Patent Application
20060229582
This invention relates to disposable absorbent articles having multiple replaceable absorbent core components.
A typical disposable absorbent article includes an absorbent core for receiving and holding bodily exudates discharged by the wearer of the article and is designed to be removed and discarded once the absorbent core becomes saturated with bodily discharges, such as urine. Other parts of the disposable absorbent article may still be usable, and except for being unitary with the absorbent core, these parts could continue to be used. In addition to the added cost and waste associated with discarding reusable materials, it is often inconvenient to remove and replace the entire disposable absorbent article when only a portion is saturated.
Disposable absorbent articles having removable absorbent inserts and thereby being potentially usable for more than a single saturation are known in the art. However, because the absorbent insert typically is removable only from the interior, the over-garment must be removed from the wearer in order to remove the insert.
Accordingly, it would be desirable to provide a disposable absorbent article having a multi-piece absorbent core in which a primary absorbent core component is replaceable and forms a pocket inside which at least a portion of a replaceable secondary absorbent core component is contained, and in which at least the secondary absorbent core component is replaceable without having to remove the disposable absorbent article from the wearer.
The present invention is a disposable absorbent article adapted to be worn about a lower torso of a human body, including a chassis forming a waist opening and a pair of leg openings and having opposed waist regions and a crotch region intermediate the waist regions, a primary replaceable absorbent core component disposed in at least the crotch region, and a secondary replaceable absorbent core component disposed at least partially inside a pocket formed by the primary replaceable absorbent core component and in capillary liquid communication with the primary replaceable absorbent core component.
In the accompanying drawing figures, like reference numerals identify like elements in various embodiments of the present invention. Elements shown in some figures have been omitted from other figures for the purpose of clarity.
In this description, the following terms have the following meanings:
Disposable absorbent article: A device that is placed against or in proximity to the body of a wearer to absorb and contain the various exudates discharged from the body. An exemplary embodiment of the present invention is a disposable diaper, but the present invention is applicable to a range of disposable absorbent articles such as incontinence briefs, incontinence undergarments, diaper holders and liners, training pants, pull-on diapers, and the like.
Absorbent core: An element of a disposable absorbent article containing a material or a combination of materials suitable for absorbing, distributing, and/or storing bodily liquids.
Attach, attached: Terms referring to elements being connected or united by fastening, adhering, bonding, etc. by any method suitable for the elements being attached together and their constituent materials, such as adhesive bonding, pressure bonding, thermal bonding, mechanical fastening, etc. Elements may be permanently attached together, in which case their detachment results in damage to one or both. Alternatively, elements may be releasably attached together such that their detachment can be accomplished without damage.
Chassis: A foundational constituent upon which the remainder of the structure of a disposable absorbent article is built up, e.g., in a disposable diaper, the structure that gives the disposable diaper the form of briefs or short pants when configured for wearing. A backsheet is typically a fundamental element of the chassis, usually in combination with a topsheet and/or additional structural elements.
Disposable diaper: An absorbent article generally worn by infants and incontinent persons about the lower torso so as to encircle the waist and the legs of the wearer and specifically adapted to receive and contain urinary and fecal waste.
Disposable: A term used to describe an absorbent article that is not designed to be laundered or otherwise restored or reused as an absorbent article after being removed from a wearer following saturation of its absorbent core, but is instead designed to be discarded after a single use. Note that, as described in this disclosure, a single use of a chassis may correspond to several replacements of one or more replaceable absorbent core components.
Disposed: A term referring to an element being attached and positioned in a particular place or position in a unitary structure with other elements.
Capillary liquid communication: The flow of a liquid from one absorbent element to another absorbent element by capillary transport. Also, a term used to describe a structural disposition of absorbent elements in which the flow of a liquid between them occurs through capillary transport of the liquid, requiring either the direct face-to-face contact of the absorbent elements with each other, the direct face-to-face contact of each of the absorbent elements with a hydrophilic intermediate layer providing capillary conduction of the liquid from one absorbent element to the other, or the protrusion of the fibers of a fibrous absorbent element through a porous and/or permeable intermediate layer into contact with the other absorbent element.
