MXPA01001086A - Layered tampon - Google Patents

Abstract

This invention relates to absorbent tampons. More particularly, the invention relates to an improved absorbent tampon having an improved fluid acquisition rate without decrease in capacity or fluid retention characteristics. This is accomplished by an absorbent tampon comprising a layered structure constructed from layers of rayon and cotton. The tampon pledget of the present invention is in the form of a laminar pad of discrete layers. The pledget comprises at least an uppermost layer, a lowermost layer, and at least one intermediate layer positioned between the uppermost layer and the lowermost layer. The uppermost layer and the lowermost layer are each comprised primarily of rayon. At least one intermediate layer is comprised primarily of cotton. In a particular aspect of the invention, the outer layers (i.e. the uppermost layer and the lowermost layer) are comprised of at least about 60%rayon, more preferably at least about 90%rayon, and even more preferably entirely of rayon. In another aspect of the invention at least one intermediate layer is comprised of at least about 60%cotton, more preferably at least 90%cotton, and even more preferably entirely of cotton.

Description

TA PON IN LAYERS FIELD OF THE INVENTION This invention relates to absorbent tampons. More particularly, the invention relates to an improved absorbent pad having an improved fluid acquisition rate without decrease in capacity or fluid retention characteristics. This is achieved with a buffer comprising layers of different material composition. The materials are selected from their different properties with respect to each other in such a way that the resulting buffer combines the advantages of the properties of the various layers.

BACKGROUND OF THE INVENTION A wide variety of catamenial absorbent pads have been widely known in the art. Very fashionable commercially available buffers are made from a buffer absorbing block which has been compressed into a substantially cylindrical shape. Buffer-absorbing blocks of a variety of types and constructions have been described in the art. Prior to compression, the absorbent block can be rolled, spirally wound, folded, or assembled as a rectangular pad of absorbent material. Buffers made from a generally rectangular absorbent block of absorbent material have been popular and successful in commerce. The tampons have been constructed from a variety of absorbent materials. Preferred materials for tampons have included rayon and cotton.

These materials are particularly useful in the construction of the tampon because of its low cost, good absorbency, and proven effectiveness in these products. The very fashionable commercially available tampons are made of either rayon, cotton, or homogeneous blends of the two. An advantage of rayon is that this A typically exhibits a higher absorbency rate than cotton. He On the other hand, cotton is more likely to retain the fluids previously absorbed when subjected to external pressure. Buffers constructed of homogeneous cotton and rayon blends have tried to combine the advantages of both materials. Additionally, numerous attempts have been made in the art for provide a flat tampon mass with a layered structure. For example, the US Pat. No. 3,610,243 entitled "Crosslinked Paper Buffer" issued October 5, 1971 to Jones, Sr. discloses a tampon formed from a multiplicity of tissue paper layers which have been folded in a layer buffer. multiple The Jones device, however, does not incorporate construction layers of different material in order to combine the benefits of each. U.S. Patent No. 3,051,177 issued to Wilson on August 28, 1962 and U.S. Patent No. 3,079,921 issued to Brecht and To others on March 5, 1963, they disclose a two-layered structure and a three-layered structure, respectively. Wilson's device layers consist of a layer absorbent and a permeable cover to protect the absorbent layers. These layers are folded on themselves several times to form a six layer pad. The Brecht device discloses a three-layer buffer composed of a resilient material sandwiched between two absorbent layers. All three layers are bent upwards to form the tampon. 25 U.S. Patent No. 3,371,666 issued to Lewing on March 5, 1968 and U.S. Patent No. 3,628,534 issued to Donohue on December 21, 1971, each disclose a generally flat tampon formed of a plurality of layers. Both of the Lewing and Donohue devices, however, incorporate layers of cotton on the outer side of the flat mass with layers of superabsorbent material inside. The superabsorbent material is a support film only in the Donohue device and is distributed over a carrier web in the Lewing device. Although many of the previously described devices and other tampons generally available have been successful and have gained acceptance in the market, the search for an improved absorbent tampon has continued. Each one of the devices described above suffer from certain disadvantages that are resolved ^ by the development of the present invention. For example, the Wilson and Brecht devices both require extensive bending of a layered structure prior to compression, if any, of the flat mass of the tampon. Additionally, no device uses layers of rayon and cotton to achieve the benefits of the present invention. The Lewing and Donohue devices do not make the most effective use of a layered structure because the cotton layers are located on the outside of the uncompressed flat mass, and because the presence of the superabsorbent material is needed to achieve To the benefits of these devices. Buffers constructed of homogeneous rayon and cotton blends offer some improvements in fluid retention over those constructed of only rayon, but the presence of cotton in the blend tends to erode the benefit of the rayon fluid acquisition rate. Therefore, there is a need for an improved absorbent pad comprising rayon and cotton layers that optimizes the performance benefits of each of these materials. Specifically, this buffer must show high speed of fluid acquisition simultaneously with a high fluid holding capacity. The tampon should be inexpensive and easy to manufacture and constructed so as to offer performance improvements over known tampons that employ rayon and cotton in their construction.

