AU2001257304A1 - Disposable Absorbent Underpants - Google Patents

Description

DISPOSABLE ABSORBENT UNDERPANTS

Field of the Invention

This invention relates to disposable absorbent underpants for containing body fluid. More specifically, this invention relates to disposable absorbent underpants for containing at least 100 grams of urine.

Background of the Invention

Disposable underpants have been commercially available for some time for use by infants and toddlers as diapers and training pants. Disposable underpants have also been available for use by adults suffering from incontinence. A number of such underpants have used elastics around the leg openings to form gathers so as to prevent leakage of body fluid from the underpants. When the elastic completely encircles each of the leg openings, it has been found that pressure marks can be left on the thighs of the wearer should the elastic be too tight. It has also been found that when three or more discrete sections of elastics are secured around each leg opening that at the points where the elastics overlap one another, leakage can occur. The overlap of two sections of elastics can also create a bump or hump that can cause irritation and discomfort to the wearer of the underpants.

Now, disposable underpants have been developed which utilize three or more discrete elastic sections that are spaced apart from one another and are positioned about each leg opening. Each discrete elastic section is separated from an adjacent section by a gap. The gaps formed between the adjacent sections assures that the elastics will not overlap one another even when the elastics contract and gather the material to which they are secured. By eliminating overlaps of the elastics around each leg opening, one can prevent the leakage of body fluid from the underpants.

Summary of the Invention

Briefly, this invention relates to disposable absorbent underpants for containing body fluid. The disposable underpants include an outer cover having a front portion and a back portion joined together by a crotch portion. An inner liner is attached to the outer cover. The inner liner has a front portion and a back portion joined together by a crotch portion. The front and back portions of the outer cover and the inner liner are connected together to form a waist opening and a pair of leg openings. An absorbent pad is secured to the crotch portion of the inner liner. The absorbent pad includes a liquid-permeable cover, a liquid impermeable baffle and an absorbent layer positioned therebetween. A first pair of leg elastics is secured between the outer cover and the inner liner at the front portion such that each of the first pair of leg elastics is positioned adjacent to one of the pair of leg openings. A second pair of leg elastics is secured between the outer cover and the inner liner at the back portion such that each of the second pair of leg elastics is positioned adjacent to one of the pair of leg openings. A third pair of leg elastics is secured between the outer cover and the inner liner such that each of the third pair of leg elastics is positioned adjacent to one of the pair of leg openings intermediate one of the first and second pairs of leg elastics. Each of the third pair of leg elastics is separated from one of the first pair of leg elastics by a first gap and from one of the second pair of leg elastics by a second gap. The first, second and third pairs of leg elastics allow gathers to form about each of the leg openings to prevent leakage of body fluid from the underpants. The underpants also contain waist elastic attached between the outer cover and the inner liner at the front and back portions. The waist elastics allow gathers to form about the waist opening to prevent leakage of body fluid from the underpants. The general object of this invention is to provide disposable absorbent underpants for containing body fluid. A more specific object of this invention is to provide disposable absorbent underpants for containing at least 100 grams of urine.

Another object of this invention is to provide disposable absorbent underpants for an adult suffering from incontinence. A further object of this invention is to provide disposable absorbent underpants at a reasonable cost that can prevent leakage of body fluid.

Still another object of this invention is to provide disposable absorbent underpants that are easy to manufacture.

Still further, an object of this invention is to provide disposable absorbent underpants that are more comfortable to wear.

Other objects and advantages of the present invention will become more apparent to those skilled in the art in view of the following description and the accompanying drawings. Brief Description of the Drawings

Fig. 1 is a top view of disposable absorbent underpants having three cut-away sections showing an outer cover and an inner liner and having three discrete pairs of leg elastics surrounding each leg opening which are separated from one another by a gap.

Fig. 2 is a perspective view of the disposable absorbent underpants when the front and back portions are joined together.

Fig. 3 is a cross-sectional view taken along line 3 — 3 of Fig. 1 showing the absorbent pad secured to the crotch portion of the inner liner.

Fig. 4 is a cross-sectional view taken along line 4 — 4 of Fig. 1 showing one of the first pair of leg elastics sandwiched between the outer cover and the inner liner.

