MXPA00000035A - Disposable absorbent articles with improved skin dryness performance and with improved core and chassis backsheet breathabilities - Google Patents

Abstract

A disposable absorbent article aiming at improved skin aeration by combining the benefits of an absorbent core providing good rewet performance and of using backsheet materials, which where covering the core area, provide vapour permeability, and which have even higher vapour permeability in the chassis region(s) surrounding the core region.

Description

DISPOSABLE ABSORBING ITEMS WITH FUNCTIONING OF DRY SKIN IMPROVED AND IMPROVED BREATHING OF THE BACKGROUND OF THE NUCLEUS AND CHASSIS FIELD OF THE INVENTION The present invention relates to disposable absorbent articles such as diapers, incontinence articles, sanitary napkins, training pants and the like, and in particular to articles having superior liquid handling performance in combination with improved ventilation of the skin. , such as by the operation of the improved breathability of the backsheet.

BACKGROUND OF THE INVENTION Absorbent, disposable articles, such as diapers, incontinence articles, sanitary napkins, trainers and the like are well known in the art. Typically, the disposable absorbent articles comprise a liquid permeable topsheet facing the wearer's body, a backsheet impervious to the liquid facing the wearer's clothing, an absorbent core disposed between the liquid permeable topsheet and the backsheet , and members to maintain the core in a fixed relationship to the user's body. In order to receive exudates from the body such as urine, feces and menstrual fluids, the item has to cover certain parts of the user's body. Generally, current items protect even larger parts of the user's body to allow for adequate storage of exudates. Although this protection is an essential element of the functionality of the article, the article can also, beyond impacting on the user's comfort, induce negative impact on the skin, such as by exerting pressure on the skin, or creating obstruction for certain parts of the skin, thus potentially inducing over-hydration of the skin, in particular under conditions where the user has a tendency to sweat. Numerous attempts have been reported that help in improving the skin condition of the user by allowing excess hydration to dehydrate to an acceptable level allowing either the air to reach the skin thereby reducing the potential effects of clogging, and / or by the water vapor that is removed from the surface of the skin. Generally, these mechanisms are referred to as "breathability" or "vapor or moisture permeability". A number of such applications help feminine hygiene products, such as catamenial products or so-called "protective pantyhose" as described in European Patent EP-A-0,104,906; European Patent EP-A-0,171,041; European Patent EP-A-0.710.471. These products generally have relatively low fluid storage capacity when compared for example to baby diapers or adult incontinence products, which are often designed for theoretical capabilities that significantly exceed the products for feminine hygiene. These respirable materials may be various types of wefts, such as films, which were made permeable to air / steam by drilling as described in U.S. Patent No. 5,628,737, or by exploiting the "microporosity" property as described. in European Patent EP-A-0 238 200; European Patent EP-A-0 288 021; European Patent EP-A-0 352 802; European Patent EP-A-0515501; U.S. Patent No. 4,713,068, whereby small gaps are created within the film similar to very small cracks. The international publication WO 94/23107; the international publication WO 94/28224; U.S. Patent No. 4,758,239; European Patent EP-A-0 315 013, all disclose alternate breathable materials which may be a fibrous textile or nonwoven webs, with air / vapor penetration easily through the relatively large pores of the structure. These frames that are, either, treated or untreated with respect to the improvement of its liquid impermeability properties, as described in European Patent EP-A-0 196 654. In the international publication WO 95/16562 a laminate of a non-recyclable material is disclosed. woven with a breathable film. Additional disclosures such as in international publication WO 95/16746 relate to other materials that allow water molecules to diffuse therethrough. Also, different material combinations comprising several layers of the above elements are also well known. Generally, all materials exhibit some exchange of gas permeability and impermeability to liquid. This becomes particularly clear when observing the pore size of a certain material, whereby an increase will allow easier penetration of the gas, but also easier penetration of the liquid. The latter may be undesirable, in particular when these materials are used to protect the retention regions of the liquid, such as in the core region. In particular for items designed to receive higher amounts of liquids, such as baby diapers or for adult incontinence, other approaches were helping to maintain only part of the breathable article, such as covering the liquid-absorbing portions (often referred to as absorbent core) by a non-breathable material, but having other parts of the article made of breathable materials.

In general, the prior art helped to improve the breathability of the roofing materials, or helped to keep only parts of the article fully respirable. However, the prior art failed to recognize that the particular benefits can be obtained by selectively combining the materials in certain regions of the article, and in particular by exploiting the benefits of the absorbency properties of the absorbent core of the article. The absorbent core of an absorbent article needs to be able to acquire, distribute and store the discharges that are initially deposited on the topsheet of the absorbent article. Preferably, the design of the absorbent core is such that the core acquires the discharges substantially immediately after they have been deposited on the top sheet of the absorbent article, with the intention that the discharges do not accumulate on or leave the top sheet, since this can result in inefficient containment of the fluid by the absorbent article, which can lead to wetting of external garments and discomfort for the wearer. After the delivery, the functionality of the absorbent article is essential to retain the discharged fluids firmly to avoid excessive hydration of the user's skin. If the absorbent article does not work well in this respect, the liquid coming from the absorbent core returns to the skin, also often called "rewetting", can have detrimental effects on the condition of the skin, which can result in excessive hydration. and consequently a superior propensity to skin irritations. There have been many attempts to improve the fluid handling properties of absorbent articles or cores, in particular when additional requirements were discussed such as a desired reduction in volume or thickness of the product. These effects were discussed in European Patent Application 96105023.4 filed on March 29, 1996, but also in U.S. Patent No. 4,898,642; in European Patent EP-A-0 640 330; in European Patent EP-A-0 397 110; and in European Patent EP-A-0 312 118. All attempts helped to improve the interaction of the surface of the skin-oriented article with the wearer's skin. It has not been sufficiently recognized, that there is an interaction between the good functioning of rewetting the article and a high ventilation through the materials of the back sheet. It has not been sufficiently recognized that the combination of cores that have a very good liquid handling performance, which results in very good skin dryness, and the back sheet materials that allow very good breathability, can have a synergistic effect. It has not been sufficiently effected, that these well-functioning cores allow much greater design flexibility for the article and the properties of the backsheet materials that cover the core with respect to liquid permeability, thus allowing air permeability or even more superior steam. Accordingly, it is an object of the present invention to provide disposable absorbent articles that provide particularly good rewet performance of the core with the vapor permeable backsheet materials, which have increased vapor permeability of the backsheet materials of the chassis that surround the nucleus. It is a further object of the present invention to provide highly permeable materials to the vapor in the region of the core and the chassis. Therefore, materials that allow the dominance of driving transport mechanisms can still be used. It is a further object of the present invention to use these materials as backsheet materials in combination with an absorbent core having a high liquid absorbency capacity.

