MXPA97006807A

MXPA97006807A - Fibrous band that has improved resistance and method of manufacturing of the mi

Info

Publication number: MXPA97006807A
Application number: MXPA/A/1997/006807A
Authority: MX
Inventors: D Halabisky Donald; West Hugh; M Grant Terry; S Hajnal Andre
Original assignee: Weyerhaeuser Company
Priority date: 1995-03-06
Filing date: 1997-09-05
Publication date: 1998-07-03

Abstract

The present invention relates to a fiber band which is bonded to one another by means of a binder which has been activated by partially solubilizing the binder medium with a solvent therefor: the fibers are insoluble in the binder medium, partially solubilized, sticky and flow in contact with the fibers and with it, then, the solvent is absorbed by the binding medium, leaving the binder medium to solidify again and join the fibers in a matrix, increasing the resistance of the

Description

FIBROUS BAND THAT HAS IMPROVED RESISTANCE AND METHOD OF MANUFACTURE OF THE SAME RELATED REQUESTS This application is a continuation in part of copending patent application above Serial No. 08 / 399.408, filed March 6, 1995, the benefit of the filing date under 35 U.S.C. claimed § 120.

FIELD OF THE INVENTION The present invention relates to fibrous webs and methods for manufacturing same, more particularly, to webs containing pulp cellulosic fibers, and most particularly to webs of pulp cellulosic fibers having an internally bonded matrix that increases wet strength and / or dry of a structure made of the band.

BACKGROUND OF THE INVENTION Wood pulp fibers are used in a variety of absorbent products. The wood pulp fibers are formed into bands which are then placed in different structures, for example, diapers, incontinence products, and feminine hygiene products. Because the bands of pulp fibers do not inherently have high wet or dry strength, especially in tension, different methods have been devised to improve the wet and dry strength of the bands, so that the final product in which they are incorporated have superior resistance characteristics. Frequently, the bands produced from wood pulp fibers are produced using the conventional air-laying process to provide a low density foamed product. The resistance of these bands to the air has been increased by a variety of techniques. One of these techniques is to spray a latex on one side of the band after it is formed. That band dries up and then turns around. The latex is then sprayed on the back of the band and also dried. Normally, the latex used are about 50% solids (the balance being water) and sprayed onto the strips at a rate of ten (10) to thirty (30) percent based on the weight of the fiber. This requires that a significant amount of water be removed from the band during the treatment. Also, to develop wet strength, formaldehyde is often embedded in the latex formulation to entangle and insolubilize the resin after it is dried. Although this process produces a band of reinforced wood pulp, it has several disadvantages. These include the substantial energy required to dry the latex; a significant capital cost for the storage, spraying and drying of latex; environmental and management problems associated with latex and formaldehyde; and high latex costs due to the amount needed to provide an adequate increase in strength. Moreover, excess spray latex originating inherently spray finally covers the area surrounding the spray apparatus, requiring significant effort and expense of work. Finally, a latex can only be used on thin products because the latex does not penetrate well below the surface of the strip. Thermal bonding has also been used to reinforce the bands laid to the air. In this process, thermally sensitive fibers or powders are added to the fiber system before the mixture is laid in a band. These fibers are fused by passing them through a hot oven or calender. Again, this procedure produces a significant increase in wet and dry strength. However, the procedure has significant disadvantages, including the high capital cost of thermal bonding furnaces with accurate temperature control systems; the time required to bond thermally, which usually creates a bottleneck in production, and the formation of fiber and dust in furnaces that can cause fire hazards. In addition, the existing production lines of pariales do not have the physical space required for bulky agglutination furnaces. Also, thermal bonding materials are generally not biodegradable, a highly desirable attribute for disposable products. Thermal agglutination also decreases absorbency because the thermal bonding materials are generally hydrophobic.

BRIEF DESCRIPTION OF THE INVENTION In accordance with a broad aspect of the present invention, an article is provided comprising a band of pulp cellulosic fibers that are freely intermingled with one another. An agglutination medium is placed in contact with at least part of the pulp cellulosic fibers for the purpose of mutually bonding at least part of the pulp cellulosic fibers to form a reinforced web. The agglutination occurs through the action of solubilization of a solvent for the agglutination medium. The pulp cellulosic fibers are insoluble in the solvent. The solvent has a limited volatility of up to 29 kPa at 25 ° C. The agglutination medium is contacted with the fibers, for example, by dispersing the agglutination medium through the entire pulp cellulosic fiber web, or by placing a layer of agglutination medium on the cellulose pulp fiber web, or placing the agglutination medium in contact with only some of the pulp cellulosic fibers. When the agglutination medium contacts the solvent, the surface of the agglutination medium is at least partially soluble, making it sticky when the agglutination means adheres to at least part of the pulp cellulosic fibers. However, the solvent is present in an insufficient amount to completely solubilize the agglutination medium. In contrast, after partially solubilizing the surface of the agglutination medium, the solvent is dissipated, for example, by being sufficiently absorbed by the agglutination medium, to allow the surface of the agglutination medium to solidify again, resulting in the binding permanent of the agglutination medium, either with itself, or with at least part of the cellulosic fibers. The whole procedure can be facilitated with heat. This agglutination mechanism significantly increases the wet and dry strength of a resulting web without the concurrent disadvantages of prior art reinforcing methods. In a preferred embodiment, the agglutination means comprises second fibers which are either the agglutination medium alone or are fibers coated with the agglutination means. These second fibers are intermixed by all the pulp fibers in the web, or are located in layers on one or both sides of the pulp fibers in the web. When the solvent makes contact with the second fibers, the surfaces of the second fibers partially solubilize and become sticky. The sticky surfaces of the second fibers contact and adhere to one another and to the pulp fibers. As the solvent dissipates, as it is absorbed by the second fibers, the surfaces of the second fibers solidify, forming permanent bonds between the pulp fibers and the second fibers. The resulting bonded web exhibits superior strength characteristics that are useful, for example, in absorbent structures such as diapers, feminine hygiene products and incontinence products. The agglutination medium may also be in the form of a powder or particle. Again, the powder or particle can be the agglutination medium alone, or it can be a powder or particle coated with the agglutination medium. The powder or particles may be intermixed with the wood pulp fibers in the web. Also in accordance with the present invention methods are provided for forming a web having improved strength characteristics. In general terms, the agglutination medium, preferably in the form of fibers comprising the agglutination means, is combined with a band of randomly oriented pulp cellulosic fibers which are mutually intermixed. The agglutination medium can be combined with the pulp cellulosic fiber web either by mixing or intermixing the agglutination medium with the pulp cellulosic fibers or by placing layers of the agglutination medium and the web. The solvent for the agglutination fibers is also introduced in the band, which can partially solubilize the surface of the agglutination fibers. By doing so, the surfaces of the agglutination fibers become sticky causing the agglutination fibers to adhere to one another and to the pulp cellulosic fibers. The amount of solvent used is limited, so that it can not completely solubilize the agglutination fibers, and so that it can dissipate to allow the surfaces thereof to solidify again and form a permanent bond with the cellulosic pulp fibers. The solvent can be introduced into the band by first combining it with all or part of the cellulosic fibers. Alternatively, the solvent may be applied by spraying on the web after the binding fibers are in contact with the pulp cellulosic fibers. When the solvent is combined with the cellulosic fibers, the fibers can be stored for a period and can be transported to the place of use before being combined with the agglutination medium. Pulp cellulosic fibers can be wood pulp fibers, or pulp fibers from other agronomic products such as straw, Kenaf or similar material.

BRIEF DESCRIPTION OF THE DRAWINGS A better understanding of the invention can be deduced by reading the following specification in conjunction with the accompanying drawings, in which: Figure 1 is a schematic view of a process for producing the material of the present invention. Figure 2 is a schematic view of another method for producing the material of the present invention. Figure 3 is a schematic view of an absorbent product incorporating the reinforced web produced in accordance with the present invention. Figure 4 is a schematic view of another absorbent product incorporating the reinforced web produced in accordance with the present invention. Figure 5 is a schematic view of another absorbent product incorporating the reinforced web produced in accordance with the present invention. Figure 6 is a photomicrograph of cellulose acetate fibers and cellulose pulp fibers without agglutination. Figure 7 is a photomicrograph showing cellulose acetate fibers bonded to cellulose pulp fibers. Figure 8 is a photomicrograph showing cellulose acetate fibers bonded to one another. Figure 9 is a photomicrograph showing cellulose acetate fibers bonded to cellulose pulp fibers and to superabsorbent particles; and Figure 10 is a photomicrograph which is an amplification of Figure 9 showing the cellulose acetate fibers bonded to superabsorbent particles.

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a reinforced web containing pulp cellulosic fibers, an agglutination medium and a solvent that partially solubilizes the agglutination medium. In a preferred form of the invention, the agglutination medium comprises soluble fibers in the solvent that are unevenly dispersed throughout the cellulose pulp fiber web. In another preferred form of the invention, the fibers soluble in the solvent are dispersed uniformly throughout the pulp cellulosic fiber band. In a third preferred form, the fibers soluble in the solvent are in a layer on one side of the band, preferably the upper side. In a fourth preferred form, the agglutination medium soluble in the solvent is located on the adjoining surface of a band of pulp cellulosic fibers and other material such as a fabric or nonwoven cover material. The solvent can be contacted with the agglutination fibers before, after, and / or during the formation of the band. The amount of solvent is chosen so that at least part of the surface of the agglutination fiber is partially solubilized. When partially solubilized, the surface layer of the agglutination medium becomes sticky. Then, it can flow over the surfaces with which it contacts, including both the agglutination fibers themselves and the pulp cellulosic fibers. As it flows over these surfaces, it moistens the surface. The solvent is applied in an insufficient amount to completely solubilize the fibers and is also applied in an amount such that the solvent is finally dissipated, for example, by being absorbed into the soluble fibers or cellulose fibers of the pulp. Insofar as the solvent is absorbed in the soluble fibers, the concentration of the solvent on the surface decreases and the surfaces of the fibers solidify again. As they solidify again, they bind to each other and to other materials, including pulp cellulosic fibers at the points of contact and wetting. In this way, a strong matrix of pulp cellulosic fibers interconnected with agglutination fibers is produced. The web produced in this manner exhibits a significantly higher dry integrity and, depending on the agglutination medium and the solvent, a higher wet integrity than a web composed solely of pulp cellulosic fibers. An expression of integrity is that the material maintains its structure, shape or conformation under load. Another expression of integrity is the resistance of the wet or dry material.