BRIEF DESCRIPTION OF THE INVENTION • This invention relates to absorbent pads, and more particularly an absorbent pad comprising a layered structure constructed from layers of rayon and cotton. The flat mass of the buffer of the present invention is in the form of a laminar pad. The flat mass comprises at least one top layer, one ^ bottom layer, and at least one intermediate layer placed between the top layer and the bottom layer. The upper layer and the lower layer are each composed mainly of rayon. At least one intermediate layer is composed mainly of cotton. In a particular aspect of the invention, the outer layers (i.e., the upper layer and the lower layer) are composed of at least about 60% rayon, more preferably at least about 90% rayon, and even more preferably all of rayon. In another aspect of the invention, at least the intermediate layer is composed of at least 60% cotton, more preferably at least 90% cotton, and still from most preferable way of cotton. The flat mass of the buffer of the present invention can also incorporate a thin envelope surrounding the discrete layers. This wrapping can preferably be composed of rayon. In one aspect of the invention, the total number of layers is three (i.e., the top layer, the bottom layer, and an intermediate layer).

Four total layers can also be used. The flat mass of the tampon can be constructed of discrete layers. Alternatively, the upper and lower layers may be an integral layer that is wrapped around the intermediate layer or layers. A flat tampon mass according to the present invention can also be constructed as a laminar pad comprising an odd number of • alternating layers of a first type and a second type. The layers of the first type comprise the outer layers (i.e., an upper layer and a lower layer) as well as alternating intermediate layers. The layer or layers of the second type comprise alternating intermediate layers. The layers of the first type comprise mainly rayon. The layers of the second type comprise mainly cotton. In one embodiment, the flat mass 10 of the tampon can have a total of five alternating layers. • BRIEF DESCRIPTION OF THE DRAWINGS Although the description concludes with the claims pointing out In a particular manner and claiming differently the exposed matter that is considered as forming the present invention, it is believed that the invention will be better understood from the following description taken in combination with the accompanying drawings, in which: Figure 1 is an exploded view in perspective of a flat mass of the tampon of the present invention. Figure 2 is a perspective view of a flat tampon mass of the invention present in its assembled configuration prior to compression to form a catamenial tampon. Figure 3 is a perspective view of a flat tampon mass of the present invention, which is similar to Figure 2, but showing the addition of an optional envelope.

Figure 4 is a catamenial buffer formed by compression of a flat mass of buffer of the present invention. Figure 5 is an alternate embodiment of a flat tampon mass of the present invention showing a five layer structure. Figure 6 is another alternative embodiment of a flat tampon mass of the present invention showing a four layer structure. Figure 7 is another alternate embodiment of a flat tampon mass of the present invention showing an upper and lower integral layer wrapped around the intermediate layer. Figure 8 is a form of a flat tampon mass of the present invention having an inverted V-shape.

