WO2001035889A1

WO2001035889A1 - Body fluid sealing gaskets for absorbent articles

Info

Publication number: WO2001035889A1
Application number: PCT/US2000/027321
Authority: WO
Inventors: Hannong Rhim; Jennifer Leigh Singletary
Original assignee: Kimberly-Clark Worldwide, Inc.
Priority date: 1999-11-15
Filing date: 2000-10-04
Publication date: 2001-05-25
Also published as: MXPA02004565A; AR026464A1; AU7751800A

Abstract

An improved fit around leg openings and waist openings of pant-like absorbent garments is achieved using additional filler material around portions of the openings. The filler material is a resilient material that can be either uniform in thickness or can vary in thickness around the waist opening and the leg openings. As a result of the filler portions, flatter areas of contact between the garment and the wearer achieve greater curvature for placement of elastic strips on the garment, thereby relieving pressure on areas of contact having initially high curvature. The resulting garment has a gasket-like fit around the waist opening and leg openings with a reduced likelihood of leaving red marks on the wearer's skin due to tension.

Description

BODY FLUID SEALING GASKETS FOR ABSORBENT ARTICLES

FIELD OF THE INVENTION This invention is directed to a gasket construction around leg openings and waist openings of pant-like, personal care absorbent products, such as adult incontinence wear as well as infant and children's diapers, swimwear and training pants. More particularly, elastic laminate strips are maintained in an appropriate curvature to seal fluid within the personal care product. BACKGROUND OF THE INVENTION

Pant-like absorbent garments, such as diapers and training pants, typically include a pair of leg openings having an elastic portion around each leg opening, and a waist opening having an elastic portion as well. The elastic portions are intended to fit snugly around a wearer's legs to prevent leakage from the garment, yet leakage often persists. A number of different approaches have been taken to reduce or eliminate leakage from absorbent garments. For example, physical barriers, such as elasticized containment flaps, have been incorporated into such absorbent garments. The amount and configuration of absorbent material in the zone of the absorbent garment in which liquid surges typically occur (sometimes referred to as a target zone) have also been modified. A further approach to decreasing body fluid leakage is to increase tension of the elastic portions around each leg opening and the waist opening. The increased tension is often effective, but just as often results in an undesirable red marking on a wearer's skin due to increased pressure on the wearer's skin. Typically, contact area around the wearer's waist and legs has very different curvature from one point to another. Some of the contact area is concave, as in the back middle portion of the waist. Even infinitely large tension would not generate any pressure in such areas. Once a somewhat flat area is sealed with a certain tension, resulting pressure at a more curved point is so much higher, thereby creating the aforementioned red marking.

There is a need or desire for gasket-like leg bands and waist openings for absorbent garments that seal fluid within the absorbent garments without creating an undesirable level of tension around the leg bands and the waist openings. SUMMARY OF THE INVENTION

The present invention is directed to an improved construction of leg openings and waist openings in pant-like absorbent garments, such as diapers and training pants. The resulting garment has gasket-like leg openings and/or waist openings that provide greater leakage protection with more uniform pressure in contact areas of the leg openings and the waist openings.

The invention is achieved by applying selected thicknesses of resilient material between two layers of an outer cover, in less curvaceous, or concave, body contact areas, thereby ensuring more uniform curvature (and more evenly distributed pressure) about the openings. Elastic laminate strips are applied to an outer layer of the outer cover, and are located between the resilient material and the outer layer of the outer cover.

The improved uniformity of curvature provides increased comfort as well as a gasket-like fit about the legs and the waist. As a result, a certain minimum sealing pressure is exerted about the leg openings and the waist opening, even at the flattest areas of contact. Furthermore, the laminate strips are maintained in an appropriate curvature to seal fluid within the absorbent garment.

With the foregoing in mind, it is a feature and advantage of the invention to provide a gasket-like construction of leg openings and/or waist openings for absorbent products that results in greater leakage protection with improved uniformity of pressure in contact areas of the leg openings and/or the waist openings.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a vector diagram of tension and pressure at a point along a curved surface;

Fig. 2 is a front perspective view of an absorbent garment of the present invention:

Fig. 3 is a top plan view of an absorbent garment assembly; Fig. 4 is a cross-sectional view of the absorbent garment assembly between two leg openings, taken along line 4-4 in Fig. 3;

Fig. 5 is a cross-sectional view of an alternate embodiment of the absorbent garment assembly; Fig. 6 is a cross-sectional view of another alternate embodiment of the absorbent garment assembly; and

Fig. 7 is a cross-sectional view of yet another alternate embodiment of the absorbent garment assembly. DEFINITIONS

The terms "breathable film," "breathable laminate" or "breathable outer cover material" refer to a film, laminate, or outer cover material having a water vapor transmission rate ("WVTR") of at least about 300 grams/m²-24 hours, using the WVTR Test Procedure described herein. Breathable materials typically rely on molecular diffusion of vapor, and are substantially liquid impermeable.

