Disposable diaper

A diaper is provided in a transverse middle of a crotch region with a pad seat formed from top- and backsheets. The pad seat has a pair of extensions bifurcated from a rear end of the pad seat toward respective tape fasteners. In the course of wearing the diaper as well as during use of the diaper, a tensile force functioning to pull side flaps outward as viewed in a transverse direction of the article is transmitted to the respective extensions and pulls the pad seat so that the pad seat may be tightened so as to press a pad laid in the pad seat against the wearer's skin.

RELATED APPLICATIONS

The present application is based on, and claims priority from, Japanese Application Number 2004-142678, filed May 12, 2004, the disclosure of which is hereby incorporated by reference herein in its entirety.

BACKGROUND OF THE INVENTION

The present invention relates to disposable diapers of open-type adapted to be worn with body waste absorbing and retaining pad carried thereon.

There have been known disposable diapers of open-type defining a front waist region, a rear waist region and a crotch region extending between these waist regions. The diapers comprise a liquid-pervious topsheet, a liquid-impervious backsheet and a liquid-absorbent core interposed between these sheets and extending between the front and rear waist region. A pair of end flaps extend in a transverse direction of the diaper outside longitudinally opposite ends of the core and a pair of side flaps extend outside transversely opposite side edges of the core. The diaper is adapted to be worn with a body waste care pad laid on the topsheet. One of such diapers are disclosed, for example, in Japanese Unexamined Patent Application Publication No. 2003-116910 (hereinafter referred to as “Reference”).

In the diaper of disclosed in Reference, the crotch region is formed in its transverse middle with a depressed zone in which the pad is to be laid. The depressed zone is formed from the top- and backsheets except the core and has an elliptical shape which is relatively long in the longitudinal direction. The depressed zone is provided along its peripheral edge with a circularly extending stretchable elastic member contractably attached thereto. A pair of tape fasteners is attached to the side flaps in the rear waist region, respectively, and extends in the transverse direction. Contractile force of the elastic member functions to reduce an area of the depressed zone and thereby to further depress this zone in a thickness direction of the diaper so that the pad can be securely laid in the depressed zone. Consequently, it is unlikely that the pad might be out of alignment during use of the diaper. To wear the diaper disclosed in Reference, the pad is laid in the depressed zone, then the side flaps in the rear waist region are placed upon outsides of the respective side flaps in the front waist region, and free ends of the respective tape fasteners are fastened to the outer surface of the front waist region while the tape fasteners are pulled outward in the transverse direction to connect the front and rear waist regions with each other. Upon connection of the front and rear waist regions, the diaper is formed with a waist-hole and a pair of leg-holes.

In the case of the diaper disclosed in Reference, the side flaps in the rear waist region are pulled outward in the transverse direction as the free ends of the respective tape fasteners are fastened to the outer surface of the front waist region to wear the diaper. Once the front and rear waist regions having been connected with each other by means of the tape fasteners around the wearer's body, these side flaps in the front and rear waist regions pull one another to be strained outward in the transverse direction. While the side flaps continue to be strained outward in the transverse direction in the course of wearing the diaper as well as during use of the diaper, a tensile force exerted upon these side flaps is not transmitted to the elliptical depressed zone so efficiently to pull the depressed zone outward in the transverse direction and thereby to keep the depressed zone strained outward in the transverse direction. Consequently, the depressed zone remains slack down in the thickness direction of the diaper in the course of wearing the diaper as well as during use of the diaper, making it impossible for this known diaper to press the pad laid in the depressed zone against the wearer's skin. So far as the pad is not in close contact with the wearer's skin, a clearance is left between the pad and the wearer's skin and body waste can not be reliably absorbed and retained by the pad.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide disposable diapers of open-type improved so that the body waste care pad can be kept in close contact with the wearer's skin and body waste can be reliably absorbed and contained by the pad.

The present invention is directed to a disposable diaper of open-type having a front waist region, a rear waist region and a crotch region extending between these waist regions, the diaper comprising a skin-faciable liquid-pervious topsheet, a skin-opposite liquid-impervious sheet and a liquid-absorbent core of a given thickness interposed between these sheets and extending between the front and rear waist regions. The diaper is formed with a pair of end flaps extending in a transverse direction outside longitudinally opposite ends of the core and a pair of side flaps extending in a longitudinal direction outside transversely opposite side edges of the core and the side flaps in the rear waist region being provided with tape fasteners attached thereto so as to extend in the transverse direction so that the diaper is worn with a body waste care pad laid on the topsheet after the tape fasteners have been anchored on outer surface of the front waist region to connect the front and rear waist regions with each other.

The front and rear waist regions and the crotch region or at least the crotch region are or is provided along a transverse middle thereof with a pad seat formed by a cavity defined in a middle zone of said core and portions of the top- and backsheets located in the cavity39aand extending in the longitudinal direction and the pad seat includes a pair of first extensions bifurcated from a rear end of the pad seat lying on the side of the rear waist region and extending toward the tape fasteners.

The present invention may include the following preferred embodiments.

The pad seat includes a pair of second extensions bifurcated from a front end of the pad seat lying on a side of the front waist region and extending toward a pair of corners defined by crossing points of the end flaps and the side flaps in the front waist region.

The pad seat is provided in a vicinity of side edges thereof with stretch- and contractable elastic members contractably attached thereto so as to extend in the longitudinal direction.

