WO2001047455A1

WO2001047455A1 - Absorbent articles having a skin contacting surface that exhibits a reduced affinity for skin irritants

Info

Publication number: WO2001047455A1
Application number: PCT/US2000/033243
Authority: WO
Inventors: David Roland Otts; Frank Jerrel Akin; Dennis Stein Everhart; Eugenio Go Varona; Ali Yahiaoui
Original assignee: Kimberly-Clark Worldwide, Inc.
Priority date: 1999-12-23
Filing date: 2000-12-08
Publication date: 2001-07-05
Also published as: MXPA02006280A; EP1239801A1; AU2070901A

Abstract

An absorbent article for containing biological fluids that has a skin contacting surface with a reduced affinity for skin irritants is described. The absorbent article may include a liquid permeable bodyside liner that defines a bodyfacing surface; a backsheet located in facing relation to the bodyside liner; and an absorbent body located between the bodyside liner and the backsheet. The affinity between the bodyside liner and skin irritants found in the biological fluids is less than an affinity between the absorbent body and the skin irritants such that the skin irritants are drawn away from the skin of the wearer.

Description

ABSORBENT ARTICLES HAVING A SKIN CONTACTING SURFACE THAT EXHIBITS A REDUCED AFFINITY FOR SKIN IRRITANTS

Background of the Invention

Field of the Invention

The present invention relates to absorbent articles for absorbing body fluids and exudates, such as urine and fecal material. More particularly, the present invention relates to absorbent garments, such as disposable diapers and adult incontinence garments that are configured to absorb and contain biological fluids and absorb/adsorb skin irritants.

Description of the Related Art

Conventional absorbent articles, such as disposable diapers, employ absorbent materials located between a liquid pervious bodyside liner and a liquid impermeable backsheet to absorb body exudates. Such articles are well suited to absorb and contain biological fluids as well as prevent the migration of liquid materials from the absorbent materials to the outer garments of a wearer. Moreover, the improved absorbent capacity of such articles is such that the articles can be left on the wearer for extended periods of time before it is necessary to remove the soiled article, dispose of it and replace it with a new one. Unfortunately, with the extended use of such articles, the wearer's skin has remained susceptible to rashes, abrasion and irritation such as what is commonly referred to as diaper dermatitis or diaper rash. Moreover, the occlusive, moist environment inside such articles can exacerbate this problem by promoting the viability of microorganisms, including Candida albicans. Accordingly, there remains a need for absorbent articles that, in use, exhibit a lower incidence of rashes and irritation on the wearer's skin. Summary of the Invention

When employed in the present disclosure, the terms "comprises", "comprising" and other derivatives from the root term "comprise" are intended to be open-ended terms that specify the presence of any stated features, elements, integers, steps, or components, but do not preclude the presence or addition of one or more other features, elements, integers, steps, components, or groups thereof.

In response to the difficulties and problems discussed above, a new absorbent article which has a skin contacting surface having a reduced affinity for skin irritants such as those commonly found in biological fluids such as urine and fecal material.

In one aspect, the present invention relates to an absorbent article that includes a bodyside liner that exhibits a reduced affinity for skin irritants. The absorbent article may further exhibit an increasing affinity for such skin irritants in the direction away from the skin contacting surface of the article and into the interior of the article. In such a configuration an increasing skin irritant affinity gradient is provided through at least portions of the article to draw the skin irritants away from the skin of the wearer in use.

The various aspects of the present invention can advantageously provide an absorbent article that may exhibit a substantially reduced concentration of skin irritants from urine and fecal material on their skin-contacting surface in use when compared to conventional absorbent articles. Thus, the skin of wearer may be less susceptible to rashes, abrasion and irritation. As a result, wearer's of the absorbent articles of the different aspects of the present invention may realize a reduction in the incidence of skin irritation and rash.

Brief Description of the Drawings

The invention will be more fully understood and further advantages will become apparent when reference is made to the following detailed description of the invention and the accompanying drawings, in which:

Fig. 1 representatively shows a partially cutaway, top plan view of an absorbent article according to one embodiment of the invention with portions of the article partially cut away to more clearly show the underlying features and with the surface of the article intended to contact the wearer facing the viewer; and

Fig. 2 representatively shows a sectional view of the absorbent article of Fig. 1 taken along line 2-2.

Detailed Description of the Invention

It has been discovered that materials in conventional absorbent articles which are in contact with the skin, such as the bodyside liner in disposable diapers, have typically exhibited a relatively high affinity for skin irritants commonly found in biological fluids such as urine and fecal material. Skin irritants commonly found in biological fluids include proteases, lipases, fatty acids, bile acids and other metabolites which, when exposed to the skin, stimulate the production of pro-inflammatory mediators in the skin.

