MXPA99007695A - Mixed-bed ion-exchange hydrogel-forming polymer compositions and absorbent members comprising relatively high concentrations of these compositions - Google Patents

Abstract

Disclosed are compositions comprising at least one cationic ion-exchange hydrogel-forming polymer and at least one anionic ion-exchange hydrogel-forming polymer, wherein the composition exhibits improved absorbency characteristics relative to comparable mixtures of the hydrogel-forming polymers in their neutralized state. Also disclosed are mixed-bed ion-exhange compositions having improved Performance Under Pressure values relative to prior mixed-bed compositions, which, e.g., alleviate detrimental gel blocking incurred with these prior systems. Also disclosed are absorbent members useful in the containment of body fluids such as urine, that have at least one region comprising a mixed-bed ion-exchange hydrogel-forming absorbent polymer composition in a concentration of from about 60 to 100%by weight.

Description

POLYMER COMPOSITIONS HYDROGEL FORMER OF EXCHANGE OF ION OF MIXED BED AND ABSORBING MEMBERS COMPRISING RELATIVELY HIGH CONCENTRATIONS OF THESE COMPOSITIONS , FIELD OF THE INVENTION * _ The present application relates to absorbent members for absorbing bodily fluids such as urine and menses. This request, in particular, is made with the polymeric polymer of the ionic exchange, the mixed stratum, and members. absorbers having at least one region comprising a relatively high concentration of these compositions. - i BACKGROUND OF THE INVENTION i. ^ 1 D The development of highly absorbent members to be used as diapers - disposable, pads and trusses a. The importance of such products as sanitary napkins is the subject of substantial commercial interest. A highly desired feature for these products is thinness. For example, 1 f .20 diapers thinner or less bulky when worn, fit better under clothing, and are less noticeable. These are also more compact within the package, making the combs easier to carry and store by the consumer. Packaging compaction also results in reduced distribution costs by the manufacturer and the distributor including less shelf space required in the warehouse per unit of X 25 diaper.

The ability to provide thinner absorbent articles such as diapers has been contingent on the ability to develop relatively thin absorbent cores or structures that can acquire and store large quantities of discharged body fluids, particularly urine. In this regard, the use of certain absorbent polymers often referred to as "hydrogels", "superabsorbents" or "hydrocolloid" material, has been particularly important. See, for example, % patent of the United States No. 3,699,103 (Harper et al.), issued June 13, 1972; and U.S. Patent No. 3,770,731 (Harmon), issued June 20, 1972, disclosing the use of these absorbent polymers (hereinafter "polymers"). .0 hydrogel-forming absorbers "), in absorbent articles In reality, the development of the thinnest diapers has been the direct consequence of the thinner absorbent cores that take advantage of the capacity of these hydrogel-forming absorbent polymers. to absorb large amounts of discharged body fluids, typically when used in combination with a fibrous matrix. ^ 15 See, for example, U.S. Patent No. 4,673,402 (Weisman et al.), *. issued on June 16, 1987 and United States Patent No. 4,935,022 (Lash et al. «4 oti os), issued on June 19, 1990, disclosing double-layer core structures comprising a fibrous matrix and useful hydrogel-forming absorbent polymers a. in making diapers thin, compact, not bulky. These hydrogel-forming absorbent polymers are often made by initially polymerizing unsaturated carboxylic acids or derivatives thereof, such as acrylic acid, alkali metal (eg, sodium and / or potassium), or ammonium salts of acrylic acid, alkyl acrylates and the like. These polymers are insoluble in water, still able to swell in water, slightly crosslinking the chains , 25 of the polymer containing carboxyl groups with conventional di or polyfunctional monomer materials such as N, N'-methylenebisacrylamide, trimethylol propane triacrylate or triallyl amine. These slightly cross-linked absorbent polymers still comprise a multiplicity of anionic (charged) carboxyl groups attached to the polymer structure. These charged carboxy groups are what allow the polymer to absorb the body fluids are those that allow the polymer to absorb the body fluids as a result of the osmotic forces forming hydrogels in this way. These hydrogel-forming absorbent polymers are also often made by initially polymerizing unsaturated amines or derivatives thereof, such as diallyldimethylammonium chloride, N, N-dimethylaminoethyl methacrylate, HCl, metacylamido-propyltrimethylammonium hydroxide and the like. These polymers are made insoluble to water, still capable of swelling in water, by lightly crosslinking the polymer chains with conventional di or polyfunctional monomer materials, such as N, N'-methylenebisacrylamide, trimethylol propane triacrylate or triallyl amine. These slightly crosslinked abosorbent polymers still comprise a multiplicity of cationic (charged) amine groups attached to the polymer structure. It is these charged amine groups that allow the polymer to absorb body fluids as the result of osmotic forces, thus forming hydrogeyes. The degree of crosslinking determines not only the insolubility in water of these hydrogel-forming absorbent polymers, but is also an important factor in establishing two other characteristics of these polymers: their absorbent capacity and the gel strength. The absorbent capacity or "gel volume" is a measure of the amount of water or body fluid that a given amount of hydrogel-forming polymer will absorb. The gel strength is related to the tendency of the hydrogel formed from these polymers to deform "or flow" under some applied tension. The hydrogel-forming absorbent polymers useful as absorbers within the absorbent structures and articles such as disposable diapers, need to have the gel volume suitably high as well as the adequately high gel strength. The gel volume needs to be high enough to allow the hydrogel-forming polymer to absorb significant amounts of the aqueous body fluids encountered during the use of the absorbent article. The gel strength needs to be such that the formed hydrogel does not deform and fill to an acceptable degree the hollow capillary spaces within the absorbent structure or the article, thus inhibiting the absorbent capacity of the structure / article as well as the fluid distribution in the entire structure / article. See, for example, U.S. Patent No. 4,654,039 (Brandt et al.), Issued March 31, 1987 (re- issued 9 on April 19, 1988 as a United States patent re- 32,649) and U.S. Patent No. 4,834,735, issued May 30, 1989. These hydrogel-forming polymers are typically lightly crosslinked polyelectrolytes that swell in aqueous electrolytic solutions primarily i * as a result of an osmotic driving force. The osmotic force of * 15 conduction to inflate the hydrogel-forming polymer, results primarily from the polyelectrolyte counterions that dissociate from the polyelectrolyte but are maintained within the swollen polymer due to electroneutrality considerations. The hydrogel-forming polymer comprising weak acid or weak base polyelectrolytes (e.g., carboxylic acid or mono-di-triamine functional groups) in its unneutralized forms are only lightly dissociated in urine solutions. These weak-acid or weak-base hydrogel-forming polymers must be at least partially neutralized with a base or acid, respectively in order to generate substantial concentrations of dissociated counterions. Without neutralization to, for example -70%, these hydrogel-forming polymers of weak acid or weak base do not swell to their maximum potential absorbent capacity or gel volume. In contrast, the absorbent capacity of hydrogel-forming polymers that comprise # strong acid or strong base functional groups (eg, sulphonic acid or quaternary ammonium hydroxide), are much less sensitive to their degree of neutralization. However, the use of these strong acid or strong base hydrogel forming polymers in their non-neutralized forms has the potential to divert the pH t, 5 of the urine solution to unacceptably low or high values, respectively. Even after neutralization, the osmotic conduction forces to swell and thus in the absorbent capacity or gel volume of the polyelectrolyte hydrogel-forming polymers, are greatly depressed by the high concentration of the dissolved electrolyte normally present in the urine. The 4-, 0 concentration of this dissolved electrolyte, expressed as percent in weight of NaGI, can be as high as 0.9% (physiological saline) or higher. It is known that reducing the concentration of electrolyte dissolved in the urine (for example, by dilution with distilled water) can greatly increase the absorbent capacity of a polyelectrolyte hydrogel-forming polymer. Thus, for example, when Jayco synthetic urine is used to measure the gel volume of a partially neutralized sodium polyacrylate hydrogel-forming polymer, a 10-fold dilution of Jayco with the Jfí distilled water may result in approximately a 3-fold increase in gel volume. It is known that the concentration of electrolyte dissolved in a solution The aqueous can be reduced by the "reaction of the solution" with a mixed stratum ion exchange resin (the ion exchange columns are often used commercially to deionize the water). The concentration of electrolyte is reduced by the combined effect of (i) the exchange of the dissolved cations (for example Na +) in the 4 4. aqueous solution with H + from the cation exchange resin and (ii) the exchange "-" i 25 of the dissolved anions (for example CI ") with OH" of the anion exchange resin. The H + and OH "of the resin are combined from the solution to produce H2O This is the reaction of H + and OH" to form H20 which leads to the transfer of the anions and dissolved cations from the solution onto their respective resins, resulting in a reduction in the concentration of the electrolyte in the solution. Generally, mixed layer resins contain approximately equal equivalents of exchange functional groups - 5 anion and cation exchange. The particles of the anion and cation resins are intimately mixed in a desirable manner and / or have high surface areas with the - "* purpose of shortening the diffusion distances and increasing the ion exchange coefficients.The ion exchange resins have been used to increase the -} Absorbent rapacity of absorbent articles containing hydrogel-forming polymers. See, for example, U.S. Patent No. 4,818,598 issued April 4, 1989 to Wong. However, the need to incorporate large amounts of resin or ion exchange resins has little or no absorbent capacity which generally increases the volume of the absorbent article to an unacceptable degree. It is known that a mixture of (i), an anionic polymer forming M hydrogel in its acid form and (ii) a hydrogei-forming cationic polymer in its base form has the potential to function as a mixed stratum ion exchange system with respect to the reduction of the electrolyte concentration in solution.

In addition, if the hydrogel-forming anionic polymer in a mixed strand ion exchange system is a weak acid and part in its non-neutralized form, then the resulting exchange of H + by, for example, Na + results in the conversion of the forming polymer of anionic hydrogel from its non-neutralized form to the neutralized form. In this way, the osmotic driving force for swelling (and this In this manner, the absorption capacity of the hydrogel-forming polymer) of a weak acid hydrogel-forming anionic polymer increases as a result of ion exchange in a mixed stratum ion exchange system. Similarly, if the hydrogel-forming cationic polymer in a mixed stratum ion exchange system is a weak base and part in its non-neutralized form, then the ? resulting exchange of OH ", for, for example, CI" (or the addition of HCl to a neutral amino group), results in the conversion of the hydrogel-forming cationic polymer from its unneutralized form to the neutralized form. Therefore, the osmotic conduction force for the swelling of a weak base hydrogel-forming cationic polymer also increases as a result of ion exchange in a mixed stratum ion exchange system. Whether or not the hydrogel-forming polymers in a system? Ie ion exchange! mixed stratum are weak / strong acids or weak / strong bases, the reaction of an aqueous solution of the electrolyte with a mixed stratum ion exchange system results in at least some reduction of the electrolyte concentration, which results in at least some increase in the osmotic driving force for swelling. As a result of the effects combined of (i) the reduction in the concentration of the electrolyte and (ii) the conversion (if necessary) from a form less capable of inflating to a shape capable of further swelling, the hydrogell exchange-forming polymer system ionic mixed stratum, where the anionic and cationic hydrogel-forming polymers each start in their non-neutralized forms, has the potential to supply an osmotic force of • Increased conduction for swelling in relation to a mixture of comparable anionic and cationic hydrogel-forming polymers where each part departs in its neutralized forms. The use of ion exchange hydrogel-forming polymers of mixed stratum to increase the absorption capacity has been described in PCT applications Nos. WO 96/17681 (Palumbo, published June 13, 1996), WO * 25 96/15162 (Fornasari et al., Published May 23, 1996) and in United States Patent No. 5,274,018 (Tanaka, issued December 28, 1993).

The degree to which an ion exchange hydrogel-forming polymer system of the mixed stratum can potentially reduce the electrolyte concentration depends on (i) the meq / g ion exchange capacity of the anionic and cationic hydrogel-forming polymers, (I) the pKa and pKb (and thus the limit of the reaction) of the anionic and cationic hydrogel-forming polymers; (iii) meq / l of the electrolyte in the aqueous solution; and (iv) the l / g ratio of the aqueous electrolyte solution to the ion exchange hydrogel-forming polymers. For a given mixed stratum ion exchange capacity, the pKa and pKb, and the electrolyte concentration, the reduction in electrolyte concentration is maximized by ÍS0 minimize the volume of total solution in contact with the ion exchange hydrogel-forming polymers. In an absorbent structure (for example, a mixture of hydrogel and fiber-forming polymers), only a part of the total fluid is absorbed by the hydrogel-forming polymer. The balance of the fluid is absorbed by other components (for example, in the pores formed by the fiber structure). Without However, even though this fluid is not absorbed by the hydrogel-forming polymer, the electrolyte in this fluid can diffuse towards the hydrogel-forming polymer and from this __ & * 4 'way to raise the electrolyte concentration within a higher level than if the external fluid was not present. If the object is to use an ion exchange hydrogel forming polymer system from the mixed stratum to increase capacity As the absorbent is then absorbed, the potential benefits of the ion exchange are lessened as the percentage of the hydrogel-forming polymer in the absorbent structure decreases. In contrast, reducing the amount of fiber (or other components of non-hydrogel-forming polymers capable of absorbing fluids), reduces the amount of extra solution and thus the amount of extra salt that must be exchanged in order to • 25 to achieve a given reduction in electrolyte concentration. Therefore, in principle, when a mixed-layer ion-exchange hydrogel-forming polymer system is incorporated into an absorbent structure, it can benefit to a greater extent the ion exchange when it is incorporated at high concentrations against a low concentration. . The above absorbent structures have generally comprised relatively low amounts (eg, less than about 50% by weight of these hydrogel-forming absorbent polymers, see for example, U.S. Patent No. 4,834,735 (Alemay et al.), Issued on May 30, 1989 (preferably from about 9 to about 50% hydrogel-forming absorbent polymer in the fibrous matrix) There are several reasons for this: The hydrogel-forming absorbent polymers used in the above absorbent structures have not generally had a absorption that would allow them to rapidly absorb bodily fluids, especially in "jet" situations, this has required the inclusion of fibers, typically wood pulp fibers, to serve as temporary deposits to keep the fluids discharged until they are absorbed by the hydrogel-forming absorbent polymer, most importantly e, many of the known hydrogel-forming absorbent polymers exhibit gel blocking. The blockage of gei occurs when the particles of the hydrogel-forming absorbent polymer are wetted and the particles swell to inhibit the transmission of fluid to other regions of the absorbent structure.The wetting of these other regions of the absorbent member therefore takes place at Through a very slow diffusion process, in practical terms, this means the acquisition of fluids by the absorbent structure which is much slower than the rate at which the fluids are discharged, especially in jet situations. they can still take place long before the particles of the hydrogel-forming absorbent polymer in the absorbent member are completely saturated or before the fluid can diffuse or transmit by wicking by passing the "blocking" particles in the prayer of the absorbent member Gel blocking can be a particularly acute problem if the polymer particles Hydrogel-forming absorbent do not have the proper gel strength and shape or spread under stresses once the particles swell with the absorbed fluid See U.S. Patent No. 4,834,735 (Alemany et al.), issued May 30, 1989. This gel blocking phenomenon has typically necessitated the use of a fibrous matrix in which the particles of the hydrogel-forming absorbent polymer are dispersed. This fibrous matrix keeps the particles absorbing polymer forming hydrocje! separated one from the other. This fibrous matrix also provides a capillary structure that allows fluid to reach the hydrogel-forming absorbent polymer located in regions far from the initial point of fluid discharge. See U.S. Patent No. 4,834,735 (Alemay et al.), Issued May 30, 1989. However, the dispersion of the hydrogel-forming absorbent polymer in a matrix - 15 fibrous at relatively low concentrations, in order to reduce or avoid gel blockage can reduce the total fluid storage capacity of structures M < * _. thinner absorbent. Using lower concentrations of these hydrogel-forming absorbent polymers somewhat limits the real advantage of these materials, I know your ability to absorb and retain large amounts of body fluids by .20 given volume. In addition, from the increase in gel strength, other physical and chemical characteristics of these hydrogel-forming absorbent polymers have been manipulated to reduce gel blockage, a feature being particle size and especially the particle size distribution of the polymer. absorbent trainer ^ 25 hydrogel used in the fibrous matrix. For example, the particles of the hydrogel-forming absorbent polymer having a particle size distribution such that the particles have an average particle size in excess of greater than or equal to about 400 microns have been mixed with hydrophilic fibrous materials to reduce the gel blocking and to help maintain an open capillary structure within the absorbent structure to increase the planar transport of fluids away from the initial discharge area to the rest of the absorbent structure. In addition, the particle size distribution of the hydrogel-forming absorbent polymer can be controlled to improve the absorptive capacity and efficiency of the particles employed in the absorbent structure. See U.S. Patent No. 5,047,023 (Berg), issued September 10, 1991. However, still adjusting the particle distribution does not, by itself, lead to absorbent structures that may have relatively high concentrations of these polymers. hydrogel-forming absorbers. See U.S. Patent No. 5,047,023, (at optimum fiber-to-particle ratio based on cost / performance which is from about 75:25 to about 90:10). Another feature of these hydrogel-forming absorbent polymers that has been observed is the level of extractables present in the polymer itself. See U.S. Patent No. 4,654,039 (Brandt et al.), Issued March 31, 1987 (reissued on April 19, 1988 as remitted United States Patent No. 32,649). Many of these hydrogel-forming absorbent polymers contain significant levels of extractable polymer material. This extractable polymer material can be leached from the resulting hydrogel by body fluids (eg, urine), during the period of time, such that the body fluids remain in contact with the absorbent hydrogel-forming polymer. It is believed that this polymer material extracted by the body fluid in this manner can alter both the chemical and physical characteristics of the body fluid to the point that the fluid is absorbed more slowly and more poorly retained by the hydrogel in the absorbent article. Another feature that has been observed in minimizing gel blocking is the improvement of the capillary capacity of these absorbent hydrogel-forming polymers. In particular, it has been suggested that the particles of these absorbent polymers * Hydrogel formers are formed in aggregate macrostructures cross-linked between particles typically in the form of sheets or strips. See U.S. Patent No. 5,102,597 (Roe et al.), Issued April 7, 1992; U.S. Patent No. 5,124,188 (Roe et al.), issued June 23, 1992; and the patent of the United States No. 5,149,344 (Lahrman et al.), Issued September 22, 1992. Due to the nature of the absorbent polymer particle that is retained, These macrostructures provide pores between adjacent particles that are interconnected in such a way that the macrostructure is fluid permeable (ie, it has capillary transport channels). Due to cross-particle lattice links formed between the particles, the resulting macrostructures also have improved structural integrity, increased fluid acquisition and distribution coefficient, and minimum gel blocking characteristics. Yet another feature of the art that has been known for some time as a measure of gel blocking is the wettability of demand or gravimetric absorbency of these absorbent hydrogel-forming polymers. See, for example, U.S. Patent No. 5,562,646 (Goldman et al.), Issued October 8, 1996 and U.S. Patent No. 5,599,335 (Goldman et al.), Issued February 4, 1997. , where the wettability of demand / gravimetric absorbency is referred to as Performance Under Pressure (PUP).

In a PUP experiment, an initially dry MAG is placed at a 100% concentration in a piston / cylinder apparatus (where the bottom of the cylinder is permeable to the solution, but impermeable to the gelling absorbent material), under mechanical confinement pressure and is allowed to absorb synthetic urine under demand / absorbency conditions at zero hydrostatic suction and high mechanical pressure. The "PUP" capacity is defined as the g / g absorption of the Jayco synthetic urine by a 0.032 g / cm2 layer of the hydrogel-forming absorbent polymer, while being confined under an applied pressure of five Kpa (approximately 0.7 psi). ) for a period of one hour. The hydrogel-forming polymer is considered to have desirable PUP properties without it absorbing at least 23 g / g after one hour. A high PUP capacity is a critically important property for a hydrogel-forming polymer when it is used at high concentrations in an absorbent structure. Although maximized the concentration of ion exchange hydrogel-forming polymers, mixed stratum, an absorbent structure increases the osmotic conduction force for swelling, this increase in driving osmotic force has not resulted in early improvement in the performance of absorbency in terms of PUP capacity. It is believed that the performance deficiency at the high concentration of the current mixed strand ion exchange hydrogel-forming polymers results at least in part from the constituent polymers in the mixed stratum system and its mixture which is not optimized for use at high concentrations and high confining pressures. As a result, the current mixed strand ion exchange hydrogel-forming polymers tend to gel blocking under a confining pressure, exhibit low absorption coefficients, under PUP absorption conditions, and have a low absorption capacity. PUP after a reasonable period of time. As a result, the PUP absorption of the ion exchange hydrogel-forming polymers of the mixed stratum is not significantly greater than the PUP absorption and a comparable mixture of the cationic and anionic hydrogel-forming polymers, where the * polymers are neutralized before of the measurement of the PUP or of any anionic or cationic hydrogel-forming polymer by itself, where the polymers are neutralized before the measurement of the PUP. (These can also exhibit a low value for saline flow conductivity (SFC), a low value for the porosity of the hydrogel layer (PHL), and slow ion exchange coefficients, see discun below. Current mixed-layer hydrogel formers at high concentrations is especially worthy of attention, given the importance of using polymer-forming polymers.

- -.- #? AQ, hjdroge! at high concentrations in absorbent articles such as diapers. For absorbent structures having relatively high concentrations of these hydrogel-forming absorbent polymers, other characteristics of these absorbent polymers are also important. It has been found that the opening or porosity of the hydrogel layer formed when these polymers absorbers in the presence of body fluids is relevant to determining the ability of these absorbent polymers to acquire and transport the fluids, especially when the absorbent polymer is present at high concentrations in the absorbent structure. Porosity refers to the fractional volume that is not occupied by the solid material. For a hydrogel layer formed entirely from the * 20 absorbent hydrogel-forming polymer, the porosity is the fractional volume of the layer that is not occupied by the hydrogel. For an absorbent structure containing the hydrogel, as well as other components, the porosity is the fractional volume (also referred to as hollow volume), which has not been occupied by the hydrogel, or other solid components eg, fibers). The opening or porosity of a layer of The hydrogel formed from the hydrogel-forming absorbent polymer can be defined in terms of the porosity of the hydrogel layer (see, for example, U.S. Patent No. 5,562,646). A good example of a material having a very high grade opening is a weft laid with air of wood pulp fibers. For example, the fractional degree of the opening of a weft placed with air of wood pulp fibers (for example, having a density of 0.15 grams / cc) is estimated to be 0.8-0.9, when it is wetted or moistened with the body fluids under a confining pressure of 0.3 psi. It has been found that the PHL value of the hydrogel-forming absorbent polymer does not have to approximate that of the air-laid web of the wood pulp fibers in order to obtain the substantial performance benefits when these polymers are present at high concentrations. These benefits include (1) increased hollow volume in the resulting hydrogel layer to acquire and distribute the fluid; and (2) increased total amount of fluid absorbed by the absorbent polymer under conditions of demand wettability / gravimetric absorbency (ie, for fluid storage). The increased porosity can also provide additional performance benefits such as: (3) increased permeability of the resulting hydrogel layer to acquire and distribute the fluid; (4) improved wicking transmission properties for the resulting hydrogei layer, such as the capillary action of the fluid upward against the gravity pressures or fluid partitioning away from the acquisition layer; (5) Improved swelling rate properties for the resulting hydrogel layer to allow for faster fluid storage. A hydrogel-forming polymer is considered to have PHL properties if its PHL value is at least about 0.15. Another important property at higher concentrations of these hydrogel-forming absorbent polymers is their permeability / flow conductivity. The permeability / flow conductivity can be defined in terms of its saline flow conductivity values. SFC measures the ability of a material to transport saline fluids, such as the ability of the hydrogel layer formed from the swollen hydrogel-forming absorbent polymer to carry body fluids. Typically, an air pulp fiber web (for example, having a density of 0.15 g / cm 3) will exhibit an SFC value of about 200 x 10"7 cm 3 sec / g. capable of using the hydrogel-forming absorbent polymers that come closest to an air pulp fiber-laid web in terms of SFC It is considered that a hydrogel-forming polymer has desirable permeability properties if its SFC value is at least about 30x10"7 cm3 sec / g. . _ ". Another factor that has to be considered in order to have total advantage! of the porosity and permeability properties of the hydrogel layer formed of these absorbent polymers is the wet integrity of the region or regions in the absorbent member comprising these polymers. For hydrogel-forming absorbent polymers having relatively high porosity and SFC valuesIt is important that the region or regions in which the polymers are present have good wet integrity. By "wet integrity", it is implied that the region or regions in the absorbent member having the high concentration of the hydrogel-forming absorbent polymer has sufficient integrity in a dry, partially moist state, and / or a wet state such that the physical continuity (and thus the ability to acquire and transport fluid to and through the adjoining interstitial / capillary gaps) of the hydrogel formed upon swelling in the presence of body fluids is not substantially altered or broken, even when It is subjected to normal conditions of use. During normal use, the absorbent cores in the absorbent articles are typically subjected to varying tensile and torsional strengths and direction. These tensile and torsional forces include the bulge in the crotch area, the stretching and torsional forces as the person using the absorbent article walks, bends, flexes and the like. If wet integrity is inadequate, these tensile and torsional forces can potentially cause an alteration and / or an interruption in the physical continuity of the hydrogel, such that its ability to acquire and transport fluids into and through adjacent gaps and capillaries is degraded, for example, the hydrogel layer can be partially separated, totally separated, have introduced spaces, have areas that are significantly thinned and / or broken into a plurality of significantly smaller segments. This alteration can reduce or completely negate any of the advantageous porosity and permeability / flow conductivity properties of the hydrogel-absorbing polymer. Accordingly, it would be desirable to be able to provide mixed layer ion exchange hydrogel-forming polymers capable of absorbing an increased amount of a urine electrolytic solution under PUP absorption conditions, within a reasonable period of time relative to a mixture _15 comparable to the constituent hydrogel forming polymers, each in its neutralized forms. It would also be desirable to be able to provide polymers i. Mixed layer ion exchange hydrogel formers capable of absorbing a larger amount of a PUP solution in a reasonable period of time. It would also be desirable to provide an absorbent structure containing a - high concentration of a mixed layer ion exchange hydrogel-forming polymer capable of absorbing an increased amount of a urine electrolyte solution under PUP absorption conditions in a reasonable period of time relative to a comparable mixture of the constituent hydrogel forming polymers, each in their neutralized forms. It would also be desirable provide a mixed strand ion exchange hydrogel forming polymer having high SFC and PHL values.

BRIEF DESCRIPTION OF THE INVENTION The present invention relates to absorbent materials and Absorbent members useful in the containment of body fluids such as urine. In one aspect, the invention relates to a mixture of ion-exchange hydrogel-forming cationic polymers and ion exchange-forming hydrogel-forming anionic polymers (referred to herein as a mixed strand ion-exchange hydrogel-forming polymer composition), wherein the mixture exhibits increased absorbency of a urine electrolyte solution under (PUP) absorption conditions in a reasonable period of time, relative to a comparable mixture of the constituent hydrogel forming anionic and cationic polymers, each in its own neutralized forms. The invention also relates to absorbent members having at least one region comprising such gel-mixed hydrogel-forming polymer compositions of mixed stratum at a concentration of about 60 to 100% by weight of the hydrogel-forming polymer of ion exchange In another aspect, the invention relates to an ion-exchange hydrogel-forming polymer composition of mixed stratum having a performance capacity value under pressure at 225 minutes of at least about 25 g / g under a pressure of confinement of 0.7 psi (5 kPa). The invention further relates to absorbent members having at least one region comprising such mixed strand ion exchange hydrogel-forming polymer compositions, at a concentration of about 60 to 100%, by weight, of the ion exchange hydrogel-forming polymer. .

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a cross-sectional view of an absorbent article showing an absorbent core according to the present invention. Figure 2 is a cross-sectional view of an absorbent article showing another absorbent core according to the present invention. Figure 3 is a cross-sectional view of an absorbent article showing another absorbent core according to the present invention. Figure 4 is a cross-sectional view of an absorbent article 10, showing another absorbent core according to the present invention. Figure 5 is a cross-sectional view of an absorbent article showing an absorbent core alternate to that shown in Figure 4. Figure 6 is a cross-sectional view of an absorbent article showing another absorbent core alternative to that shown in the Figures 4 and 5. FIG. 7 represents a schematic view of an apparatus for measuring the value of the saline flow conductivity of the absorbent polymers forming hildose. Figure 8 depicts an enlarged sectional view of the piston / cylinder assembly shown in Figure 7. * Figure 9 depicts a plan view of the lower part of the piston head of the piston / cylinder assembly shown in the Figure 8. Figure 10 represents a schematic view of an apparatus for measuring the performance under pressure (PUP) of hydrogel-forming absorbent polymers. - Figure 11 represents an enlarged sectional view of the piston / cylinder assembly shown in Figure 10.

Figure 12 depicts a sectional view of the piston / cylinder assembly used to measure the porosity of hydrogel-forming absorbent polymers. Figure 13 depicts a plan view of the lower part of the piston head of the piston / cylinder assembly shown in Figure 12.

