Disposable absorbent undergarment

[0002] The present invention relates to disposable absorbent undergarments and, more particularly, to undergarments of a pants type, such as disposable diapers, training pants for babies, incontinence pants, and the like.

[0003] U.S. Pat. No. 4,597,760 discloses a body fluid absorbent garment comprising an overgarment and a body fluid absorbent insert adapted to be detachably attached to the overgarment. The body fluid absorbent insert is used as a disposable diaper or reusable diaper. The insert comprises a liquid-permeable topsheet, a liquid-impermeable backsheet and an absorbent core. The insert is formed with adhesive regions at four corners of its lower surface and is adapted to be releasably fastened to predetermined regions provided on the upper surface of the overgarment.

[0004] In the body fluid absorbent undergarment described above circumferential stretchability is provided along a peripheral edge of a waist opening thereof for ease of wearability. However, if the peripheral edge is provided with such circumferential stretchability in the pants type garment having a waist-opening and a pair of leg-openings, it is necessary that a plurality of gathers be formed along the peripheral edge. When the above-mentioned known technique is applied to such an undergarment such that an absorbent pad corresponding to the insert may be detachably attached to the pants corresponding to the overgarment adjacent the waist-opening, the gathers formed along the peripheral edge extending along the waist line obstruct operation of the attachment and the pad can not be attached to the pants over an area required to achieve a reliable attachment. This deficient attachment area will result in an inadequate fastening force and an apprehension that the pad might unintentionally detach from the pants. In addition, the presence of the gathers in the fastening regions will make it difficult to find the fastening regions.

[0005] In view of the problem described above, it is a principal object of the invention to provide an undergarment having a circumferentially stretchable waist line peripheral edge which allows the absorbent pad to be easily fastened to the pants without apprehension that the pad might unintentionally detach from the pants.

[0006] The object set forth above is achieved, according to the invention, by an undergarment having a front section, rear section, and crotch section interposed therebetween. The undergarment comprises a pair of leg-openings and a circumferentially stretchable waist-opening. A body fluid absorbent pad, including a topsheet, a backsheet and an absorbent panel disposed therebetween extends longitudinally in and from the crotch section into proximity to the front and rear sections. In accordance with the invention, a pair of first suspending flaps are carried on inner sides of the front and rear sections in circumferentially middle regions thereof. The first suspending flaps hang down from and beyond a peripheral edge region of the waist-opening toward the crotch section and have provided at free ends thereof, first fastening means which are more rigid than the first suspending flaps. The pad has second suspending flaps, formed of at least one of the topsheet and the backsheet or both, extending outward beyond longitudinally opposite ends of the panel. The second suspending flaps are provided with second fastening means which are more rigid than the second suspending flaps and are adapted to be releasably fastened to the first fastening means.

[0007] FIG. 1 is a perspective view of incontinence pants partially broken away, of a specific embodiment of the inventive undergarment;

[0008] FIG. 2 is a sectional view taken along line II—II in FIG. 1; and

[0009] FIG. 3 shows the incontinence pants longitudinally opened out in a plan view with parts broken away.

[0010] Incontinence pants 1, as depicted in FIG. 1, comprise a main body 2 and an absorbent pad 3 detachably attached to the main body. The main body 2 has a front section 6, a rear section 7, and a crotch section 8 interposed therebetween. Transversely opposite side edges of the front and rear sections 6, 7 are bonded together, for example, along respective heat-seal regions 11 each intermittently extending in their vertical direction so as to form a waist-opening 9. The front and rear sections 6, 7 are provided along respective peripheral edge regions 16 of the waist-opening 9 with first elastic members 12, 13 each comprising a plurality of elastic elements attached thereto in their circumferentially tensioned or stretched condition. Second elastic members 14 are provided along lower waist regions 17 disposed downward of the peripheral edge regions 16. Second elastic members 14, each also comprising a plurality of elastic elements attached thereto in their circumferentially tensioned or stretched condition, are also provided. The crotch section 8 has a sheet member 15, which is stretchable in its longitudinal direction, that is joined at its longitudinally opposite ends 8A, 8B to lower ends 6A, 7A (FIG. 2) of the front and rear sections 6, 7, respectively, immediately above upper ends 10A of the respective leg-openings 10, to form a pair of leg-openings 10. The main body 2 is provided on its inner side with the absorbent pad 3 extending longitudinally in and from the crotch section 8 into a position adjacent to the front and rear sections 6, 7.

