Disposable absorbent article with selectively expandable components

Other references

1. teach adding a spacer to the disposable absorbent article. Such spacers can suffer from the drawback that they increase the thickness and bulkiness of the disposable absorbent article, and thereby increase shipping and storage costs. Such spacers may al
2. Still other references disclose absorbent articles having inflatable structures. French Patent Application 2,561,078 published Sep. 20, 1985 in the name of Lefebvre discloses a diaper having a structure which is inflatable by mouth. Such inflation can b
3. U.S. Pat. Nos. 3,881,491 and 3,921,232 issued to Whyte on May 6, 1975 and Nov. 25, 1975, respectively, disclose disposable absorbent articles having self inflating structures. The self inflating structures include a wall of semipermeable material and
4. Accordingly, it would be advantageous to provide an absorbent article having a component that is expandable. It would also be desirable to provide an absorbent article having a component that is inflatable at the point of use of the absorbent article by
5. SUMMARY OF THE INVENTION
6. In order to solve the problems of the prior art, the present invention is directed to a disposable absorbent article having a topsheet, a backsheet, an absorbent core disposed intermediate the topsheet and backsheet, and an expandable component. The expa
7. BRIEF DESCRIPTION OF THE DRAWINGS
8. While the Specification concludes with claims particularly pointing out and distinctly claiming the present invention, the same will be better understood from the following description taken in conjunction with the associated drawings in which like refere
9. FIG. 1 is a top plan view of a disposable diaper embodiment of the present invention, the diaper shown partially cut-away and incorporating an inflatable keyhole-shaped spacer shown in phantom.
10. FIG. 2 is a top plan view of a disposable diaper embodiment of the present invention, the diaper shown partially cut-away and incorporating an inflatable U-shaped spacer and an inflatable barrier leg cuff component, the spacer and leg cuff component shown
11. FIG. 3 is a cross-sectional view taken along line 3--3 of FIG. 1, with the spacer joined to an upper layer of the absorbent core.
12. FIG. 4 is a cross-sectional view taken along line 3--3 of FIG. 1, with the spacer joined to the backsheet.
13. FIG. 5 is a top plan view of a keyhole shaped inflatable spacer shown partially cut-away to show a first gas evolving material and a second activating liquid enclosed in a breakable packet.
14. FIG. 5A is a cross-sectional view of a gas permeable envelope containing both the gas evolving material and the packet containing the activating material.
15. FIG. 5B is a cross-sectional view of an alternative embodiment of the present invention shown in FIG. 5A.
16. FIG. 6 is a cross-sectional view taken along line 6--6 of FIG. 5 showing the spacer having a first uninflated thickness.
17. FIG. 7 is a cross-sectional view taken along line 6--6 of FIG. 5 showing the spacer having a second inflated thickness, wherein one of the spacer chamber walls is substantially more extensible than the other or is preformed.
18. FIG. 8 is a cross-sectional view taken along line 6--6 of FIG. 5, showing the spacer having a second inflated thickness, wherein both spacer chamber walls deform upon inflation to form a generally oval shaped inflated spacer cross-section.
19. FIG. 9 is a cross-sectional view taken along line 9--9 of FIG. 2 showing an inflated component,comprising a portion of a barrier leg cuff.
20. DETAILED DESCRIPTION OF THE INVENTION
21. As used herein, the term "absorbent article" refers to devices which absorb and contain body exudates, and, more specifically, refers to devices which are placed against or in proximity to the body of the wearer to absorb and contain the various exudates
22. FIG. 1 is a plan view of the diaper 20 of the present invention in its flat-out, uncontracted state (i.e., with elastic induced contraction pulled out) with portions of the structure being cut-away to more clearly show the construction of the diaper 20 an
23. The front waist region 22 and the rear waist region 24 are those portions of the diaper 20 which, when worn, encircle the waist of the wearer and are generally the highest elevation of the diaper 20 when the wearer is in the standing position. The crotch
24. As shown in FIG. 1, the diaper 20 preferably comprises a topsheet 38, a backsheet 42 joined with the topsheet 38, and an absorbent core 44 positioned between the topsheet 38 and the backsheet 42. The absorbent core 44 can comprise an upper layer joined t
25. Referring to FIGS. 1, 3, 5, 6, and 7, the diaper 20 according to the present invention also comprises at least one expandable component 200 which is expandable from a first thickness T1 (FIG. 6) to a predetermined shape having a second thickness T2 (FIG.
