AU672037B2

AU672037B2 - Disposable diapers

Info

Publication number: AU672037B2
Application number: AU48794/93A
Authority: AU
Inventors: Tsutomu Kido
Original assignee: Unicharm Corp
Current assignee: Unicharm Corp
Priority date: 1992-10-15
Filing date: 1993-10-05
Publication date: 1996-09-19
Anticipated expiration: 2013-10-05
Also published as: KR940009407U; GB2271501A; GB9321072D0; CA2107747A1; EP0593082A1; CN2171340Y; CA2107747C; JPH0634617U; JP2559053Y2; DE59308433D1; GB2271501B; KR200141299Y1; ES2117082T3; AU4879493A; EP0593082B1; TW418678U

Description

AUSTRALIA

Patents Act COMPLETE SPECIFICATION

(ORIGINAL)

rt"Y 7 Class Int, Class Application Number: Lodged: 9 9 9 999 9 Complete Specification Lodged: Accepted: Published: Priority Related Art: 9* *9 9 9 *9* 9* 9* 9 9 999* Name of Applicant: Uni-Charm Corporation Actual Inventor(s): Tsutomu Kido Address for Service: PHILLIPS OT7 TONDE FITZPATRICK Patent and Trade Mark Attorneys 367 Collins Street Melbourne 3000 AUSTRALIA Invention Title: DISPOSABLE DIAPERS Our Ref 343269 POF Code: 1647/76530 The following statement is a full description of this invention, including the best method of performing it known to applicant(s): -1A- DISPOSABLE DIAPERS BACKGROUND OF THE INVENTION This invention relates to disposable diapers.

It is well known to provide disposable diapers with side flaps extending between longitudinally opposite ends of such diapers and adapted to rise on the topside of such diapers as they are put on a wearer so that a quantity of body fluids may be effectively prevented from leaking through leg openings of such diapers. Such technique is disclosed, for example, by the specification of US Patent No. 4,704,116, according to which a liquid-permeable topsheet is partially folded so as to form sleeve-like flaps extending between the *too• longitudinally opposite ends of a diaper and elastic members e**e.

are bonded under tension longitudinally to these sleeve-like flaps so that these sleeve-like flaps may rise on the topside of the diaper as it is put on a wearer. Such a kind of technique is well known also from Japanese Patent Application Disclosure Gazettes Nos. 1988-105102 and 1988-112703, in accordance with which there are separately prepared a pair of sleeve-like members each having a length corresponding to the longitudinal dimension of a diaper and flaps are formed by bonding these sleeve-like members to the topsheet of the diaper. When the sleeve-like flaps or members are formed from a liquid-permeable sheet such as the topsheet, they are sometimes treated to obtain desired water-repellency to prevent body fluids from permeating therethrough.

Said flaps adapted to rise on the topside of the diaper as it is put on a wearer will be able to function in an expected manner so far as said flaps extend at least along the longitudinal dimension of a crotch zone. Nevertheless, the sleeve-like flaps or members according to the above-mentioned prior arts fully extend between the longitudinally opposite ends, the opposite waist lines of the diaper and portions c- these sleeve-like flaps or members lying adjacent said opposite waist lines are collapsed and bonded to the topsheet. Such an arrangement is obviously disadvantageous in that the zones adjacent the front and rear waist lines become bulky and stiffy, causing the wearer to feel uncomfortable.

Accordingly, it would be desirable to solve the problem as has been mentioned above without a loss of a body fluid damming effect of flaps by folding portions of top- and/or backsheets extending outward from transversely opposite sides of an absorbent core of a diaper to form the flaps adapted to rise on the topside of the diaper as it is -3put on a wearer so that said flaps should not be beyond a necessary extent substantially corresponding to the longitudinal dimension of the crotch zone.

SUMMARY OF THE INVENTION According to an aspect of the present invention there is provided a disposable diaper including a liquid-permeable topsheet, a liquid-impermeable backsheet and an absorbent core sandwiched between these sheets, said topsheet and/or said backsheet extending outward from transversely opposite side edges of said absorbent core, and further including elastic members bonded, under tension longitudinally of the diaper, to the respective portions of said topsheet and/or said backsheet extending outward from the transversely opposite side edges of said absorbent core at least along a longitudinal dimension of a diaper's crotch zone, said respective portions being folded along the respective elastic members so as to form folds projecting on the topside of the diaper and opposite inner sides of the respective folds being bonded together, wherein said folds with the opposite inner sides bonded together are not beyond a necessary extent defined longitudinally 30mm or more inside the longitudinally opposite ends of the diaper, '/VT O a/ ~f respectively, and have their projecting dimensions progressively increasing from longitudinally opposite ends of the respective elastic members toward the middle of the crotch zone so that these folds form flaps adapted to rise on the topside of the diaper within said necessary extent defined longitudinally of the diaper as said elastic members C.pe contract.

