MXPA02002278A

MXPA02002278A - Soft, absorbent material for use in absorbent articles and process for making the same.

Info

Publication number: MXPA02002278A
Application number: MXPA02002278A
Authority: MX
Inventors: Rangachari Krishnakumar
Original assignee: Rayonier Prod & Fncl Serv Co
Priority date: 1999-09-03
Filing date: 2000-08-15
Publication date: 2002-07-30
Also published as: JP2003508647A; IL148199A0; IN2002MU00212A; CN1545992A; BR0014164A; CN1177090C; EP1268914A1; CN1387592A; WO2001018302A1; AU6908700A; TR200200537T2; CA2384508A1

Abstract

An absorbent material (20, 300, 400, 520) is provided with improved characteristics. A process is provided for making the absorbent material. A web is formed with at least one layer of absorbent material, and it may include a mixture of cellulosic fibers (32, 532) and superabsorbent material (40, 540). The moisture content of the web is increased so as to increase the web density. Then, the web is compacted at an elevated temperature to further increase the web density and preferably to also effect hydrogen bonding within the web. In one embodiment a tissue layer (22, 522) is provided, is wetted with water, and is bonded to the layer of absorbent material.

Description

SOFT ABSORBENT MATERIAL FOR USE IN ABSORBING ITEMS AND PROCESS TO MAKE THE SAME TECHNICAL FIELD. This invention relates to absorbent materials and even process for making absorbent materials to be used as absorbent cores in articles such as disposable diapers, feminine hygiene products and incontinence devices. More particularly, the present invention relates to Improved absorbent materials that are soft, resistant, high density materials with superior absorption properties 15 BACKGROUND OF THE INVENTION AND MORE TECHNICAL PROBLEMS POSED BY THE TECHNIQUE.

Disposable absorbent articles such as diapers, feminine hygiene products, incontinence devices for adults and the like have found wide acceptance. To function efficiently, such absorbent articles must rapidly absorb body fluids, distribute those fluids within and through the absorbent article and must be able to retain those body fluids with sufficient energy to dry the 25 body surface when placed under loads. In addition, the You mm? If:,., K, ... k, absorbent article must be sufficiently soft and flexible to comfortably conform to body surfaces and provide a tight fit for less spillage. While the design of the individual absorbent articles varies depending on the use, there are certain elements or components common to said articles. The absorbent article contains a liquid-permeable top cover or facing layer, the confronting layer of which is designed to be in contact with a body surface. The confronting layer is made of a material that allows the transfer of fluids substantially unimpeded from the body within the core of the article. The confronting layer must not absorb the fluid per se and, therefore, must remain dry. The article further contains a liquid impermeable back cover or back cover placed on the outer surface of the article and which layer is designed to prevent fluid spillage out of the article. Positioned between the confronting layer and the back layer is an absorbent member referred to in the art as an absorbent core or panel. The function of the absorbent core is to absorb and retain the bodily fluids that enter the absorbent article through the confronting layer. Due to the origin of the body fluids that is frequently located, it is desirable to provide means to distribute the fluid through the dimensions of the absorbent core to make full use of all available absorbent material. This is commonly accomplished either % * - - * "#»,%. .- *,. i • I providing a distribution means placed between the confronting layer and the absorbent core and / or altering the composition of the absorbent core by itself. The fluid can be distributed to different portions of the absorbent core by means of a transition layer, transition cover or acquisition layer placed between the confronting layer and the core. Due to the proximity of said acquisition layer to the user's body surface, the acquisition layer should not be formed from material that retains large amounts of fluid. The purpose of the acquisition layer is to facilitate the lateral distribution of the fluid and also to rapidly transfer and distribute the fluid to the absorbent core. The absorbent core is typically formulated from a pulp fiber matrix of cellulose wood which is capable of absorbing large amounts of fluid. The absorbent cores can be designed in a variety of ways to improve fluid absorption and retention properties. As an example, the fluid retention characteristics of the absorbent cores can be greatly improved by placing super-absorbent materials between the wood pulp fibers. Super absorbent materials are well known in the art as water insoluble absorbent polymer compositions which are capable of absorbing large amounts of fluid relative to their weight and forming hydrogels upon absorption. The absorbent articles lxk, A > £. which contain combinations or blends of pulp and super absorbent are well known in the art. The distribution of super absorbers within an absorbent core can be uniform or non-uniform. By way of example, that portion of an absorbent core near the back layer (further away from the user) can be formulated to have higher levels of super absorbent compared to those portions of the core near the confronting or acquisition layer. By way of further example, that portion of the core closest to the fluid entry site (e.g., the acquisition zone) can be formulated to transport (interlock) the fluid within the surrounding portions of the core (e.g. storage) . In addition to combining the pulp with super-absorbent material, a variety of other means to improve pulp characteristics have been described. For example, wood pulp boards can be more easily defibrated using chemical debonding agents (see for example, United States Patent No. 3,930,933). In addition, wood pulp cellulose fibers can be dried instantaneously prior to incorporation into a composite weft absorbent material (see for example, UK Patent Application G B 2272916A published June 1, 1994). In addition, individualized cellulose fibers of wood pulp can be interlaced (see, for example, US Pat.

North America Nos. 4, 822,453; 4, 888, 093; 5, 190, 563; and 5, 252, 275). All these records have the disadvantage of requiring the wood pulp manufacturer to execute expensive and time-consuming products during the preparation stages of the wood pulp. Therefore, the use of these stages results in substantial increases in the cost of wood pulp. Although all the treatment steps described above have been reported to improve the characteristics of the pulp for use as absorbent cores, there are certain disadvantages associated with such treatments. By way of example, the manufacturer of the end-use absorbent article (e.g., feminine hygiene product or diaper) commonly provides wood pulp in the form of a sheet from a wood pulp manufacturer. The manufacturer of the end-use article must then fluff the fibers into the wood pulp sheet to separate the individual fibers bound into that pulp sheet. Typically, the pulp has a low moisture content, and this causes the individual fibers to be relatively brittle, resulting in fine dust due to the breakage of the fiber during the foaming operations. If the pulp manufacturer executes said swelling before shipment to the manufacturer of the absorbent article, the transportation costs of the pulp increase. At least one pulp manufacturer has attempted to solve this problem by producing dried pulp instantaneously without chemical bonding agents in a narrow range based on weights and density of the pulp (see US Pat. No. 5,262,005) . However, even with this process, the manufacturer of the absorbent article must still process the pulp after the purchase. There have been numerous attempts by manufacturers of absorbent materials to produce soft, resistant, highly absorbent core materials. U.S. Patent No. 4,610,678 discloses an air-laid material containing hydrophilic fibers and super-absorbent material, wherein the material is laid to air in a dry and compacted state without the use of any of the binding agents added. Such a material, however, has a low integrity and experiences the shaking or loss of substantial amounts of the super-absorbent material. In the Patent of the United States of North America No. 5, 516, 569 describes that shaking of the absorbent material that can be reduced in absorbents laid to the air by adding significant amounts of water to the material during the process of laying in the air. However, the resulting material is rigid, or of low density and has a higher water content (of more than about 15% by weight). U.S. Patent No. 5, 547, 541 discloses that high density air-laid materials containing hydrophobic fibers and super-absorbent material can be made by adding densification agents to the material. However, the use of such agents increases the production cost of the material. t-A t 1, U.S. Patent No. 5, 562, 645 describes low density absorbent materials (density less than 0.25 g / cc). The use of such bulky, low density materials increases the cost of transportation and handling. U.S. Patent No. 5,635,239 describes an absorbent material that contains two complex forming agents that interact when wetted to form a complex. The complexing agents are polymeric olefins. European Patent Application No. EP 0763364 A2 describes the absorbent material containing cationic and anionic binders which serve to retain the superabsorbent material within the material. The use of such agents and agglutinators increases the cost of processing the absorbent material and poses a potential environmental risk. The Patent of the United States of North America No. 2,955,641 and U.S. Patent No. 5,693,162 describe (1) the application of steam to absorbent material to increase the moisture content of the absorbent material, and (2) compress the absorbent material. U.S. Patent No. 5,692,162 also describes the use of hot calendering rolls (which may be molded) to form a densified structure, and the use of thermoplastic and thermosetting resins suitable for thermal bonds. t.j. i ^.,. i ,. ±%,.

US Pat. No. 5,919,178 discloses a process for producing an absorbent structure having an intermediate layer containing superabsorbent material sandwiched between two absorbent layers wherein the bottom layer may be tissue paper. The patent discloses that when the tissue paper is used as the top or bottom layer, the moisture content of the tissue paper should be 20% -70% (by, for example, spraying the tissue paper with moisture immediately before calendering in a pressure line of 100-200 kg / cm and at a temperature of 120 ° C -250 ° C to compress the weft up to a density of 0 1 g / cm3 in order to produce a pulp mat of thickness of 1 mm-4 mm) However, there is still a need for the technique of an improved process for making an absorbent material that satisfies the requirements of absorbency, strength and softness necessary for use as an absorbent core in disposable absorbent articles and which also provide time and cost savings. both to the manufacturer of the pulp and to the manufacturer of the absorbent article.

BRIEF DESCRIPTION OF THE INVENTION In accordance with one aspect of the present invention, there is provided a process for making an absorbent material free of aggregate chemical binders and thermosetting bonding agents.

In one embodiment of the material, a web is formed with at least one layer of a mixture of cellulose fibers and super absorbent material. The moisture content of the web is increased to increase the density of the web. Preferably, this is affected by the addition between about 1% and about 9% moisture by weight based on the total weight of the web before the addition of moisture. Then, the web is compacted at a high temperature to increase the density of the web and to effect hydrogen bonding within the web which is left substantially free of moisture. After the web has cooled, it is preferably kept in equilibrium in an atmosphere such that the moisture content is between 2% and 8% and more preferably between 3% and 6% by weight based on the total weight of the plot with moisture. In a preferred form of the process of the invention, the moisture content of the web is increased by transporting the web through a steam region having a temperature of more than about 100 ° C, and the web is compacted between the webs of calendering wherein at least one of the rolls is heated to a surface temperature in the range of between about 70 ° C and about 200 ° C. The process of the present invention can be used to make various forms of absorbent material. One form of the absorbent material has a basis weight from about 180 g / cm2, to about 600 g / cm2, a density from -. 1 M? about 0.25 g / cc to about 0.45 g / cc. The material is laid to the air as a lower layer of pulp (or pulp and super-absorbent material placed between the pulp), an intermediate layer of pulp and super-absorbent material placed between the pulp, and a top layer of pulp. The pulp preferably has a Kappa value of less than about 100. The absorbent material includes from about 40% by weight to about 90% by weight of cellulose fibers and from about 10% by weight to about 60% by weight of super material. absorbent based on the total weight of the weft with the super-absorbent material. Said super-absorbent material has a water content of less than about 10% by weight based on the total weight of the material with the water, and a density of more than about 0.25 g / cc. With all forms of the material, it is preferred that at least some of the cellulose fibers have a relative crystallinity of less than about 65%. In another form, the absorbent material has a basis weight from about 100 g / m2 to about 500 g / m2 a density from about 0.25 g / cc to about 0.50 g / cc. Said material includes a core of cellulose fibers obtained from the pulp wherein at least part of the pulp fibers have a Kappa value of less than about 100. A carrier layer (e.g., a tissue paper layer) can be overlapped. on an external surface of core. The carrier layer is preferably crepe tissue paper. At least some of the cellulose fibers have a relative crystallinity of less than about 65%. The core contains from about 40% by weight to about 100% by weight of cellulose fibers and from about 0% by weight to about 60% by weight of super absorbent material. Preferably, the core contains from about 40% by weight to about 90% by weight of cellulose fibers and from about 10% by weight to about 10 of 60% by weight of super-absorbent material. In another form, the absorbent material has a density from about 0.25 g / cc to about 0.5 g / cc and a basis weight from about 200 g / m2 to about 500 g / m2. This material consists essentially of 15 (1) from about 60% by weight to about 90% by weight of cellulose fibers at least some of which are obtained from pulp having a Kappa value of less than about 100, wherein by at least some of the cellulose fibers have a relative crystallinity of less than about 60%; (2) 20 from about 10% by weight to about 40% by weight of per-absorbent material; and (3) a tissue paper layer comprising from about 3% by weight to about 20% by weight of the absorbent material. The tissue paper is preferably crepe tissue paper.