In general, the degradative enzymes found in biological fluids, such as proteases and lipases, undesirably degrade the stratum corneum components of the skin, which reduce the natural ability of the skin to provide a barrier function. The reduction in the skin's natural barrier function allows for the increased penetration of other irritants in biological fluids, such as fatty acids, into the skin. The degradative action of proteases and lipases on the skin can therefore directly or indirectly lead to skin irritation. The most common form of skin irritation associated with these irritants is diaper dermatitis, or diaper rash. This type of irritant contact dermatitis is most prevalent in infants, but can also occur in adults that wear absorbent articles for incontinence.

Typically, the materials on the bodyfacing surface of conventional absorbent articles exacerbate this problem by binding the skin irritants as the biological fluids pass through the materials. Thus, even after insult, the wearer's skin has typically remained in contact with such irritants for an extended period of time. As a result of this prolonged contact, the wearer's skin has undesirably remained susceptible to rashes, abrasion and irritation.

The absorbent articles of present invention advantageously may exhibit a substantially reduced concentration of skin irritants from biological fluids such as urine and fecal material on their skin-contacting surface in use when compared to conventional absorbent articles. As a result, wearer's of the absorbent articles of the different aspects of the present invention may realize a reduction in the incidence of skin irritation and rash. The following detailed description of the invention will be made in the context of a disposable diaper article that is adapted to be worn by infants about the lower torso. It is readily apparent, however, that the absorbent articles of the present invention would also be suitable for use as other types of absorbent articles, such as feminine care pads, incontinence garments, training pants, and the like. In addition, the invention will be described in the context of its various configurations. It should be appreciated that alternative arrangements of the invention can comprise any combination of such configurations.

Examples of suitable constructions of absorbent articles for use in the present invention are described below and representatively illustrated in Figures 1 and 2. Figure 1 is a representative plan view of an integral absorbent garment article, such as disposable diaper 10, of the present invention in its flat-out, uncontracted state (i.e., with all elastic induced gathering and contraction removed). Portions of the structure are partially cut away to more clearly show the interior construction of diaper 10, and the surface of the diaper 10 which contacts the wearer is facing the viewer. Fig. 2 representatively shows a sectional view of the absorbent article of Fig. 1 taken along line 2 — 2.

With reference to Figs. 1 and 2, the disposable diaper 10 generally defines a front waist section 12, a rear waist section 14, and an intermediate section 16 which interconnects the front and rear waist sections. The front and rear waist sections include the general portions of the article which are constructed to extend substantially over the wearer's front and rear abdominal regions, respectively, during use. The intermediate section of the article includes the general portion of the article that is constructed to extend through the wearer's crotch region between the legs.

The illustrated absorbent article includes a backsheet 20, a liquid permeable bodyside liner 22 positioned in facing relation with the backsheet 20, and an absorbent body 24, such as an absorbent pad, which is located between the backsheet 20 and the bodyside liner 22. The backsheet 20 defines a length and a width which, in the illustrated embodiment, coincide with the length and width of the diaper 10. The absorbent body 24 generally defines a length and width that are less than the length and width of the backsheet 20, respectively. Thus, marginal portions of the diaper 10, such as marginal sections of the backsheet 20, may extend past the terminal edges of the absorbent body 24. In the illustrated embodiments, for example, the backsheet 20 extends

- A - outwardly beyond the terminal marginal edges of the absorbent body 24 to form side margins and end margins of the diaper 10.

The bodyside liner 22 is generally coextensive with the backsheet 20 but may optionally cover an area that is larger or smaller than the area of the backsheet 20, as desired. The backsheet 20 and bodyside liner 22 are intended to face the garment and body of the wearer, respectively, while in use. In the illustrated embodiment, the outwardly facing surface of the bodyside liner 22 provides the skin contacting surface 34 of the diaper 10.

To provide improved fit and to help reduce leakage of biological fluids from the diaper 10, the diaper side margins and end margins may be elasticized with suitable elastic members, such as single or multiple strands of elastic. The elastic strands may be composed of natural or synthetic rubber and may optionally be heat sh nkable or heat elasticizable. For example, as representatively illustrated in Figs. 1 and 2, the diaper 10 may include leg elastics 26 which are constructed to operably gather and shirr the side margins of the diaper 10 to provide elasticized leg bands which can closely fit around the legs of the wearer to reduce leakage and provide improved comfort and appearance. Similarly, waist elastics 28 can be employed to elasticize the end margins of the diaper 10 to provide elasticized waists. The waist elastics are configured to operably gather and shirr the waist sections to provide a resilient, comfortably close fit around the waist of the wearer. In the illustrated embodiments, the elastic members are illustrated in their uncontracted, stretched condition for the purpose of clarity.

The illustrated diaper 10 also includes fastening means, such as hook and loop fasteners 30, employed to secure the diaper on a wearer. Alternatively, other fastening means, such as buttons, pins, snaps, adhesive tape fasteners, cohesives, mushroom-and-loop fasteners, or the like, may be employed.