The stretch- and contractable elastic members fully extend over the pad seat and longitudinally opposite ends of the elastic members extend under the lower surfaces of respective the cores lying in the front and rear waist regions.

The stretch- and contractable elastic members respectively describe generally circular arcs which are convex inward as viewed in the transverse direction of the pad seat so that a dimension by which the elastic members are spaced from each other in the transverse direction is minimized at a longitudinal middle of the pad seat.

The stretch- and contractable elastic members extend into the first and second extensions of the pad seat.

The stretch- and contractable elastic members have tensile stress in a range of 0.05 to 4.0 N.

The topsheet extends along an inner peripheral wall of the core surrounding the pad seat from the upper surface toward the lower surface of the core, the top- and backsheets constituting the pad seat are bonded to each other on the side of the lower surface of the core and a difference in level in proportion to a thickness dimension of the core is formed between the upper surface of the core and the pad seat.

The disposable diaper according to the present invention is primarily characterized in that, in the course of wearing the diaper by anchoring the free ends of the respective tape fasteners on the outer surface of the front waist region as well as during use of the disposable diaper with the front and rear waist regions connected to each other by means of the tape fasteners, the tensile force functioning to pull the side flaps in the rear waist region outward in the transverse direction is transmitted to the first extensions so as to tighten the segment of the pad seat extending in the rear waist region and thereby to press the pad against the wearer's skin. As used herein “tighten the segment of the pad seat” means that slack and/or wrinkle is took up and held in a strained state. This diaper ensures the pad to be held in close contact with the wearer's skin in the course of wearing the diaper as well as during use of the diaper without leaving any clearance between the pad and the wearer's skin and thereby ensures body waste to be reliably absorbed and contained by the pad.

In the case of the diaper wherein the pad seat includes a pair of second extensions bifurcated from a front end of the pad seat lying on the side of the front waist region and extending toward a pair of corners defined by crossing points of the end flaps and the side flaps in the front waist region, the tensile force functioning to pull the side flaps outward in the transverse direction is transmitted to the first extensions in the course of wearing the diaper as well as during use of the diaper. During use of the diaper, the tensile force functioning to pull the side flaps in the front waist region is transmitted to the second extensions so as to tighten the segment of the pad seat extending in the front waist region and thereby to press the pad laid in the pad seat against the wearer's skin. This diaper ensures the pad to be held in close contact with the wearer's skin without leaving any clearance between the pad and the wearer's skin and thereby ensures body waste to be reliably absorbed and contained by the pad.

In the case of the diaper wherein the pad seat is provided in the vicinity of side edges thereof with stretch- and contractable elastic members contractably attached thereto so as to extend in the longitudinal direction, the contractile force of the elastic members raises the pad seat toward the wearer's skin and thereby presses the pad laid in the pad seat against the wearer's skin. In this way, the pad is reliably held in close contact with the wearer's skin so that body waste can be reliably absorbed and contained by the pad. This diaper ensures that, in the course of wearing the diaper as well as during use of the diaper, the pad seat is pulled by the tensile force exerted on the side flaps and the pad seat strained in this manner causes the elastic members to be stretched. In other words, tightening of the pad seat and contractile force of the elastic members exerted on the pad seat can be efficiently utilized to hold the pad in close contact with the wearer's skin.

In the diaper wherein the stretch- and contractable elastic members fully extend over the pad seat and longitudinally opposite ends of the elastic members extend under the lower surfaces of the respective cores lying in the front and rear waist regions, tightening of the pad seat and contractile force of the elastic members can be effectively utilized to press the pad against the wearer's skin. In addition, contractile force of the elastic members causes the cores lying in the front and rear waist regions to be pressed against the wearer's skin and to hold these cores also in close contact with the wearer's body. This diaper ensures that, even if any amount of body waste leaks out from the pad, such amount of body waste is reliably absorbed and retained by the cores lying in the front and rear waist regions. In this way, there is no anxiety that any amount of body waste might leak off from the diaper.

In the case of the diaper wherein the stretch- and contractable elastic members respectively describe circular arcs which are convex inward as viewed in the transverse direction of the pad seat so that a dimension by which the elastic members are spaced from each other in the transverse direction is minimized at a longitudinal middle of the pad seat, the contractile force of these elastic members may act fully on the pad seat to raise the pad seat as a whole toward the wearer's skin. Thus the pad laid in the seat can be fully pressed against the wearer's skin, ensuring body waste to be reliably absorbed and retained by the pad. In this diaper, pad seat is pulled outward in the transverse direction and tightened so that, in the course of wearing the diaper as well as during use of the diaper, the elastic members can be stretched along curves of the wearer's crotch region. In this way, tightening of the pad seat and contractile force of the elastic members acting on the pad seat may be effectively utilized to hold the pad against the wearer's skin.

In the case of the diaper wherein the stretch- and contractable elastic members extend into the first and second extensions of the pad seat, the tensile force transmitted from the side flaps to the first and second extensions functions to stretch the elastic members, in the course of wearing the diaper as well as during use of the diaper, so that tightening of the pad seat and contractile force of the elastic members exerted on the pad seat may be effectively utilized to hold the pad in close contact with the wearer's skin.

In the case of the diaper wherein the stretch- and contractable elastic members have tensile stress in a range of 0.05 to 4.0 N, the contractile force of the elastic members exerted on the pad seat is sufficient to raise the pad seat toward the wearer's skin and to hold the pad in close contact with the wearer's skin.