DETAILED DESCRIPTION OF THE INVENTION The present invention is directed to a tampon absorbent planar mass comprising layers of rayon and cotton. The flat mass of the tampon can be compressed to form an absorbent tampon, such as a tampon for menstrual use. Figures 1 and 2 show an embodiment of a flat mass of absorbent buffer, flat mass of buffer 20. However, the present invention is not limited to a structure having the particular configuration shown in the drawings. As used herein, the term "tampon" refers to any type of absorbent structure that is inserted into the vaginal canal or other body cavities for the absorption of fluid therefrom. Typically, the tampons are constructed from an absorbent material which has been compressed in either the radial direction, the axial direction, or both in order to provide a tampon that is of a size and stability that allows for insertion into the vagina or other body cavity. As used herein, the terms "flat mass" or "flat tampon mass" are intended to be interchangeable and refer to a construction of an absorbent material prior to compression of this construction in a tampon as described • 5 previously. Flat tampon doughs are sometimes referred to as a "buffer jig" or a flexible roll, and the term "flat dough" is intended to include these terms as well. In a preferred embodiment of the present invention, the planar mass of buffer 20 is constructed in the manner shown in Figure 1. The flat mass of buffer 20 shown in Figure 1 is a flat, generally rectangular, laminar pad.

Although the flat mass shown in Figure 1 is generally rectangular, other shapes such as trapezoidal, triangular, hemispherical, and inverted-V are also acceptable. The pad is composed of an upper layer 32 and a lower layer 34. Collectively, the upper layer 32 and the lower layer 34 are referred to as the layers. external 40. In addition to the outer layers 40, the flat mass of buffer 20 comprises at least one intermediate layer 38 placed between the upper layer 32 and the lower layer 34. In the embodiment shown in Figure 1, each of the layers that • comprises the flat mass of buffer 20 is a discrete layer. The term "discrete layer" means a layer that is independent of the other layers comprising the flat mass of the tampon 20. Although a single layer bent on itself can be considered as two layers, this configuration is not two discrete layers as the term is used herein. The term "integral layers" means a layer that is constructed as a continuous weft or patch and that is folded on itself either directly or with additional layers between the folds. The laminar pads of both constructions, that is, the pads constructed entirely of discrete layers and pads constructed of bent integral layers, are within the scope of the present invention. The tampon 20 flat mass of the present invention comprises at least the outer layers 40 and one or more intermediate layers 38. Each of the layers may be independent of the others, but need not be so. Although the layers • 5 can finally be bent before the compression of the flat mass 20, that bending is not necessary in all the embodiments of the present invention. The outer layers 40, that is, the upper layer 32 and the lower layer 34, are each constructed primarily of rayon. Each of the outer layers 40 need not have an identical composition of material, but each must be composed mainly of rayon. Preferably, each of the outer layers 40 It is composed of at least about 60% rayon, more preferably at least about 90% rayon. In a particularly preferred embodiment, the upper layer 32 and the lower layer 34 are each constructed entirely of rayon. The construction of the outer layers 40 entirely of rayon, offers the benefits of ease of manufacture while retaining the benefits of synergy of the inner layer. At least one intermediate layer 38 is constructed mainly of cotton. Preferably said inner layer is at least about 60% • of cotton, more preferably at least about 90% cotton. In In a particularly preferred embodiment, at least one intermediate layer 38 is entirely composed of cotton. The rayon used in the tampon 20 flat mass of the present invention can be any suitable type typically used in the disposable absorbent articles intended for in vivo use. These acceptable types of rayon include GALAXY rayon (a three-lobed rayon structure) available as 6140 Rayon from Courtaulds Fibers Ltd., of Hollywall, England. SARILLE L rayon (a rounded fiber rayon), also available from Courtaulds Fibers Ltd., is also suitable. Any suitable cotton material can be used in the flat 20 buffer mass of the present invention. Suitable cotton material includes long-fiber cotton, short-fiber cotton, cotton waste, T-fiber cotton, card strips, and • carder cotton. Preferably, the cotton layers should be a cotton bleached absorbent and cleaned with a glycerin finish. It has been found during the development of the present invention that cotton and rayon each possess certain characteristics and performance properties. It has further been found that when rayon and cotton 10 are combined in the described layered arrangement, the resulting flat mass of buffer shows • superior performance characteristics not achieved in the previous flat pad weights. Rayon is a preferred material for use in tampons because of its high rate of fluid absorption. Additionally, the rayon is highly compressible 15 and has a high fluid capacity on a gram basis per gram. A disadvantage with rayon, however, is that it tends to release the absorbed fluid before it is subjected to an external confining pressure. This phenomenon, sometimes referred to as compression failure or "squeezing", discussed further in U.S. Patent No. 3,749,094. The forces exerted on the tampon by the movements of the body or the contraction of the user's muscle can lead to compression failure. Cotton typically has a lower fluid acquisition rate than rayon and a lower absorbent capacity than rayon on a gram basis per gram. However, cotton is a preferred material for use in tampons because of its superior ability to retain fluid purchased when subjected to pressures. external confinement.