26. The diaper 20 preferably also comprises a means or structure that the user can activate to expand the spacer 210 as desired. For example, in the embodiment shown in FIG. 5, the means for expanding the spacer 210 comprises a first material 300 disposed wi
27. Referring to FIG. 1, the diaper 20 preferably also includes a pair of tape tab fasteners 54 positioned in the rear waist region 24 for fastening the diaper 20 to the wearer. The diaper 20. can also have gasket cuffs 56, each comprising a side flap 58 an
28. The diaper 20 may also include a waist elastic feature, such as an elasticized waist band. U.S. Pat. No. 3,848,594 issued Nov. 19, 1974 to Buell and U.S. Reissue Pat. No. B1 4,662,875 reissued May 5, 1987 to Hirotsu et al. are incorporated herein by
29. FIG. 1 shows a preferred embodiment of the diaper 20 in which the topsheet 38 and the backsheet 42 have length and width dimensions generally larger than those of the absorbent core 44. The topsheet 38 and the backsheet 42 preferably extend beyond the ed
30. As used herein, the "longitudinal" dimension, direction, or axis of the diaper 20 is aligned front to back with respect to the wearer as the disposable absorbent article is worn. The "lateral" or "transverse" dimension, direction, or axis of the diaper 2
31. The embodiment described herein is exemplary of a product suitable for a wearer weighing about 7.3 kilograms to about 12.2 kilograms (16 to 27 pounds) and having ischia bones spaced about 3.0 centimeters to about 7.6 centimeters (1.2 to 3.0 inches) apart.
32. The spacer 210 is preferably inflatable from the first thickness T1 to the second, substantially greater thickness T2. By "substantially greater" it is meant that T2 is at least about 5 times, and preferably at least about 50 times as great as T1. The s
33. The spacer 210 illustrated in FIG. 1 and 5 has a generally "keyhole" shape comprising a closed figure. Alteratively, the spacer 210 can comprise a generally U-shaped figure opening rearward, as shown in FIG. 2, or any other suitable shape. In the altern
34. In one embodiment, the spacer 210 of FIG. 5 sized for the above mentioned wearers can have an overall longitudinal dimension 212 of about 8.9 to about 11.8 centimeters (3.5 to 4.6 inches) and a maximum transverse opening 213 of about 1.9 to 3.8 centimeter
35. The diaper 20 sized to fit the aforementioned range of wearers may be made having a topsheet 38 with a longitudinal dimension of about 43.8 centimeters (17.25 inches) and a backsheet 42 having a longitudinal dimension of about 46.4 centimeters (18.25 inch
36. The difference in dimensions between the topsheet 38 and the backsheet 42 foreshortens the topsheet 38 relative to the backsheet 42 creating the void space 211 therebetween, even with the absorbent core 44 disposed intermediate the topsheet 38 and the bac
37. As used herein, a "void space" is a cavity intermediate the topsheet 38 and the backsheet 42, which cavity is sized to accept fecal material. A void space 211 can be closed if the absorbent core 44 is compressed between the topsheet 38 and the backsheet
38. Examining the components of the diaper 20 in more detail, the topsheet 38 and backsheet 42 are generally coextensive and at least partially peripherally joined together. As used herein the term "joined" refers to the condition where a first member or com
39. The topsheet 38 and backsheet 42 may be joined by any means well known in the art, such as adhesive bonding, ultrasonic bonding or heat sealing. A particularly preferred method of joining the topsheet 38 and backsheet 42 is using hot-melt adhesive such a
40. As used herein, the term "absorbent core" refers to any component of the diaper 20 used for absorbing and retaining body exudates. The absorbent core 44 may have opposed major faces and may, if desired, be encased by one or more layers of tissue (not sho
41. The tissue layer, if present, improves the tensile strength of the absorbent core 44 and reduces its tendency to split or clump when wetted. The tissue layer may further improve transverse wicking of fluids and more evenly distribute absorbed liquids thr
