MXPA01006647A - Absorbent composites with enhanced intake properties - Google Patents

Abstract

The present invention is directed to absorbent composites having enhanced intake properties. The absorbent composites of the present invention have a Composite Permeability (CP) value at full swelling of greater than about 100 x 10-8 cm2. Further, the absorbent composites of the present invention have a Composite Permeability/3rd Insult Fluid Intake Flowback Evaluation (FIFE) intake relationship, which results in enhanced intake properties. The present invention is also directed to a method of making absorbent composites having enhanced intake properties. The present invention is further directed to absorbent composites and their applicability in disposable personal care products.

Description

ABSORBENT COMPOUNDS WITH INCREASED ABSORPTION PROPERTIES FIELD OF THE INVENTION The present invention is directed to absorbent compounds having increased absorption properties. The present invention is also directed to a method for making absorbent compounds having increased absorption properties. The present invention is also directed to absorbent compounds and their application in disposable personal care products.

BACKGROUND OF THE INVENTION In the manufacture of disposable diapers there is a continuous effort to improve the performance characteristics of the diaper. Although the structure of a diaper has many components, in many cases the operation in use of the diaper is directly related to the characteristics of the absorbent compound contained within the diaper. Therefore, diaper manufacturers seek to find ways to improve the properties of the absorbent compound, including absorbency in use, in order to reduce the tendency of the diaper to slip.

One means of reducing diaper runoff has been the extensive use of superabsorbent materials. Recent trends in commercial diaper design have been to use more superabsorbent material and less fiber in order to make the diaper thinner. However, despite the increase in total absorbent capacity contributed by the addition of larger amounts of superabsorbent material, such diapers frequently still suffer from excessive draining during use.

One reason why diapers with a high content of superabsorbent materials that still drain is that many absorbent materials are unable to absorb a liquid at the rate at which the liquid is applied to the absorbent during use. The addition of the fibrous material to the absorbent compound improves the runoff of an absorbent compound by temporarily retaining the liquid until absorbed by the superabsorbent material. The fibers also serve to separate the particles from the superabsorbent material so that gel blocking does not occur. As used herein, the term "gel blocking" refers to the situation in which the particles of the superabsorbent material deform during swelling and block the gap spaces between the particles or between the particles and the fibers, thus avoiding the flow of liquid through the interstitial spaces. Even when the fibrous material is incorporated into an absorbent compound, a poor lesson of a superabsorbent material, especially one which exhibits gel blocking behavior within the absorbent compound, results in poor liquid handling properties initially and then in the cycle of life of the absorbent compound. Consequently, the choice of the materials of the absorbent compound greatly affects the absorbency in the use and in the run-off of the absorbent product.

Another problem with commercially available diapers is the tendency of diapers to drain after multiple discharges. As used herein, the term "discharge" refers to a single introduction of the liquid to the absorbent composition or diaper. During use, a diaper is typically exposed to multiple discharges during the life cycle of the diaper. In order to reduce diaper run-off during the diaper life cycle, it is desirable to maintain the absorbency performance level of the absorbent during the life of the product.

A number of patents from the United States of America refers to different problems associated with absorbent compounds. For example, U.S. Patent No. 5,304,161 issued to Noel and Ahr teaches the use of a multi-layer absorbent structure in which a higher acquisition / distribution layer exhibits a rapid liquid acquisition rate. The patent of the United States of America number 5, 047,023 awarded to Berg teaches the benefits of an acquisition zone that has a low density and a low basis weight to allow rapid absorption of the liquid. U.S. Patent No. 5,348,547 issued to Payne et al. Teaches a dual layer absorbent system in which an acquisition layer consists of a low density region and a high density region to allow rapid absorption and Subsequent distribution of liquid from a point of discharge. International Patent Application number WO 98/29071 to Molnycke AB discloses an improved acquisition / transport layer having improved tactile characteristics, which allows it to be used directly in contact with the wearer's skin. U.S. Patent No. 5,397,316 issued to LaVon et al. Describes various configurations of polymeric foams, which have been designed to rapidly absorb liquid.

The above-mentioned patents describe specific absorbent compound properties, which result in improved cost performance. In general, the aforementioned patents and publications teach various configurations of absorbent composites to improve the rate of fluid intake. However, the aforementioned patents do not specifically refer to the above-mentioned problems, such as improving runoff / absorption during the life cycle of the absorbent compound.

What is required in the art is an absorbent compound having optimum compound properties. What is also required in the art is an absorbent compound, which exhibits an improved fluid absorption rate, and superior fluid absorption of multiple discharges during the life of the compound, without the problems associated with known absorbent compounds.

SYNTHESIS OF THE INVENTION The present invention is directed to absorbent compounds, which have been developed to refer to the problems described above associated with currently available absorbent compounds and other absorbent compounds described in the literature. The absorbent composites of the present invention have improved compound absorption properties as a result of having a Compound Permeability value at a complete swelling of more than about 100 x 10"8 square centimeters and an absorption rate ratio. Return Flow of Third Insult Fluid Absorption (FIFE) / permeability value of the compound, where the permeability value of the compound varies depending on the intake rate of return flow evaluation of fluid absorption of the third insult. The combination of the properties of the compound is an indication of the ability of the absorbent compound to have an improved fluid absorption rate, and a higher fluid absorption of multiple discharges during the life of the compound. they lose their functioning of fluid absorption during the life of the compound, the compounds The absorbers of the present invention function exceptionally well, exhibiting superior fluid absorption after multiple discharges into the composite.

The present invention is also directed to a method for making absorbent compounds having a compound permeability value at a compound swelling of more than about 100 x 108 square centimeters and an absorption rate evaluation ratio of absorption back flow. of third insult fluid (FIFE) / permeability value of the compound, where the permeability values of the compound vary depending on the rate of absorption of flow return evaluation of fluid absorption of the third insult. The absorbent compounds of the present invention can be made by a variety of processes.

The present invention is further directed to absorbent composites comprising fibrous material, and to its applicability in disposable personal care products. The absorbent composites of the present invention are particularly useful as absorbent components in personal care products such as diapers, women's pads, panty liners, incontinence products, and training underpants.

BRIEF DESCRIPTION OF THE FIGURES Figures 1 a-c are an illustration of the equipment for determining the permeability value of the compound of an absorbent compound.

Figure 2 is an illustration of the equipment for determining the flow assessment or return value of fluid intake (FIFE) of an absorbent composite.

Figure 3 is an illustration of the equipment for determining the absorption / desorption value of an absorbent composite.

DESCRIPTION OF PREFERRED INCORPORATIONS The present invention is directed to absorbent compounds, wherein the absorbent compounds possess the ability to maintain exceptional absorption performance even after multiple discharges into the compound. The present invention achieves these results by approaching the problems of absorption and runoff operation in an unconventional manner. Traditionally, the approach taken to refer to fluid absorption has been to strategically locate relatively large amounts of superabsorbents and / or superabsorbents having a high load capacity in an absorbent composite. The objective was to produce an absorbent compound having an increased capacity to finally provide the compound with improved fluid absorption performance. However, it has been determined that the pursuit of a superior superabsorbent capacity inevitably leads to a limited performance improvement. In particular, this approach results in a decrease in the performance of absorption of the compound during the life cycle of the compound. The present invention has discovered that methods for achieving rapid liquid absorption as well as increased absorption performance over the life of the composite can be achieved with relatively high amounts of superabsorbent materials by concentrating on the permeability of the compound and its relationship to the absorption rate of return flow evaluation of fluid intake of the third insult (FIFE) of the compound.