Interior and Exterior: Terms referring respectively to the location of an element that is intended to be placed against or toward the body of a wearer when an absorbent article is worn and the location of an element that is intended to be placed against or toward any clothing that is worn over the absorbent article. Synonyms for “interior” and “exterior” include, respectively, “inner” and “outer”, as well as “inside” and “outside”. Also, when the absorbent article is oriented such that its interior faces upward, e.g., when it is laid out in preparation for setting the wearer on top of it, synonyms include “upper” and “lower” and “top” and “bottom”, respectively.
Instructions: A term referring to an outline or delineation of steps to be performed. The descriptive nature of the instructions may be provided by text, by figures or diagrams, or by any other visual guide, such as by the sequential numbering of operations or of operable devices in correspondence with an effective sequence of steps of a method. The instructions may take any of several forms. For example, the instructions may be printed on the outside or the inside of an article of commerce, such as a package, itself, or may be in the form of a sheet or card contained inside or attached to a package. In some embodiments, the instructions may form part of the physical embodiment of a usable article as, for instance, when the instructions are printed on or affixed to a disposable diaper. In general, the instructions may be provided in any form in which the functional relationship between the instructions and the use of the article is clear to the user.
Lateral: A term referring to a direction running from a side edge to an opposing side edge of the article and generally perpendicular to the longitudinal direction. Directions within ±45° of the lateral direction are considered to be “lateral”. The “width” of a component refers to its dimension in the lateral direction.
Longitudinal: A term referring to a direction running from a waist edge to an opposing waist edge of the article, generally parallel to the maximum linear dimension of the article and perpendicular to the lateral direction. Directions within ±45° of the longitudinal direction are considered to be “longitudinal”. The “length” of a component refers to its dimension in the longitudinal direction.
Replaceable: A term used to describe the structural form of a component of a disposable absorbent article that can be replaced without damage to either the replaceable component or to any other part of the article, that is, that can be removed and for which a like component can be substituted in place of the removed component, without such damage. The structure must be adapted to allow for both the removal and the insertion of a component designated as replaceable. Thus, this term embraces an arrangement of structural elements in such a way as to make the designated component replaceable, in contrast to other arrangements of structural elements in ways that make other components non-removable and therefore non-replaceable.
Water-permeable and Water-impermeable: Terms referring to the penetrability of materials in the context of the intended usage of disposable absorbent articles. Specifically, the term “water-permeable” refers to a layer or a layered structure having pores, openings, and/or interconnected void spaces that permit liquid water to pass through its thickness in the absence of a forcing pressure. Conversely, the term “water-impermeable” refers to a layer or a layered structure through the thickness of which liquid water cannot pass in the absence of a forcing pressure. A layer or a layered structure that is water-impermeable according to this definition may be permeable to water vapor and thus “breathable”. As is well known in the art, a common method for measuring the permeability to water of the materials typically used in absorbent articles is a hydrostatic pressure test, also called a hydrostatic head test or simply a “hydrohead” test. Suitable well known compendial methods for hydrohead testing are approved by INDA (formerly the International Nonwovens and Disposables Association, now The Association of the Nonwoven Fabrics Industry) and EDANA (European Disposables And Nonwovens Association). For the present purpose, the terms “permeable” and “impermeable” are considered to be interchangeable with “permeable” and “impermeable”, respectively.
Body-facing: A term referring to the elements of the chassis or absorbent core that form the interior surface of the disposable absorbent article, such as the topsheet, the leg cuffs, and the side panels, etc., when such elements are present.
