Patent Application
20090281474
1. Field of the Invention
This invention relates generally to absorbent catamenial tampon pledgets and methods for making such tampon pledgets. More particularly, the present invention relates to tampon pledgets having improved expansion and absorbency characteristics at a withdrawal end to improve leakage protection.
2. Description of the Related Art
The human female vagina is located in the lower pelvic cavity and is surrounded by organs such as the uterus, the bladder, and the rectum. The vagina is a collapsed tube-like structure composed of fibromuscular tissue layers that extends from the uterus inside the body to the vulva on the exterior of the body. The entrance to the vagina, the introitus, is of a relatively small diameter, a lower two-thirds of the vagina is only slightly larger in diameter (if at all) than the introitus, and an upper third (nearest the cervix of the uterus) is the widest diameter. From a biological perspective, the vagina provides a path for fluids to leave the body during the menstruation phase of the menstrual cycle. Imaging data (e.g., magnetic resonance imaging (MRI)) of the pelvic region of women during menstruation shows that women generally place tampon pledgets into one of the vaginal fornices, both anterior and to the right of the cervical os, the source of menstrual bleeding. Both because gravity tends to urge blood down the vaginal cavity toward the exterior of the body and the orientation of the tampon pledget relative to the source of bleeding is typically to high, menstrual blood generally contacts one side of the pledget first, typically close to the withdrawal end of the pledget. Conventional pledgets do not absorb and expand sufficiently rapidly to prevent fluid leakage. Moreover, the typical high placement leads to non-uniform absorbency, which may contribute to bypass leakage. While it is preferable that women insert and position tampon pledget lower in the vaginal cavity (e.g., underneath the cervical os) to promote more uniform absorbency, it is believed that discomfort is experienced by the wearer when the tampon is located closer to the introitus. For example, conventional tampon pledgets may exert greater force on the walls of the vagina near the introitus, as the introitus is of a smaller diameter. Also, nerve endings are present in greater number near the introitus and thus may be irritated by the pressure exerted from the tampon. Finally, near the introitus the vaginas of many women are observed to exhibit a sort of “dog-bone” geometry: narrow in the middle and wider at the ends. Insertion of the tampon in this narrow, middle section can be uncomfortable. This anatomical feature, too, no doubt encourages women to place the tampon up one side, usually to the right, anterior side, as we have noted above.
As noted above, tampon pledget placement within the vaginal cavity can contribute to poor leakage performance. While conventional tampon pledgets are highly absorbent, menstrual fluid can bypass a significant portion of the tampon pledget, causing bypass leakage with only a fraction of the potential tampon absorbency being utilized. For example,
The inventors conducted investigations to confirm that the pattern of absorbency seen in
Moreover, the inventors have discovered that application of image analysis software to MRI data provides a means to examine an anatomical structure of the female vaginal cavity interacting with a feminine hygiene product, such as a tampon, inserted therein. Modeling and analyzing the interaction of the anatomical structure and the product allows the inventors and like product designers a realistic view of the internal workings of the body. For example,
Accordingly, it has been discovered that there is a need for an improved tampon pledget design and, in particular, for a tampon pledget that expands rapidly and has greater absorbency near the withdrawal end of the tampon.
The present invention is directed to a feminine hygiene product. The feminine hygiene product includes a body having a mass of compressed fibrous material, an insertion end and a withdrawal end. The body has an overall length L. The insertion end has a diameter A and the withdrawal end has a diameter B. In an initial state, diameter B is at least one of equal to up to about ten percent greater than the diameter A. When exposed to a fluid, diameter B radially expands such that a ratio of diameter B to diameter A is about 1.25 to 1.
In one embodiment, the diameter A is a smallest diameter of the body within an upper five percent (5%) of the overall length L. In another embodiment, the diameter A is a smallest diameter of the body within an upper fifty percent (50%) of the overall length L.
In one embodiment, the diameter B is a widest diameter of the body within a lower fifty percent (50%) of the overall length L. In one embodiment, the ratio of the diameter B to the diameter A is in a range of about 1.1-3.0 to 1.
In yet another embodiment, the insertion end and the withdrawal end are formed of different fibrous materials. In one embodiment, the different fibrous materials are comprised of at least one of materials having a different fiber composition, a different web density, a different fiber denier, a different fiber finish and/or are formed using a different method of binding together fibers in a non-woven web. In still another embodiment, the fibrous material at the withdrawal end of the body is comprised of a material having at least one of a faster absorbency rate and a larger absorbency capacity than the material of the insertion end of the body.
The features and advantages of the present invention will be better understood when the Detailed Description of the Preferred Embodiments given below is considered in conjunction with the figures provided.
In these figures like structures are assigned like reference numerals, but may not be referenced in the description of all figures.