The absorbent compounds of the present invention desirably possess improved or constant fluid absorption during the life of the compound. The fundamental absorbent property of the permeability of the composite of an absorbent material is a key to rapid absorption. A method for measuring the permeability of the compound is with the compound permeability test, which is described in detail below. This test measures the time required for a fixed volume of liquid to flow through a presaturated compound in the z direction. As shown in Table 1, the preferred properties of the composition of absorbent materials include fibers and / or superabsorbent material, allowing the formation of an absorbent composition having a compound of more than about 150 x 10"8 square centimeters. it was shown in Table 1, all the first five absorbent compounds (samples 1-5) exhibited a high compound permeability (> 150 x 10 ~ 8). However, some combinations of the absorbent composites result in absorbent composites having a permeability of compounds of much less than 150 x 10"8 square centimeters, as shown by samples 6 and 7.

Table 1. Permeability of the Compound for Absorbent Compounds Containing 50% by weight of Fibers and 50% of superabsorbent material Another important feature of the absorption performance of the compound is measured by the fluid absorption return flow (FIFE) evaluation test, which is described in detail below. The fluid absorption return flow evaluation test measures how fast the fluid can flow into a material. Table 2 shows the rates of fluid flow return absorption evaluation of the third insult for a variety of absorbent composites containing 50% by weight of superabsorbent material and 50% by weight of fibers. It can be seen that absorbent composites containing different superabsorbents exhibit different rates of fluid flow return absorption assessment. As shown in Table 2, all of the first five absorbent compounds (samples 1-5) exhibited rapid absorption rates (> 2.75 ml / sec). However, some combinations of the absorbent composites resulted in absorbent composites having a take rate of much less than 2.75 ml / second, as shown by samples 6 and 7.

Table 2. Third Insult Fluid Absorption Return Flow Evaluation Rate for Absorbent Compounds containing 50% by weight of Fibers and 50% by weight of Super Absorbent Material The improved take-up behavior as seen by the return rate evaluation rate of fluid absorption of the third insult can be controlled by the amount of superabsorbent material present in the absorbent composite. Table 3 shows the rate of return flow evaluation of fluid absorption of the third insult for two sets of compounds containing one of two superabsorbent materials (identified as Stockhausen Favor 880 and Dow XUS 40665.07). For each type of superabsorbent material, compounds containing either 30% by weight, 40% by weight, 50% by weight, or 60% by weight of superabsorbent material were prepared and evaluated. All the compounds had a total basis weight of 400 grams per square meter. This resulted in compounds that have a base weight of superabsorbent of 120 grams per square meter, 160 grams per square meter, 200 grams per square meter, or 240 grams per square meter.

Table 3 Fluid Absorption Return Flow Rate of the Third Discharge for Absorbent Compounds with Percent by Weight of Variable Superabsorbent Material Fluid Absorption Return Flow Rate of Third Discharge (ml / sec) As can be seen in Table 3, by changing the amount of superabsorbent material in the composite, the rate of absorption of fluid back flow evaluation of the third insult of the compound changes. In addition, at superabsorbent levels of 40% by weight, 50% by weight and 60% by weight, a compound comprising the Dow XUS 40665.07 superabsorbent material exhibits an absorption rate of return flow evaluation of fluid absorption of the third most desirable and fastest discharge compared to a compound comprising Stockhausen Favor 880 superabsorbent material.

To further demonstrate the impact of the type and amount of the superabsorbent material present in the compound on the compound absorption behavior, Table 4 shows the rate of absorption of fluid return return evaluation of the third discharge for two sets of absorbent compounds containing one of two superabsorbent materials (identified as Stockhausen Favor 880 and Dow XUS 40665.07). However, in these two sets, for each type of superabsorbent material, the compounds having a total compound basis weight of either 200 grams per square meter, 300 grams per square meter, 400 grams per square meter, or of 500 grams per square meter, were prepared and evaluated. All the compounds had 50% by weight of wood pulp fibers and 50% by weight of superabsorbent material. This results in absorbent compounds having a super-absorbent basis weight of 100 grams per square meter, 150 grams per square meter, 200 grams per square meter, or 250 grams per square meter.

Table 4. Fluid Absorption Return Flow Rate of the Third Discharge for Absorbent Compounds with Base Weight of Variable Compound Rate of Evaluation of Return Flow of Fluid Absorption of the Third Discharge (ml / sec) As best seen in Table 4, by changing the basis weight of the compound (and the basis weight of the superabsorbent), the rate of fluid flow return-absorption evaluation rate of the third discharge also changes. In addition, at base weights of superabsorbent 150 grams per square meter, 200 grams per square meter, or 250 grams per square meter, a compound comprising the superabsorbent material Dow XUS 40665.07 exhibits an absorption rate of return flow evaluation of fluid absorption of the third discharge, more desirable and faster compared to a compound comprising Stockhausen Favor 880 superabsorbent material.

As would be expected, the permeability of the composite can also be controlled by the amount of the superabsorbent material present in the absorbent composite. Table 5 shows the permeability of the compound for two sets of compounds containing one of two superabsorbent materials (identified as Stockhausen Favor 880 and Dow XUS 40665.07).

For each type of superabsorbent material, compounds containing either 30% by weight, 40% by weight, 50% by weight or 60% by weight of superabsorbent material were prepared and evaluated. All the compounds had a total basis weight of 400 grams per square meter. This results in compounds having a super-absorbent base weight of 120 grams per square meter, 160 grams per square meter, 200 grams per square meter, or 240 grams per square meter.

Table 5 Permeability of Compound for Absorbent Compounds with Percent by Weight of Supersorbent Material Variable Permeability to Compound (x 10 '8 cm2) As can be seen from Table 5, by changing the amount of the superabsorbent material in the compound, the permeability of the compound changes. In addition, at superabsorbent levels of 30% by weight, 40% by weight, 50% by weight and 60% by weight, a compound comprising Dow XUS 40665.07 superabsorbent material exhibits superior compound permeability as compared to a composite comprising the stockhausen Favor 880 superabsorbent material.

The absorbent composites of the present invention have a compound permeability value at a complete swelling of more than about 100 x 10 ~ 8 square centimeters. Desirably, the absorbent composites of the present invention have a CP value at full swelling of more than about 175 x 10"8 square centimeters.More desirably, the absorbent composites of the present invention have a CP value at full swelling of more than about 190 x 10"s square centimeters. Even more desirably, the absorbent composites of the present invention have a CP value at full swelling of more than about 205 x 10"8 square centimeters, Most desirably, the absorbent composites of the present invention have a CP value at full swelling of more than of about 225 x 10"8 square centimeters. When the absorbent composites of the present invention have a CP value at full swelling of more than about 175 x 10"8 square centimeters, desirably the absorption rate of return flow evaluation of fluid absorption of the third discharge is greater than about 2.0 ml / second More desirably, when the absorbent compounds of the present invention have a CP value at full swelling of more than about 175 x 10 ~ 8 square centimeters, the rate of return flow evaluation of fluid absorption of the third discharge is greater than about 2.50 ml / second, Even more desirably, when the absorbent compounds of the present invention have a CP value at full swelling of more than about 175 x 10 ~ 8 square centimeters, the rate of intake The fluid discharge return flow evaluation of the third discharge is greater than about 2.75 ml / second, more desirably when the Absorbent pads of the present invention have a CP value at full swelling of more than about 175 x 10"8 square centimeters, the rate of fluid flow return absorption evaluation of the third discharge is greater than about 2.75. ml / second. More desirably when the absorbent composites of the present invention have a CP value at full swelling of more than about 175 x 10 ~ 8 square centimeters, the rate of return flow evaluation of discharge absorption is greater than about 3.00 ml / second.