BRIEF DESCRIPTION OF THE INVENTION A disposable absorbent article that aids improved ventilation of the skin by combining the benefits of an absorbent core that provides good rewet performance and the use of backsheet materials, which, where they cover the core area, provide superior vapor permeability , and which have even higher permeability in the region or regions of the chassis that surround the core region.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is schematically showing a baby diaper with ribbons as an example of absorbent article. Figure 2 is schematically showing a diaper that notches the baby as an example of an absorbent article. Figure 3 is showing the test carried out for the Proof of Acquisition. Figure 4 is showing the test carried out by the Re-wetting Method of Post-Acquisition Collagen.

DETAILED DESCRIPTION Absorbent Articles - General.

As used herein, the term "absorbent articles" refers to devices that absorb and contain exudates from the body, and more specifically, refers to devices that are positioned against or in proximity to the user's body to contain and absorb the variety of Exudates discharged from the body, mainly urine. The term "disposable" herein is used to describe absorbent articles that are not intended to be laundered or otherwise restored or rejected as an absorbent article (for example, they are proposed to be disposed of after use and, preferably, to be recycled, formed in compost or otherwise disposed of in some way compatible with the environment). Within the context of the present invention, the absorbent article comprises: a) an absorbent core (which may consist of substructures and / or wrapping materials), which includes on the user-facing side an upper sheet, which forms the surface internal and which, at least in certain regions of the same, allows the exudates to penetrate through it, and that includes on the opposite side a back sheet that forms the external surface of the article and which separates the core from the outside , such as the wearer's clothes. b) elements of the chassis that include features such as closing or elasticizing elements to maintain the article in the user. Also comprising a top sheet that forms the inner surface of a back sheet. The backsheet and top materials of the absorbent core can be untied with respect to the materials in the chassis regions, i.e. the backsheet can cover the absorbent core and the same material or sheet can extend into the region of chassis, in this way, for example, covering the characteristics such as leg elastics or similar.

Figure 1 is a plan view of an embodiment of an absorbent article, which is a diaper. The diaper 20 is shown in Figure 1 in its non-contracted, flat state (for example with elastic-induced contraction pulled out except for the side panels where the elastic remains in its relaxed condition) with portions of the structure being cut to show more clearly the construction of the diaper 20 and with the portion of the diaper 20 facing from the wearer, the outer surface 52, facing the viewer. As shown in Figure 1, the diaper 20 comprises a liquid-permeable upper sheet 24, a liquid-impermeable back sheet 26 attached to the upper sheet 24, and an absorbent core 28 positioned between the upper sheet 24 and the back sheet 26; elasticized side panels 30; folds of elasticized legs 32; a characteristic of elastic waist 34; and a closure system comprising a double tension clamping system generally designated multiple 36. The double clamping system by tension 36 preferably comprises a primary fastening system 38 and a waist closure system 40. The primary fastening system 38 preferably comprises a pair of security members 42 and a landing member 44. The waist closure system 40 is shown in FIG. 1 to preferably comprise a pair of first fastening components 46 and a second fastening component 48. The diaper 20 preferably also comprises a locating patch 50 underlying each first fastening component 46. The diaper 20 is shown in FIG. the figure having an external surface 52 (facing the observer in figure 1), an inner surface 54 opposite the outer surface 52, a first waist region 56, a second waist region 58 opposite the first waist region 56, and a periphery 60 that is defined by the outer edges of the diaper 20 on the sides which longitudinal edges 62 are designated and end edges 64 are designated. The inner surface 54 of the diaper 20 comprises such a portion of the diaper 20 that is positioned adjacent to the wearer's body during use (e.g. the inner surface 54 is generally formed by at least a portion of the topsheet 24 and other components attached to the topsheet 24). The outer surface 52 comprises such a portion of the diaper 20 that is positioned away from the wearer's body (for example, the outer surface 52 is generally formed by at least a portion of the backsheet 26 and other components attached to the backsheet 26). The first waist region 56 and the second waist region 58 extend, respectively, from the end edges 64 of the periphery 60 to the center line 66 of the diaper 20. Each of the waist regions comprises a central region 68 and a waist region. pair of side panels typically comprising the outer side portions of the waist regions. The side panels placed in the first waist region 56 are designated 70 while the side panels in the second waist region 58 are designated 72. While it is not necessary for the pairs of side panels or each side panel to be identical, they are preferably mirror images of each other. The side panels 72 placed in the second waist region 58 can be elastically extensible in the lateral direction (eg elasticized side panels 30). (The lateral direction (x or width direction) is defined as the direction parallel to the lateral centerline 66 of the diaper 20; the longitudinal direction (direction y or length) being defined as the direction parallel to the longitudinal center line 67; and the axial direction (z direction or thickness) being defined as the direction extending through the thickness of the diaper 20). Figure 1 shows a specific embodiment of the diaper 20 in which the topsheet 24 and the backsheet 26 are unitary through the core and the region of the chassis and have length and width dimensions generally greater than those of the absorbent core 28. The topsheet 24 and the backsheet extend beyond the edges of the absorbent core 28 to thereby form the periphery 60 of the diaper 20. The periphery 60 defines the outer perimeter or, in other words, the edges of the diaper 20. The periphery 60 comprises the longitudinal edges 62 and the end edges 64. Although each elasticized fold of the leg 32 may be configured to be similar to any of the leg bands, side flaps, barrier folds, or elastic folds described above. , it is preferable that each fold of the elasticized leg 32 comprises at least one internal barrier fold 84 comprising a barrier flap 85 and an elastic limb of the barrier. separation 86 as described in the aforementioned United States Patent No. 4,909,803. In a preferred embodiment, the elasticized leg bending 32 further comprises a resilient girdle fold 104 with one or more elastic filaments 105, placed outside of the barrier fold 84 described in the aforementioned US Patent No. 4,695,278. The diaper 20 may additionally comprise an elastic waist feature 34 that provides improved fit and containment. The elastic waist feature 34 at least extends longitudinally outwardly from at least one of the waist edges 83 of the absorbent core 28 in at least the central region 68 and generally forms at least a portion of the end edge 64 of the diaper 20. Thus, the elastic waist feature 34 comprises that portion of the diaper that at least extends from the waist edge 83 of the absorbent core 28 to the end edge 64 of the diaper 20 which is intended to be placed adjacent to the waist. of the user. Disposable diapers are generally constructed to have two elastic waist features, one placed in the first waist region and the other placed in the second waist region. The elasticized waistband 35 of the elastic waist feature 34 may comprise a portion of the upper sheet 24, a portion of the back sheet 26 that has been preferably mechanically stretched and a two-sheet material comprising an elastomeric member 76 positioned between the top sheet 24 and the back sheet 26 and the elastic member 77 positioned between the back sheet 26 and the elastomeric member 76. This as well as other components of the diaper are given in more detail in the international publication WO 93/16669 which is incorporated here for reference. Figure 2 shows a further example of an absorbent article for which the present invention can be applied, ie a disposable diaper that is lifted. The disposable diaper 20 comprises an absorbent core 22, a chassis 21 surrounding the region of the core and side seams 10. The outer layers or backsheet 26 are those portions of the chassis 21 or the absorbent core 22 that will form the exterior of the Disposable diapers that rises 20, that is, they give away from the user. The outer layers 26 are docile, soft feeling and non-irritating to the wearer's skin. This outer layer may be a layer of unitary material covering both the core and the regions of the chassis or parts thereof, or it may comprise different materials in these regions. The inner layers or upper sheet 24 are those portions of the chassis 21 or core 22 that will form the interior of the article, and will be in contact with the user. The inner layer is also docile, soft feeling and non-irritating to the user's skin. In the chassis region, the inner layer 24 and the outer layer 26 can be indirectly joined together by attaching them directly to the elastic ear flap members 90, elastic waist band members 76, and elastic filaments 105, and can be directly joined each other in the areas extending beyond the elastic ear flap member 90, elastic waistband members 76 and elastic filaments. The chassis 21 of the disposable diapers 20 preferably preferably further comprise folds of elasticized legs 32 to provide improved containment of liquids and other exudates from the body. Each elasticized leg fold 32 may comprise several different embodiments to reduce runoff of the body exudates in the leg regions. Although each fold of the elasticized leg 32 may be configured in such a way to be similar to any of the leg bands, side flaps, barrier folds, or elastic folds described above, it is preferred that each elastic leg fold 32 comprises less a side flap 104 and one or more elastic filaments 105. The chassis 21 of the disposable diapers 20 further preferably comprises an elasticized waistband 34 positioned adjacent the end edge of the disposable diapers that rise at least at rear portion 58, and more preferably has an elasticised waistband 34 positioned on both, the front portion 56 and the rear front portion 58.