- ** M-M *, MMt'l »« i «.« * ,. «ar.1. t .t, j - Preferably, the material is made using cellulose fibers having a relative crystallinity preferably less than 60%. More preferably, the cellulose fibers have a relative crystallinity of less than about 50% and even more preferably a relative crystallinity of less than about 40%. At least some of the cellulose fibers are obtained from pulp having a Kappa value less than about 75, 50, 25 or 10. More preferably, the Kappa value is less than 5 or 2.5. In one form of the absorbent material, at least some of the cellulose fibers in the material are made through a process that includes the step of treating a liquid slurry of pulp at a temperature from about 15 ° C to about 60 ° C. with an aqueous alkali metal salt solution having an alkali metal salt concentration of from about 2% by weight to about 25% by weight of said solution for a period ranging from about 5 minutes to about 60 minutes. In another form of absorbent material, at least some of the cellulose fibers have been dried instantaneously. In another form of the absorbent material, the cellulose fibers are not dried instantaneously, but are processed through a hammer crusher. An especially preferred form of the absorption material made by this process of the invention has a density of At about 0.28 g / cc to about 0.40 g / cc, and a basis weight from about 180 g / m 2 to about 550 g / m 2. According to this aspect of the invention, a modification of the process for making an absorbent material includes the steps of: (A) forming a web having a layer of tissue paper on which is placed at least one absorbent layer containing cellulose fibers free of added chemical binders and thermobonded bonding agents. (B) spraying water against the weft to add between about 2% and about 9% (and preferably between about 1% and about 8%) of moisture based on the weight on the weft weight before the addition of moisture; and (C) after the step of (B), compacting the weft at an elevated temperature to further increase the density of the weft, and preferably also effecting an increase in the strength of one or more of the absorbent layers. and / or increasing the bond strength of the tissue paper to at least one absorbent layer. The sorbent material produced through the modified process can be etherised as an absorbent material which (I) is made by the process comprising the steps of: (A) forming a web having a first layer of tissue paper on which place at least one absorbent layer containing cellulose fibers free of added chemical glutinators and agents of W * í .j? : fixed thermos connection; (B) spraying water against said layer of tissue paper by adding between about 2% and about 9% (and preferably between 1% and about 8%) moisture by weight based on the weight of the weft before the addition moisture; and (C) after step (B), compacting said web at an elevated temperature to further increase the density of the web and effect the increased binding of the tissue paper to said at least one absorbent layer; and (II) having a bond strength between the tissue paper layer and an absorbent layer that exceeds a test delamination force of 3 newtons (as determined in accordance with a test set forth in detail hereinafter). A second tissue paper layer can also be attached to the side of the opposite weft of the first tissue paper layer. A preferred form of said absorbent material can be characterized as a weft having a carrier layer on which is placed at least one absorbent layer containing at least cellulose fibers free of added chemical binders and thermobonding bonding agents where the The plot has the following preferred properties: (1) a density of between about 0.25 grams per cubic centimeter and about 0.5 grams per cubic centimeter. (2) a basis weight between about 150 grams per square meter and about 600 grams per square meter; (3) a Gurley stiffness of less than about 1500 milligrams; (4) a tensile strength in the machine direction greater than about 9 newtons; and (5) a bond strength between said at least one layer of absorbent and the carrier layer exceeding a test delamination force of 3 newtons. The preferred forms of the material have superior absorbent properties. The absorbent material can be made through the process of this invention which can be used to make absorbent articles, such as a diaper, a feminine hygiene product or an incontinence device.

BRIEF DESCRIPTION OF THE DRAWINGS.

In the drawings, which form a part of the specification: Figure 1 is a simplified fragmentary perspective view of a sheet of absorbent material that can be made by the process of the present invention, Figure 2 is a fragmentary cross-sectional view very enlarged, generally taken along the plane 2-2 in Figure 1, and in Figure 2 the height or thickness of the portions of the structure illustrated have been exaggerated for ease of illustration Ii. te-t- * Í? and it should be understood that Figure 2 is not necessarily drawn to scale with respect to the thicknesses of the different portions; Figure 3 is a diagrammatic view illustrating a def-process form of the present invention; Figure 4 is a view similar to Figure 2, although Figure 4 illustrates another form of the absorbent material; Figure 5 is a view similar to Figure 4, although Figure 5 illustrates another form of an absorbent material; Figure 6 is a view similar to Figure 2, although Figure 6 illustrates another form of the absorbent material, Figure 7 is a view similar to Figure 3, but Figure 7 illustrates another form of the process of the present invention used for making the absorbent material illustrated in Figure 6 with an increased bond strength between a tissue paper layer and the remainder of the absorbent core portion; Figure 8 is a fragmentary, front perspective, simplified view of a tension / compression test machine; Figure 9 is a fragmentary, perspective view of the upper platen used in the test machine shown in Figure 8; Figure 10 is a perspective view of a portion of a form of the absorbent material of the present invention at which joins a two-sided tape length; Figure 11 is a simplified, partially diagrammatic perspective view of the portion of absorbent material of the - a i á - > * figure 10 shown in a hydraulic press that uses a circular die to cut a circular test sample; Figure 12 is a perspective view of a circular cut test sample of the absorbent material; Figure 13 is a perspective view of the die cut sample mounted to the upper stage before the upper stage is mounted to the test machine; Fig. 14 is a fragmentary perspective view of the lower platen of the test machine showing a strip of the two-sided tape secured to the lower platen; Fig. 15 is a fragmentary side elevational view of the test machine in operation to initially compress the test sample; Figure 16 is a fragmentary view si mular to Figure 14; although Figure 16 shows a later stage during the test where the test machine has exerted tension on the test sample and has caused the test sample to be extracted; and Figure 17 is a common graph or graph of the load versus extension during the test.

DETAILED DESCRIPTION The process of the present invention provides an improved absorbent material that is partially suitable for use as cores in absorbent articles such as diapers, feminine hygiene products, incontinence devices and the like. The absorbent material can also be used as an absorbent core in any device used to absorb body exudates (e.g., urine, breast milk, blood, serum). Thus, the absorbent material can be incorporated into breast pads for nursing mothers or used as an absorbent material in surgical bandages (eg, towels) or dressings. The preferred form of the absorbent material includes a combination of cellulose fiber and super absorbent blend placed between the fibers of that pulp. The absorbent material has a unique combination of flexibility, strength and absorbency characteristics that make it particularly suitable for use in absorbent articles. The absorbent material can be used directly by a manufacturer of the absorbent article without the need for any additional processing by that manufacturer other than cutting or folding the absorbent material to the size and shape desired for the absorbent article. The process of the present invention can be used to make an absorbent material that is soft, that is thin, and that it has a relatively high density. Additionally, the material can have improved absorption properties, and firmly trap the super-absorbent material in the fiber network without the use of chemicals, binders, adhesives, thermoplastic resins, thermoplastic binder fibers, *. - * «1 & f l »complex formation or similar The absorbent material has sufficient integrity (strength) to be processed into conventional disposable manufacturing equipment if n break means the fiber. In accordance with one aspect of the present invention, the process of the invention can provide an absorbent material containing from about 40% by weight to about 100% by weight of cellulose fibers based on the total weight of the absorbent material, from about 0. % by weight up to about 60% by weight of superabsorbent material based on the total weight of the absorbent material, and about 10% by weight or less of water based on the total weight of the absorbent material. With reference to the composition of an existing material containing a substance, the phrase "weight percentage" as used herein represents the weight of the substance divided by the total combined weight of the substance and the material (as determined under environmental conditions) and multiplied by 100 By way of example, the absorbent material containing 10% by weight of super-absorbent material means that there are 10 grams of super-absorbent material in a 100 gram sample containing the absorbent material and the material super absorbent. On the other hand, when referred to herein by adding a certain percentage by weight of moisture or water to a material . - & > . * Existing, then the percentage by weight of water that is added is based on the weight of material before the addition of water. The cellulose fibers that can be used in the process of the present invention are well known in the art and include wood pulp, cotton, flax and peat. The wood pulp is preferred. The pulps can be obtained from mechanical or chemomechanical materials, from sulfite, from cellulose to sulphate, from pulp rejection materials, pulps of organic solvent, etc. Coniferous wood and hardwood species are useful. Coniferous wood pulps are preferred. It is not necessary to create cellulose fibers with chemical separation agents, interlacing agents and the like for use in the absorbent material. As described above, with the preferred cellulose fiber for the present material is wood pulp. The wood pulp that was prepared using a process that reduces the lignin content of the wood is preferred. Preferably, the lignin content of the pulp is less than about 16%. More preferably, the lignin content is less than about 10%, even more preferably, the lignin content is less than about 5%. More preferably, the lignin content is less than about 1%. As is known in the art, the lignin content is calculated from the Kappa value of the pulp. The Kappa value is determined using a well-known standard test procedure (TAPPI test 265-cm 85). The Kappa value of a variety of pulps was measured and the lignin content was calculated using the TAPPI 265-cm 85 test. The peat was found to have a Kappa value of about 104 and a lignin content of about 1 3.5%. It was found that the CTMP pulp has a Kappa value of approximately 123 and a lignin content of approximately 16%. The pulp prepared from coniferous wood using either sulfate cellulose or sulfite methods has a Kappa value of about 1.1 and a lignin content of about 0.15%. When the last pulp was treated using a cold caustic extraction method, the Kappa value was found to be about 0.97 and the lignin content about 0.12%. For use in the process of the present invention, the cellulose fibers are obtained preferably from wood pulp having a Kappa value of less than about 100. More preferable, the Kappa value is less than about 75, 50, 25 or 10. More preferably, the Kappa value is less than about 2 5 There are other characteristics of the wood pulp which make it particularly suitable for use in an absorbent material . Cellulose in most wood pulps has a high relative crystallinity (greater than about 65%). In a current material, the use of wood pulp with a relative crystallinity of less than about 65% is preferred. Most preferably, the relative crystallinity is U »Íi..j. "I: go.tm..Í less than about 50%. More preferably, the relative crystallinity is less than about 40%. Likewise, pulps having an increased fiber ripple value are preferred. Means for treating pulps to optimize those characteristics are well known in the art. By way of example, the treatment of wood pulp with liquid ammonia is known to decrease the relative crystallinity and to increase the fiber ripple value. Immediate drying is known to increase the rippling value of the pulp fiber and to decrease the crystallinity. The cold caustic treatment of the pulp also increases the ripple of the fiber and decreases the relative crystallinity. Chemical entanglement is known to decrease relative crystallinity. It is preferred that the cellulose fibers used to make the absorbent material through the process of this invention are obtained at least in part using cold caustic treatment or flash drying. A description of the cold caustic extraction process can be found in United States of America Patent Application Serial No. 08 / 370,571, of common possession, filed on January 18, 1995, the application of which is an application for follow in part of the United States of America Patent Application Serial Number 08 / 184,377, filed January 21, 1994, and currently abandoned. The descriptions of those two Patent Applications of the States United States of America are incorporated in their entirety hereby by reference thereto. Briefly, a caustic treatment is commonly carried out at a temperature of less than about 60 ° C, but preferably at a temperature of less than 50 ° C, and more preferably at a temperature between about 10 ° C and about 100 ° C. 40 ° C. A preferred alkali metal salt solution is a freshly formed sodium hydroxide solution or as a by-product of solution in a pulp or paper milling operation, for example, white semi-aqueous liquor, oxidized white liquor and the like. The different alkali metals such as ammonium hydroxide and potassium hydroxide and the like can be used. However, from a cost point of view, the preferred salt is sodium hydroxide. The concentration of alkali metal salts is typically on a scale from about 2 to about 25% by weight of the solution, and preferably from about 6 to about 18% by weight. Pulps for high range rapid absorption applications are preferably treated with alkali metal salt concentrations from about 10 to about 18% by weight. As is known in the art, instant drying is a method for drying the pulp in which the pulp is partially dehydrated, fiberized and fed into a stream of hot air which causes the moisture contained in the pulp to be dried immediately. Briefly, the pulp, initially at a ll t "~» - * - * »&» * - '•. .- * ..- < --- .. * »...... ..» - ».... - ^ ^. ii, i't.J. consistency of 30-45% (containing 55-70% water), is transported directly into a sponge (eg, a disc refiner) where the mechanical action is used to Fiberising (breaking and separating) and dispersing the fibers for the instant drying system Once discharged from the sponge device, the fibrillated pulp is fed into an instant drying system.The drying system consists of two stages, each of which consists of two drying towers.The fiber is transported through the drying towers by high hot air speeds.The temperature of the inlet air to the first stage is about 240-260 ° C, while the Inlet air temperature for the second stage is approximately 100-120 ° C. After each stage of drying, the pulp and the hot air are transported inside a cyclone separator, where the hot air, which now contains the moisture evaporated from the pulp, is emptied vertically. In a common small-scale system, the exhaust temperatures for the first stage, in this case, are approximately 100-120 ° C, and the exhaust temperatures for the second stage are approximately 90-100 ° C. At the same time, a material handling fan extracts the pulp fibers through the cone of the cyclone and over the next part of the system. Finally, after the second stage of the cyclone separator, the dried pulp is passed through a cooling stage consisting of a cooling fan that transports ambient air, and is passed through the a final cooling cyclone separator. The dwell time for the entire system, including both drying steps, cyclone separation and cooling, is approximately 30-60 seconds at a feed rate used (1.5 kg of dry material per minute which is a range of typical speed of a small-scale machine). Conventional larger-scale instant drying systems commonly have higher feed rates. A case for producing dried fiber instantaneously using the type of system described above is the production of the I fiber groups located in the final product. The groups of fibers are formed during the fibrization of the pulp through mechanical action within the sponging device. The previous system uses a disk refiner consisting of two circular plates slotted in a fixed space width, in this case 4 mm. One plate is in a fixed position while the other plate is rotated at high speeds. The pulp is fed into the space between the two plates and the rotation of the plate results in the separation of fibers along the slots. Unfortunately, since that the pulp is fibrized, part of the fibers tend to become entangled with each other, forming small groups that consist of several individual fibers. Since these matted fibers are dried instantaneously and the moisture is removed, the entanglements harden and stretch to form small groups of fiber located through the dried pulp instantaneously. The Í t, .i ^. The presence of large numbers of these fiber groups located within the final air-laid products produced using the dried pulp can have a deleterious effect on the characteristics and physical performance of the product. The number of localized fiber groups can be substantially reduced using cold caustic extracted pulp. According to a process of the aspect of the present invention (as described below), an absorbent material is made to contain a super-absorbent material. Super absorbent materials are well known in the art. As used herein, the term "super absorbent material" means a polymeric material substantially insoluble in water capable of absorbing large amounts of fluid relative to its weight. The absorbent material may be in the form of particulate material, flake fibers and the like. Exemplary particle forms include granules, pulverized particles, aggregate spheres and agglomerates. Illustrative and preferred superabsorbent materials include crosslinked polyacrylic acid salts such as sodium polyacrylate. Absorbent materials are commercially available (for example from Stockhausen GmbH, Krefeld, Germany). A preferred form of the absorbent material contains from about 0 to about 60% by weight of superabsorbent material, and more preferably from about 20 to about 60% by weight of superabsorbent material. Bliss TO .