In the exemplary embodiments shown in
The multi-piece absorbent core 10 shown in
An advantage provided by a multi-piece absorbent core is the capability to independently choose values for selected characteristics of the absorbent core components, such as liquid acquisition rates, liquid distribution rates, liquid storage capacities, interfacial liquid transfer rates and efficiencies, thicknesses, functionalities, and shapes or configurations. For example, in terms of liquid handling, the primary absorbent core component preferably has suitable liquid acquisition and distribution characteristics, while each secondary absorbent core component preferably has suitable liquid redistribution and storage characteristics. Two or more absorbent layers may form a primary replaceable absorbent core component, with the innermost layer having relatively greater liquid acquisition characteristics and the outer absorbent layer(s) having relatively greater liquid distribution characteristics. In this configuration, a liquid bodily discharge such as urine can be quickly acquired by the body-facing acquisition layer and can then be desorbed into the adjacent distribution layer(s), which can distribute it throughout the length of the primary replaceable absorbent core component. A secondary replaceable absorbent core component that is disposed in capillary liquid communication with the distribution layer(s) can then absorb the liquid and redistribute and store the liquid inside itself.
Thus, it becomes practical to assemble a disposable absorbent article of the present invention in a unique configuration suited for a particular use by placing a primary replaceable absorbent core component in position in at least the crotch region and placing a secondary replaceable absorbent core component in position such that it extends from one of the waist regions into the crotch region and is disposed in capillary liquid communication with the primary replaceable absorbent core component. If desired, another secondary replaceable absorbent core component may be placed in position such that it extends from the opposing waist region into the crotch region and is likewise disposed in capillary liquid communication with the primary replaceable absorbent core component.
For example, a primary replaceable absorbent core component having relatively fast liquid acquisition and distribution characteristics can be assembled together with a secondary replaceable absorbent core component having relatively high redistribution and storage characteristics, such as for use in keeping the skin of an infant dry at all times and especially during an extended period of sleep. Alternatively, a primary replaceable absorbent core component having relatively slow liquid acquisition and distribution characteristics can be assembled together with a secondary replaceable absorbent core component having relatively low redistribution and storage characteristics, such as for use in toilet training an older child for whom a feeling of wetness may facilitate recognition of an initial release of urine and/or a desire to use the toilet, rather than voiding into a disposable diaper. As another example, a primary replaceable absorbent core component having relatively fast liquid acquisition and distribution characteristics can be assembled together with a secondary replaceable absorbent core component having relatively low redistribution and storage characteristic, such as for use during brief absences from the home, when both keeping the wearer's skin dry and minimizing the bulk of the disposable diaper are important considerations.
Such assembly of the disposable absorbent article may be done at any time from manufacture to use, including in steps at different times so as to complete the assembly at the point of use. For example, a fully assembled disposable absorbent article may be provided in an article of commerce, such as a package. Alternatively, the chassis and one or both of the replaceable absorbent core components may be provided separately, either in the same article of commerce or separately. In any of these situations, instructions may be provided for assembling the disposable absorbent article as described in this disclosure.
An additional benefit resulting from the use of a multi-piece absorbent core is the capability to independently replace an absorbent core component to renew the functionality of that portion of the disposable absorbent article. For example, when a replaceable absorbent core component becomes saturated with bodily liquid, it may be removed and a fresh unsaturated like replacement absorbent core component may be inserted in its place to renew the associated portion of the absorptive capacity of the disposable absorbent article. In particular, as a secondary replaceable absorbent core component becomes saturated, it may become less effective at absorbing liquid from the primary replaceable absorbent core component. Consequently, the primary replaceable absorbent core component may become relatively more highly saturated and its ability to draw liquid away from the wearer's skin my be hindered. However, a replacement of the secondary replaceable absorbent core component renews the functionality of absorbing liquid from the primary replaceable absorbent core component. This replacement thereby leads to a reduction in the level of saturation of the primary replaceable absorbent core component and to a renewal of its ability to draw liquid away from the wearer's skin. Thus, the present invention makes it practical to renew the disposable diaper by way of a simple replacement of a replaceable absorbent core component.