Detailed Description of the Preferred Embodiments

Referring to Fig. 1 , disposable absorbent underpants 10 are shown in a flat configuration before being formed into a tubular product. The tubular product is depicted in Fig. 2. The underpantsl O is capable of absorbing and containing body fluid, especially urine. The underpants 10 have a longitudinal centerline X — X. The underpants 10 are manufacture and sold as a complete garment and are designed to be pulled up about the torso of an adult who is suffering from incontinence. However, the underpants 10 could be dimensioned to be a diaper designed to be worn by an infant or be a training pant designed to be worn by a toddler. Preferably, the underpantslO is an adult incontinent article that can be used day or night to absorb and contain urine. The disposable underpants 10 is constructed of an outer cover 12 having a front portion 14 and a back portion 16 joined together by a crotch portion 18. The outer cover 12 is located away from the body of the wearer in use. The outer cover 12 can be a single piece of material as shown or it can be made up of two or more separate pieces of material that are joined together. The outer cover 12 should be formed from a soft and flexible material and it can be either liquid-permeable or liquid impermeable. Preferably, the outer cover 12 is liquid impermeable. A suitable material for the outer cover 12 can be made from natural or synthetic fibers and/or films. Examples of natural fibers include cellulose wood fibers and cotton fibers. Examples of synthetic fibers include rayon fibers, polyester fibers, and polypropylene fibers. When a film is utilized, a thermoplastic film formed from a polyolefin, such as polypropylene or polyethylene works well. A combination of natural and synthetic materials can also be used to construct the outer cover 12. The outer cover 12 can also be formed from a woven or a non-woven web or sheet such as a spunbond, a meltblown or a bonded-carded web.

The disposable underpants 10 also contain an inner liner 20. The inner liner 20 is located toward the body of the wearer in use. The inner liner 20 has a front portion 22 and a back portion 24 joined together by a crotch portion 26. The inner liner 20 can be a single piece of material as shown or it can be made up of two or more separate pieces of material that are joined together. The inner liner 20 should be formed from a soft and flexible material and it can be either liquid-permeable or liquid impermeable. Preferably, the inner liner 20 is liquid permeable. The inner liner 20 can be attached or secured to the outer cover 12 by an adhesive, by sewing, by a pressure bond, by a thermal bond, by a pressure and thermal bond, or by another means known to those skilled in the art. The front portion 22 of the inner liner 20 is positioned above or over the front portion 14 of the outer cover 12 while the back portion 24 of the inner liner 20 is positioned above or over the back portion 16 of the outer cover 12. Likewise, the crotch portion 26 of the inner liner 20 is positioned above or over the crotch portion 18 of the outer cover 12. The combination of the two front portions 14 and 22 create a front waist portion 28 having distally spaced edges 30 and 32. The combination of the back portions 16 and 24 create a back waist portion 34 having distally spaced edges 36 and 38. The edges 30 and 32 of the front waist portion 28 are connected or sealed to the edges, 36 and 38 respectively, of the back waist portion 34 to form a tubular configuration 40 adaptable to fit around the torso of a person. The front and back waist portions, 28 and 34 respectively, are secured together to form a pair of side seams or seals 42 and 44. The side seams 42 and 44 may have a lap seal (not shown) or a T-seal that points inward toward the body or away from the body (not shown). The side seams 42 and 44 can be formed using an ultrasonic bond, by using an adhesive, by using a pressure bond, by using a thermal bond, by using a combination of heat and pressure or by using another means known to those skilled in the art. The tubular configuration 40 has a waist opening 46 and a pair of leg opening 48 and 50. The underpants 10 is designed to fit snugly around the torso of an adult suffering from incontinence and is designed to contain body fluid, especially urine, discharged by the wearer.

Referring to Figs. 1-3, an absorbent pad 52 is shown being secured to the crotch portion 26 by an adhesive 54, see Fig. 3. The absorbent pad 52 includes a liquid-permeable cover 56, a liquid impermeable baffle 58 and an absorbent layer 60 positioned therebetween. The liquid-permeable cover 56 and the liquid impermeable baffle 58 are joined or secured together about their peripheries by a construction adhesive 62. The absorbent layer 60 has a length L,, see Fig. 1 , and a width W-,, see Fig. 3, which are less than the length L₂ and the width W₂ of the absorbent pad 52. This means that the liquid-permeable cover 56 and the liquid impermeable baffle 58 are larger in size than the absorbent layer 60 and both extend beyond the outer periphery of the absorbent layer 60. This is important because by forming the absorbent layer 60 such that it has a smaller overall size, any body fluid received by the absorbent layer 60 will not be able to flow or wick outward to the outer edges of the absorbent pad 52. This feature will minimize and hopefully prevent the chance of fluid leakage from occurring. The absorbent layer 60 should have a width W-, that is at least about 0.125 inches (about 3.2 mm) less than the width W₂ of the absorbent pad 52. Preferably, the absorbent layer 60 will have a width W-i that is from between about 0.25 inches (about 6.4 mm) to about 1 inch (about 25.4 mm) less than the width W₂ of the absorbent pad 52. More preferably, the absorbent layer 60 will have a width Wi that is from between about 0.375 inches (about 9.5 mm) to about 0.75 inches (about 19 mm) less than the width W₂ of the absorbent pad 52. Referring to Fig. 3, one will notice that the crotch portion 26 of the inner liner 20 has a width W₃ and the width W₂ of the absorbent pad 52 is less than the width W₃ of the crotch portion 26. The absorbent pad 52 should have a width W₂ that is at least about 0.125 inches (about 3.2 mm) less than the width W₃ of the crotch portion 26. Preferably, the width W₂ of the absorbent pad 52 is from between about 0.25 inches (about 6.4 mm) to about 3 inches (about 76 mm) less than the width W₃ of the crotch portion 26. More preferably, the absorbent pad 52 will have a width W₂ that is from between about 0.375 inches (about 9.5 mm) to about 2 inches (about 51 mm) less than the width W₃ of the crotch portion 26. The reason for this size difference is that the underpants 10 is primarily designed to absorb urine and it is desirable to confine the urine to the absorbent layer 60. The absorbent layer 60 has a width W-i that is less than the width W₂ of the absorbent pad 52 and, in turn, the absorbent pad 52 has a width W₂ that is less than the width W₃ of the crotch portion 26. This size difference assures that if any urine wicks to the longitudinal side edges of the absorbent layer 60 that it will still be spaced apart from the longitudinal side edges of the absorbent pad 52. In turn, the urine will be further away from the longitudinal side edges of the crotch portion 26 and therefore will not leak onto the wearer's clothing or skin.

