MXPA00000309A - Disposable absorbent articles with clothlike feel backsheet having zoned breathability and process for making such backsheets - Google Patents

Abstract

A disposable absorbent article comprising a breathable polymeric film at least partially combined with a fibrous material to a laminated for being used as backsheet material with zones having different breathability.

Description

DISPOSABLE ABSORBENT ARTICLES WITH REAR LEAF WITH SENSATION SIMILAR TO THE FABRIC THAT HAS BREATHABLE IN ZONES AND PROCESS FOR DEVELOPING THE SUBSEQUENT LEAVES FIELD OF THE INVENTION The present invention relates to disposable absorbent articles such as baby diapers, incontinence articles, sanitary napkins and the like, and in particular to baby diapers and incontinence articles articles having backsheets with a fabric-like feel and particular breathability.

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 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 also It can, beyond 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, potentially inducing over-hydration in this way. the skin, particularly 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-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. Breathable materials for use in various articles 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 property of " microporosity "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.

It is also known to combine said films with non-woven materials, as described in the international publication WO 97/15442, wherein the polymeric films containing fillers such as calcium carbonate are coated by extrusion on a non-woven web. which has a wider width than the film, whereby the breathability of the film is created by interdigitation stretching. Nevertheless, the prior art did not recognize the benefits that arise when using a backsheet material comprising a breathable film material having different degrees of breathability in different areas thereof, in particular when at least one of these regions also comprises a material fibrous that provides improved handling and feel. Accordingly, it is an object of the present invention to provide a disposable absorbent article comprising an absorbent core defining a core region, a chassis region surrounding the core region, a backsheet material comprising at least the core region a laminate comprising a film material or similar to the gas or vapor permeable film, and further comprising a fibrous layer; whereby at least one layer of polymeric film of the backsheet of the core and the backsheet of the chassis is unitary on both regions, and by means of which the material of the backsheet in the core region has a lower breathability as expresses by the values of MVTR that the material of the back sheet in the region of the chassis. It is a further object of the present invention to provide a process for making such a backsheet for use in said article by combining a filled film with a narrower strip of nonwoven material, then interdigitally activating the laminate, either with uniform conditions of activation across the full width, thus creating non-uniform breathability in the laminate and pure areas of the film, or with non-uniform conditions of activation, thus increasing the difference in breathability between the two zones. It is even an object more to provide materials as they are made through this process.

BRIEF DESCRIPTION OF THE INVENTION A disposable absorbent article comprising a breathable polymeric film at least partially combined with a fibrous material for a laminate that is used as the backsheet material with zones having different breathability.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is schematically showing a baby diaper with ribbons as an example of absorbent article. Figure 2 shows a schematic diagram of an apparatus that can be used in a preferred embodiment of the pressure applying stretch equipment. Figure 3 schematically shows a cross section through the apparatus.

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 placed against or in proximity to the body of the user 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 dual tension clamping system 36 preferably comprises a system of primary fastener 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 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 localized positioning patch 50 underlying each first fastening component 46. The diaper 20 is shown in 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 one portion of the upper sheet 24 and other components attached to the upper sheet 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 back sheet 26 and other components attached to the back sheet 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 central region 68. 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 (direction x or width) is defined as the direction parallel to the lateral center line 66 of the diaper 20, the longitudinal direction (direction and length) being defined as the direction parallel to the longitudinal center line 67, and the axial direction (thickness direction) 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 can 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 elastic separation member 86 as described in the aforementioned US 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, positioned 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 upper sheet 24 and the sheet back 26 and elastic member 77 positioned between backsheet 26 and elastomeric member 76. This as well as other components of the diaper are given in more detail in international publication WO 93/16669 which is incorporated herein by reference. 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). The absorbent core can be a unitary core structure, or it 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 a extension essentially of two dimensions (that is, being of one layer) or a three-dimensional shape. 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. These 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; Patent Application Copending the United States with Serial Number 08 / 542,497, filed on 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. 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 polymer materials are also commonly referred to as materials "hydrocolloids" or "superabsorbents". These hydrogel-forming absorbent polymers preferably have a multiplicity of anionic, functional groups, such as sulfonic acid, and more typically carboxy groups. The most preferred polymer materials for use in the manufacture 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).

