Abstract:
A tampon pledget has an absorbent mass of material and a withdrawal string located at one end thereof. During use, the tampon pledget expands to take on a geometric configuration that approximates the shape of the vagina into which the tampon pledget is inserted. An anthroprometrically expandable tampon pledget has an absorbent mass of material that is defined by a first end having a first density, a second end having a second density, and a portion intermediate the first and second ends. The material expands at different rates upon being contacted by body fluids, thereby allowing the tampon pledget to conform to the shape of a vagina. A method of making an expandable tampon pledget includes the steps of providing an absorbent material, attaching a string thereto, and compressing the material into a cylindrical shape such that a density gradient is realized over a length of the compressed material.

Description:
TECHNICAL FIELD 
       [0001]    The present invention generally relates to tampon pledgets and, more particularly, to tampon pledgets that expand in the vaginal canal in response to the absorption of body fluids. 
       BACKGROUND OF THE INVENTION 
       [0002]    In female placental mammals, particularly humans, the vagina is an elastic muscular canal that extends from the uterus inside the body to the vulva on the outside the body. The narrow lower neck of the uterus forms the cervix. The entrance to the vagina is known as the introitus and is located at the back end of the vulva. 
         [0003]    Although there is wide anatomical variation, the average length of the canal from the introitus to the cervix is about 3 to 5 inches. The introitus is of a relatively small diameter, and the bottom two-thirds of the vagina is only slightly, if at all, wider than the introitus. The transverse (side-to-side) width in the bottom two-thirds portion is typically slightly larger than the front-to-back width, which is especially small. The vagina is widest in its upper one-third portion nearest the cervix. The elasticity of the walls of the canal that forms the vagina allows it to stretch as needed. When the vagina is in a relaxed state, the walls thereof typically collapse on each other but can be opened up slightly with minimal pressure. 
         [0004]    From a biological perspective, the vagina provides a path for fluids to leave the body during the menstruation phase of the menstrual cycle. The menstrual cycle is a recurring cycle of physiological changes in females that is associated with reproductive fertility. The menstruation phase of the menstrual cycle involves the shedding of the uterine lining. During this shedding, tissue and blood is exuded from the uterus. 
         [0005]    In modern cultures, disposable absorbent devices have been used for the capture and absorption of material, particularly the blood, exuded during the menstruation phase. These devices include external-use sanitary towels or napkins and internal-use devices such as tampon pledgets. Other devices such as internally-worn cups are also known but not in wide use today. 
         [0006]    Tampon pledgets generally comprise non-woven webs of absorbent materials such as rayon, cotton, combinations of the foregoing, and/or other materials in fiber form. These webs are typically stacked such the interfacial areas thereof are bonded together. The stacked and bonded webs are then folded, pleated, and/or rolled to approximate the desired geometry, which is typically a generally cylindrical shape. One end of a string is incorporated into the web material, which is then compressed to a final shape. The string functions as a means of withdrawing the tampon pledget from the vagina after the useful life of the tampon pledget. A coverstock may be located over the compressed absorbent materials to maintain the cylindrical shape and/or to provide increased comfort during the insertion and removal of the tampon pledget. The tampon pledgets are then optionally inserted into a cardboard or plastic applicator device and packaged. 
         [0007]    When inserted into the vagina and expanded, such conventional tampon pledgets are generally sufficient to accommodate differences in menstrual flow patterns for the vast majority of women. However, the differences in anatomical structure of women oftentimes results in a less than optimal conformance to the vaginal shape. When the tampon pledget does not conform to the vaginal shape, the likelihood of flow of body fluids from the cervix, around the tampon, and to the introitus is increased. Many conventional tampon pledgets generally conform to the shape of the vagina. However, the shapes of such pledgets are determined and attained prior to contact of the material by the body fluids. 
         [0008]    Based on the foregoing, it is an object of the present invention to provide a tampon pledget that expands when contacted by body fluids to more closely approximate the shape of the vagina to prevent or at least minimize the likelihood of leakage of body fluids from the vagina. 
       SUMMARY OF THE INVENTION 
       [0009]    In one aspect, the present invention resides in a tampon pledget having an absorbent mass of material and a withdrawal string located at one end thereof. The tampon pledget is initially cylindrical in shape. During use and upon contact with menses or other body fluids, the tampon pledget expands to take on a geometric configuration that approximates the shape and configuration of the vagina into which the tampon pledget is inserted. This expansion results largely from the density distribution of the materials utilized to form the tampon pledget. Preferably, the tampon pledget expands to form an hourglass-shaped member that provides suitable contact with the vagina walls. The upper portion of the hourglass shape absorbs the bulk of the menses or other body fluid, while the middle portion and the lower portion proximate the introitus also contact the walls of the vaginal cavity to absorb any menses or other fluid that may have bypassed the upper portion. 