In one embodiment, the absorbent compounds of the present invention have an absorption value ratio of return flow evaluation of third fluid discharge (FIFE) / compound permeability value where the permeability value of the compound varies depending on the return flow evaluation rate of the fluid absorption of the third discharge. Desirably, when the intake rate of the fluid absorption return flow evaluation of the third discharge (IR) of the absorbent compound is greater than 0 ml / second and less than 3.00 milliliter / second, the permeability value of the compound (CP) to a complete swelling of the absorbent compound is given by the following equation: CP > . { 135 - [(35/3) x (3.00 - IR)]} x 10"where the permeability of the compound has the units in square centimeters, for example, when the absorbent compound has an absorption rate (IR) of the fluid absorption return flow (FIFE) evaluation of the third discharge of 3.00 milliliters / second, the permeability value of the compound is desirably equal to or greater than about 135 x IX8 square centimeters Additionally, when the absorbent compound has an absorption rate (IR) of the fluid flow back absorption evaluation of the third discharge of 1.00 ml / second, the CP value is desirably equal to or greater than about 112 x 108 square centimeters.

In yet another embodiment, the absorbent composites of the present invention have an absorption rate (IR) of fluid return evaluation of the third insult greater than 3.00 ml / second and less than about 3/70 ml / second. When the absorption rate (IR) of the fluid absorption return flow evaluation of the third discharge of the absorbent compound falls within this range, desirably the compound permeability value (CP) to the complete swelling of the absorbent compound is given by the following equation.

CP =. { 175 - [(400/7) x (3.70 - IR)]} x 10"8 where the permeability of the compound has units of square centimeters. For example, when the absorbent compound has an absorption rate (IR) of fluid flow return absorption evaluation of the third discharge of 3.50 ml / second, the permeability value of the compound is desirably equal to or greater than about 164 x IX8 square centimeters. In addition, when the absorbent compound has an absorption rate (IR) of back flow evaluation of fluid absorption of the third discharge of 3.20 milliliters / second, the permeability value of the compound is essentially equal to or greater than about 146 x 10"8 square centimeters.

In another embodiment, the absorbent compounds of the present invention have a third discharge fluid return flow (FIFE) / permeability value ratio of the compound represented by the following equations. When the absorption rate (IR) of the fluid absorption return flow evaluation of the third discharge of the absorbent compound is greater than 0 milliliters / second and about 3.00 milliliters / second, desirably, the permeability value of the CP compound to a complete swelling of the absorbent compound is given by the following equation: CP =. { 150 - [(35/3) x (3.00 - IR)]} x 10"8 where the permeability of the compound has units of square centimeters In addition, when the rate of absorption (IR) of evaluation of return flow of fluid absorption of the third discharge of the absorbent compound is greater than 3,000 milliliters / second and of less than about 3.70 milliliters / second, desirably the permeability value of the compound (CP) to a complete swelling of the absorbent compound is given by the following equation: CP =. { 190 - [(400/7) x (3.00 - IR)]} x 10"8 where the permeability of the compound has square centimeters units. Further, when the absorbent compound has an absorption rate (IR) of fluid return evaluation of the third discharge of more than about 3.70 ml / second, the permeability value of the compound is desirably equal to or greater than 190 x 10"8 square centimeters.

In yet another embodiment, the absorbent compounds of the present invention have an absorbent rate ratio relative to the return flow, third discharge fluid (FIFE) / permeability value of the compound represented by the following equations. When the rate of absorption (IR) of the fluid return evaluation of fluid intake of the third discharge of the absorbent compound is greater than 0 ml / second and less than about 3.00 ml / second, desirably the permeability value of the compound (CP) to the complete swelling of the absorbent compound is given by the following equation: CP =. { 165 - [(35/3) x (3.00 - IR)]} x 10 ~ 8 where the permeability of the compound has units in square centimeters. Further, when the absorption rate (IR) of the return flow evaluation of the fluid absorption of the third discharge of the absorbent compound is greater than 3.00 ml / second and less than about 3.70 ml / second, desirably the value permeability of the compound (CP) to a complete swelling of the absorbent compound is given by the following equation: CP > . { 205 - [(400/7) x (3.70 - IR)]} x 10"8 where CP has cm2 units. Further, when the absorbent compound has an absorption rate (IR) of the fluid discharge return flow evaluation of the third discharge of more than about 3.70 ml / second, the permeability value of the compound desirably equal to or greater than of about 205 x 10"8 square centimeters.

The absorbent composites of the present invention may comprise one or more absorbent materials. As used herein, the term "superabsorbent material" refers to an organic or inorganic material soluble in water and swellable in water capable, under the most favorable conditions of absorbing more than about 15 times its weight in an aqueous solution containing 0.9 % by weight of sodium chloride. Organic materials suitable for use as a superabsorbent material of the present invention may include natural materials such as agar, pectin, water and the like; and synthetic materials such as hydrogel polymers. Hydrogel polymers include, but are not limited to, alkali metal salts, polyacrylic acids, polyacrylamides, polyvinyl alcohol, maleic anhydride ethylene copolymers, polyvinyl ethers, hydroxypropyl cellulose, polyvinyl morpholinone; and polymers and copolymers of vinyl sulphonic acid, polyacrylates, polyacrylamides, polyvinyl pyrridine and the like. Other suitable polymers include hydrolyzed acrylonitrile grafted starch, acrylic acid grafted starch, and isobutylene maleic anhydride copolymers and mixtures thereof. The hydrogel polymers are desirably crosslinked to render the material essentially insoluble in water. Cross-linking can, for example, be by radiation or by covalent, ionic, Van der Waals or hydrogen bonding. The superabsorbent materials may be in any form suitable for use in the absorbent composites including the particles, fibers, flakes, spheres, and the like.

Although a wide variety of superabsorbent materials are known, the present invention relates, in one aspect to the suitable selection of one or more superabsorbent materials to allow the solution of absorbent compounds having improved composite properties and disposable absorbent garments containing the same. Superabsorbent materials suitable for use in the absorbent composites of the present invention include any superabsorbent material, which allows the formation of an absorbent compound having a compound permeability value (CP) at a full swell of more than about 100 x. 10"8 square centimeters and an absorption rate ratio of return flow evaluation of third discharge fluid intake (FIFE) / permeability of the compound as described above Desirably, the superabsorbent materials used in the absorbent composites of the present invention comprise superabsorbent materials having a superior gel bed permeability value (GBP) and an absorbency value under load (AUL) at 0.6 pounds per square inch (41,370 dynes / square centimeters) Such superabsorbent materials are described in the application provisional and co-pending patent of the United States of America, Rie No. 60 / 114,432, filed on December 31, 1998 as KC No. 14. 469, entitled "ABSORBENT COMPOSITE THAT COMPRISES SUPERBOROUS MATERIALS" in the name of Yarbrough and others, and assigned to Kimberly-Clark Worldwide, Inc., which is incorporated herein by reference in its entirety.