The cellulosic pulp fibers used in accordance with the present invention are conventionally employed to form a web for use, for example, in absorbent articles. Pulp cellulosic fibers are insoluble in the solvent used to partially solubilize the agglutination medium. A large variety of pulp cellulosic fibers can be used, derived from sources that are wood and non-wood. Wood pulp is more commonly used due to its availability and price. Therefore, cellulosic fibers derived mainly from wood pulp are preferred. The wood pulp fibers suitable for use with the invention can be obtained from well-known chemical processes. The pulp fibers can also be treated by chemical methods, thermomechanical methods, chemo-mechanical methods or combinations thereof. The preferred pulp fiber is produced by chemical methods, either sulfate or sulphite. The preferred starting material is prepared from large fiber conifer species such as southern pine, Douglas fir, oyamel and pinabete. Other chemical pulps made from short or large fiber wood species, ground wood fibers, recirculated or secondary wood pulp fibers, and bleached or unbleached wood pulp fibers may be used. Shortwood fibers are produced from hardwood species, such as eucalyptus, using known chemical procedures, or from any species of wood using mechanical or quimoter mechanical methods. The details of the production of wood pulp fibers are well known to those skilled in the art. Said fibers are commercially available from several companies, including Weyerhaeuser Company, the assignee of the present invention. For example, the suitable cellulose fibers produced from the southern pine which are usable with the present invention are manufactured by Ueyerhaeuser Company, under the designations CF416, NF405, NB416 and CMC518. Straw, linen, kenaf or similar materials can also be used as starting material for pulp cellulosic fibers. The wood pulp fibers of the present invention can also be pretreated before being used with the present invention. This pretreatment may include physical treatment, such as subjecting the fibers to steam, or chemical treatment, for example, entanglement of the cellulose fibers using any of a variety of crosslinking agents such as dirnethyldihydroxyethyleneurea. The entanglement of the fibers, for example, increases their elasticity, and thereby can improve their absorbency. The fibers can be twisted or undulated at will. A suitable interlaced pulp produced from southern pine is manufactured by the Ueyerhaeuser Company under the designation NHB416. Although not constructed as a limitation, examples of fiber pretreatment include the application of flame retardants to the fibers, for example by spraying the fibers with chemical flame retardants. Specific flame retardant chemical agents include, by way of example, sodium borate / boric acid, urea, urea-phosphate, etc. In addition, the fibers can be pretreated with surfactants or other liquids such as water or solvents, which modify the surface of the fibers. These are known as softened or disunited fibers. Other pretreatments include exposure to antimicrobial agents, pigments and densification or softening agents. It is also possible to use fibers pretreated with other chemical agents, such as thermoplastic and thermoplastic thermoset resins. Combinations of pretreatments can also be employed with the resulting pretreated fibers which are subjected to the application of the binder, as explained below. The cellulosic fibers treated with known particle binders and / or desizing / softening aids in the art they can also be used as the pulp cellulosic fibers according to the present invention. Particle binders can be used to bond other materials such as polymers that are sorptive to the cellulosic fibers. The cellulose fibers treated with suitable particle binders and / or densification / softening aids and the process for combining them with cellulose fibers are described in the following United States patents and patent applications: (1) Series No. 07/931, 059, filed on August 17, 1992, entitled "Polymeric Binders for Binding Particles to Fibers"; (2) Series No. 07 / 931,277 filed on August 17, 1992, entitled "Non-Polymeric Organic Binders for Binding Particles to Fibers"; (3) Patent No. 5,300,192, entitled "Uet Laid Fiber Sheet Manufacturing Uith Reactivatable Binders For Binding Particles to Fibers"; (4) Patent No. 5,352,480, entitled "Method for Binding Particles to Fibers using Reactivatable Binders"; (5) Patent No. 5,308,896, entitled "Particle Binders for High-Bulk Fibers"; (6) Series No. 07 / 931,279, filed on August 17, 1992, entitled "Particle Binders that Enhance Fiber Densi ication"; (7) Series No. 08 / 107,469, filed on August 17, 1993, entitled "Particle Binders"; (8) Series No. 08 / 108,219, filed on August 17, 1993, entitled "Particle Binding to Fibers"; (9) Series No. 08 / 107,467, filed on August 17, 1993, entitled "Binders for Binding Water Soluble Particles to Fibers"; (10) Series No. 08 / 108,217, filed on August 17, 1993, entitled "Particle Binders"; (11) Series No. 08 / 108,218, filed on August 17, 1993, entitled "Particle Binding to Fibers"; and (12) Patent No. 5,447,977, entitled "Particle Binders for High-Bulk Fibers", all expressly incorporated herein by reference. An example of a suitable densification / softening aid is a mixture of 70% sorbitol and 30% glycerin. The pulp is treated with sorbitol and glycerin by spraying the pulp sheet with the mixture and passing the sheet through a roller coater, or other means to add a liquid to a pulp sheet, familiar to those skilled in the art. The soluble agglutination medium used in accordance with the present invention can be incorporated with the pulp cellulosic fibers, either in fiber form, or as particles or granules. If desired, the agglutination medium can also be coated on insoluble solvent fibers, such as cellulosic fibers, which can then be distributed throughout the pulp cellulose fiber matrix. It is currently preferred that the agglutination medium comprises a fiber and is mixed with the pulp cellulosic fibers, for example, during the formation of a spongy band, by conventional air-laying processes. The solvents used in accordance with the present invention, of course, must be capable of partially solubilizing the agglutination medium as described above. The solvents must be able to dissipate or partially migrate from the surface of the agglutination medium to allow the agglutination medium to solidify again after partial solubilization. The non-volatile solvents can be dissipated for the most part by absorption in the agglutination medium. It is preferred that the solvent be of limited volatility, so that little or no solvent is lost in the atmosphere. By limited volatility it is understood that the solvent has a vapor pressure of 29 KPa, or less at 25 ° C. By using a limited volatility solvent, the usual precautions necessary to control volatile matters can be reduced, and the amount of solvent required to partially solubilize the agglutination medium can be reduced. In addition, the use of limited volatility solvents can eliminate the concurrent treatment problems encountered with volatile solvents, many of which are flammable and should be handled with caution. The use of limited volatility solvents can also reduce environmental problems. Furthermore, it is convenient that the solvents are not toxic and that they can dissipate from the surface of the agglutination medium without adversely affecting the general strength of the agglutination medium. Preferred agglutination media and solvents of limited volatility are listed in the table below.

Solvent Agglutination Media Cellulose Acetate triacetin Propanediol Diacetate Propanediol Dipropionate Propanediol Propanediol Urate Triethyl Citrate Dimethyl Phthalate Dibutyl Phthalate Cellulose Nitrate Triacetin Cellulose Butylate Triacetin Copolymer Vinyl Triacetin Chloride / Vinyl Acetate Coated Triacetin Cellulose Fibers with polyvinyl acetate Of the different agglutination media listed, cellulose acetate is preferred. During the manufacture of cellulose acetate fibers, a finish is usually applied to the fibers. Many times this finish is in the form of an oil. The presence of finishing sometimes reduces performance as a means of agglutination. The presence of a finish can adversely affect the development and strength of the joints. It has been found that when the agglutination fibers are as straight as possible, as opposed to when they are curled or over-twisted, they provide more contact points with the cellulosic fibers, and in this way the final band will develop better resistance. Similarly, when the agglutination fibers are as long as reasonably possible, the strength of the final band increases. In addition to the above, cellulose ethers and other cellulose esters can also be used as a binder medium. The acetylated pulp fibers can also be used as a binder medium and can be substituted with any number of acetyl groups. A preferred degree of substitution (G.S.) would be 2 to 3, and a G.S. Very preferred would be 2.4. Solvents can be added in different amounts. Resistance is adversely affected if it adds too little or too much solvent. It has been found that at a weight ratio of cellulose acetate / pulp of 10/90, solvents, and particularly triacetin, provide good strength when added in amounts ranging from 6% to 17%, and most preferably in the scale from 9% to 14%, based on the weight of the pulp fiber present. Preferred forms of the solvents diacetate, dipropionate and dibutyrate of propanediol are forms 1, 2 and 1.3. Other suitable solvents working in accordance with the present invention are butylphtalylbutyl glycolate, N-cyclohexyl-p-toluenesulfonamide, dialyl phthalate, dibutyl phthalate, dibylthyl succinate, dibutyl tartrate, diethylene glycol dipropionate, di-adipate. - (2-ethoxyethyl), di- (2-ethoxyethyl) phthalate, diethyl adipate, diethyl phthalate, diethyl succinate, diethyl tartrate, di- (2-methoxyethyl) adipate, di- (2-) phthalate methoxyethyl), dimethyl phthalate, dipropyl phthalate, ethyl o-benzoylbenzoate, ethylphthalethyl glycolate, ethylene glycol diacetate, ethylene glycol dibutyrate, ethylene glycol dipropionate, methyl o-benzoylbenzoate, rnetylphthalethyl glycolate, No & p-tolylethylsulfonamide, o-tolyl p-toluensul fonate, tributyl citrate, tributyl phosphate, tributyrin, triethylene glycol diacetate, triethylene glycol dibutyrate, triethylene glycol dipropionate, and tripropionine. It is also possible to incorporate additives in a band formed in accordance with the present invention. The advantage of incorporating the additives during the formation of the band is that they will also be attached to the matrix by some of the solvents and bound in the matrix by the binding means. This provides a significant advantage since the additives can be dispersed and retained throughout the matrix when desired. For example, the additives can be uniformly dispersed and retained throughout the matrix. Additives that can be incorporated in the matrix include absorbent capacity improving materials such as superabsorbent polymers, sorbents such as clays, zeolites and activated carbon, brighteners such as titanium oxide, and odor absorbers such as sodium bicarbonate. Solvents can also reduce the formation of dust caused by the additives or the pulp itself because a greater part of the fine particles are bound and bonded to the matrix by means of the binder medium. A superabsorbent polymer as used herein is a polymeric material that is capable of absorbing large quantities of fluid to form a hydrated gel. The superabsorbent polymers can also retain significant amounts of water under moderate pressures. The euperabsorbent polymers generally fall into three classes, namely, starch graft copolymers, crosslinked carboxymethyl cellulose derivatives and modified hydrophilic polyacrylates. Examples of such absorbent polymers are the graft copolymer of hydrolyzed starch-acetonitrile, a neutralized starch graft copolymer-acrylic acid, a copolymer of saponified acrylic acid ester-ethyl acetate, a copolymer of hydrolyzed acrylonitrile or acrylate copolymer one, a modified crosslinked polyvinyl alcohol, a neutralized polyacrylic acid of self-interlacing, an interlaced polyacrylate salt, carboxylated cellulose, and neutralized copolymer of crosslinked isobutylene-maleic anhydride. The superabsorbent polymers can be combined with the cellulose fibers and binder medium. It is possible to achieve a combination with 75% superabsorbents by weight based on the total weight of fibers and superabsorbent polymer. It is assumed that higher levels can be achieved. It has also been found that the dry strength of the bonded fiber web can be further increased when superabsorbents are added, first treating the superabsorbents with solvent, for example, triacetin.

