CA2263048A1 - Sanitary napkin having an internal shaping component - Google Patents

Abstract

A sanitary napkin comprising a topsheet. a backsheet, an absorbent core. and a filament spring disposed intermediate the core and the backsheet. The spring provides elastic displacement of the topsheet relative to the backsheet and convexly shapes a body facing surface of the topsheet.

Description

WO95/171~9 PcT~s9~ 92 S~lT.~RY ~APKI~' HA\~ G .~ ~NTEL~AL SHAPr~G COMPOI~,E~T

FELD OF THE ~VE~TION
The present invention relates generally tO disposable absorbent articles such assanitary naphns and~ more panicularly~ to a sanitary napkin havin~ an internal sprin~
o for displacin~ and shapin~ a portion ofthe sanitary napkin.

BACKGROUND OF TEE I~IVENTIO~
Abso~ articles such as sanitary napkins, p~ ~1;1;n~ and incontinence pads are designed to absorb and retain liquid and other dischlu~,cs from the human body, and to prevem soiling of the body and clothing by such dis~ a ge5. It is generally dcsuable to provide abso~ ..l1 articles such as sanitary napkins which maimain contact with the body of the wearer when thcy are worn, and which co~ ru~lll as closely as possible to the body of the wearer. Such body co.lrulllullg capability is believcd to incrcase the effectiveness of the sanitary napkin by reducing the 20 pOsa-billly that menscs will travel around the p~.unct~r ofthc sanitary napkin and soil the wearer~s body and/or rlQthi-~5 ~~
There have been a number of recent efforts to provide sanitary napkins and other ~ articles with improved fit chara,l.,..;.l.cs. Such recent efforts are dcs_.ibcd in U.S. Patent 4,950,264 issued August 21, 1990 to Osborn, U.S. Patent5,007,906 issued Apri~ 16, 1991 to Osborn, U.S. Patent 5,197,959 issued March 30, 1993 to Buell Wllile the sanitary napkins d;~lo~d in these lcf~nees r~,plcs~
advanc~ .t~ in the art, the search for new and ~i~e,~ t ways of improving body contact has cu ~ cd It is ~,l"~ y dcs~able that the sanitary napkin rn~int~in contact with and cû.~-,.. to the body of thc wearer under tynanic conditions (when the wearer walks, sits, etc.). For i~n-~ce when the sanitary napkin is put on, the sanitary3~ napkin is sl ~je~ed to lateral co..lprl,ss;on by the upper po-l-ons of the wearer's thighs. The forces applied by the wcare.'s thighs gcn~ y tend to distort the shape of the sanitary napkin, reducing the size of the targa the sanitary napkin provides.
One attempt to control the effect of theu cG...~ .;,s,~e forces is ~icrlosed in UlC Patent Applic~l;ûn 2,168,612A, publiched~June 2S, 1986. The UK patent ~o ap~,li. a~-on d;s~,losPs a sanitary towel with a resilient insert po~;l;on~d within the core or adjacent to a face of the core that is intended to inhibit pc. .-lancnt distortion of the , 09~ lJ9 pCT~S9-~1J~92 3 towel The l~K application teachcs that the inse t resists lateral deforrnatlon Ot the samtar~ towel. but does not teach or disclose a sani~ar~ napkin ha~ln~ bod~
corLf~ ngpro~ ,cs.
It is also tesirable to provide a sanitarv naphn which CGnfGI 1115 tO the wearer s body while ~ ;ny the comfort ofthc wearer Acc~rd,r.~ly~ a dcs,.ablc sanitar-o napkin should ,. ~ a;A contact with the wearer~s body. yet be capable of repcatedelastic d~fl~ction to allow the wearer to co..~u~lably assume di¢~ posîtions and to pc.f~,.., di~Fc;~.~t activities.
Sanitary napkins are generally f~ct~n~d to the we~'t,'S under~arrnen~s bv adhesive or oth~ means. .MJV"~ n~ of the ~ 's ~nd~ ~...c.~t relative to the s weare~s body can result in the sanitary napkin shi*ing from the desired position It is tl~fo.c also deslrable to provite a boty co..Ço,....ng sanitary napkin with a ~"rc~ to ~~cu.~ in~ bet veen the bodv of thc wearer and the ~ .'sl nd ~ u.
It is therefore an object of an aspect of this invention to provide an 20 absorbent article, such as a sanitary napkin, which intercepts menses by conforming to the shape of the female urogenital region.
It is another object of an aspect of the present invention to provide a sanitary napkin having a convexly shaped body facing surface.
It is yet another object of an aspect of the present invention to provide a sanitary napkin having a spring for repeated elastic displacement of an absorbent core and a liquid pervious topsheet relative to impervious backsheet fastened tothe wearer's undergarment.
A further object of an aspect of the present invention is to provide a sanitary napkin having a non-absorbent internal spring disposed interrnediate anabsorbent core and a backsheet.
These and other objects of aspects of the present invention will be more readily apparent when considered in lcfclellce to the following description and when taken in conjunction with the accompanying drawings.

WO95/17~J9 CA 02263048 1999-03-09 PCT~S91/lJ~92 SI~ RY OF THE ~"V~'TIO!~
The present invention is an absorbent article. such as a sanitarv napkin The sanitary napkin of the present invcntion has a liquid pervious topsheet having a body facing surface~ a liquid impervious b~ cheet joined to thc ~opsheet, an absorbent core d-,l~oscd intermediate the topsh~t and the backsheet. and at least one o nonabsorbent spring disposed inte~...cdlate the abso,l,c.~1 core and the backsheet The spring provides Z-dirt~,lion elastic dicploc~ t~r ~ of a portion of the topsheet relative to the bnc~cheet. and convexly shapes a portion of the body facin~ surface of thc topsheet along a longinl~inql centcrline of the sanitary napkin The topsheet can be joined to the b~ch~t to provide in~l~pc~d~nl movement 15 of the topc~ ant the ~ bo ~ .nt core relative to the b j~~ch~et In one embodiment the sanitary napkin has at least one longitu~iinqlly e~ .1;ng pleat joining the topsheet to the ba-L Ch~ for cu.al olLng scp~Y alion of the to~sh~ from the b~~~Ch~t The spnng can co...~,~.sc a filament spring joinet to the abso.l...lt core at a first position w;~-~ ;d~ t with the lon~ inql cc.ltc. linc of the d-s~,c~ ~' e abso. L.~n~
20 article, and joined to the backsheet at laterally spaced apart pGsi~;on~ s~--Y-.~t~-.,aYly po~;~;oned with respect to the lon~nJ~Iinql cc.l~.,.Lnc. The filarnent spring can ha~re first and second legs tY..ngcd in an inverted V corlfi~ration as viewed aYong the longtudinsl ce.lt~.li,.c of the s. nitary napkin In one e-~l,o~ t thc filament spring can co..,p,;~c a plurality of closed loops ~.lull~tllcally ~ os~d with respect to the 2S lonE~t~ inslcc.a.lli.cofthe-bsol,c.-tarticle The filqm~nt spring provides a sanitary napkin having a first Z-direction caliper at a Z-direction co,..~ e load of about 2 grarns, ant a second Z-d-- e~l.on caliper at least 15 m 'lim~ s l~s than the first Z-du~,l,on caliper at a Z-direction co...prc~.~re loat of less than 100 grarns The filament spring can thereby promote 30 body cGrYru. -~ e and wearer comfort by ~ t~ ~ ~8 the topsheet in contact with the weare~s body, while providing relatively low fC_ lr~e to co...~ncs~.on of the sarlitary napkL~ in the Z-dircction The spring also provides a sanitary napkin having a lateral caliper of less than 10 millim~t~rs at a lataal co...~.rcss.~c load of 100 grams. The filament spring thereby permits the ~op~ ( and core to bc co.."~,cssed 3s laterally at rclatively low lateral load lcvels to p~.,.ole both wearer comfort and co. fu....a. ce of thc top ~h~ and core with the wearer's body in the labial, perianal.
and/or glutcal groove areas 3a In accordance with one embodiment, a disposable absorbent article having a longitudinal cent~rline and longit~ in~l ends joining first and second lateral ends comprises:
a liquid pervious topsheet having a body surface;
a liquid impervious b~r~h~et having a garment facing surface, the backsheet joined to the topsheet;
an absorbent core disposed intermediate the topsheet and the backsheet;
and a non-absorbent spring disposed intermediate the absorbent core and the backsheet for providing Z-direction elastic displacement of a portion of the topsheet relative to the backsheet.
In accordance with another embodiment, a disposable absorbent article having a longitudinal centerline and longitudinal ends joining first and second lateral ends comprises:
a liquid pervious topsheet having a body facing surface;
a liquid impervious backsheet having a g~rment facing surface, the backsheet joined to the topsheet;
an absorbent core disposed intermediate the topsheet and the backsheet;
and a filament spring disposed intermediate the topsheet and the backsheet for providing Z-direction elastic displacement of a portion of the topsheet relative to the backsheet, and for convexly shaping a portion of the body facing surface of the topsheet along the longitudinal centerline of the absorbent article.
In accordance with another embodiment, a disposable absorbent article having a longitudinal centerline and longitudinal ends joining first and second lateral ends comprising:
a liquid pervious topsheet having a body facing surface;
a liquid impervious backsheet having a garment facing surface, the backsheet joined to the topsheet;

3b an absorbent core disposed intermediate the topsheet and the backsheet;
and a spring disposed intermediate the absorbent core and the backsheet for providing Z-direction elastic displacement of a portion of the topsheet relative to the backsheet, the spring having a wet caliper reduction of no more than about 8percent.