The inventors discovered that a pledget with increased absorption and/or expansion properties near the withdrawal end of the pledget is beneficial for leakage protection. The inventors also discovered that an essentially cylindrical tampon pledget provides comfort that consumers prefer.
As described above, the diameters B, B′ and B″ (hereinafter referred to collectively as diameter B) increase due to early fluid absorption in the wet environment of the female vagina, which results in the tampon sealing or plugging the vaginal cavity sufficiently and quickly enough to prevent early bypass leakage. In one embodiment, the diameter B expansion is due both to an absorbency rate as well as an absorbent capacity. That is, the withdrawal end 204 of the tampon pledget (e.g., the diameter B portion) is comprised of material having a faster absorbency rate and, in one embodiment, also having a larger absorbent capacity then material comprising the insertion end 202 of the tampon pledget 200 (e.g., the diameter A portion). As illustrated in
The inventors have discovered that to achieve the rapid expansion and formation of a sealing shape (e.g., achieve the diameter B) near the withdrawal end, changes in fibrous materials, non-woven webs, web manufacture, and/or tampon forming methods are employed. For example, the withdrawal end 204 of the pledget 200 is less compressed than the middle and insertion end 202 of the pledget 200. In one embodiment, different compression techniques are employed when forming the insertion versus the withdrawal ends of the pledget. For example, a special crimping tool or a special two-part oven tube is used that is designed to provide more compression in the top two-thirds of the pledget (e.g., at the insertion end) than in the bottom third (e.g., at the withdrawal end). Moreover, a crimping tool or oven tube is tapered or splined to provide an aesthetically pleasing shape. It is also within the scope of the present invention to apply heat and/or pressure differentially when forming the insertion versus the withdrawal ends of the tampon.
For example, an oven tube having an inner diameter that increases from an inside diameter of, say, 13 mm near the top and middle to an inside diameter of, say, 15 mm near the bottom or withdrawal end could be used to make pledgets of this invention. Furthermore, by applying slightly less infrared heating to the bottom or withdrawal end as opposed to that applied to the middle and top portions, one could get the pledget to take a compression set more near the top and encourage the pledget to expand more rapidly and to a greater extent near the withdrawal end. Such differential expansion should help plug up the bottom portion of the vaginal vault and thus reduce bypass leakage. One way to implement this would be to use heating elements to heat up the oven tube to, say, 270 deg F. near the top and middle portions, but keeping the bottom portion cooler, say, by heating only to about 210 deg F.
In one embodiment, the insertion end 202 is formed of different fibers or fibrous web than are used at the withdrawal end 204. For example, at the withdrawal end 204 of the pledget 200, a higher denier, rayon/PET fibrous web provides rapid wicking and, thus, more rapid expansion as compared to a lower denier cotton web, which the inventors have found to be more suitable for the insertion end 202 of the pledget 200. Several non-woven web pieces together provide greater thickness and/or a higher diameter in the bottom third of the pledget (e.g., at the withdrawal end). It should be appreciated that by changing the fiber composition, by changing the web density, by changing the method of binding together fibers in the non-woven web, and/or by changing the fiber denier or fiber finish, the pledget 200 responds to fluid intake more quickly in one portion of the pledget, e.g., at the withdrawal end 204 (e.g., the bottom third of the length), than in the insertion end 202 (e.g., the top two-thirds of the length) of the tampon pledget 200.
It should be appreciated that the present invention also incorporates design principals that are used in conventional tampon pledget designs. For example, the inventive tampon pledgets may be a digital or applicator-type tampons. Moreover, the inventive tampon pledgets include absorbent fibers such as, for example, rayon, cotton, cellulosic fluff, pulp, and the like, as the primary absorbent means. It is also within the scope of the present invention to include super-absorbent and fiber blends involving non-absorbent fibers. Also, tampons of the present invention may optionally include overwrap and/or coverstock, both to prevent fiber sloughing as well as to provide a smooth, comfortable feel. In one embodiment, strings 206 coupled to withdrawal end 204 include a coated cotton fiber.
The inventors have found a number of useful methods for making tampon pledgets of the present invention. For example, the inventors have discovered that methods for making tampon pledgets configured and operating in accordance with the present invention may be folded, radially compressed, cross-pad, non-woven based pledgets using methods similar to those employed to make tampons sold by the assignee of the present invention within its GENTLE GLIDE® brand tampon pledgets. While the manufacturing methods may be similar, when making the inventive tampon pledgets a number and/or dimensions of absorbent pads used prior to compression are varied. For example, pads of the present invention are selected such that when the tampon pledget is formed by folding and subsequent compression, the pledget includes a slightly larger percentage of mass (e.g., higher absorbency) in the withdrawal end of the pledget. In one embodiment, a dimension that is changed within the inventive pledget design as compared to convention design is at least one of the length, width and thickness of a web piece used to produce the two crosspads. In one embodiment, a different density is used for the two web pieces to influence the absorbency and/or the absorbency rate. This is done by both or either using fibers exhibiting different absorbencies and/or by changing the methods of bonding or compressing the non-woven webs used in the pads. For example, if the web is bonded together using needle punching, a higher concentration of needles could be used to influence the web density.