With the diaper of such an arrangement, the portions of the topsheet and/or the backsheet folded along the respective elastic members bonded thereto over the longitudinal necessary extent at least lying within the crotch zone form said flaps rising on the topside of the diaper over the extents defined between the longitudinally opposite ends of the respective elastic members as these elastic members contract. These flaps have their heights gradually decreasing from the maximum at the middle of the crotch zone toward the longitudinally opposite ends thereof.

BRIEF DESCRIPTION OF THE DRAWINEG The disposable diaper according to the ention will be readily understood more i etails from the following description Sy way of example in reference with the -4a According to another aspect, the present invention provides a disposable diaper formed from: a liquid-permeable topsheet; a liquid-impermeable backsheet; and an absorbent core sandwiched between the topsheet and the backsheet, the absorbent core having two spaced apart sides, the diaper including: a front body portion, a back body portion and a crotch zone intermediate the front body portion and the back body portion and terminating 30mm or more from the longitudinally opposite ends of the diaper; two spaced apart laterally extending first flaps formed from respective portions of the topsheet and/or the backsheet extending laterally outwardly with respect to each the side of the absorbent core and being located generally parallel to the sides of the absorbent core, the first flaps extending along respective opposite sides of the crotch zone; elastic members bonded under tension longitudinally of the diaper, to each of the first flaps; two spaced apart second flaps, each second flap; being located intermediate one side of the absorbent core and the e adjacent first flap, extending upwardly in a generally upstanding position which is generally at a right angle to a horizontal plane of the absorbent core, extending along the length of the crotch zone, having spaced apart ends that terminate at spaced apart locations of the crotch zone, having an elongated bottom of generally arcuate shape and an 25 elongated top edge that is substantially in a straight line, S(e) having a height which is greatest at its midpoint and which progressively and gradually decreases in height in both directions from the midpoint towards its spaced apart ends, and having a second elastic member in a stretched condition extending along the elongated top edge; D OG C:\WlNWORD\DELILAH\PGNODLET48794.DOC -a Lr j -4bwherein the length of each second flap corresponds to the length of the crotch zone; and wherein each second flap is composed of a portion of the topsheet and/or backsheet that has been folded upwardly in a generally closed U-shaped configuration.

In a preferred embodiment of the invention, portions of both the top-and backsheets extend outward beyond the side edges of the absorbent core to form the first and second flaps and the elastic members of the second flaps are located between opposite inner sides of the folded backsheet and intermittently bonded thereto.

In an alternative preferred embodiment, portions of both the top- and backsheets extend outward beyond the side edges of the absorbent core to form the first and second flaps and the elastic members are interposed between the top- and backsheets and intermittently bonded to at least one of the sheets.

In at least one particular form of the invention, only one of the topsheet and the backsheet extends outwards beyond the side edges of the absorbent core to the first and second flaps.

BRIEF DESCRIPTION OF THE DRAWINGS The disposal diaper according to the invention will be more readily understood from the following detailed description of particular embodiments made, by way of example, with reference to the accompanying drawings, in which: o DG C:\WVNWORDODELILAHPGNODLET548794.DOC Fig. 1 is a perspective view of a disposable diaper constructed according to the invention; Fig. 2 is a sectional view taken along a line A-A in Fig.

1; and Figs. 3A and 3B are views similar to Fig. 2 showing alternative embodiments of second flaps.

