MXPA00000036A - Disposable absorbent articles with reduced occlusion tendency - Google Patents

Abstract

Disposable absorbent article such as a feminine hygiene pad, and adult incontinence article or a baby diaper having a minimised tendency for creating negative skin occlusion which might create over-hydration of the skin by exhibiting a low Breathability Value as impacted by the vapour permeability of backsheet materials and the respective areas as covered by such materials.

Description

DISPOSABLE ABSORBENT ITEMS WITH REDUCED TENDENCY TO OBSTRUCTION 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 skin ventilation, such as by improved breathability performance.

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 pervious topsheet facing the wearer's body, a backsheet impermeable to the liquid that faces 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 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-O.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-AO 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 webs are either treated or untreated with respect to the improvement of their liquid impermeability properties, as described in European Patent EP-AO 196 654. In the international publication WO 95/16562 a laminate of a non-woven material 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. As well, the 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 particular benefits can be obtained by minimizing the area of impact, selectively combining the materials in certain regions of the article, and in particular exploiting the benefits of the absorbency properties of the absorbent core of the article. 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-O 312 118.

Until now, however, the approach has been to maintain the good condition of the skin, either by helping to maximize the permeability of the materials without affecting in a detrimental way the penetration of the liquid. It has not been sufficiently recognized, however, that there is an interaction between this property of the material and its disposition. It has not been sufficiently recognized that within certain ranges, materials with superior permeability allow greater protection of the area than materials with low permeability. Accordingly, it is an object of the present invention to provide disposable absorbent articles that provide good skin ventilation by improving the breathability of the cover materials such as the backsheets, at the same time minimizing the area covered with the materials, which are an obstacle to transport moisture away from the user's skin during use, thereby minimizing the user's skin obstruction as may be expressed by the Breathability value of the article.

BRIEF DESCRIPTION OF THE INVENTION A disposable absorbent article such as a feminine hygiene pad, an adult incontinence article or a baby diaper, which has a minimized tendency to create negative skin blockage that could create excessive skin hydration by exhibiting a Low Breathability value as it impacts the vapor permeability of the backsheet materials and the respective areas as they are covered by these materials.

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 comprise 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 fastening system generally designated multiple 36. The dual tension fastening system 36 preferably comprises a primary fastening system 38 and a waist closure system 40. The fastening system primary 38 preferably comprises a pair of securing members 42 and a landing member 44. The waist closure system 40 is shown in Figure 1 to preferably comprise a pair of first fastening components 46 and a second fastening component 48. The diaper 20 also preferably comprises a locating patch 50 underlying each first fastening component 46. The diaper 20 is shown in the figure having an outer surface 52 (facing the viewer in Figure 1), an opposite inner surface 54. to the outer surface 52, a first waist region 56, a second waist region 58 opposite the first region n belt 56, and a periphery 60 which is defined by the outer edges of the diaper 20 in which are designated the longitudinal edges 62 and the end edges 64 are designated. The inner surface 54 of the diaper 20 comprises such 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 one portion of the upper sheet 24 and other components attached to the upper sheet 24). The outer surface 52 comprises such 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 centerline 66 of the diaper 20. Each of the waist regions comprises a central region 68 and a pair of side panels typically comprising the outer side portions of the regions of waist. 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 core region and side seams 10.

The outer layers or backsheet 26 are those portions of the chassis 21 or of the absorbent core 22 that will form the exterior of the disposable diapers 20 that is, that they give away from the wearer. 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 the 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 Bewic -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 can be a combination of several absorbent structures, which in turn can consist 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 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, subsequent to the application, thus causing the chemically formed intrafiber crosslinks which can increase the stiffness of the fibers. Although the use of mesh 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 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" can refer to thermoplastic fibers comprising a core fiber made of a polymer that is enclosed within a thermoplastic shell made of a different polymer. The polymer that comprises the shell often melts at a different temperature, typically lower, than that of the polymer comprising the core. 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 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. 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 plies 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 hydrocarbons 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. 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 crosslinked 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 may be used in the form of particles or fibrous form and other elements may 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 stools per period of use resulting in a load of 300 ml, and found to be sufficiently representative evacuation rates of 15 ml / 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 appropriate design capabilities 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 superabsorbent polymers (SAP) 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 ml 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 ml. or less. Catamenial pads often have up to about 20 ml., Articles for light urinary incontinence have, for example, 75 ml. or approximately 90 ml., the articles for medium urinary incontinence, or also the diapers of small babies can have approximately 165 ml., and the diapers of babies that begin to walk reach 300 ml. or more, and articles for severe adult incontinence having 600 ml. 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 ° C. One more way to determine gas permeability is by 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 they prevent the liquids from penetrating. In this way, transport mechanisms are slow flowing in the capillaries. This 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 stages 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 said 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 Permeability range amvtr (q / 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. 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.