Quantities of solvent of the order of two percent (2%) of the final weight of the superabsorbent and the solvent will leave the superabsorbent material fluid. In addition, superabsorbent retention increases in the final band. This increased retention may be due to the binding medium, physical binding (encapsulation), hydrogen bonding or a combination of one or more of the three. A web in accordance with the present invention can be produced in a variety of ways using for example air-laying or wet-laying strip forming techniques known to those skilled in the art. The bands can vary in density from, for example, 0.03 g / cc to 1 g / cc. The amount of binder and solvent used in a particular band can vary greatly depending on the techniques of the process as well as the desired characteristics of the final product. The person skilled in the art will be able to alter the different proportions of materials to achieve a desired result. For example, the binder medium could normally be employed in an amount of one half to twenty percent (0.5% to 20%) by weight based on the amount of pulp cellulosic fiber present to produce a web that can be incorporated into a diaper in which is necessary or convenient an increase in wet and dry strength. When a web is produced to be used as a wet cleaner, the amount of binder medium could be increased from twenty to twenty-five percent (20% to 25%) or more based on the weight of pulp cellulosic fiber present. This higher concentration of binder medium will yield a stronger product that will not tear when used to clean surfaces. The amount of solvent combined with the binder medium will also depend on a variety of other factors, including the method of solvent application, the desired rate of strength development, the desired final strength and other properties of the products such as absorption capacity and of wick effect. In this way, the amount of solvent applied can vary from five tenths of a percent (0.5%) to 25 percent (25%) by weight based on the total weight of cellulose pulp fibers. The solvent can be incorporated into the pulp cellulosic fiber web and the binder medium before, during, or after the formation of the web. For example, the binder, either in the form of fiber or particulate, and the pulp cellulosic fibers, can be combined in a hammer mill and then laid in the air. Then, the solvent can be sprayed on the band. The solvent penetrates the band, makes contact with it and partially solubilizes the binding medium. Then, the solvent is absorbed or otherwise dissipated, allowing the binder medium to solidify again and bind to the pulp cellulosic fibers. This method, however, requires a relatively high level of absorber application to achieve reasonably good band strength.

It has also been found that the order in the combination of binder medium and the solvent with the cellulosic fibers affects the hydrophilicity / hydrophobicity of the final band. For example, adding triacetin to the pulp and then combining the pulp with cellulose acetate produces a final product that is hydrophilic. On the contrary, the addition of triacetin during or after the combination of cellulose fibers and cellulose acetate produces a hydrophobic band. Referring now to Figure 1, a preferred method for combining cellulosic fibers, a binder in the form of a fiber and solvent therefor, is first to produce a wet-laid fiber blend sheet comprising the binder medium and fluffy wood pulp. The wet-laid mix sheet is then fed into a hammer mill 32 between two conventional fluff pulp sheets 34 and 36 in preparation for air-laying the pulp in a web. A conventional brush coater 38 can be used to coat the mixing sheet with solvent just before the mixing sheet enters the hammer mill. The solvent can easily penetrate the mixing sheet because it is relatively thin. The binder fibers are evenly distributed in all the cellulose fibers of the pulp of the spongy leaf and the mixing sheet, through the hammer mill. The resulting mixture of cellulose fibers and binders is subsequently passed through a screen, transported by air through a conduit 40, and deposited as a web 42, either on a porous wire or wire 44. When the surfaces of the binder fiber is >; They dissolve slowly, the viscosity of the fiber is minimal and the agglutination does not occur until after the fibers are laid to the air in a band. A vacuum is applied to the back of the wire 44 through a vacuum box 46 to attract the pulp cellulosic fibers and the binder fibers thereto. The solvent then begins to solubilize the surfaces of the binder fibers, allowing them to flow and make contact with the pulp fibers. Once the solvent dissipates as it is completely absorbed by the binder fibers, the surfaces re-solidify, forming a binder matrix for the pulp fibers. Referring to Figure 2, a preferred method for combining pulp cellulosic fibers, a binder in the form of a fiber, and a solvent therefor, is to apply the solvent to a pulp sheet 50 while it is formed or after what is formed. If a preferred solvent of limited volatility is employed, the pulp sheet may then be transported and / or stored for a period before use. Another pulp sheet 52 containing the binder fibers can be prepared on a paper machine by wet suspension of the binder fibers with the pulp fibers at the wet end and forming the fibers into a mixed pulp sheet. The binder fibers are distributed throughout the pulp sheet. The pulp sheet 50 containing the solvent can then be fed to a hammer mill 54 with the pulp sheet 52 containing the binder fibers in preparation for air-laying the pulp in a web. The hammer mill uniformly mixes the fibers containing the solvent with the binder fibers. The resulting mixture of cellulosic fibers and binders is passed through a screen, transported by air through a conduit 56, and deposited in a band 57, either on a porous wire or fabric 58. Upon this occurrence, the solvent begins to transfer to the binder fibers from the cellulose fibers. A vacuum is applied to the back of the wire 58 through the vacuum box 60 to draw the cellulosic fibers and the binder fibers thereto and form a compact web. In a manner similar to the above method, the solvent solubilizes the surfaces of the binder fibers, allowing them to flow and be in contact with the pulp fibers and with each other. Once the solvent is completely absorbed by the binder fibers, the surfaces solidify again, forming a binder matrix for the pulp fibers. Although the above-described preferred methods employ a hammer mill to mix and defibe the fibers, other crushing and defibration devices, such as for example a pin mill or a garnet roller, can also be employed. The mixing can also be carried out separately from the defibration, as in the conduit 56. The mixing sheet 30 referred to in Figure 1 and as 52 referred to in Figure 2, can be wet laid, for example, on a machine. of paper. As an example, a mixing sheet of fifty percent (50%) of binding fibers and fifty percent (50%) of spongy wood pulp can be formed on a paper machine, for example, at a basis weight of 150 grams per meter square (gmc). The amount and type of binder fibers and pulp fibers can vary greatly. For example, binder fibers blended with a bicomponent ther op lastic fiber can be used as a temporary binder to produce a blend sheet that does not contain pulp fibers. Temporary binders such as cooked starch at higher binder fiber contents may also be used to provide sufficient integrity to the mixing sheet during its treatment. A bonded web can also be wet laid. First, a cellulose acetate / pulp mixture is formed on a paper machine. Triacetin can be sprayed onto the underside of the band as it leaves the paper machine. After, the band can enter a honeycomb dryer, for example. The triacetin is attracted through the band in the dryer, distributing the triacetin uniformly, and in this way causing a stronger band to be formed. During formation of the web in accordance with the preferred method, the rate of development of agglutination can be controlled by varying the temperature of the blend sheet, the amount and type of finish on the binder fibers, the hydrophobicity or hydrophilicity of the binder fibers, the order and the time in which the materials are added in the band forming procedure, the forward distance of the hammer mill to which the solvent is applied, the feed rate of the mixing sheet, the amount and type of solvent applied, the temperature of the solvent when applied, and the size of the solvent drops when applied (if the solvent is sprayed directly on the band). The binder medium can also be pre-laminated to increase the rate of agglutination development. After the band is formed, the rate of agglutination development is controlled by the temperature of the formed band (the higher the temperature, the polymeric material will absorb the solvent more rapidly) and the density of the formed band. The hot or cold embossing of the formed band will also produce immediate agglutination in addition to increasing and improving the number of joints. In the preferred methods indicated above, the binder and the solvents are added at specific points in the process. The skilled person will readily understand that the binder and the solvent can be combined at different times and localized in the manufacturing process and / or in the formation of absorbent articles, provided that the binder, the solvent, and the fibers are in intimate contact when agglutination occurs. For example, as shown in Figure 1, cellulose acetate fibers can be mixed with wet pulp at the wet end of the paper machine forming the mixing sheet. The solvent can then be combined with the pulp before, during, or after fiber is made, for example in the hammer mill, duct 40 or wire 44. Similarly, cellulose acetate or other binder medium can be added at any step of the production process before the desired agglutination takes place. Additives such as superabsorbent polymer can be fed into the air laying system after the hammer mill at a point where good mixing occurs between the solvent-treated binder medium and the superabsorbent polymer. Similar to the agglutination between the cellulosic fibers and the solvent-treated binder medium, a weak capillary bond is formed between the solvent-treated binder medium and the superabsorbent polymer, sufficient to retain the superabsorbent polymer in the wet matrix during air-laying. . Insofar as the solvent is absorbed by the binding medium in the course of time, a strong solid bond develops between the superabsorbent material and the binder medium. A variety of suitable structures can be made from cellulose bands formed in accordance with the present invention. The most common are user-absorbent products such as diapers, feminine hygiene products such as feminine pads, and incontinence products for adults. For example, referring to Figure 3, an absorbent article 10 comprises an acquisition layer 12 and an underlying storage layer 14. A liquid-permeable front sheet 16 rests on the acquisition layer 12. Throughout this description, the layer 12 is referred to as an acquisition layer and it should be understood that the acquisition layer 12 can also serve as a distribution layer, that is, it distributes fluid from the discharge zone. A liquid-impermeable back sheet 18 holds the storage layer 14. If desired, the acquisition layer 12 may contain a reinforced layer of cellulosic fibers formed in accordance with the present invention, for example by partially solubilizing the cellulose acetate with triacetin. The cellulosic fibers can be interlaced fibers. The reinforced band provides a strong acquisition layer 12 for use in diapers, for example. The agglutination in the acquisition layer helps maintain its capillary structure, thus helping the transport of fluid in multiple wet conditions. The storage layer 14 can similarly contain a reinforced band of cellulose fibers formed in accordance with the present invention. In the storage layer 14, however, additives such as superabsorbent polymers can also be incorporated to significantly increase the absorbent capacity of the storage layer 14. The superabsorbent polymer is distributed throughout the storage layer 14 and can be bound to the binder medium. during the formation of the band. In this way, the superabsorbent polymer remains distributed throughout the storage layer 14 during handling, and can not fall to the bottom or to the storage layer 14 and thus lose its effectiveness. The article of Figure 3 can be assembled so that the acquisition layer 12 comes into contact with the storage layer 14 while the binder means in it is still active, that is, it is partially solubilized. This allows the storage layer to attach to at least the lower surface of the acquisition layer 12. Using the present invention in this manner eliminates the need to use hot melt gums to join adjacent layers. Stronger agglutination can be achieved between the acquisition and storage layers by incorporating some binder in the acquisition layer at a location that allows it to bind with the binder in the storage layer. The layer 14 can also be attached to the backsheet 18 by supporting the storage layer 14 on the backsheet 18 while the binder means is still active. Similarly, the acquisition layer 12 can be attached to the front sheet 16 by supporting the front sheet on the acquisition layer 12 while the binder means therein is still active. The interlayer bonding can facilitate the transport of fluid through the abutting surface of the layers. The acquisition layer 12 can also be formed of interwoven or non-interlaced cellulosic fibers, which are not joined in accordance with the present invention. The acquisition layer may also be a non-woven web of polyester fibers, bi-component or polypropylene in which part of the binder means has been incorporated, such as cellulose acetate fibers. In each of these structures, including the structure in which the acquisition layer is formed in accordance with the present invention, the storage layer 14 will be joined to the acquisition layer 12, aiding the transport of the liquid from the acquisition layer. towards the storage layer and also gives integrity to the entire structure. The structure in Figure 3 is shown for the purpose of exemplifying a typical absorbent article, such as a female diaper or towel. An expert may be able to make a variety of different absorbent structures using the concepts taught herein. For example, a typical construction for an adult incontinence absorbent structure is shown in Figure 4. The article 20 comprises a front sheet 22, a storage layer 24, formed of a reinforced cellulosic web made in accordance with the present invention, and a backsheet 28. The front sheet 22 is permeable to liquid while the back sheet 28 It is impervious to liquid. In this structure, the cellulosic band is formed on a fabric permeable to the liquid 26. The fabric 26 is composed of a polar fibrous material. The binder used to make the storage layer 24 will also cause the layer to adhere to the fabric 26. If desired, a wicking sheet or layer 30 may be interposed between the front sheet 22 and the fabric 26 to accelerate the distribution of the fabric. liquid through the entire storage layer 24. Referring to Figure 5, another absorbent article includes a dorsal sheet 78, a storage layer 76, an intermediate layer 74 formed in accordance with the present invention, an overlying acquisition layer 72 and a front sheet 70. The intermediate layer 74 contains, for example, acetate of cellulose and triacetin, which are combined just before forming the article. The intermediate layer 74 in this manner can join both acquisition layers 72 and the storage layer 76 to form an absorbent article with much greater integrity than one in which the distribution and acquisition layers are not mutually bonded. The hydrophilicity of the layer 74 can be adjusted in such a way as to create a hydrophilicity gradient between the layers 72, 74 and 76. It should be understood that an independent intermediate layer is not required to obtain a layer-to-layer bonding in accordance with the present invention . When one of the two adjacent layers or both layers contains the binder medium useful in the present invention, if the two layers are put together when the binder medium is still active, the bond between the two layers will occur and provide a stronger mixed body in the two layers. comparison to if the union does not happen. Other articles that can take advantage of the integrity of the increasing properties of the present invention include cleaners, fabrics, towels and filters. Glass fiber filters can also be reinforced using the agglutination method of the present invention. It is also possible to produce a wrapping string that can also be dispersible in water. The articles formed by this invention can be used in those applications in which thermoplastic articles, such as hot filter oil, can not be used.

