MXPA06004885A - A hygienic tampon and an absorbent body used in the formation of a tampon - Google Patents

Abstract

A tampon comprised of a matrix is disclosed, wherein the matrix is provided with an inner surface and a structural layer adjacent to the inner surface, the structural layerbeing constituted of at least one thermosplastic element. An absorbent body, particurlarly used in the formation of a tampon, is also disclosed.

Description

A HYGIENIC TAMPON AND AN ABSORBENT BODY USED IN THE FORMATION OF A TAMPON FIELD OF THE INVENTION The present invention relates to a novel process for manufacturing absorbent tampons that is versatile and useful for producing tampons and novel tampons produced therefrom.

BACKGROUND OF THE INVENTION Two types of hygienic tampons are known, those that require that an apiicador be inserted in the vagina and those that can be digitally inserted. Both tampons present problems with regard to insertion, withdrawal and absorbency, due to the particularities of the anatomy of the vagina. Absorbency capacity problems occur due to some situations, such as the following: tampons do not fit properly to the vagina; the tampons have been compressed to such a degree that they have difficulty opening or expanding rapidly enough after the initial insertion into the vagina to absorb the initial volumes of the body fluid contacting them; The shape of the tampon may not effectively match the structure of the vagina. Therefore, the tampons do not make contact with the entire vaginal wall, creating a possibility of effusion; the tampon does not contain a sufficient amount of absorbent material at its insertion end that is capable of absorbing and completely distributing the body fluid that contacts it. In its normal, folded state, the vagina has a much wider dimension in its transverse plane than in its vertical plane. It is also well known that the area determined by the vaginal cavity is minimal near the introitus and maximal near the neck. It is also flaccid and has multiple folds and wrinkles that provide channels through which a significant portion of menstrual fluids normally flow. Accordingly, the tampon must have a shape that allows it to pass through the vaginal orifice without discomfort, and once inside the vaginal cavity and beyond the orifice restrictions, it may occupy a volume such that it substantially contacts all of the surface of the vaginal walls, particularly the folds and channels mentioned. Said tampon must adapt to the shape of the vaginal cavity or cause the vaginal cavity to take a complete shape, substantially opening these folds and channels.

Examples of patents that appear to describe buffers capable of radially expanding can be seen in the U.S. Patents. 2,499,414; 3,618,605 and 3,834,389. Each of these patents discloses buffers having at least two layers, which require complex manufacturing processes. Each of the tampons also requires a certain degree of compression in order to be inserted into an applicator or into the vagina. As a result, the tampon may be initially rigid. After insertion and exposure to body fluids, the buffer expands radially. This expansion may not always be uniform outward and may not make complete contact with the surrounding vaginal walls. The patent of E.U.A. No. 2,306,406 appears to describe a tampon that is formed from a flat preform in which the ends meet to form a flower-like configuration. Glutenin glycerin or some other sizing material is impregnated on the cover and allows the buffer to maintain its flower-like configuration. After exposure to fluid, the material softens in the corners similar to petals, which open to expose an interior in a cupped manner. The procedure for making this tampon involves multiple steps and components that can affect the absorption and comfort properties of the tampons. The patent 4,335,720 appears to describe a catamenial tampon having a hollow core opening on its insertion end and having radial grooves at said end in communication with the hollow core.

Finally, the patent of E.U.A. No. 4,294,253 discloses a tampon made of a flat layer of absorbent material bent into a cylindrical shape. A cord is wrapped around the flat absorbent body. The absorbent body is then folded and the edges are welded. The absorbent body is compressed until the final shape of a tampon is achieved. Although this evolved the technique, it nonetheless provides an additional space for improvement, including comfort. Therefore, what is required is a tampon that is simple to perform and that also provides the user with spill protection.

OBJECTIVES OF THE INVENTION An object of the present invention is to provide a novel process for manufacturing absorbent tampons that is versatile and useful for producing a variety of buffer structures. Another object of the present invention is to provide a tampon having at least one structural element comprising at least one element that binds itself in a moisture resistant manner that is capable of maintaining the desired shape of the tampon after that it is compacted and pressed. Yet another objective of the present invention is to provide a tampon that provides an improved fit within the vaginal cavity, thereby providing greater and better containment of body exudates.