The rate of absorption and the total capacity of the rayon decreases significantly when subjected to external confining pressures approaching those expected to be seen by a tampon during use. Similarly, cotton shows a reduction in capacity when subjected to these forces, but the effect is less pronounced than is the case with rayon. Buffers constructed of homogeneous 50% rayon and 50% cotton blends offer some improvement in fluid retention over those constructed of rayon only, but the presence of cotton in the blend tends to erode the benefit of the acquisition rate of rayon fluid. Significant improvements in buffer absorption rate, 10 and additional reductions in the squeeze have been achieved by the layered structure of the present invention, as compared to homogeneous mixtures of rayon and cotton. The external rayon layers 40 act as a highly compressible, soft material, which rapidly absorbs the fluid. This fluid is then transferred to the intermediate layer 38 composed of cotton which is advantageous for the storage of time prolonged, particularly in the presence of pressure. The flat, layered mass of the tampon 20 is completed as shown in Figure 2 with the above-described layers deposited on top of each other. Optionally, the layers may be wrapped with a relatively sheath 46 • thin, as shown in Figure 3. The wrap or cover 46 can be made from any suitable material and serves to help prevent the fibers of the surface of the flat mass 20 from coming loose in the user's body. A preferred material for wrap 46 is rayon, although other materials including two-component fibers, or other natural or synthetic fibers may also be suitable. The wrap 46 does not typically contribute significantly to the overall absorbency of the dough of the buffer 20 and is therefore not considered one of the layers of the present invention. As shown in Figure 3, the wrap 46 can wrap around the major surfaces and can also wrap the ends of the flat mass 20 while leaving the sides uncovered. In an optional variation, the wrap 46 can completely surround all surfaces of the flat mass 20 including the sides. In another optional variation, wrap 46 can surround the sides and main surfaces • 5 of the flat mass of the tampon 20, but not covering the ends. Each of the absorbent layers of the tampon 20 flat mass can have a basis weight of about 50 g / m2 to about 250 g / m2. The wrapping layer 46 can have a basis weight of about 10 g / m2 to about 50 g / m2. A withdrawal cord 48, an example of which is shown in Figure 2, is typically fixed to the flat mass 20 for removal of the tampon after use. The withdrawal cord 48 may be fixed in any suitable manner known in the art including sewing, adhesive fixation, or a combination of the known joining methods. To form a ready-to-use buffer, the flat mass of buffer 20 is compressed and heat conditioned in any suitable conventional manner. Pressures and temperatures suitable for this purpose are well known in the art. Typically, the flat mass 20 is compressed in both the radial direction and in the axial direction using any of the means known in the art.