         [0010]    In another aspect, the present invention resides in an anthroprometrically expandable tampon pledget having an absorbent mass of material that is defined by a first end having a first density, a second end having a second density, and a portion intermediate the first and second ends. This intermediate portion has a third density that is different from at least one of the first density and the second density. The differences in densities allow the material of the mass to expand at different rates upon being contacted by body fluids, thereby allowing the tampon pledget to conform to the shape of a vaginal cavity. The tampon pledget also has means for withdrawing the tampon pledget from the vaginal cavity (such as a string). The absorbent mass of material is cylindrical in shape. 
         [0011]    In another aspect, the present invention resides in a method of making an expandable tampon pledget. This method includes the steps of providing at least one absorbent material, attaching a string thereto, and compressing the absorbent material into a final cylindrical shape such that a density gradient is realized over a length of the compressed absorbent material. A density gradient defined along the length of the tampon pledget allows it to anthroprometrically expand to the shape of a vaginal cavity into which it is inserted upon contact with body fluid. 
         [0012]    Although the conformance of the shape of the tampon pledget to the vaginal cavity allows for the absorption of fluid while minimizing leaking to the introitus, several other advantages will become apparent. First, such a configuration provides optimal comfort to the user. In particular, because the tampon pledget expands to contact the walls of the vagina, it exerts pressure in the radial directions, thereby allowing the tampon pledget to be securely held in the vaginal canal. This provides an improved level of comfort to the user, particularly in instances in which the user is physically active. 
         [0013]    Second, the cylindrical shape of the tampon pledget is relatively inexpensive and easy to manufacture. Tooling apparatus and manufacturing processes, particularly those related to compressing the pledget material into the pre-expanded shape, can be simple in design. 
         [0014]    Third, because the pledgets of the present invention are initially cylindrical rather than curved or serpentine in shape, only a minimal amount of force is required to eject these tampon pledgets from convention tampon pledget applicators (which are typically cardboard or plastic). Thus, the tampon pledgets of the present invention may be used with existing applicators, and no new tooling or design considerations are necessary. 
         [0015]    These and other advantages of the present invention will become apparent to those of skill in the art from the following description of the preferred embodiments. 
     
    
     
       DESCRIPTION OF THE DRAWINGS 
         [0016]      FIG. 1  is a schematic representation of a tampon pledget of the present invention. 
           [0017]      FIG. 2  is a schematic representation of the tampon pledget of  FIG. 1  in an expanded state. 
           [0018]      FIG. 3  is a schematic representation of a first rolled web around the ends of which second webs are rolled to form an absorbent mass of a tampon pledget of the present invention. 
           [0019]      FIG. 4  is a schematic representation of layers of webs of alternating sizes for subsequent rolling to form an absorbent mass of a tampon pledget of the present invention. 
           [0020]      FIG. 5  is a perspective view of a tampon pledget of the present invention. 
           [0021]      FIG. 6  is a graphical representation illustrating how various portions of the tampon pledget of the present invention change during use to anthroprometrically conform to the shape of a vaginal canal. 
           [0022]      FIG. 7A  is an MRI scan of a tampon pledget in a vagina. 
           [0023]      FIG. 7B  is an MRI scan of a tampon pledget in a vagina. 
           [0024]      FIG. 7C  is an MRI scan of a tampon pledget in a vagina. 
           [0025]      FIG. 8  is a perspective view of a cone-shaped tampon pledget of the present invention. 
           [0026]      FIG. 9  is a perspective view of a serpentine-shaped tampon pledget of the present invention. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0027]    As shown in  FIGS. 1 and 2 , a tampon pledget of the present invention is generally designated by the reference numeral  10  and is hereinafter referred to as “pledget  10 .” The pledget  10  includes an absorbent mass  12  of suitable material. An insertion end  16  is located at one end of the absorbent mass  12 , and a withdrawal end  18  is located at an opposing end of the absorbent mass. A removal string  20  is incorporated into the absorbent mass  12  proximate the withdrawal end  18 . The absorbent mass  12  may or may not be sheathed in a coverstock  14  that is capable of allowing the flow of menses or other body fluid therethrough. If the coverstock  14  is included, the removal string  20  can be tied thereto proximate the withdrawal end  18 . 