Absorbent Core / Core Structure The absorbent core must be generally capable of compressing, comfortable, non-irritating to the wearer's skin, and capable of absorbing and retaining liquids such as urine and certain other exudates from the body. The absorbent core may comprise a wide variety of liquid handling or liquid absorbent materials commonly used in disposable diapers and other absorbent articles such as, but not limited to, crushed wood pulp which is generally referred to as an air filter.; meltblown extrusion polymers including coform; chemically hardened, modified or crosslinked cellulosic fibers; tissue that includes tissue wrapping or tissue laminates. Examples of absorbent structures are described in U.S. Patent No. 4,610,678 entitled "High Density Absorbent Structures" issued to Weisman et al. On September 9, 1986, U.S. Patent No. 4,673,402 entitled "Absorbent Articles With Double-Layer Cores "issued to Weisman et al. On June 16, 1987, U.S. Patent No. 4,888,231 entitled" Absorbent Core Having a Dust Cap "issued to Angstadt on December 19, 1989; European Patent EP-A-0 640 330 to Bewick-Sonntag et al .; U.S. Patent No. 5,180,622 (Berg et al.); U.S. Patent No. 5,102,597 (Roe et al.); U.S. Patent No. 5,387,207 (LaVon). Such structures can be adopted to be compatible with the requirements outlined below to be used as the absorbent core 28. The absorbent core 28 can be a unitary core structure, or it can be a combination of several absorbent structures, which in turn can consist of of one or more substructures. Each of the structures or substructures can have an essentially two-dimensional extension (ie, be of one layer) or a three-dimensional shape.

Materials for Use in Absorbent Nuclei of the Invention The absorbent core for the present invention may comprise fibrous materials to form fibrous webs or fibrous matrices. Fibers useful in the present invention include those that are naturally occurring fibers (modified or unmodified), as well as synthetically made fibers, such as polyolefins such as polyethylene and polypropylene. For many absorbent cores or core structures according to the present invention, the use of hydrophilic fibers which can be obtained using hydrophilic starting materials or hydrophilizing the hydrophobic fibers, such as thermoplastic fibers treated with surfactants or treated with silica, is preferred. derived from, for example, polyolefins. The fibers of suitable occurrence are the fibers of wood pulp can be obtained from well-known chemical processes such as the Kraft and sulfite processes. Also chemically hardened fibers are suitable, where for example, crosslinking agents can be applied to the fibers which, after application, thus causing the chemically formed cross-fiber bonds which can increase the stiffness of the fibers. . Although the use of interfiber network links is preferred, this does not mean excluding other types of reactions for the chemical hardening of the fibers. Fibers hardened by individually crosslinked bonds (for example, hardened individualized fibers, as well as the process for their preparation) are disclosed, for example, in U.S. Patent No. 3,224,926; U.S. Patent No. 3,440,135; U.S. Patent No. 3,932,209; and in U.S. Patent No. 4,035,147; U.S. Patent No. 4,898,642d; and in U.S. Patent No. 5,137,537 (Herron et al.), issued August 11, 1992. In addition to or alternatively the thermoplastic or synthetic fibers may be comprised in the absorbent structures, being made of any thermoplastic polymer that can be melted at temperatures that extensively damage the fibers. The thermoplastic materials may be made from a variety of thermoplastic polymers, including polyolefins such as polyethylene. The surface of the hydrophobic thermoplastic fiber can be converted into hydrophilic by treatment with a surfactant, such as a nonionic or anionic surfactant, for example, by spraying the fiber with a surfactant, bathing the fiber within a surfactant or including the surfactant as part of the molten polymer in the production of the thermoplastic fiber. Upon melting and re-solidifying, the surfactant will tend to remain on the surface of the thermoplastic fiber. Surfactants may also be used which include nonionic surfactants such as Brij® 76 manufactured by ICI Americas, Inc., of Wilmington, Delawer, and various surfactants sold under the tradename Pegosperse® by Glyco Chemical Inc. of Greenwich, Connecticut. . In addition to the nonionic surfactants, anionic surfactants can also be used. These surfactants can be applied to the thermoplastic fibers at the levels of, for example, from about 0.2 to about 1 gram square centimeter of thermoplastic fiber. Convenient thermoplastic fibers may be made of a simple polymer, (one-component fibers), or may be made of more than one polymer (e.g. two-component fibers.) For example, "two-component fibers" may refer to the thermoplastic fibers comprising a core fiber made of a polymer that is encased within a thermoplastic shell made of a different polymer.The polymer comprising the shell often melts at a different temperature, typically lower, than the polymer that As a result, these two-component fibers provide thermal bonding due to fusion of the shell polymer, while retaining the desirable strength characteristics of the core polymer.In the case of thermoplastic fibers, their length may vary depending on the particular melting point and other properties desired for these fibers, typically, these thermo fibers plastics 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. The properties, including the melting point, of these thermoplastic fibers can also be adjusted by varying the diameter (gauge) of the fibers. The diameter of these thermoplastic fibers is typically defined in terms of either denier (grams per 900 meters) or decitex (grams per 10,000 meters decitex.) Depending on the specific arrangement within the structure, suitable thermoplastic fibers may have a decitex in the interval, from well, below 1 decitex, such as 0.4 decitex to approximately 20 decitex. Said fibrous materials can be used in an individualized way when the absorbent articles are being produced, and a fibrous structure placed by air is formed on the line. Said fibers can also be used as a fibrous web or preformed tissue. These structures are then supplied to the production of the article essentially in a continuous or very long form (for example, in a roll, reel) and then it will be cut into the appropriate size. This can be done in each of such materials individually before they are combined with other materials to form the absorbent core, or when the core itself is cut and said materials are coextensive with the core. There is a wide variety of making such wefts or tissues, and such processes are well known in the art. In addition to or alternatively to the fibrous webs, the absorbent cores may comprise other waste materials, such as foams. Preferred foams are open cell absorbent polymeric foam materials as derived by polymerizing a High Internal Phase Water Emulsion (hereinafter referred to as EAFI). Such polymeric foams can be formed to provide the required storage properties, as well as the distribution properties that are required, as described in copending United States Patent Application Serial Number 08 / 563,866 (DesMarais et al.) , presented on November 25, 1995; U.S. Patent Application Serial Number 08 / 542,497, filed October 13, 1995 (Dyer et al.); U.S. Patent No. 5,387,207 (Dyer et al.) issued February 7, 1995; and U.S. Patent No. 5,260,345 (DesMarais et al.) issued November 9, 1993.