In the case of the diaper a difference in level in proportion to a thickness dimension of the core is formed between the upper surface of the core and the pad seat, a body weight of the wearer exerted on the pad depresses the pad downward in the thickness direction of the diaper along the difference in level. Consequently, it is unlikely that the pad might become bulky and create a feeling of discomfort against the wearer. The pad seat is tightened and maintained in such tightened state so long as the diaper is worn and, as soon as the pad is relieved of the wearer's body pressure, the pad can reliably restore its initial thickness and comes again in close contact with the wearer's skin. In this way, this diaper ensures the pad to be held in close contact with the wearer's skin and thereby ensures body waste to be reliably absorbed and retained by the pad.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Details of a disposable diaper according to the present invention will be more fully understood from the description given hereunder with reference to the accompanying drawings.

FIG. 1is a perspective view showing a disposable diaper20A with a pad36laid in a pad seat39,FIG. 2is a partially cutaway plan view showing the diaper20A ofFIG. 1with the pad36not shown,FIG. 3is a sectional view taken along the line3—3inFIG. 1andFIG. 4is a sectional view taken along the line4—4inFIG. 1. InFIGS. 1 and 2, a transverse direction is indicated by an arrow L, a longitudinal direction is indicated by an arrow M and a thickness direction is indicated by an arrow N (inFIG. 1alone).FIG. 2shows the diaper20A as developed in the longitudinal direction as well as in the transverse direction against contractile force of stretch- and contractible elastic members48,51,54. As used herein, “inner surfaces” of top- and backsheets24,25and leak-barrier sheets31constituting the diaper20A refer to the surfaces thereof facing a core26and “outer surfaces” of these sheets24,25,31refer to the surfaces thereof facing away from the core26. As used herein, “upper surface” of the core26refers to the surface facing the topsheet24and “lower surface” of the core26refers to the surface thereof facing the backsheet25. As used herein, “inner surfaces” of a topsheet58and a backsheet59constituting the pad36refer to the surfaces thereof facing a core60and “outer surface” of these sheets58,59refer to the surfaces thereof facing away the core60.

As viewed in the longitudinal direction, the diaper20A has a front waist region21, a rear waist region23and a crotch region22extending between these waist regions21,23. The diaper20A comprises the skin-faciable liquid-pervious topsheet24, the skin-opposite liquid-impervious sheet25and the liquid-absorbent core26of a given thickness interposed between the top- and backsheets24,25and extending between the front and rear waist regions21,23. The diaper20A is formed with a pair of end flaps29extending in the transverse direction outside longitudinally opposite ends27of the core26and a pair of side flaps30extending in the longitudinal direction outside transversely opposite side edges28of the core26.

The side flaps30are provided with a pair of liquid-impervious leak-barrier sheets31extending in the longitudinal direction so as to be spaced from and opposed to each other. In the crotch region22, the side flaps30curve inward as viewed in the transverse direction of the diaper20A so as to describe generally circular arcs. Thus, the diaper20A this has a generally hourglass-like planar shape as shown inFIG. 2. The side flaps30B in the rear waist region23are respectively provided with tape fasteners32extending in the transverse direction. The tape fasteners32respectively have fixed ends33and free ends34. The front waist region21is provided with a target tape strip35on which the free ends34of the respective tape fasteners32are releasably anchored. As will be understood fromFIG. 1, the diaper20A is adapted to be worn with the body waste care pad36laid in a depressed zone39as will be described later in details after the front and rear waist regions21,23have been connected with each other by means of the tape fasteners32.

The topsheet24is formed from a hydrophilic fibrous nonwoven fabric. The backsheet25is formed from a composite sheet composed of a hydrophobic fibrous nonwoven fabric37and a breathable liquid-impervious plastic film38laminated together. The leak-barrier sheets31are formed from a water repellent finished hydrophobic fibrous nonwoven fabric. The core26is formed from a mixture of particulate or fibrous superabsorbent polymers and fluff pulp fibers or a mixture of particulate or fibrous superabsorbent polymers, fluff pulp fibers and thermoplastic synthetic resin fibers, in any case, compressed to a thickness required to have a stiffness higher than those of the top- and backsheets24,25and the leak-barrier sheets31. The core26is entirely wrapped with a tissue paper (not shown) in order to prevent the core26from getting out of its initial shape. The core26is bonded to the respective inner surfaces of the top- and backsheets24,25.

The crotch region22is formed in its transverse middle with a pad seat39extending in the longitudinal direction. The pad seat39is formed by a cavity39adefined in a middle zone of the core26and portions of the top- and backsheets24,25located in the cavity39a. The cavity39ais contoured by a periphery consisting of a front end40extending in the transverse direction in the front waist region21, a rear end41extending in the transverse direction in the rear waist region41and side edges42extending in the longitudinal direction between these front and rear ends40,41. The pad seat39has a pair of first extensions43bifurcated from the rear end41and extending toward the respective tape fasteners32. The extensions43obliquely extend from the rear end41of the pad seat39toward the respective tape fasteners32so as to be gradually spaced from a longitudinal centerline M1bisecting a transverse dimension of the diaper20A. In addition, these extensions43are tapered from the rear end41of the pad seat39toward the respective tape fasteners32. The pad seat39including the extensions43is defined by segments of the top- and backsheets24,25not including the core26and surrounded by an inner peripheral wall44of the core26. A segment of the pad seat39including the extensions43has a stiffness lower than that of the remaining segment of the pad seat39in which the core26is present.