In accordance with another embodiment, a disposable absorbent article having a longitudinal centerline and longitudinal ends joining first and second lateral ends comprises:
a liquid pervious topsheet having a body facing surface;
a liquid impervious backsheet having a garment facing surface; the backsheet joined to the topsheet;
an absorbent core disposed intermediate the topsheet and the backsheet;
and a spring disposed intermediate the absorbent core and the backsheet for providing Z-direction elastic displacement of a portion of the topsheet relative to the backsheet, the spring having a wet caliper reduction which is no more than about 20 percent greater than the dry caliper reduction of the spring.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is a top plan view of the sanitary napkin of the present invention with portions of the sanitary napkin shown cut away.

W09S/1~1~9 PCT~S9~/lJ592 Figure ' is a section view taken alone line 2-' of Fieure I which sho~s the sanita~ napkin of ~he present invention in a compressed confieuration Fi~ure, is a section view of the sanitary napkin of Fisure ' showin~ the sanitarv napkin in an extended configuration Fi~ure 4 is a partial p~ ,cc~ e view of a sanitary napkin of the present o invention in an eYtended configuration. with portions of the topsheet.
abso,l,~ core and bac~cheet cut away to show a filament sprine comprising two closed loops dicposcd .llte.lllcdiale the absorbent core and the ba~' cheet Figurc S is a partial p~.spc~ e view sirnilar to that of Figure 4 showing a IS filarnent spring co""".~,ng closed loops ove.la~p~-,g in a scissors-like configuration Figure 6 is a top plan vicw of a relatively long sanitary napkin of the present invcntion having a plurality of springs ~lic~oscd along the long~nldin axis of the sanitary napkin.
Figure 7 is a top plan view of a relativdy long sanitary napkin of the pre~sent invention having spnngs with di~ t cullr~,al;on,s d;.l~osed along the longitud:--l centerline of the sanitary napkin.
Fiure 8 is a s~h~ .ot;c illu~l-~ion of a ~,luss s~liO. of a sanitary napkin of thc prescnt invention ~;~oscd bctwecn two plates, and showing the method for mcasuring the lateral caliper of the sanitary napkin under a lateral colll~,l.,salve loat.
Fiure 9 is a scction vicw of a sanitary napkin ahO. ~lg the sanitary napkin in an e~ Acd configuration and having a filamcnt spring colll~JI;aing two scparate Icgs spaced apart from one anoth~ in thc lateral d.. ~lion Figure 10 i-a a graph of Z-d~ iùn force ver-us Z~,lion caliper of a sanitary napkin aa shown in Figure 7, ant as measured over spring 1 00B.

DFTAn Fn DESC~IPTION OF T~lF INVF~mON
3S Figures 1-3 illustrate a sanitar,v napkin 20 -~ di-lg to one c-.. bod;~. ~.,t of the ~' sr~s~ble ~ .a article of the present il,~..,ltion. Aa used herein, the terrn "abso,b~ article" refers to articles whjch absorb and contain body eY~ 5 More ~c~;r.~lly~ the term is i.~1~ndcd to include, but not be limited to, sanitary napkins.
p~ntiliners~ and ;nro~;n~rlce pads (articles worn in the aotch region of a garment) ~0 The term "dij"os~le" refers to articles which are ;,~ cd to be discarded after a single use rather than laundered or otherwise le -so, cJ or reused WO95/1,1~9 PCT~S9111J~92 The sanitarv napkin '0 comprises a liquid pervious topsheet '' havine a bod-facing surface '3 a liquid impervious bacL-cheet 24 having a earrnent facine surface 'S an absorbent core 26 interrnediate the topsheet '' and the backsheet '4~ and a spring 100 disposed interrnediate the abso,b?ul core 26 and the backsheet ~4 The sanitary napkin 20 has two longitu~linql ends 28 and two lateral ends 30 The sanitary napkin also has a lon5itu~inql ce.nc.linc 29 and a lateral centerline 31 As used herein the terrn "lonsitu~inql" rcfers to a line, axis. or direction eenerallv aligned with the vertical plane which bisects the ~ d;n5 wearer into left and rieht body halves The terrn "latcral" refers to a line, axis, or direction generallv p..~.n~ qr to the lonsitu-linql .Ihc.,lion and Iying in a plane generally parallel to the plane of the t -~L cheet 24 when the sanitary napkin is suppo. Ied in a generally fla~
configuration. as shown in Figures I and 2 The sanitary napkin 20 is typically longer in the loneinl~lin~' direction than in the lateral d~lion The "Z" dirc~.~.on refers to a line, axis. or direction which is p~.~cndic-llar to the plane of the ba~L Ch~t 24 when the sanitary napkin is su~,po, led in a generally flat configuration, as shown in Figures 1 and 2 (ie., perpendicular to both the lon~nJ~lirql axis 29 and thc lateral axis 31 when the sanitary napkin is supported in~a generally flat configuration) The Z~ ion is illustrated in Figure 3 The spring 100 provides Z-d,~ ion elas1tic l' sF'--~t~nt of a portion of the topsheet 22 along the lon~yt~ -' c~.,t~,.linc 29, and prefaably a portion of theabso,bc.ll core 26, relative to the backsheet 24 The spring 100 also p.cf~.~bly convexly shapes a portion of the body facing surface 23 of the topsheet 22 along~ the lotlyt~ ' --' centerline 29, as shown in Figure 3 The spring 100 thereby maintains contact of the top~h~l 22 with the weare~s body. and shapes the topsheet 22 to confo.... to the wearer's body, particularly in the labial, perianal, or gluteal groove 30 areas The spning 100 is d ~posed ;.~t-,.,..cdiate the backsheet 24 and the absorbent core 26 and preferably ~Isctjr-lly ~' ~pls~re~ and shapes both the topshc~l 22 and the core 26 At least a portion of the core 26 is thaeby biased into contact with thetopsheet 22 to receive body ~ t~s passing through the liquid pervious topsheet 22 The spring 100 preferably extends between the core 26 and the ba~ 21 and preferably li~s the core 26 from the backsheet 24 to provide a void space 130 The void space 130 extends in the Z~ ,~.on from the bacLcl~cct 24 to the abso,bcnt core 26 The void space 130 is desirable to ensure that the spring 100 is the only elanent providing ~ re to "s~ r'~nt of the top ,l-c~l 22 and core ~6 o toward the ba~Lchc~l 42, such as by a co,~ r~-;~e load 200 Alternatively, the . . .

W09S11~9 PCT~S9~11JS92 space between the backsheet '1 and the absorbent core '6 can be partiall~ or completel- filled with a matenal such as an absorbent By "Z-direction elastic displacement" of ~he topsheet ' ' relative to the backsheet ~4~ it is mcant that the topsheet ~ can be displaced relative to the ba~kcheet '4 in the Z-direction from a first relatively unloaded. extended o configuration having a Z-direction caliper Zl shown in Fi~ure 3. to a second co,.")rcsscd confisuration having a caliper Z2 shown in Figure 2 (such as bv a Z-direction co-..p,~s~ive load 200 shown in Figure 2) and that the spring 100 willrestore the sanitary napkin 20 to have a Z-d.-~ ~ tion caliper which is at least about 70 percent of the Z-Ju ~ lion caliper Z I upon removal of the co,-.~ ssive load when the 5 sanitary naphin is dry and has not been loaded with body e~d?t~-s The elastic ~i~pl~~ement of the top~llc~l 22 relative to the b7~ Ch~t 24 can be ~ .rcsscd by the di~..nce Zl-Z2 The procedure for measuring the dirnensions Z2 and Zl is dcs_,ibcd below Figures 4 and 5 show the sanitary naphin in the relatively u~ ar~e~ e~Jcd position, with parts of the topsheet 22, core 26 and ~ac~sh~t 24 cut away to show the spring 100 The topshc~l 22 and the bP-~h~t 24 are joined tcg_lheY ~~j~r - the lon~t~ ents 28 and along one or both of the lateral ends 30 As used herein the term "join" refers to the con~i~;on where a first member or cG--~pL~ ~ is ~r~ched or co.~c~l~d to a second ,-.~mba or co--~l-or.- -~1 either directly; or ir.dilccll~ wherc the 2s first "~ lt~. or cG~onc.~l is attached or c~ le~ to an ;,.lec.l;ale member orco..ml or.~ which in tum is attachet or con~ c~d to the second member or co...?on~.~t.
Exa nining the co,-~rofi~ of thc sanitary napkin 20 in more detail. thc topshc_l 22 is the co~ ~ncnt of the sanitary napkin 20 oriented towards and 30 contacting thc body of the wearer for receiving body eY~ ff The topsh~et 22 is liquid per~iou ant shoult be flexible and non-inritating to the shin As used herein the term flexible refers to mataials which are co,-~?l:--,t and readily co,~".. to the shape of the boty or respond by easily tef~"..ung in the p~scnce of external forces Prefaably the topsheet 22 is not noisy to provide d,s..ction to the wearer The 35 topshc~l 22 should be clcan in ~.pp~nce and somewhat opaque to hide the discharges c~ ed in the core 26 The tGp~h~t 22 should exhibit good strike-through and rewet characteristics.
pc.llulling bodily discharges to rapidly pcn~t"lte the tr~psh~(l 22 to the core '6 A
suitable top~hc~ l 22 may be made from a widc range of materials such as woven and o nonwoven ,nale. ~'r. poly"~.ic materials such as apertured formed thermoplastic films apertured plastic films ant hyd,ofo,.,.cd therrnoplastic films; porous foams.