EXAMPLES The following examples are inserted to instruct the expert on how to make and use the invention. The examples are directed to different embodiments of the invention and it is not intended in any way to limit the scope of the Patent Title granted thereon.

EXPERIMENTAL PROCEDURES FOR EXAMPLES 1 AND 2 The cellulose fibers used in the following examples are southern pine bleached kraft pulp available from Weyerhaeuser Company and are referred to by the designation NB 416. The bleach is elemental free chlorine. The fibers are bleached with chlorine dioxide. The discontinuous fiber of cellulose acetate used in the examples is 1.8 denier by 30.5 cm, 0.64 cm long with coconut oil finish or 1.8 denier by 30.5 cm, 0.32 cm long with a ST-90 mineral oil finish available from Hoechst Celanese. The interwoven fluff pulp fiber is NHB 405, manufactured by Weyerhaeuser Co. The superabsorbent particles (PSA) are IM-3900 from Hoechst Celanese Co. The solvents used are triacetin or industrial grade dimethyl phthalate, available from Aldrich Chemical Company. On a first afternoon, pulp sheets of NB 416 were treated with solvent. In Example 1, five percent (5%) by weight of solvent was sprayed based on the weight of the pulp, on one side of the sheet. Then the sheet was turned over, and five percent (5%) of solvent by weight of the pulp was sprayed on the other side. In Example 2 different amounts of solvent were used as indicated. Afterwards, the leaves were kept overnight. The next day, solvent-treated NB 416 pulp sheets were broken by hand in small pieces of 1.27-1.92 cm and placed in a laboratory-sized Uaring Blendor mixer. To this, 0.31 cm, 1.8 denier by 30.5 cm, was added of discontinuous fiber of cellulose acetate of Hoechst Celanese except in the control. S? Perabsobent particles were also added. The Waring Blendor mixer was fired at low power for 5 seconds to defibe the pulp and mix the pulp and the cellulose acetate fibers together and the particles. A further advantage of the invention was observed during the fibration, namely, the dust and fibers normally produced in the presence of the solvent were greatly reduced. All the absorbent pads were formed in the laboratory on a sheet of cloth in a conventional 15.2 cm diameter circular laboratory pads mold. The pad mold was equipped with a pin mill overrun device. The pulp mix from the Warign Blendor mixer was quantitatively transferred to a vessel. From there, small masses were individually fed into the pad mold. The formed pads were carefully removed from the pad mold by removing the cloth on which the pads were formed and placed in a cold press. A Teflon block with a 15.2 cm diameter hole cut on the pad was placed. A teflon plug was placed on the pad and the pad was cold pressed to achieve the desired pad density for 1.1-1.3 minutes.

The pads were removed after the cold press and four pads were stacked, one on top of the other. Sufficient weight was placed on the four pads to crush the pads to a predetermined caliper. Chocks were used to support the applied weight and maintain the desired caliber. The pads were allowed to cure at room temperature under this weight for a period of at least two days. Test pads were then cut 10.2 by 10.2 cm from each of the circular pads. The aqueous solution used in the tests is a synthetic urine available from National Scienti ic under the trademark RICCA. It is a saline solution that contains 135 meq / 1 of sodium, 8.6 meq / 1 of calcium, 7.7 meq / 1 of magnesium, 1.95% of urea by weight (based on total weight), plus other ingredients. An absorbent capacity test was carried out on a test pad by recording the dry weight of the initial sample (Ui) in grams. The test pad was then placed on a wire support screen and immersed in synthetic urine in a horizontal position. If the pad contains superabsorbent particles, the pad is immersed for 30 minutes. If the pad does not contain any superabsorbent particles, the pads are immersed for 10 minutes. The pads were removed from the synthetic urine solution and allowed to drain for 5 minutes. Afterwards, the pads were placed under a load of 0.07 kg / cm2 for 5 minutes. The wet pad is reweighed (W2) in grams. The total capacity under load is reported as 2 -Wi. The capacity unit under load is calculated by dividing the total capacity between the dry weight, (W2 -W1 / W1). If the test pads contain a solvent, the weight of the solvent is not included in the p >That dry. A tensile integrity test of the dry pad was performed on a 10.2 by 10.2 cm test pad by securing a dry test pad along two opposite sides. Approximately 7.5 cm of the length of the pad between the fasteners is visible. The sample is pulled vertically on an Instron test machine and the measured tensile strength is reported in N / m. The tensile strength is converted to the tensile index, Nm / g, by dividing the tensile strength by the basis weight g / m2. A wet traction integrity test was carried out by taking the sample from the total capacity test and placing the sample in a horizontal boat. Opposite ends of the sample are held and oppositely pulled horizontally on the Instron test machine. The wet tensile strength, N / m, is converted to tensile index, Nm / g, dividing by the base weight of the sample, g / m2.

EXAMPLE 1 15.2 cm diameter pads with the following composition were made in the pads former of the laboratory. The percentage indicated after the weight of PSA is the percentage of PSA in the test pad based on the total weight of the pad.

No. Sample Composition Total Weight Control 6.05 NB 416 1 .0 g 3.95 PSA (39.5%) Fiber 100% 5.75 NB 416 agglutinated 0.30 g cellulose acetate 10.0 g 2/3 fiber 3,375 g NB 416 agglutinated 0.20 g cellulose acetate 3.95 g PSA (52.5%) 7.5 g 1/2 fiber 2.61 g NB 416 agglutinated 0.15 g cellulose acetate 6.7 g 3.95 g PSA (59%) After forming the pads with the above composition, and storing at a prescribed density for 3 days, 5 pads were tested for each composition with the following results: Sample Density Traction Index Absorbent Capacity # g / cc Nm / g Dry Total Wet (g) Unit (g / g) 1 0. 17 0. 02 0 72. 5 14. 4 2 0. 18 0. 15 0.049 74. 3 14. 4 3 0. 14 0.08 0. 032 65.5 17. 6 4 0. 13 0. 04 * 64 .8 19. 7"Integrity of the wet pad exhibited, but the sample was so swollen that it could not be tested with the fastener system.

Example 1 illustrates that the superabsorbent particles, at a concentration higher than that normally used in commercial diaper absorbent cores, can be incorporated into a spongy pulp pad bonded with this technology. The example also illustrates that the cellulose acetate discontinuous fiber agglutinated pads developed good wet and dry strength integrity, even though some of the pads were composed of more than 50% superabsorbent particles. This example also illustrates that even with the removal of more than 50% of the fiber compared to the control, the total capacity of the pad under load decreased by only about 10%. Although the total absorbent capacity of the pad under load decreased, the unit absorption capacity increased. Electron micrographs indicate that the superabsorbent particles are well bonded to the cellulose acetate fibers which in turn are tightly bound to other pulp or cellulose acetate fibers in the pad.