Superabsorbent polymers or hydrogels Optionally, and often preferably, the absorbent structures according to the present invention may comprise superabsorbent polymers or hydrogels. The hydrogel-forming absorbent polymers useful in the present invention include a variety of polymers substantially water insoluble but capable of swelling in water, capable of absorbing large quantities of liquids. Such polymeric materials are also commonly referred to as "hydrocolloid" or "superabsorbent" materials. These hydrogel-forming absorbent polymers preferably have a multiplicity of anionic, functional groups, such as sulfonic acid, and more typically carboxy groups. Examples of suitable polymers for use herein include those which are prepared from acid-free, unsaturated, polymerizable monomers. The hydrogel-forming absorbent polymers suitable for the present invention contain carboxy groups. These polymers include acrylonitrile-hydrolyzed starch graft copolymers, partially neutralized acrylonitrile-starch graft copolymers, acrylic acid-starch graft copolymers, partially neutralized acrylic acid-starch graft copolymers, acrylic ester-vinyl acetate copolymers saponified, hydrolyzed acrylamide or acrylonitrile copolymers, polymers lightly crosslinked in the network of any of the above copolymers, partially neutralized polyacrylic acid, and slightly crosslinked copolymers in the partially neutralized polyacrylic acid network. These polymers can be used either alone or in the form of a mixture of two or more different polymers. Examples of these polymeric 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 hydrogel-forming particles are lightly networked polymers of partially neutralized polyacrylic acids and starches derived from the foregoing. More preferably, the hydrogel forming particles comprise from about 50 to about 95%, preferably about 75%, of polyacrylic acid, lightly cross-linked in the network, neutralized (ie, polyacrylic acid-sodium acrylate). As described above, the hydrogel-forming absorbent polymers are preferably slightly cross-linked in the network. Cross-linking in the network serves to convert the substantially insoluble polymer into water and, in part, determines the absorbent capacity and the characteristics of the extractable polymer content of the precursor particles and the resulting macrostructures. The processes for network crosslinking, polymers and typical network crosslinking agents are described in greater detail in the above-referenced U.S. Patent No. 4,076,663, and in German Patent DE-A-4020780 (Dahmen). The superabsorbent materials can be used in particulate or fibrous form and other elements can also be combined to form preformed structures. Although the individual elements have been disclosed separately, an absorbent structure or substructure can be made by combining one or more of those elements.

Design Capacity and Final Storage Capacity In order to be able to compare absorbent articles by varying end-use conditions, or items with different sizes, the "design capacity" has been found to be a convenient measure. For example, babies who are representing a typical user group, but still within this group the amount of urine load, load frequency, composition of the urine will vary widely from the smallest babies (newborn babies) to children who start to walk, on the one hand, or also for example among several individual children who begin to walk. Another group of users may be older children, who still suffer from some form of incontinence. Also, incontinent adults can use such items, again with a wide range of load conditions, generally referred to as light incontinence ranging up to severe incontinence. Although the person skilled in the art will easily be able to transfer the teachings to other sizes for later discussions, attention will be placed on babies the size of children who are just beginning to walk. For such users urine loads of up to 75 ml per evacuation, with an average of four evacuations per period of use resulting in a load of 300 ml., And evacuation rates of 15 ml have been found to be sufficiently representative. sec. Therefore, such articles being able to encompass such requirements must have the ability to collect such amounts of urine, which will be referred to for later discussions as "design capability". These quantities of fluids have to be absorbed by materials that can finally store the bodily fluids, or at least the aqueous parts of them, in such a way that, if there is, only little fluid is left on the surface of the article towards the skin of the body. user. The term "final" refers in one respect to the situation of the absorbent article in long periods of use, in the other respect to absorbent materials that reach their "final" capacity when they are balanced with their environment. This may be in such an absorbent article under actual conditions of use after long periods of use, or this may also be in a test procedure for pure materials or composite materials. Since many of the processes under consideration have an asymptotic kinetic behavior, one skilled in the art will readily consider that the "final" capacities are reached when the actual capacity has reached a value sufficiently close to the asymptotic endpoint, for example, relative to the accuracy of equipment measurement. As an absorbent article may comprise materials that are mainly designed to store fluids lately, and other materials that are mainly designed to satisfy other functions such as fluid acquisition and / or distribution, but may still have some final storage capacity, the materials Suitable core materials according to the present invention are described without intending to artificially separate such functions. However, the final storage capacity can be determined by the total absorbent core, for the regions thereof, for the absorbent structures, or even the substructures, but also for materials as used in any of the foregoing. In the case of applying the present invention to other articles that. require different end uses, one skilled in the art will be able to easily adopt the design capabilities appropriate for the other user groups. In order to determine or evaluate the final design storage capacity of an absorbent article, a number of methods have been proposed.

Within the context of the present invention, it is assumed, that the final storage capacity of an article is the sum of the final absorbing capacities of the individual elements or materials. For these individual components, several well-established techniques can be applied as long as they are applied consistently throughout the comparison. For example, the centrifugal capacity of the Tea bag as developed and well established for super absorbent polymers can be used for those materials, but also for others (see above). Once the capacities for the individual materials are known, the total absorbent capacity can be calculated by multiplying these values (in me per gram) with the weight of the material used in the article. For materials that have a dedicated functionality different from the final storage of the fluid, such as the acquisition layers and the like, the final storage capacity can be neglected, either as those materials, in fact they have only very low capacity values compared to the dedicated final fluid storage materials, or as these materials are intended not to be loaded with fluid, and in this way must release their fluid towards other final storage materials. With these definitions, the so-called "pantiprotectors" exhibit very low final storage capacities of a few mi. or less. Catamenial pads often have up to about 20 ml., Articles for light urinary incontinence have, for example, 75 ml. or approximately 90 mi., the articles for medium urinary incontinence, or also the diapers of small babies can have approximately 165 mi., and the diapers of babies that begin to walk reach 300 mi. or more, and articles for severe adult incontinence having 600 mi. or more than the final storage capacity.

