US3871378A

US3871378A - Absorbent bandage

Info

Publication number: US3871378A
Application number: US343774A
Authority: US
Inventors: Robert C Duncan; Grace L Smith
Original assignee: Procter and Gamble Co
Current assignee: Procter and Gamble Co
Priority date: 1973-03-22
Filing date: 1973-03-22
Publication date: 1975-03-18
Anticipated expiration: 1992-03-18
Also published as: CH568754A5; PH11356A; FR2222069B1; ES201614U; CA1064202A; ES201614Y; DE2413039A1; NO741017L; NO135455C; BE812621A; NL7403807A; IT1018633B; JPS5026389A; NO135455B; FR2222069A1; IE39087L; DK136176C; BR7402279D0; IE39087B1; ATA231074A

Abstract

An absorbent bandage or sanitary napkin suitable for use as either a catamenial or an incontinent device adapted to conform more effectively to the shape of the body in the area of the female genitalia whether the wearer is in a standing, sitting or lying position, said napkin being so constructed as to assume an upwardly concave conformation in both the transverse and the longitudinal directions when worn. The absorbent pad of a preferred embodiment of a sanitary napkin of the present invention is comprised of a basically hydrophobic, non-woven, needle-punched polyester two sheet of relatively low density in contiguous association with one or more absorbent core layers of basically hydrophilic bleached wood pulp fibers airlaid and compressed into a continuous web of relatively high density. The interface thus formed between the top sheet and the absorbent core provides a gradient of diminishing capillary size between the top sheet which has a relatively large pore structure and the absorbent core which has a relatively small pore structure, which gradient promotes rapid transmission of body fluids into the absorbent core material, thereby minimizing lateral spreading of body fluids deposited on the top sheet. This permits more effective utilization of the absorptive capacity of the absorbent core material, and prevents migration of body fluids absorbed by the absorbent core material back through the surface of the topsheet, thereby retaining absorbed body fluids within an envelope formed by the waterproof backing sheet adjacent its lowermost surface and the top sheet which overwraps its uppermost surface and its edge portions.

Description

United States Patent [191 Duncan et al.

[ Mar. 18, 1975 ABSORBENT BANDAGE [75] Inventors: Robert C. Duncan, Wyoming; Grace L. Smith, Cincinnati, both of Ohio [73] Assignee: The Procter & Gamble Company, Cincinnati, Ohio 221 Filed: Mar. 22, 1973 21 Appl. No.: 343,774

[52] U.S. Cl. 128/290 [51] Int. Cl. A6lf 13/16 [58] Field of Search 128/290 R, 290 W, 290 P,

[56] References Cited UNITED STATES PATENTS 2,964,039 12/1960 Johnson, Jr. et a1 128/290 R 3,575,174 4/1971 Mogor 128/290 R 3,621,847 11/1971 Roberson 128/290 R 3,736,931 6/1973 Glassman 128/290 R Primary ExaminerLucie H. Laudenslager Attorney, Agent, or Firm-E. Kelly Linman; Frederick H. Braun; John V. Gorman [5 7] ABSTRACT An absorbent bandage or sanitary napkin suitable for use as either a catamenial or an incontinent device adapted to conform more effectively to the shape of the body in the area of the female genitalia whether the wearer is in a standing, sitting or lying position, said napkin being so constructed as to assume an upwardly concave conformation in both the transverse and the longitudinal directions when worn. The absorbent pad of a preferred embodiment of a sanitary napkin of the present invention is comprised of a basically hydrophobic, non-woven, needle-punched polyester two sheet of relatively low density in contiguous association with one or more absorbent core layers of basically hydrophilic bleached wood pulp fibers airlaid and compressed into a continuous web of relatively high density. The interface thus formed between the top sheet and the absorbent core provides a gradient of diminishing capillary size between the top sheet which has a relatively large pore structure and the absorbent core which has a relatively small pore structure, which gradient promotes rapid transmission of body fluids into the absorbent core material, thereby minimizing lateral spreading of body fluids deposited on the top sheet. This permits more effective utilization of the absorptive capacity of the absorbent core material, and prevents migration of body fluids absorbed by the absorbent core material back through the surface of the topsheet, thereby retaining absorbed body fluids within an envelope formed by the waterproof backing sheet adjacent its lowermost surface and the top sheet which overwraps its uppermost surface and its edge portions.

18 Claims, 6 Drawing Figures PATEN MAR 1 8 i975 SHEET 1 UF 2 Fig. 3

ABSORBENT BANDAGE FIELD OF THE INVENTION This invention relates to absorbent bandages, particularly sanitary napkins, and more particularly to sanitary napkins or other structures suitable for use either as a catamenial or an incontinent device. In a preferred embodiment, the napkin will assume an upwardly concave conformation when worn. In another preferred embodiment, the napkin includes a forward extension of the absorbent pad which is unrestrained and is hence free to bend relative to the main body of the absorbent pad to form a seal against the frontal portions of the body. In addition, this invention has particular relation to absorbent bandages, particularly sanitary napkins, wherein the absorbent core is comprised preferably of a multiplicity of layers of relatively dense, basically hydrophilic, compressed airfelt in contiguous association with a waterproof backing sheet on its lowermost surface and overwrapped on its uppermost surface and edge portions by a top sheet of basically hydrophobic, non-woven, relatively low density material to produce a favorable density gradient between the top sheet and the absorbent core material. This in turn promotes rapid transmission of menses or other discharged body exudate into the absorbent core material, minimizes lateral spreading of such body fluids on the topsheet, utilizes more effectively the absorptive capacity of the absorbent core material, and retains body fluids absorbed by the absorbent core material within an envelope formed by the waterproof backing sheet and the top sheet.

BACKGROUND OF THE INVENTION Absorbent pads, and especially sanitary napkins, have been made in a variety of shapes and have incorporated numerous structural features in attempts to provide an article of such nature which fulfills its absorbing function and which is also comfortable and non-chafing when worn.

Sanitary napkins which are in common use generally have the shape of a rectangular parallelepiped which is enclosed by a fluid permeable cover which is elongated at both ends of the napkin to provide attachment tabs intended to be attached to the clasps of a sanitary belt at the front and rear of the wearer. Tensional forces induced uniformly along the leading edge of the absorbent core by attachment of such a napkin to a sanitary belt bend'the ends of the sanitary napkin upwardly in the longitudinal direction, while lateral compressional forces in conjunction with the uniformly induced tensional forces, particularly in the region rearward of the vulva between the buttocks, bend the sides of the napkin downwardly so that it forms a downwardly concave or an inverted U-shape in order to conform to the contours of the female pubic arch. Thus, body fluids deposited on the upper surface of the downwardly concave transverse section have a natural tendency, due to the shape of the structure, to run downwardly toward the lateral edges of the pad, thereby promoting run-off and soiling of undergarments. Such external forces applied to the napkin also tend to produce irregular surfaces in the napkin, particularly along the uppermost portions of its lateral edges, which generally take the form of troughs, folds, triangles ridges, flutes, etc., thereby preventing intimate contact between the napkin and the body of the wearer in the area of the vulva where snug fit is most important.

Such downwardly concave curvature also promotes slippage of such a napkin and smearing. Slippage is relative movement between the napkin and the trunk of the body of the wearer; smearing is the soiling of parts of the body of the wearer adjacent the labia majora, usually as a result of slippage.

Since most prior art sanitary napkins have absorbent pads which are of uniform cross section at any point along their longitudinal axis, greater tensional forces are required to cause such a pad to assume an upwardly concave configuration in the longitudinal direction to conform to the female anatomy, thereby producing greater discomfort to the wearer. This is primarily due to deformation of the external female organs coming in contact with the uppermost surface of the pad. Such rectangular style napkins are also uncomfortable to the wearer from the standpoint of chafing, due to the fact that the lateral edges of the napkin contact the inner portions of the thighs at a point where considerable movement occurs relative to the trunk of the body, and hence movement also occurs relative to the lateral edge portions ofthe napkin. Movement of the thighs relative to the lateral edges of the napkin causes irritating frictional forces to be exerted against the inner portions of the thighs, and at the same time tends to promote runoff from the lateral edge portions of the napkin due to the fact that a seal is not maintained along such lateral edge portions of the napkin in the area of the body where body fluids are usually deposited.

