AU705352B2

AU705352B2 - Disposable diaper having slope peripheral portion

Info

Publication number: AU705352B2
Application number: AU40753/95A
Authority: AU
Inventors: Yasushi Inoue; Tsutomu Kido
Original assignee: Unicharm Corp
Current assignee: Unicharm Corp
Priority date: 1995-01-13
Filing date: 1995-12-29
Publication date: 1999-05-20
Anticipated expiration: 2015-12-29
Also published as: DE59608401D1; EP0721768A2; AU4075395A; JPH08191851A; JP3345204B2; EP0721768B1; TW325679U; KR960026719U; EP0721768A3

Description

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AUSTRALIA

Patents Act COMPLETE SPECIFICATION

(ORIGINAL)

Class Int. Class Application Number: Lodged: Complete Specification Lodged: Accepted: Published: Priority Related Art: 6 e- Name of Applicant: 00 Uni-Charm Corporation Actual Inventor(s): Yasushi Inoue Tsutomu Kido Address for Service: PHILLIPS ORMONDE FITZPATRICK Patent and Trade Mark Attorneys 367 Collins Street Melbourne 3000 AUSTRALIA Invention Title: DISPOSABLE DIAPER HAVING SLOPE PERIPHERAL PORTION Our Ref 437612 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): -1-

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1- I 1/2 j S~ ~I _C DIAPER HAVING SLOPE PERIPHERAL PORTION DISPOSABLE DIAPER HAVING SLOPE PERIPHERAL PORTION @0 00 *o o 00 *a 0 *Q@0o 8so

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00 a as* 0 0. 0 a P 0 a. p 0 0 0 a a, a a The present invention relates to an improved disposable diaper and, more particularly, to an improved disposable diaper for the absorption and containment of urine and feces.

Conventional disposable diapers include a liquidabsorbent panel having a core compression-molded from a mixture of fluff pulp and superabsorbent polymer particles and a liquid-permeable sheet such as a tissue paper adapted to cover the core. For example, in a diaper disclosed in US Patent No. 4,636,207, upper and lower surfaces of an absorbent core are covered with upper and lower surface tissue papers, respectively. According to this known diaper, the lower surface tissue paper extends outward beyond longitudinally opposite ends of the core, then these portions extending beyond the ends of the core respectively is folded along the ends back onto the upper surface of the core so as to be bonded to the upper surface tissue paper. Both upper and lower surface tissue papers have their widths narrower than that of the core and therefore the transversely opposite side edges of these tissue papers lie inwardly of the core's lateral side edges. A liquid-absorbent panel having the core covered with the upper and lower surface tissue papers 42, 1 r if ii lr t Leq7 S4 S

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2 in this manner is then covered with a liquid-permeable topsheet and a liquid-impermeable backsheet. The upper and lower surface tissue papers are bonded to the core, respectively, and bonded also to the top- or backsheet in order to prevent the liquid-absorbent panel from shifting relative to these top- and backsheets.

00 co °0 In US Patent No. 4,681,579, a diaper includes a liquid- *e absorbent panel having a core covered with a single tissue 0o paper continuously wrapping the core along its upper surface, 0000 o one of its laterally opposite side edges, its lower surface and the other of its transversely opposite side edges. Also in this diaper, the tissue paper is in close contact with the 00 .000 transversely opposite side edges of the core.

go 6 The arrangement of the core covered with the tissue 0 00 paper(s) disclosed in the above-mentioned literatures is certainly effective to prevent the core from deformation at *0 its transversely opposite side edges, longitudinally opposite ends and the sites closely covered with the tissue paper(s).

However, it should be considered that the core is often compression-molded from a mixture of fluff pulp and superabsorbent polymer particles and has a relatively high rigidity. When the known covering means as above mentioned K are applied to such core, a peripheral edge of the core will i 3 be rather angular or sharp. The bonding means of the tissue paper(s) to the core as well as the top- or backsheet also will cause a stiff feeling and often deteriorate the level of comfort of the wearer.

