CA2104504C

CA2104504C - Disposable absorbent pants

Info

Publication number: CA2104504C
Application number: CA002104504A
Authority: CA
Inventors: Yoshihisa Fujioka; Hirotomo Mukai
Original assignee: Unicharm Corp
Current assignee: Unicharm Corp
Priority date: 1992-08-24
Filing date: 1993-08-20
Publication date: 1998-06-23
Anticipated expiration: 2013-08-20
Also published as: ES2117076T3; EP0585766A1; DE59308429D1; CA2104504A1; AU4465793A; GB2269998A; KR200150696Y1; CN2164815Y; GB2269998B; JPH0621621U; AU668970B2; EP0585766B1; GB9317594D0; GB2269998A8; JP2580182Y2; KR940005091U

Abstract

Disposable absorbent pants improved so that liquid excretion can be effectively prevented from leaking out along laterally opposite side edges of crotch zone. Front and rear bodies are placed one upon another and welded together along laterally opposite side edges as well as along the middle of crotch zone to form a basic structure of pants and there is provided an auxiliary liquid-absorbent panel over the top surface of the crotch zone.

Description

21 045~4 DISPOSABLE ABSORBENT PANTS
Background of the Invention The present invention relates to absorbent pants such as disposable diapers.
Pants type disposable diaper is well known,for example, from Japanese Patent Gazette No. 1992-42017.
Referring to Figures 10 and 11 of this patent gazette, this diaper of prior art comprises a laminate consisting of a liquid-permeable topsheet cut to be longer sideways, a liquid-impermeable backsheet also cut to be longer sideways and a liquid-absorbent panel sandwiched therebetween, and an elastic member extending along one of longitudinally opposite edges of the laminate around a waist opening as well as elastic members extending along the other edge around respective leg-openings, wherein said laminate is transversely folded in two, edges of the laminate thus folded opposite to the fold are bonded together and edges of cutouts formed at a middle position of the laminate's lower end are also bonded together so as to define a crotch zone.
While the diaper disclosed in the above-identified patent gazette provides a good fitting to the wearer's crotch because the diaper is formed in the crotch zone with the cutout so as to assure that the leg-openings are located below the bottom surface of the crotch zone, a central area of the crotch zone contains no liquid-absorbent panel and therefore it is difficult to prevent liquid excretion from leaking out along laterally opposite side edges of the crotch zone.

~. 28657-4 -Summary of the Invention Accordingly, it is a principal object of the invention to provide an improved pants type diaper comprising front and rear bodies separately formed and bonded together so that a liquid-absorbent panel covers also a bonding line in the crotch zone of the front and rear bodies.
To achieve the object set forth above, the invention resides in disposable absorbent pants comprising front and rear bodies each consisting of a liquid-permeable topsheet, a liquid-impermeable backsheet and liquid-absorbent panels sandwiched therebetween and assembled to form pants having a waist-opening as well as leg-openings, and circumferentially stretchable elastic members attached around the respective -~-oepn ~ characterized in that said front and rear bodies are separately formed, each of said panels being dimensioned so that said top- and backsheets have their outer peripheral edges extending outward beyond outer peripheral edges of the respective panels, the respective outer peripheral edges of said top- and backsheets being bonded together along the outer peripheral edges thereof, and the respective bodies are bonded together along the middle of their lower edges to define a crotch zone as well as along laterally opposite side edges, thus forming a basic structure of the pants; and an auxiliary liquid-absorbent panel curved in a U-shape is bonded at least at top ends of this U-shape to an inner surface of said basic structure in the crotch zone.

~ 1 04504 Preferably, said crotch zone defined by said convexly curved welding line is formed along its outer edges with a correspondingly curved cutout.
With the pants constructed according to the invention as outlined above, the crotch zone is reliably centered to the wearer's crotch and laterally opposite sides of the crotch zone cover at least inner sides of the wearer's thighs, respectively. The crotch zone also contains the liquid-absorbent panel and therefore liquid excretion is effectively absorbed also in this zone.
Brief Description of the Drawings The invention will be described by way of example with reference to the accompanying drawings, in which:
Figure 1 is a perspective view showing an embodiment of a diaper constructed according to the teachings of the invention; and Figure 2 is a sectional view taken along a line X-X
in Figure 1.
Description of the Preferred Embodiments Referring to Figures 1 and 2, a diaper's basic structure 1 generally comprises front and rear bodies 2, 3 assembled in the form Gf pants having a waist-opening 4 and a pair of leg-openings 5. Each of front and rear bodies 2, 3 comprises a liquid-permeable topsheet 6, a liquid-impermeable backsheet 7 and a liquid-absorbent panel 8 sandwiched between said top- and backsheets 6, 7.