WO9S/171~9 PCT~S9~ 92 reticnl~ted foams~ reticulated thermoplastic films. and thermoplastiC scnms Suitabie - woven and nonwoven matenals can be comprised of natural fibers (e ~.~ wood or cotton fibers), synthetic fibers (e.g. polymeric fibers such as polvester, polypropylene, or polyethylene fibers) or from a col.,~h~a~ion of natural and synthetic fibers.
o A prcf~ d topsheet 22 comprises an apertured fonned film. Suitable forrned films are described in U.S. Patent 3.929,135 issued Dece.llb~r 30. 1975 to Thompson; U S. Patent 4,3Z4,246 issued April 13, 1982 to Mullane et al., U.S
Patent 4.342,314 issued August 3, 1982 to Radel et al.. U.S. Patent 4,463,045 issued July 31, 1984 to Ahr et al., and U.S. Patcnt 5,006,394 issucd April 9, 1991 to 5 Baird;~hich patcnts-arc ~-.col~,o.a~c~ . by l~f -e,~c~. A prefc.l~d topsheet 22 CO~ Jfli_S an apertured formed film joined to a nonwovcn wipe acquiCitiQrl sheet. as tlicr,losed in U.S. Patcnt 4,950, 264 issucd August 21, 1990 to Osbom, ~L~,h p~t~
is ,nco- ~,era~ ~ hc~... by . ~,f~Lnec.
rhe ba~' ch~et 24 may be any flexible liquid impervious material, such as a polyolefinic film. The bnc~ch~t 24 pl~ ts d-scl~cs coU~tcd by the sanitary napkin 20 from soiling the wearer or the wcarer's rlothing The bar~cheet 24 can ~e a low density poly~lh;lcnc f~lm about 0.01 to about 0.05 millimcters in t~ f'S~ A
suitable poly~,lhyl~-c film is sold by thc Ethyl Corp., Visqueen Division, . s Model XP-39385, and by the Clopay Col~,o.alion of CU~ ;, Ohio under the d~signqtion 2s P18-1401.
The b. L'h~ 24 can be larg~ than the topsh~- ~ 22 and the rb~" U~ c~ore 26, and preferably p~.;ph~.olly circlu..s~;libcs the topsl~c~l 22 and the core 26. The bac~h~ 24 rnay cG...~J.;sc flaps 44 ~ g outwardly from each longin~-lin~ql edgc 28. The rdaps 44 may be made in accordance with the t '~in~ of U.S. Patent Nos. 4,589,876 issued May 20, 1986 to Van Tilburg and 4,687,478 issued August 18, 1987 to Van TUburg, ~h: ' p~ e incorpor~ by ._~ncncc. The backsl#ct 24 and thc flaps 44 may be unitary and co~ r~i~e. Altcrnatively, the flaps 44 can bc 3Cp& UC co--~ro,, .-~ joined to the ba~' Ch~t 24.
The garment facing surface 25 of the backshcct 24 may comprise an 3~ attachmcnt means 38 for securing the sanitary napkin 20 to the undc.4~ ,n~ of the wcarcr. ~fe.,oJ attachrncnt means 38 includc mechanical fasten~s, or more preferably, prcssure sensitive adhesive 38. The pressure sensitive adhesive 38 may be applicd to thc garmcnt facing surface 25 in one or more strips or patches. Asshown in Figures I and 2, the pressurc sensitive adhesive can be ~;cl~o5~ near the distal cnt of cach flap 44, as wcU as on a portion of thc b 7-"cheet 24 underlyin~ the W09~/171~9 PCT~'S9~/lJ59 topsheet '' and absorbent core '6 .~ suitable adhesive 38 is supplied as Centur~.~dhesive A30~-1V bv the Centur~ Adhesives Corp of Columbus~ Ohio.
The absorbent core '6 receives and contains body e~n~d~tes. panicularlv menses The core 26 should be flexible and no,u~ i"g to the skin~ and may have anv number of shapes including a rect~n~Jl~r or hourglass shape. The core ~6 has a o first face 40 oriented towards the bar~cheet 24, and a second opposed face 1' oriented towards the topsheet 22.
Suitable materials from which the core 26 can be madc include but are not limited to col"b-l-ations of airfelt, such as cell~lose wadding, and fibrated cornm~mition pulp; layers of tissue paper; and lbso l,c.lt gelling materials Examples of other suitable materials from which the corc can be made include meltblown polymers; foams; chemically 5~ c~ oAircd or cross-linked cell~los~c fibers; and synthetic fibers.
An eYernpl~y core 26 CO~ I.SCS a 1~ e of tissue paper and abso~ nt gelling material. Such a core 26 is d;sclos,~d in U.S. Patent 4,950,264 issued August 21, 1990 to Osborn, and U.S. Patent 5.007,906 issued April 16, 1991 to Osborn etal., which patent6 are incol~,or-~e~ b~ r~.~c for the purpose of t~ h~g a suitable construction for the core 26.
The core 26 and the topsh~t 22 are preferably joined tc&_~h~,~ to form a 15.~ lr so that the core 26 and the top jh~( 22 can be ~; r'a~ed by the sprin~ 100 as a unit. Thc second face 42 of the core 26 can be joined to the top'h'~ 22 by any suitable means, with an adhesive attachment being pi cf~ d. A suitable adhesive is a hot melt adhesive such as Findley Adhesive 2031 available from Findley Adhesives of Elmgrove, Wisconsin. Such ;,~ ;on of the to~ ~h~l 22 with the abso-b~.,t core 26 maintair~ contact between the top h~ 22 and the core 26 during wear, and pro~dcs capillary suction of the nuids passing through the topshccl 22 into the core 26.
The sanitary napkin 20 accold;l)g to the present i..~ ion has the core 26 and the associa~ed top~hc~ 22 d~oL~'ed from the backsheet 24 such that the topsheet 22 is joined to the ba~~ch~t 24 to provide ;.~A~ d~..1 Z~irection movement of the 3s top-hc~L 22 and the core 26 relative to the backsheet 24. A suitable sanitary napkin construction for pro~,iding such Z-d;-e~,tion decoupled motion of the top~h~ ~ 22 and the core 26 relative to the br-~ch~t 24 is ~is '~s~d in U.S. Patent 5,007,906 issued April 16, 1991 to Osborn et al.,~bich~ is i--;E~ d l~rçin ~y re~re~ce Such deco~Jp~ing is desirable to pennit the topslv~l 22 and the core 26 to be lifted by o ~he spring 100 into contact with the ~ body, while ~" ~.in~ the b~ t 24 to remain ~UChOfledtO the weare~s gannent by the attachment means 38.