In view of the problems as described above, it would be desirable to solve such problems mainly by bonding flat together first and second liquidabsorbent sheets covering upper and lower surfaces of a core, respectively, along their peripheral edges outwardly spaced from a peripheral edge of the core at a desired distance.

SUMMARY OF THE INVENTION According to the present invention, there is provided a disposable diaper having a liquid-permeable topsheet, a liquid impermeable backsheet, and a liquid-absorbent panel having a liquid-absorbent core and first and second liquid-absorbent sheets covering upper and lower surfaces of said core, respectively, including: peripheral portions of said first and second liquid-absorbent sheets extending horizontally outward from a peripheral edge of said core being put flat together and bonded to each other at a desired distance from said peripheral edge of said core; wherein peripheral portions of said top- and backsheets extending *20 outward beyond said peripheral edge of said panel are bonded to each other so as to form an envelope; the peripheral portions of said first and second liqui. -bsorbe t sheets o**o are bonded between the peripheral portions of said top- and backsr 00 6 u 4 0 G it 4 :r :I rh~~y With the diaper constructed as described above, at least one of the first and second liquid-absorbent sheets defines a gentle slope between the peripheral edge of the core and the peripheral edges of the first and second tissue liquid-absorbent sheets bonded flat together at a desired distance from the peripheral edge of the core and said slope is effective to prevent the peripheral edge from becoming angular and stiff.

To prevent the panel from shifting relative to the top- and backsheets, the peripheral edges of the top- and backsheets are bonded together so as to form an envelope and the outer edges along which the first and second liquid- *0 O 0 *c 0 0 0I *004 t 0 1 14

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absorbent sheets are bonded together are horizontally placed against the inner side of the envelope or the first and second liquid-absorbent sheets are disposed between the peripheral edges of the top- and backsheets and these peripheral edges are bonded together.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a perspective view showing an embodiment of a disposable diaper according to the present invention, as partially broken away; Fig. 2 is a sectional view taken along a line II-1I in Fig. 1; Fig. 3 is a sectional view taken along a line 11l-Ill in Fig. 1; and Fig. 4 is a view similar to Fig. 2 showing a variant of the invention.

A disposable diaper according to the invention will be better understood from the following description with reference to the accompanying drawings.

Referring to Figs. 1, 2 and 3, a diaper 1 includes a liquid-permeable topsheet 2, a liquid-impermeable backsheet 3 and a liquid-absorbent panel 4 15 disposed between these two sheets 2, 3. The diaper 1 is provided along its transversely opposite side edges and along an upper end of a rear body with a pair of elastic members 5 for both leg-holes and an 0 S S 9 -1 I r I r 6 09 @0 o 4' *0D0 o r= 00.0 0090 0Q9 9 *0 0 99 0* 0 h #0 *0 elastic member 6 for waist-hole, respectively. These elastic members 5, 6 are bonded with a tension to an inner surface of the top- or backsheet 2, 3. The rear body is provided at transversely opposite side edges with a pair of tape fasteners 7 of well known art.

The top- and backsheets 2, 3 extend horizontally beyond a peripheral edge of a rectangular core 14 of the panel 4 and are put flat together and bonded by hot melt adhesive to each other at a distance from the peripheral edge of the core 14 so as to form an outer envelope 12 peripherally sealed.

The panel 4 includes the core 14 compression-molded from a mixture of fluff pulp and superabsorbent polymer particles and a liquid-absorbent upper surface sheet 15 made of tissue paper or nonwoven fabric and adapted to cover an upper surface of the core 14 and a liquid-absorbent lower surface sheet 16 made of tissue paper or fibrous nonwoven fabric and adapted to cover a lower surface of the core 14.

