MXPA98002481A - Method for selectively perforating a non-woven frame - Google Patents

Abstract

The present invention relates to a method for selectively perforating a nonwoven web (102). A non-woven web (102) is attenuated along a plurality of locations and then a tensioning force is applied to the non-woven web (102) causing the non-woven web (102) to break into the plurality of attenuated locations, a plurality of openings in the nonwoven web (102) that coincide with the attenuated locations

Description

METHOD FOR SELECTIVELY PERFORATING A NON-WOVEN FRAME FIELD OF THE INVENTION The present invention relates to nonwoven webs with openings and a method for making same. Nonwoven webs with openings are particularly well suited for use in disposable absorbent articles such as diapers, incontinence briefs, training pants, feminine hygiene garments and the like.

BACKGROUND OF THE INVENTION Non-woven webs formed through non-woven extrusion processes such as, for example, meltblowing processes and spunbonding processes, can be fabricated into non-expensive products and product components that the products can be considered as Disposable after only one use or few uses. Representative examples of such products include disposable absorbent articles, such as diapers, incontinence briefs, trainers, female sanitary ware, and the like. Babies and other incontinent individuals use disposable absorbent articles, such as diapers, to receive and contain urine and other exudates from the body. The absorbent articles function both to contain the discarded materials and to isolate these materials from the wearer's body and from the wearer's garments and bedding. Disposable absorbent articles having many basic designs are well known in the art. A typical absorbent article includes a liquid-permeable topsheet, a liquid-impermeable backsheet attached to the topsheet, and an absorbent core positioned between the topsheet and the backsheet. Non-woven wefts are usually used as top sheets on disposable absorbent articles as they are permeable to liquid and provide a comfortable surface to the skin. However, in certain uses the non-woven wefts do not work as well as a top sheet, since the exudates of the body sometimes hang or become trapped in the non-woven weft and thus, are trapped in the wearer's skin. A solution to the aforementioned problem is to provide openings in the woven web, so that exudates from the body can easily penetrate through the nonwoven web and into the underlying absorbent core. Unfortunately, certain techniques used to form non-woven screens with openings are either very expensive, create an undesirable roughness sensation against the user's skin, or break, particularly when the non-woven fabric with openings is to be used as a sheet. top on a disposable absorbent article. As used herein, the term "non-woven web" refers to a web having a structure of individual fibers or threads, which are interlaced, but not in any regular, repeating manner. The non-woven webs have, in the past, been formed through a variety of processes, such as, for example, meltblowing processes, spinning bonding processes and bonded carded web processes. As used herein, the term "microfibers" refers to small diameter fibers that have an average diameter no greater than about 100 microns.

As used herein, the term "melt blown fibers" refers to fibers formed by extruding a molten thermoplastic material through a plurality of fine die capillaries, usually circular, such as fused filaments or filaments, to through a stream of gas (eg, air) at high speed, which attenuates the filaments of molten thermoplastic material to reduce its diameter, which can be to a microfiber diameter. Then, the fibers blown under melting are carried through the gas stream at high speed and are deposited on a collection surface to form a web of randomly dispersed melt blown fibers. As used in this, the term "spunbond fiber", refers to fibers of small diameter, which are formed by extruding a molten thermoplastic material as filaments, from a plurality of thin, usually circular capillaries of a spinner with the diameter of the filaments extruded after being rapidly reduced, for example, by means of eductive stretching or other well-known splicing mechanisms. As used herein, the term "polymer" generally includes, but is not limited to, homopolymers, copolymers, such as, for example, block, graft, random and alternating copolymers, terpolymers, etc., and mixtures and its modifications. In addition, unless otherwise specifically limited, the term "polymer" must include all possible geometric configurations of the material. These configurations include, but are not limited to, isotactic, syndiotactic and random symmetries. As used herein, the term "elastic" refers to any material which, after the application of a diverting force, is stretchable, i.e. stretchable, at least about 60% (i.e. stretched, deflected length, which is at least approximately 160% of its relaxed non-deflected length), and which, will recover at least 55% of its elongation after releasing the stretching force, elongation. A hypothetical example could be a 2.54 cm sample of a material, which can be elongated to at least 4,064 cm, and which, after being lengthened to 4,064 cm and released, will recover to a length of no more than 3.2258 cm. Many elastic materials can be lengthened to more than 60% (ie, much more than 160% of their relaxed length), for example, lengthened to 100% or more, and many of these materials will recover to substantially their initial relaxed length. , for example, at 150% of its initial relaxed length, after releasing the stretching force. As used herein, the term "non-elastic" refers to any material, which does not fall within the definition of "elastic" above. As used herein, the term "extensible" refers to any material that, after application of a diverting force, is extensible, at least approximately 50% without experiencing a catastrophic failure. As used herein, the term "melt stabilized" refers to portions of a nonwoven web, which have been subjected to localized heating and / or localized pressure to substantially consolidate the fibers of the non-woven web to a form of stabilized film type.