WO9S/l?l~9 PCT~'S9~/lJS92 The sanitary naphn '0 can have a means for controllins the amount of Z-direc~ion separation of the topsheet '' and the associated core '6 from the backsheet '~ One suitable means for providins such control is one or more lonsitudinallv extending pleats 5' which form a connection joining the topsheet '2 to the backsheet 21 As used herein a '~lo~gitu~inqlly e~tP~'~Iing pleat" is a component of the sanitarv u napkin 20 having a longitudinally extending fold line 54 to provide one or more Z-direction layers of material along the fold line 54. Plcf,c. bly two lonsitudinallv eYtP~ ng pleats 52 are provided, one at each lon~itu~ --' end 28 of the sanitar~napkin 20 The longjtl~inqlly e~'c~ Q pleat 52 may be an e~ on of the topsheet 2~
5 an extension of the ba~L~I.e~l 24, or a sep~hale piece of material having one end joined to the topsheet 22 and one ent joined to the ba~~ch~et 24 The portion of the topsheet 2' which forms each pleat is folded unda a portion of the topsheet 22 laterally inboard of the longjturlin~l ends 28 and joinet to the ba;' ' e: 24 alons bond~ lines S6 Bond lines 56 can co"",~isc heat sealing or athesive bond lines 20 Bond lines 56 are preferably continllous to fonn a seal between the topsheet 22 and the bacL-ch~t 24, and can co..,~,.~ Iines of athesive bonding between the topsheet 22 and the b- ' Ch~t 24 The pleats 52 have a lateral width W (Figure 2) . s measured from the bond line S6 to the fold line 54 at a position lataaUy atjacent a spring 100 The width W
25 can be selectet to acco-.--.-o~ a desired arnount of Z-d~l.on l' ~p'-~cn~e~lt of the topsheet 22 relative to the backsheet 24 provided by the spring 100 The bond li,nes 56 ant the folt lines S4 can be generally paraUel, as shown in Figure 1. to accQ,.. state a equal arnount of Z~ue~,l.on d ~ ~en~ along the length of the sanitary napkin 20. Alterna~ively, the bond lines 56 or the folt lines 54 can diverge 30 or co..~ along the length of the sanitary napkin 20, as shown in Figure 6~ ton~odate tilI~.c.-l arnounts of Z-du~l.on ~' ~p'- -~~ent of the to~l.c~ 22 and core 26 along the length of the sanitary napkin 20.
The pleats 52 shown in Figures 1-3 are jQnc of the topsh~l 22 and c~ ,.;sc a single folt line S4 to forrn a C-shaped pleat. Alternatively, accordion-35 shapet pleats having a plurality of folt lines 54 can be u!~et. Above ~cf~,. cnced U SPatent 5,007,906 is inec.r~tct hcr~ b~ nce for the purpose of describing suita_le constructions for longjn~in~'ly e~r~ n pleats 52.
The top5h~l 22 may be le~ to the t?-L'Ch~t 24 at one or both lateral ends 30 to furtha acco...~od~ Z-dift~lion decoupling of the topsheet ~' o from the ba~ch~t 24. Leaving the topch~t 22 unattachet to the b?-' cheet ~4 atone of the lateral ents 30 further acco.~...,o~ s Z-di.~lion decoupling of the WO9~/171~9 PCT~'S9~/lJ~92 topsheet '2 and core '6 from the backsheet 21 .~dditionallv. Ieavin~ the topsheet 2' unattached to the backsheet at one of the lateral ends 30. such as at a rear lateral end 30B (Figure 6), also accomrnodates decoupling of the topsheet _' and core '6from the backsheet 24 in the longin~in~l direction Such lon~itudinal decouplin~
permits relative movement of the topsheet 22 and core 26 with respect to the lo backch~-et 24 (and the wearer~s undc~ga.,.,cn~ to which the b~cl~cheet is attached) in the plane of the sanitary napkin 20 The bt~ t, 24 must take on a radius of curvature dif~ from the radius of curvature of the ~opjhc.,l 22 and core 26 if the bac~chPet 24 is to stay attached to the wearer's und~r~ while the topsheet 2' and core 26 are in close co,~..,.ance with the wcarer's anatomy Longitudinal deco~pling of the topshcet 22 and core 26 from the b' ~L~hc~l 24. in con.1"na~ion with Z-dircction d~ourling of the topsh~l 22 and core 26 with respect to the bs-l-chee~ 24~ ~rco.,...,odst~s shear forces caused by this J;II~.cnce in radii of curvature Additionslly~ lon~ituAin~ s~ t;on of the core 26, as dts~-il,cd bclow, allows d;lle~cnl Z~ aion decouplir~g of the core 26 from the bac~ch-et 20 along the length of the sanitary napkin. Alternatively, lo~ytul ~-' decoupling can be provided by joining the topshc.,l 22 to thc backcl~t 24 at one of the lateral ends 30.
such as rear lateral end 30B, by a lataally e,~. di ~g pleat (not shown) to further ~ccG...,..od~e Z-d;~ ;on decoupling and to provide longitudinal decouplin~ of the topsheet 22 and core 26 with respect to the ba~L ch~ 24 in the plane of the sanitary 2s napkin 20 The cG-.~;nGd core 26 and to~she~l 22 laminate should be flexible in order that the body facing surface 23 of the to~ .h~,a 22 ant the second face 42 of the core 26 can be co..~ shapet by the spring 100. Thc1aminate of the core 26 and the topcheet 22 can thaeby cu-~fo--l- to the weare~'s body. In a "Icf~ ,d embo~liment the core 26 ant the to~ 22 have a co~~b~ed Taber bending stiffne~c~ as measuret in both the long~tndinsl and lateral di.~,~,l;ons, of less than about 3 0 gram-c~ -a~.,, and more preferably less than about 2.0 grarn~- ~ti -- t~,~ The Taber benting 5tiffness of a sample of the l~min~ of the ~opshc~ 22 and core 26 with dirnensions 3 8 cm (1.5 inch) wide and 3 8 cm (1 5 inch) long can be measured 3s ~cc~;ng to TAPPI mahot T 489 os-76 using a V-S Stif~ss Tester Model 150-B.
such as is available from Taber Instruments of the Teletyne Corp., North Talawanda.
New York The Taber bending stiffness in the longitudinal direa;on is cqlr~ q--ed by averaging at least lO rcadings taken from at least 5 samples Likewise, the Taberstifln~ss in the lateral d;l~,tion is cql~ul~q~ted using at least 10 readings taken from at least S samples The st~ sc test is conducted with a test range of 0-lO, a range weight of zero, and a 10 unit cG.,.l,c~ or weight The stif~ness tester rollers are WO9S/1~1~9 PCT~S9~ S92 mounted up to provide a test len~th of 1 0 cm (0 39 inch) Each sample has a vertically clarnped width and is deflected 15 degrees from a centerline position b-applying a bending load 1 0 cm (0 39 inch) from the clamps as measured in the longitudinal direction for the longit~din~l stiffness value. and as measured in the lateral direction for the lateral stiffness value Each sample is deflected in two o opposite directions using the 5tiffnr$c tester (e.g ~ first right~ and then leR) to provide 2 readings The average ofthe ,e"d gc is divided by thc co",r,~nsator weight (10)to obtain the Taber stiffness value in grarn-c~ "~ers The l~mjnqte of the topsheet 22 and the core 26, or a portion thereof, can be -lly worked or soften~ such as by roUing, to enhance its flexibility Suitable processes for ~, ~ y uo.king or rolling are dc~.il.cd in U S Patent4,107,364 issued to Sisson on August 15, 1978; U.S. Patent 4,834,741 issued to Sabee on May 30, 1989; U S. Patcnt 5,143,679 issued Scpt~ ~~ke~ 1, 1992 to Weberet al.; U.S. patent 5,156,793 issued Octobcr 20, 1992 to Buell et al; and U S Patent 5,167,897 issued Dcc~ .~brr 1, 1992 to Weba et al., ~at~ u are inc~ ed 20 ~ ~ by r~f In one c.~ho.J~ t the laminate of thc topih~l 22 ant the core 26 can CGlllpllSC at least one pair of longitudinaUy ~ di-~s hinge lines symrnetricallydi~rosed with respect to the longitudinal ax~s 29 Referring to Figure 6, the body facing surface 23 of thc topshc~ 22 is shown to have a pair of biconvcx hinge lines 2s 62 (shown as totted lincs in Figure 6) positioned latcraUy inward of a pair of biconcave hinge lines 64. The hinge lincs 62, 64 can include, but are not limited.to, lines of e..-~.~ .1 or compaction~ crcascs, score lincs or pre-fold lines Such lon~pt~ nally ~ ng hinge lincs 62, 64 facilitate the convcx shaping of the body facing surface 23 of the topsheet 22 when the sanitary napkin 20 is in the ~-n~ed position shown in Figure 3. The hinge lina 62 help the to~ 1 22 and the core 26 to c~,~,--- to the labia, p~ or gluteal groove, and the laterally outward hinge lina 64 help the top~hc~ ~ 22 and the core 26 to co.~,--- to the shape of the wearer's leg~.
In one c~ 1 the ability of the spring 100 to rcstore the Z-direction calip~ of the sanitary napkin 20 is relatively ~ cd by wetting of the spring 100Thc sprDg 100 can have a wct calipa reduction which is no morc than about 20 percent greater than its dry caliper reduction~ and a wet caliper redu~ion of no more than about eight percent. The wet caliper reductio)n and dry calip~ reduction for the spring 100 are measured using the foUowing procedure repeated for four spring ~o samples.

W0951171~9 PCT~59~ 592 The spring 100 is adhesivelv attached to a sheet of polvethvlene film ha~inQ a thickness of about I O rnil. The spring 100 and polyethvlene film are supported on the horizontal surface of an analytical balance, or other suitable scale The Z-direction caliper of thc spring 100 above the polvethylene film is measured usin~ a suitable ~ispl~cern~nt measuring system. A suitable displacement measunn~ svstemo is an ONO-SOKKI DG 3610 Digital Gauge and an O~O-SOKXI GS-503 Linear Gauge Scnsor available from the ONO-SOK~CI Co, ~IUI alion of ~apan. The Z-direction caliper of the spring 100 is measuret at various Z-direction load levels applied to the spring 100 through a circular load application foot having a diameter of 0.9S inch. The load application foot is COIu~C~,lCd tO the linear gauge sensor.
IS The spring 100 and polyethylene film arc placcd on the balance, and the balance is tared out to have a zero reating. The initial try Z-direction caliper of the spring 100 is mea'surct with the load appll~-l;on foot just touching thc spring 100. so that the balance ;~d;c~l~s a reading of about zero. The Z-direction load on the spring 100 is increascd to 32.1 grams in about 5 e~ual i..~ .l._nls, so that the balance 20 ~ re,ty S a weight of 32.1 grams. The load is then rernoved, ant the ~ ' ~a~de d dry Z-ion caliper of the spring 100 is rcco,ded with the load a~p~icntion foot jUSttouc~ling the spring 100, so that the balance indicates a reading of about zero. For each sarnple, the di~c~..nce b_t.c~ the initial dry Z-d--~,.,lion caliper and the u '~a'e~ dry Z-direction caliper is divided by the initial dry Z-direction caliper to 2s obtain the p~ .a~c change in dry caliper of the sarnple. The dry caliper reduction is the average of the p~ ta~5c change in dry calip~ for the four spring sr 1~ les ~
Each spring (ant its assoclat~d poly~..h~lcnc sheet) is completely sub-,l~.~cd in distilled wata for 10 s~con~s~ and then allowed to drain vertically for 10 scconds.
The spring 100 and poly_lh~lcnc sheet are then sup~.tcd on thc ho"Lulllal surface 30 of the anal~tical balance, and the bs'~ccd tared out to indicate a reading of zero.
The initial wa Z-direction calipa of the spring 100 is measured with the load a~plication foot just touc~-ing the spring 100, so that the balance ir~lc~lr5 a reading . of a~out z~o. The Z-dlrc~,lion load on the spring 100 is than i~l.,,~cd to 32.1 grams in about 5 equal inae.,._nls. The load is than removcd and the l~nio~d~ wet 3s Z~i-~lion calipa of thc spring 100 is ~~,co,d~d with the load arpli~ on foot jUSt to~l-;~ the spnng 100, so that the balance ;~-d;~ a rcating of about zcro. For cach samplc, thc diIL~lcc between thc initial wet Z-direction calipcr and the ded w~ Z-di.~_lion calipa is divided by thc initial wct Z-djJe~ljOn caliper tO
obtain the p_~ t~c change in the wet caliper of the sa nple. The wet caliper ~o re~ ctior ofthe spring 100 is the averagc ofthe pc.c.i.lt..~,C change in wet caliper for the four spring sarnples.