42. A tissue layer having a basis weight of approximately 16 grams per square meter (10 pounds per 3,000 square feet) and an air permeability of approximately 30 cubic meters per minute per square meter (100 cubic feet per minute per square foot) and a differ
43. The absorbent core 44 may be made from a variety of commonly used natural or synthetic materials, including, but not limited to, comminuted wood pulp, typically referred to as airfelt. If desired, the absorbent core 44 may further contain particulate or
44. If desired, the lower layer 44L of the absorbent core 44 may have discrete storage and acquisition zones. The storage zone has a higher average density and higher average basis weight than the acquisition zone, so that the acquisition zone may effectivel
45. FIGS. 3 and 4 illustrate an upper layer 44U which is joined to the underside of the topsheet 38 and a lower layer 44L which is joined to the upper side of the backsheet 42. The absorbent core 44 has longitudinal and transverse dimensions generally less t
46. The upper and lower layers 44U and 44L of the absorbent core 44 may be adhesively joined to the topsheet 38 and backsheet 42, respectively, or joined thereto by any attachment means well known in the art.
47. Particularly preferred attachment means are adhesive spirals and longitudinal and transverse bands of adhesive. Particularly preferred types of adhesive are manufactured by Century Adhesives, Inc. of Columbus, Ohio as Century 5227, HL-1258 Adhesive sold
48. Preferably, the lower layer 44L of the absorbent core 44 extends the entire longitudinal dimension of the diaper 20 between the front waist region 22 and the rear waist region 24, but does not intrude into either the front waist region 22 or the rear wais
49. Preferably, the exposed faces of the upper layer 44U and the lower layer 44L (those faces not attached to the topsheet 38 or the backsheet 24 respectively) are well defined and do not allow a significant quantity of loose fibers to intrude into the void s
50. Referring back to FIG. 1, the "topsheet" refers to any liquid pervious facing of the diaper 20 which contacts the skin of the wearer while the diaper 20 is worn and prevents substantial contact of the absorbent core 44 with the skin of the wearer. The to
51. A suitable topsheet 44 may be manufactured from materials such as porous foams, apertured plastic films, natural fibers (e.g., wood fibers or cotton fibers), synthetic fibers (e.g., polyester or polypropylene fibers) or a combination of the foregoing. A
52. A particularly preferred topsheet 38 is carded and thermally bonded and has a basis weight of about 18 to about 25 grams per square meter. A suitable topsheet 38 is marketed by Veratec, Inc., Division of International Paper Company of Walpole, Mass. und
53. Alternatively, the topsheet 38 can comprise a formed film. The following patents are incorporate herein by reference for the purpose of describing suitable formed films: U.S. Pat. No. 3,929,135 issued to Thompson, Dec. 30, 1975; U.S. Pat. No. 4,324,
54. The topsheet 38 may include elastic elements or an elastic panel intermediate the lateral axis 34 and the rear waist region 24. Such an elastic panel maintains the topsheet 38 close to the wearer's skin, and helps to maintain registration of the aperture
55. Referring to FIGS. 1-2, the aperture 46 is preferably laterally centered on the longitudinal axis 36. The aperture 46 may be of any shape desired with a suitable shape being an oval having a longitudinal dimension of about 5.1 centimeters (2.0 inches) an
56. It is desirable that the spacer 210 be registered with the apertures 46 and 47. A spacer 210 registered with the apertures 46 and 47 spaces a part of the diaper 20 underlying the apertures 46 and 47, such as a part of the absorbent core 44 or backsheet 4
57. Referring to FIGS. 3-4, aperture 47 is aligned with the aperture 46, and preferably has a shape the same as, or similar to, the shape of aperture 46. Preferably, the spacer 210 is registered with the apertures 46 and 47, such that spacer 210 does not sub