In an attempt to eliminate the above problems, sanitary napkins have been made from conventional overwrap and core materials with rearward portions of reduced size to'conform more nearly to the configuration of the female anatomy in the area of the buttocks. Such a reduction in size has usually been accomplished by reducing the amount of absorbent material contained in the rearward end of the napkin either by cutting away portions of the napkin along the sides of the rearward portion or by forming the napkin initially with less absorbent material in the rearward portion. Such procedures have generally been satisfactory from the standpoint of improved comfort. However, considerable sacriflce is made with respect to providing an effective absorbing medium for the overall performance of such a sanitary napkin due to the fact that very poor fluid transfer characteristics are inherent in prior art sanitary napkins, regardless of shape or size. This is due to the fact that the fluid pervious overwrap material used in such napkins is typically more dense than the core material, thus providing a gradient of increasing capillary size in the direction of the core material which tends to inhibit fluid transfer from the top sheet to the absorbent core material.

An alternative approach to forming a sanitary napkin with a reduced size in its'rearward portion has been to provide a sanitary napkin having a preformed arcuate configuration in the longitudinal direction, thereby eliminating or at least greatly reducing the tensional forces required to bend an initially flat sanitary napkin into the desired in use configuration. Preforming a sanitary napkin into an arcuate configuration eliminates the transverse ridges and troughs which are normally formed in the uppermost surface when a normally flat sanitary napkin is subjected to tension to force it to conform to the female anatomy by attachment to a sanitary belt. Elimination of these ridges and troughs is important because they encourage the flow of body fluids deposited on the top sheet to the sides of the napkin. This results in the soiling of undergarments and consequent in-use failure of the napkin substantially before the full utilization of its absorptive capacity. However, for a sanitary napkin to obtain a preformed, arcuate configuration, it has usually been necessary to build in stabilizing forces within the napkin, itself. This is normally done by providing shrinkable elements strategically placed within the sanitary napkin or by having thermoplastic or thermosetting moldable elements strategically distributed throughout the napkin which, upon activation by heat or chemical treatment, are effective to draw the sanitary napkin into the desired arcuate configuration, or which, by placement into suitable molding forms, are effective to mold the sanitary napkin into its desired configuration. Such processes, however, are usually expensive, and sometimes have the effect of substantially reducing the effective absorption characteristics of the absorbent core, particularly where such napkins employ water insoluble binders. Lack of absorptive capacity reduces potential wearing time and increases the possibility of in-use failure. In addition, such products are usually stiff and, therefore, must be shaped precisely to fit the body to be comfortable.

In absorbent bandages, and particularly in sanitary napkins, it is extremely desirable that the construction be such that any discharged body fluids which strike the surface thereof be carried to the interior of the pad as rapidly as possible to be distributed evenly throughout the interior absorbent portion and retained therein. If this is accomplished effectively, excessive spreading of the fluid on the surface and eventually over the edges of the pad is avoided.

In prior art sanitary napkins, the absorbent core material is usually overwrapped by an outer pervious covering which may be comprised from gauze, non-woven threads, non-woven fabric, or the like. Because the absorbent core material in prior art napkins is usually of considerably lower density than the top sheet material, fluid deposited on the top sheet will not be rapidly transmitted into the core, but rather will tend to spread laterally on the surface of the top sheet, thereby producing an objectionable appearance and feel, causing discomfort and promoting run-off and soiling of undergarments. In addition, fluid absorbed in the core material will tend to migrate back to the surface of the top sheet due to the unfavorable density gradient existing between the top sheet and the absorbent core material, thereby causing the top sheet to feel moist.

OBJECTS OF THE INVENTION favorable capillary size and liquid contact angle gradients which exist between the top sheet and the absorbent core material, regardless of whether the absorbent core material is in a dry or a moist state.

It is'a further object of the present invention to provide a sanitary napkin which is more comfortable to wear due not only to improvements in softness of the relatively dense absorbent core material, but also to an overall reduction in size, particularly toward the rearward portion of the absorbent pad, and to the tendency of the absorbent pad to assume an upwardly concave or U configuration in both the transverse and the longitudinal directions when worn.

It is a further object of the present invention to provide a forward extension of the absorbent pad which is capable of bending relative to the main body of the absorbent pad so as to better conform to the frontal portions of the female body, and thereby form a dam over which body exudate cannot flow.

It is a further object of the present invention to prevent strike-through of body exudate from the lowermost side of a sanitary napkin of the present invention by providing a waterproof backing sheet essentially coextensive with the lowermost layer of absorbent core material.

SUMMARY OF THE INVENTION According to the present invention, an absorbent bandage is provided, preferably in the form of a sanitary napkin, which utilizes more effectively the available absorbent core material provided in the napkin by providing a favorable density gradient between the top sheet and the absorbent core material. This in turn results in corresponding gradients of capillary size and liquid contact angle which cause exuded body fluids to preferentially pass to and accumulate in the absorbent core of the napkin. A non-woven hydrophobic top sheet material having a density range of from approximately 0.03 to approximately 0.13 gm. per cubic centimeter as measured under a load of 50 gm. per square inch and a hydrophilic compressed absorbent core having a density range of from approximately 0.15 to approximately 0.30 gm. per cubic centimeter as measured under a load of 50 gm. per square inch is contemplated in the present invention. Thus, fluid deposited on the surface of the basically hydrophobic top sheet will transfer at a considerably more rapid rate to the more dense compressed absorbent core than is the case with prior art sanitary napkins. Since the absorbent core in a preferred embodiment is basically hydrophilic, it will absorb the moisture transmitted from the top sheet, while the top sheet remains relatively dry.

In one preferred embodiment of the present invention, a sanitary napkin is provided having reduced size, particularly toward the rearward portion thereof, and which, when worn, assumes an upwardly concave or U-configuration in both the transverse and the longitudinal directions. This avoids deformation of the natural contours of the body portions adjacent thereto. The lateral edges portions of the absorbent pad of a sanitary napkin of the present invention are accommodated in the vaults formed by the jointure of each thigh and the adjacent labium majora, while the central portion of the absorbent pad moves downwardly.

The absorbent pad, in one preferred embodiment, is constructed so that it readily assumes an upwardly concave configuration in the transverse direction. This is achieved by providing a longitudinal depression along the central portion of the top surface of the absorbent pad which tends to bias the pad into an upwardly concave or U" shape. Additionally, a transverse slit is provided intermediate the lateral edges of the bottom sheet material at a point in vertical alignment with the forwardmost edge of the main body of the absorbent pad, i.e., that portion of the pad not including the forwardmost extension thereof, thereby relieving the central portion of the absorbent pad of stress when worn, and concentrating the tensile stress induced by application of the napkin to a sanitary belt along the lateral edge portions of the absorbent pad.

In another embodiment, a structure is provided which prevents the flow of discharged fluids over the leading edge of the napkin while simultaneously providing better conformance of the frontal portions of the napkin to the female body. This is provided by structuring the lowermost layer of absorbent core material and the waterproof backing sheet with forward projections extending beyond the main body of the absorbent pad. The aforementioned projections are overwrapped only by top sheet material. The front extension thus formed is free to bend relative to the main body of the absorbent pad, and allows the napkin to conform more readily to individual body shape, thereby effectively forming a dam against the body.

The unique features described above when combined in a preferred embodiment of the present invention result in a sanitary napkin which is more comfortable to the wearer both in terms of fit and dryness, which gives the wearer a greater feeling of security against smearing, run-off and strike-through, and which can be worn for longer periods of time due to more effective utilization of the absorbent core material.

BRIEF DESCRIPTION OF THE DRAWINGS While the specification concludes with claims particularly pointing out and distinctly claiming the subject matter which is regarded as the present invention, it is believed that the invention will be better understood from the following description taken in connection with the accompanying drawings, in which:

FIG. 1 is an exploded perspective view of a sanitary napkin which is one preferred embodiment of the present invention, wherein the individual components are depicted in their unassembled relation;

FIG. 2 is a perspective view showing partial assembly of the components illustrated in FIG. 1, and further depicting the manner in which the top sheet is folded about the other assembled components;

FIG. 3 is a perspective view of one preferred embodiment of a completely assembled sanitary napkin made in accordance with the present invention prior to use by a consumer;

FIG. 4 is a perspective view of one preferred embodiment of a completely assembled sanitary napkin of the present invention shown in its in-use configuration when attached to the clasps of a sanitary belt or holder;

FIG. 5 is an enlarged transverse sectional view of one preferred embodiment of a sanitary napkin of the present invention when placed in use by a consumer, such sectional view being taken at approximately the same point as section line 66 in FIG. 3; and

FIG. 6 is an enlarged transverse sectional view of one preferred embodiment of a completely assembled sanitary napkin of the present invention taken along section line 66 in FIG. 3, showing the napkin in its configuration prior to use.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1, there is shown an exploded view of the individual components of one embodiment of the absorbent bandage of the present invention. It will become apparent as the description proceeds that a sanitary napkin is a most preferred embodiment, although it will be understood that other similar equivalent articles, e.g., disposable diapers, incontinent pads and the like, are within the broad scope of the invention. The components in FIG. I are shown in the same relative position in which they are ultimately assembled.