In one embodiment of the present invention, the absorbent compositions comprise one or more superabsorbent materials in the form of a sodium salt of a crosslinked polyacrylic acid. Such superabsorbent materials include, but are not limited to Stockhausen W-65431 (available from Stockhausen Chemical Company, Inc., of Greensboro, North Carolina); Dow AFA-173-60B, Dow XU 40671.00, Dow XUS 40665.07, and Dow XUS 40667.01 (all available from Dow Chemical Company, of Midland, Michigan).

In addition, of the superabsorbent materials described above, the absorbent composites of the present invention may comprise means for containing the superabsorbent material. Any means capable of containing the superabsorbent materials described above, which means is further capable of being located in a disposable absorbent garment, are suitable for use in the present invention. Many such containment means are known to those with skill in the art. For example, the containment means may comprise a fibrous matrix such as an air-laid or wet-laid fabric of cellulosic fibers, a blown fabric with melting synthetic polymer fibers, a bonded and bonded fabric of synthetic polymer fibers, a coform matrix comprising cellulosic fibers and fibers formed of a synthetic polymeric material, heat-melt fabrics and placed by air of a synthetic polymeric material, open cell foams and the like.

Alternatively, the containment means may comprise two layers of material, which are joined together to form a bag or compartment, more particularly a plurality of bags, which bags contain superabsorbent material. In such a case at least one of the layers must be permeable to water. The second layer of material may be water permeable or water impermeable. The layers of material may be woven or non-woven cloth type, open or closed cell foams, perforated films, elastomeric materials or may be fibrous fabrics of material. When the containment means comprises layer of material, the material must have a sufficiently small or tortuous pore structure in a form sufficient to contain the majority of the superabsorbent material. The containment means may also comprise a laminate of two layers of material between which the superabsorbent material is located and contained. In addition, the containment means may comprise a structure, bearing, such as a polymeric film, which is fixed from the superabsorbent material. The superabsorbent material may be attached to one or both sides of the support structure, which may be water permeable or water impermeable.

Desirably, the absorbent composites of the present invention comprise a superabsorbent material in combination with a fibrous matrix containing one or more types of fibrous materials. Suitable fibrous material includes any fibrous material which allows the formation of an absorbent compound having a compound permeability value (CP) at a full swell of more than about 100 x 10"8 square centimeters and at a rate ratio of absorption absorption evaluation of fluid absorption (fiber) of the third insult / permeability of the compound as described above The fibrous material forming the absorbent composites of the present invention can be selected from a variety of materials including natural fibers , Synthetic fibers and combinations thereof A number of suitable fiber types are described in U.S. Patent No. 5,601,542 assigned to Kimberly-Clark Corporation, which is incorporated herein by reference in its entirety. of the fibers will depend, for example, on the intended end use of the finished absorbent composite. For example, suitable fibrous materials may include, but are not limited to, natural fibers, such as cotton, linen, jute, hemp, wool, wood pulp, etc. Similarly regenerated cellulosic fibers, such as viscose rayon and cupramonium rayon, modified cellulosic fibers such as cellulose acetate or synthetic fibers, such as those derived from polyesters, polyamides, polyacrylics, etc., in combination with each other can similarly be used. Mixtures of one or more of the above mentioned fibers can also be used if desired.

The fibrous materials can be conveniently characterized by their water retention values (WRV). The test method for determining the water retention values of a fiber is described below. For example, thing CR-1654 of Alliance Forest Products, of (Coosa Pines, Al), has a water retention value of about 1.0 - 1.1 g / g; NHB416 from Weyerhaeuser Company (Federal Way, Washington) has a value of about 0.54 g / g; Weyerhaeuser HBAS has a value of about 0.46 g / g; and synthetic fibers such as those made with polypropylene have a water retention value of about zero g / g. High water retention value pulps such as CR 1654 are readily available and are widely used in absorbent products. The water value retention value pulps (of about 0.5 g / g or less) are less widely used in the slurry / superabsorbent pulp mixes due to their limited compatibility with most production technologies. Synthetic fibers such as those made of cellulose acetate, polypropylene, and polyethylene are used in personal care products such as diapers in a limited amount due to their undesirable surface properties. Although their surface properties of these synthetic fibers can be modified by coating them with only one surfactant, other complications such as surfactant washout can occur.

In one embodiment of the present invention, the absorbent composites comprise a mixture of superabsorbent material of fibrous materials, wherein the water retention value of the fibrous material is greater than about 0. 2 g / g. Desirably, the water retention value of the fibrous material is greater than about 0.35 g / g. More desirably, the water retention value of the fibrous material is more than about 0.5 g / g. Even more desirably, the water retention value of the fibrous material is greater than about 0.7 g / g. More desirably, the water retention value of the fibrous material is greater than about 0.9 g / g. In table 6 it contains water retention value data for a variety of fibers.

Table 6. Water Retention Value of Various Fibers * Alliance Forest Products (Coosa Pmes, AL) # Modified Pulp KC ** Weyerhaeuser Company (Federal Way, Washington) *** Removed from a Procter & gamble In an embodiment of the present invention, the relative amount of superabsorbent material of the fibrous material used to produce the absorbent compounds of the present invention may vary depending on the desired properties of the resulting product and the resulting product. Desirably, the amount of superabsorbent material in the absorbent composite is from about 20% by weight to about 100% by weight and the amount of fibrous material is from about 80% to about 0% by weight based on the Total step of the absorbent compound. More desirably, the amount of the superabsorbent material is from about 30% to about 90% and the amount of the fibrous material is from about 70% to about 10% by weight, based on the total weight of the absorbent. More desirably, the amount of the superabsorbent material of the absorbent compound is from about 40% by weight to about 80% by weight and the amount of the fibrous material is from about 60% to about 20% by weight based on the total weight of the absorbent compound.

In a further embodiment of the present invention, the basis weight of the superabsorbent material used to produce the absorbent compounds of the present invention may vary depending on the desired properties, such as the thickness of the total compound and the basis weight, in the resulting product, and the application of the resulting product. For example, absorbent compounds for use in diapers for use in the infant may have a lower basis weight and a lower thickness compared to an absorbent composite for an incontinence device. Desirably, the basis weight of the superabsorbent material in the absorbent composite is greater than about 80 grams per square meter (gsm). More desirably, the superabsorbent basis weight in the absorbent composite is from about 80 grams per square meter to about 800 grams per square meter. More desirably, the basis weight of the superabsorbent material in the absorbent composite is from about 120 grams per square meter to about 200 grams per square meter. More desirably, the basis weight of the superabsorbent material in the absorbent composite is from about 150 grams per square meter to about 600 grams per square meter.

The absorbent compounds of the present invention can be made by any process known to those of ordinary skill in the art. In an embodiment of the present invention, the superabsorbent particles are incorporated into the superabsorbent fibrous substrate. Suitable fibrous substrates include but are not limited to woven and non-woven fabrics. In many embodiments, personal care products in particular, preferred substrates are non-woven fabrics. As used herein, the term "non-woven fabric" refers to a fabric having a structure of individual fibers or filaments randomly arranged in a mat-like shape. Non-woven fabrics can be made from a variety of processes including, but not limited to, air-blowing placement processes, wet-laying processes, hydroentangling processes, basic fiber bonding and carding, and to the spinning of solution. The superabsorbent material can be applied in the form of a solid particle material or a site of a solution. The superabsorbent material may be in any form suitable for use in absorbent compounds including particles, fiber flakes, spheres and the like.

