MXPA97005286A - Process of formation of absorbent nucleus of non-waste and products derived from absorbent materials based on tr - Google Patents

Abstract

There is disclosed herein a multi-layer absorbent core having an ear section, a crotch section and a rear ear section, wherein the length in the machine direction of said crotch section is matched with the length in the direction of the combined machine of the front ear section and the rear ear section, with the angle and radius forming the transition from the crotch width to the same ear width, said core being suitable for use in an absorbent article , and a method for manufacturing said absorbent and multi-layer core. The method comprising providing a single weft (10) of absorbent core material from a roll, in which the weft having longitudinal, straight, parallel lateral edges, continuously conveying said weft of absorbent core material in the machine direction; cutting (12) continuously said web of absorbent core material longitudinally into weft sections having at least one full pattern strip (14) having a repeating, hourglass shape and first (16) and second (18) cut-away side pieces, each of said cut-away side pieces provides a strip of the partial pattern having a straight edge defined by one of longitudinal, straight, parallel lateral edges of said frame and a longitudinal, non-linear, opposite edge that have a pattern or pattern corresponding to one of said longitudinal edges of said strip of the complete model (14), continuously orienting said lateral pieces cut into relation to said strip of the complete model (14), such that the ear sections and the crotch section of the cut-out side pieces are superposed in superposition with said strip of the complete model (14) to form a composite strip (24) of layers multiple, continuous, and successively cutting the composite strip (24) in the transverse direction at predetermined intervals to form discrete absorbent cores (26) of multiple layers.

Description

PROCESS OF FORMATION OF NON-WASTE ABSORBENT NUCLEUS AND PRODUCTS DERIVED FROM MATERIALS TRAM-BASED ABSORBERS FIELD OF THE INVENTION The present invention relates to formed or contoured absorbent cores made of multiple pieces or layers, of absorbent material derived from weft-based materials that are useful in absorbent articles, such as diapers, adult incontinence briefs, sanitary napkins and the like. This application also relates to a process for making such formed or contoured absorbent cores that essentially eliminate the general waste in the production of the formed absorbent cores.

BACKGROUND OF THE INVENTION Articles for incontinence management, such as disposable diapers without fabric, have traditionally used absorbent structures comprising entangled masses of fibers, i.e., nonwoven fibrous webs. These wefts imbue aqueous fluids, including discharged body fluids, both by means of an absorption mechanism where the fluid is captured by the fiber material by itself, and it is especially by means of a wicking mechanism where the fluid is acquired by distributed through and stored in the capillary interstices between the fibers. These webs often comprise layers of low density absorbent fibers, compacted without coefficient such as carded cotton webs, cellulose fibers placed in air, crushed fibers of wood pulp, and the like. The fibrous webs used in such absorbent articles also often include certain gelling absorbent materials usually referred to as "hydrogel materials," "super absorbent," or "hydrocolloid" for storing large amounts of discharged body fluids. See for example, U.S. Patent No. 3,699,103 (Hafery others) issued June 13, 1972, and U.S. Patent No. 3,770,731 (Harmon), issued June 20, 1972, which disclose the use of particulate gelling absorbent materials in absorbent articles. Actually, the development of thinner diapers has been the direct consequence of thinner absorbent cores that take advantage of the ability of these gelling absorbent materials to absorb large amounts of discharged aqueous body fluids, especially when used in combination with a fibrous matrix. See, for example, U.S. Patent No. 4,673,402 (Weisman et al.), Issued June 16, 1987, and U.S. Patent No.

