MXPA95002198A - Non-woven absorbent polymeric fabric that display improved fluid handling and methods to make the m - Google Patents

Abstract

The present invention relates to a porous structure having a density of at least about 0.01 g / cc, and a weight of from between about 0.5 ounce per square yard to about 5 ounces per square yard where the structure porous is adapted to absorb at least 2 milliliters of a bovine oxalate-blood fluid in less than 45 seconds and at about 5 minutes from the moment when the oxalate-bovine blood enters the undisturbed porous structure, more than about 75% of said fluid is retained by the pore structure

Description

POLYMIRAL ABSORBENT OR WOVEN TUBE Qül EXHIBITS HANEJO DI IMPROVED FLUID AND METODOß TO MAKE THE SAME INVENTORS: Ali Yahiaoui, David Charles Potts, Cheryl Anne Perkins, Michael David Powers, Jerald Theodore Jascomb, of North American nationality, with addresses in 2003 Harbor Landing, Rosvell, Georgia 30076; 5268 Wynterhall Court, Dunwoody, Georgia 30338; 17 Brentwood Lane, Appleton, Wisconsin 54915; 813 Vinson Court, Woodstock, Georgia 30188 and 3022 Steeplechase, Alpharetta, Georgia 30201, United States of America.

OWNER Kimberly-Clark Corporation, American national residing at 401 North Lake Street, Neenah, Wisconsin 54956-0349, United States of America.

EXTRACT DB LA XMVENCSOH A porous non-woven absorbent structure formed of fibers is described. The porous structure has a basis weight in the range of at least about 0.25 ounces per square yard to about 10.0 ounces per square yard, a density of at least about 0.01 grams / cubic centimeter to about 0.15 g. / cubic centimeter. The porous structure is adapted so that with the application of at least 2 milliliters of blood coil in oxalate flows to a surface thereof, sub-substantially all the fluid enters the volume of the porous structure within about 45 seconds. The porous structure may be single layer or include multiple layers.The single layer structure is formed of spunbonded thermoplastic fibers which include an internal hydrophilic additive.The multilayer structure is formed by laminating a fabric bonded by The second layer may be formed of natural or synthetic fibers.When formed of synthetic fibers, the second layer is generally formed of meltblown fibers which may also include an internal hydrophobic additive. The layers, either spunbonded or meltblown, can be either monocomponent or bi-component. In some applications a film impermeable to the liquid can be secured to a surface of the second layer.

FIELD DB THE INVENTION The present invention is directed to porous absorbent structures and more particularly to absorbent structures formed in part of fibers. Such absorbent structures are useful in the fields of professional health care and personal care, such as infant care, adolescent care and adult care.

BACKGROUND DB THE INVENTION Non-woven fabrics are used to make a variety of products which desirably have particular properties, such as, for example, softness, strength, uniformity, thickness, and absorbency. Such products include towels, industrial cleansers, incontinence products, infant and adolescent care products such as diapers, absorbent feminine care products, garments, such as medical clothing, and fabrics for professional health care such as as surgical drapes. Many of these products spend considerable time, effort and expense to improve the fluid handling capabilities of the products.

The fluid handling capabilities of a product can be considered as the ability of the product not only to absorb a fluid but also to channel the absorbed fluid to a preferred location within the product for storage, for example, in products as diapers and feminine care products, the retention of fluid in the interbody between the body and the product is not generally desired.It is generally preferred that such products are designed to absorb rapidly and then pull such fluids out of the inter face between the body / product A layer of material which absorbs rapidly and then moves the fluid out of the body is sometimes referred to as an "affluence" layer, once the fluids have been absorbed and pulled out of the body, the fluids are preferably channeled into and into one or more storage layers. These wrapping layers desirably retain or contain such fluids while minimizing the reabsorption of these fluids by the surge layer. In some cases, the product may be required to support multiple insults or fluid wetting before being replaced. Therefore the designers and engineers of such products are constantly being challenged to develop and / or refine the materials which not only adequately flow, channel and retain the fluids of an initial wetting but also adequately handle the subsequent wetting fluids. The tasks of the designers and engineers become more formidable taking into account (i) the hydrophobic nature of numerous materials traditionally used in the above-mentioned products and (ii) the business and economic realities to produce such products for the disposable markets.

Therefore, there is a need for particularly polymeric materials and materials having improved fluid handling capabilities as well as efficient and economical methods for making them.

SUMMARY DB THE INVENTION In response to the problems encountered above by those skilled in the art, the present invention provides a porous fluid-absorbing structure. The porous structure of the present invention is generally formed of fibers and has a basis weight in the range of at least about 0.25 ounces per square yard to about 10.0 ounces per square yard and a density of at least about from 0.01 grams / cubic centimeter to around 0.15 grams / cubic centimeter. In one embodiment, the porous structure adapts so that with the application of at least 2 milliliters of fluid bovine fluid in oxalate to a surface thereof, substantially all of that fluid enters the volume of the porous structure in about 45 minutes. seconds.

In another embodiment, the porous structure is adapted so that with the application of at least three milliliters of fluid bovine blood in oxalate to a surface thereof, substantially all of the fluid enters the volume of the porous structure within about 100%. 150 seconds The porous structure is further adapted so that after 5 minutes from the time when all the fluid enters the undisturbed volume of said porous structure less than about 25% and more particularly less than about 20% and even more particularly within from about 15 to about 8% of the oxalate and blood fluid coil are retained by said poroa structure.

In another embodiment, the structure includes two layers which are generally in a juxtaposed relationship and in contact with one another. A first porous layer can be formed of fibers and has a basis weight and density within the ranges described above. Desirably, these fibers can be melt-extruded thermoplastic fibers formed by spun bonding and include an internal hydrophilic additive.

The fibers of the first poroa layer can function as to "flow" the fluids in contact therewith. This fiber may be formed and arranged so that the contact fluid is rapidly absorbed by the first layer, distributed within the first layer and pressed through the first layer to the second porous layer.

The second porous layer may be formed so as to receive the aqueous fluid pre-pressed or pushed from the first porous layer The second porous layer may also be formed from melted-extruded thermoplastic fibers and more particularly melted thermoplastic fiber-extruded fibers. The second porous layer can also be formed from natural fibers or from a combination of natural and synthetic fibers.

The extruded-melted fibers of the present invention can be homo-polymeric, co-polymeric, Bi-or multicomponent polymer or polymer blends. In one embodiment, these fibers can also be formed through appropriate processes so that they are spiral shaped.

When the bi-or multi-component fibers, one of the component β can be ho-polymeric, co-polymeric, or a polymer mixture. The orientation of individual components, such as a first and a second component, may be sheath-core or side-by-side.

