CA2257278A1 - Breathable stain resistant undergarment for use with an absorbent article - Google Patents

Abstract

An undergarment (20) for use with an absorbent article is described. The undergarment comprises a shell portion (30), a crotch portion (40) and elasticized leg openings (34) defined by the shell portion (30) and the crotch portion (40). The shell portion is breathable and preferably, liquid resistant. The crotch portion (40), which is elastically extensible in at least one of the longitudinal and the transverse directions, comprises an absorbent body layer and a liquid resistant barrier layer, and is preferably, breathable. The elasticized leg openings (34) cooperate with the elastically extensible crotch portion to provide a biasing force for an absorbent article against a wearer's body. A system for control of bodily fluids comprising an undergarment and an absorbent article is also described.

Description

W O97/46198 PCT~US97/09568 I~REAT~ABLE STAIN RESISTANT UNDERGARMENT
FOR USE WIT~I AN ABSORBENT ARTICLE

(~ROSS-REFERENCF TO RELATED APPLICATION
This disclosure incorporates and has the priority of U.S. Provisional Patent Application Serial No. 60/01~102, filed on June 3, 1996 in the names of Lee, et al.

FIELD OF THE INVENTION
The present invention relates to undergarments, particularly to underga;ments that can be used in conjunction with an absorbent article, and more particularly to unde~,allllc;ll~s a user can wear with a c~l~....ç.-i,.l device during her menstrual period.

BACKGR'3UND OF THE INV~NTION
As is known, disposable r.,.t~m~ni~l devices are co~ lle~cially available in a wide variety of configurations for the specific purpose of absorbing and ret,.ining menstrual fluids and other vaginal disch~,es. U~ unalely, such c~l~"~F~ devices may leak menses along their periphery due to poor fit or improper pl~r,~m~nt Such leakagefrequently results in soiling of a ~al el'~ undergarments, clothing and bedding.
To provide additional protection against leakage, it is known to use a washable and reusable ~,allllGII~, such as a menstrual short or panty, in combination with a disposable e~t~ F.l~ pad. For ~ A2.lllple, U.S. Patent 3,489,149, issued to Larson on January 13, 1970, discloses a washable menstrual panty having a small pocket in the crotch area for l~ -g a disposable c~r--.~ pad. Since the menses must initially flow through a layer of material forming the pocket to reach the catamenial pad,removal of the soiled c~ e~ l pad can be ~ t~tefill~ difflcult and m~ y. While a new pad can be inserted into the pocket, the garment is already soiled and would typically be changed. Also, the pocket may not accommodate the varied sizes of c~l~...el~i~l devices currently on the market. Further, the layer of moisture resistant material described therein fails to provide ventilation or breathability in the crotch region with a res lltin~ potential for wearer discomfort when such a panty is worn.

W O 97146198 PCT~US97/09568 The art has also attempted to address leakage from a catamenial device by providing absorbent material in a region surrounding the device and means for positioning the catAm~ni~1 device. For example, U.S. Patent 4,560,381, issued toSouthwell on December 24, 1985, describes a mesh-like outer panty shell with a thick inner layer of absorbent material in the lower crotch area of the panty. The inner layer of absorbent material inrl~lde,c a dèples:jiOn for receiving and positioning a c~t~mRniAl pad. An alternative embodiment incl~ldçs a barrier film between the absorbent material and the panty shell. However, if the barrier film is present, the crotch portion will not be breathable (with resl-ltin~ disco,l,rolL) and if the barrier film is absent, there is a risk of leAk~e In U.S. Patent 4,813,950, issued to Branch on March 21, 1989, a washable menstrual panty is disclosed as having an outer lining of sp~nd~x~ soft tricot, etc.
which provides a "skin tight or almost skin tight" fit and an inner lining of a microporous plastic film to prevent p~ccAge of menses thc~,Ll,lo~lgh while allowing pACc~ge of gasses. Similarly, eYisting Japanese-style menstrual shorts act like a girdle or a very tight fitting panty which holds a c~ ,iAl device in the wearer's p~ nrlAI
region. Positioning of the catamenial device for such undelgalll.cnts is achieved by the tightnf~ss of the ll~en:.Llual short which, in turn, may cause discornfort to the wearer. Further, any leakage of menses along the periphery of the cAtAm~ni~l device could easily pass to outer garments because there is no provision for absorbing such leakage and wearer movement can create gapping in leg elastics.
A menstrual short panty having an elastic piece fixed to the front and rear of the crotch region in an elc-ng~ted state is desclil,ed in U.S. Patent 3,608,551, issued to Seijo on Se~le.~;er 28, 1971. The elastic piece is said to keep a sanitary napkin raised and in contact with a wearer's body irrespective of her physical movements.
The elastic piece is joined to the leg openings by an open mesh neL~vo,k and thecrotch region underlies the network. While such a device may improve body contact, the risk of wearer disco",ru, I is relatively high because the narrow elastic piece which provides all of the lifting would tend to force the sani~l,y napkin it supports into the axis of the vulvular cleft or the gluteal groove. Further, the Seijo device makes no provision to acco.. ~odate any liquids that may leak around the periphery of the sanitary napkin.
Di~posable menstrual panties are also known. For example PCT Application WO 95/06451 published in the name of Kimberly-Clark Corporation on March 9, 1995 des~,l il,es a disposable menstrual panty said to provide backup leakage CA 022~7278 1998-12-02 W 097146198 PCTrUS97/09S68 plùte~;lion by way of an absorbent/barrier composite positioned in the crotch area of the panty. The menstrual panty described therein is also provided with circull~elelllially oriented elastics said to allow the panty to conîo~ln to various body types and builds. However, because they only encircle a wearer's waist and hip areas, such elastics provide no "z direction" (i.e. upward) biasing force to help ...~ a c~t~m~ni~l device in contact with a wearer's p~d~n~ region. As a result, there is a risk of leakage around the c~ ...~.-;~l device and a res-llt~nt risk of soiled outer garments or bedding.
It is therefo~e an object of the present invention to provide an improved menstrual unde-ga----enl for use with a catamenial device which provides a biasing force to help insure close contact between the c~t~meni~l device and a wearer's p~ nrl~i region throughout the full range of wearer motions. It is a further obiect of the invention to provide a menstrual unde-g~ with a dual protection system wherein the crotch portion of the undel~;~ulll~,.ll is liquid absorbent yet resists transport of liquids Ih~r~Lllluugh and the shell portion of the undel~llllenl resists st~ining by bodily fluids such as menses. It is still a further object of the present invention tû provide a menstrual undergarment that is breathable throughout both the body and the crotch portions.
These and various other objectives of the present invention will be more readilyappalelll when considered in reference to the following description and when taken in cQrj~lnction with the accol-~lyi~lg drawings.

S1~1MARY OF THE INVENTIC)N
The present invention is directed to an undel~,allllell~ to be worn in conjunction with an absoll,elll article. While the present invention is described in terms of an und~,~ a,.n~,ll to be worn with a caLa,..enial device by women during their norrnally occurring "-en~ al period, the invention is not limited to only such uses. In particular, the present invention is also suitable for use with absorbent articles ~esi~ned to control other bodily fluids (e. g. adult incontinence devices, diaper inserts, and the like~. In a p,~rt;"ed embodiment, the present invention is a legless, tubular knit unde,~a""cnl which con~plise,s a breathable, liquid resistant shell portion having an el~tiri~rd waist opening, an absorbent, preferably breathable, el~cti-~lly e~-~;ble crotch portion, which also acts as a barrier to leakage, and a pair of elasticized leg opel~in~ ,.