Materials of the Breathable Back Blade An essential element of the present invention are materials that are permeable to gas, such as air, or to vapor, such as water vapor. Permeability can be determined by the rate of humid steam transmission (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 absorption moisture of calcium chloride through the test specimen under a relative humidity of 75% at 40 ° O- The conventional examples of these materials are the so-called microporous films, as 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. Preferred executions of these films are currently produced by a number of film-making companies, specific examples are supplied by MITSUI TOATSU, Japan, under the designation ESPOIRE NO, which has, at a basis weight of approximately 30 gm2, a value of MVTR of approximately 3800 g / 24h / m2. A still higher breathability is exhibited by a film supplied by EXXON Chemical Co., Ill, USA, under the designation EXXAIRE, having at a basis weight of 30 gm2 an MVTR result of about 4500 g / 24h / m2. Within the context of the present description, the films manufactured or treated as described above can be classified as follows: TABLE 1 Permeability Ranao MVTR (q / m2 / 24h Not permeable up to 200 approximately Low permeability up to 2000 approximately Average permeability up to approximately 4000 High permeability up to approximately 6000 Very high permeability over 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 operating the MVTR test without a test material. In order to improve the feeling similar to the preferred fabric of these films, these can be and are often combined with fibrous webs, such as non-woven materials, which will be placed towards the outer side of the article, that is, over the side of the garment. These fibrous webs may be non-woven materials, such as, but not limited to, carded or spunbonded webs of polypropylene, polyethylene, thermally bonded or chemically bonded webs. Since these wefts are often more expensive than the film materials, it will be desired to apply these wefts only where they are required to provide the feel similar to the fabric or garment, especially in the region that extends essentially with the core region. The preferred non-woven materials are supplied by SANDLER GmbH, Schwarzenbach, RFA, under the designation VP3952, which is a thermally bonded, carded polypropylene web of 27 g / m2. The non-woven material can be combined with the film materials by conventional lamination steps, such as adhesive lamination using spray applicators, or gravure applicators, grooved-side applicators and the like. Or, the materials can be combined by melting at least one component of at least one of preferably both of the two materials to be laminated, or by thermal or heat lamination, dynamic or ultrasonic laminators, or extrusion lamination. A key element of the present invention is to combine the film and the fibrous material into a composite material before the film is "activated" to be breathable. This deformation can be achieved by a number of different ways, in the machine direction of the material such as the conventional stretch between two grip roller arrangements running at a differential speed, or in directions transverse to the machine such as by setting the edges of the material are tensioned in divergent frames, or by running it through a narrower internal gear roller, 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 often at a temperature greater than about 40 ° C), or "cold", that is, below that temperature. A particularly suitable process according to the present invention is to treat the composite materials comprising the laminated and unlaminated materials as discussed above by feeding the starting material, referred to as the screen in the following, through at least two rollers each one with circumferential grooves and ridges, which are moved such that the shoulders and grooves are "engaging" as described herein in a narrow tolerance that the web is subjected to permanent deformation, thus providing the mechanical treatment of the web . Similar processes have been developed for treating stretch laminate materials and are described in U.S. Patent 5,167,897 (Weber) relating to stretch materials. Referring to FIGS. 2 and 3, the essentially unstressed raw material 201 is directed through a stretch system of the raster in the transverse direction 220 which employs opposite pressure applicators having three-dimensional surfaces, which at least to one degree are complementary to each other. In a preferred embodiment the weft 201 is guided by the guide rollers 211 and 212 to pass between the ridges and the grooves of the surface 222 of a higher corrugated roll 221 and the respective internal gear grooves and shoulders of the surface 222 of the Lowermost Corrugated Roller 225. Although the exact configuration, geometry, spacing and depth of the ridges and complementary grooves in the higher and lower corrugated rollers will vary, depending on factors such as the amount of tensioning desired in the weft and the properties of the weft itself, such as the basis weight and the elasticity, a specific preferred embodiment has an essentially rectangular profile as indicated schematically in Figure 2, wherewith, such as for the treatment of a weft having a basis weight of approximately 25 g / m2 of film and 27 g / m2 of non-woven material, the slots 231 have a width 232 of 1 mi., the shoulders 235 have a width 36 of 0.6 mi., a distance 237 from the bottom of the grooves to the peaks of the shoulders of approximately 8 mm, and, both the edges and the corners and indicate by 238, the uniform radius of approximately 0.1 mi. Also indicated in Figure 3 is the cross section of the weft 201. For wefts having different properties, these dimensions must be adopted appropriately, with which it has been found advantageous to have the width 236 of the shoulders 235 so that be between 30% and 90% of the width 232 of the slots 231, preferably between 50% and 70%. The degree of overlap 239 of the opposite peaks on the corrugated rolls can, of course, be adjusted as desired, to produce more or less mechanical treatment concentrated in the weft. The maximum overlap 239 is dictated by operating restrictions, such as the effective running of a piece of equipment, and by the properties of the material, which could result in the perforation or cutting of the weft in too concentrated a treatment. The minimum overlap 239 is defined by the limitation that the frame is actually treated mechanically. This requires that the distance of the corrugated rolls, which are arranged so that they can mesh internally if the distance would be narrow, is less than the size of the weft.