In a further embodiment of the present invention, the superabsorbent material and the fibrous material are mixed simultaneously to mix an absorbent compound. Desirably, the composite materials with mixed by an air forming process known to those with ordinary skill in the art. The air formation of the mixture of fibers and superabsorbent material is intended to encompass both the situation where the preformed fibers are placed by air with the superabsorbent material, as well as the situation in which the superabsorbent material is mixed with the fibers at the be the fibers formed, such as through a process are blown with fusion.

It should be noted that the superabsorbent material can be evenly distributed from the absorbent compound or it can be evenly distributed within the absorbent composition. The superabsorbent material can be distributed through the complete superabsorbent compound or it can be distributed within a small localized area within an absorbent composite.

The absorbent composites of the present invention can be formed from a single layer of superabsorbent or multiple layers of superabsorbent material. In the case of multiple layers the layers may be placed in a side-by-side or surface-to-surface relationship and all or a portion of the layers may be attached to the adjacent layers. For example, in those cases where the absorbent composite includes multiple layers, the entire thickness of the absorbent composite may contain one or more superabsorbent materials or each individual layer may separately contain some superabsorbent material or not contain superabsorbent materials. Each individual layer may contain different superabsorbent materials of an adjacent layer. For example, in one embodiment of the present invention, a multi-layer absorbent composite comprises a more superior absorbent layer (user side) containing a type of superabsorbent material, and a second layer containing a second, different type of superabsorbent material.

The absorbent compounds according to the present invention are suitable for absorbing many fluids including body fluids such as urine, menstrual fluids, blood, and are suitable for use in garments such as diapers, adult incontinence products, pads for the bed, and the like; catameneal devices, such as sanitary napkins, plugs and the like; and in other absorbent products such as bibs, cleansing cloths, wound dressings, food packaging and the like. Therefore, in another aspect, the present invention relates to a disposable absorbent garment comprising an absorbent compound as described above. A wide variety of absorbent garments are known as those skilled in the art. The absorbent composites of the present invention can be incorporated into such known absorbent garments. Exemplary absorbent garments are generally described in U.S. Patent No. 4,710,187 issued December 1, 1987 to Boland et al .; 4,762,521 issued on August 9, 1988 to Roessler et al .; 4,770,656 granted on September 13, 1988 to Proxmire and others; 4,798,603 granted on January 17, 1989 to Meyer et al .; whose references are incorporated here by this mention.

As a general rule, absorbent disposable garments according to the present invention comprise a body-side liner adapted to contact the wearer's skin, an outer covering superimposed in a front relation with the liner and an absorbent composite, such as those described above, opposites on said outer cover and located between the side-to-body liner and the outer cover.

Those skilled in the art will readily understand that the absorbent compounds of the present invention can be advantageously employed in the preparation of a wide variety of products, including but not limited to absorbent personal care products designed to come into contact with body fluids. . Such products may only comprise a single layer of the absorbent compound and may comprise a combination of elements as described above. While the absorbent composites of the present invention are particularly suitable for personal care products, the absorbent composites can be advantageously employed in a wide variety of consumer products.

TEST METHODS The test methods to determine the water retention value (WRV) of the fibers and the compound permeability test, the test of evaluation of the return flow of fluid absorption, and the absorption / desorption test of the compounds Absorbents are described below.

Water Retention Value Test (WRV) The water retention value test (WRV) determines the water retention of a fiber sample. This test, a sample of fibers (0.5 g) was dispersed 100 ml of deionized water and soaked overnight to allow equilibration. Then, the solution was poured into a cylinder with the inside diameter of 1.9 inches (4.83 centimeters). The bottom of this cylinder was covered with a grid of 100 meshes so that excess water could be drained out of the cylinder. The cylinder is then placed in a normal centrifuge and rotated at l.OOg for 20 minutes. The weight of the pulp is then weighed (Wl), dried at 105 ° C for two hours, and weighed again (W2). The water retention value is calculated as (Wl-W2) / W2 and was given in units of g / g.

Compound Permeability Test The permeability test of the compound determines the permeability of the compound in square centimeters by calculating the time for a fluid to flow through a compound. As shown in Figures IA and IB, the permeability tester consists of 2 concentric cylinders of polycarbonate or Plexiglas, where 1 fits within the other with very little separation, but still slides freely. The inner cylinder 110 has an outer diameter of 6.9 centimeters and an inner diameter of 5.10 centimeters. The outer cylinder / base assembly and stopper has a metal grid 112, on which the test material was placed for examination. This grid is desirably a type 104 stainless steel grid with an orifice diameter of 0.156 inches (0.40 centimeters) and 63% open area, 20 gauge, and 3/16 inches (0.48 centimeters) center-to-center spacing. The cylinder 111 of the base and plug assembly has an inner diameter of 7.0 centimeters and an outer diameter of 7.5 centimeters. A ruler 113 is on the outer side of the outer cylinder 111 with height marks of 3 5/8 inches (9.21 centimeters) and an inch 1/8 inches (2.86 centimeters) from the bottom of the grid 112.

An absorbent composite of the superabsorbent material and of the fluff, or of the fluff itself, is formed by air on the tissue at a desired basis weight and density. This compound 300 is cut by matrix to a desired size, desirably a circle of 6.83 centimeters (2.69 inches) in diameter is used. As shown in Figure 1, the compound is placed on a plate 101 of approximately the same size (diameter) as the compound 100. This prevents swelling in the radial direction. The sample is saturated using a 0.9% aqueous NaCl solution (WV). A cover 102 is placed on the plate and allowed to settle for 30 minutes until equilibrium. A solution can be added, if necessary, to completely saturate the sample. One will generally know when the compound is completely saturated when an excess of liquid exits inside the plate 101. After a total of 30 minutes, of the compound 100 and a plate 101 they are placed head on an absorbent medium such as a paper towel to remove the interstitial fluid. This is done by placing the paper towel on the plate and the compound, and while the plate and towel are stopped, flip it over, this puts the compound in direct contact with the towel. No pressure is applied during this process.

After the drying process, a wet volume thickness of the sample was taken by placing the sample under a thickness gauge with an acrylic plate or similar, which applies a pressure of approximately 0.5 pounds per square inch (3,440 dynes) / cm2). The compound is then placed on the inner cylinder 110 and the outer cylinder (permeability tester) 115 is turned head on the inner cylinder with the compound. The complete apparatus, which now contains the test compound and the inner cylinder, is flipped again for the test. This ensures that the composite rests neatly with the least amount of handling on the grid 112 at the bottom of the test apparatus 115. The test fluid is poured into the inner cylinder at the top of the composite. The fluid must be above the top mark on the array (at least one inch (2.54 centimeters)) before starting the test. To start the test, the plug 114 is removed from the bottom of the permeability apparatus 115 and the timing is started when the fluid front reaches the upper mark on the ruler (3 5/8 inches (9.21 centimeters) above the grid) and the stopwatch stops when the front fluid reaches the lower mark on the ruler (1 1/8 inches (2.86 centimeters) above the grid). The time in seconds is recorded.

