CA2149144A1

CA2149144A1 - An absorbent article having separately attached side-flaps, and a method of manufacturing such an article

Info

Publication number: CA2149144A1
Application number: CA002149144A
Authority: CA
Inventors: Peter Ronnberg
Original assignee: Molnlycke Ab; Sca Hygiene Products Ab; Peter Ronnberg
Current assignee: Essity Hygiene and Health AB
Priority date: 1992-11-11
Filing date: 1993-11-11
Publication date: 1994-05-26
Also published as: EP0773762B1; EP0773763B1; CA2149143A1; GB2287396B; NZ257924A; SE9203372D0; ATE192323T1; HU9501360D0; AU5535794A; HU9501365D0; SK281394B6; GB9509023D0; GB2287396A; CZ119795A3; EP0773762A1; CZ285122B6; SK61195A3; US5674215A; GB2287395B; PL308956A1

Abstract

2149144 9410952 PCTABS00032 An absorbent article, particularly a diaper, has a central absorbent unit (1) which is comprised of an elongated absorbent body (2) enclosed between a liquid-permeable inner casing sheet (3) which lies proximal to the wearer in use, and a liquid-impermeable, outer casing sheet (4) which lies distal from the wearer in use.
The absorbent unit is provided along its longitudinal edges (9) with liquid-impermeable folds (6) which are upstanding from the inner casing sheet and which form side-leakage barriers. The article has a side-flap (18) on each side of the absorbent unit (1). The side-flaps (18), optionally with associated edge elastic (21, 23), are produced in the form of rectangular strips (10) completely separated from the absorbent unit (1) and are thereafter jointed thereto. A longitudinally extending edge-part (13) of each strip (10) is suitably folded double and the backwardly folded part (19) is joined to the outer casing sheet (3a, 4b or 4) of the absorbent unit (1) along a curved fastening line (21). When the diaper is to be used, the side-flaps (18) are pulled-out laterally, the length of this extension, and therewith the width of the resulting side-flaps (18), being dependent on the curved shape of the fastening line (21). It is therewith possible to produce a curved outer contour (16) of the diaper for conforming to the wearer's legs with side-flaps (18) which originally have straight edges (11, 12). The material from which the side-flaps (18) are made can be chosen quite independently of the inner and the outer casing sheets (3, 4), so as to avoid irritation of the wearer's skin while still fitting closely to the wearer's legs.

Description

WO94/1095~ 214 9 14 ~ PCT/SE93/00964 ~ 1 An Ab~orbent_Article_Havin~ SeParately Attached Side-Fla~s~ and a Method of Manufacturinq Such an Article The present invention relates ~o absorbent articles, such as diapers, incontinence guards, sanitary napkins and like articles, and in particular to an absorbent disposable article according to the preamble of ClaLm 1.

The curved outer contour desirable to adapt the side-flaps ~o the wearer~s legs so as to hold the absorbent unit correctly positioned, creates difficulties in manu-facture. When the casing-layer ~tarting material is in the form of a web of uniform width, the contour can be produced by clipping away edge-partsO The drawback with this method is the wastage that o~curs, this wastage increasing the co~ts of material and requiring separate handling of th~ wa~te to r~move it from the clipping ~tation during manufacture. Another problem is en-coun~ered when the ar~icle is to be provided with edge ela~ti~ along its outer ~ontour during the manufacture of the elastic ar~icl~, since:it i~ difficult to apply elastic elem~nts along a curved line when said elements .-concerned have the form of relatively broad bands which ~' are to be fastened to one:or both ~urfaces of the side-flaps or be~ween layers included ~herein.

In order to avoid these problems, it is proposed, for in~tance, in EP-A2-0,1450080, to form an upstanding fold of a centre part of each long side of a rectangular ' I`` diaper blank.`The fo1ds are folded-in over the àbsorbent body and glued ~o the inner casing sheet. In this way, ~: the centre par~ of the diaper, the crotch part, i~ given a narrower ~hap~ without ne~din~ to clip-out the contoux.
~dge elastic can be applied along the straight edges prior to forming the folds. However, this diaper has the : ~rawback that:the effective width of the absorbent body is reduced by ~he ovPrlying folds, in which the liquid-~,c,-',~;''`,`' '' :''''~-: ~'~'d~x~ll~ar ' ' ..... ~. .
, . . 1 ~
impermeable outer casing sheet is included. The folds may also cause an uncomfortable feeling when the diaper is worn.