The term "liquid-permeable material" or "liquid water-permeable material" refers to a material present in one or more layers, such as a film, nonwoven fabric, or open- celled foam, which is porous, and which is water permeable due to the flow of water and other aqueous liquids through the pores. The pores in the film or foam, or spaces between fibers or filaments in a nonwoven web, are large enough and frequent enough to permit leakage and flow of liquid water through the material.

The term "nonwoven fabric or web" means a web having a structure of individual fibers or threads which are interlaid, but not in a regular or identifiable manner as in a knitted fabric. Nonwoven fabrics or webs have been formed from many processes such as, for example, meltblowing processes, spunbonding processes, air laying processes, and bonded carded web processes. Pulp or cellulose-based webs are also nonwoven. The basis weight of nonwoven fabrics is usually expressed in ounces of material per square yard (osy) or grams per square meter (gsm) and the fiber diameters useful are usually expressed in microns. (Note that to convert from osy to gsm, multiply osy by 33.91.) The term "microfϊbers" means small diameter fibers typically having an average fiber denier of about 0.005-10, preferably about 0.05-6, more preferably, about 1-4. Fiber denier is defined as grams per 9000 meters of a fiber. For a fiber having circular cross- section, denier may be calculated as fiber diameter in microns squared, multiplied by the density in grams/cc, multiplied by 0.00707. A lower denier indicates a finer fiber and a higher denier indicates a thicker or heavier fiber. For example, the diameter of a polypropylene fiber given as 15 microns may be converted to denier by squaring, multiplying the result by .89 g/cc and multiplying by .00707. Thus, a 15 micron polypropylene fiber has a denier of about 1.42 (15² x 0.89 x .00707 = 1.415). Outside the United States the unit of measurement is more commonly the "tex," which is defined as the grams per kilometer of fiber. Tex may be calculated as denier/9.

The term "spunbonded fibers" refers to small diameter fibers which are formed by extruding molten thermoplastic material as filaments from a plurality of fine capillaries of a spinnerette having a circular or other configuration, with the diameter of the extruded filaments then being rapidly reduced as by, for example, in U.S. Patent 4,340,563 to Appel et al., and U.S. Patent 3,692,618 to Dorschner et al., U.S. Patent 3,802,817 to

Matsuki et al., U.S. Patents 3,338,992 and 3,341,394 to Kinney, U.S. Patent 3,502,763 to Hartmann, U.S. Patent 3,502,538 to Petersen, and U.S. Patent 3,542,615 to Dobo et al., each of which is incorporated herein in its entirety by reference. Spunbond fibers are quenched and generally not tacky when they are deposited onto a collecting surface. Spunbond fibers are generally continuous and often have average deniers larger than about 0.3, more particularly, between about 0.6 and 10.

The term "meltblown fibers" means fibers formed by extruding a molten thermoplastic material through a plurality of fine, usually circular, die capillaries as molten threads or filaments into converging high velocity heated gas (e.g., air) streams which attenuate the filaments of molten thermoplastic material to reduce their diameter, which may be to microfiber diameter. Thereafter, the meltblown fibers are carried by the high velocity gas stream and are deposited on a collecting surface to form a web of randomly dispersed meltblown fibers. Such a process is disclosed for example, in U.S. Patent 3,849,241 to Butin et al. Meltblown fibers are microfibers which may be continuous or discontinuous, are generally smaller than about 0.6 denier, and are generally self bonding when deposited onto a collecting surface. Meltblown fibers used in the present invention are preferably substantially continuous in length.

The term "film" refers to a thermoplastic film made using a film extrusion and/or foaming process, such as a cast film or blown film extrusion process. The term includes apertured films, slit films, and other porous films which constitute liquid transfer films, as well as films which do not transfer liquid. The term also includes film-like materials that exist as open-celled foams.

The term "foam material" refers to a thermoplastic layer material made with the aid of a foaming process. The term "open-celled foam material" refers to a foam layer whose cells interconnect, or otherwise create pores from one surface of the layer to the opposite surface.

The term "polymer" includes, but is not limited to, homopolymers, copolymers, such as for example, block, graft, random and alternating copolymers, terpolymers, etc. and blends and modifications thereof. Furthermore, unless otherwise specifically limited, the term "polymer" shall include all possible geometrical configurations of the material. These configurations include, but are not limited to isotactic, syndiotactic and atactic symmetries.

The term "cloth" includes, but is not limited to, a fabric made of fibrous material, commonly a woven fabric of, for example, cotton. Furthermore, the term "cloth" shall also include all nonwoven materials exhibiting a cloth-like feel.