No. 4,935,022 (Lash et al.), Issued June 19, 1990, disclosing double-layer core structures comprising a fibrous matrix and particulate gelling absorbent materials useful in the production of compact, thin, non-bulky diapers. These particulate gelling absorbent materials are excellent in commerce for their ability to retain large volumes of fluids such as urine. A representative example of said particulate gelling absorbent materials are the slightly interlaced polyacrylates. Like many other gelling absorbent materials, these slightly entangled polyacrylates comprise a multiplicity of anionic (charged) carboxyl groups attached to the polymer structure. It is these charged carboxyl groups that enable the polymer to absorb aqueous body fluids as a result of the osmotic forces. In addition to osmotic forces, absorbency based on capillary furrows is also important in many absorbent articles, including diapers. The capillary forces are remarkable several everyday phenomena, as exemplified by a paper towel that absorbs spilled liquids. Capillary absorbents can offer superior performance in terms of acquisition speed and conduction due to fluid wicking, that is, the ability to move aqueous fluids away from the initial point of contact. Indeed, of the double-layer absorbent core structures of Wesisman et al. And Lash and others noted above, they use the fibrous matrix as the primary vehicle for capillary transport to move the initially acquired aqueous body fluid throughout the entire absorbent core. such that it can be absorbed and retained by the particulate gelling absorbent material placed in layers or zones of the core. The fibrous structure described by Weisman et al. And Lash et al. Are produced through air placement technology. This technology involves air placement of the fibers in the cavities formed on a sifted drum to form the core shape and control the amount of material used per core. The excess overfill of the formed cavities is removed and returned to the incoming or incoming air stream by means of a splicing roller. The gelling absorbent materials (AGM) are added to the air stream together with the fiber materials. This process allows many alternate forms to be produced through the changes in the configuration of the screen placement drum. Therefore, the shape of the material is achieved by "molding" the fibers in the formed cavities. This process provides the form without edging, which in turn results in minimal waste. An alternative absorbent material potentially capable of providing capillary fluid transport would be the open cell polymeric foams. If the open cell polymeric foams are made properly, they can provide capillary fluid transport and storage acquisition aspects required for use in high performance absorbent cores for absorbent articles such as diapers. Absorbent articles containing such foams may possess desirable wet integrity, may provide adequate fit throughout the period the article is used, and may prevent changes in shape during use. In addition, absorbent articles containing such foam structures may be easier to manufacture on a commercial scale. For example, the absorbent cores of the diaper may simply be foamed sheets of continuous foam sheets and may be designed to have considerably greater integrity and uniformity than air-laid fibrous absorbent cores that contain particulate gelling absorbent materials. In addition to absorbency and easy fabrication, other potentially desirable properties of such foams is the ability to make formed or contoured absorbent cores having various shape configurations, fluid absorbency properties, etc. Fibrous absorbent cores that contain particulate gelling materials have often been formed or contoured, especially to provide hourglass-shaped configurations. See, for example, the double-layer absorbent core structures of Weisman et al. And Lash et al., Wherein the top layer is of an hourglass-shaped configuration. The formed or contoured absorbent cores made from open cell foam materials having particularly desirable fluid transport characteristics are described in U.S. Patent No. 5,147,345 (Young et al.) Issued September 15, 1992. The core Young's absorbent, et al., comprises a fluid acquisition / distribution component that may be fibrous or foam based, as well as a storage component, fluid redistribution comprising an open cell, flexible, hydrophilic polymer foam. Figure 9 of Young et al discloses a contoured shaped core having an hourglass-shaped fluid acquisition / distribution layer 73 comprising a fibrous absorbent material that lies on a watch-shaped fluid redistribution / storage layer of sand comprising an open cell absorbent foam. See also Figure 2, which discloses a smaller, rectangular fluid acquisition / distribution layer 51, comprising a fibrous absorbent material that lies on a larger hourglass-shaped fluid redistribution / storage layer 52, comprising a polymeric foam open cell. The formation of formed or contoured absorbent cores or layers of foam materials, including those described in Young et al., Is not without problems. The hourglass-shaped foam layers shown in Figures 9 and 2 of Young et al., Are typically made from a single rectangular piece of foam. This rectangular piece of foam can be trimmed, cut or otherwise separated to form the hourglass-shaped piece. By carrying out these operations, a significant amount of waste of unusable foam can be created. Relatively, it has been found that in the formation of the hourglass shaped pieces of foam, as much as 15 to 25% of the total foam material used may end up as waste unusable. In addition, the unit-shaped hourglass foam pieces can create certain problems in terms of the comfort of the absorbent article, in which the absorbent foam core is used. In the case of absorbent foams with larger modules, the unit cores in the shape of an hourglass can be less soft and less flexible. This is especially true in the crotch area of an absorbent core made from a layer of absorbent, unitary, hourglass-shaped foam. It would therefore be desirable to be able to make formed or contoured absorbent cores of polymeric foams which: (1) reduce the generation of foam waste, and (2) provide greater softness and flexibility, especially in the crotch area. Previous product designs for formed absorbent core structures generated from rectilinear rolls of woven raw material have generally produced significant amounts of waste, which must be discarded or recycled during the manufacturing process. The designs that use the multiple rollers of several widths of material to generate the form, are a little difficult to execute, especially when these use very narrow wefts of material. Large rollers with narrow wefts are very difficult to manufacture and also make processing of the absorbent articles difficult. Preliminary attempts have been made to reduce the amount of waste material produced during the manufacture of the pattern-based articles derived from a continuous web. For example, each of U.S. Patent No. 4,760,764 to Jonckheere et al. And EP 0539 032 A1 of Johnson &; Johnson describes a manufacturing method with a reduced amount of waste material, in which a continuous web of material is continuously cut into a cyclic pattern to provide two strips, each having a longitudinal edge and a straight edge made according to model. The strips are transversely displaced in a directional, offset manner such that the tabs are aligned and then joined together in an overlapping manner to form a two-layered central region that produces the edge contour of the final disposable absorbent product. These products are limited to a single design structure that has only two layers in the central region, with only one layer in the ear or tabular areas. Although this model or pattern can be repeated a higher part of itself, the number of layers in the central region will be double that of the layers that are present in the outermost formed regions. Such an arrangement, although potentially effective from a fluid absorption point of view, is less desirable from a point of view of rigidity, flexibility, total thickness and minimization of the crotch volume. U.S. Patent No. 3,072,123 (Davis), January 8, 1963, shows a plurality of adjacent cut lines in wave form, forming nested shapes which are then further processed to form an absorbent article. Since this request is essentially intended to produce a unitary structure of nested forms, the most external, partial forms do not provide utility and therefore result in waste material. This approach is different from that of the present one which uses the partially formed segments as well as the integral forms, thus resulting in essentially "no or no waste". U.S. Patent No. 3,878,286 (Jones), April 15, 1975, is intended to produce nested absorbent structures, however, as in U.S. Patent No. 3,072,123, the outermost areas of the weave that contain only structures or partial forms, lack utility and therefore result in waste material. The Patent of the States No. 4,862,574 (Seidy), September 5, 1989, illustrates a method for producing a panty liner. Although this request does not show a repetitive cut pattern or a wave type pattern, the pattern is in the transverse direction and is not continuous in the direction of the machine or the pattern. Therefore, the approach of U.S. Patent No. 4,862,574, produces discrete components against the intent of the present invention, which is to produce a continuous pattern resulting in multiple frames of product forms in a continuous frame. The uncoupled cutting pattern in U.S. Patent 4,862,574 results in partial structures, which, as in the previously distinguished patents, do not provide utility with respect to their respective inventions. U.S. Patent No. 3,527,221 (Croon et al.) September 8, 1970, shows a wave type cut pattern used to form the outer cover, the frame, of a diaper. Although this approach results in minimal waste, this does not apply to the absorbent structure per se, and also does not involve stratification of the separate structures such as the present invention. U.S. Patent Nos. 5,102,487, 5,034,007; 4,595,441 and ,330,598 disclose continuous strips of materials in conjunction with repetitive patterns, none of these inventions is intended to provide absorbent core structures. Also, none of the aforementioned patents involve more than two strips of material as does the present invention. Furthermore none of the prior art references teaches the fabrication of an absorbent core structure having a plurality of layers of absorbent material in the crotch area and in the "ear" or "tabular" region where the absorbent core structure it is formed from a single frame, while the formation of waste is eliminated. Therefore, it is a main object of the present invention to provide a manufacturing method for producing a core absorbent material from a single web of material, such that there is "no waste". It is another object of the present invention to provide a manufacturing method for producing an absorbent structure having at least two layers of a core absorbent material in both the crotch area and the "ear" portions of the absorbent structure, in which forms the core structure of a single web of absorbent material. It is another object of the present invention to provide a manufacturing method for producing a variety of absorbent core structures from a single web of absorbent material, having different configurations depending on the intended use of said absorbent cores. It is still another object of the present invention to provide an absorbent core structure having greater absorbent efficiency and improved softness and flexibility for use in the production of diapers, incontinence products, etc.