DETAILED DESCRIPTION OF THE INVENTION A. Definitions ... As used herein, the term "body fluids" includes urine, menstruation, and vaginal discharge As used herein, the term "z dimension" refers to the dimension octagonal to the length and width of the body. member, core or article The dimension z usually corresponds to the thickness of the member, core or article 15. As used herein, the term "dimension XY refers to the plane orthogonal to the thickness of the member, core or article. The X-Y dimension usually corresponds to the length and width of the member to the core or article. As used herein, the term "absorbent core" refers to the component of the absorbent article that is primarily responsible for the fluid handling properties of the article, including the acquisition, transport, distribution and storage of body fluids. As such, the absorbent core typically does not include the backsheet or the topsheet of the absorbent article. As used herein, the term "absorbent member" refers to the components of the absorbent core that typically provide one or more of the fluid handling properties, eg, fluid acquisition, fluid distribution, fluid transportation, fluid storage, etc. The absorbent member may comprise the total absorbent core or only a portion of the absorbent core, ie, the absorbent core may comprise one or more absorbent members. As used herein, the terms "region" or "regions," or "zone" or "zones" refer to parts or sections of the absorbent member. As used herein the term "layer" refers to an absorbent member whose main dimension is X-Y, that is, along its length and width. It should be understood that the term layer is not necessarily limited to single layers or sheets of material. In this way, the layer may comprise laminates or combinations of various sheets or webs of the type of materials required. Accordingly, the term "layer" includes the terms "layers" or "layers". For purposes of the present invention, it is also to be understood that the term "top" refers to absorbent members, such as layers, that are more close to the user of the absorbent article and typically face towards the topsheet of an absorbent article; conversely, the term "lower" refers to the absorbent members that are farthest from the absorbent article and typically face toward the backsheet. As used herein, the term "comprising" means various components, members, steps and the like, which may be used together with the present invention, Therefore, the term "comprising" embraces the more restrictive terms "consisting essentially of", and "consisting of" the latter more restrictive terms having their standard meaning as understood in the art, All percentages, ratios and proportions used herein, are by weight unless otherwise specified.

B. Materiales and components of the Absorbing Member 1. Ion exchange Hydrogel Foaming Abrasive Polymers, from Mixed stratum a. Chemical composition (1). Cationic Polymers Hydrogel-forming absorbent polymers useful as the polymer or cationic polymers include a variety of water-insoluble but water-swellable polymers capable of absorbing large amounts of fluid. The cationic types can have a multiplicity of cationic functional groups, such as N-alkyl amine, N, N'-dialkylamine groups., N, N'N "trialkylamine, N, N ', N, N" "- tetraqulammonium Examples of the polymers suitable for use herein include those which are prepared from polymerizable monomers containing unsaturated cation. monomers include olefinically unsaturated amines and substituted amines containing at least one carbon-to-carbon olefinic double bond, more specifically, these monomers may be selected from olefinically unsaturated alkylamines, dialkylamines, triaquyamines, and tetralkylammonium hydroxide such as vinylamine, allylamine , 4-aminobutene, 5-aminopentene and its derivatives N-alkyl, dialkyl, and tri-alkyl, the esters of acrylate and methacrylate and amides containing alkylamines, dialkylamines, trialkylamines, tetralkylammonium hydroxide groups such as N, N-dimethylaminoethyl (meth) acrylate, N, N, N-trimethylaminoethyl (meth) acrylamide, N, N, N-trimethylaminoethyl (meth) acrylamide, and the like and mixtures thereof The cationic types can also comprise polyelectrolytes based on N, N-dialkyl, N, N-diallylammonium salts such as dimethyldiallylammonium salts (see, for example, PCT publication No. WO 96/17681, published by Palumbo on 13 June 1996, and PCT publication No. WO 96/15162, published May 23, 1996 by Fornasari, both of which are incorporated herein by reference. The cationic types may also comprise light-anionic and non-ionic base polymers slightly networked to which the cationic functional groups are covalently attached. Examples of suitable base polymers include polyacrylamide, Poly (meth) acrylic acid, polyvinyl alcohol, maleic anhydro ethylene copolymer, isobutylene maleic anhydride copolymer, polyvinyl ether, polyvinyl sulfonic acid, polyvinyl pyrrolidone, and polyvinyl morpholine, and starch grafted with hydrolyzed acrylonitrile. The cationic types may also comprise polyethyleneimine and its derivatives (eg, alkyl derivatives). Cationic types may also comprise polyelectrolytes based on polysaccharides, such as aminoethyl starch, aminyoethyl cellulose, dimethylaminoethyl starch, dimethylaminoethyl cellulose, trimethylammoniomethyl hydroxide starch, trimethylammoniumethyl hydroxide cellulose and the like and polyelectrolytes based on polyamino acid, such as polysterine, polylysine and the like as well as other polyelectrolytes that are not prepared from polymerizable unsaturated monomers. See, for example, PCT publication No. WO 96/15154, published May 23, 1996 by Fornasari et al., Which is incorporated herein by reference. Some non-base monomers may also be included, usually in minor amounts, when preparing the hydrogel-forming absorbent formers herein. Although the hydrogel-forming absorbent cationic polymer is preferably of a (homogeneous) type, mixtures of cationic polymers can also be used in the present invention. When used by itself for absorbency applications the cationic hydrogel-forming absorbent cationic polymers start from about 50 to about 95% neutralized. When used as part of a mixed strand ion exchange composition, the cationic hydrogel-forming absorbent polymer ranges from about 50 to about 100%, preferably from about 80% to about 100%, more preferably from about 90% to about 100. % in the non-neutralized base form. When used as part of a mixed strand ion exchange composition, the cationic ion exchange hydrogel-forming absorbent polymer is at least partially converted to its neutralized form as a result of the salt reduction ion exchange process. The resulting cationic polymer is preferably at least 50%, more preferably at least 75% even more > _t J Ov preferably at least 90%, converted to its neutralized form as a result of the ion change. In order to maximize the ion exchange capacity of the mixed layer ion exchange hydrogel-forming polymer, it is desirable that the hydrogel-forming cationic polymer has a high anion exchange capacity for grams Thus, it is preferred that the anion exchange capacity of the hydrogel-forming cationic polymer be at least about 4 meg / g, more preferably at least about 6 meq / g, even more preferably at least about 10. meq / g, even more preferably at least 15 meq / g, most preferably at least about 20 - 20 meq / g. (2). Anionic Polymers Hydrogel-forming absorbent polymers useful as the polymer or anionic polymers typically have a multiplicity of anionic groups, functional, such as sulfonic acid, and more typically carboxy groups. Examples of suitable polymers for use herein include those which are prepared from polymerizable monomers containing unsaturated acid. Thus, these monomers include olefinically unsaturated acids and anhydrides containing at least one olefinic carbon-to-carbon double bond. More specifically, these monomers can be selected from olefinically unsaturated carboxylic acids and acid anhydrides, olefinically unsaturated sulfonic acids and mixtures thereof. The anionic types may also comprise polyelectrolytes based on polysaccharides, such as carboxymethyl starch and carboxymethyl cellulose, and polyelectrolytes based on polyamino acid such as polyaspartic acid as well as other polyelectrolytes that are not prepared from polymerizable unsaturated monomers. For a description of the polyamino acid hydrogel-forming polymers, see, for example, U.S. Patent No. 5,247,068 issued September 21, 1993 to Donachy et al., Which is incorporated herein by reference. Some of the non-acidic monomers may also be included, usually in minor amounts, when preparing the anionic hydrogel-forming absorbent polymers herein. These non-acidic monomers can include, for example, the water-soluble or water-dispersible esters of the acid-containing monomers, as well as the monomers that do not contain carboxylic acid sulfonic acid groups at all. Optional non-acidic monomers may thus include monomers containing the following functional type groups. Carboxylic acid or sulfonic acid esters, hydroxyl groups, amide groups, amino groups, nitrile groups, quaternary ammonium salt groups, aryl groups, (for example, phenyl groups, such as those derived from styrene monomer) and dienes such as butadiene and isoprene. These non-acidic monomers are well known materials and are described in greater detail, for example, in U.S. Patent No. 4,076,663, (Masuda et al.), Issued February 28, 1978; and in the patent of the United States No. 4,062,817 (Westerman), issued December 13, 1977, both of which are incorporated by reference. The carboxylic acid and olefinically unsaturated carboxylic acid anhydride monomers include the acrylic acids typified by acrylic acid itself, methacrylic acid, ethacrylic acid, α-chloroacrylic acid, α-cyanoacrylic acid, β-methylacrylic acid (crotonic acid), -phenylacrylic acid, ß-acryloxypropionic acid, sorbic acid, omegalaic acid, cinnamic acid, p-chlorocinnamic acid, ß-sterilacrylic acid, itaconic acid, citroconic acid, mesaconic acid, glutaconic acid, aconitic acid, maleic acid, fumaric acid, tricarboxyethylene and maleic acid anhydride. The monomers of acid s? ón? co olefínicamerñe insa? urado ¡ncluyéf? sulphonic acids of aliphatic or aromatic vinyl, such as vinyl sulfonic acid, allyl sulfonic acid, vinyl toluene or sulfonic acid, and styrene sulfonic acid; acrylic and sulphonic methacrylic acid, such as sulfoethyl acrylate, sulfoethyl methacrylate, sulfopropyl acrylate, sulfopropyl methacrylate, 2-hydroxy-3-methacryloxypropyl sulfonic acid and 2-acrylamide-2-methyl propan sulfonic acid. Preferred anionic hydrogel-forming absorbent polymers for use contain carboxy groups. These polymers include graft copolymers of hydrolyzed starch-acrylonitrile, partially neutralized graft copolymers of hydrolyzed starch-acrylonitrile, graft copolymers of acrylic acid-starch, partially neutralized graft copolymers of starch-acrylic acid, saponified copolymers of acetate- acrylic ester, hydrolyzed acrylonitrile or acrylamide copolymers, polymers lightly crosslinked in the network of any of the above copolymers, polyacrylic acid, and polyacrylic acid polymers lightly crosslinked in the network. These polymers can be used either alone or in the form of a mixture of two or more different polymers. Examples of these polymer materials are disclosed in U.S. Patent No. 3,661,875, U.S. Patent No. 4,076,663, U.S. Patent No. 4,093,776 U.S. Patent No. 4,666,983 and U.S. Pat. of the United States No. 4,734,478. The most preferred polymer materials for use in the preparation of the hydrogel-forming absorbent anionic polymers are the lightly cross-linked polymers of polyacrylic acids and their starch derivatives. Cross-linking in the network makes the polymer substantially insoluble and, in part, determines the absorptive capacity and the characteristics of the removable polymer content of the hydrogel-forming absorbent polymers. The process for network cross-linking of these polymers and typically re-crosslinking agents. they are described in greater detail in U.S. Patent No. 4,076,663. Although the hydrogel-forming absorbent anionic polymer is preferably of one type (ie, homogeneous, mixtures of the anionic polymers can also be used in the present invention, for example mixtures of starch graft copolymers can be used in the present invention). Acrylic acid and slightly cross-linked polymers in the polyacrylic acid network When used by themselves for the application of absorbency, the anionic hydrogel-forming absorbent polymers start from about 50 to about 95%, preferably about 75% neutralized. this way, the hydrogel-forming polymer of polyacrylic acid lightly crosslinked in the preferred network, is preferably -25% in the form of non-neutralized acrylic acid and about 75% in the neutralized acrylate form (e.g., sodium acrylate). When used as part of an ion exchange composition of this mixed time, the anionic hydrogel-forming absorbent polymer part from about 50% to about 100%, preferably from about 80% to about 100%, more preferably from about 90% to about 100% in the non-neutralized acid form. In this manner, the hydrogel-forming polymer of the polyacrylic acid lightly cross-linked in the network most preferably part from about 90% to about 100% in the form of non-neutralized acrylic acid. When used as part of a mixed layer ion exchange composition, the anionic ion exchange hydrogel-forming absorbent polymer is partially converted to its neutralized form as a result of ion exchange. The resulting single polymer is preferably at least 50%, more preferably at least 75%, still more preferably 90% converted to its neutralized form as a result of the ion exchange. In order to maximize the ion exchange capacity of the mixed strand ion exchange hydrogel forming polymer composition, it is desirable that the anionic ion exchange hydrogel-forming polymer has a high cation exchange capacity per gram. Therefore, it is preferred that the cation exchange capacity of the anionic ion exchange hydrogel-forming polymer be at least about 4 meq / g, more preferably at least about 8 meq / g, even more preferably at least about 10. meq / g, most preferably at least about 13 meq / g. (3). Common Composition and Properties of the Material In order to maximize the ion exchange capacity of the mixed strand ion exchange hydrogel-forming polymer composition, it is desirable that the mixed stratum composition comprises equivalents at about equal to the capacity of anion exchange and cation exchange. However, it may be desirable to have a little more equivalents of the anionic or ion exchange hydrogel-forming cationic polymer to alter the pH of (for example, acidifying), the ion exchanged urine, etc. The ion exchange capacity of the approximate mixed stratum of the mixed strand ion exchange hydrogel-forming polymer composition can be calculated from the relative ionic exchange weights and capacities of the constituents of the anionic and cationic forming polymer. of ion exchange hydrogel. Thus, for example, an ion exchange composition comprising approximately equal equivalents of strongly acidic hydrogel-forming anionic polymer having a cation exchange capacity of about 4.8 meq / g and a hydrogel-forming cationic polymer of strong base having an anion exchange capacity of approximately 7.0 meq / g would comprise approximately 0.65 parts of the hydrogel-forming anionic polymer and approximately 0.35 parts of the hydrogel-forming cationic polymer with a mixed strand ion exchange capacity of approximately 3.1 meq. / g. It is preferred that the ion exchange capacity of the stratum of the stratum hydrogel-forming polymer composition itself be at least about 2 meq / g, more preferably at least 4 meq / g even more preferably at least about 6 meq / g. / g, and most preferably at least about 7 meq / g. The cationic and anionic hydrogel-forming absorbent polymers useful in the present invention, in the neutralized form, each preferably have relatively high PUP, SFC and PHL values. The capacity of PUP at 0.7 psi in 60 minutes is preferably at least about 23 g / g, more preferably at least 30 x 10-7 cm3 sec / g, more preferably at least 50 x 10"7 cm3 sec / g., more preferably at least 100 x 10"7 cm3 sec / g. The PHAL value is preferably at least about 0.15, more preferably at least 0.20, most preferably at least about 0.25.

In the mixed layer hydrogel-forming polymer composition, the forming polymer of one type can have a higher crosslink density than the hydrogel-forming polymer of another type, so that the properties of the gel can advantageously be improved ( for example PUP, SFC, PHL) of the mixture. The cationic and anionic hydrogel-forming polymers useful in the present invention may each have a shape, size and / or formology that varies over a wide range. These polymers may be in the form of particles that do not have a greater proportion from the largest dimension to the smallest dimension. For example, grains, powders, aggregates between particles, aggregates crosslinked between particles, and the like ^ and may be in the form of fibers, sheets, films, flakes and the like. The hydrogel-forming polymers may also comprise mixtures with low levels of one or more additives, such as, for example, silica powder, surfactants, binder glues, and the like. The components in this mixture can be physically and / or chemically associated in such a way that the component of the The hydrogel-forming polymer and the additive of the non-hydrogel-forming polymer are not easily physically separable. < «> * • _ Hydrogel-forming absorbent polymers can be? essentially non-porous (ie, without internal porosity), or have substantial external porosity. 20 For the particles as described above, the particle size is defined as the dimension determined by the sieve size analysis. Thus, for example, a particle that is retained in a standard United States test sieve with 710 micron openings (for example, the alternate screen designation of the US 25 series), is considered to have a size greater than 710 microns; a particle that passes through a sieve with apertures of 710 microns and that is retained in a sieve with openings of 500 microns (for example, the designation of the alternate sieve of the series No 35 of the United States), is considered to have a particle size of between 500 and 710, and a particle passing through a sieve with openings of 500 microns is considered to have a size of less than 500 microns. The average mass particle size of a given sample of the hydrogel-forming absorbent polymer particles is defined as the particle size that divides the sample in half on a mass basis, ie, half the sample in The weight will have a smaller particle size than the average mass size and half the sample will have a smaller particle size than the average mass size. Typically, a standard particle size plotting method (wherein the accumulated weight percent of the particle sample retained in or passed through a given sieve size aperture is plotted against the sieve size aperture) is used. in the role of probabilities), to determine the average particle size in mass when the mass value of 50% does not correspond to the size opening of a standard US test sieve. These methods for determining the particle sizes of the hydrogel-forming absorbent polymer particles are further described in U.S. Patent No. 5,061, 259 (Goldman et al.), Issued October 29, 1991, which is incorporated herein by reference. by reference. For the particles of the hydrogel-forming absorbent polymers in the present invention, the particles will generally vary in size from about 1 to about 2000 microns, more preferably from about 1000 microns. The average particle size in mass will generally be from about 20 to about 1500 microns, more preferably from about 50 microns to about 1000 microns, and even more preferably from about 100 to about 800 microns. Within these size ranges, it may be preferable to choose either larger or smaller particles depending on the need for faster or slower absorption synthetics. For example, for non-porous particles, the coefficient or rate of swelling will generally decrease with the increase in particle size. It may also be preferable to choose either larger or smaller particles or narrower size cuts (fractions), larger or smaller particles from the bulk volume in order to increase porosity (i.e., increase the value of PHL), increase the permeability of the gel layer (that is, increase the value of the saline flow conductivity), improve the properties of capillary action, etc.). For the particles of some hydrogel-forming absorbent polymers, it has been found that particle sizes generally greater than Gonna have narrower size-range cuts within the range of sizes previously specified have higher SFC values without any significant degradation in others. the properties of the hydrogel-forming absorbent polymer such as PHL, the performance capability under pressure (PUP) and the level of extractable polymer. Thus, for example, it may be useful to use a size cut that has an average mass size on the scale of about 500 to about 710 microns where only minimal mass fractions of the particles have sizes greater than about 710 microns or less than approximately 500 microns. Alternatively, a larger size cut of the particles generally has a scale of about 300 microns to about 800 microns which may be useful. Within these size ranges, it may be desirable to choose particles that have internal porosity capable of contributing to a swifter swelling of the hydrogel-forming polymer by body fluids. The internal porosity within the particle of the hydrogel-forming polymer can also contribute to the PHL value of the resulting hydrogel layer. Changes in this component of the total value of PHL may have a lesser impact on some of the PHL-dependent fluid handling properties (e.g. SFC) than changes in the PHL value component that come from the voids between the particles swollen from the hydrogel-forming polymer in the hydrogel layer. Mixed stratum ion exchange hydrogel-forming polymer compositions in high concentration absorbent cores can not adhere to solution flow, agitation, etc., to help transport the scripts between the particles and accelerate the rate of ion exchange. Therefore, it is desirable to have suitable particle morphologies to promote rapid ion exchange kinetics. Desirable morphologies include fibers of high surface area and mixed stratum aggregates of particles with high surface area (e.g., small and / or porous). Desirable morphologies also include (I) particles of, for example, the hydrogel-forming anionic polymer containing within discontinuous domains less than, for example, the hydrogel-forming cationic polymer (ii), particles containing bicontinuous domains of both anionic polymers and cationic hydrogel formers and (iii) particles of for example, the hydrogel-forming anionic polymer that is coated or coated with a surface layer of for example, the hydrogel-forming cationic polymer. The additional "desirable rate-by-regime" properties of the mixed-strand hydrogel-forming polymer composition can include a very high free swelling coefficient and a very fast absorption coefficient under PUP measurement conditions and pressures. . Certain types of shapes, aggregates, layer structures, microdomain structures, etc., can be advantageous for reducing the extremes of pH when combinations of strong and weak ion exchange hydrogel formers are used. Thus, for example, a layered or microdomain structure wherein a strong base anion exchange hydrogel-forming polymer is completely enclosed by a weak acid cation exchange hydrogel-forming polymer can ensure rapid neutralization and this way limit the diffusion of the free OH "out of the particle. b. Physical Properties (1). Performance under pressure (PUP) An essential feature of the mixed strand ion exchange hydrogel-forming absorbent polymers useful in the present invention is its demand absorbency under high confining pressure. This demand absorbency is defined in terms of the performance under pressure (PUP) of the mixed strand ion exchange compositions. The PUP capability measures the ability of a high base area or layer of the mixed stratum of the hydrogel-forming absorbent polymers to absorb body fluids under pressures of use. In one aspect, the present invention relates to the use of a mixed layer of hydrogel-forming polymers that exhibit improved absorbency of a urine electrolyte solution compared to a comparable mixture of the cationic and anionic polymers when each is used in its form neutralized. Preferable, the mixed stratum of the hydroge- forming polymers? will exhibit improved PUP capabilities relative to the comparable blend of the unneutralized polymer constituents when measuring PUP under a confining pressure of at least about 0.3 psi, preferably 0.7 psi, and most preferably 1.4 psi. It is preferred that relatively high PUP capacity values be achieved within a period of time that is less than, preferably significantly less than, the time of use (e.g., overnight) of the articles comprising the compositions of mixed stratum exchange. In this regard, the mixed stratum of the hydrogel-forming polymers will exhibit improved absorbency when PUP capacity is measured over a period of 225 minutes, preferably over a period of 60 minutes, more preferably over a period of 5 minutes. The improved mixed stratum of the ion exchange composition of the hydrogel-forming polymer of the present invention will be capable of absorbing at least about 20%, preferably at least 50%, more preferably at least about 100%, more urine Synthetic of a comparable mixture of the constituent hydrogel forming anionic and cationic polymers, each in its neutralized forms. Preferably, the improved mixed stratum of the ion exchange composition of the hydrogel-forming polymer of the present invention will be capable of absorbing at least about 20%, preferably at least about 50%, more preferably at least about 100%, more of etinetic urine than any of the constituents of the anionic or cationic hydrogel-forming polymers in their neutralized form. In another aspect, the present invention relates to a mixed layer ion exchange hydrogel-forming polymer composition having a PUP capacity after 225 minutes (preferably after 60 minutes), under a confining pressure of 0.7 psi. at least 25 g / g, more preferably at least 40 g / g, and even more preferably by at least 50 g / g. preferably, the PUP absorption capacity of the mixed strand ion exchange hydrogel-forming polymer composition after 225 minutes (preferably after 60 minutes), under a confining pressure of 1.4 psi is at least 20 g / g , more preferably at least 30 g / g, and even more preferably 40 g / g. Typically, the PUP absorption capacity after 225 minutes (after 60 minutes), under a confining pressure of 0.3 psi for the mixed layer ion exchange hydrogel-forming polymer composition, is at least 30 g / g , more preferably at least 45 g / g, and even more preferably at least 60 g / g. When hydrogel-forming absorbent polymers are incorporated into an absorbent member in high concentrations, polymers need to be able to absorb large amounts of body fluids in a reasonable period of time under pressures of use. Otherwise, the absorbent member will be less effective in absorbing the fluid, for example, partitioning the fluid from the acquisition components that provides the temporary handling capacity for this fluid. When this occurs, it is believed that the absorbent core is left with insufficient temporary handling capacity to contain subsequent jets of body fluid and may leak prematurely. Also, in order to be able to supply a high storage capacity from an absorbent core of minimum thickness and weight, the mixed layer of the hydrogel-forming absorbent polymers needs to have a PUP capacity. Polymer-forming polymers with PUP capability are also necessary to provide economical absorbent cores. The pressures of use exerted on the hydrogel-forming polymers include both mechanical pressures (e.g., exerted by the weight and movements of the user, bonding forces, etc.), and capillary pressures (e.g., resulting from the component or components of acquisition in the abetorbent core that temporarily retains the fluid before it is absorbed by the hydrogel-forming absorbent polymer). It is believed that a total pressure of about PUP is a reflection of the sum of these pressures on the mixed layer of the hydrogel-forming absorbent polymers as it absorbs body fluids under conditions of use. However, both of the upper and lower pressures (for example, on the scale of about 0.7 psi (5 kPa), can also be exerted by the hydrogel-absorbing polymer as it absorbs bodily fluids under conditions of use. It is desirable that the mixed layer ion exchange hydrogel forming polymers of the present invention have a high PUP capacity on a pressure scale of about 0.3 psi to about 1.4 psi). For mixed layer ion exchange hydrogel-forming polymers the coefficient of PUP absorption can be impacted by the coefficient of the ionic exchange kinetics. In a PUP experiment this can sometimes result in a slower PUP absorption coefficient for a mixed strand ion exchange hydrogel-forming polymer composition, than for a comparable mixture of the anionic and cationic polymeric hydrogel-forming polymers, wherein the hydrogel-forming polymers are in their neutralized forms. By a "comparable mixture", a mixture is meant where the proportion or proportions in peeo of the anionic and cationic hydrogel polymers are approximately equal. As a result, it may be reasonable to allow a slightly longer period of time for the absorption of PUP than the 60 minutes used in the PUP measurement described in for example U.S. Patent No. 5,562,646 (Goldman et al. ), issued October 8, 1996. A reasonable period of time for a mixed strand ion exchange hydrogel-forming polymer composition can be as long as about 225 minutes. Thus, it is desirable that the mixed layer ion exchange hydrogel forming polymer compositions of the present invention have a high PUP capacity for a measurement time of about 225 minutes, preferably for a measuring time of about 60 minutes, even more preferably for a measurement time of approximately 5 minutes. A method for determining the PUP capacity value of the hydrogel-forming polymer is provided below in the Test Methods Section. (2) Porosity of the Hydrogel Zone or Layer Another important feature of the mixed layer ion exchange hydrogel forming abeebentee polymers, useful in the present invention is the opening or porosity of the hydrogel zone or layer formed when the polymers by body fluids under a confining pressure. It is believed that when the hydrogel-forming absorbent polymers are present at high concentrations within an aromatic member and then swell to form a hydrogel under use pre-conditions. The limits of the hydrogel come into contact, and the interstitial spaces in this region of high concentration are generally joined by the hydrogel. When this occurs, it is believed that the opening or porosity properties of this region are generally reflective of the porosity of the hydrogel zone or layer formed from only the hydrogel-forming absorbent polymer. As used herein, the term "porosity" means a volume of fraction (smaller dimension), which is not occupied by the solid material. Véaee J.M. Coulson et al., Chemical Engineering Volume 2, 3rd edition Pergamon Prese, 1978, P126. For a zone or layer of hydrogel formed entirely from a hydrogei-forming absorbent polymer, porosity is a fractional volume of the zone / layer that is not occupied by the hydrogel. For a region of an absorbent member containing the hydrogel, ae as other component, the poroeity of the fractional volume of the region (also referred to as void volume, which includes the interstitial volume between the swollen hydrogel-forming polymer plus any volume within hydrogel-forming swollen polymer (ie, integral porosity)), which is not occupied by hydrogel or other solid components (eg fibers). The porosity of an absorbing region is equal to the ratio of the hollow volume within the region with respect to the total volume of the region.

The porosity is defined herein in terms of the porosity value of the hydrogel layer PHL of the hydrogel-forming absorbent polymer. The PHL measures the faculty of the hydrogel zone or layer formed to remain open to be able to acquire and distribute the body fluids under preemption of ueo. It is further believed that the increase in poroeity of these high-concentration, swollen regions, at higher levels can provide averaging properties and fluid handling for the absorbent member and the absorbent core, thereby reducing leakage incidents, especially in high fluid loads. Desirably, the hollow volume per gram contained by the gaps within the zone. or. hydrogel layer. it approximates or even exceeds the hollow volume by gram »contained within conventional acquisition / dielectric materials such as the wood pulp pellet. (The value of higher PUPs are also a reflection of the capacity of the hydrogel formed to acquire bodily fluids under normal conditions). The poroeity of the hydrogel zone or layer is also important because of its impact on the demand for wettability or gravimetric absorbency (ie, PUP capacity). Generally, the additional hollow volume generated by a higher porosity under a confining pressure contributes directly to a higher value for the PUP capacity. This can also contribute to a higher PUP capacity through its impact on the chemical composition of the fluid contained within the voids in the hydrogel layer. Thus, for example, an increase in the void volume within the hydrogel layer can reduce the concentration of salts (ie, by diluting), including the originating eelae of the body fluids and / or the hydrogel-forming absorbent polymer. , as well as the polymer salts (for example, the extractable polymer, which originate from the hydrogel-forming polymer), which have to be excluded from the swollen hydrogel-forming absorbent polymer and concentrated in the voids, zone or hydrogel layer. The concentrated salts within these voids can reduce the swelling of the hydrogel-forming absorbent polymer and thus reduce the PUP capacity. The increased poroeity can reduce the concentration of eetae ealee excluidae and therefore increase the capacity of PUP. The poroeity or hydrogel zone is also important due to its impact on the permeability (ie, the SFC values) of the hydrogel zone / layer. Superior porosity is an important contributor to superior permeability. Conversely, a hydrogel zone or layer with a relatively low porosity is less likely to have very high permeability. The porosity of the zone or layer of hydrogei may also be important as a result of its impact on the properties of capillary action or wicking effect. The high specific surface area required for a hydrogel layer or zone capable of good capillary action properties (ie, the capillary action of the fluid at a high altitude, starting from the fluid away from a cofacial acquisition layer, etc.) is desirably accompanied by high porosity to achieve or maintain an acceptably fast capillary action coefficient. The porosity or zone or layer of hydrogel can also be important as a result of its impact on the properties of the swelling coefficient. The high surface area (eg, the internal surface area), required for an unrestrained hydrogel-forming absorbent polymer that rapidly swells in body fluids, is desirably accompanied by high porosity (including internal porosity for the forming polymers). hydrogel having internal surface area), within the zone or layer of hydrogel formed therefrom, under a confining pressure. Desirably, as a result of this higher porosity, the swelling coefficient realized under the confining pressure for the hydrogel-forming polymers within the hydrogel layer approximates the swelling coefficient made by the hydrogel forming polymer when it swells without restriction in an excess of body fluid. The increased osmotic conduction force for the swelling of an ion exchange hydrogel-forming polymer of mixed stratum can also be used to increase the PHL value. Thus, for example, the level of crosslinking preferably, the level of crosslinking of the surface of the anionic and / or cationic constituents forming hydrogel in a mixed strand ion exchange hydrogel-forming polymer composition can be increased in a sufficient such that the PHL capacity of the mixed stratum composition remains approximately equal to a comparable mixture of the anionic and cationic hydrogel-forming polymers, in their neutralized forms, where the level of cross-linking has not been increased. For example, as a result of the increase in crosslinking, the mixed strand exchange hydrogel-forming polymer composition may have an approximately equal PUP value, but a PHL value higher than that of the comparable mixture of the hydrogel-forming anionic and cationic polymere, in neutralized form, where the level of cross-linking has not increased. The PHL value of the mixed layer ion exchange hydrogel-forming absorbent polymers useful in the present invention is preferably increased by at least about 0.05, more preferably at least about 0.1 relative to a comparable mixture of the anionic polymere and cationic constituent of hydrogel formed in neutralized form where the level of crosslinking is such that the neutralized mixture has an absorption capacity of PUP (0.7 pei)., 225 minutes of tranecurrido time), approximately equal to that of the ion exchange mixture.

