AU641413B2

AU641413B2 - Disposable undergarment

Info

Publication number: AU641413B2
Application number: AU59858/90A
Authority: AU
Inventors: Takamitsu Igaue; Katsuhide Kuramoto; Hironori Nomura; Tohru Sasaki
Original assignee: Unicharm Corp
Current assignee: Unicharm Corp
Priority date: 1989-08-10
Filing date: 1990-07-25
Publication date: 1993-09-23
Anticipated expiration: 2010-07-25
Also published as: EP0412549A1; DE59006006D1; JP2672866B2; AU5985890A; GB2235125B; GB2235125A; CA2023038A1; KR960001477Y1; CA2023038C; EP0412549B1; JPH03162854A; GB9016959D0; KR910004009U

Description

AUSTRALIA

Patents Act 641413 COMPLETE SPECIFICATION

(ORIGINAL)

Class Int. Class Application Number: Lodged: Complete Specification Lodged: Accepted: Published: Priority Related Art: r 1 u S- Applicant(s): Uni-Charm Corporation 182, Shimobun, Kinsei-cho, Kawanoe-shi, Ehime-ken, JAPAN a

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4 ^a Address for Service is: PHILLIPS ORMONDE FITZPATRICK Patent and Trade Mark Attorneys 367 Collins Street Melbourne 3000 AUSTRALIA Complete Specification for the invention entitled: DISPOSABLE UNDL~06e.C4R-ALM Our Ref 182682 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 DISPOSABLE UNDERGARMENT BACKGROUND OF THE INVENTION The present invention relates to a disposable undergarment and, more particularly, to a disposable undergarment such as open-type diaper, diaper in the form of underpants or briefs (inclusive of diaper for incontinence) or so-called infant training underpants.

It is well known to provide such undergarments, for example, in the form of underpants or briefs, particularly said infant training underpants with suitable elastic members around the respective leg-openings as well as around a waist-opening and with an absorbent core sandwiched between water-permeable top- and backsheets.

Conventionally in such undergarments, both the topand backsheets have not been elastic at all or, even if they are somewhat elastic, the elasticity has not been sufficient for the undergarments to be reliably put on the wearer's body to provide a good fitness.

In view of a fact that the top- and backsheets preferably should be air-permeable, these sheets have usually been made of nonwoven fabric and, with a consequence, it has been inevitable that a quantity of S; 25 liquid excretion once absorbed by the absorbent core 9* i partially leaks even if the core is interposed between the a* 99 99 9 9999 *99ooo -la sheets. Particularly in case of the infant training underpants, more or less leakage of liquid excretions might be tolerated for the particular purpose of such underpants and for this reason the problem of leakage has often intentionally been left as it is. However, it is undesirable that a plenty of liquid excretions leak immediately after occurrence of the wearer's excretions although ad perfect prevention of such leakage .mifh-be required in this particular case.

*A primary object of the invention is to deal with an .0 antinomic relationship between the iact that it is preferred to use the top- and backsheets having good air-permeability, GoAer-a-nramem.rA as it has conventionally been for disposable a-e t and the fact that it is undesirable to use nonwoven fabric at least for the backsheet in order to minimize possible leakage of liquid excretions.

The object set forth ab ve is achieved, according to the invention, by utilizing el stic nonwoven fabric for the top- and backsheets, interposing elastomer film as an 0 elastic barrier sheet between the op-i and backsheets and intermittently bonding the barrier eet to at least one of the top- and backsheets.

-When the barrier shet is intern 0 hpiwRPn hp -nP-- 2 SUMMARY OF THE INVENTION According to the present invention, there is provided a disposable undergarment comprising an elastic water-permeable topsheet made of nonwoven fabric, an elastic water-permeable backsheet made of nonwoven fabric, an absorbent core sandwiched between the top- and backsheets, leg- and waist-elastic members laid along both sides of a crotch zone and respective ends of front and rear zones, and an elastic barrier sheet positioned between the core and the backsheet and intermittently bonded to at least the backsheet, wherein each of the legelastic members comprises a first submember and a second submember intersecting each other at predetermined points thereof distant from the ends thereof, and their end sections extending from the respective intersecting points to the respective ends are bonded to the inner surface of the topsheet and/or the barrier sheet while their intermediate sections between the respective intersecting points are positioned centrally under the core.

When the barrier sheet is interposed between the top- *e o*

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2a and backsheets substantially over the entire area thereof, it is preferred to provide the barrier sheet along both sides in front and rear zones with perforations serving as air vents.

U nAe r-Qa rmy ernk With the garmeants constructed according to the invention as has been mentioned above, the top- and backsheets as well as the barrier sheet integrally stretch and contract as the wearer's body moves. The barrier sheet apparently serves as the barrier blocking a quantity of body fluids against o leaking toward the outer surface of the garments.

