TAMPON WITH ANGLED FIBER ORIENTATION

Abstract: A tampon is provided which includes absorbent material formed from a pad of at least one layer of fibers. The fibers have an orientation that is predominantly at an angle to the longitudinal centerline of the pad. In one embodiment, the pad is formed of several layers of fibers, and the fiber orientation in each layer of the pad is such that about at least 75 % of the fibers are oriented at an angle between about 35 degrees and about 55 degrees relative to the longitudinal centerline of the pad. Preferred fiber orientations are about 45 degrees relative to the longitudinal centerline of the pad. The pad may be overwrapped, provided with a withdrawal cord sewn across the middle of the pad, and compressed.

Description: TAMPON WITH ANGLED FIBER ORIENTATION FIELD OF THE INVENTION This invention relates to catamenial tampons, and more particularly to a tampon made from a nonwoven pad comprised of diagonally-oriented fibers which is preferably provided with a sewn cord, overwrapped, and compressed. BACKGROUND OF THE INVENTION Tampons are generally formed by providing a mass or batt of nonwoven absorbent fibers predominately aligned longitudinally, overwrapping the mass of fibers, cutting the overwrapped nonwoven mass of fibers to form a rectangular pad, providing a withdrawal cord which is sewn across the middle of the pad perpendicular to the fiber alignment and across sufficient fibers to permit withdrawal, and compressing the sewn overwrapped nonwoven pad parallel to the cord orientation and then perpendicular to the cord. The overwrapping is typically an outer covering of a liquid permeable material, which is designed to improve the lubricity of the tampon, to reduce insertion and withdrawal forces, and to prevent fibers of the mass of fibers from being detached (or "fiber fluff- ofF') during insertion and withdrawal. Examples of tampons made in this manner are described in U.S. Patent 3,058,468 issued to Griswold, et al. on October 16, 1962 and U.S. Patent 3,371,666 issued to Lewing on March 5, 1968. One problem which may occur is the peeling back of the overwrap from the surface of the absorbent nonwoven material during compression. This may occur since the overwrap is open at the cut sides of the rectangular pad, the sides parallel to the sewn cord. The exposed absorbent may cause discomfort and disturb the user, and may result in absorbent fibers being detached ("fiber fluff-off') during insertion and withdrawal of the tampon by a user. SUMMARY OF THE INVENTION This invention relates to catamenial tampons, and more particularly to a tampon made from a nonwoven pad comprised of diagonally-oriented fibers which is preferably provided with a sewn cord, overwrapped, and compressed. The tampon of the present invention is formed by providing a nonwoven mass or batt of layers of absorbent fibers with the fibers oriented diagonally across each layer. The fibers can be oriented at any suitable angle. The fibers are preferably arranged with about 75% of the fibers oriented so that they form an angle of between about 35 and about 55 degrees with the withdrawal cord. In especially preferred embodiments, the fibers are oriented at an angle of approximately 45 degrees across each layer, alternating the fiber orientation of successive layers. The tampon is preferably formed by overwrapping the mass of fibers (sometimes referred to as a "pledget"), cutting the overwrapped nonwoven layered mass of fibers, to form a substantially flat and generally rectangular pad, providing a withdrawal cord sewn across the middle of the pad perpendicular to the cut sides of the pad, compressing the sewn overwrapped nonwoven layered pad parallel to the cord orientation and perpendicular to the cord orientation. The tampon of the invention deploys with increased lateral and/or radial expansion and decreased longitudinal expansion resulting from the angle of the compressed fibers not being predominately perpendicular to the axis of the tampon; in some cases, reducing leakage without causing discomfort and disturbing the user. In one embodiment, the tampon comprises an absorbent pad with overwrapping disposed continuously around the generally rectangular pad from end to end, but the overwrapping is open at the cut sides of the rectangular pad, the sides parallel to the sewn cord. In preferred embodiments of the invention, the tampon has a continuous overwrap around the circumferential surface and the cut sides of the overwrapped pad are at the ends. In other preferred embodiments of the invention, the overwrap is overlapped in the middle of the pad and the withdrawal cord is sewn on the pad through both laps of the overwrap which secures the overwrap in place without the hard spots on the tampon which may result from bonding of the overwrap to the absorbent material. