral portion 14e of the hole <NUM>, it is desirable to satisfy at least one of the following conditions.

In another preferable bonding structure, as illustrated in <FIG>, the peripheral portion 14e of the hole <NUM> in the cover nonwoven fabric <NUM> corresponds to a warped portion which is warped, at least the tip portion of the warped portion corresponds to a bonded portion stuck to the facing surface (in this case, the liquid impervious sheet <NUM>) by the hot melt adhesive <NUM>, and a portion other than this bonded portion is not bonded. When such a bonding structure is adopted, the bonded area decreases, and thus flexibility is not impaired, and the peripheral portion 14e of the hole <NUM> is reliably fixed to the facing surface. In particular, the warped portion supports the cover nonwoven fabric <NUM> with respect to the facing surface as a post, and thus is bulky and excellent in air permeability when compared to a non-porous nonwoven fabric having the same basis weight.

Examples of a typical bonding state may include a state in which only the tip portion of the warped portion is bonded to the facing surface by the hot melt adhesive <NUM> as illustrated in <FIG>, a state in which the entire warped portion is bonded to the facing surface by the hot melt adhesive <NUM> as illustrated in <FIG>, and a state in which an entire outside of an internal portion of the tip portion in the warped portion is bonded to the facing surface by the hot melt adhesive <NUM> and the internal portion of the tip portion is not bonded as illustrated in <FIG>. Even though it is desirable that no adhesive is present on an inner peripheral surface of the hole <NUM> of the warped portion and the site of the facing surface overlapping the hole <NUM>, an adhesive may somewhat protrude.

A bonding state of the warped portion is not limited to the illustrated embodiment as long as at least the tip portion is stuck to the facing surface by the hot melt adhesive <NUM>, and at least a part of the hole <NUM> in a circumferential direction may corresponding to any one of the above bonding states. For example, as in the embodiment illustrated in <FIG> and <FIG>, when the warped portion has a cylindrical shape continuously in the circumferential direction of the hole <NUM>, the entire tip portion of the cylindrical shape in the circumferential direction is preferably in a bonding state. However, a part thereof may be in another bonding state or may not be bonded. In addition, when the warped portion is formed only in a part of the hole <NUM> in the circumferential direction, it suffices that a tip portion of the part is in the bonding state. Further, different bonding states may coexist in a large number of warped portions.

The inner member <NUM> may be fixed to the outer members 12F and 12B by bonding means based on material welding such as heat sealing or ultrasonic sealing or a hot melt adhesive. In the illustrated embodiment, the inner member <NUM> is fixed to the internal surfaces of the outer members 12F and 12B through the back surface of the inner member <NUM>, that is, the back surface of the liquid impervious sheet <NUM> in this case, and the hot melt adhesive applied to the root portion <NUM> of the side gather <NUM>. The inner and outer joined portions <NUM> and <NUM> that fix the inner member <NUM> and the outer members 12F and 12B to each other may be provided almost entirely in a region in which the members overlap with each other, and may be provided, for example, in a portion excluding both end portions of the inner member <NUM> in the width direction. In particular, when the inner and outer joined portions <NUM> and <NUM> are provided over a region overlapping the cover nonwoven fabric <NUM> and a region on both width sides of this region, it is possible to firmly fix the both side portions of the cover nonwoven fabric <NUM>, and the both side portions of the cover nonwoven fabric <NUM> are less likely to be peeled off from the inner member <NUM>, which is preferable.

As illustrated in <FIG> and <FIG>, it is preferable that the inner and outer joined portion <NUM> of the front side outer member 12F is provided to extend over both end portions in the width direction on the waist side, a width thereof decreases stepwise or continuously toward a crotch-side edge of the front side outer member 12F, and a non-joined part <NUM> is formed on both end portions of the crotch side of the front side outer member 12F in the width direction. In this way, even in an outer member separated type in which the crotch-side edge of the front side outer member 12F intersects the side edge of the inner member <NUM> at the right angle or an angle close thereto in a linear shape along the width direction or a shape close thereto, fitting of the inguinal region in a sitting position or during walking is improved.