Desirably, the first component of the multi-component fiber can be formed from a polyolefin and desirably from a polyolefin homo-polymer. And more desirably, the first component can be formed of polypropylene. Another component, or the second component, of a bi-component fiber can be formed of a polyolefin and more desirably of already a linear low density polyethylene., of a high density polyethylene, a copolymer of propylene and ethylene or a combination of polypropylene and polyethylene. The combination of the polypropylene and the polyethylene can be in the form of either a block polymer or a mixture of polymers. When it forms a co-polymer of propylene and ethylene, the percent by weight of the propylene can range from about 90% to about 99.9% and the percent by ethylene peel can vary from about 0.1% to about 10% Desirably, the internal hydrophilic additive suitable for use in the present invention is generally non-toxic and has a low volatility. Additionally, the internal hydrophilic additive must be thermally stable at temperatures up to 300 * C and sufficiently soluble in the melted or semi-melted polymer. The internal hydrophilic additive must be sufficiently phase separated so that the additive migrates from the polymer fiber mass to the surface of the polymer fiber as the fiber cools without requiring the addition of heat. Once on the surface of the polymer, the internal hydrophilic additive desirably changes the hydrophobicity of the polymer surface so that the polymer to which it is added is rapidly wetted upon contact with the aqueous fluid.

Examples of such internal additives include one or a combination thereof selected from the following classes of internal additives: (i) fluorinated alkyls modified with polyoxyalkylene, (ii) fatty acid esters of polyoxyalkylene, (iii) polydimethyl siloxane modified with polyoxyalkylene and (iv) PEG-Terephthalate (polyethylene glycol modified terephthalate). An example of the polyoxyalkylene-modified fluorinated alkyl eß FC-1802, a product of Minnesota Mining and Manufacturing Company. An example of a polyoxyalkylene fatty acid ester is PEG-00ML, a product of Henkel Corporation / Energy Group. An example of a polyoxyalkylene modified polydimethyl siloxane is MASIL SF-19, a product of PPG Industries.

In another embodiment of the present invention, the porous structure includes at least two layers in a juxtaposed and contacting relationship wherein each layer is a non-woven layer formed of extruded-melted thermoplastic fibers. An internal hydrophilic additive as described above may be present in the fiber by forming one or both of the nonwoven porous layers.

A first porous layer can be made of fiber and have a small layer and a denseness within the range of the above-mentioned. The first porous layer can work, to "flow" a water fluid. These fibers can be formed and arranged so that the aqueous fluid which makes contact with these fibers is abosorbed and rapidly distributed into the first layer and finally pushes towards the second porous layer. The pore size of the first porous layer may be larger than the pore size of the second porous layer. The fibers of the first porous layer can be formed by spun bonding.

The second porous layer is formed so that the fiber of the second porous layer receives and retains the aqueous fluid pushed towards the first porous layer. The fiber of the second porous layer can be formed by a meltblowing process. The second porous layer may also have a basis weight and a density within the ranges described above whenever there is a difference in the surface energies and / or the pore size between the first and second porous layers.

In another embodiment, the present invention provides a surgical drape. Surgical draping includes a sheet or sheet that has an opening there. The porous structure is secured to the sheet around and / or to one side of said opening. The porous structure may function to reinforce and / or provide improved aqueous fluid handling. Such aqueous fluids may originate from below or above the opening as well as in a general vicinity thereof.

The porous structure includes at least two porous layers. The two layers are generally in a juxtaposed relation and in contact with each other. A first porous layer can be formed from extruded-melted thermoplastic fibers having a baße weight within the range described above. These fibers can be formed by splicing processes and can include an internal hydrophilic additive as described above.

The fibers of the first porous layer can function as to "flow" an aqueous fluid towards a second porous layer. The melted-extruded fibers of the first porous layer, as described above, can be homo-poly-aryl, copolymeric or bi-component polymeric and can also be helical or spiral.

The fiber of the second porous layer may also be formed of melted-extruded thermoplastic fibers and may have a low density and denseness within the ranges described above. These fibers can be formed by melt blowing and can include an internal hydrophilic additive similar to that mentioned above. The second porous layer can function as an anchoring layer in which case these fibers can be formed and arranged so that this layer can receive and retain the aqueous fluid pushed from the first porous layer. Additionally, the pore size of the first porous layer may be larger than the pore size of the second poroa layer. The fibers of the second porous layer can be either bicomponent or mono-component. If they are mono-component, these fibers can be formed of polypropylene.

In yet another embodiment, the present invention provides a sanitary napkin. The sanitary napkin includes a top cover and a bottom cover that capture a porous three-layer absorbent structure. A part of one of the covers is permeable to the liquid to allow the fluid in contact therewith to enter the absorbent structure.

The intermediate layer of the absorbent structure is in a juxtaposed and contacting relationship with the two outer layers. One of the outer layers may be formed of fiber and may function to flow an aqueous fluid in contact therewith into the middle layer. The fibers forming this influx layer can be similar to the fibers described above to form the other inflow layers.

The intermediate layer can function as a storage layer and can be ßer to the β-β-β-fiber above to form the other storage layers.

The other outer layer may be formed of natural or synthetic fibers, including cellulosic fiber, cotton fiber or regenerated cellulose or co-form fibers. This layer functions to receive and store the fluids of the intermediate layer.

BRIEF DESCRIPTION DB THE DRAWINGS Figure 1 is a cross-sectional view of the absorbent structure of the present invention.

Figure 2 is a biased drawing of a transverse section of a bi-component filament illustrating an array of components from side to side.

Figure 3 is a schematic drawing of a transverse section of a bi-component filament illustrating a sheath / core arrangement.

Figure 4 is a schematic drawing of a process line for making a layer of one of the modalities of the present invention.

Figure 5 is a plan view of a surgical drape that has a window there illustrating the abyssent structure of the present invention placed around the window.

Figure 6 is a view in transverse direction of Figure 5 along the line 5- 5-5.

Figure 7 is a cross-sectional view of a part of a sanitary napkin.

BRIEF DESCRIPTION DB THE INVENTION Referring to FIG. 1, FIG. 1 shows a porous absorbent structure 20 having a first porous layer 22 in a juxtaposed and contacting relationship with a second porous layer 24. The pore size of the first porous layer 22 may be larger than the pore size of the second porous layer 24. The first and second porous layers, 22 and 24 respectively, can be a non-woven fabric formed of fibers, more particularly, the non-woven fabric can be formed from one or more melted thermoplastic polymers. -extrudedß.

As described in more detail below, the first porous layer 22 and the second porous layer 24 can be formed and adapted so that two milliliters of oxalate-blood coil applied to the first porous layer 22 bent completely through the abyssent structure 20 within around 180 ße gun gun y y and particularly, within about 150 ße gun gun gun gun. Additionally, the first porous layer 22 may also be modified so that with the passage of about 5 minutes from the moment when the oxalate-blood-coil enters the undisturbed abyssor structure 20, less than 25% and more particularly less than 20% and even more particularly between about 15 to about 8% of said fluid is retained by the first porous layer 22. The second porous layer 24 can be formed and adapted so that with the passage of about 5 minutes deßde the moment when the oxalate-ßangre coil enters the undisturbed abyssent structure 20, more than about 75% and more particularly about 80% and even more particularly between about 85 and about 92% of said fluid. retained by the second layer poroßa 24.