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-Lower ends of front and rear bodies 2, 3 are formed at middle positions with cutouts 9 defining a crotch zone.
The front and rear bodies 2, 3 are welded together by heat or supersonic means along lines lla, llb extending parallel with the cutouts 9 and the laterally opposite side edges 10, respectively, so as to leave narrow edges of these cutouts 9 and opposite side edges not welded. A size, shape and curvature radius of the welding line llb may be appropriately selected depending on whether the diaper is for adult or for baby so far as the welding line llb is convexly curved toward waist lines of the front and rear bodies 2, 3 and at least inner sides of respective leg-openings 5 extend downward beyond an apex 16 of the convexly curved welding line llb.
Circumferentially stretchable elastic members 12, 13 are interposed between respective edges of top- and backsheets 6, 7 extending beyond the panel 8 around a waist-opening and leg-openings, respectively, and said edges are closed together by hot melt type adhesive or said welding means. Laterally opposite side edges of top- and backsheets 6, 7 extending beyond the panel 8 are also closed together in the similar manner.
The laterally opposite side edges and the lower edges around the respective leg-openings of the front and rear bodies are illustrated as extending neither parallel with nor perpendicularly to a vertical axis 14. These side edges may however extend parallel with the vertical axis 14 and these A"~;'i'~

21 04~04 lower edges around the respective leg-openings may extend perpendicularly to said vertical axis 14 within the scope of the invention.
The diaper's basic structure 1 is provided on the top surface of its crotch zone with an auxiliary liquid-absorbent panel 15 which is elongate longitudinally of the diaper's basic structure 1. The auxiliary panel 15 comprises a liquid-absorbent core 15a covered with liquid-permeable sheets 15b and is bonded at least at longitudinally opposite ends to the top surface of the topsheet 6 with means of adhesive so as to be curved in a U-shape. With the diaper's basic structure 1 being put on a wearer, the auxiliary panel is curved in a U-shape together with the diaper's basic structure 1. The auxiliary panel 15 is preferably bonded to the diaper's basic structure 1 in a manner such that the auxiliary panel 15 thus curved floats above the top surface of the basic structure's crotch zone and more specifically the curved auxiliary panel 15 has its outer bottom spaced by a distance S of at least 10 mm from the top surface of the basic structure's crotch zone. However, it is also possible within the scope of the invention to arrange the auxiliary panel 15 so that the bottom of the auxiliary panel 15 may remain in contact with the top surface of the diaper's crotch zone even in th~ curved state. The auxiliary panel 15 may have its bottom layer comprising a liquid-impermeable sheet and/or have stretchable side flaps extending from laterally opposite sides thereof without departure from the scope of the invention.

' 28657-4 Components of the diaper 1 may be made from materials commonly used in well known diapers. For example, the topsheet 6 may be made of nonwoven fabric, the backsheet 7 may be made of plastic film, the panel 8 may be made of fluff pulp mixed with superabsorbent polymer, the elastic members 12, 13 may be made of natural or synthetic rubber. The core 15a of the panel 15 may be made of fluff pulp mixed with superabsorbent polymer and the sheet 15b covering the core 15a may be made of nonwoven fabric, preferably stretchable nonwoven fabric.
With the diaper constructed according to the invention as described above, provision of the auxiliary liquid-absorbent panel over the crGtch zone allows the crotch zone to absorb liquid excretion sufficiently to prevent any liquid excretion from leaking along the laterally opposite side edges of the crotch zone.

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Claims

1. Disposable absorbent pants comprising a front body and a rear body, separately formed and bonded together to form a basic structure having a waist opening, two leg-openings and a crotch area extending between said leg-openings, and an auxiliary liquid-absorbent panel disposed within the basic structure between said front body and said rear body, (A) each said body comprising a liquid-permeable topsheet, a liquid-impermeable backsheet facing the inside of the basic structure and a liquid-absorbent panel sandwiched therebetween, (B) each body having spaced apart side edges that are bonded together to form spaced apart side edges of said pants that extend between each leg opening and said waist opening, (C) each body having bottom edges, portions of the bottom edges of said bodies being spaced apart from each other to form leg-openings and the remaining portions of the bottom edges of said bodies being bonded together along a concave welding line to thereby form a concave crotch zone that extends between said leg-openings, said concave crotch zone having an apex that is closer to said waist opening than its free ends, and (D) said auxiliary liquid-absorbent panel having a generally U-shaped configuration with the free ends of said U-shape facing towards said waist opening and being bonded to respective inner surfaces of said front and rear bodies, and a middle part of the auxiliary panel, when the pants are worn, floating above the top inner surface of the crotch zone of the basic structure and being spaced therefrom by a distance of at least 10 mm.

2. Disposable absorbent pants according to claim 1, wherein said crotch zone is formed along its outer edge with a correspondingly shaped cutout.