WO95/1~1~9 PCTQ~S9~ 92 In one embodiment. the spring 100 is nonabsorbent By "nonabsorbent i~ is meant that the spring 100 has an absorbency capacity of less than 100 percent The absorbencv capacity is the ratio of the weight of the water absorbed bv a dry sample to the dry sample weight. A nonabsorbent spring 100 is believed to have the advantage that its stiffness and/or its ability to displace the core upward are relatively o unaffected by body fluids en1~.ing the sanitary napkin 20 as co",pared to a spring which is abso.beut. The abs~.l.ency capacity of the spring is measured by first weighing the spring 100 to obtain its dry weight. and then co Fl~tely sub".c~5ing the spring 100 in distilled water for 10 SeCQll'lS ARer 10 seconds the spring 100 is removed from the water. The spring is then allowed to drain vertically for 10 5 secon~ls Water adhering to the surface of the spring is then removed by blotting the spring between two pieces of filter paper for 10 s~on~ls The spring 100 is blotted by placing a first piece of filter paper on a dry ho.izc ~Ital surface placing the spring on the first piece of filter paper placing a secont piece of filter paper on top of the spring to cover the spring and placing a piece of 0.25 inch thick Pl~.tglas wc,~5h;ng 20 0.26 pound on top of the second piece of filta papa to cova the portion of the second piece of filter pap~ overlying the spring. A suitable fil~a paper for blotting the spring 100 is filtration paper having a relatively smooth surfacc a particleret~ntion size of grea~a than about 20-25 mi~ t~.~ and a IIc.~be~ filtration speet of about 3~ secQr~c whae the ~ ~on speed is the time for 100 ml of 25 prefiltaed water to pass through a 10.0 square ~ r piece of filta paper with à
co~O~-t head pre~sure of 10 c~.-tb.,~ of wat~. A suitable filtration pape~ is Whatman 4 filtration paper manufactured by Whatrnan Ltd. of F.ngl~n-l and available from the Fisha Sci~ntific Corr~p~ny of Pittsburgh Pa. After blotting the spring 100 for 10 xcQn~lc the spring 100 is immetiately ue.ghcd to obtain the wet sample 30 wcight. Thc dry weight is sub~ ed from the wa weight to yield the grams of water absorbed by the dry sample. The pacentage 7~':.b~....,y capacity is oblaincd by tiviting the grams of wata ~.I,cd by the dry sample weight and multiplying the qlloti~nt by 100.
In a ~ref~ d c.--~i~ -1 the spring 100 is hy~l-.phob ~ A surface is 3s h~dr~phob ~ if the contact angle between a liquid ant the surface is greater than 90 degrees. The Amaican Chernical Society Pl~t-l~ ;o-~ "Contact Angle Wettability~
ant Adhesion " edited by Robat F. Gould and c~,t.,dhtcd in 1964 is i~o",o~
hore by ~ ~C for the purpose of showing how the contact angle can be determined.
~o In a pt~fe.t~ ~ ~~bG~ the spring 100 CG.. ~ CS a filament spring. By theterm "filament spring" it is meant that the spring 100 cu...~,riscs one or more slender WO9S/171~9 pcT~'S9~ 592 spring sections each sprine section ha~ine a leneth dimension L (Fieure ') at leas~
10 times. and preferablv at least l00 times its maximum cross-seCu~n dimension DEach spring section can compnse a plastic monofilament construcIion havine a eenerally round cross-sectiOn. such as a nylon monofilament with a diameter D ofbetween about 0 010 inch and about 0 10 inch, and more pl~f~ ~ably between abouto 0 015 inch and about 0 030 inch A generally round filarnent cross-section isde~ 'e to Plh,.;..~le sharp edgcs which could otherwise cause wearer discomfort.though other cross-sectionC can be used Suitable plastic monofilqmentc are con.J..~rcially available as 25 Ib and 40 Ib Berkiey TRLENE XT manufactured by the Berkicy Outdoor Technologies Group of Spirit Lake, lowa Referring to Figures 1-5, the filarncnt spring 100 can col.-prise a three dim~nrior~ql network when the sanitary napkin 20 is in the eYr~nded position shown in Figures 3-5 The spring 100 can CO~ J-;SC two lcgs 102 and 104, which are l,rcf~,, ~ly non-parallel as vicwed along the lon~tu ' - - ' axis of the sanitary napkin 20 when the sanitary napkin is in the ~ ndcd position The lcgs 102 and 104 can be 20 joincd to the absG-b-.lt corc 26 at a first position 111 along thc lon~n~lin~l c~,ltc~linc 29 of thc sanitary napkin 20 Thc Icgs 102 and 104 can bc joined to the b~ r'~~ 24 at laterally spaced apart sccond and thirt pGsi~;onC 113 and 115 rcipc~ ely The lcgs 102 and 104 can bc joincd to the abw- l,_.ll corc 26 at the first position 111 and to the bafkch~ 24 at the second and third positions 113 and 11525 by any suitable m~o~ rl-Jding but not limited to adhcsive bon~ling m~hqnicql bond;ng, ultrasonic bonding, and thcrmal bonding. Suitable adhesives for joining~the legs 102 and 104 to the bU~cl~ 24 and to the ?b~_ b_.lt core 26 include an adhcsive tapc avai~able from Anchor COl-~ 1. Inc., 3 Sigma Division. of Covington, Ohio, and Ccntury Adhesive A305-IV by the Century Adhesives Corp 30 of Col~mb~c~ Ohio.
In one ~ hod;-.lent the two legs 102 and 104 are formed from a continllouc piece of filunent. Alterna~vdy, the legs 102 and 104 can be ~)~alC pieces which arc spaced apart in the lateral dircction Figure 9 shows a spring 100 CO..l~ Sil g two separate pieces of fDunent formJng two luerally spaced apart legs 102 and 104 The legs 102 and 104 are joined tO the core 26 at laterally spaccd apart first positions I l lA and 11 lB"~ cly, and are joined to the b~-~ch~~ at sccond and third positiu. s 113 and 115, ..,_"c~ ely The second and third positions 113 and 115 are prefaably syrnrnetricallv po,it;o~lcd with respect to the longitu~ ql cent~.,Lnc 29 of the sanitary naplcin ~0 ~so The legs 102 and 104 can thereby form an inverted V shapc as viewed along the longit~u~in~' axis 29 when the sanitary napkin is in the ~ d position shown in WO9S/171~9 PCT~'S9J/I~9 Figures ~- j The inverted V shape of the le~s 10~ and 104 provides a tent t~rame-like structure which displaces the portions of the topsheet '~ and core ~6 alon~ the longitudinal centerline 29 from the b~cl~c~leet 4~, and convexlv shapes the bodvfacing surface 23 of the topsheet 2' alon5 the longinlclin~l centerline ~9 The legs 102 and 104 preferably form an inrl Ided angle A (Fisure 3) of between about 5 lo desrecs and about 85 degrees with a line parallel to the lateral centerline 31 when the sanitary napkin 20 is in the eYtended position shown in Figures 3-5 The less 10~and 104 pl~fe.ably form an in~l~)ded angle B (Figures 3 and 9) with the Z-axis of less than 90 degrees, and more preferably less than 60 dcgrecs The tent frame-like structure of the spring 100 is COu~pl~ 'b!e such that the legs 102 and 104 lie s~bs~r~ ly in a plane generally p~ 1 c~-lq~ to the Z-d.l~_lion undcr a co.l.pt~ci;.~e Z-d;lc~.lion load (e g Ioad 200), as shown in Figure 2, thereby reducins the angle A to about zao degrees The inverted V shape of the spring 100 can also provide additional Z-direction d~spl~ ent ofthe top~h~l 22 and core 26 relative to the b7-Lcheet 24 in Icsponseto lat~ally inward directed forces exated by the u~ a legs La~erally inward directed forces exerted by the ~ ~ . 's~ legs can cause thc portion of the legs 102 and 104 joined to the ~ Ch~~ 24 at the second and third pc~il;onc 113, I IS to move laterally inward (toward the lonE~ c~ t~ .c 29) relative to each other Such lateraUy inward movement of the leg 102 and 104 causes the inverted V shape of 2s the spring 100 to narrow in the lateral du~ .on. thereby reducing the angle B to about zero degrees. This lateral narrowing of the spring 100 causes the spring 100 to ~ ,f~ the force exerted on the core 26 and top she~ ~ 22 in the Z-direction The spring 100 can thaeby provite furtha Z-du~l.on ~isFl--~nlent of the topshc~ 2' and core 26 relative to the backsheet 24 when the sprhg 100 is colll~,lcssed laterally Such lataaUy inward l~O~ t of ~he legs 102 and 104 also pcrmits the topal-e~L 2'and core 26 to be co...~,l~cd to havc a relativdy thin lateral caliper at relatively low lataal load levels to p.u..-ole cG-~... ance of the top ,hc.,l and core with the wearer's body h the labia, perianal, and/or gluteal groove areas The leg 102 prefaably co...~,.;scs a first arcuate Y~ 1 103 e~l~n.1;n~
3s between the first position 111 and the second position 1 t3 The leg 104 preferably cû...~..iscs a secont arcuate YgJ. ~ 105 e~ t;-~g b~ en the first position 111 and the third position 115 The arcuate stu - ~ts 103 and 105 are symmetrically ~;~"G~d with respect to the lon~tJ~ cL.It~..li.lc 29 so that the spring 100 provides ~ ol .ng forces that are ayllul.~,l. ic with respect to the longitudinal ~o c~ lc 29 The arcuate sr~ t~ 103 ant 105 provite the legs 102 and 104 with fle~ihility to fi~~ilit"q~e the d~nc~;on of the spnng 100 from the e~ dcd position WO 95/1~ 9 PCrll,'S9'~/lJS92 shown in Fieure 3 to the compressed pOSItion shown in Fi5ure ' The arcuate segmen~s 103 and lOj also provide flexibility in the longitudinal direction~ andthereby perrnit relative loneitudinal motion of the topsheet ' and core 26 relative to the backsheet 24 The arcuate se~ --c -ls 103 and 105 pref~.ably subtend an angle of at least 90 lO degrees and more preferably an angle of at least 180 degrees. In one p.efe.. d embodiment each leg 102 CCi~ JIlSCS onc or more closed loops 106 joined to the core 26 and the b .~ ch~et 24 at .li ullc~ y opposcd positions 111 and 1 13 and each leg 104 co~ .iscs one or more closcd loops 108 joincd to the core 26 and the bac~cheet 24 at diarnetrically opposed poc;l;onc I I I and 1 15. The closed loops 106 5 and 108 pr~fe.~bly have a gcn~.ally circular or oval ring shape.
The Z-direction stiffness and thc Z-d.le~lion height of the spring 100 can be varied by varying thc size of the closed loops 106 and 108 and by varyins the latcral spacing of the pG :~ior.c 113 and 115 at which the closed loops 106 and 108 are joined to the backsheet 24. The Z~lirc~ lion 5t~ ss of the spring 100 will generally d~ ~ ledsc as the circu.. ,f~ . .1CC of the closed loops 106 and 108 is u.cle~. For a given cira,.l f .~nce of the loops 106 and 108 the Z-direction stif~ncss and the Z-d~l.on height of the spring 100 will dc~ . ~sc as the lateral spacing of the positions 113 and 115 is i.. ea-ed Thc closed loops 106 and 108 preferably have a circull~fe~nce of at least 5.1 cm (2.0 inch) and more llrefc~ably have a 2S circu.l fien nce of between a_out 7.6 cm (3.0 inch) and about 20.3 cm (8.0 inch). Thc closed loops 106 and 108 are prefaably joined to the b~ ch~t 24 at second and third positions 113 and 115 lc~pc~ Jy which are laterally spaced aput a distanceof b~ cn about 1.0 cm ant about 5.0 cm as ~..~l-d with the bP~ ~t 24 e ~ cd in a generally flat configuration~ as shown in Figure 3. A~d~ ;on~l1y. the Z-30 di.c~l,on Cliffn~ of the spring 100 can also be varied in other ways such as by valying the dimension D by va~ing the mate~ial from which the spring 100 is formed. and by providins multiple closed loops 106 and 108 to form the spring legs 102 and 104 ~_"c~ ely. The legs 102 and 104 can ovalap in a scissors-like cotfi~- ation as shown in Figure I and 5 to facilitate d~nc~l;on of the spring 100 3s from the ~ d~t position shown in Figure 3 to the co.,."-c3s~,;1 position shown in Figure 2.
The saniwy napkin 20 having a spring 100 with the legs 102 and 104 can be chara-~ in having a Z-du~l,on stiffilffs that d~re~:s as the Z-direction calipcr is dcc~c~scd from Z1 in Figure 3 to Z2 in Figure 2. The Z-d; e~ on stiffiness ~o is the change in Z- l; a ~ on force rcquired to produce a unit Z~ on displ~cenlent of thc top~hcel 22 relative to the ~a~ch~ 24. Without being limitcd by theoly. it is wo ss/~ s PC r~ss~ s2 believed that the resistance that the lees 102 and 104 provide to Z-direcuon cou.ples~ion decreases as the anele A (Figure 3) decreases Accordingly~ the wearer cornfort is maintained as the sanitarv napkin 20 is compressed from the extendedposition shown in Figure, to the coulpi~s3ed position shown in Figure ~ Of course, once the spring lO0 is flqttene~1. the Z-direction stiffness of the sani~arv o napkin 20 will increase with further displlcernent of the topsheet 22 relative to the backcileet 24.
Referring to Figure 6, a sanitary napkin 20 having front und rear lateral ends 30A, 30B can have a plurality of springs lO0 such as springs IOOA, IOOB. and IOOC
positioned along the longit~ inql axis 29. The springs IOOA-C are shown as dotted lines in Figure 6 and ue &langcd from the front to the rear ofthe sanitary napkin 20 I~,J~,c~ ely. The spring IOOA can provide co,~l - ~e of the topsheet 22 with thewearer's labial groove, the spring IOOB ean provido co"fo~ e of the topshe~l ~2 with the wearer's perianal groove, and the spring IOOC can provide confol",ance of the lopahc_l 22 with the weuer's gluteal groove.
As shown in Figure 6, the eore 26 can be se~ tcd to CGIl.~Jl;SC a plurality of core s~ 26A. 26B, and 26C whieh are ;..A~ ~d~ r d sF'~ le in the Z-direction. At least one spring lO0 can be associated with eaeh core ~ 26A-C
to provide lu~r~ Z-d.~e_~,on d ~pl~ ne~ of the core sc~ nlc 26A-C
relative to the b~-~ch~ 24. The adj~-~t core S~,5,~.--~t~, such as core sc~
2s 26A~ B and 26B, C ean be joined by laterally e.~ ;ng hinge lines 27. The hinge lines 27 can inelude, but are not lirnited to lines of e~ 1 or COI~
creases, seore lines or pre-fold lines. Alternatively, a1;~~nt eore se~ 26A~ B
and 26B, C ean be unattaehed, and are ir,du ~_lly joined to eaeh other by the topsheet 22.
A sanitary napltin 20 cGI~lpl;a~ng the filarnent spnng lO0 ean have a first Z-direction ealiper Zl at a Z-direetion cG~I~p~h~e load of 2 grams, and a seeond Z-tirection ealiper Z2 at a Z-duc~,lion cGll""~ e load of less than lO0 grarns, wh~ein the seeond Z-du~ ion ealiper is at least 15 ~ a less than the first Z-du.,~,lion caLiper Zl. More pr~fe.ably, the seeond Z-due.,l-on ealiper is at least 15 I--~ t~ra less than the first Z-direetion calip~ at a Z-direetion co"",re~ah~e load of less than 50 grarns. Even more prefe.~bly, the seeond Z-di,~_lion caliper is at least 15 millirnet~s less than the &st Z-direction caliper at a cu...~,.esa,~e load of less than 25 grams.
A sanita~ napkin 20 cG~ ;sing the filarnent spring lO0 ean also have a first ~o Z-dire~ion caliper Zl at a Z-di.e~lion cGIl~Jn~v_ load of 2 grams. and a second Z-du c~Lion ealip~ Z2 at least 25 m~ meters less than the firt Z-direction caliper Z I