The diaper 10 may further include other layers between the absorbent body 24 and the bodyside liner 22 or backsheet 20. For example, as representatively illustrated in Figs. 1 and 2, the diaper 10 may include a surge management layer 32 located between the bodyside liner 22 and the absorbent body 24 to prevent pooling of the fluid exudates and further improve the distribution of the fluid exudates within the diaper 10. The diaper 10 may be of various suitable shapes. For example, the diaper may have an overall rectangular shape, T-shape or an approximately hourglass shape. In the shown embodiment, the diaper 10 has a generally l-shape. The diaper 10 further defines a longitudinal direction 36 and a lateral direction 38. Other suitable diaper components which may be incorporated on absorbent articles of the present invention include containment flaps, waist flaps, elastomeric side panels, and the like which are generally known to those skilled in the art.

Examples of diaper configurations suitable for use in connection with the present invention are described in U.S. Patent 4,798,603 issued January 17, 1989, to Meyer et al.; U.S. 5,176,668 issued January 5, 1993, to Bernardin; U.S. 5,176,672 issued January 5, 1993, to Bruemmer et al.; U.S. 5,192,606 issued March 9, 1993, to Proxmire et al., and U.S. 5,509,915 issued April 23, 1996 to Hanson et al., the disclosures of which are herein incorporated by reference.

The various components of the diaper 10 are integrally assembled together employing various types of suitable attachment means, such as adhesive, sonic bonds, thermal bonds or combinations thereof. In the shown embodiment, for example, the bodyside liner 22 and backsheet 20 are assembled to each other and to the absorbent body 24 with lines of adhesive, such as a hot melt, pressure-sensitive adhesive. Similarly, other diaper components, such as the elastic members 26 and 28, fastening members 30, and surge management layer 32 may be assembled into the diaper article by employing the above- identified attachment mechanisms.

The backsheet 20 may suitably be composed of a material which is either liquid permeable or liquid impermeable. It is generally preferred that the backsheet 20 be formed from a material that is substantially impermeable to liquids. For example, a typical backsheet can be manufactured from a thin plastic film or other flexible liquid- impermeable material. For example, the backsheet 20 may be formed from a polyethylene film having a thickness of from about 0.012 millimeter (0.5 mil) to about 0.051 millimeter (2.0 mils). Further, the backsheet 20 may be formed of a woven or nonwoven fibrous web layer which has been totally or partially constructed or treated to impart a desired level of liquid impermeability to selected regions that are adjacent or proximate the absorbent body 24. If it is desired to present the backsheet with a more clothlike feeling, the backsheet 20 may comprise a polyolefin film having a nonwoven web laminated to the outer surface thereof, such as a spunbond web of polyolefin fibers. For example, a stretch-thinned polypropylene film having a thickness of about 0.015 millimeter (0.6 mil) may have thermally laminated thereto a spunbond web of polypropylene fibers, which fibers have a thickness of about 1.5 to 2.5 denier per filament. Such a nonwoven web may have a basis weight of about 17 grams per square meter (0.5 ounce per square yard). Methods of forming such clothlike backsheets are known to those skilled in the art.

Still further, the backsheet 20 may be both liquid impermeable and vapor permeable to enhance the breathability of the absorbent article to reduce the hydration of the wearer's skin during use. Such backsheets may also be constructed to prevent excessive condensation of vapor, such as urine, on the garment facing surface of the backsheet 20 that can undesirably dampen the wearer's clothes. For example, the backsheet 20 may be composed of any suitable materials which either directly provide the above desired levels of liquid impermeability and vapor permeability or, in the alternative, materials which can be modified or treated in some manner to provide such levels.

In a particular embodiment, a microporous film/nonwoven laminate material comprising a spunbond nonwoven material laminated to a microporous film may provide the backsheet 20. The spunbond nonwoven comprises filaments of about 1.8 denier extruded from a copolymer of ethylene with about 3.5 weight percent propylene and defines a basis weight of from about 17 to about 25 grams per square meter. The film comprises a cast coextruded film having calcium carbonate particles therein and defines a basis weight of about 58 grams per square meter prior to stretching. The film is preheated, stretched and annealed to form the micropores and then laminated to the spunbond nonwoven. The resulting microporous film/nonwoven laminate based material has a basis weight of from about 30 to about 60 grams per square meter and a water vapor transmission rate of from about 3000 to about 6000 g/sq.m/24 hr. Examples of such film/nonwoven laminate materials are described in more detail in U.S. Patent No. 5,695,868 issued in the name of McCormack et al., the disclosure of which is hereby incorporated by reference.