BRIEF DESCRIPTION OF THE INVENTION According to the present invention, a single roller of an absorbent material having a predetermined width is fed to a die cutter, such as a rotating blade, where one or more specific patterns or patterns are cut (together with a set of intermittent cracks or cracks), and the single frame is separated into 3 or more individual frames, depending on the design of the product. By designing the pattern cut such that certain restrictions are met as defined below, several strips or pieces can be cut and aligned in such a way that they exactly nest and conform precisely to the final product of the desired core. The present invention not only provides a method for the manufacture of an efficient absorbent core material from a single material roll, but also provides a product where the shape produces a better fit and the multiple stratification produces greater softness and flexibility to the product during use. By using multiple stratification, the thickness of the weft can be minimized, and in this way, the amount of material used in core manufacturing is maximized, reducing shipping and storage costs. Furthermore, the present invention provides the manufacture of said core absorbent materials without substantial accumulation of waste material, thereby eliminating the need for an additional step to dispose of or recycle the excess material. In order to achieve zero waste, the following constraints must be maintained during the formation of the core material configuration as illustrated in Figure 21: (1) The most important restriction is the longitudinal distances of the crotch sections and ear. With reference to figure 21, the distance b = a + c where a is the distance from the front edge of the front ear of the core to the midpoint through the transition between the front ear of the core and the core crotch, the distance b is from the midpoint of the transition between the frontal core and the crotch of the nucleus towards the midpoint of the transition between the core crotch and the posterior ear of the nucleus, and the distance c is from the midpoint of the nucleus. transition between the crotch of the nucleus and the posterior ear of the nucleus towards the end of the posterior ear of the nucleus; (2) The width of the front ear is matched to the width of the posterior ear; and (3) The transitions between the ears and the crotch should be symmetrical. In a first embodiment of the invention, a single wide web of absorbent material is fed from a roller to a die cutter to provide a main weft trimming having the desired pattern or pattern of the final product and two cut-out pieces formed throughout of the side edges of the weft, where the trimmed pieces are transported towards a position in the upper part of the strip of the complete model. According to one aspect of this embodiment, the two cut pieces are placed on top of the strip of the complete model in a fully layer form, wherein the core has three layers of absorbent material in the total crotch portion and two layers of absorbent material in the ears of the core. In a demonstration, the two cut pieces are placed in a partially laid top layer, where the core has three layers in the longitudinal central region of the crotch area and two layers in the longitudinal side regions of the crotch area and two layers in the crotch area. ears of the nucleus. In a second aspect, the two cut pieces are placed in the same plane. As a first manifestation, the two cut pieces of the absorbent material are placed in a "splice" shape, wherein the core has two layers of absorbent material in the total crotch area and two layers in the ears of the core. As a second manifestation, the two cut pieces are placed in an "open" shape, where the core has a single layer of absorbent material in the longitudinal central area of the crotch and two layers of material in the longitudinal side areas of the crotch. crotch and the ears of the nucleus. For the purposes of the present invention, "splicing" means that the trimmed pieces are intended to touch along the straight edges of the trimmed pieces. The term "opening" is intended to imply that the straight edges of the cut-out parts do not touch and that the cut-out parts do not overlap. Alternatively, the two cut pieces can be separated from the weft and oriented with their longitudinal straight edges juxtaposed to each other to form the first desired pattern and then the strip of the complete pattern can subsequently be superimposed on the cut pieces. In a second embodiment of the invention, a single broad sheet of absorbent material is fed from a roll to a die cutter to provide two main webs juxtaposed with each other along a common center edge and misaligned one from the other, in such a manner that the tabs of one frame correspond exactly to the notches of the other frame, each frame having the desired model of the final product; and two cut-out pieces formed along the side edges of the weft, where the cut-out pieces are transported to a position where they can be sandwiched between the two cut-out plots in a partial or total overlap form, to provide a core that it has 4 layers of absorbent material in the crotch portion and 3 layers of absorbent material in the core ears, or in a "splice" or "opening" shape to provide a core having 3 or 2 layers, respectively, of absorbent material in the crotch portion and 3 layers of absorbent material in the core ears. Alternatively, cut-out pieces may be transported to a position in the upper part of or under the two main frames in a partial or full overlap configuration in a "splice" or "open" manner. In a third embodiment of the invention, a single wide web of absorbent material is fed from a roller to a die cutter to provide a main screen main cut having the desired pattern of the final product and two cut pieces formed along the the side edges of the frame, where the cut pieces are twisted or rotated 180 ° before being superimposed on the strip of the complete model. In this embodiment, the upper surface of the cut-away side piece faces the upper surface of the full pattern strip. As in the first and second embodiments, the two cut-out side pieces may be placed on top of the full pattern strip in a total overlap form or in a partial overlap form to provide a first aspect of the third embodiment, in where the core has three layers of absorbent material in the crotch portion and two layers of absorbent material in the ears of the core, or the two cut strips may be in the same plane as in a "splice" or "opening" shape "to provide another aspect of this modality. In another embodiment of the invention a single broad sheet of absorbent material is fed from a roll to a die cutter to provide two main webs juxtaposed with each other along a common center edge and misaligned one from the other, such that the tabs of one frame correspond exactly to the notches of the other frame, each frame having the desired model of the final product; and two cut-out pieces formed along the side edges of the weft where the cut-out pieces are transported to a position where the two cut-out frames are walled, in a full or partial overlap to provide a core having 4 layers of absorbent material in the crotch portion and 3 layers of absorbent material in the core ears, or in a "flat splice" form or an "aperture" shape to provide a core having two or three layers of absorbent material in the crotch portion and 3 layers of absorbent material in the core ears. Alternatively, the cut-out pieces can be transported to a position at the top of the two main frames in a partial or total overlap configuration or in a "flat or open" splice or "flat" shape or form.