In the pad seat39, the topsheet24extends along the inner peripheral wall44surrounding the pad seat39from the upper surface toward the lower surface of the core26and the inner surface of the topsheet24is bonded to the inner peripheral wall44of the core26. On the side of the lower surface of the core26, the top- and backsheets24,25forming the pad seat39have the respective inner surfaces bonded to each other in an intermittent manner. The pad seat39is depressed in the thickness direction of the diaper20A. A difference in level N1in proportion to a thickness dimension of the core26is formed between the upper surface of the core26and the pad seat39.

The leak-barrier sheets31are provided on the side of the outer surface of the topsheet24. These leak-barrier sheets31have proximal zones45extending in the longitudinal direction on the side flaps30, distal zones46extending in the longitudinal direction in parallel to the proximal zones45and normally biased to rise up above the topsheet24and longitudinally opposite ends47lying on the end flaps29and collapsed inward as viewed in the transverse direction of the diaper20A. The proximal zones45as well as the distal zones46extend between the end flaps29. The distal zones46are provided, in the vicinity of respective uppermost edges, with stretch- and contractable elastic members48contractably attached thereto so as to extend in the longitudinal direction. Specifically, these elastic members48are secured to the respective distal zones46with adhesives under tension at a given ratio in the longitudinal direction. These elastic members48contract and the distal zones46also contract in the longitudinal direction as the diaper20A is left to curve inward. Consequently the distal zones46rise up above the topsheet24to form barriers against body waste.

Respective end portions49,50of the top- and backsheets24,25extending in the longitudinal direction outward beyond the ends27of the core26cooperate with the ends47of the leak-barrier sheets31to define the end flaps29. In each of the end flaps29, the respective end portions49,50of the top- and backsheets24,25are overlapped with the ends47of the leak-barrier sheets31wherein the top- and backsheets24,25have the respective inner surfaces bonded together and the outer surface of the topsheet24is bonded to the inner surfaces of the respective leak-barrier sheets31. The end flap29in the rear waist region23is provided with a plurality of waist-surrounding elastic members51contractably secured thereto so as to extend in the transverse direction with adhesives. These waist-surrounding elastic members51are interposed between the respective ends49,50of the top- and backsheets24,25and secured to the respective sheets24,25of these sheets24,25with adhesives under tension at a given ratio in the transverse direction.

Respective side edge portions52,53of the top- and backsheets24,25extending in the transverse direction outward beyond the side edges28of the core26cooperate with the proximal zones45of the respective leak-barrier sheets31to define the side flaps30. In each of the side flaps29, the side edge portion52of the topsheet24extends in the transverse direction outward slightly beyond the side edge28of the core26while the side edge portion53of the backsheet25as well as the proximal zone45of the leak-barrier sheet31extend in the transverse direction outward beyond the side edge portion52of the topsheet24. In each of the side flaps30, the respective side edge portions52,53of the top- and backsheets24,25are overlapped with the proximal zone45of the leak-barrier sheet31wherein the top- and backsheets24,25have the respective inner surfaces bonded together and the inner surface of the topsheet24and the outer surface of the backsheet25are bonded to the inner surface of the leak-barrier sheet31. Each of the side flaps30is provided with a plurality of leg-surrounding elastic members54contractably attached with adhesives thereto. In each of the side flaps30, the leg-surrounding elastic members54are interposed between the side edge portion53of the backsheet25and the proximal zone45of the leak-barrier sheet31and bonded to the respective inner surface of these sheets25,31with tension at a given ratio in the longitudinal direction.

The tape fastener32is formed from a fibrous nonwoven fabric. The fixed end33of the tape fastener32is interposed between the side edge portion53of the backsheet25and the proximal zone45of the leak-barrier sheet31and bonded to the respective inner surfaces of these sheets25,31. The tape fastener32is provided on the free end34with a hook member55. In a state of the tape fastener32illustrated inFIG. 1, the free end34is folded inward as viewed in the transverse direction of the diaper20A and temporarily held on the side flap30B (i.e., on the outer surface of the leak-barrier sheet31). It should be understood that the hook member55may be replaced by a pressure-sensitive adhesive coated on the free end34and protectively covered with a release sheet. The target tape strip35comprises a base56and a loop member57protuberated from the base56and has a rectangular shape which is relatively long in the transverse direction. The base56constituting the target tape strip35is bonded to the outer surface of the backsheet25. When it is desired to coat the free end34of the tape fastener32with a pressure-sensitive adhesive, the target tape strip35is preferably formed from a plastic film.

The pad36comprises a wearer-faciable liquid-pervious topsheet58, a wearer-opposite liquid-impervious backsheet59and a liquid-absorbent core60of a given thickness interposed between these top- and backsheets58,59and bonded to respective inner surfaces of these sheets58,59. The pad36has a rectangular shape which is relatively long in the longitudinal direction and contoured by longitudinally opposite ends61extending in the transverse direction and transversely opposite side edges62extending in the longitudinal direction. Along the ends as well as along the side edges62, the top- and backsheets58,59are overlapped together and have respective inner surfaces bonded to each other. The topsheet58is formed from a hydrophilic fibrous nonwoven fabric and the backsheet59is formed from a hydrophobic fibrous nonwoven fabric. The core60is formed from a mixture similar to the mixture forming the core26provided integrally with the diaper20A. The mixture destined to form the core60is also entirely wrapped with a tissue paper (not shown). It is also possible to form the pad36from such liquid-absorbent core60entirely wrapped with a liquid-pervious sheet.