The term "pulp fibers" refers to fibers from natural sources such as woody and non-woody plants. Woody plants include, for example, deciduous and coniferous trees.

Non-woody plants include, for instance, cotton, flax, esparto grass, milkweed, straw, jute hemp, and bagasse. The term "stretchable" means that a material can be stretched, without breaking, to at least 150% of its initial (unstretched) length in at least one direction, suitably to at least 200% of its initial length, desirably to at least 250% of its initial length. "Elastic" materials are stretchable materials that tend to recover or retract most of the way to their initial length when the stretching force is removed. An elastic material should recover at least 50% of the way to its initial length when a stretching force is removed, preferably at least 75%o of the way to its initial length.

The term "superabsorbent" or "superabsorbent material" refers to a water- swellable, water-insoluble organic or inorganic material capable, under the most favorable conditions, of absorbing at least about 15 times its weight and, more desirably, at least about 30 times its weight in an aqueous solution containing 0.9 weight percent sodium chloride. The superabsorbent materials can be natural, synthetic and modified natural polymers and materials. In addition, the superabsorbent materials can be inorganic materials, such as silica gels, or organic compounds such as cross-linked polymers.

The term "cross-linked" refers to any means for effectively rendering normally water-soluble materials substantially water insoluble but swellable. Such means can include, for example, physical entanglement, crystalline domains, covalent bonds, ionic complexes and associations, hydrophilic associations, such as hydrogen bonding, and hydrophobic associations or Van der Waals forces.

The term "personal care absorbent product" includes without limitation diapers, training pants, swim wear, absorbent underpants, baby wipes, adult incontinence products, and feminine hygiene products.

DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS It is well known that pressure exerted from elastic tension at a given body contact point is proportional to the curvature at the point as well as to the amount of tension, as demonstrated by the LaPlace equation:

P_g = σ, R, (1) where P_g is the normal force or gasket pressure, R is the radius of curvature along a wearer's body 5, and σ, is the tension in the tangential direction (see Fig. 1). Thus, higher pressure P„ is generated at a smaller radius R, or higher curvature 1/R, under a given tension σ,.

In pant-like absorbent garments having elasticized leg openings and/or an elasticized waist opening, the elastic tension σ, should be high enough so that sufficient pressure P_g is exerted at all points around the perimeter of the opening, to seal the garment against the wearer's body. Flatter areas of the wearer's body, having very high radii of curvature can only have sufficient pressure P_g exerted by the garment when the tension σ_{ is high. However, this high tension σ_{ must then exist all the way around the opening. Once a flatter area is sealed using a high tension σ,, the pressure ζ at a nearby point of high curvature (low R,) is often so high that it causes a red mark to develop on the skin. Typically, the contact area about a wearer's waist and legs has very different curvature from one point to another. Some contact area is even concave, as in the back middle portion of the waist, such that even infinitely large tension exerted across the area would not generate any pressure there at all. Alleviating any gap between a wearer's body 5 and an absorbent garment 2, or maintaining certain gasket pressure, P_g, on the body 5 minimizes leakage from the absorbent garment 2. As shown in the drawings, and explained further below, resilient filler portions 36 of the present invention are aligned to meet the flatter, or concave, contact portions of the wearer's body 5, thereby creating a higher degree of curvature experienced by leg elastics 38, or waist elastics 40, in the flatter areas of the wearer's body 5. As a result, tension is reduced in the contact areas of the wearer's body 5 having the most curvature, and is redistributed toward areas of lesser curvature. Furthermore, a minimum sealing pressure is exerted about the flatter contact areas of the wearer's body 5.

Referring to Fig. 2, a pant-like absorbent garment 2 of the present invention includes a waste containment section 4 and two side portions 6 and 8 defining a waist opening 10 and a pair of leg openings 12 and 14. The side portion 6 includes stretchable panels 18 and 20 joined together at seam 30. The side portion 8 includes stretchable panels

24 and 26 joined together at seam 33. Seams 30 and 33 extend longitudinally from the waist opening 10 to the leg openings 12 and 14 of the garment 2. The filler portions 36, comprising resilient material, are located within the waist opening 10 and the leg openings 12 and 14 to provide appropriate curvature for placement of the leg elastics 38 and the waist elastics 40 (Figs. 3-7).

The waste containment section 4 includes multiple layers, as shown in Fig. 3, including, for instance, a liquid-permeable body side liner 42, an absorbent core layer 44, a surge layer 46, and a liquid-impermeable outer cover 48 which faces away from the wearer. The waste containment section 4 includes waist elastics 40 on the front and back of the garment 2. The leg openings 12 and 14 also include leg elastics 38 which extend substantially around the portion of the leg openings defined by the waste containment section 4.