BRIEF DESCRIPTION OF THE DRAWINGS Although the description concludes with the claims pointing out in a particular way and claiming differently to the subject matter of the present invention, it is believed that the invention will be better understood from the following description and drawings, in which like reference numbers identify similar elements.

Figure 1 is a perspective view illustrating a method for manufacturing the core of the present invention. Figure 2 is a perspective view illustrating a variant of the method shown in Figure 1. Figure 3 is a perspective view illustrating another method for manufacturing the absorbent core of the present invention. Figure 4 is a perspective view illustrating a variant of the method shown in Figure 3. Figures 5a to 5d are top plan views of a single wide weft of absorbent material showing a pattern or pattern cutout in accordance with a aspect of the first embodiment of the invention, in which the cut pieces overlap. Figures 6a to 6b are top plan views of a single wide web of absorbent material showing a cut-out of the pattern according to another aspect of the first or second embodiment of the invention, in which the cut-out pieces splice. Figures 7a to 7b are top plan views of a single wide web of absorbent material showing a cut-out of the pattern according to another aspect of the other first or second embodiment of the invention, in which the cut-out pieces form a opening. Figures 8a-8d are top plan views of a single wide weft of absorbent material showing a trimming of the pattern according to another aspect of the second embodiment of the invention. Figure 9 is a top plan view illustrating an absorbent core structure according to one aspect of the embodiment of the invention, showing the cut-away pieces overlapped in a fully overlapped manner. Figure 10 is a cross-sectional view of the core absorber structure of Figure 9 taken along section line 9-9. Figure 11 is a top plan view illustrating an absorbent core structure according to another aspect of the first or second embodiment of the invention, showing the cut-away pieces overlapping in a partial overlap format. Figure 12 is a cross-sectional view of an absorbent structure of Figure 11 taken along section line 11-11. Figure 13 is a top plan view illustrating an absorbent according to another aspect of the first or second embodiments of the invention, showing the two pieces cut into a flat splice shape. Figure 14 is a cross-sectional view of the absorbent structure of the core of Figure 13, taken along section line 13-13. Figure 15 is a top plan view illustrating an absorbent core structure according to another aspect of the first or second embodiments of the invention, showing the two pieces cut into an aperture shape. Figure 16 is a cross-sectional view of the absorbent core structure of Figure 15, taken along section line 15-15. Figure 17 is a top plan view of an absorbent core structure according to another aspect of the first or second embodiments of the invention, showing a first partially cut-out weft cut to reveal the two cut-out pieces in the partially spliced format detached to further reveal a second main central frame.

Figure 18 is a cross-sectional view of the absorbent structure of the core of Figure 17, taken along section line 17-17. Figure 19 is a top plan view of an absorbent core structure according to another aspect of the first or third embodiments of the invention, showing a first cropping cut partially cut to reveal two pieces cut out in the form of an opening, partially detached to further reveal a second main central pattern. Figure 20 is a cross-sectional view of the core absorbent structure of Figure 19, taken along section line 19-19. Figure 21 is a top plan view of a trimming pattern illustrating the shape and relative dimensions of an absorbent core of the present invention.