The backsheet is compliant and readily conforms to the shape and contour of the wearer's body. The backsheet may include a water-impermeable material such as a thin plastic film in order to prevent the exudates absorbed and contained in the absorbent core from wetting external articles, such as bed sheets and clothing, which contact the disposable diaper. The backsheet may include a nonwoven layer disposed exteriorly of a film layer in order to provide a cloth-like appearance and feel on the exterior of the disposable diaper. The backsheet may be “breathable”, i.e., water vapor-permeable, but water-impermeable, and thereby permit water vapor to escape from the absorbent core while preventing liquid exudates from escaping.
The topsheet is compliant, soft feeling, and non-irritating to the wearer's skin. At least a portion of the topsheet is water-permeable, thus permitting bodily liquids to readily penetrate through its thickness. A suitable topsheet can be manufactured from a wide range of materials such as woven and nonwoven materials, films, foams, and scrims. Suitable woven and nonwoven materials can include natural fibers, synthetic fibers, and/or combinations of natural and synthetic fibers. Preferably, the topsheet is made of a hydrophobic material to isolate the wearer's skin from liquids that have passed into the absorbent core.
It is also contemplated that a suitable absorbent core structure could be used without a topsheet to provide desirable results, such as comfort and absorbency, as well as simplicity in manufacturing and material cost savings. For example, the body-facing surface of the absorbent core could be made of a water-permeable, soft, compliant, non-irritating material, thereby making a separate topsheet unnecessary.
A portion of the backsheet and/or the topsheet may be subjected to mechanical stretching to form an extensible “zero strain” stretch laminate where such extensibility is desired, for example in elastic side panels. Suitable equipment and processes for such mechanical stretching and for the formation of such a zero strain stretch laminate are described in U.S. Pat. No. 5,143,679 to Weber et al., U.S. Pat. No. 5,156,793 to Buell et al., and U.S. Pat. No. 5,167,897 to Weber et al.
The chassis 1 of the disposable diaper may have an “open” configuration, as shown in
The disposable diaper may have extensible side panels 210, which preferably are elastically extensible, in order to maximize the ease of insertion and removal of the replaceable absorbent core components.
Leg elastic members 69 may be disposed adjacent to the periphery of the disposable diaper, preferably along each longitudinal edge 64 to form an elastically contractible leg cuff or side flap, so that the elastic members tend to draw and hold the disposable diaper against the legs of the wearer. The leg elastic members may extend along any portion of the length of the disposable diaper, up to and including the entire length.
A barrier leg cuff 240 including a barrier leg cuff elastic member 241 may be disposed adjacent to each longitudinal edge 64 or between the longitudinal edge and the longitudinal axis 17 of the disposable diaper. Suitable barrier leg cuff materials and structures are described in U.S. Pat. No. 4,695,278 to Lawson, U.S. Pat. No. 4,816,025 to Foreman, and U.S. Pat. No. 4,808,178 to Aziz et al.
Waist elastic members 67 may be disposed in either the front, the back, or both of the waistband regions 63 of the disposable diaper. A suitable elasticized waist structure is described in U.S. Pat. No. 4,515,595 to Kievit et al.
The primary replaceable absorbent core component 50 may be generally rectilinear in shape, i.e., it may have a generally constant width 53 along its length, or it may vary in width along its length. At least adjacent to the lateral axis 18, its width 53 preferably is suitable for comfortably fitting within the crotch area of the wearer.