Then, the "overlap" as used herein, is less than 0, and the lower limit of the overlap to be useful in the present invention is about -100%. Preferably, however, the overlap must be significantly greater than -15% and for particularly preferred executions it amounts to several hundred percent or even more than 1000%. The materials of the corrugated rolls 221 and 225 can be any suitable material that allows for proper formation and that will resist the pressure exerted by the rolls on the material, such as metals, aluminum alloys or steel. In the case of very low or very high friction between the weft and the rollers, the surface of the Roller can be roughened or smoothed or otherwise treated to prevent the weft from sliding between the corrugation or not penetrating sufficiently in the corrugations. It is also recognized that although a preferred embodiment comprises a pair of gear corrugating rollers having their corrugations aligned substantially parallel to one another, the present invention can also be practiced employing pairs of corrugated rolls, wherein the corrugations are not all oriented parallel one another Moreover, the corrugation on these pairs of corrugated rolls need not necessarily be aligned parallel to either the machine direction or the transverse direction of the machine. Although this has been described with reference to a preferred profile 230, other profiles may be used. The grooves and ridges may be in a triangular, trapezoidal, or more rounded form, for example, in the sinusoidal form, or any other form that allows the internal gearing of the two rollers. Obviously, for these arrangements, other preferred dimensions can easily be elaborated for optimal operation. Although a presently preferred embodiment has a uniform arrangement of the ridges and grooves in both the circumferential and axial directions of the corrugated rolls, the specific executions may comprise regions with different patterns, this being in an axial arrangement, for example, widths of the grooves and / or the shoulders changing through the axial direction of the rollers, or they are in the circumferential direction, i.e. the ridges and grooves have a changing depth across the circumference of at least one roller, or at least one of the rollers has a macroscopically curved shape, for example, is thicker in the central portion than towards the edges. These applications induce then either to strips or respirability zones oriented in the machine direction, and / or regions with different degrees of respirability oriented in the transverse direction. Also, the use of more than two corrugated rolls can be beneficial, such as when treatment too concentrated in one stage is avoided. Thus, an additional roller of the characteristics of the roller 225 can be placed in such a way that its corrugations also mesh internally with the corrugations of the roller 221. Although the corrugations of this roller must be aligned with the corrugations of the roller 225, the of the internal gear may be different or, within the limitations of the alignment, the shape of the corrugations may be different, such as having different spokes of the ridges and grooves. Of course, it can also be contemplated to have more than two rollers, or two sets of roller pairs 221 and 225, and other combinations of these arrangements. In addition to the treatment described, the weft can also be stretched longitudinally in the machine direction, either in a separate stage of the process before or after the stretch in the transverse direction or integrated in the process itself. A further improvement of the process can be achieved by adding a stage of the frame heating process, either by a separate step of the process directly after the post-formation treatment as disclosed in the above, or by heating the means applying the mechanical stress to the