W09511~1~9 PcT~s9~llJs92 al a Z-direction co",prcs~lve load of less than 100 grams More preferably ~he second Z-direction caliper is at least '5 millimeters less than the first Z-direction caliper at a Z-direction load of less than 50 grams The filament sprin~ 100 alsoprovides a sanitary napicin 20 having a Z-direction caliper of less than 10 milli~eters and preferably less than 5 milli~eters under a Z-direction compressive load of 90 lO ~rams The filament spring can thereby promotc body col.ru.lllance and wearer comfort by ~ ;ninQ the topsheet in contact with the wearer~s body while providing relatively low If ~ ce to cGI.~ saion of the sanitary napkin in the Z-direction A sanitary napicin 20 having the Slament spring 100 can have a lateral caliper of Icss than 10 m~ t~ ~ at a lateral cG.. prcss-~e load of 100 grams more plefc.abiy a laterai caliper of less than 5 ";~ "~t!, at a laterai CGIl.~J-C..Sl~C load of 300 grams and most p-cfe~ably a laterai caiiper of less than 3 millimeter5 at a cGI~ s~e load of 1000 grams The Slarnent spring th~eby permits the a portion of the topshc~l and core to be co...~rcss~d lateraily at rclatively low laterai load 20 levels. thereby plO.~-:)!;ng co.~lance of the to~ c~l and core with the wearer's body in the labia perianal and/or giuteai groove areas while ~; n~lt~rleol~cly un wearer comfort Figure 7 shows a sanitary napkin 20 having three filarnent springs forward spring IOOA middle spring IOOB and reanvard spring IOOC A sanitary napkin 20 2s having the spring confi~ation shown in Figure 7 was used to provide the data in Tables 1-.4. A d~sc--~J~ion of the filament springs IOOA-C and dcscli~,Lion of ~the procedure for ob~ ~ the data in Tables 1-4is provided below Refer~ing to Figure 7 the spring IOOA is spaced longitudinally a distance 13 1 of about 75 mrn from a forward lateral end 262 of the 'so 1,_.1t core 26 having a longitudinal length of a~out 23 cm (forward and lateral ends 262 and 264 are indicated in Fi~,ure 7). The legs 102 and 104 cG---~,.-sc two loops 106 und 108 .~l..~ely of the 2S Ib Berlcley Trilene Xl monofilament Each of the loops 106 und 108 has a ~ ... I...~ence of about 15.2 cm (6 0 inch) The legs 102 und 104 arc joined to the backsheet 24 at the second and third positions 113 and IIS laterally 3s spaced apart a distance 121 equal to about 30 mm The legs 102 and 104 ue joined to the core 26 at the f~rst position 111 which is located on thc lon~ Ainql centerline 29. The spring lOOB h~c substantially the same construction as the spring IOOA~ and is spaced Isn~ ly reuward of the spring lOOA a tistance 151 equal to about 70 nun o The spnng lOOC is spaced longt~lAin~lly rearward of the spring lOOB a d;c~n~e 171 equal to about 55 nun The spnng IOOC has a leg 102 co,-""isinY a WO 9S/171~9 PCr~S9~ 92 single loop 106 of the '5 Ib BerkJev Trilene XT monofilament. The sprin~ 100C has a leg 104 comprisin~ a single loop 108 of the 25 Ib Berkley Trilene .YT
monofilament. Each of the loops 106 and 108 has a circumference of about I 2 7 cm (5 0 inch). The legs 102 and 104 are joined to the backshee~ 24 at the second and third positions 113 and 115 laterally spaced apart a distance 161 equal to about I ~
o mm. and the legs 102 and 104 are joined to the core 26 at the first position 111.
which is located on the lon~n~ nql centerline 29.
The Z-direction calipers Z I and Z2, and the CGI I ~s~,onding Z-direction co,..p, cssive loading listed in Tables I -3 were measured using the followin~
procedure with an INSTRON Model 4502 tensile test ~ rnqn~f~t~ed by the Instron Fng;n<~ g Corp. of Canton, Mass. The sanitary napkins 20 to be tested should be con~ ;on~d for about 2 hours in a room at benveen 71 and 75 degree Fahrenheit and 48 to 52 percent relative humidity prior to testing.
The tensile test ~chin~ iS equipped with a 100 gram load cell. The sanitary napkin 20 is suppo,lcd. topsh~t 22 facing upwart. with the g. rment facing surface 25 of the b~-~ Ch~t 24 facing downward ant rea1ing on a hGI~G.ltal surface of a 6 inch diq~eter plate attachet to the ,l 4~;on ~ ~ jaw of the tensile test, --hine. A 1.0 inch ~ te~ hol~on~al cGIll~ sion foot is attached to the moving cloaal-cad of the tensile test rnachine to face the topslv~ 22 of the sanitay napkin 20. The cGIllpl~,salon foot is positionet along the lon~ n~l c~.a~,.L~c 29 of the sanitary napkin 20. The data in Table 1 (Front) is mea,suret with the cGIllprcsslon foot posi~ion~d appro~l,ately over the spring 100A, the data in Table 2 (Center~ is measured with the cG.,.~,nss,on foot position~d app,.,Au-lately over the spring 100B, and the data in Table 3 (Rear) is measured with the cG.."~rt~ sn foot positioned app, . ~,.ately over the spring 100C.
The initial Z-direction spacing between the staionary plate surface and the cG...pr~;on foot is greater than the ~ '~Pded Z~ ,on caliper of the of the sanita y napkin 20, and is at Iea,st 40 mm. The CG...t~ sion foot is then advanced toward the stationa y plate surface at a co~ .1 rate (~ s h ~ ~ d speed) of 10 inches per minute. The force measured by the load cell for a given spacing between the 35 col"preJa,on foot and the ~ ;on~-~ plate surface is l~.co,dcd on a strip chart l~co,d~,( at a chart speed of 20 inches per minute. The spacing between the colll~ a.on foot and the s _~;;r--y plate surface at a given load cG"~"onds to the Z-direction caliper of the sanitary napkin 20 at that load. When the spacing between the cG"Ipression foot and the s~tion~y plate surface has been reduced at least 25 mm from the spacing at a load of 2 grarns. or the load measured is greater than 100 WO9S/I~I~9 PCT~'S9~ S92 .0 grams. the direction of travel o~' the compression foot is reversed to retract from the stationary plate surface at a speed of 10 inches per minute.
The data in Tables 1-3 were obtained using the above procedure to measure the Z-direction caliper of five sanitary napkins 20 TABLE I
FRONT Z-D[RECTION CALIPER AND LOADING

