MXPA98004879A - Tampon with improved characteristics of rapida expans - Google Patents

Abstract

The present invention relates to a tampon formed of a substantially cylindrical mass of compressed fibers substantially enclosed in a fluid-permeable cover having improved ability to prevent rapid draining, this buffer has a stability of at least 15 N, and is capable of expanding radially when exposed to a humid environment, the radius increases by at least about 10% after 15 minutes to 50% relative humidity at 40

Description

TAMPON WITH IMPROVED FEATURES OF RAPID EXPANSION CAMPQ PE A TN EN q This invention relates to a radially expandable, generally cylindrical, compressed fibrous tampon. These buffers expand radially in high humidity environments and provide improved characteristics of rapid expansion, BACKGROUND OF THE INVENTION Catamenial tampons are used to absorb »not block the flow of menstrual fluids to prevent draining» for example »staining the user's garments. Unfortunately, commercial tampons are subject to two main types of failure: a buffer instability to continue absorbing fluids once the absorption capacity of the buffer is reached and an instability of the tampon to expand immediately to fill the vaginal cavity. Then »until the tampon expands suffciently to substantially fill the vaginal cavity» the menstrual fluid can flow along the side of the tampon and surpass its absorbent portions as the central part.

Generally »tampons are made of absorbent fibers» such as rayon »cotton or a mixture of these two fibers. The volume of the absorbent fibers necessary to provide sufficient absorption capacity must be highly compressed to form a cylindrical tampon of a sufficiently small size to allow its convenient insertion into the body. The compression must be adequate to keep the tampon in cylindrical form until its insertion. As a result the buffer. when it is first inserted into the body, it is generally very compressed in a relatively uncomfortable way with a relatively high initial density. Then »the tampon initially can not conform immediately to the vaginal walls after its insertion. The high density can also initially inhibit the rapid expansion of the buffer. The expansion "if it occurs at all" occurs only when the tampon makes contact with a sufficient amount of menstrual fluids to inflate the absorbent fibers and to release the expansion force enclosed within the tampon when it is compressed. Therefore »the tampon is liable to pass drains as described above There have been several attempts to solve the problem of early runoff by providing rapid expansion buffers, however, these designs have two disadvantages: first, several designs they are based on synthetic materials that are not currently widely accepted for use in internal medical devices, and secondly, many designs have an insuf fi cient stability and therefore require the use of an applicator, they can not be used as digital tampons. based on synthetic materials include those using foams such as Schaefer »US Patent No. 3» B15 »S01; Dulle» US Patent No. 3 »794» 029 »and Fries and others» US Patent No. 4,341,214 »Or resin fibers such as Wolfe and others» US Patent No. 4> 543 »? 9B; and Tellert» US Patent 4,475,911 Designs that require applicators include ies and others and Sellert, in addition »Wal on and others» patent of E.U.A. Do not. 4. 627-849 describe the use of pre-cut cotton made from natural fibers to obtain a compressed tampon of rapid expansion. However, this design requires several additional manufacturing steps to form pre-cut cotton. There is a desire to evade the premature expansion of these compressed tampons, especially those in which more lens fibers are used. For example »Courtaulds PLC EP 0 301 874 Bl» describes a buffer with regenerated mutelylobulated cellulose fibers whose patent claims provide high absorbency and a handle of cotton-like material. It is described that these buffers have good stability and absorbency. Buffers that expand longitudinally having these fibers are described as having less expansion than conventional tampons that expand longitudinally. Therefore, what is needed is a radially expandable tampon having substantial dimensional stability before use while expanding rapidly in high humidity environments.

BRIEF DESCRIPTION OF THE INVENTION A tampon has been developed that can be expanded in the presence of high humidity after its insertion in the user's body to prevent the early draining step from occurring. This tampon is a substantially cylindrical mass of compressed fibers contained within a fluid-permeable cover. The buffer has a stability of at least about 15 N "and is capable of radial expansion when exposed to a humid environment. The radius increases by at least 10% after 15 minutes at 90% relative humidity at 40 ° C.