An object of a particular embodiment of this invention is to provide a tampon containing a different amount of material in its upper portion, intermediate regions and lower portion, wherein the lower portion has a greater flexibility to allow easy digital insertion of the tampon without the need for an applicator and the upper portion or the intermediate regions have a large amount of absorbent material to allow their absorption capacity. An objective of a particular embodiment of the present invention is to provide a pre-expanded tampon that can be easily inserted into the vaginal cavity of the wearer and that does not substantially change its shape, even after absorption of body fluids. Still another object of the present invention is to provide absorbent bodies useful for creating the tampons described above.

BRIEF DESCRIPTION OF THE INVENTION The objects of the invention are achieved through a tampon having a shirred matrix having a vertex and joined edges. The shirred matrix has a structural element comprising at least one element that attaches to itself in a moisture resistant manner around a central longitudinal portion to form a reinforced core element. The shirred matrix also includes an absorbent body disposed around the core element.

The objects of the invention are also achieved through a process for manufacturing a hygienic tampon wherein the method comprises the following steps: (i) placing a first structural layer comprising material that can be joined, preferably thermoplastic, in front relation with a first surface of an absorbent body to form a substantially planar matrix; (ii) placing the die on a mold having a hole therein; (ni) applying sufficient heat to the first structural layer to bond itself in a moisture resistant manner to form a reinforced core element; (iv) applying force to a central portion of the matrix to drive the matrix through the mold and form a shirred matrix having a vertex and joined edges; (v) cooling the shirred matrix to form an elongated absorbent structure.

BRIEF DESCRIPTION OF THE DRAWINGS The present invention will be described in more detail based on the example of a mode represented in the drawings. The figures show: Figure 1 is a lateral horizontal projection of an absorbent matrix useful for forming a tampon according to the present invention; Figure 2 is a top horizontal projection of the modality of the matrix of Figure 1; Figure 3 is a side horizontal projection of an alternative absorbent matrix useful for forming a tampon according to the present invention; Figure 4 is a lower horizontal projection of the alternative embodiment of Figure 3; Figure 5 is a side horizontal projection of a tampon formed from the absorbent matrix of Figure 3; Figure 6 is a perspective view of the tampon of Figure 5; Figure 7 is a top horizontal projection of the tampon of Figure 5; Figure 8 is a cross section along the line 8-8 of Figure 5; Figure 9 is a horizontal projection of an alternative tampon according to the present invention before absorbing fluids; Figure 10 is a perspective view of the tampon of Figure 9, after absorbing fluids; Figure 11 is a top horizontal projection of an alternative absorbent matrix useful for forming a tampon according to the present invention; Figure 12 is a side horizontal projection of an alternative absorbent matrix useful for forming a tampon according to the present invention; Figure 13 is a top horizontal projection of the alternative embodiment of Figure 12; Fig. 14 is a perspective view of a tampon formed from the absorbent matrix of Fig. 13; Figure 15 is a side horizontal projection of the tampon of Figure 14; Figure 16 is a cross section along line 16-16 of Figure 15; Figure 17 is a schematic view of a process useful for manufacturing the tampon of the present invention; and Figure 17A is a schematic view of the initial part of an alternative procedure to that of Figure 17.