The bodyside liner 22, as representatively illustrated in Figs. 1 and 2, suitably presents a bodyfacing or skin contacting surface 34 which is compliant, soft feeling, and nonirritating to the wearer's skin. Further, the bodyside liner 22 may be less hydrophilic than the absorbent body 24, to present a relatively dry surface to the wearer, and may be sufficiently porous to be liquid permeable, permitting liquid to readily penetrate through its thickness. The bodyside liner 22 is suitably employed to help isolate the wearer's skin from liquids held in the absorbent body 24.

A suitable bodyside liner 22 may be manufactured from a wide selection of web materials, such as porous foams, reticulated foams, apertured plastic films, natural fibers (for example, wood or cotton fibers), synthetic fibers (for example, polyester or polypropylene fibers), or a combination of natural and synthetic fibers. Various woven and nonwoven fabrics can also be used for the bodyside liner 22. For example, the bodyside liner may be composed of a meltblown or spunbonded web of polyolefin fibers. The bodyside liner may also be a bonded-carded web composed of natural and/or synthetic fibers. The bodyside liner may be composed of a substantially hydrophobic material, and the hydrophobic material may, optionally, be treated with a surfactant or otherwise processed to impart a desired level of wettability and hydrophilicity. In a particular aspect, the bodyside liner 22 may comprise a nonwoven, spunbond, polypropylene fabric composed of about 2.8-3.2 denier fibers formed into a web having a basis weight of about 22 grams per square meter and a density of about 0.06 gram per cubic centimeter.

The bodyside liner 22 of the different aspects of the present invention also provides a skin contacting surface 34 that, in use, exhibits a reduced concentration of skin irritants commonly found in biological fluids when compared to conventional absorbent articles. The bodyside liner 22 can be constructed in any manner that provides such reduced concentration of skin irritants at the skin contacting surface 34 in use without adversely affecting the skin. For example, the composition of the bodyside liner 22 including the particular polymer chemistry, it's molecular structure, treatment chemistry, density, porosity, permeability and the like can be controlled to provide the bodyside liner 22 with a reduced affinity to the skin irritants commonly found in biological fluids such as urine and fecal material.

In particular, it is desirable that the bodyside liner 22 is constructed such that it does not bind skin irritants but instead allows them to readily pass through the bodyside liner 22 into the interior materials of the absorbent article such as the surge management layer 32 and absorbent body 24. In such a configuration, the amount of skin irritants available to transfer to the skin of the wearer may be substantially reduced thereby resulting in a reduction in the irritation of the wearer's skin.

Desirably, the bodyside liner 22 is constructed such that when insulted with urine there is no increase in its adverse effect on the skin of the wearer. In particular, it is desirable that the adverse effect of the liner on the skin remains substantially unchanged after receiving an insult of urine.

In one aspect, the reduced concentration of skin irritants at the skin contacting surface 34 of the article may be achieved by constructing the bodyside liner 22 of a material having a charge similar to the major irritants in the biological fluids. As a result, the material will have a reduced affinity for the irritants due to electrostatic repulsion that will result in a reduced level of binding between the skin irritants and the material. For example, the majority of the irritating fecal proteases in feces are cationic under physiological conditions. To reduce the level of binding between such proteases and the bodyside liner 22, the bodyside liner 22 may be constructed of a material that has a similar cationic charge. Conversely, a large proportion of the proteins in feces and urine are anionic under physiological conditions. Thus, the application of a fixed negative charge to the material providing the bodyside liner 22 would preclude the binding of a large number of proteins to the material due to electrostatic repulsion. In such a configuration, the selection of proper ratios of both anionic and cationic charges to be applied to the material will afford the opportunity to target the properties of the material for specific irritants. The materials for the bodyside liner 22 may be constructed to inherently provide the appropriate charges or may be modified by the addition of specific treatment compositions to provide the desired charges. For example, an effective amount of an ion-exchange material can be applied to the materials to provide the desired charges. Suitable ion- exchange materials that can be applied to the bodyside liner material include, but are not limited to, chitosan, cellulose-phosphate, dextran-sulfate, dextran-phosphate, charged polysaccharides, charged proteins, and the like and combinations thereof.

Alternatively, the bodyside liner 22 may be constructed of a material that has a relatively low number of binding sites available to bind such skin irritants to provide the reduced concentration of skin irritants at the skin contacting surface 34 of the article. For example, an effective amount of protein may be applied to the material to effectively "tie up" the protein binding sites on the material. As a result of such treatment, a lower level of the proteins found in the biological fluids passing through the materials will bind to the materials thereby resulting in a lower concentration of such irritants on the skin contacting surface 34. Suitable proteins that can be applied to the bodyside liner material include, but are not limited to, sericin, soy protein, wheat protein, gelatin, collagen, casein, milk proteins, keratin, and the like and combinations thereof.