• Although a variety of techniques are known and acceptable for this purpose, a tampon compression machine available from Hauni Machines, Richmond, VA. It is adequate. Figure 4 shows a complete buffer 50 according to the present invention after it has been compressed. As shown in Figure 4, the volume of the exposed surface of a tampon 50 constructed from a flat mass of buffer 20 of the present invention tends to comprise the thin envelope 46. (when a wrap is used). In the absence of an envelope 46, the outer layers 46 themselves will comprise the volume of the surface area of the compressed tampon 50. Consequently, the benefits of layering the tampon 20 flat mass of the present invention are effected even after the compression of the flat mass 20 in a finished tampon 50. The advantages of the tampon 20 flat mass of the present invention include its low cost, its ease of construction, and use of easily available and tested materials. The flat mass of buffer 20 need not have, and preferably does not have, any superabsorbent material incorporated therein. Each of the layers of the flat mass 20 can be of approximately the same thickness and provide all the total absorbency needed for the finished buffer. Other variations in the embodiment of the present invention shown in # * ^ Figures 1 and 2 are also possible. For example, a five-layer structure, as shown in Figure 5, can also be used. In such an embodiment the outer layers 40 (ie, the upper layer 32 and the lower layer 34) are comprised primarily of rayon. The layers placed between the upper layer 32 and the lower layer 34 are collectively referred to as the inner layers 36. At least one of these inner layers 36 are composed primarily of cotton. In the embodiment shown in Figure 5, the flat tampon mass 20 has alternating layers of rayon and cotton. There are, therefore, two layers of cotton 58 located adjacent each • one to the outer layers 40. The middle layer 42 can be a layer of cotton, a layer of rayon, or a mixed layer. In the embodiment shown in Figure 5, the core layer 42 is an additional rayon layer to preserve the alternating layer relationship and to better distribute the fluid as the tampon becomes saturated. Another embodiment of the tampon 20 flat mass of the present invention is shown in Figure 6. This embodiment is a four layer structure. The layer Upper 32 and lower layer 34 are mainly composed of rayon according to the present invention. At least one of the inner layers 36 is composed mainly of cotton. In the embodiment shown in Figure 6 both inner layers 36 are composed of cotton. Yet another embodiment of the tampon 20 flat mass of the present invention is shown in Figure 7. This embodiment uses an integral layer 60 composed mainly of rayon, according to the present invention, as both of the upper layer 32 and the lower layer 34. The integral layer 60 is wrapped around the intermediate layer 38. Another intermediate layer 38 can be used, or can be used a plurality of these layers. At least one of the intermediate layers 38 is constructed mainly of cotton. The intermediate layer 38 or layers may be discrete or integrals. A benefit of using said integral layer 60 as shown in Figure 7 is that the portion of the flat mass of tampon 20 that will become the head of the compressed tampon may also be composed primarily of rayon. This allows the advantages described above for the layered structure to extend towards the tampon head as well as to the tampon body. 15 A variation of the modality shown in Figure 7 could include an initial two-layer structure. For example, a major composite top layer of rayon could overlap a lower layer composed mainly of cotton. The two layers can then be folded as a unit in such a way that the top layer and • The resulting lower layer are composed mainly of rayon. The layer mainly of cotton is such a structure that later it would be the intermediate layer and would be folded on itself once. Figure 8 shows a variation of the shape of the flat mass of buffer 20 of the present invention. In the embodiment shown in Figure 8, the flat tampon mass 20 has an inverted V-shaped plan view prior to compression. Other variations of the tampon 20 flat mass of the present invention are also possible. Any number of total layers can be used. The layers do not need to overlap completely and can be oriented in different directions. The arrangement and composition of the layers can be varied by providing external layers which are composed mainly of rayon and at least one intermediate layer which is composed mainly of cotton. Although the particular embodiments of the present invention have been illustrated and described, it would be obvious to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention.

Claims (10)

1. A flat mass of buffer in the form of a laminar pad, ^ comprising the flat mass of buffer: a top layer, a bottom layer, and therefore 5 less an intermediate layer placed between the upper layer and the lower layer, characterized in that each of the upper layer and the lower layer is mainly composed of rayon, and wherein said at least one intermediate layer is composed mainly of cotton.

2. The flat tampon mass according to claim 1, Wherein each of the top layer and the bottom layer is composed of at least 60%, preferably at least 90%, most preferably all of rayon, and said at least one intermediate layer is composed of at least 60%, preferably at least 90%, more preferably entirely from cotton.

3. The flat tampon mass according to claim 1, further comprising a thin envelope surrounding the layers.

4. The tampon flat mass according to claim 3, wherein the thin envelope comprises two component fibers.

5. The flat tampon mass according to claim 1, wherein the total number of layers is three or four.

6. The flat tampon mass according to claim 1, wherein each of the upper layer and the lower layer is a discrete layer.

7. The flat tampon mass according to claim 1, wherein the upper layer and the lower layer are constructed from an integral layer that is wrapped around at least one intermediate layer.

8. The flat tampon mass according to claim 1, wherein the flat mass is generally rectangular in shape.

9. The flat tampon mass according to claim 1, wherein the flat mass is inverted V-shaped.

10. A flat tampon mass characterized in that the flat mass comprises a laminar pad of an odd number, preferably five, of alternating layers of a first type and a second type, wherein the layers of the first type comprise at least one top layer and a lower layer, said layers of the first type being composed mainly of rayon, said flat tampon mass further comprising at least one layer of said second type, at least one layer of second type being composed mainly of cotton.