DETAILED DESCRIPTION OF THE INVENTION In accordance with the present invention, a sanitary tampon is formed from an absorbent matrix 10 as shown in Figures 1 and 2. The matrix 10 comprises a substantially flat absorbent structure 12 and has an inner surface 10a, an outer surface 10c and a substantially centered region 10b. A first structural layer 14 is preferably disposed adjacent the absorbent structure 12 on the internal surface 10a of the matrix 10. The matrix 10 may also have axially arranged embossments 15, which guide the bend of the matrix 10 as it is attached and puckering as described below. The shirred matrix can form a tampon while the first structural layer is transformed into an internal reinforced core element by the application of energy, such as heat, and pressure. The reinforced core element may have the shape of a "spine" or skeleton within the tampon. In one embodiment, illustrated in Figures 3 and 4, the absorbent matrix 10 also includes an additional structural layer or cover layer 16 disposed adjacent the absorbent structure 12 on the outer surface 10c of the absorbent matrix 10. In this manner, it is it is evident that the first structural layer 14 and the cover layer 16 of this embodiment are wrapped around the absorbent structure 12 and that they enclose it substantially. This embodiment may also include a containment element 18. The containment element 18 is substantially impermeable to liquids, is substantially smaller than the absorbent structure 12, and is preferably fixed to the absorbent structure 12 through a layer of adhesive 20. The containment element 18 can help prevent spillage of body exudates out of a tampon made of the absorbent matrix 10, even when the tampon is saturated. Additionally, the containment element 18 helps to keep the lower portion or withdrawal end of the tampon somewhat limited, since it is not very expandable. In addition, a strand 22 can be attached to the absorbent matrix 10 to aid in removal of the resulting tampon from the wearer's body. The absorbent matrix 10 can then be gathered around a vertex 23 formed in its central region 10b by joining the distal edges 25. The gathered structure can form a tampon 24 as shown in Figures 5-8 having an insertion end 26 and a withdrawal end 28. When shirred, the first structural layer 14 forms a reinforced core element 30 (shown in Figure 8) about a central longitudinal axis 32 of the tampon 24. The reinforced core element 30 can define a vacuum 34 in u essentially occluding the central longitudinal axis 32. In a preferred embodiment, the reinforced core element 30 defines a vacuum 34 having an average diameter of less than about 1 mm, preferably a non-discernible vacuum. As shown in Figure 5, the withdrawal cord 22 is pressed on the withdrawal end 28. This cord 22 may be extended, as desired, by the wearer. Because the tampon 24 as shown is formed from an elongated structure which is shirred, two opposite side regions 36 are shown, separated by a dividing line 38, which may not be readily apparent in the actual product. These side regions 36 may have a greater concentration of absorbent material.

The buffer 24 as shown in FIGS. 5-8 can also be further compressed, for example, according to the methods described in Friese et al., U.S. Pat. No. 6,310,269B1, and Leutwyler et al., U.S. Patent. No. 5,911, 712 to produce the tampon discussed below with respect to Figures 9 and 10. Buffers according to this embodiment can have an average density of at least about 0.3 g / cm 3, preferably at least about 0.38. g / cm3, and preferably at least about 0.4 g / cm3. The above discussion refers to an elongated absorbent matrix which is gathered around a vertex 23 located at the withdrawal end 28. One skilled in the art will recognize that the vertex can also form the insertion end of the tampon, and that the absorbent matrix can have other shapes such as the circular matrix 10 'illustrated in FIG. 11. Other shapes may include, without limit, elliptical, oval, polygonal (e.g., octagonal and hexagonal) forms. Because the withdrawal end 28 of the present embodiment comprises the apex 23 of the shirred matrix, there is more material at the distal joined edges 25. In this manner, the insertion end 26 has a greater density than the withdrawal end. 28, which mainly comprises the material present in the substantially central region 10b of the absorbent matrix 10 and the containment element 18.