SIf the barrier sheet is provided along both sides in 0 front and rear zones with perforations serving as air vents, e the air vents will assure desired ventilation even in the case that the barrier sheet is interposed between the topand backsheets substantially over the entire area thereof.

If the barrier sheet is interposed between the top- and o*e backsheets over an area being narrower than the area of the Obn 0 6sE r -rPP-4I 0 top- and backsheets but larger than _:ehcore, desired ventilation will be assured through the both side areas of the top- and backsheets not occupied by the barrier sheet.

Sbaksheets the u anwtity h betwee the topermet and backsheets, the quantity o uids having permeated -t.hrough t opshnet is absorbed by the core.

3 BRIEF DESCRIPTION OF THE DRAWINGS An embodiment of the invention is illustrated by the accompanying drawings, in which; Fig. 1 is a perspective view showing garments of the invention; Fig. 2 is an exploded perspective view thereof; Fig. 3 is a perspective view of a barrier sheet; Fig. 4 is a perspective view, showing by way of examply, elastic members sandwiched between a backsheet and *o the barrier sheet; 0e

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Fig. 5 is a perspective view showing a relatively S* 0* narrow barrier sheet; and Fig. 6'is a sectional view illustrating a manner in which the backsheet and the barrier sheet are bonded to each other.

PREFERRED EMBODIMENT OF THE INVENTION g** n Uf\erqrr n+ Referring to Fig. 1, a-rm-4a 1has leg-openings 2 and a waist-opening 3 respectively provided with elastic members to 4, 5. H- unAer4cre-e+ Referring to Fig. 2,1gazments 1 compriseSan elastic water-permeable topsheet 6 made of nonwoven fabric, an elastic water-permeable backsheet 7 made of the same nonwoven fabric, a mat- or sheet-like absorbent core 8, 4 elastic members 4, 5 extending around the leg-openings and the waist-opening, respectively, and an elastic barrier sheet 9 made of.elastomer film. The top- and backsheets 6, 7 define together with the barrier sheet 9 between their front and rear zones 10, 11 a crotch zone 12 having both side edges formed with notches 13, 14, 15. The barrier sheet 9 is bonded to the backsheet 7 over the entire area thereof by means of hot melt type adhesive or welding and Sthe core 8 is intermittently bonded to the top surface of the barrier sheet 9 by means of hot melt type adhesive or welding. Bonding between the core 8 and the barrier sheet 9 and bonding between the topsheet 6 and the barrier sheet 9 a may be achieved either by a plurality of dot-like bonding means 16 or by a plurality of intermittent lines each having a suitable length. As will be seen in Fig. 4, bonding between the backsheet 7 and the barrier sheet 9 may be also achieved by a plurality of dot-like bonding means 17 (See Fig. 6) or by a plurality of intermittentlines each having a o55 suitable length.

It is most preferable that the core 8 is bonded not to the barrier sheet 9 but to the topsheet 6 and the core 8, and the backsheet 7 and the barrier sheet 9 are intermittently bonded to each other, respectively. In this way, elasticity of the topsheet 6, the backsheet 7 and the barrier sheet 9 can be most efficiently utilized and a 5 hindrance of body fluid absorption by the core 8 can be aboided, which otherwise might occur due to partially floating up of the topsheet 6 from the core 8.

The barrier sheet 9 is provided along the both sides in its front and rear zones 10, 11 with fine air vents 18 (See Fig. It should be understood that these air vents 18 may extend also through the top- and backsheets 6, 7.

The leg- and waist-elastic members 4, 5 are laid along the notched edges 13, 15 of the topsheet 6 and barrier sheet 0o 9 as well as along both ends 19 of the front and rear zones e* 10, 11. Each of the leg-elastic members 4 comprises a first submember 4A and a second submember 4B intersecting each n<Ac~ tolrsn c~.s~l nt Sh e +s -PH- 'heht-e.a-) and other at oong n-jcennd Ahe ppnn. nd their eise sections 4A 1 4B 1 extending from the respective intersecting points to the respective ends are bonded by hot melt type adhesive to the inner surface of the topsheet 6 sees and/or the barrier sheet 9 along the notched edges 13, be'V-uee~n r pea\v \ner-se,-,^Aa po r while their intermediate sections 4A 2 4B~ are positioned centrally under the core without being bonded to snae-of the sheets. It should be understood that these intermediate sections 4A 2 4B 2 also may be bonded to anyone of said sheets. Each of the waist-elastic members 5 is bonded by hot melt type adhesive to the inner surface of the topsheet and/or the barrier sheet 9 along the associated end 19.

The topsheet 6 and the barrier sheet 9 may be bonded, 6 if necessary, by heat seal ultrasonic welding or hot melt type adhesive to each other along their outer edges. The top surface of the core 8 also may be intermittently bonded to the topsheet 6, if required. As indicated by a chain line in Fig. 4, it is also possible to sandwich the elastic members 4 between the backsheet 7 and the barrier sheet 9 and, in this case, said elastic members are preferably bonded to the backsheet 7.