Core Operation and 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 method of rewetting with collagen after acquisition (PACORM) has been found to describe this performance well, thus for values of nuclei with low functioning 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. A further important element of the present invention is the area covered by the article and its correlation with the breathability of the cover materials, especially the materials of the backsheet. In the end, it would be desirable to only use these materials, which do not provide an obstacle to the evaporation of moisture from the skin, which would be satisfied by the materials with MVTR results of approximately 12,000 g / m2 / 24h, which corresponds The result of the conforming test is reached when the MVTR test is operated without a test specimen. When this is compared with the aforementioned ranges for the materials that are in accordance with the materials in reality, it becomes clear, that even for these materials to be used as the material of the backsheet this end is not yet reached. In the following, for the given body dimensions of a given object group, both of the chassis region as well as the core region should be, from a breathability and ventilation point of view, of minimum size. However, having the minimum protection of the core skin as required to control the exudates, and having certain requirements for the placement of the absorbed fluid, this minimum size can rarely be satisfied. Within the scope of the present invention, this minimum area of the core is considered to correspond to an area covering the body openings, ie, this minimum area of the core is not considered to be impacted by any of the fluid handling requirements. or stool. In this way, in the case of a pad intended to be used for female urinary incontinence or during menstruation, protection of the vaginal area would be required, corresponding to approximately 2.5 cm. by 4 cm., that is, 10 cm.2. For smaller babies, the opening of the anus also needs to be covered, so this area increases to approximately 50 cm.2. For crawling size babies this minimum area is increased to 5 cm dimensions. by 15 cm. or approximately 75 cm.2, and for items for adult incontinence, this minimum area increases to approximately 100 cm.2. Therefore, the first element of ventilation of an article is like the actual areas compared to the minimum areas. However, assuming that the article covering the body has no limiting effect of evaporation of moisture, this real area can be elevated, as even though it is covered, the skin can be maintained at a low water content. However, the greater impervious to vapor becomes of the roofing materials, the smaller the covered area should be. This inverse correlation is an essential aspect of the present invention, that is, the definition of the value of the breathability of the article (ABV) ABV = (real area / minimum area) * (1 - real MVTR / maximum MVTR) where - ABV is the value of the breathability of the determined article for the material or materials of the back sheet of the respective region (without dimension); - the real area is the respective region of the article [m2 or cm2]; - the minimum area is defined as above (same unit as the real area; - the real MVTR is the value of the wet vapor transmission rate in the method described below [G / M2 / 24H]; - MVTR maximum corresponds to the most value small that a material would need to exhibit so as not to represent any obstacle to the evaporation of moisture from the skin.This corresponds to the result of running the MVTR test without a test material, resulting in a value of 12000 g / m2 / hr. The value of the respirability of the article can be calculated by several regions of the article, that is, for the core regions and for the chassis regions separately, or for different sub regions of these regions where their use materials with different MVTR values As each daily increase protection will have a detrimental effect according to the respective respirability of the back sheet material, the breathability value of the article It can be easily determined by adding the ventilation values of the individual regions. This now allows for ease in applying design criteria for absorbent articles, especially when introducing materials that exhibit vapor permeability at the same time as the dimensions of the articles are varied. In a particular plan, it has been found, that the absorbent articles must have a total breathability value of the article of less than 1, preferably less than 13 or even more preferably less than 11. When starting from a known article design, which does not satisfy the requirement, the designer can now reduce any of the area covered by the breathability or both to carry the appropriate values. Since the minimum area is not dependent on the liquid handling requirements, it is certainly desirable to reduce the actual size of the core to allow protection of the smaller area. This can be achieved by using absorbent cores with high performance as described above, which allows for much more efficient core designs, including the ability to place relatively high amounts of absorbency in relatively small areas without too much compromise of runoff, core efficiency, or the operation of rewetting and dryness of the skin. When applied to lightweight adult incontinence articles, these designs can yield a theoretical final storage capacity of 90 ml. in an area of 100 cm2, that is, these articles would have a "base capacity" of 0.9 ml / cm2. The item for a moderately incontinent person may have a base capacity of 165 ml. per 100 cm.2, or 1.65 ml / cm2. For people with severe incontinence as well as for babies who start to crawl, the 300 ml capacities may be very desirable. for an area of 100 cm.2 square corresponding to 3 ml / cm2. The same principle applies to the chassis region, as the need to fix the article on the user and also maintain its position during use that requires some protection of the user's skin. There is a well-known exchange between the forces that need to be transmitted to the surface of the user's body and the area over which these forces are applied. This essentially results in a pressure exerted on the skin. Therefore, from a point of view, larger areas would be desirable, however, if the materials covering the body over these larger areas are not sufficiently vapor permeable, skin clogging may occur, resulting in deleterious effects. on the skin as excess hydration and the resulting skin irritation.

