MXPA01002290A - Strong and soft apertured nonwoven web - Google Patents

Abstract

A nonwoven web which may be used as a topsheet on a disposable absorbent article, such as a diaper. The nonwoven web has a central zone and two outer zones each having a bonded area. The bonded area of the outer zones being greater than the bonded area of the central zone to provide a soft central zone and strong outer zones.

Description

NON-WOVEN FRAME WITH RESISTANT AND SOFT OPENINGS FIELD OF THE INVENTION This invention relates to a nonwoven web with tough and soft openings, and more particularly to a tough and soft nonwoven web suitable for use as a top sheet in a disposable absorbent article.

BACKGROUND OF THE INVENTION Disposable absorbent articles such as diapers and adult incontinence products are well known in the art. These disposable absorbent articles collect and retain urine and fecal material deposited thereon by the user. Disposable absorbent articles typically comprise a liquid-permeable topsheet which faces toward and is in contact with the wearer's body, a backsheet impervious to liquid attached to the topsheet, and an absorbent core positioned between the topsheet and the backsheet. back sheet. Since the top sheet comes into contact with the user's body it is preferably of a soft, non-irritating feel to the wearer's skin. However, the top sheet must have the required strength to maintain its integrity during use and manufacture. With the thermally bonded non-woven webs, the amount of bound area of the web is a factor in determining both of the softness / strength of the web. According to e! The united area of the weft increases, the softness decreases and the resistance to tension increases. In contrast, as the area of the weft decreases, the softness increases and the tensile strength decreases. In past attempts, a J * ^ AA ^ -A - - * - "- = - - ^^ - ^ - - - ^« «^ a- ^ bound area was selected for the total non-woven plot which was an accommodation between the properties of softness and strength Although acceptable, the softness and strength properties provided were not the most preferred since each had to be sacrificed or compromised in order to provide an acceptable top sheet.5 It has been found that it is not necessary to provide the total top sheet of the diaper with such high strength as high smoothness In fact, the central portion of the upper sheet which is typically placed between the barrier cuffs for the diaper leg, is the portion that is in contact with the wearer's body and Such a way needs to be smooth, however, the central portion is not subject to much effort during use and / or manufacture and does not need to be resistant in relation to the outer portions. The outer portions are the portions of the upper sheet that are placed outward from the leg barrier folds. These portions of the topsheet typically have relatively little contact with the wearer's skin depending on the particular design of diaper v so that they do not need to be so - soft as the central portion. However, the outer portions are subjected to higher stresses during use and / or manufacture and therefore need to be relatively resistant as compared to the central portion.

BRIEF DESCRIPTION OF THE INVENTION The invention is a nonwoven web which can be used as a topsheet in a disposable absorbent article, such as a diaper. The nonwoven web comprises a first or central zone and at least one second or external zone each having a joined area. Preferably, the frame comprises a central zone and a pair of external zones. The united area of said external zones being greater than the united area of the central zone. The central zone has an effective open area of at least ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ amp; ^^^^^^^^^^^^^^^^^ * ^^^^^^^ a - - * approximately 10 percent and a plurality of openings with an effective size of at least 0.2 square millimeters . In other embodiments, the outer zone may have an effective open area of at least about 10 percent and a plurality of openings with an effective size of at least 0.2 square centimeters.

BRIEF DESCRIPTION OF THE DRAWINGS Although the description concludes with the claims singling out and claiming the present invention differently, it is believed that it will be better understood by the following drawings taken in combination with It is a description that accompanies where similar components are given with the same reference number. Figure 1 is a plan view illustration, shown partially in section, of a disposable diaper having a top sheet constructed of the frame of the invention. I presented. Figure 2 is a simplified schematic illustration of a process for forming the nonwoven web of the present invention. Figure 3 is an enlarged plan view illustration on top of the joining apparatus of Figure 2. Figure 4 is an enlarged top-view illustration of the perforating apparatus of Figure 2. Figure 5 is a simplified schematic illustration of an alternative process for forming the nonwoven web of the present invention. Figure 6 is an enlarged plan view illustration on top of the attachment apparatus of Figure 5.