Preferred form of absorbent material has about 40 to about 100% by weight of cellulose fibers and, more preferably about 40 to about 80% is weight of cellulose fibers. According to yet another aspect of the present invention, a unique process for making a weft of absorbent material is provided, although the process may be implemented without including a superabsorbent material in all parts of the weft or even in any part of the weft. the plot.

FORMS OF ABSORBENT MATERIAL.

The absorbent material made by the process of the present invention preferably has a moisture content of less than about 10% of the total weight of the absorbent material to discourage bacterial growth. Likewise, the material is free of added chemical binders and heat-set bonding agents. Figure 1 illustrates a form of an absorbent material that can be made by the process of the present invention. The absorbent material is designated in Figure 1 generally by reference numeral 20. The material 20 is commonly made through the process of the present invention in a relatively broad sheet that can be provided in sheet form or inl-.í-t-.il ¿a f i ,, K. »•» & ,1 ?. í .i t - a large roll towards a manufacturer of absorbent articles. A typical thickness of the material is between 0.5 mm and 2.5 mm. Figure 2 illustrates a cross section of the material. The regions of various thicknesses in the material 20 illustrated in Figure 2 are not necessarily to scale and may in some respects be exaggerated for purposes of clarity and ease of illustration. The absorbent material 20 illustrated in Figure 2 includes an optional carrier layer. The carrier layer 22 may be, for example, a spunblown, spin-blown non-woven material consisting of natural or synthetic fibers. Another preferred material that can be used for the carrier layer is tissue paper. Tissue paper materials suitable for common use in the carrier layer of the absorbent products are well known to those of ordinary skill in the art. Preferably said tissue paper is made of a bleached wood pulp and has an air permeability of approximately 273-300 CFM (cubic feet per minute). The tensile strength of the tissue paper is such that it retains integrity during the formation and calendering of the absorbent material. The tensile strengths MD (machine direction) and CD (transverse direction), expressed in newtons / meter, are approximately 100-130 and 40-160 respectively. Tissue paper for use in airborne absorbent materials is commercially available (e.g., from Cellu Tissue Corporation, 2 Forbes Street, East Hartford, CT 06108, USA).

United States, and Duni AB, Switzerland). In a preferred embodiment, the tissue paper is crepe tissue paper having a sufficient number of fold-per-inch to allow an elongation in the machine direction of between 20 and 35% (as determined by the SCAN P44 test method: 81). The absorbent material 20 on the tissue paper layer 22 typically includes one or more different layers or layers. The thickness of each layer and the number of layers can vary. Figure 2 illustrates the currently considered commercial form of the material for a particular application in female hygiene tubes. The absorbent material 20 illustrated in Figure 2 includes a deeper or first layer 24, a second layer 26, a third layer 28, and a fourth or upper layer 30. In the form of the absorbent material 20 illustrated in Figure 2 , the layers 24, 26 and 28 together define an absorbent core portion 36. The upper layer 30, which is optional, is typically characterized as a transition layer, acquisition layer or transfer layer described in detail below. The layers 24, 26, 28 and 30 are referred to as layers or layers because the material forming said layers or layers is initially laid out in the process of the present invention as layers or layers separated on the upper part of the layer. another as explained in detail below. However, after the completion of the process of making the absorbent material, the layers or strata are part of a unitary or integral structure.

Typically, there is little distinguishable visual difference between the different layers. If someone tries to separate the absorbent material in the layers or strata by which it was initially laid in the manufacturing process, it will be found that the finished absorbent material does not easily separate or delaminate into the specifically identifiable layers or strata corresponding to the layers or strata spread during the production process. Preferably, when a carrier layer, such as the tissue paper layer 22, is used, the tissue paper is slightly embedded within the lower layer 24 of the absorbent core portion 36, and this may be effected during processing with a knotty roll. or a roll of linen (or other embedded) roll calender as described in more detail below. Preferably, if a knotty or linen calendering roll is used, the knotty or linen surface of the roll has a depth of more than 5% of the thickness of the carrier layer (tissue paper layer). Typically, an absorbent article manufacturer would add a confronting layer, top layer or cover material (not shown) on the transition layer 30, and said confronting layer makes contact with the skin of the person using the article. The upper transition layer 30 functions as an acquisition layer for receiving liquid (eg menstrual discharges or urine) in the first moments of discharge through the confronting layer. This transition layer 30 collects the liquid from the confronting layer of the absorbent article very quickly and To L? it distributes the liquid to the absorbent core 36. The transition layer 30 maintains a distance between the confronting layer and the core 36 to inhibit the liquid from moving towards the core 36 towards the wearer's skin of the absorbent article. The transition layer 30 facilitates the lateral distribution of the liquid, especially during the second and subsequent discharges of the liquid within the absorbent article. In an alternative embodiment, the transition layer 30 may be omitted. Layers 24, 26 and 28 include pulp fibers 32 having a common average length of approximately 2.40 mm. Preferably, at least some of the fiber pulps 32 are produced by the cold caustic extraction process described above. This includes treating a liquid suspension of cellulose fibers containing pulp at a temperature from about 15 ° C to about 60 ° C with an aqueous alkali metal salt solution having an alkali metal salt concentration of about 2% by weight to about 25% by weight of the solution during a period ranging from about 5 to about 60 minutes. The cellulose fibers of treated pulp are dried instantaneously or processed through a hammer crusher. The absorbent core portion layers 24, 26 and 28 each preferably include a super absorbent material of the previously described type and which is preferably provided in the form of granules or super absorbent particles. The upper transition layer 30 is free of superabsorbent particles. If the transition layer 30 is omitted, then the top layer of the remaining absorbent core portion layers (e.g., top layer of the absorbent core portion 28) would preferably be free of superabsorbent particles. In a preferred form of the absorbent material 20 which is illustrated in Figure 2 having a transition layer 30, each of the layers 24, 26 and 28 of the absorbent core portion 36 includes super-absorbent particles. If desired, the layers containing pulp and super-absorbent material may be laid out as a homogeneous combination or as a heterogeneous combination wherein the level of the super-absorbent material varies with proximity to the bottom (ie, the lower carrier layer 22). In modified forms of the super-absorbent materials, the concentration (weight percent) of the super-absorbent material in each layer 24, 26 and 28 may vary as can the nature or type of the particular super-absorbent material. Also, the super absorbent material could be limited to only one or some of the layers that make up the absorbent core pore portion 36. Preferably, the total base weight of the pulp and the super absorbent material in the lower layer 24 it is typically between about 50 and about 270 g / m2. The total basis weight of layer 26 is typically between about 50 and about 270 g / m2. The total basis weight of layer 28 is typically between about 20 and about 270 g / m2. The basis weight , total kl of top layer 30 would commonly be between about 0 and about 50 g / m2. The preferred thickness of the upper transition layer 30 is in the range of between about 0.20 mm and about 0.50 mm. The thickness of each of the core layers 24, 26 and 28 are in the range of between about 0.2 mm and about 0.9 mm. In some applications, the thickness of each of the core layers may be as low as 0.44 mm or less. The average density of the absorbent material 20 preferably varies between 0.25 and 0.5 g / cm3. The moisture content of the absorbent material 20 after equilibration with the ambient atmosphere is preferably less than about 10% (by weight of the total weight of the material), and more preferably is less than about 8%, and is preferably located in the range of between approximately 3% and approximately 8%.

PRODUCTION AND APPARATUS PROCESS: PRI MERA MODALITY.

The absorbent materials described above can be made with the process of the present invention. A first embodiment of the process of the present invention is illustrated diagrammatically in Figure 3. The illustrated process employs a cable, screen or endless band 60 on which the components of the absorbent material are deposited.

The process allows the optional incorporation of a carrier layer in the absorbent material (e.g., tissue paper layer 22 in the absorbent material 20 described above with reference to Figure 2). For this purpose, a tissue paper web 62 is unwound from a tissue paper web 64 and directed over the endless mesh 60. In the preferred form of the process, the series includes a first forming head 71, a second forming head. 72, a third forming head 73 and a fourth forming head 74. A greater or lesser number of forming heads can be provided depending on how many layers of material are to be laid. The cellulose fibers, some of which are in the form of the cold caustic extracted pulp fibers described above, are processed using a hammer crusher (not shown) to individualize the fibers. The individualized fibers are combined with super absorbent material, granules or particles in a separate combination system supplied by each forming head. The forming head 71 is connected to a combiner system 81, the forming head 72 is connected to a combiner system 82 and the forming head 73 is connected to a combiner system 83. In some systems, the pulp fibers and granules or super particles Absorbents are mixed and transported pneumatically inside the forming heads. In other systems, pulp fibers and granules or super-absorbent particles are transported separately to the heads & fc I-.

Formers and combine together in the forming heads. The chemical bonding agents and the fixed bonding agents are not added during the processing of the fiber or during the combination of the fibers with the super-absorbent material. The forming head 74 is connected to a combiner system 84, and the forming head 74 provides the pulp fibers or other components towards the upper transition layer 30. The upper layer 30 does not have super-absorbent material as previously explained with reference to the absorbent material 20 illustrated in Figure 2. The combination and distribution of the materials can be controlled separately for each forming head. For example, some systems, controlled air circulation and finned agitators in each combiner system produce substantially uniform mixing and distribution (of the pulp and super-absorbent particles for combinator systems 81, 82 and 83 and of the fibers). pulp alone for the combiner system 84). The super absorbent particles can be combined completely or homogeneously through the entire absorbent core portion of the structure that is produced, or contained only in a specific layer or layers by distributing the absorbent particles to selected forming heads. If desired, the super-absorbent particles can be separately discharged from separate forming heads 91, 92 and 93 as individual layers of 100% super-absorbent. In tA4s§? ? * 4.11 * 1. & t * m ~ mi J-l l ln such optional configuration, the super-absorbent particle forming head 91 is located between the forming heads 71 and 72, the super-absorbent particle forming head 92 is located between the forming heads 72 and 73 and the superabsorbent particle forming head 93 is located between the forming heads 73 and 74. If the separate superabsorbent forming heads 91, 92, 93 are used, then the additional super absorbent particles could still be combined in the combiner systems 81, 82 and 83. Alternatively, only the pulp fibers could exclusively be transported to and through the combiner system 81, 82 and 83 and the forming heads 71, 72. and 73 respectively, when the super absorbent material is discharged from the forming heads 91, 92 and 93. The material from each forming head is deposited by vacuum on the tissue paper web or carrier layer 62 (or directly on the endless mesh 60). ) to form a layered absorbent web. The layered absorbent web is transported with the aid of a conventional vacuum transfer device 100 from the end of the endless mesh 60 to a moisture addition apparatus 1 10. The system could alternatively be designed to remove the transfer device 100. Apparatus 1 10 typically includes a housing or enclosure and suitable means for supplying moisture and / or controlling humidity in the enclosure around the layered web. In a i.lr.