S* The barrier sheet 9 shown by Fig. 5 has awidth .i corresponding to that defined between a pair of parallel chain lines 20 in Fig. 3, namely, the portions extending outside the respective chain lines 20 in 3 have been e cut off in the embodiment of Fig. 5. With such embodiment, the ventilation is assured through the both side areas of the top- and backsheets that are not occupied by the barrier sheet 9.

*004 OA lamination 21 thus constructed is folded along a longitudinally midde. portion and intermittently bonded together along the both side edges by heat seal or ultrasonic welding means 22 into the garments as illustrated in Fig. 1 so that these bonded side edges may be manually S torn open without effort.

It should be understood that the garments of the invention may be provided in the form of well known pen-type final product wthout being subjected open-type as final product without being subjected 7 to the heat seal means or ultrasonic welding means 22 and in such case the rear zone 11 (See Fig. 2) will be provided along both side portions with fastener means such as the tape fastener of well known art. -smaR es .there is The top- and backsheets 6, 7 may be made of nonwoven fabric which is elastic both in longitudinal and transverse directions, the core 8 may be a hot compression molded 9 mixture of fluffy pulp, water absorptive polymer particles and hot melt type fibre, the barrier sheet 9 may be made of :e elastomer film being elastic both in longitudinal and e transverse directions, and each of the elastic members 4, may comprise at least one string or ribbon of rubber or plastic film.

Furthermore, said nonwoven fabric used as material for the top- and backsheets 6, 7 is obtained preferably by carding heat crimped fibre having a weight perunit area of to 45 g/m 2 and a fineness of 0.5 to 3 d into web and heat-treating this web into a sheet. Preferred example of said heat crimped fibre is that supplied from Chisso Co., Ltd. in Japan under the trade name of "EP FIBRE".

According to the present invention, the barrier sheet interposed between the top- and backsheets both of which are made of elastic nonwoben fabric serves not only to block 8 leakage of liquid excretions but also to enhance a fitness of the garments to the wearer's body because the barrier sheet also has an elasticity and is intermittently bonded to at least one of the top- and backsheets so as to stretch and contract integrally with one or both of the top- and backsheets.

Even when the barrier sheet is sandwiched between the top- and backsheets over the entire area of these top- and backsheets, the air vents provided in the front and rear zones along the both sides of the barrier sheet well prevent *eo. the interior of the garments from becoming stuffy.

fitness serves, in cooperation with, as ing effect provided by the leg- a-aist-elastic members to further -laf fctvT- .i-h i qliiia eycretions leakage, The barrier sheet is made of elastomer film which is,

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6" unlike nonwoven fabric, substantially free from a rapidly *4 lowered contraction stress during stretching due to loosened fibre entanglement and disjointed fibre bonding, so said barrier sheet is very effective to maintain a desired Scontraction stress in the entire material of the.

;contraction stress in the entire material of the -*gaerJfi.

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Claims

1. A disposable undergarment comprising and elastic water-permeable topsheet made of nonwoven fabric, an elastic water-permeable backsheet made of nonwoven fabric, an absorbent core sandwiched between the top- and back- sheets, leg- and waist-elastic members laid along both sides of a crotch zone and respective ends of front and rear zones, and an elastic barrier sheet positioned between the core and the backsheet and intermittently bonded to at least the backsheet, wherein each of the leg- elastic members comprises a first submember and a second submember intersecting each other at predetermined points thereof distant from the ends thereof, and their end sections extending from the respective intersecting points to the respective ends are bonded to the inner surface of the topsheet and/or the barrier sheet while their inter- mediate sections between the respective intersecting points are positioned centrally under the core.

2. A disposable undergarment as claimed in Claim 1, wherein the barrier sheet is positioned substantially over the entire area thereof and, in the front and rear zones, the barrier sheet is provided along both sides with air vents. o: 3. A disposable undergarment as claimed in Claim 1 or Claim 2, wherein the barrier sheet is narrower thd*. the width of the top- and backsheet.

4. A disposable undergarment as claimed in any one of Claims 1 to 3, wherein a lamination constructed by the top- and backsheets, the barrier sheet and the core are folded along a longitudinally middle portion and bonded 35 together along the both side edges in front and rear zones thereof so that leg-openings and a waist-opening respectively having the leg- and waist-elastic members therearound can be defined. 10 A disposable undergarment as claimed in any one of Claims 1 to 4, wherein the core comprises hot melt molded mixture of fluffy pulp, water absorptive polymer particles and weldable fiber.

6. A disposable undergarment, substantially as herein described with reference to the accompanying drawings. DATED: 16 June 1993 PHILLIPS ORMONDE FITZPATRICK Attorneys for: UNI-CHARM CORPORATION 0e *0 0 00 a a 5800Z ^.~5800Z, -11--