This embodiment may incorporate a greater amount of absorbent material from the joined edges 25 at the insertion end 26, and may also further densify this absorbent material if the tip of the insertion end 26 is round. The insertion end 26, therefore, may have a greater and better ability to absorb body exudates. This increased absorption and containment of exudates at the insertion end 26 can make it possible for the tampon 24 to be able to prevent spills caused by saturation of the absorbent material and / or excessive flow of exudates. It should also be emphasized that a higher concentration of material at the insertion end 26 does not make it difficult for the user to insert the tampon 24, because said portion is strongly compressed to maintain a shape suitable for insertion of the tampon 24. On the other hand, because the withdrawal end 28 has a lower density and is less compacted than the insertion end 26, it is more flexible and smooth. In this way, this end provides the user with greater comfort, and may allow a better adjustment capacity to the lower part of the user's vagina. This improved containment within the vagina can be enhanced by the presence of the containment element 18. Another advantage attributed to the flexibility and lower density of the withdrawal end 28 is related to the better handling and hygiene provided therethrough while the tampon 24 is inserted, that is, in view of the flexibility of the withdrawal end 28, when the tampon 24 is held while being inserted, the wearer's finger deforms the trailing edge of the tampon 24 so that her finger is substantially surrounded by the impermeable material of the containment element 18 as shown in Figure 9. When the tampon 24 is inserted into the vaginal cavity and makes contact with the moisture of the absorbed exudates, it can expand radially, but the expansion is not uniform throughout of the buffer extension. As illustrated in Figure 10, as the insertion end 26 absorbs the body exudates, it expands to better fill the vagina of the wearer. This helps to reduce the passage of said exudates along the vaginal walls. Inasmuch as the withdrawal end 28 has less absorbent material and incorporates the containment element 18, its radial expansion is significantly less than that of the Insertion end 26. This provides buffer 24 with a wedge configuration. This shape can make it easier to remove the tampon 24 after use. The use of an elongated absorbent matrix 10 shown in Figure 3 and the resulting orientation of more absorbent material in the lateral regions 36 allow the tampon 24 to better contain the body exudates. This is because the tampon 24 can expand in a widthwise direction to form a final configuration that is very similar to the configuration of the vaginal cavity. In this case, in addition to the greater amount of material in the first portion, the higher concentration of absorbent material in two intermediate opposite side regions 36, in a two-ear shape, also increases the absorption capacity. This tampon 24 does not expand in a radially homogeneous manner, but instead forms an expanded tampon in width, which can cooperate better with the vaginal cavity. In another embodiment, illustrated in Figures 12 and 13, the absorbent matrix 10 again includes an additional structural layer or cover layer 16 disposed adjacent the absorbent structure 12 on the outer surface 10c of the absorbent matrix 10. Of this Thus, it is evident that the first structural layer 14 and the cover layer 16 of this embodiment are wrapped around the absorbent structure 12 and enclosing it substantially. In addition, a strand 22 can be attached to the absorbent matrix 10 to assist in removal of the resulting tampon from the wearer's body (shown below the first structural layer 14). The absorbent matrix 10 of this embodiment can subsequently be gathered around a vertex 23 formed in its central region 10b by joining the distal edges 25. The gathered structure can form a tampon 24 as shown in Figures 14 and 15 having one end of insert 26 and a withdrawal end 28. As shown in Figure 14, the withdrawal cord 22 extends from the withdrawal end 28. When it is gathered, the first structural layer 14 again forms a reinforced core element 30. In a preferred embodiment, the reinforced core element defines a vacuum 34 around the central longitudinal axis 32 which can accommodate a user's finger to assist in the insertion of the tampon 24. Preferably, the vacuum 34 has a diameter of at least approximately 5 mm. Although this tampon 24 can be further compressed, it is preferred that the tampon 24 be stabilized in an expanded form, for example, the shape in which it leaves the hollow forming tool 108 of FIG. 17. Preferably, the tampon 24 presents a form that does not vary significantly after insertion into the user's vaginal cavity, and even after contact and absorption of body exudates. The buffers according to this embodiment can have an average density of at least about 0.06 g / cm 3. It is also preferred that the stabilized expanded buffer have a density of less than about 0.4 g / cm 3. The tampon 24 of this embodiment can also have two opposite side regions 36 separated by a dividing line 38, which may not be readily apparent in the actual product. Again, these side regions 36 may have a higher concentration of absorbent material. The above discussion refers to an elongated absorbent matrix 10 which is gathered around a vertex 23 located at the insertion end 26. One skilled in the art will recognize that the apex can also form the insertion end of the tampon, and that the matrix Absorbent may have other shapes such as the circular matrix 10 'illustrated in Figure 11. Other shapes may include, without limit, the elliptical, oval, polygonal (e.g., octagonal and hexagonal) forms. Although the tampon 24 shown in Figs. 9-13 has a substantially elliptical cross section, it can also have other cross sections, such as oval, cylindrical, octagonal and others, and although it is shown as generally straight, the tampon 24 may have other shapes alternatives, which include substantially curved along its longitudinal axis, in such a way as to assume the appearance of a vaginal cavity. These modifications can provide a tampon 24 as anatomically correct as possible. The present embodiment of the tampon 24 (Figures 12-16) can provide a pre-expanded product. In contrast to current commercial tampons, the present modality does not allow an important radial expansion and therefore, has the same size and shape before and after its use. That is, the pad 24 has a first initial shape and volume, as soon as it is manufactured, and a final shape and volume, after use, that are substantially identical. Preferably, the volume of the buffer 24 after saturation with fluids or body exudates is less than 120% of the initial volume. The properties of the pre-expanded pad 24 of FIGS. 2-16 can vary through the handling of the components comprising the absorbent body (material and basis weight of absorbent structure 12, material and basis weight of the first and additional structural layers). 