A closer examination of the construction of the leg openings 12 and 14 is revealed in Figs. 3-7. The construction of the waist opening 10 is often similar to the construction of the leg openings 12 and 14. In a preferred embodiment, shown in Figs. 3 and 4, the leg elastics 38, or the waist elastics 40, are sandwiched between a cloth layer 50 and a polymer layer 52 of the outer cover 48. The filler portions 36 are also sandwiched between the cloth layer 50 and the polymer layer 52 of the outer cover 48, more specifically with the filler portions 36 sandwiched between the leg elastics 38, or the waist elastics 40, and the cloth layer 50. In an alternate embodiment, as shown in Fig. 5, the filler portions 36 are located on an innermost surface of the polymer layer 52, such that the filler portions 36 are sandwiched between the wearer's skin and the polymer layer 52 while the leg elastics 38, or the waist elastics 40, remain sandwiched between the cloth layer 50 and the polymer layer 52. In another embodiment, the outer cover 48 comprises one layer, preferably the polymer layer 52. In this embodiment, the filler portions 36 can be located on an inner surface of the outer cover 48 with the leg elastics 38, or the waist elastics 40, sandwiched between the filler portions 36 and the polymer layer 52, as shown in Fig. 6. Alternatively, the filler portions 36 can be located on an outer side of the outer cover 48 with the leg elastics 38, or the waist elastics 40, located on an outer side of the filler portions 36, as shown in Fig. 7.

Suitable materials for the filler portions 36 are preferably resilient materials, such as elastomeric material, solid rubber, foam, and bubble wrap, wherein the bubble wrap includes a fluid, e.g. air, that is contained and moves from pressure points to expand in concave areas. The term "resilient" includes any material which can be compressed, and which tends to return to its original shape when relaxed. The filler portions 36 can be located along the entire lengths of the leg elastics 38 and the waist elastics 40, or only in select locations along the lengths of the leg elastics 38 and the waist elastics 40. Similarly, the thickness of the filler portions 36 can either be uniform, or may vary with increased thickness in locations adjacent flatter or concave areas of the wearer's body 5. In order to achieve greatest protection against leakage, the filler portions 36 should be located in such areas and with such thicknesses that snug, but not uncomfortably tight, contact exists between the wearer's body 5 and the absorbent garment 2 about the entire circumference of each of the leg openings 12 and 14 and/or the waist opening 10. In an embodiment wherein the filler portions 36 vary in thickness, the greatest thickness is located in the back middle portion of the waist. The thickness of the filler portions 36 also varies depending on type of garment, location on the garment, and density of the filler material. Preferably, the filler portions 36 are 0.2 inch (0.5 cm) to 4 inches (10 cm) thick, more preferably 0.8 inch (2 cm) to 2 inches (5 cm) thick. The filler portions 36 can be at least as wide as the leg elastics 38 and the waist elastics 40, and are preferably wider.

As mentioned, the uneven pressure problem can be alleviated by using a certain gasket design with fillers of uneven thickness between the elastic bands and the wearer's body. First, the tension σ of the leg elastics 38 and/or the waist elastics 40 is adjusted such that a maximum pressure, P_M, at a point of a smallest radius of curvature, R-_, or highest curvature, 1/R™, is lower than a red-mark-inducing pressure, P_R, as demonstrated in Equation 2:

P_M = σ/R_m < P_R (2) Then, the filler portions 36 having a thickness profile, δ(x), conforming to the wearer's body topology, R(x), are added to the corresponding leg openings 12, 14 and/or waist opening 10 such that the resulting pressure, P(x), at the point of the radius of the body curvature, R(x), increases with the filler portions 36 of thickness δ(x), beyond fluid pressure, P_f, of fluid being maintained in the garment 2, plus the gravitational force, W. In most cases, gravitational force W is zero or insignificant at the waist opening, because the fluid is seldom located above the waist opening unless the wearer is inverted. Gravitational force W on the fluid is a greater factor at the leg openings, where it may approach the fluid mass multiplied by the universal gravitational acceleration constant G, when the wearer is standing.

Mathematically, the filler portions' 36 thickness profile, δ(x), should satisfy the following relationship:

P(x) = σ/{R(x) + δ(x)} > P_f + W (3)

Assuming that:

P_R > P_f + W (4)

This gasket design is particularly effective in the aforementioned areas of concave curvature. Taking into consideration filler portions 36 having uniform initial thickness, δ₀, before being compressed, and certain compression resilience characteristics demonstrated by Equation 5: δ = δ₀ - δ(P)/δ₀ (5) the following equation is satisfied:

P_f + W < σ/[R(x) + δ {P(x)}] < P_R (6)

In other words, the filler portions 36 are more compressed at high pressure at points of higher curvature. Conversely, the filler portions 36 are less compressed at points of lower curvature. Thus, the resulting curvature decrease with such filler portions 36 is greater at the initially higher curvature points, but smaller at the lower curvature points, thereby evening out the resulting pressure.

