Winged Napkin Having Cross-Channeling

This application is related to copending and commonly assigned application Ser. No. 078,139, filed July 27, 1987, in the name of Pramod Mavinkurve, having attorney docket number (PPC-297), entitled "Fluid Barrier Seal for Sanitary Napkins Having Undergarment Protecting Flaps".

This invention relates to protective, absorbent liners for undergarments, and more particularly, to improved sanitary protection for the transverse ends of napkins having undergarment protecting flaps.

Sanitary napkins have customarily included a central absorbent element having a body facing side, a garment facing side, longitudinally extending sides and transverse ends, In the past, these products sometimes failed to provide proper protection because the edges of the crotch of the panty, to which these products are adhered, tended to enfold onto the body facing side of the napkin. This condition can cause the panty to be stained with body fluid, either emanating from the napkin or exuding from the body of the wearer.

In order to overcome this deficiency, several of the more recent napkin designs have included flaps extending along the longitudinal sides of the absorbent element. Mattingly, U.S. Pat. No. 4,608,047, for example, is directed to such a sanitary napkin having flaps extending from a central absorbent. This product is adhesively attached to an inner crotch portion of a user's undergarment and its side flaps are then folded onto an outer surface of the crotch portion to protect the garment. McNair, U.S. Pat. No. 4,285,343, is also directed to a napkin having flaps for folding over the outer surface of the wearer's garment. Both of these patents provide for embodiments that include absorbent pads in their flaps, thereby inviting the transmission of body fluid from the central absorbent element While sanitary napkins with wings or flaps have been designed to provide superior protection from fluid staining from the sides of the napkin, staining can often occur due to the transmission of body fluid from the transverse ends of these napkins Accordingly, there is a need for limiting or delaying the transmission of fluid to the ends of these napkin designs so as to minimize "product failure".

In prior art sanitary napkins not having flaps extending laterally from their absorbent element, the techniques of indenting or compressing a portion of the central absorbent for assorted reasons has been suggested.

Matthews et al. U.S. Pat. No. 4,397,644, is directed to a sanitary napkin having an additional comfort layer disposed between the principle absorbent and the fluid permeable cover. This comfort component is integrated with the cover to provide intimate contact and densification to localized regions of the product. These densified regions create fluid transfer routes, whereby viscous body fluids can be directed into the principle absorbent. The densification of the additional absorbent component of Matthews, however, is designed for transferring, rather than delaying the transmission, of body fluid.

Mogor, U.S. Pat. No. 3,575,174, is directed to a sanitary napkin which is maintained in a shaped configuration by deep embossed channels impressed through the cover and into the core of the napkin to compression bond the two components together The deep embossed channels are positioned near the lateral end edges on the top surface of the napkin and at the rearward end on the bottom surface of the napkin. The embossed channels are designed to shape the sanitary napkin for fit against the body of the wearer. This design is not intended to create delayed absorbency, nor is there a teaching for absorbent wings that provide protection by wrapping around the outer portion of the panty.

Joa, U.S. Pat. No. 2,721,554 is directed to a sanitary napkin having a pair of absorbent pads with a liquid-permeable tissue interposed between the pads for regulating the flow of liquid between the two absorbent elements. The patent teaches the use of a compression molding of the two pad elements near the transverse ends of the napkin for adhesion of the pads to each other through pressure knitting of their fibers at these localized zones. The invention further directs that one of the pads should be shorter than the other so that the thickness of the pad at its ends may be reduced without undue compression of the pulp. This patent, therefore, is not directed to delayed or compartmentalized absorbency, but rather, employs compressed areas of the pulp as a means for joining two pulp portions together

Hirsch, U.S. Pat. No. 2,154,332 is directed to a sanitary utility pad having a petal construction with a pocket or depression for initially catching any fluid to be absorbed so that it will not run off the pad. The pocket of this invention appears to be a cut out of the central absorbent, rather than being a compressed portion of the pulp. The object of this device is to provide sufficient time for the filler or inner portion of the absorbent to absorb the body fluid before it runs off the fluid pervious surface. There is no teaching in this patent, however, for delayed absorption through the napkin by the extremities of the central absorbent.