As contemplated, the moisture may be supplied in the form of low pressure steam from the nozzle on the upper and lower sides of the layered web, or only from the bottom side. In another contemplated embodiment, moisture is supplied in the form of low pressure steam through a nozzle 14 on the weft. In the part of the frame opposite the nozzle 14, the apparatus may include a steam suction chamber 1 18. Other means may be provided in the device 1 10 to establish a desired atmosphere around the layered web where the content of moisture in the atmosphere is controlled. In a preferred embodiment currently contemplated of the process of the present invention, moisture is provided to the device 1 10 in the form of steam at a pressure of between about 0.0703Kg / cm2 and about 1.46Kg / cm2 and at a temperature of between about 100. ° C and around 125 ° C. The steam is preferably maintained on one side of the screen at a temperature of at least about 100 ° C. Steam flows in and through the weft pattern and increases the moisture content of the weft. According to a preferred form of the first embodiment of the process of the present invention, the moisture content of the weft, immediately after being subjected to steam, is less than about 10 percent, preferably less than about 9 percent by weight, of the total weight of the plot. There is no thermal bonding of the pulp fibers, however, it is currently considered that the addition of the t ^ t -i. .k n. to. ??.3. riaü? - Humidity increases the density of the weft and facilitates the establishment of hydrogen bonding of the pulp fibers with each other, as well as from the tissue paper layer to the pulp fibers, and this increases the strength or integrity of the material absorbent finished. As the weft in wet layers comes out of the moisture addition device 1 10, it is compressed or compacted between a pair of heated calendering rolls, upper roller 121 and lower roller 122. This increases the density of the weft. The preferred shape when the top layer is free of super absorbent material, the super absorbent material in the underlying portion of the web does not contact and adhere to the heated top calender roll. The upper roller 121 is typically a steel roller and the lower roller 122 is typically a flexible roller having a hardness of approximately 85 SH D. Although both rolls may be uniform, in the preferred process, the upper roller 121 has a uniform surface and the lower roller 122 has an oiled surface. The functions of the knurled surface for embedding the paper layer 62, or another type of carrier layer, within the bottom of the absorbent material. Preferably, the knurled surface has a depth greater than 5% of the thickness of the carrier layer. Each roller 121 and 122 are heated to a temperature between about 70 ° C and about 200 ° C, Preference of approximately 150 ° C. The weight of the upper roller 121 rests on the layered web. The additional force may be provided with conventional hydraulic actuators (not shown) acting on the axis of the roller 121. In the form of the invention, the web is compacted between the rollers 121 and 122 under a load of between about 28 and about 400 newtons per one millimeter cross-sectional width (2856-40769.4 Kg. force-meter cross-sectional width). It is now considered that heated compaction increases the density of the weft and effects the establishment of hydrogen bonding of the pulp fibers with each other, as well as from the tissue paper layer to the pulp fibers, to increase the strength and integrity of the finished absorbent material. This provides a finished product with exceptional resistance to the shaking of the super absorbent material. When leaving the calendering rollers, the plot contains very little moisture. The compressed and densified web is wound inside a roller 130 using conventional winding equipment. The moisture content of the weft will commonly increase as the weave reaches equilibrium with the ambient atmosphere, although it is desirable that the moisture content is not too high, preferably between about 3% and 8% of the total weight of the weft . The processing line is preferably moved at a linear velocity of approximately? 5 meters per second until 5. 0 meters per second approximately. The dwell time of the web within the humidity addition device 10 is preferably between about 0.1 and about 1.0 seconds.

The presently contemplated preferred form of the first embodiment of the process of the present invention employs calendering rollers 121 and 122 to apply heat and pressure to the weft. However, it will be appreciated that the present invention also contemplates the use of other means for compacting and applying heat to the weft. For example, a pair of movable heated platens can be used in place of the calendering rolls. Alternatively, opposite heated, endless band assemblies can be used to compact and heat the weft in place of the calendering rolls. Finally, instrumentation to compact or densify the weft can be separated from the instrumentation to apply heat to the weft. However, currently it seems to be more practical to combine such instrumentation, as with heated calendering rollers.

CHARACTERISTICS OF ABSORBENT MATERIAL An individual layer or multiple layer absorbent material made by the first embodiment of the process of the present invention is of a relatively high density and has a composite density that is preferably greater than about 0.25 g / cc. In the preferred embodiments, the absorbent material Í? Iií? J, J. • tbál? t-fc-i ,. It has a compound density on the scale from about 0.25 g / cc to about 0.50 g / cc. More preferably, the density is from about 0.25 g / cc to about 0.45 g / cc. More preferably, the density is from about 0.28 g / cc to about 0.40 g / cc. A high density absorbent material made through the process of the present invention containing the superabsorbent material is surprisingly and unexpectedly adaptable. The term "adaptive" is used herein to describe those characteristics of softness, flexibility and bending ability. A related feature is Gurley stiffness that measures the stiffness of absorbent materials. The higher the rigidity value, the more rigid and inflexible Gurley is the material. The inverse of the Gurley stiffness expressed as inverse grams (g * 1), is therefore a measure of the softness, bending capacity and flexibility of the absorbent materials. The adaptability is defined and expressed as the inverse of the Gurley stiffness and has the g'X units. The high density absorbent material is resistant regardless of its adaptability. The pad integrity is a well-known characterization of the strength of the absorbent material. The high density absorbent material made through the process of the present invention has good strength (high pad integrity). An absorbent material can be prepared through the process , &A, E * A of the present invention over a wide range of basis weights without adversely affecting its softness or strength. Thus, the absorbent material can have a basis weight in the range from about 50 g / m2 to about 800 g / m2 and above. In a preferred form the base weights range from about 100 g / m2 to about 500 g / m2, and more preferably from about 100 g / m2 to about 250 g / m2 or from about 300 g / m2 to 500 g / m2. m 'The process of the present invention can be used to make an absorbent material having superior absorbent properties when compared to existing materials. The absorbent properties of the materials can be evaluated in a variety of ways. Of particular relevance to manufacturers of absorbent articles is the ability of the material to absorb large amounts of fluid against a load and to distribute that fluid away from the point of deposition or entry of the fluid. Packaging is the ability of an absorbent material to direct the fluid away from the point of fluid entry and distribute that fluid throughout the material. An absorbent material made through the process of this invention has good packaging properties. The unique combination of strength, absorbent capacity and adaptability of the absorbent material that can be made through the process of the present invention has significant advantages t. »i. for a manufacturer of absorbent articles. Commonly said manufacturer acquires the pulp and then processes the pulp online in a manufacturing plant as the final article (eg, diaper, sanitary napkin) that is manufactured. Said processing steps may include defibrization of the pulp, addition of super absorbent and the like. In an online system, the speed with which the stages are carried out is limited by the different slower stages. An example of a pulp requiring such processing steps (e.g., defibrization) is described in U.S. Patent No. 5,262,005. The manufacturer's need to defibrize or otherwise process existing materials online means that the overall production process is substantially more complex. In addition, the manufacturer must acquire, maintain and operate the necessary equipment to execute said processing stages. The cost of general production is therefore increased. An absorbent material of the type produced by the process of the present invention can be incorporated directly into a desired absorbent article without the need for such processing steps. The manufacturer of the absorbent article does not have to defibe or otherwise treat the absorbent material made by the process of the present invention in any form other than the formation of the absorbent material within the desired shape. In this way, the manufacturer can streamline the assembly process and achieve substantial savings in cost and time.

The process of the present invention can be employed to make an absorbent material which also possesses a good ability to retain the absorbent material when subjected to mechanical stress.

FORMS OF ABSORBENT MATERIAL FOR USE IN H IG I ENE FEM PRODUCTS IN INA i FIGURE 4 illustrates a three layer form of an absorbent material 300 that can be made by the first embodiment of the process of the present invention and that is particularly suitable for use in feminine hygiene products. Said absorbent material has a basis weight from about 100 g / m2 to about 250 g / m2 and a density between about 0.25 g / cc and 0.5 g / cc. More preferably, the density is from about 0.28 g / cc to about 0.45 g / cc, and most preferably the density is between about 0.28 g / cc and about 0.33 g / cc. In one variation, the absorbent material 300 for use in the female hygiene product spread to the air as three layers or layers: a lower layer 301 containing pulp (without super absorbent) with a basis weight of approximately 25 g / m2; an intermediate layer 302 with a basis weight of about 150 g / m2 and containing from about 10 g / m2 to about 30 g / m2 super-absorbent 40C and from about 120 g / m2 to about 140 g / m2 of pulp; and a top layer 303 containing pulp (without super absorbent) with a basis weight of about 25 g / m2. In relation to the total basis weight of the absorbent material 300, the super absorbent level 40C ranges from about 5 to about 40 weight percent (g / m 2 of super absorbent per g / m 2 of material). Preferably, the super absorbent level is from about 7.5 weight percent to about 12.5 weight percent of the absorbent material 300. More preferably, the absorbent material 300 contains about 30 weight percent of super absorbent. absorbent. Thus, the intermediate layer 302 of the absorbent material preferably contains from about 1.5 g / m2 to about 25 g / m2 of super absorbent and from about 125 g / m2 to about 1 35 g / m2 of pulp and, more preferable from about 20 g / m 2 super absorbent and about 130 g / m 2 pulp. The intermediate layer 302 containing pulp and super absorbent may be laid out as a homogeneous combination or as a heterogeneous combination wherein the level of super absorbent varies with the proximity to the lower layer. If desired, the super absorbent could also be added to the lower layer. FIGURE 5 illustrates another form of an absorbent material 400 ÍÍ? .. SX. ? Sm-m- ÍI? .? • - íe ::? i-: t.r. ^ «G», & 3b t r i? 4 wherein the material is laid to the air by the process of the invention as four layers or layers, layer 401, layer 402, layer 403 and layer 404. Layers 402 and 403 may be characterized as two intermediate layers: a first layer intermediate 403 adjacent to upper layer 404, and a second intermediate layer 402 adjacent to lower layer 401. Each of the first and second intermediate layers independently comprises from about 10 to about 30 g / m2 of super absorbent 40D and from about 40 g / m2 to approximately 65 g / m2 of pulp. When it is desired to keep the absorbed fluid away from the top of the feminine hygiene product (i.e., away from the surface of the article that is in close proximity to the wearer) the amount of super-absorbent in the first and second intermediate layers 402 and 403 are adjusted so that there is a greater super absorbent in the second intermediate layer. The super-absorbent in the first and second intermediate layers 403 and 403 may be a same or different super absorbent. The lower layer 401 and the upper layer 404 does not contain any super-absorbent material. However, if desired, the super-absorbent can be added to the lower layer.

FORMS OF ABSORBENT MATERIAL FOR USE IN I NCONTI NDIA DIAGNOSTICS AND PRODUCTS feS- A á, Ls-A- &. * > & In another variation, the absorbent material made by the first embodiment of the process of the present invention is particularly suitable for use in diapers and incontinence products. Because such articles are expected to absorb and retain large amounts of less viscous fluid than a feminine hygiene article, said article employs absorbent material that is heavier and therefore has a preferred basis weight from about 300 g / m2 to about 50 g / m2. The general composite density of the material is between approximately 0.3 g / cc and 0.5 g / cc. More preferably, the overall composite density is from about 0.35 g / cc to about 0.45 g / cc, and more preferably about 0.38 g / cc. In a manner similar to that described above for a feminine hygiene product, a material suitable for use in diapers can be laid to the air as a layer or multiple layers such as two, three, four or more layers. When three layers are used (FIGURE 4), the lower layer 301 has a basis weight of approximately 50 g / m2; the intermediate layer 302 has a basis weight of about 300 g / m2 and contains from about 40 g / m2 to about 200 g / m2 of super absorbent 40C and from about 100 g / m2 to about 260 g / m2 of pulp; and the top layer 303 has a basis weight of about 50 g / m2. Preferably, the intermediate layer contains from about 70 g / m2 to about 170 g / m2 of super absorbent and from approximately 130 g / m2 to approximately 230 g / m2 of pulp. Even more preferably, the intermediate layer 302 contains approximately 80 g / m2 of super absorbent and approximately 220 g / m2 or approximately 160 g / m2 of super absorbent and approximately 140 g / m2 of pulp. The pulp and super absorbent intermediate layer can be laid as a homogeneous combination or as a heterogeneous combination where the level of superabsorbent varies with the proximity to the lower layer. If desired, the super-absorbent can be added to the lower layer. In a variation of four strata (FIG URA 5) used for pads and incontinence products for adults, the absorbent material 400 has two intermediate layers 403 and 403 each independently containing from about 20 g / m2 to about 100 g / m2 of Super-absorbent 40D and from approximately 50 g / m2 to approximately 130 g / m2 pulp. In a preferred embodiment the second intermediate layer (lower) 402 has a superior level of super absorbent 40D than the first intermediate layer (upper) 403. In this way, the absorbent material formed 400 has a tendency to keep the fluid absorbed away from the body surface of the user of the article. The super absorbent 40D in the first and second intermediate layers 403 and 402 may be an identical or different material. If desired, the super absorbent could be added to the lower layer. An absorbent material made through the process of present invention can be incorporated into an absorbent article as a single fold or multiple fold structure. The means for forming such structures that utilize folding are well known in the art. By way of example, a person skilled in the art can "fold in C", "fold in G" or "fold in Z" the absorbent material before incorporating it into the absorbent article.