The bodyside liner 22 may otherwise be treated with compositions that can include peptides such as those that result from acid or enzymatic hydrolyzates of proteins from wheat, oat, corn, soy or milk sources; quaternary compounds such as alkyl dimethyl benzyl, quaternary ammonium with alkyl chain lengths ranging from C8 to C18, dimethyl dialkyl quaternary ammonium compounds, trimethyl alkyl quaternary ammonium compounds, as well as compounds that contain betaine groups; and the like and combinations thereof.

The treatment compositions applied to the different materials of the articles of the present invention such as the bodyside liner 22 or surge management layer 34 as discussed below desirably are immobilized on the materials. For example, the specific ingredients added to reduce the concentration of skin irritants on the surface of the article may include a wax or combination of waxes to immobilize the ingredient on the materials thereby reducing their transfer to the skin or further into the other materials of the article. Suitable waxes include animal, vegetable, mineral or silicone based waxes which may be natural or synthetic such as, for example, bayberry wax, beeswax, C30 alkyl dimethicone, candelilla wax, carnauba, ceresin, cetyl esters, esparto, hydrogenated cottonseed oil, hydrogenated jojoba oil, hydrogenated jojoba wax, hydrogenated microcrystalline wax, hydrogenated rice bran wax, japan wax, jojoba butter, jojoba esters, jojoba wax, lanolin wax, microcryustalline wax, mink wax, otan acid wax, motan wax, ouricury wax, ozokerite, paraffin, PEG-6 beeswax, PEG-8 beeswax, rezowax, rice bran wax, shellac wax, spent grain wax, spermaceti wax, steryl dimethicone, synthetic beeswax, synthetic candelilla wax, synthetic carnuba wax, synthetic japan wax, synthetic jojoba wax, synthetic wax, and the like and mixtures thereof.

Other immobilizing agents may include high molecular weight polyethylene glycol such as polyethylene glycols having an average molecular weight of 720 or greater, fatty alcohols such as alcohols having a carbon chain length of C₁₄ -C₃₀, including cetyl alcohol, stearyl alcohol, arachidyl alcohol, and behenyl alcohol and the like and mixtures thereof. The absorbent body 24 of the diaper 10, as representatively illustrated in Figs. 1 and 2, may suitably comprise a matrix of hydrophilic fibers, such as a web of cellulosic fluff, mixed with particles of a high-absorbency material commonly known as superabsorbent material. In a particular embodiment, the absorbent body 24 comprises a matrix of cellulosic fluff, such as wood pulp fluff, and superabsorbent hydrogel-forming particles. The wood pulp fluff may be exchanged with synthetic, polymeric, meltblown fibers or with a combination of meltblown fibers and natural fibers. The superabsorbent particles may be substantially homogeneously mixed with the hydrophilic fibers or may be nonuniformly mixed. Alternatively, the absorbent body 24 may comprise a laminate of fibrous webs and superabsorbent material or other suitable means of maintaining a superabsorbent material in a localized area.

The absorbent body 24 may have any of a number of shapes. For example, the absorbent body may be rectangular, l-shaped, or T-shaped. It is generally preferred that the absorbent body 24 is narrower in the intermediate section than in the front or rear waist sections of the diaper 10. The absorbent body 24 may be provided by a single layer or, in the alternative, may be provided by multiple layers, all of which need not extend the entire length and width of the absorbent body 24. In a particular aspect of the invention, the absorbent body 24 can be generally T-shaped with the laterally extending cross-bar of the "T" generally corresponding to the front waist section 12 of the absorbent article for improved performance.

The size and the absorbent capacity of absorbent body 24 should be compatible with the size of the intended wearer and the liquid loading imparted by the intended use of the absorbent article. Further, the size, density, basis weight and absorbent capacity of the absorbent body 24 can be varied to accommodate wearers ranging from infants through adults. In a particular aspect of the invention, the absorbent body 24 has an absorbent capacity of at least about 300 grams of synthetic urine.

The high-absorbency material can be selected from natural, synthetic, and modified natural polymers and materials. The high-absorbency materials can be inorganic materials, such as silica gels, or organic compounds, such as crosslinked polymers. The term "crosslinked" refers to any means for effectively rendering normally water-soluble materials substantially water insoluble but swellable. Such means can include, for example, physical entanglement, crystalline domains, covalent bonds, ionic complexes and associations, hydrophilic associations such as hydrogen bonding, and hydrophobic associations or Van der Waals forces.

Examples of synthetic, polymeric, high-absorbency materials include the alkali metal and ammonium salts of poly(acrylic acid) and poly(methacrylic acid), poly(acrylamides), poly(vinyl ethers), maleic anhydride copolymers with vinyl ethers and alpha-olefins, poly(vinyl pyrrolidone), poly(vinyl morpholinone), poly(vinyl alcohol), and mixtures and copolymers thereof. Further polymers suitable for use in the absorbent body include natural and modified natural polymers, such as hydrolyzed acrylonitrile-grafted starch, acrylic acid grafted starch, methyl cellulose, carboxymethyl cellulose, hydroxypropyl cellulose, and the natural gums, such as alginates, xanthum gum, locust bean gum, and the like. Mixtures of natural and wholly or partially synthetic absorbent polymers can also be useful in the present invention.