The mixed strand ion exchange hydrogel-forming absorbent polymers useful in the present invention preferably have PHL values of at least about 0.15, more preferably at least about 0.18, still more preferably at least 0.20, and most preferably The method of determining the PHL value of hydrophilic polymer-forming eetos ee is provided below in the Test Methods section. (3). Saline Flow Conductivity (SFC). . Another important characteristic of the absorbent polymers forming and mixing hydrogel, of mixed stratum, useful in the present invention is any of the permeability or flow conductivity when they swell with body fluids to form a hydrogel zone or layer. This permeability or flow conductivity is defined herein in terms of the value of the salt flow conductivity (SFC) of the hydrogel-absorbing absorbent polymers. The SFC measures the faculty of the zone or layer of hydrogel formed to transport or distribute bodily fluids under pressures of use. It is believed that when hydrogel-forming absorbent polymers are present at high concentrations within an absorbent member and then swell to form a hydrogel under pressure, the properties of permeability or flow conductivity are generally reflective of the permeability or conductivity properties of the hydrogel. flow of a hydrogel zone or layer formed from only the hydrogel-forming polymer. It is further believed that the increase in the permeability of the swollen regions of high concentrations at approaching or exceeding levels exceeds the conventional acquisition / dielectric material, such as wood pulp fluff, can provide superior fluid handling properties for the absorbent member and the absorbent core. In this way, reducing leakage incidents, especially in high fluid loads. (The evaluation of SFC euperiorea also reflects the capacity of the hydrogel formed to acquire body fluids under normal conditions of use). It is also possible to increase the increased osmotic conduction force for the swelling of an ion exchange hydrogel-forming polymer, of mixed stratum to increase the PUP value, therefore, for example, the level of crosslinking, preferably the level of Surface crosslinking of the hydrogel forming anionic and / or cationic polymer constituents in an ion exchange hydrogel-forming polymer composition of mixed stratum can be increased sufficiently such that the PUP capacity of the composition of mixed stratum remains approximate equal to a comparable mixture of hydrogel-forming anionic and cationic polymers, in their neutralized forms, where the level of cross-linking has not increased. For example, as a result of the increase in crosslinking, the mixed layer ion exchange hydrogel formation composition may have an approximately equal PUP value, but a higher SFC value than that of the comparable mixture of polymers. anionic and cationic hydrogel formers, in neutralized forms, where the level of crosslinking has not increased. The SFC value of the mixed strand ion exchange hydrogel-forming absorbent polymers useful in the present invention is preferably increased by at least about 50%, more preferably at least about 100%, relative to a comparable mixture of the anionic and cationic polymers constituents of hydrogel in their neutralized forms where the levels of crosslinking are such that the neutralized mixture has a PUP capacity of abevorción (0.7 psi, 225 minutes of elapsed time), approximately equal to that of the mixture of ion exchange.

The SFC value of the mixed strand ion exchange hydrogel forming builders and polymers useful in the present invention is preferably at least about 30 x 10"7 cm3 sec / g, more preferably at least about 100 x 10". 7 cm3 sec / g, more preferably at least about 300 x 10"7 cm3 sec / g A method for determining the SFC value of these hydrogel-forming absorbent polymers is provided below in the Test Method section. (4). Removable Polymer Another important feature of the anionic and cationic ion exchange-forming hydrogel forming polymers used in the present invention is the level of extractable polymer material present therein after neutralization. See U.S. Patent No. 4,654,039 (Brandt et al.), Issued March 31, 1987 (reissued on April 19, 1988 as Re. 32,649). Many of the hydrogel-forming absorbent polymers contain significant levels of extractable polymer material. This extractable polymer material can be lixidized from the resulting hydrogel by body fluids (eg, urine), during the period of time such that body fluids remain in contact with the absorbent hydrogel-forming polymer. It is believed that the extracted polymer material can alter both the chemical characteristics (e.g., "osmorality") and the physical characteristics (e.g., viscosity) of the body fluid to such an extent that the fluid is absorbed more slowly and maintained poorly by the body. Hydrogel This polymer contaminated fluid is also more poorly transported through the absorbent member.This situation may contribute to the undesirable and premature leaks or drainage of the body fluid from the absorbent article.Therefore, it is desirable to use hydrogel-forming absorbent polymers. with lower levels of extractable polymer material The importance of not adversely impacting the effectiveness of the absorption / retention of the corporeal fluid by the hydrogel-forming, swelling polymer, or the ease of transport of the body fluid through the regions of the absorbent member containing pol swollen number, it is believed to be truly real as: (a) the amount of the polymer in the absorbent member is increased; (b) the amounts of other absorbent components (eg fiber) are decreased; and / or (c) the localized concentration of the polymer in the absorbent member is increased. Thus, for example, it is believed that at higher localized concentrations of the hydrogel forming polymer in the builder member, it exits a smaller volume of fluid within the interstitial regions (i.e., outside the hydrogel), which dilute to the removable polymer thus tending to increase its concentration in these interstitial regions. This exacerbates the effect of extractable polymer in the corporeal fluids produced within these interstitial regions. The adverse impact of ioe level of extractable polymer euperioree on the affinity / retention of the fluid by the hydrogel-forming absorbent polymer and the transport of fluid through the region intereticialee within the area or layer of hydrogel reeultante, also discernible in terms of PUP and SFC capacity values. In this way, for example, it is not common for hydrogel-forming absorbent polymers having levels of superior extractable polymer material to have a PUP capacity value that decreases over time (eg, it is reduced to 225 minutes against 60 minutes). This decrease in the absorption / retention of the fluid over time is believed to be, at least in part, a consequence of the higher extractable polymer levels that eethan preends to alter the chemical properties of the interstitial fluid. It is also not common for the hydrogel-forming polymer having higher levels of extractable polymer to have an SFC value that is initially low and then increasing a longer limit over time than a comparable hydrogel-forming polymer having a higher level. of lower removable polymer. The initial value of internal SFC for the extrapermeable polymer material is believed to result, at least in part, of a superior initial viscoeity for the interstitial fluid. Therefore, for the anionic and cationic hydrogel-forming, ion exchange-forming, absorbent polymers useful in the present invention, it is preferred that the level of! Removable polymer after neutralization at about 75% is about 15% or less, more preferably at least about 120% less and most preferably about 7% or less of the total polymer. The method for determining the level of the extractable polymer after neutralization in this polymeric anionic and cationic hydrogel formers, ion exchange absorbers is provided below in the Test Methods section. (5). Gel Volume Another feature that may be important for the anionic polymerics and cationic hydrogel-forming, ion exchange absorbers useful in the present invention is the gel volume after neutralization. As used herein, the "gel volume" of a hydrogel-forming absorbent polymer is defined as its free swelling absorbent capacity, when it swells in an excess of synthetic Jayco urine and neutralized to approximately 75%. This provides a measure of the maximum polymer capacity of the polymer under conditions of use where the polymer preemption is relatively low. The method for determining the gel volumes of the hydrogel-forming polymer is given below in the Test Methods section. It is preferred that the anionic and cationic abeorbentee ion exchange hydrogel formers have a relatively high gel volume after neutralization. This allows the polymer to absorb a larger amount of bodily fluids under conditions of use where polymer preemptione are low. It is preferred that the gel volume of the hydrogel-forming absorbent polymers of the present invention be at least about 20 g / g, more preferably at least about 25 g / g, and most preferably at least about 30 g / g. Typically, these gel volumes are in the range of about 20 to about 100 g / g, more typically from about 25 to about 80 g / g, and very typically from about 30 to about 70 g / g. (6) Gel Resistance Another feature that may be important for the anionic and cationic ion exchange hydrogel-forming cationic polymer in the present invention is the strength of the gel after neutralization. As used herein, "gel strength" is related to the tendency of the hydrogel formed from the polymer binder to deform or "flow" under stress. The re-warming of the gel needs to be such that the hydrogel does not deform and fill to an unacceptable extent the hollow spaces between the hydrogel and the other components within the absorbent member. In general, the strength of the increasing gel will result in an increase in the permeability and porosity of a zone or layer of hydrogel formed from the hydrogel forming polymer. A method for determining the re-equilibrium of the gel after the neutralization of the ionic polymeric and cationic ion exchange hydrogel-forming absorbers of the present invention is provided below in the Test Methods section. Although carrying the maximum strength of the gel is not as critical as other properties such as PHL, PUP SFC capacity, it is preferred that the ion exchange hydrogel anionic and cationic copolymer polymers of the present invention have a relatively high gel strength. elevated after neutralization. This increases the capacity of! hydrogel formed to repeat the deformation under the pressure of use. It is preferred that the gel strength after neutralization of the anionic and cationic ion exchange hydrogel-forming absorbent polymers of the present invention be at least about 10,000 dynes / cm 2, more preferably at least about 20,000 dynes / cm 2 and very preferably of at least about 40,000 dynes / cm2. c. Processing Methods The basic hydrogel-forming absorbent polymer can be formed in any conventional manner. Typical and preferred processes for producing these polymers are described in reissued US Pat. No. 32.84? (Brandt et al.), Issued April 19, 19888, United States Patent No. 4,666,983 (Tsubakmioto et otroe), issued May 19, 1987; and U.S. Patent No. 4,625,001 (Tsubakimoto et otors), issued November 25, 1986, all of which are incorporated by reference. Preferred methods for forming the basic hydrogel-forming absorbent polymer are those involving the polymerization methods of aqueous solution or other solution. As described in the above-referenced patent of the reissued Patent No. 32,649, the polymerization in aqueous solution involves the use of an aqueous reaction mixture to carry out the polymerization. The aqueous reaction mixture is then subjected to polymerization conditions which are sufficient to produce in the mixture, the polymer crosslinked slightly in the network, usually unsolvable in water. The mass of the formed polymer can then be pulverized or shredded to form individual particles. More specifically, the aqueous solution polymerization method for producing the hydrogel-forming absorbent polymer comprises preparing a reaction mixture in which the polymerization is carried out. One element of this reaction mixture is the monomer that will form the "spine" of the hydrogel-forming absorbent polymer that is produced. The reaction mixture generally • r- iP comprises about 100 parts by weight of the monomer. Other components of the aqueous reaction mixture comprise a crosslinking agent in the network. The crosslinking agents in the network useful in the formation of the hydrogel-forming absorbent polymer according to the present invention are described in more detail in the previously referenced United States patent reissue No. 32,649, United States Patent No. 4,666,983, and United States Patent No. 4,625,001. The crosslinking agent in the network will generally be present in the aqueous reaction mixture in an amount of about 0.01 mol percent to about 5 mol% in the total moles of the monomer present in the aqueous mixture (from about 0.01 to about 20 parts). in weight, based in 100 parts by weight of the monomer). An optional component of the aqueous reaction mixture comprises a free radical initiator which includes, for example, talee peroxide compounds such as sodium, potassium and ammonium sulfate, caprylyl peroxide, benzoyl peroxide, hydrogen peroxide, eumeno hydroperoxide , terbutyl diperttaphthalate, terbutyl perbenzoate, sodium peracetate, sodium percarbonate and eimilaree. Others Optional components of the aqueous reaction mixture comprise the various comonomers, including esters of monomers containing unsaturated functional acid groups or other comonomers that do not contain carboxycidal functional or eulonic acid or amine at all. The aqueous reaction mixture is subjected to the polymerization conditions, which are sufficient to produce, in the polymer mixture, lightly networked, hydrogel-forming absorbers, substantially insoluble in water, but capable of swelling in water. The polymerization conditions are also discussed in greater detail in the three patents referenced above. Eetae polymerization conditions generally involve heating (thermal activation techniques), at a polymerization temperature of about 0o to about 100 ° C, more preferably from about 5o to about 40 ° G. the polymerization conditions under which the aqueous reaction mixture is maintained can also include, for example, subjecting the reaction mixture, or parts thereof, to any conventional form of irradiation that activates the polymerization. Radioactive, electronic, ultraviolet or electromagnetic radiation are conventional alternating polymerization techniques. Loe group funclonalee! The hydrogel forming polymer formed in the reaction reaction may be either neutralized or partially or completely neutralized. The neutralization can be carried out either before or after the polymerization in any conventional manner resulting in at least about 25 mol% and more preferably at least about 50 mol%, of the neutralization of the total monomer used to form the polymer. The hydrogel-forming anionic polymers are neutralized with a salt-forming cation. Salt-forming cations include, for example, alkali metals, ammonium, ammonium and amides as discussed in greater detail in reissued US Pat. No. 32,649, referenced above. The hydrogel-forming cationic copolymeric polymers are typically neutralized with strong monovalent acids such as HCl. For some of the polymerization reactions, it may be preferable for reasons of the reaction mechanism to polymerize the monomer in any neutralized or neutralized form, even though the product has already been neutralized or neutralized repectively. Although it is preferred that the particle versions of the hydrogel-forming absorbent polymer be manufactured using an aqueous solution polymerization process, it is also possible to carry out the polymerization process using multiphase phase polymerization processing techniques such as reverse emulsion polymerization or Polymerization procedures in reverse suspension. In reverse emulsion polymerization or reverse-melt-point polymerization processes, the aqueous reaction mixture as described above is suspended in the form tiny droplets within a matrix of an inert organic solvent, non-water-miscible, such as cyclohexane. The resulting hydrogel-forming absorbent polymer particles are generally spherical in shape. The polymerization and euspension processes are described in more detail in the patent of United States Patent No. 4,340,706 (Obayashi et al.), Issued July 20, 1982.; U.S. Patent No. 4,506,052 (Fiexher et al.), issued March 19, 1985, and U.S. Patent No. 4,735,987; issued on April 5, 1988, all of which are incorporated by reference. Surface crosslinking of the initially formed polymers is a preferred process for obtaining hydrogel-forming absorbent polymers having relatively high values of PHL, PUP and SFC capacity. The hydrogel-forming absorbent polymers that are crosslinked on the surface in general have euperioree values for PHL, PUP and SFC capacity than those having a comparable level of "functional" latices, but without surface crosslinking. Without being bound by theory, it is believed that cross-linking at the surface increases the resistance to deformation of the surface of the hydrogel forming polymer, thereby reducing the degree of contact in which neighboring surfaces of the polymer when the polymer is deformed. hydrogel resulting under external pressure. The degree to which the values of PHL, PUP and SFC capacity are increased by surface crosslinking depends on the level and relative dielectricity of the internal and surface cross-sections and the specifications of the chemistry and cross-linking process in the surface. The functional lattices are those that elastically activate and contribute to an increase in the modulus for the polymeric materials formed from swollen hydrogel. The gel volume generally provides a reasonable measure of a level of "total!" Crosslinking in a hydrogel forming polymer, assuming that only the significant variable is the level of crosslinking. Generally, the gel volume has an inverse exponential law dependence on the level of crosslinking. Additional means for determining the total levels of the functional lattices include measuring the shear and elastic shear modulus of the resulting hydrogel formed by the swollen polymer. The cross-linked hydrogel-forming absorbent polymers on the surface have a higher level of crosslinking in the vicinity of the surface than inside. As used in the preeente "euperficie" defines the limits that give out of the particle, fiber, etc. For the hydrogel-forming, porous polymer (eg, porous particles, etc.), the exposed internal limits may also be included. By a higher level of crosslinking at the surface, it is implied that the level of the functional lattices for the hydrogel-forming absorbent polymer in the vicinity of the surface is generally higher than the level of functional lattices for the polymer in the interior. The graduation in the cross-linking of the surface towards the interior can vary, both in depth and in profile. In this way, for example, the depth of the euphemian reticulation may be shallow, with a relatively sharp transition to a lower level of crosslinking. Alternatively, for example, the depth of the surface crosslinking may be a significant fraction of the dimensions of the hydrogel-forming absorbent polymer, with a wider transition. Depending on size, shape, porosity, as well as functionalization, the degree and gradient of the surface crosslinking may vary within a given hydrogel forming polymer. For the particulate hydrogel-forming polymer, surface cross-linking may vary with size, particle porosity, etc. depending on the variations in the surface: volume ratio within the hydrogel-forming absorbent polymer (e.g., between small and large particles), it is not common for the level of total cross-linking to vary within the material (e.g., be greater for the particles). minors). Surface crosslinking is generally achieved after the final limits of the hydrogel-forming absorbent polymer are essentially established (e.g., grinding, extruding, foaming, etc). However, it is also possible to perform concurrent surface crosslinking with the creation of fine boundaries. In addition, some additional changes in the boundaries may occur even after the gratings are introduced on the surface. A process number for introducing reticles into the surface is disclosed in the art. For the hydrogel-forming anionic polymers, these include those where: (I) an active or di-or polyfunctional reagent (eg, glycerol, 1,3-dioxolan-2-one, polyvalent metal ions, polyquaternary amine), capable of reacting with the functional groups extendable dentor of the hydrogel-forming abeorbent polymer ee applied to the surface of the hydrogel-forming absorbent polymer; (ii) a di- or polyfunctional reactant is applied to the surface that is capable of reacting with other reactive and functionally reactive groups that possibly exist within the hydrogel-forming absorbent polymer such as to increase the level of cross-linking on the surface ( example, the addition of more crosslinking monomer and the initiation of a second polymerization reaction); (iii) additional polyfunctional reagents are not added, but additional reaction or reactions between the existing components within the absorbent polymer forming the hydrogel is induced either during or after the primary polymerization process in such a way as to generate a higher level of crosslinking in or near the surface (e.g., heating to induce the formation of anhydrides and / or ester lattices between the hydroxyl groups and / or carboxylic acid of the existing polymer, and polymerization process in euepension where the crosslinker is inherently present at higher levels. Near the surface and (iv) other materials are added to the surface in such a way as to induce a higher level of crosslinking or otherwise reduce the deformability of the surface of the reefering hydrogel. either concurrently or can also be used. In addition to the crosslinking reagents, other components may be added to the surface to assist / control the distribution of crosslinking (eg, spreading and penetration of surface crosslinking reagents.). For hydrogel-forming cationic polymers, methods for surface crosslinking include those where (i) a di- or polyfunctional reactant (s) is applied to the surface of the hydrogel-forming absorbent polymer (e.g., di / poly-haloalkane, di- / poly-epoxides, di / acid polychlorides, di / poly-tosyl alkanes), capable of reacting with the functional groups existing within the hydrogel-forming absorbent polymer; (ii) a di- or polyfunctional reagent is applied to the surface that is capable of reacting with other added active and functional groups possibly existing within the hydrogel-forming absorbent polymer in such a manner as to increase the level of cross-linking on the surface ( example, the addition of more crosslinking monomer and the initiation of a second polymerization reaction); (Ii) additional polyfunctional reagents are not added, but additional reaction or reactions are induced between the components existing within the hydrogel-forming absorbent polymer, either during or after the primary polymerization process in such a way as to generate a level of top or near-surface crosslinking (eg, polymerization processes in the suspension where the crosslinker is inherently present at a level close to the surface); and (iv) other materials are added to the surface such as to induce a higher level of crosslinking or otherwise reduce the surface forming capacity of the resulting hydrogel. Suitable general methods for carrying out surface cross-linking of the hydrogel-forming absorbent polymers and absorbers of the present invention are disclosed in U.S. Patent No. 4,541,871 (Obayashi), issued September 17, 1985; published PCT application W092 / 16565 (Stanley), published October 1, 1992, published PCT application WO90 / 08789 (Tai), published Aug. 9, 1990; PCT application published WO93 / 05089 (Stanley), published on March 18, 1993; PCT application published 4,824,901 (Alexander), issued on April 25, 1989; U.S. Patent No. 4,789,861 (Johnson), issued January 17, 1989; U.S. Patent No. 4,857,308 (Makita), issued May 6, 1986; U.S. Patent No. 4,734,478 (Tsubakimoto), issued March 29, 1988; U.S. Patent No. 5,164,459 (Kimura et al.), issued November 17, 1992; published patent application No. 4,020,789 (Dahmen), published August 29, 1991; and published European patent application No. 509,708 (Gartner), published October 21, 1992; all of which are incorporated by reference. A hydrogel-forming absorbent polymer in the unneutralized ion exchange form can be converted to its partially neutralized form using normal neutralization procedures. For example, a stoichiometric amount of NaOH or HCl may be added in aqueous solution, which is sufficient for partial neutralization at, for example, about 75%, for an anionic or cationic hydrogel-forming polymer not subsequently neutralized, followed or processed to remove the water added. In a similar manner, a hydrogel forming polymer in the neutralized form can be converted to its non-neutralized ion exchange form using ethanal procedures. For example, a light stequeometric excess of HCl or NaOH in aqueous solution can be added, respectively, to an aqueous solution of partially neutralized cationic anionic hydrogel-forming polymer, followed by exchange with solvent to remove excess reagents and water, followed by Eecado to remove residual eelentee. For surface cross-linked hydrogel-forming polymers, these conversion methods can typically be carried out either before or after surface cross-linking. For hydrogel-forming polymers where the cross-links on the surface are particularly senesceable at pH or exposure to solutions of excess water and / or solvent, it may be preferable to implement any of the necessary conversion procedures prior to surface cross-linking. The particles of the hydrogel-forming absorbent polymer prepared according to the present invention are typically dried in a conventional manner. The term "eecas" is substantially used herein to mean that the particles have a fluid content, typically water or other solution content, of less than about 50%, preferably less than about 20%, more preferably less of about 10%, by weight of the particles. In general, the fluid content of the hydrogel-forming polymer particles is in the range of about 0.01% to about 5% by weight of the particles. The individual particles can be dried by any conventional method such as by heating. Alternatively, when the particles are formed using an aqueous reaction mixture, the water in the reaction mixture can be removed by asiotropic deethylation. The aqueous polymer-containing reaction mixture can also be treated with a dehydrating solvent such as methanol. You can also use combinations of this and other processing procedures. The dehydrated polymer mae can then be pulverized or shredded to form substantially dry particles of the hydrogel-forming absorbent polymer. d. Specific examples Example 1 Preparation of Neutralized Hydrogel Forming Polymers and Ion Exchange. A cross-linked, partially neutralized, anionic, sodium polyacrylic acid polyacrylic hydrogel forming polymer with a relatively high value for PUP capacity (0.7 psi, 60 minutes) is obtained from Chemdal Corporation of Palanine, Illinois (ASAP 2300; Lot No. 426152). The sample is sieved with a US mesh screen of Standard Series 50 to remove particles that are larger than approximately 300 microns in diameter (sample 1-1). It is converted into approximately 50 grams of the hydrogel-forming polymer made to the acid form by extracting the polymer in approximately 900 ml of deionized and deeionized water containing 46.5 grams of HCi (Baker, 36.5-38% HCl) concentrated. After the suspension, it was stirred for about 1.5 hours, the hydrogel forming polymer is allowed to settle and the oil is removed. eobrenadanie by decaníación. The canner solution is replaced by additional deionized and deionized water, the euepeneion was added for an additional 30 minutes, the hydrogel forming polymer is allowed to settle, and the solvent was removed by decantation. This is repeated exchange (approximately 8 days), until the pH value for the supernatant reaches between 5 and 6. After the supernatant is decanted, the hydrated hydrogel-forming polymer is subsequently immersed 3 times with sodium propane. (VWR, reactive grade), tree times with aceilone (VWR, reactive grade), and once with anhydrous ether (EM science, reactive grade). The product is attached to a sheet of feflon and allowed to dry overnight. After gently separating manually with an eepula, the product is freeze-dried for approximately 96 hours to remove any residual solvents. After moving through a 20 mesh screen of the United States, approximately 30 grams of the ion exchange hydrogel-forming polymer of polyacrylic acid, anionic acid form (sample 1-2) is obtained. A hydrolyzed, re-cycled, partially reiculated N, N-dimethylaminoethylmethacrylate-HCl hydrogel polymer is prepared using the following procedure. A one-liter potted resin pot is equipped with a mechanical stirrer, an inmer- sion thermometer, a cold gas dispersion tube to be sprayed with nilrogen, a condenser and a recirculating water bath to control the im- age. In a separate beaker, 45.0 g of dimethylaminoefilmeiacrylate (DMAEM, Aldrich 98%) are added to approximately 40 milliliters of deionized and deionized water and cooled in an ice bath. In a separate beaker, 24 ml of concentrated HCl are added to approximately 40 ml of desiccated and deionized water and cooled in an ice bath. The HCl solution was added to the DMAEM solution to convert the monomer to the HCl salt. The neutralized monomer solution is transferred to the resin pot, which is maintained at T = 22 ° C. In a flask, 0.62 g of N, N-methylenebisacrylamide crosslinker (Baker, grade of elecrophoresis) was dissolved in a small amount of deionized and deeionized water; the eeolution is then added to the pot of reein. The solution was purified with nitrogen for approximately one hour while it was agitated. In a flask, 0.010 g of poiaeium persulfation (Aldrich, 99 +%) and 0.014 g of sodium meiabieulphile (Aldrich, 97 +%) of initiators are dissolved in small amounts of deionized and deeionized water. The total water content is 90 ml. The gas diffusion pipe is elevated above the level of the solution, the speed of agitation is increased sufficiently to generate a light apex, and the solutions of potassium persulfate and sodium metabisulfyl are sequentially added in a drip manner. for a period of approximately 5 minutes. After about 35 minutes, the vertex disappears and a slight increase in temperature is observed. The agitator is taken out of the solution and the impetus of the bath is increased to approximately 50 ° C and allowed to equilibrate during the night. The gel production is removed from the resin pot, rinsed in small pieces, and transferred to a pot of reef of doe lifros equipped with a condenser, Dean Siark roller, immersion mill, and mechanical agitator, containing approximately one liter of cyclohexane ( EM Science; Omnisolve). While stirring, the temperature is increased to reflux and the water is removed by azeotropic distillation. The distillation is coníinuada until the water is removed and the femperafura is increased to approximately 80 ° C. The production is filírado to remove the ciciohexano, milled with a Wiley Mill, and famizado a íravés of a iamiz of 20 mesh of USA. The finished product is dried during the night at ambient temperature under vacuum. Approximately 54 g of production of the hydrogel-forming cationic polymer of N, N-dimefilaminoelilmeíacrilaío-HCI, reliculado, partially neufralizado (sample 1-3) was obtained. Approximately 35 g of the partially neutralized product are suspended in approximately 1500 ml of deionized and deionized water to which has been added approximately 15.9 g of 50% sodium hydroxide (Baker, reactive analyzed). After the suspeneion is stirred for about 1.5 hours, the hydrogel forming polymer is allowed to settle, and the supernatant is removed by decanation. The decandered solution is replaced by additional deionized and deepened water, the suspension is stirred for an additional 30 minutes, the hydrogel forming polymer is allowed to settle, and the supernatant is removed by decanfation. The exchange process is repeated (approximately 8 times) until a pH value for the 6-7 enfrebrenadanfe reached. After the Eobrenadanie is decene, the hydroformed hydrogel-forming polymer is usually exchanged several times with isopropanol (VWR, reactive grade), fres vecee with aceine (VWR, reactive grade), and twice with anhydrous ether (EM Science, reactive grade). . The product is transferred to a Teflon sheet and allowed to dry overnight. After mixing with a mortar and pestle, the product is freeze-free for 96 hours to remove any residual solvents. After licking through the US 20-mesh lamiz, about 22 grams of the N, N-dimethylaminoethylmethacrylate ion exchange hydrogel-forming cationic polymer is obtained in baee form (1-4 moletra). The moisture content of ioe polymer formed from ion exchange hydrogenation and previously neutralized is determined by the loss of pee after 3 hours at 105 ° C. The PUP capacity is determined under confining pressures from 0.3 psi to 0.7 psi during periods of 60 minutes to 225 minutes. The exirability for the acid form of the anionic hydrophilic forming polymer and the base form of the hydrogel-forming cationic polymer is determined by following the in-situ neutralization with a standard ionization of 1 N NaOH (analyzed Baker) and 1 N HCl. (analyzed Baker), reepecíivamenfe. The volumes of the gel, the acid-forming hydrogel-forming anionic polymer and the alkali-forming hydrogel-forming polymer are deamined in the polymers such as sphene and in the polymers following the in-sifu neu- lization with a 1-NaOH standard. (analyzed Baker) and 1 N HCl (analyzed Baker), reepeclivamenle. The gel volume obtained for the ion exchange hydrogel-forming polymers without neurallization with the in-sifu neufralization was also evaluated, corrected "to a neutralized base" for comparison with the gel volumes measured for the hydrogel-forming polymers. neulralized comparable. The returns from these countries (expired on a dry weight basis) are included in Table 1-1 and 1-2. Baeadoe in the comparison of the value of the gel volume for the mueefra 1-1 and the value of the volume of gel adjusted in weight for the sample 1-2 followed by the nebulization in-silu, ee concludes that the confection of the anionic polymer forming the Hydrogel from its neural form to its acid form results in little change in the properties of the hydrogel-forming polymer eubyacenfee. From eeta way, except for the neutralization degree of lae mueetrae 1-1 and 1-2 eon materialee comparablee. Also, in a comparison of the gel volume value for sample 1-3 and the gel volume value adjusted by weight for sample 1-4 following in-vitro neutralization, it is concluded that the conversion of the hydrogel-forming cationic polymer from its neutralized form to its base form results in little change in the eubyacenlee property of the hydrogel-forming polymer. Therefore, except for the degree of nebulization, the samples 1-3 and 1-4 are comparable materials.