DETAILED DESCRIPTION OF THE INVENTION The structures of the present invention will be described in relation to their use as absorbent cores in disposable diapers, adult incontinence products, catamenial products and the like; however, it should be understood that the potential application of the structures of the present invention should not be limited to only absorbent core structures or said disposable articles mentioned above. Hereinafter, the term "disposable absorbent article" refers to any article that absorbs and contains body exudates such as urine, fecal material, menstruation, blood and the like. More specifically, this term refers to any item that is placed against or near the user's cue to absorb and contain the various exudates discharged from the cuefo, and additionally is intended to be discarded after a single use (i.e. items are not intended to be washed or otherwise restored or reused). In a preferred aspect of the invention, disposable core absorbent structures are used in a diaper product. As used herein, the term "diaper" refers to an undergarment generally worn by infants and incontinent persons, and worn around the wearer's lower torso. In general, disposable diapers comprise a liquid pervious top sheet, a liquid impermeable back sheet bonded with the top sheet, and a structure positioned between the top sheet and the back sheet. The present invention relates to the absorbent core structure and particularly to a method for manufacturing an absorbent core structure having zero waste, thereby eliminating the steps of disposing of or recycling the surplus material. Traditionally, a web of absorbent material is controlled by putting energy into the web. This was accomplished by pulling the weft in several places through jaws, S-shaped decks, etc., and the weft, in turn, drives other rollers that include guiding elements, tracking device, etc. Because of the hysteresis of certain absorbent materials which can be highly viscoelastic, it is important that the weft material is placed under minimum tension and, preferably, the tension should not exceed about 1%. In accordance with the present invention, each of the rollers in the core forming apparatus is driven independently, such that the pulse energy is not subject to the weft material. If all the rollers are driven at the same speed, no tension is imparted to the web and, in order to maintain sufficient tension to the web, the speed of each roller must not be more than 1% faster than the previous roller. Even when all the rollers are driven at the same speed, there are still places where the web is subjected to some tension. Tension is imparted when the web is traveling on a roller, and when the web is twisted during the phase change. The tension can be maintained under 1% when running the roller by an appropriate selection of the diameter of the roller. Knowing the thickness of the weft, you can set the tension to 1% and you can calculate the minimum diameter of the roller by means of the formula: d = 2T (1-3) e where t is the thickness of the frame and e is the tension. The diameter must be greater than or equal to "d". The tension in the weft is also maintained below or under 1% during twisting by selecting a minimum height of the twist roller by calculating the different path lengths of the center of the weft, and the edges of the weft as the weft passes through a helix , setting the tension at the edge to 1%, decreasing the distance h to a minimum. The propeller that the weft crosses (as illustrated in Figure 3) is also determined by the angle a of the turning roller. The angle a is determined by: a = arcsin (c d This equation only works if the trajectory of the weft is perpendicular to the rollers as it rolls in. The height of the torsion rollers, h is determined by: h = (n (core length) + b - pd) - 2 Where b is the distance between the rollers. Note that n is an independent variable and can be any integer. This represents the number of cores that the cut piece is displaced from the return phase. This (n) must be selected in such a way that h is greater than the minimum h determined previously. Clipping rollers are not fixed in place. These can rotate to keep the trimmed pieces properly aligned as they are placed over the top of the main web. The positioning of this roller and the vertical axis that rotates around it, are very important for the control and exact adjustment of the frame appropriately. The frame needs to be perpendicular to the roller, and it will follow the track to this position. During twisting, the centerline of each cut piece must remain tangent and perpendicular to each roller and to the new trajectory of the frame (or previous). The rollers are dimensioned and separated in such a way that this restriction is maintained. This determines the separation distance of the roller b. The axis around which the torsion rollers rotate is the same as the centerline of the cut-out part. In this way, the geometrical relationship between the cut piece and the torsion roller is always maintained (on the roller inlet side). This is a bit similar to a Fife® unit, which is an industrial handling plot tracking device. The present system is different in that it uses drive rollers (it uses Fife's® guide elements); uses three rollers (Fife's® uses 4); in the diameter of the roller (it uses rollers of 3 inches of diameter approximately the Fife's®); and on the vertical axis of rotation of the tracking unit. As illustrated in Figure 1, a uniform web 10 of absorbent material, fed from a single roller (not shown) is cut into a desired pattern, by a rotating punch 12 or other means to provide a cutout of the complete model 14, a first cut-out piece 16, and a second cut piece 18 according to one embodiment of the invention. After the weft is cut into the 3 wefts made according to model (1 main cut according to the pattern and two cut pieces), the cutout of the main model 14 continues in the same plane as the original weft 10, while the first cut-out piece 16 is twisted and guided by a first elevated drive roller 20, angled in relation to the center line of the machine such that the first cut-out part 16 is superimposed on the cutout of the complete model 16. Under the longer lengths traversed by the first cut-out part 16 in relation to the cutout of the complete model 14, the first cut-out part 16 is deflected in the machine direction and aligned with the cutout of the complete model 14. Before combining the cutout of the complete model 14 and the first cut-out part 16, an adhesive bonding material can be applied continuously or intermittently to the upper surface of the cutout of the complete model 14 or to the s bottom surface of the first cut-out part 16 or both surfaces, to temporarily join the layers together during processing. Other bonding methods, such as thermal bonding, which are well known in the art can be used in place of an adhesive material. The second cut-out piece 18 suffers from a similar transformation (in mirror image) as the first cut piece 16 in the second raised roll 22.