DETAILED DESCRIPTION OF THE INVENTION As used herein, the term "absorbent article" refers to devices that absorb and contain exudates from the body, and, more specifically, refers to devices that are placed against or close to the user's body to absorb and contain the various exudates discharged from the body. The term "disposable" is used herein to describe absorbent articles that are not intended to be washed or restored or reused in another way as an absorbent article (ie, they are intended to be discarded after a single use and , preferably, to be recycled, composted or otherwise disposed of 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 separate manipulated parts are not required as a separate support and liner. An absorbent article that uses the weft of the present invention as a topsheet thereon is the disposable, unitary absorbent article, diaper 20, shown in Figure 1. As used herein, the term "diaper" refers to an article Absorbent generally worn by incontinent babies and adults and is carried around the user's lower torso. The weft of the present invention may also be used as a topsheet in other absorbent articles such as incontinence briefs, incontinence undergarments, absorbent inserts, and diaper liners, feminine hygiene garments, and the like. Although the present invention will be described in the context of providing a weft suitable for use as a topsheet on a disposable absorbent article, the present invention is by no means limited to such an application.

The description of the frame and its use as a top sheet will enable one skilled in the art to easily adapt the invention to other devices and for other uses. Figure 1 is a plan view of the diaper 20 of the present invention in its flattened state, without contracting (i.e., with the elastic-induced contraction pulled outward) with portions of the structure that are trimmed to more clearly show the construction of the diaper 20 and with the portion of the diaper 20 that faces toward or is in contact with the wearer, the inner surface, facing the viewer. As shown in Figure 1, the diaper 20 preferably comprises a liquid-permeable topsheet 24, a liquid-impermeable backsheet 26 bonded to the topsheet 24; and an absorbent core 28 intermediate to the topsheet 24 and the backsheet 26. AND? diaper 20 may further comprise elasticized side panels (not shown); elastic folds for the leg (not shown); and an elastic waist feature (not shown): and a fastening system with generally multiple tape tabs designated 36. • The diaper 20 is shown in Figure 1 to have a first waist region 27 juxtaposed with the front of the waistband. user while the diaper 20 is worn, a second waist region 29 opposite the first waist region 27 and juxtaposed with the back of the wearer while the diaper 20 is being worn, a crotch region 31 positioned between the first region of waist 27 and second waist region 29, and a periphery that is defined by the outer edges of! diaper 20 in which the longitudinal edges are designated 33 and the end edges are designated. The inner surface of the diaper 20 comprises that portion of the diaper 20 that is adjacent to the user's body during use (i.e., the inner surface is generally formed by at least a portion of the topsheet 24 and other components attached to the topsheet 24). The outer surface comprises that portion of the diaper 20 that is positioned away from the wearer's body (i.e., the outer surface is formed by ^ gj ^., ^ .. ^ jg. general by at least a portion of the backsheet 26 and other components attached to the backsheet 26) during use. Figure 1 shows a modality of the diaper 20 in which the topsheet 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 topsheet 24, the backsheet 26, and the absorbent core 28 can be assembled in a variety of well-known configurations, the configurations are generally described. preferred diaper in the patent of the United States No. 3,860,003 entitled "Shrinkable side portions for disposable diaper" which was issued to Kenneth B. Buell on January 14, 1975; and in United States Patent No. 5,151, 092, 'Absorbent Article with Elastic Dynamic Waist Characteristic Having a Restrained Flexure Joint Biased, "issued to Kenneth B. Buell on September 29, 1992; which is incorporated here by reference. AND! Absorbent core 28 can be any absorbent means that is generally compressible, capable of shaping, non-irritating to the wearer's skin, and capable of absorbing and retaining liquids such as urine and other certain exudates from the body. As shown in Figure 1, the absorbent core 28 has a garment surface, a body surface, side edges, and waist edges. The absorbent core 28 can be manufactured in a wide variety of sizes and shapes (eg, rectangular, hourglass, T-shaped, asymmetric, etc.) and from a wide variety of liquid absorbent materials commonly used in disposable diapers and other absorbent articles such as pulp of crushed wood which is generally referred to as air felt. Examples of other suitable absorbent materials include acrylic cellulose wadding, meltblown polymers ta including coform; cellulose fibers, chemically hardened, modified or interlaced; tissue including tissue wraps and tissue laminates; absorbent foams; absorbent sponges; superabsorbent polymers; gelling absorbent materials; or any equivalent or combinations of materials. The configuration and construction of the absorbent core 28 can also be varied (eg, the absorbent core 28 can have varying gauge zones, a hydrophilic gradient, a superabsorbent gradient, or acquisition zones with lower average density and lower average basis weight; may comprise one or more layers or structures). 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 addition, the size and absorbent capacity of the absorbent core 28 can be varied to encompass users ranging from babies to adults. Illustrative absorbent structures for use as the absorbent core 28 are described in United States Patent No. 4,610,678 entitled "High Density Absorbing Structures" issued to Weisman et al. On September 9, 1986; U.S. Patent No. 4,673,402 entitled "Absorbent articles with cores in double layers" 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; and in U.S. Patent No. 4,834,735 entitled "High density absorbent members having acquisition zones with lower density and lower basis weight" issued to Aleman and others on May 30, 1989. Each of these patents is incorporated herein. by reference. The backsheet 26 is positioned adjacent the garment surface of the absorbent core 28 and is preferably attached thereto by means of fixation (not shown) such as those well known in the art. As used here, the term a ^^^^^^^^^ fe ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ element to the other element by fixing the element directly to the other element, and configurations by 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. For example, backsheet 26 can be secured to the absorbent core 28 by a continuous uniform adhesive layer, a patterned adhesive layer, an array of separate lines, spiers, or spots of adhesive. The adhesives that have been found to be satisfactory are manufactured by H.B. Fuller Company of St. Paul, Minnesota and marketed as HL-1258. The fastening means will preferably comprise a network of open-pattern adhesive filaments as disclosed in U.S. Patent No. 4,573,986 entitled "Disposable garment for containment of waste" which was issued by Mipetola et al. On March 4, 1986 , more preferably several lines of adhesive filaments twisted in a pattern in this case! as illustrated by the apparatus and methods shown in United States Patent No. 3,911, 173 issued to Sprague, Jr. on October 7, 1975; U.S. Patent No. 4,785,996 issued to Ziecker, and others on November 22, 1978; and in U.S. Patent No. 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 joints, ultrasonic joints, mechanical dynamic joints, or any other suitable means of attachment or combinations of these fixation means as are known in the art. The backsheet 26 is impermeable 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 here, the - ~ » -Aa &* £ * sx. , J, «- -« < .-? áßtS ^ ¿StfJ ^^ m »Aea» ^ t & ß ^ i ^ »^ Íi ?? ks ^? ^.« ». - *** & ^ ~? M * aaXh¿Í¡í &amp -? =.