It should be appreciated that it is within the scope of the present invention for the manufacturing parameters outlined above, e.g., use of a different number of pads, pad lengths, pad widths, pad thicknesses, pad basis weights, and fiber materials and blend compositions used to make up the pads, to change together or individually. Table 1 illustrates exemplary pad configurations used to manufacture a tampon pledget in accordance with one embodiment of the present invention.
As illustrated in Table 1, variation is seen in pad lengths and widths for the two pads (e.g., inner and outer) used to make the tampon pledget configurations. The dimensional changes produce pad weight changes but, as is shown in Table 1, the total weight of both pads remain the same, e.g., 3.45 grams. In manufacturing the pledgets identified in Table 1, the same fiber (e.g., a Galaxy® brand multilobal rayon fiber, available from Kelheim Fibres GmbH, of Kelheim, Germany) was used to make the web pieces that make up these pads. Also the web basis weights were substantially the same. The tampon pledgets were folded and formed using an HP simulator machine available from, for example, Hauni Richmond, Inc., Richmond, Va., USA. Oven tubes used to form the cylindrical pledgets, and temperatures and times for heating and compressing the pledgets were nearly identical for these two sets of tampons. In one test scenario, approximately forty (40) tampons were made for each of the configurations listed in Table 1. In one embodiment, GENTLE GLIDE™ brand applicators were used to assemble applicator tampons.
The inventors performed testing to evaluate the tampon pledget configurations illustrated in Table 1. A cutting device such as, for example, a deli slicer (e.g., a Chef's Choice International Electric Food Slicer Model #662, available from Edgecraft Corporation, Avondale, Pa., USA), was used to cut each of the tampon configurations along an axis running lengthwise through the tampon. Once cut, the tampon was examined to determine how the weight was distributed for the two configurations of tampons of Table 1. Several slices were then grouped together to form four “quartiles”. Because the deli slicer cuts almost perfectly uniform slices, these quartiles are of nearly equal length along the longitudinal pledget axis. The slice weights were determined and percentages for each quartile were determined for these two sets of tampons. Table 2 provides weight distribution comparisons. Within Table 2, quartile 1 is closest to the withdrawal or string end.
As is shown in Table 2, Example 1 exhibits a greater percentage of mass near the string or withdrawal end (Quartile 1) versus the Comparative Example (e.g., 10.33% as compared to 7.73%). While the percentage of mass is not a large difference, the inventors have discovered that the percentage of mass is adjusted by other types of pledget changes suggested above. For example, variations in pad thickness and fiber materials in addition to the variations in pad length and widths illustrated in Tables 1 and 2.
The inventors conducted further tests, including syngyna absorbencies, to determine absorbency characteristics for the two configurations of tampon pledgets of Table 1. The results are provided in Table 3.
As is illustrated in Table 3, there are slight differences in the pledget weights and the actual weights were higher than a 3.45 gram target. The dry weights, wet weights and absorbencies are slightly different, but the grams per gram absorbencies are 5.13 (comparative) and 5.19 (Example 1), which are comparable and not statistically significantly different (P=0.128 by the t test).
Table 4 below includes comparisons of measured pledget diameters near the string end for the two configurations of tampon pledget of Table 1, illustrating results both for pledgets before expansion by the syngyna test and for those that had expanded during the syngyna absorbency testing. As is illustrated in Table 4, the tampon pledgets of the present invention expanded at the string end, on average, to a greater extent (a 70.7% diameter increase) than those for the comparative example (a 55% diameter increase). When the data for the two pledgets of Table 1 are compared for all five pledgets at both orientations, results for the expanded diameters are statistically significantly different, based on a two-tailed T test at ninety-five percent (95%) confidence, even though the gram per gram absorbencies are not significantly different.
The results depicted in Table 4 show that the inventive tampon pledgets expand to a greater extent near the string or withdrawal end, as is desired. Given the in-body, computational and laboratory results provided earlier, the inventors realized that such tampon pledget configurations are preferable from both a comfort and leakage protection standpoint.
Although described in the context of preferred embodiments, it should be realized that a number of modifications to these teachings may occur to one skilled in the art. Accordingly, it will be understood by those skilled in the art that changes in form and details may be made therein without departing from the scope and spirit of the invention.