Whitehead, U.S. Design Pat. Nos. 247,369, 247,370, 247,371, 247,372 are directed to ornamental designs for a contoured sanitary napkin, illustrating patterns embossed on the body-facing side of the napkin. These designs, however, do not appear to be directed to delayed absorbency and are primarily directed to aesthetic appearance.

German Patent 959,814, Mar. 14, 1957, is directed to a diaper configuration with a notched central absorbent area having a water-tight cover on its body facing side and perforations in the bottom of the notched areas for transmitting fluid to the product's absorbent tissue.

Canadian Pat. No. 884,608 (issued Nov. 2, 1971 to Yvon G. Levesque) describes a product and method for inhibiting liquid leakage at the edges of an absorbent product which contains a continuous hydrophobic gas and vapor permeable open-pore zone about the edge margin of the product.

While at least one of the above-mentioned patents, Hirsch, suggests preventing leakage of body fluid from the transverse ends of a sanitary napkin, none of these references is directed to sanitary napkins having panty-protecting flaps. Accordingly, if one were to compartmentalize the transverse ends of a central absorbent of a typical prior art napkin, body fluid would merely be directed to the longitudinal sides of the napkin which may have relatively little absorbing capacity, or none at all.

Accordingly, there is a need for a sanitary napkin, having absorbent flap portions, that provides a means for preventing the transmission of body fluid from its transverse ends. There is also a need for a compartmentalized sanitary napkin having reserve absorbent capacity on its transverse ends and longitudinal sides

A sanitary napkin is provided having a fluid retarding means disposed transversely across its absorbent element for inhibiting the transmission of body fluid from a central portion of the absorbent element to one of the element's transverse ends. In order to effect additional protection from staining at the ends of the sanitary napkin of this invention, hydrophobic material may be located at the transverse ends of the absorbent pad. The hydrophobic material acts in combination with the cross channels to provide additional protection against failure at the ends of the pad. The cross channels resist or delay the absorption of fluid in the ends of the pad. The hydrophobic material provides a fluid repellant barrier, which prevents the fluid from passing into the ends of the pad and, by containing the fluid, prevents it from leaching out to the wearer's panty. The design is especially suited to winged napkin configurations, especially those that have absorbent tissue in their flaps or wings. The preferred configuration for this invention includes two channels which are placed across the width of the absorbent pad such that the ends of each channel are within the portion of the napkin protected by the flaps. The channels preferably represent compressed portions of the absorbent element which allow the transmission of body fluid after a central portion of the absorbent element is saturated. This "delayed absorbency" represents an improvement, whereby a greater portion of the menstrual fluid is confined to the center of the winged sanitary napkin and the transverse ends of the napkin act predominantly as reserve capacity

The channels of this invention also provide a better fitting napkin, since they represent a point at which the pad may be readily bent to conform to the body of the wearer. The ends of the preferred napkin can raise up with less resistance than a conventional napkin and, thus, provide a closer fit. This improved fit, particularly at the pad ends, leads to improved protection.

Thus, a winged sanitary napkin is provided having means for preventing the transmission of body fluid from its transverse ends. This napkin also provides for compartmentalized sanitary protection by including reserve absorbent capacity within the transverse ends as well as along the longitudinal sides of the central absorbent.

It is, therefore, an object of this invention to provide a winged sanitary napkin that provides improved protection from staining.

It is another object of this invention to provide a sanitary napkin that creates absorbent reserve areas at the transverse ends of the napkin that absorb body fluid after a central portion of the napkin has been saturated.

It is still another object of this invention to provide a sanitary napkin having multiple absorbent compartments designed to trap body fluid which is transferred along the body fluid pervious surface of the napkin.

With these and other objects in view, which will become apparent to one skilled in the art as the description proceeds, this invention resides in the novel construction, combination, arrangement of parts and methods substantially as hereinafter described and more particularly defined in the attached claims.