MODIFIED FORM OF MATER IAL ABSOR BENTE FIGURE 6 illustrates another form of absorbent material 520 that can be made by another embodiment of the process of the present invention. The absorbent material 520 includes a tissue paper layer or carrier layer 522 as a first layer 524, a second layer 526, and a third top layer or layer 529. In the form of the absorbent material 520 illustrated in FIGURE 6, the layers 524, 526 and 529 define together a portion of the absorbent core 536 having a tissue paper carrier layer or tissue paper layer 522. In this particular embodiment, there is no transition layer or acquisition layer. However, there is an optional layer that can be provided, and said layer can have the structure and function that is identical with the structure and function of the transition layer described above with reference to the first embodiment illustrated in FIG. 2. same as with the layers of the first modality illustrated in .. ^ í- i ^ L.

FIGURE 2 and described above, layers 525, 526 and 529 of the embodiment shown in FIGURE 6 are referred to as layers or strata because the material forming such layers or layers is initially laid out in a form of the process of the present invention as separate layers or layers one on top of the other. One form of an apparatus or processing line for producing the absorbent material 520 illustrated in FIGURE URA 6 is described below with reference to FIGURE 7. After completion of the process of making the absorbent material 520, the layers or layers they are part of a unitary or integral structure. Commonly, there is little differentiating visual difference between the different layers. If one tries to separate the absorbent material in the layers or strata by which it was initially laid out in the manufacturing process, it will be found that the finished absorbent material does not easily separate or delaminate into the specifically identifiable layers or strata corresponding to the layers or strata spread in the production process. In the absorbent material 520, it is especially desirable that the tissue paper layer 522 be effectively and strongly bonded to the lower layer of the absorbent core portion 524 without adversely or adversely affecting the physical properties of the material 520, such as the integrity of pad, softness, bending ability, flexibility, adaptability and resistance to tension. * - $ í Jsia-, i i í ^ Á .... . The tissue paper layer 522 may have the same composition as the tissue paper layer 22 in the first embodiment of the absorbent material 20 described above with reference to FIG. 2. For the embodiment specific of the absorbent material 520 illustrated in FIGURE 6, the tissue paper layer 522 may be of a conventional type made from bleached pulp of 100% southern coniferous wood. The absorbent core portion layers 524, 526 and 529 each include pulp fibers 532 in a form as described above for the pulp fibers 32 of the first embodiment I of the absorbent material 20 illustrated in FIGURE 2. The material absorbent 520 preferably includes super absorbent particles or granules 540 in the first layer 524 and in the second layer 526 of the absorbent core portion 536. Said super absorbent particles 540 are dispersed through the two layers 524 and 526 substantially of the same way that the superabsorbent particles 40 are dispersed in the layers 24 and 26 of the first embodiment of the absorbent material 20 described above with reference to FIGURE 2. In the preferred embodiment of the absorbent material 520 illustrated in FIGURE 6, the third layer or top layer 529 does not include super absorbent particles 540. Although the super absorbent particles could be provided in the top layer 529, it is preferred in many applications that the top layer 529 be free of super absorbent particles. The concentration (percentage in weight) of the super-absorbent material 540 in each layer varies, such as the nature or type of the particular super-absorbent material.

PRODUCTION AND APPARATUS PROCESS: MODIFICATION The absorbent material 520 illustrated in FIGURE URA 6 can be made with the embodiment of the apparatus and process illustrated in FIGURE 3 and described above with reference to the manufacture of the absorbent material 20 illustrated in FIGURE 2 as well as a modified form of that apparatus and process. Said modified form of the apparatus and process for making the absorbent material 520 is illustrated in FIGURE 6 and is shown in FIGURE 7. The process accommodates the incorporation of a carrier layer in the absorbent material (e.g., tissue paper layer in the absorbent material 520 described above with reference to FIGURE 6.). For this purpose, a tissue paper web 62 is unwound from a tissue paper web 64 and directed onto the endless mesh 60 as shown in FIGURE 7. A series of forming heads 65 is provided on the endless maya. 60 to deposit the cellulose fibers. In the preferred form of the process, the series includes a first forming head 71, a second forming head 72 and a third forming head 73. A greater or lesser number of forming heads can be provided depending on how many layers of material are to be serviced.

• J &? ÁlLn LSjt.i? Í.- rkhrmAÁ lrr .. & & > . í, llr. rX ^ ^ r r i. SSüb rí - '.Ir. i -i - The cellulose fibers preferably include from a combination of (1) 100% processed southern pine kraft pulp, and (2) the cold caustic treated kraft processed pulp described above (e.g., pulp fiber) extracted cold caustic). The fibers are processed using a conventional hammer mill (not shown) to individualize the fibers. The individualized fibers are preferably combined with superabsorbent material, granules or particles in the separate combiner systems that supply the forming heads 71 and 72. The forming head 71 is connected to a combiner system 81, and the forming head 72 is connected to a combiner system 82. In some systems, the pulp fibers and super absorbent granules or particles are combined and transported pneumatically within the forming heads 71 and 72. The forming head 73 may have a combiner system 83, although the The combiner system 83 is not operated to combine the super-absorbent particles if the upper layer 529 of the absorbent material 520 does without superabsorbent. In other systems, the pulp fibers and super-absorbent granules or particles are transported separately to the forming heads and combined together in forming heads. The chemical bonding agents and the heat-set bonding agents are preferably not added during the fiber processing or during the combination of the fibers with the super-absorbent material. The combination and distribution of materials can -i i 4 controlled separately for each forming head. For example, in some systems, controlled air circulation and finned agitators in each combiner system produce a substantially uniform mixture and distribution (of the pulp fibers and the super absorbent particles for combiner systems 81 and 82 and of the pulp fibers alone for the combiner system 83). The super absorbent particles can be completely and homogeneously combined through the core portion Absorbent of the structure that is produced, or contained only in a specific layer or layers by the distribution of the absorbent particles for selected forming heads. If desired, the super absorbent particles can be discharged separately from separate forming heads 15 91 and 92 as individual layers 100% super-absorbent. In such optional configuration, the superabsorbent particle forming head 91 is located between the forming heads 71 and 72 and the superabsorbent particle forming head 92 is located between the forming heads 72 and 73. If the forming heads 20 separate superabsorbent particles 91 and 92 are used, then the super absorbent particles could also be combined in the combiner systems 81 and 82. Alternatively, only the pulp fibers could be transported exclusively to and through the combiner systems 81 and 82 and the forming heads 71 and 72 respectively, when the Super absorbent material is discharged from the forming heads 91 and 92. The material for each forming head is deposited with the aid of vacuum on the tissue paper web or carrier layer 62 to form a layered absorbent web. The layered absorbent web may, but not necessarily, be transported with the aid of a conventional vacuum transfer device 100 from the end of the endless may 60 to a moisture addition spray apparatus 150. The addition enclosure of steam 110 used in the first mode of the process illustrated in I FIGURE 3 is removed from the second embodiment of the process shown in FIGURE 7. The system could alternatively be designed to also remove the transfer device 100. The spray apparatus 150 includes six water spray nozzles across the width Of the plot. The number of nozzles can vary depending on the size or width of the processing line. Each nozzle is oriented to direct a water spray of conical pattern against the underside of the tissue paper layer web 62. Each nozzle is an automatic air atomization nozzle of Auto Variable Spray Jet model 1/8 VAA-SS + SUV67-SS sold by Spraying Systems Co., North Avenue on Schmele Road, PO Box 7900, Wheaton, Illinois 60189, U.S.A. Other types of nozzle could be used. The spray nozzles are located approximately 25.4 cm. below the tissue paper layer plot and they are separated i through the width of the frame in centers of 30cm. (ie, the distance between the adjacent nozzles is 30cm.J. The water pressure is adjusted to provide the desired amount of liquid sprayed against the web.In a currently preferred form of the process, the water pressure is maintained at about 1. 05Kg cm2 gauge to achieve a moisture addition of 3% by weight (based on the weight of the weft of absorbent material before the addition of moisture) .The water temperature is maintained at approximately 15 ° C. water could be higher or lower if desired.The type, arrangement, operation and number of the nozzles can be varied depending on the type of fabric, the composition and construction of the absorbent core portion 536, the size of the processing line, the speed of the line, the nature of the downstream processing and similar aspects In the currently preferred and contemplated embodiment of the process illustrated in FIGURE 7, the moisture content d of the weft is increased to effect a bonding of the tissue paper web weave 62 (finished product layer 522 in FIGURE 6) to the lower layer of the absorbent core portion without thermal bonding of the pulp fibers. After the moistened layer web passes under the moisture addition spray apparatus 150, it is compressed or compacted between a pair of heated calendering rollers, upper roller 121 and lower roller 122. This increases the density of the web. In the preferred form where the top layer is free of the super-absorbent material, the super-absorbent material in the underlying portion of the web does not contact or adhere to the heated top calender roll. The upper roller 121 is typically a steel roller and the lower roller 122 is typically a flexible roller having a hardness of approximately 85 SH D. Although both rolls could be uniform, in the preferred process, the upper roller 121 has a uniform surface and the surface of the lower roller 122 is not uniform. The lower roller could have a knurled surface. I Preferably, the lower roller 122 is characterized as a "linen roller" having a non-uniform surface having the three-dimensional configuration or printing of a linen-like fabric. The non-uniform surface functions to embed the tissue paper web 62 or other type of potting layer within the lower part of the absorbent material. Preferably, the indentations of the linen roll surface have a depth of more than 5% of the thickness of the carrier layer 522. A shape of a linen roll that has been used to make samples of the invention described below in the section entitled "EXAMPLES" is a linen roller designated with the Design Number 204RE87 and sold by Saveressig GmbH & amp;; CO. , Gutenbergstrasse 1 -3, D-48691 Vreden, Germany. The roller is made from a 42 CrMo metal alloy and is not nitrated. The diameter of the roller is 500mm, and the bullet width of the roller is 1. .1..: . . t-laugh 1, 950mm. The gravure width is 1, 850mm, and the gravure depth is 300 μm. Each roller 121 and 122 is preferably heated to a temperature between about 70 ° C and about 200 ° C, more preferably about 150 ° C. The weight of the upper roller 121 rests on the layered web. The additional force can be provided with conventional hydraulic actuators (not shown) acting on the axis of the roller 121. In the form of the process of the invention, the web is compacted between the rollers 121 and 122 under a load range I preferred from about 2,856Kg. strength / meter and approximately 40,769.4Kg. force / meter of the width of the transverse web, preferably of approximately 9, 192.75Kg. force / meter. It is now considered that the heated compaction increases the density of the web and the effects of hydrogen bonding of the pulp fibers together within the layers of the absorbent core portion 536 (FIG. 6), as well as from the tissue paper layer 522 to the pulp fibers in the lower layer 524 of the absorbent core portion 536. The compaction also increases the physical entanglement of the fibers. These factors increase the delamination resistance of the bond between the absorbent core portion 536 and the tissue paper layer 522. This also increases the strength and integrity of the finished absorbent material 520. This prevents the paper layer i i The tissue 522 is de-laminated from the lower layer 524 of the absorbent core portion 536 during the use of the material, such as during the manufacture of an absorbent product employing the absorbent material 520. This also provides a finished product with exceptional strength to the shaking of the super absorbent material. However, surprisingly there are no adverse effects on softness, adaptability and absorbency. A preferred range of the speed of the processing line is between about 30 and about 300 meters per minute, and the preferred speed is 90 meters per minute. The compressed and densified web is wound on a roll 130 using conventional winding equipment. A single layer or multiple layer absorbent material made from the embodiment of the process of the present invention illustrated in FIGURE 7 is of a relatively high density and has a composite density that is preferably greater than about 0 25 g / cc. In preferred embodiments, the absorbent material 520 has a composite density in the range from about 0.25 g / cc to about 0.50 g / cc. More preferably, the density is from about 0.28 g / cc to about 0.45 g / cc. An absorbent material can be prepared by the embodiment of the process of the present invention shown in FIGURE 7 on a wide range of base weights without affecting adversely affect its softness or resistance. Thus, the absorbent material can have a basis weight in the range from about 50 g / m2 to about 800 g / m2 and above. In a preferred form, the basis weight varies from about 100 g / m2 to about 500 g / m2. The embodiment of the process of the present invention shown in FIGURE 7 can be used to make an absorbent material having superior absorbent and packaging properties when compared to existing materials. The shape of the absorbent material that is made by the embodiment of the process illustrated in FIGURE 7 has a tissue paper layer that is attached to the absorbent core portion with relatively high strength. The only combination of a high-strength tissue paper joint and the overall material strength, absorbent capacity, good packing properties and adaptability of the absorbent material can be made by the process mode shown in FIGURE 7, have significant advantages for a converter or manufacturer of absorbent articles. The absorbent material can be handled and processed easily as the final article (e.g., diaper or sanitary napkin) that is made, and the absorbent material will withstand such non-traction handling of the tissue paper and without the material otherwise suffering a significant loss of tissue. the integrity. As a result, the manufacturer can process the absorbent material with better displacement capacity and decreased rupture. The samples of the absorbent material 520 illustrated in FIGURE 6 were tested to evaluate the integrity resistance of the material vis-a-vis the strength of the bond between the tissue paper layer 522 and the lower layer 524 of the absorbent core portion 536 Some of the samples were made by the process illustrated in a general manner in FIGURE 7. Other samples were also made by the process shown in FIGURE 7 except that no water was sprayed on the tissue paper layer and the calendering conditions were varied Even other examples were made by removing the tissue paper from a previously produced absorbent material by applying a layer of new tissue paper, and then in a laboratory water was added and the sample was heated on a flat press. As explained below in detail, the samples were tested for resistance to rupture or delamination when subjected to a tension force applied perpendicularly to the plane of the sample. As stated below in more detail, the test results were recorded and compared. The analysis of the results showed that the addition of water improves the bond between the tissue paper layer and the lower layer of the absorbent tissue paper portion. Also, the joint was improved in some way during the use of particular calendering conditions.