The combined web 24 continues to be transported in the machine direction to a cutting operation and a production conveyor to separate the web into discrete core structures 26 having 3 layers of absorbent material in the crotch portion 28 of discrete structure of core 26, and two layers of absorbent material in the ears 30 of the core structure 26. As illustrated in Figure 2, a uniform weft 40 of absorbent material having a width slightly wider than the weft shown in Figure 1, is cut into a first cut strip 42, a first strip of the complete model 44, a second strip of the model 46 and a second cut strip 48. After the weft 40 is cut into the 4 strips made according to the model (2 strips cut out and 2 strips of the complete model), the strips of the complete model and the second trimmed strip continue in the same plane as the original weft 40, while the first trimmed strip 42 is twisted and guided by a raised roller 50 angled in relation to the center line of the machine, such that the first cut-away strip 42 is superimposed on the first strip of the complete model 44 or the second strip of the complete model 46. By virtue of the longer lengths or longer lengths traveled or the first cut strip 42 in relation to the first strip of the complete model 44, the first cut strip is deflected in the machine direction and aligned with the first strip of the complete model 44. Just before combining the first strip of the complete model 44 and the first cut strip 42, an adhesive bonding material (not shown) can be applied continuously or intermittently to the upper surface of the strip of the complete pattern 44 or to the lower surface of the first cut strip 42 or to both surfaces for temporarily bond the layers together during processing. As the first cut-away strip is superimposed on the first strip of the complete pattern 44, the second cut-out strip 48 undergoes a similar transformation (in mirror image), as the first cut-away strip 42 in the second customized raised roller 52 that the first combined frame 54 continues to be transported in the machine direction. As the second cropped strip 48 is overlapped on the first strip of the complete model 44, the second strip of the complete model 46 is lifted by a third raised roller 56 and is subsequently superimposed on the first strip of the complete model 44 such that the first and second cut strips 42 and 48, respectively, are placed between the first and second strips of the complete model 44 and 46, respectively, to form the second combined web 64. The mixed structure 58 containing the two strips of the complete model and the two trimmed strips continue towards the cutting operation (not shown) and towards a production conveyor to separate the mixed web 58 in the discrete core structures 60 having two, three or four layers of the absorbent material in the crotch portion 62 of the discrete structure of cores 60, and 3 layers of the absorbent material in the ears 64 of the discrete core structure 60. Figures 3 and 4 are similar to Figures 1 and 2, except that the weft 80 is conveyed in the machine direction as the first cropped strip 82 and the second trimmed strip 84 are lifted by the raised rollers 85 and 87, respectively, the first trimmed strip 82 and the second one. Cropped strip 84 is bent at 180 °, such that when these are superimposed on the strip of the complete model 86, the upper surface of the trimmed strips faces towards the surface above. of the complete model strip 86. As shown in Figure 4, a second strip of the complete model 88 is lifted by the third raised roller 93 and is superimposed on the combined web 92 to form a composite web 94 that contains the first and second cropped strips 82 and 84, respectively, placed between the first strip of the complete model 86 and the second strip of the complete model 88. The composite web 94 (Figure 4) and 95 (Figure 3) are cut into core structures 94 ( Figure 4) and 97 (Figure 3) each having a crotch portion 98 and an ear portion 99. Figures 5a to 5d illustrate a uniform weft 100 having two longitudinal cuts therein to provide a first cut-away strip 102., a complete strip 104 of the model, and a second trimmed strip 106. Figure 5b shows the first trimmed strip 102 superimposed on the full strip of the model, and Figure 5c shows the second trimmed strip 106 super placed on the entire strip of the model, in which the first cropped strip 102 and the second cropped strip 106 overlap to form a combined frame structure 108. Figure 5d shows the cut of the discrete structure of the core 110. As illustrated in Figures 6a and 6b, an even weft 120 having a width slightly narrower than the weft shown in Figures 5a to 5d, is cut into a strip of the complete model 122, a first cut-out piece 124 and a second cut-out piece 126 and assembled in a manner similar to that used to provide the core structure of Figures 5a to 5d, except that the first cut-out piece 124 and the second piece cut-out 126 are spliced against one another along a straight edge to provide a raster structure 128, combined. The combined web has two layers of absorbent material to the crotch portion of the core structure and two layers of absorbent material in the ear portion 132 of the core structure. While in this embodiment it is illustrated as having the two cut pieces spliced together, it is also within the concept of the present invention to employ a still narrower weft material 140 to provide first and second cut-out pieces 142, 144, respectively, even thinner. , such that when the two cut-out pieces are supported on the upper part of the cutout of the complete pattern 146, they are preferably separated separately rather than in a splice configuration. This concept is illustrated in Figures 7a and b. Figures 8a to 8d illustrate the second or fourth embodiment of the present invention in which a uniform weft 150 of the absorbent material is to provide a first cutout of the complete pattern 152, a second strip of the complete pattern 154 simultaneously formed in a misaligned shape, a first cropped piece 156 and a second cropped piece 158. In this embodiment, the first cropped piece 156 and the second cropped piece 158 are assembled to provide a mixed material 152 of the complete model having the first trimmed piece 156 and the second trimmed piece 158, or "leaning" on the upper part of the entire strip 152 where it splices with the first cut-out part 156 and the second cut-away part 158 with one another along a straight edge. With the first strip of the complete model 152 and the two cut-out pieces 156, 158 in place, the second main strip 154 of the model is aligned with the first strip of the complete model 152 to further provide the desired pattern or pattern where the first trimmed piece 156 and the second cut-out part 158 are spliced together along their straight edges, and are sandwiched between the first full pattern strip 152 and the second full central strip 154 to provide a combined frame structure 160, in which all of the components are aligned in the desired design form. The combined web 160 is then cut transversely and separately into discrete core structures having three layers of the absorbent material to the crotch portion of the core structure, and three layers of absorbent material in the "ears" of the core structure. core. The embodiments of the present invention and the multiple configurations of each of the embodiments are better understood with reference to Figures 9 to 18 of the drawings, in which Figures 9 and 10 illustrate an aspect of the first embodiment of the invention in where the first cut strip 170 and the second cut strip 172, each extending to the total width of the crotch portion 174 at the top of the strip of the complete model 176, the second cut-out piece 172 lying on the first cut-out piece 170. As seen in Figure 10, the resulting core structure 178 has three layers of absorbent material in the crotch portion 174 of the structure 178, two layers of absorbent material in the "ears 180". In another configuration as illustrated in Figures 11 and 12 of the invention, the first cutout strip 190 and the second cutout strip 192 each extend only a partial width of the complete strip 198 of the model in the crotch portion 194. As shown in FIG. see in Figure 12, the resulting core structure 196 has three layers of the absorbent material in the central portion of the crotch portion while the outer edges of the crotch portion and the "ears" 204 have two layers of absorbent material.