BRIEF DESCRIPTION OF THE DRAWING Figure 1 is a cross-section of a mode of a tampon in accordance with this invention.

DETAILED DESCRIPTION OF THE INVENTION Absorbent buffers are generally cylindrical masses of compressed fiber masses having a substantially central axis and a radius that defines the outer circumferential surface of the tampon. Buffers are generally first formed by obtaining a mass of non-woven fibers referred to as a buffer pattern. This pattern can be rolled fibrous cotton »a segment of a fibrous tow» a mass of disorderly oriented fibers »a pattern of substantially uniform oriented fibers» and the like. Therefore, the fibers can have various orientations. The coiled patterns can be formed of a carded network which is then wrapped around an axis perpendicular or parallel to the major axis of the network. If the network is wound around a perpendicular axis, most fibers are oriented in a circumferential manner or generally tangent to the radius of the buffer. If the network is entangled around a parallel axis, most of the fibers are oriented generally parallel to the central axis of the tampon. If the pattern is formed of a fibrous tow, the majority of the fibers will generally be oriented parallel to the central axis of the tampon. The tampon pattern is relatively uncompressed and has a relatively low fibrous density. It is generally compressed to form a finished product having overall dimensions smaller than those of the pattern. When the pressure is released, after moderate mechanical compression »a buffer tends to expand towards its original dimensions. Therefore »buffer patterns are generally overcoded to allow them to return slightly to the density desired for their use. The mechanical overpressure constrains the expansion to prevent the tampon from expanding without the addition of liquid. 5 Overcompression of the mass of fibers forming the buffer provides a certain degree of dimensional stability, especially the longitudinal breaking strength. This measurement is usually described as the stability of the í buffer. Preferably, the buffers of this invention have a significant stability »of at least about 15N. More preferably, the buffers have a stability of at least about 20N, and more preferably, they have a stability of near SON to about 85N. Buffers with a stability that is very low do not have 1-5 sufficient dimensional stability to maintain its basic structure during insertion as a digital buffer; tampons with a stability that is very high can be perceived as very stiff or hard to be inserted comfortably as a digital tampon. The tampons are generally categorized into two classes: applicator caps or digital tampons. The applicator buffers 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 from there. Since the tampon is protected by a rigid applicator device »the tampon does not need to have a high degree of dimensional stability. In contrast »digital tampons do not have an applicator to be able to guide them inside the body cavity and require sufficient stability to allow insertion without the use of an applicator. The compressed tampons may have a generally uniform fibrous density through the buffer. or they may have regions of different density as described in the applications commonly assigned to Friese and others »E.U.A. Serial No. 07 / 596,454 and Leutwyler et al. E.U.A. Serial No. 0B / 196.GG4 whose descriptions are included here for reference. Preferably, the buffer 10 has a relatively dense core 12 substantially surrounding the central axis 14 and a less dense ring 16 surrounding the central axis 14 and a less dense ring 16 surrounding the core 12 and forming the outer circumferential surface 18. This is illustrated in Figure 1. This differential density can be provided by distribution of relatively uniform fibers within the core 12 and the ring 16"or can be provided by several ribs 20 extending radially (in the direction R) from the core 12. In a preferred modality, each rib 20 is separated from the adjacent ribs where it joins the core 12, ie »to its root 22» and each rib 20 contacts adjacent ribs »v. gr. »to 24, close to the circumferential surface IB of the tampon. In addition, the tampon has a cover 26.