CA 022~7278 1998-12-02 W O 97146198 PCT~US97/09568 The shell portion is liquid resistant because it is treated to be subst~nti~lly hydrophobic. As a result bodily fluids, such as m~n.c~?c, are less likely to wet the shell portion than if the shell portion were untreated. Such hydrophobicity reduces the risk of st~ining Further, pressure is required to force such bodily fluids through the structure of the shell portion recl~lring the risk of leakage with resnlting soiling of outer ga.mc..~S or bedding. Pler~lably, the fibers Col~ g the shell portion are treated with a hyd~ ophobic, surface active material, such as a fluorocarbon, toprovide the requisite hydrophobicity.
The crotch portion has two layers: a liquid resistant barrier layer and an absoll cnL body layer. Liquid resistance is provided either by Llei9lm~.l with ahydrophobic, surface active material or by provision of a fluid resistant film l~min~te Absorbency can be provided either by integral means, such as knitting absorbent materials into the crotch portion of the undergarment and subsequently treating the ga..llenl surface thereof to become liquid r~ or by disposing an absorbent component onto a g~lllenl layer that is treated to be liquid le~ l The crotch portion is also pl~relably ~lqctic~1ly e~ onQ;hle, more preferably the crotch portion is el~tic~lly extensible in both the longit~l~in~l and transverse directions. This elastic ~;~k,.l~ilJIlily provides a biasing force in the "z-direction" which helps m~int~in an absorbent article in contact with a wearer's body. For example, when used with ac~m~ni~l device, such a biasing force helps m~int~in the c~t~me~i~l device in contact with the ~,alel's p~d~n~i~l region throughout the full range of wearer motions.
Both the shell portion and the crotch portion are also ple~rel~bly breathable for improved wearer colllrul L

BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a front view of a pl t;rel I ed embodiment of the menstrual undel~ ~lllcll~ ofthe present invention;
Figure 2 is a rear view of the menstrual undel~ shown in Figure l;
Figure 3 is a plan view of the menstrual undergarment shown in Figure 1 that has been opened at the side seams, the elastic components being pulled flat;

CA 022~7278 1998-12-02 W O97/46198 PCT~US97/09568 Figure 4 shows, in a composite fashion and on a m~gnified scale, the loop structure of the p.~.led tubular knit fabric of the menstrual undergarrnent of the present invention;
Figure S is a cross sectional view of the menstrual undergarment of the present invention along line 4-4 of Figure 3;
Figure 6 is a cross sectional view, similar to Figure 5, of an alternative embodiment ofthe menstrual unde.~,a----~,l.l ofthe present invention.