FIG. 5is a perspective view illustrating a sequence in which the diaper20A is worn.FIG. 5shows the diaper20A as viewed from the side of the rear waist region23.FIG. 5shows one of the tape fasteners32anchored on the target tape strip35without showing the wearer. This diaper20A is worn in the sequence as follows: The pad36is laid in the pad seat39so that the backsheet59of the pad36may be put in contact with the topsheet24of the diaper20A. Then, the wearer' buttock is placed on the rear waist region23and the diaper20A is folded upward along the crotch region22to place the front waist region21on the wearer's abdominal region. Now the tape fasteners32may be pulled outward in the transverse direction with the respective free ends34held by the fingers until the side flaps30B in the rear waist region23are placed upon the respective outer sides of the side flaps30A in the front waist region21and then the free ends34of the respective tape fasteners32are anchored on the target tape strip35(i.e., on the outer surface of the front waist region21) by means of the hook members to connect the front and rear waist regions21,23with each other. Upon connection of these front and rear waist regions21,23, the diaper20A is formed with a waist-hole63and a pair of leg-holes64below the waist-hole63. Of the diaper20A worn in this manner, the front waist region21comes in contact with the wearer's abdominal region, the crotch region22comes in contact with the wearer's crotch region and the rear waist region23comes in contact with the wearer's buttock and back.

In the course of wearing the diaper20A completed by anchoring the respective tape fasteners32on the target tape strip35, the side flaps30B in the rear waist region23are pulled outward in the transverse direction indicated by an arrow L1inFIG. 5and the tensile force functioning to pull the side flaps30B outward in the transverse direction is transmitted to the first extensions43. It is also true during use of the diaper20A having the front and rear waist regions21,23connected with each other by the tape fasteners32in this manner. Specifically, the side flaps30A in the front waist region21and the side flaps30B in the rear waist region23pull each other so that the side flaps30A,30B are pulled outward in the transverse direction as indicated by the arrows L1, L2inFIG. 5and the tensile force functioning to pull the side flaps30B outward in the transverse direction is transmitted to the first extensions43. The segment of the pad seat39including the first extensions43has a stiffness lower than a stiffness of the remaining segment in which the core26is present and, in addition, the extensions42extend toward the respective tape fasteners32. Such a unique arrangement ensures that the tensile force exerted on the side flaps30B in the course of wearing the diaper20A and during use of the diaper20A is reliably transmitted from the side flaps30B to the respective extensions43to tighten the pad seat39(i.e., to pick up slack and wrinkle of the pad seat39). The pad36is pressed against the wearer's skin as the pad seat39is tightened in this manner. In this way, it is ensured that body waste discharged in the diaper worn is reliably absorbed by the core through the topsheet58of the pad36.

In the course of wearing the diaper20A as well as during use of the diaper20A, the pad36is reliably pressed against the wearer's skin, leaving no clearance between the pad36and the wearer's skin so that body waste can be reliably absorbed and contained by the pad36. Should body waste partially leak from the pad seat39, such leakage of body waste can be absorbed and contained by the core26which is present around the pad seat39. In this way, leakage of body waste from the diaper20A can be reliably avoided.

A body weight of the wearer exerted on the pad36depresses the pad36downward in the thickness direction of the diaper20A along the difference in level N1. Consequently, it is unlikely that the pad36might become bulky and create a feeling of discomfort against the wearer. The pad seat39is tightened and maintained in such a tightened state so long as the diaper20A is worn and, as soon as the pad36is relieved of the wearer's body pressure, the pad36can reliably restore its initial thickness and comes again in close contact with the wearer's skin.

The segment of the pad seat39including the first extensions43has a stiffness value in a range of 0.1 to 2.0 mN·cm, preferably, in a range of 0.8 to 1.5 mN·cm. If the stiffness of the pad seat39exceeds 2.0 mN·cm, it will be difficult for the tensile force exerted on the side flaps30B to tighten the pad seat39and sometimes to press the pad36against the wearer's skin even if such tensile force is transmitted to the pad seat39. The stiffness value was measured in pursuance of Gurley's Method (JIS L 1096-01-8.20.1). The measurement was carried out using a method comprising the steps as follow:(1) The pad seat39was cut out from the diaper20A to obtain samples each having a longitudinal dimension of 25 mm and a transverse dimension of 38.0 mm for measurement of stiffness values. For measurement of the stiffness values, the Gurley's Stiffness Tester was used.(2) One of longitudinally opposite end portions of the sample was held by a chuck of the tester and the other end portion was maintained in engagement with a pendulum of the tester and the tester was initialized by loading an auxiliary weight so that the tester scale may point the readings in a range of 3 to 6. The tester was turned on and a scale reading of the moment at which the pivot rod of the pendulum was separated from the sample was recorded as a first stiffness value. Now the other of longitudinally opposite ends of the sample was held by the chuck of the tester and the opposite end was maintained in engagement with the pendulum of the tester. The tester was initialized by loading the auxiliary weight so that the tester scale may point the scale readings in a range of 3 to 6. The tester was turned on and the scale reading of the moment at which the pivot rod of the pendulum was separated from the sample was recorded as a second stiffness value. An average value of these first and second stiffness values obtained in this manner was recorded as the stiffness value of the sample. The stiffness value of the first sample was in a range of 0.1 to 2.0 mN·cm. The stiffness value of the sample was adopted as the stiffness of the pad seat39.