Furthermore, US-A-5 061 261 discloses a diaper having a central absorbent unit, comprising a topsheet web, a backsheet web and an intermediate absorbent body. The topsheet and backsheet are mutuall~ joined laterally outside the absorbent body. The diaper has side flaps, which comprise a first portion formed by said iaterally extending parts of the topsheet and backsheet, a second web-like portion and a third folded portion. The second portion is bonded to the first portion laterally outside the absorbent body of the-absorbent unit, and the third portion is bonded to the second portion.
The laterally outer edges of the side ~lap~ have a curved contour formed by recesses therein, obtained by cutting. Such cutting either involves loss of material,:as discussed above, or necessitates~complicated-cutting-and ~oini~ng steps~during -;-manufacture. Furthermore, it is difficult to provide such recessed side-flaps with pre-tensioned edge elastication. -W094/lagS2 21~ 91 4 l PCT/S~93/00964 `) 2 Lmpermeable outer casing sheet is included. The folds mayalso cause the diaper to be feel uncomfortable when the diaper is worn.

The pres~nt invention is intended to avoid the aforesaid problems and to pro~ide an absorbent article which has a curved outer contour when in its position of use and which can be manufactured readily without waste and can be readily provided with broad edge elastic when so desired while, at the same tLme, avoiding a reduction in the active wid~h of the absorbent body when forming the curved outer contour.

In the case of kn~wn diapers that are pro~ided with side-flap~, the sheet material from either the inner or the outer casing sheet of the diaper, or from both sheets, i8 included in the ~ide-flsps. ~his cau~es l~mitatlons with regard ~o the choice of a material that will ~nsure that the ~ida-flaps do not irrLtate the wearer's skin and, at the same timel possess the elastic properti~s desired.
~ccordingly, a further object fundamental to the invention is that the material from which the side~flaps are made can be chosen quite independently of the mat~rials used in ~he inner and the outer casing sheets.
~5 According to the invention, the aforesaid problems are sol~ed with an absorbent article having the character-istic features set forth i~ the following Claim lo 30~ IThe invention also relates to a method of manufacturing ~uch an article, ~aid:method being characterized by the characteri~tic features set forth in ClaLm 11.

The invention will now be described in more detail with reference to the accompanying drawings, in which Figure 1 is a perspecti~e, sectional view taken on the line I-I in Figure 2 and shows part of a disposable diaper according .

W094/109$2 2 1 4 9 ~- 4 4 PCT/SE93/009~
.
) 3 to a first embodLment of the in~en~ion, said diaper being ~hown laterally ext~nded; Figure 2 illustrates that side of the diaper in Figure 1 which lies r~mote from ~he wearer în use, ssid diaper being shown outstretched in its longitudinal dire~tion to a flat state, and the left and the right halves of the Figure showing the diaper beore and after being extended la~erally; and Figures 3 a~d 4 illustrate a second embodLment of the invention in a manner sLmilar to Figures 1 and 2.
The Figures il}ustrate a di~posable diaper, which has a so-called hour~las~ ~hape in it~ u~e stat~. ~he diaper includes an ab~orbent unit 1 which comprises an absorbent body 2 which i~ enclo~ed between an inner and an outer :~
casiny sheet 3 and 4 respecti~ely. The casing sheet 3 is made of a liquid-permeable and soft sheet material, for instance a nonwov~n material, a~d is intended ~o lie pro~Lmal to the we~rer in use. The outer casing sheet 4 ~.
is made of a liquid-Lmp~nmeable material, such as plastic ~hee~ Por instance. The ab$orbent body 2 may, for in- -stance, include absorbent fibre material, such as cellu-lose fluff, to whi~h ~o-call~d superabsorbent material ~:
has been added. The absorbent body 2 is elongated and has ~wo mutually oppo~ing and mutually parallel longitudinal-ly ~xtending side edges 5, of which only one is seen in Figure~ 1 and 3 re pectiYely, these ~igures essentially showing one-quarter of the diaper.