[0011] FIG. 2 is a sectional view taken along line II—II in FIG. 1. In the main body 2, each of the front and rear sections 6, 7 comprises a topsheet 25 and a backsheet 26, both made of a nonwoven fabric that are intermittently bonded to an air/moisture permeable plastic film 27 disposed therebetween. The first and second elastic members 13, 14 are disposed between the topsheet 25 and the film 27 and are secured to the inner surface of at least one of the topsheet 25 and film 27. The sheet member 15, as a component of the crotch section 8, comprises a topsheet 30 and a backsheet 31, both made of a nonwoven fabric, and an air/moisture-permeable plastic film 32 which is disposed therebetween and stretchable at least in its longitudinal direction. The topsheet 30 and the backsheet 31 are intermittently bonded to the film 32. In the main body 2, the film 27 assures that the front and rear sections 6, 7 have a desired tensile strength and the film 32 assures that the crotch section 8 has a desired tensile strength and stretchability.

[0012] The front and rear sections 6, 7 respectively carry on their circumferential middle regions first suspending flaps 20A, 20B. These flaps 20A, 20B are made of a flexible sheet 35 such as a nonwoven fabric, which is soft and agreeable to touch, or cushiony and spongy material such as a plastic film or polyurethane foamed sheet, or a laminate of the nonwoven fabric and spongy material. The first suspending flaps 20A, 20B have their base ends 35A joined by means of hot melt adhesive 37 to the inner surface of the peripheral edge region 16 of the waist-opening 9 and their free ends 35B hanging down toward the crotch section 8 to extend into the lower waist region 17. The free ends 35B are provided on their surface opposed to the inner surface of the main body 2 with first fastening means 39 comprising one component 36A of a pair of mechanical tape fasteners 36 such as loop and hook systems, which is available under the trade name of VELCRO, secured thereto by a suitable means (not shown).

[0013] The pad 3 comprises an absorbent panel 42 which comprises, in turn, a compression-molded mixture 40 of fluff pulp fibers and discrete particles of a water insoluble hydrogel with tissue papers 41 covering it. A topsheet 43 and a backsheet 44 cover upper and lower surfaces of the panel 42, respectively. Portions of the topsheet 43 and the backsheet 44 extending outward beyond a peripheral edge of the panel 42 are bonded together. With regard to such extensions, portions extending outward beyond longitudinally opposite ends of the panel 42 form a pair of second suspending flaps 18, 19 interposed between the front and rear sections 6, 7 and the first suspending flaps 20A, 20B, respectively. Surfaces of the second suspending flaps 18, 19 opposed to the first suspending flaps 20A, 20B are provided with second fastening means 51 comprising the other component 36B of the tape fastener 36 are secured thereto by a suitable means (not shown) and operatively associated with the respective components 36A of the tape fastener 36 such that components 36A, 36B may be releasably engaged together. The pad topsheet 43 is made of a liquid-permeable nonwoven fabric or a plastic film. The pad backsheet 44 is preferably made of a liquid-impermeable plastic film. An extremely thin plastic film covered with a nonwoven fabric to improve its strength as well as the touch of the film may also serve as the backsheet 44. A liquid-permeable nonwoven fabric may also be used to form the backsheet 44 so long as the panel 42 has a sufficient moisture holding capability.