The term "flexible" refers to materials that are flexible and that will easily conform to the figure and general outline of the human body. The backsheet 26 prevents the exudates absorbed and contained within the absorbent core 28 from wetting the articles that are in contact with the diaper 20, such as sheets and undergarments. The backsheet 26 may therefore comprise a woven or non-woven material, polymeric films such as polyethylene or polypropylene thermoplastic films, or composite materials such as a film-coated nonwoven material. Preferably, the backsheet 26 is a thermoplastic film having a thickness of about 0.012 m to about 0.051 mm. The Particularly preferred materials for the backsheet 26 include the RR8220 blown films and the RR5475 cast films as manufactured by Tredegar Industries, Inc. of Terre Haute, Indiana. The backsheet 26 is preferably finished in highlight and / or dull to provide a more fabric-like appearance. In addition, backsheet 26 can allow core vapors to escape absorbent 28 (ie, be breathable) while still preventing exudates from passing through the backsheet 26. The topsheet 24 is juxtaposed with, but not necessarily adjacent to the body surface of the absorbent core 28, and is preferably attached to the backsheet 26 or to the absorbent core 28 by means such as those well known in the art. Suitable attachment means are described above 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. The upper sheet 24 comprises a non-woven web 40 permeable to the liquid. The frame 40 comprises a first or central zone 70 and at least a secondary or external zone 72. Preferably, the frame 40 comprises a central area 70 and a pair of external zones 72. The central area 70 will be placed generally between the diaper leg barrier folds and is the portion of the top sheet that is in contact with the wearer's body. Therefore, the central zone 70 needs to be smooth. Although the central zone needs to be soft it is not subjected to relatively high stresses during use and / or manufacture, and thus does not need to be resilient in relation to the outer zones 72. The outer zones 72 are the portions of the sheet The upper ones are going to be placed generally outside the leg barrier folds. These portions of the upper sheet typically do not have or have relatively little contact with the user's skin depending on the The diaper particular design and therefore the outer zones 72 need not be as soft as the central area 70. However, the outer zones 72 are subjected to stresses or stresses that are elatively elevated during use and / or manufacture and therefore they need to be relatively resistant as compared to the central zone 70. With the thermally bonded nonwoven webs, the amount of bonded area of the frame is a factor in determining the smoothness and also resistance to Id tension of the frame. As the area of the weft increases, the softness decreases and the resistance to stress increases. In contrast, as the area of the weft decreases, the softness increases and the tensile strength decreases. In order to provide a nonwoven web 40 having a central area 70 relatively and relatively resilient outer zones 72, there must be a difference in the amount of the bonded area between the central zone 70 and the outer zones 72. The central zone 70 should have a relatively smaller bonded area to provide the desired smoothness and areas external 72 must have a relatively larger area to provide the desired strength. The central zone 70 preferably has a smaller bound area of about 12%, more preferably from about 5% to about 12%. The outer zones 72 preferably have a bonded area of S & amp; S & ^^^^ jj ^^ * ¡^^^^^ - ** more than about 15%, more preferably from about 15% to about 25%. The amounts of the specific bonded areas can be selected to provide the desired properties of softness and strength as long as there is a relative difference in the amount of the bonded area between the central zone 70 and the outer zones 72. The bonded areas are comprised of many. individual unions. The individual joints can be of different shapes and sizes. For example, individual joints can be circular, square, rectangular, linear, triangular, oval, elliptical, curvilinear, etc. The individual junctions may be arranged in a pattern or may be random. The nonwoven web 40 comprises a material! fibrous formed to papir of meltable fibers or polymer filaments. The nonwoven web can be formed from any of the following polymers: polyamides, polypropylene, oxypropylene copolymers, two components, polyethylene, polyethylene terephthalate, combinations of the same, and the like. Suitable materials include dry-laid or carded webs, random and air-laid webs, spin-linked webs, meltblown webs, spin-linked webs, and webs joined by continuous or caiandreous air. The fibers may be of various sizes with fibers having a denier of between about 1 and 18 being preferred. The non-woven web 40 0 preferably has a basis weight of about 5 g / m2 to 100 g / m2, more preferably about 5 g / m2 to about 60 g / m2. The nonwoven web 40 preferably has a caliper from about 0.1 mm to about 5.0 mm, and more preferably from about 0.1 mm to about 2.0 mm. In order that the topsheet be able to handle both fecal material and urine, the central zone 70 preferably comprises an effective open area and a ^^^^^^^^ J ^^^^^^^ + J - ^^^^^^^^^^^^^^^^^^^^^^^^^^^ ^^^^^^^^^^ "^^^^^^^^^^^ ¿^^^^^^^^^^^^^^^^^^" plurality of apertures with an effective size. The central zone 70 comprises a plurality of openings 46 with an effective opening size of at least 0.2 mm 2, more preferably, the plurality of openings have an effective opening size < of at least 0.5 mm.sup.2, even more preferably, the plurality of openings has an effective aperture size of at least 1.0 mm.sup.2, and most preferably, the plurality of apertures has an effective aperture size of at least 2.0. mm2 Effective openings are those that have a gray level of 18 or less on a standard gray level scale of 0-255, under the image acquisition parameters described below. The central zone 70 preferably has an effective open area of at least 10 percent, more preferably the central zone 70 has an effective open area d at rnenos 15 percent, even more preferably, the 3rd central zone 70 has a Effective opening of at least 20 percent, and very preferentially the central area! 70 has an effective open area of at least 25 percent. Ei size of effective opening and effective open area are determined by the following procedure using the image analysis described