In the case of the preferred embodLment illustrated in , 30 ~ l Figures 1 and 2, the oute~ casing sh~e~ 4 islfolded-up`at the side-~ges 5 of the absorbent body 2 and an edge-par~
4a of ~aid ~heet 4 rises up o~er the surface of the ~bsQrhent b~dy 2 at e ch edge 5. ~he inner casing sh~et 3 i8 formed with a fold 6 at each of the side-edges 5 of khe absorbent body, this fold embracing the upstanding edge-part 4a o~ the outer casing sh~et 4. The inner casing sheet 3 fvrm~ aboYe the edge part 4a a sieeve 7

2 PCT/SE93/009~

which extends in the longitudinal direction of the absorbent unit 1 and in which a pre-stretched elastic elemen~ 8, for ins~ance a ruhbex thread, extends. The folds 6 form standing barriers which pre~ent fluid leaking la~erally from the absorbent unit.

shown in Figure 1, the material in the inner casing shee~ 3 extend~ from the slee~e 6 down along the outside of the edge-part 4a and a lonsitudinally extending edge part 3a of said sheet 3 is folded-in beneath the absorb-ent body 2, outside ~he casing ~heet 4. Correspondingly, an edge-part 3b mutually o the ca~ing sheet 3 is folded~
in beneath the casing ~heet 4 from the other edge (not shown in Figure 1) of the absorbent unit 1. The edge parts 3a, 3b overlap and are joined together on t~e underside of the absorbent unit 1. The edge-parts thereby form outside the outer ca~ing sheet 4 a furthex outer ~asing sheet which comprises the same material as the inner casing sheet 3, whereby the diaper obtains an i~ 20 improved, unitary appearance and its out~ide is morspleasant to the touch. However, it is ~ot nece~ary for the inner casing ~h~et 3 to exte~d down along the fu~l outer side of the fold 6, and the fold configuration i}lustrated in Figure 3, in which the ouker casing sheet 4 lie~ freely on the outer ~urface of the diaper, can be : u~ed alt~rnaeively in the inv~ntive diaper embodi~nt illustr~ed in Figures 1 and 2.

~he fold lines between the lower part of khe fold 6 and ~ i the edge-psrts 3a, 3b, or the outer casing shee~ 4 w~en no edge~parts 3a, 3b are pre~nt, are straight and parallel and form lvng ~ides 9 of the absorb~nt unit 1, which in the preferred em~odLment has a rectan~ular shape.
` 35 : An elongated strip 10 of skin-friendly sheet material, F in~ance a breathable, vapour-permeable fibre :
.

WO94/10952 2 1 4 ~ PCT/SEg3/009~
) 5 material, so~called nonwoven material, having straight, parallel side-edges 11, 12 is placed adjacent each ~f the long ~ides 9 of the absorbent unit 1. A firs~ part 13 of the width of the ~trip 10 is located on the outside of the outer casing sh~et 3a, 3b. The other, remaining part 14 of the width of the trip 10 is located laterally outside the side-edge 9 of the absorbent unit 1~ Edge elastic or leg elastic is mounted along the outer edge 11 of the strip 10 in the form of a band 15, preferably alastic ma~erial ~uch as rubber, plastic foam, ela~tic nonwoven material or ~he like. The band 15 is folded around the side-~dge 11 and is fastened to both surfaces of the s~rip 10 adjacent the edge 11, for instance glued thereto. The band 15 may form outside the side-edge 11 a sleevelike fold lÇ in which an elongated elasticielement 17 can be mounted in a pre-stretched state. The outer part 14 of ~he strip 10 and the band 15 together form a diaper side-flap 18 which is located outside the absorb-~n~ unit 1.
j 20 . That part 19 of ~he first s~rip part 13 that li.es nearest the inner side-~dge 12 of the strip 10 is folded back through 180 about a fold lin~ 20 which, in the idle ox r~st stat0 of the ~iaper, extends parallel with the ~ide-i 25 edge 12 of the strip 10~ ThLs is shown in the left-ha~d part of Figure 2. The backwardly-folded part 19 is positioned between the remainder of the strip-part 13 and the out~r casing sheet 3a, 3b and is joined thereto, for in~tance glued or welded thereto, along a fastening line .i30 I 21 space~ r~m the side-edge 12. As will be ~een from ~he left ~ide of Figure 2, the fastening line ~ curved ~uch th~t its distance d from the fold line 20 is small-est at ~he transverse centre line of the diaper and great~st at the front and rear waist dges 22 and 23 of the diaper.