By way of example only, the thermoplastic polymers may include the end-coated polyacetals, such as poly (oxymethylene) or polyformaldehyde, poly (trichloroacetaldehyde), poly (n.-veraldehyde), poly (acetaldehyde), poly (propionaldehyde) , and the like; acrylic polymers such as poly (ethyl acrylate), poly (methyl methacrylate) and the like; fluoro-carbon polymers, such as perfluorinated propylene-ethylene copolymers, ethylene-tetrafluoro ethylene copolymers, poly (chloro trifluoro ethylene) copolymers of ethylene-chloro trifluoroethylene, poly (vinylidene fluoride), poly (vinyl fluoride), and ßimilareß; polyamide, such as poly (6-amino caproic acid) or poly (e-caprolactam), poly (hexamethylene adipamide), poly (hexamethylene ßbabamide), poly (11-amino undecanoic acid) and ßimilareß; polyaramide, such as poly (imino-l, 3-phenylenediminoissphthaloyl) or poly (g-phenylene isophthalamide), and ßimilareβ; paralinenos, such as poly-g-xylinennes, poly (chloro-p.-xylineno) and the like; polyarylethers, such as poly (oxy-2,6-dimethyl-1,4-phenylene) or poly (p-phenylene oxide) and the like, polyaryl sulfones, such as poly (oxy-1,4-phenylene-phenylphonyl) , 4-phenyleneoxy-1,4-phenylene-1-bisphenylidene-1,4-phenylene), poly (sulfonyl-1, 4-phenyleneoxy-1,4-phenylene-sulfonyl-4, '-biphenylene) and ßimilareß; polycarbonates such as poly (bisphenol A) or poly (carbonyldioxy-1,4-phenylene isopropylidene-1,4-phenylene) and the like; polyesters such as poly (ethylene terephthalate), poly (tetramethylene terephthalate), poly (cyclohexylene-1,4-dimethylene terephthalate or poly (oxy-methylene-1,4-cyclohexylene methylene oxy terephthaloyl), and the like; sulfides polyaryl, such as poly (phenylene sulphide) or poly (thio-1,4-phenylene) and the like, polyimides, such as poly (pyromethylimido-1,4-phenylene) and the like; polyolefins, such as polyethylene, polypropylene , poly (l-butene) poly (2-butene), poly (l-pentene) poly (2-pentene), poly (3-methyl-l-pentene), poly (4-methyl-1-pentene), 1, 2-poly-1,3-butadiene, 1,4-poly-1,3-butadiene, polyisoprene, polychloroprene, polyacrylonitrile, poly (vinyl acetate), poly (binylidene chloride), polystyrene and ßimilareß; β-copolymer of the above such as polypropylene-ethylene, polypropylene-polyethylene, polyethylene-polyvinyl alcohol, acryl-nitrile-butadiene-pyrenean (AVS) acrylonitrile, and ß -imilareß.

The first layer 22 may be a non-woven fabric formed of melted-extruded thermoplastic polymer fiber and have a basis weight of at least about 0.25 oz per square yard and a density of at least about 0.01 gram per centimeter. cubic. More particularly, the peigno baße and the denseness of the first layer 22 can vary from about 0.25 to about 10.0 ounces per square yard and between about 0.01 to about 0.15 grams / cubic centimeter, respectively, and even more particularly from between about 0.5 to about 5 ounce per square yard and about 0.01 to about 0.1 grams / cubic centimeter, respectively and still more particularly between about 1.0 to about 3 ounce per square yard and about 0.01 to about 0.08 grams / cubic centimeter, respectively. The fibers forming the first layer 22 may also include an internal hydrophilic additive. Alternatively, the first layer can be formed of a porous thermoplastic film having an internal hydrophilic additive or porous foam having an internal hydrophilic additive.

The first layer 22 may be adapted in a manner with the application of at least two milliliters of oxalate-ßangre fluid coil to a surface thereof, ßubstancially all that fluid enters the mass of the porous structure in about 45 seconds. The first layer 22 can also be adapted in a manner (with the application of at least 2 milliliter of oxalate-ßangre fluid coil to a surface thereof sub-substantially all the fluid enters the mass of the porous structure within about of 150 seconds and because after about 5 minutes from the time when all the fluid enters the undisturbed mass of the first layer 22, it is around 25% and more particularly less than about 20%, and even more particularly between about 15 to about 8% of the oxalate-blood fluid coil is retained by the first layer 22.

Desirably, the layer 22 pyrma is a non-woven fabric which can be formed through a variety of processes including, but not limited to, air laying processes, wet laying processes, hydroentanglement processes, spin bonding formed by blown from melting, bonding and carded cut fiber, and spinning of solution; it has been found that the non-wovens formed from the polyester-beßfiber-to-bead are particularly suitable for the applications mentioned above. When the first porous layer 22 is a porous film, said porous film can be formed by any one of the various processors of porous film formation known to those skilled in the art. When the first porous layer 22 is a porous foam, said porous foam may be formed by any of the various foam forming processes known to those skilled in the art.

There are several types of polymer fibers useful for forming the first porous layer 22. Such fibers can be homo-polymeric, co-polymeric, Bi-or multicomponent polymer or a mixture of polymers. Polymers particularly well suited for forming such fibers include, for example, polyolefins, polyesters, such as PET, PVT, and PBT, rayon, and polyamides such as nylonon. More particularly, examples of suitable polyolefins include polypropylene and polyethylene, and combinations of polymers, such as polypropylene / polyethylene, polypropylene / ethylene and polypropylene / polybutylene.

With the continued reference to Figure 1, the fibers of the first porous layer 22 can function as "influx" fluids in contact therewith. These fibers can be formed and arranged so that the fluids which make contact with this fiber are rapidly absorbed and are distributed inside the first porous layer 22 and once in the mass of the first porous layer, they push towards the second layer. poroßa 24 as ß deßcribe in more detail below. In a modality, the fiber of the first porous layer 22 is formed by spun bonding so that the resulting fibers are virtually continuous.

The second porous layer 24 can be formed so that the pore size and / or the surface energy of the second porous layer 24 differs from the first porous layer 22. Generally, it is desirable that the pore size and / or the The surface energy of the first porous layer 22 is greater than the surface energy and / or pore size of the second porous layer 24. In this manner, the second porous layer 24 can receive and distribute the pushed aqueous fluid from the first layer. poroßa.

The second porous layer 24 can also be formed of the melt-extruded thermoplastic fibers described to form the fibers of the first porous layer 22. More particularly the second porous layer 24 can be formed of melted-extruded thermoset fibers which are formed by the former. blown from melted. The second layer 24 can have a basis weight of at least about 0.25 ounces per square yard and a density of at least about 0.01 grams / cubic centimeter. More particularly, the peigno baße and the denseness of the first layer 22 can vary from about 0.25 to about 10.0 ounce per square yard and about 0.01 to about 0.15 grams / cubic centimeter, respectively and even more particularly from around 0.5 to about 5 ounce per square yard and about 0.01 to about 0.1 gram / cubic centimeter, respectively, and even more particularly between about 1.0 to about 3 ounces per square yard and about 0.01 to about 0.08 g. / cubic centimeter, respectively.