0 PREFERRED EMBODIMENTS OF THE INVENTION "ON" Figs. 1 and 2 illustrate a disposable diaper 1 in a perspective view and in a sectional view taken along a line A-A in Fig. 1, and Fig. 1 particularly illustrates a state in which the diaper 1 is curved toward the topside due to e contraction of elastic members 13, 18 as will be described later. The diaper 1 basically comprises a liquid-permeable C topsheet 2, a liquid-impermeable backsheet 3, and an absorbent core 4 sandwiched between these sheets 2, 3. The portions of said top- and backsheets 2, 3 extending beyond transversely opposite side edges 5 of the absorbent core 4 form first flaps 6 horizontally extending around respective leg-openings and second flaps 7 lying inside the respective first flaps 6 and adapted to rise on the topside of the diaper 1. The diaper 1 is longitudinally composed of front and back bodies 10, 11, and a crotch zone 12 extending between these -6front and rear bodies 10, 11. The first flaps 6 respectively contain said elastic members 13 having their intermediate sections extending along the longitudinal dimension for the crotch zone 12. The front and rear bodies 10, 11 are provided along their longitudinally opposite ends 15, 16 with elastic So. members 15A, 16A, respectively. These elastic members 13, 15A, 16A are interposed between the top- and backsheets 2, 3 and intermittently bonded under tension to one of these sheets. The second flaps 7 contain in their top edges 17 said elastic members 18 intermittently bonded under tension to the backside of the backshee-. 3. The rear body 11 is provided on transversely opposite side edges with tape fasteners respectively, each being bonded at one end thereof to the respective sicde edges.

In such an arrangement, the second flaps 7 are provided within a necessary extent defined 30mm or more inside the longitudinally opposite ends 15, 16 of the front and rear bodies 10, 11, and have their intermediate sections extending along the longitudinal dimension of the crotch zone 12. Each of the second flaps 7 is defined by a top edge 17 linearly connecting longitudinally opposite ends 21, 22 thereof under contraction of the elastic member 18 and a bottom edge 19 connecting said ends 21, 22 in a curved line. Said ends 21, 22 substantially correspond to the points at which the ends 18A, 18B of the elastic member 18 are bonded to the backsheet 3. The top- and backsheets 2, 3 are folded along the elastic member 18 toward the backside so as to form a fold having said top edge 17, and inner surfaces of this fold, areas of *e.

the backsheet 3 opposed to each other are intermittently *0 0 .o bonded together. The second flap 7 rises along said bottom edge 19 on the topside of the diaper as the elastic member 18 contracts and a distance between the top and bottom edges 17, 19 is a projecting height H of the second flap 7 in such a rising state.

*9 To obtain these second flaps 7, the elastic members 18 are bonded under tension to the backside of the backsheet 3 having no slack and then the elastic members 18 are *.es contracted by an appropriate amount so that the diaper 1 is r slackened like a bow with the elastic members 18 forming strings. After such a slackening, the top- and backsheets 2, 3 are folded along the full lengths of the respective elastic members 18 extending between the opposite ends 18A, 18B toward the backside by a width h (not shown) with the top edges defined by the respective elastic members 18 and the areas of the backsheet 3 opposed to each other are bonded together. Bonding the elastic members 18 to the backsheet 3 and bonding the areas of the backsheet 3 to each other are preferably made in an intermittent fashion in order to facilitate the elastic members 18 to contract easily. The width h of each fold corresponds to the height H of each second flap 7 and a location of the bottom edge 19 relative to the top edge 17 is determined in such a manner that the dimension h progressively increases from the minimum at the opposite ends 18A, 18B to the maximum at the middle of the crotch zone 12. In this way, the second flaps 7 can rise on the topside of the diiper 1 as the diaper 1 is slackened in a bow-shape and have "their projecting heights gradually decreasing from the maximum at the middle of the crotch zone 12 longitudinally toward the front and rear bodies 10, 11, e.s respectively.

Referring to and of Fig. 3, alternative embodiments of the second flaps 7 which are distinguished from that of Fig. 2 are illustrated in views similar to Fig.

2. Referring to the elastic members 18 are interposed between the top- and backsheets 2, 3 and intermittently bonded to at least one of these sheets 2, 3. Referring to on the other hand, the topsheet 2 is relatively narrow and terminates inside the respective second flaps 7, i.e., the second flaps 7 are formed only by the backsheet 3.

-9- Besides the second flaps 7 may be formed by any one of the top- and backsheets 2, 3. While the opposed areas of the backsheet 3 are illustrated as closely contacting each other, these opposed areas may be gradually spaced from each other toward the bottom edges 19 due to the intermittent bonding.