Equations 2-6 assume uniform tension along the lengths of the filler portions 36. When the absorbent garment 2 is worn, the garment 2 is stretched according to the body's topology, but the stretched tension is generally not aligned with the closure line around the leg or waist. The bottom side of the leg in the middle of the crotch area is typically tensioned high, while the tension is nearly absent on the top side of the leg in the middle of the outer thigh area. Thus, proper placement of the leg elastics 38 generating at least minimum tension along the circumference of the leg openings 12 and 14 is essential.

The filler portions 36 may be attached to the outer cover 48 and/or to the leg elastics 38 and the waist elastics 40 by a variety of techniques including adhesive bonding, ultrasonic bonding, thermal bonding, stitch bonding or other conventional techniques.

Suitable adhesives include spray adhesives, hot melt adhesives, self-adhering elastomeric materials and the like.

In still another embodiment, leg elastics 38 and/or waist elastics 40 can be eliminated from the structure. Filler portions 36 can be placed between the wearer's body and the inner or outermost garment layers so that the garment is held in place primarily by the compressive force exerted by the resilient filler material, and elastic tension is substantially eliminated. In still another embodiment, elastics 38 and/or 40 can have a profiled thickness, effectively incorporating the filler portions 36 into the thicker portions of the elastics 38 and/or 40. The stretchable side portions 6 and 8 can be constructed of conventional woven or nonwoven materials, formed from a wide variety of elastic and stretchable polymers. Suitable polymers include without limitation block copolymers of polystyrene, polyisoprene and polybutadiene; copolymers of ethylene, natural rubbers and urethanes; and combinations of the foregoing. Particularly suitable are styrene-butadiene block copolymers sold by Shell Chemical Co. under the trade name KRATON^®. Other suitable polymers include copolymers of ethylene, including without limitation ethylene vinyl acetate, ethylene methyl acrylate, ethylene ethyl acrylate, ethylene acrylic acid, stretchable ethylene-propylene copolymers, and combinations thereof. Also suitable are coextruded composites of the foregoing, and elastomeric staple integrated composites where staple fibers of polypropylene, polyester, cotton and other materials are integrated into an elastomeric meltblown web. Certain elastomeric single-site or metallocene-catalyzed olefin polymers and copolymers are also suitable for the side portions 6 and 8. As shown in Figs. 2 and 3, the stretchable side portions 6 and 8 are preferably rectangular in shape, and preferably extend from the top of the waist opening 10 to the leg openings 12 and 14. The side portions 6 and 8 may also be laminates of multiple layers, and are preferably breathable to water vapor but impervious to liquids.

When an absorbent garment assembly 3, shown in Fig. 3, is assembled into the absorbent garment shown in Fig. 2, the longitudinal seams 30 and 33 may be formed by conventional methods including, without limitation, ultrasonic welding, thermal bonding, adhesive bonding, stitch bonding and the like. Ultrasonic welding is a presently preferred technique. The various bonding techniques are conventional, and are neither critical nor limiting as to the present invention.

The leg elastics 38 may be attached to the outer cover 48 by a variety of techniques including adhesive bonding, ultrasonic bonding, thermal bonding, stitch bonding or other conventional techniques. Suitable adhesives include spray adhesives, hot melt adhesives, self-adhering elastomeric materials and the like. Often, the leg elastics 38 will be applied in the stretched condition to the outer cover 48, and then allowed to retract, causing gathering of the outer cover 48 when the leg elastics 38 are retracted. The leg elastics 38 preferably comprise at least two elastic bands, more preferably at least four elastic bands. In the vicinity of the waist opening 10, the waist elastics 40 may be attached to or embedded within the garment 2. The waist elastics 40 may include single or multiple elastic bands constructed from any of the same materials as the leg elastics 38. The waist elastics 40 in the front and back of the garment 2 preferably have lengths which are nearly the same, or slightly shorter than the width of the outer cover 48. The waist elastics 40 may be attached to the outer cover 48 using the same techniques described above for attaching leg elastics 38.

A wide variety of elastic materials may be employed for the leg elastics 38 and the waist elastics 40. Examples include a film or meltblown web formed using block or graft copolymers of butadiene, isoprene, styrene, ethylene-methyl acrylate, ethylene-vinyl acetate, ethylene-ethyl acrylate or blends thereof. One preferred elastomer is a block copolymer of styrene-ethylbutadiene-styrene. Specific materials of which the leg elastics 38 and the waist elastics 40 can be made are the Kraton G series from Shell Chemical Company, such as Kraton G-1650, Kraton G-1652, Kraton GX-1657 and preferably Kraton G-2740X. Also, the Kraton D series can be used, as well as polyester elastomeric materials, polyurethane elastomeric materials and polyamide elastomeric materials. Elastomeric single- site or metallocene-catalyzed olefin polymers and copolymers can also be employed. Also, the leg elastics 38 and the waist elastics 40 can be made of an activatable material applied in an unstretched condition, and activated by heat, light or moisture or radiation to cause shrinkage and elasticity. Activatable elastic materials, such as 3M KER-2210 Thermoelastic

Film, can be obtained from the 3M Company.