BRIEF DESCRIPTION OF THE INVENTION In accordance with the present invention, a method for selectively piercing a non-woven web comprising the steps of: providing a non-woven web; attenuating the non-woven web in a plurality of locations to create a plurality of fused stabilized, attenuated locations; and applying a tensioning force to the non-woven web to cause the non-woven web to break into the plurality of melt stabilized, attenuated locations to create a plurality of apertures in the non-woven web coinciding with said fused stabilized, attenuated locations. The non-woven web may include carded, linked, spin-linked webs, or melt blown webs. Melt blown webs include microfibers blown in the molten state. The non-woven web may also have multiple layers such as, for example, multiple spin-bonded layers and / or multiple layers blown in the molten state. The non-woven material can be made of polymers such as for example polyolefins. Exemplary polyolefins include polyethylene, polypropylene, ethylene copolymers and propylene copolymers. The non-woven web may be an elastic non-woven web, an inelastic non-woven web or an expandable non-woven web.

BRIEF DISPLAY OF THE DRAWINGS Although the specification concludes with the claims pointing out in a particular way and claiming differently to the subject matter that is considered as formant of the present invention, it is believed that the invention will be better understood starting from the following description, which is taken in combination with the accompanying drawings in which similar designations are used to designate substantially identical elements, and in which: Figure 1 is a plan view of a disposable diaper embodiment of the present invention having portions cut away to reveal the structure Underlying, the inner surface of the diaper is facing the observer; Figure 2 is a schematic representation of an exemplary method for selectively punching a non-woven web of the present invention; Figure 3 is an enlarged perspective illustration of a frame attenuation arrangement of the present invention; Figure 4 is an enlarged, perspective illustration of an incremental stretching system of the present invention; Figure 5 is a schematic representation of another method for selectively punching a non-woven web of the present invention; Figure 6 is an enlarged perspective illustration of another array of frame attenuation of the present invention; Figure 7 is an enlarged, plan view photograph of a nonwoven web before being attenuated; Figure 8 is an enlarged plan view photograph of a non-woven web of the present invention after the non-woven web has been attenuated in a plurality of locations; and Figure 9 is an enlarged plan view photograph of a non-woven web of the present invention after tension has been applied to break the non-woven web at the attenuated locations to create openings in the non-woven web.