14, 16, for example) and the process variables (hollow portion cross section, force and speed applied by the push rod 102, applied energy, application time, and others). The variables can be balanced to provide a buffer that: has a diameter that allows insertion into the vaginal cavity without excessive friction that may cause some discomfort; have a reinforced core element (perhaps with the help of an additional structural element) that binds itself in a moisture resistant manner so that expansion does not occur, even after a long exposure to body fluids, high moisture content and applied forces due to user movement; can have a higher absorption capacity than conventional tampons using the same amount of material (or equivalent capacity with less material) to provide a more economical product; and it can facilitate the removal of the tampon, due to the fact that rolled layers are not formed that can be raised or lowered in spiral, since their shape does not change significantly during use. The vacuum 34 makes it possible to insert the digital tampon of this invention more easily into the vaginal cavity. Vacuum 34 safely and comfortably accommodates a user's finger, gives tampon 24 a stability that makes safe insertion possible, avoids the potential of tampon falling off the finger, avoids contact of the user's finger with the vagina or the external part of the buffer to avoid potential contamination. Again, the above discussion refers to an elongated absorbent matrix 10 which is gathered around a vertex 23 located at the insertion end 26. One skilled in the art will recognize that the apex can also form the withdrawal end of the tampon, and that the absorbing matrix can take other forms as discussed below. Obviously, the use of an applicator (not shown) can be envisaged to assist in the insertion of the tampon 24 into the vaginal cavity. An equipment comprising the applicator can be provided and the tampon can be packaged and sold as a unit. The absorbent structure is preferably formed of absorbent materials including, without limitation, fiber, foam, hydrogels, wood pulp, superabsorbent materials, and the like. The preferred absorbent material for the present invention includes foam and fiber. The absorbent foams may include hydrophilic foams, foams which are easily wetted by aqueous fluids as well as foams in which the cell walls forming the foams absorb fluid. Preferred fibers used in the formation of the absorbent body include regenerated cellulose fiber, natural fibers and synthetic fibers. A useful, and non-limiting list of useful fibers for the absorbent body includes natural fibers such as cotton, wood pulp, jute, and the like; and processed fibers such as regenerated cellulose, cellulose nitrate, cellulose acetate, rayon, polyester, polyvinyl alcohol, polyolefin, polyamine, polyamide, polyacrylonitrile, and the like. Other fibers may be included in addition to the above fibers to add desirable characteristics to the absorbent body. Preferably, the fibers of the absorbent matrix are rayon or cotton, and preferably, the fibers are rayon. The fibers can have any useful cross section. The cross sections of the fiber include multiple segments and without segments. Regenerated multi-segment cellulosic fibers have been commercially available for years. These fibers are known to possess an increased specific absorbency on the fibers without segments. A commercial example of these fibers are the multi-segment viscose rayon fibers Danufil® VY available from Acordis UK Ltd., Spondon, England. These fibers are described in detail in Wilkes et al., U.S. Patent No. 5,458,835, the disclosure of which is incorporated herein by reference. Both the first structural layer 14 and any additional structural layer or cover layer 16 illustrated in Figure 3, are constituted of material that is capable of being bonded to itself in a moisture resistant manner to form a reinforced core element in the tampon. Useful materials include thermoplastic layers (such as films and fibrous tapes or elements such as having thermoplastic powder applied thereto), adhesives, curable materials such as interlacing materials, and the like. In the embodiment illustrated in FIG. 3, the first structural layer 14 is a permeable film or a fibrous tape comprising thermoplastic polymers. A representative, non-limiting list of useful thermoplastic polymers includes polyolefins such as polypropylene and polypropylene, polyesters such as polyethylene terephthalate, nylons, acrylates, and the like. Of course, two or more of these materials may be combined or mixed in a film, a tape of different materials or a tape of two-component fibers (such as polyester fibers coated with polyethylene). In a preferred embodiment, the first structural layer 14 has more thermoplastic fibers than the covering layer 16. Preferably, the first structural layer 14 and the cover layer 16 have a basis weight between about 9 and about 80 g / m2, and preferably, the preferred base weight of the layers is between about 9 and about 15 g / m2. As mentioned above, the use of a tape comprising thermoplastic fiber is not a limiting choice, but a particular modality among others. Preferably, the containment element 18 is formed of a substantially planar layer made of impermeable polymeric material such as a polymeric film, or even another hydrophobic material, such as a hydrophobic nonwoven fabric. The adhesive layer 20 is preferably an adhesive tape or adhesive. Its purpose is to provide greater and better containment of body exudates.