Each of the leg elastics 38 and the waist elastics 40 preferably has a width of about 0.05 inch (0.13 cm) to about 3 inches ( 7.6 cm), more preferably about 0.15 inch (0.38 cm) to about 1.5 inches(3.8 cm), most preferably about 0.25 inch (0.64 cm) to about 1.0 inch (2.5 cm). Each of the leg elastics 38 and each of the waist elastics 40 preferably has elongation of 25-350%, more preferably about 30-260%, most preferably about 35-200%>. The length of each of the leg elastics 38 should substantially cover the length of the outer cover 48 between the stretchable panels 18 and 24, and between the stretchable panels 20 and 26. Depending on the garment size, the leg elastics 38 may have a length of at least about 2 inches (5 cm), preferably at least about 3 inches (7.6 cm) , more preferably at least about 4 inches (10 cm). The waist elastics 40, also dependent on the garment size, may have a length of at least about 2 inches (5 cm), preferably at least about 3 inches (7.6 cm), more preferably at least about 4 inches (10 cm). The filler portions 36 can have a length which is about equal to, or somewhat longer or shorter than, the length of each coπesponding leg elastic and waist elastic. Each filler portion 36 can have varying thicknesses along its length so that the filler portions 36 are thicker adjacent the flatter portions of the wearer's body 5. As previously indicated, the outer cover 48 may include a single layer, or may include multiple layers joined together. The outer cover 48, as shown in Figs. 4 and 5, includes two layers, the cloth layer 50 and the polymer layer 52, joined by an outer cover adhesive layer 54. The cloth layer 50 of the outer cover 48 can be made from a wide variety of woven or nonwoven material, films, or a film-coated nonwoven material, including, for instance, cast or blown films of polyethylene, polypropylene, polyester or blends thereof. The cloth layer 50 may also be a composite of a bonded carded or spunbonded or meltblown material, for example, a spunbonded-meltblown composite of thermoplastic material or a spunbonded-meltblown-spunbonded thermoplastic material, wherein the spunbonded layer can provide a cloth-like texture and the meltblown layer can provide liquid impermeability. Materials of which the cloth layer 50 can be made include nonwovens having a high basis weight, such as about 0.4 ounces per square yard (13.6 gsm), or greater. The polymer layer 52 of the outer cover 48 can include extruded films of polyolefin polymers or copolymers, or other thermoplastic materials. Generally the outer cover 48 will have a length from about 12 inches (30 cm) to about 30 inches (76 cm), and a width from about 3 inches (7.6 cm) to about 20 inches (51 cm), depending on the wearer's size.

The outer cover 48, absorbent core layer 44, surge layer 46 and body side liner 42 may also be joined together using ultrasonic bonding, thermal bonding, stitch bonding, or any of the adhesive materials described above for the attachment of the filler portions 36, the leg elastics 38 and the waist elastics 40. As shown in Figs. 5 and 6, the end regions of the liner 42 may be tucked between the filler portions 36 and the outer cover 48 and bonded into place. This way, the surge layer 46 and the absorbent core layer 44 are surrounded by the liner 42 and the outer cover 48. The absorbent core layer 44 can be made of wood pulp fluff or a mixture of wood pulp fluff and a superabsorbent material, or a wood pulp fluff integrated with a thermoplastic absorbent material treated with a surfactant. Thermal binders, such as Pulpex^® can be used in blends or layering with the fluff and superabsorbent material. The absorbent core layer 44 can also be a batt of meltblown synthetic fibers, a bonded carded web of synthetic or natural fibers or blends thereof, a composite of meltblown fibers and the like. The synthetic fibers can be, but are not limited to, polypropylene, polyethylene, polyester and copolymers of these or other polyolefms.