DETAILED DESCRIPTION OF THE INVENTION As used herein, the term "absorbent article" refers to devices that absorb and contain body exudates and, more specifically, refers to devices that are placed against or close to the user's body to absorb and contain the various discharged exudates. of the body. The term "disposable" is used herein to describe absorbent articles that are not intended to be washed or otherwise restored or reused, such as an absorbent article (ie, they are intended to be discarded after a single use, and preferably, to be recycled, composted or otherwise arranged in an environmentally compatible manner. A "unitary" absorbent article refers to absorbent articles that are formed of separate parts joined together, to form a coordinated entity such that they do not require separate manipulated parts such as a separate liner and fastener. A preferred embodiment of an absorbent article of the present invention is the unitary disposable absorbent article, diaper 20, shown in Figure 1. As used herein, the term "diaper" refers to an absorbent article generally worn by infants. and for babies and incontinent people around the user's lower torso. However, it should be understood that the present invention is also applicable to other absorbent articles such as incontinence briefs, incontinence undergarments, diaper liners and fasteners, feminine hygiene garments, training pants, and the like. Figure 1 is a plan view of the diaper 20 of the present invention in its flat state, without contracting (i.e., with the contraction induced by the elastic pulled out), with portions of the structure being cut out to show more clearly the construction of the diaper 20, and with the portion of the diaper 20 that faces the wearer, the interior surface 40, facing the viewer. As shown in Figure 1, the diaper 20 preferably comprises a containment assembly 22 comprising a top sheet 24 permeable to liquid; a liquid impermeable backsheet 26 attached to the topsheet; and an absorbent core 28 positioned between the topsheet 24 and the backsheet 26. The diaper preferably further comprises side elasticized panels 30; Elastic leg folds 32; elasticated waistbands 34; and a fastening system 36 preferably comprising a pair of securing members 37 and a landing member (not shown). The diaper 20 is shown in Figure 1 to have an inner surface 40 (facing the viewer in Figure 1), an outer surface 42 opposite the inner surface 40, a waist rear region 44, a waist front region 46 opposite the rear waist region 44, a crotch region 48 positioned between the rear waist region 44 and the waist front region 46, and a periphery that is defined by the outer perimeter or outer edges of the diaper 20, in which the longitudinal edges 50 are designated and the end edges 52 are designated. The inner surface 40 of the diaper 20 comprises that portion of the diaper 20 which is placed adjacent the wearer's body during use (i.e., the inner surface 40 is generally formed by at least a portion of the topsheet 24 and other components attached to the topsheet 24). The outer surface 42 comprises that portion of the diaper 20 that is positioned away from the wearer's body (i.e., the outer surface 42 is generally formed by at least a portion of the back sheet 26 and other components attached to the back sheet 26). As used herein, the term "attached" encompasses configurations with which one element is directly secured to the other element, fixing the element directly to the other element, and configurations with which the element is indirectly secured to the other element by fixing the element to a member or intermediate members, which in turn are fixed to the other element. The rear waist region 44 and the waist front region 46 extend from the end edges 52 of the periphery to the crotch region 48. The diaper 20 also has two centerlines, a longitudinal centerline 90 and a transverse center line 92. The term "longitudinal", as used herein, refers to a line, axis or direction in the plane of the diaper 20 that is generally aligned with (eg, approximately parallel to) a vertical plane that divides a user standing in left and right halves when diaper 20 is used. The terms "transverse", "lateral", as used herein, are interchangeable and refer to a line, axis or direction that lies within the diaper plane , which is generally perpendicular to the longitudinal direction (which divides the user) into front and back body halves). The containment assembly 22 of the diaper 20 is shown in Figure 1 as comprising the main portion (frame) of the diaper 20. The containment assembly 22 comprises at least the top sheet 24, the back sheet 26 and the absorbent core 28. When the absorbent article comprises a separate fastener and liner, the containment assembly 22 generally comprises the fastener and the liner (i.e., the containment assembly 22 comprises one or more layers of material to define the fastener while the liner comprises a material mixed absorbent such as a topsheet, a backsheet, and an absorbent core), for unitary absorbent articles, the containment assembly 22 comprises the diaper main structure with other features added to form the composite diaper structure. In this way, the containment assembly 22 for the diaper 20, generally comprises the topsheet 24, the backsheet 26, and the absorbent core 28. Figure 1 shows a preferred embodiment of the containment assembly 22 in which the top sheet 24 and the backsheet 26 have length and width dimensions generally greater than those of the absorbent core 28. The topsheet 24 and the backsheet 26 extend beyond the edges of the absorbent core 28 to thereby form the periphery of the diaper 20. Although the upper sheet 24, the upper back sheet 26 and the absorbent core 28 can be assembled in a variety of well-known configurations, exemplary containment assembly configurations are generally described in US Patent 3,860,003 entitled "Shrinkable side portions for disposable diaper", which was issued to Kenneth B. Buell on January 14, 1975; and U.S. Patent 5,151,092 entitled "Absorbent article with dynamic elastic waist feature having a predisposed elastic flexure joint", which was issued to Kenneth B. Buell et al. on September 29, 1992; each of which is incorporated herein by reference. The absorbent core 28 can be any absorbent member that is generally compressible, conformable, non-irritating to the wearer's skin and capable of absorbing and retaining liquids such as urine and other certain body exudates. As shown in Figure 1, the absorbent core 28 has a side facing the garment, a side facing the body, a pair of side edges, and a pair of waist edges. The absorbent core 28 can be manufactured in a wide variety of sizes and shapes (rectangular, hourglass), T-shaped, asymmetric, etc.), and from a wide variety of liquid absorbent materials commonly used in diapers disposable and other absorbent articles such as ground wood pulp, which is generally referred to as air felt. Examples of other suitable absorbent materials include creped cellulose wadding; melt blown polymers including coform; chemically modified or cross-linked cellulose fibers; tissue including tissue wraps and tissue laminates; absorbent foams, absorbent sponges; super absorbent polymers; gelling absorbent materials; or any equivalent material or combinations of materials. The configuration and construction of the absorbent core 28 can be varied, (e.g., the absorbent core can have variable gauge zones, a hydrophilic gradient, a superabsorbent gradient, or acquisition zones of lower average density and lower average basis weight, or may comprise one or more layers or structures). In addition, the size and absorbent capacity of the absorbent core can also be varied to suit users ranging from babies to adults. However, the total absorbent capacity of the absorbent core 28 must be compatible with the design load and intended use of the diaper 20. In one embodiment of the diaper 20 it has an asymmetric absorbent core 28, in the form of a modified T, having ears in the frontal region of the waist, but a generally rectangular shape in the posterior region of the waist. Exemplary absorbent structures for use as the absorbent core 28 of the present invention which have achieved wide acceptance and commercial success are described in U.S. Patent 4,610,678 entitled "High Density Absorbing Structures", issued to Weisman et al. On September 9 of 1986; U.S. Patent 4,673,402 entitled "Absorbent article with double layer cores", issued to Weisman et al. on June 16, 1987; U.S. Patent 4,888,231 entitled "Absorbent core having a dusting layer", issued to Angstadt on November 19, 1989; and U.S. Patent 4,834,735 entitled "High density absorbent members having lower basis weight acquisition and lower density zones", issued to Alemany et al. on May 30, 1989. The absorbent core may further comprise a system dual core containing a core of acquisition / distribution of chemically hardened fibers placed on the absorbent storage core as detailed in U.S. Patent 5,234,423, entitled "Absorbing article with characteristic elastic waist and increased absorbency", issued to Alemany et al. On August 10, 1993; and in U.S. Patent 5,147,345, entitled "High Efficiency Absorbent Articles for Managing Incontinence," issued to Young La Von and Taylor on September 15, 1992. All of these patents are incorporated herein by reference. . The backsheet 26 is positioned adjacent to the garment facing surface of the absorbent core 28, and is preferably attached to it by fixing means (not shown) such as those well known in the art, for example, the backsheet 26 can be secured to the absorbent core 28 by a continuous, uniform adhesive layer, a layer of adhesive with pattern, or an arrangement of lines, spirals or separate adhesive spots. The adhesives that have been found to be satisfactory are manufactured by H.B. Fuller Company of St. Paul, Minnesota and are marketed as HL.1258. An example of a suitable fixing means comprising an open-pattern network of filaments of adhesives is disclosed in U.S. Patent 4,573,986, entitled "Disposable Waste Containment Garment," which was issued to Minetola et al. March 1986. Other suitable fixation means comprising several lines of adhesive filaments twisted in a spiral pattern are illustrated by the apparatus and methods shown in US Pat. No. 3,911,173 issued to Sprague.; jr.

