Absorbent article and method of making same

0001This invention pertains to disposable absorbent articles.

0002Currently, disposable diapers or other absorbent articles find wide spread use in infant and adult incontinence care, and have generally replaced reusable or washable cloth absorbent articles. A typical disposable diaper or other absorbent article is a three-layered composite structure comprising a liquid-permeable top-sheet, a liquid-impermeable backsheet, an absorbent assembly between the topsheet and backsheet, and a means for fastening the diaper or article to the wearer.

0003Such absorbent articles are known from US-A-4,662,877 and EP-A-0 343 940, for example.

0004A further device for the collection of bodily excretion is disclosed in US-A-4,950,262. This device comprises a backsheet, a topsheet and an absorbent located therebetween. In order to absorb and hold a large amount of excretion, the device has a guide strip for directing the flow of the excretion toward an expandable storage member.

0005Although current diapers or other absorbent articles have been generally accepted by the public, they still have need of improvement in certain areas, and particularly in the area of isolating and containing waste material away from the skin of the wearer. Although current diapers or absorbent articles have been generally satisfactory in preventing leakage of urine outside of the diaper or absorbent article, the waste material contained therein too often is in contact with the skin of the wearer. If this contact between waste material and the skin is prolonged over a period of time, it can cause undesirable effects such as skin dermatitis, skin hydration, or messy clean-ups.

0006The present invention provides a diaper or absorbent article that is pocket-like in shape and which receives, isolates, and contains waste material away from the skin of the wearer.

0007Therefore the present, invention provides a disposable absorbent article according to independent claim 1 and a method of making same according to independent claim 36.

0008Further advantageous features, aspects and details of the invention are evident from the dependent claims, the description and the drawings. The invention refers particularly to a pocket like diaper or absorbent article that improves the isolation and containment of waste material from the body.

0009The diaper or absorbent article of the invention is pocket-like in shape and receives, isolates, and contains waste material away from the skin of the wearer.

0010In one form of the present invention there is provided an absorbent article comprising a backsheet, a topsheet having an opening, an absorbent between the backsheet and topsheet, and an elevating device below the topsheet that spaces the topsheet above the absorbent, thereby forming a pocket-like shape for isolating and containing waste material.

0011In one aspect the topsheet is generally U-shaped and oriented such that the opening of the "U" faces toward the front edge of the absorbent article.

0012In another aspect the absorbent can include a pair of absorbent panels disposed on opposite sides of the absorbent and a pair of elastic members that are attached in a stretched condition to cause the absorbent panels and absorbent to form a pocket-like shape.

0013The above-mentioned and other features and objects of this invention, and the manner of obtaining them, will become more apparent and the invention itself will be better understood by reference to the following description of the embodiment of the invention taken in conjunction with the accompanying drawings, wherein: <ul id="ul0001" list-style="none" compact="compact"><li>Fig. 1 is a top plan view of one embodiment of the present invention;</li><li>Fig. 2 is a bottom plan view of the embodiment in Fig. 1;</li><li>Fig. 2A is a perspective view of the embodiment in Fig. 1;</li><li>Fig. 3 is a plan view of one absorbent structure of the present invention;</li><li>Fig. 4 is a cross-sectional view of the absorbent structure in Fig. 3 taken along line 4-4;</li><li>Fig. 5 is a plan view of a second absorbent structure of the present invention;</li><li>Fig. 6 is a cross-sectional view of the absorbent structure in Fig. 5 taken along line 6-6;</li><li>Fig. 7 is a plan view of a liner assembly of the present invention;</li><li>Fig. 8 is an exploded view of the embodiment in Fig. 1;</li><li>Fig. 9 is a plan view of one assembly of an absorbent structure and a backsheet of the present invention; and</li><li>Fig. 10 is a plan view of a second assembly of an absorbent structure and a backsheet of the present invention.</li></ul>

0014The absorbent article of the present invention can be utilized as a baby diaper, adult incontinence garment, and the like. For purposes of the present discussion, the absorbent article will be described in terms of a baby diaper designed to fit a baby weighing between about 12-24 pounds, but it is understood that the features and principles of the present invention apply to other sizes.