FIG. 6is a perspective view showing the diaper20B according to one preferred embodiment with the pad36laid in the pad seat39,FIG. 7is a partially cutaway plan view showing the diaper20B ofFIG. 6with the pad36not shown,FIG. 8is a sectional view taken along the line8—8inFIG. 6andFIG. 9is a sectional view taken along the line9—9inFIG. 6. InFIGS. 6 and 7, the transverse direction is indicated by the arrow L, the longitudinal direction is indicated by the arrow M and a thickness direction is indicated by the arrow N (inFIG. 6alone).FIG. 7shows the diaper20B as developed in the longitudinal direction as well as in the transverse direction against contractile force of the stretch- and contractable elastic members48,51,54,66.

The diaper20B is of open-type adapted to be worn with the front and rear waist regions21,23connected to each other by means of the tape fasteners32after the body waste care pad36has been laid in the pad seat39. Similarly to the diaper20A ofFIGS. 1–5, the diaper20B also comprises the liquid-pervious topsheet24, the liquid-impervious backsheet25, the liquid-absorbent core26interposed between the top- and backsheets24,25and extending between the front and rear waist regions21,23and a pair of the liquid-impervious leak-barrier sheets31attached to the side flaps30so as to extend in the longitudinal direction. This diaper20B is distinguished from the diaper20A ofFIGS. 1–5in that the pad seat39has second extensions66and the pad seat39is provided with stretch- and contractable elastic members67,68. The remaining components similar to those in the diaper20A ofFIGS. 1–5are designated by similar references and repetitive description thereof will be eliminated.

The pad seat39has, in addition to a pair of the first extensions43, a pair of second extensions66bifurcated from the front end40and extending toward two corners65at which the end flaps29intersect with the side flaps30A in the front waist region21. The extensions66obliquely extend from the front end40of the pad seat39toward the respective corners65so as to be gradually spaced from the longitudinal centerline M1. These extensions66are tapered from the front end40toward the respective corners65.

The pad seat39is provided in the vicinity of the respective side edges42with a stretch- and contractable first elastic member67(stretch- and contractable elastic member) and a stretch- and contractable elastic member68(stretch- and contractable elastic member) both contractably attached thereto. These elastic members67,68are spaced from and opposed to each other and extend in the longitudinal direction. These elastic members67,68lie between the front and rear ends40,41and extend close to the first and second extensions43,66. These elastic members67,68are interposed between the top- and backsheets24,25and secured to the respective inner surfaces of these sheets24,25with adhesives under tension at a given ratio in the longitudinal direction.

FIG. 10is a perspective view showing the diaper20B worn as viewed from the side of the front waist region21. The sequence in which the diaper20C is worn is the same as the wearing sequence for the diaper20A as described in reference withFIG. 5and will not be repetitively described here. In the course of wearing the diaper20B completed by anchoring the respective tape fasteners32on the target tape strip35, the side flaps30B in the rear waist region23is pulled outward in the transverse direction indicated by the arrow L1inFIG. 5and the tensile force functioning to pull the side flaps30B outward in the transverse direction is transmitted to the first extensions43. It is also true during use of the diaper20B having the front and rear waist regions21,23connected with each other by the tape fasteners32in this manner. Specifically, the side flaps30A,30B in the front and rear waist regions21,23pull each other so that the side flaps30A,30B are pulled outward in the transverse direction as indicated by the arrows L1, L2inFIGS. 5,10and the tensile force functioning to pull the side flaps30A,30B outward in the transverse direction is transmitted to the first and second extensions43,66. The segment of the pad seat39including the first and second extensions43,66has a stiffness lower than a stiffness of the remaining segment in which the core26is present and, in addition, the extensions42extend toward the respective tape fasteners32and the extensions66extend toward the corners65. Such a unique arrangement ensures that the tensile force exerted on the side flaps30A,30B in the course of wearing the diaper20B and during use of the diaper20C is reliably transmitted from the side flaps30A,30B to the respective extensions43,66to tighten the pad seat39. The pad36is pressed against the wearer's skin as the pad seat39is tightened in this manner. In this way, it is ensured that body waste discharged on the diaper20C worn is reliably absorbed by the core through the topsheet58of the pad36.

The contractile force of the first and second elastic members67,68secured to the pad seat39in the vicinity of the side edges42thereof biases the pad seat39to rise up toward the wearer's skin and thereby to press the pad36laid in the seat39against the wearer's skin. In this way, body waste can be reliably absorbed and retained by the pad39. In the course of wearing the diaper20B as well as during use of the diaper20B, the pad seat39is pulled outward in the transverse direction so as to stretch the elastic members67,68. The pad seat39tightened in this manner and the contractile force of these elastic members67,68may be utilized to hold the pad36in close contact with the wearer's skin.