The high absorbency material may be in any of a wide variety of geometric forms. As a general rule, it is preferred that the high absorbency material be in the form of discrete particles. However, the high absorbency material may also be in the form of fibers, flakes, rods, spheres, needles, or the like. In general, the high absorbency material is present in the absorbent body in an amount of from about 5 to about 95 weight percent, desirably in an amount of at least about 30 weight percent, and even more desirably in an amount of at least about 50 weight percent based on a total weight of the absorbent body 24.

An example of high-absorbency material suitable for use in the present invention is

SANWET IM 3900 polymer available from Hoechst Celanese, a business having offices in Portsmouth, Virginia. Other suitable superabsorbents may include W45926 or FAVOR SXM 880 polymer obtained from Stockhausen, a business having offices in Greensboro, North Carolina.

Optionally, a substantially hydrophilic tissue wrapsheet (not illustrated) may be employed to help maintain the integrity of the structure of the absorbent body 24. The tissue wrap sheet is typically placed about the absorbent body over at least the two major facing surfaces thereof and composed of an absorbent cellulosic material, such as creped wadding or a high wet-strength tissue. In one aspect of the invention, the tissue wrap can be configured to provide a wicking layer that helps to rapidly distribute liquid over the mass of absorbent fibers comprising the absorbent body.

Due to the thinness of absorbent body 24 and the high absorbency material within the absorbent body 24, the liquid uptake rates of the absorbent body 24, by itself, may be too low, or may not be adequately sustained over multiple insults of liquid into the absorbent body 24. To improve the overall liquid uptake and air exchange, the diaper of the different aspects of the present invention may further include a porous, liquid-permeable layer of surge management material 34, as representatively illustrated in Figs. 1 and 2. The surge management layer 32 is typically less hydrophilic than the absorbent body 24, and has an operable level of density and basis weight to quickly collect and temporarily hold liquid surges, to transport the liquid from its initial entrance point and to substantially completely release the liquid to other parts of the absorbent body 24. This configuration can help prevent the liquid from pooling and collecting on the portion of the absorbent garment positioned against the wearer's skin, thereby reducing the feeling of wetness by the wearer.

Various woven and nonwoven fabrics can be used to construct the surge management layer 32. For example, the surge management layer 32 may be a layer composed of a meltblown or spunbonded web of synthetic fibers, such as polyolefin fibers. The surge management layer 32 may also be a bonded-carded-web or an airlaid web composed of natural and synthetic fibers. The bonded-carded-web may, for example, be a thermally bonded web that is bonded using low melt binder fibers, powder or adhesive. The webs can optionally include a mixture of different fibers. The surge management layer 32 may be composed of a substantially hydrophobic material, and the hydrophobic material may optionally be treated with a surfactant or otherwise processed to impart a desired level of wettability and hydrophilicity. In a particular embodiment, the surge management layer 32 includes a hydrophobic, nonwoven material having a basis weight of from about 30 to about 120 grams per square meter.

For example, in a particular embodiment, the surge management layer 32 may comprise a bonded-carded-web, nonwoven fabric which includes bicomponent fibers and which defines an overall basis weight of about 83 grams per square meter. The surge management layer 32 in such a configuration can be a homogeneous blend composed of about 60 weight percent polyethylene/polyester (PE/PET), sheath-core bicomponent fibers which have a fiber denier of about 3 d and about 40 weight percent single component polyester fibers which have a fiber denier of about 6 d and which have fiber lengths of from about 3.8 to about 5.08 centimeters.

In the illustrated embodiments, the surge management layer 32 is arranged in a direct, contacting liquid communication with the absorbent body 24. The surge management layer 32 may be operably connected to the bodyside liner 22 with a conventional pattern of adhesive, such as a swirl adhesive pattern. In addition, the surge management layer 32 may be operably connected to the absorbent body 24 with a conventional pattern of adhesive. The amount of adhesive add-on should be sufficient to provide the desired levels of bonding, but should be low enough to avoid excessively restricting the movement of liquid from the bodyside liner 22, through the surge management layer 32 and into the absorbent body 24.

The absorbent body 24 is positioned in liquid communication with surge management layer 32 to receive liquids released from the surge management layer, and to hold and store the liquid. In the shown embodiments, the surge management layer 32 comprises a separate layer which is positioned over another, separate layer comprising the absorbent body 24, thereby forming a dual-layer arrangement. The surge management layer 32 serves to quickly collect and temporarily hold discharged liquids, to transport such liquids from the point of initial contact and spread the liquid to other parts of the surge management layer 32, and then to substantially completely release such liquids into the layer or layers comprising the absorbent body 24.