The accompanying drawings illustrate a complete embodiment of the invention according to the best mode for the best practical application of the principles thereof, and in which:

FIG. 1: is a planar view of the body-facing side of a sanitary napkin embodiment of this invention illustrating the fluid retarding channels disposed across the absorbent element;

FIG. 2: is a planar view of the sanitary napkin embodiment of FIG. 1 illustrating the undergarment-facing side and adhesive strips;

FIG. 3: is a partial, transverse, cross-sectional view of the napkin of FIG. 1, taken through line 3--3, illustrating the fluid retarding channel of this embodiment.

FIG. 4: is a transverse, cross-sectional view of an alternative fluid retarding means comprising a treated portion of the central absorbent element.

FIG. 5: is a planar view of the body-facing side of an alternative preferred sanitary napkin embodiment illustrating fluid barrier seal means disposed between the flaps and the absorbent element of the napkin.

FIG. 6: is a planar view of the body-facing side of an alternative preferred sanitary napkin embodiment illustrating fluid repellent means disposed along the transverse edges of the absorbent element of the napkin

FIG. 7: is a longitudinal, cross-sectional view of the napkin of FIG. 6, taken through line 7--7 illustrating the fluid repellent means of this embodiment.

In accordance with the teachings of this invention, an improved sanitary napkin is provided for minimizing panty staining due to leakage from the napkins transverse ends. The sanitary napkin of this invention includes an absorbent element and flaps extending laterally from this element An important feature of the napkin is a fluid retarding means disposed transversely across the absorbent pad for inhibiting the transmission of body fluid from a central portion of the pad to one of the transverse ends of the napkin. The invention is designed to improve the performance of a preferred winged sanitary napkin by minimizing the potential for failure at the transverse ends.

Referring now to FIGS. 1-3, which illustrate in planar and cross-sectional views, a preferred sanitary napkin 100, embodying the teachings of this invention. The sanitary napkin 100 comprises an absorbent element having longitudinally extending sides 60 and transverse ends 50. The napkin 100 further includes flaps 16 and 18 extending laterally from each of the longitudinal sides 60 of the absorbent element. An important aspect of this invention is a fluid retarding means which is disposed transversely across the absorbent element for inhibiting the transmission of body fluid from a central portion 20 of the absorbent element to one of the transverse ends 50. The fluid retarding means of this invention preferably comprises at least two compressed channels 24 and 26 of the absorbent element

Generally the compressed portions 24 and 26 of the napkin 100 are designed to divide the absorbent element into central component 20 and two end components 14 and 22. The central component 20, as illustrated in FIG. 1, preferably has a larger surface area than the end components 14 and 22. It is also desirable that the preferred compressed portions be disposed along curvilinear paths as shown by FIG. 1. Although this construction is not a requirement, it maximizes the area of the central component 20 while permitting lateral transfer of fluid from the absorbent element into the flaps 16 and 18 In a preferred embodiment, flaps 16 and 18 comprise absorbent material, such as an absorbent tissue, enabling the flaps 16 and 18 to also absorb body fluid which may be transferred from the central portion 20 of the absorbent element.

Although the fluid retarding means preferably comprises mechanically compressed portions of the pulp of the central absorbent element, body fluid transfer could also be inhibited by chemically treating the pulp with standard repellant materials, as illustrated by FIG. 4. These may include, for example, emulsions of fluorocarbon, wax or silicone.

This invention contemplates, as a preferred embodiment illustrated in FIG. 5, employing a fluid barrier seal 65 and compressed areas 24 and 26 of the napkin for regulating the flow of body fluid from the central portion 20 of the napkin 100. As used herein, a "fluid barrier seal" refers to any sealing means which will prevent body fluid from transferring either by wicking or seeping across the seal. In the preferred embodiment depicted in FIG. 5, the napkin 100 comprises body fluid sealing means 65 disposed between the absorbent element and the flaps 16 and 18 for preventing the transmission of body fluid from the absorbent element into the flaps 16 and 18. In such a design, the flaps 16 and 18 would preferentially be use>only as backup compartments to absorb fluid from occasional gushing, fluid that has been smeared to the body, or fluid exuding from leaky, misplaced napkins. When combined with the novel channels of this invention, the flaps 16 and 18, including a body fluid barrier seal 65, would minimize the incidence of napkin failure through the longitudinal sides 60, and would concentrate the body fluid within the central portion 20 of the absorbent area. Accordingly, this would direct the flow of body fluid into the two end components 14 and 22 at an earlier time than without a seal 65.