On October 7, 1975; U.S. Patent 4,785,996 issued to Ziecker et al. on November 22, 1978; and U.S. Patent 4,842,666 issued to Werenicz on June 27, 1989. Each of these patents is incorporated herein by reference. Alternatively, the fixation means may comprise heat bonds, pressure bonds, ultrasonic bonds, mechanical dynamic links or any other suitable means of attachment or combination of these fixation means as are known in the art. Also contemplated are embodiments of the present invention where the core is not attached to the back sheet 26, the back sheet 24 or both in order to provide greater extension capacity in the front waist region 46 and in the posterior waist region 44. The backsheet 26 is impervious to liquids (eg urine), and is preferably manufactured from a thin plastic film, although other flexible liquid impervious materials may also be used. As used herein, the term "flexible" refers to materials that are docile and readily conform to the shape and general contour of the human body. The backsheet 26 prevents the exudates absorbed and contained within the absorbent core 28 from wetting the articles that come into contact with the diaper 20 such as sheets and undergarments, however, the backsheet 26 may allow the vapors to escape from the core. absorbent 28 (ie, it is breathable). In this manner, the backsheet 26 preferably comprises a polymeric film such as polyethylene or polypropylene thermoplastic films. A suitable material for backsheet 26 is a thermoplastic film having a thickness of from about 0.012 mm to about 0.051 mm. The topsheet 24 is positioned adjacent the surface facing the body of the absorbent core 28 and is preferably attached to it and to the backsheet 26 by attachment means (not shown) such as those well known in the art. Suitable attachment means are described with respect to the attachment of the backsheet 26 to the absorbent core 28. In a preferred embodiment of the present invention, the topsheet 24 and the backsheet 26 are directly bonded together at the periphery of the diaper and they are indirectly joined together by attaching them directly to the absorbent core 28 by the fixing means (not shown). The topsheet 24 is preferably docile to feel soft and non-irritating to the user's skin. In addition, the topsheet 24 is preferably liquid permeable allowing liquids (eg, urine) to easily penetrate through its thickness. A suitable top sheet 24 is manufactured from a non-woven web of synthetic fibers, (e.g., polyester, polyethylene or polypropylene fibers or bicomponent fibers).

Other suitable fibers include natural fibers such as wood, cotton or rayon fibers or combinations of natural and synthetic fibers. The topsheet 24 of the present invention preferably comprises a nonwoven web with openings. Referring to Figure 2 there is schematically illustrated at 100 a method for selectively punching a nonwoven web suitable for use as a top sheet in a disposable absorbent article. In accordance with the present invention, a non-woven web 102 is wound from a supply roll 104 and travels in a direction indicated by the arrows associated therewith, as the supply roll 104 rotates in the direction indicated by the arrows associated with it. The non-woven material 102 passes through a contact point 106 of the arrangement of the attenuating roller of the weft 108 formed by the rollers 110 and 112. The non-woven material 102 can be formed through non-woven weft extrusion processes. known, such as, for example, well known meltblown processes or well known spin bonding processes, and passes directly through the contact point 106 without first being linked and / or stored on a supply roll. The nonwoven web 102 may be extensible, elastic or non-elastic. The non-woven web 102 may be a spin-linked web, a web blown under melt, or a bonded carded web. If the nonwoven web is a web of blown fibers under melting, this may include microfibers blown under melting. The non-woven web 22 can be made of forming polymer fibers such as, for example, polyolefins. Exemplary polyolefins include one or more of copolymers of polypropylene, polyethylene, ethylene, propylene copolymers, and butene copolymers. In another embodiment, the nonwoven web 102 may be a multi-layer material having, for example, at least one layer of a web spun by at least one layer or a meltblown web, a bonded webbed web , or other suitable material. For example, the nonwoven web 102 may be a multilayer web having a first spunbonded polypropylene layer having a basis weight of from about 0.2 to about 8 ounces per square yard, a meltblown polypropylene layer that have a basis weight of from about 0.2 to about 4 ounces per square yard, and a second layer of spin-jointed polypropylene having a basis weight of from about 0.2 to about 8 ounces per square yard. Alternatively, the non-woven web can be a single layer or material, such as, for example, a spin-linked web having a basis weight of about 0.2 to about 10 ounces per square yard, or a melt blown web that it has a basis weight of about 0.2 to about 8 ounces per square yard. The nonwoven web can be joined to a polymeric film to form a laminar unit. Suitable polymeric film materials include but are not limited to polyolefins, such as copolymers of polyethylene, polypropylene, ethylene, propylene copolymers, and butene copolymers; nylon (polyamide); polymers based on metallocene catalyst; cellulose esters; poly (methyl methacrylate); polystyrene; polyvinylchloride); polyester; polyurethane; compatible polymers; compatible copolymers; and mixtures; laminar units and / or combinations thereof. The nonwoven web 102 can also be a composite made from a mixture of two or more different fibers or a mixture of fibers and particles. Said mixtures can be formed by adding the fibers and / or particles to the gas stream where the meltblown fibers or the spunbonded fibers are carried, whereby a tangled co-mix of fibers and other materials, eg pulp, is produced. of wood, staple fibers and particles, occurs before the fibers are harvested. The non-woven web of fibers must be bonded together to form a coherent web structure. Suitable bonding techniques include, but are not limited to, chemical bonding, thermobonding, such as point calendering, hydroentangling and needleworking.