The preferred construction of a sanitary napkin includes a top sheet 1 which comes in contact with the users skin. The top sheet 1 is preferably a non-woven material. Very good results have been obtained in using a non-woven, needle-punched polyester material having a density in the range of from about 0.03 to about 0.13 gm. per cubic centimeter as measured under a load of 50 gm. per square inch, preferably between approximately 0.03 and 0.08 gm. per cubic centimeter. One such material which has proven highly satisfactory in this service is a non-woven, 3 denier, 2% oz. per square yard, needle-punched polyester fabric having a caliper of approximately 0.09 in. and a density of approximately 0.03 gm. per cubic centimeter, such as is available from Troy Mills, Troy, New Hampshire. While the above mentioned needle-punched polyester material is preferred, the invention can also be practiced with similarly good results by the use of similar or equivalent materials such as: a non-woven, 6 denier, needle-punched polyester fabric having a caliper of approximately 0.11 in. and a density of about 0.04 gm. per cubic centimeter, such as Troy Mills code No. 3001-007500 also available from Troy Mills, Troy, New Hampshire; a non-woven, 6 denier, needlepunched Type 209 polyester fabric having a caliper of either 0.08 in. or 0.09 in. and a density of about 0.04 gm. per cubic centimeter, such as Stearns & Foster grade 0 or grade K material available from The Stearns & Foster Company, Lockland, Ohio; or a resinbonded polyester fabric having a caliper of approximately 0.014 in. and a density of about 0.13 gm. per cubic centimeter, such as Stearns & Foster grade No. 2552 available from The Stearns & Foster Company, Lockland, Ohio. The top sheet material exhibits hydrophobic properties in that it does not readily absorb moisture which comes in contact with it, but rather transmits it to the hydrophilic core layers 2 and 3 which absorb and distribute the moisture. The top sheet 1 has front and

rear extensions

6 and 13 and

lateral extensions

7, 8, 9, 10, 11 and 12. A detailed description of how these extensions are utilized to join the top sheet to the other components of the sanitary napkin will be given following a more complete description of the individual components.

The absorbent core is preferably comprised of a multiplicity of layers of airfelt or equivalent materials, e.g., cellulose wadding, rayon mat, etc. Preferably three layers of airfelt are utilized, ordinarily two upper layers of basically hydrophilic compressed airfelt 2, and a lowermost layer 3, the latter being of similar configuration to the layers 2 except for the addition of a trapezoidal extension 3a at its leading edge, i.e., its forward portion 3a as shown in FIGS. 1 and 2. By compressing the airfelt in this particular application, the density of the core material can be increased from approximately 0.04 gm. per cubic centimeter as measured under a load of 50 gm. per square inch to something in the range of approximately 0.15 to approximately 0.30 gm. per cubic centimeter as measured under the same load, preferably between approximately 0.22 and 0.26 gm. per cubic centimeter, thus producing a very favorable density gradient with respect to the low density top sheet 1.

Immediately following dry compression, the densified airfelt in a preferred embodiment may be subjected to any one of a number of processes designed to provide acceptable lateral softness in the finished product, e.g., mechanical microcreping carried out between differentially loaded rubber belts and/or a differentially loaded rubber belt and a hard surface. Such a process imparts softness and compliance to the airfelt, which would not otherwise result if only dry compression were utilized. A test designed to measure the flexual rigidity or stiffness of paperboard, which utilizes a Taber V- Stiffness Tester, Model 150 B, as manufactured by the Taber Instrument Corporation of North Tonawanda, New York, can also be used to measure the flexural rigidity or stiffness of the absorbent core material, in this case compressed airfelt, by determining the bending moment in gram-centimeters necessary to defleet the free end ofa 3.81 cm. (1.5 in.) wide vertically clamped specimen of compressed airfelt having an overall length of 6.99 cm. (2.75 in.) from its center line when the load is applied 5 centimeters away from the clamp. Compressed airfelt having a caliper of between 0.127 and 0.152 cm. (0.05 and 0.06 in.) such as is used in the absorbent core of a preferred embodiment of the present invention typically exhibits a softness range between 1.2 and 8.7 gram-centimeters, whereas compressed airfelt of equivalent caliper which has not been subjected to any type of process to impart softness after dry compression typically exhibits a softness range between 10 and 18 gram-centimeters. The use of compressed airfelt in this particular application allows the pad size to be kept to a minimum, i.e, the caliper of a layer of uncompressed airfelt is typically reduced from approximately 0.35 in. as measured under a load of 50 gm. per square inch to approximately 0.09 in. to 0.10 in. under the same load after dry compression and trimming to the preferred size, thereby permitting maximum use of absorbent material. ln addition, pre-compressing the airfelt prior to assembly of a napkin of the present invention provides a mechanism by which the airfelt is able to absorb greater quantities of fluid, since the airfelt will tend to expand back toward its original uncompressed state when it absorbs liquid. While in a preferred structure the absorbent core comprises three layers, e.g., the

layers

2, 2 and 3, it will be understood that it is possible to make the absorbent core from any number of layers, i.e., one or more layers, depending upon the desired construction of the finished product.

The waterproof backing sheet 4 can be of any pliable waterproof material. One such material which has proven satisfactory in this service is embossed hard polyethylene having an embossed caliper of approximately 2.3 mils, such as is available from Visqueen Division of Ethyl Corporation, Terre Haute, Indiana. The waterproof backing sheet 4 is essentially coextensive with the lowermost layer of absorbent core material 3. The primary purpose of the waterproof backing sheet 4 is to prevent strike-through of absorbed body fluids from the absorbent core of the pad to the lowermost surfaces of the napkin. In one alternate embodiment of a sanitary napkin of the present invention, the waterproof backing sheet 4 might be perforated by a series of apertures designed to permit air circulation through the lower portions of the pad to the interior surfaces which are in contiguous association with the wearers skin. In yet another alternate embodiment of a sanitary napkin of the present invention, the waterproof backing sheet 4 might be eliminated altogether. However, in the event waterproof backing sheet 4 is either perforated or entirely eliminated, it would be necessary to extend top

sheet lateral extensions

9, 10, 11 and 12 to overlap each other on the lower side of the napkin so as to preclude strike-through of body exudate from the top sheet 1, through the absorbent core layers 2 and 3, and ultimately through the bottom of the napkin.

The bottom sheet 5 is preferably formed from two superposed rectangular strips of material having approximate dimensions of 3 in. wide by 18 in. long in one preferred embodiment of the present invention. Reemay, a basically hydrophobic, spunbonded, low basis weight, non-woven, polyester fabric having a measured weight of about 0.4 oz. per square yard, such as is available from E. I. Du Pont De Nemours & Co., Inc., Wilmington, Delaware, has been found to produce very satisfactory results in this service. Two sheets of the above described Reemay are used in a preferred embodiment to provide sufficient tensile strength. However, a single sheet of heavier Reemay or other similar material having a higher degree of tensile strength might also be used for this purpose. Other materials having equivalent porosity, weight and strength and could also be employed to produce comparable results. Some specific examples include: Cerex, a spunbonded, nonwoven nylon available from Monsanto Company, St. Louis, Missouri; Typar, a spunbonded, non-woven polypropylene available from E. l. Du Pont De Nemours & Co., Inc., Wilmington, Delaware; Tyvek, a spunbonded, non-woven polyethylene available from E. l. Du PontDe Nemours & Co., Inc., Wilmington, Delaware; and an acrylic, resin-bonded, carded, nonwoven polyester such as Stearns & Foster grade No. 2551 available from The Stearns & Foster Company, Lockland, Ohio. As will be pointed out, this material is not used as an overwrap in the true sense. Its purpose is to provide a carrier means for the absorbent core layers 2 and 3, the waterproof backing sheet 4, and the top sheet 1. The end extensions of the bottom sheet 5 provide tab material as a means of attachment to a sanitary belt such that the napkin is caused to assume an upwardly concave conformation in both the longitudinal and the transverse directions, thus providing better conformance to the female anatomy in the area of the vulva.