Without the fluid barrier seal 65 between the central absorbent 20 and the flaps 16 and 18, body fluids travel through the molded pulp of the absorbent element and into the bottom tissue of the napkin. This bottom tissue includes fine capillaries that enable the body fluid to travel at a faster rate and spread through the tissue into the flaps 16 and 18. In such a design, a molded pulp within the central portion 20 of the absorbent element and the tissue within the flap portions 16 and 18 become one absorbent system. The end components 14 and 22 would then be available to accept the overflow of body fluid from this one absorbent system.

When fluid seal 65 is provided, it is preferably disposed along the entire boundary between the absorbent element and the flaps 16 and 18. In addition to this sealing means 65, the sanitary napkin 100 may further comprise a fluid tight seal 10 around the entire periphery of the napkin 100, including the flaps 16 and 18. The flaps 16 and 18 are preferably sealed around their perimeter, and generally can be selected to comprise a width that is greater than the adjoining length of the central compartment 20. As used herein, the "width" of the flaps 16 and 18 refers to the dimension of the flaps 16 and 18 that borders the absorbent element of the napkin 100.

The preferred compressed portions 24 and 26 of the napkin 100, representing the fluid retarding means of this invention, preferably have end points which lie on a pair of junction lines between the absorbent element and the flaps 16 and 18. Body fluid absorbed by the central component 20 of this embodiment is transmitted into the flaps 16 and 18 in the absence of a fluid barrier seal 65.

It is further anticipated that the sanitary napkin 100 can be folded along the compressed portions 24 and 26 to provide a better fit for the napkin, preferably to provide a concave configuration for the body side surface of the napkin 100. This "better fit" capability is provided because the channels or compressed areas 24 and 26 provide a point at which the napkin 100 may be readily bent. The compressed areas 24 and 26 provide hinges so that the ends of the napkin can raise up with less resistance, enabling the napkin to fit snug against the body, which corresponds generally to improved protection.

FIG. 6 illustrates a sanitary napkin 200 having an elongated absorbent element 220 which contains central absorbent portion 214. Fluid resisting means, or transverse channels 224 and 226, aid in containing body fluid in the central portion of absorbent element 220 which contains central absorbent portion 214. Napkin 200 also contains side panels 216 and 218 adjacent central absorbent element 214. Side panels 216 and 218 may be wrapped around the crotch of a wearer's undergarment in use so as to protect the undergarment from receiving menstrual fluid overflowing central absorbent portion 214. Once the central portion of absorbent element 214 becomes saturated, the reserve capacity of the transverse ends of absorbent element 220 may be used for absorbing body fluid. In order to prevent the body fluid from leaking from the transverse ends, fluid repellant means 270 and 280 are placed around the ends.

Fluid repellant means 270 and 280 may be composed of hydrophobic fiber such as polyester or an absorbent material, such as pulp, which has been treated to render it repellant or nonabsorbent. Preferably, the fluid repellant means is a fibrous material which has been treated to render it fluid repellant, due to the ability of a fibrous material to maintain intimate contact with the absorbent medium. Such intimate contact is important in order to maintain the integrity of the pad. Without such integrity, the pad would develop gaps and, therefore, leaks, rendering the fluid repellant means ineffective. Intimate contact between the fibers of the fluid repellant barriers and the absorbent element aids in maintaining the shape and structure of the sanitary napkin, providing a uniform surface, breathability and eliminating void space. Using fluid repellant fiber enhances comfort by providing a uniform surface. It may be made to appear similar to absorbent fiber, or it may be highlighted by dye in order to render its presence apparent to the user. Fibrous material such as pulp, cotton, rayon or the like may be treated with fluid repellant solutions to render it repellant to body fluid. Normally fluid repellant fibers such as polyester or bicomponent fibers such as polyethylene/polyester fibers, may also be used as fluid repellant means.