abaj The procedure has three principal steps: image acquisition, ie, obtaining representative images of areas on the surface of a zone! central 70; image measurement; that is, measure the percentage of! open area of an image and of individual apertures in their perimeters: and data analysis, i.e., exporting measurements percentage open area, individual area and aperture perimeter to a spreadsheet where calculations' distribution are of frequency, sum of distribution of area and hydraulic radii. An image analysis system that has a picture taking card, a microscope, a camera and an image analysis software are used. A DT2855 checkout card model available from Data is provided ^^ »^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ ^^^ g ^^^^^^^^^ Translation from Marlboro, Mass. A microscope with VH5900 monitor, a video camera, is also provided, which has a VH50 lens with a contact-type lighting head available from Keyence Company of Fair Lawn, NJ and it is used to acquire an image that will be saved in the computer file. The Keyence microscope acquires the image and the frame taking card converts the analog signal of this image into a digital format readable by the computer. The image is saved in a computer file and measured using the appropriate software such as the image analysis software Optimus, version 3.1, available from BioScan Company of Edmaons, Wash. In order to use Optimus image analysis software, the computer must have Windows software, version 3.0 or later, available from Microsoft Corporation of Redmond, Wash. And also have a CPU at least equivalent to the Inte) 80386. Can you use any suitable personal desktop computer, with a personal computer type 486 DX3? which has been found to be particularly suitable. The images that are saved in and returns to the sea from. The file was displayed on a Sony Trinitron monitor model PVM-1343MO with a final display amplification of approximately 50X. The image acquisition step, noted above, requires 10 different regions from a sample of representative material to be tested. Each region is rectangular, measuring approximately 5.8 mm by 4.2 mm. The sample is placed on a black grid board to increase the contrast between the openings and the portion of the sample that defines the openings. The mean gray level and the standard deviation of the black grid board were 16 and 4, respectively. The images are acquired with the room lights off using the Keyence monitor microscope mounted on a copying platform directly above the sample. The Keyence light source that illuminates the sample is adjusted and monitored with the Optimas software to measure the average level of gray and the ? i * á * ámÉ ¡ám '- "¿fc ^^^^ - ^ jaL. standard deviation of a density prism Q.3 on a Kodak gray scale available from Eastman Kodak Company of Rochester, New York. The control of the Keyence lighting source is adjusted in such a way that the average gray level of the illuminated prism is 111 + 1 and the standard deviation is 10 + 1. All the images were acquired during a single period of time and the source of Keyence light is monitored by measuring the average gray level and the standard deviation of the prism throughout the image acquisition process. When measuring an individual opening, only the effective size of the opening is of interest. By measuring the effective aperture size, the size of the aperture intended to contribute to the porosity of the material is quantified and the contributions of the fibers and the bundles of fibers passing through an area intended to be an aperture are quantified. An effective opening is a hole through matter! which has a gray level less than or equal to 18 using the image acquisition parameters co or described here. In this way, an attempted opening can be divided into the plurality of effective openings between the transverse fibers. The image analysis software is calibrated in millimeters by means of a governing image acquired from the sample images. A filter averaged 3 by 3 pixels! found in the image menu Optimum 3.1 applies to each saved image to reduce noise The openings are detected in the gray level range from 0 to 18. An aperture that is not fully contained within a viewing area of 5.8 by 4.2 is not considered in the individual area and perimeter measurements. Therefore, the averages and distributions of area and perimeter are not affected by openings that are not fully contained within the field of vision. However, individual openings that can not be fully seen in the image are included in the calculation of the open area percent. This difference occurs because the percent of open area is simply the image of pixel ratios from 0 to 18 with respect to the total number of pixels in the image Areas that have a gray level of 19 or greater were not counted in the calculation of the open area. The percentage of the open area for the average of 10 images for each material is measured using the Optima image analysis software. The percentage of open area is defined as the proportion of the number of pixels that have a gray level from 0 to 18 with respect to the total number of pixels for the image. The percentage of the open area is measured for each image representing a particular region of a sample. The percentage of open area from each of the 10 individual images is then averaged to produce a percentage of open area for the total sample. The data analysis is conducted using an Excel spreadsheet, also available from Microsoft Corpion of Redmond, Washington. The Excel spreadsheet organizes measurements of the percentage of open area, e? opening area, and the opening perimeter, obtained from! Optimal software The averages and standard deviations of the sample, size and frequency distributions of the individual areas of the aperture and the hydraulic radius calculations (area divided by the perimeter) for the individual openings are obtained using the spreadsheet . The distributions of the individual area of the opening are also calculated using the Excel spreadsheet. The openings are classified in deposits of certain size ranges. The number of opening areas that fall within certain ranges of interest size is also determined as the sum of the areas within each range. The intervals are established in increments of 0.05 square millimeters. These areas are expressed as a percentage of the total open area of the sample. The frequency and sum of the area distributions are obtained by combining the individual aperture measurements from all 10 images for each sample.