Referring now to FIG. 2, the method of assembly of the components depicted in FIG. 1 is more clearly illustrated. The absorbent core member is formed by superposing the lowermost layer of absorbent core material 3 over the waterproof backing sheet 4, and then superposing the remaining layers of absorbent core material 2 on top of the lowermost absorbent core layer 3 in such a manner that the rearward portions (the right end as viewed in FIG. 2) of all the absorbent core layers and the waterproof backing sheet 4 are in vertical alignment.

The bottom sheet is prefolded upwardly by means of heat and pressure which tends to bond the superposed sheets together and to form lateral tabs and 16 at the leading edge of the napkin,

lateral tabs

17 and 18 adjacent the parallel lateral edges of absorbent core layers 2 and 3, and lateral tabs 19 and adjacent the tapered lateral edges at the rearward portion of absorbent core layers 2 and 3.

In order to provide a means of attachment at the rear of a sanitary napkin of the present invention, two slits 21 are made extending from the lateral edge portions of

tabs

19 and 20 of the bottom sheet 5, substantially perpendicular to the longitudinal axis of the napkin.

Each slit 21 penetrates the bottom panel 22 of the bottom sheet material 5 to a distance within approximately A in. to /z in. of the longitudinal axis of the napkin. From the position of those portions of

tabs

19 and 20 which form the extension rearward of slits 21, as illustrated in FIG. 2, one additional fold is made from each side of the said rearward extension. Each additional fold line (designated 29 in FIG. 2) runs from the inwardmost edge of each lateral slit 21 to a point approximately one-third of the way in from the corresponding lateral edge as measured at the rearwardmost edge of the rearward extension illustrated in FIG. 2. The result of these two additional folds is a tab 24 which tapers in width from front to back from approximately 1 in. to /2 in. at a point corresponding with slits 21 to approximately /2 in. to A in. at its rearwardmost portion, as shown in FIG. 3. Heat and pressure are applied to bond the series of overlapping folds forming the rearward attachment tab 24 together.

The transverse slits 21 in one preferred embodiment of the present invention are in vertical alignment with a point approximately /2 in. to 1 /2 in. from the rearwardmost edge of the tapered segment of the absorbent core material. Although the exact location of slits 21 is not critical, it is preferably forward from the rearwardmost edge of the absorbent core material, since overwrapping the juncture between the folded rearward tab 24 and the unfolded portions of bottom panel 22 of the bottom sheet 5 with overlapping tabs 11 and 12 of top sheet 1 impartsadditional strength to the rearward attachment tab 24.

With

tabs

15, 16, 17, 18, and those portions of

tabs

19 and 20 forward of slits 21 prefolded to assume an upwardly concave or U-configuration in the transverse direction, the assemblage comprised of the waterproof backing sheet 4, the lowermost layer of absorbent core material 3, and preferably two layers of absorbent core material 2, is placed within the trough-like structure formed by the bottom sheet 5 such that the leading edges of absorbent core layers 2 are in vertical alignment with a transverse slit 14 which is made intermediate the lateral edge portions of bottom panel 22 of the bottom sheet 5 prior to insertion of the absorbent material.

Tabs

17 and 18 of the bottom sheet 5 are folded over the absorbent core assemblage so as to overlap by approximately 4 in. to k in. the parallel lateral edges of the uppermost layer of absorbent core material 2. In similar fashion, those portions of

tabs

19 and 20 forward of slits 21 overlap the uppermost layer of absorbent core material 2 along its rearward lateral edges which are not parallel to each other in such a manner that

tabs

19 and 20 overlap each other toward the rearward portion of the absorbent core. This is illustrated in FIG. 2.

Tabs

15 and 16 at the leading edge ofthe bottom sheet 5 are folded inwardly, and heat and pressure are applied so as to bond the overlapping tabs together to form a forward extension 27, as shown in FIGS. 3 and 4, which serves as a means of attachment to the front of a sanitary belt or holder.

The fold lines shown on the top sheet 1 in FIGS. 1 and 2 define a shape identical to that of the lowermost absorbent core layer 3 and the waterproof backing sheet 4. The top sheet 1 is joined to the balance of the structure in such a manner that the shape defined by the fold lines is in vertical alignment with the lowermost absorbent core layer 3 and the waterproof backing sheet 4.

Tabs

9 and 10 of the top sheet 1 are adjacent the parallel lateral edges of absorbent core layers 2 and 3, while tabs 11 and 12 are adjacent the nonparallel rearward lateral edges of absorbent core layers 2 and 3. Those portions of

tabs

9, 10, 11 and 12 which overlap by approximately /z in.-% in. the bottom panel 22 of the bottom sheet material 5 are attached to the bottom surface thereof by means of beads of glue 28, as shown in FIGS. 5 and 6. The rearwardmost tab 13 of the top sheet 1 overlaps by approximately /2 in.-% in. the rearwardmost end of absorbent core layers 2 and 3 and the lowermost surface of the waterproof backing sheet 4, and is secured thereto by means of glue. Thus, the main body of the absorbent core, i.e., absorbent core layers 2 and 3, excluding the forward extension 30 of the lowermost absorbent core layer 3, is secured to the bottom sheet material 5.

Triangular tabs 7 and 8 and rectangular tab 6 of top sheet 1 are folded so as to totally enclose the forwardmost extension 3a of the lowermost layer of absorbent core material 3 and the forwardmost extension of the waterproof backing sheet 4. Rectangular tab 6 is folded and glued to the waterproof backing sheet 4, followed by triangular tabs 7 and 8 which are folded and glued to both the rectangular tab 6 and those portions of waterproof backing sheet 4 which are exposed.

One glue which has proven satisfactory for use in assembling a sanitary napkin of the present invention is ELVACE 1873, which is a water-resistant glue available from E. I. Du Pont De Nemours & Co., Inc., Wilmington, Delaware. Other water resistant glues having similar properties could also be utilized.

Addition of the top sheet 1 as described above results in a structure which places the top sheet in contiguous association not only with the uppermost surface of the uppermost absorbent core layer 2, but also with the up permost surface of the forward extension 3a of the lowermost absorbent core layer 3. Thus, absorbent core layers 2 and 3 are totally enclosed either by top sheet 1 or waterproof backing sheet 4.

In order to impart a bias to a napkin of the present invention to assume an upwardly concave configuration in the transverse direction when worn, a longitudinally extending depression 25 of relatively narrow width is pressed into the central portion of the main body of the absorbent pad 26 at the uppermost surface of the top sheet 1 (see FIG. 3). This is done by placing a steel rod approximately 3 /2 inches long and 4 inch in diameter along the horizontal axis of the napkin, and applying a force of approximately 4,000 lb. uniformly along the length of the rod. The central depression 25 in a preferred embodiment of the present invention is essentially co-extensive with the lateral parallel edges of absorbent core layers 2 and 3, as illustrated in FIG.

3. However, said central depression 25 could be considerably shorter than is illustrated in FIG. 3 or could extend nearly all the way across the entire upper surface of the top sheet 1 in a longitudinal direction.

In the alternative, an interrupted central depression or a series of depressions parallel to the longitudinal axis of the napkin could be used to accomplish the same result. Other means may also be provided to impart the desired bias to the napkin such that it will tend to assume an upwardly concave configuration. For example, in place of the preferred depression 25, the upper core layer 2 may be formed such that its longitudinal central area is of lesser thickness. In still another form, the same advantages may be imparted to the napkin by providing a longitudinal central slit in the core layer 3, or in both the core layer 3 and the lowermost core layer 2. These and other means for providing this function will be apparent to those skilled in the art.

FIG. 3 represents a preferred embodiment of a completely assembled sanitary napkin of the present invention prior to use. The bias to assume an upwardly concave configuration in the transverse direction prior to use due to the longitudinal central depression is clearly illustrated in FIG. 6, which is a transverse sectional view taken along section line 6-6 of FIG. 3. The central depression 25 also has the effect of densifying the absorbent core material in the immediate vicinity of the depression, thereby making the density gradient most favorable in the area where body fluids are most likely to be initially deposited.