The primary replaceable absorbent core component is disposed in at least the crotch region 66. In some embodiments, the primary replaceable absorbent core component may extend into one or both of the waist regions. For example, as shown in
The primary replaceable absorbent core component may be entirely free to “float” within the disposable diaper or may be releasably attached to another element over a part or the whole of any of its surfaces. For example, the primary replaceable absorbent core component may be releasably attached to the topsheet or to the backsheet or to both, and may be so attached in the crotch region. When such attachment is in the crotch region, the portions of the primary replaceable absorbent core component in the waist regions may remain unattached and thereby free to “float”. Alternatively, only either the front portion or the back portion of the primary replaceable absorbent core component may be releasably attached and the longitudinally opposing portion may be allowed to float. Any such floating portion of the primary replaceable absorbent core component may form a pocket between the primary replaceable absorbent core component and the topsheet or the backsheet to receive and hold at least a portion of a secondary replaceable absorbent core component. For example, such a pocket 5 is shown between the primary replaceable absorbent core component 50 and the backsheet 62 in
As depicted in
It is preferred that a secondary replaceable absorbent core component extend into the crotch region no farther than the lowest point of the disposable diaper in the crotch of the wearer, so that it can be removed and replaced without the necessity of passing any portion of it, or the hand of the caregiver, or an insertion tool, through the wearer's crotch. Nevertheless, because the inner end can be shaped to fit comfortably into the crotch area of the wearer's body, the inner end can be optimally positioned for the absorption of liquid from the primary replaceable absorbent core component, which extends through the wearer's crotch and thus can serve to transport liquid from the front waist region to the back replaceable absorbent core component or from the back waist region to the front replaceable absorbent core component.
As shown in
When both front and back secondary replaceable absorbent core components are present, they preferably are disposed such that the inner front end 22 of the front replaceable absorbent core component 20 is spaced from the inner back end 32 of the back replaceable absorbent core component 30 as shown in
Like the primary replaceable absorbent core component, each secondary replaceable absorbent core component may be entirely free to “float” within the disposable diaper or may be releasably attached to another element over a part or the whole of any of its surfaces. For example, a secondary replaceable absorbent core component may be releasably attached to the topsheet or to the backsheet or to the primary replaceable absorbent core component.
Each of the primary and secondary replaceable absorbent core components may include multiple layers of absorbent material and each layer may have individual liquid handling characteristics, as well as an individual shape, width, length, and thickness. The number and placement of these absorbent layers may be varied to achieve desired characteristics, such as thinness, softness, flexibility, liquid acquisition rate, liquid distribution rate, and/or liquid storage capacity. For example, if the thickness of an individual layer of the primary replaceable absorbent core component would be detrimental to a wearer's comfort, this layer may not extend through the crotch region.
Several exemplary arrangements of the replaceable absorbent core components with respect to each other are shown in the figures. In the exemplary embodiment shown in cross section in
In
As another example, in
Access to the replaceable absorbent core components may be provided at an aperture in the backsheet. For example, in the exemplary embodiment shown in
Access to the replaceable absorbent core components may be provided at a predetermined area of the periphery where the topsheet and the backsheet are separable to form an opening for the removal and/or insertion of the replacement absorbent core components. An example of such a structure is shown in cross-section in
Suitable structures providing access to the replaceable absorbent core components are described in co-pending U.S. patent application Ser. No. 10/308,430 filed on 3 Dec. 2002 in the name of LaVon et al. and published as U.S. Patent Application Publication No. U.S. 2003/0199844 A1 on 23 Oct. 2003.
Typical absorbent materials known in the art may be used for the replaceable absorbent core components, such as fibrous nonwoven materials, fibrous air-laid materials, fibrous wet-laid web materials, and/or combinations of fibrous materials having polymeric absorbent gelling materials dispersed upon or within the fibrous structure. Suitable absorbent materials may also be foam-based. Particularly suitable absorbent foams have been made from high internal phase emulsions. Exemplary materials and structures that may be utilized in the absorbent core structure of the present invention are described in U.S. Pat. No. 5,531,728 to Lash, U.S. Pat. No. 5,147,345 to Young et al., U.S. Pat. No. 5,800,416 to Seger et al., U.S. Pat. No. 6,372,953 to Young et al., U.S. Pat. No. 5,260,345 to DesMarais et al., U.S. Pat. No. 5,268,224 to DesMarais et al., U.S. Pat. No. 5,387,207 to Dyer et al., and U.S. Pat. No. 5,563,179 to Stone et al. The absorbent core components may also include a combination of absorbent materials, for example, a combination of foam and wood pulp or other cellulosic fibers and/or particles or fibers of a polymeric absorbent gelling material.