The openings 46 in the central area 70 may vary in size, shape and pattern. Examples of some possible forms include but are not limited to circular, square, rectangular, oval, triangular, dog bone, star, oblong, etc.

The openings 46 can be arranged in a systematic, uniform or random pattern. A systematic pattern with similarly dimensioned openings is preferred. In another embodiment, the outer zone 72 may also have an effective open area and a plurality of openings with an effective size similar to that of the central zone 70. The outer zone may have an effective open area of at least! About 0 percent of a plurality of openings with an effective size of at least 0.2 square millimeters. Referring now to Figure 2, there is shown a schematic illustration of a process 200 for forming the frame of the present invention. A non-woven material 240 is unwound from a supply rale 210 and travels on i? dilection indicated by the arrows associated therewith as the supply roll 210 rotates in the direction indicated by the arrows associated therewith. The nonwoven web 240 as a uniform predetermined joined area. The bonded area of the non-woven web 240 in this step has a predetermined bonded area for the central area 70. For purposes of illustration, the bonded area of the non-woven web 240 is 10%. The nonwoven web 240 having a unified uniform area of 10% is fed through the bonding apparatus 250 formed by the rollers 252 and 254. The bonding apparatus 250 adds additional links to only the outer areas 272 of the web 240. For example, the joining apparatus 250 adds 10% of the area attached to the outer zones 272 such that the outer zones 272 have a joined area of 20% and the central zone 270 has a joined area of 10%. The roller 252 includes a plurality of projections 256 extending around a portion of its outer surface. The roller 252 is preferably constructed of steel. The roller 254 has a smooth outer surface and is preferably constructed of steel. As can be seen in Figure 3, the joint projections 256 are placed only in the outermost portions 252 to correspond to the outer areas 272. The non-woven web 240 is then fed through the grip 260 of an apparatus perforator 262 formed by rollers 264 and 266. Roller 266 has a smooth outer surface and is preferably constructed of steel. Eg roll 266 can nevertheless be constructed of other materials. The roller 264 includes a plurality of projections 268 extending around a portion of its surface external. The roller 264 is preferably constructed of steel. The rolls 264 and 266 have the same speed. The rolls 264 and 266 are heated. Preferably the roll 264 is heated to have a higher temperature than the roll 266. As the nonwoven web 240 passes through the gripping space 260, the central area 270 is drilled. As the center 270 is drilled, the The material is heated above its melting point in such a way that at least a portion of the perimeter of the openings melts. As can be seen in Figure 4, the projections 268 are placed only in the central portion of the roller 262 for correspond to the central area 270 of the frame 240. The central area 270 now comprises a plurality of openings 246 After the central area has been perforated! 270, the non-woven web 240 is then cooled to deposit the web after leaving the apparatus 262. In Fig. 2, the web 240 is shown to be cooled by blowing cold air over the web 240 from a fan 280. Of course other known techniques can be used to cool the web 240. Cooling the web solidifies the molten material that extends around the perimeter of the openings.