In some embodiments, the meltblown thermoplastic fibers that form the second porous layer may have a diameter range of from about 0.2 to about 10 microns. The fibers forming the second layer can also form natural fiber, such as, for example, cellulose fibers, wood pulp fibers, regenerated cellulose, cotton fibers, hydroentandered fluff pulp, fluff pulp, tissue and the like. Additionally, the fibers forming the second porous layer can also form a combination of synthetic fibers and natural fibers. Such a combination of natural and synthetic fibers is generally mentioned as co-form fibers.

Additionally, the thermoplastic meltblown fibers that make up the second layer can also be Bi- or multi-component β fibers. The thermoplastic fibers formed by meltblowing of Bi- or multicomponent and the methods for making them are described in the patents of the United States of America 5,238,733, 5,232,770, 4,547,420, 4,729,371, and 4,795,668, all laß cualeß ße yielded to Minneßota Mining and Manufacturing Company and here they are incorporated by reference.

The concepts of absorbing and distributing a fluid within the first porous layer can be better understood by reference to the laß lineaß labeled A1, B1 and B2 in layer 22 and to the lines labeled A, B, and B_ in layer 24. lines A1 represent the displacement of fluid within layer 22 along the z-axis while lines B1 and B2 represent the displacement of fluid within layer 22 along axes x and several depths within layer 22. It will be understood that while the behavior of the fluid flow for the purposes of illustration of Fig. 1 is explained by a fairly general three-dimensional model, a more accurate explanation of the behavior of the fluid flow is possible and the use of a three-dimensional model will be required. generally more complex.

Additionally, by varying the lengths of each such line, ß attempts to illustrate the fluid flow and depth of penetration into the layers 22 and 24 in the respective directions over a period of time elapsed. For example, by illustrating the line A1 as having a length greater than that of the line B1, it is suggested that by contacting the upper surface 26 of the first layer 22 with a fluid and the passage of a period of time, a greater quantity of such a fluid ε moves along the z-axis, the line A1 that along the axis x and y, the line B1, in the relative position of the line B1 within the first layer 22. traditionally, since the length of line B2 eß greater than that of line B1, ε suggests that as the fluid passes through the mass of first layer 22 along the z axis, the migration or distribution of such fluid within the core of layer 22 as length of the axis x and y increases.

In addition, with the passage of sufficient time so that the fluid contacting the first layer 22 crosses the interface 28 of the first and second layers, 22 and 24, respectively, there occurs a greater distribution of fluid in the second layer there. 24 along the axes x and y is ilußtra on the ß line β B, and Bj along the z axis, as ε ilußtra on the line A ,.

Thus, even though the first layer 22e generally mentions as an "inflow" layer which suggests a significant fluid movement along the z axis the fluid distribution along the axes x and y, within the first layer 22 before such a fluid makes contact with the second layer 24 is also desirable. For example, an inflow layer that provides minimal fluid distribution along the x and y axes generally results in a focused or generally located reservoir of such fluid at the interface of the surge layer and a storage layer. To prevent stagnation or drainage of fluid, the fluid flow in the z direction of the storage layer, in this case, the second layer 24, must be suitable for a fluid intake in the interface 28 before the stagnation or runoff. A flow of fluid in the proper z-direction is achieved by varying the pore size and / or the surface energy of the storage layer with respect to the boiling layer so that the value of the surface energy and / or the pore size of the storage layer is smaller than that of the emergence layer.However, in this example having sufficient fluid flow in the z direction of the storage layer may not be achieved without an exchange to the flow of the storage layer. fluid in the x directions x and y of the same layer., providing such sufficient fluid flow in the z direction can reduce fluid flow in the x and y directions and thereby reduce the fluid storage capacity of the storage layer. A solution to recapture the lost storage capacity is to make a storage layer generally thicker and higher. However, there are several disadvantages to this solution. Some of these disadvantages include additional time and additional manufacturing costs and a bulkier absorbent product.

This problem can be avoided by providing an inflow layer which not only allows adequate fluid movement along the z-axis but also along the axis x and y. In this way the localized deposit of the fluid on the storage layer is avoided. As such, the fluid that passes through the ßurgery layer is deposited over a larger area along the interface between the emergence layer and the storage layer. Also, such a fluid reservoir at the interface of the inflow and storage layers may allow the use of a thinner or less raised storage layer. This is so because the requirement for the movement of fluid along the z-axis in the storage layer is reduced by the migration of such fluid along the axes x and y of the contact flow layer of such fluid. with the storage layer.

Another advantage of a sufficient fluid movement along the axes x and y of the emergence layer is an improved spotting masking without the addition of a separate spotting masking layer. Improved stain masking is achieved by avoiding a localized deposit of a fluid that stains from the bursting layer on the storage layer. A sufficient fluid distribution along the axes x and y within the inflow layer before the transfer to the storage layer disperses the staining fluid over a larger area which at the same time reduces or dilutes the color intensity of such fluid .

Referring now to FIGS. 2 and 3, when the figures 30 form the first layer 22 are bi-component, the first and second components A and B can be arranged in a side-by-side orientation as is illustrated in FIG. 2 or FIG. in a sheath / core orientation as illustrated in figure 3.

Referring now to Figure 2, even though the component A and B of the bi-component fiber 20 are illustrated as being virtually equal in orientation ratio around the fiber 30 it will be understood that side-by-side orientation occurs when a part of such component a and b, they share a portion of the periphery of the fiber through virtually the entire length of the fiber 30. Referring to Figure 3, it will be further understood that the arrangement of components A and B in a sheath / core orientation occurs when one of the components occupies the entire periphery of the fiber 30 through virtually the entire length of Figure 30.

In addition, in the case of bi-component fibers, the first and second component may be homo-polymeric, co-polymeric or a mixture of two or more different polymers.

Desirably, the first component A of the bicomponent fiber 30 is formed of a homopolymer. And more desirably, the first component A is formed of polypropylene. Desirably, the second component B of the bi-component fiber 30 can be formed of either a linear low density polyethylene, high density polyethylene, a copolymer of propylene and ethylene or a combination of polypropylene and polyethylene. The combination of polypropylene and polyethylene can be in the form of a polymer or block polymer mixture. When formed of a copolymer of propylene and ethylene, the propylene byproduct varies from about 90 to about 99.9, and the percent by weight of ethylene varies from about 0.1 to about 10 and more particularly the percent by weight. of propylene varies from about 95 to about 99.5 and the percent by weight of ethylene varies from about 0.5 to about 5.0. Even more particularly, the percent by weight of propylene can range from about 96 to about 98.5 and the percent by weight of ethylene ranges from about 1.5 to about 4.0. When the second component B is formed of a combination of polypropylene and low density polyethylene, the percentage per polypropylene peel varies from 20% to about 80% and the percent by weight of the low density polyethylene varies from about 20%. % to around 80%.