TABLE 1-1: Properties of the samples of Example 1 Sample Moisture Polymer Gel Volume (% by weight) (fl / q) Removable (% weight) 1-1 (Anionic: neutralized form) 5.5 42.6 7.2 1-2 (Anionic: acid form) 4.7 5.7 (a) 1.1 1-3 (Cationic: neutralized form) 1.3 15.4 < 5 1-4 (Cationic: acid form) 0.5 6.0 (b) < 5 a) The gel volume is 53.9 g / g followed by approximately 75% of the in-situ neutralization. This corresponds to a value adjusted in weight of approximately 44 g / g. b) The gel volume is 16.3 g / g followed by approximately 100% neutralization n-situ. This corresponds to a value adjusted in weight of approximately 13 g / g.

TABLE 1-2: Values of the PUP Capacity of the samples of Example Kb) Sample 0.3 psi 0.3 psi 0.7 psi 0.7 psi (60 minutes) (225 minutes) (60 minutes) (225 minutes) 1-1 (Anionic: neutralized form) 38.2 (a) 31.9 (a) 1-2 (Anionic: acid form) 8.2 (a) 6.9 (a) 1-3 (Cationic: neutralized form) 11.1 14.9 10.2 13.7 1-4 (Cationic: acid form) 5.5 6.0 5.4 5.8 a) The value of the PUP capacity in 225 minutes for this sample is approximately equal to its value in 60 minutes. b) All values are corrected for humidity and are expressed in units of g / g.

EXAMPLE 2 PUP Capacities for Mixed Stratus Ionic Exchange Hydrogel Formation Polymer Compositions The corrected moisture cation exchange capacity of the polyacrylic acid hydrogel-forming polymer is estimated to be about 13.9 meq / g, based on its molecular weight of the monomer. The moisture-corrected anion exchange capacity of the polydimethylaminoelylmethylacryl hydrogel-forming polymer is estimated to be about 6.4 meq / g, based on its molecular weight. monomer Based on these values for cation exchange or anion exchange capacities, a mixed ion exchange composition containing polyacrylic acid and polydimethylaminoelyl methacrylate hydrogel forming polymers, which have approximately equal equivalents of cation exchange capacity and anion exchange, have a weight ratio of anionic polymer: cationic of approximately 0.31: 0.69 and has an anion exchange capacity of mixed ratio of approximately 4.4 meq / g. - The ion exchange hydrogel-forming polymer compositions with a total weight of about 0.9 grams and a weight ratio of 0.31 parts of the sample 1-2 to 0.69 parts of the 1-4 ee mole prepared by mixing aliquots of doe molars (sample 2-1). After mixing, the ion exchange hydrogel forming compositions are transferred to a PUP cylinder for the measurement of PUP capacity. The comparable 0.31: 0.69 weight ratio blends of samples 1-1 and 1-3, where the anionic and cationic hydrogel-forming polymers are in neutralised forms, are also prepared by mixing aliquots of the two samples (sample 2- 2). After mixing, this comparable mixture of neutralized hydrogel-forming polymers is transferred to a PUP cylinder for the measurement of P * UP capacity. The PUP capacity values are determined for confinement presses of 0.3, 0.7 and 1.4 pei and measurement times of 60 minutuses and 225 minutes. The value corrected for moisture measured for the PUP capacity is given in Table 2-1. A comparison of PUP capacity values at 225 minutes demonstrates that the composition of ion exchange hydrogel-forming polymer exhibits more than 50% increase in PUP capacity at confining pressures of 0.7 psi and 1.4 pei with a comparable mixture of hydrogel-forming anionic and cationic polymers, each in its neutralised forms. The increase in PUP capacity at a confining pressure of 0 3 pei ss greater than 40%.

TABLE 2-1. PUP Capacity Values for Compositions Mixed Stratum Ion Exchange Sample 0.3 psi? 3 psi 0.7 psi 0.7 psi 1.4 psi 1.4 psi (60 min) (225 min) (60 min) (225 min) (60 min) (225 min) 2-1 25.0 32.8 19.0 29.7 15.1 22.4 2-2 22.8 23.1 17.8 19.2 9.5 13.9 2. Fibrous Materials The absorbent members of the present invention may comprise fibrous materials to form fibrous webs or fibrous matrices. Lae fibrae útilee in the present invention include those which are naturally occurring fibers (modified or unmodified), as well as elastically produced fibers. Examples of fibers naturally occurring and modified or modified, include cotton, esparto grass, bagasse, kemp, flax, silk, wool, wood pulp, chemically modified wood pulp, jute, rayon, ethyl cellulose and cellulose acetate. Suitable etyelic fibers can be made of polyvinyl chloride, polyvinyl fluoride, polytetrafluoroethylene, polyvidylidene chloride, polyacrylics such as ORLON®, polyvinyl acetyl, polyethylene vinyl keratin, soluble or insoluble polyvinyl alcohol, polyolefins such as polyethylene (e.g. PULPEX®) and polypropylene, polyamides such as nylon, polyesteree talee like DACRON® or KODEL®, polyurethane, polyeelirenoe and eimilares. The fibers used may comprise only naturally occurring fibers, synthetic fibers only or any compatible combination of natural and synthetic fibers. The fibers used in the present invention can be hydrophilic, hydrophilic, or can be a combination of both hydrophilic and hydrophobic fibers. As used herein, the term "hydrophilic" describes fibers, or surfaces of the fibers that are wettable by aqueous fluids, (eg, aqueous body fluids), deposited on such fibers. The hydrophilic capacity and wetness of individual fibers is typically defined in terms of the contact angle and surface tension of the fluids and solids involved. This is discussed in detail in the American Chemical Society publication entitled Angle of Contact, Moisture and Adhesion, edited by Robert F. Gould (Copyright 1964). A fiber, or the surface of a fiber, is said to be wetted by a fluid (ie, hydrophilic), when either the contact angle between the fluid and the fiber, or its surface is less than 90 °, or when the Fluid tends to spontaneously disperse through the surface of the fiber, both conditions coexisting normally. Conversely, a fiber or surface is considered to be hydrophobic if the angle of the count is greater than 90 ° and the fluid is not spread spontaneously across the surface of the fiber.

The particular selection of hydrophilic or hydrophobic fibers will depend on the property of fluid handling and other characteristic features for the resulting absorbent member. For example, for absorbent members that are to be used to completely or partially replace a non-woven, hydrophobic sheet, at least one of the absorbent members, typically the member adjacent to the absorbent article user, may desirably comprise hydrophobic fibers. . The hydrophobic fiber yarn in at least one of the absorbent members may also be useful where the member comprising the hydrophobic fibers is adjacent to a "breathable" but somewhat permeable fluid back sheet of an absorbent article such as an absorbent article. training pants for babies; the member comprising the hydrophobic fibers provides a barrier impermeable to the fluid. For many absorbent members according to the present invention, the use of hydrophobic fibers is preferred. This is especially true for the member who wants to efficiently acquire the discharged body fluids, and then quickly transfer and distribute the acquired fluid to other regions remote from the abeorbenite member or apobulent core. The use of hydrophilic fibers is particularly desirable for those absorbent members comprising the hydrogel-forming absorbent polymers. Hydrophilic fibers for use in the present invention include cellulosic fibers, modified cellulose fibers, rayon, polyether talee fiber such as polyethylene terephthalate (for example DACRON®), hydrophilic nylon (HYDROFIL®), and the like. Suitable hydrophilic fibers can also be obtained by hydrophilizing the hydrophobic fibers, such as the irramoplasic fibers sprayed with fibrous agent or frayed with silica, derived from, for example, polyolefin such as polyethylene or polypropylene, polyacrylics, pollamidae, polystyrenes, polyurethanes and the like. For reasons of availability and cost, cellulosic fibers are preferred, in particular wood pulp fibers for use in the present invention. Suitable wood pulp fibers can be obtained from well-known chemical processes such as the Kraft and sulfite processes. It is especially preferred that this is derived from wood pulp fiber and euavee wood from the Eur, due to its excellent nature characteristics. The fibers of wood pulp can also be obtained from mechanical processes such as wood logs at the level of dust, refined mechanical pulp, mechanical-mechanical-chemical and chemical-lermomechanical processes. Lae fiber from recycled or secondary wood pulp as well as bleached and unbleached wood pulp fibers can be used. A desirable source of hydrophilic fibers for use in the present invention is the chemically hardened cellulosic fibers. As used herein, the term "chemically hardened cellulosic fiber" means cellulosic fibers that have been hardened by chemical means to increase inflexibility under ambae condicionee in eeco and acuoeae. This medium may include the addition of a chemical curing agent, for example, coated and / or impregnated in the fiber. These means may also include the hardening of the fibers by altering the chemical structure, for example, by recycling the polymer chain. Polymeric curing agents that can coat or impregnate cellulosic fibers include: modified cationic starches having nitrogen-containing groups (eg, amino groups) such as those available from National Starch and Chemical Corp., Bridewaier, NJ. USA; láíex; wet lamination resin such as polyamide-epichlorohydrin reine (for example, Kymene 557H, Hercules, Inc., Wilmingfon, Delaware, USA), polyacrylamide resins described, for example, in United States Patent No. 3,556,932 ( Coscia and ofroe), issued on January 19, 1971; the commercially available polyacrylamides sold by American Cyanamid Co., Siamford, CT, USA, under the trade name Parez 631 NC; the urea formaldehyde and melamine formaldehyde resin, and polyethyleneimine lae reeine. A general discussion on wet strength tests used in the paper technique, and the general application here, can be found in the TAPPI monograph series No. 29. "Weí Sfreng ¡n Paper and Paperboard", technical association of the industry of pulp and paper (New York, 1965). These fibers can also be hardened by chemical reaction. For example, the re-linking agents can be applied to the fibers which, after In the application, they are made to form chemically inírafibra reticulum bonds. These linkages can increase the inflexibility of the fibers. Although the use of infrafiber relic linkages to chemically harden fiber is preferred, it is not implied to exclude other types of reacts for chemical hardening of the fibers. The fibers hardened by the reticule bonds in an individualized way (i.e., individualized hardened fibers are taken as well as the processes for their preparation) are disclosed, for example, in United States Patent No. 3,224,926 (Bernardin) issued December 21, 1965, a Patent of US Pat. United States No. 3,440,135 (Chung), issued April 22, 1969; U.S. Patent No. 3,932,209 (Chalierjee), issued January 13, 1976; and the Patent of the 0 United States Nos. 4,035,147 (Sangenis and ofroe), issued December 19, 1989; U.S. Patent No. 4,898,642 (Moore and ofroe) issued February 6, 1990; and US Pat. No. 5,137,537 (Herron et al.), issued August 11, 1992. In the preferred hardened fibers, the chemical process 5 includes crosslinking between the fibers with relict agents while the fibers are in an effective state. relatively dehydrated condition, defibrated (for example, individualized), igneous, curly. Chemical hardening agents are typically monomeric re-linking agents that include, but are not limited to, C2-C8 dialdehyde, C2-C8 monoaldehyde having an acid functionality, and especially C2-C9 polycarboxylic acids. Several compounds are capable of reacting with at least two hydroxyl groups on a single cellulose chain or near celluloid chains located on an individual fiber. Specific examples of these re-linking agents include, but are not limited to, glutaraldehyde, glyoxal, formaldehyde, glyoxylic acid, oxydisuccinic acid and citric acid. The effect of the crosslinking under these conditions is to form fiber that is hardened and begin to laugh in its configuration. - 1Q twisted, crimped, during use in thermally bonded absorbent structures of the present. These fibers, and the processes for making them, are described in the previously incorporated patents. Such hardened fibers, which are denoted and curled, can be quantified by referencing both, a fiber "fiber count" and a "curl factor" of the fiber.

As it is here, the term "coneía de loreión" refers to the number of torsion knots present in a certain length of fiber. The torque is used as a means to measure the degree to which the fiber is rotated around its long axis. The term "torsional knot" refers sub- sequentially to an axial rofation of 180 ° around the longitudinal axis of the fiber, where a portion of the fiber (eg, the "knot") appears dark relative to the remainder of the fiber when viewed under the microscope with lransmilide light. The iris knot appears dark at locations where the traneled light travels through an additional fiber wall due to the above-mentioned airing. The difference between the knots corresponds to an axial rotation of 180 °. The number of foreground knots in a certain length of fiber (for example, the count of torsion) is indicatively indicative of the degree of toreión of the fiber, which is a physical parameter of the fiber. The procedures to determine the torsion knot and the torsion count tola! they are described in U.S. Pat. No. 4,898,642. The preferred hardened fibers will have an average dry fiber twist pattern of at least about 2.7, preferably about 4.5 toreion, knot per milliliter. In addition, the average wet fiber twist pattern of these fibers is preferably at least about 1.8, preferably at around 3.0, and should also preferably be at least about 0.5 knots of torque per millimeter less than the bill. of average dry fiber twist. Even more preferably, the average dry fiber torque must be at least about 5.5 knots per hole, and the average torsion fiber count must be at least 4.0 knots per millimeter and must also be at least 10 knots per millimeter. eer de al menoe 1.0 knot of ionion per millimeter less than your average dry fiber torsion count. More preferably, the average fiber torque twist count should be at least about 6.5 knots of torque per millimeter, and the average wet fiber twist count should be at least about 5.0 knots per millimeter and it must also be at least 1.0 knots of torque per milliliter less than average dry fiber torque. In addition to being twisted, these preferred hardened fibers are also crimped. The curl of the fiber can be described as the fractional shortening of the fiber due to the curls, twists and / or curvature in the fiber. For the purposes of the invention, the fiber curl is measured in terms of a two-dimensional plane. The exigency of the curling fiber can be quantified by reference to a fiber curl factor. The fiber curl factor, a two-dimensional measure of the curl, is determined by obeying the fiber in a plane of dimeneions. To determine the curl factor, both of the projected length of the fiber are measured as the longest dimension of a rectangle of two dimensions that surrounds the fiber, LR, and the current length of the fiber, LA. Then, the fiber curl factor can be calculated by the following equation: Facíor de Rizo = (LA / LR) - 1.

An image analysis method that can be used to measure LR and LA is described in U.S. Patent No. 4,898,642. Preferably, the hardened fibers will have a curl factor of at least about 0.30 and more preferably will have a curl factor of at least about 0.50. These chemically-hardened cellulosic fibers have certain properties that make them particularly useful in certain absorbent members according to the present invention, relative to uncured cellulosic fibers. In addition to being hydrophilic, these hardened fibers have unique combinations of hardness and resilience. This allows thermally bonded structures to be made with these fibers to maintain high levels of visibility, and exhibit high levels of resilience and a re-rise to expansion upon wetting. In particular, the resilience of hardened fibers allows the absorbent member to better maintain its capillary structure in the presence of both fluid and compression forces normally encountered during use and is thus more resistant to collapse. 3. Thermoplastic Materials In the case of the member and the fermically bound absorbers according to the present invention, the member may comprise thermoplastic material in addition to the fibers. When melting, at least part of this thermoplastic material migrates to the intersections of the fibers, typically due to the capillary gradients of the inner fiber. These intersections are made in union silioe for the thermoplastic material.

When cooled, the thermoplastic materials at these intersections solidify to form the binding sites that maintain the mastic or the fiber of juniper fibers in each of the respective layers. In view of its various effects, the union of these fiber structures increases the total bonding modulus and the resistance of the thermally bonded member. In the case of chemically bound cellulosic fibers, the fusion and migration of the thermoplastic material also has the effect of increasing the average pore size of the fabric, while maintaining the density and basis weight of the fabric as it was originally formed. This can improve the fluid acquisition properties of! thermally bonded member when initial discharges occur, due to improved fluid permeability, and as the charge increases, due to the combined ability of the hardened fibers to retain their rigidity when wet and the ability of the fermoplastic material to remain attached in the fiber inlerection of fiber when wet and when compressed in the wet. In the network, the thermally bonded fibers of hardened fibers retain their original lolal volume, but with the volumetric regions previously occupied by the iron-plating material that eventually opens to increase the average capillary pore size between the fibers. The thermoplastic materials useful in the present invention may be in any of a variety of shapes including particles, fibers or combinations of fibers and particles. Fermoplastic fibers are a particularly preferred form because of their ability to form numerous binding fibers between the fibers. Suitable thermoplastic materials may be made from any thermoplastic polymer that can be melted at temperafurae which will not extensively damage the fibers comprising the primary matrix or maize of each layer. Preferably, the melting point of this erymoplastic material will be less than about 190 ° C, and preferably about 75 ° C and about 175 ° C. In any event, the melting point of this thermoplastic material should not be lower than the temperature at which the thermally bonded aromatic substances, when used in absorbent articles, are probably stored. The melting point of the fermoplastic material is typically not less than about 50 ° C. The lemnoplastic materials, and in particular the thermoplastic fibers, can be made from a variety of thermoplastic polymers, including polyolefin, such as polyielylene (eg, PULPEX®) and polypropylene, polyesters, copolyesters, polyvinyl acetate, polyethyl vinyl acetate, polyvinyl chloride , polyvinylidene chloride, polyurea, polyamides, co-polyamides. polyesíirenoe, poliureíanos and copolymers of any of the above íal such as vinyl chloride / vinyl acetal, and the like. A preferred fermoplasic binder fiber is PLEXAFIL® polyetheylene microfibers (made by DuPont) which are also available as a blend of approximately 20% with 80% cellulosic fibers sold under the trademark KITTYHAWK® (made by Weyerhaeuser Co.). Depending on the desired characteristics for the resultant thermally bonded absorbent member, suitable thermoplastic materials include the hydrophobic fibers that have been made hydrophilic, such as the thermoplastic fibers treated with ionic acid or iris agent with silica derived from, for example, polyolefins such as polyethylene. or polypropylene, polyacrylics, polyamides, polyesíirenoe, polyurelanoe and eimilaree. The surface of the hydrophobic thermoplastic fiber can be made hydrophilic by irradiation with an ionic acid agent, such as a nonionic or anionic agent, for example, by spraying the fiber with a surfactant, by immersing the fiber within a surfactant or by include the oxidizing agent as part of the molten polymer in the production of the iron-plasma fiber. When melting and resolidifying, the active agent will tend to remain on the surfaces of the thermoplastic fiber. Suitable surfactants include nonionic surfactants such as Brij® 76 manufactured by ICI Americas, Inc. of Wilmington, Delaware, and various agents sold under the Pegosperse® brand by Glyco Chemical, Inc. of Greenwich, Connec. In addition to the non-ionic agents, the anionic agents can also be used. Eloe agents can be applied to the thermoplastic fibers at a level of, for example, about 0.2 to about 1 g / cm2 of fermoplastic fiber. The thermoplastic fibers can be made from a simple polymer (one-component fibers), or they can be made from more than one polymer (for example, two-component fibers). As used herein, "bi-component fibers" refers to thermoplastic fibers comprising a core fiber made from a polymer that is enclosed within an erymoplasmic shell made of a different polymer. The polymer comprising the shell often melts at a different, typically lower, temperature than the polymer comprising the core. As a result, this two-component fiber provides thermal bonding due to melting of the cover polymer, while providing the desired strength characteristics of the core polymer. The two-component fibers suitable for use in the present invention can include shell / core fibers which have the following polymer blends: polyethylene / polypropylene, polyvinylvinyl / polypropylene, polyvinylene / polyether, polypropylene / polyester, copolyester / polyether, and eimilar. The fermoplastic fibers of doe components are particularly suitable for use in the present area with a polypropylene or polyester core, and a co-polyester, polyethylene vinyl acetate or minor fusion polyethylene shell (eg fibers of doe componenle DANAKLON®, CELBOND). ® or CHISSO®). The fibers of the component can be concentric or eccentric. As used herein, the term "concentric" and "eccentric" refers to whether the cover has a thickness that is uniform, or non-uniform, through the cross-sectional area of the two-component fiber. The eccentric component fibers may be desirable in providing more compliant resilience at lower fiber thicknesses. The two-component fibers suitable for use here can be, either, not folded (is, say without folding) or pleated (ie, folded). The two-component fibers can be folded by means of lactic fibers such as, for example, a material box method or the mesh pleating method to achieve a predominantly two-dimensional or "flat" pleating. In the case of thermoplastic fibers, their length may vary depending on the particular melting point and you will see more properties for fiber. Typically, the thermoplastic fibers have a length of from about 0.3 to about 7.5 cm in length, preferably from about 0.4 to about 3.0 cm in length, and most preferably from about 0.6 to about 1.2 cm in length. The properties, including the melting point, of these thermoplastic fibers can also be adjusted by varying the diameter (caliber) of the fibers. The diameter of these thermoplastic fibers is typically defined in terms of either denier (grams per 9000 meters) or decitex (grams per 10,000 meters). The fibers of two suitable components can have a number on the scale from about 1.0 to about 2.0, preferably from about 1.4 to about 10, and most preferably from about 1.7 to about 3.3 The compression module of thermoplastic materials, and especially that of thermoplastic fibers, can also be important. The compression module of the thermoplastic fiber is affected not only by its length and diameter, but also by the composition and the properties of the polymer or polymers from which it is made, the shape and configuration of the fibers (e.g. , concentric or eccentric, pleated or without pleating), and similar facfores. The differences in the compression modulus of these thermoplastic fibers can be used to alter the property, and especially the density characteristics, of the respective absorbent members during the preparation of the abehorbenfe core. 4. Ofroe Componeníee y Maíerialee The additional ion exchange capacity can be increased to the abeorbenie member or to the abeorbenfe article that contains the abeorbenie member in the form of ion exchange fibers, ion exchange films, ion exchange particle resins, ion exchange coatings. on the fibers, ion exchange coatings on the film, efe. for the purpose of (i) strengthening the capacity of ionic ion exchange and / or (ii) compensating for an imbalance in the capacity of anionic exchange with cationic exchange that reflects the differences in quality, pK, effe. The aforementioned anion exchange components can also be supported by one or more of the existing components in the absorbent member or absorbent article. Thus, for example, a conventional wood pulp fiber in an abehorbenfe article can be replaced by a cationic exchange fiber. See, for example, U.S. Patent No. 4,818,598 issued to Wong on April 4, 1989, which is incorporated herein by reference. Other optional components which may be present in the absorbent webs are described in, for example, the Other Components and Materials Section of the United States Patent No. 5,562,646, issued on 8 December 1996 to Goldman and others, which it is incorporated by reference here.

C. Absorbent Members Containing Hydrogel Forming Absorbent Polymers 1. Concentration, Base Weight and Fluid Handling Properties At least one of the absorbent members according to the present invention will comprise the previously mixed mixture of the polymer and the hydrogel-formed polymer, with or without other optional components such as fiber, iron-plating material, efcélera Eloe absorbent members comprising these absorbent polymers can function as fluid storage members in the absorbent core. The main function of ßetós fluid-absorbent members is to absorb the fluid discharged from the body either directly or from other absorbent members (eg, acquisition members / fluid distribution), and then retain this fluid, including when it is eome normally encountered predictions as a result of the user's movements. It should be understood, however, that some absorbent members that contain polymer can serve several functions other than that of fluid storage. An important aspect of these absorbent members according to the present invention is that they contain one more regions having a high concentration of these hydrogel-forming absorbent polymers. In order to provide relatively high-density articles capable of absorbing and retaining large amounts of body fluids, it is desirable to increase the level of these hydrogel-forming absorbent polymers and reduce the level of other component compounds, in particular the fibrous components. In order to use these hydrogel-forming absorbent polymers in relatively high concentrations, however, it is important that such polymers have a relatively high demand absorbency capacity under a relatively high confining pressure (ie, PUP capacity value). and preferably one per relatively high city (i.e., a PHL value) as well as a relatively high permeability under pressure (i.e., the SFC value). This is the way that the polymer, when 4fc swells in the presence of the corporeal fluid, provides adequate capacity for acquiring eeloe body fluids discharged and then transporting eetoe fluids through the zone or continuous gel layer of fluid transportation to other regions of the abeorbent member and / or abeorbent nucleus and / or then storing eetoe fluid of the body. By measuring the concentration of hydrogel-forming absorbers and polymer in a given region of an absorbent member, the percentage by weight is used 1Q of the hydrogel-forming polymers relative to the combined weight of the polymers to hydrogel formers and any of the other components (for example, fibers, iron-ceramic material, elastomer) which are pre-formed in the region containing the polymer. With this in mind, the concentration of hydrogel-forming absorbent polymers in a given region of an absorbent member according to the present invention can in the range of about 60 to 100%, preferably about 70 to 100%, more preferably about 80 to 100%, and Most preferably from about 90 to 100%. Another important aspect is the basis weight of the hydrogel-forming absorbent polymers in a given region of the absorbent member. The poroeity of The hydrogel layer, the permeability of the gel and the properties of the high absorbent capacity on demand of the hydrogel-forming absorbent polymer and absorbent materials become very important in the absorbency performance of the absorbent member and the absorbent core at certain minimum base weights of the polymer. By measuring the basis weight of the hydrogel-forming absorbent polymer in a given region of an absorbent member, The pre-emulsion polymer gram is used per square meter of the area of the region. With this in mind, the basis weight of hydrogel-forming polymers in a given region of an absorbent member according to the above invention is less than about 10 g / m2, preferably at least about 20 g / m2, more preferably at less about 50 g / m2, and most preferably at least about 100 g / m2. Typically, these base weight values are in the range of from about 10 to about 1000 g / m2, typically from about 50 to about 800 g / m2, and most typically from about 100 to about 600 g / m2. When the hydrogel-forming polymer is incorporated into an absorbent storage member at a concentration and basis weight ? ft _t_μf¡ciep.temen.l high, the swelling by e! Fluid that body under pressure carries the limits of the hydrogel resudante within a given region in coníaclo (ie, the hydrogel in the regions that become contiguous). In the region of the region with high inflation / expanded concentrations, the holes and capillaries are generally joined by the hydrogel, thus forming a zone or gel layer Conveyance of fluid fluid. For this region, it is believed that the poroeity and fluid permeability is closer to that of a comparable hydrogel layer formed under pressure from the polymers only. Moreover, the use of hydrophilic preforming absorbent polymers that have relatively high PHL and preferably high CFS values confer a high degree of confidence.

Erosior porosity and preferably a permeability euperior reepeclivamenle, and thus good acquisition properties, transport and storage of fluid for the areas or gel layers of continuous fluid importation. 2. Integrity in Wetting Absorbing Member and / or Absorbing Nucleus 25 During initial fluid acquisition, the use of the absorbent core occurs in the immediate vicinity of the jet. There are several approaches to use the absorbent core beyond this initial point of fluid acquisition. The fluid can move through the top sheet and enter the core over a large area. This is not a desirable situation since this fluid is in contact with the skin and is vulnerable to lae fugae of the article abeorbenle. Certain characteristics of the article abeorbenle, for example the folds of barrier for the legs, can help with this last. Also, special fluid acquisition members have been used to move the fluid below the topsheet before cooling in the storage regions of the absorbent core. Despite eefas measures to improve the operation of fluid handling, still exerts a need for gaining lateral fluid movement (ie, X-Y dimension) as possible in the core storage regions, particularly as abeorbenfee cores become thinner and thinner. The potentials in the fluid motion of the fluid offered by the abetorbenite members comprising the relatively high poroeity and preferably the highly permeable hydrogel-forming absorbers described above require a certain amount of physical conl uency in the region containing the hydrogel (FIG. that is, the coninuous gel zone or layer of fluid transport) for the proper movement of fluid that takes place through the gaps and capillaries. The performance of the benefit of highly absorbent hydrogel absorbent polymers with high porosity and preferably high permeability is facilitated by the absorbent members and abeorbent cores designed to reduce or minimize the occurrence of separation or rupture of the conininuous gel areas or layers of fiber transport. fluid that is formed when the polymer swells by the fluid of the body. The absorbent members and / or cores that provide characiscular features are referred to herein as having good integrity in the wet. By "good integrity in the wet" it will be understood that the region or regions in the absorbent member having the high concentration of hydrogel-forming absorbent polymer have sufficient integrity in a dry, partially wet, and / or wet state than physical conininity ( and in this way the ability to acquire and to extend the fluid to flow from the configuous hollows / capillaries of the zone or continuous gel layer of fluid transport formed by inflating the hydrogel forming polymer in preemption of the body fluid. they do not break or alter ecialcially, even when subjected to normal conditions of use. During normal use, the absorbent cores in the absorbent articles are typically subjected to varying tensile and torsional strength and directional forces. These forces of tension and lore include ablation in the leg area, the forces of stretching and tearing as the person carrying the absorbent article walks, bends, flexes, and assimilates. If integrity in the wet is inadequate, these forces of tension and torsion can, in the end, cause the alteration and / or separation of the physical condition of the hydrogel in a way that degrades the ability to transport the fluids through the hollow and capillary. For example, the confined gel zone or layer may be partially separated, completely separate, have spaces inserted, have areas that are significantly thinned, and / or broken into a plurality of segrementally less significant ones. This alteration can reduce or minimize the advantageous permeability / flow conductivity and porosity properties conferred by the above-described hydrogel-forming absorbent polymer. Good wet integrity can be obtained in accordance with the present invention for several years, configurations, compositions, eicheres, the absorbent member having the high concentration of the hydrogel-forming absorbent polymer, or components in the absorbent core (e.g. the fluid acquisition members), the other components in the article abeorbenie (for example, the top sheet and / or the posirior sheet), or any combination of these components. See United States Patent No. 5,562,646, issued October 8, 1996 to Goldman et al.