The liquid-permeable cover 56 can be formed from a liquid-permeable material so as to allow body fluid which strikes the absorbent pad 52 to pass down into the absorbent layer 60. The liquid-permeable cover 56 can be formed from a non-woven web, a spunbond, a meltblown or a bonded-carded web composed of synthetic polymer filaments or fibers. Examples of synthetic materials include polypropylene, polyethylene, polyesters and the like. The liquid-permeable cover 56 can also be formed from a perforated thermoplastic film. Other materials, which can also be utilized to form the cover 56, include rayon and cotton. The liquid-permeable cover 56 can be treated with a surfactant to aid in transfer of the body fluid into the absorbent layer 60, if desired. The liquid impermeable baffle 58 can be formed from a liquid impermeable material so as to prevent body fluid that contacts it from passing therethrough. The liquid impermeable baffle 58 can be formed from a thin sheet of thermoplastic material such as polyethylene, polypropylene, polyvinyl chloride and the like. Alternatively, the liquid impermeable baffle 58 can be a non-woven, fibrous web that has been constructed to have low liquid permeability. The liquid impermeable baffle 58 can also be constructed from a foam material. In some instances, it may be advantageous to form the liquid impermeable baffle 58 from a material that will allow vapor to pass through but which will prevent body fluid from passing through.

The absorbent layer 60 that is retained between the liquid-permeable cover 56 and the liquid impermeable baffle 58 should be primarily designed to absorb urine. However, it could be constructed to absorb other body fluids, such as menses, blood, perspiration, as well as other body excrements. The absorbent layer 60 can be formed from various natural and/or synthetic materials, such as cellulose fibers, wood pulp fibers, regenerated cellulose or cotton fibers, meltblown fibers, a blend of pulp and other fibers, or a combination of various fibers. A suitable material is "coform" which is a mixture of cellulose fibers and synthetic polymer fibers. Coform is manufactured by Kimberly-Clark Corporation having an office at 401 North Lake Street Neenah, Wisconsin 54956.

The absorbent layer 60 can also include superabsorbent materials, commonly referred to as "superabsorbents", to increase its absorbency and ability to retain body fluids under pressure loads. The superabsorbents can be present in particle form, as flakes or have some other structural shape. The superabsorbents can be secured to the absorbent fibers by an adhesive or they can be loosely positioned between the absorbent fibers. Suitable superabsorbents are commercially available from Dow Chemical Company, Hoechst Celanese Corporation and Allied Colloids, Inc. The absorbent layer 60 may be wrapped in tissue or some similar kind of acquisition and/or distribution layer to assist in maintaining the integrity of the absorbent fibers and the superabsorbents.

It should be noted that the absorbent pad 52 should be designed to absorb at least about 100 grams of body fluid, such as urine. Preferably, the absorbent pad 52 should be design to absorb from between about 100 grams to about 1500 grams of body fluid. More preferably, the absorbent pad 52 should be design to absorb about 500 grams of body fluid. Even more preferably, the absorbent pad 52 should be design to absorb about 1 ,000 grams of body fluid. Most preferably, the absorbent pad 52 should be design to absorb about 1 ,500 grams of body fluid.

In order to measure the absorbency of the absorbent pad 46, one should use a "Saturated Retention Capacity Test." The "Saturated Retention Capacity" of the absorbent pad 46 can be measured using the following procedure. First, the absorbent pad 46 is measured to make sure it has a moisture content of less than about 7 weight percent. The moisture content value can be obtained by following the ASTM D-2495 (7.01) Standard Test Method for Moisture Content in Cotton by Oven-Drying. The absorbent pad 46 is then weighed to obtain its "dry weight." The absorbent pad 46 is then submerged in an excess quantity of synthetic urine at room temperature (about 23 degrees Celsius). The composition of the synthetic urine comprises 0.31 grams of monobasic calcium phosphate monohydrate (CaH4(PO4)2H20), 0.68 grams of monobasic potassium phosphate (KH2PO4), 0.48 grams of magnesium sulphate heptahydrate (MgSO4 7H20), 1.33 grams of potassium sulphate (K2SO4), 1.24 grams of tribasic sodium phosphate dodecahydrate (Na3PO4 12H2O), 4.4 grams of sodium chloride (NaCI), 3.16 grams of potassium chloride (KCI), 8.56 grams of urea (CO(NH2)2), 0.1 grams of Pluronic 10R8 surfactant (a non-ionic surfactant commercially available from BASF-Wyandotte Corporation), 1 gram of methyl paraben and 1 gram of Germall 115 preservative (commercially available from Santell Chemical Company, Chicago, III.) per liter using distilled water as the solvent. The above- identified components are added to 900 milliliters of distilled water in the order given and each dissolved before the next component is added. The solution is finally diluted to one liter.