0015Referring to Figs. 1, 2, 2A, and 8, absorbent article or diaper 10 of the present invention comprises top-sheet 12 and backsheet 14 having positioned therebetween absorbent assembly 16. Absorbent assembly 16 includes absorbent structure 18, pledget 20, and hole 22. Masking layer 24 is positioned between absorbent assembly 16 and backsheet 14 so as to underlie hole 22. Cleft block 26 is positioned below or underneath topsheet 12 to elevate a portion of topsheet 12 from absorbent assembly 16, thereby forming a pocket-like structure or shape. Diaper 10 further comprises elasticized side flaps 28, containment flaps 30, and stretchable ears 32. In order to fasten diaper 10 onto a baby, fasteners 34 are provided on ears 32, and in this particular embodiment fasteners 34 comprise hook material 36 on ears 32 and loop material 38 on backsheet 14. Fasteners 34 may also be or include other types of mechanical fasteners, adhesive tapes, and the like.

0016Referring to Figs. 7 and 8, topsheet 12 initially is generally rectangular in shape and comprises a front section 40, back section 42, and crotch section 44. In Fig. 8, a finished topsheet 12 has a generally U- or horseshoe-shape in which the elongate portions form containment flaps 30. With reference to Fig. 7, the horseshoe-shape is manufactured by tucking or folding a cut portion of topsheet 12 upon itself starting at longitudinal centerline or cut-line 46 and extending between front edge 48 to a point in back section 42 identified as apex 50. Prior to cutting and folding topsheet 12 upon itself to form containment flaps 30, an elastic member 52 is applied in a stretched condition in crotch section 44 adjacent to and outboard of, relative to cut-line 46, its respective longitudinal fold-line 54. Elastic members 52 are then covered by topsheet 12 in the cutting and folding step. Each portion of topsheet 12 between cut-line 46 and a longitudinal fold-line 54 is folded against and attached to the remaining portion of topsheet 12 to form folded portions 56 (Fig. 8). During the cutting and folding operation, that part of folded portion 56 near apex 50 is cut and folded along respective fold-lines 58 that converge to apex 50. Fold-lines 58 converge from respective points 60. Alternatively, each portion of top-sheet 12 between cut-line 46 and a longitudinal fold-line 54 is cut and removed from topsheet 12, and elastic members 52 are then attached in a stretched condition to flaps 30.

0017Important to the invention is the spacing between elastic members 52, and the height or width of each containment flap 30 measured in a direction generally perpendicular to cut-line 46. If each elastic member 52 is a single rope, thread, or ribbon of material, the spacing is measured between the mutually facing, innermost edges of the ropes, threads, or ribbons in their stretched condition. The present invention also contemplates each elastic member 52 being a plurality of individual ropes, threads, or ribbons of elastic material. In this latter case, the spacing is measured between the innermost rope, thread, or ribbon of each elastic member 52 in their stretched condition. For example, Figs. 7 and 8 illustrate each elastic member 52 comprising two ropes or filaments of elastic material placed in a spaced-apart and generally parallel manner near a respective longitudinal fold-line 54. The spacing between elastic members 52 is then measured between the mutually facing sides of the innermost ropes or filaments of material. Because the elastic members 52 are attached in a stretched condition, at least in a portion of crotch section 44, upon relaxation, they cause containment flaps 30 to move out of the plane of topsheet 12 and to gather.

0018As mentioned above, the spacing between elastic members 52 and the height or width of containment flaps 30 is important to the invention. For example, if elastic members 52 are spaced too close together and/or containment flaps 30 are too wide or too high, flaps 30 can move into the cleft of the buttocks. This may eventually result in waste material leaking onto the bodyside or top surface 62 (Fig. 8) of topsheet 12, thereby contaminating the baby's skin and making clean-up more difficult and unpleasing. If elastic members 52 are spaced too far apart and/or containment flaps 30 are too short or too narrow, flaps 30 may not seal sufficiently against the body, thereby potentially allowing waste material to pass over the sides of containment flaps 30.