THE PROCESS OF THE PRESSURE PROCESS OF DEFLATION TO DETERMINE THE RESISTANCE TO THE DISCHARGE OF A PORTION OF ABSORBENT NUCLEUS WITH A LAYER OF TISU PAPER The delamination or resistance to the tensile stress of the samples was determined according to a test procedure set forth below. The test was used to calculate the degree of bond between the carrier tissue paper layer and the remainder of the absorbent core portion (pulp layers) of a sample of absorbent material. If, when a tensile force is applied to the sample perpendicular to the plane thereof, the sample is broken or pulled at the interface between the tissue paper and the absorbent core portion, then the bond strength corresponds directly to that Maximum applied force of tension. However, if the sample breaks within the core instead of the tissue / core interface, then the bond strength at the interface of the tissue core is at least as great as the core breaking strength. . A brand tension / compression testing machine Instron is used to apply a tension force to a 5.08cm circular sample. in diameter of a laminate of a tissue paper layer and an absorbent core portion, and the force was applied perpendicularly to the plane of the sample. Tension forces were applied on one side of the sample on the surface of the pulp and on the other side of the sample on the surface of carrier tissue paper that confronts in opposite manner until failure occurs. The force is transmitted from the test apparatus to the opposite confronting surfaces of the sample secured with double-sided tape to the dynapes of the machine as explained in detail below. This delamination test quantifies the tensile force necessary to break the sample within the absorbent core portion, or at the interface of the carrier tissue paper and the portion of the absorbent core if that interface bond strength is less than the resistance of the Absorbent core portion per se. The extent of the bond, or bond strength, between the tissue paper layer and the pulp of the absorbent core portion depends on many variables. A minimum level of bonding or adhesion is desired to maintain the integrity of the product. This is especially true for material that is subsequently processed in converting machines where the material is incorporated into absorbent article products such as cloth or feminine hygiene articles. The following items are used in the test: a) Brand compression / tension testing machine Instron model 554201 (reference number 600 in ta FIGURE 8) and a dedicated computer loaded with the Merlin brand software package as provided by Instron; ttA ¡rtr í b) 50 newton tension / compression load cell (reference number 610 in FIGURE 8); c) The Instron brand pivot union for the upper fixture plate; d) Hydraulic press model ATOM - SE - 15 Hudson Machinery Worldwide (reference number 620 in FIGURE 11); e) A circular dice of 5.08cm. in diameter (reference number 630 in FIGURE 1 1); f) 3M Scotch double-sided tape (# 41010DSLDO01AC502 D); g) Circular bronze upper plate (reference number 650 in FIGS RAS 8 and 9) having a platinum face with a diameter D1 of 5.024 cm.; and h) Lower stage (reference number 660 in FIGU RA 8) with a diameter greater than 5.08cm. First, the material from which the samples are to be taken is conditioned in a controlled environment at a temperature of 23 + 1 ° C and a relative humidity of 50% + 2% for a minimum of 2 hours. The density of the sample material is determined by calculating the volume of a sample as the arithmetic product of the measured thickness, length and width of the sample, and then dividing the measured weight by the volume of the sample. A strip of the sample material is prepared in a way that is Í.á L & .Í-g «> «Yft * ti at least 45.72cm. in length and more than 5.08cm. Wide. Alternatively, sufficiently smaller sections of the sample material 720 (F IGU RA 10) are obtained so that seven (7) circular samples, each of which has a diameter of 5.08 cm. can be created from this. Next, the sample material 720 is placed with the tissue paper layer 722 face down on a support surface 750 (FIG. RA 10). The release paper is removed only from one side of a Scoth 2-sided ribbon length 3M, 760 (FIG U RA 1 0). The exposed adhesive side of the tape 760 is applied to the side of the exposed pulp facing upwardly of the sample material 720 (F IG U RA 10). The upper surface release paper 7622 (FIGURE 1 0) is left in place on the tape 760 at that time. Then, as shown in FIG. 1, the sample material 720 with the attached tape 760 is placed in the bed 770 of the hydraulic press so that the carrier layer (tissue paper layer) is face down and the paper side of tape release is facing up. A circular sample 720 '(FIG U RA 12) is cut with a die using the 5.08cm circular die. of diameter 630 with the hydraulic press 620. The die cut sample 720 'has a tissue paper cut by die 722' on the bottom and has a piece cut by tape die 760 'and release paper 762' still attached to it. the top so that the sample 720 'can be shown to the test machine later, as . ^ 1 4 1 j is explained below, after the establishment of the test machine. For typical samples that have a tensile strength for rupture or delamination between 2 newtons and 1 1 newtons, a tension / compression load cell 610 of 50 newtons (FIGURE 8) is installed on the Instron cross-brand test machine for provide the appropriate sensitivity and at the same time have a sufficiently high range to withstand the initial compression load when the upper stage 650 is initially moved to first force the sample 720 'against the lower stage 660 between the tapes to cause the sample 720' Adhere to the platens as described in detail below. The circular metal bottom plate 660 (FIGURE 8) that has a diameter greater than 5.08cm. (for example, 20.32cm.) is used as the inferior accessory of the Instron brand machine. The computer is turned on and the Merlin brand software is launched. The vertical delamination test, which is listed as a compression method, is selected to activate the Instron brand machine. The following parameters of "Pre-Cycle" are established: Crosshead speed: 75mm / minute; and Maximum criterion: load of 35 newtons (a sufficient compression load to ensure that there is an assurance with resistant tape of the sample 720 'to the upper and lower platens as described in the detail below).

..Lí. ^ .. o- a -t. j.

A second strip of the Scotch 680 Scotch 680 double-sided tape (FIG. RA 14) is placed on the lower platen 660. Specifically, the release paper is removed from the underside of the tape strip 680 and the adhesive underside of the tape 680 is adhered to the lower stage 660 (FIGURE 14) in a location so that when the upper stage 650 is subsequently installed, the entire surface of the upper stage will be in vertical alignment with the second stage of ribbon 680 on the lower platen 660. Next, the release paper 690 removed from the upper side confronting upwardly of the second strip of tape 680 on the lower platen 660. The sample cut with previously prepared die 720 'is then bonded to top plate 650 (FIG U RA 1 3). is done by removing the side release paper 762 'of the tape 760' on the sample 720 'to expose the adhesive side of the tape 760', and then pressing the sample with the tape attached to the 5.08 cm surface. diameter of the upper circular bronze plate 650. The upper circular bronze plate 650 with the attached sample 720 'is then mounted with the retaining pin in the self-aligning clamping coupling (Instron catalog No. 2301 - 1 1 5) on the top attachment of the 600 mark machine. The Instron 600 brand machine is then set to locate the top circular bronze platen 650 so that it is at 6.35cm. from the lower circular plate 660.

* '• "* - *" - - * - »- The calibration length of the Instron brand machine is then established. The installation is verified to ensure that the movement of any random sample is minimal. The load of the Instron brand machine is balanced by pressing the "Balance" switch. The test starts by pressing the "Start" switch. During the test procedure, the upper stage 650 will initially move downward toward the lower stage 660 until the sample 720 is compressed with a force of 35 newtons (FIGURE 15) to create a junction of the upper stage 650, the double-sided tape 760 ', a sample 720', and to create a joint of the lower platen 660, in the double-sided tape 680 and the sample 720 '. After the compression force of 35 newtons is reached, the direction of movement of the upper stage 650 is automatically reversed, and the upper stage 650 will move upwardly away from the lower stage 660 at a speed of 75 mm / minute, and the sample will break or delaminate (FIGU RA 16). During movement of the plate 650 away from the plate 660, the sample 720 'will be subjected to voltage in the voltage mode. The maximum magnitude of the tension force during the tension mode will correspond to the extent of the junction between the broken or delaminated portions of the sample 720 '(FIGURE 16). I can indicate either that the bond strength between the ? ií, - tissue paper (carrier layer) and the core (if the tissue is delaminated from the core) or the core strength per se where the core per se breaks (if the strength of the bond between the carrier layer and the core is larger than the strength of the core per se After the sample 720 'has been broken or delaminated, the upper stage 650 is removed from the 600 mark machine, and the sample pieces are removed from the Upper and lower plates A new sample can be prepared and mounted to the upper plate as described above, and the upper plate can be reinstalled on the Instron machine and returned to the calibration length by pressing the "Return" switch. 7 samples The breaking force or delamination (which is the maximum positive value in the force curve generated by the graphing software) for each of the seven samples is recorded and the average value is calculated. The typical force is shown in FIGURE 17.

OTHER PR OBAAS AND MEASUREMENT ES Other physical characteristics of the material from which the rupture or delamination resistance test samples were taken are determined by additional testing.

BASE WEIGHT DETERMINATION The basis weight of the absorbent material from which samples are taken for the delamination resistance test is determined from the sample of the material by first weighing the sample. The length and width of the sample are measured. The length and width are multiplied to calculate the area. The weight is then divided by the area and the coefficient is the base weight.

DETERMINATION OF DENSITY The density of the absorbent material from which the delamination resistance test samples are taken is determined from a sample of the material by first weighing the sample. The length, width and thickness are measured and multiplied to calculate the volume. The weight of the sample is then divided by the volume to calculate the density.

DETERMINATION OF R IG IDEZ GURELY The "Gurley rigidity" of the absorbent material from which the delamination resistance test samples are taken is determined from a sample of the material being tested in accordance with the conventional Gurley Rigidity test used in the fiber technique. non-woven absorbent. The Gurley Rigidity values of the absorbent material are measured using a . . r ««.,? * ^ .. ^? M, *** ... ... L- ~ 2l. «t .tot tr? Aá Rigidity (Model No. 4171 E), manufactured by Gurley Precision Instruments of Troy, New York,, U.SA The instrument measures the externally applied moment required to produce a determined deflection of a test sample strip of the specific dimensions fixed at one end and having a concentrated load applied to the other end. The results are obtained in "Gurley Rigidity" values in units of milligrams. The greater the rigidity of the material, the less flexibility and therefore the lesser softness of the same.