The absorbent pad 46 is allowed to remain submerged in the synthetic urine for 20 minutes. After 20 minutes, the absorbent pad 46 is removed from the synthetic urine and placed on a TEFLON® coated fiberglass screen. TEFLON® is a registered trademark of E. I. DuPont de Nemours & Company having an office at 1002 Market Street, Wilmington, Delaware 19801. The screen has a plurality of openings of about 0.25 inches (about 6.4 mm) in width. Such a screen is commercially available from Taconic Plastics Inc., having an office in Petersburg, N.Y. The screen is positioned on a vacuum box and the absorbent pad 46 is positioned in direct contact with the upper surface of the screen. The absorbent pad 46 and screen are covered with a flexible rubber dam material. A vacuum of 3.5 kilopascals (about 0.5 pounds per square inch) is drawn into the vacuum box for a period of 5 minutes. The flexible rubber dam material is removed and the absorbent pad 46 is withdrawn and weighed to obtain it's "wet weight." The amount of fluid retained by the absorbent pad 46 is determined by subtracting its dry weight from its wet weight. The "Saturated Retention Capacity" of the absorbent pad 46 is equal to the fluid, measured in grams, which is retained by the absorbent pad 46.

A surge layer 64 can optionally be positioned above the absorbent layer 60 such that it is in direct contact with the liquid-permeable cover 56. The purpose of the surge layer 64 is to quickly take up body fluid that contacts the cover 56 and direct this body fluid downward toward the absorbent layer 60. In addition, the surge layer 64 can direct the body fluid outward in the transverse and longitudinal directions so that it is capable of contacting a greater surface area of the absorbent layer 60. This ability to quickly move the body fluid in the x, y and z directions diffuses surges of body fluid which insult the absorbent pad 52. The surge layer 64 is also commonly referred to as an acquisition/distribution layer. The surge layer 64 can be formed from a through-air bonded carded web composed of a blend of 40 percent 6 denier polyester fibers, commercially available from Hoechst Celanese corporation, and 60 percent 3 denier polypropylene/polyethylene sheath core bicomponent fibers, commercially available from Chisso Corporation. The surge layer 64 can have an overall basis weight ranging from about 50 grams per square meter (gsm) to about 120 gsm. In Fig. 1 , the surge layer 64 is depicted as having a rectangular configuration but it could be formed into other shapes as well, including an hourglass shape, an oval shape, etc.

Referring to Figs. 1 and 4, the underpants 10 includes a first pair of leg elastics 66 secured between the outer cover 12 and the inner liner 20. The first pair of leg elastics 66 is present on the right and left sides of the front waist portion 28. Each of the first pair of leg elastics 66 is positioned adjacent to one of the pair of leg openings, 48 and 50 respectively. The first pair of leg elastics 66 is depicted as being three strands of an elastic material although a fewer or a greater number of strands can be utilized if desired. It has been found that three strands provide adequate elastic strength to form gathers about each of the leg openings 48 and 50. The first pair of leg elastics 66 can be secured at intermittent sites to the outer cover 12 and to the inner liner 20 by an adhesive, by ultrasonic bonding, by heat and/or pressure bonds or by some other means known to those skilled in the art. Materials suitable for forming the first pair of leg elastics 66 include polyurethane, rubber, and other elastomeric materials. The first pair of leg elastics 66 can be in the form of long or short elastic strands, elastic tapes, ribbons, yarns, etc. The first pair of leg elastics 66 can have a cross-sectional configuration that is flat, square, rectangular, circular, oval or some other shape. A good material from which the first pair of leg elastics 66 can be formed is LYCRA®. LYCRA® is a registered trademark of the E. I. DuPont de Nemours & Company that has an office at 1002 Market Street, Wilmington, Delaware 19801. Each of the first pair of leg elastics 66 is positioned adjacent to a first pair of edges 68. Each of the first pair of edges 68 is substantially liner in configuration and each extends inward toward the crotch portion 26 from one of the two distally spaced edges 30 and 32. Preferably, at least about 70% of the length of each of the first pair of edges 68 are linear in configuration. Each of the first pair of edges 68 are aligned at an angle alpha ( ) to the longitudinal centerline X — X of the underpants 10. The angle alpha (a) can range from between about 62 degrees to about 99 degrees. Preferably, the angle alpha (a) can range from between about 74 degrees to about 91 degrees, and most preferably, the angle alpha (a) is at least about 85 degrees. The angling of the first pair of edges 68 relative to the longitudinal centerline X — X ensures a better contouring of the underpants 10 to the body and provides a comfortable fit with reduced bunching.