EXAMPLE 2 This example illustrates that dimethyl phthalate can be used to activate agglutination in place of triacetin. As in Example 1, sheets of fluffy pulp of NB 416 were treated with 5, 15 and 30% by weight of triacetin, based on the weight of the pulp. Additional pulp sheets were treated with 5, 15 and 30% by weight of dimethyl phthalate, based on the weight of the pulp. The pulp sheets were defibrated in the Waring blender and then 10% by weight of cellulose acetate was added to the blender, based on the weight of the pulp. The following pulp mixtures were made: Level of Sample Level Phthalate level of acetate «Triacetin,% dimethyl,% cellulose,% 1 (Control 0 0 0 2 15 0 0 3 0 15 0 4 5 0 10 5 15 0 10 6 30 0 10 7 0 5 10 8 0 15 10 9 0 30 10 The wet and dry tensile strength of the pads was tested with the following results: Sample # Traction Index, Nm / g Dry Humid 1 0. 11 0.056 2 0.05 0.039 3 0. 05 0.042 4 0. 04 0.042 5 0. 44 0.180 6 0. 14 0.23 7 0 0..3366 0.15 8 0. 44 0.166 9 0. 37 0.132 EXAMPLE 3 This example illustrates that a non-softened version of interlaced NHB 405 fluff pulp fiber (manufactured by Weyerhaeuser) which has been laid in the air can be bonded to structures having superior tensile strength of the wet and dry pad. This example also illustrates that changing the cut length of cellulose acetate from 0.33 cm to 0.63 cm improves the wet tensile strength compared to the control sample containing cellulose acetate fiber that was not activated by a solvent. The interlaced fiber was not treated as in Example 1 because it was not in the form of a leaf. The interlaced fiber was first treated separately in a mini-mixer with different levels of cellulose acetate. Then, different levels of triacetin were sprayed into the mixer while the mixer was in motion. The following pad compositions were made in the 15.2 cm pad mold as in Example 1: Acetate Acetate Sample cellulose 1 / cellulose Ni, # triacetin,% 0.63 cm (%) 0.31 cm (%) 1 0 10 0 2 5 2.5 0 3 5 5 0 4 0 0 10 5 5 0 2. 5 6 5 0 5 The pads were cold compressed and stored for 2 days under pressure so that the density of the final pad was approximately 0.09 g / cc. After 2 days, 10 x 10 cm test samples were treated to determine wet and dry tensile strength. Sample # Traction index, Nm / g Dry Humid 1 0.026 0.034 2 0.073 0.065 3 0.166 0.100 4 0.020 0.024 5 0.078 0.033 6 0.114 0.035 EXAMPLE 4 This example illustrates that the cellulose acetate fiber can be incorporated into a pulp sheet and the cellulose acetate plasticizer can be incorporated into another separate pulp sheet. When both sheets are fed into a hammer mill simultaneously and tend to air in a band, agglutination occurs.

Experimental Procedure 20% by weight of discontinuous fiber of cellulose acetate, 1.8 denier by 30.5 cm, 0.31 cm, of ST-90 finish from Hoechst Celanese (based on the dry weight of the pulp and the combined cellulose acetate) was suspended in water. ) with pulp NB 416. Then, the pulp suspension was wet laid on a Noble »Wood pilot paper machine on one sheet, base white weight 300 g / m2 and dried to approximately 6% moisture content. For cylinders treated with solvent, a pulp cylinder of NB 416, base weight 750 g / m2, was unrolled, 6% moisture content, and triacetin was sprayed at 20% by weight based on the weight of the pulp on one side. After spraying, the pulp sheet was immediately rewound. Two sheet cylinders of the cellulose acetate pulp / NB 416 pulp mix formed above and a cylinder of the triacetin treated with NB 416 pulp formed above were introduced into the hammer mill. All the sheets were simultaneously fed into the hammer mill. The hammer mill defibrates the pulp sheets into individual fibers. From the hammer mill, the defibrated pulp is transported to the head of a DanWeb air-laying machine. A white basis weight was 300 g / m.2. The wet samples were cold calendered immediately to a position of 2.8 kg / cm2. After settling one hour, the band samples were passed through the band calender again in the same position. The density of the band was approximately 0.090 g / cc. The composition of the final band was approximately 11% triacetin and 9% cellulose acetate, based on the dry weight of the pulp fiber. The band samples were allowed to cure for 2 days at room temperature and the wet and dry tensile strength was measured as in example 1.

Density tensile index, Nm / g Sample g / cc Dry Humid Control 0.089 0.058 0.053 Agglutinated band of cellulose acetate 0.098 0.233 0.176 EXAMPLE 5 This example illustrates that high concentrations of superabsorbent particles can be incorporated in a bonded band laid in the air.

Experimental Procedure To the air-laid strip produced as in example 4, PSA (Hoechst Celanese IM 3900) was added at 450 g / m2, with a spray nozzle, in the formation head of the Danweb air-laying machine .

Results A sodium analysis showed that the agglutinated band was composed of 62% superabsorbent polymer and 38% pulp fiber and cellulose acetate. The superabsorbent polymer was well bonded, as shown by electronic icrographs, and does not easily exit the band. A similar control pulp with the same amount of superabsorbent particles but no binding fibers exhibited poor integrity of the pad and the absorbent particles easily left the pad. The bound cellulose acetate band was held together when the band was placed in synthetic urine for 30 minutes and the superabsorbent particles were swollen. The similar control pad completely disintegrated. The following dry tensile strengths and absorption capacity under load were measured as in example 1.

Sample tensile index, Absorption Capacity, Nm / g g / g Control 0.091 20.46 Cellulose acetate agglutinated band 0.123 20.71 EXAMPLE 6 This example illustrates the impact of the level of solvent on the development of strength when the discontinuous fiber of cellulose acetate remains constant. The resistance goes up to an optimum. It is thought that at lower amounts of solvent, cellulose acetate forms fewer bonds with a smaller bond surface area. To the extent that more solvent is added, the number and surface area of the links increases and the band becomes stronger. Even at higher levels of solvent, the cellulose acetate fiber becomes weaker and the band resistance decreases.

Experimental Procedure A load of a defiberized non-softened version of interlaced NHB 405 pulp fiber (manufactured by Weyerhaeuser Company) and a defibrated NB 416 load (bleached pulp fiber) was mixed with 10 wt% cellulose acetate (1.8% by weight). denier by 30.5 c, 0.63 cm finished coconut oil from Hoechst Celanese.} in a mixer.

The non-softened mixture of NHB 405 / cellulose acetate was divided into 4 parts. One part was kept as a control, the 3 parts were sprayed with 10%, 20% and 30% triacetin, respectively, based on the weight of the pulp, while stirring in the mixer. The mixture of NB 416 / cellulose acetate was also divided into 4 parts. One part was kept as a control and the other 3 parts were sprayed respectively with 5, 15 and 30% triacetin, based on the weight of the pulp. The following results were obtained: Density level tensile index, Nm / g Triacetin fiber,% g / cc Dry Humid NHB 405 without 0 0.064 0. 026 0.034 softening / cellulose acetate 0. 080 0.199 II 10 0.137 0.082 0.176 0.254 II 20 30 0. 085 0. 125 0.205 NB 16 / acetate 0 0. 114 0.052 0.069 cellulose II 5 0.123 0.385 0.182 II 15 0. 121 0.561 0.519 II 30 0.136 0.354 0.361 EXAMPLE 7 This example illustrates that it is possible to develop agglutination with other types of fibers that are softened or solubilized by a solvent. In this example, vinyl chloride / vinyl acetate copolymer fibers (MP-Faser fibers, 3.3 dtex / 12.5 mm from Wacker Chemicals (USA) Inc.), 20% by weight based on the weight of the pulp, were mixed. with some NHB 405 interlaced pulp fibers without softening, defibrated. The NHB 405 had previously been treated with triacetin at 30% by weight based on the weight of the pulp. The two fibers were mixed together in a Uaring laboratory mixer, at low speed for 30 seconds. The mixture was then fed slowly into the pad mold as in Example 1 to produce a uniform 15.2 cm diameter pad of approximately 500 g / rn.2 basis weight. Subsequently, the pad was compressed on a Wabash laboratory press for 1 minute and 30 seconds to produce a 0.1 g / cc pad. Then, the pad was stored under a 1.35 kg plate. Significant agglutination occurred on the pad when the pad was checked again at 24 hours.

EXAMPLE 8 This example illustrates that very little triacetin is required to activate the agglutination when the triacetin can be directed to the cellulose acetate fibers. A pulped wet pulp and cellulose acetate sheet having a basis weight of 150 g / m2 was made on a Noble and Wood paper pilot machine. The sheet was composed of 75 g / m.2 of discontinuous fiber of cellulose acetate, 1.8 denier by 30.5 cm, 0.63 crn, finished coconut and 75 g / m2 of spongy pulp NB 416 slightly refined. Two pulp cylinders NB 416 having a basis weight of 750 g / m 2 were mounted on bras and a tail of each cylinder was fed into a hammer mill. The mixing sheet, which contained 50% discontinuous fiber of cellulose acetate was mounted on a bra placed between the two cylinders NB 416, and a tail was fed into the hammer mill between the two sheets of pulp NB 416. The triacetin, 17.2% by weight based on the weight of the mixing sheet, was uniformly sprayed only on the cellulose acetate mix sheet on one side, between the hammer mill and the mounting bracket. Because the sheet of the mixture was only 150 gsm, the triacetin quickly penetrated through the sheet. In the hammer mill, the three leaves were defibrated and mixed together. The mixed defibrated pulp was transported from the hammer mill to the forming head of a Danweb air-laying machine, where it was laid in a band. The band formed in the course of 30 to 60 minutes afterwards, evident agglutination occurred in the pulp sheet. The band laid to the final bound air had a composition of 1.6% triacetin, 4.5% cellulose acetate and 93.9% fluff pulp NB 416.

EXAMPLE 9 This example illustrates that the pulp / cellulose acetate pad does not bind to other substrates that are in contact with the pad while agglutination develops. This is important since it is often important to have the absorbent core in intimate contact with tissue and non-woven covers that are also used in absorbent products. Several air-laid strips were made, 180 g / m2 of basis weight on a Danweb air-laying machine. The bands were composed of an NHB 405 interlaced pulp without softening with 10% by weight, based on cellulose acetate fiber pulp (Hoechst Celanese, 0.33 cm, 1.8 denier by 30.5 cm, CS-90 finish). Triacetin (8% by weight based on pulp fiber) was sprayed onto the pulp mixture in the Danweb transport fan. After fabrication, the air-laid strip is cut into rectangular pieces measuring 45x35 cm. The pieces were stacked in two stacks of 200 high with a non-woven latex bonded sheet between each sample. A piece of corrugated cardboard was placed on both stacks of samples. A uniform weight, 113.40 kg or 0.04 kg / cm, was placed on the piles and samples were allowed to develop pad agglutination at room temperature for a period of 5 days. When the weight was removed, the upper band exposed to the air of each pile was well attached to the surface of corrugated cardboard that was in direct contact with the band lying in the air.