weft, for example, one or both of the corrugated rolls. Preferably, this is applied for the frames comprising materials capable of thermal melting (such as the materials comprise thermoplastic fibers). The beneficial effect of this additional heat treatment either in that the wefts can be formed in such a way as to allow relatively easy plastic deformation by the mechanical process and achieve an elasticity, stability, resistance or uniformity desired by curing with heat. It is further recognized that while the preferred process disclosed herein employs gear-cylindrical cylindrical rollers, the present invention can also be carried out using an intermittent stamping operation employing gear plates to stretch the weft in question in an increased manner. . Through this treatment, breathability will be imparted to the composite material, to a different degree for its various regions or zones. In particular, the nonwoven film laminate region will have lower activation energy available for the deformation of the film, since the fibrous layer will also be deformed. In this way the materials useful for the present invention can be made starting from the same bases as the conventional breathable films that are made of, for example, materials filled with calcium carbonate, as described in the PCT patent application. WO 97/1544, or as they are made as precursors for the aforementioned films. However, in contrast to these conventional films, the films that are to be used in the absorbent articles according to the present invention are not activated to be subsequently optionally combined with a non-woven material, but are first combined to be then activated. A specific example, a polyethylene film with calcium carbonate filler as available from Clopay Plástic Product Company Inc., Cincinnati, USA, under the designation 9704250 combined with the freshly extruded film material is still above its point temperature. of softening to be easily bonded with heat with a two-component, spunbonded, 23 g / m 2 weft, having a polyethylene shell and a polypropylene core such as supplied by SANSEKI Co., Japan. The width of the film can be a typical width of a baby diaper, such as approximately 330 ml., The width of the nonwoven material can be approximately 150 ml., Positioned in a film-centered manner. By treating this film in a manner as described above, it will then result in MVTR values of approximately 1700 g / 24hr / m2 in the area of film / nonwoven laminate, and approximately 2100 in areas having non-woven films. Laminated non-woven material. If the fibrous layer is applied in a striplike manner, and uniform activation conditions are chosen across the width of the activator, the different amount of materials as run through in the essentially equal process arrangements will result in imparting respirability. superior in areas that do not have woven material. In view of the compatibility with the designs as described below, the different zones must have a difference of at least 20% when they are related to the lower value. In absolute terms, the different one is preferably greater than 500 g / m2 / 24h. For example, the treatment may result in an increased MVTR result, for example having 1000 g / 24hr / m2 in the laminated zone, and more than approximately 1600 g / 24hr / m2 in the other zones, or 1500 g / 24hr / m2 in the laminated area and 2200 in the other zone. In the case of the fibrous layer and the film layer which are essentially coextensive, a different degree of breathability can be obtained by different treatment conditions in the different zones, such as having about twice the amount of activation teeth in one area. zone as compared to the other. These zones can also represent regions with continuously changing activation and consequently respirability values instead of the changes that arise in the stage.