Measurement Avera,l~ S D. Min. Max.
A. Caliper at 2 gm load: 26.1 mm 1.47 25.0 mm 28.5 mm B. Calipa at 2 gm unload: 22.3 mm 1.64 21,0 mm 25.0 mm C. Caliper reduced IS mm 11.1 mrn 1.27 10.0 mm 13.S mm from A
D. Force at Calipa C 17.9 gm 3.68 14.0 gm 22.0 ~n E. Calipa reduced 25 mrn 1.2 mm cl mm 3.5 mm from A
F. Force at Caliper E >100 gm >100 gm >100 gm G. Calipa at 90 gm load 3.3 mm 0.27 3.0 mm 3.5 mm 2S CENTER Z-D~ECTION CALIPER AND LOADING

Mcasu.~ Avera~ S.D. k~,. Max.
A. Calipa at 2 gm load: 30.2 mm 1.48 28.5 mm 32 mm B. Calipa at 2 ~n unload: 26.1 mm 1.56 24.S mm 28.5 mm C. Calipcr retuced 15 mffl 15.2 mm 1.48 13.5 mm 17.0 mrn &om A
D. ForccatCaliperC 35.1 gm 7.8 23.0gm 42.0gm E. Calipa rcduccd 25 mm 5.2 mm 1.48 3.5 mm 7.0 mm &omA
F. Forcc at Calipa E 38.6 gm 12.5 25.5 gm 48 gm G. Calipa at 90 gm load 3.4 mm 0.55 3.0 mm 4.0 mm WO95il71~9 PCT~'S9J/1~592 TABLE ~
REAR Z-DIRECTION CAL~PER A,~D LOADrNG

Measurement Avera~e S D Min. ~ax.
A Caliper at 2 gm load: 30.7 rnm 1.20 '9 5 m~m ~' mm o B. Caliperat 2gm unJoad: 24.5 mm 1 80 ".0 mm '6.5 mm C. Caliperreduced 15mm 15.7mm 1.20 14.5mm 170mm from A
D. Force a~ Caliper C 21.9 gm 2.72 18.0 gm 24.5 gm E. Caliper reducet 25 mm 5.7 mm 1.20 4.5 mm 7.0 mm from A
F. Force at Caliper E 33.8 gm 12.0 21 gm 49.5 gm G. Caliper at 90 gm load 3.5 mm 0.35 3.0 mm 4.0 mm Tables 1-3 list the average, al~dard teviation, minimum. and msYimllm of measulc."~ a A-G for five sanitary napkins 20 having the spnngs 100A-C shown in Figure 7. Measurement A is the Z-direction caliper of the sanitary napkin 20 af a load cell reading of 2 grams, as the co~ ;o~ foot is advancing toward the stationary plate surface. The caliiper at a load of 2 grams is r e~ -l ;c'ly the calipcr Z l of an unloaded sanitary napkin. Measurement B is the Z-d;re~,lion caliper of the2s sanitary napkins 20 at a load ccU reading of 2 grams, as the CG~.~p~ on foot is rnracting from the stationary plate surface, and shows that springs 100A~-C
subsla~ y restore the original, unloaded caliper of the sanitary napkin 20 upon removal of the Z-direction loading.
Mc~re.,.w~l C co.l~ o~lc to a second caliper Z2 which is 15 mm less than the caliper Z1 at 2 granu load. and ll-~ll~.l-C.II D is the Z-tu~,~1ion CGIll~ 'e force at the caliper C. Mc~.~ ...~..11 E col~..,~nds to a second caliper Z2 which is 25 mm less than the caliper Z I at 2 grams load, and measurement F is the Z-direction co..."resi~_ force measured at the caliper E. Measurement G is the Z-direction calipa of the sanitary napkin 20 when the Z-d~ion co...~.cs~.~e force is equal to 90 grarns. In Table 1, the force at caliper E ~ccdcd 100 grams becausc spring 100A was s~ ;sl~y flattened at that calip~.
Figure 10 is a graph slh,~ing the Z-d~.~.,~,on force measured by the tensile tcst ne u a fi)n~tion of the Z-d~,1ion calipa of a sanitary napkin 20 as shown in Figure 7, and u measured over the center spring 100B. The portion of graph labeled ~o 501 in Figure 10 shows the force-calipa rel~;o~-1h;l- as the co~ s~ion foot was advanced toward the stationary plate surface. The portion of the graph labeled 50~

WO 9S/171'~9 PCr/l,S9J/1 1~92 in Figure l0 shows the force-caliper relationship as the compression foot was retracted from the stationary plate surface. The portion of the ~raph labeled 501 illustrates that the Z-direction stiffness of the sanitary napkin having a spnn~ l00 can first decrease, and then increase. as the Z-direction caliper of the sanitarv napkin is reduced. In parlicular. the portion of the graph labeled 501 shows that the force first o increases to a local m~Yimurn as the caliper decreases. dc."eascs to a local minimum as the caliper is further reduced, and then inc.~a3cs as the spring 100B is fl~ttened The sanitary napkin lateral caliper and cGlle,~on~1;ng lateral load values listein Table 4 were obtai, cd using the procedure dcs_,il,od below, with reference to Figure 8, and with lefe.e.lce to a sanitary napkin 20 having the springs l00A-C
5 shown in Figure 7. The sanitary napkins 20 to be tested should be conditioned for about 2 hours in a room at between 71 and 75 degree Fahrenheit and 48 to 52 percent relative humitity prior to testing.
The sanitary napkin 20 is cGlll~Jle33~ lateraUy using a cor.~ ratc tensile/co..,pre~on test~ such as an EME model 599A tester available from EME, Inc. of Newbury, Ohio. The tester should use a load ceU with a sensitivity of at least 5 grarns and have a loat ran8e of at least 2000 grams. The load cdl should be calibrated so that force ll.c~l~e.l.cnti are accurate to within 2 percent for force measu~ nt~ above 100 grams. The testers measurement of position should be accurate to within at least 0.05 cm. An mic.ùco~p~t~r, such as an ~BM cG-~ ;ble 2s personal co~p~lt~r having an 80386 mielùyluce~s~r can be used to comrol the tester and acquire data during te~ing. The tester and mi: uC~ J 1t~r can be purchased as a system from EME, Inc.
A first circular plate 322 having a first surface 323 with a ~ te, of 40 mm is attsched to the moving cro~head of the tester. A second circular plate 324 having a secont surface 325 with a diameta of 40 mm is attached to the stationary load cell 326. cbmp. The plata 322 ant 324 are attached to the moving c~s ' ~ad and the load ceU such that the surfaces 323 and 325 are hG~O-~ l and parallel.
The surfaces 323 and 325 are initially spaced apart a did~ e of at ieast 37.5 mm. The sanitary napkin 20 is partially folded along the longitudinal axis 29 to fonT
3s a V-shape, with the body facing surface 25 of the topsheet co.n~w.ly shaped. The sanitary napkin 20 is folded the min~ .n amount necessary to pamit at least a portion of the topsh~ 22 and the absorbent core 26 to be positioned between the surfaces 323 and 325. Creasing of the top '~ 22 or the core 26 shoult be avoidedprior to activating the c,. ' ~ The b?~~e~ee~ 24 and the flaps 44 are plefe.ably'10 pulled away from the absorbent core 26 so as not to be p~s;~;oncd between the surfaces 323 and 325. The lateral ends 30 of the sanitaly napkin 20 can be held WO9S/17119 PCT~S9~11JS92 while the sanitary napkin 20 is rested on the surface 325~ to prevent the sprin~s 100A-C from causin~ the sanitary napkin to unfold and fall from between the surfaces 3'3 and 325 The tester is then started to advance the surface 323 toward ~he surface 325.
As the surface 323 advances toward the surface 325 the support at the lateral o ends 30 can be released. The. surface 323 is advanced toward the surface 325 at a COhSI~t rate of .158 clTJscc. As the surface 323 is advanced toward the surface 325, thc topsl,c~.l 22 and the core 26 should be foldet such that two layers of each of the topshc~l 22 and the core 26 are pGa,l,oncd bet veen the surfaces 323 and 325. as shown in Figure 8, with at least a portion of one of the springs 100 sandwiched IS between two layers of the corc and two layers of the tOpallc~,l. Force and values are - ~lei at a rate of at least 40 data points per second. The lateral caliper of the sanitary napkin (the tistance between the surfaces 323 and 325) iS l~,CGl~ at lateral force levels of 50, 100, 300, 1000, ant 2000 grams. The lateral caliper ant cG"~;~,on~ g lateral force measurt.,-~,~ls are mate for at leas~t three sanitary napkins. The average lateral calip~ reating for three sanitary napkins is reportet at each of the lateral force levels 50, 100, 300, 1000, ant 2000 grams in Table 4.