58. The backsheet 42 is preferably impervious to fluids, such as urine, and prevents fluids absorbed by and contained in the absorbent core 44 from wetting undergarments, clothing and bedding. As used herein the "backsheet" refers to any barrier disposed out
59. The backsheet 42 may be a polyolefinic film, such as polyethylene, having a thickness of about 0.01 millimeters to about 0.051 millimeters (0.0005 to 0.002 inches). If desired, the backsheet 42 may be embossed or matte finished to provide a cloth-like ap
60. Other suitable backsheet materials can include breathable materials that permit vapors to escape from diaper 20 while still preventing exudates from passing through backsheet 26. Exemplary breathable materials may include materials such as woven webs, no
61. Referring again to FIGS. 1 and 5, the spacer 210 can have a keyhole shape comprising a generally closed figure. The closed figure shape shown in FIGS. 1 and 5 provides the spacer 210 longitudinally disposed so that the end having the smaller lateral widt
62. The laterally extending portion 220 of spacer 210 is preferably disposed intermediate the front waist region 22 and the aperture 46, and extends between longitudinally extending portions 222. A laterally extending portion 224 is positioned intermediate t
63. Alternatively, the spacer 210 can have a shape comprising an open figure, such as shown in FIG. 2. A laterally extending portion 220 can connect longitudinally extending portions 222 to form a generally U-shaped configuration that opens rearwardly. Wher
64. Referring to FIGS. 5-7, a spacer 210 according to the present invention comprises one or more inflatable chambers 230. Inflatable chambers 230 can be formed by peripherally joining two chamber walls 232 and 234 at seams 240. A portion of chamber wall 23
65. Seams 240 can include seam extensions 242 for separating adjacent inflatable chambers 230, as shown in FIG. 5. Seam extensions 242 preferably extend laterally to provide one or more laterally extending hinge lines. Such hinge lines reduce the longitudin
66. Alternatively, the chamber walls 232 and 234 can be vacuum formed to provide such hinge lines.
67. The first and second materials 300 and 400 should be non-toxic and combine to evolve an inert gas which is non-toxic in the quantities generated. The first gas evolving material 300 is preferably a combination of a bicarbonate, such as sodium bicarbonate
68. The first material 300 is preferably soluble in the second activating material. The preferred second activating material 400 comprises water.
69. In an alternative embodiment, the first material 300 can comprise a bicarbonate and the second activating material 400 can comprise one of the above listed powdered acids dissolved in water.
70. The speed of inflation of the chamber 230 can be controlled by forming the first material 300 as a fine powder (rapid inflation), or as a compressed tablet (slow inflation). In addition, the first material 300 can have a coating that dissolves in the sec
71. Of course, the amounts of first and second materials 300 and 400 will vary depending upon the inflated volume of the chambers 230. The amounts of the bicarbonate and the powdered acid which are mixed to evolve a given volume of carbon dioxide when dissol
72. The breakable packet 500 should contain at least enough water or other activating second material 400 to dissolve the quantity of the first material 300 disposed in the chamber. The amount of water required will depend upon the solubility and quantity of
73. The first material 300 can be unconstrained in the inflatable chamber 230, or adhesively adhered to one the walls 232 and 234 to prevent the first material 300 from shifting during shipping and storage such that it is not adjacent breakable packet 500. M
74. The envelope 290 may be hydrophobic, or at least treated to be hydrophobic. The term "hydrophobic" can be defined in terms of the contact angle between a liquid and a surface. The American Chemical Society Publication "Contact Angle, Wettability, and Ad
75. More preferably, the envelope 290 comprises a gas permeable, liquid impermeable material or element so as to prevent any of the second activating material (e.g., water) from escaping into the inflatable chamber 230. This ensures that the second material