The segment of the pad seat39including the first and second extensions43,66has a stiffness value in a range of 0.1 to 2.0 mN·cm, preferably, in a range of 0.8 to 1.5 mN·cm. If the stiffness of the pad seat39is less than 0.1 mN·cm, the pad seat39will be excessively contracted, depending on the tensile stress of the elastic member67, under the contractile force of the elastic members67,68. In consequence, it will be impossible for the tensile force exerted on the side flaps30A,30B to tighten the pad seat39sufficiently to press the pad36against the wearer's skin even when such tensile force is more or less transmitted to the pad seat39. If the stiffness of the pad seat39exceeds 2.0 mN·cm, it will be difficult for the tensile force exerted on the side flaps30A,30B to tighten the pad seat39and sometimes to press the pad36against the wearer's skin even when such tensile force is more or less transmitted to the pad seat39. The stiffness value was measured in pursuance of Gurley's Method (JIS L 1096-01-8.20.1). The measurement was carried out using the same method as that used for the diaper20A ofFIGS. 1–5.

The tensile stress of the elastic members67,68is in a range of 0.05 to 4.0 N, preferably, in a range of 0.08 to 4.0 N. “The tensile stress of the elastic members67,68” as used herein refers to the tensile stress exhibited by each component constituting these elastic members67,68. If the tensile stress of the elastic members67,68is less than 0.05 N, the contractile force of these elastic members67,68acting upon the pad seat39will be insufficient, depending on the stiffness value of the pad seat39, to raise the pad seat39toward the wearer's skin and to press the pad36against the wearer's skin. If the tensile stress of the elastic members67,68exceeds 4.0 N, the contractile force of the elastic members67,68will excessively contract the pad seat39in the longitudinal direction and the tensile force exerted on the side flaps30A,30B will be insufficient to tighten the pad seat39and to press the pad36against the wearer's skin even when the tensile force exerted on the side flaps30A,30B is more or less transmitted to the pad seat39. The tensile stress of the elastic members67,68was measured by the method comprising the steps as follow:(1) The same elastic member (single) as those used in the diaper20B was prepared as a sample for measurement. For measurement of the tensile stress, the Tensile Tester manufactured by SHIMADZU CORPORATION was used.(2) Transversely opposite side edge portions of the sample were clamped by respective chucks of the tensile tester (a dimension over which each end portion was clamped by the chuck: about 10 mm, a length dimension of the sample measured between the chucks: about 100 mm). The sample was stretched in the longitudinal direction at a rate of 100 mm/min and, after the sample had been stretched by 300%, the tension was relieved. The sample was stretched again in the longitudinal direction at a rate of 100 mm/min and a force exerted on the tester at the moment the sample was stretched by 200% was obtained as the tensile stress value of the sample. The tensile stress value of the sample obtained in this manner was in a range of 0.05 to 4.0 N. The tensile stress of the sample obtained in this manner was adopted as the tensile stress exhibited by the single one of the elastic members67,68. As used herein “the sample was stretched by 200%” means that, for example, the sample having its inter-chuck dimension of 100 mm was stretched to 100 mm×2.0=200 mm.

FIG. 11is a perspective view showing a diaper20C according to another preferred embodiment with a pad36laid in a pad seat39,FIG. 12is a partially cutaway plan view showing the diaper20C ofFIG. 11with the pad36not shown,FIG. 13is a sectional view taken along the line13—13inFIG. 11andFIG. 14is a sectional view taken along the line14—14inFIG. 11. InFIGS. 11 and 12, a transverse direction is indicated by an arrow L, a longitudinal direction is indicated by an arrow M and a thickness direction is indicated by an arrow N (inFIG. 11alone).FIG. 12shows the diaper20C developed in the longitudinal direction as well as in the transverse direction against the contractile force of the stretch- and contractable elastic members48,51,54,66.

The diaper20C is of open-type adapted to be worn with the front and rear waist regions21,23connected to each other by means of the tape fasteners32after the body waste care pad36has been laid in the pad seat39. Similarly to the diaper20A ofFIGS. 1–5, the diaper20C also comprises the liquid-pervious topsheet24, the liquid-impervious backsheet25, the liquid-absorbent core26interposed between the top- and backsheets24,25and extending between the front and rear waist regions21,23and a pair of the liquid-impervious leak-barrier sheets31attached to the side flaps30so as to extending in the longitudinal direction. This diaper20C is distinguished from the diaper20A ofFIGS. 1–5in that the pad seat39has second extensions66and the pad seat39is provided with stretch- and contractable elastic members67,68. The remaining components similar to those in the diaper20A ofFIGS. 1–5are designated by similar references and repetitive description thereof will be eliminated.

The elastic members67,68are spaced from and opposed to each other and extend in the longitudinal direction. These elastic members67,68extend over the pad seat39in the longitudinal direction to the first and second extensions43,66wherein longitudinally opposite ends69of the respective elastic members67,68extend on the lower surface of the cores26lying in the front and rear waist regions21,23. These elastic members67,68respectively describe circular arcs which is convex inward as viewed in the transverse direction of the pad seat39so that a dimension by which these elastic members67,68are spaced from each other in the transverse direction is minimized at a longitudinal middle of the pad seat39. The elastic members67,68are interposed between the top- and backsheets24,25and bonded to the respective inner surfaces of these sheets24,25with tension at a given ratio in the longitudinal direction. The longitudinally opposite ends69of these elastic members67,68are interposed between the backsheet25and the core26and permanently bonded to the inner surface of the sheet25.