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

The basis for the various samples is a commercially available product, PAMPERS Baby Dry Plus size Maxi / MAXI PLUS as marketed by Procter & Gamble in Europe. This product a core area, as defined here of 577 m2 and a cis area excluding the overlap of 561 cm2. For the test, the core been modified by the following steps: First, the chemically treated cellulosic hardened material (CS) supplied by Weyerhaeuser Co., E.U.A. under the commercial designation "CMC" which functions as an acquisition / distribution layer a basis weight of approximately 500 g / m2. Second, an additional acquisition layer is introduced between the top sheet and the chemically treated, hardened cellulose layer, essentially a chemically bonded, high-floor non-woven material as supplied by FIBERTECH, North America under the designation type 6852. This is a chemically bonded PET fiber web of a basis weight of 42 grams per meter 2 and a width of 110 ml over the total length of the absorbent core. Third, the cellulose material used within the storage core below the chemically treated, hardened cellulosic material is reduced to approximately 11.5 g. per pad. Fourth, the amount of the suberabsorbent material within the 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 products have also been modified to produce the following samples: Examples 1 to 4 as well as comparative examples 1 to 4 are related to baby diapers, thus having a minimum area of 50 cm2.

For example 1, the backsheet of conventional PE been replaced by a non-woven material, especially a hydrophobic carded PP web, with a basis weight of 27 gr. per meter 2, as supplied by SANDLER Gmbh, Scwarzenbachk RFA, under the trade designation VP 39522. In the center of the article, a strip of microporous film having a medium vapor permeability level, as supplied by MITSUI TOATSU , Japan, under the designation ESPOIRE NOT been laminated with glue on the core oriented side of the nonwoven material, to cover the core region. For the example, a different microporous film was used, especially EXXAIRE supplied by EXXON Chemical Co., Ill, E.U.A. In Example 3, the non-woven material been replaced by a highly permeable, hydrophobic spun PP ply of approximately 18 grams. per mt.2 of base weight as supplied by COROVIN GmbH, Peine, RFA, under the designation COROSOFT. In contrast to these examples, the following comparative examples do not meet the criteria as shown here. Comparative example 1 uses the conventional PE film backsheet of the commercialized PAMPERS BABYDRY product. Comparative Example 2 this complete back sheet replaced by a film as used in Example 1 for the center strip. Comparative Example 3 is a commercially available product such as that marketed by Kimberly-Clark under the trade name HUGGIES size 4 in the United Kingdom. As for the materials of the backsheet, the product a non-woven material on the outside and the core region covered by a microporous film. Since the microporous film extends into the cis region, the MVTR article to be separated into three regions, the core region and two cis regions. Alternatively, the MVTR valued for the total cis region can be averaged using relative area weighting factors. Comparative Example 3 a core region area of approximately 696 cm 2, and approximately 386 cm 2 for the entire region of the cis.