76. Another advantage of the present invention is that the rate of inflation of the inflatable chamber 230 may be controlled by varying the gas diffusion rate of the gas-permeable, liquid impermeable material. For example, decreasing the gas diffusion rate o
77. In one preferred embodiment, as shown in FIG. 5B, the envelope 290 comprises a gas impermeable material comprising an expansion control mechanism. As shown, the expansion control mechanism may include an inflation control mechanism such as gas release me
78. The MVTR of a sample is measured as follows: a known amount of CaCl.sub.2 is put into a flanged cup. A sample material is placed on top of the cup and held securely by a retaining ring and gasket. The assembly is then weighed and recorded as the initial
79. Suitable materials from which the walls 232 and 234 can be made include films, metallic foils and other substantially gas impermeable materials and laminates thereof. For instance, a suitable film is a polyethylene film having a thickness of from about 0
80. In certain embodiments, the gas evolving material may be disposed within an envelope comprising a water soluble film. In such embodiments, the gas evolving material is held within or behind the water soluble material. The water in the activating materia
81. The inflatable chambers 230 should preferably maintain an inflated thickness T2 of at least 0.635 centimeters (0.25 inch) for at least one hour, preferably at least three hours, and more preferably at least six hours when the spacer 210 is subjected to a
82. Such a material has machine direction tensile strength at rupture of between 790 to 1600 grams/centimeter (2000 to 4000 grams/inch), a machine direction tensile elongation at rupture of between about 400 to 700 percent, a cross machine direction tensile s
83. The tensile strengths and elongations listed above are measured using a constant rate of elongation tensile testing machine, such as an Instron Model 1122 made by the Instron Corp. of Canton, Ohio, operated at an elongation rate of 0.85 cm/sec (20 in/min
84. One or both of the walls 232 and 234 can be pre-formed, such as by thermoforming, vacuum forming or embossing. Referring to FIG. 7, wall 234 can be vacuum formed to provide a generally semi-circular cross-section upon inflation of chamber 230. Referring
85. The walls 232 and 234 can be joined to form seams 240 by any suitable joining method such as heat/pressure sealing, adhesive bonding, ultrasonic bonding, or the like. Suitable seams 240 can be formed using a Vertrod Thermal Impulse Heat Sealer Model 15MG
86. Referring to FIGS. 3 and 4, the spacer 210 can be joined to the diaper 20 by joining one of the walls, such as wall 232, to an underlying structure, such as the topsheet 38, backsheet 42, or absorbent core 44.
87. The spacer 210 can be joined to the underlying structure by any suitable joining method such as heat/pressure sealing, adhesive bonding, ultrasonic bonding, or the like. Suitable adhesives include the Century 5227 adhesive and the Findley Adhesive H2031
88. In FIG. 3, spacer 210 is joined to upper core layer 44U. Alternatively, in embodiments not having an upper core layer 44U, the spacer 210 can be joined directly to the topsheet 38 or the absorbent core 44. In FIG. 4 the lower core layer 44L is formed ar
89. Referring to FIG. 5, the breakable packet 500 can be formed by peripherally joining two flexible walls 532 and 534 along seams 540. A portion of the wall 534 is cut away in FIG. 5 to show the second material 400 contained in the packet 500. The two wall
90. The two walls 532 and 534 can be joined at seams 540 by any suitable method such as by heat/pressure sealing, adhesive bonding, ultrasonic bonding, or the like. Suitable seams 540 can be formed using the Vertrod Model 15MGC heat sealer listed above.
91. The wearer or diaperer may expand the spacer 210 by combining the first and second materials such as by squeezing the portions of the diaper 20 overlying and underlying the packet 500 between the thumb and forefinger or otherwise rupturing the packet 500.