Referring now to Figure 7, there is shown a photograph of a coherent nonwoven web 102 before entering the contact point 106. As can be seen from Figure 7, the coherent nonwoven web comprises a plurality of fibers joined together by knitted calendered joints 200 to form a coherent weft structure. Referring now to Figures 2 and 3, the weft attenuation roller 108 preferably comprises a patterned calender roll 110 and a smooth anvil roller 112. One or both the pattern 110 calender roll and the platen roll 110. smooth anvil 112 can be heated and the pressure between the two rolls can be adjusted through well-known means to provide the temperature, if any, and pressure desired to concurrently attenuate and stabilize under melt the non-woven web 102 in a plurality of locations The pattern calendering roller 110 is configured to have a circular cylindrical surface 114, and a plurality of protrusions or pattern elements 116, which extend outwardly from the surface 114. The protuberances 116 are arranged in a predetermined pattern with each boss 116 being configured and arranged to precipitate an attenuated location, stabilized under melting, in the nonwoven web 102 to effect a predetermined pattern of attenuated locations, stabilized under melting, in the non-woven web 102. As shown in Figure 3, the pattern calendering roller 110 has a pattern of repeating protrusions 116, which extend around the entire circumference of the surface 114. Alternatively, the protuberances 116 may extend around a portion, or portions or circumference of the surface 114. The protuberances 116 are preferably truncated conical shapes , which extend radially outwardly from the surface 114 and which have distant and elliptical end surfaces 117. While not intended to limit the scope of the present invention to protrusions of only this configuration. Other suitable shapes for the distal ends 117 include, but are not limited to, circular, square, rectangular, etc. The roller 110 is finished so that all the end surfaces 117 lie in an imaginary right circular cylinder, which is coaxial with respect to the axis of rotation of the roller 110. The protuberances 116 are arranged in a regular predetermined pattern of rows and columns in the embodiment shown in Figure 3, although it is not intended to limit the scope of the present invention to the protuberance pattern of only this configuration. The protuberances may be arranged in any predetermined pattern around the pattern calendering roll 110. The anvil roll 112 is preferably a straight, smooth circular steel cylinder. Figure 8 is a photograph of the nonwoven web 102 after it has passed through the attenuation roll arrangement 108, and before passing through the contact point 130 of the incremental stretching system 132. As can be seen in FIG. In the photograph, the non-woven web 102 includes a plurality of attenuated locations, stabilized under melting 202. The attenuated, melt-stabilized locations 202 generally correspond to the pattern of protuberances 116 extending from the surface 114 of the pattern 110 calender roller. In Figure 8, the nonwoven web 102 also includes a coherent web forming calendered point junctions 200, which serve to maintain the structural integrity of the non-woven web 102. From the dimmer roller arrangement 108, the non-woven web 102 passes through contact point 130 formed by incremental stretch system 132 using applicators of opposite pressure that have three-dimensional surfaces, which, at least to a degree, are complementary to each other. Referring now to Figure 4, a fragmentary enlarged view of the incremental stretching system 132, comprising incremental stretching rollers 134 and 136, is shown. The incremental stretching roller 134 includes a plurality of teeth 160 and corresponding grooves 161, which they extend around the entire circumference of the roller 134. The incremental stretching roller 136 includes a plurality of teeth 162 and a plurality of corresponding grooves 163. The teeth 160 on the roller 134 mesh with or engage the slots 163 on the roller 136, while the teeth 160 on the roller 134 engage with or engage the slots 161 on the roller 134. As the non-woven web 102, which has attenuated locations, stabilized under melting 202, passes through the incremental stretching system 132, the nonwoven web 22 is subjected to an incremental stretch or tension in the CD or transverse direction to the machine, causing the non-woven web 102 to be extended in the CD direction. Alternatively or additionally, the non-woven web 102 may be tensioned in the MD or machine direction. The tensile force placed on the non-woven web 02 is adjusted, so as to cause the attenuated, melt-stabilized locations 22 to break, creating a plurality of apertures 204 coinciding with the attenuated locations, stabilized under melting 202 in the weft. woven 102. However, the joints of the nonwoven web 102 are preferably strong enough, so that they do not break during tension, thus maintaining the non-woven web in a coherent condition although the attenuated locations stabilized under melting break. However, it may be desirable for some of the joints to break during tension. Referring now to Figure 9, a photograph of the non-woven web 102 is shown after being subjected to the tension force applied by the incremental stretching system 132. As can be seen in the photograph, the non-woven web 102 now includes a plurality of openings 204, which are coincident with the attenuated, stabilized locations under melting 202 of the non-woven fabric shown in Figure 8. A portion of the circumferential edges of the openings 204 comprises remnants 205 of the stabilized locations under Fusion 202. It is believed that the remnants 205 help to further resist tearing of the non-woven web, particularly when the non-woven web is used as a topsheet in a disposable absorbent article. Other illustrative structures of incremental stretching mechanism including incremental stretching rollers suitable for increasing stretching of the nonwoven web are described in International Patent Publication No. WO 95/03765, published on February 9, 1995, in the name of Chappell. and others., the description of which is incorporated herein by reference. The selectively perforated nonwoven web can also be used as a top sheet in other disposable absorbent articles such as, for example, incontinence briefs, training pants, feminine hygiene garments and the like. The non-woven web with openings in other parts of a disposable absorbent article such as, for example, an acquisition layer placed between the topsheet and the absorbent core, as part