The surge management layer 32 can be of any desired shape. Suitable shapes include for example, circular, rectangular, triangular, trapezoidal, oblong, dog-boned, hourglass- shaped, or oval. In certain embodiments, for example, the surge management layer can be generally rectangular-shaped. In the illustrated embodiments, the surge management layer 32 is coextensive with the absorbent body 24. Alternatively, the surge management layer 32 may extend over only a part of the absorbent body 24. Where the surge management layer 32 extends only partially along the length of the absorbent body 24, the surge management layer 32 may be selectively positioned anywhere along the absorbent body 24. For example, the surge management layer 32 may function more efficiently when it is offset toward the front waist section 12 of the garment. The surge management layer 32 may also be approximately centered about the longitudinal centerline of the absorbent body 24.

Additional materials suitable for the surge management layer 32 are set forth in U.S. Patent No. 5,486, 166 issued January 23, 1996 in the name of C. Ellis et al. and entitled "FIBROUS NONWOVEN WEB SURGE LAYER FOR PERSONAL CARE ABSORBENT ARTICLES AND THE LIKE"; U.S. Patent No. 5,490,846 issued February 13, 1996 in the name of Ellis et al. and entitled "IMPROVED SURGE MANAGEMENT FIBROUS NONWOVEN WEB FOR PERSONAL CARE ABSORBENT ARTICLES AND THE LIKE"; and U.S. Patent No. 5,364,382 issued November 15, 1994 in the name of Latimer et al. and entitled "ABSORBENT STRUCTURE HAVING IMPROVED FLUID SURGE MANAGEMENT AND PRODUCT INCORPORATING SAME", the disclosures of which are hereby incorporated by reference.

In the different aspects of the present invention, the interior components of the articles such as the surge management layer 32 and the absorbent body 24 may be constructed to have a greater affinity to the skin irritants commonly found in urine and fecal material than the bodyside liner 22. In such a configuration, the surge layer 32 and absorbent body 24 may be configured to absorb, adsorb or draw the skin irritants away from the bodyside liner 22 and, in particular, away from the skin contacting surface 34 of the article for improved performance. For example, the bodyside liner 22 may define an affinity for the skin irritants that is at least 5 percent and desirably at least 10 percent less than the affinity between the skin irritants and surge layer and/or absorbent body 24. Desirably, the different components of the article are configured to provide an increasing skin irritant affinity gradient in the direction perpendicular to and away from the skin contacting surface 34 of the article.

For example, the surge management layer 32 and/or absorbent body 24 may be constructed or otherwise treated such that they bind such skin irritants in use. In one aspect, the increasing irritant affinity gradient may be achieved by constructing the surge management layer 32 and/or absorbent body 24 of materials having a charge opposite to the major irritants in the biological fluids. As a result, the material will have an increased affinity for the irritants due to electrostatic attraction that will result in an increased level of binding between the skin irritants and the materials. For example, the surge layer 32 and/or absorbent body 24 may be constructed of materials that have a fixed negative charge directly opposite of the cationic charge of the majority of the irritating fecal proteases in feces. The fixed negative charge will increase the level of binding between such proteases and the surge layer 32 and absorbent body 24. Conversely, the application of a fixed positive charge to the materials of the surge layer 32 and/or absorbent body 24 would desirably result in the binding of a large number of proteins to the material due to electrostatic attraction. In such a configuration, the selection of proper ratios of both anionic and cationic charges to be applied to the material will afford the opportunity to target the properties of the material for specific irritants.

The materials for the surge layer 32 and/or the absorbent body 24 may be constructed to inherently provide the appropriate charges or may be modified by the addition of specific treatment compositions to provide the desired charges. For example, an effective amount of an ion-exchange material can be applied to the materials to provide the desired charges. Suitable ion-exchange materials that can be applied to the surge layer and/or absorbent body are described above and can include chitosan, cellulose-phosphate, dextran-sulfate, dextran-phosphate, charged polysaccharides, charged proteins, and the like and combinations thereof.

Alternative treatment compositions which may provide the desired increased affinity can include cationic liposomes, cationic lipids, anionic iiposomes, anionic lipids such as phospholipids, clays, and the like and combinations thereof. Additional irritant sequestrants that may be suitable are described in commonly assigned, copending U.S. Provisional Patent Application Serial Number 60/114496 filed December 31 , 1998, in the name of Otts et al. and entitled "LIPID COMPOSITION FOR PREVENTION OF EXOGENOUS ATTACK OF SKIN IRRITANTS FROM BIOLOGICAL FLUIDS", the disclosure of which is hereby incorporated by reference.