Examples of synthetic superabsorbent material polymers include the alkali metal and ammonium salts of poly(acrylic acid) and poly(methacrylic acid), poly(acrylamides), poly(vinyl ethers), maleic anhydride copolymers with vinyl ethers and alpha-olefms, poly(vinyl pyrrolidone), poly(vinylmorpholinone), poly(vinyl alcohol), and mixtures and copolymers thereof. Further superabsorbent materials include natural and modified natural polymers, such as hydrolyzed acrylonitrile-grafted starch, acrylic acid grafted starch, methyl cellulose, chitosan, carboxymethyl cellulose, hydroxypropyl cellulose, and the natural gums, such as alginates, xanthan gum, locust bean gum and the like. Mixtures of natural and wholly or partially synthetic superabsorbent polymers can also be useful in the present invention. Other suitable absorbent gelling materials are disclosed by Assarsson et al. in U.S. Patent No. 3,901,236 issued August 26, 1975. Processes for preparing synthetic absorbent gelling polymers are disclosed in U.S. Patent No. 4,076,663 issued February 28, 1978 to Masuda et al. and U.S. Patent No. 4,286,082 issued August 25, 1981 to Tsubakimoto et al.

Both the surge layer 46 and the body side liner 42 are constructed from highly liquid pervious materials. These layers function to transfer liquid from the wearer to the absorbent core layer 44. Suitable materials include porous woven materials, porous nonwoven materials, open-celled foams, and apertured films. Examples include, without limitation, any flexible porous sheets of polyolefin fibers, such as polypropylene, polyethylene or polyester fibers; webs of spunbonded polypropylene, polyethylene or polyester fibers; webs of rayon fibers; bonded carded webs of synthetic or natural fibers or combinations thereof. Either layer may also be an apertured plastic film. The various layers of the garment 2 have dimensions which vary depending on the size and shape of the wearer. The resulting product is an absorbent garment 2 having a comfortable, gasketlike fit about the leg openings 12 and 14 and the waist opening 10. The filler portions 36 provide improved uniformity of curvature for the leg elastics 38 and the waist elastics 40 in flatter and concave contact areas of the wearer's body 5. The improved uniformity of curvature results in reduced tension in contact areas of high curvature. Furthermore, a certain minimum sealing pressure is exerted about the leg openings 12 and 14 and the waist opening 10, even at the flattest areas of contact. The absorbent garment 2 can be sized and tailored for a wide variety of uses including, for example, diapers, training pants, swimwear, adult incontinence garments, and the like.

WVTR TEST PROCEDURE The following procedure is described for testing of the water vapor transmission rate (WVTR) for the self-regulating films of the invention. The WVTR is measured in a manner similar to ASTM Standard Test Method for Water Vapor

Transmission of Materials, Designation E-96-80 as follows. For the purposes of the present invention, 3 inch diameter (76 mm) circular samples are cut from the test material and from a control material, CELGARD^® 2500 (Hoechst Celanese Corporation). CELGARD 2500 is a 0.0025 cm thick film composed of microporous polypropylene. Two or three samples are prepared for each material. Test cups used for testing are cast aluminum, flanged, 5.1 centimeters deep and come with a mechanical seal and neoprene gasket. The cups are distributed by Thwing- Albert Instrument Company, Philadelphia, Pennsylvania, under the designation Vapometer cup no. 68-1. One hundred millimeters of distilled water is poured into each Vapometer cup, and each of the individual samples of the test materials and control material are placed across the top area of an individual cup. Screw-on flanges are tightened to form a seal along the edges of the cups leaving the associated test material or control material exposed to the ambient atmosphere over a 62 millimeter diameter circular area (an open, exposed area of about 30 cm²). The cups are then weighed, placed on a tray, and set in a forced air oven set at 100°F (38°C). The oven is a constant temperature oven with external air through it to prevent water vapor accumulation inside. A suitable forced air oven is, for example, a Blue M Power-O-Matic 60 oven distributed by Blue M Electric Co. of Blue Island, Illinois. After 24 hours, the cups are removed from the oven and weighed. The preliminary, test WVTR value is calculated as follows:

Test WVTR = [(grams weight loss over 24 hours) x 7571] ÷ 24 The relative humidity within the oven is not specifically controlled. Under predetermined set conditions of 38°C and ambient relative humidity, the WVTR for CELGARD 2500 has been determined to be 5000 g/m²-24 hours. Accordingly, CELGARD 2500 is run as a control sample with each test and the resulting values are coπected in accord with the variation of the control relative to its known WVTR. While the embodiments of the invention described herein are presently preferred, various modifications and improvements can be made without departing from the spirit and scope of the invention. The scope of the invention is indicated by the appended claims, and all changes that fall within the meaning and range of equivalents are intended to be embraced therein.

Claims

WE CLAIM:

1. An absorbent garment, comprising: a waste containment section defining a waist opening and first and second leg openings; and filler portions attached to one side of the waste containment section around at least a portion of each of the first and second leg openings.

2. The absorbent garment of Claim 1 wherein the filler portions comprise an elastic foam.

3. The absorbent garment of Claim 1 wherein the filler portions comprise a resilient material.

4. The absorbent garment of Claim 3 wherein the resilient material comprises a material selected from elastomeric material, foam, bubble wrap, and combinations thereof.