of the absorbent core, or as parts of other absorbent components may also be used. Disposable absorbent article. The nonwoven web 102 is preferably taken on a winding roller 180 and it is stored. Alternatively, the non-woven web 102 can be fed directly to a production line, where it is used to form a topsheet on a disposable absorbent article. Referring to Figure 5, there is schematically illustrated in 300 another process for selectively piercing a nonwoven web of the present invention. A nonwoven web 302 is wound from a supply roll 304 and travels in a direction indicated by the arrows associated therewith, as the supply roll 304 rotates in the direction indicated by the arrows associated therewith. The non-woven material 302 is sent through the weft attenuation arrangement 308. The non-woven material 102 can be formed through known extrusion processes, such as, for example, known melt blowing processes or bonding methods. by known spinning, and passes directly through the weft attenuation arrangement 308. The non-woven weft 302 may be extensible, elastic or non-elastic. The non-woven web 302 may be a spin-linked web, a melt blown web, or a bonded carded web. If the nonwoven web is a web of blown fibers under melting, this may include microfibers blown under melting. The nonwoven web 302 may be made of forming polymer fibers such as, for example, polyolefins. Exemplary polyolefins include one or more of copolymers of polypropylene, polyethylene, ethylene, propylene copolymers, and butene copolymers. In another embodiment, the nonwoven web 302 may be a multi-layer material having, for example, at least one layer of a web spunbonded to at least one layer or a meltblown web, a bonded webbed web , or other suitable material. The nonwoven web can be joined to a polymeric film to form a laminar unit. Suitable polymeric film materials include but are not limited to polyolefins, such as copolymers of polyethylene, polypropylene, ethylene, propylene copolymers, and butene copolymers; nylon (polyamide); polymers based on metallocene catalyst; cellulose esters; poly (methyl methacrylate); polystyrene; polyvinylchloride); polyester; polyurethane; compatible polymers; compatible copolymers; and mixtures; laminar units and / or combinations thereof. The non-woven web 302 may also be a composite made from a mixture of two or more different fibers or a mixture of fibers and particles. Said mixtures can be formed by adding the fibers and / or particles to the gas stream where the meltblown fibers or the spunbonded fibers are carried, whereby a tangled co-mix of fibers and other materials, eg pulp, is produced. of wood, staple fibers and particles, occurs before the fibers are harvested. The non-woven web of fibers must be bonded together to form a coherent web structure. Suitable bonding techniques include, but are not limited to, chemical bonding, thermobonding, such as point calendering, hydroentanglement and needling. Referring now to Figures 5 and 6, a frame attenuation arrangement 308 is shown preferably comprising an ultrasonic transducer 306 and a cylinder 310. As the non-woven web 302 advances between the ultrasonic transducer 306 and the anvil cylinder 310 , the non-woven web 302 is subjected to an ultrasonic vibration energy, whereby the predetermined pattern locations of the non-woven web 302 are attenuated and stabilized under melting. The anvil 310 has a multitude of discrete pattern protuberances, which are generally designated 316, disposed on its surface 314 that faces outward in a predetermined pattern, which extends around the entire circumference of the anvil cylinder. The protuberances 316 are arranged in a predetermined pattern with each protrusion 316 being configured and arranged to precipitate an attenuated location, stabilized under melting 304 in the non-woven web 302 to effect a predetermined pattern of attenuated locations, stabilized under melting in the non-woven web 302. As shown in Figure 6, the anvil 310 has a bump repeat pattern 316, which extends around the entire circumference of the surface 314. Alternatively, the bumps 316 may extend around a portion, or portions thereof, of the protrusion 316. circumference of the surface 314. The protuberances 316 are preferably truncated conical shapes, which extend radially outward from the surface 314 and which have distant and elliptical end surfaces. Other suitable shapes for the distant ends include, but are not limited to, circular, square, rectangular, etc. The anvil 310 is terminated so that all the end surfaces lie in an imaginary right circular cylinder, which is coaxial with respect to the axis of rotation of the anvil 110. After having passed through the attenuation roller arrangement 308, and before passing through the contact point 330 of the incremental stretching system 332, the non-woven web 302 includes a plurality of fused attenuated locations 304, which generally correspond to the pattern of protrusions 316 extending from the surface 314 of the anvil 310. From the attenuation arrangement 308, the non-woven web 102 passes through the space 330 formed by the incremental stretching system 332 using opposing pressure applicators having three-dimensional surfaces, which at least up to a certain degree are complementary to each other. The incremental stretching system 332 preferably comprises incremental stretching rolls 334 and 336. The incremental stretching thread 334 includes a plurality of corresponding teeth and grooves which extend around the total circumference of the roller 334. The incremental drawing roller 336 includes a plurality of teeth and a plurality of corresponding grooves. The teeth on the roller 334 mesh with the groove on the roller 136, while the teeth on the roller 336 mesh with or engage with the groove toward the roller 334. As the non-woven web 302 having stabilized locations under fused, attenuated 304 passes through the incremental stretching system 332, the non-woven web is subjected to tensioning causing the web to be stretched. The tensioning force placed on the nonwoven web is adjusted such that it causes the melt stabilized, attenuated locations 304 to break creating a plurality of openings in the nonwoven web which are coincident with the fused stabilized, attenuated locations. The nonwoven web 302 is preferably formed on a winding roller 380 and stored. Alternatively, the non-woven web 302 can be fed directly to a production line where it is used to form a topsheet in a disposable absorbent article. The diaper 20 preferably further comprises elasticized leg folds 32 to provide improved containment of liquids