The tampon fibers are compressible, that is, they can be compressed to hold a generally compressed form, but they can also expand to a relatively uncompressed state when exposed to sufficient moisture. This humidity can be liquid or vapor. Preferably, the fibers include hydrophilic fibers, and more preferably, the fibers include absorbent fibers, ie the individual fibers absorb fluids. A non-limiting list of useful and non-useful fibers for tampons includes natural fibers such as cotton »wood pulp» jute and similar »and processed fibers such as regenerated cellulose, cellulose nitrate, cellulose acetate» rayon »polyester» polyvinyl alcohol » polyolefin »polyamine» polyamide »pol acrylonitrile and the like. Other fibers in addition to the above may be included to add desirable characteristics to the absorbent body. For example. Hydrophobic fibers can be used on external surfaces of the buffer to reduce surface moisture and hydrophilic fibers can be used to increase the speed of fluid transport within and throughout the body. Preferably »the fibers of the tampon are rayon or cotton» and more preferably »the fibers are rayon. The fibers can have any useful cross section. Preferred fiber cross sections include various branches or no branches. More preferably, the fibers are predominantly multi-branched.

The regenerated cellulose fibers have been commercially available for several years. It is known that these fibers have increased specific absorbance compared to unbranched fibers. A commercial example of these fibers are Talaxy ™ viscose rayon fibers available from Courtaulds PLC, London. England. These fibers are described in detail in Courtaulds PLC. EP O 301 874 Bl. whose description is included here by way of reference. This fibers with several branches are described as consisting of a solid filament of regenerated cellulose material having a decitex of less than 5.0 and a cross-section of a very large diameter. each branch having a length to width ratio of at least 2: 1. The fibers are preferably fibers of short length having three or four branches and a generally symmetric transverse-sectional shape, v. gr. »In the form of Y. X» H or T. A preferred cross-sectional shape is Y-shaped having an angle between the branches of about 120. The preferred regenerated cellulosic material is viscose having a cellulose content of 5 to 12% in weight and a caustic soda content of 4 to 10% by weight. The fibers are preferably wetted having a salt figure of 4.0 to 12.0. It is expected that any commercially available fiber or other fiber such as those "not commercially available today" will be useful in the practice of this invention. It is only required that the fibers are directed to an absorbent body having a high specific absorption capacity which is increased by the addition of a lesser absorption "an unbranched fiber to form a fibrous absorbent body. It has been found that buffers that include from about 25% by weight to 100% by weight of highly hydrated fibers provide the rapidly expanding properties. The fibers may be a mixture of highly branched and unbranched fibers. Preferably, the buffer includes about 25% by weight to about 100% by weight of the hard fibers and about 75% by weight to about 0% by weight of the unbranched fibers. More preferably, the buffer includes from about 50% by weight to about 100% by weight of highly-branched fibers and from about 50% to about 0% by weight of unbranched fibers. Sufficient fibers are included in the fibrous network that forms the buffer to provide a radial increase of at least almost 10% after 1S5 minutes of exposure to 90% relative humidity at 40ßC (90% RH at 40 ° C.) Preferably the buffer has a radial increase of at least about 20% after 15 minutes (90% RH at 40 ° 0 »and still more preferably» the buffer has a radial increase of about 20% to about 25% after 15 minutes ( 90% RH at 40 ° C.) The buffer preferably has a radial increase of at least about 155 after 30 minutes (90% RH at 40 ° C) and more preferably, the buffer has a radial increase of about 25% to about 40% after 30 minutes (90% RH at 40 ° C). The buffer preferably has a radial increase of at least almost 15% after 45 minutes (90% RH at 40 ° C). The unbranched fibers and the muitrapers are preferably combined with a substantially uniform mixture of fibers. These fiber blending operations are known to those skilled in the art. For example »the fibers can be continuously dosed in a sawtooth opener. The combined fibers can be transported »v. gr. »By air through a conduit to a carding station to form a fibrous network. This network can then be processed to form a buffer. In a process for forming a tampon »the network can be formed into a fibrous wick and spirally wound to form a tampon pattern. In addition, a liquid permeable cover material can be wrapped around the buffer pattern to substantially contain the absorbent fibrous portion of the buffer. During use. The buffers of this invention absorb moisture and liquids and expand radially. As used in the specification and in the claims, the term "radially expanding" and the variations of this term refer to the expansion of generally cylindrical buffers. These buffers are expanded primarily in a direction perpendicular to the central axis of the tampon. Preferably, the buffers expand in at least one direction perpendicular to the central axis, more preferably in at least two directions. More preferably, the buffers expand substantially uniformly in all directions perpendicular to the central axis. The buffer pattern is substantially enclosed by a fluid-permeable cover. Therefore »the cover encloses a greater part of the external surface of the tampon. This can be achieved as described in Friese »patent of E.U.A. No. 4,816,100 »which is mentioned here as a reference. In addition »one or both ends of the tampon may be enclosed in the cover. Of course »to process or other reasons» some portions of the surface of the tampon can be free of the cover. For example, the insertion end of the tampon and the portion of the cylindrical surface adjacent this end may be exposed without the cover to allow the tampon to accept the fluids more easily. The cover can reduce the insertion of the tampon into the body cavity and can reduce the possibility of the fibers separating from the tampon. Useful covers are known to those skilled in the art. They can be selected from an outer covering of fibers that are glued together (as by thermo-union). a nonwoven fabric »an open film or the like. Preferably the cover has a hydrophobic termination.