In some cases, the bicomponent polymeric β-strand β-fiber may also be formed, by appropriate process, and either in a β-shape spiral fiber or in a helical fashion. When the eßpiral form eßeséeada, the polymer components, A and B, are generally selected so that the resultant bi-component filament is able to develop a natural spiral. This is achieved by selecting the components of polymer A and B so that each component has a sufficiently different melting temperature. For example, when the component A is formed of polypropylene, the component B is formed of polyethylene, the bi-component fiber 30 may comprise from about 20% to about 80% by polypropylene binder and from about 20% by weight. to around 80% polyethylene. More particularly, such fibers may comprise from about 40% to about 60% by polypropylene and from about 40% to about 60% by polyethylene. A desirable method for forming the suitable polymeric components β and B in a spiral-shaped fiber is the process line 40 illustrated in Figure 4. Even though the process line 40 ε will describe how to form a fiber having β-component β, it should understand (where the fiber produced by the process line 40 may be formed from a plurality of components in excess of two.

The process line 40 includes a pair of melt extruders 42a and 42b to separately heat, melt and extrude the melted polymer components A and B. A first hopper 44a supplies the component A within the burster 42a. A second hopper 44b supplies the component B within the tool 42b. The temperature of each extruder will vary depending on the nature of each particular polymer. As such, the temperatures of each heater, 42a and 42b, can vary from about 370"F to about 530 * F and more particularly can range from about 400 * F to about 450 * F.

When a bi-component fiber is formed, the hydrophilic internal additive described in greater detail below may be added to the polymer melt in one of several ways. Generally, the concentration of the internal additive in the bi-component fiber eß of between about 0.1% to about 5.0% and specifically between about 0.25% to about 5.0% and more specifically between about 1.0 to about 1.5% of the combined weight of components A and B. It has been found that when the internal additive is present at concentrations of 0.25% by weight, or less, additional heat may be required to cause the internal additive to migrate to the surface of the fiber. Generally the additional heat can be applied once the fibrous tissue has formed. Desirably, an internal additive, described in more detail below, can be formulated with a thermoplastic which can be blended in ε through the introduction into any of the β-hoppers containing the polymer 44a or 44b in a predetermined proportion β to give the concentration of desired internal additive. Another method for adding the internal additive is through the metering of an additive amount of additive directly into one or both of the estruders, 42a or 42b.

The polymer components A and B exit their respective extruders, 42a and 42b and enter into respective conduits 46a and 46b. These conduits converge inside a spinning organ 48. The spinning organs for extruding the bi-component fibers, in any side-by-side or sheath / core orientation, are very well known and generally include a housing containing a spin pack. illustrated). The spin pack includes a plurality of plates stacked one on the other with a pattern of apertures arranged to create flow paths for directing polymer components A and B through the spinner 48. As a result of this, a curtain of bicomponent fibers 49 is extruded from the spinner 48.

A blower 50 is placed near the curtain of bicomponent fibers 49. Upon exiting the fibers of the bicomponent 49 of the spinner 48, a flow of cooling air (generally perpendicular to the filaments and between about 45 * F to about from 90 * F to a flow rate of about 100 to 400 ft² / ße second) of the op lador 50 50 hace 50 makes contact with the fibra 49 fiber. As the bicomponent fiber is cooled, these fibers develop a latent spiral ripple.

A suction or fiber pulling unit 52 is placed about 30 to 60 inches below the bottom of the spinner 48. The unit 52 receives the cooled two-component fiber 49. Such units which are suitable for use in the line of process 40 ßon of the type shown in U.S. Pat. Nos. 3,802,817, 3,692,618 and 3,423,266, the descriptions of which are incorporated herein by reference.

Generally described, the fiber pull unit 22 includes an elongated vertical screen through which the bi- component bi-component fiber is pulled by sucking in air from the sides thereof and flowing through such a pad. A heater 54 supplies the suction air to the fiber pulling unit 52.

The temperature of the air supplied from the heater 54 is sufficient to heat the fibers 49 to a temperature sufficient to activate the latent spiral ripple. The temperature required to activate the latent eßpiral range eß of about 60 * F at a lower maximum temperature than the melting point of the lower melting component.

The air temperature of the heater 24 and therefore the temperature at which the fibers 49 ß heat up can be varied to achieve different degrees of spiral. Generally, by adjusting the temperature of the air produced by the heater 54, one can alter the den denity, the pore size distribution and the draping of the final product.

An endless foraminous forming surface 56 is positioned to receive the spiral bi-component fibers 49 from the fiber pulling unit 52. The forming surface 56 is displaced around the guide rollers 58. The bicomponent spiral fibers 49 are pulled in against the forming surface 56 by a vacuum 60. The bicomponent fiber spirals 49 are pulled against the forming surface 56 by a vacuum 60.

The bi-component fibers 49 are compressed before leaving the forming surface by a compression roller 62. The bicomponent compressed fiber fibers 49 can be joined such as thermal bonding by the rolls 64 or joined through air by means of the structure 66. The air-through linker 64 generally includes a perforated roller 68, which receives the fabric and a cover 70 that surrounds the roller 68.

Generally, the temperature of the air in the air viaator 66 is above the melting point of the melting point component lower but below the melting point of the melting point component of the point component. of melted ßuperior. In this manner, the bicomponent fibers are joined together by contact between the lowest melted point components. A winding roller 72 collects the finished product.

It will be understood that other embodiments of the present invention may include an absorbent structure having more than two layers.These additional layers may be porous or non-porous woven or non-woven, permeable or impermeable films, foams or a combination thereof.

The layers of the absorbent structure can be combined by various methods to form the juxtaposed and contact relationship described above. For example, the layers of the absorbent structure of the present invention can be formed separately and then laminated together or one layer can be formed directly on the upper part of another.

Alternately, the ß layer can be formed in ßerie, ßimultaneously, by placing the layer ß that form the units in series. This layer can also be ßer unidaß. Bonding can be achieved by various methods including, for example, hydroentanglement, perforation, ultrasonic bonding, adhesive bonding and thermal bonding.

When the two layers are formed in line and the first layer is formed of a polypropylene / polyethylene bicomponent fiber, the second layer may include a mixture of polypropylene and polybutylene, as disclosed in the United States of America patent number. 5,204,174 assigned to Kimberly-Clark Corporation and incorporated herein by reference. Generally, the weight percent of the polybutylene in the second layer can vary from about 5% to 50% and particularly from 15% to 40% and more particularly from 30% to 40%. Generally, the addition of polybutylene to the fibers forming the second layer provides improved adhesion between the fibers of the first and second layers while maintaining sufficient porosity at the interface of this layer.

A suitable internal additive, such as an internal hydrophilic additive, for use in the present invention is generally non-toxic, has low volatility and is sufficiently soluble in the melted or semi-melt polymer.