EXAMPLE 10 Variations of the hydrophilicity / hydrophobicity of the soluble binder medium in the solvent can be used to take advantage of absorbent products. This example illustrates that it is possible to make a low density agglutinated pad that absorbs like wick and moistens well, but does not require any surfactant. In the normal treatment of cellulose acetate fibers, oils are added to the cellulose acetate to lubricate the fibers. This reduces friction from fiber to fiber and fiber to metal and this in turn reduces fiber breakage. Because of this, cellulose acetate is hydrophobic until its surface becomes moist. Therefore, the surface acts as a hydrophilic surface. The hydrophobicity of air-laid pads was observed when cellulose acetate fibers having a mineral oil or coconut oil finish were used. The hydrophobicity was particularly pronounced when the mixing time was prolonged, when the triacetin level increased, or when the curing temperature was raised. In this example, cellulose acetate fibers (Hoechst Celanese 3.1 cm, length of 3.1 cm, 3.0 denier by 30.5 cm), made with a water lubricant, were cut with scissors into smaller fibers of approximately 0.63 cm. The cellulose acetate fibers were then mixed, 10% by weight based on the pulp, with a NB 416 pulp which had been previously treated with 15% by weight of triacetin based on the pulp. The mixture of fluff pulp / cellulose acetate was then made in a 10 g pad on the 15.2 cm pad mold as in Example 1. Next, the pad was compressed to a density of about 0.1 g / cc. A portion of the pad was removed and allowed to cure in a 105 ° C oven for 3 days. The rest of the pad was allowed to develop agglutination under light pressure (0.02-0.03 kg / cm2) for 3 days. Both samples, cured in the oven and cured at room temperature, developed good pad integrity. The samples exhibited hydrophilic properties. A water drop test immediately wet both samples and absorbs liquid by wicking away from the point of impact. There was no apparent hydrophobicity of the cellulose acetate fiber. By varying the finish on the cellulose acetate and varying the amount of cellulose acetate used, the hydrophobic / hydrophilic nature of the product can also be altered.

EXAMPLE 11 This example illustrates that while the ambient temperature is sufficient to develop agglutination, increases in temperature during agglutination are beneficial in developing a stronger level of agglutination more rapidly. Interlaced pulp was treated without softening NHB 405 with 10% triacetin, by weight based on the pulp, in a Waring blender. The cellulose acetate coconut oil (Hoechst Celanese, 0.63 cm, 1.8 denier by 30.5 cm) was mixed with the solvent-treated interlaced pulp so that the final compositions contained 10% by weight of cellulose acetate fiber. The mixture was converted into 15.2 cm pads with the lab pads mold having a basis weight of approximately 55 g / rr »2. The pads were cold pressed to a density of approximately 0.1 g / cc. A group of pads was allowed to cure, at a constant caliber for 90 hours. One hour after manufacture, another group of pads was placed in a 50 ° C oven for 90 hours. The caliber was also constant. One hour after manufacture, a third group of pads was placed in a 100 ° C oven for 90 hours at constant gauge. The pads were removed from each group after one hour, four hours, 20 hours and 90 hours and the dry tensile strength was measured.

Tensile Strength, N / m Temprature 1 hour 4 hours 20 hours 90 hours ° C 24 24 208 243 50 ° C 235 289 353 422 100 ° C 410 548 667 739 The results show that by raising the temperature 30 °, the tensile strength is almost equal to the tensile strength developed at 20C, C after 90 hours. At 100 ° C, the tensile strength greatly exceeded the tensile strength obtained at room temperature in 90 hours. After 90 hours, the sample cured at 100 ° C is almost three times as strong as the sample cured at room temperature.

EXAMPLE 12 This example shows that the ability to absorb synthetic urine is not adversely affected by the agglutination of cellulosic fibers in a band in accordance with the present invention. Round 15.2 cm test pads were created in a conventional manner using NB 416 pulp and cellulose acetate fibers (6.63 cm, 1.8 denier by 30.5 cm). A mixture of 10% by weight of cellulose acetate and 90% by weight of NB 416 was used. After the fibers were mixed, 10% by weight of triacetin was added based on the weight of the pulp. Super absorbent polymer (PSA) was also added. Test pads containing 50% by weight, 60% by weight and 70% by weight of superabsorbent polymer were prepared based on the weight of the pulp. Control pads containing 50%, 60% and 70% by weight of PSA were also prepared, omitting the solvent and the cellulose acetate. The pads were then tested to determine their absorption capacities by immersing them in synthetic urine for 30 minutes. Then the pads were allowed to drain. Then, the pads were weighed and inserted into a centrifuge for 75 seconds. The pads were weighed again to determine their dry weight. The absorption capacities were then calculated on the basis of grams of urine absorbed per gram of dry weight of pad. The results are indicated in the following table.

CONTENT 50% g / g 60% g / g 70% g / g DE Capacity Capacity Capacity Total PSA (g) Total (g) Total (g) Control 89 10.6 149 14.2 249 17.7 Agglutinated 95 10.5 159 13.6 247 16.9 The results show that the agglutination slightly reduced the gram absorption capacity per gram, but the total capacity of the pad remains approximately the same with different PSA loads.

EXAMPLE 13 The purpose of this example is to illustrate that the order of addition of the solvent and the binding medium to the pulp significantly alters the development of resistance and hydrophobicity of the resulting pad. The combination of solvent with the cellulose fiber and then the mixing with binder fibers produced a relatively strong and hydrophilic bound band. Mixing the binder fibers first and then adding the triacetin produced a bonded band with lower strength and which was relatively hydrophobic. 15.2 cm test pads containing 10% cellulose acetate (0.63 cm length) were prepared, 1.8 denier per 30.5 cm) and 90% cellulosic fibers (non-softened version of NHB 405), in a conventional manner. A first sample A was formed by first adding 10% by weight based on the weight of triacetin pulp to the pulp. Then 10% cellulose acetate (based on the combined weight of the pulp and cellulose acetate) was added and the resulting mixture was stirred. Sample B was formed by first adding cellulose acetate (10% by weight) to the pulp (90% by weight) and mixing that combination, and then adding triacetin and mixing the combination again. Both sample pads contained 10% by weight of triacetin based on the weight of the pulp. Wet and dry tensile integrity tests were developed and a traction energy absorption and tensile index was calculated. The tensile energy absorption is the area under the curve of the tensile strength against the stretch before breaking. Hydrophobicity was tested by placing a sample on the surface of synthetic urine. The float time was then measured. A long float time indicates that the pad is hydrophobic. These results are indicated below.

Order of Resistance Float time addition (sec) Dry Humid IT (Nm / g) AET (J / m2) IT (Nm / g) AET (J / m2) A 0.48 67 0.25 36 0-1 B 0.36 54 0.21 33 17 It was observed that the lower resistance of pad B is probably caused by a poor distribution of triacetin. In addition, the hydrophobicity of pad B is likely caused by the smearing of dissolved cellulose acetate onto the pulp fiber surfaces during the manufacture of the pad.

EXAMPLE 14 The purpose of this example is to illustrate that corrugated cellulose acetate fibers provided a pad of less strength than straight fibers when treated in another manner in accordance with the present invention. First the pulp NB 416 was treated with 10% by weight of triacetin based on the weight of the pulp. Then, it was combined with cellulose acetate in the ratio of 90% by weight of pulp to 10% of cellulose acetate (0.63 cm). Several 15.2 cm test pads were produced in a conventional manner using cellulose acetate that had no ripple (2.0 denier per 30.5 cm), a slight undulation (1.8 denier per 30.5 cm, 4-6 undulations per 2.5 cm) and a high ripple. undulation (1.8 denier X 30.5 cm, 20-24 undulations per 2.5 cm). Then wet and dry tensile integrity tests were performed and the tensile index and tensile energy absorption were calculated. The results are indicated below: Cellulose Acetate Ripple None Light (4-6) High (22-24) IT (Nm / g) 0.74 0.48 0.37 Dry IT (Nm / g) 0.52 0.25 0.18 Wet AET (J / m2) 71 36 38 The results illustrate that when corrugated cellulose acetate was used, the resistance in the pad decreased dramatically. It is believed that this is due to a reduction in the number of contact points between the cellulose acetate fibers and the cellulose fibers.

EXAMPLE 15 The purpose of this example is to illustrate that the strength of a pad, formed in accordance with the present invention, increased with the length of the cellulose acetate fibers employed. 15.2 cm pads were formed in accordance with the present invention. NB 416 pulp fibers were treated first with 10% by weight of triacetin based on the weight of the pulp fibers. The pulp was then combined with cellulose acetate to form a band containing 90% by weight of pulp and 10% by weight of cellulose acetate. Several samples were formed using 3.75 denier by 30.5 cm cellulose acetate fibers, with lengths ranging from 0.33 cm to 1.25 cm. Then, wet and dry tensile strength integrity tests were performed and the traction energy absorption tensile index was calculated. The results are indicated in the table below. 0. 33cm 0.63 cm 0.94 c 1.25 cm Dry IT 0.21 0.32 0.34 0.42 AET 30 45 64 80 Wet IT 0.10 0.22 0.29 0.36 AET 17 34 50 63% Resistance IT 48% 69% 85% 86% Wet / Dry AET 57% 76% 78% 79% The results of the test clearly indicate that the strength of one band increased with the length of the cellulose acetate fibers.

EXAMPLE 16 The purpose of this example is to illustrate that the pretreatment of superabsorbent polymer before adding it to an absorbent pad caused a superior pad resistance. The pulp used in this example is a non-softened and bleached version of NHB 405. The cellulose acetate used was 0.63 cm in length and 1.8 denier by 30.5 cm. A 15.2 cm control test pad was first formed comprising 60% by weight of untreated pulp and 40% by weight of PSA to which 2% by weight of triacetin had been added based on the weight of PSA. Then a second 15.2 cm test pad was produced by first adding 10% by weight (based on the weight of the pulp) of triacetin to the pulp. Then, the pulp was mixed with cellulose acetate in a weight ratio of 90/10. Untreated PSA was also added to bring the final weight ratio up to 40% PSA and 40% combined pulp and cellulose acetate. A final 15.2 cm test pad was prepared as described, with the exception that the PSA was first treated with 2% by weight of triacetin based on the weight of PSA. Then a dry pad tensile integrity test was carried out and the tensile index and tensile energy absorption were calculated. The results are indicated in the table below.