Breathable Back Blade Materials An essential element of the present invention is the use of materials that are permeable to gas, such as air, or to vapor, such as water vapor. Apart from diffusion, gases or vapors can pass through a solid material through small (slow) capillary transport, or conduction transport (fast). The permeability can be determined by the well known humeral vapor transmission regime (MVTYR), expressed in units of (g / 24h / m2) under various driving transport forces. For the context of the present invention, the method as disclosed below is related to the calcium-chloride absorption moisture through the test specimen under a relative humidity of 75% at 40 ° O- One more way to determine the permeability Gas is applying an air permeability test, with which air is sucked through the test specimen under defined conditions such as vacuum suction. As this test is related to high penetration rates, it is more applicable to the materials that allow the conduction air flow (fast) instead of capillary transport or diffusion dominated (slow). Examples of these materials are so-called microporous films, for example as they can be provided by Mitsui Toatsu Co., Japan, under the designation ESPOIR NO. These films can be made by producing a polymer film such as polyethylene, further comprising filler particles, such as calcium carbonate. After having formed a film where these filler particles are embedded in a matrix of polymeric material, the film can be mechanically treated to permanently tension and stretch the polymeric materials, thereby creating small cracks around the non-deforming filler particles. The cracks are small enough to allow the molecules of the gas phase to pass through., but prevent liquids from penetrating. In this way, transport mechanisms are slow flowing in the capillaries. The deformation can be achieved by a number of different ways, in the machine direction of the material such as by conventional stretching between two gripping roller arrangements running at a differential speed, or in directions transverse to the machine such as by setting under tension the edges of the material in divergent frames, or making it run through narrower internal gear rollers, or by any combination thereof. Each of these steps can be executed while the material is heated (ie, at a temperature that exceeds the ambient temperature, that is, very frequently at a temperature above about 40 ° C) or "cooled down", ie, below that temperature. The microporosity of these materials can be imparted as an integral stage of the process of the film formation process, this can be a separate stage of the process, or this can be a stage of the process that is integrated in an additional conversion of these materials, such as when these films are used to produce the absorbent articles. When using plastic film materials, it has been found that often, that plastic sensation is not preferred by consumers. Therefore, it is often desired to have an improved hand of these materials, which can be achieved, among other ways, by combining a layer of fibrous material to the film, such as a low basis weight nonwoven material. These layers can be fixed to the film by various methods, such as using adhesives or thermally fixing these together. Within the context of the present description, the films manufactured or treated as described above can be classified as follows: Table 1 MVTR permeability range (g / m2 / 24h) Not permeable up to 200 approximately Low permeability up to 2000 approximately Average permeability up to 4000 approximately High permeability up to 6000 approximately Very high permeability more than 6000 These values should be compared to a value of approximately 12,000 g / m2 / 24h, which would be required to protect human skin without providing significant additional resistance to the transfer of moisture away from the skin, or alternatively result when operates the MVTR test without a test material. Alternatively, these materials can be made from non-woven materials, which have been made liquid impervious such as by, or, reduce the pore size of the woven material, for example, by combining spunbonded webs with blown webs. in the molten state (SMS) or through other treatments. Furthermore, the materials can be perforated films, whereby these materials can exhibit liquid impermeability in a direction as described in European patent EP-A-0.710.471. These materials often have high or very high permeability values, such as about 4500 g / m2 / 24h at 6000 g / m2 / 24h for the nonwoven webs, so that these can also be described in a significant way by the values of air permeability (see below), with which from approximately 1500 to 2500 l / cm2 / sec result for conventional SMS materials from 2000 to 2300 l / cm2 / sec for common carded frames and more than 2500 l / cm2 / sec for spun glued weights of low base weight.

Article Regions However, apart from the selection of the appropriate materials, the disposition of the materials within the article are of high importance. For the scope of the following description, the article is being considered to consist essentially of two regions, mainly a part of the article comprising the absorbent core, the other part complementing the rest of the article. In this way the "core region" covers the regions that will cover in use the body opening from which the exudates are discharged and will extend further to the waist region or waist regions. In addition to the liquid handling means and the auxiliary means such as the elements for holding together several other elements, (for example, adhesives), this region of the core will comprise one or more materials that are intended to face towards the user's skin during the use, and which are generally referred to as the materials of the top sheet, and one or more materials that are intended to cover the opposite surface of the article (ie, the exterior), in this way for example helping to be oriented toward the user's clothes The "chassis region" comprises the designed elements of the article to hold the article in the user (i.e., the fastening means), the elements that prevent the exudates from leaking out of the article (for example, the elastification means of leg closure, or waist features), and the means to connect the various elements.

Also the chassis region will comprise one or more materials that are intended to face the user's skin during use, and which are generally referred to as the top sheet, and one or more materials that are intended to cover the opposite surface of the article. (ie, the outer side), in this way for example, facing to be oriented towards the user's garments, which are generally referred to as the materials of the back sheet. With respect to the fluid penetration properties, ie the gas permeability and the liquid impermeability, there are different requirements for the materials of the backsheet in the region of the chassis and the core of the article. In the chassis area, the material of the backsheet should avoid obstruction of the skin and therefore allow the sweat to evaporate through it very easily, that is, a high gas permeability, but the material does not need to meet the specific requirements of the impermeability to the liquid. In the core area, there is an additional requirement for the backsheet material to retain the free liquid, such as before it is absorbed, or when the absorbent structure reaches saturation. In this way, in conventional designs that use conventional materials, they have to satisfy the requirements of high liquid impermeability, mainly to prevent the liquid from penetrating through these materials. Therefore, the conventional backsheet materials of the core region are essentially liquid impervious, as can be determined by the hydrostatic head test, resisting there a water height of at least 140 ml. When a breathable material is used in these articles, and especially in articles with relatively high liquid holding capacities, essentially there are two conventional designs: any that use materials essentially impervious to vapor in the core region (regardless of whether in combination with others materials that could be vapor permeable), or using microporous materials at no more than a moderate level in all of both of the core region and the chassis.