The fluid repellant means may also be made of a polymeric foam such as urethane, styrene, or a polyalkylene such as polypropylene or polyethylene; or the like. The foam should be fairly resilient and flexible, so as to be comfortable as possible for the user.

A sanitary napkin can be made in accordance with the teachings of this invention having a perforated, coextruded film cover composed of polyethylene and ethyl vinylacetate, an absorbent element composed of ground wood pulp and fluid repellant ends containing ground wood pulp which has been treated with Aquapel Emulsion 260XC, an alkylketene preparation available from Hercules Inc. The fluid repellant composition may be applied to the absorbent element by mixing with pulp slurry and/or by spraying or by other means known to those skilled in the art. Cellulosic tissue, an absorbent medium, is placed in the side panels. The pulp may also be treated with fluorocarbon solutions, waxes, silicones, adhesive sprays or the like in order to render them fluid repellant. The fluid-impervious garment-facing surface may be made of coextruded polyethylene and ethylvinyl acetate. A fluid barrier seal is made along the perimeter of the napkin and, preferably, around the perimeter of the absorbent element, by thermally sealing the ethylvinylacetate present in the cover and barrier. The napkin may be attached to the crotch of an undergarment by three lines of Fuller HM 1940W adhesive, a hot melt pressure sensitive adhesive, available from H. P. Fuller of Minnesota, coated on the barrier. A tape tab coated with adhesive, preferably that set forth in copending U.S. patent application Ser. No. 089,781, filed Aug. 26, 1987 entitled "Sanitary Napkin", can be fixed on the proximal edge of at least one of the side panels for attaching the side panels on the side of the undergarment opposing the body-facing side.

The absorbent element of this invention should be made of soft, comfortable material. Preferably this element is cut into an "hour glass shape" as illustrated in FIGS. 1 and 2. Adequate absorbency may be built into the core of the absorbent without adding bulk by adding superabsorbent materials, now known, which have the properties of high-liquid retention, for example, cross-linked acrylate polymers. The absorbent element should retain fluid well without allowing it to squeeze out and re-wet the wearer.

Generally, the absorbent element should be about 4-10 inches in length, preferably about 6-9 inches. As described in FIG. 3, the absorbent element comprises an absorbent core 100 which preferably is made of loosely associated absorbent hydrophilic materials such as cellulose fibers, wood pulp, regenerated cellulose or cotton fiber, and/or other materials generally known in the art. Such fibers may be chemically or physically modified and the core may include such fibers in combination with other materials, both natural and synthetic, including other fibers, foams, polymers, and the like. However, for the preferred embodiment of this invention, wood pulp is the material of choice because of its availability and inexpensive cost.

As is customary in the art, a body fluid pervious surface 42 covers the side of the napkin to be worn against the body of the user. Surface 42 can be a resilient, relatively non-absorbing , fluid pervious material. This material is provided for comfort and conformability and directs fluid to the underlying absorbent core, for example, wood pulp, which retains such fluid. This surface 42 may be woven or non-woven material pervious to body fluid contacting its surface, and should be soft and easily permeated by body fluids. Preferably, this surface 42 should be made of a material which allows the passage of fluid without wicking it appreciably in its horizontal plane. Furthermore, it should retain little or no fluid in its structure to provide a relatively dry surface next to the skin. Generally, the fluid permeable surface 42 is a single, rectangular sheet of material having a width sufficient to cover the body-facing side of the absorbent element. Preferably the fluid pervious surface 42 is longer than the core 46 so as to form end tabs, which may be sealed with another pervious or non-pervious layer to fully enclose the core 46. The fluid pervious surface 42 is preferably made of fibers or filaments of thermoplastic hydrophobic polymers such as polyethylene or polypropylene.