The first pair of leg elastics 66 is located along and is preferably aligned parallel to the first pair of edges 68. Each of the first pair of leg elastics 66 has a first end 70 located adjacent to or coterminous to one of the distal edges, 30 and 32 respectively. Preferably, each of the first ends 70 is spaced slightly inward from one of the two distal edges 30 and 32. The first pair of leg elastics 66 should extend toward the absorbent pad 52 but should stop short thereof. Each of the first pair of leg elastics 66 terminates at a second end 72. Each end 72 is located away from the outer periphery of the absorbent pad 52. The exact distance of the second ends 72 from the outer periphery of the absorbent pad 52 can vary from between about 3 millimeter to about 75 millimeters, and preferably, the distance is less than about 25 millimeters. By the ends 64 and 66, of the first pair of elastics 60, it is meant the ends of the gathered material where the effectiveness of the elastic ends. This can differ from the physical ends of the elastic material which is normally longer and represents the actual ends of the individual elastic filaments or strands. The underpants 10 also include a second pair of leg elastics 74 secured between the outer cover 12 and the inner liner 20. The second pair of leg elastics 74 is present on the right and left sides of the back waist portions 34. Each of the second pair of leg elastics 74 is positioned adjacent to one of the pair of leg openings, 48 and 50 respectively. The second pair of leg elastics 74 is depicted as being three strands of an elastic material although a fewer or a greater number of strands can be utilized if desired. It has been found that three strands provide adequate elastic strength to form gathers about each of the leg openings 48 and 50. The second pair of leg elastics 74 can be secured at intermittent sites to the outer cover 12 and to the inner liner 20 by an adhesive, by ultrasonic bonding, by heat and/or pressure bonds or by some other means known to those skilled in the art. Materials suitable for forming the second pair of elastics 74 include those described above with reference to the first pair of leg elastics 66. Like the first pair of elastics 66, the second pair of leg elastics 74 can be in the form of long or short elastic strands, elastic tapes, ribbons, yarns, etc. The second pair of leg elastics 74 can have a cross-sectional configuration that is flat, square, rectangular, circular, oval or some other shape. Each of the second pair of leg elastics 74 is positioned adjacent to a second pair of edges 76. Each of the second pair of edges 76 is substantially liner in configuration and extends inward toward the crotch portion 26 from the two distally spaced edges 36 and 38. Preferably, at least about 70% of the length of each of the second pair of edges 76 are linear in configuration. Each of the second pair of edges 76 are aligned at an angle beta ( ?) to the longitudinal centerline X — X of the underpants 10. The angle beta (/?) can range from between about 45 degrees to about 89 degrees. Preferably, the angle beta (β) can range from between about 55 degrees to about 87 degrees, and most preferably, the angle beta (β) is from between about 61 degrees to about 76 degrees. The angling of the second pair of edges 76 relative to the longitudinal centerline X — X ensures a better contouring of the underpants 10 to the body and provides a comfortable fit with reduced bunching.

The second pair of leg elastics 74 is located along and preferably aligned parallel to the second pair of edges 76. Each of the second pair of leg elastics 74 has a first end 78 located adjacent to or coterminous to one of the distal edges, 36 and 38 respectively. Preferably, each of the first ends 78 is spaced slightly inward from one of the two edges 36 and 38. The second pair of leg elastics 74 should extend toward the absorbent pad 52 but the gathered end of the elastic material should stop short thereof. Each of the second pair of leg elastics 74 terminates at a second end 80. Each second end 80 is located away from the outer periphery of the absorbent pad 52. The exact distance can vary from between about 3 millimeter to about 75 millimeters, and preferably, the distance is less than about 25 millimeters. As stated above with reference to the first pair of leg elastics 66, the first and second ends, 78 and 80 respectively, of the second pair of leg elastics 74 refer to the gathered end of the elastic material and not to the actual length of the individual elastic filaments or strands. The disposable absorbent underpants 10 further includes a third pair of leg elastics