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is an exploded perspective view which shows four layers of nonwoven absorbent material with alternating fiber orientation used to make one preferred embodiment the tampon of the present invention. Fig. 2 is a schematic perspective view of the four layers assembled into a pad with a withdrawal cord sewn onto the pad without an overwrap. Fig. 3 is a perspective view of one embodiment of the invention with the assembled pad overwrapped open at the sides and with a withdrawal cord sewn onto the pad. Fig. 4 is a perspective view of another embodiment of the invention with the assembled pad overwrapped open at the ends and with a withdrawal cord sewn onto the pad. Fig. 5 is a perspective view of the embodiment shown in Fig. 4 after it has been compressed into a tampon. DETAILED DESCRIPTION OF THE INVENTION This invention relates to catamenial tampons, and more particularly to a tampon made from a nonwoven pad comprised of diagonally-oriented fibers which is preferably provided with a sewn cord, overwrapped, and compressed. A preferred tampon and the stages for making the tampon of the present invention is illustrated by Figs. 1, 4 and 5. Fig. 1 shows several nonwoven layers of fibers that are used to make a preferred embodiment of the tampon of the present invention. There are generally four rectangular layers of nonwoven material shown in Fig. 1. These are designated 22, 24, 26, and 28. Each of the nonwoven layers comprises a plurality of fibers, designated 23, 25, 27, and 29, respectively. The fibers preferably comprise cotton, rayon, or blends thereof. The layers 22, 24, 26, and 28 are preferably formed by carding the fibers, however, other suitable processes can be used. It should be understood that the fibers are shown schematically in a very regular and orderly arrangement in Fig. 1 for purposes of illustration. In an actual tampon, the fibers will typically be smaller in diameter, and more random in orientation and will often have a degree of waviness along their length, rather than being perfectly linear as shown. The fibers 23, 25, 27, and 29 in the nonwoven layers are predominantly oriented diagonally relative to the longitudinal centerline L of the generally rectangular layers (and the pad into which the layers are formed). The longitudinal centerline of the rectangular layers will typically coincide with the location of the withdrawal cord. The longitudinal centerline L will also typically be parallel to the longitudinal side edges of the rectangular layers. The fibers 23, 25, 27, and 29 can form any suitable angle with the longitudinal centerline L. It should be understood that carded fiber strands cannot be formed with an extremely high degree of precision. Thus, each layer will have some fibers in all possible orientations. The term "predominantly" as used herein, refers to the fact that a general orientation of the fibers can be detected. Preferably, the fibers in each layer are predominantly oriented at an angle of between about 35 degrees and about 55 degrees relative to the longitudinal centerline L. Preferably, at least about 75% of the fibers in each layer are oriented at an angle of between about 35 degrees and about 55 degrees relative to the longitudinal centerline L. In especially preferred embodiments, at least about 75% of the fibers in each layer are oriented at an angle of about 45 degrees relative to the longitudinal centerline L. The nonwoven layers can be formed with the fibers oriented diagonally in any suitable manner. For example, the rectangular layers can be cut from a larger nonwoven web at an angle (or on a "bias") relative to the orientation of the fibers in the larger nonwoven web so that the fibers in the rectangular layers will be at the desired angle. The tampon 20 can be comprised of any suitable number of layers of fibers. The fibers in the different layers can all be aligned in the same general direction and at the same angle relative to the longitudinal centerline L. Alternatively, the fibers in the layers can be oriented in different directions at the same angle or at different angles relative to the longitudinal centerline L. In other embodiments, the fibers in the layers can be oriented in the same general direction, but at different angles relative to the longitudinal centerline L. Fig. 1 shows an especially preferred embodiment in which the absorbent material in the top layer 22 has a fiber orientation of about 45 degrees relative to the longitudinal centerline L. The fibers 23 in layer 22 are oriented at a 45 degree angle turned in a counter clockwise direction from the longitudinal centerline L. The fibers 25 in the second layer 24 have an orientation that is also 45 degrees relative to the longitudinal centerline L of that layer, but the 45 degrees angle is turned in a clockwise direction from the longitudinal centerline L. Thus, the angle of the fibers 25 in the second layer 24 are offset 90 degrees from the angle of the fibers 23 in the top layer 22. The orientation