         [0028]    In its initial form ( FIG. 1 ), the pledget  10  is cylindrical in shape. During use, the pledget  10  expands in response to the absorption of menses or other body fluids to an anthroprometric geometry ( FIG. 2 ) in order to approximate the shape of a vaginal cavity into which the pledget is inserted. As used herein, the phrase “anthroprometric” is intended herein to indicate expandable upon contact with fluid to conform to a bounded area. 
         [0029]    Referring specifically to  FIG. 1 , the absorbent mass  12  is defined by an absorbent material. This absorbent material is generally rayon, cellulosic material such as cotton or paper, or combinations of the foregoing, although other materials are within the scope of the present invention. In one embodiment, the absorbent material is defined by one or more webs  24 . These webs  24  are woven strands of material. In the alternative, the webs  24  may be open-cell foam or sponge. The present invention is not limited to woven strands of material, foam material, or sponge, however, as other forms of the materials such as felts or other non-stranded materials may be used. 
         [0030]    The webs  24  are arranged such that about one third of the absorbent mass  12  proximate the insertion end  16  of the finished pledget  10  has an initial predetermined density. The webs  24  are also arranged such that about one third of the absorbent mass  12  proximate the withdrawal end  18  of the finished pledget  10  also has an initial predetermined density. These two densities, which may or may not be the same, are based on the mass of absorbent material per unit volume and at least one of the particular geometry of the web material used, the method of constructing the pledget  10 , the application of pressure to the absorbent mass  12  to form it to the cylindrical shape, the direction and duration of pressure application, and ambient temperature. 
         [0031]    In one embodiment as shown in  FIG. 3 , the absorbent mass  12  is arranged by combining webs of varying sizes into an approximate initial cylindrical shape. The webs are combined by rolling a first web  24   a  into a cylindrical shape that substantially corresponds to a length L of the pledget  10  and rolling end webs  24   b  around the ends of the rolled first web  24   a . The present invention is not limited to the rolling of webs, as other means of combining the materials (such as folding, gluing, and the like) are within the scope of the present invention. Furthermore, the present invention is not limited to the use of two or more webs, as one web may be rolled or folded to form the approximate initial cylindrical shape. 
         [0032]    In another embodiment as shown in  FIG. 4 , the webs are combined by rolling a plurality of web materials of different sizes. In particular, a plurality of first webs  24   a  that substantially correspond to the length L of the finished pledget are interwound with a plurality of second webs  24   b  that are shorter in a lengthwise dimension and selectively placed proximate the insertion end  16  and the withdrawal end  18  of the finished pledget  10 . 
         [0033]    The present invention is not limited to the combination of webs of varying sizes, as webs of varying shapes and weights may also be used to form the tampon pledget of the present invention. 
         [0034]    In any embodiment, the webs can be produced by combing or carding using a suitable combing or carding device to produce a matte of non-woven fibers. Fibers in this matte can be oriented in a particular direction by, for example, a carding machine and aligned. In the alternative, the fibers can be randomly arranged. By varying the number, distribution, and orientation of absorbing fibers relative to non-absorbing fibers, the density of the matte can be adjusted. 
         [0035]    The fibers can be bound together using any of a variety of techniques. For example, the fibers can be bound using barbed needles in a needletacking process; they can be bound chemically using adhesives, water-dispersible binders, or the like; they can be bound thermally using high temperatures; or they can be bound using a hydroentangling technique using high-pressure water jets. Irrespective of the technique used, the density of the matte can be adjusted during the particular technique. The binding generally prevents the sloughing of fibers in the woman&#39;s vagina. In the alternative, the fibers in the matte can be left unbound, and a second web of non-woven material can be used as a covering to prevent the sloughing of unbound fibers. 
         [0036]    Once the matte has been finally formed, a portion of material is cut therefrom, wound into the approximate shape of a tampon, and cut to the size desired for a specific absorbency range. The material can be rolled up using mechanical means in which the material is wound on itself, or it can be folded into a desired shape (e.g., a “W” shape or the like) using folding rams. Typically, after either rolling or folding, the tampon is compressed into a self-sustaining cylindrical form. In addition to compressive forces, temperature and moisture content may be adjusted to provide the desired cylindrical form. The density of the tampon can also be adjusted by applying compressive forces of differing amounts of pressure. Once in the cylindrical form, the tampon can be combined with a tampon applicator. 