82 secured between the outer cover 12 and the inner liner 20. The third pair of leg elastics 82 is present on the right and left sides of the crotch portion 26. Each of the third pair of leg elastics 82 is positioned adjacent to one of the pair of leg openings, 48 and 50 respectively. The third pair of leg elastics 82 is depicted as being three strands of an elastic material although a fewer or a greater number of strands can be utilized if desired. It has been found that three strands provide adequate elastic strength to form gathers about each of the leg openings 48 and 50. The third pair of leg elastics 82 can be secured at intermittent sites to outer cover 12 and to the inner liner 20 by an adhesive, by ultrasonic bonding, by heat and/or pressure bonds or by some other means known to those skilled in the art. Materials suitable for forming the third pair of elastics 82 include those described above with reference to the first and second pairs of leg elastics, 66 and 74 respectively. Like the first and second pairs of leg elastics, 66 and 74 respectively, the third pair of leg elastics 82 can be in the form of long or short elastic strands, elastic tapes, ribbons, yarns, etc. The third pair of leg elastics 82 can have a cross-sectional configuration that is flat, square, rectangular, circular, oval or some other shape. Each of the third pair of leg elastics 82 is positioned adjacent to a third pair of edges 84. Each of the third pair of edges 84 has an arcuate or curved configuration and extends adjacent to the outside periphery of the crotch portion 26. Preferably, each of the third pair of leg elastics 82 is aligned parallel to one of the third pair of edges 84. Each of the third pair of leg elastics 82 can be secured within about 0.5 inches (about 13 mm) from a respective side edge 84. Preferably, each of the third pair of leg elastics 82 can be secured within about 0.375 inches (about 9.5 mm) from a respective side edge 84.

Each of the third pair of leg elastics 82 is positioned intermediate one of the first and second pairs of leg elastics 66 and 74 respectively. Each of the third pair of leg elastics 82 has a first end 86 and a second end 88. As stated above with reference to the first and second pairs of leg elastics 66 and 74, the first and second ends, 86 and 88 respectively, of the third pair of leg elastics 82 refer to the gathered end of the elastic material and not to the actual length of the individual elastic filaments or strands.

The first end 86 of each of the third pair of leg elastics 82 is separated from the second end 72 of the first pair of leg elastics 66 by a first pair of gaps 90. The dimension of each of the first pair of gaps 90 is denoted as "D and D₁ can be at least about

0.125 inches (about 3.2 mm) in length. Preferably, the dimension D-, of each of the first pair of gaps 90 is from between about 0.25 inches (about 6.4 mm) to about 9 inches (about 229 mm). More preferably, the dimension D-i of each of the first pair of gaps 90 is from between about 0.375 inches (about 9.5 mm) to about 5 inches (about 127 mm). Most preferably, the dimension D-] of each of the first pair of gaps 90 is from between about 0.5 inches (about 13 mm) to about 2 inches (about 51 mm). The dimension D-i is measured when the underpants 10 are in a flat, extended orientation similar to that depicted in Fig. 1. To measure the distance of the gap D^ one should mark the gathered ends 72 and 86 of the first and third pairs of leg elastics 66 and 82 in a relaxed state. The underpants 10 are then extended until all the material is flat, as depicted in Figs. 1 and 5. In this configuration, the two pair of leg elastics 66 and 82 will be stretched out and the actual distance between the marks will represent the dimension of the gap D^

Likewise, the second end 88 of each of the third pair of leg elastics 82 is separated from the second end 80 of the second pair of leg elastics 74 by a distance "D₂" by a second pair of gaps 92. The dimension of each of the second pair of gaps 92 is denoted as "D₂" and D₂ can be at least about 0.125 inches (about 3.2 mm) in length. Preferably, the dimension D₂ of each of the second pair of gaps 92 is from between about 0.25 inches (about 6.4 mm) to about 9 inches (about 229 mm). More preferably, the dimension D₂ of each of the second pair of gaps 92 is from between about 0.375 inches (about 9.5 mm) to about 5 inches (about 127 mm). Most preferably, the dimension D₂ of each of the second pair of gaps 92 is from between about 0.5 inches (about 13 mm) to about 2 inches (about 51 mm). The dimension D₂ is measured when the underpants 10 are in a flat, extended orientation similar to that depicted in Fig. 1. To measure the distance of the gap D₂, one should mark the gathered ends 80 and 88 of the second and third pairs of leg elastics 74 and 82 in a relaxed state. The underpants 10 are then extended until all the material is flat, as depicted in Figs. 1 and 5. In this configuration, the two pair of leg elastics 74 and 82 will be stretched out and the actual distance between the marks will represent the dimension of the gap D₂.

It should be noted that two pairs of gaps 90 and 92 have been described. However, if one desired to use only one of the two pairs of gaps, 90 and 92, that this can be done. One could also use additional gaps, if desired, without destroying the function of this invention. Preferably, the two pairs of gaps 90 and 92 will be utilized.

The first and second pairs of gaps, 90 and 92 respectively, ensures that the first, second and third pairs of leg elastics, 66, 74 and 82 respectively, will cooperate together to form gathers 94 and 96 around the first and second leg openings, 48 and 50 respectively. The gathers 94 and 96, best depicted in Fig. 2, form a snug fit around the entire circumference of each leg opening 48 and 50. The two pairs of gaps 90 and 92 will prevent the adjacent leg elastics 66, 74 and 82 from overlapping one another and forming bumps and/or humps around the leg openings 48 and 50. By eliminating such bumps and humps, one can prevent the leakage of body fluid through the leg openings 48 and 50. It is very important that fluid leakage from around the leg openings 48 and 50 be eliminated because if such leakage occurs, the usefulness of the underpants 10 is compromised.