Core Operation v Breathability However, the recent development of the absorbent cores that have a high liquid retention capacity allows a different approach, reducing the liquid impermeability requirement for the backsheet material of the core region. These well-functioning items can be described as having low rewet performance. The post-acquisition collagen rewet method (PACORM) has been found to describe this performance well, thus for values of nuclei with low performance of 150 mg. in higher results, for nuclei with average performance of between approximately 110 mg. and 140 mg., for nuclei with good performance of between 110 mg. and approximately 80 mg., and for nuclei with very good performance less than 80 mg. Still smaller values such as 72 mg. or less are even more preferable. These core designs with good or better performance, as described in greater detail in European patent application 96105023.4, allow an improved selection of the materials, mainly allowing higher breathability values in the backsheet material within the region of the core. According to the present invention, this selection can be taken better considering the parameters that combine the two effects, namely the ratio of the PACORM values of the absorbent core to the MVTR values of the backsheet material covering the core. , which can be derived when this is considered as a first approximation of the order of the operation of the breathability and both the operation near the nucleus and the breathability of the materials of the posterior sheet in the core region. Although this approximation is linearized, this relationship results in units of mg / [g / m2 / 24h]. In this way, it remains relevant that the respirability of the region or chassis regions be maximized, and thus superior to that of the core region, such as having an MVTR value of 1.2 times the value for the core. Preferably, the chassis region must have an MVTR value of at least about 4500 g / m2 / 24h. If the chassis or core region comprises subregions with variable MVTR values, these can be averaged over the weighted average of the area. The relationship of PACORM values and MVTR values should be minimized, so that they can be achieved by small PACORM values and / or high PACORM values. It has been found that the ratios of 0.028 (mg / [g / m2 / 24h)] work well and that a ratio of less than 0.019 (mg / [g / m2 / 24h]) or even less than 0.012 (mg / [g / m2 / 24h]) is even more preferable.

Examples In order to further exemplify the benefits of the current invention, samples of different baby diapers have been supplied in test protocols as outlined herein. For reasons of comparability, they were all of comparable size, especially for babies of approximately 9 to 18 kg., Often called MAXI (or size MAXI PLUS) or "SIZE 4".

The base for several samples is commercially available product, size PAMPERS Baby Dry Plus Maxi / MAXI PLUS as marketed by Procter & Gamble in Europe, where the core has been modified by the following steps: First, the chemically treated, hardened (CS) cellulose material, supplied by Weyerhaeuser, Co., USA, under the commercial designation "CMC" that functions as a acquisition / distribution layer has a basis weight of approximately 500 gr. per square meter. Second, an additional acquisition layer was introduced between the top sheet and said chemically treated cured cellulose layer, especially a chemically bonded non-woven high-floor material as supplied by FIBERTECH, North America under the designation type 6852. This is a chemically bonded PET fiber weft with a basis weight of 42 gr. per square meter and a width of 110 mm. about the total length of the absorbent core. Third, the cellulose material used in the absorbent core below the chemically treated hardened cellulosic material is reduced to approximately 11.5 g. per pad. Fourth, the amount of superabsorbent material within this storage core is increased to approximately 16 gr. per pad. The superabsorbent material was supplied by Stockhausen GmbH, Germany, under the trade name FAVOR SXM, type T5318. These cores have been used to make the following samples: For example 1, the conventional PE backsheet has been replaced by a non-woven material, essentially a 27 g / m2 PP, hydrophobic web, as supplied by SANDLER Schwarzenbach, FRG, under the designation VP 39522. In the center of the article a film of microporous films as supplied by MITSUI Toatsu Co., Japan, under the designation ESPOIR NO. It has been laminated with glue with the application of spiral glue. More example 2 can be made by replacing the central cover strip of the core of Example 1 with the film as supplied by EXXON Chemicals, III, USA, under the designation EXXAIRE. Also, example 2 is based on the same modified core. This product, however, is a so-called "standing up" diaper, whereby the side seams are merged together to create an article similar to a brief. The backsheet covering the entire article is made of a nonwoven material of the type as in example 1, and the core region additionally comprises a strip of microporous film placed between the backsheet and the core of the same type as in the example 1. These products have been submitted to the PACORM Test, and the respective materials to the MVTR test, with the following results: TABLE 2 PACORM MVTR Relationship (mg) (g / m2 / 24h) (mg / [g / m2 / 24h]) Core Chassis Example 1 72 3800 4500 0.019 Example 2 72 4500 4500 0.016 Example 3 72 3800 4500 0.019 As comparative examples, the following products have been evaluated: Comparative example 1 is based on a commercially available product, especially PAMPERS PREMIUM, SIZE 4, as sold by Protecter & Gamble in the USA, with a modified core design as examples 1 and 2, where the PE backsheet has been perforated in the ear section of the diaper with apertures of approximately 0.5 mm in diameter to approximately 140 openings / cm2 resulting in an open area of approximately 27%. Comparative example 2 is a commercially available product as sold by UniCharm Corp., in Japan, under the trade designation Moonyman, size 4. This product has a microporous film with medium permeability covering both the core and chassis regions. The comparative example 3 is a diaper that rises as in example 3, however it does not contain the modified core of example 3, but the conventional core of PAMPERS BABYDRY PLUS. Comparative Example 4 is a commercially available product such as one marketed by Kimberly-Clark under the trade name of HUGGIES Flexifit with mechanical fasteners, size 4 in the United Kingdom. As for the materials of the backsheet, the product has a nonwoven material on the outside, and the core region covered by a microporous film of low permeability.

TABLE 3 PACORM MVTR Relationship (mg) (g / m2 / 24h) (mg / [g / m2 / 24h]) Core Chassis Example 72 200 1500 0.36 Comparative 1 Example 180 3300 3300 0.042 Comparative 2 Example 110 3800 6000 0.029 Comparative 3 Example 140 2000 6000 0.07 Comparative 4 PROOF PROCEDURE Humid Steam Transmission Regime The rate of wet steam transmission is the measurement of the amount of moisture absorbed by calcium chloride in a "cup" -like container covered with a test specimen from controlled external air conditions (40 + 3 ° C / 75 + 3% relative humidity). The sample holding a cup is a cylinder with an internal diameter of 30 mm. and an interior height from the bottom to the top flange of 49 mm. A flange having a circular opening to equalize the opening of the cylinder can be fixed by screws, and a sealing ring of silicone rubber, equal to the internal diameter, is fitted between the upper flange and the cylinder. The specimen sample is to be placed in such a way as to cover the opening of the cylinder, and can be tightly fixed between the silicone rubber seal and the upper rim of the cylinder. This equipment as well as the specimen sample must be well adjusted to the temperatures, and the constant temperature / humidity chamber preferably has a size to accommodate up to 30 samples. The absorbent desiccant material is CaC12, such as can be sold from Wako Puré Chemical Industries Ltd., Richmond, VA, USA, under the product designation 030-00525. If it is kept inside a closed bottle, it can be used directly. This can also be sieved to remove lumps, and excessive amounts of fines, if any. This can also be dried at 200 ° O for about 4 hours. Weigh 15.0 + 0.02 g of CaC12 into the cup, and decant slightly to level it, so that the surface is approximately one centimeter from the top of the cup. The samples, which are cut to approximately 3.2 cm. by 6.25, cm. they are placed flat and overlapping with the seal on the opening, and the seal and the upper flange are fixed by the screws without excessive adjustment. The total weight of the cup assembly is recorded exactly at a scale of 4 tenths of a place, and the assembly is placed inside the chamber at constant temperature / humidity. After 5 hours (without opening the chamber), the sample is removed and immediately covered in an airtight manner with a non-vapor permeable plastic film such as the Saran wrap as commonly used in the United States. After about 30 minutes to allow temperature equilibrium, the plastic film cover is removed and the exact weight of the assembly is recorded.