DETAILED DESCRIPTION OF THE INVENTION
As used herein, the term "c~t~mPni~l device" refers to an absorbent article which is worn by females ~ qcçnt to the plldPn-l~l region for absorbing and cont~inin~ bodily fluids, such as menstrual fluids and other vaginal discharges. Also as used herein, the term "disposable" refers to structures which are not intçndçd to be laundered or otherwise restored or reused after use (i.e., they are intçnfled to be discarded after a single use, and, preferably, to be recycled, composted or otherwise disposed of in an environmPnt~lly compatible manner). As used herein, the term "pud~n-l~l" refers to the externally visible female gPnit~ and is limited to the labia maiora, the labia minora, the clitoris and the vaginal vestibule. ~n addition, the term "perineum" refers to the external region of the female's body between the anus and the pudçnd~l region while the term "gluteal groove" refers to the crevice between the buttocks (gluteus maximi) e~ctpn~ling upwardly from the perineum. As used herein, the terms "fluid", "liquid" and the like are intPnded to be in~ hangeable and refer to materials that are in a liquid state when they are at a te...p~ re of about 100~F. It should be understood, however, that the present invention is also applicable for use not only with c~ l devices such as sanitary napkins, panty liners, and the like (inrllltlin~ interlabial devices) but also other absorbent articles such as incontinPnce devices, diapèr inserts, and the like.
General Description of the Unde~ gdl III~
While, as noted above, the present invention is suitable for use with a wide variety of abso-l,en~ articles, it will be described in terms of a menstrual undelga----en~ 20 which may be used in conjunction with a c~t~mPni~l device 80.
Figures 1 and 2 show front and rear views of the menstrual undergarment 20 of the present invention. As is shown in Figures 1 and 2, the menstrual undergarrnent 20 of CA 022~7278 1998-12-02 W O97/46198 PCTnUS97/09568 the present invention comprises a shell portion 30 and a crotch portion 40. The menstrual undergarment 20 has a front region 52, leg openings 34, a rear region 54, and a waist opening 33 having an elastic w~i~tb~nd 32 for ...~ g the menstrual undergarment 20 on a wearer. The shell portion 30 and the crotch portion 40 cooperate to form the leg opc.~ g 34 which are also provided with leg elastics 35 to further provide a collro,l. i.lg fit and to seal the leg opening 34 against leakage of menses and other bodily fluids. Side seams 38A 38B join the front region 52 to the rear region 54. The menstrual undergarment 20 can be any style, for example "bikini", "tanga", "French cut", American style, or the like.
Figure 3 shows the menstrual unde~galn~e-lL of the present invention in a full flat out position wherein each of the side seams 38A, 38B has been opened and elastic colllponents have been pulled ~dat. Figure 3 can also be considered to be a plan view of a blank for the menstrual undergarment 20. As can be seen from Figure 3, the menstrual undergarment 20 has a lon~hurlin~l center1ine L and a transverse cenlellille T.
The menstrual undergarment 20 can coll")lise woven, nonwoven or knit fabrics.
P~ ably the menstrual und~ nL 20 co,..p.ises a knit fabric. A particularly l)-t;~-led knittir~ means involves f;rst knitting a se~mle~c tubular blank applo,.;...~ely half the final width of the menstrual undt,l~allnellL 20. The tubular blank may be knit to have an hour glass shape so as to provide for the leg openings 34 in the l~ ed Ille~ lual unde.~,allllc.,L 20 or, alternatively, portions of the opened tube may be cut away to provide for such leg openings 34. This pr~relled knitting means is described in greater detail in U.S. Patent 3,985,004, issued to Johnson, et al.
on October 12, 1976, the disclosure of which is incorporated herein by reference.
Figure 4 shows, in a composite fashion and on a magnified scale, the loop structure of the p-~,fe.led tubular knit fabric of the menstrual undergarment 20 of the present invention. The knit pattern of the courses shown as 60 in Figure 4 corresponds to the knit pattem used for the shell portion 30. The courses shown as 64 correspond to the knit pattern used for the central region 45 of the crotch portion 40, and the courses shown as 62 co"espond to a transitional pattem used for the rem~inrler of the crotch 40. The floats, shown as F, Fl, and F2, help provide the crotch portion 40 with an attractive ribbed ~ppealànce~ These ribs also help direct the flow of any bodily fluids that may be deposited on the crotch portion 40 in the longitll-iin~ direction.
The blank for the menstrual undergarrnent 20 is first knit in a tubular form. The tubular blank is then slit waiewise and opened to forrn a flat blank for the menstrual _ CA 022~7278 1998-12-02 W O97/46198 PCTrUS97tO9568 undergarment 20 having a shape similar to the plan view of the menstrual undergarment 20 that is shown in Figure 3. As is further shown in Figure 3, the blank for the menstrual undergarment has a front end edge 3 lF, a rear end edge 31R, front - side edges 36A, 36B, and rear side edges 37A, 3733. The elastic waistband 32 may be formed by providing an elastic member, such as a LYCRA material, ~ cçnt each distal end of a panty blank, C-folding each distal end of the blank about itself to form end edges 3 lF and 31R, and se~ming the distal ends to the shell portion 30 to form the elastic w~i~tb~n-l 32. Pl~relably~ the elastic waistband 32 comprises a turned welt.
The leg elastics 35 (described below) are joined to that portion of the side edges 36, 37 which will ~u--ound the leg openings 34 (i. e. form the periphery thereof). The blank for the menstrual undelga..l.c.,l 20 is then folded about the transverse centerline T and opposing portions of the side edges 36, 37 that lie between the leg opening 34 and the end edge 31 are joined to form side seams 38A, 38B completingthe assembly of menstrual undergarment 20 (That is, the portion of side edge 36Athat lies between the end of the leg elastic 35 that lies in the front region 52 and the end edge 3 IF is joined to the portion of side edge 37A that lies bet~,veen the end of the leg elastic that lies in the rear region 54 and the end edge 31R to form seam 38A.
Side edge 36B is joined to side edge 37B in a similar manner to forrn seam 38B).
Alternatively, portions of the tubular knit blank can be cut out to provide the leg openings 34. For c,~a nple, a tubular blank can be fl~tten~-~, such that, the interior faces thereof contact each other and a pair longit~ in~lly oriented side edges are formed. Leg opening precursors can then be formed by cutting m~tc.hing portions having a semi-circular, serni-elliptical, or other desired shape from transversely opposite side edges at regular intervals along the fl~tt~ned blank. Undergarmentblanks are then formed by transversely cutting the fl~tt~ned tubular blank in a pred~,t~ ed repeat pattern wherein a first transverse cut is made across the material that was not removed when the leg opening precursors were formed to create a crotch portion precursor and a second transverse cut is made across the full width of the fl~tt~ned tubular blank forrning the waist opening 33. The two endsformed by the first transverse cut are joined by a single transverse seam and, depending on the particular structure chosen for the crotch portion 40 (discussed ~ below), a body layer 46 can be disposed on and joined to the inner surface of the panty blank or a barrier layer 48 can be disposed on and joined to the outer surface of the panty blank to co.--pl~,Le the crotch portion 40. The menstrual undergarment 20 is then fin~hed by disposing leg elastics 35 about the periphery of each leg opening 34 -W O97146198 PCTfUS97/09568 and joining the leg elastics 35 thereto and disposing the elastic waistband 32 about the periphery ofthe waist opening 33 and~oining the elastic waistband 32 thereto.
The Shell Portion As can be seen in Figures 1 and 2, the shell portion 30 is that portion of the menstrual unde-~a,.l.enL 20 that is adapted to encircle a wearer's waist and hips. The shell portion 30 is provided with a waist opening 33 allowing entry into the menstrual und~l~,~l"enl 20. The waist opelul~g is provided with an elastic w~i~tb~nd 32 allowing the menstrual unde~g~ l.lelll 20 to fit a variety of sizes. As can be also seen in Figures 1 and 2, the shell portion also co-operates with the crotch portion 40 to define the leg openings 34 ~iec~ ed in detail below).
In the ~,rc;rG---ed embodiment of the present invention sho~,vn in Figures 1 to 3, the shell portion 30 is .o1~ctic~11y extensible. Such elastic extensibility enables the menstrual unde-~ --cllL 20 of the present invention to ft a variety of bodily shapes and sizes and provides good conr~l..uly to a weal~ body. An el~tic~lly extensible shell portion 30 further co-operates with the crotch portion 40 to provide a "z-direction" biasing force to the crotch portion 40 throughout the full range of wearer movement. Such a biasing force helps ..~ ;.. a calan~enial device 80 worn with the .~e..~L~ual ulld~ t 20 in close bodily contact, particularly with a wearer'spllden~l region. More preferably, such a biasing force directs the c~ l device 80 against the distal edges of a wearer's labia majora. Plcre.~bly, the shell portion 30 is constructed so as to provide a stretch modulus of b~Lween about 130 grams/inch (5 l grams/cm) and about 160 grams/inch (63 grams/cm). More preferably the stretch modulus is b~ en about 140 grarns/inch (55 grams/cm) and about 150 grams/inch (59 grams/cm). A suitable method for measuring stretch modulus is described in the TEST METHODS section below.
In a particularly plere-.ed embodiment of the present invention7 the shell portion 30 is also liquid ~ That is, the shell portion 30 resists the transport of aqueous liquids th~,.eLIuuugh and, preferably, the flow of aqueous liquids thereon.
More p-efe.~bly, the shell portion 30 is liquid ~esis~ L because the shell portion 30 is hydrophobic to resist the flow of liquids thereon. As used herein, a surface is "hydrophobic" if it has a critical surface tension of less than about 35 dynes per c~ er or a surface can be made "hydrophobic" by treating that surface with a material having a critical surface tension of less than about 35 dynes per centimeter and a "hydrophilic" surface is one wherein water forms a contact angle of less than CA 022~7278 1998-12-02 W O97/46198 PCT~US97109568 about 89 degrees thereon. By having a hydrophobic surface, the shell portion 30 resists the transfer of any bodily fluids from the crotch portion 40, which is int~n-1ed to absorb and contain any leakage around the periphery of a catamenial device 80that may be disposed thereon (~ c~eeed below), to the shell portion 30.
In a particularly pler~..ed embodiment, the shell portion 30 is breathable so the menstrual undelg~lll-enl 20 is more conlro-lable to wear. As used herein, a material is "breathable" if the air permeability of the material is greater than about 25 cubic feet per minute per square meter (0.7 cubic meters per minute per square meter) when measured as described in the TEST METHODS section below. Preferably, the air pe----eal~ility of the shell portion 30 is greater than about 220 cubic feet per minute per square meter (6.5 cubic meters per minute per square meter). More preferably, the air pel-.-eability of the shell portion 30 is greater than about 300 cubic feet per minute per square meter (8.5 cubic meters per minute per square meter).
The shell portion 30 can comprise any woven or nonwoven fabric having suitable feel, appearance, and surface properties. Preferably, the shell portion 30 comprises a woven or knit fabric. Fibers or yarns suitable for fabrication into the shell portion 30 include: polyolefin fibers, such as polyethylene or polypropylene fibers;
nylon fibers; elastomeric fibers, such as ~YCRA, and fibers of natural origin, such as cotton. Particularly pl ~re~ ~ ed for the shell portion 30 of the menstrual undel y,a~ en~
20 is stretch nylon available from DuPont of Wilmin~ton, DE. Such yarns are more~Llelchable than the cotton yarns frequently used for women's unde-ga----G--~
Preferably, such fibers are knit using means known to the art. More preferably, theyarns are wholly plain knit, as shown at 60 in Figure 4, to form the shell portion 30.
To provide liquid re~iet~nce to the shell portion 30 for the particularly ~ulerellèd embodiment ~ clle~ed above, the shell portion 30 can be treated using materials known to the art for providing such liquid r~eiet~nce. Such materials include fatty acid or fatty alcohol derivatives, silicones, polyurethanes and fluorocarbons.
Particularly p. èrélled are fluorocarbon materials because of the low surface energy of fluorocarbon ~.ulr~ces~ For example, an all fluorocarbon surface has a critical surface tension of about 20 dynes per centimeter or less. Suitable fluorocarbon materials include those available from DuPont Specialty Chemicals, Wilmin~on, DE as ZONYL~) and from 3M, Specialty Chemicals Division, St. Paul, MN. Particularly plerellt;d are ZONYL(~ 6991 from DuPont and FC-280 from 3M.

CA 022~7278 1998-12-02 W O97/46198 PCT~US97/09568 Treating the shell portion 30 for liquid resistance as described above causes the shell portion 30 to resist the transport of liquids therethrough because such tre~tm~nt lowers the surface energy of the shell portion 30 such that liquid transport is inhibited. See, for e,.a,l"~le, Adamson, A. W., Physical Chemistry of Surfaces 3rd Edition, John Wiley & Sons, New York, at 462 for a discussion of such behavior. As discussed therein, fabrics are made water repellent (i. e. Ii~uid re~ ,lalll) by providing them with a surface having a contact angle with water of greater than 90 degrees.
Materials providing a surface having a contact angle with water that is greater than 90 degrees include fluorocarbon materials, silicone materials, and waxy coatings.
To treat the shell portion 30 for li~uid resict~nfe the following steps are suitable 1) knit a blank as described above, 2) wash the blank to remove fiber finishes and the like, 3) treat the washed blank with the fluorocarbon material as the last step of the wash cycle according to the material supplier's instructions, 4) allow the blank to dry, 5) slit the blank, and 6) convert the slit blank into a fini.chçd panty as described above. This method treats the entire panty blank with the fluorocarbonmaterial. Treating the entire blank to become liquid resistant means that absorbent material must be provided to the crotch portion 40 to insure the crotch portion 40 has sufflcient absorbency (tlicc~.c~ed in detail below). Alternatively, the fluorocarbon material can be selectively applied to only the shell portion 30 using means such as p?~ in~ spraying or other means familiar to the art to apply a solution (or emulsion or suspension) of the fluorocarbon material onto the shell portion 30 only and allowing the fluorocarbon material to dry thereon.
The Grotch Portion As can be seen in Figures I to 3, the crotch portion 40 is that portion of the menstn~al unde.ga~ Gn~ 20 that is disposed between a wearer's legs and extends toward the elastic w~ictb~nd 32 at least to the vicinity of and preferably above a wearer's monS pubis in the front region 52 when the menstrual undergarment 20 isworn and at least in the vicinity of and p-Grt;l~bly above the tG.-llination of a wearer's gluteal groove (i e the groove formed by the intersection of a wearer's gluteus maximi muscles) in the rear region 54. The crotch portion 40 provides support for a ç~ts~.n~ l device ~0 when the menstrual undergarment 20 is worn. The crotch portion 40 has a periphery 41, a front apex 43F, and a rear apex 43R. As used herein, the term "apex" is intenrled to refer to that position on the crotch portion 40 that is most distant from the intersection of the longituriin~l centerline L and the transverse centerline T.