Suitable materials and constructions for the replaceable absorbent core components are also described in the LaVon et al. '430 application. In particular, the primary replaceable absorbent core component of the present invention can be constructed similarly to the center section of the absorbent core in the LaVon et al. '430 application, with the exception that it must be made replaceable in the present invention. Likewise, the secondary replaceable absorbent core components of the present invention can be constructed similarly to the front and back panels of the LaVon et al. '430 application. Each absorbent core component may be formed into a packet in which the absorbent material is partially or wholly covered and/or enveloped by a water-permeable web material providing sufficient structural integrity for its handling during removal and replacement. The use of such a covering and/or enveloping material on the body-facing surface(s) of the absorbent core component(s) may obviate the need for a separate topsheet.
The relationship of the capillary absorption pressure of one absorbent element and the capillary desorption pressure of another absorbent element defines the liquid flow, liquid transfer, and capillary liquid communication characteristics of the disposable absorbent article. In particular, as is well-known in the art, liquid is absorbed from one layer to the next, from an acquisition layer to a storage layer, for example, if the absorbing layer's capillary absorption pressure exceeds the desorption pressure of the donating layer. This principle is that of a capillary cascade and suitable materials and ranges of properties are described in the Young et al. '345 patent and U.S. Pat. No. 5,906,602 to Weber et al.
For example, the wearer-facing layer of the disposable absorbent article, e.g., a topsheet, is water-permeable and has particular capillary absorption and desorption pressures. The capillary desorption pressure of this topsheet is preferably less than the capillary absorption pressure of the primary replaceable absorbent core component and, specifically, less than the capillary absorption pressure of the uppermost absorbent layer of the primary replaceable absorbent core component, with which the topsheet will be in contact. In addition, it is preferred that the absorption pressure of a lower absorbent layer of the primary replaceable absorbent core component be greater than the capillary desorption pressure of the uppermost absorbent layer of the primary replaceable absorbent core component, such that liquid will be drawn toward this lower layer and away from the topsheet. Furthermore, it is preferable that the capillary absorption pressure of the secondary replaceable absorbent core component be greater than the capillary desorption pressure of the absorbent layer of the primary replaceable absorbent core component in contact with it, such that liquid will be drawn from the primary replaceable absorbent core component into the secondary replaceable absorbent core component.
The disposable absorbent articles of the present invention are preferably constructed such that liquid deposited in the article is quickly absorbed into the primary replaceable absorbent core component and then moved into the secondary replaceable absorbent core component. In order to minimize the overall bulk and to maximize the benefits of skin health and dryness, it is preferable that the primary replaceable absorbent core component have a liquid storage capacity that is low relative to the total capacity of the absorbent core, i.e., relative to the total of the summed capacities of the primary and secondary replaceable absorbent core components. Furthermore, it is desirable to remove the majority of the liquid deposited in the article by removing the secondary replaceable absorbent core component for replacement with a fresh dry absorbent core component. Therefore, the liquid absorptive capacity of the secondary replaceable absorbent core component is preferably at least about 1.5 times, more preferably at least about 2 times, and most preferably at least about 4 times as great as the liquid absorptive capacity of the primary replaceable absorbent core component.
All documents cited in the Detailed Description of the Invention are incorporated herein by reference. It is expressly not admitted that any such document constitutes prior art with respect to the present invention. To the extent that any meaning or definition of a term in this document conflicts with any meaning or definition of the term in an incorporated document, the meaning or definition assigned to the term in this document shall govern.
While particular exemplary embodiments 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 spirit and scope of the present invention. It is therefore intended to cover in the appended claims all such changes and modifications that are within the scope of the present invention.