Resistance (Dry) IT AET Untreated pulp 0.04 4 treated with PSA Treated pulp (10% TA) 0.24 IB untreated with PSA Treated pulp 0.33 29 treated with PSA The PSA was still fluid after being treated with triacetin. In addition, it was observed that PSA retention was improved when previously treated with triacetin and formed into a pad according to the present invention. Finally, the resistance of the pad was similarly improved as shown by the above data.

EXAMPLE 17 The purpose of this example is to illustrate that triethyl citrate (CTE) is an excellent solvent to be used in accordance with the present invention. In addition, the retention time for triethyl citrate in a cellulose fiber matrix when stored openly is much greater than for triacetin in a fiber matrix. In addition, triethyl citrate causes a stronger bond between the binder medium and the cellulose fibers. 15.2 cm test pads were formed in a conventional manner. 10% solvent was first applied to the cellulose fibers based on the weight of the fibers. Then, the cellulose fibers were combined with cellulose acetate in a weight ratio of 90/10. A first group of test samples were then stored in plastic bags in an open room under normal relative humidity conditions. A second group of test samples were periodically selected from the bags and from the open room for dry pad tensile integrity tests. The results of these tests are indicated in the table below.

In the bag Open room Resistance (dry) (Nrn / g) Time of TA CTE TA CTE storage (hours) 0 0.63 0.87 25 0 .63 75 0. 65 0.91 0.61 0. 88 175 0.62 0. 90 0.51 0. 89 725 0.62 0.88 0 .34 0.89 These results clearly indicate that the dry tensile strength of the pad formed with triethyl citrate changed very little over time and was virtually independent of whether the pad was kept in a bag or in an open room. Conversely, the resistance diminished significantly when the pad was stored in the open room. The results indicate that triacetin dissipated into the atmosphere. The strength of the pad produced with triacetin when stored in a bag did not change over time.

EXAMPLE 18 The purpose of this example is to illustrate the effect of densification of a pad produced in accordance with the present invention when compared to a control pad. A control pad was produced using only NB 416 pulp. A second pad was produced in accordance with the present invention by first treating NB 416 pulp with 10% by weight of triacetin based on the weight of the pulp. The pad was then formed using a 90/10 by weight blend of the treated pulp and cellulose acetate. The plurality of test pads were then calendered at different densities. Then, traction integrity tests were performed on the pad and tensile energy absorption (TEA) was calculated. The pads that were caulked to a density of the order 4 g / cc exhibited a tensile energy absorption of 7 and 9 J / m2 for the control and agglutinated pads, respectively. A control pad with a density of the order of 0.19 g / cc exhibited an ETA of approximately 15 J / m2. Conversely, a bonded pad with a density of the order of 0.22 g / cc exhibited an AET of the order of 50 J / m2. Finally, a control pad having a density of the order of 0.275 g / cc exhibited an ETA of approximately 18 3 / m2, while a bonded pad with a density of the order of 0.29 g / cc exhibited an ETA of the order of 110 J / m2. These results indicate that the strength of a non-bonded pad will increase slightly with densification while the strength of a bonded pad will increase significantly with densification Micrographs To better illustrate the mechanism of the present invention, reference is made to the accompanying micrographs. In Figure 6, a cellulose fiber 100 adjacent to a cellulose acetate fiber 102 is shown before adding solvent to the web. Both fibers are relatively free to move. In Figure 7, after a solvent has been added to the system, the fiber surface of cellulose acetate 104 is partially solubilized and flows onto the surface of a cellulose fiber 106 in region 108. The cellulose acetate has wetted the cellulose fiber in region 108 and adheres firmly to it after the triacetin is absorbed. In Figure 8, two cellulose acetate fibers 110, 110 'are shown, after the triacetin has been added to the band. The surfaces of the fibers have been partially solubilized and have mutually flowed. Again, after the triacetin is absorbed, the cellulose acetate solidifies again and causes the fibers to adhere to each other. Referring to Figures 9 and 10, (which is an enlargement of a region of Figure 9), a cellulose fiber 112, a cellulose acetate fiber 114, and a large particle 116 of superabsorbent polymer are shown. The cellulose acetate fiber has been partially solubilized and has flowed on the surface of the PSA particle (superabsorbent polymer), adhering to it in this way. Another cellulose acetate fiber 118 has flowed onto the surface of the cellulose fiber 112 and adhered thereto. In this way, an interlaced web of fibers and particles was formed which results in a product having good integrity. Although preferred embodiments of the invention have been illustrated and described, it will be appreciated that various changes may be made therein without departing from the spirit and scope of the invention.

Claims

NOVELTY OF THE INVENTION CLAIMS

1. - An article comprising: a band of pulp cellulosic fibers, said fibers being intermingled with one another; a binder means for binding at least part of the cellulosic fibers with the binder means; and a solvent for said binder medium; the cellulosic fibers are insoluble in the solvent; when said binder media makes contact with the solvent, the medium is at least partially solubilized and becomes sticky so that the binder medium adheres to itself and to at least a portion of the cellulosic fibers; said solvent is present in an insufficient amount to completely solubilize the binder medium; said solvent, after partially solubilizing the surface of the binder medium, is sufficiently dissipated so that the binder means can solidify again, thereby binding itself and at least part of the cellulosic fibers.

2. The article according to claim 1, further characterized in that said binder means comprises second fibers intermixed throughout the band.

3. The article according to claim 2, further characterized in that the binder fibers are subetancially free of finish.

4. - The article according to claim 2, further characterized in that the solvent and at least part of the cellulosic fibers are combined first, and then the binder and the solvent and the cellulosic fibers combine to form a relatively hydrophilic bonded web.

5. The article according to claim 2, further characterized in that the cellulosic fibers and the binder fibers are first combined to form a mixing sheet, and where the solvent is then added.

6. The article according to claim 2, further characterized in that the solvent is added during or after the time in which the cellulosic fibers and the binder fibers are combined.

7.- The article in accordance with the claim 1, further characterized in that the binder means comprises particles intermixed throughout the band.

8.- The article in accordance with the claim 1, further characterized in that the binder means is applied as a coating on fibers that are insoluble in said solvent, the fibers coated with medium are intermixed throughout the band.

9.- The article in accordance with the claim 1, further characterized in that said binder means comprises cellulose acetate, cellulose butyrate, cellulose propionate, cellulose nitrate, vinyl chloride / vinyl acetate copolymer, acetylated pulp fibers, or mixtures thereof.

10.- The article in accordance with the claim 9, further characterized in that the solvent comprises triacetin, triethyl citrate, propanediol diacetate, propanediol dipropionate, propanediol dibutyrate, or mixtures thereof.

11.- The article in accordance with the claim 10, further characterized in that the binder means comprises fibers intermixed throughout the web.

12.- The article in accordance with the claim 11, further characterized in that it comprises a particulate additive intermixed over the entire web, the additive is present before the binder means is re-solidified so that it binds to the binder medium.

13.- The article in accordance with the claim 12, further characterized in that the additive comprises superabsorbent polymers, clay, titanium dioxide, sodium bicarbonate, zeolites, activated carbon, or mixtures thereof.

14.- The article in accordance with the claim 13, further characterized in that the superabsorbent polymers are pretreated by adding solvent thereto before combining the superabsorbent polymers in the band.

15. The article according to claim 11, further characterized in that the band has a density ranging from about 0.03 g / cc to about 1 g / cc.

16. - The article in accordance with the claim 6, further characterized in that the binder means is applied as a coating on fibers that are insoluble in the solvent; the fibers coated with medium are intermixed throughout the band.

17.- The article in accordance with the claim 16, further characterized in that it comprises a particulate additive intermixed throughout the web, the additive is present before the binder means is re-solidified and attached to the binder medium.

18.- The article in accordance with the claim 17, further characterized in that the additive comprises superabsorbent polymers, clay, titanium dioxide, sodium bicarbonate, zeolites, activated carbon, or mixtures thereof.

19.- The article in accordance with the claim 17, further characterized in that the superabsorbent polymers are pretreated by adding solvent thereto before combining the superabsorbent polymers in the band.

20. The article according to claim 17, further characterized in that the web has a density ranging from about 0.03 g / cc to about 1 g / cc.

21. The article according to claim 1, in a diaper.

22. The article according to claim 13, in a diaper.

23. The article according to claim 1, in an adult incontinence product.

24. The article according to claim 13, in an incontinence product for adults.

25. The article according to claim 1, in a female toilet product.

26. The article according to claim 13, in a female toilet product.

27. The article according to claim 1, further characterized in that the binder means is applied to the surface of the cellulosic fiber web.

28. A fibrous web comprising: cellulosic fibers of freely entangled pulp and second fibers, said cellulosic fiber and second fiber are evenly distributed throughout the web; a solvent; said cellulose fibers are insoluble in the solvent; said second fibers are at least partially soluble in the solvent; said solvent is present in an amount sufficient to partially solubilize the second fibers and cause the second fibers to bind to at least part of the cellulosic fibers, said solvent is present in an insufficient amount to completely solubilize the second fibers, said solvent being dissipates after partially solubilizing the second fibers so that the binder medium can solidify again.

29.- The band in accordance with the claim 28, further characterized in that said second fibers comprise cellulose acetate, cellulose butyrate, cellulose propionate, cellulose nitrate, vinyl chloride / vinyl acetate copolymer, acetylated pulp fibers, or mixtures thereof.

30.- The band in accordance with the claim 29, further characterized in that the solvent comprises triacetin, triethyl citrate, propanediol diacetate, propanediol dipropionate, propanediol dib? Tirato, or mixtures thereof.

31.- The band in accordance with the claim 30, further characterized in that the web has a density ranging from about 0.03 g / cc to about 1 g / cc.

32.- The band in accordance with the claim 31, further characterized in that it comprises particulate additives interspersed throughout the web, the additives are bonded to the second fibers.

33.- The band in accordance with the claim 32, further characterized in that the additives are superabsorbent polymers, clay, titanium dioxide, sodium bicarbonate, zeolites, activated carbon, or mixtures thereof.