FIG. 6 illustrates the manner in which the various components of a preferred embodiment of the instant invention are held in contiguous association. The absorbent core layers 2 and 3 and the waterproof backing sheet 4 are merely stacked one upon the other. The bottom sheet material 5 is provided with

tabs

17 and 18 at its lateral edges at this particular transverse section, the outermost portions of which overlap the uppermost surface of the uppermost layer of absorbent core material 2. With the exception of a few drops of glue which may be applied to hold the bottom sheet material 5 in place while the top sheet 1 is being added, the overlapping portions of

tabs

17 and 18 and the overlapping portions of

tabs

19 and 20 forward of transverse slits 21 are held in place merely by a sandwiching effect between the top sheet 1 and the uppermost layer of absorbent core material 2.

A sanitary napkin of the present invention exhibitsimprovements not only in terms of comfort to the wearer, but also in terms of the efficiency with which the napkin is able to retain and absorb body exudate, while at the same time preventing strike-through, and minimizing the possibility of run-off, slippage and smearing. A sanitary napkin of the present invention has a width at its widest point ranging from approximately 2 to 3 inches, most desirably approximately 2- 4 inches. The rearward portion of such a napkin is generally tapered from the maximum width to a dimension ranging from approximately /2 to 1- /2 inches, most desirable approximately 1 inch. The forward extension 23 of the absorbent pad of a napkin of the present invention tapers from the maximum width to a dimension ranging between V2 and l-& inches, most desirably approximately 1 inch. The overall length of the napkin along its longitudinal axis, exclusive of its attachment tabs, typically ranges between approximately 6-/2 and 8- /6 inches, most desirably approximately 7-% inches.

The longitudinal distance over which the rearward taper of the absorbent pad 26 occurs ranges between approximately 3 and 4 inches, most desirably approximately 3-/2 inches. The longitudinal distance over which the forward taper of the forward extension 23 of the absorbent pad occurs is in the range of approximately /2 to l-% inches, most desirably approximately 1 inch. The forward attachment tab 27 typically ranges between approximately 3- /2 and 5- /2 inches in length, most desirably about 4- /2 inches as measured from the leading edge of the main body of the absorbent pad 26, i.e., that portion of the absorbent pad not including the forwardmost extension 23 thereof. The rearward attachment tab 24 typically ranges between approximately 5- /2 and 7- /2 inches in length, most desirably about 6- /2 inches as measured from the rearwardmost edge of the main body of the absorbent pad 26.

It is recognized that although only one preferred embodiment of the present invention has been described above, a sanitary napkin having an elliptical or any other equivalent configuration of the same general proportions as those listed above could be utilized to effect a similar result.

It will be noted from FIG. 4 that a napkin of the present invention is intended to be worn with its wider portion toward the front of the body, with the forwardmost extension 23, which is free to bend relative to the main body of the absorbent pad, to a considerably higher elevation than the main body of the absorbent pad 26.

A sanitary napkin of the present invention has been found to have better conformation to the female anatomy. Its tapered rearward portion is sufficiently narrow to avoid bunching in the anal area, while its maximum width is such that the lateral edge portions of the absorbent pad contact the null point of the groin line, i.e., where there is virtually no movement of the thighs relative to the trunk of the body. Each lateral edge portion of the absorbent pad is accommodated in a vault formed by the juncture of each thigh and the adjacent labium majora, such that relative motion between the inner portions of the thigh and each lateral edge portion of the absorbent pad is essentially non-existent. This is best illustrated in FIG. 5, which is an enlarged transverse sectional view of such a napkin when placed in use. Thus, the size and shape of a sanitary napkin of the present invention acting in conjunction with the other structural features of the present invention eliminate the downwardly concave or inverted U transverse configuration which is normally assumed by prior art rectangular style sanitary napkins, thereby minimizing the possibility of run-off of body exudate.

It should be noted that the overall reduction in size of the absorbent pad of a sanitary napkin of the present invention, particularly toward its rearward portion, would not be practical without the unique ability of the top sheet 1 and absorbent core layers 2 and 3 of the present invention to rapidly transmit and absorb body exudate much more effectively than is possible with conventional overwrap and core materials due to the favorable density gradient existing between the top sheet 1 and the absorbent core layers 2 and 3. The favorable density gradient in turn provides a diminishing capillary size gradient and a favorable liquid contact angle gradient, both of which exist regardless of whether the absorbent core material is in a moist or a dry state.

In the present invention, stress on the central portion of the main body of the absorbent pad 26 is relieved by means of a transverse slit 14 or other similar interruption in the bottom sheet material 5. The transverse discontinuity or slit 14 in the bottom sheet material is located in bottom panel 22 intermediate the lateral edges of the forward attaching tab 27, which is shown in FIGS. 3 and 4. The transverse interruption or slit 14 is preferably in vertical alignment with the leading edge of absorbent core layers 2, Le, with the leading edge of the main body of the absorbent pad 26. The slit 14 may also be as much as 1 inch from the aforesaid vertical alignment to achieve the objects of the invention. The transverse interruption or slit 14 functions to transmit stress imposed by tension on the

attachment tabs

27 and 24, during wearing, to the lateral edges of the absorbent pad 26. Selective placement of the tensional stress at the lateral edges of the absorbent pad tends to form the absorbent pad 26 into a cupped receptacle for the collection of body exudate, since, as shown in FIG. 5, the lateral edges of the core are held snugly against the body in the vaults formed by the juncture of each thigh and the adjacent labium majora, while the central portion of the absorbent pad 26 along the longitudinal axis is free to move downwardly, thereby bridging the labia majora. The longitudinal depression 25 illustrated in FIGS. 3, 5 and 6 imparts a bias to the absorbent pad 26 which, when coupled with the forces induced by the

tabs

27 and 24, tends to cause the longitudinal axis of the absorbent pad to move downwardly. Thus, the cupping of the absorbent pad 26 is caused principally by the addition of the slit 14 (which causes selective application of stress from tabs 27 and 24) and is abetted by the depression 25.

The present invention also discloses a sanitary napkin construction in which a forward extension 23 of the absorbent pad 26 is formed from the forwardmost extension 3a of the lowermost layer of absorbent core material 3, the forwardmost extension of the waterproof backing sheet 4, and the forwardmost extension of the top sheet 1 which totally encloses the forwardmost extension 3a of the lowermost absorbent core layer 3 and the forwardmost extension of the waterproof backing sheet 4 by means of overlapping rectangular tab 6 and overlapping triangular tabs 7 and 8. The forward extension of the absorbent pad thus formed is free to bend relative to the main body ofthe absorbent pad 26 along a line corresponding with the leading edge of absorbent core layers 2. This is due to the fact that the forward extension 23 is not in any way confined by

tabs

17 and 18 of the bottom sheet material 5, as is the main body of the absorbent pad 26. In addition, since the forward extension 23 is comprised of only one layer of absorbent core material 3, the waterproof backing sheet 4, and the top sheet 1, very little effort is required to bend the forward extension 23 relative to the main body of the absorbent pad 26. The ability of the forward extension 23 to bend with ease relative to the main body of the absorbent pad 26 provides both improved fit and comfort, since it causes the absorbent pad to assume an upwardly concave or U-shape in the'longitudinal direction with the application of relatively small tensional forces.

The forward extension 23 also provides a capacity advantage when worn, since it forms a dam to restrain the flow of body exudate over the front of the napkin. In addition, because of the compliant nature of the top sheet 1 and the fact that the forward extension 23 has less bulk than the main body of the absorbent pad 26, it is more pliable and tends to conform to the female body with relative ease, thereby minimizing the formation of any ridges or troughs along its lateral edges. Elimination of ridges and troughs along the lateral edges of a sanitary napkin is desirable because their presence tends to promote the flow of body exudate toward the lateral edges of the napkin, and hence increases the possibility of run-off and consequent soiling of undergarments.

The front dam formed by the forward extension 23, cooperates when worn with the transverse interruption or slit 14 in the bottom sheet material 5 and the longitudinal depression 25 such that while the lateral edges of the main body of the absorbent pad 26 are held snugly against the body due to the tensional forces induced in the lateral edge portions of the absorbent pad as a result of the slit, the forward extension 23 conforms easily and hence forms a snug fit against the frontal portions of the body, while the central depression 25 causes the central portion of the main body of the absorbent pad 26 to move downwardly to bridge the labia majora and form a receptacle for the collection of menses or other body exudate. Menses or other body exudate cannot readily escape toward the rearward portion of the absorbent pad 26 due to the fact that its rearwardmost edge is so narrow that the tensional forces along the lateral edges of the main body of the absorbent pad intersect at its rearwardmost portion, thereby forming a sealagainst the body rearward of the vulva.