^^ D. Absorbent Cores 5 The abetorbent members according to the present invention comprising high concentrations of a mixed polymer stream, and hydrogel formers useful only or in combination with other absorbent members in a variety of absorbent cores. Esloe ofroe member abeorbenfee can . 10 , include those tools to acquire the downloaded fluid initially! body before ^ that these fluids are distributed to the fluid storage member of the abetorbent core. They include acoustic members that provide multiple fluid handling properties (eg, fluid acquisition and dissipation) or individual fluid handling properties (eg, fluid dispensing). Estoe Other members may also comprise lower concentrations of hydrogel-forming absorbent polymers that have the physical properties previously - ^^ specified (eg, relatively high PUP capacity and preferably PHL and SFC values as described in B (1) (b) above) or may comprise hydrogel-forming abeorbent polymers having different physical properties (for example, PHL values, PUP capacity and / or SFC minor). A suitable absorbent core according to the present invention comprises: (1) a top assembly that holds: (a) a layer of substantially free acquisition of hydrogel-forming polymer abeorbenie; and (b) an abeorbent polymer layer comprising primarily a first polymer abeorbent The hydrogel former has an SFC value of at least about 4 x 10-7 cm 3 sec / g, more preferably at least 9 x 10-7 cm 3 eeg / g and most preferably at least 15 x 10-7 cm 3 sec. / g, and which is present in a quantity of at least 20 g / m2; and (2) a lower assembly that includes: (a) a top layer that has a hollow space for storage and redistribution of body fluids and (b) a bottom layer that contains a high concentration of a hydrogel-forming absorbent polymer. this is the same as the PUP capacity and preferably the PHL and SFC value is stated in B (1) (b) water and at least 70% of the ionic value of the hydrogel-forming absorbent polymer of mixed water. which is in the upper and lower layers is in the lower milad of the combined thickness of the upper and lower layers. An absorbent core is shown in Figure 1. Figure 1 shows a traneversal section of an absorbent article indicated as having an upper sheet 12, a back sheet 16 and an absorbent core indicated by 20 placed between the upper sheet 12 and the upper sheet 12. back sheet 16. As shown in this Figure, the core 20 comprises an upper assembly 24 and a lower assembly 28. The upper assembly 24 comprises an upper acquisition / distribution layer 32, and a layer 40 comprising the first absorbent forming polymer hydrogel separated from the acquisition layer 32 by a layer of iris 36 which has foldings in the Z direction. The lower assembly 28 comprises an upper fibrous layer 44, a lower layer 48 comprising the mixed spiral of the hydrogel-forming absorbers, and a layer of tissue 52. Layers 32 and 40 may be separate layer as shown in figure one or they may be fused in a single layer and eervir as an eneamble of storage and redistribution. As it is apparent from Figure 1, it is not essential that the layer should be coextensive. The acquisition layer 32 of the upper assembly 24 is in the effective upper layer of the absorbent core and is ecially free from the hydrogel-forming polymer abeorbenfe. If the hydrogel forming polymer is included, the quantity should be maintained relatively low and is preferably substantially free of superabsorbent material., at least in the upper half of layer 32, and generally through the majority or iodo de eu eepeeor. See U.S. Patent No. 5,217,445 (Young et al.), Issued June 8, 1993, and U.S. Patent No. 5,360,420 (Cook et al.) Issued November 1, 1994, which are incorporated herein by reference. by reference. The layer 32 may be of foam or of any other suitable porous or capillary material but is normally formed from fibrous material. The fibrous material can be any fibrous material that has adequate strength to the load when it is wetted, that is, it is able to maintain the void hollow volume under these conditions. Particularly preferred fibrous materials for layer 32 are the chemically hardened fibers as described in B (2) above, typically 50 to 100% by weight of the layer 32. The layer 40 of the upper assembly 24 may be integral with the bottom of the layer 32 but preferably a separate layer and can be separated from the layer 32 by a tissue or other component that acts as a containment barrier for the hydrogel forming polymer. It is important that layer 40 allow fluid from the body acquired by layer 32 to pass rapidly through it and be distributed beyond layer 40. The amount of the first hydrogel forming polymer in layer 40 must It is sufficient to provide a layer of hydrogel when it is swollen by absorption of bodily fluids during use. This first hydrogel-forming absorbent polymer is usually in the form of particles and may preferably be present in a quantity of at least about 20 g / m 2, more preferably in an amount of at least about 50 g / m 2. Generally layer 40 should not be too thick; Normally in the amount of the hydrogel-forming absorbent polymer it is below about 320 g / m 2 and more typically below about 200 g / m 2. The lower assembly 28 serves as the storage and redistribution component of the core 20 which includes an upper layer, usually fibrous, and a layer of the second absorbent hydrogel-forming polymer. The upper layer 44 of the lower eneamble 28 is generally fibrous but may be formed from foam or other suitable capillary or porous material, and may be formed from the honeycomb or different matrix as the layer 32. The upper layer 44 may be euslanially or completely free of the hydrogel-forming polymer absorber. However, it is often desirable that the upper and lower layers 44 and 48 be formed to provide a fibrous maize where more than half, and normally at least about 70%, of the hydrogel-forming polymer, the eelae layers are in the inferior milad of them. For example, from about 70 to 100%, more typically about 75 about 90% of the second hydrogel-forming absorbent polymer is in the lower 50% of the combined layers 44 and 48. There may be something, for example, up to about 30%, of the second hydrogel-forming absorbent polymer in the upper half of layers 44 and 48 combined. The first hydrogel-forming polymer absorbs, and sometimes also the mixed structure of the absorbent polymers formed of hydrogel, that is provided with a layer comprising predominantly the polymer or the absorbent polymers. By "predominantly" is meant that at least about 50% with and more typically at least 70 or about 80% of layers 40 or 48 is the hydrogel forming polymer. These layers of absorbent hydrogel-forming polymer can be attached to, or otherwise contained by, a support sheet. The distribution in layers 40 or 48 may be uniform in or may vary, for example, to provide a shaped die that may be in firae or profiled in layer 7 See, for example, US Patent No. 4,935,022 (Lash and oíros). ^ fc Layers 40 or 48 may comprise the absorbent polymer forming hydrogel integrated with or dispersed within a support sheet, as a cellulose-based or other non-woven material. The hydrogel forming polymer can be integrated with the carrier sheet by bonding or by mechanical means such as embossing or calendering. Alternatively, the layer 40 or 48 may conventionally comprise only the hydrogel-forming polymer. , -10 - > Additional layers can be incorporated into the absorbent core fÉ ^ 20 and, as mentioned above, layers of iris can be incorporated. For example, a fission layer can be used to encapsulate the first hydrogel-forming absorbent polymer and / or the second hydrogel-forming absorbent polymer. Other suitable absorbent core according to the pre-invention invention involves a layering of multiple layers preferably comprising: (1) an acquisition layer; (2) a storage layer whose absorbent layers comprise ^^ - a high concentration of a mixed ester of hydrogel-forming absorbent polymers that have the physical properties specified above (including the relatively high PUP capacity and preferably the PHL and SFC values) placed eubyacente to the acquisition layer; and optionally an intermediate layer, fluid-responsive, fluid-permeable, placed in front of the acquisition layer and the storage layer. The acquisition layer and the storage layer comprising for a lesser part fiber are ineenerable to moisture (i.e., fluid) as skeletal fibers that increase the wet integrity of two layers and form unionee eetablee to the fluid with other components of the abeorbenle core or the absorbent article. See United States patent application Serial No. 08 / 153,739 (Dragoo and ofroe) filed on November 16, 1993, and United States patent application Serial No. 08 / 164,049 (Dragoo and others). Presented on December 8, 1993, which are incorporated by reference. The inclusion of the fibers syntelicae enreapadae in the acquisition layer improves the integrity, acquisition coefficient, absorbency, and the resilience of the acquisition layer, encyclical einíéllicas fibers provide lanío intra-layer integrity as improved inter-layer integrity . This is due to the internal fixation of the eehenetic fiber that is enclosed within the acquisition layer and the storage layer, and the density of the fibers einlelicae found on the surfaces of these layers to form the stable bonds to it. fluid for the fluid-stable components of the absorbent core. The absorbent core in this manner provides a plurality of layers comprising internal fixation frits of fluid-stable fibers which are joined by the fluid-stable junctions to the adjacent components which are spherical to the fluid. The amphorbenite core is also bonded by the fluid-stable bonds between the euperior sheet and the posterior sheet of the absorbent article to avoid the collapse of the hydrogel-forming absorbent polymer between the top sheet and the bottom sheet (in other words, the sinking within the sheet). chassis def absorbent article). One such multi-layer absorbent core is modified in FIG. 2. FIG. 2 shows a transverse section of an article known as 110 having an upper sheet 112, a vertical 116, and an absorbent core per 120 placed between the sheet. upper 112 and backsheet 116. As shown in Figure 2, core 120 preferably comprises an acquisition / distribution layer ("acquisition layer") 130, a core storage layer ("storage layer") 132 preferably positioned underlying the acquisition layer 130, and a fluid-stable intermediate layer (or "integrity layer") 134 placed between the acquisition layer 130 and the storage layer 132, all of which are in fluid communication yes. The acquisition layer 130 may be of any suitable size and does not need to extend the length or fofal width of the layer - ^ fc storage »132. The acquisition layer 130, can, for example, be in the form of patch or fira. In the modality shown in Figure 2, the acquisition layer 130 is shown as a single patch (i.e., sheet or sheet) of nonwoven material. However, it should be understood that the acquisition layer 130 did not need an entire sheet. In addition, in modality, instead of being a separate layer that is . 10 locates at the top of the storage layer 132. the acquisition layer ^ fc 130 may be an integral layer (or component) comprising the top layer of a laminated storage layer 132. In this respect, it should also be understood that the absorbent core of mulitple layers 120 may be used as the ionic core or the core. It can be used as one or more layers in a core-in-shell construction. He The multi-layer absorbent core 120 can also be constructed without the acquisition layer. • ^^ • - The ionic acquisition layer 130 is preferably hydrophilic, may have hydrophobic components. The acquisition layer 130 may comprise a woven material, a non-woven material, or any other material of suitable material. Preferably, the The acquisition layer 130 comprises a nonwoven material. When the acquisition layer 130 comprises a nonwoven material, it may be made or by a number of different processes. These include, but are not limited to, wet-laid, air-laid, blown-in-melted, spun-bonded, carded (the latter including, thermally bonded, bonded by continuous air, bonded with powder, bonded with lax, or bonded per spin). The latter processes (for example, glued and carded yarn) may be preferred if it is desired to orient the fibers in the acquisition layer because it is easier to orient the fibers in a simple direction in this process. In a preferred embodiment, the acquisition layer 130 comprises at least that some fiber is formed by the fluid spherical bonds. The term "fluid-stable unions", as used herein, refers to the unions that are not afflicted by the preemption of body fluids. The preferred fibers for forming fluid-stable unites are fiber einigenae, the preferred fiber being especially preferred than for providing the acquisition layer 130 with euavity and re-eminence. Lae fibrae einléticae are also preferred because eefoe can be fixed immaculately to provide the acquisition layer 130 with inlegrity - "Incremental Q." The acquisition layer 130 shown in Figure 2 preferably The fc comprises a mixture of synthetic fibers encreepadae and any of the naíural fibers or reiculated cellulose fibers. In a preferred embodiment, the acquisition layer 130 comprises a mixed layer comprising a homogeneous mixture placed with air of approximately 20% hydrophobic, curled polyethylene terephlalo fibers (PET) of any air film or chemically hardened cellulose fibers. The fibers of ^ PET preferably have a denier per fiber of approximately 40, a frizz-free length of about 1.3 millimeters, a curling frequency of approximately 6 crespae per 2.54 centimeter linear, and a creep angle of approximately 88 degrees. Although the preferred material for fibers that are covered by the PET modality, the modalities of the material can be any non-waterborne material that has a wet stiffness similar to PET. Other suitable ailments to use as curled fibers include, but are not limited to, polypropylene, nylon, polyallene, and fibers of the components. In addition, the denier of the fibers preferably ranges from about 1 1/2 to 2 dpf about 30dpf. The einfiber length of the fibers preferably varies from about 0.6 centimeter to about 5 centimeters. The frequency of curls is preferably cooled to about 5 and about 15 crespae per 2.54 linear millimeters. The crepe angle preferably varies from about 60 degrees to about 100 degrees. The amount of curled fibers in the acquisition layer can vary from approximately 5% approximately to 90%, and to be practical to be used in the articles of the invention from a point of cost preferably varies from approximately 10% approximately 50%, and most preferably from approximately 20% approximately 40%. The acquisition layer 130 can be sued in a non-essential manner during the manufacturing process of the diaper. In lae modalidadee altemae, the acquisition layer 130 may be denatured by compressing it to densities that vary as high as approximately 0.3 g / cm3, or more. Additional variations may be desirable when the acquisition layer 130 is used in certain types of appendage articles. In a modality that is preferred when the absorbent article comprises a sanitary towel, the acquisition layer 130 preferably comprises a spin-linked non-woven web composed of permanently wettable fibers. Preferably, the acquisition layer 130 is a nonwoven web linked by 35 g / m2 PET spinning. The yarn linked yarns of this type are manufactured by the Veratec Company of Walpole, Massachusetts. The spunbonded nonwoven web is formed in such a way that most of the fibers are oriented in a simple direction, such as the longitudinal direction, by preferential wicking effect. The fibers of this preferred acquisition layer material 130 are made of PET resin and are coated with a permanently wettable finish known as CELWET. The fibers are obtained from Hoechet Celaneee Corp. of Charlotte, North Carolina.

An intermediate layer stable to the optional fluid 134 is preferably located between the acquisition layer 130 and the storage layer 132. The layer 134 serves two main purposes: (1) as a subemployee support for the acquisition layer 130 and the adjoining storage 132; and (2) that a structure which is stable to the fluid can be formed with the ethereal fibers in the acquisition layer 130 and the storage layer 132. The layer 134 preferably retains a high degree of integrity which, when wetted, should not interfere with movement. of the fluid from the acquisition layer 130 to the storage layer 132, and is also preferably flexible in such a way that the flexibility of the article 40 absorbent eelá susíancialmenle unaffected by the presence of the fluid layer ^ fc 134. In a preferred embodiment, layer 134 is a nonwoven web of spunbonded polyether. A commercially available non-woven polyethylene spunbonded nonwoven web for use as the fluid-responsive layer 134 which is a material known as REEMAY 2055 sold by Reemay, Incoporaled, of Old Hickory, TN. The material has a basis weight of approximately 18.6 g / m2 and is composed of fibers in the form of - ^^ three lobes in transversal section of cuairo denier by fiber. The REEMAY field is similar to the material that is used in the BOUNCE eecadorae leaves manufactured by The Procter & Gamble Comany of Cincinnati, Ohio, under United States Patent No. 4,073,996, 4,237,155, and 5,094,761. A key factor in choosing the non-woven polyester frama that is its permeability. The REEMAY frame also contains in? Ne fiber spaces that are of sufficient size to allow some of the fibers in the acquisition layer 130 to penetrate the storage layer 132 and some of the fibers in the storage layer 132 penetrate into the acquisition layer 130. 25 In alternate embodiments, layer 134 was composed of other materials that do not absorb water to be similar to polyester. Examples of materials suitable for use as the layer 134 include, but are not limited to, polypropylene, nylon, and polyethylene. In addition, in other ways instead of using einíelicoe materials, the layer 134 may comprise a tissue of high wet strength, of low stretch (ie, low extension capacity), provided in the structure in which the unionee enfre the tissue of high wet strength and the acquisition layer 130 and the adjacent storage layer 132 remain firm when wet. In alternate modalities, one can say using alpha resistance in the wet with any other type of layers set to fluid 134, including plane limited to the REEMAY material. In addition, in other alternate embodiments, the layer 134 may be a non-woven material made by another suitable process. In still other modes, the layer 134 may be of a different type of material than a non-woven material. For example, layer 134 may comprise a canvas or a network. In addition, the location of the layer responsive to the fluid in the absorbent core may vary in different embodiments. The layer 134 is preferably placed in front of the acquisition layer 130 and the storage layer 132. However, in other embodiments the layer 134 may be placed adjacent to the surface of the components of the multi-layer core 20 absorbent core. The components of the multiple layer absorbent core 120 as the acquisition layer and the storage layer comprise more than one layer, the fluid stable layer 134 may be placed between the layer comprising the components. In still alternative modes, layer 134 may comprise more than one layer. In this case, the additional layers may be ineerted between any of the components of the copolymer article. In still other alternate modalities, the fluid-stable layer 134 can be removed, in which case the synthetic fibers in the acquisition layer 130 and the storage layer 132 can be connected together directly. In the latter embodiments, the moisture-insensitive fibers in the acquisition layer 130 will be bonded to other fibers insensitive to moisture, the synthetic fibers in the storage center layer 32. The storage layer 132 is preferably placed between the acquisition layer 130 and the backsheet of the absorbent article. The storage layer 132 provides the means for sputtering and containing the fluid of the body and is generally compressible slightly in a resilient (but preferably non-collapsible), conformable, irritating manner to the skin of the dog. This layer of , 1 * 0, storage 132 may be referred to as a "mixed" layer. The layer dm Storage 132 comprises an irama or block of fibers, preferably in the form of a homogeneous mixture of fibers. The mixed storage layer 132 is comprised of at least one group (or types) of fibers. These include a first group (or type) of fibers and a second group (or type) of fiber. The first fiber group comprises relatively dense, low denier hydrophilic fiber. The second group of fibers comprises about 5%, preferably at least about - ^^ - - - 10 or 20%, approximately 90% of the fibers in the storage layer, of energetic fibers inseneible to moisture, long, higher denier. (The percentage of the fibers in the storage layer 132 refers to the relative weight of the fiber only, and not includes the weight of any hydrogel forming polymer.) The ratio of the mixture of fiber groups can be varied to produce the desired particle properties for the different types of absorbent articles. These components and the properties of the storage layer 132 are discussed in greater detail below. The fibers that in the first group of fibers can have several lengths and denote always that these properties of the fibers are less than those of the fibers in the second group of fibers. The fibers in the first group of fibers preferably have a length less than or equal to about 1.3 centimeters, more preferably less than or equal to about 0.6 centimeter. The fibers in the first group of fibers preferably have one denier per fiber (or per filament) smaller or equal to about 15, more preferably less than or equal to about 10, and most preferably less than or equal to about 2. The first group of fibers may comprise nalural fibers such as cotton or cellulose. The cellulose fibers can come in the form of fibers of trilled wood pulp known as air felt. The first group of fibers can -1.0 alternately or additionally comprise synthetic fibers, including limited length -? k to PET, polypropylene, polyethylene, rayon, chemicofermomechanical pulp (or "CTMP" or "TMP"), branches, or reliculated cellulose fibers. The fibers in the first group of the fibers are either inherently hydrophilic, or can be hydrophilic by bringing them in any of the ways previously described. 15 Operation is improved by selecting a relatively rigid fiber that maintains a substantial portion of its compression strength when it is wetted for the fibers in the first group. (That is, you decide you must have a high compression modulus.) Preferably, the selected fibers are also resistant to compression under dry and wet conditions, such as resilient in wet and wet conditions (ie, they suit to resist the compression like returning to its previous state when compressed.) Lae chemically hardened fibers are especially preferred by these criteria. The fibers in the second group of fibers are generally longer than the fibers in the first group of fibers. The fiber in the second group of fibers should also be of high compression modulus and should maintain a relatively high modulus when wet. The fiber in the second fiber group should also preferably be wet and dry resilient. Suitable fibers for inclusion in the second group of fibers include, but are not limited to, synthetic fibers composed of any of those materials specified above as Jfc being suitable for use as the fibers of the acquisition layer 130. lengths, the denier, efe, of the fiber may be the same, but not necessarily the same. For example, the synthetic fibers in the acquisition layer can have a denier (for example, a denier of about 15) to aid in the acquisition of fluid and for greater relevancy, and the fiber material in the storage layer can have a denier. minor, fal as approximately 2. Algunae longitudee , preferred fiber, etc. for the synthetic fibers in the storage layer are Fc described below. Preferably, the fibers in the second group of fibers having an uncreened length of greater than or equal to about 0.6 cm in length, preferably more than or equal to about 1.3 cm. The denier of Isa fibers in the The second group of fibers is preferably larger than the denier of the fiber in the first fiber group. The fibers in the second fiber group preferably have one denier per fiber of between about 1 1/2 or 2 and about 50 or 60, and more preferably between about 6 and about 40. More preferably still, the denier of Isa fibers in the second group of fibers is between approximately or 15 and about 30, and most preferably is between about 12 and about 25. The fibers in the second fiber group are insensitive to the fluid. That is to say, the fibers in the second group of fibers are not substantially affected by the presence of moisture (and, therefore, will not collapse when wet). Eeíae fibrae can, however, carry fluid along the surface. The fiber in the second fiber group preferably has some hydrophilic component (which may be a cellulosic component). The fibers in the second group of fibers can be provided with a hydrophilic component in a number of suitable ways. These include, but are not limited to coating or bringing fiber to make it, at least its surfaces, hydrophilic. One suitable lipo of synthetic fibers for use in the second group of fibers is the crimped polyester fibers. Suitable synthetic fibers are those previously available from Eastman Kodak Textile Fibers Kingsport Division, TN, as well as KODEL 200 and 400 series PET fibers. A suitable type of synthetic binder fiber is KODEL 410 fiber. A suitable polyester fiber is fiber KODEL 431. These The KODEL fibers have a denier of 15 per filament and a length of about 1.3 cm and are preferably crimped at a cleavage frequency of between about 5 and 8, preferably about 6, more preferably 6.3 crimps by 2.54 linear cm. The fibers are preferably crimped at a crimp angle of about 70 to about 91 °, more preferably -.15 approximately 88 degrees. Frizzing provides the fiber with improved relevancy, among other desired properties. The fibers may be coated with a hydrophilic or hydrophobic finish by any suitable method known in the art. In alternate modalities, it is possible to replace natural fibers in the first group of fibers with eintéíicae fibers, of low denier, very short (with hydrophilic surfaces). The mixed storage layer 132 in esfae modalidade would consist of the first group of low denier, short denier hydrophilic fibers (eg as a polyeefer fiber with a CELWET® finish) and the second group of long, high denier curled synthetic fibers. The mixed storage layer 132 also contains hydrogel-forming absorbent polymers in the amounts as previously discussed in C (1) above. The mixed storage layer 132 is also preferably compressed at a density of at least about 0.09 g / cm 3. The mixed layer 132 may be compressed to a minimum of at least 0.26 g / cm 3 to improve the wicking effect of the fluid (ie, the distribution of fluid to other parts of the storage layer) while still increasing maintains good softness and flexibility. The mixed storage layer 132 can be compressed at densities up to as high as about 0.35 g / cm3 to about 0.40 g / cm3. However, nuclei with higher densities become rigid instead. Therefore, if the storage layer 132 ee = 10 compressed at densities of approximately 0.35 g / cm3 to approximately 0.4Q - 4fc g / cm3, this is preferably flexed mechanically or otherwise manipulated to make it more flexible before it is placed in use. (For simplicity, the value of the deficiency specified above does not include the removal of any particles of the hydrogel-forming absorbent polymer particles.

Storage, therefore, will be greatly affected by the amount of hydrogel forming polymer in the storage layer, making it impractical to intentional ^ expire a global interval of iodo inclueive of the deneity for the storage layer.) Three components of the multi-layer absorbent core 120 preferred, the acquisition layer 130, the fluid-stable layer 134, and the storage layer 132 are preferably held together by adhesives applied on the adjacent sides of the components. The connections between the components of the absorbent core of the multi-layered layer 120 are shown particularly in FIG. 2. The side facing the body of the acquisition layer 130 is adhered to the lower side (or side thereof). towards the garment) of the topsheet 112 by the adhesive 166. The garment facing side of the acquisition layer 130 is attached to the side facing the body of the fluid layer 134 by the adhesive 167. The garment facing side of the fluid-stable layer 134 is, in turn, attached to the side facing the storage layer 132 by the adhesive 168. The absorbent core of the layer The multiplex 120 is also preferably preferably adhered between the top sheet 12 and the back sheets 116 by the movable adhesive as the sheet 166 and 169. These adhesives are elastically applied to the multi-layer absorbent core 120 and the inward facing surface. respective (or side facing towards the garment) of the upper sheet 112 (as described above) and the side facing the body of the rear sheet 116. The adhesives are shown schematically as apas in figure 2 for simplicity. However, adhesives do not need to be applied only in the form of layers. The adhesives can be applied in any of the ways described in relation to the adhesives used to join the acquisition layer to the upper sheet (for example, spirals, etc.). In addition, other types of fixing means can be used. The components of the multilayer builder core can be adhered simulcanically by any of the attachment means described above in relation to the adhesion of the acquisition layer to the topsheet. It should also be understood that the various different layers of the multi-layer absorbent core do not need the sludge to be joined by the same type of fixing means. The layers of the absorbent core multiple layers can be fixed to each other by different fixing means and / or adhesives are used, different types of applications / patterns of adhesive that can be used between the layers. In the preferred embodiment shown in FIG. 2, the layer of the multi-layer copolymer core is preferably joined by an open cell network of adhesive filaments comprising several strands of adherent filaments and twisted in a paepon in eepiral.

The synergized fibers of the acquisition layer 130 and the storage layer 132 serve an important role in the wet integrity of the components of the multiple layer absorbent core 120. The einthetic fibers are creped in the acquisition layer 120 and the Storage layer 132 should preferably be substantially long to form at least portions of the surfaces of the respective components. The synthetic fibers will typically be of sufficiently long to form at least a part of the surface of a given layer if they have lengths that vary in lengths that are equal to the thickness of the layer that this comprises haeta lengths that are greater than or equal to 50% more than the thickness of the layer they comprise. Einthetic fibers (or parts thereof) are part of the surface of the acquisition layer and the storage layer is available to be adhesively bonded to adjacent layers. Since the fibers eintéíicae eonneeneiblee to moisture, eefae were able to form the flowable joints (not shown) in the top sheet 1 12. This will ensure that the joints do not fail when the absorbent article 110 is wetted by the body exudates. The fluid-stable joints will also be formed between the facing surface of the acquisition layer of 130 and the fluid-stable layer 134 (or if there is no intermediate layer stable to the fluid, to the surface facing the fluid). body of storage layer 132). The curled synthetic fibers will also form stable bonds to the fluid between the facing surface of the fluid layer 134 and the surface facing the body of the storage layer 132. The spherical bonds to the fluid will also be formed Enlarges the clothing facing surface of the storage layer 132 and the surface facing the body of the rear sheet 116. The topsheet, the fluid-stable layer, and the backsheet are also stable to the fluid in the fluid. that these generally respect the effect when wet and are able to serve as support substrates for the other layers such as the acquisition layer 130 and the storage layer 132. The acquisition layer 130 and the storage layer 132 are supplied to eetiramiento e eeparadae by traction ^ fc under the forces associated with the use and loading of the absorbent article 110 with the body fluids. The acquisition layer 130 and the storage layer 132, however, are bonded to this fluid-stable layer at fixed binding sites. The acquisition layer and the storage layer are, in this manner, in effect, fixed to the upper sheet, the back sheet, and the fluid-soluble intermediate layer in such a way that the joints tie these non-woven layers to the layers which are stable to the outer layer. fluid. Q The acquisition layer and the storage layer are, as a result, able to use the stretch resistance of the adjacent layers to resist in-layer separation (eg, failure by an elongation or stress-related failure mechanism). due to the forces associated with the use of absorb article 110 fal as the flexing of the article, the activity of the dog, and the loading of the article with the fluid of the body. The construction of the multi-layer absorbent core described above, therefore, provides a fluid-stable synthetic synthetic fiber mat, internal fixation, and fluid-friendly components that are inherently connected and remain internally connected during use. . The multi-layer absorbent core 120 is thus resistant to both compression and tension forces (i.e., forces related to stress) such that it maintains its hollow volume and can remain in this condition. Anlee of use when it gets wet and under load it is subject to the use of the article abeorbenfe. Another suitable amphorbenfe core according to the present invention involves a primary core integrity layer, preferably formed of a continuous mesh of molten ear-melted material, which wraps around the core to provide improved core integrity, especially when wetted. See the patent of Esíadoe Unidoe No. 5,387,208 (Ashíon y oíros), issued on February 7, 1995, which is incorporated by reference. The primary integrity layer of the core which is preferably attached to a chaeie component of the article of origin, preferably attached directly to the upper sheet. The bond between the primary integrity layer of the core and the chassis composite is preferably relatively adherent and therefore tends to retain its re-eminence in that the absorbent core has a reduced tendency to separate from the component or component of the chassis. In addition, the components of the abetorbenie nucleus have a reduced tendency to freeze and / or separate one from Escucha®, particularly at! mojaree. 4fc The absorbent core enveloped by the primary integrity layer of the core preferably comprises multiple absorbents (one of which has a high concentration of a mixed stream of hydrogel-forming abeorbenis having at least the capacity of PUP, and preferably the values of PHL and SFC described in B (1) (b) above) with at least one secondary layer of integrity of the core placed in one or more of the absorbent layers. In a particularly preferred embodiment, the absorbent core comprises an acquisition / distribution layer, a storage layer, and a tissue layer placed between the acquisition / dielectric layer and the acquisition layer. storage. The secondary integrity layer of the core is preferably placed between the acquisition / distribution layer and the tissue layer. The primary and secondary integrity layers of the core are preferably formed from a thermoplastic material, preferably a thermal melting adhesive such that the core integrity layers can be formed from a thermoplastic material. easily formed in line during the construction of the absorbent article. More preferably, the integrity layers of the core are formed from an elastomeric, thermal fusion adhesive. Thermal oil adhesives, elastomeric, tend to be flexible so that there is a tendency reduced by the failures of the adhesive and / or adhering to the joint that forms unionee in the article (in relation to adhesives not elasloméricoe). As a result, the alpha nucleus has an increased tendency to remain in place and retain its integrity. More preferably, the integrity layers of the core are formed from a thermally effective elaeomeric adhesion adhesive. The stickiness of the pressure sensitive adhesive further reduces the tendency of the absorbent core components adjacent to the primary or secondary integrity layers of the core to be separated from other components of the article of origin, and is particularly effective in reducing the release / separation of the component. layer of acquisition / distribution of the storage layer. An absorbent core as indicated is shown in Figure 3. Figure 3 shows a tranevereal section of an abeorbenle article indicated as 210 having an upper sheet 212, a rear sheet 216 and an absorbent core indicated by 220 positioned between the upper leaf 212 and the foil sheet 216. As shown in figure 4, the core 220 is shown as comprising a storage layer 280 comprising the combined concentration layer of the hydrogel-forming absorbent polymers, the iris layer 270, and a layer acquisition / distribution 250. As also shown in Figure 3, at core 220 it also has a primary core integrity layer 230 and a core integrity secondary layer 240. The core integrity primary layer 230 is placed between the sheet back 216 and storage layer 280. The secondary integrity layer of core 240 is placed in front of the acquisition layer / dieffibuc ion 250 and the iris layer 270. As also shown in Figure 3, the core integrity primary layer 230 extends beyond and envelops the side edges of the acquisition / dissolution layer 250, the side borders of the layer of 270, the side edges of the storage layer 280; and To the surface that faces towards the garment of vetting the core 220. FIG. 3 also shows layers of construction adhesive 290, 92, 294 and 296. As shown in FIG. 3, the core integrity layer 240 is bound together. to the tie layer 270 by the construction adhesive layer 292. The core integrity secondary layer 240 is placed adjacent to the acquisition / distribution layer 250. Depending on the bonding strength of the secondary integrity layer material. from the core 240 to the acquisition / dissolution layer 250, the secondary integrity layer of the core 240 can be attached to the acquisition / distribution layer 250 by the properties of the thermal fusion or the properties is suitable for the precession of the material of the secondary integrity layer of the preferred core 240. As further shown in Figure 3, the shell of 270 is bound to the storage layer 280 by the connecting adhesion layer 294. The primary integrity layer of the core 230 is placed adjacent to the outer layer.