TABLE 2 MVTR values Breathability value [g / m2 / 24h] [-] core chassis Example 1 3800 4500 14.9 Example 2 4500 4500 14.2 Example 3 4500 6000 12.8 Comparative example 1 200 200 22.4 Comparative example 2 3800 3800 15.6 Comparative example 3 2000 4500 16.4 Although these examples showed the beneficial aspect and use highly breathable materials, the following explains the effect of the area in combination with breathability. Comparative Example 4 is a commercially available product as sold by Procter & Gamble under the brand name of PAMPERS Comfort, size L, in the Philippines. This essentially consists of a rectangular core covered by a rectangular rear sheet with two mechanically activated lugs comprising tape fastening means fixed thereto. The backsheet material is the conventional PE film, covering a core area of approximately 302 cm2 and a chassis area of approximately 564 cm2. Example 4 shows the effect of using a film with high breathing capacity as used in example 2 as a total replacement of the material of the backsheet.

TABLE 3 MVTR values Respirability value [g / m2 / 24h] [-] chassis core Example 4 4500 4500 10.8 Comparative example 4 200 200 17.0 To further illustrate the effect on the articles of different users, the following products have been investigated: The following example is also based on a currently marketed adult incontinence product, as sold by Procter & Gamble under the trade designation ATTENDS BRIEF MÉDIUM IP in several European countries such as Germany. This product has an essentially rectangular core with small sections cut from the leg in the crotch region, of an area of approximately 1265 cm2. The area of the chassis region is, excluding the overlap during use, of approximately 2820 cm2. Therefore, when considering the maximum overlap (as defined by the distance between the rear tape ends on the front side which is approximately 10 cm.) The total area of the chassis region amounts to approximately 1425 cm2. As explained in the above, for these products a minimum area of 100 centimeters is being applied. This product does not by far satisfy the criterion of the present invention, as can be seen from comparative example 5.

In order to improve the ventilation of this product, the present invention allows to follow and balance the two approaches, especially by modifying the vapor permeability and / or in the covered area. Example 5 shows the first effect, ie, increasing the vapor permeability of the materials without changing the area using a design and materials in analogy to example 3. Example 6 shows the effect of reducing both the areas of the core region and from the chassis region to 1200 cm2, and using the same highly breathable film material of Example 3 or 5 for both the core and the chassis region.

TABLE 4 MVTR values Respirability value [g / m2 / 24h] H Core Chassis Example 5 4500 6000 15.0 Example 6 4500 4500 13.5 Example 5 200 200 26.5 At the other extreme, a feminine hygiene product as sold under the trade name ALWAYS ULTRA PLUS by Procter & Gamble from several countries in Europe, has a core region area of approximately 141 cm2, and an area of the surrounding chassis region of approximately 55 cm2, whereby the so-called "wings" that are folded around the undergarment of the wearer are treated therein as the "overlap" for the above diapers (in this way the "chassis" region consists essentially of a 1 cm wide ring encircling the core). This product, as shown in Comparative Example 6 also does not satisfy the present requirements. In example 7, however, with a vapor-permeable film as in the example it would do in this manner, for example using a reusable film as in example 2.

TABLE 5 MVTR values Respirability values [G / M2 / 24H] H Core Chassis Example 7 4500 4500 12.3 Comparative example 5 200 200 ... 19.3 PROOF PROCEDURES Determination of the area The following describes a suitable method for determining the areas and / or subareas of the absorbent articles. However, you can use other methods such as measuring the dimensions and then calculating the areas, if applicable in the same meaning. The articles under evaluation are placed flat under light tension to straight stretch the elasticizing characteristics on a flat surface, preferably on a "light box" with illumination through the article from the bottom. If necessary, the edges can be tapered to more accurately allow the flattening of the elastic characteristics, provided that the contour below the belt is still discernible. In the case of articles such as "lifting" or "short", the side seams are carefully cut. The area of the respective regions can then be conveniently measured by placing a sufficiently large piece of paper of known and uniform basis weight on the article, and then marking the boundaries of the regions. After the cut and provided the exact weight, the weight of the sheet of paper, which dividing through the base weight, results from the area of the paper and in the future from the respective region. Depending on the design of the article, only the core and chassis areas are evaluated, or, if both consist of subregions that comprise materials from the back sheet with different vapor permeabilities, all the respective sub-areas can be evaluated. For articles that have a substantial overlap of the front and back ears during use, ie in the "closed" arrangement in the user, additional regions are marked on the article by symmetrically closing the article to create a circumference that corresponds to the average circumference of the user group attempted. For baby diapers, the following dimensions of the waist circumference of a baby standing on the navel have been found to be adequately representative: Table 6 Babies MINI (4 to 6 kg) 49.8 cm Babies MIDI (6 to 9 kg) 42.7 cm Babies MAXI (9 to 18 kg) 45.5 cm Babies Junior (18 to 27 kg) 48.5 cm For other applications, such as items for adult incontinence, or other intermediate sizes, the respective data can be easily generated. For articles that comprise stretch members, the circumference must be adjusted to represent the typical forces of use. When closing the article to create the respective circumference, the overlap edges are marked using a suitable marker, and the overlap area will be considered to have the lowest MVTR value of its components.