The tampon 24 of the embodiments generally described above can be performed by joining the distal edges 25 of the absorbent matrix 10 and pursing the absorbent matrix 10 around the central region 10b forming the apex 23. This can be achieved by applying force to the the central region 10b, for example using a push bar 102 and at the same time supporting the outer stretched regions of the array, including the distal edges 25 with a shape 104. As shown in FIG. 14, the force is generally applied at an orientation substantially perpendicular to the substantially planar absorbent matrix 10. The transformation of the first structural layer 14 into a reinforced core element 30 is initiated by the application of energy 106, such as heat. The transformation of the first structural layer 14 is assisted by the application of radial pressure. The radial pressure can be applied in a mechanical press in which the press elements move towards the product (radially, longitudinally, axially, or any combination of directions), during transit through a hollow forming tool 108, or any combination of one or more of these press mechanisms. After leaving the hollow forming tool 108, the shape of the absorbent body 24 is maintained due to the transformation of the structural layer 14 into a reinforced core element 30. Preferably, the transformation includes self-bonding of the backing material. the first structural layer 14 in a moisture resistant manner to form the reinforced core element 30. Of course, the reinforced core element 30 can be bonded similarly to the absorbent structure 12. Finally, the additional structural layer or cover layer 16 can also be deformed and bonded to itself and / or to the absorbent structure 12 as the absorbent matrix 10 is gathered to form the tampon. After the buffer 24 leaves the hollow forming tool 108, it can be further processed. For example, it can be compressed in a conventional tampon-forming press, such as Friese et al., U.S. No. 6,310,269B1 and Leutwyler et al., Patent of E.U.A. No. 5,911, 712, the disclosures of which are incorporated herein by reference. The resulting tampon may have an insertion end 26 with a substantially round shape and longitudinal grooves 40 (eg, 40 in Figure 6 or Figures 9 and 10). Additionally or alternatively, the hollow forming tool 108 may be equipped with ridges 110 that form corresponding slots (e.g., 40 in Figure 6) in the tampon 24. These slots help improve the ability of the tampon 24 to maintain a Stable form and can help increase the column strength of the tampon 24. The forming apparatus of Figure 17 has two distinct regions. A first portion includes a shape 104, on which the absorbent matrix 10 for example of FIGS. 9 and 10 is placed. This shape 104 has a truncated conical cavity 104a, which has a first large opening 104b opposite a second opening more. small 104c A second portion of the forming apparatus is a hollow forming tool 108 that follows the second opening 104c. It is preferred that this forming tool 108 determines the final shape of the tampon 24. In a particularly preferred embodiment, the hollow forming tool 108 has a substantially elliptical cross section, but may also have other cross-sectional shapes, such as oval, cylindrical , octagonal, among others. The use of an elongated absorbent matrix 10 shown in Figure 10 and the use of said elliptical forming tool 108 can again provide more absorbent material in the lateral regions 36 that allow the tampon 24 to better contain the body exudates. This is once again due to the fact that the tampon 24 can fill a relatively large space, similar to the shape of the vaginal cavity. Even alternatively, the tube may be substantially curved, such that it provides a tampon that is substantially curved along its longitudinal axis to assume the appearance of the vaginal cavity. Although the push rod 102 may have a substantially cylindrical shape as illustrated in Figure 17, it may be preferable to include an extension 112 shown in Figure 17A. The above procedure uses the application of energy to transform the first structural layer into a reinforced core element. The energy sources may include, without limitation, thermal, ultrasonic, electromagnetic (such as infrared energy and microwave energy), chemical energy (such as a chemical reaction or the removal of a liquid vehicle from a polymeric material), and the like. . A preferred source of energy is thermal energy, such as hot air. This can be applied to the internal surface 10a of