EXAMPLES EXAMPLE A series of fibrous webs were formed by adding a measured quantity of regenerated cellulosic short fibers (Galaxi ™ fibers, 3.3 diner »rayon fibers available from Courtaulds Fibres, London, England) and short, unbranched fibers of regenerated cellulose (Danufil ™ fibers, rayon fibers, available from Hoescht Kehlheim, Kehlheim, Germany). The fiber components were weighed using a component scale, mixed into a bullet separator and subsequently opened into a serrated tooth opener. The resulting combination was carded to obtain the fibrous network. These nets were then used to manufacture radially compressible tampons and generally cylindrical tampons in accordance with the procedure of the commonly assigned applications to Friese et al., E.U.A. series No. 07 / 596,454. and Leutwyler and others. E.U.A. series No. 08 / 196,664 and covered in accordance with the procedure of Friese, patent of E.U.A. No. 4.B16.100. These buffers were conditioned at 65% RH at 21 ° C for at least 24 hours and the initial diameter was measured. The initial composition and diameter of these buffers are identified below in Table 1. Normal differences in diameter are included in parentheses.

TABLE 1 Product Diameter Size% in weight% 1sn test weight the average sample of Room? And rayon (n) (mm) (%) (%) Comp. Ex. A 5 13.20 (0.17) 0 100 Ex. B 5 13.50 (0.17) 0 0 Ex. C 5 13.46 (0.13) 0 25 Ex. D 5 13.38 (0.12) 0 50 Ex. E 5 13.20 (0.14) 0 75 The tampons (conditioned afterwards were placed in high humidity environment (90% relative humidity at 40 ° C) During this exposure, the diameter of the buffer was measured at intervals of 15 minutes.The results are illustrated in Table 2. new, the normal differences of the measured diameter are included in parentheses.

TABLE 2 Product Diameter a: test 15 min. 30 min. 45 min. 60 min. (mm) (mm) (m) (m) comp. 13.83 14.30 14.52 15.09 Ex. A (0.66) (0.27) (0.37) (0.24) Ex. B 16.83 18.15 19.36 20.06 (0.73) (1.00) (0.85) (O.63) Ex. C 16.06 17.40 18.79 19.91 (0.27) (0.69) (O.39) (0.39) Ex D 15.97 17.42 18.SO 19.76 (O.5) (0.50) (O. 8). { O.30) Ex. E 14.45 14.97 15.19 15.lO ((00..2222)) ((00..4477)) ((00..3344)) ((0O..32) From these data, it can be seen that the incorporation of fibers The rapid expansion of a compressed tampon in a high humidity environment in a compressed buffer that does not include these fibers should be noted, it should be noted that the buffers did not have a significant amount of fluid during this experiment ( approximately Ol g / buffer after 60 min.).