WO94/109~2 PCr/SE93/009~
2 ~ 4 9 !

The dia~er is provided with self-yripping tapes or burr fasteners, 24, 25 on i~s rear waist-edge 23. When the diaper is to be put on, the self-gripping tapes 24, 25 are gripped on both sides of the absorb~nt unit 1 and pulled apart and then passed around the wearer's waist and fastened across the wearer's stomach, so as to form a waistband 24, 25. The front end edge of the diaper is moved up o~er the stomach and the front corners of the diaper are gripped and pulled apart. The corner~, i.e.
the end~ of the side-flaps 18, ad~acent the front waist-edge 22 are provided with self-gripping strips 26, 27 which are c~plementary to the tapes 24, 25, such as ~o ~nable the strips to be fastened to ~he tapes. ~he waist-band and the ~elf-gripping tapes may be of an earlier known kind and are con~equently not shown or descri~ed in de'cail in this document.

A~ the ~ide-flap~ 18 are pulled apart la~erally in th~
: afore~aid manner, when putti~g on the diaper, the inner part 13 of the strip 10 and the fold line 20 mov~
laterally outwards towards the side e~ge 9 of the absorb ent unit 1. ~he movement of each point alon~ the fold line 20 is arrest~d when ~aid point reaches the fastening line 21O 5ince the inner part 13 of the ~trip 10 is folded double, the maxim ~ distance D moved by each point : along the fold line 20, and therewith each point along the outer-edge 16:of ~he side-flaps 18, is egual to twice the aforesaid distance d between the fastening line 21 and the old line 2~ at said point. To illustrate this, l that edge of the band 15;whi~h is located on theiouts~de of the outer part 14 of the strip 10 is xeerenced 28.
Indicated with a chain line 29 in the right-hand part of Figure 2 is the~position of said edge 28 when the diaper is extended longitudinally but not laterally, corr~spond-ing to the full straight line 28 ~hown in the left-hand part of Fi ~ re 2~ The afor~said maxi~um mov~ment pa~h D
is corre~ponded by the distance between the lines 28 and .

W094/lOg52 21491~ l PCT/SE93/009~
l 7 29 J wherein D = 2d for each line transversely across the diaper.

~he absorbent unit 1 of the exemplifying e~bodLment illustrated in Figures 3 and 4 is also provided with leakage barriers formed by folds 6 ha~ing an elastic element 8 mounted in an upper sleeve 7. In the case of ~he Figure 3 ~ odiment, however, the inner ca~ing sheet

3 i~ n~t drawn down along the full height of the fold 6 on the out~ide of the upstanding edge-part 4a of the ou~er casing ~heet 4 as in the case of the Fisure 1 embodiment~ ~ut terminate~ with a narrow edge-part 3c which ~xtends down fr the sleeve 7 through only a part of the height of ~he fold 6 and is joined, for instance glued, to ~he outside of the edge-part 4a.

In the case of the embodiment illustrated in Figure~ 3 and 4, the strips 30 are made of an ela~tic or plasti-cally deformable material and in their rest state have parallel edç~es 31, 32. A fir~t part 33 of the width of each strip 30 extends oYer ~he outside of the outer casing sheet 4 and i~ fastened thereto by means of a glu~
bead s: r a w~ld ~oin 34, which extend~ in a straight line paxallel wi~h the edge 32 of the ~trip. The o~her parts 35 of the strips 30 located outside the long sides 9 of the absorbent unit 1 form the diaper side-flaps 36, which in this cas~3 are totally formable.