the absorbent matrix 10, preferably at a working temperature between 60 ° C and 250 ° C, preferably between 160 ° and 180 ° C. Of course, the temperature may vary depending on the material comprising the first structural element. Preferably, together with a thermoplastic material, the working temperature corresponds to the point where the material begins to soften or even the melting point of the material. The selection of the softening point can be related to the cooling rate of the structure after its formation in a tampon. As already mentioned, the thermoplastic material may comprise a permeable mesh or thermoplastic structure comprising, for example, polypropylene or polyester fibers coated with polyethylene. In the case of coated fibers, the polyester provides structure to the mesh while the polyethylene is melted to connect the fibers in the belt. The second kind of fiber is called double-component fiber, because it contains two different polymers. With the application of the hot air directly on the inner surface 10a of the absorbent matrix 10, all the layers of the matrix are heated, especially the first structural layer 14 which is disposed on the internal surface 10a. The thermoplastic fibers (or other material used, depending on the case) comprising the first structural layer 14 begin to soften and deform due to the application of heat. This results in the transformation of the first structural layer (which adheres to the absorbent structure 12, the cord 22, and other adjacent elements) in the reinforced core element. Preferably, and especially for the embodiment of Figures 12-16, although not necessarily, energy may be applied, such as application of heat to the forming tool 108 in a manner that can modify the additional structural layer to form a structural element external to help maintain the desired shape of the tampon 24. In addition, energy can be applied to the absorbent matrix while it is in the hollow forming tool 108 to further stabilize the shape of the tampon. Although the push rod 102 can move the absorbent matrix through the forming apparatus as heat 106 is applied to the inner surface of the absorbent matrix and / or the internal surface of the forming apparatus, the method can vary so that the Heat application may occur first, when hot air is subsequently applied until a peak temperature is reached, for example between 60 ° C and 250 ° C, and then, as soon as the application of heat ends, the absorbent matrix can be forced through the training apparatus. Buffers are generally categorized into two classes: applicator buffers and digital buffers, and a certain amount of dimensional stability is useful for each type of tampon. The applicator pads use a relatively rigid device to contain and protect the tampon before use. To insert the tampon into a body cavity, the applicator is partially inserted into the body cavity, and the tampon can be expelled therefrom. In contrast, digital tampons do not have an applicator to help guide them into the body cavity and require sufficient column strength to allow insertion without using an applicator. This resistance can be determined by securing one end of the buffer with the fixed plate of an Instron Universal Testing Machine, available from Instron Corporation, Canton, Mass., U.S.A. The movable plate is brought into contact with the opposite end of the tampon and is subsequently adjusted to compress the tampon at a rate of about 5 cm / minute. The force exerted on the tampon is measured continuously, and the point at which this force begins to descend instead of rise is the point at which the tampon is bent. The maximum force achieved is the column strength of the buffer. Preferably, the buffers of the present invention have a significant column strength of at least about 10 N. Most preferably, the buffers have a column strength of at least about 20 N, and preferably have a column strength. from about 30 N to about 85 N. Buffers with a column strength that is too low do not have sufficient dimensional stability to maintain their basic structure during insertion as a digital buffer; tampons with a column strength that is too high can be perceived as too rigid or hard to be inserted comfortably as a digital tampon. Despite the fact that an example of the preferred embodiment has been described, it will be understood that the scope of the present invention encompasses other possible variations, limited by the wording of the appended claims, including possible equivalents.