Underlying the core 46 of the absorbent element can be another layer of absorbent material (not shown) to provide additional resiliency to the product. This layer may be substantially wider than the core 46 of the central absorbent and may extend into the flaps 16 and 18. The absorbent layer may comprise a thin, absorbent layer of material such as a tissue, fabric or the like, made of cellulosic fibers. Because such material is provided as a safety measure, and is only required to contain fluid which escapes from the side edges of absorbent core 46, it need not be very absorbent at all and, in fact, may be comprised of any capillary or cellular system including hydrophobic material. However, the preferred material is a hydrophilic fabric comprised of celluosic fibers such as wood pulp tissue or other suitable hydrophilic woven or nonwoven material. It should also be understood that while such materials preferably extend into the flaps 16 and 18 for the full distance from the absorbent element, if desired, this absorbent tissue may extend only a short distance from absorbent element.

The sanitary napkin 100 of this invention further includes a body fluid impervious surface 44 on the undergarment-facing side of the absorbent element. The impervious surface may allow passage of air and moisture vapor while substantially blocking the passage of liquid to the outer surface. The impervious surface 44 may be heat sealed or fastened by way of adhesives to the core 46 or to the underlying layer of absorbent material and preferably extends over wing areas 16 and 18. The impervious surface 44 may comprise any thin, flexible, body fluid impermeable material such as a polymeric film of, for example, polyethylene or polypropylene or cellophane, or even a normally fluid pervious material that has been treated to be impervious such as impregnated fluid repellent paper or nonwoven fabric.

Referring now to FIG. 2, the attachment adhesive elements of this invention can be made of any known pressure-sensitive adhesive material. As used herein, the term "pressure-sensitive" refers to any releasable adhesive or releasable tenacious means. Adhesive compositions suitable for sanitary napkins include, for example, the water-based pressure-sensitive adhesives such as acrylate adhesives, e.g. vinyl acetate-2 ethyl hexyl acetate copolymer which is generally combined with tackifiers such as, for example, ethylene amine. Alternatively, the adhesive may comprise the rapid setting thermoplastic "hot melt" adhesives. The adhesive elements may also comprise a two-sided adhesive tape. It is also anticipated that adhesives based on an elastomer selected from natural or synthetic rubbers could be used. Several adhesive placements are deemed adequate for adhering the preferred napkin 100 to an undergarment and for securing the flaps. See Mattingly, U.S. Pat. No. 4,608,047 and McNair, U.S. Pat. No. 4,285,343, which teachings are herein incorporated by reference. It will be understood that alternative shapes for these adhesives, for examples, lines, squares, circles, etc., may also be employed.

FIG. 2 illustrates an embodiment having an adhesive element 37 with release strip 12 affixed to flap 18 of the napkin. The adhesive strip 37 is the means for fixing the flaps 16 and 18 to the outer crotch portion of the undergarment. In this embodiment, the flaps overlap each other as they are wrapped around the outer crotch portion of the undergarment and the adhesive element 37 is positioned to hold the napkin in place by adhering one flap to the other.

Alternatively, each of the flaps 16 and 18 may have adhesive means disposed on their surfaces for attaching the napkin 100 to the inner crotch portion of an undergarment. See McNair, U.S. Pat. No. 4,285,343. In this embodiment, the flaps are folded upon an outer portion of the undergarment and secured using their own pressure-sensitive adhesive means. The napkin may also employ adhesive 35 lines for attaching the central absorbent to the inner crotch portion of the undergarment.

From the foregoing it can be realized that this invention provides a improved winged sanitary napkin having a central absorbent component, end components that have delayed action absorbency, and fluid repellant means which aid in the prevention of end failure. This is a unique improvement over the current state of the art napkins having flaps and a single central absorbent pad, since failure through the transverse ends of the napkin can be minimized. Although various embodiments have been illustrated, this was for the purpose of describing, but not limiting the invention. Various modifications, which will become apparent to one skilled in the art, are within the scope of this invention described in the attached claims.