The value of MVTR is then calculated from the increase in humidity during these 5 hours through the circular opening of 3 cm. and then converted to units of "g / 24h / m2". For each test, three replicates must be run, the resulting values will be averaged, and the result rounded to the value closest to 100. In general, this method is applicable to thin films, laminates of multiple layers and the like. Experience has shown, that typical standard deviations vary between 50 and 200 g / 24hr / m2 for averaged values of up to approximately 5000 g / 24hr7m2. Due to this range, materials that are considered to be essentially value impervious such as conventional PE films are reported to have an MVTR of approximately 200 g / 24hr / m2. If units for an MVTR value are omitted for simplicity, a material "having an MVTR value of 1000" must be exactly a material "having an MVTR value of 1000 g / 24 / m2" according to this method .

Air Permeability The air permeability is determined by measuring the time at which a standard air volume is aspirated through the test specimen at a constant temperature and pressure. This test is particularly suitable for materials having relatively high gas permeability, such as nonwovens, films with openings and the like. The test is operated in a controlled environment of temperature and humidity at 22 + 2 ° C and 50 + 2% relative humidity. The test specimen must be conditioned for at least two hours.

The test equipment as manufactured by Hoppe & Schneider GmbH, Heidelberg, Germany, under the designation "Textiluhr nach Kretschmar", is essentially a bellows in a vertical arrangement, with its upper end which is mounted in a fixed position, and the lower end which is releasably held in its position upper, which can be loosened by means of a release handle to slide under controlled conditions to the lower position, thus increasing the volume within the bellows by pushing air through the test specimen which is covering the air inlet opening at the upper end of the bellows. The test specimen is held firmly to cover the air inlet opening by means of a 5 cm clamping ring. square or 10 cm. squares to make room for different sample sizes and / or different permeability ranges. If the 10 cm.quared ring is used, the sample must be at least 55 mm. of width, for the ring of 5 cm. squared at least 35 mm. For both the samples should have a length of approximately 150 mm. Optionally, the sample retention device may comprise a stretching element, in such a manner as to allow measurements of the elastic materials under stretched conditions. The equipment includes a stopwatch (1/100 sec) which automatically measures the time between the operation of the release handle, thus starting the sliding of the bellows, and the lower part of the bellows that reaches its lower final position. The air permeability of the material can then be calculated by dividing a constant as provided by the supplier for each equipment (for the present equipment K = 200,000 for a tested area of 5 cm.2, and 400,000 for an area of 10 cm2. ) for time as measured in seconds, resulting in units of [l / cm2 / sec].

The test is repeated once for each test specimen, and must be repeated on 10 specimens to provide a representative basis for a material.

Impermeability to the Liguid (Hydrostatic Height Test) The principle of the test is to increase a height of distilled water on the upper side of the test specimen of approximately 64 cm. squares, such as a film or other porous material. The test specimen is cut to approximately 10 cm. by 10 cm., and it is placed on a sample plate, also of a size of 10 cm. by 10 cm. with a centered O-ring seal of approximately 8 cm. diameter. The sample plate has a centered opening of approximately 7.6 cm. diameter to allow observation of the underside of the test specimen during the test. The sample plate is carefully placed under a perspect column with an inside diameter of 7.6 cm. about 1 mt. of height with a mounting flange to conveniently allow the tightening of the sample plate carrying the sample from below by means of screws. Optionally, a mirror is placed under the opening in the sample plate to facilitate observation. The cylinder has a laterally oriented opening of approximately 1 cm. diameter to allow connection to a pump, approximately 1 cm. above the sample when it is mounted. Optionally, a 3-way valve can be mounted on this connection to allow easier emptying of the column after the test. The pump is set to raise the height of the liquid inside the cylinder in 60 + 2 seconds to 25.4 cm.

At the beginning of the pumping, the lower surface of the test specimen is observed. When the drop of the first drop of the test specimen occurs, the pump is immediately stopped, and the height of the column is recorded in units of millimeters. For each material, five tests must be repeated and the results must be averaged.

Proof of Acquisition This test is carried out at approximately 22 +/- 2 ° C and at 35 +/- 15% relative humidity. The synthetic urine used in these test methods is commonly known as Jayco SynUrine and is available from Jayco Pharmaceuticals Company of Camp Hill, Pennsylvania. The formula of synthetic urine is: 2.0 g / l of KCl; 2.0 g / l of Na2SO4; 0.85 g / l of (NH4) H2PO4; 0.15 g / l of (NH4) H2PO4; 0.19 g / l of CaCl2; and 0.23 g / l MgCl2. All these chemicals are reagent grade. The pH of the synthetic urine is within the range of 6.0 to 6.4. Referring to Figure 3, an absorbent structure (410) is loaded with a 75 ml stream of synthetic urine at a rate of 15 ml / s using a pump (Model 7520-00 supplied by Cole Parmer Instruments., Chicago, USA). ), from a height of 5 cm above the surface of the sample. The time to absorb the urine by a chronometer is recorded. The jet is repeated at jet intervals of precisely 5 minutes until the article is sufficiently loaded. The current test data is generated by loading four times. The test sample, which can be a complete absorbent article or an absorbent structure comprising an absorbent core, a topsheet, and a backsheet, is arranged to lie flat on a foam pad 411 inside a perspex box (from which only base 412 is shown). A perspex plate 413 having an opening diameter of 5 cm in its middle part is placed on top of the sample over the load zone of the structure. Synthetic urine is introduced into the sample through a fitted cylinder 414, and stuck in the opening. The electrodes 415 are located on the lowest surface of the plate, in contact with the surface of the absorbent structure 410. The electrodes are placed on the chronometer. The loads 416 are placed on top of the plate to simulate for example a baby's weight. A pressure of about 50 g cm2 (0.7 psi) is achieved by placing weights 416, for example for the MAXI size of 20 kg commonly available. While the test fluid is introduced into the cylinder, it typically accumulates on top of the absorbent structure thus completing an electrical circuit between the electrodes. The test fluid is transported from the pump to the test assembly by means of an 8 mm diameter pipe, which is kept filled with the test fluid. In this way, the fluid starts flowing out of the pipe essentially at the same time the pump starts to operate. At the same time, the stopwatch is also activated, and the stopwatch stops when the absorbent structure has absorbed the urine stream, and the electrical contact between the electrodes is interrupted. The acquisition speed is defined as the volume of the jet absorbed (mi) per unit of time (s). The acquisition speed is calculated for each jet that is introduced into the sample. The first and the last of the four jets are of particular interest in view of the current invention. This test is mainly designed to evaluate the products generally referred to as MAXI size products for a design capacity of around 300 ml, and that have a Final Storage Capacity of approximately 300 ml to approximately 400 ml. Products with significantly different capacities should be evaluated (such as can be anticipated by adult incontinence products), the particular setting of the fluid volume per jet should be appropriately adjusted to approximately 20% of the total design capacity of the article, and the standard protocol deviation from the sample should be recorded.