In addition, the internal additive is thermally stable at the temperature of 300 ° C and efficiently so that the additive migrates from the mastic of the polymer fiber to the surface of the polymer fiber when the fiber is cooled without requiring the addition of heat. Once on the surface of the polymer, the internal additive changes the hydrophobicity of the polymer surface so that the surface of the polymer is rapidly moistened upon contact with the aqueous fluid, such internal additives include one or a combination of internal additives selected from The following classes of internal additives are: (i) fluorinated alkyls modified with polyoxyalkylene (ii) fatty acid esters polyoxyalkylene, (iii) polydimethyl siloxanes modified with polyoxyalkylene and PEG terephthalate (polyethylene glycol modified terephthalate) An example of a fluorinated alkyl modified as polyoxyalkylene eß FC-1802 An example of the polyoxyalkylene fatty acid ester is PEG-400 ml An example of the polyoxyalkylene-modified polydimethyl siloxane is MASIL1 * SF-19 In another embodiment of the present invention, the internal hydrophilic additive can be present in the thermoplastic fibers forming one or both of the layers porous above described.

Generally the concentration (percent by weight of the fiber) and the internal additive in the fibers is between about 0.1% to about 5.0% and more specifically between about 0.25% to about 5.0% and more specifically to about 1.0. to around 1.5%. It has been found that when the internal additive is present at a concentration of 0.25% per fiber fiber or less, additional heat may be required as discussed above, to cause the internal additive to migrate to the surface of the fiber.

Referring now to Figure 5, a surgical drape 510 is illustrated. Surgical drape 510 includes a sheet 512 having portions thereof defining an opening 514. Opening 514 is generally designed to lie on the patient's operating site to provide the health care provider with access means to the site. It will be understood that while draping 510 is shown in Figure 5 as being generally rectangular in shape, the present invention is equally well suited for use in drapes having a variety of shapes and sizes. The porous structure 516 may function to reinforce the drape 510 and / or provide improved fluid handling around and near the opening 514.

A porous structure 516 is secured to the sheet 512 around and / or to one side of the opening 514. Referring now to Figure 6 the porous structure 514 is formed of 3 layers of material 518, 520 and 522. The layer 518 is desirably a non-porous film that is impermeable to liquid. By way of example only, such film suitable for ußarße in the present invention includes a Catalloy film. The thickness of layer 518 can be from about 0.5 to about 2.0 mils, and more preferably from about 0.75 to about 1.25 mils.

Layer 518 may be secured to sheet 512 and layer 520 by various methods which are well known to those skilled in the art. Particularly, such securing methods may include the application of the hot or aqueous fused adhesive to the surfaces of the layer 518.

The layers 520 and 522 ßon ßimilareß in both form and function to the second and first porous layers ß and first 24 and 22, respectively, which are described in detail above. As such, the layer 522 functions to absorb, distribute and rapidly push the fluids (they come in contact with it) The layer 520 functions to receive and distribute the fluids pushed thereto by the layer 522. The layer 518 functions to prevent fluids received and distributed by layer 520 from contacting sheet 512.

Referring now to Figure 7, an absorbent article 710, such as for example a sanitary napkin is illustrated in the cross section. An upper cover 712 having a perforated portion 714, and a liquid impermeable bottom cover 716 captures a multi-layer laminated abyss binder structure 718.

The multi-layer laminate structure 718 includes two outer layers 720 and 724 separated by an intermediate layer 722. The layers 720 and 722 are ßimilareß in both form and function to the first and second porous layerε 22 and 24 respectively which are described in detail above.

The layer 724 can be formed of natural or synthetic fibers, including cellulose fibers, melted-extruded fibers treated with ßurfactant, wood pulp fiber, cotton or regenerated cellulose fibers, or fiber coform, laß cualeß ßon a mixture of pulp and made of synthetic fiber meltblown. The desired materials for ußarße in a ßanitary towel ßon erases wood pulp and fiber-co-form. An important function of the layer 724 is that of providing the fluid storage capacity for the absorbent article 710.

In operation, the fluid entering the absorbent article 710 through the perforations in the part 714 contacts the layer 720. The fluid which contacts the layer 720 is absorbed, distributed and pushed as described above. The fluid pushed from the layer 720 to the layer 722 is absorbed and distributed within the layer 722. Accordingly, the fluid flow characteristic of the layer 722 is that the fluid at the interface between the layer 720 and 722 is absorbed by layer 722 and then push towards and absorb through layer 724.

Stain masking can be improved by distributing improved fluid in the z-axis of the sprouting layer. In the case of the absorbent article 710, the stain masking is further improved not only by the improved fluid distribution in the z axis of the 720 layer but also by improving the fluid flow characteristics in the x, y, y axes of the layer 722 antee of the fluid reservoir ßobre layer 724. In this way a sufficient part of the staining fluid that initially makes contact with the layer 720 ße finally contains layer 724 and not ßobre capaß máß vißibleß 720 and 722 of the article absract 710.

The following examples demonstrate the improved fluid handling capabilities of the present invention. Such examples, however, should not be considered as limiting in any way the spirit or scope of the present invention.

EXAMPLE 1 In order to illustrate the above invention, a three-layer laminate was formed which consisted of a first porous layer, a second porous layer and a film layer. The first porous layer was a spunbond fabric (SB) formed according to the following descriptions.

DESCRIPTION DB UNITED WITH YARN: Filament configuration: bi-component side by side Spinning hole geometry: 0.6mm D. 4: 1 Vn Polymer A: Exxon 3445 100% polypropylene (homopolymer) Polymer B: Exxon 9355 random copolymer 3% ethylene (97% polypropylene) A / B ratio: 50/50 Melting temperature (F): 430 * F (both) Production of spin hole (GHM): 0.5 - 0.9 ghm (grams / hole / minute) Flow QA (SCFM / inch): 45 Temperature QA (F): 55-65 * F Delivery air temperature (F): 160'F Type of union: Thermal wire weave pattern Bonding temperature: 245 * F Ounce per square yard: 0.7 to 1.0 ounces per square yard Denier: 2.0 - 3.0 dpf Caliber: 0.026"inches (same as" gauge ") Density: 0.052 Hydrophilic Internal Additive: MASIL * "SF-19 added to both polymer A and polymer B. The total concentration of MASIL * SF-19 present in the fabric was 1.25% by weight.

The second porous layer was a layer formed by meltblown (MB) formed according to the following specifications: FORMED BY MELTING MELT Base weight: about 2.0 ounces per square yard Type of polymer: Exxon 3746, polypropylene melt flow rate 800 or melt flow rate polypropylene 400 Himont PF-015.

Fiber size: 2.0 - 3.0 microns.

Melting temperature: 465"F Production: 3.0 pih (pounds per inch per hour through the spinning die) DESCRIPTION DB THE FILM Type of film: "CATALLOY" Edißon Plaßticß of 1.0 thousand.

Melt point: 230 - 248 * polyethylene component, and 329 * for the polypropylene component.

The first, second and film layers were joined with pins together by the following deßcripcioneß: Type of laminated joint: Thermal, "Ramish" pattern.