The different embodiments of the present invention, as representatively illustrated in Figs. 1 and 2, provide absorbent articles that may advantageously exhibit a reduced concentration of skin irritants from biological fluids such as urine and fecal material on their skin contacting surface in use when compared to conventional absorbent articles. Thus, the skin of the wearers of such articles may be less susceptible to rashes, abrasion and irritation. Having thus described the invention in rather full detail, it will be readily apparent to a person of ordinary skill that various changes and modifications can be made without departing from the spirit of the invention. All of such changes and modifications are contemplated as being within the scope of the present invention as defined by the subjoined claims.

Claims

We claim:

1. An absorbent article for containing biological fluids, said absorbent article comprising: a) a liquid permeable bodyside liner that defines a skin contacting surface; b) a backsheet located in facing relation to said bodyside liner; and c) an absorbent body located between said bodyside liner and said backsheet; wherein a first affinity between said bodyside liner and skin irritants found in said biological fluids is less than a second affinity between said absorbent body and said skin irritants.

2. The absorbent article of claim 1 wherein said first affinity is at least 5 percent less than said second affinity.

3. The absorbent article of claim 1 wherein said skin irritants in said biological fluids are proteases.

4. The absorbent article of claim 1 wherein said skin irritants in said biological fluids are lipases.

5. The absorbent article of claim 1 and further comprising a surge management layer located between said bodyside liner and said absorbent body wherein a third affinity between said surge management layer and said skin irritants is greater than said first affinity.

6. The absorbent article of claim 5 wherein said third affinity is less than said second affinity.

7. The absorbent article of claim 5 wherein said surge management layer includes a treatment composition selected from cationic liposomes, cationic lipids, anionic liposomes, anionic lipids such as phospholipids, clays and combinations thereof.

8. An absorbent article for containing biological fluids, said absorbent article comprising: a) a liquid permeable bodyside liner that defines a skin contacting surface; b) a backsheet located in facing relation to said bodyside liner; c) an absorbent body located between said bodyside liner and said backsheet; and d) an ion exchange material located on said bodyside liner to reduce an affinity between said skin contacting surface of said bodyside liner and skin irritants found in said biological fluids.

9. The absorbent article of claim 8 wherein said ion exchange material is selected from chitosan, cellulose-phosphate, dextran-sulfate, dextran-phosphate, charged polysaccharides, charged proteins and combinations thereof.

10. The absorbent article of claim 8 wherein said skin irritants in said biological fluids are proteases.

1 1. The absorbent article of claim 8 wherein said skin irritants in said biological fluids are lipases.

12. The absorbent article of claim 8 and further comprising a surge management layer located between said bodyside liner and said absorbent body wherein an affinity between said surge management layer and said skin irritants is greater than an affinity between said bodyside liner and said skin irritants.

13. The absorbent article of claim 12 wherein surge management layer includes a second ion exchange material.

14. The absorbent article of claim 13 wherein said second ion exchange material is selected from chitosan, cellulose-phosphate, dextran-sulfate, dextran-phosphate, charged polysaccharides, charged proteins and combinations thereof.

15. The absorbent article of claim 12 wherein said surge management layer includes a treatment composition selected from cationic liposomes, cationic lipids, anionic liposomes, anionic lipids such as phospholipids, clays and combinations thereof.

16. An absorbent article for containing biological fluids, said absorbent article comprising: a) a liquid permeable bodyside liner that defines a skin contacting surface; b) a backsheet located in facing relation to said bodyside liner; c) an absorbent body located between said bodyside liner and said backsheet; and d) a protein located on said bodyside liner to reduce an affinity between said skin contacting surface of said bodyside liner and skin irritants found in said biological fluids.

17. The absorbent article of claim 16 wherein said protein is selected from selected from sericin, soy protein, wheat protein, gelatin, collagen, casein, milk proteins, keratin and combinations thereof.

18. The absorbent article of claim 16 wherein said skin irritants in said biological fluids are proteases.

19. The absorbent article of claim 16 and further comprising a surge management layer located between said bodyside liner and said absorbent body wherein an affinity between said surge management layer and said skin irritants is greater than an affinity between said bodyside liner and said skin irritants.

20. An absorbent article for containing biological fluids, said absorbent article comprising: a) a liquid permeable bodyside liner that defines a skin contacting surface; b) a backsheet located in facing relation to said bodyside liner; c) an absorbent body located between said bodyside liner and said backsheet; and d) a treatment composition located on said bodyside liner to reduce an affinity between said skin contacting surface of said bodyside liner and skin irritants found in said biological fluids.

21. The absorbent article of claim 20 wherein said treatment composition includes a compound selected from peptides, quaternary compounds, compounds that contain betaine groups and combinations thereof.

22. The absorbent article of claim 20 and further comprising a surge management layer located between said bodyside liner and said absorbent body wherein an affinity between said surge management layer and said skin irritants is greater than an affinity between said bodyside liner and said skin irritants.