CA 022~7278 1998-12-02 W O 97/46198 PCTrUS97/09568 The crotch portion 40 is further provided with a central region 45 that is pl~f~,~bly knit with alternating courses having two yarns as shown at 64 in Figure 4.
The r~.n~infler of the crotch portion 40 is ~n c;r~ bly knit as is shown at 62 in Figure 4 which provides a transition between the knit pattern used for the shell portion 30 and the knit pattern used for the central region 45 of the crotch portion 40.
Plef ,~bty, at least a portion ofthe yarns used to knit the crotch portion 40 comprise cotton yarns. More plerGI~bly, those courses having yarns that are floated, as at F, F 1, and F2 in Figure 4, comprise cotton yarns.
As can be seen most clearly in Figure 3, the crotch portion preferably has a generally oval shape. Although other geometrical shapes, such as rect~n~ll~r~ are also suitable. More preferably such oval shape is symmetrical about the longit~1fiin~l centerline L and aYy.l.mGllic about the transverse centerline T. This oval shape is sufficiently large to extend longitu-1in~11y beyond a cfl~ device 80 that is disposed thereon such that any leakage past the ends of such a c~t~m~niAl device 80 can be absorbed by the crotch portion 40. Specifically, the asym}netric shape shown in Figure 3 is plGfellGd in order to insure that absoll el,L material (i. e. the body layer 46, 146 fliccllcsed below) is available for absorbing any leakage that may occur along a wGalGI'~ gluteal groove. Such absoll,e,lcy properties are discussed in greater detail below. Preferably, the ratio of the rlict~nce between the transverse centerline T and front apex 43F to the fliet~nne between the transverse centerline T and front end edge 31F is at least about 0.4:1. More IJlerGla~ly, the front ratio is at least about 0.5:1.
Similarly, the ratio of the f1ic~n~e between the transverse centerline T and rear apex 43R to the ~lict~nce between the transverse centerline T and rear end edge 3 lR is at least about 0.6:1. More preferably the rear ratio is at least about 0.67:1. Also, the overall longit~lf1in~l length of the crotch portion 40 is pl~r~.~ly greater than about 50~/0 of the longit~lflin~l fl;YI j~n~e between the front end edge 31F and the rear end edge 31R when the menstrual undel~,al..,~,.-l 20 is in the flat out configuration shown in Figure 3.
The crotch portion 40 is soft and flexible so that it is not a source of disco.,lro, L
for a wearer. PIGÇG.ably, the crotch portion 40 is ~l~etic~lly ~tensihle with a vector component in at least the transverse direction. More prerGI ably, the crotch portion 40 is el~stic~lly c ,.~en,Yible with vector con-pollents in both the longit~ in~l and transverse directions. Such elastic extensibility helps to provide a ç~tArn~ni~l device 80 disposed on the crotch portion 40 with a uniforrn upward biasing force against the distal edges of the labia majora creating an improved seal therewith and red~1cing the potential for leakage around the periphery of the c~t~m~ni~l device 80. Preferably, W O 97/46198 PCT~US97/09568 the stretch modulus in both the longitu-1in~1 and the transverse directions is equal to or less than the modulus of a wearer's skin so that the crotch portion will readily conform to the full range of wearer movements helping to insure that the menstrual undergarrnent 20 is coll,rolLable to wear. That is, the stretch modulus of the crotch portion 40 is sufficiently low that the crotch portion 40 will stretch in response to wearer movement rather than causing the skin to move. More preferably the stretch modulus in at least one of the longitu~lin~l and the transverse directions is equal to or 1ess than about 300 grams/inch (118 grams/cm), still more preferably the stretchmodulus of the crotch portion in both the longit~ in~l and transverse directions is equal to or less than about 180 grams/inch (71 grams/cm). A method to measure the stretch modulus of a material is described in the TE~ST METHODS section below.
An additional benefit of the soft, flexible crotch portion 40 of the present invention is that the Applicants have found the crotch portion 40 to be less noisy than ll.ensL~ual undely,almelll~ having a nonPl~etic crotch portion as are typical of the art.
Red~1cecl noise provides additional discretion to a wearer when she is wearing such a menstrual undel~ all~lenL 20. The elastically extensible crotch portions of the present invention are less noisy because they are less stiff and more clothlike than a nonelastic crotch portion. It is well kno~,vn in the art that stiffi~ss and noise gelleralion are closely related for a material. That is, stiffer materials are more noisy than less stiff materials when they are bent (e. g. by bodily movement). For example, when a crotch portion 40 of the present invention was evaluated for peak bendingstiffi-~ce accol~lin~ to the CIRCULAR BEND PROCEDURE described in U.S.
Pâtent 4,950,264, issued to Osborn on August 21, 1990 ~the disclosure of which is incorporated herein by r erc,ence)~ the peak bending ~l;rr..e jc was lower than the measurement threshold of the appaldL~ls. By co"",a,ison, the crotch portion of acommercially available menstrual undel~allllenl (KOTEX~) PERSONALS from Kimberly Clark Corp. of Neenah, WI), which is not treated to be elastically b~c, was found to have a peak be.ldillg stiffness of about 24 grams. Such a di~cience in ~ r..cs. sllgf~este that the menstrual undergarment of the present invention will be less noisy, hence more discreet.
The crotch portion 40 preferably co",~,ises a fluid resistant garment surface 42and a hydlophilic body surface 44. Such a structure in the crotch portion 40 allows the menstrual undclg~l"clll 20 to absorb any bodily fluids that may leak around the pe,il~he.y of any c~t~m~ni~l device 80 disposed thereon while, at the same time,resisting leakage of such absorbed fluids therethrough so st~ining of a wearer'sclothing or bedding is ~ ll;7f~l CA 022~7278 1998-12-02 W O97/46198 PCT~US97/09568 Figure S is a cross sectional view along section line 1 ~ of Figure 3. Figure S
shows one plefe,-ed embodiment of the crotch portion 40 aimed at providing the plefelled co---l,ill~lion of bi-directional elastic extensibility, a fluid resistant gar~nent surface 42 and a hydl~philic body surface 44. The embodiment shown in Figure 5 comprises an abso.benl body layer 46 and a fluid resistant barrier layer 48. At least a portion of the body layer 46 comprises the body surface 44 and at least a portion of the barrier layer 48 comprises the ~,~u,..e,-l surface 42. The body layer 46 is soft and provides a co~fo~lable tactile feel to those portions of a wearer's body which it contacts. The body layêr 46 is also absorbênt, so that any bodily fluids that may leak around the periphery of a c~t~m~ni~l device 80 that may be disposed thereon are contained within the menstrual undergarment 20. The barrier layer 48 resists penetration of any adsorbed fluids through the crotch portion 40 that may contact the g~l ~nenl surface 42 thereof to help prevent staining of garments, bedding and the like.
At least one of the body layer 46 and the barrier layer 48 is elastically eYt~n~ihle in the transverse direction, preferably both the lon~ lin~l and the transverse directions, to provide the crotch portion 40 with the requisite elastic eYtçn~ihility.
Preferably, both the body layer 46 and the barrier layer 48 are elastically extensible. If only one of the body layer 46 and the barrier layer 48 is elastically extensible, the yield value of the other ~ement should be sufficiently low so as not to prevent the crotch portion 40 from responding to the full range of body movements.
In the embo~im~nt shown in ~igure 5, the body layer 46 comprises a knitted~
cotton con~ ng m~teri~l P~ère,~bly, the body layer 46 is knit concurrently with k.,;~ p, the shêll portion 30 ofthe menstrual undergarment 20 as is described above.
More p,eft;-~ly, the crotch portion 40 is knit so as to provide the body layer 46 with longit~--lin~lly oriented rugosities or ribs whereby such ribs encourage longitu~in~11y directed flow of any liquids that may be deposited on the body layer 46 by leakage around the pelil~he~y of the c~t~nn~ni~l device 80. Such longit~l-lin~lly directed flow helps utilize the absorbent capacity of the body layer 46 more fully helping to insure that loca}ized areas thereof are not prematurely saturated. Such structures are described in ad~itiQn~l detail in the above-mentioned U.S. Patent 3,985,004.