After cooling, the web is fed through the gripping space 290 formed by the rollers 292 and 294. The rollers 292 and 294 have the same speed. The rollers 292 and 294 have smooth external surfaces. The rollers 292 and 294 are preferably constructed of steel. However, other suitable materials can also be used to build the rollers 292 and 294. The rollers 292 and 294 break the molten solid material extending around the perimeter of the openings. The breaking of the molten solid material increases the softness of the weft. The peripheral linear speed of the rollers 292 and 294 is preferably greater than the peripheral linear speed of the rollers 264 and 266 tensioning the material between the two sets of rollers. By adjusting the speeds of the rollers, the material is tensioned in such a way that it achieves a desired quantity. From the gripping space 290 the web 240 is preferably wound on the tension roller 296 The central area! 270 can be treated with additional agents, such as, sprayed to create the desired fluid handling properties. For example, fa zone 15 centers! 270 can be treated with a lotion. In addition to the process described above, the web can be perforated within the central zone 270 by other known processes. For example, the central zone can be perforated by needle puncture, hydro perforation or other known processes. Referring now to Figure 5, there is shown a schematic illustration of another embodiment of a process 300 to form a frame of the present invention. A plurality of loose fibers 310 are fed from a carding apparatus 305 directly to a joining apparatus 330. Of course, other apparatuses may be used such as the spinning linking apparatus or a blown apparatus in the molten state.