Dimensions of the non-joined part <NUM> may be appropriately determined. However, in the case of use for infants, a front-back direction dimension may be set to about <NUM> to <NUM> mm, and a width direction dimension may be set to about <NUM> to <NUM> mm. It is preferable that a front edge of the non-joined part <NUM> (a site located closest to the front side in the case of a curve) is located at the back side portion of the front side half fallen part 68F.

In particular, when the elastic member in the stretchable region A2 at the lower waist portion of the front side outer member 12F extends to the inside of the non-joined part <NUM> formed at both end portions of the crotch side of the front side outer member 12F in the width direction, fitting of the inguinal region is more preferable. In addition, when the bending is adopted as the side gather <NUM> of the first embodiment described above, and the front side half fallen part 68F is provided, fitting of the inguinal region is further improved. Further, it is more preferable that the front side half fallen part 68F is the same as the crotch side edge of the front side outer member 12F or extends further to the center side in the front-back direction as described above. Further, in a case in which the absorbent body <NUM> has an hourglass shape, when the front side half fallen part 68F is located on the absorbent body without overlapping the narrower portion 56N, a root of the three-dimensional gather is stabilized, and the front side half fallen part 68F is easy to stand, which is preferable.

Meanwhile, when inner and outer joined portions <NUM> of the back side outer member 12B are provided to extend over both end portions in the width direction over the whole in the front-back direction, the inner member <NUM> rarely bites into the intergluteal cleft, which is preferable. In this case, when the bending mode is adopted as the side gathers <NUM> of the first embodiment described above, and the back side half fallen part 68B is provided, the tip side part 60A of the three-dimensional gather rarely falls in the opposite direction due to an inclination toward the intergluteal cleft, which is preferable. Further, as described above, when the back side half fallen part 68B is the same as the front edge of the back side outer member 12B or extends to the center side in the front-back direction LD, prevention of biting of the inner member <NUM> into the intergluteal cleft is further improved, the gluteal cover portion C is rarely shifted in the case of including the gluteal cover portion C, and ability to maintain covering of the gluteal region becomes excellent. It is more preferable that a front-back direction length of the back side half fallen part 68B is longer than a front-back direction length of the back side fallen part <NUM>. Further, in a case in which the absorbent body <NUM> has the hourglass shape, when the back side half fallen part 68B is located on the absorbent body without overlapping the narrower portion 56N, in particular, the inner member <NUM> rarely bites into the intergluteal cleft, which is preferable.

In the case of adopting the bending mode as the side gather <NUM> of the first embodiment, when both the front side half fallen part 68F and the back side half fallen part 68B are provided, and a length of the back side half fallen part 68B with respect to a length of the front side half fallen part 68F is in a range of <NUM> to <NUM>, the three-dimensional gather can stand long and high, and each of the tip side part 60A and the root side part 60B is not excessively free. Thus, fitting of the entire periphery of the leg becomes excellent.

Terms below in the specification have meanings below unless otherwise specified in the specification.

· The "front-back (longitudinal) direction" refers to a direction connecting a ventral side (front side) and a dorsal side (back side), and the "width direction" refers to a direction (left-right direction) orthogonal to the front-back direction.

· The "front surface side" refers to a side close to the skin of the wearer when the underpants-type disposable diaper is worn, and the "back surface side" refers to a side far from the skin of the wearer when the underpants-type disposable diaper.

· The "front surface" refers to a surface of the member on the side close to the skin of the wearer when the underpants-type disposable diaper is worn, and the "back surface" refers to a surface of the member on the side far from the skin of the wearer when the underpants-type disposable diaper.

· The "area ratio" refers to an area of a ratio of a target portion to a unit area, and is expressed as a percentage by dividing a total area of target portions (for example, holes) in a target region (for example, the cover nonwoven fabric) by an area of the target region. In an embodiment in which a plurality of target portions is provided at intervals, it is desirable to set a target region having a size such that ten or more target portions are included and obtain an area ratio. For example, the area ratio of the holes can be measured by the following procedure, for example, using the product name VHX-<NUM> manufactured by KEYENCE Corporation, under the measurement conditions of <NUM> times.

· The "stretch rate" refers to a value when the natural length is set to <NUM>%.