Storage 280. Depending on the bonding strength of the core integrity primary layer material 230 to the storage layer 280, the primary layer The integrity of the core 230 can be connected to the storage layer 280 by the thermal or pressure sensitive properties of the material of the primary integrity layer of the preferred core 230. 20 As shown more in Figure 3, the acquisition / distribution layer 250 is joined to the upper sheet 212 by the construction adhesive layer 290. The core integrity primary layer 230 is joined to the back sheet 216 by the construction adhesive layer 296, and to the top sheet 212 by the thermal fusion properties or Eeneibles to the pressure of the material of the primary integrity layer of the core 230. As shown in Fig. 3, the adhesive adhesive layer 290 exudes outwardly from the side edges of the acquisition / dielectric layer 250 and towards denir of the side edges of the tissue layer 270. The construction adhesive layer 290 may be wider than the tissue layer 270 to effect the joining of the core integrity layer 230 to the top sheet 212. However, for For economic reasons, an application of a construction adhesive will normally be made to effect such a joint. The adhesive adhesive layer 292 is shown in FIG. 3 to extend in the same way as the construction adhesive layer 290. The adhesive bonding layer 294 extends toward the side of the side of the storage layer 280, and for The maximum economic density preferably exceeds a maximum linear dissipation of approximately about the maximum width of the storage layer 280 in the region of the bottom of the web. abeorbenie nucleus. As shown in Figure 3, the construction adhesive layer 296 extends from the edge of the primary integrity layer of the core 230. The forming adhesion layer 296 can alternatively extend outward from the side edges of the layer. of the integrity of the core 230 in order to effect the juncture of the backsheet 116 to the top sheet 212. In a preferred embodiment, the construction adhesive layers 290, 292, 294 and 296 are applied over the longitudinal length (non-mossy). ) fc by at least one of the acquisition / dieffibration layer 250, the? 270 layer, the storage layer 280, the backsheet 216, the upper sheet 212. The primary integrity layer of the core 230 which preferably envelops at least one layer of the copolymer core 220 and which is attached, preferably directly attached, to a component of the chassis (for example, the upper sheet 212 or the back sheet 216) of the article. Absorbent ulo. The primary integrity layer of the core 230 tends to improve the integrity of the absorbenfee layers it wraps. In this manner, in a preferred embodiment, the core integrity primary layer 230 wraps each of the layers of the absorbent core 220. The following description is therefore directed to a primary layer of integrity of the core enveloping each of the layers. layer of the absorbent core 220. However, it should be understood that the improvements that absorbency of the core can be obtained by using a configuration in which the primary core integrity layer envelops only one or some of the absorbent layers of the core absorbent 220. For example, the integrity of the acquisition / distribution layer 250, and thus of the absorbent core 220 incorporating the same, it can be improved by wrapping only the acquisition / delivery layer 250 with the primary integrity layer of the core 230. In addition, the primary integrity layer of the core that does not involve any of the core absorbers can be used to improve the integrity of the core. absorbent core. For example, the dimensions of the surface area of the primary integrity layer of the core may be smaller than those of each of the absorbent core layer (the primary integrity layer of the core would then be placed and bonded as described herein for a secondary layer of integrity of the core that does not involve any of the layers of the absorbent core). However, it is believed that the increased integrity of the absorbent core is achieved where the primary integrity layer of the core envelops the at least one layer of the absorbent core, which prefers this mode. By "wrapped", it will be understood that the core integrity primary layer 230 encloses or surrounds at least a portion of the absorbent core 220 that (or layer thereof). In a preferred embodiment, the primary integrity layer of the core 230 involves at least a portion of the side edges of the absorbent core 220 and at least one portion of the core of the absorbent core. The primary integrity layer of the core 230 will typically envelop the laminated edges of one or more layers in the Y-Z dimension. The primary core integrity layer 230 additionally serves to retain the abehorbenite core 220 in a relatively sensible pore, since the absorbent core will be physically limited by the primary core integrity layer. It is also believed that the primary integrity layer of the core 230 helps to maintain the adhesive bonds that typically connect the absorbent core and the component of the substance of the article, for example, where an adhesive is used. consirucción to join only components. The primary integrity layer of the core is particularly useful in maintaining the integrity of the adhesive bonds that typically bind the cellulose fibers of the copolymer core 220 to a polymeric chaeie, more particularly a chaeie formed of or coated with a synthetic polymeric material (as eective). "Polymeric and euphemistic chaeie"). 0 Because the primary integrity layer of the core 230 forms a Relatively strong union and physically limiting the absorbent nucleus 220, the primary integrity layer of the core reduces the forces found by the unions of polymeric chaeis of relatively weak cellulosic fiber-building adhesive, which has a tendency to unite. reduced to breaking. In addition, if the union of polymeric cellulosic fiber cement adhesion sheet fails, the chassis bond of the relatively strong core integrity primary layer retains the absorbent core in a relatively stable position. In this way, the absorbent core has a reduced tendency to separate from the chassis component. This positive effect on adhesion can be particularly important when wetting or the absorbent article. When the cellulosic fibers and the hydrogel-forming absorbent polymer that are incorporated within the absorbent core expand upon wetting, the forces exerted by the cellulosic fiber and the hydrogel-forming absorbent polymer expand to cause a loss of adhesion between the fibers, the polymer absorbent formed of hydrogel, and the chassis (the adhesion failure occurs to occur between the fiber and / or the hydrogel forming polymer and the adhesive, instead of the chafer and the coneffective bond).

By effectively reeferring the builder core, the primary integrity layer of the core 230 also reduces the tendency for the other layers of the absorbent core 220 to zap and / or separate into one another. This tendency towards slipping and / or reduced eeparation of the core of the core integrity layer comprises a sticky pressure sensitive material. It is known that the physical resliction described above, the bonding of the chasie of the primary layer, the integrity of the relatively strong core, and / or the tackiness reduces the tendency of the absorbent core or components of the member to sink, break and / or make strands. As a solvent, the absorbent core is used more efficiently so that the absorbent article has improved absorption characteristics and reduced leakage. The primary integrity layer of the core 230 comprises a confined, fluid-permeable mesh of uro-plasmatic material. The thermoplastic material is preferably a thermally active adhesive, preferably a thermally active, pressure sensitive adhesive. The thermoplastic material is also preferably elaetomeric. By "Mesh", it is understood that the thermoplastic material is in the form of hyioe that are interconnected to form openings. As they are formed by a melt-blown process, the individual yarns are preferably sinuous (wavy) and oriented in the directionally direction with at least one tranevereal bond to form an entangled line of yarn. "Hiloe" is to include fibers, strands, filaments, and other shapes that have a longitudinal dimension to the relatively large transverse section. By "fluid-permeable mesh", it is implied that the mesh has a sufficiently large opening aperture per unit area to allow the fluid to be relatively unimpeded from the mesh. In this way, the mesh has a basic weight as described here. By "continuous" Mesh, it is implied that substantially all the threads would be connected to at least one other thread. Typically, the threads are coherently connected to each other where the threads intersect. (As understood in the art, cohesion refers to the force that holds together the adjacent Jfc molecules of a simple material.) As used herein, the "relatively cohesive" bond. is believed to result from a force of attraction between 2 or more materials and, for example, two or more polymeric materials.) Varioe maferialee fermoplasticus fal may be used as known in the art to make the first layer of core integrity 230. Examples of the erymoplastic materials include the monomer polymers efilénicameníe unscathed ía! such as polyallene, polypropylene, polyester, polyvinyl chloride, acetylene ^ fc of polyvinyl, polymelyyl melacrylic, polyallyl acrylate, polyacrylonyl, and the like; copolymers of eilylenically unsaturated monomers such as copolymers of ethylene and propylene, styrene, or polyvinyl acelaide; anhydrides of styrene and maleic, methacrylate, acrylate, or acrylonitrile; methyl methacrylate and elylacrylate; and eimilaree, polymere and copolymer of conjugated dienoe as polybutadiene, polyisoprene, polychloroprene, sulfite-buadiene rubber, ethylene-propylene-diene rubber, acrylonitrile-sryrene rubber buladiene Mk and the like; saurous and insalurated polyesters including alkyds and other polyesters; nylon and oírae polyamidae; poliesleram.das and poliureíanos; chlorinated polyether epoxy polymers; and esterulo celluloea lal as cellulose acetylate buíirate, and eimilar. Mixtures of thermoplastic materials, including, but not limited to, physical blends and copolymers can also be used. Particularly suitable thermoplastic materials include polyethylene, polypropylene, polyesteree, ethylene vinyl acetate, and mixtures thereof. A number of thermal fusion adhesives can also be used as know in the art. Thermal fusion adhesives are typically coated on one or more types of thermoplastic materials, such as those described above. In this way, the thermally active adhesives used herein may be a feropolylic material or a composition comprising a thermoplastic material. The various thermal fusion adhesives known in the art are suitable for use in the present. *. The thermoplastic material is preferably elaeomeric. Elasomeric materials are believed to be particularly useful for maintaining the integrity of the absorbent core while the core is subjected to bending or torsional forces as encountered during the operation. More particularly, it is believed that the elastomeric adhesives have better adhesion to the components of the article Absorbent than non-elastomeric adhesives, particularly under the dynamic conditions encountered in the use of the absorbent article. By "elastomeric", "elastic", etc., it is implied that the material is capable of being stretched at least twice its original length and approximately re laugh at its original length when it is released. Elasfomeric hot-melt adhesives exemplare include elastomers thermoplastics such as ethylene vinyl acetate, polyurethanes, polyolefin mixtures of a hard component (generally a polysolphine criselline as polypropylene or polyethylene) and a soft component (as an ethylene propylene rubber); copolyesters such as poly (ethylene glyphosate-co-ehylene); and elastomeric block copolymers, erymoplastics having blocks of erymoplastic exíremo and medium blocks of rubber denoted as block copolymer A-B-A; mixtures of homopolymers or spherically different copolymers, for example, a mixture of polyethylene or polystyrene with a block copolymer A-B-A; mixtures of an elastomeric elastomer and a low molecular weight reine modifier, for example, a mixture of a styrene-isoprene-styrene block copolymer with polyesirene; and elasomeric adhesives, of thermal fusion, senesible to the pressure described here. The elastomeric, fusion-melt adhesives of these types are described in greater detail in U.S. Pat. No. 4,731,066 (Korpmann) issued March 15, 1988, which is incorporated by reference. The thermal melt adhesives for forming the primary integrity layer of the core are the thermally active adhesives, which are necessary for the precession. Loe adheeivoe Thermal sterilization, amenable to precession, as it is understood by those of ordinary skill in the art, has some degree of surface stickiness to the femperaires of ueo. The sticky materials typically have a similarity at ambient temperature (from approximately 20 ° C to approximately 25 ° C) which is sufficiently low to allow good surface contact, still sufficiently 1Q I raise to restrain the separation during tension. Typically in the order of 10 - ^ 06 a ^ ceníipoise. Due to their surface tackiness, the pressure sensitive adhesives here tend to increase the coefficient of friction between the components of the absorbent article which may be adjacent to the adhesive seleable to the precession, eg, the layers of the absorbent core. In addition, pressure-sensitive adhesives are provide manufacturing flexibility since the joining or joining of the core integrity first layer to other component parts of the absorbent article may occur later.

By means of the properties sensitive to the pressure of the adhesive after the adhesive has solidified. Various heat-sensitive, pressure-sensitive adhesives are known in the art and are suitable for use herein. The preferred adhesives, pressure-sensitive, heat-fusion adhesives are also elaspheres. The adhesion-sensitive adhesives of the elatomeric thermal oil eelon disclosed in U.S. Patent No. 4,731,066, referenced and incorporated above, and include those materials based on vinyl acetate, polyacrylates and block thermoplastic copolymers. The adhesivoseneable to the Suitable pressure, thermal fusion, elastomeric, include adhesives based on block copolymers of A-B-A that are specified as H-2085 and H-2031 by Findley Adhesives, Inc., of Wauwatosa, Wl. The primary integrity layer of the core 230 can be formed using a fc process from blowing in molten fiber from the fiber. Loe proceeoe in the past Fused fiber are generally known in the art. In general, the thermoplastic material is heated and maintained at a sufficient temperature to allow processing by extrusion and blowing, typically leaving the material in a liquid or molten state (melting temperature / liquefaction). (In general, the selection of any given temperature in the process of extrusion by melting and blowing is limited by the time of degradation of the iron-plating material. ^ fc particular that is processed.) The liquefied / molten material is extruded under pressure (pressure gun) through the holes in a blown and blown extruded rubber gun. Above the extrusion, the liquid / molten material is subjected to air flow under pressure (pressurized air) that fibrates the material (the filaments are formed). The meltblown and blown rubber gun and the air are heated to a desired rubber temperature and air temperature, respectively, in order to facilitate the formation of the filaments. During and / or after the formation of the filaments, the thermoplastic materials are cooled to form spherical filaments of the fermoplastic material. The apparatus is configured such that the filaments lie on a desired subframe. The parameters of the extrusion process by melting and blowing are preferably selected to provide a mesh having a certain orientation of filaments and denier. These parameters include the temperature of melting / liquefaction, temperafura of the pietola, and temperafura of the air. In a preferred embodiment, the parameters are varied to facilitate the formation of einuoeoe filaments (onduladoe) which are oriented eubefancialmente in the same direction with some links franevereales to form a rama of filaments enlreiejida. Additionally, it is generally necessary to form relatively large filament denier, because the degree of wetting of the fermoplastic material to the absorbent core and thus the degree of improvement in the integrity of the absorbent core increases with increased filament denier. The filaments preferably have a denier of at least about 60 microns, preferably from about 80 microns to about 200 microns, more preferably about 90 to 200 microns, preferably about 100 to about 200 microns. In general, as the viecoeidad of thermoplastic material being exempted "Q by melting and blowing decreases, filament formation occurs more easily, with the Jfc reeultani filaments tending to have a finer denier. Viscosity also influences the orientation of the filaments, tending to become randomly oriented with decreased viscosity. The viscosity of a given material typically decreases with a melting / liquefaction temperaure that increases and particularly with a temperalura of pisíola that increases. Therefore, the lemperalurae of melting / liquefaction and guns are ^ fc selected to provide a viscosity that facilitates filament formation as desired. w The melting / liquefaction temperature is from around 121 ° C (250 ° F) at about 204 ° C (400 ° F) preferably around 149 ° C (300 ° F) at about 190 ° C (375 ° F). The adhesives designated as H-2031 and H-2085 are typically maintained at a temperature of from about 135 ° C (275 ° F) to about 204 ° C (400 ° F), preferably around 149 ° C (300 ° C). F) at about 177 ° C (350 ° F), more preferably around 165 ° C (330 ° F). 25 Gun temperafure is spiked at or above the melting / liquefaction lemma, preferably above the last temperature in order to facilitate the formation of filamenloe. The lyrical gun operation is from about 149 ° C (300 ° F) to about 204 ° C (400 ° F), preferably around 163 ° C (325 ° F) to about 190 ° C (375 °). F), more preferably around - of 182 ° C (360 ° F). 5 The air pressure influences both the orientation of the filaments and the denier. For a given material and a set of process lemperaires (particularly piezo and air temperalurae), as the air pressure increases, the filameniums tend to form in a more random orientation and with a finer denier. The air pressure is preferable at the earliest in the industry to form filaments of material , .1Q. thermoplastic in a sufficiently molten liquid state, as described below.

In a preferred embodiment, the air pressure is selected so as to facilitate the formation of filaments by efficiently rolling the directional side with some intertwined bonds to form an entangled filament web. Therefore, he prefers that the air pressure is not so high as to make the formation of filaments in random orientation. Typically, the air pressure ranges from about 4 pei (26 kPa) to 15 pei (103 kPa), preferably about 6 (41 kPa) to about 10 pei (69 f ^ k kPa), more preferably about 7 (48 kPa) at around 9 psi (62 kPa), most preferably around 8 psi (55 kPa). The air temperature will generally be selected to maintain the thermoplastic material exempted in the molten / liquefied sphere. Consequently, the temperature of the air will usually be greater than or equal to the temperature of the piezole in order to interpenetrate any cooling eff ect that could otherwise occur. Preferably, the air operation is sufficient to ensure the interconnection of the individual filamenloe of the thermoplastic material on the eubetrafo (despite the that the exempted material need not be in the same molten state / liquefaction as when the first extruded first, preferably is efficiently molten / liquefied to facilitate the interconnection of the filaments). Typically, the air temperature is from about 204 ° C (400 ° F) to about 238 ° C (460 ° F), preferably from about 215 ° C (420 ° F) to about 227 ° C ( 440 ° F), more preferably around 221 ° C (430 ° F). By cooling to a temperature sufficient to re-solidify the thermoplastic material, it is possible to isolate the coalescing mesh of the interconnected filaments. The thermoplastic material is applied to the eubelrate (for example, a component of the absorbent core) so as not to interfere sub-surface with the absorption of the absorbent core. So, the base weight of the mesh of the typical feroplasic material is from about 2 to about 8 gram per square centimeter (g / c 2), preferably from about 3 to about 7 g / cm 2, more preferably around 4 to about 6 g / cm2, most preferably about 5 g / cm2. The blown and cast extrusion equipment here is typically selected according to the width of the absorbent core (or core component) absorbent) which will be wrapped. In general, the equipment is selected as the one that provides, in a single step, a mesh width of the thermoplastic material that is ^ fc euflient to wrap the nucleus abeorbente. (Where a core core integrity layer or core integrity core layer as described herein is not intended to involve at least a portion of the side edges of a core component.

The absorbent core, the extrusion blown and blown rubber gun is selected to provide a mesh width that is less than the width of the absorbent core component). For the absorbent articles here, it is convenient to have a 2, 3.0"(13 cm) wide module of the melt extrusion rubber tubing and so-called AMBI-3.0-2 and a 4, 6" module (26 cm) ) wide rubber gun of extrusion by melting and blowing designated AMBI-6.0-4, each available from J and M Laboratories of Dawsonville, GA.

The primary integrity layer of the core 230 preferably is formed by the extrusion process by melting and blowing in a continuous (in-line) process during the manufacture of the absorbent article. Alternatively, the primary layer of integrity of the core can be formed by the melt extrusion and blow molding process. above or by conventional methods in an intermediate process for the subsequent incorporation of the absorbent article. Therefore, the primary integrity layer of the core can be a preformed, non-woven, fluid-permeable web comprising filamentous feropolyelic filaments. However, because the use of preformed non-woven filaments tends to add to the last cosfo of the article Absorbing, this alternative is not preferred. As described above, the integrity layer of the absorbent core 230 preferably is placed in such a manner as to surround the absorbent core 220. The primary integrity layer of the core is also attached to at least one of the chassis components (e.g. the top sheet 212 and the back sheet 216) of the absorbent article 210. In a preferred embodiment, the primary integrity layer of the core 230 is directly attached to a chassis component, preferably to the sheet ^ fc upper 212. The primary integrity layer of the core may be joined to a chassis component by a construction adhesive. Alternatively, the absorbent core layer may be attached to a chasie component by the property. of thermal iron or sensitivity to the pressure of the thermoplastic material of the primary layer of the core, where they use materials. In a preferred embodiment, the integrity layer of the primary absorbent core 230 is directly bonded to the chassis component by a construction adhesive. Suitable construction adhesives include any of the loe adhesive materials such as are known in the art of attaching nucleus abeorbenfee to the components of the chasie, including those described herein in reference for joining the back sheet 216 and the abeorbenle core 220. The building adhesive can comprise any of the fusion adhesives. described in reference to the thermoplastic materials to form the primary integrity layer of the core. Jfc Construction adhesives can be applied to a given substratum (for For example, the primary integrity layer of the core, an absorbent core component, or a chassis component) is conventionally used as described herein in reference to the attachment of the backsheet and the absorbent core. Preferably, the construction adhesive is applied in an open pattern of construction adhesive. As it is used here, "open pairing of construction adhesive" means that the bond of bonding is present on a sub-row in a payroll that fc allows the transport of relatively unimpeded fluid in and / or throthe absorbent core. The open pads and methods of making the same are described in the Patents of the United States and Noe. 4,573,986; 3.911, 173; 4,758,996; and 4,842,666, which are here incorporated by reference. Therefore, the open payroll of The bonding adhesive may comprise a thin globuletee pattern of bonding adhesive or reliculated filament bonding adhesive, including Jfc spiral and / or drop paírones. The globules and filaments may have diameters about equal to the order of magnitude of the effective average diametre of the fibers that make up the absorbent core 220. The construction adhesives are also can be applied by a process of extrusion by melting and blowing, including the described process to elaborate the primary layer of integrity of the core. In a preferred embodiment, the absorbent core 220 comprises a secondary integrity layer of the core 240 positioned between several absorbent layers, preferably webs or sheets of the absorbent core. (As will be understood by of ordinary skill in the art, the absorbent layers may, like the absorbent core, have a surface facing the garment, face-to-body surface, border the collar, and border the outer layer. The abehorbenfe core 240 in the preferred absorbent articles 210 will be placed between the integrity layer of the absorbent core 230 and the chassis component to which the primary integrity layer of the core is attached. (However, where the primary layer of The integrity of the core involves only a portion of the layers of the absorbent core 220, a layer of integrity of the core can be placed between the layer of the absorbent core that is not enveloped by the primary layer of core integrity). The core integrity secondary layer 240 comprises a continuous mesh of thermoplastic material, as defined in reference to the core integrity layer of the core.

The secondary integrity layer of the core 240 is attached to a chassis component and The fc can be attached directly to the previous one, for example, where the secondary integrity layer of the core envelops the absorbent core layers placed between the secondary integrity layer of the core and the chaeie. The core integrity core layer 240 may or may not wrapping one or more layers of the amphorbenite core 220. As shown in Figure 3, the lateral width of the core integrity core layer 240 is smaller than the width The lateral side of each of the absorbent layers of the absorbent core, for example, in lateral width of secondary layer of integrity of the core 240 is smaller than the lateral widths of each of the acquisition / distribution layer 250, tissue layer 270. , and storage layer 280). As a consequence, the secondary integrity layer of the core 240 does not envelop the lateral borders of, respectively, the acquisition / delivery layer 250, the iris layer 270, and the storage layer 280. The secondary integrity layer of the core 240 alternately can wrap the absorbent layers as described for the primary integrity layer of the nucleus 230. The extent of the envelope may be the same or different from that of the primary integrity layer of the core of any other secondary layer of core integrity. Thus, the secondary integrity layer of the core 240 may involve relatively different length portions of side edges of an absorbent layer, and / or a different surface and / or relative portion of a surface of an absorbent layer. The secondary core integrity layer 240 can be formed of a thermoplastic material and by a process as prescribed for the primary core integrity layer. The core integrity core layer ee can be formed from the same thermoplastic material as the core integrity primary layer 230 or from a different thermoplastic material. For ease of procedure, the secondary integrity layer of the core is preferably formed of the same thermoplastic material of which is the primary integrity layer of the core. Additionally, the secondary integrity layer of the core can be formed using the processing parameters that are of the same or different shape than those used to form the primary integrity layer of the core. Preferably, the same process parameters are used so that the secondary layer of integrity of the core has a basis weight, and the filaments of the thermoplastic material of the previous one have a denier and orientation, which are substantially the same as that of the primary layer. of core integrity. The core integrity secondary layer 240 may be attached to one or more layers of absorbent cores and / or to a chassis component. Bonding can occur using a sealing adhesive and / or the thermal fusion and / or pressure sensitivity properties of the core integrity secondary layer material, as described for the bonding of the primary integrity layer of the core. core to a chasie component. The absorbent article 210 shown in Figure 3 can be formed in the following manner. A secondary integrity layer of the core 240 is formed on the face of the garment of the acquisition / distribution layer 250. The secondary integrity layer of the core 240 is bound to the tissue layer 270 by the layer of construction adhesive 292 which preferably is applied to the body facing surface of the tissue 270. Then, the body facing surface of the tissue layer 270 s Jfc attaches to the storage layer 280 by the bonding layer 294 which preferably is applied to the facing face of the garment of the tissue layer 270. The resultant laminate is then joined to the topsheet 212 by the construction adhesive layer 290, which attaches the acquisition / dielectric layer 250 to the upper sheet 212. The primary integrity layer of the core 230 is formed on the garment facing surface of the storage layer 280, a portion of the surface of 0 against the garment of the tissue layer 270 (correspondingly to differential lateral distance ^ fc between the side edges of the storage layer 280 and the side edges of the liner layer 270), and a portion of the garment facing surface of the topsheet 112 (corresponding to the differential differential distance in loe). lateral edges of the tissue layer 270 and the lateral edges of the primary integrity layer of the core 230). Thereafter, the foil sheet 216 is attached to the core integrity primary layer 230 by the adhesive bonding layer 296 and the foil sheet 212 by a fc adhesive with the (non-stretched) adhesion. Another suitable core according to the present invention may be in the form of a mixed foam layer of absorbent or hydrogel-forming polymers contained in two or more layers of fibers, for example, a laminated absorbent core. Suitable laminated absorbent cores according to the present invention can be prepared using procedures similar to those described in United States Patent No. 4,260,443 (Lindeay et al); U.S. Patent No. 4,467,012 (Pendersen et al) issued on Aug. 21, 1984; 5 Patent of the United States No. 4,715,918 (Lang), issued on December 29, 1987; United States Patent No. 4,851, 069 (Packard et al.), Issued July 25, 1989; U.S. Patent No. 4,950,264 (Osborn), issued August 21, 1990; Patent of Esfadoe Unidoe No. 4,994,037 (Bernardin), issued on February 19, 1991; Patent of Esfadoe Unidoe No. 5,009,650 (Bernardin), issued on April 23, 1991; U.S. Patent No. 5,009,653 (Osborn), issued April 5, 1991; U.S. Patent No. 5,128,082 (Makoui), July 7, 1992; U.S. Patent No. 5,149,335 (Kellenberg et al.), Issued September 22, 1992; and U.S. Patent No. 5,176,668 (Bernardin), issued January 5, 1993 (which are all incorporated herein by reference) but with a mixed layer of absorbent polymers that form hydrogel that have at least the PUP capacity and preferably the PCH and SFC values described in B (1) (b) Jfc above. Other suitable laminated absorbent cores according to the present invention involving thermally bonded layers are disclosed in Patent Application Serial Number 141, 156 (Richards et al.), Filed on Oc. 1993, which is here incorporated by reference. These thermally bonded absorbent cores comprise: (1) a primary thermally bonded fluid distribution layer; (2) optionally, but preferable a secondary fluid distribution layer in fluid communication with, and being capable of acquiring aqueous body fluids from, the primary distribution layer; (3) a storage layer of Fluid in fluid communication with the primary or secondary fluid distribution layer comprising a high concentration mixed layer of hydrogel-forming absorbent polymers having at least the PUP capacity and preferably the PCH and SFC values described in B ( 1) (b) above; and (4) optionally a "dedusting" layer adjacent to the storage layer. Esloe core absorbers are typically used together with a thermally bonded acquisition layer (referred to as an "upper secondary sheet").