I RESISTANCE TO TENSION The tensile strength of the absorbent material from which the delamination resistance test samples are taken is determined from a sample of the material that is tested according to the conventional tensile stiffness test used in the test. technique of non-woven absorbent fiber. The values for tensile strength of a specific material width and length are determined by applying a force longitudinally to the plane of the sample at a specified constant rate of extension in accordance with the test designated Strength of Tension No. 20.2-89 of European Disposable And Nonwoven Association ("edana") and ISO 9073-3: 1989 (EN 29073 part 3). Five (5) samples of elongated material were cut with -, • 4. A * A «* m length parallel to the machine direction of the material. Each test piece is 50 + 0.5 wide and has a sufficient length to allow jaw separation of 200mm. The test samples are conditioned according to ERT 60.1-75. A constant extension speed of 200mm / minute is applied by the tension test machine (dynamometer) that holds the test sample between the jaws of the tension machine initially located at 200 + 1 mm. from separation. The force-elongation curve is recorded. The tensile strength is determined by reading the highest value of the force / elongation curve. EXAMPLES Example 1 Strength tests according to the above-described test were conducted on samples of absorbent material having the structure of absorbent material 520 illustrated in FIGURE 6. In Example 1, samples were taken from material 520 as produced through the embodiment of the process illustrated in FIGURE 7, except that the addition of water spray by means of the nozzle apparatus 150 was not operated. Therefore, water was not added to the material during processing. The material 520 was produced with (1) an upper layer 529 having a basis weight of 42 gsm (grams per square meter) and 0% super absorbent polymer ("SAP"), (2) an intermediate layer 526 that i has a basis weight of 89 gsm and 47.7% super absorbent polymer by weight compared to the weight of the pulp numbers in the layer, and (3) a lower layer 524 having a basis weight of 102 gsm and 45.7% of super-absorbent polymer in weight compared to the weight of the pulp fibers in the lower layer. In each sample, upper layer 529 and intermediate layer 526 contained pulp that had 100% processed southern pine Kraft pulp. The lower layer 524 southern pine pulp in a combination of 84% by weight of Kraft processed pulp and 16% by weight of processed cold processed kraft pulp where the cold caustic treatment is as defined above with reference to the application U.S. Patent No. 08 / 370,571 filed January 18, 1995 and as described above with reference to the pulp fibers used in layers 24, 26 and 28 of the absorbent material 20 shown in US Pat. FIGURE 2. The super-absorbent material 540 in the sample material of Example 1 was in the form of particles sold under the designation No. 7440 by Stockhausen GmbH, Krefeld, Germany and having their offices at 2401 Doyle Street, Greensboro, North Carolina 27406, USA The tissue paper layer of the material 520 was provided as a weft in a roll for use as the weft layer 62 in the process shown in FIG. 7. The tissue paper is sold by Cellu Tissue Corporation, 2 Forbes Street, East Hartford, Connecticut ± t ??, i & . - »jm.» < m. . -. ^ "" "- -, -t .1 .i 06108, United States of America Four grades of tissue paper were used to provide various forms of absorbent material 520: Tissue Paper Grade 3007, Tissue Paper Grade 3007X, Tissue Paper Grade 3007Y, and Tissue Paper Grade 3008. Each grade of tissue paper was produced from 100% southern conifer wood and the grades have the characteristics set forth in Table 1A, where "MD" refers to the machine direction of the tissue paper manufacturing line and "CD" refers to the transverse direction of the tissue paper manufacturing line.

TABLE 1A The embodiment of the process illustrated in FIGURE 7 was used to produce four (4) operations of the absorbent material 520 illustrated in FIGURE 6, each operation having one different from the four grades of tissue paper listed in Table 1 A. The apparatus Water nozzle 150 was not operated so that no water was added. The process was operated at a linear speed of 90 meters per minute. The upper roller 121 and the lower roller 122 were each maintained at a temperature of 150 ° C. The web was compacted between rollers 121 and 122 under a load of 5,622.75Kg. of force / meter. The upper roller 121 has a uniform surface, and the lower roller 122 was a "linen" roller with a non-uniform surface. From each of the four operations, seven (7) samples were prepared and tested according to the delamination test procedure described above. For each operation, the test values of the delamination force (i.e., the sample breaking force) were averaged in order to provide an individual average delamination force. The average delamination force is listed as the "Average Delay Resistance" in the following table 1B for each of the four operations (designated as Sample Operation 1, Sample Operation 2, Sample Operation 3 and Operation of Sample 4). Et Table 1 B also lists the basis weight, the density, the Gurley I Stiffness, and the tensile strength in the direction of the m? á.? lm .ÍÍ l, r .. .. i - i. m.m *. . machine of a sample of the material in each operation. Table 1B also includes a delamination test force for the average of seven (7) samples from a fifth operation, a control operation labeled "Control Operation 1", and a delamination test force for the average of the seven (7) samples of a sixth operation, a control operation labeled "Control Operation 2". The material of Control of Operation 1 and Control of Operation 2 were made by the process described above for the four operations from which the data for Sample Operations 1, 2, 3 and 4 were generated except that of the Operation of Control 1 and Control Operation 2 that did not use a lower linen roller 122. Instead, the lower roller 122 for Control Operation 1 and Control Operation 2 was a roller with a uniform surface similar to the upper roller 121 The Control Operation 1 material included grade 3007 tissue paper and the Control Operation 2 material included grade 3008 tissue paper. The composition of the absorbent core portion was identical in Control Operation 1 and the Operation of Control Paper 1. Control 2 and was the same as the absorbent core portions of sample operations 1, 2, 3 and 4. - &- • « The values in Table 1 B show the strength values for the delamination resistance at which the tissue paper drawn from the absorbent core (i.e., the separation of the tissue paper layer 522 from the bottom layer of the absorbent core portion). 524). 5 These values are for material samples to which water was not added during the manufacturing process (ie, the water addition apparatus 150 in FIGURE 7 was not operated). The test results show that the different grades of tissue paper extracted from the absorbent core portion in the forces of 10 delamination of less than 6 newtons. It should also be noted that the resistance to delamination can be increased by the use of a non-uniform roller or linen roller compared to a uniform roller. For example, in Control Operation 2 (which uses uniform rolls), the resistance 15 to delamination was only 2.17 newtons for a tissue plot of Grade 3008, although it was much higher (ie, 5.12 newtons) for the weft with a tissue paper of Grade 3008 in Sample Operation 4 (using the roller of inferior linen with a surface not nif m immediately below.

Example 2 The effect of the addition of moisture (eg, water) to the tissue paper during the process of making the absorbent material was investigated. In Example 2, the process mode illustrated in FIGURE 7 was operated as in Example 1 described above, albeit with water sprayed against the tissue paper web for operations using three different tissue papers and without water sprayed against the tissue. tissue paper for the other two "control operations". Table 2 lists the characteristics of the material produced in each operation in Example 2. The upper layer 529, the intermediate layer 526 and the lower layer 524 of the absorbent core portion 536 for the operations of Example 2 had the same pulp composition. and super-absorber than in Example f. The processing line (FIGURE 7) was operated at the same speed and at the same calendering roll temperature and compression force as in Example 1. For Sample Operations 1, 3, and 4 in Table 2, the water was sprayed from the above-described nozzles of the device 150 (FIGURE 7) against the bottom of the tissue paper layer web 62 at a distance of 25.4 cm. under the frame 62. Six nozzles were separated in centers at 30cm. through the width of the frame. The water was supplied to the nozzles at a pressure of ^^^^^^^^^^^^ m -fi -il t - * '* ^ 1.05KgJcm2 manometric and at a temperature of 15 ° C at a speed to produce an addition of 3% moisture based on the weight of the weft of absorbent material before the addition of moisture. Immediately after the weft passed through the calendering rolls, the moisture content of the weft was low. However, after the samples had reached equilibrium with the ambient atmosphere, the moisture measurement in the material in each Sample Operation 1, 3 and 4 showed that the moisture content was in the range from 4% to 4.5. % by weight based on the total weight of the sample with the humidity included. For the Control Operation and the Control Operation listed in Table 2, both calendering rolls 121 and 122 were uniform. For Sample Operations 1, 3 and 4 in Table 2, lower roller 122 was a knurled linen roller, and upper roller 121 was uniform. The identification of the tissue paper grades used in the operations of Example 2 listed in Table 2 correspond to the tissue paper grades of Example 1 listed in Table 1A above. For Control Operation 2 samples were tested to determine the average delamination resistance in the Table 2, the tissue paper was first manually removed in the laboratory before testing, so that only the core portion , , Item ? ^ ^ _ _ ^ ..... ".,. ". ^ ^. ^. m .. m m? ... L i Table 1 B and Table 2 can be compared to show the effects of moisture addition. The bond strength between the tissue paper and the absorbent core portion improves when moisture is added. Table 1 shows that in the sample operations 1, 2, 3 and 4 where no water was added, the tissue paper was removed from the core before the core could delaminate. On the other hand, Table 2 shows that in the sample operations 1, 3 and 4 where water was added, the tissue paper was bound so tightly that it was not extracted, and the core was delayed instead. Table 2 also shows that there is a significant improvement in the integrity of the absorbent core portion per se (portion 536 in FIGURE 6) when water was added during the process illustrated in FIGURE 7. Control Operation 2 in the Table 2 was produced without the addition of water and the tissue paper was manually removed in the laboratory before the delamination test was conducted on the Control Operation 2 samples. The nuclei of the sample of Control Operation 2 were broke or delaminated with a resistance to average delamination of 3.42 newtons. This is considerably less than the resistance to average delamination of the samples tested for Sample Operation 1, Sample Operation 3 and Sample Operation 4, where the frame was processed with the addition of water and where the core was broke or delayed in average resistance values exceeding 7 newtons (considerably higher than the core delamination resistance value of 3.42 Newtons for the sample average of Control Operation 2).

Example 3 Example 3 investigated the effect of water sprayed on tissue paper on a laboratory scale. The absorbent material having the structure illustrated in FIG. URA 6 was used, although the composition of the absorbent material differed from that described in Example 1 and Example 2. Specifically, the material 520 (FIG. 6) was used in the Example 3 and was produced with a top layer 529 having a basis weight of 25 gsm and 0% super absorbent polymer, an intermediate layer 526 having a basis weight of 225 gsm and 57% super absorbent polymer by weight in comparison with the weight of the pulp fibers in the layer, and a lower layer 524 having a basis weight of 233 gsm and 54% super absorbent polymer by weight compared to the weight of the pulp fibers of the lower layer. In each sample, the upper layer 529 and the intermediate layer 526 contained pulp that was pulp processed from 100% south pine kraft. Bottom layer 524 included southern pine pulp in a combination of 78% by weight of a Kraft processed pulp 22% by weight of a cold processed caustic Kraft processed pulp where the cold caustic treatment is as defined above with reference to the patent application of the , Í. ¿I .i. i. : ...,. i. i. at ^ i United States of America Serial No. 08 / 370,571 filed on January 18, 1995 and as described above with reference to the pulp fibers used in layers 24, 26 and 28 of the absorbent material 20 shown in FIG. 2. The super absorbent material 540 in the sample material of Example 3 was in the form of particles sold by Stockhausen under the designation described above No. 7440. The tissue paper layer 522 (FIGURE 6) was Grade 3008 ( 1A above). The absorbent material for Example 3 was prepared in a processing line as illustrated diagrammatically in I FIG. 7, but without the operation of the water addition device 150 to prevent the addition of water to the formed web. The processing line was operating at a speed of 35m. per minute. The upper roller 121 and the lower roller 122 were each maintained at a temperature of 140 ° C. Both the upper roller 121 and the lower roller 122 were of uniform surface and the weft was compacted between the rollers under a load of 5., 622.75Kg. force / meter. After the absorbent material was formed, a sample of the formed material was taken and the tissue paper layer was manually removed from the sample. A new piece of tissue paper was placed on the absorbent core (Grade 3008 tissue paper in Table 1A). In a first sample, Sample 1 of Example 3, the new tissue paper without the addition of water, was attached to the core in a press heated to 148.8 ° C and at a pressure of 8.43 kg / cm2 for 60 seconds.