of the fibers 27 in the third layer 26 is the same as that of the first layer 27. The orientation of the fibers 29 in the fourth layer 28 is the same as that of the second layer 24. In a preferred embodiment, the tampon of the present invention is made by compressing a sewn overwrapped pad comprised of equal layers of absorbent material where the fibers in alternating layers are in opposite 45 degree orientations. The layers of fibers 22, 24, 26, and 28 are preferably formed into a substantially flat, generally rectangular pad 30 as shown in Fig. 2. It should be understood, however, that the tampon of the present invention is not limited generally flat or rectangular pads, and the angled fiber orientation can be utilized in other tampons, including those that are not substantially flat or generally rectangular. The preferred pad 30 shown in the drawings, however, is preferably generally rectangular, and has a pair of longitudinal side edges 32 and a pair of end edges 34. In the preferred embodiment shown in the drawings, the longitudinal side edges 32 are longer than the end edges 34. The flat pad 30 preferably has a withdrawal cord 36 joined thereto by stitching, such as with a thread 38. The withdrawal cord 36 preferably extends axiably along the longitudinal centerline L of the layers beyond one of the end edges 34 thereof. The flat pad 30 can then be comprised into a tampon in conventional manner, or it can be provided with an overwrap and then compressed. The absorbent pad material preferably has a basis weight of between about 240 g/m 2 and about 1,000 g/m 2 . Numerous embodiments of the present invention are possible. For example, the pad that is made into the tampon need not be rectangular. In other embodiments for example, the pad can have a chevron-shaped plan view. In another embodiment, the tampon can be made of absorbent material which is carded, cross-lapped, and drafted to achieve the angled fiber orientation, and then is preferably needle punched, slit into ribbon, overwrapped, cut into rectangular pads, sewn with a withdrawal cord and compressed. The carded cross-lapped web will typically have fibers oriented at an angle of between about 15-20 degrees relative to the cross machine direction (a direction perpendicular to the longitudinal centerline, L). The drafting process straightens the angle of the fibers relative to the machine direction. After the cross-lapped material is drafted, the angle of the fibers is typically between about 35-50 degrees, and is preferably about 45 degrees. The drafting to achieve 45 degree orientation with alternating layers of opposite orientation can be made with the Asselin Octoweb Drafter, manufactured by N. Schlumberger & Cie, Guebwiller Cedex, France. Needle punching is used to stabilize the cross-lapped nonwoven web. The layers of fibers can be provided with an overwrap 40 which is folded around the ends 34 of the layers as shown in Fig. 3. The overwrap 40 can be comprised of any material known as being suitable for this particular purpose. The overwrap 40 is preferably comprised of a nonwoven material having a basis weight of between about 10 g/m 2 and about 20 g/m 2 . In a preferred embodiment, the overwrap 40 is folded around the sides 32 of the layers and is secured by overlapping and by the sewing on of the withdrawal cord 36 and is illustrated by Fig. 4. In other embodiments, one or more overwraps can be used to wrap around both the sides and the ends of the pad 30. Fig. 5 shows the preferred overwrapped pad 30 shown in Fig. 4 which has been compressed longitudinally and transversely to form the finished tampon 20. The tampon can be inserted into the wearer's vaginal cavity digitally, or with the use of an applicator. The tampon is preferably placed in an applicator for insertion into the wearer's vaginal cavity. The applicator can be of the open end type, or a closed end type. Examples of suitable applicators are described in U.S. Patent 5,346,468 issued to Campion, et al. on September 13, 1994, and U.S. Patent 5,558,631 issued to Campion, et al. on September 24, 1996, both of which are assigned to Tambrands, Inc. The disclosures of all patents, patent applications (and any patents which issue thereon, as well as any corresponding published foreign patent applications), and publications mentioned throughout this patent application are hereby incorporated by reference herein. It is expressly not admitted, however, that any of the documents incorporated by reference herein teach or disclose the present invention. It is also expressly not admitted that any of the commercially available materials or products described herein teach or disclose the present invention. While particular embodiments of the present invention have been illustrated and described, it would be obvious to those skilled in the art that various other changes and modifications can be made without departing from the spirit and scope of the invention.