Laminate bonding temperature: anvil 200 * F (film side) pattern 280 * F (SB side).

Laminate bonding pressure: 900 psig In addition to joining the first, second and film layers together, the aforementioned laminate was also used to secure all the three layers to the binder window fabric with the film backing.

EXAMPLE 2 A three layer laminate was formed which was similar to the laminate of Example 1 except that the laminate was bonded through air at 270 * F.

EXAMPLE 3 A three layer laminate was formed which was similar to the laminate of Example 1 except that the unit layer per spin was formed of bi-component fiber wherein polymer A was polypropylene and polymer B was polyethylene.

EXAMPLE 4 A three layer laminate was formed which was similar to the laminate of Example 3, except that the laminate was bonded through air at 270 * F.

EXAMPLE 5 A double-layer laminate structure, according to the previous invention, also formed and included a first porous layer and a second porous layer. The first layer poroßa ße formed from a spunbonded fabric (SB) formed according to the following specifications.

DESCRIPTION OF JOINT BY YARN Filament configuration: round S / S Spinning hole geometry: .6mm D, 4: 1 L / D Polymer A: 98% Exxon 3445 (Polypropylene) 2% TiOz Polymer B: 98% Dow 68HA (Linear Low Dense Polyethylene) 2% TiO, Melting temperature (F): 450 * F Yarn hole production (GHM): 0.6 Flow QA (SCFM / inch): 45 Temperature QA (F): 65 Supply air temperature (F): 160 Type of connection: Through air.

Bonding temperature (* F): 262 Base weight (ounce per square yard): 1.0 Denier: 3.0 Ripple type: Helical Density (g / cc): 0.053 Caliber (inch): 0.444 Internal hydrophilic additive: FC 1802 (2.0% by weight) The second porous layer was formed from the meltblown formed fabric constituted according to the following specifications: DESCRIPTION DB BL BLOWN DB MELTED The fabric formed by melt copying (MB) was attached through air to the spunbonded layer through an in-line process. The meltblown formed fabric formed of: 40% Duraflex DP8910 (6% ethylene, 94% butylene copolymer), a product of Shell Chemical Company of Houston, Texas; 30% PD 3445 polypropylene available from Exxon of Houston, Texas; 2% FC-1802; and 28% polypropylene reactor granules having about 500 ppm of peroxide applied thereto. The density of the resulting meltblown fabric was .115 g / cc. The pebble of the fabric formed by melted melted fue fue fue fue was 1.54 ounces per square yard.

EXAMPLE ß To illustrate the improved fluid handling provided by the present invention, the products of Examples 1-5 were compared to other absorbent structures, which will be described in greater detail below. Each sample of absorbent structure was cut into squares (either 8 inches by 8 inches or 5 inches by 5 inches). The samples were placed on a horizontal surface with the unit layer by spinning or the foam layer facing upwards. Two milliliters of oxalate-blood coil were supplied over the center of each mueßtra and the time required for the oxalate-blood coil absorbed completely within the mueßtra.

The oxalate-ßangre coil was provided by Cocallco Biologicals, Inc. of Reamstown, PA. and consisted of red blood cells coil in ammonium oxalate / potaßio. Ammonium oxalate / potassium works as an anticoagulant and is present in sufficient quantities to prevent red blood cells from coiling.

Once the time required to completely absorb the oxalate coil in the wall was reached, the lattice was left unturned for an additional 5 minutes after which the layer was joined by spinning and the layer formed by blowing. of melt from laß mueßtraß 2, El, E2, E3, E4 and E5 were deßlaminadaß.The average diameter of the pre-existing spot ß on each of these layers was measured.The data mentioned above were recorded to Table 1.

TABLE 1 Average Foam Time SB Average MB Absorption Spot Stain Spot 1 14 min 30 sec 9.6 cm 2 5 min 45 sec 2.9 cm 9.3 cm E3 6 sec 4.8 cm 8.9 cm E5 9 sec 5.8 cm 7.5 cm The 25 sec 5.1 cm 7.0 cm E2 17.5 sec 4.6 cm 7.9 cm E5 9 sec 4.5 cm 10.8 cm Sample 1 is a two-layer laminate (with a 1.5-mil polyethylene film adhesively bonded to a 0.040-inch polyurethane foam.

The model 2 is a 3 layer laminate (you have a 1.0 mil polyethylene film bonded to a 2.65 oz polypropylene meltblown layer per square yard and a 1.0 oz polypropylene yarn bonded layer per yard) square, ultra-sonically bonded to the layer formed by meltblowing. A hydrophilic surfactant, GEMTEX * SM-33 SE was applied topically to both the layers joined by spinning and formed by meltblowing the sample 2. The SM-33 is a surfactant of dioctyl-bodic sulfo-succinate and dihydrogenase available through Finetex, Inc. of NJ About 1% by weight of the SM-33 was applied to the melt-blasted layer and about 0.3% by weight of the SM-33 was applied to the layer attached by spinning.

The sample El is the laminate of example 1.

The door E2 is the laminate of example 2.

The wall E3 is the laminate of example 3.

The screen E4 is the laminate of example 4.

The door E5 is the laminate of example 5.

EXAMPLE 7 The percentage of fluid retention was also measured for the spunbonded layer and formed by delaminated meltblown of samples E2 and E5. The percentage of fluid retention was determined by weighing and then comparing the wet layer layer with the dry layer layer. The data are reported in Table 2.

TABLE 2 Flow% Fluid Retention E2-SB 8 E2-MB 92 E5-SB 11 E5-MB 89 E2-SM - Spunbond layer of Example 2. E2-SM - Layer formed by meltblown of Example 2. E5-SM - Spunbonded layer of Example 5. E5-SM - Layer formed by meltblown of Example 5. EXAMPLE • Laß mueßtraß of the spunbond fabrics were obtained and the described analysis of the absorbency, stain and fluid retention described in Examples 6 and 7 ß was performed on the same. The spunbond layers were formed of bicomponent fiber, where polymer A was polypropylene and polymer B was polyethylene. The bi-component spunbonded layers of Example 8 were prepared in a similar fashion to the spunbond layers of Examples 3 and 4 except that this spunbond layer was not bound to a fabric formed by meltblown and subsequently they delayed. The blotting paper was placed under each of the layers joined by spinning before wetting with oxalate-ßange coil.

The fabrics linked by spinning were analyzed: 1.0 oz tissue per square yard and 1.6 oz tissue per square yard. The data are reported in Table 3.

TABLE 3 Moves Time of Absorption Diameter% Retention Spot 1. 0 ounce per yard2 < 1 sec 8 7.4 cm 1.6 ounce per yard2 < 1 ßeg 14 7.1 cm It was noted that the average spot diameters for the samples mentioned above are similar to the stain diameters for the layers formed by melt blending reported in Table 1. The reason for this is believed to be the drying paper used in the Example 8 provided a limited absorption of the bobbin fluid.As such a larger quantity of the bobbin fluid remained in the interface between the blotting paper and the spinning paper for an extended period of time rather than the ßer absotted within the paper. paper.