These upper and lower surface sheets 15, 16 are same-sized rectangular ones extending outward beyond the peripheral edge of the core 14 and being bonded flat together by hot melt adhesive at a distance from the peripheral edge of the core 14 to form an inner envelope 18. An outer edge of this inner envelope 18 is horizontally placed against an inner ili y

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side of the outer envelope 12 so that the panel 4 can not easily shift within the outer envelope 12. It should be understood that the core 14 may be intermittently bonded to the upper and lower surface sheets, if necessary, to prevent them from relatively shifting.

The top- and backsheets 2, 3 forming the outer envelope 12 and the upper and lower surface sheets 15, 16 define gentle slopes over the distances and from the peripheral edge of the core 14, respectively, preventing the relatively stiff side edges of the core 14 from biting into a wearer's skin. A relation between the distance and the distance may be so far as they are measured at a same site. Values of these distances may depend on the respective side edges and longitudinally ends.

Referring to Fig. 4, in the diaper 1, the peripheral edges of the upper and lower surface sheets 15, 16 are disposed and bonded between the peripheral edges of the topand backsheets 2, 3 put flat together to ensure that the panel 4 can not shift relative to the top- and backsheets 2, 3. In this case, the upper and lower surface sheets 15, 16 also are preferably bonded to each other by a means of hot melt adhesive 17. This variant shown by Fig. 4 is different from the embodiment of Fig. 2 in that a relation is

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For the diaper 1 of the invention, the top- and backsheets 2, 3 as well as the upper and lower surface sheets 16 may be of materials usually employed in this technical field. The upper and lower surface sheets 15, 16 may include hydrophilic fibers mixed with a desired quantity of S* hydrophobic fibers in order to improve a body fluid I' ~diffusivity of these sheets.

With the diaper of the invention, the peripheral edge I..o of the core is neither angular nor sharp and comfortableness to wear the diaper is improved, since the upper and lower surface sheets extend outward beyond the peripheral edge of Sit:', t the core and are bonded flat together at a desired distance from the peripheral edge of the core.

1 The inventive diaper advantagaously makes it unnecessary to bond the upper and lower sheets to the top- and backsheets by a means of adhesive as has been required by the prior art and thereby realizes a soft touch of the diaper, since the outer edges of the upper and lower surface sheets are horizontally placed against the inner sides of the outer envelope formed by the top- and backsheets so as to prevent the panel from shifting relative to the top- and backsheets.

Claims

1. A disposable diaper having a liquid-permeable topsheet, a liquid impermeable backsheet, and a liquid-absorbent panel having a liquid-absorbent core and first and second liquid-absorbent sheets covering upper and lower surfaces of said core, respectively, including: peripheral portions of said first and second liquid-absorbent sheets extending horizontally outward from a peripheral edge of said core being put flat together and bonded to each other at a desired distance from said peripheral edge of said core; wherein peripheral portions of said top- and backsheets extending outward beyond said peripheral edge of said panel are bonded to each other so as to form an envelope; the peripheral portions of said first and second liquid-absorbent sheets are bonded between the peripheral portions of said top- and backsheets.

2. A disposable diaper according to claim 1, wherein said first and second liquid-absorbent sheets are made of tissue paper or fibrous nonwoven fabric.

3. A disposable diaper according to any one of the embodiments substantially as herein described with reference to the accompanying drawings. DATED: 12 March 1999 PHILLIPS ORMONDE FITZPATRICK Attorneys for: SUNI-CHARM CORPORATION 5 0 5 r K~ip40S3 9.&doc ABSTRACT In a disposable diaper a licnid-absorbent'panel (4) is disposed between a liquid-permeable topsheet and a liquid-impermeable backsheet wherein a liquid-absorbent core (14) is covered with first and second liquid-absorbent sheets (15, 16) and these first and second liquid-absorbent sheets (15, 16) are put flat together and bonded to each other at a desired distance from a peripheral edge of the core (14). or a 8r r* 'i i 0 a 0 4 i 1- L 9