Referring to Fig. 1, portions of the top- and backsheets 2, 3 which extend outward beyond the periphery of the absorbent core 4 are water-tightly bonded to each other «6 around the absorbent core 4. The topsheet 3 may be made of nonwoven fabric or porous plastic film, the backsheet 3 may be made of plastic film and the absorbent core 4 may be of fluff pulp, a mixture of fluff pulp and superabsorbant 4 5- S polymer, or the like. Attaching and bonding in making the diaper 1 may be achieved by utilizing adhesive such as hot melt type adhesive, sticky glue, heat sealing technique, or the like.

According to the invention, a diaper is provided with flaps longitudinally limited within a necessary extent so that their intermediate sections extend along the crotch zone and adapted to rise on the topside of the diaper as it is put on a wearer so that these flaps have the maximum heights at the ;iddle of the crotch zone in which a quantity of excreted body fluids is apt to gather. Such an arrangement solves the problem that the portions of the diaper lying adjacent the waist line become bulky and stiffy, causing a wearer to feel uncomfortable, without loss of a body fluids damming effect.

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Claims

1. A disposable diaper formed from: a liquid-permeable topsheet; a liquid-impermeable backsheet; and an absorbent core sandwiched between said topsheet and said backsheet, said absorbent core having two spaced apart sides, the diaper including: a front body portion, a back body portion and a crotch zone intermediate said front body portion and said back body portion and terminating 30mm or more from the longitudinally opposite ends of the diaper; two spaced apart laterally extending first flaps formed from respective portions of said topsheet and/or said backsheet extending laterally outwardly with respect to each said side of said absorbent core and being located generally parallel to said sides of said absorbent core, said first flaps extending along respective opposite sides of said crotch zone; elastic members bonded under tension longitudinally of the diaper, to each of said first flaps; two spaced apart second flaps, each second flap: o being located intermediate one said side of said absorbent core and the adjacent first flap, extending upwardly in a generally upstanding position which is generally at a right angle to a horizontal plane of said absorbent •core, extending along the length of said crotch zone, having spaced apart .i 25 ends that terminate at spaced apart locations of said crotch zone, S. having an elongated bottom of generally arcuate shape and an elongated top edge that is substantially in a straight line, having a height which is greatest at its midpoint and which progressively and gradually decreases in height in both directions from said midpoint towards its spaced apart ends, and DG C;\WINWORD\DELILAHPGNODLE48794.DOC -12- having a second elastic member in a stretched condition extending along said elongated top edge; wherein the length of each second flap corresponds to the length of said crotch zone; and wherein each second flap is composed of a portion of said topsheet and/or backsheet that has been folded upwardly in a generally closed U-shaped configuration.

2. A disposable diaper as claimed in claim 1, wherein portions of both said top-and backsheets extend outward beyond the side edges of said absorbent core to form said first and second flaps and said elastic members of the second flaps are located between opposite inner sides of the folded backsheet and intermittently bonded thereto.

3. A disposable diaper as claimed in claim 1, wherein portions of both said top- and backsheets extend outward beyond the side edges of said absorbent core to form said first and second flaps and said elastic members are interposed d between said top- and backsheets and intermittently bonded to at least one of said sheets.

4. A disposable diaper as claimed in claim 1, wherein only one of the topsheet and the backsheet extends outwards beyond the side edges of the absorbent core to said first and second flaps. 25

5. A disposable diaper substantially as herein described with reference to Figure 1 in combination with any one of Figures 2, 3A or 3B of the accompanying drawings. DATED: 22 July, 1996 PHILLIPS ORMONDE FITZPATRICK Attorneys for: -UNI-CHARM CORPORATION DG C\WINWORDDELILAH'PGNODLETn8794.DOC -13- ABSTRACT There are provided a pair of projecting flaps inside longitudinally opposite ends of a disposable diaper 1 by a certain distance in order to make a wearer feel comfortable. Elastic members 18 are bonded, under tension in longitudinal direction of the diaper, to any one of portions of top- and backsheets 2, 3 extending beyond transversely 'opposite side edges of an absorbent core 4 so that these elastic members 18 lie within a necessary extent defined or more inside the longitudinally opposite ends 15, 16 of the diaper with the intermediate section of these elastic members S extending along a crotch zone 12. The topsheet and/or the backsheet are folded along the respective elastic members toward the backside between longitudinally opposite ends 18A, 18B of the respective elastic members and the opposed inner S4 a sides of the folds are bonded together, respectively, to form the flaps 7 adapted to rise on the topside of the diaper as it is put on a wearer. (cf. Fig. 1)