Claims: What is claimed is: 1. A tampon pledget for a tampon adapted for insertion into a body cavity, said tampon pledget comprising an absorbent pad formed of at least one fibrous layer, said at least one fibrous layer having a longitudinal centerline, and comprising a plurality of fibers having an orientation predominantly at an angle to the longitudinal centerline of said at least one fibrous layer. 2. The tampon pledget of Claim 1 wherein at least about 75% of the fibers in said at least one fibrous layer are oriented at an angle of between about 35 degrees and about 55 degrees relative to the longitudinal centerline. 3. The tampon pledget of Claim 1 wherein the fibers in said at least one fibrous layer are predominantly orientated at an angle of about 45 degrees relative to the longitudinal centerline. 4. The tampon pledget of Claim 1 comprising two or more fibrous layers. 5. The tampon pledget of Claim 4 wherein the fibers in each layer are oriented at the same general angle. 6. The tampon pledget of Claim 4 wherein the fibers in at least two different layers are oriented at different angles. 7. The tampon pledget of Claim 4 wherein the fibers in at least one of said fibrous layers are predominantly oriented at an angle of about 45 degrees relative to the longitudinal centerline turned in a counterclockwise direction from the longitudinal centerline, and the fibers in at least one of the layers are predominantly oriented at an angle of about 45 degrees relative to the longitudinal centerline turned in a clockwise direction from the longitudinal centerline. 8. The tampon pledget of Claim 1 wherein said absorbent pad is substantially rectangular. . The tampon pledget of Claim 1 wherein said absorbent pad is chevron-shaped. 10. The tampon pledget of Claim 1 wherein said absorbent pad has a basis weight of from about 250 g/m 2 to 1,000 g m 2 . 11. The tampon pledget of Claim 1 wherein said absorbent pad has a pair of longitudinal side edges and a pair of end edges, said tampon pledget further comprising an overwrap wrapped around at least the end edges of said absorbent pad. 12. The tampon pledget of Claim 1 wherein said absorbent pad has a pair of longitudinal side edges and a pair of side edges, said tampon pledget further comprising an overwrap wrapped around at least the side edges of said absorbent pad. 13. The tampon pledget of Claim 12 further comprising a withdrawal cord wherein said overwrap comprises portions that overlap, and said portions that overlap are held by the sewing of the withdrawal cord onto the absorbent pad over the entire length of the overlap. 14. A tampon adapted for insertion into a body cavity comprising the tampon pledget of Claim 13 wherein the orientation of the fibers in said tampon pledget is at an angle of about 45 degrees to the cord, and said tampon pledget is compressed. 15. The tampon of Claim 14 wherein said fibers are selected from the group consisting of cotton fibers, rayon fibers, and blends thereof. 16. The tampon of Claim 14 wherein the overwrap, sewing thread and withdrawal cord are selected from the group consisting of cotton, rayon, and blends thereof. 17. The tampon of Claim 14 wherein the overwrap has a basis weight of from about 10 g/m 2 to 20 g/m 2 .

Applicants: CURTIS JON ARTHUR, PROCTER & GAMBLE, CURTIS, JON, ARTHUR, THE PROCTER & GAMBLE COMPANY
Application year: 1999
Main classification: A61F13
IPC codes: A61F13