and other exudates from the body. Each elasticized leg cuff 32 may comprise several different embodiments to reduce leakage of body exudates in the leg regions. (The leg fold can be and is sometimes also referred to as leg bands, side flaps, barrier folds or elastic folds.) The United States Patent 3,860,003 discloses a disposable diaper that provides a collapsible leg opening having a side flap and one or more elastic members to provide an elasticized leg fold (packing fold). The United States Patent 4, 909,803 entitled "Disposable absorbent article having elasticized fins", issued to Aziz et al. On March 20, 1990, discloses a disposable diaper having "upright" elasticized folds (barrier folds), to improve containment of the regions of Leg US Patent 4,695,278 entitled "Absorbent Article Having Double Folds", issued to Lawson on September 22, 1987, describes a disposable diaper having double folds that includes a gusset fold and a barrier fold. U.S. Patent 4,704,115 entitled "Disposable Waste Containment Garment", issued to Buell on November 3, 1987, discloses a disposable diaper or incontinence garment having sidewall leakage channels configured to contain the free liquids within of the garment Each of these patents is incorporated herein by reference, since each elasticized leg 32 fold can configu In order to be similar to any of the leg bands, side flaps, barrier folds or elastic folds described above, it is preferred that each leg elastified fold 32 comprises at least one internal barrier fold comprising a barrier flap and a spacer element as described in the aforementioned US Pat. No. 4,909,803. In a preferred embodiment, the elasticized leg fold 32 further comprises a resilient gusset of packing with one or more elastic threads, placed outside the center of the barrier fold as described in the aforementioned US Pat. No. 4,695,278. The diaper 20 further preferably comprises an elasticated waistband 34, which provides improved fit and containment. The elastic waistband 34 is that portion or area of the diaper 20 which is intended to expand and contract elastically, to dynamically adjust the wearer's waist. The elasticized waistband 34 preferably extends longitudinally outwardly from at least one of the waist edges of the absorbent core 28, and generally forms at least a portion of the end edge of the diaper 20. Disposable diapers are generally constructed to have two waistbands elasticized, one placed in the posterior region of the waist and one placed in the front waist region, although you can build diapers with a single elasticated waistband. Further, since the elasticized waistband 34 or any of its constituent elements may comprise a separate element secured to the diaper 20, the elasticized waistband 34 may be constructed as an extension of other diaper elements, such as the backsheet 26 or the upper sheet 24 , preferably, both the backsheet 26 and the top sheet 24. The elasticized waistband 34 can be constructed in a number of different configurations including those described in U.S. Patent 4,515,595, entitled "Disposable diapers with elastically shrinkable waistbands", issued to Kievit et al. On May 7, 1985, and the aforementioned United States Patent 5,151,092 issued to Buell, each of these patents being incorporated herein by reference. In a preferred embodiment, the diaper 20 also comprises side elasticized panels 30 disposed in the rear waist region 44. (As used herein, the term "disposed" is used to imply that a diaper element or elements is formed (attached and placed) in a particular location or position as a unitary structure with the other elements of the diaper or as a separate element attached to another diaper element). The side elasticized panels 30 provide an elastically extensible feature that provides greater comfort and contour adjustment by initially comfortable fitting the diaper 20 to the wearer and holding this fit throughout the time of use, much later when the diaper has been loaded with exudates since the elasticized side panels will allow the nappy diapers to expand and contract. The side elasticized panels 30 further provide a more effective application of the diaper 20, since even if the diaper user pulls an elasticized panel 30 farther than the other during asymmetric application), the diaper 20 will self-adjust during use . Since the diaper 20 of the present invention preferably has side elasticized panels 30 arranged in the rear waist region 44; alternatively, the diaper 20 can also be provided with lateral elasticized panels in the waist front region 46 and in the waist rear region 44. As the side elasticized panels 30 can be constructed in a number of configurations, examples of diapers with panels Lateral elastics are disclosed in U.S. Patent 4,857,067 entitled "Disposable diaper having grip ears", issued to Wood et al. on August 15, 1989; U.S. Patent 4,381, 781, issued to Sciaraffa et al. on May 3, 1983; U.S. Patent 4,938,753, issued to Van Gompel et al. on July 3, 1990; and in U.S. Patent 5,151,092, issued to Buell et al. on September 29, 1992; each of which is incorporated herein by reference. Elastic materials suitable for use as the side elasticized panels include elastomeric foams, synthetic or natural rubber, synthetic or natural rubber foam, elastomeric films, elastomeric canvases, non-woven or elastomeric woven fabrics, elastomeric composite materials such as elastomeric non-woven laminates, or similar. The diaper 20 also comprises a fastener system 36 that forms a side closure, which maintains the waist rear region 44 and the waist front region 46 in an overlapping configuration such that side tensions if maintained around the circumference of the diaper , to keep the diaper on the user. Illustrative fastening systems are disclosed in U.S. Patent 4,869,724 issued to Scripps on September 26, 1989; U.S. Patent 4,846,815 issued to Scripps on July 11, 1989; U.S. Patent 4,894,060 issued to Nestegard on January 16, 1990 U.S. Patent 4,946,527 issued to Battrell on August 7, 1990; U.S. Patent 3,848,594, issued to Buell on November 19, 1974; and U.S. Patent 4,66,875 issued to Hirotsu and Robertson on May 5, 1987. Each of these patents is incorporated herein by reference. Since particular embodiments of the present invention have been illustrated and described, it would be obvious to those skilled in the art that various other changes and modifications can be made without departing from the spirit and scope of the invention. It is therefore intended to protect in the appended claims all of these changes and modifications that are within the scope of the present invention.