LATERAL CALIPER AND LOADING

M~ ament Aver~e S D.
Calipa at 50 grn 9.3 mm 0.0 Calipa at 100 grn 6.1 mm 0.0 Caliperat 300gm 3.8mm 0.01 Caliper at 1000 gm 2.6 mm 0.01 Caliper at 2000 gm 1.9 m n 0.01 While particular embodimants of the prescnt ~ ion have been illustrated 35 ant dc~, ibcd, the scopc of the present in~ ion is tefined by the arp~ ndCd claims.

Claims (29)

1. A disposable absorbent article having a longitudinal centerline and longitudinal ends joining first and second lateral ends, the absorbent article comprising:
a liquid pervious topsheet having a body facing surface;
a liquid impervious backsheet having a garment facing surface, the backsheet joined to the topsheet;
an absorbent core disposed intermediate the topsheet and the backsheet; and a non-absorbent spring disposed intermediate the absorbent core and the backsheet for providing Z-direction elastic displacement of a portion of the topsheet relative to the backsheet.

2. The disposable absorbent article of Claim 1 wherein the spring convexly shapes a portion of the body facing surface of the topsheet along the longitudinal centerline of the absorbent article.

3. The disposable absorbent article of Claim 2 wherein the spring provides a Z-direction elastic displacement of a portion of the body facing surface of the topsheet relative to the garment facing surface of the backsheet of at least 15 millimeters.

4. The disposable absorbent article of Claim 1 wherein the absorbent core and the topsheet are joined to be displaced by the spring as a unit, and wherein thetopsheet is joined to the backsheet to provide independent Z-direction movement of the topsheet and absorbent core relative to the backsheet.

5. The disposable absorbent article of Claim 4 wherein the topsheet is joined tothe backsheet to provide longitudinal decoupling of motion of the topsheet and absorbent core relative to the backsheet.

6. The disposable absorbent of Claim 4 further comprising at least one longitudinally extending pleat joining the topsheet to the backsheet for controlling separation of the topsheet from the backsheet.

7. The disposable absorbent article of Claim 1 wherein the topsheet and the absorbent core have combined Taber bending stiffness in each of the longitudinal and lateral directions of less than 2 gram-centimeters.

8. The disposable absorbent article of Claim 1 wherein the absorbent core is segmented to provide at least two independently Z-direction displaceable core segments, and the absorbent article having at least one spring associated with each of the two core segments.

9. The disposable absorbent article of Claim 1 having a first Z-direction caliper at a Z-direction compressive load of 2 grams and a second Z-direction caliper at a Z-direction compressive load of less than 100 grams, wherein the second Z-direction caliper is at least 15 millimeters less than the first Z-direction caliper.

10. The disposable absorbent article of Claim 9 having a second Z-direction caliper at a Z-direction compressive load of less than 50 grams; wherein the second Z-direction caliper is at least 15 millimeters less than the first Z-direction caliper.

11. The disposable absorbent article of Claim 10 having a second Z-direction caliper at a Z-direction compressive load of less than 25 grams; wherein the second Z-direction caliper is at least 15 millimeters less than the first Z-direction caliper.

12. The disposable absorbent article of Claim 1 having a first Z-direction caliper at a Z-direction compressive load of 2 grams and a second Z-direction caliper at a Z-direction compressive load of less than 100 grams, wherein the second Z-direction caliper is at least 25 millimeters less than the first Z-direction caliper.

13. The disposable absorbent article of Claim 12 having a second Z-direction caliper at a Z-direction compressive load of less than 50 grams; wherein the second Z-direction caliper is at least 25 millimeters less than the first Z-direction caliper.

14. The disposable absorbent article of Claim 8 having a Z-direction caliper of less than 10 millimeters at a Z-direction compressive load of 90 grams.

15. The disposable absorbent article of Claim 9 having a Z-direction caliper of less than 5 millimeters at a Z-direction compressive load of 90 grams.

16. The disposable absorbent article of Claim 9 having a lateral caliper of lessthan 10 millimeters at a lateral compressive load of 100 grams.

17. The disposable absorbent article of Claim 9 having a lateral caliper of lessthan 5 millimeters at a lateral compressive load of 300 grams.

18. The disposable absorbent article of Claim 9 having a lateral caliper of lessthan 3 millimeters at a lateral compressive load of 1000 grams.

19. The disposable absorbent article of Claim 1 having a Z-direction stiffness which first decreases, and then increases, as the Z-direction caliper of the disposable article is reduced.

20. A disposable absorbent article having a longitudinal centerline and longitudinal ends joining first and second lateral ends, the absorbent article comprising:
a liquid pervious topsheet having a body facing surface;
a liquid impervious backsheet having a garment facing surface, the backsheet joined to the topsheet;
an absorbent core disposed intermediate the topsheet and the backsheet; and a filament spring disposed intermediate the topsheet and the backsheet for providing Z-direction elastic displacement of a portion of the topsheet relative to the backsheet, and for convexly shaping a portion of the body facing surface of the topsheet along the longitudinal centerline of the absorbent article.

21. The disposable absorbent article of Claim 20 wherein the filament spring is disposed between the absorbent core and the backsheet.

22. The disposable absorbent article of Claim 20 wherein the filament spring comprises non-parallel first and second legs, each leg forming an included angle of less than 90 degrees with a line parallel to the Z-direction when the disposable absorbent article is in an extended position.

23. The disposable absorbent article of Claim 22 wherein each leg is joined to the absorbent core at a first position along the longitudinal centerline of the disposable absorbent article.

24. The disposable absorbent article of Claim 23 wherein each leg of the filament spring is joined to the backsheet at laterally spaced apart second and third positions symmetrically positioned with respect to the longitudinal centerline of the disposable absorbent article.

25. The disposable absorbent article of Claim 22 wherein the filament spring comprises first and second separate legs spaced apart in the lateral direction, each leg joined to the core at separate. laterally spaced apart locations, and wherein the legs are joined to the backsheet at laterally spaced apart positions symmetrically positioned with respect to the longitudinal centerline of the disposable absorbent article.

26. The disposable absorbent article of Claim 22 wherein each leg comprises an arcuate segment.

27. The disposable absorbent article of Claim 20 wherein the filament spring comprises:
a first closed loop joined to the absorbent core at a first position generally aligned with the longitudinal centerline of the disposable absorbent article and joined to the backsheet at a second position laterally spaced from the longitudinal centerline;
and a second closed loop joined to the absorbent core at a first position generally aligned with the longitudinal centerline of the disposable absorbent article and joined to the backsheet at a third position laterally spaced from the longitudinal centerline;
wherein the first and second closed loops form an inverted V shape as viewed along the longitudinal centerline of the disposable absorbent article.

28 28. A disposable absorbent article having a longitudinal centerline and longitudinal ends joining first and second lateral ends, the absorbent article comprising:
a liquid pervious topsheet having a body facing surface;
a liquid impervious backsheet having a garment facing surface, the backsheet joined to the topsheet;
an absorbent core disposed intermediate the topsheet and the backsheet; and a spring disposed intermediate the absorbent core and the backsheet for providing Z-direction elastic displacement of a portion of the topsheet relative to the backsheet, the spring having a wet caliper reduction of no more than about 8 percent.

29. A disposable absorbent article having a longitudinal centerline and longitudinal ends joining first and second lateral ends, the absorbent article comprising:
a liquid pervious topsheet having a body facing surface;
a liquid impervious backsheet having a garment facing surface, the backsheet joined to the topsheet;
an absorbent core disposed intermediate the topsheet and the backsheet; and a spring disposed intermediate the absorbent core and the backsheet for providing Z-direction elastic displacement of a portion of the topsheet relative to the backsheet, the spring having a wet caliper reduction which is no more than about 20 percent greater than the dry caliper reduction of the spring.