In a further embodiment, the placement of the fibrous layer in the zones or strips can be combined with the difference in treatment. In a further aspect of the present invention, the respectively laminated films as discussed above, may be further combined with other materials that do not adversely affect the effects of breathability as imparted by the treatment, such as with other non-woven materials, which additionally provide the benefits for improved soft feeling.

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 toward the user's garments, which are generally referred to as the backsheet. 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 clogging 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 meet the specific requirements of liquid impermeability. 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. Within the definition of the materials that cover certain regions of the article, it must be distinguished, that a material of the posterior sheet that covers the core can extend a little towards the chassis region. For example, if the core covering material is made from a continuous roll, it may very well be that the material of the region covering the core is made of a material similar to the strip of the core width, either exactly or a little wider in the case of a rectangular core, or covering most of the critical areas of the core if it is not rectangular in shape, and this strip extends towards the flat end region of the article, that is, to throughout the total length of the article.

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 that has 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, 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 desiccant material is CaCI2, such as may be sold from Wako Puré Chemical Industries Ltd., Richmond, VA, USA, under the product designation 030-00525. If kept inside a closed bottle, this 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 replicas 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 the 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 .

Claims (20)

1. Absorbent article comprising an absorbent core defining a core region; a chassis region surrounding said core; an absorbent core that is interposed between a back sheet, which is impermeable to liquids, and an upper sheet, which is permeable to liquids; said backsheet extending over the region of the core and at least part of the region of the chassis, said backsheet further comprising a fibrous layer at least in the core region; characterized in that the backsheet comprises a film or film-like layer which is permeable to vapors or gases, which is a unitary layer extending both towards the core region and at least towards part of the region of chassis, whereby the backsheet has a higher MVTR value in these parts of the chassis region, comprising said film or film-like layer, than the backsheet in the core region, which comprises said layer of film or similar to the film in the fibrous layer.

2. An absorbent article according to claim 1, wherein the film or film-like layer is wider than the fibrous layer.

3. The absorbent article according to claim 1 or 2, further characterized in that the backsheet material in the core region has an MVTR of at least 500 g / 24hr / m2.

4. The absorbent article according to claim 3, further characterized in that the backsheet material in the core region has an MVTR of at least 1500 g / 24hr / m2. The absorbent article according to any of claims 1 to 4, further characterized by the MVTR values of the sheet Subsequent in the chassis region are at least 20% higher than the MVTR values of the backsheet in the core region. The absorbent article according to any of claims 1 to 4, further characterized in that the MVTR values of the backsheet in the chassis region are at least 500 g / 24hr / m2 higher than the MVTR values of the backsheet in the core region. The absorbent article according to any of the preceding claims, by means of which said film or film-like layer comprises a polymeric matrix and a material filled with particles embedded within said matrix. 8. An absorbent article according to claim 7, by means of which the filling material is calcium carbonate. The absorbent article according to any of the preceding claims, by means of which the film layer or the film-like layer in the region of the chassis has a basis weight of less than 50 gm2. 10. An absorbent article according to any of the preceding claims, by means of which the backsheet has a basis weight of 70 gm2 where said film or film-like layer and said fibrous layer are comprised. 11. An absorbent article according to any of the preceding claims, by means of which the fibrous layer is a non-woven web. 12. An absorbent article according to any of the preceding claims, by means of which the film or film-like layer and the fibrous layer are combined by thermal bonding or fusion bonding. 13. An absorbent article in accordance with any of the preceding claims, by means of which the film or film-like layer and the fibrous layer are combined by extrusion coating. 14. An absorbent article according to any of the preceding claims, by means of which the film or film-like layer and the fibrous layer are combined by adhesive. 1

5. The absorbent article according to any of the preceding claims, by means of which the article is a baby diaper or an adult incontinence article. 1

6. A process for inducing vapor or gas permeability in areas in a laminate that is used as a backsheet in a product according to any of the preceding claims, comprising the steps of: providing a polymeric film comprising filler embedded particles inside the polymer matrix; providing a fibrous web that has an equal width or is narrower than the film in the transverse direction of the machine; combine the film and the weft to form a laminate; stretching the laminated and non-laminated film areas by feeding the film and laminate zones between a pair of opposed pressure applicators comprising three-dimensional surfaces, which are complementary to each other; and subjecting parts of the weft located between the opposing pressure applicators to the incremental elongation in the transverse dimension causing said three-dimensional surfaces of the pressure applicators to mesh with each other, whereby the area of the laminated and unlaminated film is at least partially permanently deformed and the gas or vapor permeability is induced differently in several areas thereof. 1

7. A process according to claim 16, by means of which the fibrous web is narrower than the polymeric film in the transverse direction of the machine. 1

8. A process according to claim 16 or 17, further comprising the step of thermally treating the web after having subjected the web to said incremental step in the transverse direction. 1

9. A process according to any of the claims 16 to 18, by means of which the internal gear between the two pressure-applying rollers is essentially constant over the entire width of the laminated and non-laminated areas. 20. A process according to claim 16, by means of which the internal gear between the two pressure applicators is different in all the different zones.