Claims (10)

1. - A method for selectively perforating a nonwoven web characterized by the steps of: (a) attenuating the nonwoven web at a plurality of locations to create a plurality of fused stabilized, attenuated locations; and (b) applying a tension force to said non-woven web to cause the non-woven web to break into the plurality of fused stabilized, attenuated locations, creating a plurality of openings in the non-woven web, coinciding with the plurality of locations stabilized under melting, attenuated.

2. The method according to claim 1, wherein the nonwoven web is a web selected from the group consisting of a woven web of woven fibers, a web of spin-bonded fibers, a web of blown fibers under melting, and a multi-layer material that includes at least one of said frames.

3. The method according to claim 2, wherein the fibers comprise a polymer selected from the group consisting of polyolefins, polyesters and polyamides.

4. The method according to claim 1, wherein the nonwoven web is a composite material comprising a mixture of fibers and one or more other materials selected from the group consisting of wood pulp, short fibers, particles and materials superabsorbents

5. The method according to claim 1, wherein the non-woven web is a web selected from the group consisting of an elastic non-woven web, a non-woven non-woven web, and an expandable non-woven web.

6. A nonwoven web characterized by a plurality of openings formed by the application of a tension force, said openings coinciding with a plurality of locations stabilized under fusion, attenuated, the openings having a circumferential edge, a part of said circumferential edge being defined by a remnant of the stabilized locations under fusion.

7. The non-woven web according to claim 6, wherein the non-woven web forms a top web in a disposable absorbent article.

8. The non-woven web according to claim 6, wherein the non-woven web is a web selected from the group consisting of a web of bonded carded fibers, a web of spin-bonded fibers, a web of low-blown fibers fusion and multi-layer material that includes at least one of said frames.

9. The nonwoven web according to claim 6, wherein the fibers comprise a polymer selected from the group consisting of polyolefins, polyesters and polyamides.

10. The nonwoven web according to claim 6, wherein the non-woven web is a composite material comprising a mixture of fibers and one or more other materials selected from the group consisting of wood pulp, short fibers, particles and superabsorbent materials. The non-woven web according to claim 6, wherein the non-woven web is a web selected from the group consisting of an elastic non-woven web, an inelastic non-woven web, and an expandable non-woven web. 12. An apparatus for selectively perforating a nonwoven web characterized by: (a) means for attenuating the nonwoven web at a plurality of locations to create a plurality of fused, attenuated stabilized locations, and (b) means for applying a tensile force to said non-woven web to break the non-woven web into the plurality of melt-stabilized, attenuated locations, creating a plurality of openings in the non-woven web that coincide with the plurality of melt-stabilized, attenuated locations.