The permeability (K) in square centimeters is calculated as follows: K =. { [ln (hi ha) * Mu) / (g * Rho)] * WB / t} where K = compound permeability (square centimeters); hx = height of the top marker (centimeters) [normally 9.21 centimeters]; h2 = height of the lower marker (centimeters) [normally 2.86 centimeters]; Mu = viscosity of the liquid (poises) [normally 0.01 poise]; Rho = density of the liquid (gm / cm3) [normally 1.0 gm / cm3]; WB = wet volume of the compound (cm); t = time for the liquid to move from hx to h2 while flowing through the compound (second) .

Fluid Absorption Return Flow Evaluation Test The fluid function return flow (FIFE) evaluation test determines the amount of time required for an absorbent compound to absorb a pre-set amount of fluid. A suitable apparatus for carrying out the fluid absorption back flow evaluation test is shown in Figure 2.

A superabsorbent and lint compound, or lint is only formed by air on a type of tissue at a desired basis weight and density. The composite is cut to the desired size, in this case, the compound 200 is cut to a square of 5 inches (12.70 centimeters). Compound 200 is placed under test pad 201 for evaluating the return flow of fluid 201. The test pad is a flexible conformable silicon pad that is 10 inches (25.4 centimeters) x 20 inches (50.8 centimeters) . The silicon pad using Dow Corning 227 unprimed silica dielectric gel and wrapping it in a shrinkable plastic wrap. This pad is made thick enough to produce a pressure thickness of approximately 0.03 pounds per square inch (2,069 dynes / square centimeters). The pad contains a Plexiglas 202 cylinder with an inside diameter of 5.1 centimeters and an outside diameter of 6.4 centimeters and the bottom of the cylinder has a 203 lid with a 1 inch (2.54 cm) circular hole in the center where the fluid Test is placed in direct contact with compound 200. The center of the cylinder is placed 6.75 inches (17.15 centimeters) below the top edge of the silicon pad 201 and is centered from side to side (5 inches (12.70 centimeters from the edge An automated controller 205 can be connected to the 206 and 207 electrodes that self-initiate the test with the input of the test fluid.This can eliminate the variability of the tester.The test fluid is desirably a 0.9% solution (w / v of NaCl.

The test is run by placing the compound 200 under the silicone test pad 201. The desired amount of fluid is dispersed from a positive displacement pump. The amount of fluid in this case is calculated according to the composition of the compound. For example, the amount of fluid for a compound of 400 grams per square meter of a size of 5 square inches (12.60 centimeters) consisting of 50% superabsorbent and 50% fluff is calculated by assuming that the superabsorbent capacity is 30 g / g and the capacity of the flux is 6 g / g. The total amount of the compound's capacity in grams is calculated and 25% of this amount is a discharge. The fluid is supplied at a rate of approximately 10 ml / second. The time in seconds for the fluid to drain cylinder 202 is recorded.

After a wait of 15 minutes, a second download is made and after another 15 minutes of waiting, the third final download is made. The absorption rate of fluid return absorption evaluation for each discharge was determined by directing the discharge amount in milliliters for the time necessary for the fluid to drain from cylinder 202 in seconds. If during the test, the fluid runoff occurs from the top, bottom or sides of the compound, the amount of drained fluid must be measured. In this case, the absorption rate of return flow evolution of fluid absorption for each insult or discharge was determined by subtracting the amount of fluid drained from the amount of discharge fluid and then dividing this amount by time so that the fluid drains from cylinder 202 in seconds.

Absorption / Desorption Test The absorption / desorption test measures the absorption and desorption capacity of a material or compound. A suitable apparatus for carrying out the absorption / desorption test is shown in Figure 3.

A compound may consist of superabsorbent material and erases or deletes only. In this case, the compounds consisting of superabsorbent wood and lint were formed by air on a tissue at a desired basis weight and density. The composite is then cut to the desired size, in this case, the composite is cut to 2.5 inches (6.35 centimeters) by 6 inches (15.24 centimeters). The dry weight of compound 301 to be tested is recorded. The test compound 301 was placed on a piece of polyethylene film 302 which is the exact size of the test compound 301 and was centered on a Plexiglas cradle 303 so that the length of the compound (15.24 centimeters) is perpendicular to the groove. 304 at the bottom of the cradle 303. The cradle 303 has a width of 33 centimeters. The ends 305 of the cradle 303 are locked at a height of 19 centimeters to form an interior distance of 30.5 centimeters and an angle between the upper arms of 60 degrees between the upper arms 306 of the cradle 303. The cradle 303 has a groove of a width of 6.5 millimeters 304 at the lowest point running to the length of the cradle 303. The cradle 304 allows the run-off of the test compound 301 to enter the tray 307. The amount of runoff is recorded by a balance 308 that It can be read as close as 0.01 grams. A pre-set amount of liquid is delivered to the center of the test compound 301 at a desired rate. In this case the amount is 100 milliliters at a rate of 15 milliliters / second and a half inch (1.27 centimeters) above the sample. The amount of runoff is recorded.

The test compound 301 is removed immediately from the 303 cradle and placed on a 2.5 inch (6.35 centimeter) by 6 inch (15.24 centimeter) superabsorbent / dry pulp desorption pad having a density of about 0.20 grams / cubic centimeters in a horizontal position under a pressure of 0.05 pounds per square inch for 15 minutes. The superabsorbent material is desirably Favor 880, available from Stockhausen Inc. (of Greensboro, North Carolina). The pulp is desirably Coosa 1654, available from Alliance Forest Products (of Coosa Pines, AL). This pressure was applied by using a Plexiglas plate. After 15 minutes, the weight of the desorption pad was recorded and the test compound 301 was placed back in the cradle 303 and a second discharge of 100 milliliters was made. After the runoff amount was recorded, the test compound 301 is again placed on a preweighed weight desorption pad under a load of 0.05 pounds per square inch. (dynes / square centimeters) for 15 minutes. After 15 minutes, a weight of the desorption pad was recorded.

The compound 301 is placed back in the cradle 303 for a third discharge. The runoff amount is recorded and the test compound 301 was placed on a preweighed desorption pad and dried under a pressure of 0.05 pounds per square inch for 15 minutes. The amount of fluid absorbed in g / g for each discharge was calculated by subtracting runoff from 100 milliliters and dividing by dry weight of test compound 301. A particularly useful measure of a compound's ability to exhibit fluid absorption The superior of multiple discharges during the life of the compound is that of dividing the absorption value of the third insult by the absorption value of the first insult.

The present invention is further illustrated by the following Examples, which should not be considered in any way as imposing limitations on the scope itself. On the contrary, it should be clearly understood that several other incorporations, modifications, and equivalents thereof may be resorted to which, after reading the description given herein, may suggest themselves to those with a skill in art without departing from the spirit. of the present invention and / or the scope of the appended claims.

EXAMPLE 1 Absorbent Compound Test for Compound Permeability, Third Rate of Fluid Absorption Return Flow Evaluation, and Third / First Absorption / Disbarring Collection Absorbent composites were prepared and evaluated for one or more of the following Compound permeability at full swelling, third rate of return flow evaluation of fluid absorption, and third / first collection of absorption / desorption. Each compound was formed from a superabsorbent material, combined with fluff pulp fibers (from Coosa River CR-1654, available from Alliance Forest Products (Cossa Pines, AL).) The materials were formed into fabrics using an air-forming equipment. The percent by weight of the superabsorbent material and the basis weight of the superabsorbent material were varied as shown in Table 7.