As also can be seen in Figure 5, the barrier layer 48 preferably comprises a l~min~te of a barrier film 47 and fabric outer layer 49. While a barrier layer 48 ~ co---~ ,ing only a barrier film 47 provides sufficient barrier properties to the crotch portion 40, the addition of the fabric outer layer 49 provides the menstrual undel~almelll with a pleasing clothlike feel and appearance. The barrier layer 48 is W O97/46198 PCT~US97/09568 ~xten~ible, preferably elastically extensible at least in the transverse direction and, more preferably, in both the longitu-lin~l and transverse directions.
The barrier film 47 is subst~nti~lly impervious to liquids (e.g., menses) and ispreferably m~n~f~t~lred from a thin plastic film, although other flexible liquidimpervious materials may also be used. As used herein, the terrn "flexible" refers to materials which are con",lianl and will readily conform to the general shape andcontours of the human body. The barrier film 47 prevents the exudates absorbed by the body layer 46 from wetting articles which contact the menstrual undergarment 20 such as pants, ps~jA~ and bedding. The barrier film 47 may thus comprise a wovenor nonwoven material, polymeric films such as thermoplastic films of polyethylene or polypropylene, or composite materials such as a film-coated nonwoven material.
Preferably, the barrier film 47 is a polyethylene film having a thickness of from about 0.012 mm (0.5 rnil~ to about 0.051 mm (2.0 mils). Exemplary polyethylene films are m~nllf~ctl~red by Clopay Corporation of Cincinn~ti~ Ohio, under the deeign~tion P18-1401 and by Ethyl Col~olalion, Visqueen Division, of Terre Haute, Tnr1i~n~, under the de~ign~tion XP-39385. Particularly pl~rellt;d is the microporous polyethylene film available from Clopay as code 950-92804. Such a microporous polyethylene film has the ~d~itiQn~l advantage of helping to make the crotch portion 40 breathable(di~cu~sed further below).
The fabric outer layer 4g provides an aesthetically pleasing, clothlike feel andappea.allce to the crotch portion 40 of the menstrual undergarment 20. The fabric outer layer 49 can colll~,;se any woven or a nonwoven fabric having suitable feel and appe&l~lce. r~f~,~ably, the fabric outer layer 49 comprises a nonwoven fabric. There are a ,lu,l,l,.,r of m~mlfact~lring techniques which may be used to m~mlf~ctllre the fabric outer layer 49. For example, the fabric outer layer 49 may be a nonwoven web of fibers s~unl)ollded, carded, wet-laid, meltblown, hydroent~ngler1, combinations of the above, or the like. Suitable materials for the fabric outer layer 49 includepolyethylene, polypropylene, rayon, nylon, materials of natural origin, such as cotton, and other similar materials. A p-t;rell~;d fabric outer layer 49 comprises a spunbonded polyethylene nonwoven material having a basis weight of about 30 grams per square meter that is available from Corovin GmbH of Penne? C.,..,la--y.
The barrier film 47 and the fabric outer layer 49 can be l~min~ted to form the barrier layer 48 using means known to those skilled in the art. For example, polymer for forming the barrier film can be provided in molten form and extruded onto the fabric outer layer 49 rc,.llih.g the i~min~te of the barrier layer 48. The barrier film 47 CA 022~7278 1998-12-02 W O97/46198 PCTrUS97/09568 and the fabric outer layer 49 can also be joined using adhesive means such as a uniform continuous layer of adhesive, a patterned layer of adhesive, or an array of separate lines, spirals, or spots of adhesive. Suitable adhesives are m~nllf~ct~red by Findley Adhesives Inc. of Wauwatosa, wr. Particularly pl~fe.led is the hot melt adhesive available from Findley under the de~i~n~tion 2120. The ~tt~chm~nt meanswill prerel~ly co---~-ise an open pattern network of fil~m~nts of adhesive as isdisclosed in U.S. Patent 4,573,986, which issued to Minetola et al. on March 4, 1986, more preferably several lines of adhesive fil~mPnt~ swirled into a spiral pattern such as is illustrated by the app~dl~s and methods shown in U.S. Patent 3,~11,173 issued to Sprague, Jr. on October 7, 1975; U.S. Patent 4,785,996 issued to Ziecker, et al. on November 22, 1978; and U.S. Patent 4,842,666 issued to Werenicz on June 27, 1989. Each of these patents is incorporated herein by reference.
In order to insure breathability (disc--s.~ed below) is not compromised by the means used to 1~ e the barrier film 47 and the fabric outer layer 49, the adhesive used for lA.,~ g the barrier film 47 and the fabric outer layer 49 is applied in a pattern that bslqnces ply bond ~ lh and air permeability. Particularly prefell~d is to apply the l~ g adhesive in a lattice pattern which maximizes open area for breathability. The Applicants have found that an adhesive pattern which covers between about 10 percent and about 40 percent of the area of the crotch 40 provides a s~tief~ctory balance of l~ on S~ ~;"g~}l and l~rea~llability. Preferably, the adhesive should cover between about 10 percent and about 30 percent of the area of the crotch portion 40. Alternatively, the ~tt~chment means may comprise heat bonds, pressure bonds, ul~lasOl~c bonds, dynamic ...~ ical bonds, or any other suitable~tf~chm~nt means or col"binalions of these att~chm~nt means as are known in the art.
As is noted above, the crotch portion 40 is pre~erably e~t~ ly ~y-t~n~ihle in atleast the transverse direction with a stretch modulus equal to or less than the modulus of a ~ skin. Elastic ~Ytç~ bilily can be provided to the crotch portion 40 by the body layer 46, the barrier layer 48 or a combination of the body layer 46 and the barrier layer 48. Preferably, elastic extensibility is provided to the crotch portion 40 by one of the body layer 46 or the barrier layer 48. In the p~e~l-ed embodiment shown in Figure 5, elastic ~Yten~ibility is provided by the body layer 46, specifically by the LYCRA component of the body layer 46. As can be seen in Figure 4, the knit pattems used for the crotch portion 40 (courses at 62 and 64) and the inclusion of LYCRA yams therein combine to provide the crotch portion 40 with bi-directional elastic ~ nQ~ ity~ That is, the LYCRA yams are elastically extensible and the knit -CA 022~7278 1998-12-02 patterns cause the LYCRA yarns to follow a path that has both longittl~lin~l andtransverse components.
As indicated above, a p-Gfe--~d structure for the crotch portion 40, as shown inFigure 5, calls for the body layer 46 to provide the elastic extensibility. This means that the stretch modulus of the barrier layer 48 should be lower than the stretch modulus of the body layer 46. One way to insure that the stretch modulus of the barrier layer 48 is lower than the stretch modulus of the body layer 46 in the transverse direction is to provide the barrier layer 48 with longitlltlin~lly oriented mS~o~itieS or ridges wherein the body layer 46 and the barrier layer 48 are joined so that the rugosities provide "slack", insuring that the stretch modulus of the body layer 46 is higher in the transverse direction. Such rugosities can be provided by inclci...e.~lly stretching the l~min~te of the body layer 46 and the barrier layer 48 accolding to the method described in com~nonly assigned U.S. Patent 5,167,897, issued to Weber, et al. on December 1, 1992, the disclosure of which is incorporated herein by ~ ence.
Alternatively, if bi-directional elastic .oYtçn~ibility is desired, the barrier layer 48 may co.,~";se a structural elastic-like film (SELF) web. A SELF web is an .oxten~ible material that exhibits an elastic-like behavior in the direction of elongation without the use of added elastic materials. The SELE~ web includes a strainable network having at least two contiguous, fli~tinct~ and fli~eimil~r regions. One of the regions is configured so that it will exhibit resistive forces in response to an applied axial elongation in a direction parallel to the predetermined axis before a substantial portion of the other region develops ~ignific~nt resistive forces to the appliedelongation. At least one of the regions has a surface-pathlength which is greater than that of the other region as measured subs~nti~lly parallel to the predetermined axis while the material is in an l~ntçn~ioned condition. The region ~hibiLillg the longer surfiace-p~thlen~h inri~ldec one or more d~ro..l.alions which extend beyond the plane of the other region. The SELF web exhibits at least two ~i~nific7~ntly di~re.~ stages of controlled resistive force to elongation along at least one predetermined axis when subjected to an applied elongation in a direction parallel to the predetermined axis.
The SELF web exhibits first resistive forces to the applied elongation until theelongation of the web is sufficient to cause a substantial portion of the region having the longer surface-p~thl~ngth to enter the plane of applied elongation, whereupon the SELF we1o exhibits second resistive forces to further elongation. The total resistive forces to elongation are higher than the first resistive forces to elongation provided by the first region. Thus, by:

CA 022~7278 1998-12-02 W O 97/46198 PCTrUSg7/09568 1) controlling the area of the region having the shorter surface-pathlength suchthat the slope of the stress/strain curve describing the relationship between the first resistive forces and elongation (i. e. the stretch modulus) is less than the modulus of the body layer 46; and 2) controlling the pattern of the regions having the shorter surface-pathlength such that the first resistive forces have a vector component in both the long~ in~l and the transverse directions (e. g. a chevron, or other diagonally oriented pattern);
a barrier layer 48 having a stretch modulus lower than the body layer 46 in both the ngit--~in~l and the transverse directions can be provided. Alternatively, patterns that provide low modlllllc stretch in either the lon~it~-fiin~l or the transverse directions can also be used. SELF webs suitable for the present invention are more completely described in commonly ~csi~ned U. S . Patent 5,518,081 issued in the name of Chappell, et, al. on May 21, 1996, the ~i~closnre of which is incorporated herein by Ie~elence.
The body layer 46 and the barrier layer 48 are joined at least about the periphery 41 to form the crotch portion 40. Preferably, in order to maximize body fit of the crotch portion 40, the body layer 46 and the barrier layer 48 are joined in the following n~am,e.. 1) the body layer 46 is stretched longitu-lin~lly about 25% and transversely between about 125% and about 150% and an adhesive material, such asmateria1 number 1524 available from 3M, Saint Paul, MN, is applied thereto in a pattern similar to that used to l~min~te the barrier film 47 and the fabric outer layer 49, 2) the barrier layer 48 is disposed on the adhesive treated body layer 46 and adhered thereto by the application of pressure (e. g. by a nip between a roll pair or the like). Alternatively, the ~tt~hment means may co.,.l.lise heat bonds, pressure bonds, ultrasonic bonds, dynamic m~ch~nir~l bonds, or any other suitable ~tt:lchment means or con~bil,alions of these ~tt~r~hm~nt means as are known in the art.
Figure 6 is a cross sectional view of an alternative p. efel . ed embodiment of the crotch portion 40 that is similar to Figure 5. The embodiment shown in Figure 6 also provides a crotch portion 40 with the pl~;rt;.-ed combination of bi-directional elastic ~xtçn.cibility, a fluid l~ g~ surface 42 and a hydrophilic body surface 44.
The crotch portion 40, as shown in Figure 6, c~ lises a body layer 146 and a barrier layer 148 wherein an abso-l,~ body layer 146 is disposed on a barrier layer 148 which has been treated to provide the requisite fluid rcsict~nce. At least a portion CA 022~7278 1998-12-02 W O97/46198 PCT~US97/09568 of the body layer 146 comprises the body surface 44 and at least a portion of the barrier layer 148 comprises the garment surface 42. The embodiment of the present invention shown in Figure 6 takes advantage of the simple method of treating a panty blank ~,vith a fluorocarbon material for providing liquid re~i~t~n~e to the shell portion 30 and the crotch portion 40 that is ~i~c.-.e.sed above.
The body layer 146 ofthe embodiment ofthe present invention shown in Figure 6 is soft, absorbent, and ble,lLl.able. The body layer 146 can comprise any woven or a nonwoven fabric having suitable feel and appearance. Preferably, the body layer 146 comprises a nonwoven or knit fabric. Fibers or yarns suitable for fabrication into the body layer 146 include: polyolefin fibers, such as polyethylene or polypropylenefibers, that have been treated to be hydrophilic; nylon fibers, acetate fibers, acrylic fibers, and rayon fibers (Since such fibers are of intermediate wettability--i.e. they have a critica1 surface tension of between about 40 dynes per centimeter and about 50 dynes per c~ elçr, they may require ~ n"~,,l with a surfactant for optimum utility as a component of the body layer 146); and fibers of natural origin, such as cotton. The body layer 146 can also co-l-p- ise fibers or yarns having elastic extensibility, such as LYCRA, if such elastic ~ .;bility is desired for the body layer 146. More prere.ably, the body layer 146 comprises a knit fabric having substantially the same knit pattern shown at 64 and 66 in Figure 4, wherein at least a portion of the fabric comprises cotton yarns.
As noted above, a panty blank can be treated to provide the crotch portion 4 with liquid r~ nce. That is, by treating a panty blanlc to become liquid resict~nt~
the barrier layer 148 of the embodiment shown in Figure 6 is treated to be liquid rÇcict~nt Materials suitable for L~e~ ~ the barrier layer 14B for providing liquid r~ciet~n~e are s ~bst~nti~lly the same as those suitable for treating the shell portion 30 to provide liquid ~ nce That is, suitable materials include fatty acid or fatty alcohol derivatives, silicones, polyurethanes and fluorocarbons. Particularly p.ere..ed are fluorocarbon materials such as the above mentioned materials from DuPont and3M. Treating an entire panty blank to provide liquid resistance to both the shell portion 30 and the crotch portion 40 (i. e. the barrier layer 148) has been described above. Alternatively, the fluorocarbon material can be selectively applied to only the barrier layer 148 using means such as p?(d-iing or spraying a solution (or emulsion or suspension) of the fluorocarbon material onto the barrier layer 148 and allowing the fluorocarbon material to dry thereon.