JAil ¿.é, Amk.ilm. mm.tUÍ-í.m, m, l .A seconds. No water was added. A second sample, Sample 2, was prepared in a manner identical to Sample 1, except that before Sample 2 was placed in the heated press, the new tissue paper on Sample 2 was sprayed with water to increase the humidity up to 4% by weight of the weight dried in the sample oven. Moistened Sample 2 was then pressed into the heated press under the same conditions as Sample 1. A third sample, Sample 3, was prepared in the same manner as Sample 2 described above, except that the amount of water added was 1 1% by weight of the dry weight in the sample oven. Finally, a Control Sample was prepared, and it consisted only of an absorbent core material produced in the processing line of FIGURE 7 in the same way as the material used to make the samples 1 and 2, except that the material for the control sample was produced without adding water and after removing the tissue paper before the delamination test. Table 3 presents the results of the resistance tests to the delamination of the samples. The upper standard deviation for Sample 2 is due to the lack of uniformity in the sprinkling of water in the laboratory spray system.

This results in variation in the bond between the tissue paper and the core. The data in Table 3 show that the addition of the l * - t- &? > ? > * - r > . The moisture improves the binding of the absorbent core portion to the tissue paper.

In the case of Sample 1, there is very little union between the core and the tissue paper. In the case of Sample 3, the tissue paper was also bound within the core that the core disintegrated first, and the greater strength or strength of the bond between the tissue paper and the core could not be measured. However, there is a general tendency towards substantial improvements in the bond through the addition of water.

Example 4 The type of laboratory investigation described in Example 3 was conducted in Example 4 on absorbent material having the same structure illustrated in FIGURE 6 and the same layer composition (i.e., percentage of super absorbent, percentage of kraft pulp and percent caustic treated cold) as used in the material in Examples 1 and 2. The absorbent material from which the test samples of Example 4 were taken was initially produced in the same manner as in the aforementioned Example 3. However, a control sample of an absorbent core was prepared from the absorbent material produced on the processing line illustrated in FIGURE 7 without the addition of water and I then the tissue paper was removed from the core. This control sample is identified in Table 4 below as the "Control Sample". Sample 1 was prepared from an absorbent core with the anterior tissue paper (Grade 3008) removed manually. A new tissue paper (Grade 3008) was placed on the core, and the ensamable was pressed in a heated press 148.8ßC and at 8.43KgJcm2 for 60 seconds. No water was added. A second example, Sample 2 was prepared from an absorbent core with the removed tissue paper removed (Grade 3008). The new tissue paper (Grade 3008) was placed in the absorbent core and water was sprayed onto the tissue paper side of the core to increase the moisture content to 11% by weight compared to the dry core weight. The assembly was then hot-pressed in the same manner as in Sample 1 of the Example 4 described above. The samples were then tested for resistance to delamination and the results are set forth in Table 4 below.

TABLE 4 Table 4 shows that the resistance to delamination of the material without the addition of water was less than the resistance to delamination of the material when water was added. In the case of Sample 1, there is very little union between the core and the tissue paper. Also, due to the limitations of the laboratory spray system, it was not possible to add a lower dose of water than 11%. Therefore, the 11% load was used. The upper standard deviation for Sample 2 is due to the lack of uniformity in water spraying. This results in some variation in the bond between the tissue paper and the core. These dates tai ík * áaMM¿st? t i show that the addition of moisture improves the binding of the absorbent core portion to the tissue paper.

EFFECT OF THE ADDITION OF HUMIDITY ON ABSORBENT MATERIAL As described earlier in the section entitled "PRODUCTION AND APPARATUS PROCESS: FIRST MODALITY", moisture (eg steam or water spray) can be added to the absorbent material to effect the establishment of hydrogen bonding of pulp fibers each other, within the core portion (pulp layers), as well as from the tissue paper layer to the pulp fibers of the core portion, to increase the strength and integrity of the finished absorbent material. It has been found that, contrary to conventional expectations, the addition of moisture does not significantly increase the rigidity of the finished material. The production of a finished absorbent material with increased integrity and strength from hydrogen bonding, but without increased stiffness, is highly desirable when the material is to be used in absorbent products such as disposable diapers and feminine hygiene products that must be soft and flexible Samples of absorbent material were tested for strength and rigidity. For some of the samples that were tested they did not have added moisture, and some of the samples l .l .. m 'Sá. mm ...,.? -. ....- ..L Í..MJ :. .? .Í., Were tested after the addition of moisture. The test results are presented in Table 5 below. Table 5 lists the values for the Gurley Stiffness and the Stress Resistance in the Machine Direction that were determined by several test samples of the material of Sample A, the material of Sample B and the Control material. For each sample A, sample B and control materials, six test samples were tested for the Gurley Stiffness values and the average value was calculated and listed in Table 5. For each of the sample materials A, Sample B and control, 5 samples were tested for the tensile strength in the Machine Direction and the average value was calculated and listed in Table 5. The Gurley Stiffness test was conducted as previously established in the section titled "DETERMINATION OF GURLEY RIGIDITY", and the Stress Resistance test in the Machine Direction was conducted as stated earlier in the section entitled "TENSION STRENGTH". The material of Sample A, material of Sample B and the Control material listed in Table 5 were initially taken from the absorbent material produced according to the process described in Example 3 set forth above. Therefore, no water spray was used in the initial production of the material used for the tests in Table 5. However, unlike in Example 3, the tissue paper layer was not manually removed from the finished production material used for the tests of Table 5. Control samples from Table 5 were taken from the production material without further processing and were tested to determine the Gurley Rigidity values and the Stress Resistance values in the Machine Direction listed in Table 5. For the samples of Sample A of Table 5, before conducting the stiffness and resistance tests, the water is sprayed against each layer of the upper pulp of the sample (ie, the upper layer 529 in FIGURE 6) to increase the moisture content to 5% by weight of the initial dry sample weight. Samples of Sample A were then pressed in a flat press heated to 148.8 ° C and at a pressure of 8.43KgJcm2 for 30 seconds. For the samples of Sample B of Table 5, before conducting the stiffness and strength tests, a new additional layer of tissue paper was applied to the upper pulp layer (i.e., the upper layer 529 in FIGURE 6) , and then the exposed surface of the new tissue paper layer on each sample was sprayed with water to increase the moisture content to 5% by weight of the weight of the initial dry sample. The additional tissue paper applied to the top layer was of the same type of tissue paper as in the bottom layer (ie, Grade 3308 tissue paper identified in Table 1A as described above with reference to Example 3). The samples of Sample B were then pressed in a flat press heated to 148.8 ° C and at a pressure of 8.43Kg / cm2 for 30 seconds. For each of the materials of Sample A, Sample B and Control, six samples were also measured to determine the base weight and density, and the average values of the basis weight and density, and the average values of the basis weight and density were calculated and noted in Table 5. For the materials of Sample A and Sample B, the basis weight and density were determined after the samples were removed from the heated press. The base weights listed in Table 5 were determined as described above in the section entitled "BASE WEIGHT DETERMINATION". The densities listed in Table 5 were determined as described above in the section entitled "DETERMINATION OF DENSITY". Table 5 shows that the average value of the tensile strength of the control material (to which no water was added) was 15.57 Newtons. Compared to the average tensile strength values of Sample A and Sample B of 25.42 newtons and 27.25 newtons, respectively, the resistance of 15.57 newtons of the Control material is considerably lower. The tensile strength of the material of Sample A and B when the moisture was added is at least about 63% greater than the tensile strength of the control material to which no moisture was added. Furthermore, and unexpectedly, the Gurley Stiffness of Sample A and B material did not increase to an important degree in - - > .. -Í.-Í. i. i. »•; Comparison with the Control material. This increase was less than 0.01% for Sample B and the increase was less than 3.5% for Sample A (which includes the second top layer of tissue paper). Therefore, the addition of moisture facilitated the creation of oxygen bonds which increased the strength of the material without undesirably increasing rigidity. Even in samples of the material of Sample B, to which a second layer of additional tissue paper was added, the stiffness did not increase significantly compared to the control material. TABLE 5 It will be readily appreciated from the above detailed description of the invention and the illustrations thereof that numerous variations and modifications may be made without departing from the true spirit and scope of the novel concepts or principles of the invention.

Claims

CLAIMS 1 . A process for making an absorbent material comprising the steps of: (A) forming a web having at least one layer including cellulose fibers free of added chemical binders and heat set bonding agents; (B) Increasing the moisture content of said web by adding between about 1% and 8% moisture, based on the total weight of the web before the addition of moisture, to increase the density of the web; and (C) After step B, compact the screen at an elevated temperature to increase the density of the screen. The process according to claim 1, further including before step (A), the steps of: (1) treating a liquid slurry of pulp containing the cellulose fibers at a temperature from about 15 ° C to about 60 ° C with an aqueous alkali metal salt solution having an alkali metal salt concentration of from about 2 weight percent to about 25 weight percent of said solution for a period ranging from about 5 minutes to about 60 minutes, and (2) combine the cellulose fibers and the super-material ÍA rm H Jmíü? - ,. .. »S" * a ^. M & ill ... ¿m. k. TO. Absorbent with controlled air circulation and mechanical agitation to form a mixture of cellulose fibers and super absorbent material. 3. The process according to claim 1, wherein step (B) includes injecting steam at low pressure into an enclosure adjacent to a side of the weft or spraying water against a side of said weft. 4. The process according to claim 1 in the step of the step is included to compact the web between two calendering rollers where both rollers are maintained at temperatures in the range between about 70 ° C and about 200 ° C and where one of the rollers has a uniform surface and the other of the rollers has a surface that has indentations; and compacting the web between the rollers under a load of between about 2,856 and 40,769.4 kilograms force / meter of the width of the transverse web. 5. The process according to claim 1, wherein step (A) includes forming the weft to include the carrier layer on which at least one layer of a mixture of cellulose fibers is placed. 6. An absorbent material that (I) is made by the process comprising the steps of: (A) forming a weft having a layer of tissue paper on which is placed at least one absorbent layer that jáuÍÁZLS, .., rltláttA. * - - -ípt .. ».- contains cellulose fibers free of added chemical binders and thermofixed bonding agents; (B) increasing the moisture content of the web between about 1% and about 8% by weight based on the weight of the web before the addition of moisture; and (C) after the step of sub-enclosure (B), compacting the weft at an elevated temperature to further increase the density of the weft and to effect an increased binding of the tissue paper to said at least one absorbent layer; and (II) has a bond strength between the tissue paper layer and said at least one absorbent layer that exceeds a delamination force of 3 newtons. The absorbent material according to claim 6, wherein step (C) includes compacting the weft between the calendering rolls which are maintained at temperatures in the range of between about 70 ° C and about 200 ° C, wherein one of the rollers has a uniform surface and the other of the rollers has a non-uniform surface that defines indentations having a depth of more than 5% of the thickness of said tissue paper layer to contact the tissue paper so that the embedded portions of the tissue paper in said at least one absorbent layer and in the weft are compacted between the rolls under a load of between about 2,856 and about 40,769.4 kilograms force / meter of the width of the transverse weft. 8. An absorbent material that is made by the process comprising the steps of: (A) forming a web having a layer of tissue paper on which is placed at least one absorbent layer containing cellulose fibers free of chemical binders aggregates and heat-set bonding agents; (B) applying water to the web to increase the moisture content of the web between about 1% and about 8% by weight based on the weft inmate prior to the addition of moisture; and (C) after step B, compacting the weft at an elevated temperature to further increase the density of the weft and to increase the tensile strength of the weft of the material by at least 60% without increasing the R ig Gurley more than 0.01% compared to the elaboration of the material omitting stage (B). 9. An absorbent material comprising: a weft having a carrier layer on which is placed at least one absorbent layer containing at least cellulose fibers free of added chemical binders and heat set bonding agents; the web having a density between about 0.25 grams per cubic centimeter and about 0.5 grams per cubic centimeter; the plot that has a basis weight between approximately 150 l »t.». Í.2Í .Í? grams per square meter and approximately 600 grams per square meter; the plot that has a Guild Rigidity of less than approximately 1,500 milligrams; the weft having a tensile strength in the machine direction greater than about 9 newtons; and the web having a bond strength between said at least one absorbent layer and the carrier layer exceeding a delamination force of 3 newtons. 10. The absorbent material according to claim 9, wherein some of the cellulose fibers are made by first treating a liquid suspension of the pulp containing said cellulose fibers at a temperature of about 1.5 °. C to about 60 ° C with an aqueous alkali metal salt solution having an alkali metal salt concentration of from about 2 weight percent to about 25 weight percent of said solution during a period ranging from about minutes up to about 60 minutes; said at least one absorbent layer including from about 10 percent by weight to about 60 percent by weight super absorbent material based on the total weight of said at least one absorbent layer with the super absorbent material; and the web including an absorbent layer of said fibers of ifi-iil? Án? RlMt Utj t? -1,.?. ,. m ^ mm. ? Cellulose which are free of superabsorbent material and which have at least one absorbent layer on the top of the diaphragm. , .. itá it.?.1. í: < mine. i