0019Elastic members 52 are preferably spaced apart approximately 4.5 centimeters in the attached stretched condition. A preferable range of spacing is from about 2 centimeters to about 7 centimeters, and a maximum spacing is from about 1 centimeter to about the total width of diaper 10.

0020The length of elastic members 52 in the attached stretched condition is about 19 centimeters in the present embodiment and, depending upon other factors, can be between about 7 centimeters to the entire length of diaper 10. A preferred range is between about 12 centimeters to about 30 centimeters. The length of elastic members 52 can also be defined in terms of the overall length of diaper 10. The length of each elastic member 52 can be between about 30% to about 85% of the length of diaper 10, and preferably about 40% to about 60%.

0021In one embodiment, each elastic member 52 is two strands of 470 Decitex Lycra (Decitex being the weight in grams of a single thread which is 10,000 meters long) that are 19 centimeters long when elongated 250 percent. Naturally, any number of strands, including only one, can be used for each elastic member 52 in order to properly and fully elasticize containment flaps 30.

0022Elastic members 52 are preferably designed to gather containment flaps 30 within the area of crotch section 44 such that the gathered portions of flaps 30 longitudinally terminate between about 2 centimeters to about 10 centimeters from the back and front edges 66, 67 of diaper 10.

0023As earlier stated, the height or width of containment flaps 30 is also important to the present invention. A preferred height or width of each containment flap 30 is about 3.5 centimeters. However, depending upon the overall size of diaper 10, each containment flap 30 can have a height or width between about 1 centimeter to about half the total width of diaper 10, and more preferably between about 1 centimeter to about 6 centimeters. The height or width of a containment flap 30 is measured between its respective fold-line 54 and the line where the flap is integral with or joined to topsheet 12.

0024Returning now to Fig. 8, although opening 64 in topsheet 12 is illustrated as having a generally rectangular shape, opening 64 can be of any shape. In this particular embodiment, opening 64 has a preferred area of about 130 square centimeters. Depending upon the size of diaper 10, this area of opening 64 can range between about 30 square centimeters to about 400 square centimeters, and preferably within the range between about 60 to about 260 square centimeters. Another method of determining or measuring the preferred size of opening 64 is as a percentage of the total area of topsheet 12. For example, in the particular embodiment illustrated, opening 64 comprises about 25 percent of the surface area of topsheet 12. In other embodiments of the present invention, opening 64 can comprise between about 10 percent to about 80 percent of the surface area of topsheet 12.

0025In forming opening 64 in topsheet 12, it is important that the back of opening 64, such as at apex 50, is positioned so that it is at least 1 centimeter to the back of and preferably above the level of the baby's anus. Another means of measuring the proper placement of opening 64 is in relation to back edge 66 of diaper 10, and in this particular embodiment the back edge of opening 64 is spaced approximately 7 centimeters from back edge 66. Again, depending upon the size of diaper 10, the back edge of opening 64 can be spaced from back edge 66 in a range between about 1 centimeter to about 10 centimeters.

0026Referring now to Figs. 3, 4, and 8, absorbent structure 18 is generally hour-glassed shaped, although it may also take on other geometric shapes such as a generally rectangular or T-shape, and includes hole 22. In this particular embodiment, hole 22 is shaped as a trapezoid having front edge 68, back edge 70, and sides 72. Front edge 68, in this embodiment, has a width of about 2.5 centimeters, back edge 70 has a width equal to about 4 centimeters, and sides 72 have a length of about 10 centimeters. Front edge 68 is positioned about 14 centimeters from front edge 67 of diaper 10 or about 12.5 cm from front edge 74 of absorbent structure 18. Front edge 68 may also be in the range from about 5 cm to about 20 cm from front edge 67 or front edge 74. In order to insure that waste material is received and maintained in hole 22, front edge 68 must also be positioned at least about 1 centimeter in front of the baby's anus. Again, the geometric shape and dimensions of hole 22 will depend, among other things, on the overall size of diaper 10. Generally, hole 22 has an area of about 32 cm², and can have an area within the range of about 5 to about 100 cm² and preferably in a range between about 15 to about 65 cm².