Thus a triangular shaped dam is formed about the periphery of the vulva, while the central portion of the napkin is encouraged to move downwardly, thus allowing it to form a totally enclosed receptacle for the collection of menses or other body exudate. Fluid deposited on the top sheet 1 is retained within the totally enclosed receptacle so formed until it can be transmitted from the topsheet 1 into the absorbent core layers 2 and 3. Run-off of menses or other body exudate due to exceptionally heavy flow is thereby minimized in any given direction.

Therefore, although a sanitary napkin of the present invention is more comfortable to the wearer due to its reduced size, its revised shape and its upwardly concave conformation in both the longitudinal and the transverse directions to better fit the female anatomy, it is also considerably more effective in retaining and absorbing menses or other body exudate than a sanitary napkin of conventional rectangular design having considerably more surface area and absorbent core material present. It is also more effective and more comfortable than sanitary napkins of the prior art having tapered segments at their rearward portion, due to the unique interaction of the transverse slit 14 in the bottom sheet material 5, the central longitudinal depression 25 in the main body of the absorbent pad 26, and the forward extension of the absorbent pad 23 which cause the napkin to assume an upwardly concave conformation in the area of the labia majora, thereby minimizing contact between the top sheet 1 and the wearers skin, and at the same time minimizing the formation of ridges and troughs which are usually formed along the lateral edges of a flat sanitary napkin when it is attached to a sanitary belt or holder.

As has been mentioned earlier in this specification, the overall reduction in size of the absorbent pad of a sanitary napkin of the present invention to better fit the female anatomy would not be practical unless the core material were more effectively utilized to absorb menses or other body exudate than is the case with prior art sanitary napkins. In sanitary napkin construction it is generally desirable for the absorbent structure to immediately accept body exudate, rapidly transport the exudate away from the discharge source and effectively contain the exudate within the confines of the napkin, while the top surface of the napkin is maintained relatively dry. In addition, the absorbed exudate should not be allowed to spread to the sides of the napkin, run over the top edges of the napkin, or soak through the bottom of the napkin, and this is especially true where the absorptive capacity of the napkin has not been fully utilized.

As illustrated in FIGS. 1, 2, and 6, a preferred embodiment of the present invention consists of three layers of absorbent core material, compressed airfelt in this instance, the lowermost layer of which has a trapezoidal forward extension. The airfelt is densified by dry compression and may be subjected to any one of a number of processes designed to provide acceptable lateral softness in the finished product, e.g., mechanical micro-creping carried out between differentially loaded rubber belts and/or a differentially loaded rubber belt and a hard surface. Dry compression increases the airfelts density by reducing its physical thickness, while any one of the softening processes can be used to impart softness and compliance which would not otherwise result if only dry compression were utilized. The stiffness or flexural rigidity of a specimen of compressed airfelt such as is utilized in a preferred embodiment of the present invention having an overall width of 3.81 cm. 1.50 in.) and an overall length of 6.99 cm. (2.75 in.) can be measured by means of a Taber V-5 Stiffness Tester, Model 150 B, as manufactured by the Taber Instrument Corporation of North Tonawanda, New York. A procedure identical to that utilized to measure the stiffness or flexural rigidity of paperboard may be utilized. The procedure involves determining the required bending moment in gram-centimeters to deflect the free end of a 3.81 cm. (1.50 in.) wide vertically clamped specimen as described above l5from its center line when the load is applied 5 cm. away from the clamp. Compressed airfelt such as is used in a preferred embodiment of the present invention having a caliper of between 0.127 and 0.152 cm. (0.05 and 0.06 in.) which has been subjected to any of the softening processes well known in the art typically exhibits a softness range between about 1.2 and 8.7 gramcentimeters, whereas compressed airfelt of equivalent caliper which has not been subjected to any type of softening process typically exhibits a softness range between and 18 gram-centimeters. It is to be understood that various thicknesses of compressed airfelt could be utilized in the present invention. However, the Taber softness range would differ for different thicknesses of material and, therefore, the preferred Taber softness range would have to be individually determined for any given thickness of material.

In a sanitary napkin of the present invention having a total weight of approximately 10 to 12 gm., the total weight ofthe absorbent core material is typically in the range of approximately 7 to 8 gm. A preferred embodiment of the present invention has the machine direction of the compressed airfelt aligned transverse to the longitudinal axis of the napkin. However, there does not appear to be a discernible difference in the characteristics of the finished product when the machine direction of the airfelt is aligned parallel to the longitudinal axis of the napkin.

If desired, a resin spray (e.g., Rohm and Haas HA-8) or other bonding agent may be applied to the exterior surfaces of

absorbent layers

2 and 3 while they are still at low density, i.e., prior to compression, to reduce the tendency of the airfelt to shred and tear when dry and ball up and rope when wet and to improve the surface dryness. However, since a sanitary napkin of the present invention experiences virtually no relative movement with respect to itself or with respect to the trunk of the body or the inner portions of the thighs, this is not essential to the practice of the invention.

Such a strength imparting treatment would be of greatest benefit in absorbent bandages which experience considerable internal movement and shifting, such as disposable diapers, etc. Bonding of the exterior surfaces of the absorbent core members to impart both tensile and cohesive strength could be carried out to impart wet strength to the airfelt by bonding the surface fibers together at contact points.

In a preferred embodiment of the present invention, the top sheet 1 is in contiguous association with the uppermost surface of the uppermost layer of absorbent core material 2 and the uppermost surface of the forward extension 3a of absorbent core layer 3. All the absorbent core layers are in contiguous association with each other, while the lowermost surface of the lowermost absorbent core layer 3 is in contiguous association with the waterproof backing sheet 4. Due to the hydrophobic nature and the low density of the top sheet 1 in a preferred embodiment of the present invention, fluid deposited on the top sheet migrates rapidly towards the more dense absorbent core layers 2 and 3 which are basically hydrophilic, rather than spreading laterally across the surface of the top sheet 1. The rapid transmission of fluid caused by capillary attraction keeps the top sheet feeling dry, and, therefore, more comfortable to the wearer. When the uppermost absorbent core layer 2 makes contact with the fluid, it begins to absorb the fluid and its lattice structure begins to expand, particularly in the area of the longitudinal depression 25. As the pore size in the wetted portion of the absorbent core increases, it creates a favorable density gradient between the moist and dry segments of absorbent core layers 2 and 3. Thus fluid is rapidly transmitted not only from one layer to the next, but also toward the lateral edges of each layer of absorbent core material. Because the density of the top sheet 1 remains basically unchanged due to its hydrophobic nature, its pore size remains larger than the pore size of even the moist layers of

absorbent core material

2 and 3. Therefore, fluid which has been absorbed by absorbent core layers 2 and 3 does not tend to migrate back towards the top sheet 1. Since the absorbent core layers 2 and 3 are covered on their uppermost and lateral edge portions by the basically hydrophobic top sheet 1, and since the extensions of the hydrophobic top sheet 1 are bonded to the lowermost side of either the bottom sheet material 5 or the waterproof backing sheet 4, absorbed fluid is trapped within a capsule-like member formed by the top sheet I and the waterproof backing sheet 4. Thus, the top sheet 1 acts as a unidirectional flow member which permits the flow of fluid only towards the absorbent core layers 2 and 3 and not in the reverse direction. In addition, since a sanitary napkin of the present invention is not subjected to compressional forces by the inner portions of the thighs of the wearer, there is virtually no tendency to force absorbed fluids from the absorbent core layers 2 and 3 to the top sheet 1 due to the application of pressure. This tends to promote longer wearing times, since the top surface of the pad feels drier and has a less objectionable appearance. Longer wearing times in turn permit more effective utilization of the absorptive capacity of absorbent core layers 2 and 3. The waterproof backing sheet 4, meanwhile, gives the user confidence to wear the pad for longer periods of time since she is protected against strike-through.

Many modifications of the above invention may be used and it is not intended to hereby limit to the particular embodiments shown or described. The terms used in describing the invention are used in their descriptive sense and not as terms of limitation, it being intended that all equivalents thereof be included within the scope of the appended claims.