EXAMPLE 2 A series of fibrous webs having Gala? I ™ fibers of 75% by weight and Danufil ™ fibers of 25% by weight were formed as in Example 1 above. The fibrous networks were then formed into tampon and compressed patterns. Three different styles of tampon patterns were formed: folded »rolled and cut. To form the folded pattern »a section of approximately eight times the length of the tampon pattern was folded back and forth in five fold lines, perpendicular to the length of the net. Each fold line was separated by the length of the buffer pattern. Then, the tampon pattern had two cut edges and two fold lines at one longitudinal edge thereof and three fold lines at the opposite longitudinal edge, and a portion of most of the fibers was oriented substantially parallel to the center of the axis. To form the rolled pattern, a fibrous network section was entangled around the central axis. Then, a larger portion of the fibers was oriented substantially circumferentially. To form the cut pattern, the intermediate fold lines of the folded pattern were replaced by cut lines. Then the tampon pattern had six cut edges at each longitudinal end thereof, and a larger portion of the fibers was oriented substantially parallel to the central axis. These buffer patterns were further processed to form buffers and conditioned as described above. The composition and initial diameter of these buffers are identified later in Table 3. Normal diameter differences are included in parentheses.

Product Diameter of Diameter Type of test pattern the average sample of buffer (n) (mm) Ex. F 6 13.24 (0.26) Folded Ex. G 6 13.12 (0.13) Enrol side Ex. H 6 13.25 (O. IO) chopped up Again, the conditioned buffers were placed in a high humidity environment (90% relative humidity at 40 ° C). During this exposure, the diameter of the buffer was measured at 15 minute intervals. The results are illustrated below in Table 4. Again, the normal differences in diameter measurements are included in parentheses.

TABLE 4 Product Diameter a: test 15 min. 30 min. 45 min. 60 min. (mm) (mm) (mm) (mm) Eg F 14.76 15.81 16.27 16.57 (0.88) (0.96) (1.00) (1.04) Eg G 15.32 16.18 16.43 16.84 (0.18) (.044) (0.28) (0.38) Ex. H 15.54 16.31 16.60 16.93 (0.29) (0.75) (0.14) (0.19) From these data, it can be seen that the compressed tampons of this invention show rapid expansion in a high humidity environment if the fibers are oriented circumferentially and longitudinally. The specification and the above examples are presented to assist in the completion and unlimited understanding of the invention described herein. Since many variations and embodiments of the invention can be made without departing from its essence and scope, the invention is indicated in the claims appended hereto.

Claims (21)

NOVELTY OF THE INVENTION CLAIMS

1. - A dimensionally stable tampon (10) consisting of a substantially cylindrical mass of compressed fibers substantially enclosed by a liquid permeable cover (26), the tampon (ÍO) having a central axis (14), a radius and a stability of less about 15 N and being able to expand radially when exposed to a humid environment, further characterized because the radius increases by at least about 10% after 15 minutes of exposure to 90% relative humidity at 40 ° C.

2. The buffer (10) of claim 1 further characterized in that a majority of the fibers are oriented in a substantially perpendicular direction of said radius.

3. The buffer (10) of claim 1 further characterized in that a greater part of said fibers are oriented substantially parallel to said central axis (14).

4. The buffer (10) of claim 1 further characterized in that a greater part of said fibers are oriented in a substantially circumferential direction.

5. The tampon (10) of claim 1 further characterized in that the fibers consist of about 25 to 100% by weight of short fibers having a cross section having at least three branches and around 75 to 9% by weight of unbranched short fibers.

6. The buffer (10) of claim 5 further characterized in that said multi-branched fibers consist of regenerated cellulosic material.

7. The buffer (10) of claim 6 further characterized in that said regenerated cellulosic material consists of viscous rayon.

8. The buffer (IO) of claim 5 further characterized in that said unbranched fibers consist of a regenerated cellulosic material.

9. The buffer (10) of claim 8 further characterized in that said regenerated cellulosic material consists of viscous rayon.