Table 7. Nonwoven Absorbent Compounds of Super-absorbent Material and Wood Pulp Fibers The compounds identified as samples 1 14 and comparative examples C-2, C-6 to C-7, and C-10 to C-15 were evaluated for one or more of the following: compound permeability, third rate of intake for evaluation of the return flow of fluid absorption, and third / first collection of absorption / desorption as described above. The results of these tests are shown in Table 8.

Table 8. Test for Compound Permeability, Third Rate of Collection of Fluid Absorption Return Flow Evaluation, and Third / First Absorption / Desorption Collection As can be seen from the above-mentioned data, absorbent composites having improved take-up operation can be formed.

The examples described above are preferred embodiments and are not intended to limit the scope of the present invention in any way. Various modifications and other embodiments and uses of the superabsorbent polymers disclosed to those of ordinary skill in the art are also considered to be within the scope of the present invention.

Claims (41)

R E I V I N D I C A C I O N S

1. An absorbent composition comprising about 20 weight percent to 100 weight percent, based on the total weight of the compound, of superabsorbent material; wherein the absorbent compound has a compound permeability value (CP) at full swelling and a rate of fluid return evaluation of fluid absorption of the third discharge (FIFE); and wherein the permeability value of the compound and the absorption rate value satisfy the following conditions: When the absorption rate value of the absorbent compound is greater than 0 ml / second and less than about 3.00 ml / second, the value of permeability to the compound is given for the following equation: CP =. { 135 - [(35/3) x (3.00 - IR)]} x 10"8 when the absorption rate value of the absorbent compound is greater than about 3.00 ml / second and less than about 3.70 ml / second, the permeability value of the compound is given by the following equation: CP > . { 175 - [(400/7) x (3.70 - IR)]} x 10"8, and wherein the absorption rate value of the absorbent compound is greater than about 3.70 ml / second, the permeability value of the compound is greater than or equal to 175 x 10"8, where the permeability of the compound has units of square centimeters.

2. The absorbent compound as claimed in clause 1 characterized in that the permeability value of the compound and the value of the absorbency index satisfy the following conditions: when the absorbency rate value of the absorbent compound is greater than 0 ml / second and less than about 3.00 ml / second, the permeability value of the compound is given by the following equation: CP =. { 150 - [(35/3) x (3.00 - IR)]} x 10"8 when the absorption rate value of the absorbent compound is greater than about 3.00 ml / second and less than about 3.70 ml / second, the permeability value of the compound is given by the following equation: CP =. { 190 - [(400/7) x (3.70 - IR)]} x 10"8, - and when the absorption rate value of the absorbent compound is greater than about 3.70 ml / second, the permeability value of the composite is greater than or equal to 190 x 10"8, where the permeability of the composite has units of square centimeters .

3. The absorbent compound as claimed in clause 2, characterized in that the permeability value of the compound and the value of the absorbency rate satisfy the following conditions: when the absorbency rate value of the absorbent compound is greater than 0 ml / second and less than about 3.00 ml / second, the permeability value of the compound is given by the following equation: CP > . { 165 - [(35/3) x (3.00 - IR)]} x 10"8 when the absorbency rate value of the absorbent compound is greater than about 3.00 ml / second and less than about 3.70 ml / second, the permeability value of the compound is given by the following equation: CP > . { 205 - [(400/7) x (3.70 - IR)]} x 10"8; when the value of the absorption rate of the absorbent compound is greater than about 3.70 ml / second, the permeability value of the composite is greater than or equal to 205 x 10"8, where the permeability of the composite has units of square centimeters.

4. The absorbent compound as claimed in clause 1 characterized in that the absorbent compound has a permeability value of the compound at full swelling of more than about 175 x 10"8 square centimeters.

5. The absorbent compound as claimed in clause 1 characterized in that the absorbent compound has a permeability value of the compound at full swelling of more than about 190 x 10"8 square centimeters.

6. The absorbent compound as claimed in clause 1 characterized in that the absorbent compound has a permeability value of the compound at full swelling of more than about 205 x 10"8 square centimeters.

7. The absorbent compound as claimed in clause 1 characterized in that the absorbent compound has a permeability value of the compound at full swelling of more than about 225 x 10"8 square centimeters.

8. The absorbent compound as claimed in clause 1 characterized in that the absorbent compound has a rate of return evaluation evaluation of fluid absorption of the third discharge of about 2.00 ml / second and a permeability value of the compound to full swelling of more than about 125 x 10"8 square centimeters.

9. The absorbent compound as claimed in clause 1 characterized in that the absorbent compound has a rate of return evaluation of fluid absorption of the third discharge of more than about 0.1 ml / second and a permeability value from the compound to full swelling of more than about 175 x 10"8 square centimeters.

10. The absorbent compound as claimed in clause 1 characterized in that the absorbent compound has a rate of return evaluation evaluation of fluid absorption of the third discharge of about 2.50 ml / second and a permeability value of the compound to full swelling of more than about 175 x 10"8 square centimeters.

11. The absorbent compound as claimed in clause 1 characterized in that the absorbent compound has a rate of return evaluation evaluation of fluid absorption of the third discharge of more than about 3.00 ml / second and a permeability value from the compound to full swelling of more than about 175 x 10"8 square centimeters.

12. The absorbent compound as claimed in clause 1 characterized in that the absorbent composite further comprises from about 80 to about 0 percent by weight of fibers.

13. The absorbent composite as claimed in clause 12 characterized in that the absorbent composite comprises from about 30 to about 90 percent by weight of superabsorbent material and from about 70 to about 10 percent by weight of fibers .

14. The absorbent compound as claimed in clause 13 characterized in that the absorbent compound comprises from about 40 to about 80 weight percent superabsorbent material and from about 60 to about 20 weight percent fiber .

15. The absorbent compound as claimed in clause 12 characterized in that the fibers have a water retention value (WRV) greater than about 0.2 g / g.

16. The absorbent compound as claimed in clause 15 characterized in that the fibers have a water retention value (WRV) greater than about 0.5 g / g.

17. The absorbent compound as claimed in clause 16 characterized in that the fibers have a water retention value (WRV) greater than about 0.7 g / g.

18. The absorbent compound as claimed in clause 17 characterized in that the fibers have a water retention value (WRV) of greater than about 0.9 g / g.

19. The absorbent compound as claimed in clause 1 characterized in that the absorbent compound has a basis weight of the superabsorbent material of more than about 80 grams per square meter.

20. The absorbent compound as claimed in clause 19 characterized in that the absorbent compound has a basis weight of the superabsorbent material of from about 80 grams per square meter to about 800 grams per square meter.

21. The absorbent compound as claimed in clause 20 characterized in that the absorbent compound has a basis weight of the superabsorbent material of from about 120 grams per square meter to about 700 grams per square meter.

22. The absorbent compound as claimed in clause 21 characterized in that the absorbent compound has a basis weight of the superabsorbent material of from about 150 grams per square meter to about 600 grams per square meter.

23. The absorbent compound as claimed in clause 1 characterized in that the superabsorbent material comprises sodium polyacrylate.