CA 022~7278 1998-12-02 W O 97/46198 PCT~US97/09568 The body layer 146 and the barrier layer 148 are joined at least about the periphery 41 of the crotch portion 40 using means known to the art. For example, the body 1ayer 146 can be stitched to the barrier layer about the periphery 41 of the crotch portion 40 or the body layer 146 and the barrier layer 148 can be adhesively joined. r'lt;fe-~bly, the body layer 146 and the barrier layer 148 are stitched about the periphery 41 to form the crotch portion 40 of this alternative pl ert;l . ed embodiment.
Further, while ~ tic~lly extensible crotch portions 40 having a fluid It;si~
gal---~ surface 42 and a hydrophilic body surface 44 provide the desirable )pc~ lies of leak ~ e and wearer con ~ll, one particularly preferred embodiment of the present invention also contemplates providing breathability to the crotch portion 40 for improved C~lllfi~l~ to a wearer. That is, the air permeability of the crotch portion 40iS greater than about 25 ~cubic feet per minute per square meter (0.7 cubic meters per minute per square meter). More preferably, the air permeability is greater than about 35 cubic feet per minute per square meter (1 cubic meter per minute per square meter). A material can be provided with both fluid r~cict~nce and air permeability by either treating an already fluid resistant material to become air permeable or treating an already air permeable material to become fluid rç~ . " For example, a fluid resistant film could be provided with apertures large enough toprovide the requisite air permeability yet small enough to resist fluid transport therethrough (e. g. the microporous polyethylene film from Clopay dicc~-cced above) or an air permeable material could be treated to cause a surface thereof to become hydrophobic so fluid penetration therethrough is resisted without oc-.hlrling any apertures which may provide air permeability (e. g. by tre~trnçnt with a fluoro~he~;~ ~1 as ~iccll~sed above).
Fl~stici7ed Leg Oy~.fi~
As can be seen in Figures 1~, the menstrual undergarment 20 of the present invention is also provided with a pair of elasticized leg openings 34. As noted above, the shell portion 30 and the crotch portion cooperate to define the periphery of each leg opening 34. This periphery is provided with a leg elastic 35 for elasticization of 0 the opening 34. The leg elastics 35 both provide a seal against leakage of bodily fluids about the periphery of each leg opening and cooperate with the shell portion 30 and the crotch portion to provide a "z-direction" biasing force to the crotch portion 40 throughout the full range of wearer movement. That is, the shell portion 30, the crotch portion 40 and the leg elastics 35 cooperate to provide a catamenial device 80 that may be disposed on the crotch portion 40 with a uniform upward force against CA 022~7278 1998-12-02 the distal edges of a wearer's labia majora. As is shown most clearly in Figures 1 and 2, the high cut nature of ~he leg opening 34 also is designed to direct the contractive force of the leg elastics 35 in a more vertical direction than would be possible if a more circular shape would be used for the leg opening 34. Also, as shown most clearly in Figure 3, this high cut shape for the leg opening 34 allows the shell portion 30 to extend between the leg elastics 35 and the crotch portion 40 almost to thetransverse centerline T. That part of the shell portion 30 that is disposed between the leg elastics 35 and the crotch portion 40 is particularly able to respond to wearer movements because the shell portion 30 has a lower stretch modulus than the crotch portion 40. As a result there is improved co-~lroll because the shell portion 30requires a lower force to stretch than the crotch portion 40. There is also a reduction in movement of any c~ F ~ device 80 that may be ~tt~ched to the crotch portion 40 because the shell portion 30 stretches in response to wearer movement rather than the crotch portion 40.
W71ile the leg elastics 35 must provide a minim~1 contractive force help to sealthe periphery of the leg opening 34 against leakage of bodily fluids, it is important that the contractive force not be so great as to cause discomfort to a wearer. The Applicants have found that a contractive force of at least about 20 grams is necessary to .~ e the risk of gapping around the periphery of the leg opening 34.
Preferably the contractive force should be at least about 40 g~ams. More preferably, the contractive force should be at least about 80 grams. ~i~.;..li~.;..g the stretch modulus over the range of expected elastic extensions during the wear cycle also?s the risk of wearer disco~ l. That is, if the leg elastics are desi~nçd to provide a contractive force of about 80 grams at a typical in use extension, that force should not s~ s~ y i,l.,l~.ase for greater extensions that may either be due to a .l,ll'e~ wearer leg circu..~.e.lce or due to wearer movement. The Applicants have found that a stretch modulus for the leg elastics between about 540 grams/inch (213 grams/cm) and about S90 grams/inch (232 grams/cm) provides a good balance between ~ ;.n~ leakage resict~nce and .-~;..;...;,.;..g wearer discomfort.
Pleft;l~bly, the stretch modulus of the leg elastics is between about 550 grams/inch (216 grams/cm~ and about 580 grams/inch (228 grams/cm). Methods for measuring elastic contractions and stretch modulus is given in the TEST METHODS section below.
The leg elastics 35 can be joined to the shell portion 30 and the crotch portion40 about the periphery of the leg opening 34 using means known to those in the art.
For c,~lmple, the leg elastics 35 can be30ined to the shell portion 30 and the crotch CA 022~7278 1998-12-02 WO 97/46198 PCT~US97/09568 portion 40 using adhesive means or by mechanical means, such as ssitc.hing For the plerel,t;d knit menstrual undergarment 20 of the present invention, the leg elastics 35 are preferably joined to the shell portion 30 and the crotch portion 40 by stitchin~
thereto.
~ Optional Features The crotch portion 40 can optionally be provided with indicia to help a wearer optimally position a c~t~meni~l device 80 in the crotch portion 40. For example, such indicia can comprise markings on the leg elastics that would allow a wearer to properly locate any flaps that may be provided on a catamenial device 80 for usetherewith. Alternatively, such indicia could comprise markings along the lon~it~ in~l centerline L that would allow a wearer to reliably position a c~t~m~ni~l device 80 each time a new device is disposed on the body surface 44 of the crotch portion 40.
The present invention also co..le...l)la~es a cont~inmçnt system for control of bodily fluids wherein a menstrual undergarment 20 as described above and a ~t~m~ni~l device 80 act as a unit for control of menstrual flows. Using control of menses as an example, the c~t~meni~l device 80 could be made extensible, ~le~,~bly elastically ~Yten~ible, with a low modulus (co,--pa-~ble to that of a wearer's skin) further ~nh~ncin~ the body cO"ro.l,.,~y l)lol,c,Lies of the menstrual undergarment 20 that are ii~c~ ed above. C'~t~men;~l devices having such elastic extensibility are described in commonly ~c~i nec~ U. S. Patent application Serial No. 07/915,133, filed in the name of Osborn, et al. on July 23, 1992, now pending as U. S. Patent application Serial No. 08/503,895, filed on July 18, 1995 (allowed, no number ~igned) and published as PCT application Serial No. WO 93/01785 on February 4, 1993 and in commonly ~c~i~ned U. S. Patent application Serial No. 07/915,284, filed in the name of Osborn, et al. on July 23, 1992 and published as PCT application Serial No. WO 93/01786 on February 4, 1993, the disclosure of which is incorporated herein by ,-,f~ .,e. Other means whereby the menstrual unde~ cnl 20 and the c~ l device co-operate to better control menstrual flow, such as providing comple-"r~ y ~ hmen~ means to the menstrual undergarment 20 and the c~ i device 80 are also conle,~lplated It would also be obvious to one skilled in the art that other bodily fluids, such as urine and the like could be controlled using similar systems.
The menstrual undergarment 20 of the present invention is used by removing any release liner that may be provided to the catamenial device 80 and therea~ter W O 97/46198 PCT~US97/095~8 placing the catamenial device 80 in the menstrual undergarment 20 on the body surface 44 thereof using s~ffi~ient pressure to insure that any releasable adhesive that may be provided is adhered thereto. If the c~t~meni~l device 80 is also provided with flaps, the user positions the c~ device 80 so that such flaps drape over the edges of the elasticized leg openings 34 such that any flap ~tt~chment means that may be provided contact the crotch portion 40 on its garment surface 42. The wearer can then draw the menstrual undergarment 20 on in the conventional manner.