Wet 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 for equalizing the opening of the cylinder can be fixed by screws, and a silicone rubber sealing ring, equal to the internal diameter, fits 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 material is CaC12, as may 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 ° C 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 about 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 cm2 ring is used, the sample must be at least 55 mm. wide, for the ring of 5 cm2 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 releasing operation, thus beginning 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.

Liquid Impermeability (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. Upon the occurrence of the drop of the first drop of the test specimen, 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 / I 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 stopwatch. 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 (ml) 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 which 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.

Collagen Rewet Method after Acquisition (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 heat sealing 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 heat sealer. 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 stopwatch 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 up to 1,400 rpm. Once the centrifuge stabilizes at 1, 400 rpm the timer is activated. After three minutes, the centrifuge stops. 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 (18)

1. Disposable absorbent article comprising an absorbent core that covers at least the body openings that release exudates from the wearer's body during use, defining a core region and a chassis region surrounding the core region, whereby the region The core and the chassis region comprise materials of the backsheet characterized in that the article has a Breathability Value of less than 15.

The disposable absorbent article according to claim 1, further characterized in that the Breathability Value of the Article is less than 13.

The disposable absorbent article according to claim 1, further characterized in that the Breathability Value of the article is less than 11.

The disposable absorbent article according to any of claims 1 to 3, further characterized in that the disposable absorbent article has an average base capacity of the core or of more than 90 ml per 100 cm2.

5. The disposable absorbent article according to claim 4, further characterized in that the disposable absorbent article has a core average core capacity of more than 165 ml per 100 cm2.

The disposable absorbent article according to claim 5, further characterized in that the disposable absorbent article has a core average core capacity of more than 300 ml per 100 cm2.

The disposable absorbent article according to any of the preceding claims, further characterized in that the backsheet comprises materials having MVTR of more than about 200 g / m2 / 24hr.

8. The disposable absorbent article according to any of the preceding claims, further characterized in that the backsheet comprises materials having MVTR of at least about 2000 g / m2 / 24hr.

The disposable absorbent article according to any of the preceding claims, further characterized in that the backsheet comprises materials having MVTR of at least about 4000 g / m2 / 24hr.

The disposable absorbent article according to any of the preceding claims, further characterized in that the backsheet comprises materials having MVTR of more than about 6000 g / m2 / 24hr.

The disposable absorbent article according to any of the preceding claims, further characterized in that the materials of the backsheet of the core and of the chassis comprise at least one layer of unitary material extending both towards the core and towards the region of chassis.

12. The disposable absorbent article according to any of the preceding claims, further characterized in that the backsheet material of the chassis region has a value of MVTR greater than the value of MVTR of the backsheet material of the backsheet region. core.

The disposable absorbent article according to any of the preceding claims, further characterized in that article has a rewet performance with a PACORM value of less than about 80 mg.

The disposable absorbent article according to any of the preceding claims, further characterized in that the article is a pad for feminine hygiene.

15. The disposable absorbent article according to any of the preceding claims, further characterized in that the article is a baby diaper.

16. The disposable absorbent article according to claim 15, further characterized in that the diaper further comprises fastening means for releasably closing the front and rear waist regions around the wearer's waist portion during use.

The disposable absorbent article according to claim 15, further characterized in that the diaper is of the "lifting" type, having sealed side seams combining the front and rear waist portions as it is attempted to be placed around the waist of the user.

18. The disposable absorbent article according to any of the preceding claims, further characterized in that the article is a product for adult incontinence.