One embodiment of thermally bonded absorbent cores is shown in Figure 4. Figure 4 shows a cross section of an absorbent article particularly convenient as a calamenial indicated as 310 having a superior fluid-permeable upper sheet 312., a fluid impermeable backsheet 316 and an absorbent structure positioned between the topsheet 312 and the backsheet 316 comprising a fluid acquisition layer 314 commonly referred to as a "secondary topsheet" and an absorbent core indicated by 320. As shown in this figure, the absorbent core 320 is shown in Figure 4 as comprising three components: a fluid die layer 324, a storage layer 326 and a fibreous "dedusting" layer 328. In the formation of these articles The absorbent layer, the "de-oiling" layer 328, provides the initial layer on which the mixed layer of hydrogel-forming polymer and copolymer is deposited, from the storage layer 326. Deepuée, the distribution layer 324 is placed on the mixed material line absorbenide that forms hydrogel deposited forming a laminated type stmfure. Although it is possible to join the dedusting layer 328 and the distribution layer 326 by the use of an adhesive, these two layers are typically joined together by thermal uniopee because each of these layers comprises some iremoplastic material, typically fermoplastic fibers. In Figure 5 an alternative embodiment of this thermally attached absorbent core is shown. Figure 5 shows a transverse section of a particularly suitable article of appearance such as a catamenial indicated as 410 having a top sheet 412, a back sheet 416 and an abeorbenite core indicated as 420 placed between the upper sheet 412 and the posterior sheet 416. As shown in Figure 5, the absorbent core 420 comprises four components: a primary fluid dissipating layer 424, a secondary fluid distribution layer 430, a fluid storage layer 426, and a fibrous "dedusting" layer 428 .

Again, the "dedusting" layer 428 provides the punch for depositing the mixed deposition of the hydrogel-forming polymer and the hydrogel of the storage layer 426. The primary and secondary distribution layers 430 and 424 are placed on the polymer and are deposited to form a hydrogel. a structure of type of laminate. These laminates are joined together by thermal bonding. Figure 6 shows a combination of the modality of the moefradae in figures 4 and 5. As in the embodiment shown in figure 4, the absorbent article 510 comprises an upper sheet 512, a lower sheet 516 and an abeorbenle structure placed in front of the upper sheet. 512 and the sheet 516 comprising a sheet . euperior eecundaria 514 and an abeorbent nucleus 520. Like the modality shown in ia Figure 5, the absorbent core 520 of Figure 6 comprises four components: a primary fluid distribution layer 524, a secondary layer of fluid distribution .5.0, a fluid storage layer 526 and a fibrous layer of "dust removal". "528. Other suitable absorbent cores can be prepared according to the present invention from synthetic meltblown and blown fibers and The mixtures of coform (for example, mixtures of cellulosic fibers and synthetic oils by extrusion and blowing, and by ethex), such as those disclosed in United States Patent No. 5,149,335 (Kellenberg et al. September 1992, which is incorporated herein by reference. For example, a shaped fiber comprising 75% absorbing polymer forming hydrogel having at least the PUP capacity can be formed, and preferably the PCH and SFC values described in B (1) (b) above and 25% of a HYDROFIL® LCFX fiber copolymer of meltblown and finely fibrated extrusion (less than about 5 micron diameters).

The fiber extruded by fire and then blown is coated on a surface with a meltblown extrusion layer by blowing and blowing HYDROFIL® (see Examples 2 and 3 of U.S. Patent No. 5,149,335). The absorbent core then formed is placed between two layers of bilobal polypropylene spunbonded material (see Examples 2 and 3 of U.S. Patent No. 5,149,335) with the spun material.

Jfc stuck being heat sealed around the periphery of the builder structure. - 5 The core absorbers containing a layer of meltblown and blown fibers and absorbent polymer particles forming hydrogel having at least the PUP capacity and preferably the PCH and SFC values described in B (1) (b) above can also be formed in accordance with the procedure described in U.S. Patent No. 4,429,001 (Kolpin et al.), issued January 31, 1984, which is incorporated by reference. For some absorbent articles, two or more layers formed separately from those meltblown and blown fibers and absorbent polymer particles can be assembled to form thinner absorbent cores. Also the stream of melt-blown extrusion fibers and absorbent polymer particles can be deposited in the sheet material. as a porous nonwoven web that is to form part of the eventual absorbent core. Other fibers except meltblown and blown fibers can be ^ fc enter inside the absorbent center. For example, wavy bulky fibers can be mixed with meltblown and blown fibers together with absorbent polymer particles to prepare a higher weight or absorbent core. light. E. Absorbent Articles Due to the unique absorbent properties of the absorbent centers of the present invention, they are especially suitable for use in absorbent articles, especially disposable absorbent articles. As used here, the The term "absorbent article" refers to articles that absorb and contain bodily fluids, and more specifically refers to articles that are placed against or in proximity to the user's body to absorb and contain the various fluids discharged from the body. Additionally, the "disposable" absorbent articles are those that are intended to be disposed of after a single use (for example, the original absorbent article as a product was not intended to be washed or discarded). of some other form restored or reused as an absorbent article, so that it may be possible to recycle, reuse or composing). A preferred embodiment of a disposable absorbent article according to the present invention is a diaper. As used herein, the term "diaper" refers to a garment that is usually worn by infants and incontinent persons who dress 1Q around the lorso mae under the user. However, it must be understood that ^ fc invention is also applicable to incontinence bursts, incontinence pads, diaper inserts, calamenial pads, iaallae eanifariae, facial tissue, paper towels, between ears. These absorbent items typically include a sheet from impervious to the fluid, a liquid-permeable sheet attached to, or otherwise affixed to, the backsheet, and an absorbent core according to the present invention.

Jfc Invention placed between the top sheet and the back sheet. The top sheet is placed adjacent to the body surface of the absorbent core. The top sheet is preferably bonded to the abehorbenie core and the backsheet by means of such as those well known in the art. As it is used here, the term "joined" encloses configurations in which an element is directly secured to the other by fixing the element directly to the other element, and configurations in which the element is indirectly secured to the other element, fixing the element to the intermediate member (e) as once they are fixed to the element element. In the articles Preferred absorbent, the upper sheet and the lower sheet are directly joined together at the periphery of the previous one. The euperior sheet and the posterior sheet may also be indirectly joined together by attaching them directly to the absorbent core by the fixing means. The backsheet is typically impervious to body fluids and is preferably made from a thin plastics film, to the effect that it can also use flexible, fluid-impermeable materials. As used herein, the term "flexible" refers to materials that are docile and easily conform to the general figure and connornos of the human body. The posiérior sheet prevents the bodily fluids absorbed and contained in the amphorbeny nucleus to wet the articles that are in cones with trousers, pajamas, underwear, and the like. The backsheet may comprise a woven or non-woven material, solid polymeric films such as poly-pylene or polypropylene fermoplastic films, or composite materials such as non-woven materials covered with film, preferably, the backsheet is a polyethylene film having a thickness of from about 0.012 mm (0.5 mil) to about 0.051 mm (2.0 mil). Exemplary polyielylene films are manufactured by Clopay Corporation of Cincinnati, Ohio, under the designation P18-0401 and by Ethyl Corporation, Visqueen Division, of Terre Hauie, Indiana, under the designation XP-39385. The backsheet is preferably embellished and / or finished in matte to provide a similar appearance to a veil garment. Additionally, the backsheet may allow vapors to escape from the absorbent core (eg, breathable) while still preventing body fluids from passing through the backsheet. The posirior sheet is docile, soft to the de facto, and does not irritate the skin of the user, in addition, the upper sheet is permeable to the fluid allowing the body fluids to penetrate easily through its thickness. A convenient top sheet can be manufactured from a wide range of material materials such as woven and non-woven materials, polymeric materials such as ferroplastic films of formed openings, aperture thermoplastic films, thermoplastic films and hydroformed films.; Porous sponges, reticulated sponges, reticulated thermoplastic films and leroe pneumoplastics. The maíerialee fejidoe and suitable nonwovens ^ fc may be comprised of natural fibers (for example cotton or wood fibers), synbolic fibers (for example polymeric talee fibers such as polyethylene polypropylene or polyester fiber). Or from a combination of synthetic and natural fibers. The preferred outer sheets for use in the absorbent articles of the present invention are selected from nonwoven, nonwoven sheets of anodine and sheet material of aperture formed films. The films formed with openings are especially preferred for top sheets because they are They are permeable to body fluids and have not yet appeared and have a reduced tendency to allow fluids to pass back through and rewet the user's skin. Therefore, the surface of the formed film that is in contact with the body remains dry, so that the body's soiling is reduced, and creating a more comfortable feeling for the user. Suitable shaped films are described in U.S. Patent No. 3,929,135 (Thompeon), issued 30 December Jfc 1975; U.S. Patent No. 4,324,246 (Mullape et al.), Issued April 13, 1982, U.S. Patent No. 4,342,314 (Radel et al.), Issued August 3, 1982; United States Patent No. 4,463,045 (Ahr and otroe), issued on July 31, 1984; and U.S. Patent No. 5,006,394 (Baird) issued April 9, 1991. Each of these patents is incorporated herein by reference. The top sheets of film formed with particularly preferred micro apertures are disclosed in U.S. Patent No. 4,609,518 (Curro et al), issued September 2, 1986, and the Patent. of the United States No. 4,629,643 (Curro et al.), Issued on December 16, 1986, which was incorporated by reference. The preferred top sheet for use in the catamenial products of the present invention is the formed film described in one or more of the above patents and marked on the sanitary napkins by Procter & Gamble Company of Cincinnati, Ohio as "DRI-WEAVE®". The body surface of the formed film top sheet can be hydrophilic in such a way that it helps body fluids transfer through the upper sheet faster than if the body surface were not hydrophilic to decrease the likelihood that fluid will flow out of the upper leaf instead of flowing inside. and being absorbed by the abeorbenie sculpture. In a preferred embodiment, the feneoaclive agent is incorporated in the polymeric materials of the topsheet the film formed as it is written in the United States Patent Application ^ fc with Serial Number 07 / 794,745"Article abeorbenie having a cover sheet with openings and non-woven" presented on November 19, 1991 by Aziz and others, which is incorporated herein by reference. Alimentarily, the surface of the body of the euperior sheet can be made hydrophilic by shaping it with a tensio-active agent as described above. describes in the above referenced U.S. 4,950,254, incorporated herein by reference. ^ fc F. Test Methods 1. Saline Fluid Conductivity This test determines the Saline Flux Conductance (CFS) of the layer of the gel layer formed from an abehorbenie polymer forming hydrogel, a mixture of hydrogel-forming polymers in neutralized form, or a composition of mixed hydrogel ion-exchange hydrogel (in what is referred to as a polymer that form hydrogel) that is inflated in Jayco urine and under a limit pressure. The objective of this test is to evaluate the ability of the layer of The hydrogel formed from the hydrogel-forming absorbent polymers for acquiring and distributing body fluids when the polymer is present in concentrated ally in an acidic member and exposed to mechanical pressures of use. The methods of Darcy's law and the flow of the eetationary state are used to determine the conductivity of the saline flow. (See, for example, "Absorbency" by P. K. Chatterjee, ^ fc Eleevier, in 1985, Page 42-43 and "Chemical Engineering Vol. II; Third Edition, J. M.

Couleon and J.F. Richardeon, Pergamon Preee, 1978, pages 125-127.) For the hydrogel-forming polymers in neutralized form, the hydrogel layer used for the CFS measurement is formed by swelling an absorbent polymer that forms hydrogel in Jayco synthetic urine for a period of time. 6 minufoe. The hydrogel layer is formed and the conductivity is measured under a limiting mechanical pressure of 0.3 pei ¿10 (about 2 kPa). The flow conductivity is measured using a 0.118M NaCl solution. For the hydrogel-forming absorbent polymers whose Jayco synthetic urine collection confers time sub-tropically has been leveled, this concentration of NaCl has been found to maintain the thickness of the hydrogel layer subsurfacely maintained during the measurement. For some polymeric and hydrogel-forming abeorbenis can small changes in the thickness of the hydrogel layer as a result of swelling of the polymer, deflation of the polymer, and / or changes in the porosity in the ^ fc hydrogei layer. A hydrosylic pressure of 4920 dynes / cm2 (5 cm of 0.118M NaCl) is used for the measurement. For polymer compositions that form mixed layer ion exchange hydrogel, the period of time for swelling Typically, it is extended to 225 minutes to allow more time for the sample to equilibrate and the NaCl composition is typically adjusted (generally at a lower concentration) so that only small changes in the thickness of the hydrogel layer during the measurement. The flow velocity is determined by measuring the amount of solution that flows through the hydrogel layer as a function of time. The amount of flow may vary over the duration of the measurement. The reasons for the variation of flow include change in the thickness of the hydrogel layer and change in the viscosity of the inter-fluid fluid, while the fluid initially preempts in the ineffective recesses (which, for example, may include dissolved exible polymer). it replaces with the NaCl solution. If the fluid velocity is time dependent, the initial flow rate obtained is typically used to calculate the flow conductance by extrapolating the measured flow rates to zero time. The saline flow velocity is calculated from the initial flow velocity, dimensions of the hydrogel layer, hydrostatic pressure. For seven minutes in which the flow velocity is eubstantially connected, a coefficient of permeability of the hydrogel layer can be calculated from the salinity flow conductivity and the viecoeidad of the NaCl solution. A suitable apparatus 610 for this test is shown in FIG. 7. This apparatus includes a hydrostatic head reservoir generally indicated as 612 which is e ected in a laboratory box generally indicated as 614. The reservoir 612 has a 616 cap with a vent. plugged indicated by 618 so you can adding additional fluid to reservoir 612. An open end tube 620 is inserted through cap 616 to allow air to enter reservoir 612 for the purpose of - ^^ release of fluid at a hydrostatic pressure consol. The bottom extruder "of the tube 620 is positioned such that fluid is maintained in the cylinder 634 at a height of 5 cm above the bottom of the hydrogel layer 668 (see Figure 8). The reservoir 612 is generally provided. with an L-shaped 622 release tube that has a 622a entanglement that is below the surface of the fluid in the reservoir.The release of the fluid through the tube 622 is confroled by the stopcock 626. The fluid 622 frees fluid from the reservoir 612 to a piston / cylinder assembly indicated generally as 628. Below the elange 628 there is a panlalla support (not moelrado) and a collection tank 630 that was on a laboratory balance 632.

Referring to Fig. 7, the assembly 628 basically consists of a cylinder 634, a ram indicated generally as 636 and a cover 637 provided with perforations for the piston 636 and the release tube 622. As shown in Fig. ^ Fc 7 , the outlet 622b of the tube 622 is placed below the lower end of the tube 620 and therefore it will also be below the surface of the fluid (not measured) in the cylinder 634. As shown in FIG. 8, the piston 636 consists of a generally cylindrical LEXAN® shaft 638 having a concentric cylindrical bore 640 drilled below the longifudinal axis of the tree. Both ends of the 638 tree are machined to provide 642 and 646 ends. A weight indicated as 648 looses on the 642 eximeum and has a 648a cylindrical bore drilled through ^ fc from the center of the year. A circular Leflon plunger head 650 having an annular depression is generally inserted on the other end 646 at its bottom. The tamper head 650 has its size so that it moves slidably inside the cylinder 634. As shown particularly in FIG. 9, the piston head 650 is provided with four concentric rings of twenty-one perforations each generally indicated, ^ fc 654, 656, 658, and 660. As can be seen in Figure 9, the concentric rings 654 to 660 fit within the area defined by the depression 652. The perforations in each of these concentric rings are bored from the superior to the bottom of the piston head 650. The perforations in each ring are spaced approximately by 15 degrees and offset by approximately 7.5 degrees from the perforations in the adjacent rings. The perforations in each ring have a progressively smaller diameter going inwardly from ring 654 (0.204 inch diamery, 0.518 cm) to ring 660 (0.111 inch diametre, 282 cm.). The head of skin 650 also has cylindrical perforation 662 drilled in the center of the previous one to receive the end 646 of the shaft 638.

As shown in Figure 8, an agglomerated circular glass disk 664 fits within the 652 tank. A non-stainless steel mesh pan. 400 is attached to the lower end of cylinder 634 which is biaxially tensioned before attaching. The mixed-jet filter of the absorbent polymers that form hydrogel indicated as 668 is supported on the screen 666. The cylinder 634 was drilled from a transparent LEXAN® rod or equivalent and has an internal diameter of 6.00 cm. (area = 28.27 cm2), a wall thickness of approximately 0.5 cm, and a height of approximately 6.0 cm. The piston head 650 was machined from a solid íphon rod. It has an allura of 0.625 inches (1.588 cm) and a diameter that is smoothly less than the diameter ^ fc inferno of the cylinder 634, of the form that fits denfro cylinder with the minimum evacuation of the walls, but still slides freely. The depression 652 is approximately 56 mm in diameter by 4 mm in depth. The perforation 662 in the head of the 650 head has a 0.625 inch aperture. (1588 cm) (18 roecae / inch, 18 threads / 2.54 cm) for the eximere 646 of the 638 tree. The agglomerated disk 664 is chosen by alia permeability (for example Chemglass Cal No. ^ fc CG-201-40, 60 mm diametre, thickness of poroeidad) and ee supports in such a way that fits comfortably within the depression 652 of the head of the piston 650, with the bottom of the disc being ejected by jet from the bottom of the head of the piston. The 638 eeta tree machined from a LEXAN® rod and has an outer diameter of 0.875 inch (2222 cm and an internal diameter of 0.250 inch 0.635 cm) The end 646 is approximately 0.5 inches long (1.27 cm long) and It is perforated to match the 662 hole in the piston head 650. The end 642 is approximately one inch long and 0.623 inches in diameter. (1.582 cm), forming an annular shoulder to support the weight of the 648 stainless steel. The fluid that flows through the perforation 640 in the shaft 638 can have direct access to the agglomerated die 664. The peg of the annular stainless steel 648 has a internal diameter of 0.625 inch (1.588 cm), so that it slides on the eximeum 642 of the tree 638 and descends on the annular shoulder formed there.The combined weight Jfc of the weight of the annular disc 664, piston 636 and the weight 648 = 596 g, which corresponds to a pressure of 0.3 psi (2.1 kPa) for an area of 28.27 cm2. The cover 637 was machined by LEXAN ® or its equivalent and has the dimensions to cover the upper part of the cylinder 364. It has an opening of 0.877 (2.228 cm) in the center of the anterior for the 638 tree of the 636 pieton and a second opening near the edge The cylinder 634 rests on a stainless steel support pan. ^ fc rigid mesh 16 (not shown) or equivalent. The support screen is eminently permeable in a way that does not impede the fluid from flowing into the collection tank 630. The support pan is generally used to support the cylinder 634 when the flow velocity of the saline solution through the eneamble 628 is larger than to the about 0.02 g / sec. For flow rates less than about 0.02 g / sec, it is preferable that it be a continuous fluid path between the cylinder 634 and the depoeite ^ fc collection. This can be complemented by replacing the support pan, the collection tank 630, the analytical balance 632 with the analytical balance 716, the tank 712 agglomerated funnel 718, and the reeoperating connection luboe and the aparaloe valve 710 (see Figure 10), and positioning cylinder 634, on the agglomerated disc in the agglomerated funnel 718. The Jayco synthetic urine used in this method is prepared by dissolving a mixture of 2.0 g of KCl, 2.0 g of Na 2 SO 4, 0.85. g of NH4H2PO4, 0.15 g of (NH4) 2 HPO4.0.19 g of CaCl2, and 0.23 g of MgCl2 in a water-thinned tube. 25 The 0.118 M solution of NaCl is prepared by dissolving 6,896 g of NaCl (Baker Analyzed Ragenl or equivalent) in one liter of distilled water.

An analytical balance 632 with a precision of 0.01 g (for example Meiíler PM4000 or equivalent) is typically used to measure the amount of fluid flowing at flow of the hydrogel layer 668 when the flow velocity is about 0.02 ^ g. / sec or greater. A more accurate balance (for example Meiler AE200 or equivalent) may be necessary for less permeable hydrogel layers that have lower flow rates. The balance is preferably interfaced with a computer to inspect the amount of fluid with time. The thickness of hydrogel layer 668 in cylinder 634 is measured to an accuracy of about 0.1 mm. You can use any method that has the .10 required precision, as long as the weights are not removed and the hydrogen layer? Q ^ fc is additionally compressed or disturbed during the measurement. It is acceptable to use a gauge measurement (eg Manostaí 15-100-500 or equivalent) to measure the vertical diet between the bottom of the 648 stainless steel weight and the top of the cover 637, relative to this disiancia without 668 hydrogel layer in cylinder 634. It is also The use of a depth measurement (for example Ono Sokki EG-225 or equivalent) to measure the piston position 636 or the weight of 648 stainless steel is acceptable.

Relative to any fixed surface, compared to its position without the hydrogel layer in cylinder 634. The CFS measurement is developed at ambient temperature (for example 20 of 20-25 ° C) and is carried out as follows: aliquot of 0.9 g of the hydrogel-forming absorbent polymer (which corresponds to a pee bae of 0.032 g / cm2) is added to the cylinder 634 and completely dissipates over the paphlala 666. For most of the hydrogel-forming absorbent polymers, the moisture content is typically less than 5%. Therefore, the amount of polymer that forms the hydrogel to be added can be determined in a bath (as it is) of wet weight. For hydrogel-forming abeebentee polymers having a moisture content greater than about 5%, the added polymer should be corrected for moisture (eg, the added polymer should be 0.9 g on a dry weight basis). ). Care is taken to prevent the absorbent polymer forming hydrogel from adhering to the walls of the cylinder. The foot 636 (minus weight 648) with the disk 664 placed in the depression 652 of the head of the 650th foot is inserted into the cylinder 634 and placed on top of the polymer forming hydrogel eeco 668. If necessary, the piston 636 can be rotated smoothly to more evenly distribute the hydrogel forming polymer that forms on the screen 666. The cylinder 634 then is covered with the cover 637 and the weight 648 then placed on the end 642 of! tree 638. An agglomerated disk (coarse or extra thick), having a diameter greater than cylinder 634 is placed in a wide / shallow flat bottom container that is filled to the top of the agglomerated disk with Jayco synthetic urine. The cylinder / piston assembly 628 is then placed on the upper part of the dielectric agglomerated glass. The fluid from the container passes through the agglomerated disc and is absorbed by the absorbent polymer that forms hydrogel 668. While the polymer absorbs the fluid, a layer of hydrogel is formed in the cylinder 634. After a period of time of 60 min , the thickness of the hydrogel layer is determined. Care is taken that the hydrogel layer does not lose fluid or take in air during this procedure. The piston / cylinder assembly 628 is then transferred to the apparatus 610. The support screen (not shown) and any other space is closed and the piston / cylinder assembly is pre-heated with ealine eolution. If the agglomerated funnel 718 of the PUP 710 apparatus is used to support the cylinder 634, the surface of the agglomerated funnel should be raised minimally relative to the fluid's filtrate in the collection tank, with valves between the agglomerated funnel and the collection tank. being in open poetry. (The elevation of the agglomerated funnel must be sufficient so that the fluid passing through the hydrogel layer does not accumulate in the funnel.) 5 The CFS measurement begins by adding NaCl solution through the perforation. 640 on the shaft 638 in order to issue air from the head of the piston 650 and then turn the stopcock 626 to an open position such that the release tube 622 releases fluid to the cylinder 634 at a height of 5.0 cm above the bottom of the hydrogel layer 668. Although it is considered that the measurement at 1P started (t0) at the time when the NaC solution! first it is added, it is not! The time at which an ascertainable hydrostatic pressure, corresponding to 5 cm of saline solution, is maintained at an eetable flow velocity (ts). (The time ts should typically be about one minute or less.) The amount of fluid that flows through the hydrogel layer 668 against time is determined gravimetrically over a period of time. time of 10 minutes. Once the elapsed time has elapsed, the piezo / cylinder 628 is removed and the thickness of the hydrogel layer 668 is measured. The change in the The thickness of the hydrogel layer is less than about 10%. In general, the flow velocity does not need to be contatanie. The speed of the fime-dependent flow through the system Fs (f) is determined in units of g / sec, dividing the incremental weight of the fluid that passes through the system (in grams) by the incremental time (in seconds). Only the data are collected for the same time and 10 minutes are used for flow rate calculations. The results of the flow velocity between e and 10 min ee are used to calculate a value for Fs (í = 0), the initial flow velocity through the hydrogel layer. Fs (t = 0) is calculated by exculpolating the results of a least squares fit of Fs (í) confers time to í = 0.

For a layer having a very high permeability (for example a flow velocity greater than about 2 g / sec), it can not be practiced to collect fluid for the entire 10 minute period. For higher speeds of Approximately 2g / sec, the collection time could be shortened in proportion to the flow speed. For some absorbent polymers that form hydrogel that have extremely low permeability, the formation of the fluid by the hydrogel completes the flow of fluid from the hydrogel layer and there is no flow of fluid through the hydrogel layer. and inside the depoeito or, possibly, there is an IO there. fluid airtime network made out of the PUP depoeiio. For eefae capae of . Excessive low permeability, it is optional to extend the time for the absorption of Jayco synthetic urine to longer periods (for example, 16 hours). In a separate measurement, the flow velocity through the apparatus 610 and the piston / cylinder 628 assembly (Fa) was measured as described above, except that the presence of a hydrogel layer is not present.