Even though the two pairs of gaps 90 and 92 are present in the stretched out, flat orientation shown in Figs. 1 and 5, the contraction force of the first, second and third pairs of leg elastics 60, 68 and 76 will cause the gathers 88 and 90 to form. The force of the elastics 60, 68 and 76 adjacent to the gaps 84 and 86 will cause the material forming the outer cover 12 and the inner liner 20 to fit snug against the thighs of the wearer during use. No fluid channels will occur at the locations of the first and second pairs of gaps 84 and 86. This will assure that no body fluid will be able to leak out through these locations (U_! and D₂) during normal use. Referring again to Figs. 1 and 2, the disposable absorbent underpants 10 further has waist elastic 98 attached to the front waist portion 28 and waist elastic 100 attached to the back waist portion 34. The waist elastics 98 and 100 can include threads, strands, ribbons, bands, film, elastic non-wovens or composites. The threads, strands, ribbons, etc. may be a multitude of singular members or they may be applied as a composite. The number of elastic members can range from 1 to over a 100. Preferably, the number of elastic members will range from between about 10 to about 40, and most preferably, from about 15 to about 35. There can be an equal number or a different number of waist elastics 98 in the front waist portion 28 versus the number of waist elastics 100 in the back waist portion 34. The waist elastics 98 and 100 can be individual threads that are spaced apart from one another from between about 0.063 inches (about 1.6 mm) to about 2.0 inches (about 51 mm). Preferably, the waist elastics 98 and 100 can be individual threads that are spaced apart from one another by about 0.25 inches (about 6.4 mm). While the appearance of the underpants 10 may be enhanced by the close even spacing of the waist elastics 98 and 100, the exact distance between adjacent waist elastics 98 or 100 can vary.

The waist elastics 98 and 100 may be made from any suitable elastomeric material. One suitable material is LYCRA®. LYCRA® is a registered trademark of the E. I. DuPont de Nemours & Company that has an office at 1002 Market Street, Wilmington, Delaware 19801. Suitable waist elastics 98 and 100 include threads having a decitex (grams/10,000 meters) of from between about 100 to about 1 ,200, preferably, from between about 470 to about 940, and most preferably, from between about 620 to about 740. The waist elastics 98 and 100 can be secured to the outer cover 12 and to the inner liner 20 by a hot or cold melt adhesive applied in a variety of spray patterns. One spray pattern that has been used with good success is a swirl pattern. A preferred adhesive is a hot melt adhesive sold as Findley H2096 by ATO Findley Adhesives having an office in Milwaukee, Wisconsin.

While the invention has been described in conjunction with a specific embodiment, it is to be understood that many alternatives, modifications and variations will be apparent to those skilled in the art in light of the aforegoing description. Accordingly, this invention is intended to embrace all such alternatives, modifications and variations that fall within the spirit and scope of the appended claims.

Claims (19)

We claim:

1. A disposable absorbent underpants for containing body fluid comprising: a) an outer cover having a front portion and a back portion joined together by a crotch portion; b) an inner liner attached to said outer cover, said inner liner having at a front portion and a back portion joined together by a crotch portion, said front and back portions of said outer cover and said inner liner being connected together to form a waist opening and a pair of leg openings; c) an absorbent pad secured to said crotch portion, said absorbent pad including a liquid-permeable cover, a liquid impermeable baffle and an absorbent layer positioned therebetween; d) a first pair of leg elastics secured between said outer cover and said inner liner at said front portion, each of said first pair of leg elastics being positioned adjacent to one of said pair of leg openings; e) a second pair of leg elastics secured between said outer cover and said inner liner at said back portion, each of said second pair of leg elastics being positioned adjacent to one of said pair of leg openings; f) a third pair of leg elastics secured between said outer cover and said inner liner at said crotch portion, each of said third pair of leg elastics being positioned adjacent to one of said leg openings intermediate one of said first and second pairs of leg elastics, each of said third pair of leg elastics being separated from said first pair of leg elastics by a first gap and being separated from second pair of leg elastics by a second gap, said first, second and third pairs of leg elastics allowing gathers to form about each of said leg openings to prevent leakage of body fluid from said underpants; and g) waist elastic attached between said outer cover and said inner liner at said front and back portions, said waist elastics allowing gathers to form about said waist opening to prevent leakage of body fluid from said underpants.

2. The disposable absorbent underpants of claim 1 wherein said first gap has a dimension of at least about 0.125 inches.

3. The disposable absorbent underpants of claim 1 wherein said second gap has a dimension of at least about 0.125 inches.

4. The disposable absorbent underpants of claim 1 wherein said first gap has a dimension of from between about 0.25 inches to about 9 inches.

5. The disposable absorbent underpants of claim 4 wherein said first gap has a dimension of from between about 0.375 inches to about 5 inches.