0027Hole 22 should also have adequate depth to provide a space or void area to receive and contain feces. In one embodiment, hole 22 has a depth of about 1 centimeter to receive and contain feces. This depth of hole 22 will naturally vary depending upon the size of diaper 10 and the absorbent materials of which absorbent assembly 16 is made. Consequently, hole 22 can have a minimum depth of about 1 millimeter. There is a preferred relationship between opening 64 in topsheet 12 and hole 22 in absorbent structure 18. The back of opening 64, designated as numeral 50 for example, can be located between about 1 centimeter from diaper back edge 66 to about 1 centimeter from front edge 68 of hole 22. More preferably, the back of opening 64 can be located between about 2 centimeters behind back edge 70 of hole 22 to about 2 centimeters behind front edge 68 of hole 22.

0028Horseshoe-shaped pledget 20 is positioned on absorbent structure 18 preferably without covering or closing off any portion of hole 22, as illustrated in Fig. 3. Pledget 20 serves several purposes, such as increasing the volume of the void space created by hole 22 and providing additional absorbent material. Superabsorbent material may also be added to pledget 20 or to both pledget 20 and absorbent structure 18 in order to increase absorbency and/or the volume of the void space of hole 22 upon swelling of the superabsorbent material during an insult. As illustrated, horseshoe-shaped pledget 20 has a length of about 12.5 centimeters and a width of about 5 centimeters. Preferably, the open end of pledget 20 is positioned to face forward or toward the front of diaper 10. However, it can face the back of diaper 10, totally encircle hole 22, or be a series of two or more smaller pledgets of various shapes. Generally, pledget 20 will have a length in the range between about 8 centimeters to the maximum length of absorbent structure 18, a maximum width equal to the width of absorbent structure 18, and a depth between about 1 millimeter to about 3 centimeters.

0029Pledget 20 and absorbent structure 18, either singly or together, can be enveloped by a layer of tissue or other material to maintain integrity of the absorbent material and to prevent migration of any superabsorbent present therein.

0030Referring to Figs. 5 and 6, absorbent structure 18 has an area 76 of zoned superabsorbent material encircling hole 22. Upon a urine insult of zoned area 76, the swelling of area 76 can provide additional space or void volume to receive and contain feces. Zoned area 76 can have any desired shape or density suitable for the particular absorbent structure desired.

0031Referring to Fig. 9, portions 79 of absorbent structure 18 have been cut-away to form leg cut-outs 80 and separate absorbent panels 78. Each panel 78 is spaced from absorbent structure 18, and a stretched elastic member 82 is then positioned between panel 78 and backsheet 14 and attached to one, two, or all of panel 78, absorbent structure 18, and backsheet 14, thereby forming a pocket-like shape; the attachment(s) can be to any portion of panel 78, absorbent structure 18, or backsheet 14, such as the sides or edges. Panel 78 can be trimmed, if desired, so that its outermost edge 84 is aligned with longitudinal edge 86 of absorbent structure 18. Upon relaxing stretched elastic member 82, panel 78 will curl or move upwardly. Panel 78 can be spaced away from leg cut-out 80 between about 1 millimeter to about 2 centimeters, and is preferably spaced apart between about 5 millimeters to about 1 centimeter.

0032In Fig. 10, integral absorbent panels 88 are formed by cutting absorbent structure 18 along cut-lines 90 and scored along score-line 92. Elastic members 83 are then attached in a stretched condition to one, two, or all of panel 88, absorbent structure 18, and backsheet 14; the attachment(s) can be to any portion of panel 88, absorbent structure 18, or backsheet 14, such as sides or edges. Upon relaxation of elastic members 83, panels 88 curl or move upwardly.

0033Referring to Figs. 1, 2A, 7, and 8, cleft block 26 is disposed below topsheet 12 and just slightly aft of opening 64. Cleft block 26 is important to the present invention in that it performs at least two desired functions. One of those functions is to aid in preventing fecal matter from moving up the cleft of the baby's buttocks. The second function is to space topsheet 12 above absorbent assembly 16 to form a pocket-like void, thereby allowing fecal matter to move underneath topsheet 12 rather than along its top and against the baby's skin.