As illustrated in Figures 13 and 14, the first cut-out strip 210 and the second cut-out strip 212 are placed on top of the main strip 214 of the model in a splice configuration to provide a core structure 216 having two layers of the core. absorbent material in the crotch portion 218 and two layers of absorbent material in the "ears" 220. As a further configuration of this aspect of the invention, the first cutout 210 and the second cutout 212 are in a parallel plane but are separated apart instead of being spliced together. This configuration is shown in Figures 15 and 16. In another embodiment of the invention as illustrated in Figures 17 and 18, the first cut out piece 230 and the second cut out piece 232 are placed on the upper part of the full pattern strip 234, in a splice configuration in the same manner as the cut-out pieces are placed on the strip of the complete model illustrated in Figures 13 and 14. In this embodiment, however, a second strip of the complete model 236 is placed on the part top of the 2 cut-out pieces 230, 232, such that the pieces cut between the first main cut 234 of the pattern and the second main cut 236 of the pattern are walled. As seen in Figure 18 the resulting core structure 238 has three layers of absorbent material in the crotch portion 240 of the structure and 3 layers of the absorbent material in the "ears" 242. As a further configuration of the third embodiment of the invention, the first cut-out piece 230 and the second cut-out piece 232 are in a parallel plane but separated apart from splicing together resulting in the formation of two layers in the crotch core region and 3 layers in the "ear" regions. This configuration is illustrated in Figures 19 and 20. Although 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 may be made without departing from the spirit and scope of the invention. .

Although the multiple configurations of the embodiments of the invention are particularly in Figures 1 to 20, it will be apparent to those skilled in the art that other configurations are possible. For example, in Figures 9 to 16, the first and second cut pieces can be placed on either the surface of the strip of the complete pattern, or the first and second cut pieces can be placed on opposite surfaces of the strip of the pattern. complete model. In addition to the configurations illustrated in Figures 17 to 20, both trimmed pieces can be placed on an external surface of any strip of the complete model, or the first trimmed piece can be placed on the outer surface of one strip of the complete model and the second Cut piece can be placed on the other strip of the complete model. In addition, the two cut pieces can be placed on opposite surfaces of a complete pattern strip and the other complete pattern strip can be placed in a face relationship with any surface of the first strip of the complete pattern. Obviously, the pieces cut out in the above configurations may be in an "overlap", "splice" or "opening" form as previously described. Therefore, attempts are made in the appended claims to protect all such changes and modifications that are within the scope of this invention.

Claims (10)

1. A method for manufacturing a multi-layer absorbent core having a front ear section, a crotch section and a rear ear section, wherein the length in the machine direction of said crotch section is matched with the length in the direction of the machine of said front ear section and said ear back section, said core being suitable for use in an absorbent diaper or a incontinence trick, said method comprising: providing a single web of absorbent core material from a roll, said web having longitudinal, straight, parallel lateral edges; continuously transporting said web of absorbent core material in the machine direction; continuously cutting said weft of absorbent core material weft sections having at least one strip of the complete model having a repeating hourglass shape, and first and second side cut pieces, each of said side pieces cut away provides a strip of the partial pattern having a straight edge defined by one of said longitudinal, straight, parallel lateral edges of said frame and an opposite longitudinal edge having a pattern or pattern corresponding to one of said edges longitudinal edges of said strip of the complete model; continuously orienting said strips of the complete model in relation to said at least one strip of the complete model, such that said ear sections and said crotch section of said strips of the partial model are superposed in superposition with said at least one strip of the model full; adhesively bonding said superimposed strips of the partial model to said strip of the complete model to form a continuous, multiple layer composite strip; and successively cutting said composite strip in the transverse direction at predetermined intervals to form discrete multi-layer absorbent cores, each multi-layer absorbent core comprising at least one integral layer of core material, which defines the shape of said core and two strips of the partial model, wherein the lateral edge of each of said strips of the partial model correspond to and align with a lateral edge of said core, preferably said absorbent core material is characterized as being a foamed absorbent material.