· The "gel strength" is measured as follows. <NUM> of a super absorbent polymer is added to <NUM> of artificial urine (mixture of urea: <NUM> wt%, sodium chloride: <NUM> wt%, calcium chloride dihydrate: <NUM> wt%, magnesium sulfate heptahydrate: <NUM> wt%, and ion exchanged water: <NUM> wt%) and stirred using a stirrer. After the produced gel is left in a temperature and humidity testing chamber of <NUM> × <NUM>%RH for three hours, the temperature is returned to room temperature, and gel strength is measured using a card meter (Curdmeter-MAX ME-<NUM>, manufactured by I. Techno Engineering Co.

· The "basis weight" is set as below. A sample or a specimen is pre-dried, and then is left in a test room or a device in a standard state (temperature <NUM> ± <NUM>, relative humidity <NUM>% or less in a test location), and is put in a constant weight state. Pre-drying refers to setting the weight of the sample or the specimen to a constant weight in an environment in which relative humidity is in a range of <NUM> to <NUM>% and temperature does not exceed <NUM>. Pre-drying is unnecessary for a fiber having an official moisture regain of <NUM>%. A sample having dimensions of <NUM> × <NUM> (± <NUM>) is cut off from the specimen in the constant weight state using a sampling template (<NUM> × <NUM>, ± <NUM>). A weight of the sample is measured and multiplied by <NUM> to calculate a weight per square meter, and the weight is set to the basis weight.

· A "thickness" is automatically measured using an automatic thickness measurement apparatus (KES-G5 handy compression measurement program) under the condition of a load of <NUM> N/cm<NUM> and a pressurized area of <NUM><NUM>.

· The "water absorption capacity" is measured by JIS K7223-<NUM> "water absorption capacity test method for superabsorbent resin".

· The "water absorption rate" is set to a "time to an end point" when JIS K7224-<NUM> "water absorption rate test method for super absorbent resin" is performed using <NUM> of super absorbent polymers and <NUM> of physiological saline.

· The "spread state" refers to a flatly spread state without contraction or slack.

· Dimensions of each portion refer to dimensions in a spread state rather than a natural length state unless otherwise stated.

· When there is no description about an environmental condition in a test or measurement, it is presumed that the test or measurement is performed in a test room or a device in a standard state (temperature <NUM> ± <NUM>, relative humidity <NUM>% or less in a test location).

Claim 1:
An underpants-type disposable diaper comprising:
a front side outer member (12F) forming a lower torso portion of a front body, and
a back side outer member (12B) forming a lower torso portion of a back body,
the front side outer member (12F) and the back side outer member (12B) being separated from each other and spaced apart in a front-back direction (LD) in a middle in the front-back direction(LD);
an inner member (<NUM>) including:
a liquid pervious top sheet (<NUM>) located on a front surface side,
a liquid impervious sheet (<NUM>) formed of a resin film located on a back surface side, and
an absorbent body (<NUM>) interposed therebetween, extending in the front-back direction (LD) from the front side outer member (12F) to the back side outer member (12B) and being joined to each of the front side outer member (12F) and the back side outer member (12B);
a waist opening (WO) and a pair of left and right leg openings being formed by joining respective pairs of side portions of the front side outer member (12F) and the back side outer member (12B); and
a display sheet (<NUM>) formed of a resin film and being provided between at least one of the front side outer member (12F) and the back side outer member (12B) and the inner member (<NUM>);
wherein each outer member (12B,12F) has a plurality of elastic members (<NUM> and <NUM>, or <NUM>) in the front-back direction zones having the absorbent body (<NUM>), namely a lower waist portion U or a gluteal cover portion C, forming a non-stretchable region (A1) in a middle portion in the width direction (WD) including a part or a whole of a portion overlapping the absorbent body (<NUM>) and a stretchable region (A2) at both sides thereof in the width direction (WD);
wherein:
a perforated nonwoven fabric (<NUM>) is interposed in a region between the display sheet (<NUM>) and the liquid impervious sheet (<NUM>), extending from a crotch side edge of the outer member overlapping the display sheet (<NUM>) and toward a side of the waist opening (WO),
the perforated nonwoven fabric being provided with a plurality of holes (<NUM>) spaced at intervals and penetrating therethrough from the front to the back of the nonwoven fabric, and
an internal surface and an external surface of the perforated nonwoven fabric are bonded to facing surfaces, respectively, by a hot melt adhesive.