Claims (35)

NOVELTY OF THE INVENTION CLAIMS

1. - A tampon comprising a shirred matrix having a vertex and joined edges, wherein the shirred matrix comprises: a structural element comprising at least one element that attaches to itself in a moisture resistant manner around a portion longitudinal central to form a reinforced core element; and an absorbent body disposed around the core element.

2. The buffer according to claim 1, further characterized in that the buffer has a column strength of at least about 10 N.

3. The buffer according to claim 1, further characterized in that the reinforced core element defines a vacuum in the central longitudinal portion.

4. The tampon according to claim 3, further characterized in that the vacuum has an average diameter of less than about 1 mm.

5. The tampon according to claim 1, further characterized in that the absorbent body is substantially surrounded by a liquid permeable cover.

6. The tampon according to claim 1, further characterized in that the tampon has an insertion end comprising the joined edges of the shirred matrix and a withdrawal end comprising the apex of the shirred matrix.

7. The buffer according to claim 6, further characterized in that the buffer has an average density of at least about 0.38 g / cm3.

8. The tampon according to claim 6, further characterized in that the tampon further comprises a withdrawal cord extending from the withdrawal end.

9. The buffer according to claim 6, further characterized in that it additionally comprises a containment element associated with the apex of the shirred matrix.

10. The tampon according to claim 6, further characterized in that the insertion end has a greater density than the withdrawal end.

11. The tampon according to claim 10, further characterized in that the withdrawal end is more flexible than the insertion end.

12. The tampon according to claim 1, further characterized in that the tampon has an insertion end comprising the apex of the shirred matrix and withdrawal end comprising the joined edges of the shirred matrix.

13. - The tampon according to claim 12, further characterized in that the buffer has an average density of less than about 0.4 g / cm3.

14. The tampon according to claim 12, further characterized in that the tampon further comprises a withdrawal cord extending outwardly from the withdrawal end.

15. The buffer according to claim 12, further characterized in that the buffer is capable of absorbing liquids and wherein the buffer has an initial volume and volume after fluid saturation, and the volume after fluid saturation is lower. to 120% of the initial volume.

16. The tampon according to claim 12, further characterized in that the absorbent body is substantially surrounded by a fibrous tape cover permeable to liquids, and the first structural element is formed from a fibrous tape.

17. The tampon according to claim 16, further characterized in that the fibrous tape from which the first structural element is formed has a higher basis weight than the fibrous tape cover.

18. A process for manufacturing a sanitary tampon characterized in that it comprises the following steps: (i) placing a first structural layer comprising unicable material in front relation with a first surface of an absorbent body to form a substantially planar matrix; (ii) placing the die in a mold having a hole therein; (iii) apply sufficient energy to the first structural layer to bind itself in a moisture resistant manner to form a reinforced core element; and (iv) applying force to a central portion of the matrix to drive the matrix through the mold to form a shirred matrix having a vertex and joined edges in the form of an elongated absorbent structure.

19. The manufacturing process according to claim 18, further characterized in that the reinforced core element is folded around a central longitudinal portion of the shirred matrix.

20. The manufacturing process according to claim 19, further characterized in that the reinforced core element defines a vacuum in the central longitudinal portion.

21. The manufacturing process according to claim 18, further characterized in that it further comprises the step of forming densified regions of the substantially planar matrix.

22. The manufacturing process according to claim 21, further characterized in that the densified regions radiate outwardly from the central portion of the matrix.

23. The manufacturing process according to claim 18, further characterized in that it comprises additionally incorporating a withdrawal cord with the matrix.

24. - The manufacturing process according to claim 18, further characterized in that it additionally comprises placing a liquid-permeable cover layer in front relation with a second surface of the absorbent body, opposite to the first one.

25. The manufacturing process according to claim 18, further characterized in that the application of heat in step (iii) consists in applying hot air to the first structural layer.

26. The manufacturing process according to claim 18, further characterized in that step (iii) and step (iv) are carried out substantially simultaneously.

27. The manufacturing process according to claim 18, further characterized in that it further comprises compressing the absorbent structure to form a buffer having an average density of at least about 0.06 g / cm 3.

28. The manufacturing process according to claim 27, further characterized in that the buffer has an average density of at least about 0.38 g / cm3.

29. The manufacturing process according to claim 27, further characterized in that it additionally comprises the step of associating a containment element with the second surface of the central portion of the matrix.

30. The manufacturing process according to claim 18, further characterized in that the elongated absorbent structure is the tampon, and the tampon has an insertion end comprising the apex of the shirred matrix. 31.- The manufacturing process according to claim 30, further characterized in that a puncture applies the force to the central portion of the matrix and deforms the first structural layer to form a void in the shirred matrix. 32. The manufacturing process according to claim 30, further characterized in that the energy is also applied to an internal surface of the mold. 33. The manufacturing process according to claim 18, further characterized in that the energy comprises thermal energy. 34.- The manufacturing process according to claim 18, further characterized in that the energy comprises ultrasonic energy. 35.- The manufacturing process according to claim 18, further characterized in that the connectable material comprises a thermoplastic material.