24. An absorbent compound comprising from about 20 to about 100 percent by weight of superabsorbent material and from about 80 to about 0 percent by weight of fibers, wherein the compound has a permeability value of the compound ( CP) at full swelling greater than or equal to 175 x 10"8 square centimeters.

25. The absorbent compound as claimed in clause 24 characterized in that the fibers have a water retention value (WRV) greater than about 0.2 g / g.

26. The absorbent compound as claimed in clause 25 characterized in that the fibers have a water retention value (WRV) greater than about 0.5 g / g.

27. The absorbent compound as claimed in clause 26 characterized in that the fibers have a water retention value (WRV) of greater than about 0.7 g / g.

28. The absorbent compound as claimed in clause 27 characterized in that the fibers have a water retention value (WRV) greater than about 0.9 g / g.

29. A method for making an absorbent compound, said method comprises: forming an absorbent composite comprising from about 20 weight percent to 100 weight percent, based on the total weight of the compound, of the superabsorbent material; wherein the absorbent compound has a permeability value of the compound (CP) at full swelling and an absorption rate (IR) for evaluation of the return flow of fluid absorption of the third insult (FIFE); and wherein the permeability value of the compound and the absorption rate value satisfy the following conditions: When the absorption rate value of the absorbent compound is greater than 0 ml / second and less than about 3.00 ml / second, the value of permeability to the compound is given for the following equation: CP =. { 135 - [(35/3) x (3.00 - IR)]} x 10"8 when the absorption rate value of the absorbent compound is greater than about 3.00 ml / second and less than about 3.70 ml / second, the permeability value of the compound is given by the following equation: CP =. { 175 - [(400/7) x (3.70 - IR)]} x 10 -8; Y when the absorption rate value of the absorbent compound is greater than about 3.70 ml / second, the permeability value of the composite is greater than or equal to 175 x IX8, where the permeability to the composite has units of square centimeters.

30. The method as claimed in clause 29, characterized in that the permeability value of the compound and the absorption rate value satisfy the following conditions: when the absorption rate value of the absorbent compound is greater than 0 ml / second and less than about 3.00 ml / second, the permeability value of the compound is given by the following equation: CP > . { 150 - [(35/3) x (3.00 - IR)]} x 10"8 when the absorption rate value of the absorbent compound is greater than about 3.00 ml / second and less than about 3.70 ml / second, the permeability value of the compound is given by the following equation: CP > . { 190 - [(400/7) x (3.70 - IR)]} x 10"8; when the absorption rate value of the absorbent compound is greater than about 3.70 ml / second, the permeability value of the composite is greater than or equal to 190 x 10"8, where the permeability of the composite has units of square centimeters .

31. The method as claimed in clause 30, characterized in that the permeability value of the compound and the absorption rate value satisfy the following conditions: when the absorption rate value of the absorbent compound is greater than 0 ml / second and less than about 3.00 ml / second, the permeability value of the compound is given by the following equation: CP =. { 165 - [(35/3) x (3.00 - IR)]} x 10 ~ 8 when the absorption rate value of the absorbent compound is greater than about 3.00 ml / second and less than about 3.70 ml / second, the permeability value of the compound is given by the following equation: CP =. { 205 - [(400/7) x (3.70 - IR)]} x 10"8; when the value of the absorption rate of the absorbent compound is greater than about 3.70 ml / second, the permeability value of the compound is greater than or equal to 205 x 10X where the permeability of the composite has units of square centimeters.

32. The method as claimed in clause 29 characterized in that the absorbent compound has a permeability value of the compound at full swelling of more than about 175 x 10"8 square centimeters.

33. The method as claimed in clause 29 characterized in that the absorbent compound is formed by an air forming step.

34. The method as claimed in clause 29 characterized in that the absorbent composite further comprises from about 80 to about 0 percent by weight of fibers.

35. The method as claimed in clause 29 characterized in that the absorbent compound has a basis weight of superabsorbent material of more than about 80 grams per square meter.

36. The method as claimed in clause 35 characterized in that the absorbent compound has a basis weight of superabsorbent material of from about 80 grams per square meter to about 800 grams per square meter.

37. The method as claimed in clause 29 characterized in that the superabsorbent material comprises a sodium polyacrylate.

38. A disposable garment comprising the absorbent compound as claimed in clause 1.

39. A disposable garment comprising at least one absorbent compound, wherein the at least one absorbent compound comprises about 20 weight percent to 100 weight percent, based on the total weight of the composite, of the superabsorbent material; wherein the absorbent compound has a permeability value of the compound (CP) at full swelling and an absorption rate (IR) of evaluation of the return flow of fluid absorption (FIFE) of the third discharge; and wherein the permeability value of the compound and the absorption rate value satisfy the following conditions: when the absorption rate value of the absorbent compound is greater than 0 ml / second and less than about 3.00 ml / second, the permeability value of the compound is given by the following equation: CP =. { 135 - [(35/3) x (3.00 - IR)]} x 10"8 when the absorption rate value of the absorbent compound is greater than about 3.00 ml / second and less than about 3.70 ml / second, the permeability value of the compound is given by the following equation: CP > . { 175 - [(400/7) x (3.70 - IR)]} x 10"8; when the absorption rate value of the absorbent compound is greater than about 3.70 ml / second, the permeability value of the composite is greater than or equal to 175 x 10"8, where the permeability of the composite has units of square centimeters.

40. The disposable garment as claimed in clause 39, characterized in that the permeability value of the compound and the absorption rate value satisfy the following conditions: when the absorption rate value of the absorbent compound is greater than 0 ml / second and less than about 3.00 ml / second, the permeability value of the compound is given by the following equation: CP =. { 150 - [(35/3) x (3.00 - IR)]} x 10"8 when the absorption rate value of the absorbent compound is greater than about 3.00 ml / second and less than about 3.70 ml / second, the permeability value of the compound is given by the following equation: CP =. { 190 - [(400/7) x (3.70 - IR)]} x 10"8, and when the absorption rate value of the absorbent compound is greater than about 3.70 ml / second, the permeability value of the compound is greater than or equal to 190 xl ?X where the permeability of the compound has units of square centimeters.

41. The disposable garment as claimed in clause 40 characterized in that the permeability value of the compound and the absorption rate value satisfy the following conditions: when the absorption rate value of the absorbent compound is greater than 0 ml / second and less than about 3.00 ml / second, the permeability value of the compound is given by the following equation: CP =. { 165 - [(35/3) x (3.00 - IR)]} x 10"8 when the absorption rate value of the absorbent compound is greater than about 3.00 ml / second and less than about 3.70 ml / second, the permeability value of the compound is given by the following equation: CP =. { 205 - [(400/7) x (3.70 - IR)]} x 10"and when the value of the absorption rate of the absorbent compound is greater than about 3.70 ml / second, the permeability value of the composite is greater than or equal to 205 x l? X where the permeability of the composite has units of square centimeters. SUMMARY The present invention is directed to absorbent compounds having improved absorption properties. The absorbent compounds of the present invention have a permeability value of the compound (CP) at a complete swelling of more than about 100 x 10"8 square centimeters In addition, the absorbent compounds of the present invention have an absorption absorption ratio fluid return flow (FIFE) of the third discharge / permeability of the compound, which results in improved absorption properties The present invention is also directed to a method for making absorbent compounds having increased absorption properties. present invention is further directed to absorbent compounds and their application in disposable personal care products. * ¡¡¡¡¡¡¡¡¡¡¡¡¡