What is claimed is:

1. An absorbent bandage, comprising:

a. a hydrophilic absorbent core of compressed absorbent material having a density throughout of from about 0.15 to about 0.30 gm. per cubic centimeter as measured under a load of 50 gm. per square inch, 21 0.05 0.06 in. thick by 1.50 in. wide specimen of said absorbent core material having a Taber softness between about 1.2 and about 8.7 gramcentimeters;

b. a hydrophobic topsheet having a density substantially less than that of said absorbent core secured in superposed relation to said absorbent core, said absorbent core and said topsheet comprising an absorbent pad for rapidly absorbing and retaining body exudate; and a bottom sheet underlying and secured to said absorbent pad for supporting said absorbent pad inuse.

2. The absorbent bandage of claim 1, including a thin, flexible backsheet of waterproof material underlying and co-extensive with said absorbent core and located intermediate with said absorbent core and said bottom sheet, said waterproof backsheet thereby preventing strike-through of body exudate absorbed by said absorbent core to the lowermost surface of said bandage.

3. The absorbent bandage of claim 1, wherein the lowermost surface of said hydrophilic absorbent core is completely overwrapped by the overlapping portions of said hydrophobic topsheet, thereby preventing strikethrough of body exudate absorbed by said sbsorbent core to the lowermost surface of said bandage.

4. The absorbent bandage of claim 1, wherein said hydrophilic absorbent core is comprised of compressed airfelt.

5. The absorbent bandage of claim 4, wherein the exterior surfaces of the airfelt have been treated with a wet-strengthening agent prior to initial compression to bond the surface fibers of the airfelt together at contact points.

6. The absorbent bandage of claim 1, wherein said hydrophobic topsheet is comprised of non-woven, needle-punched polyester fabric having a density of from about 0.03 to about 0.13 gm. per cubic centimeter as measured under a load of 50 gm. per square inch.

7. The absorbent bandage of claim 1, wherein said bottom sheet is comprised of hydrophobic, spunbonded, low basis weight, non-woven polyester fabric.

8. An absorbent bandage suitable for use as a catamenial or an incontinent device, comprising:

a. an absorbent pad having reduced overall width toward its rearwardmost portion;

b. a bottom sheet underlying and secured to said absorbent pad, said bottom sheet having forward and rearward extensions projecting substantially beyond said absorbent pad for supporting said absorbent pad in-use;

c. longitudinally extending means in said absorbent pad for imparting an upwardly concave bias to said absorbent pad in the transverse direction; and

d. a discontinuity in the forward extension of said bottom sheet proximate to the forward edge of said absorbent pad and transversely oriented to the longitudinal axis of said absorbent bandage to concentrate normal in-use tensile forces applied to said forward and rearward bottom sheet extensions along the lateral edge portions of said absorbent pad, said concentration of tensile forces in cooperation with the reduced overall width of the rearwardmost portion of said absorbent pad and the aforesaid longitudinally extending means for imparting bias causing said absorbent pad to assume an upwardly concave conformation in both the longitudinal and the transverse directions to prevent run-off and smearing of body exudate deposited on the uppermost surface of said bandage.

9. The absorbent bandage of claim 8, wherein said longitudinally extending means for imparting an upwardly concave bias to said absorbent pad is comprised of a longitudinally extending depression of relatively narrow width, said depression being centrally-located in the uppermost surface of said absorbent pad.

10. The absorbent bandage of claim 8, wherein said discontinuity in the forward extension of said bottom sheet is comprised of a slit located intermediate the lateral edge portions of said forward extension, said slit being transversely oriented to the longitudinal axis of said absorbent bandage.

11. An absorbent bandage suitable for use as a catamenial or an incontinent device, comprising:

a an absorbent pad having reduced overall width toward its rearwardmost portion, said absorbent pad being comprised of a hydrophilic absorbent core of compressed absorbent material having a density of from about 0.15 to about 0.30 grams per cubic centimeter as measured under a load of 50 gm. per square inch, a 0.05 0.06 in. thick by 1.50 in. wide specimen of said absorbent core material having a Taber softness between about 1.2 and about 8.7 gram-centimeters, and a hydrophobic topsheet secured in superposed relation to said absorbent core, said topsheet having a density of from about 0.03 to about 0.13 gm. per cubic centimeter as measured under a load of 50 gm. per square inch;

d. a discontinuity in the forward extension of said bottom sheet proximate to the forward edge of said absorbent pad, whereby normal in-use tension on said forward and rearward bottom sheet extensions in cooperation with the reduced overall width of the rearwardmost portion of said absorbent pad and the aforesaid longitudinally extending means for imparting bias causes said absorbent pad to assume an upwardly concave conformation in both the longitudinal and the transverse directions to prevent run-off and smearing of body exudate deposited on the uppermost surface of said bandage.

12. The absorbent bandage of claim 11, wherein said longitudinally extending means for imparting an upwardly concave bias to said absorbent pad is comprised of a centrally-located, longitudinally extending slit in the lowermost surface of said absorbent core.

13. An absorbent bandage suitable for use as a catamenial or an incontinent device, comprising an absorbent pad having a main body portion and a forward extension, said forward extension being of lesser bulk than said main body portion, and a bottom sheet having forward and rearward extensions projecting substantially beyond said absorbent pad underlying and secured to said main body portion but not to said forward extension, the forward extension of said absorbent pad being free to bend relative to said bottom sheet and to the main body portion of said absorbent pad, whereby normal in-use tension on said forward and rearward bottom sheet extensions causes the forward extension of said absorbent pad to bend upwardly relative to the main body portion to provide a dam for restraining excessive forward flow of body exudate.

14. An absorbent bandage suitable for use as a catamenial or an incontinent device, comprising an absorbent pad having a main body portion and a forward extension, the main body portion of said absorbent pad having reduced overall width toward its rearwardmost end, and a bottom sheet having forward and rearward extensions projecting substantially beyond said absorbent pad underlying and secured to said main body portion, the forward extension of said absorbent pad being free to bend relative to said bottom sheet and to the main body portion of said absorbent pad, whereby normal in-use tension on said forward and rearward bottom sheet extensions causes the forward extension of said absorbent pad to bend upwardly relative to the main body portion to provide a dam for restraining excessive forward flow of body exudate, said absorbent bandage including longitudinally extending means in said absorbent pad for imparting an upwardly concave bias to said absorbent pad in the transverse direction, and a transversely oriented discontinuity in the forward extension of said bottom sheet proximate to the forward edge of the main body portion of said absorbent pad, whereby normal in-use tension on said forward and rearward bottom sheet extensions in cooperation with the reduced overall width toward the rearwardmost end of said absorbent pad and the aforesaid longitudinally extending means for imparting bias causes said absorbent pad to assume an upwardly concave conformation in both the longitudinal and the transverse directions, thereby forming, in cooperation with the forward extension of said absorbent pad, a closesided, cupped receptacle about the vulva for the collection and retention of body exudate.

15. The absorbent bandage of claim 14, wherein said absorbent pad has a maximum width of between about 2 inches and about 3 inches, said width tapering to between about /2 inch and about 1 inch at the rearwardmost end of the main body portion of said absorbent pad and to between about /2 inch and about 1- /2 inches at the forwardmost end of the forward extension of said absorbent pad, said absorbent pad having an overall length, including said forward extension, of between about 6- /2 inches and about 8- /2 inches.

16. The absorbent bandage of claim 14, wherein said absorbent pad is comprised of a hydrophilic absorbent core layer of compressed absorbent material having a density throughout of from about 0.22 to about 0.26 gm. per cubic centimeter as measured under a load of 50 gm. per square inch, a 0.05 0.06 in. thick by 1.50 in. wide specimen of said absorbent core material having a Taber softness between about 1.2 and about 8.7 gram-centimeters, and a hydrophobic topsheet secured in superposed relation to said absorbent core layer, said topsheet having a density of from about 0.03 to about 0.08 gm. per cubic centimeter as measured under a load of 50 gm. per square inch, said absorbent core layer and said topsheet comprising both the main body portion and the forward extension of said absorbent pad.

17. The absorbent bandage of claim 16, including a thin, flexible backsheet of waterproof material underlying and coextensive with said absorbent core layer, said backsheet being located intermediate said absorbent core layer and said bottom sheet in the area ofthe main body portion of said absorbent pad and intermediate said absorbent core layer and the overlapping portions of said topsheet in the area of the forward extension of said absorbent pad, said waterproof backsheet thereby preventing strike-through of body exudate absorbed by said absorbent core layer to the lowermost surface of said bandage.