Because the ~ide-flap~ 36 a~re made of an elas~ic or 30 I formable material, the side-flap~ will lie confo~mingly against the wearer's legs when extended, a:ld therewith hold ~he ab~orbent unit 1 in the desired po~ition. ~ow-ever, ~e s$de-flaps 36 may also be provided with further, separate edge elastic when ~o desired, for insta~ce an elastic thread along the outer edge 31 of the strip 30.

W094/lV9~2 PCT/SE93/009~
æ~4~4 ~hen manufacturing diapers or absorbent articles in accordance with the invention, the absorbent unit 1 is first produced separa~e~y p~r se and the strips 10 or 30 forming the respecti~e side-flaps 18, 36 are also pro-duced separateIy per se. When the side-flaps are to have separate edge-elastics 15-17, these elastics are mounted at this stage of the manufacturing process. The first, inner parts 13~ 33 of respective strips lB~ 36 are then joined, glued or welded, to the outer casing shee~ 4 of the absorbent body 1, either along a curved fastening line according to Figures 1 and 2, or along a ~traight fastening line according to Figures 3 and 4.

When manufacturing absorbent articles according to Figures 1 and 2, an absorbent unit is produced by en-closing absorbent material between a moving web of liquid-permeable ~heet material 3 and a moving web of liguid-impermeable ~heet material 4. The fold~ 6 which form the longi~udinally extending ~ide-leakage barriers are formed at the same tLme in this tage of manufacture, if so desired.

Separate ~rom the manufacture of the ab~orbent unit 1, there are formed from sheet material two moving side-flsp webs 10 whi~h are provided with edge elastic 15, 17. The tWQ side-1ap webs and the absorbent-unit web are then brought together. A first part 13 of the width of the ~eb located adjacent the side-edge of each ~ide-f~ap we:b 10 is fold~d double around a straight longitudinal ly ex !, i 30 i ! tendi~g fold~ line 20, ~ee the left-hand~part~of Fi~urell2.
The backwardly-folded part 19 is joined to the outer casing sheet 3a, 3b-or 4 of the absorbent-unit web 1 along longitudinally extending :Eastening line 21, wherein the di~tance:of:the fas~ening line 21 from the longitudinally e~te~ding ~ide edge 9 o~ the absorbent-unit web 1 is varied during manufactur~, ~o that ~he fastening line 21 becomes curved. That part o~ the ~ide-WO94/10952 2 1 ~ 914 4 PCT/SE93/00964 flap web-part 13 which is not folded back extends from the fold line 20 towards and beyond the longitudinally extending ~ide-edge 9 of the absorbent-unit ~eb 1 and there merges with a second, remaining width-part 14 of the side-flap web 10, which thus lies la~erally outside said side-edge 9.

Sepàrate a~sorbent ~rticles are cut from the thus produced, moving article web, ~y cutting the web transversely.

I

:

Claims

Amended claims

1. An absorbent article having an elongated absorbent unit (1) comprising a liquid-permeable first, inner casing sheet (3), which forms part of the inside of the article which lies proximal to the wearer in a worn state of the article, a liquid-impermeable second, outer casing sheet (4), and an elongated absorbent body (2) enclosed between said first and second casing sheets (3, 4); the absorbent unit having two opposing long sides (9);
the article further having along each of said long sides (9) a side-flap (18; 36) which is made of a strip of soft sheet material (10; 30) whose length is greater than its width, and which is separate from but joined to either one of said casing sheets (3, 4) and the outer contour (16, 11; 31) of which facing away from the absorbent unit (1) is curved in the worn state of the article, characterized in that each of said strips has a longitud-inally extending first part (13; 33) forming a portion of the width of the strip located adjacent the absorbent unit (1), and a longitudinally extending second part (14; 35) forming the remaining width of the strip located laterally outside the long side (9) of the absorbent unit (1);
that the first strip part (13; 33) extends in across the adjacent long side (9) of the absorbent unit (1) and is joined to the absorbent unit (1);
that the second strip part (14; 35) is extendible in the transverse direction of the strip from a first state assumed when the article is still unused to a second state assumed when the article is worn;
and that the transverse extension of the second strip part (14; 35) varies along the length of the strip (10; 30) so that in the worn state of the article, the strip obtains said curved outer contour (16, 11; 31).