92. In an alternative embodiment the packet 500 can be disposed in one of the front and rear waist regions 22, 24 so that it can be easily accessed before or after the diaper 20 is fastened to the wearer. For instance, the packet 500 and first material 300 c
93. The breakable packet 500 can be weakened to break along a predetermined direction so that the second activating material 400 is directed toward the first material 300. Referring to FIG. 5, the packet 500 can include a nozzle 542 formed by reducing the wi
94. The direction 552 is parallel to the machine direction of the material from which walls 532 and 534 are formed, and the direction 554 is parallel to the cross machine direction of the material from which walls 532 and 534 are formed. The machine directio
95. A suitable material for forming packet walls 532 and 534 and having a machine direction tensile elongation at rupture which is between about 1/3 and 1/2 the cross machine direction tensile elongation at rupture is available from Tredegar Industries of Ter
96. The tensile strengths and elongations listed above are measured using a constant rate of elongation tensile testing machine, such as an Instron Model 1122 made by the Instron Corp. of Canton, Ohio, operated at an elongation rate of 0.85 cm/sec (20 in/min
97. By way of an example, an inflatable spacer 210 having the above mentioned dimensions and formed from the above mentioned Tredegar C-8323 film can be inflated to a thickness T2 of about 1.27 centimeters (0.5 inch) with about 300 mg of ALKA-SELTZER and abou
98. Referring to FIGS. 2 and 9, the diaper 20 can include an expandable component 200 comprising a seal member 600 (shown in phantom in FIG. 2). The seal member 600 comprises a portion of a seal means for reducing leakage of body exudates from between the di
99. Above referenced U.S. Pat. No. 4,938,755 is incorporated herein by reference for the purpose of showing a suitable construction for the barrier cuffs 62 and 63. The seal member 600 will be described as it comprises a portion of a barrier leg cuff 62, i
100. The barrier leg cuff 62 has a proximal edge 64 joined to a side flap 58 in the crotch region 26 and a longitudinally extending distal edge 66 which is not attached to an underlying diaper structure in the crotch region 26. The barrier leg cuff 62 may inc
101. Referring to FIG. 9, the barrier leg cuff 62 has oppositely facing outward and inward surfaces 65, 67 extending between the proximal and distal edges 64, 66. The inward surface 67 faces an underlying diaper structure, such as topsheet 38. The seal membe
102. The seal member 600 is preferably inflatable and comprises at least one inflatable chamber 630 disposed intermediate the proximal and distal edges 64, 66. The inflatable chamber 630 can be formed between chamber walls 632 and 634 peripherally joined toge
103. The inflatable chamber 630 can comprise a generally longitudinally extending portion 652 and at least one generally laterally extending portion 654. The generally longitudinally extending portion 652 can be generally parallel to and juxtaposed with the p
104. The first material 300 and the breakable packet 500 containing the second activating material 400 can be enclosed in an envelope 290 (FIG. 5A) comprising a gas permeable material; a gas permeable, liquid impermeable material; or a gas impermeable material
105. The laterally extending portions 654 can extend intermediate the longitudinally extending portion 652 and the distal edge 66 of the barrier cuff 62. The laterally extending portions 654 can be interconnected by the longitudinally extending portion 652 su
106. Inflation of the laterally extending portions 654 causes chamber wall 634 to abut topsheet 38, and thereby bias the distal edge 66 apart from the topsheet 38. Because the inflated thickness of the longitudinally extending portion 652 is smaller than the
107. In the embodiments described above, the expandable component 200 is inflatable, and the first material 300 evolves gas upon combination with the second activating material 400. In an alternative embodiment, the first material 300 can comprise a material
108. For example, first material 300 can comprise a number of absorbent materials, including but not limited to absorbent foams, absorbent gelling materials, or superabsorbent polymers which swell or expand upon being wetted. A suitable superabsorbent materia
109. The diaper 20 is applied to the wearer by positioning the back waist region 24 under the wearer's back and drawing the remainder of the diaper 20 between the wearer's legs so that the front waist region 22 is positioned across the front of the wearer. Th
110. While particular embodiments and/or individual features of the present invention have been illustrated and described, it would be obvious to those skilled in the art that various other changes and modifications can be made without departing from the spiri
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