6. The disposable absorbent underpants of claim 1 wherein said second gap has a dimension of from between about 0.25 inches to about 9 inches.

7. The disposable absorbent underpants of claim 6 wherein said second gap has a dimension of from between about 0.375 inches to about 5 inches.

8. The disposable absorbent underpants of claim 1 wherein said absorbent pad has a capacity for absorbing about 100 grams of body fluid.

9. The disposable absorbent underpants of claim 8 wherein said absorbent pad has a capacity for absorbing about 500 grams of body fluid.

10. A disposable absorbent underpants for containing body fluid comprising: a) an outer cover having a front portion and a back portion joined together by a crotch portion; b) an inner liner having a front portion and a back portion joined together by a crotch portion, said front and back portions of said inner liner being attached to said front and back portions of said outer cover to form a waist opening and a pair of leg openings; c) an absorbent pad secured to said crotch portion of said inner liner and having a capacity for absorbing at least about 100 grams of body fluid, said absorbent pad including a liquid-permeable cover, a liquid impermeable baffle and an absorbent layer positioned therebetween; d) a first pair of leg elastics secured between said outer cover and said inner liner at said front portion, each of said first pair of leg elastics being positioned adjacent to one of said pair of leg openings; e) a second pair of leg elastics secured between said outer cover and said inner liner at said back portion, each of said second pair of leg elastics being positioned adjacent to one of said pair of leg openings; f) a third pair of leg elastics secured between said outer cover and said inner liner, each of said third pair of leg elastics being positioned adjacent to one of said leg openings intermediate one of said first and second pairs of leg elastics, each of said third pair of leg elastics being separated from said first pair of leg elastics by a first gap and being separated from second pair of leg elastics by a second gap, said first, second and third pairs of leg elastics allowing gathers to form about each of said leg openings to prevent leakage of body fluid from said underpants; and g) waist elastic attached between said outer cover and said inner liner at said front and back portions, said waist elastics allowing gathers to form about said waist opening to prevent leakage of body fluid from said underpants.

11. The disposable absorbent underpants of claim 10 wherein said first gap has a dimension of at least about 0.125 inches.

12. The disposable absorbent underpants of claim 10 wherein said second gap has a dimension of at least about 0.125 inches.

13. The disposable absorbent underpants of claim 10 wherein both of said first and second gaps have a dimension of from between about 0.25 inches to about

9 inches.

14. The disposable absorbent underpants of claim 10 wherein said absorbent pad has a capacity for absorbing about 500 grams of body fluid.

15. A disposable absorbent underpants for containing body fluid comprising: a) an outer cover having a front portion and a back portion joined together by a crotch portion; b) an inner liner having a front portion and a back portion joined together by a crotch portion, said front and back portions of said inner liner being attached to said front and back portions of said outer cover to form a waist opening and a pair of leg openings; c) an absorbent pad secured to said crotch portion of said inner liner and having a capacity for absorbing at least about 100 grams of body fluid, said absorbent pad including a liquid-permeable cover, a liquid impermeable baffle, and a surge layer and an absorbent layer positioned between said liquid-permeable cover and said liquid impermeable baffle, said liquid impermeable baffle being secured to said crotch portion by an adhesive; d) a first pair of leg elastics secured between said outer cover and said inner liner at said front portion, each of said first pair of leg elastics being positioned adjacent to one of said pair of leg openings; e) a second pair of leg elastics secured between said outer cover and said inner liner at said back portion, each of said second pair of leg elastics being positioned adjacent to one of said pair of leg openings; f) a third pair of leg elastics secured between said outer cover and said inner liner, each of said third pair of leg elastics being positioned adjacent to one of said leg openings intermediate one of said first and second pairs of leg elastics, each of said third pair of leg elastics being separated from one of said first pair of leg elastics by a first gap and being separated from one of said second pair of leg elastics by a second gap, said first, second and third pairs of leg elastics allowing gathers to form about each of said leg openings to prevent leakage of body fluid from said underpants; and g) waist elastic attached between said outer cover and said inner liner at said front and back portions, said waist elastics allowing gathers to form about said waist opening to prevent leakage of body fluid from said underpants.

16. The disposable absorbent underpants of claim 15 wherein said absorbent pad has a capacity for absorbing about 500 grams of body fluid.

17. The disposable absorbent underpants of claim 16 wherein said absorbent pad has a capacity for absorbing about 1 ,000 grams of body fluid.

18. The disposable absorbent underpants of claim 15 wherein said third pair of leg elastics are secured to said crotch portion between said outer cover and said inner liner by an adhesive.

19. The disposable absorbent underpants of claim 15 wherein said crotch portion has a pair of side edges and each of said third pair of leg elastics are secured within 0.5 inches from one of said pair of side edges.

0. The disposable absorbent underpants of claim 15 wherein said crotch portion has a pair of side edges and each of said third pair of leg elastics are secured within 0.375 inches from one of said pair of side edges.