10. The buffer (10) of claim 1 having a diameter further characterized in that said buffer radius increases to at least about 20% after 15 minutes at 90% relative humidity at 40 ° C.

11. The tampon (10) of claim 1 further characterized in that said cover (26) consists of a non-woven fabric.

12. The tampon (10) of claim 1 further characterized in that the tampon (10) consists of a fibrous core (12) substantially surrounding the central axis (14), the core (12) having a first average density »and an outer ring (16) forming a circumferential surface (18) of the buffer (10). the ring (16) having a second average density that is less than the first average density. 13.- The buffer (10) of the re-indication 12 consisting of fibers, resilient, multifilated »of regenerated cellulose. 14. The buffer (10) of claim 13 further characterized in that the multi-branched cellulosic fibers consist of rayon fibers having at least three branches. 15. The tampon (10) of claim 12 further characterized in that the outer ring (16) consists of several ribs (20) extending radially of the core (12) 16. The tampon (10) of claim 14 further characterized in that each rib (20) is separated from the adjacent ribs (20) where it is attached to the core (12) and each rib (20) contacts adjacent ribs (20) next to the circumferential surface (18) of the tampon (10). 17. The tampon (10) of claim 1 consisting of an effective amount of resilient short fibers substantially enclosed within said cover. (26), said fibers having a highly variable cross-section having at least three branches to provide an increase in the diameter of the tampon by at least about 10% after 15 minutes of exposure to about 90% relative humidity at approximately 40 ° C; further characterized in that the buffer (10) has a fibrous core (12) substantially surrounding the central axis (14). the core (12) having a first average density and an outer ring (16) forming a circumferential surface (18) of the buffer (10) »the ring (16) having a second average density that is less than the first average density. 18. A method for forming a compressed "radially expandable" tampon generally cylindrical (10) having improved characteristics of rapid expansion consisting of the steps of: - forming a network having approximately 25 to 100% by weight of short fibers resilient having a cross-section having a cross-section having at least three branches and around 0 to 75% by weight of unbranched short fibers »said network having a length dimension» substantially perpendicular to both a width dimension and a density dimension; - orienting a greater part of said fibers, which are substantially parallel to said longitudinal dimension; - winding a portion of said network about an axis substantially parallel to said width dimension to form a generally cylindrical buffer pattern having a central axis (14). said tampon pattern having a length corresponding substantially to the width dimension of said network; - substantially covering said buffer pattern with a fluid-permeable cover (26); and - compressing said tampon pattern radially towards said central axis (14). 19. The method of claim 18 further characterized in that the step of compressing the pattern consists in forming a fibrous core (12) substantially surrounding the central axis (14), the core (12) having a first average density »and several ribs (20) are spaced apart from the adjacent ribs (20) where they join the core (12) and each rib (20) contacts adjacent ribs (20) proximate the circumferential surface (18) of the pad (10). 20. A method for increasing the rapid expansion of a compressed, radially expandable »generally cylindrical tampon (10) consisting of the steps of: - incorporating an effective amount of residual short fibers to provide an increase in compressed tampon diameter to at least 10% after 15 minutes of exposure to about 90% relative humidity at about 40 ° C in a network having a longitudinal dimension "substantially perpendicular to both a width dimension and a thickness dimension" said short fibers I have lenses with a cross section that has at least three branches, orient a greater part of said fibers to said longitudinal dimension of said network, wind said network about an axis substantially parallel to said longitudinal dimension to form a cylinder. of substantially continuous low density fibers; - substantially enclosing said buffer network with a fluid permeable cover (26). - compressing said fiber cylinder radially inward of said central axis (14) to form a compressed cylinder; and - tightening a length of said compressed cylinder to form a tampon (10). 21. The method of claim 20 further characterized in that the step of compressing the tampon pattern consists in forming a fibrous core (12) substantially surrounding the central axis (14). the core (12) having a first average density, and several ribs (20) to which the core (12) is added and each rib (20) contacts adjacent ribs (2?) close to the circumferential surface (IB) of the tampon (lO >