Re-wetting Method of Collagen After Adjugation (Refer to Figure 4) Before running the test, the collagen film purchased from NATURIN GmbH, Weinhein, Germany, under the designation COFFI and a basis weight of approximately 28g / m2 is prepared, being cut into 90 mm diameter sheets, for example using a device for cutting the sample, and balancing the film in the controlled environment of the test room (see above) for at least 12 hours (tweezers will be used for all manipulations of the collagen film). At least 5 minutes, but no more than 6 minutes after the last jet of the acquisition test above is absorbed, the cover layer and weights are removed, and the test sample (520) is carefully placed flat on a laboratory work table. Four sheets of cut and balanced collagen material (510) are weighed to an accuracy of one milligram, and then placed centered on the loading point of the article, and covered by perspex plate (530) 90 mm in diameter, and about 20 mm thick. A weight (540) of 15 kg (also centered) is carefully added. After 30 +/- 2 seconds the weight and the perspex plate are again carefully removed, and the collagen films are weighed again.

The result of the Collagen Rewet Method after Acquisition is the collection of moisture from the collagen film, expressed in mg. It should also be noted that this test protocol can be easily adjusted according to the specific product types, such as different sizes of baby diapers, or adult incontinence articles, catamenial items, or by variation in type and amount of fluid loading, the amount and size of the absorbent material, or variations in the applicable pressure. Once these relevant parameters have been defined, such modifications will be obvious to one skilled in the art. When the results of the adjusted test protocol are considered, the products can easily be optimizing these relevant parameters identified as in an experiment designed according to standard static methods with realism in the use of boundary conditions.

Tea Bag Centrifugal Capacity Test (CCBT test) Although the CCBT test was developed specifically for superabsorbent materials, it can be easily applied to other absorbent materials. The Centrifugal Capacity test of the Tea Bag measures the values of the Centrifugal Capacity of the Tea Bag, which are a measure of the retention of the liquids in the absorbent materials. The absorbent material is placed inside a "tea bag", immersed in a solution at 0.9% by weight of sodium chloride for 20 minutes, and then centrifuged for 3 minutes. The ratio of the weight of the liquid retained to the initial weight of the dry material is the absorbent capacity of the absorbent material.

Two liters of sodium chloride at 0.9% by weight in distilled water are poured into a tray having dimensions 24 cm X 30 cm X5 cm. The height that fills the liquid should be around 3 cm. The pouch of the tea bag has dimensions of 6.5 cm X 6.5 cm and is available from Teekanne in Dusseldorf, Germany. The pouch is capable of hsealing with a standard kitchen plastic bag sealing device (for example, VACUPACK2 PLUS from Krups, Germany). The tea bag is opened by carefully cutting it partially, and then weighing it. About 0.200 g of the sample of the absorbent material, weighed to the nearest +/- 0.005 g, is placed inside the tea bag. Then, the tea bag is closed with a hsealer. This is called the sample tea bag. An empty tea bag is sealed and used as a white. The sample tea bag and the white tea bag are then placed on the surface of the saline solution, and submerge for approximately five seconds using a spatula to allow complete wetting (the tea bags will float on the surface of the saline solution but then they will be completely wet). The watch is activated immediately. After the soaking time of 20 minutes the sample tea bag and the white tea bag are removed from the saline solution, and placed in a Baunknecht WS130, Bosch 772 NZK096 or equivalent centrifuge (230 mm diameter), of so that each bag adheres to the outer wall of the centrifugal basket. The lid of the centrifuge closes, the centrifuge is turned on, and the speed increases rapidly to 1, 400 rpm. Once the centrifuge stabilizes at 1, 400 rpm the timer is activated. After three minutes, the centrifuge s. The sample tea bag and the white tea bag are removed and weighed separately.

The Tea Bag Centrifugal Capacity (CCBT) for the sample of the absorbent material is calculated as follows: CCBT = ((weight of tea bag after centrifugation) - (weight of white tea bag after centrifugation) - ( weight of dry absorbent material)) / (weight of dry absorbent material). Also, the specific parts of the structures or of the total absorbent articles can be measured, such as cuts "of regions", for example to observe in parts of the structure or of the total article, by where the cut is made through the full width of the article in determined points of the longitudinal axis of the article. In particular, the definition of "crotch region" as described above allows determining the "crotch region capacity". Other cuts can be used to determine a "base capacity" (for example the amount of capacity contained in a unit area of the specific region of the article.) Depending on the size of the area unit (preferably 2 cm by 2 cm) the definitions of how many average is taking place - naturally, the smaller average will occur, the smaller one.

Claims (12)

1. Absorbent article comprising: an absorbent core defining a core region, and a back sheet covering the core region and a chassis region surrounding the core region comprising a back sheet of the chassis, characterized in that in the region of the At the core, the ratio of the PACORM value to the MVTR value of the backsheet is less than 0.028 [mg / (g / m2 / 24h9] and the MVTR value of the backsheet of the chassis region surrounding the core region is higher than the MVTR value of the backsheet of the core region

2. The absorbent article according to claim 1, further characterized in that in the core region the ratio of the PACORM value to the MVTR value is less than 0.019 [mg / (g / m2 / 24h)]

3. The absorbent article according to claim 1 or 2, further characterized in that the MVTR values of the backsheet of the chassis region surrounding the core region are I m are 20% larger than the MVTR values of the backsheet of the core region.

4. The absorbent article according to claim 1 or 3, further characterized in that the BS material covering the core has an air permeability greater than 1500 l / sec / cm2.

The absorbent article according to any of claims 1 to 4, further characterized in that the material covering the core has a liquid impermeability of less than 140 mm in the hydrostatic head test.

6. The absorbent article according to any of claims 1 to 5, further characterized in that the absorbent core has a final storage capacity of at least 75 ml.

7. The absorbent article according to claim 6, further characterized in that the absorbent core has a final storage capacity of at least 90 ml.

The absorbent article according to claim 7, further characterized in that the absorbent core has a final storage capacity of at least 165 ml.

9. The absorbent article according to claim 8, further characterized in that the absorbent core has a final storage capacity of at least 300 ml.

10. The absorbent article according to any of the preceding claims, further characterized in that the chassis comprises backsheet materials with MVTR of more than 4000 g / m2 / 24h.

11. The absorbent article according to any of the preceding claims, further characterized in that the chassis comprises backsheet material having an air permeability of more than 2500 l / sec / cm2.

12. The absorbent article according to any of the preceding claims, further characterized in that the article is a baby diaper or an adult incontinence article.