The joining apparatus 330 is different from the apparatus 250 shown in Figure 2, since the apparatus 330 provides both a central zone with relatively smaller joined area and external zones with relatively larger joined areas. The attachment apparatus 330 comprises rollers 332 and 334. The roller 334 has a smooth outer surface and is preferably constructed of steel. As can be seen in Figure 6, the roller 332 includes a central attachment area 340 and two external attachment zones 350. The central attachment zone 340 includes a plurality of projections 342 extending around the outer surface of the roller 332. outer zones 350 include a plurality of projections 352 extending around the outer surface of the roller 332. The projections 342 within the central zone 340 are arranged to provide a relatively low joined area, for example a 10% joined area, and the projections 352 within the outer zones 350 are arranged to proportionally "a relatively larger joined area, for example a 20% joined area." After leaving the joining apparatus 330. the frame comprises a central area 370 having a joined area of 10% and two external zones 372 having a joined area of 20% Although the joining apparatus 330 is shown to comprise two rollers 332 and 334, the apparatus may comprise multiple rollers to provide the areas, joined from the central zone 370 and the outer zones 372. From the joining apparatus 330, the weft is then perforated 362, cooled 380, and the fused perimeters of the openings are broken 390, and the The web is wound on a tension roll 396. These steps are similar to the steps discussed above with respect to the process 200 illustrated in Figure 2. Although in the above embodiments the plot has been described as having a central zone and a pair of external zones. , the plot may also have additional zones if desired. ^^^ «^^ rf ^^ ^^^ j ^^ gg ^ í ^^^^^^^^ fc ^ fa; The diaper 20 may further comprise elastic cuffs for the leg (not shown) which provide improved fluid containment and other body exudates. Each elastified fold for the foot can comprise several different modalities to reduce the leakage of the exudates from! body in the leg regions. (The leg fold can be and is sometimes also referred to as leg bands, side flaps, bar folds, or elastic folds.) U.S. Patent No. 3,860,003 discloses a disposable diaper 20 that provides a collapsible leg opening having a side flap! and one or more elastic members to provide an elastified fold for the leg (packing gusset). The commonly assigned United States Patent No. 4,909,803 entitled "Disposable Absorbent Article Having Elasticized Fins" issued to Aziz et al. On March 20, 1990, discloses a disposable diaper 20 having "elastified fins" erect "(folds of barrier) for better containment of leg regions. The commonly assigned United States Patent No. 4,695,278 entitled "Absorbent Article with Double Folds" issued to Lawson on September 22, 1987, describes a disposable diaper 20 having double folds including a gusset fold and a barrier fold. The diaper 20 preferably further comprises an elastic waist feature (not shown) that provides for improved fit and containment. The characteristic of elastic waist is that portion or area of the cloth! 20 which is intended to expand and contract elastically to dynamically adjust to the waist of! user. The elastic waist feature at least 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 characteristics of elastic waist, one placed in the first region of waist 27 and one placed in the ca = ^ iass second waist region 2, although diapers can be constructed with a single elastic waist feature. In addition, although the elastic waist feature or any of its constituent elements may comprise a separate element secured to the diaper 20, the elastic waist feature is preferably constructed as an extension of other diaper elements 20 such as the back sheet 26 or the sheet upper 24, preferably both backsheet 26 and upper sheet 24. The elasticized waistband can be constructed in a number of different configurations including those described in U.S. Patent No. 4,515,595 issued to Kievit et al. on May 7 1985 and the aforementioned U.S. patent application Serial No. 07 / 715,152; each of these references being incorporated herein by reference. The diaper 20 also comprises a fastening system 36 that forms a lateral closure that maintains the first waist region 27 and the second waist region 29 in an overlapping configuration such that lateral stresses around the waist are maintained. circumference of diaper 20 to maintain diaper 20 on the wearer. Illustrative fastening systems are disclosed in U.S. Patent No. 4,846,815 entitled "Disposable diaper having an improved fastening device" issued to Scripps on July 11, 1989; U.S. Patent No. 4,894,060 entitled "Disposable diaper with improved hook fastener portion" issued to Nesiegard on January 16, 1990; the commonly assigned patent of the United States No. 4,946,527 entitled "Pressure sensitive adhesive fastener and method for making the same" issued to Battrell on August 7, 1990; the commonly assigned U.S. Patent No. 3,848,594 entitled "Disposable diaper tape fastening system" issued to Buell on November 19, 1974; the commonly assigned United States Patent No. B1 4662,875 entitled "Absorbing Article" issued to Hiroisu et al. on May 5, 1987; and the here above US Patent Application No. 07 / 715,152; each of which are incorporated herein by reference. The diaper 20 is preferably applied to a wearer by placing one of the waist regions, preferably the second waist region 29, under the wearer's back 5 and pulling the rest of the diaper 20 between the user's legs in such a way that the other waist region, preferably the first waist region 27, is positioned across the front of the user. The tape tabs 36 of the fastening system are then released from the release portion. The person who places the diaper then wraps the elastified side panel around the wearer, while still holding the tab portion. The fastening system is secured to the outer surface of the diaper 20 to effect two lateral closures. Although the particular embodiments of the present invention have been illustrated and described, it would be obvious to those skilled in the art that various changes and modifications may be made without further modification. depart from the spirit and scope of invention. Therefore, it is intended to protect all the changes and modifications within the scope of this invention in the appended claims.