         [0037]    Referring now to  FIG. 5 , once the webs are rolled into the absorbent mass  12  that approximates an initial cylindrical shape, they are compressed into a substantially uniform final cylindrical geometry. Compression of the absorbent mass  12  generally occurs in one or more radial directions to define the sides of the pledget  10 . Compression may also occur in one or both axial directions to define the ends of the pledget  10 . In either case, suitable tooling is used to define the surfaces of the pledget  10 . 
         [0038]    Before the absorbent mass  12  is compressed, a top third portion  30  thereof has a greater initial mass and volume of absorbent material than does a middle third portion  32 . When the absorbent mass  12  is compressed ( FIG. 5  shows the pledget  10  after compression), both the top third portion  30  and the middle third portion  32  have the same final volume of absorbent material, but the absorbent material of the top third portion is more tightly compressed. The top third portion  30  is therefore denser than the middle third portion  32 . A bottom third portion  34  also has a greater initial mass and volume of absorbent material than the middle third portion  32  and, when compressed to the same final volume as the middle third portion, is denser than the middle third portion. Although this disclosure refers to the portions of the absorbent mass as “thirds,” it should be understood that each “third” is not required to be of equal size. Compression of the absorbent material also affects both absorption capacity, i.e., the volume of fluid absorbed, as well as the absorbency rate, i.e., how fast menses or other body fluids are taken up by the tampon. Both affect the expansion characteristics of the pledget  10  during the intake of menses or other body fluids during use. 
         [0039]    After compression in which the top third portion  30  and the bottom third portion  34  are compressed to correspond in cross sectional geometry to the middle third portion  32 , the density varies along the length of the pledget  10  to produce a lengthwise density gradient d L . This lengthwise density gradient d L  enables different portions of the pledget  10  to absorb fluid at different rates and therefore to expand at different rates. In particular, the denser top third portion  30  has a greater potential porosity than the middle third portion  32  and therefore has the potential to expand to a volume that is greater than the volume of the middle third portion  32 . The bottom third portion  34 , which also includes more tightly compressed and therefore denser absorbent material, expands in a manner similar to the top third portion  30 . 
         [0040]    In embodiments in which web materials for the top third portion  30  and the bottom third portion  34  differ from the material of the first web (shown as  24   a  in  FIG. 4 ), a core  40  is defined at the center of the rolled webs and along an axis A. In such an embodiment, the density may be different near the external surfaces of the pledget  10 , thereby producing a radial density gradient d R . Also in such an embodiment, the radial density gradient d R  may be different at various points along the axis A, particularly in the middle third portion  32 . A compression tool or a crimping tool may be utilized to compress or crimp the pledget  10  at various points along the length thereof, thereby causing the radial density gradient d R  to be different at the various points along the pledget. 
         [0041]    Irrespective of whether or not the pledget  10  includes a radial density gradient d R , the geometry of the web material(s), the particular method of construction of the pledget, the application of pressure, the directions (radial and/or axial) of pressure application, the duration of pressure application, and the temperature are all factors in the determination of the ability of the pledget to absorb menses or other body fluids. Collectively, these factors are used to define a density profile of the pledget  10 . 
         [0042]    Once the absorbent mass  12  is compressed into its desired cylindrical form, the coverstock, if desired, can then be located thereover. 
         [0043]    Referring back to  FIG. 2 , the anthroprometric geometry of the pledget  10  during use is shown. As menses or other body fluids enter the pledget  10 , the density profile of the pledget is altered. In particular, as menses and other body fluids are absorbed, variations in the number of pores, pore sizes, and pore size distributions throughout the material of the pledget  10  effect changes in the capillary pressure throughout the pledget itself. These changes in capillary pressure influence the absorption of the fluid considerably, namely, by causing the pledget  10  to expand to the anthroprometric geometry. Particularly because of the differences in density along the length of the pledget  10 , the anthroprometric expansion of the absorbent mass  12  causes the pledget to expand into the shape of the vagina. Preferably, the pledget  10  expands to form an hourglass-shaped object, i.e., wide at the insertion end  16  where the pledget is closest to the cervix, narrower in the middle where the vagina narrows, and slightly widened at the withdrawal end  18  near the introitus. When the pledget  10  is constructed as described above, this expansion occurs rapidly. The hourglass shape develops from the initial onset of fluid and persists until the pledget  10  is removed from the vagina. 
         [0044]    The actual preferred anthroprometric geometry and density profile of the pledget  10  during use depends on several factors. Thus, the particular embodiments of the pledget  10  described herein are not limited to those shown. Factors that may contribute to the anthroprometric geometry of the manufactured pledget  10  and its density profile during use include, but are not limited to, the geometry of the particular vagina in which the pledget is inserted, the absorbency of the material used to construct the pledget, the need for improved leakage protection such as bypass protection, and the need for comfort during the insertion, wearing, and removal of the pledget. Thus, the precise quantitative parameters for optimum geometries and densities can vary. More specifically, the precise quantitative parameters can differ based on whether the pledget  10  is intended for use by, for example, younger women, older women, women who have given birth, or active women. 
