This invention relates to a disposable pull-on diaper for absorption and containment of bodily wastes.
A disposable pull-on diaper is well known, which comprises a liquid-pervious topsheet, a liquid-impervious backsheet and a liquid-absorbent core disposed between these two sheets. These components are assembled together to form a waist-opening and a pair of leg-openings. FIG. 4 in the accompanying drawings is a sectional view showing an example of such well-known diaper. As shown, front and rear waist regions 106, 107 of a diaper 100 are put flat together and joined to each other along their respective side edges so as to form a waist-opening 111 and a pair of leg-openings 112, thereby to present a pants-like or brief configuration. Both the waist-opening 111 and the leg-openings 112 are provided along their peripheral edges with elastic members 113, 114, respectively, extending circumferentially and secured under appropriate tension thereto. FIG. 5 is a view similar to FIG. 4, showing the same well-known diaper as the elastic members 113, 114 have contracted. Referring now to FIGS. 4 and 5, movements of the diaper components before and after the elastic; members 114 for the leg-opening have contracted will be described with respect to the uppermost point 121 of the leg-opening 112. As will be apparent from this comparison, contraction of the members 114 causes a crotch region 108 of the diaper 100 to move upward together with a liquid-absorbent core 102. However, topsheet 103 and the backsheet 104 are joined to teach other by means of hot melt adhesive 116, 116A, provided at front and rear ends of the topsheet 103 and the backsheet 104 and provided immediately above front and rear ends 119, 120 of the liquid-absorbent core 102. Such arrangement disadvantageously restricts the liquid-absorbent core 102 against freely moving upward and, in consequence, forcibly crook the liquid-absorbent core 102 as seen in FIG. 5.
Once such crookedness occurring in the liquid-absorbent core has become permanent, a gap is left due to the permanent crookedness between the diaper put on the wearer""s body and the wearer""s skin. Such gap makes it difficult for the liquid-absorbent core to absorb body fluids discharged on the diaper as rapidly as possible. Furthermore, the crookedness of the liquid-absorbent core increases an apparent thickness of the diaper and makes the packaged diaper inconveniently bulky.
It is an object of the present invention to provide a disposable pull-on diaper having a liquid-absorbent core that is free from crookness or deformation.
According to the present invention, there is provided a disposable pull-on diaper having a front region, a rear region and a crotch region therebetween, the diaper comprising a liquid-absorbent core, a topsheet overlying the liquid-absorbent core and a backsheet underlying the liquid-absorbent core, the liquid-absorbent core extending across the crotch region into the front and rear waist regions, the front and rear waist region being joined to each other along side edges thereof to form a waist-opening and a pair of leg-openings; the waist-region and the leg-openings being provided with elastic members secured under tension thereto and extending circumferentially along peripheral edges of the respective openings; and the topsheet and the backsheet being joined to each other along the peripheral edges of the respective openings.
In such disposable pull-on diaper, the liquid-absorbent core has front and rear ends adjacent outer ends of the front and rear waist regions, respectively, defining together the peripheral edge of the waist-opening so that the liquid-absorbent core is restrained against a movement thereof relative to the topsheet in the front and rear waist regions as well as in the crotch region but freely movable relative to the backsheet at least in the front and rear waist regions; and the topsheet and the backsheet are not joined to each other at portions thereof extending outward beyond the front and rear ends of the liquid-absorbent core to the peripheral edge of the waist-opening.
According to one embodiment of the present invention, a portion of the topsheet extending outward beyond any one of the front and rear ends of the liquid-absorbent core to the peripheral edge of the waist-opening is tucked between the liquid-absorbent core and the backsheet.