TEST MEIHODS
Air Permeability Intent This method is inten-iefl to measure the flow of air through a material at a defined pressure drop across the material.
Apparatus Air perme~hility tester, available from Albany International Corporation of Albany NY.
Sample r~ lion 1. Cut the sample into an apploxilllate 4 inch X 4 inch (10 centimeter X 10 c~ r) square.
Method Operate the air permeability tester according to the m~nnf~ct~lrer's instructions.
The following briefly su~ ,a- i;~es the operating procedure described therein.
1~ Mount the sample by stretching it sufficiently taut over the outer orifice plate to remove any distortions that may impede or distort the air flow. The sample is mounted such that the less open side, if the sample is determined to have such, faces toward the mounting plate.

CA 022~7278 1998-12-02 W O97/46198 PCTrUS97/09568 2) Determine the a,oplup~iate inner orifice to provide the proper air flow for the sample being tested. Record the number of the orifice plate used for ev~lu~ting the sample.

3) Ad~ust the fan motor speed to provide a pressure drop of 0.5 inches of water (1.27 centimetçrs of water)across the inner orifice.

4) Record the pressure drop across the sample.
C~lc.~ t;Qn and Report Using the tables provided by the m~n-lf~ct~lrer, the orifice plate number and the pressure drop across the sample, determine the air flow through the sample. Report the mean and standard deviation for each sample eval--~terl Stretch Modulus and Elastic Contractions Intent This method is intenrled to quantify a force comparable to the force exerted on a wearer's body by elastically extensible materials that may be used in an undelgal."t;"~ over an extension range cO~l~pal&ble to that seen in the wear cycle of an unde.ga"lle.l~.
Method The method described in INDA (Association of Nonwoven Fabric Industry) Standard Test 110.1-92 is suitable. The following set up conditions are used:
Gage T.~n~h 2 inches (5.0~ centimeters) Cros.chead Speed: 10 inches/minute (25.4 centimeterslminute) Tensile Testing Machine: App,~,p,ia~e for expected force range, a Model and Load Cell 5564, available from Instron Corporation, Canton, MA is suitable W O 97/46198 PCT~US97/09S68 Sample Width: 1 inch (2.54 c~ntimet~rs) For samples less than inch (2. 54 cPntimeterS) wide, measure the sample width and adjust the measured force by the ratio of 1 inch (2.54 centimeters) to the measured width.
Sample Size: At least three samples per material tested Calculations Force2s: Force at 25% elongation (grams/inch or grams/cm) Forceso: - Force at 50% elongation (grams/inch or grams/cm) Elastic Contractions = Force2s Stretch Modulus = (Forceso - Force2s)/0.25 Report the mean and standard deviation for elastic contractions (leg elastics only) and for stretch modulus The disclosures of all patents, patent applications (and any patents which issuethereon, as well as any corresponding published foreign patent applications), and publications mentioned throughout this description are hereby incorporated by reference herein. It is e~yles~ly not ?Illmittef1~ however, that any of the doc~ment.c incorporated by reference herein teach or disclose the present invention.
While particular embodiments of the present invention have been illustrated and dcs~,lil,cd, it would be obvious to those skilled in the art that various other changes and mo~iifi~tiQns can be made without departing from the spirit and scope of theinvention It is ll~er~;ror~ int~nded to cover in the appended claims all such changes and modifications that are within the scope of this invention.

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Claims (23)

WHAT IS CLAIMED IS:

1. A tubular knit undergarment for use with an absorbent article, said undergarment having a longitudinal centerline defining a longitudinal direction and a transverse centerline defining a transverse direction, said undergarment comprising:
a breathable, liquid resistant shell portion, said shell portion having an elasticized waist opening;
a crotch portion having a longitudinal length and comprising an absorbent body layer and a liquid resistant barrier layer, said crotch portion being elastically extensible in at least one of said longitudinal and said transverse directions; and a pair of leg openings defined by said shell portion and said crotch portion, each of said leg openings having a periphery, said periphery of each of said leg openings being elasticized to provide a seal against liquid flow past said periphery.

2. An undergarment according to Claim 1 wherein said elasticized leg openings co-operate with said elastic extensibility of said crotch portion to provide a force to bias said absorbent article against a wearer's body.

3. An undergarment according to Claim 1 wherein said crotch portion is breathable.

4. An undergarment according to Claim 1 wherein said undergarment is legless.

5. An undergarment according to Claim 1 wherein said undergarment further comprises a front region and a rear region, said front and rear regions each having first and second transversely opposed longitudinal side edges, at least aportion of said first side edge of said front region being joined to said first side edge of said rear region and at least a portion of said second side edge of saidfront region being joined to said second side edge of said rear region by a pairof transversely opposed seams.

6. An undergarment according to Claim 5 wherein said undergarment has a longitudinal length and transverse end edges in each of said front and rear regions when said seams are opened and said undergarment is laid fully flat out in plan view said longitudinal length of said crotch portion being greater than about 50% of said longitudinal length of said undergarment.

7. An undergarment according to Claim 6 wherein said crotch portion has an apexin said front region and an apex in said rear region and the distance along saidlongitudinal centerline between said apex in said rear region and said rear end edge is less than the distance along said longitudinal centerline between said apex in said front region and said front end edge.

8. An undergarment according to Claim 3 wherein at least a portion of said bodylayer comprises an absorbent cotton material and said barrier layer comprises anextensible laminate of a nonwoven web and a breathable film web.

9. An undergarment according to Claim 1 wherein at least a portion of said bodylayer comprises an absorbent cotton material and said barrier layer is treated with a material to increase the contact angle of liquids disposed thereon.

10. An undergarment according to Claim 9 wherein said cotton material is integrally knit into said crotch portion.

11. An undergarment according to Claim 1 wherein said crotch portion further comprises indicia to aid in proper placement of said catamenial device.

12. An undergarment according to Claim 1 wherein said crotch portion is elastically extensible in both of said longitudinal and said transverse directions.

13. An undergarment according to Claim 12 wherein at least a portion of said body layer comprises an absorbent cotton material and said barrier layer comprises anextensible laminate of a nonwoven web and a breathable film web.

14. An undergarment according to Claim 12 wherein at least a portion of said body layer comprises an absorbent cotton material and said barrier layer is treated with a material to increase the contact angle of liquids disposed thereon.

15. An undergarment according to Claim 1 wherein said undergarment is further provided with a front region and a rear region and said crotch portion is provided with a transversely oriented seam joining said front and rear regions.

16 An undergarment according to Claim 15 wherein said crotch portion has an apex in said front region and an apex in said rear region and the distance alongsaid longitudinal centerline between said apex in said rear region and said waistband in said rear region is less than the distance along said longitudinal centerline between said apex in said front region and said waistband in said front region.

17 A legless, tubular knit undergarment for use with an absorbent article, said undergarment having a longitudinal centerline defining a longitudinal direction,a transverse centerline defining a transverse direction, a front region, and a rear region, said undergarment comprising:
a breathable, liquid resistant shell portion having an elasticized waist opening, wherein that part of said shell portion that is disposed of said front region has first and second transversely opposed longitudinal side edges and that part of said shell portion that is disposed of said rear region has first and second transversely opposed longitudinal side edges, at least a portion of said first side edge of said front region being joined to said first side edge of said rear region by a first seam and at least a portion of said second side edge of said front region being joined to said second side edge of said rear region by a second seam;
a breathable, liquid resistant crotch portion comprising an absorbent body layer and a liquid resistant barrier layer, said crotch portion being elastically extensible in said transverse direction; and a pair of leg openings defined by said shell portion and said crotch portion, each of said leg openings having a periphery, said periphery being elasticized to provide a seal against liquid flow past said periphery, wherein said elasticized leg openings co-operate with said elastic extensibility of said crotch portion to provide force to bias said absorbent article against a wearer's body

18. An undergarment according to Claim 17 wherein at least a portion of said body layer comprises an absorbent cotton material and said barrier layer comprises anextensible laminate of a nonwoven web and a breathable film web

19. An undergarment according to Claim 17 wherein at least a portion of said body layer comprises an absorbent cotton material and said barrier layer is treated with a material to increase the contact angle of liquids disposed thereon.

20. An undergarment according to Claim 18 wherein said cotton material is integrally knit into said crotch portion.

21. An undergarment according to Claim 18 wherein said treatment material is selected from the group comprising: fluorocarbon materials, silicone materials, and waxy coatings.

22. A system for containment of bodily fluids, said system comprising:
a tubular knit undergarment, said undergarment having a longitudinal centerline defining a longitudinal direction and a transverse centerline defining a transverse direction, said undergarment comprising:
a breathable, liquid resistant shell portion, said shell portion having an elasticized waist opening;
a breathable crotch portion comprising an absorbent body layer having a body surface and a liquid resistant barrier layer, said crotch portion having a longitudinal length, a transverse width and being elastically extensible in at least one of said longitudinal and said transverse directions; and a pair of leg openings defined by said shell portion and said crotch portion, each of said leg openings having a periphery, said periphery of each of said leg openings being elasticized to provide a seal against liquid flow past said periphery; and an absorbent article disposed on said body surface.

23. A system for containment of bodily fluids according to Claim 22 wherein said elasticized leg openings co-operate with said elastic extensibility of said crotch portion to provide a force to bias said absorbent article against a wearer's body