         [0045]    Referring now to  FIG. 6 , a graphical representation  50  of the density profile illustrates how the various portions of the pledget change during use to anthroprometrically conform to the shape of the vaginal canal. As can be seen by line  52 , the top third portion of the pledget increases its diameter during fluid absorption from about 3% to about 200% and preferably from about 30% to about 40%. Line  54  illustrates how the middle third portion of the pledget decreases its diameter. This decrease in diameter is due to “necking,” which can be caused by the expansion of adjacent areas to cause the pulling of material from the middle third portion due to variations in the pore size, distribution, and density or by less fiber being located in the middle third portion to begin with, thereby resulting in less expansion. However, although the middle third portion is shown as decreasing in diameter, the present invention is not limited in this regard and the middle third portion may slightly increase in diameter or stay the same. Line  56  illustrates how the lower third portion of the pledget increases in diameter from about 3% to about 200% and preferably from about 10% to about 20%. The most pronounced expansion of the pledget is preferably in the upper third portion in order to limit the bypass of fluid around the upper third portion to the lower portions. The present invention is not limited in this regard, however, as both the upper third portion and the lower third portion may expand approximately the same amount. All of the foregoing percentages are volume/volume percentages (volume of one liquid component per total volume tampon pledget). 
         [0046]    Referring now to  FIGS. 7A through 7C , transaxial cross-sectional views of tampon pledgets in vivo are shown for three different women. In  FIGS. 7A ,  7 B, and  7 C, tampon pledgets in vivo are shown respectively at  82 ,  84 , and  86 . The expansion characteristics for each tampon pledget, which are similar in configuration, are different depending on the shape of the vagina into which the tampon pledget is inserted. During use, tampon pledget  82  is somewhat flattened and conforms to the transverse dimension of the vagina. On the other hand, tampon pledget  84  remains substantially circular in cross-section due to the shape of the vagina of the woman into which that tampon pledget is inserted. Furthermore, tampon pledget  86  approximates an elliptical cross-sectional geometry as a result of the shape of the vagina of the woman into which that tampon pledget is inserted. Such shape changes are influenced by a variety of interdependent factors, namely, the amounts and rates of absorption, the tampon pledget placement in the vagina relative to the source of the bleeding, the cervical os, the amount of pressure exerted by the vaginal muscles, and the particular shape of the vagina. 
         [0047]    Based on the foregoing, actual tampon design and geometry (e.g., density profile, initial tampon shape, and the like) suggest that changes to the design and geometry can affect expansion characteristics. Thus, such data supports the fact that the tampon pledgets of the present invention expand approximately into hourglass shapes, as shown in  FIG. 2 , during use. 
         [0048]    As is shown in  FIG. 8 , a tampon pledget  110  may be fabricated to have an anthroprometric geometry that approximates a goblet or a cone. In such a device, an upper third portion  130  expands significantly in response to the absorption of menses or body fluids to conform to the shape of the vagina. The middle third portion  132  may experience necking, substantially retain its original diameter, or may slightly increase in diameter (as shown). The lower third portion  134  may also experience necking or substantially retain its original diameter. 
         [0049]    As is shown in  FIG. 9 , a tampon pledget  210  may be fabricated to have an anthroprometric geometry that approximates a serpentine shape. In approximating this serpentine shape, the pledget  210  expands during use and upon contact with fluid to have a slight S-shaped configuration to accommodate a vaginal canal having a substantially corresponding shape (front-to-back). In pledget  210 , a middle third portion  232  is slightly smaller in diameter than either a top third portion  230  or a bottom third portion  234 . However, the material of the pledget  210  (e.g., rolled or folded web material) can be located such that upon the absorption of fluid, the top third portion  230  and the bottom third portion  234  are pulled in opposite directions, as shown by arrows  245 , relative to the middle third portion  232 . In the alternative, or additionally, because the material of the pledget  210  often has a “memory” that enables the pledget to “recover” its shape, the S-shaped configuration could be obtained by the process used to manufacture the pledget. 
         [0050]    Although this invention has been shown and described with respect to the detailed embodiments thereof, it will be understood by those of skill in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiments disclosed in the above detailed description, but that the invention will include all embodiments falling within the scope of the appended claims.