GB2271501A

GB2271501A - Disposable diapers

Info

Publication number: GB2271501A
Application number: GB9321072A
Authority: GB
Inventors: Tsutomu Kido
Original assignee: Unicharm Corp
Current assignee: Unicharm Corp
Priority date: 1992-10-15
Filing date: 1993-10-13
Publication date: 1994-04-20
Anticipated expiration: 2013-10-13
Also published as: JPH0634617U; ES2117082T3; GB9321072D0; KR200141299Y1; AU4879493A; KR940009407U; CN2171340Y; AU672037B2; JP2559053Y2; CA2107747A1; EP0593082B1; DE59308433D1; EP0593082A1; GB2271501B; TW418678U; CA2107747C

Abstract

Elastic members 18 are bonded, under tension in longitudinal direction of the diaper, to portions of a top-and/or backsheet 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 30mm or more inside the longitudinally opposite ends 15, 16 of the diaper with the intermediate section of these elastic members extending along a crotch zone 12. The topsheet 2 and/or the backsheet 3 are folded along the respective elastic members 18 toward the backside between longitudinally opposite ends 18A, 18B of the respective elastic members and the opposed inner 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. <IMAGE>

Description

1 2271501 DISPOSABLE DIAPERS This invention relates to disposable diapers.

It is well known to provide disposable diapers with side f laps 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 f luids 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 longitudinally opposite ends of a diaper and elastic members 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-l ke flaps or members are formed from a liquld- permeable sheet such as the topsheet, they are sometimes treated to obtain desired waterrepellency 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 f ar as said f laps extend at least along the longitudinal dimension of a crotch zone. Nevertheless, the sleeve-like f laps or members according to the abovementioned prior arts fully extend between the longitudinally opposite ends, i.e., the opposite waist lines of the diaper and portions of 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 stiff., causing the wearer to feel uncomfortable.

Accordingly, it is a principal object of the invention 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 f orm the f laps adapted to rise on the topside of the diaper as it is lw 1:1 put on a wearer so that said flaps should not be beyond a necessary extent substantially corresponding to the longitudinal dimension of the crotch zone.

V The object set forth above is achieved, according to the invention, by a disposable diaper basically comprising 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 comprising elastic members banded, 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 f olds being bonded together, characterized by that 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, 1 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 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 f laps 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.

The disposable diaper according to the invention will be readily understood 1h more detail from the following description made by way of example with reference to the accompanying drawings, in which:

1 Fig. 1 is a perspective view of a disposable diaper constructed according to an embodiment of 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.

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 contraction of elastic members 13, 18 as will be described later. The diaper 1 basically comprises a liquid-permeable 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 1 front 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 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 backsheet 3. The rear body 11 is provided on transversely opposite side edges with tape fasteners 20, respectively, each being bonded at one end thereof to the respective side edges.

In such an arrangement, the second f laps 7 are provided within a necessary extent defined 3Omm or more inside the longitudinally oppositeends 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, i c 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, i.e., areas of the backsheet 3 opposed to each other are - intermittently 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.

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 contracted by an appropriate amount so that the diaper 1 is 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 banded 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 f ashion 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 diaper 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, respectively.

Referring to (A) and (B) 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 (A), 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 (B), on the other hand, the topsheet 2 is relatively narrow and terminates inside the respective second flaps 7, i.e., the second f laps 7 are formed only by the backsheet 3.

X Besides the second flaps 7 may be formed by either 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 banding.

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 around the absorbent core 4. The topsheet 2 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 f luf f pulp, a mixture of f luff pulp and superabsorbant 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 middle 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 stiff, causing a wearer to feel uncomfortable, without loss of a body fluids damming ef f ect.

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Claims

-11CLAIMS

1. Disposable diaper basically comprising a liquid permeable topsheet, a liquid-impermeable backsheet and an absorbent core sandwiched between these sheets, said topsheet and/or said backsheet extending outward beyond transversely opposite side edges of said absorbent core, and further comprising elastic members banded, under tension, to the respective portions of said topsheet and/or said backsheet extending outward beyond the transversely opposite side edges of said absorbent core at least along a longitudinal dimension of the 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 3Omm or more inside the longitudinally opposite ends of the diaper, 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 contract.

2. 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 and said elastic members are located between opposite inner sides of the folded backsheet and intermittently bonded thereto.

3. 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 and said elastic members are interposed between said top- and backsheets and intermittently bonded to at least one of said sheets.

4. Disposable diaper as claimed in claim 1, wherein the portions extending outward beyond the side edges of the absorbent core are formed of only one of said top- and backsheet, the other of said top- and backsheet terminating inside said portions.

5. Disposable diaper as claimed in any preceding claim, wherein said portions extending outward beyond the side edges of the absorbent core form flaps extending horizontally around respective leg-openings of said diaper on the outer sides of said folds.

6. 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.