EXAMPLE 9 A pattern of a spunbonded fabric and a co-form model (75% polypropylene bonded by spinning and 25% cellulose) were obtained and the stain absorbency and fluid retention analysis described in examples 6 and 7 made ßobre the same. Both patients were treated topically with SM-33 (about 1% per pet).

The spunbonded sample was a 1.0 oz. Per square yard fabric having a density of 0.052 g / cubic centimeter and formed of polypropylene. The spunbond fabric of Example 9 is similar to the unit layer by spinning of the screen 2 described above. The co-form sample was a 2.8 oz tissue per square yard having a density of 0.037 g / cc. The data are reported in Table 4.

TABLE 4 Sample Time of Absorption Diameter% Retention Spot av. SB 2 min 42 sec 11 3.1 cm Co-form 1 min 03 sec 78 7.2 cm The examples given above and the test results indicate that the absorbent structures made in accordance

Claims (26)

with the present invention, they have the character of ßuperioreß fluid handling as well as characterization of ßuperioreß spotting enamelcation. Even though the invention has described in detail with respect to the modalities of the specification of the same, it will be appreciated by those skilled in the art, to achieve a v understanding of the foregoing, that they can readily conceive alterations, variations and equivalents of these modalities, therefore, the scope of the present invention should be established as that of the attached clauses and any equivalents thereof. CLAIMS Having described the invention is considered as a novelty and therefore the content of the following clauses is claimed as property.

1. A porous structure capable of absorbing at least three millimeters of blood fluid coil in oxalate in less than 45 seconds and having: a deficiency of at least around 0.01; and a small bar of at least around 0.25 ounce per square yard.

2. The porous structure as claimed in clause 1, characterized in that the porous structure is formed of fibers.

3. The porous structure as claimed in clause 2, characterized in that the fibers include a thermoplastic material and a hydrophilic additive.

4. The porous structure as claimed in clause 3, characterized in that the thermoplastic material is selected from a group consisting of polypropylene, polyethylenes, polyesters, rayons and polyamide.

5. The porous structure as claimed in Clause 3, characterized in that at least some of the fiber β-fiber bi-component.

6. The porous structure as claimed in clause 5, characterized in that the bicomponent fiber comprises a homopolymer and a random copolymer.

7. The porous structure as claimed in clause 5, characterized in that a first component of the bi-component fiber is the polypropylene and a second component of the bi-component fiber is selected from the group of low-density polyethylene. linear, high dense polyethylene, a copolymer of propylene and ethylene or a combination of polypropylene and polyethylene.

8. The porous structure as claimed in clause 2, characterized in that the hydrophobic additive is selected from the group consisting of fluorinated alkyls modified with polyoxyalkylene, polyoxyalkylene fatty acid esters, polyoxyalkylene modified polydimethylsiloxanes and polyethylene glycol modified terephthalates.

9. The structure poroßa (jue comprises: a first layer comprising the porous structure of clause 1; Y a second porous layer juxtaposed on and in contact with said first porous layer.

10. The porous structure as claimed in clause 9, characterized in that the first porous layer is formed of thermoplastic-extruded fiber, which includes a hydrophobic additive.

11. The porous structure as claimed in clause 9, characterized in that the second porous layer is formed of fiber and in about 5 minutes after the application of said fluid, between about 8% and about 14% of the said fluid is present in the first porous layer and between about 92% to about 86% of the pre-active fluid in the second porous layer.

12. The porous structure as claimed in clause 11, characterized in that the second porous layer is formed of melted-estruded thermoplastic fibers and has a density of at least about 0.01 g / cc and a minimum of at least one bar. of 0.25 ounces per square yard.

13. The porous structure as claimed in clause 9 characterized in that the first porous layer is formed of melt-extruded thermoplastic fibers having a hydrophilic additive and is adapted to push an aqueous fluid in contact therewith into the second porous layer; Y wherein the second porous layer is adapted to receive said aqueous fluid from the first porous layer.

14. The porous structure as claimed in clause 13, characterized in that some of the thermoplastic fibers (which form the first porous layer of thermoplastic bi-component fiber having a first polymer component and a second polymer component.

15. The porous structure as claimed in clause 14, characterized in that the first component is a homopolymer and wherein the orientation of the first and second polymer components is generally side by side.

16. The porous structure as claimed in clause 15, characterized in that the homopolymer eß polypropylene.

17. The porous structure as claimed in clause 14, characterized in that the second polymer component is formed of polypropylene and ethylene and that the percent by weight of the polypropylene is at least 90% and the percent by weight of ethylene is at least 0.1%.

18. The porous structure of clause 8, where the hydrophilic additive is the hydrophilic additive of clause 8.

19. A surgical drape that defines an opening (jue comprises: a porous structure secured to the drape adjacent said opening; wherein the porous structure includes; a first layer comprising the porous structure of the clam 1 formed of thermoplastic β-melted β-extruded β-fiber, a hydrophilic additive present in the melt-extruded fibers of the first layer; a second layer juxtaposed on and in contact with said first layer, and a third layer juxtaposed on the second layer and in counting with said second layer and said drape.

20. The porous structure as claimed in clause 19, characterized in that some of the thermoplastic fibers are thermoplastic bi-component fibers having a first polymer component and a second polymer component.

21. The porous structure as claimed in clause 20, characterized in that the first component is a homopolymer and the orientation of the first and second polymer component is generally side by side.

22. The porous structure as claimed in clause 21, characterized in that the homopolymer is polypropylene and the second component is selected from the group consisting of linear low density polyethylene, high density polyethylene, a copolymer of propylene and ethylene or a combination of polypropylene and polyethylene.

23. The porous structure as claimed in clause 20, characterized in that the second component is formed of polypropylene and ethylene and wherein the percent by weight of polypropylene is at least 90% and the percentage by weight of ethylene is. at least around 0.1%.

24. The porous structure as claimed in clause 19, characterized in that the hydrophilic additive is the hydrophilic additive of the clauula 8.

25. The porous structure as claimed in clause 19, characterized in that the second porous layer is formed of fiber and in about 5 minutes of the application of said fluid, between about 8% and about 14% of the said fluid is present in the first porous layer and between about 92% to about 86% of the fluid is present in the second porous layer.

26. An absorbent article comprising a cover juxtaposed ßobre and in contact with an absorbent structure; where the absorbent structure includes: a first layer comprising the porous structure of clam 1 formed of melted-extruded thermoplastic fibers, a hydrophilic additive present in melted-extruded thermoplastic fibers, a second layer formed of melt-extruded thermoplastic fibers having at least about 5% by weight of the polybutylene and at least about 50% by weight of the polypropylene, wherein said second layer is juxtaposed over and in contact with said first layer , and a third layer juxtapueta ßobre and in contact with said second layer and said cover. In witness whereof I sign the President in Mexico, D.F., on May 12, 1995. ION