5. The absorbent garment of Claim 1 wherein the filler portions vary in thickness along the portion of each of the first and second leg openings to which the filler portions are attached.

6. The absorbent garment of Claim 1 wherein the filler portions comprise a uniform thickness along the portion of each of the first and second leg openings to which the filler portions are attached.

7. The absorbent garment of Claim 1 wherein the filler portions have a thickness in a range between 0.5 cm and 10 cm.

8. The absorbent garment of Claim 1 wherein the filler portions have a thickness in a range between 2 cm and 5 cm.

9. The absorbent garment of Claim 1 further comprising elastic bands operatively attached to the waste containment section around at least a portion of each of the first and second leg openings.

10. The absorbent garment of Claim 9 wherein the waste containment section further comprises a lining layer and an outer cover layer, such that the elastic bands and the filler portions are sandwiched between the lining layer and the outer cover layer.

11. The absorbent garment of Claim 9 wherein the filler portions are located between the waste containment section and the elastic bands.

12. The absorbent garment of Claim 9 wherein the filler portions are attached to the one side of the waste containment section and the elastic bands are attached to a second side of the waste containment section.

13. The absorbent garment of Claim 1 further comprising filler portions attached to one side of the waste containment section around at least a portion of the waist opening, and elastic bands operatively attached to the waste containment section around at least a portion of the waist opening.

14. An absorbent garment, comprising: a waste containment section defining a waist opening and first and second leg openings; and filler portions attached to one side of the waste containment section around at least a portion of the waist opening.

15. The absorbent garment of Claim 14 wherein the filler portions comprise an elastic foam.

16. The absorbent garment of Claim 14 wherein the filler portions comprise a resilient material.

17. The absorbent garment of Claim 16 wherein the resilient material comprises a material selected from elastomeric material, foam, bubble wrap, and combinations thereof.

18. The absorbent garment of Claim 14 wherein the filler portions vary in thickness along the portion of the waist opening to which the filler portions are attached.

19. The absorbent garment of Claim 14 wherein the filler portions comprise a uniform thickness along the portion of the waist opening to which the filler portions are attached.

20. The absorbent garment of Claim 14 wherein the filler portions have a thickness in a range between 0.5 cm and 10 cm.

21. The absorbent garment of Claim 14 wherein the filler portions have a thickness in a range between 2 cm and 5 cm.

22. The absorbent garment of Claim 14 further comprising elastic bands operatively attached to the waste containment section around at least a portion of the waist opening.

23. The absorbent garment of Claim 22 wherein the waste containment section further comprises a lining layer and an outer cover layer, such that the elastic bands and the filler portions are sandwiched between the lining layer and the outer cover layer.

24. The absorbent garment of Claim 22 wherein the filler portions are located between the waste containment section and the elastic bands.

25. The absorbent garment of Claim 22 wherein the filler portions are attached to the one side of the waste containment section and the elastic bands are attached to a second side of the waste containment section.

26. An absorbent garment, comprising: a waste containment section having front and rear portions, and a central region; first and second side panels, each joined to the front and rear portions of the waste containment section; the waste containment section and side panels defining a waist opening and first and second leg openings; the waste containment section including at least a liquid-permeable body side liner, an absorbent layer and a substantially liquid-impermeable outer cover layer; filler portions attached to one side of the waste containment section around at least a portion of at least one of the waist opening and first and second leg openings; and elastic bands operatively attached to the waste containment section around at least a portion of at least one of the waist opening and the first and second leg openings.

27. The absorbent garment of Claim 26 wherein the filler portions vary in thickness along the portion of the waist opening and along the portion of each of the first and second leg openings to which the filler portions are attached.

28. The absorbent garment of Claim 26 wherein the filler portions have increased thickness along a back middle portion of the waist opening.

29. The absorbent garment of Claim 26 wherein the filler portions comprise a uniform thickness along the portion of the waist opening and along the portion of each of the first and second leg openings to which the filler portions are attached.

30. The absorbent garment of Claim 26, wherein the elastic bands and filler portions are attached around at least a portion of the waist opening and around at least a portion of the first and second leg openings.

31. The absorbent garment of Claim 26 wherein the filler portions have a thickness in a range between 0.5 cm and 10 cm.

32. The absorbent garment of Claim 26 wherein the filler portions have a thickness in a range between 2 cm and 5 cm.

33. The absorbent garment of Claim 26 wherein the filler portions comprise a resilient material.

34. The absorbent garment of Claim 33 wherein the resilient material comprises a material selected from elastomeric material, foam, bubble wrap, and combinations thereof.

35. The absorbent garment of Claim 26 wherein the elastic bands and the filler portions are sandwiched between the body side liner and the outer cover layer.