0034Cleft block 26 can be made of any suitable material, such as a foam material, cellulosic material, a coform material comprising cellulosic and synthetic fibers, any synthetic or combination of synthetic fibers, and the like. Its geometric form is preferably rectangular in shape, but can be any suitable shape that functions as desired.

0035In this particular embodiment, cleft block 26 is approximately 4 centimeters long, 2 centimeters wide, and about 1 centimeter thick, and can be positioned between apex 50 and back edge 66 of diaper 10.

0036Referring to Figs. 1, 2A, and 7, masking layer 24 is at the base of absorbent hole 22 and generally on top of backsheet 14. Masking layer 24 can comprise an absorbent material and/or superabsorbent material, thereby acting as an additional absorbent layer. Another function of masking layer 24 is to prevent feces from possibly showing through backsheet 14. Preferably, masking layer 24 comprises two layers; a top layer made from the same material as the material enveloping pledget 20 and absorbent structure 18, thereby providing aesthetic continuity within absorbent assembly 16, and a bottom layer of a thermoplastic film having a thickness of at least about 0.5 mil.*

0037Referring now to Figs. 2 and 2A, backsheet 14 is preferably longer than topsheet 12 or absorbent assembly 16 and has a plurality of pleats 94 formed therein to permit expansion of backsheet 14. Pleats 94 can be formed in any suitable manner and can have any suitable dimensions. Pleats 94 are preferably formed in crotch area 96 of backsheet 14. In this particular embodiment, backsheet 14, when extended, is about 40 centimeters long and topsheet 12 is about 35 centimeters long. * 1 mil = .001 inch = 2.54 cm

0038Topsheet 12 can be a liquid-impermeable, hydrophilic or hydrophobic material, such as a spunbonded web composed of synthetic polymer filaments; a spunlace web; a spunbond-meltblown web; a meltblown web; or a bonded-carded web composed of synthetic polymer fibers. Suitable synthetic polymers include polyethylene, polypropylene, polyester, and nylon. In one embodiment, the polymer filaments have a denier within the range of about 1.5 to about 7 d,** and preferably within the range of about 1.2 to about 6.0 d. The filaments are arranged to form a layer having a basis weight within the range of about 10 to about 35 grams per square meter (gsm), and preferably a basis weight of about 20 gsm. Topsheet 12 can have a bulk thickness within the range of about 0.0140 to about 0.0432 centimeters, and preferably within the range of about 0.0180 to about 0.305 centimeters. The bulk thickness is measured under a restraining pressure of about 0.014 psi.*

0039Topsheet 12 also can be a Kraton meltblown/polypropylene spunbond stretch-bonded laminate which has been made wettable by addition of surfactants; a polyurethane spunbond material such as that manufactured by Kanebo Synthetic Fibers Company, Osaka, Japan, and made wettable by addition of surfactants; an elastomeric film made from elastomers such as rubber, latex rubber, polyurethane, Kraton, and the like, which has been perforated to allow fluid passage; a polyurethane foam which has been perforated to allow fluid passage; and a nonwoven which has been gathered through the use of elastic or other means, for example, heat-shrinkable fibers, to produce an elastically stretchable material.

0040Containment flaps 30 are generally of the same material as topsheet 12, although the present invention contemplates that portions of containment flaps 30 could be of a different material than the remaining portion of topsheet 12. For example, all or portions of flaps 30 can be vapor- and liquid-permeable, vapor-permeable and liquid-impermeable, or vapor- and liquid-impermeable.