18. The absorbent bandage of claim 16, wherein said hydrophilic absorbent core layer is comprised of compressed airfelt, said hydrophobic topsheet is comprised of non-woven, needle-punched polyester fabric, and said bottom sheet is comprised of hydrophobic, spunbonded, low basis weight, non-woven, polyester fabric. =l

UNITED STATES PATENT AND TRADEMARK OFFICE CERTIFICATE OF CORRECTION PATENT N0. 3,871,378

DATED 1 March 18, 1975 |NV ENTOR(S) Robert C. Duncan, Grace L. Smith It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below: U

ABSTRACT, line 12, "two" should read top Column 8, line 33, after "weight and strength" delete "and".

. Claim 2 Column 17 line 46 after "intermediate" delete "with" Signed and Scaled this Seventh Day of December 1976 [SEAL] Anesr:

RUTH C. MASON C. MARSHALL DANN A [resting Officer, Commissioner oj'larenrs and Trademarks

Claims

1. An absorbent bandage, comprising: a. a hydrophilic absorbent core of compressed absorbent material having a density throughout of from about 0.15 to about 0.30 gm. per cubic centimeter as measured under a load of 50 gm. per square inch, a 0.05 - 0.06 in. thick by 1.50 in. wide specimen of said absorbent core material having a Taber softness between about 1.2 and about 8.7 gram-centimeters; b. a hydrophobic topsheet having a density substantially less than that of said absorbent core secured in superposed relation to said absorbent core, said absorbent core and said topsheet comprising an absorbent pad for rapidly absorbing and retaining body exudate; and c. a bottom sheet underlying and secured to said absorbent pad for supporting said absorbent pad in-use.

3. The absorbent bandage of claim 1, wherein the lowermost surface of said hydrophilic absorbent core is completely overwrapped by the overlapping portions of said hydrophobic topsheet, thereby preventing strike-through of body exudate absorbed by said sbsorbent core to the lowermost surface of said bandage.

8. An absorbent bandage suitable for use as a catamenial or an incontinent device, comprising: a. an absorbent pad having reduced overall width toward its rearwardmost portion; b. a bottom sheet underlying and secured to said absorbent pad, said bottom sheet having forward and rearward extensions projecting substantially beyond said absorbent pad for supporting said absorbent pad in-use; c. longitudinally extending means in said absorbent pad for imparting an upwardly concave bias to said absorbent pad in the transverse direction; and d. a discontinuity in the forward extension of said bottom sheet proximate to the forward edge of said absorbent pad and transversely oriented to the longitudinal axis of said absorbent bandage to concentrate normal in-use tensile forces applied to said forward and rearward bottom sheet extensions along the lateral edge portions of said absorbent pad, said concentration of tensile forces in cooperation with the reduced overall width of the rearwardmost portion of said absorbent pad and the aforesaid longitudinally extending means for imparting bias causing said absorbent pad to assume an upwardly concave conformation in both the longitudinal and the transverse directions to prevent run-off and smearing of body exudate deposited on the uppermost surface of said bandage.

11. An absorbent bandage suitable for use as a catamenial or an incontinent device, comprising: a an absorbent pad having reduced overall width toward its rearwardmost portion, said absorbent pad being comprised of a hydrophilic absorbent core of compressed absorbent material having a density of from about 0.15 to about 0.30 grams per cubic centimeter as measured under a load of 50 gm. per square inch, a 0.05 - 0.06 in. thick by 1.50 in. wide specimen of said absorbent core material having a Taber softness between about 1.2 and about 8.7 gram-centimeters, and a hydrophobic topsheet secured in superposed relation to said absorbent core, said topsheet having a density of from about 0.03 to about 0.13 gm. per cubic centimeter as measured under a load of 50 gm. per square inch; b. a bottom sheet underlying and secured to said absorbent pad, said bottom sheet having forward and rearward extensions projecting substantially beyond said absorbent pad for supporting said absorbent pad in-use; c. longitudinally extending means in said absorbent pad for imparting an upwardly concave bias to said absorbent pad in the transverse direction; and d. a discontinuity in the forward extension of said bottom sheet proximate to the forward edge of said absorbent pad, whereby normal in-use tension on said forward and rearward bottom sheet extensions in cooperation with the reduced overall width of the rearwardmost portion of said absorbent pad and the aforesaid longitudinally extending means for imparting bias causes said absorbent pad to assume an upwardly concave conformation in both the longitudinal and the transverse directions to prevent run-off and smearing of body exudate deposited on the uppermost surface of said bandage.

13. An absorbent bandage suitable for use as a catamenial or an incontinent device, comprising an absorbent pad having a main body portion and a forward extension, said forward extension being of lesser bulk than said main body portion, and a bottom sheet having forward and rearward extensions projecting substantially beyond said absorbent pad underlying and secured to said main body portion but not to said forward extension, the forward extension of said absorbent pad being free to bend relative to said bottom sheet and to the main body portion of said absorbent pad, whereby normal in-use tension on said forwardand forward and bottom sheet extensions causes the forward extension of said absorbent pad to bend upwardly relative to the main body portion to provide a dam for restraining excessive forward flow of body exudate.

14. And absorbent bandage suitable for use as a catamenial or an incontinent device, comprising an absorbent pad having a main body portion and a forward extension, the main body portion of said absorbent pad having reduced overall width toward its rearwardmost end, and a bottom sheet having forward and rearward extensions projecting substantially beyond said absorbent pad underlying and secured to said main body portion, the forward extension of said absorbent pad being free to bend relative to said bottom sheet and to the main body portion of said absorbent pad, whereby normal in-use tension on said forward and Rearward bottom sheet extensions causes the forward extension of said absorbent pad to bend upwardly relative to the main body portion to provide a dam for restraining excessive forward flow of body exudate, said absorbent bandage including longitudinally extending means in said absorbent pad for imparting an upwardly concave bias to said absorbent pad in the transverse direction, and a transversely oriented discontinuity in the forward extension of said bottom sheet proximate to the forward edge of the main body portion of said absorbent pad, whereby normal in-use tension on said forward and rearward bottom sheet extensions in cooperation with the reduced overall width toward the rearwardmost end of said absorbent pad and the aforesaid longitudinally extending means for imparting bias causes said absorbent pad to assume an upwardly concave conformation in both the longitudinal and the transverse directions, thereby forming, in cooperation with the forward extension of said absorbent pad, a close-sided, cupped receptacle about the vulva for the collection and retention of body exudate.

15. The absorbent bandage of claim 14, wherein said absorbent pad has a maximum width of between about 2 inches and about 3 inches, said width tapering to between about 1/2 inch and about 1 inch at the rearwardmost end of the main body portion of said absorbent pad and to between about 1/2 inch and about 1- 1/2 inches at the forwardmost end of the forward extension of said absorbent pad, said absorbent pad having an overall length, including said forward extension, of between about 6- 1/2 inches and about 8- 1/2 inches.

16. The absorbent bandage of claim 14, wherein said absorbent pad is comprised of a hydrophilic absorbent core layer of compressed absorbent material having a density throughout of from about 0.22 to about 0.26 gm. per cubic centimeter as measured under a load of 50 gm. per square inch, a 0.05 - 0.06 in. thick by 1.50 in. wide specimen of said absorbent core material having a Taber softness between about 1.2 and about 8.7 gram-centimeters, and a hydrophobic topsheet secured in superposed relation to said absorbent core layer, said topsheet having a density of from about 0.03 to about 0.08 gm. per cubic centimeter as measured under a load of 50 gm. per square inch, said absorbent core layer and said topsheet comprising both the main body portion and the forward extension of said absorbent pad.

17. The absorbent bandage of claim 16, including a thin, flexible backsheet of waterproof material underlying and coextensive with said absorbent core layer, said backsheet being located intermediate said absorbent core layer and said bottom sheet in the area of the main body portion of said absorbent pad and intermediate said absorbent core layer and the overlapping portions of said topsheet in the area of the forward extension of said absorbent pad, said waterproof backsheet thereby preventing strike-through of body exudate absorbed by said absorbent core layer to the lowermost surface of said bandage.

18. The absorbent bandage of claim 16, wherein said hydrophilic absorbent core layer is comprised of compressed airfelt, said hydrophobic topsheet is comprised of non-woven, needle-punched polyester fabric, and said bottom sheet is comprised of hydrophobic, spunbonded, low basis weight, non-woven, polyester fabric.