2. An article according to Claim 1, c h a r a c t -e r i z e d in that the absorbent unit (1) is essentially rectangular and has parallel long sides (9).

3. An article according to Claim 1 or 2, c h a r -a c t e r i z e d in that adjacent to and along each of the long sides (9) of the absorbent layer (1), there is formed in the inner casing sheet (3) an upstanding fold (6) which encloses at least partially a similar upstanding edge-part (4a) of the outer casing sheet (4); and in that an elongated elastic element (8) is mounted in the fold (6) in a pre-stretched state outside said upstanding edge-part (4a).

4. An article according to any one of Claims 1-3, c h a r a c t e r i z e d in that said first part (13) of the strip (10) presents a part (19) which is folded back through 180° so as to be located between said remainder (13) of the strip and adjacent casing sheet (3, 4); and in that the backwardly-folded part (19) of the strip (10) is joined to the adjacent casing sheet (3, 4) along a fastening line (21) which extends generally along the side-edge (12) of the strip and is curved in accordance with the desired outer contour of the side-flap (18) of the article.

5. An article according to Claim 4, c h a r a c t -e r i z e d in that the strips (10) forming the side-flaps (18) extend over said second casing sheet (3a, 3b; 4) and with their backwardly folded parts (19) are joined (21) thereto.

6. An article according to Claim 4 or 5, c h a r -a c t e r i z e d in that each strip (10) has straight, parallel side-edges (11, 12) in its first state when the article is extended longitudinally.

7. An article according to any one of Claims 4-6, c h a r a c t e r i z e d in that the side-edges (11) of said second parts (14) of the strips (10) are provided with elastic elements (15, 17) therealong.

8. An article according to Claim 7, c h a r a c t-e r i z e d in that the elastic elements include elastic bands (15) mounted adjacent said side-edges (11) on at least one of the two surfaces of the strip (10).

9. An article according to any one of Claims 1-3, c h a r a c t e r i z e d in that said strips (30) are fastened to said outer casing sheet (4) along a straight fastening line (34).

10. An article according to Claim 9, c h a r a c t -e r i z e d in that the strips (30) are comprised of defor-mable material.

11. An article according to Claim 9, c h a r a c t -e r i z e d in that the strips (30) are comprised of elastic material.

12. A method of manufacturing an absorbent article, comprising enclosing absorbent material (2) between a moving web of liquid-permeable sheet material (3), to form an inner casing sheet, and a moving web of liquid-impermeable sheet material (4), to form an outer casing sheet, and thereafter mutually joining said webs to form an absorbent-unit web (1);
forming two moving side-flap webs from sheet ? terial (10;
30); joining (?1; 34) the side-flap webs to the absorbent-unit web (1); and cutting the thus formed combination of moving, mutually joined side-flap and absorbent-unit webs (10; 30-1-10; 30) transversely, such as to form separate absorbent articles, characterized by arranging a first part (13; 33) of the width of each said side-flap web (10; 0) adjacent a longitudinally extending side-edge (12; 32) of the web over a portion of the absorbent unit (1) enclosing said absorbent material (2) and joining said first web part (13;
33) to the absorbent unit within this portion; and arranging the remaining second part (14; 35) of the width of the side-flap web (10; 30) laterally outside the absorbent-unit web (1) such as to form side-flaps (?8; 36).

1?. A method according to Claim 12, c h a r a c t -e r i z e d ?? folding said first part (13) of the width of each side-flap web (10) double along a fold line (20) joi-ning the backwardly folded part (19) of said first web part (13) to the absorbent unit web (1) along a curved fastening line (21) extending generally in the longitudinal direction of the web (10); and arranging that part of said second web part (13) which is not folded back on that side of said backwardly folded part (19) which lies remote from the absor-bent unit web (1) such that said part will extend from the fold line (20) towards the side-edge (9) of the absorbent-unit web (1) and there merge with said second part (14) of the width of the side-flap web (10).

14. A method according to Claim 12 or 13, c h a r -a c t e r i z e d by mounting elongated elastic elements (15, 17) along the side-edges (11) of said second width-parts (14) of the side-flap webs (10) and thereafter joining the first width-parts (13) of the side-flap webs (10) with the absorbent-unit web (1).