The method for manufacturing a multi-layer absorbent core according to claim 1, wherein said web of material of the subsequent absorbent core that is cut in said at least one strip of the complete model and two side pieces is transported by a plurality of horizontal rollers, said plurality of horizontal rollers comprising in succession: a first horizontal roller having a horizontal axis perpendicular to the machine direction of said frame; a second horizontal roller having a horizontal axis oblique to the machine direction of said frame; a third horizontal roller having a horizontal axis perpendicular to the machine direction of said frame; a fourth horizontal roller having a horizontal axis oblique to the machine direction of said frame; and a fifth horizontal roller having a horizontal axis perpendicular to the machine direction of said frame.

The method for manufacturing a multi-layer absorbent core, according to claim 2, wherein said second and fourth horizontal rollers are raised with respect to said first, third and fifth horizontal rollers, and wherein said raster sections are transported under said first horizontal roller, and said first cut-away side piece is transported on said second horizontal roller such that the path of said first cut-out side piece is peendicular to the horizontal axis of said second horizontal roller, and under said third horizontal roller such that said first side cut-out piece is superposed in superposition with said at least one strip of the complete model, said at least one strip of the complete model and said second side piece cut away being transported under said third horizontal roller, and wherein said second cut out side piece is perpendicular to the horizontal axis of said fourth horizontal roller and said second side cut piece is transported further under said fifth horizontal roller, such that said second cut-out side piece is superimposed in overlap with said at least one strip of the complete model, said at least one strip of the complete model having said first side piece cut overlapped on top, which is transported from simultaneously under said fifth roller.

The method for manufacturing a multi-layer absorbent core, according to claims 2 or 3, wherein said first cut-out side piece is twisted 180 ° before or subsequent to being carried on said second horizontal roller and said second side piece. cut is twisted 180 ° before or subsequent to being transported on said fourth horizontal roller.

5. A multi-layer absorbent core having a front ear section, a crotch section and a rear ear section, wherein the length in the machine direction of said crotch section is equated with the length in the direction of the machine, combined, of said front ear section and said ear back section, said core being suitable for use in an absorbent diaper or incontinence trick, preferably said absorbent core material is characterized in that it is a foamed absorbent material

6. The absorbent core of multiple layers, according to claim 5, wherein said core comprises at least one strip of the complete, integral patro, to provide at least one integral layer of the core material defining the shape of said core, and two strips of the partial model of the core material, wherein a lateral edge of each of said strips of the partial model corresponds to and aligns with a lateral edge of said core, wherein said strips of the partial model are adhesively attached said by minus an integral layer. The method for manufacturing a multi-layer absorbent core, according to claim 1, 2 or 3, or the multi-layer absorbent core according to claim 5 or 6, wherein said partial pattern strips longitudinally overlap in the central portion of said core, or extend inwardly in the same plane such that the opposite edges of the side edges of said partial pattern strips splice along a midline or are separated apart in the central portion of the core. The method for manufacturing a multi-layer absorbent core, according to claim 1, wherein said raster section contains first and second strips of the complete model, each having a repetitive hourglass shape, said first and second second strips of the complete model being superimposed on each other along a common line corresponding to an edge of said hourglass model, such that one of said strips of the complete model is forward of the other strip of the complete model by a half cycle , wherein said strips of the partial model are superposed in superposition with one of said strips of the complete model and the other strip of the complete model is superimposed in superposition with said strips of the partial model to form a continuous multilayer composite strip containing a strip of the complete model as a top layer, one or more intermediate layers of said partial model strips, and a strip of the comp model It is like a lower layer, wherein said strips of the partial model are placed in superposition with said first strip of the complete model such that said strips of the partial model overlap or are aligned in the same plane such that the opposite edges of the lateral edges of said Partial patterned strips along the midline or separated apart in the central portion of the core. The method for manufacturing a multi-layer absorbent core, according to claim 2 or 3, wherein said weft sections are transported under said first horizontal roller, and said first cut-away side part is twisted 180 ° and transported over said second horizontal roller such that the path of said first cut out side piece is perpendicular to the horizontal axis of said second horizontal roller, and said first cut side piece is further conveyed under said third horizontal roller, wherein the top surface of said first side piece cut out before being twisted is overlapped in overlap with said at least one strip of the complete model, said at least one strip of the complete model and said second side piece cut away being transported under said third horizontal roller, and wherein said second cut out side piece is it twists 180 ° and is transported on said fourth horizontal roller such that The path of said second cut-away side piece is perpendicular to the horizontal axis of said fourth horizontal roll, and said second cut-away side piece is further conveyed under said fifth horizontal roll, wherein the top surface of said second side piece is cut before being twisted superposed with said at least one strip of the complete model, said strip of the complete model having said first lateral piece trimmed overlapped above, being simultaneously transported under said fifth roller. The method for manufacturing a multi-layer absorbent core, according to claim 1, or the multi-layer absorbent core of claim 5, wherein the length of the front ear section is measured from the front edge of the ear From the front of the nucleus to the midpoint through the transition between the front core ear and the core crotch, the length of the crotch section is measured from the midpoint of the transition between the front core and the crotch of the core towards the midpoint of the transition between the core crotch and the posterior ear of the nucleus, and the length of the posterior nucleus ear is measured from the midpoint of the transition between the crotch of the nucleus and the posterior ear of the nucleus towards the end of the posterior ear of the nucleus; the transition between the ears of the nucleus and the crotch being symmetrical.