[0014] FIG. 3 is an illustration of pants 1 separated along the heat-seal regions 11 into the front and rear sections 6, 7 and opened out from the position shown by FIG. 1 in the longitudinal direction as indicated by arrows P, Q in a plan view partially broken away. As shown, the pants 1 are opened also in the transverse direction and the gathers formed in the front and rear sections 6, 7 as well as in the crotch section 8 in FIG. 1 disappear as the pants 1 are opened in these two directions. The first suspending flaps 20A, 20B are provided adjacent their transversely opposite ends with component 36A of the tape fastener 36 and the second suspending flaps 18, 19 are provided adjacent their transversely opposite ends with the other component 36B of the tape fastener 36 operatively associated with the component 36A. The pad 3 is provided along its transversely opposite side edges with longitudinally extending elastic members 50, respectively, which are disposed between the topsheet 43 and the backsheet 44 and secured in a tensioned or stretched condition to the inner surface of at least one of these two sheets 43, 44.

[0015] In the pants 1 constructed as described above, the flexible sheet 35 for the first suspending flaps 20A, 20B as well as the topsheet 43 and the backsheet 44 of the pad 3 are preferably made of a soft material which is agreeable to touch and does not adversely affect the circumferential stretchability of the front and rear sections 6, 7. For bonding the first suspending flaps 20A, 20B to the main body 2 and for bonding the topsheet 43 and the backsheet 44 together, it is preferred to use soft type adhesive or to arrange intermittent bonding spots in consideration that these components should keep their softness. It is also possible to define the second suspending flaps 18, 19 by one of the topsheet 43 and the backsheet 44 if it is desired to improve the softness in these flaps 18, 19. As a criterion of softness, the first suspending flaps 20A, 20B and the second suspending flaps 18, 19 preferably have a stiffness of less than 150 mm as measured according to JIS P 8143. The presence of the tape fasteners components 36A, 36B increases the rigidities in the first and second fastening means 39, 51 relative to the first and second suspending flaps 20A, 20B, 18, 19 so that the presence of these first and second fastening means 39, 51 can be easily detected by the user's hand as it touches the first and second suspending flaps 20A, 20B, 18, 19 owing to the higher rigidities. If the rigidities of the first and second fastening means 39, 51 themselves are insufficient, such insufficiency can be compensated for by means of the rigidity of the adhesive used to bond the fastener components 36A, 36B to the respective first and second suspending flaps 20A, 20B, 18, 19.

[0016] In order to form the first and second fastening means 39, 51, the tape fastener components 36A, 36B may be replaced with pressure-sensitive adhesive. For example, the tape fastener components 36A or 36B may be replaced by pressure-sensitive adhesive tape fastener applied to their underlying member at the corresponding regions to form adhesive fastening regions and the other tape fastener components 36B or 36A may be replaced with relatively thick plastic film sheets bonded to their underlying members at the corresponding regions so that the adhesive fastening regions may be releasably fastened thereto. Instead of these pressure-sensitive adhesive and plastic film sheets, autohesion-type adhesive may be applied to both the first and second fastening means 39, 51 so that the respectively facing pairs of fastening regions coated with this autohesion-type adhesive may be separably bonded together. If the first and second fastening means 39, 51 can not obtain the desired rigidity merely by application of the pressure-sensitive adhesive and bonding of the plastic film sheets, nonwoven fabric or plastic film sheets may be additionally laminated on these fastening means.

[0017] In the inventive disposable absorbent undergarment, the first and second suspending flaps 20A, 20B, 18, 19 can be reliably fastened together over adequately large areas without being affected by the gathers formed in the elastic peripheral edge regions 16, since the first and second fastening means 39, 51 respectively provided on the first and second suspending flaps 20A, 20B, 18, 19 are more rigid than the first and second suspending flaps 20A, 20B, 18, 19 themselves, and extend downward beyond the elastic peripheral edge regions 16. Furthermore, such rigidity facilitates detection of the presence of these first and second fastening means 39, 51 and enables the pad to be smoothly mounted or interchanged.

[0018] The first fastening regions 39 are provided with their surfaces facing the inner surface of the main body 2 and, in addition, the first suspending flaps 20A, 20B are cushiony, so the first fastening means 39 give the wearer neither a feeling of incompatibility nor uncomfortable irritation, in spite of their relatively high rigidity.

[0019] The longitudinally stretchable crotch section 8 contracts in the longitudinal direction and therefore closely contacts the pad 3 against the wearer's crotch to prevent body fluid from leaking therefrom.