0041Backsheet 14, in one embodiment, can be a liquid-impermeable material, and preferably a polyethylene film having a thickness of about 1.0 mil, although thicknesses above 0.50 mil are acceptable. Backsheet 14 can also be made of other materials that are suitably liquid-impermeable or treated to be so. Examples are meltblown or film material made of polypropylene or polyolefin copolymers such as ethylene vinyl acetate, ethylene methyl acrylate, ethylene ethyl acrylate, polyvinyl chloride, and the like. Other materials include a single spunbonded layer of the above types of material, two layers of spunbonded and meltblown materials, or three layers of material of spunbonded-meltblown-spunbonded material, each of which is suitably treated or coated to be liquid-impermeable. The same materials may also be provided in laminate form, the spunbonded materials provide an added feature of a cloth-like texture to backsheet 14. Backsheet 14 may also be made of the material that is not only liquid-impermeable, but also vapor-permeable. Backsheet 14 can also be made of materials which are easily expandable to provide more room for fecal evacuation and management. For example, backsheet 14 can be made of a microcreped material or materials, or can be made of an elastic material or materials. **1 denier = 1/9 tex = 1/9 g/km * 1 psi = .069 bar

0042Side flaps 28 are preferably made of a liquid-impermeable material that is vapor-permeable for increased air circulation in the crotch region, but may be made, if desired, from a liquid and vapor impermeable material or a liquid and vapor permeable material. Side flaps 28 can also have selected portions that are liquid permeable with the remaining portions being liquid-impermeable. Side flaps 28 can be formed from extensions of backsheet 14 and/or lateral sides of topsheet 12, or can be separate structural elements attached to backsheet 14 and/or topsheet 12. Side flaps 28 can be made of any materials of which topsheet 12 or backsheet 14 can be made.

0043Side flaps 28 are elasticized and can be made so in the same way that elastic members 52 elasticize containment flaps 30. Elastic members 52 can be any suitable elastic material, such as natural rubber, synthetic rubber, or thermoplastic elastomeric polymers, and can be single or multiple threads, filaments, or ribbons thereof. Optionally, these materials can be heat-shrinkable or heat-elasticizable. Preferably, each elastic member 52 comprises two or more strands or filaments of about 470-620 Decitex Lycra, and at 90 percent of ultimate elongation provide a tension between about 25 grams to about 150 grams. The material permits containment flaps 30 and side flaps 28 to retract from about 30 percent to about 80 percent of their elongated length. More preferably, the material has about 50 grams force after one minute hold-time at 90 percent ultimate elongation and the ability to retract to at least about 45 percent to about 50 percent of the original length.

0044Side flaps 28 preferably comprise two layers of 0.8 ounces per square yard (osy)* spunbonded polypropylene, and can be liquid permeable, liquid impermeable, or liquid impermeable-vapor permeable. For example, side flaps 28 can comprise at least one layer of a nonwoven, such as a spunbonded, bonded-carded web, or spun-laced material comprised of polymers such as polypropylene, polyethylene, polyester, or nylon. The material is preferably non-wettable (hydrophobic) in nature. This 0.8 osy side flap comprises a layer of 0.8 osy spunbonded polypropylene which is disposed over an elastic member, such as elastic member 52, to produce a two-layer flap.

0045Absorbent structure 18 and pledget 20 can be made of any suitable absorbent materials, can comprise the same absorbent materials, or comprise a different combination of absorbent materials. The absorbent materials can include cellulosic fibers, synthetic fibers, absorbent gelling materials in the form of particles, fibers, layers and the like, and various mixtures or blends thereof. Suitable absorbent gelling materials, i.e., superabsorbent materials, can be inorganic materials such as silica gels, or organic compounds such as cross-linked polymers. Some examples of superabsorbent or absorbent gelling material polymers include polyacrylamides, polyvinyl alcohol, polyacrylates, and the like. Other acceptable polymers include acrylonitrile grafted starch, acrylic acid grafted starch, modified carboxy methyl cellulose, and the like. * 1 osy = 33.91 g/m²

0046Absorbent structure 18 and pledget 20 can be individually wrapped in a tissue material, or wrapped as one assembly with a tissue material in order to maintain fiber integrity and to prevent migration of the superabsorbent material.

0047Masking layer 24 can also be made of any suitable material, such as those materials of which topsheet 12, backsheet 14, and absorbent assembly 16 are made, or mixtures thereof.