If Fa is much greater than the flow rate through the seventh when the hydrogel layer is present, Fs, then no correction is necessary for the flow resilience Jfc of the CFS aparate and the pieyón / cylinder eneamble. In this limit, Fg = Fs, where Fg is the distribution of the hydrogel layer at the flow rate of the seventh. However, if this requirement is not met, the correct correction is calculated to calculate the value of Fg from values of Fs and Fa: Fg = (Fa X Fß) / (Fa - Fs) The Saline Flow Conductivity (K) of the hydrogel layer is calculated using the following equation: K =. { Fg (l = 0) xLo} /. { pxAx? P } , Where Fg (f = 0) is the flow velocity in g / sec determined from the regression analysis of the flow velocities and any correction due to reelection to the flow of the beam / apparatus, L0 is the initial thickness of the hydrogel layer in cm, p is the deficiency of the NaCl solution in g / cm3. To the area of the hydrogel layer in cm2, the hydrodynamic pressure in dynes / cm2, and the saline flow conductivity, K, are in units of cm3 eeg / g. The average of three determinations must be reported. For hydrogel layers where the flow velocity is substantially constant, a coefficient of permeability (K) can be calculated from the salinity flow conductivity using the following equation:? = K?, Where? The viscosity of the NaCl solution in poiees and the coefficient of permeability, K, is in units of cm2. U.S. Patent No. 5,552,646 to Goldman and others for an example illustrating how the CFS calculates according to the present invention. 2. Performance Capacity Under Pressure (PUP) This test determines the gram / gram absorption of synthetic urine for an absorbent polymer that forms hydrogel, a mixture of hydrogel-forming polymers in a neutralized form to a polymer composition that form hydrogel ion exchange hydrogel. Mixed layer (in what is referred to as hydrogel forming polymer that is laterally limited in a piston / cylinder assembly under a limiting pressure (eg 0.3 psi (2.1 kPa), 0.7 psi (4.8 kPa), 1.4 psi (9.6 kPa) The objective of the test is to evaluate the ability of the absorbent polymer layer that forms a hydrogel to absorb fluid from the body, over a practical period of time (for example, 60 minutes and 225 minutes) when the polymer is preempted in the water. and combine concentrating on a reflecting member and exposing it to a pree eeion, then press it against a polymer that forms a hydrogel and forces it to bend. Orber urine against including mechanical preeionee that rejuvenate the user's weight and / or movements, press mechanics that result from the elastic and clamping systems, and from the hydroetic eduction that results from the adjacent capillary layers (for example fibrosae) and structures that is drained of fluid. The test fluid for the PUP capacity test was Jayco synthetic urine. This fluid is absorbed with absorbent polymers that form hydrogel on demand with hydrostatic pressure absorption conditions close to zero. A convenient apparatus 710 for this test is shown in FIG. 10. In one example of this apparatus is a fluid reservoir 712 (such as a Petri dish) that has a cover 714. The reservoir 712 rests on an analytical balance indicated generally. as 716. The exoteric apparatus of section 710 is an agglomerated funnel which is generally indicated as 718, a piston / cylinder assembly generally indicated as 720 which is adjusted to the funnel 718, and the cap of the agglomerated funnel of cylindrical plastic indicated generally as 722. which was on the funnel 718 and was open at the bottom and closed at the top, the upper part having a tiny hole. The apparatus 710 has a system for transporting the fluid either in the direction consisting of the sections of the capillary tube of the glass indicated as 724 and 731a, flexible plastic tube (for example Tygon tube of inch of internal diameter and 3/8 of inch of external diameters) indicated as 731b, eleemblee de llavee de paeo 726 and 738 and connectors of Teflon 748, 750 and 752 to connect the glass tubes 724 and 731a and the assemblies of valves 726 and 738. The key assembly in step 726 comprises a three-way valve 728, glass capillary tube 730 and 734 in the main fluid system and a section of glass capillary tube 732 for refilling the depoeite 712 and ejecting jet through the agglomerated disk in the agglomerated funnel 718. The tap wrench assembly 738 similarly connects a fres rail valve 740, glass capillary tubes 742 and 746 in the main fluid line, and a section of glass capillary tube 744 that acts to like a drain for the seventh. Referring to Figure 11 the eneamble 720 consists of a cylinder 744, a piston-shaped fc ^ fc indicated by 756 and a weight 758 that fits across the bottom of the foot. 753. Attached to the lower end of cylinder 754 is a pan 755 that wears the stainless steel mesh no. 400 that is extended biaxalmenfe to extend antee to attach. The hydrogel-forming polymers are indicated generally as 760 on the 759 screen. The cylinder 754 eeta drilled by a LEXAN ® rod (or equivalent) traneparenle and has an inferno diameter of 6.00 cm (area = 28.27 cm2), with a wall thickness of approximately 5 mm and a height of approximately 5 ^ fc cm. The piston 756 is in the form of a Teflon cup and is machined to fit inside the cylinder 754 with angoeta íoleranciae. The cylindrical stainless steel peg 758 is easy to fit into the 752 pieton and fits with a handle on the top (not shown) for ease of removal. For a pressure limit of 0.7 psi (4.8 kPa), the combined weight of the pieton 756 and the pee 758 ee 1390 g, which corresponds to a pressure of 0.7 pei (4.8 kPa) for an area of 28.27 cm2. The components of the apparatus 710 are sized in such a way that the flow velocity of the eintélica urine to the previous one, under an electroelalic head of 10 cm, at the time is 0.01 g / cm2 / sec, where the eetá flow velocity normalized by the area of the agglomerated funnel 718. Particularly impacific factors in the flow velocity are the permeability of the agglomerated die in the agglomerated funnel 718 and the internal diameters of the glass tube 724, 730, 742, 746 and 731 and the key of lae valve 728 and 740. The deposit 712 is placed on an analytical balance 716 which is requires at least 0.01 g with a current of less than 0.1 g / hr. The scale is preferably inferred from a software compiler that can (i) inspect the weight change in the balance at pre-established time intervals from the initiation of the PUP test and (ii) be adjusted to the start in a change of peeo of 0.01-0.05 g, depending on the balance's sensitivity. The capillary tube 724 that enters the reservoir 712 should not be in contact with either the bottom of the anio or the cover 714. The volume of the fluid (not moled) in the reservoir 712 should be sufficient in such a way that the air is not extract in capillary tubes 724 during measurement. The fluid level in the deposited 712, at the initiation of the measurement, approximately must be 2 mm. below the surface of the agglomerated disc in the agglomerated funnel 718. This can be confirmed by placing a small gout of fluid in the agglomerated die and that it inspects gravimemporaneously its slow flow back to reservoir 712. This level should not change significantly when the piston / cylinder assembly 720 is positioned within the funnel 718. The deposit must have a sufficiently long diameter (for example approximately 14 cm) so that removal of the approximately 40 ml portions results in a change in the height of the Menoe fluid of 3 mm. Before measurement, the assembly is filled with Jayco synthetic urine. The agglomerated disk in the agglomerated funnel 718 is jetted out as it is filled with fresh sinfellic urine. For possible extension, water bubbles are removed from the bottom surface of the agglomerated die and the system that connects the funnel to the reservoir. In the following procedures, they were carried out by sequential operation of fres viae stopcocks: 1. The excess of fluid is removed on the euperiorie surface of the agglomerated die of the agglomerated funnel 718. 2.- The peeo / alíura of the eolución of the 712 tank is set to its own value / level. 3. - The agglomerated funnel 718 is placed at the straight line relative to the deposit 712. 4.- The agglomerated funnel 718 is then covered with the cover of the agglomerated funnel 722. 5 5.- The deposit 712 and the agglomerated funnel 718 eetán equilibradoe with valve 728 and 740 of the keypads 726 and 738 in the open connection position. 6.- The valves 728 and 740 are then closed. 7. The valve 740 then rotates in such a way that the funnel is open to the drainage tube 744. ^ fc 8. The system is allowed to equilibrate in that position for 5 min. 9. The valve 740 then returns to closed supposition. Paeoe numbers 7-9 temporarily "eecan" the surface of the funnel agglomerator 718 exposing it to a small hydrostatic euction of approximately 5 cm. This suction is applied if the open extruder of tube 744 extends ^^ approximately 5 cm below the level of the agglomerated disk in the agglomerated funnel 718 and filled with synthetic urine. Typically, approximately 0.2 g of fluid is drained from the system during this procedure. This procedure prevents the premature absorption of synthetic urine when the piston / cylinder assembly 720 is positioned within the agglomerated funnel 718. The amount of fluid that is drained from the agglomerated funnel in this process (so-called agglomerate funnel correction weight) is measured by driving the PUP test (see below) for a period of 15 minutes without the piston / cylinder 720 assembly. Essentially the fluid drained from the agglomerated funnel by this process is reabsorbed very quickly by the funnel when the test is started. Therefore, it is necessary to draw the correction weight of the weights of the fluid removed from the reservoir during the PUP test (see below). It is added to the cylinder 754 0.9g of absorbent polymer that forms hydrogell Jfc 760 (corresponding to a base weight of 0.032 g / cm2) and that dissolves on the panlalla 759. For most hydrogel-forming absorbent polymers, the moisture content is typically less than 5%. For those polymers, the weight of added polymer can be determined in a small amount (as ee). For polymers having a moisture content greater than 5%, the weight of the added polymer should be corrected for moisture (for example, the added polymer should be 0.9 g on a 1 Q basis dry weight). Attention is paid to prevent the absorbent polymer forming JFC hydrogel 760 adheres to the bottom walls of the cylinder 754. The piston 756 moves from the cylinder 754 and is placed on the surface of the absorbent polymer forming hydrogel 760. The piston can be rotated smoothly to assist in the distribution of the absorbent polymer. which forms hydrogel. The 720 piston / cylinder assembly has been placed in the upper part of the first portion of the funnel 718, the peg 758 is displaced in the piston 756, and the upper part of the funnel 718 is then covered with the cover of the ^ fc agglomerated funnel 722. After the balance reader has been revised for the spiking, the test is started by opening valves 728 and 740 to connect funnel 718 and reservoir 712. With self-initiation, the collection of daioe begins Immediately, while the funnel 718 begins to reabsorb the fluid. The data is recorded as a function of time for a period of time of 225 minutes. The moisture content of the polymer abeorbenie that forms hydrogel is separated from the product by measuring the percentage of weight lost after 3 hr @ 105 ° C. The measured moisture content is used to calculate the dry weight of the hydrogel-forming polymer used in the PUP test.

Capacity PUP (g / g; t) = (Wr (t = 0) - Wr (í) - Wfc) / (Whfap; dry basis) Where Wr (í = 0) is the weight in grams of deposit 712 before the initiation. Wr (t) is the weight in grams of the tank in the time elapsed (for example 60 min or 225 Jfc min), WfC is the correction of peeo in grams of the agglomerated funnel (measured separately), and Whfap; Dry base is the dry weight in grams of the polymer abeorbenie that forms hydrogel. 3. Poroeidad of the Hydrogel Layer (PCH) The test determines the porosity of the hydrogel layer (PCH) formed from an absorbent polymer that forms hydrogel, a mixture of polymers that They form hydrogel in a neutralised form or a composition of polymer that form a mixed-exchange ion exchange hydrogel (hereinafter referred to as a hydrogel-forming polymer) that is swollen by Jayco synthetic urine under a limiting pressure. The objective of this test is to evaluate the ability of the formed hydrogel layer from polymere abeorbeníee forming hydrogel to remain poroea when the polymer eetán present in alias concentrations in an absorbent member and fl exposed to mechanical pressures of use. The PCH is the fractional volume of the layer that is not occupied by hydrogel. An excluded volume method is used to measure PCH under a limiting pressure. 20 The PCH is measured using a modified version of the piston / cylinder apparatus used in the CFS method. The 0.118 M NaCl solution in the CFS method is modified to measure the PCH by dissolving a Blue Dexire polymer of molecular weight in a sufficient amount such that the ultrasound yields an optical abeorbancia of about 0.8 unidadee de abeorbancia in the maximum polymer absorption of about 617 nm. The molecular weight of the Blue Dextran polymer is sufficiently high such that the polymer is excluded from the hydrogel. The hydrogel layer of the shape and poroeity is measured under a mechanical limit pressure of 0.3 psi (about 2 kPa). The hydrogel layer used for the measurement of PCH is formed Jfc swelling approximately 0.9 of an absorbent polymer that forms hydrogel in the Piston device / PCH cylinder with urine and urine for a period of time of around 60 minutes. At the end of that period, the thickness of the hydrogel layer is deferred. The fluid content in the inverse of the hydrogel layer is exchanged with the 0.118 M NaCl solution containing Blue Dextran (SBDS) by flowing an excess of the SBDS (optical absorbance equal to A,) through the hydrogel layer subject JO at a low hydrostatic pressure. For an absorbent polymer that forms a hydrogel whose When the time of the level is reached, the NaCl concentration of SBDS has been found to maintain the thickness of the hydrogel layer substantially co-extensive during the exchange step. For some abeerobeníee polymers that form hydrogel, small changes in the groeor may occur as a result of the swelling or deehinchazón. The flow of SBDS through the continuous hydrogel layer has meant that the exchange is complete. When the flow of SBDS is stopped, any excess of SBDS tffc either above or below the hydrogel layer is allowed to be drained or removed in some other way. The inlersficioe denlro of the hydrogel layer remain fully ealuradoe with SBDS. The groeor of the hydrogel layer (t) ee re-measure (tf) and multiply by the area of the cylinder (Ac) to obtain the volume of the hydrogel layer (Vhg?). The content of SBDS in the interstices within the hydrogel layer is then jetted using an excess of 0.118 M NaCl solution (SS) and collected quantitatively. The jet ejection with SS is continuous and essentially all the Blue Dexfran is extracted from the hydrogel layer. The volume of the The collected solution containing the Blue Dextran (Vf) is determined either volumetrically or gravimetrically and is measured by optical aberration (Af). the volume of the samples (Vv) is determined from the values of Vf, A, and Af. The value of Vv is divided by Vhg? to determine the porosity of the hydrogel layer. A piston / cylinder apparatus suitable for the test sample in FIG. 12 and is similar to the piston / cylinder apparatus shown in FIG. 8. Referring to FIG. 12, the apparatus 828 basically consists of a cylinder 834, a piston. generally indicated as 836 and a cover 837 provided with perforations for the piston 836 and release / removal of the solution (not shown). As shown in Figure 12, the piston 836 consists of a cylindrical LEXAN® shaft having a concentric cylindrical bore 840 drilled below the longitudinal axis of the shaft. Both ends of the shaft 838 are machined to provide the ends 842 and 846. A weight indicated as 848 is located on the end 842 and has a cylindrical bore 848a drilled through the center of the previous one. A generally circular pto head is inserted over the outer ear 846. The ridge head 850 has its size to move slidably inside the cylinder 834. As shown particularly in FIG. 13, the piston head 850 is provided with inner and outer concentric rings that contain both anvil and ^ fc fourteen cylindrical perforations of approximately 0.375 inches (0.953 cm), reepeclivamenle, indicated generally by arrows 860 and 854. The perforations in each of these concentric rings are drilled from the The lower part of the head of the 850-ft. Head is also pierced with a cylindrical perforation 862 drilled in the anterior chamber to receive the 846 ex trem of the 838 shaft. Attached to the lower end of the cylinder 834 is a screen dressed in No. 400 stainless steel mesh that is biaxially ejected to remove it before the fixation. Attached to the lower end of the foot of the foot 850 is a stainless steel mesh pandemic No. 400 which is biaxially removed to remove it before fixing. The sample of the hydrogel-forming polymer Abeorbenfe indicated as 686ee is supported on the screen 866. The cylinder 834 is drilled by a translucent LEXAN® rod or equivalent and has an internal diameter of 6.00 cm (area = 28.27 cm2), a wall thickness 5 of approximately 0.5 cm, and an ally of approximately 6.0 cm. The piston head 850 is machined from a LEXAN® rod. It has an ally of approximately 0.625 and a diameter size so that it fits within the cylinder minimal wall evacuations, but it still freezes freely. Drilling 862 at the top of the 850 foot head is rounded 0.625 inch aperture 1.0 (1.588 cm) (18 roecas / inch, 18 threads / 2.54 cm) for the 846 exfrem of the 838 tree.

Jfc 838 shaft is machined by a LEXAN® rod and has an external diameter of 0.875 inches (2222 cm) and an internal diameter of 0.250 inches (0.635 cm). The extrude 846 is approximately 0.5 inch (1.27 cm) long and is threaded to the set of the perforation 862 at the head of the 850 pointer. The end 842 is approximately one inches long (2.54 cm) and 0.623 inches in diameter (1,582 cm), which forms an angular shoulder to support the weight of 848 stainless steel. The fluid that passes to ? Through the perforation 840 in the shaft 838 it can be directed to have access to the pamphlet 864. The annular weight of stainless steel 848 has an internal diameter of 0.625 inches (1.588 cm) in the manner that it moves from the end 842 of the shaft 838 and deecansa on the ring shoulder there formed. The combined weight of piston 836 and weight 848 is approximately equal to 596 g, which corre- sponds to a pressure of 0.3 psi (2.1 kPa) for an area of 28.27 cm2. The cover 837 is machined by LEXAN® or equivalent eu and is dimensioned to cover the top of the cylinder 834. It has an opening of 0.877 inches (2228 cm) in the foreground of the former for the 838 shaft of the pieton 836 and a second opening near the edge of the anterior for the release / removal of the eolith.

When the solutions flow through the piston / cylinder apparatus, the cylinder 834 generally rests on a support screen of the stiff stainless steel mesh 16 (non-mosirado) or equivalent. A specilometer capable of measuring the optical absorbance at 617 nm with an accuracy of at least 0.001 absorbance units (for example Bausch &Lomb Spectronic 21 or equivalent) is used for the measurement of optical abeorbance. The optical abeorbance ee measures at a minimum value of 0.001 unidadee de abeorbancia, relative to a NaCl reference solution at 0.118 M. A Blue Dextran polymer having an average molecular weight of about 2,000,000 (Sigma, ca, no. D5376 or equivalent) is used for the measurement. A solution of 0.118 M NaCl (SS) is prepared by dissolving 6,896 g of NaCl ((Baker Analyzed Ragent or equivalent) in a liter of distilled water.Evalue in the solution is a sufficient amount of Blue Dextran to give an optical abeorbancia around of 0.8 absorbance unit (typically around 0.1% weight) The optical absorbance (A /) of the ealine eXin of Blue Dexfran (SBDS) is determined relative to a NaCl reference solution at 0.118 M. The thickness of the Hydrogel layer 868 in cylinder 834 is measured with an accuracy of at least about 0.1 mm Any method having the required accuracy may be used, as long as the weights are not removed and the hydrogel layer is not additionally compressed or disfurred It is acceptable to use a gauge size (for example Handshake 15-100-500 or equivalent) to measure the vertical distance between the bottom of the 848 stainless steel weight and the top of the cover 837, relative to this distance without hydrogel layer 868 in cylinder 834. It is also acceptable to use a depth measurement (for example Ono Sokki EG-225 or equivalent) to measure piston position 836 or weight of stainless steel 848 Relative to any fixed surface, compared to its pore in the hydrogel layer in cylinder 834. An analytical balance with an accuracy of at least 0.001 g (for example, Meiíler AE200) is used to determine the weight of the hydrogel-forming polymer. 5 The PCH measurement is performed at ambient temperature (for example 20-25 ° C) and is carried out as follows: An aliquot of 0.9 g of the absorbent polymer that forms a hydrogel (corresponding to a base weight of 0.032 g / kg). cm2) is added to cylinder 834 and completely discharged on panlalla 866. For most of the polymeric absorbers • 10 which form hydrogel, the moisture content is typically less than 5%. Therefore, The amount of absorbent polymer that forms hydrogel to be added can be determined in a wet (as ee) bath. For hydrogel forming abeorbene polymers having a moisture content greater than about 5%, the added polymer weight ee must be corrected for moisture (for example, the added polymer should be 0.9 g on a weight basis). dry). Care is taken to prevent the absorbent polymer forming hydrogel from adhering to the walls of the cylinder. The piston 836 (minus weight 848) is inserted into the cylinder 834 and placed on top of the absorbent polymer that forms dry hydrogel 868. If necessary, the foot 836 can be rotated euavemely to more evenly distribute the absorbent polymer The hydrogel forms on the panlalla 866. The cylinder 834 then is covered with the cover 637 and the weight 648 is then placed on the end 642 of the shaft 838. An agglomerated disk (coarse or extra thick), having a larger diameter than the cylinder 834 is placed in a wide / shallow flat bottom container 25 which is filled to the top of the agglomerated disk with Jayco synthetic urine. The 828 cylinder / foot assembly is then placed in the upper part of this agglomerated glass block. Fluid from the container passes through the agglomerated disc and is absorbed by the absorbent polymer forming hydrogel 868. While the polymer absorbs the fluid, a layer of hydrogel is formed in the cylinder 834. After JFC a period of 60 min, the thickness of the hydrogel layer is determined. It gets Be careful that the hydrogel layer does not lose fluid or take in air during this procedure. In 828 piston / cylinder assembly then place on a stainless steel rigid mesh support pan. The SBDS is added to the cylinder 834 through the fluid release period (not shown) in the cylinder cover 837 and ee Q. It allows you to move from the head of foot 850 and hydrogel layer 868, existing in the cylinder through the cylinder panicula 866. A convenient apparatus for the release of SBDS from the cylinder and which maintains a low hydroelectric connection but low (for example, above 5 cm of water) is the release device for the hydrostatic head shown in Figure 7 (reference numerals 612 and 626). The solution 5 existing through the cylinder screen 866 is periodically flashed and its optical absorbance is measured. The flow of SBDS continues until the exchange of the original solution contained in the interelicioe in layer 868 was essentially completed, as indicated by the existing solution having an optical absorbance approximately equal to that of the SBDS (for example within about 0.001 units 0 of absorbance). Typically, the total volume of SBDS used in this step is approximately 10 * Vhg ?. Then the addition of SBDS and the SBDS exceeding above the piston head 850 and within the cylindrical bores 854 and 860 at the head of the piston 850 is allowed to drain through the hydrogel layer 868 and out of the cylinder 834 through the cylinder screen 866. The thickness of the hydrogel layer (ff) is then re-measured. Finally, all residual solution remaining above the head of the 850 ridge, apart from the cylindrical perforations 854 and 860 in the head of the piston 850, or below the cylinder screen 866 that drains spontaneously, is oir way removed (for example, using a disposable pipette) minimizing any dissolution to the hydrogel layer. The volume (Vr) of ^ fc any SBDS that remains in the space between the piston head 850 and the cylinder 834 is estimated to be geomorphically (for example, the fractional area (Fa) of the space between the foot of the 850 head and the infernal wall of the cylinder 834 which is filled with SBDS multiplied by the calculated volume (Vg) between the head of the foot and the cylinder wall). The intersits within the 868 hydrogel layer must be kept completely saturated with SBDS. 828 Pipe / Cylinder Assembly 1 Q reattached, as necessary, on the panial support of the rigid steel mesh Then the SS is added to the cylinder 834 through the release / rejection hole (not shown) in the cylinder cover 837 and allow it to flow through the pisfon head 850 and the hydrogel layer 868. The excellent solution in the cylinder 834 at the end of the panfalla of the cylinder 866 is collectably collected in this one. step. A convenient apparatus for releasing SS to the cylinder and maintaining a consistent pressure but low hydrostatic pressure of SS (for example above around ^ fc of 5 cm of water) is the apparatus for releasing the hydrosylic head shown in figure 7 (reference numbers 612 through 626). Optionally, the weight 848, the cylinder cover 837 and the pisfón 836 can be removed just before the step of SS exchange (without removing the polymer that forms hydrogel or SBDS) to facilitate access and remove the Blue Dexlran contained in the interstices deníro of the hydrogel layer. The existing solution through the cylinder panfalla 866 is periodically sampled and its optical absorbance measured. The addition of coninuous SS makes the Blue's jet exudation Dexterized in the inlerslicioe deníro of the layer of Hydrogel 868 is essentially completed, as indicated by the above-mentioned solution, which has an optical abeorbance approximately equal to zero (for example, less than about 0.001 absorbance units). Typically, the ionic volume of SS used in this step is approximately 10 * Vhgl. The use of excess SS should be avoided, because it can be resolved in an excessive dilution of the Blue Dexíran. The volume of the solution collected in this step (Vf) is determined either gravimenely or volumetrically. After mixing, the optical absorbance (Af) of this final solution is measured. For a hydrogel layer which has a very high permeability, a hydroelastic low-stage preemption is typically used as a step (eg, pipetting) to control the flow rate and allow periodic grinding. For some absorbent polymers that form hydroge! (for example, those with extremely low permeability), the absorption of the Jayco solution by the hydrogel could not be destabilized after one hour and therefore additional fluid could be absorbed during the solution exchange steps. For these hydrogel-forming polymers, it is optional to extend the time for the absorption of the Jayco solution to wholesale periods (for example 16 hours). For hydrogel coatings that have very low permeability, they may require long periods of time for the solution exchange pads. If the thickness of the hydrogel layer changes as a result of the SBDS exchange step by more than 10%, the concentration of NaCl in the solution will need to adjust appropriately to reduce the extent of the change in thickness. It is likely to be particularly necessary for a mixed layer ion exchange hydrogel composition where the ion exchange impacts the interstitial concentration of the dissolved electrofolyl. The size exclusion polymer used by this method should not be appreciably increased by the hydrogel. For example, the polymeric cationic material, mixtures of hydrogel-forming polymers in neutralized form containing cationic polymers, and polymer compositions forming mixed-jet hydrogel (for example a high-molecular-weight Dexyran) and / or the use of an alternative method (for example chromatography) to determine the relative solution concentrations of the size exclusion polymer. Vv and PCH are calculated using the following formula: Vv = Vf * Af / A¡ - Vr PCH = VvA / hg? The average of the menoe doe delerminacionee must be reported. U.S. Patent No. 5,552,646 to Goldman et al. For an example illustrating how the PCH is calculated in accordance with the present invention. 4. Gel Volume For most absorbent polymers that form anionic hydrogel, the volume of the gel should be determined by the method described in Reissue US Pat. No. 32,649 (Brandt et al.), Reissued on April 19, 1988. (here incorporated by reference) but using synthetic urine Jayco. The volume of the gel is calculated on a dry basis weight. The dry weight used in the calculation of the gel volume is determined by drying the hydrogel-forming absorbent polymers at 105 ° C for three hours in the oven. In an alternative method for measuring the volume of gel that can be used for the absorbent polymers that form hydrogel that Abeorben Blue Dexíran to the surface of the formed hydrogel (for example, cationic polymers and hydrogel form). For this hydrogel-forming polymer, the Absorbance Capacity test is used, but the low weight of the hydrogel-forming polymers is used in the calculation instead of the weight as it is. See U.S. Patent No. 5,124,188 (Roe and oíroe) issued June 23, 1992, lae columnae 27-28 (herein incorporated by reference) for the description of the Absorbency Capacity test. For the polymers that form hydrogel in their neutralised forms, it is possible to modify the above method for its in-siiu neuirization in order to measure the gel volume of the hydrogel-forming polymer after neutralization. In this modified process, a stoichiometric amount of either NaCl or HCl (for example, Baker Analyzed Ragenl 1.0 M) is added to the Jayco syn spele urine to partially neutralize the hydrogel forming polymer (for example about 75%). to 100%). Gentle agitation is used to facilitate agitation. For the Blue Dextran method, the added volume must be minimized, both test and reference solutions need to be similarly brought, and the measured optical absorbances need to be corrected appropriately by change in the volume of the solution.

. Gel Resistance The gel strength or cutting modulus of the formed hydrogel is determined using the Gei Resistance / Cutting Module Determination method described in Reissued Patent No. 32,649, with the following modifications: (i) ) the hydrogel-forming absorbent polymer swells in Jayco hydroxy eyelid urine, (ii) an oscillator rheometer is used having a parallel plate configuration, where the space is set at 1.0 mm, (iii) the formula for calculating the cutting module is modified for the above parallel plate configuration, (v) the distension amplitude is less than about 0.3%, and (v) the polymers that form hydrogel are grounded (for example to pass to through a US Standard Test Strip No. 45 (openings of 350 microns)), if necessary, then the hydrogel packages formed at a high load factor encircle the plates of the oscillating rheometer. Jayco synthetic urine is added to the hydrogel forming polymers in a non-nebulized form with a skeletal content of either NaOH or HCl (for example 1. Baker Analyzed Rageni of 1 M or equivalent) sufficient to neutralize the polymer less partially. that forms hydrogel (for example, from around 75% to 100%). 6. Exfraibles The percentage of the polymer removable in polymere that form hidrogel baeadoe in carboxylic acid is determined by the method of Determination of 10. Exíraible Polymer Content - Polymeric Forming Hydrogel Baad in Acid Carboxylic acid described in United States Reissue Patent No. 32,649 (Brand and others), reissued on April 19, 1988 (incorporated herein by reference), but using 0. 9% ealine solution, filtering the supernatant through a 0.7 micron GF / F glass microfiber filter (eg Catalog # 1825-125) or equivalent, and calculate the polymer exirables on a dry basis. Also note in the Reissued Patent of loe United States No. 32,649 that Va should refer to the base volume and Vb should be ^^ refer to the volume of the acid. The percentage of the extractable polymer in hydrogel-based absorbent polymers based on non-carboxylic acid (eg, absorbent polymers that form cationic hydrogels of strong base or weak base and absorbent polymers that form anionic hydrogels of strong acid) is determined by the method of gravimetric / finely divided water Determination of the Exíraible Polymer Content - Polymers that Form Hydrogel that Confide Sulfonic Acid as decribed in the referenced Reissued Patent of United States 32,649, but calculating the exible polymer on a bae eeca.

For non-neutralized hydrogel-forming polymers such as those formed in a composite of mixed-form ion exchange hydrogel polymers, in-eil neutralization is used to convert the non-neutralized hydrogel-forming polymer to its partially neutralized form. In this procedure, a stoichiometric amount of either NaOH or HCl (for example Baker Analyzed Ragent of 1.0 M) sufficient to at least partially neutralize the polymer forming hydrogel (for example from about 75% to 100%) is added to the 0.9% saline solution.

Claims (15)

1. CLAIMS 1. A composition of exchange hydrogel-forming polymer Ionic ion of mixed stratum comprising one or more cationic polymers forming 5 ion exchange hydrogel and one more ion exchange hydrogel forming anionic polymers, characterized in that the mixed-ion hydrogel-forming hydrogel polymer composition exhibits increased Preemption Performance (PUP) capacity relative to a comparable polymer mixture. The cationic and anionic hydrogel-forming elements make up each of them, each of which is menoe 10 Neutralize to 70%. The composition of mixed-ionic ion exchange hydrogel-forming polymer, according to claim 1, having a PUP capacity of at least 20%, more preferably at least 50% more, more preferably at menoe 100% more, than the PUP capacity of the comparable mixture 15 of cationic and anionic polymers forming hydrogel constifuyentee, each of which is at least 70% neutralized. ^^ 3. The composite mixed ion exchange hydrogel-forming polymer composition according to claim 1 or 2, characterized in that the PUP capacity is measured after 225 minutes. 4. The mixed strand ion-exchange hydrogel-forming polymer composition according to claim 1 or 2, characterized in that the PUP capacity is measured after 60 min. 5. The hydrogel-forming polymer composition for mixed exchange, in accordance with claim 1 or 2, characterized in that 25 PUP capacity is measured under a confinement pressure of 0.7 pei. 6. The mixed-ionic hydrogel-forming polymer composition is of mixed form, according to claim 1 or 2, characterized in that the PUP capacity is measured under a confining pressure of 1.4 pei. 7. A mixed-jet ion exchange hydrogel-forming polymer composition comprising one or more cationic ion-exchange hydrogel-forming polymers and one more anionic ion-exchange hydrogel-forming polymers, characterized in that the composition has any of ( i) a PUP capacity in 225 minutes of at least 25 g / g, preferably at least 28 g / g, more preferably at least 33 g / g, under a confining pressure of 0.7 psi; or (ii) a PUP capacity in 60 minutes of at least 25 g / g, preferably at least 28 g / g under a confining pressure of 0.7 psi. 8. A composite of mixed-jet ion exchange hydrogel-forming polymer comprising one or more cationic ion-exchange hydrogel-forming polymers and one or more anionic ion-exchange hydrogel-forming polymers, characterized in that the composition has a capacity of PUP in 225 minima of at least 20 g / g, preferably at least 23 g / g, more preferably at least 26 g / g, under a confining pressure of 1.4 psi. 9. The mixed-ion-exchange hydrogel-forming polymer composition according to any of claims 1 to 8, characterized in that the cationic polymer or ion exchange-forming hydrogel polymers have an anion exchange capacity of less 6 meq / g, preferably 10 meq / g, preferably at least 15 meq / g. 10. The composition of the ionic exchange hydrogel-forming polymer of the mixed medium, according to any of claims 1 to 9, characterized in that the cationic ion-exchange hydrogel-forming polymer or polymers are selected from the group which polydimethylallylammonium hydroxide, polydimethylaminoethylacrylate, polydimethylaminoethylmelacrylate, and derivative and mixtures thereof. 11. The mixed-ionic ion-exchange hydrogel-forming polymer composition according to any of claims 1 to 10, 5 characterized in that ion exchange hydrogel-forming anionic polymer is selected from the group consisting of polyacrylic acid, polymaleic anhydride copolymers, and derivatives and mixtures thereof. 12. A member for the containment of body fluid, which comprises at least one region comprising a composition. 10 of mixed layer ion exchange hydrogel-forming polymer of any of ^ fc claims 1 to 11. The absorbent member according to claim 12, characterized in that the region comprises from 60 to 100%, preferably from 70 to 100%, more preferably from 80 to 100%, of the composition. 14. An absorbent article comprising a fluid-permeable topsheet, a downstream sheet and an absorbent core positioned between the top sheet and the sheet of paper, characterized in that the abehorbenite core comprises the absorbent member of claim 13 or 14. 15. The absorbent article according to claim 14, the 20 which is a diaper.