Claims (17)

1. CLAIMS 1 A nonwoven web, characterized by: said web having a first zone and at least a second zone, said first zone and said second zone having a joined area, the joined area of the second zone being greater than the bound area of the second zone. first zone, the first zone having an effective open area of at least about 10 percent and a plurality of openings with an effective size of at least 0.2 square millimeters.
2. 2. The frame according to claim 1, wherein the first zone cor- responds to a central zone and the second zone comprises an external zone.
3. 3. The frame according to claim 2. wherein the frame comprises a pair of external zones.
4. 4. The frame according to any of claim 2 or 3, ', r: wherein the central zone has an effective open area of at least about 15 percent.
5. The frame according to either of claim 2 or 3 , wherein the central zone has a plurality of openings with a size of at least 1.0 square millimeters.
6. 6. The frame according to any of claims 2 to 5, wherein said central zone has a bonded area of less than 12%.
7. 7. The frame according to any of claims 2 to 5, wherein the central zone has a bound area of 5% to 12%.
8. 8. The frame according to any of claims 2 to 5, wherein the outer zones have a joined area of more than 5%. ? _? ¿¡¡, ^^: áfc;
9. 9. The frame according to any of claims 2 to 5, wherein the outer zones have a bound area of 15% to 25%.
10. 10. A disposable absorbent article comprising a liquid permeable top sheet comprising the web according to any of the preceding claims.
11. The disposable absorbent article according to claim 10, further comprising a backsheet attached to the topsheet, and an absorbent core positioned between the topsheet and the backsheet.
12. 12. A method for forming a united nonwoven web, the method comprising the steps of: a) joining the web in a first or central zone with a bonded area; b) joining the frame in at least a second or external zone with a joined area greater than the joined area of the central zone; c) perforate the central zone so that the central zone has a plurality of openings.
13. 13. The method according to claim 12, wherein the central zone has an effective open area of at least about 10 percent.
14. The method according to claim 12, wherein the openings have an effective size of at least 0.2 square millimeters.
15. The method according to any of claims 12 to 14, wherein the central zone has a bonded area. of less 12%.
16. 16. The method according to any of claims 12 to 14, wherein the outer zones have a joined area of more than 15%.
17. 17. The method according to any of claims 12 to 14, wherein the frame comprises a pair of external zones.