The elastic members67,68respectively describe circular arcs which is convex inward as viewed in the transverse direction of the pad seat39so that the contractile force of these elastic members67,68may act fully on the pad seat39to raise the pad seat39as a whole toward the wearer's skin. Thus the pad36laid in the seat39can be fully pressed against the wearer's skin, ensuring body waste to be reliably absorbed and contained by the pad36. The elastic members67,68extend into the first and second extensions43,66so that the tensile force transmitted to the first and second extensions43,66in the course of wearing the diaper20C as well as during use of the diaper20C can be exerted on the elastic members67,68via these extensions43,66and thereby the elastic members67,68can be stretched along curves of the wearer's crotch region. In this way, tightness of the pad seat39and contractile force of the elastic members67,68acting on the pad seat39may be effectively utilized to hold the pad36against the wearer's skin.

The elastic members67,68extend over the pad seat39in the longitudinal direction and the longitudinally opposite ends69of the respective elastic members67,68extend on the lower surface of the cores26lying in the front and rear waist regions21,23. With such arrangement, the contractile force of these elastic members67,68functions to press the cores26lying in the front and rear waist regions21,23against the wearer's skin and thereby to hold these cores26in close contact with the wearer's skin. The diaper20C ensures that body waste leaking out from the ends61of the pad36, if occurs, can be absorbed and retained by the cores26lying in the front and rear waist regions21,23. Consequently, it is not apprehended that body waste might leak out from the diaper20C.

Without departing from the scope of the present invention, it is possible to provide the pad seat39of the diaper20A shown inFIGS. 1–5with the elastic members67,68similar to those used in the diaper20B ofFIGS. 6–10or with the elastic members67,68similar to those used in the diaper20C ofFIGS. 11–14. The pad seat39of the diaper20A may have, in addition to a pair of the first extensions, a pair of the second extensions66bifurcated from the front end40of the pad seat39toward the corners defined by the crossing points of the end flaps29and the side flaps30A in the front waist region21. In the diaper20B ofFIGS. 6–10, the elastic members67,68may be provided so as to describe circular arcs which are convex inward as viewed in the transverse direction of the pad seat39.

These diapers20A,20B,20C maybe alternatively arranged so that the pad seat39extends not only along the transverse middle of the crotch region22but also along the transverse middle of the front and rear waist regions21,23. In this case, the pad seat39preferably extends from the crotch region22into a rear half of the front waist region21and into a front half of the rear waist region23. The diaper20A,20B,20C may be also alternatively arranged so that, in the pad seat39, the backsheet25extends along the inner peripheral wall44of the core26from the lower surface toward the upper surface of the core26, the inner surface of the backsheet25is permanently bonded to the inner peripheral wall44of the core26and the top- and backsheets24,25forming the pad seat39are permanently bonded to each other on the side of the upper surface of the core26.

Stock materials for the topsheets24,58is not limited to the hydrophilic fibrous nonwoven fabric but a hydrophobic fibrous nonwoven fabric having a plurality of fine apertures may be also used. Stock materials for the backsheet25is not limited to the composite nonwoven fabric but may be selected from the group consisting of a hydrophobic fibrous nonwoven fabric, breathable liquid-impervious plastic film and a composite sheet comprising two or more hydrophobic fibrous nonwoven fabric layers laminated together. It is possible without departing from the scope of the invention to form the backsheets25,59and the leak-barrier sheets31using a composite nonwoven fabric (SMN·nonwoven fabric, SMS nonwoven fabric or SMMS nonwoven fabric) consisting of a melt blown fibrous nonwoven fabric having a high water-resistance and a spun bond fibrous nonwoven fabric being high in strength as well as in flexibility laminated on at least one side of the melt blown fibrous nonwoven fabric. The elastic members48,51,54,66may be of natural or synthetic rubbers.

Stock materials for the fibrous nonwoven fabric layers may be selected from the group consisting of spun lace-, needle punch-, melt blown-, thermal bond-, spun bond- and chemical bond-nonwoven fabric layers. Component fibers of these nonwoven fabric layers may be selected from the group consisting of polyester-, polyacrylonitril-, polyvinyl chloride-, polyethylene-, polypropylene- and polystyrene-based fibers. It is also possible without departing from the scope of the invention to use the component fibers selected from the group consisting of core-sheath conjugate fibers, side-by-side conjugate fibers, modified macaroni fibers, microporous fibers and fused type conjugate fibers.

Bonding of the top- and backsheets24,25to each other, bonding of the core26to the sheets24,25, bonding of the leak-barrier sheets31to the sheets24,25, and securing of the elastic members48,51,54,66to the sheets24,25,31may be achieved by using adhesives or welding technique such as heat-sealing or sonic sealing. Adhesives may be selected from the group consisting of a hot melt adhesive, acrylic adhesive and rubber-based adhesive.

The adhesives are coated on the topsheet24, the backsheet25and the leak-barrier sheets31preferably in any one of spiral, wavy, zigzag, dotted or striped pattern. These sheets24,25,31may be coated with adhesives in such patterns to define adhesive-coated regions and adhesive-free regions in these sheets24,25,31and thereby to ensure that these sheets24,25,31are intermittently bonded one to another, the core26is intermittently bonded to the sheets24,25and the elastic members48,51,54,66are intermittently secured to the sheets24,25,31.