34.- A method of manufacturing an article having improved integrity characteristics comprising: combining a binder medium with pulp cellulosic fibers to form a fiber matrix and medium that is mutually intermixed freely; after introducing a solvent for said binder medium into said mass of fibers and medium, said cellulosic fibers are insoluble in said solvent, when said binder medium is in contact with the solvent, the binder medium is at least partially solubilized and p > egajoso, so that the binding medium adheres to itself and at least part of the cellulosic fibers, said solvent is present in an insufficient amount to completely solubilize the binder means, the solvent after partially solubilizing the surface of the binder medium, it is disip > sufficiently so that the surface of the binder medium can solidify again, thereby permanently binding the medium to itself and to at least part of the cellulosic fibers.

35.- The method of compliance with the claim 34, further characterized in that said binder means comprises second fibers.

36.- The method of compliance with the claim 35, further characterized in that said solvent is added to at least part of said cellulosic fibers before the second fibers are combined with said part of cellulosic fibers.

37. The method according to claim 35, further characterized in that at least part of said solvent is added to the second fibers before the second fibers are combined with the cellulosic fibers.

38.- The method of compliance with the claim 35, further characterized in that said solvent is added during or after the time in which the cellulosic fibers and the second fibers are combined.

39.- The method according to claim 34, further characterized in that said binder means comprises cellulose acetate, cellulose thiomet, cellulose propionate, cellulose nitrate, vinyl chloride / vinyl acetate copolymer, pulp fibers acetylated, or mixtures thereof.

40. The method according to claim 34, further characterized in that the solvent comprises triacetin, triethyl citrate, propanediol diacetate, propanediol dipropionate, propanediol dibutyrate, or mixtures thereof.

41. A method of manufacturing an article having improved integrity characteristics comprising: combining a solvent for a binder medium with cellulosic pulp fibers to form a mass of solvent-containing fibers; introducing a binder medium into said fiber mass to form a fiber mass and binder means, said fibers are freely intermixed, said cellulosic fibers are insoluble in the solvent, when said binder means makes contact with the solvent is at least partially solubilized. medium and becomes sticky so that the binder medium adheres to itself and to at least part of the cellulosic fibers, said solvent is present in an insufficient amount to completely solubilize the binder medium, said solvent after partially solubilizing the surface of the cellulose. binder means, it dissipates sufficiently so that the surface of said binder means can solidify again, thereby permanently binding the medium to itself and to at least part of the cellulosic fibers.

42. The method according to claim 41, further characterized in that said binder means comprises second fibers.

43.- The method of compliance with the claim 41, further characterized in that said binder means comprises cellulose acetate, cellulose butyrate, cellulose propionate, cellulose nitrate, vinyl chloride / vinyl acetate copolymer, acetylated pulp fibers, or mixtures thereof.

44. The method according to claim 36, further characterized in that the solvent comprises triacetin, triethyl citrate, propanediol diacetate, propanediol dipropionate, propanediol dibutyrate, or mixtures thereof.

45. A method for manufacturing an article having improved integrity characteristics comprising: introducing a sheet containing pulp cellulosic fibers into a defibrator; introduce a sheet containing binder fibers in the deefibrator; introducing a solvent for the binder fibers in the defibrator, the cellulosic fibers are insoluble in the solvent; defibrating the fibers to form a fluff of cellulosic fibers and uniformly dispersed binder fibers and to distribute the solvent uniformly throughout the lint; forming a loose band of said fluff, when said binder fibers make contact with the solvent, the surface of the binder fibers is at least partially solubilized and becomes sticky so that said binder fibers adhere to themselves and at least ap > art of said cellulosic fibers, said solvent is present in an insufficient amount to completely solubilize the binding fibers, said solvent after partially solubilizing the surface of the binding fibers is sufficiently dissipated so that the surface of said binding fibers can solidify again, uniting with it permanently the fibers binding to themselves and to at least part of the cellulosic fibers.

46.- The method of compliance with the claim 45, further characterized in that the solvent is combined with the binder fibers before the sheet thereof is introduced into the defibrator.

47.- The method of compliance with the claim 46, further characterized in that said binder means comprises cellulose acetate, cellulose butyrate, cellulose propionate, cellulose nitrate, vinyl chloride / vinyl acetate copolymer, acetylated pulp fibers, or mixtures thereof.

48.- The method of compliance with the claim 46, further characterized in that the solvent comprises triacetin, triethyl citrate, propanediol diacetate, propanediol dipropionate, propanediol dibutyrate, or mixtures thereof.

49. The method according to claim 45, further characterized in that the solvent is combined with at least part of the cellulosic fibers before the sheet thereof is introduced into the defibrator.

50.- The method according to claim 49, further characterized in that said binder means comprises cellulose acetate, cellulose butyrate, cellulose nitrate, cellulose propionate, vinyl chloride / vinyl acetate copolymer, acetylated pulp fibers, or mixtures thereof.

51.- The method of compliance with the claim 49, further characterized in that the solvent comprises triacetin, triethyl citrate, propanediol diacetate, propanediol dipropionate, propanediol dibutyrate, or mixtures thereof.

52.- The method of compliance with the claim 45, further characterized in that said binder means comprises cellulose acetate, cellulose butyrate, cellulose nitrate, cellulose propionate, vinyl chloride / vinyl acetate copolymer, polyvinyl acetate, acetylated pulp fibers, or mixtures thereof.

53.- The method of compliance with the claim 45, further characterized in that the solvent is triacetin, triethyl citrate, propanediol diacetate, propanediol dipropionate, propanediol dibutyrate, or mixtures thereof.

54. The method according to claim 45, further characterized in that the solvent is added at the time of or after which both the cellulose fibers and the binder fibers are introduced into the deener.

The method according to claim 45, further characterized in that said binder means comprises cellulose acetate, cellulose butyrate, cellulose nitrate, cellulose propionate, vinyl chloride / vinyl acetate copolymer, acetylated pulp fibers, or mixtures thereof.

56.- The method of compliance with the claim 55, further characterized in that the solvent comprises triacetin, triethyl citrate, propanediol diacetate, propanediol dipropionate, propanediol dibutyrate, or mixtures thereof.

57.- Pulp cellulosic fibers containing a solvent for a binder medium, said fibers are insoluble in the solvent, said fibers are able to be combined with the binder medium to form a band of freely intermingled cellulosic fibers, when said binder medium is in contact with the cellulose fibers. contact with the solvent is able to solubilize p > or at least partially and to become p > Due to the fact that said binding agent adheres to itself and to at least part of the cellulosic fibers, said solvent is present in an amount insufficient to completely solubilize the binder medium, said solvent after partially solubilizing the surface of the binder medium. it dissipates sufficiently so that the binder means can solidify again, thereby joining the medium to itself and to at least part of the cellulosic fibers.

58. The fibers according to claim 57, characterized in that the solvent comprises triacetin, triethyl citrate, propanediol diacetate, propanediol dipropionate, propanediol dib? Tirato, or mixtures thereof.

59.- Pulp cellulosic fibers mixed with a binder medium to form a band of freely intermixed cellulose fibers and binder medium, said binder means is soluble in a predetermined solvent, said cellulose fibers are insoluble in said solvent, when said binder means makes contact with the solvent is able to be at least partially solubilized and to become sticky, so that said binder means is it adheres to itself and to at least part of said cellulosic fibers, said solvent is present in an insufficient amount to completely solubilize the binder medium, said solvent after partially solubilizing the surface of the binder medium is sufficiently dissipated so that said binder means can solidify again, thereby joining the medium to itself and at least part of the cellulosic fibers.

60.- Fibers in accordance with the claim 59, further characterized in that the binder means comprises second fibers intermixed by all the cellulosic fibers.

61.- Fibers in accordance with the claim 60, further characterized in that the cellulosic fibers comprise cellulose acetate, cellulose butyrate, cellulose nitrate, cellulose propionate, vinyl chloride / vinyl acetate copolymer, acetylated pulp fibers, or mixtures thereof, and the solvent comprises triacetin, triethyl citrate, propanediol diacetate, propanediol dipropionate, propanediol dibutyrate, or mixtures thereof.

62.- An article that includes: a dorsal leaf; an underlying storage layer comprising a band of pulp cellulosic fibers, said web includes a binder means for binding at least part of said cellulosic fibers with the binder means and a solvent for said binder means, said cellulosic fibers being insoluble in said binder. solvent, when said binder medium makes contact with the solvent, it is at least partially solubilized and becomes sticky, so that said binder medium adheres to itself and to at least part of the cellulosic fibers, said solvent is present in a insufficient amount to completely solubilize the binder means, said solvent after partially solubilizing the surface of the binder medium is sufficiently dissipated so that the binder medium can solidify again, thereby binding the medium to itself and to at least part of the cellulosic fibers; and a front sheet on top of said band.

63.- The article in accordance with the claim 62, further characterized in that said binder means comprises second fibers interspersed throughout the band.

64.- The article in accordance with the claim 63, further characterized in that it comprises an acquisition layer comprising a second band of cellulosic fibers located between said front sheet and said band.

65.- The article in accordance with the claim 64, further characterized in that said acquisition layer comprises a binder means for joining at least part of said cellulosic fibers to the binder means; and a solvent for said binder means, said cellulosic fibers are insoluble in said solvent, when said binder medium makes contact with the solvent, it is at least partially solubilized and becomes sticky, so that said binder medium adheres to itself and to at least part of the cellulosic fibers, said solvent is present in an insufficient quantity to completely solubilize the binder medium, said solvent, after partially solubilizing the surface of the binder medium, dissipates sufficiently so that said binder medium can solidify again, thereby joining the medium to itself and at least part of the cellulosic fibers.

66.- The article according to claim 65, further characterized in that the binder means comprises second fibers intermixed throughout the acquisition layer.

67.- The article in accordance with the claim 64, further characterized in that the second fibers comprise cellulose acetate, cellulose butyrate, cellulose propionate, cellulose nitrate, vinyl chloride / vinyl acetate copolymer, acetylated pulp fibers, or mixtures thereof, and the solvent comprises triacetin, triethyl citrate, propanediol diacetate, propanediol dipropionate, propanediol dibutyrate, or mixtures thereof.

68.- The article according to claim 66, further characterized in that the second fibers comprise cellulose acetate, cellulose butyrate, cellulose propionate, cellulose nitrate, vinyl chloride / vinyl acetate copolymer, acetylated pulp fibers, or mixtures thereof, and the solvent comprises triacetin, triethyl citrate, propanediol diacetate, propanediol dipropionate, propanediol dibutyrate, or mixtures thereof.

69.- An absorbent article that includes: a dorsal layer impermeable to liquid; and a storage layer on top of said dorsal layer, said storage layer comprises a liquid permeable fabric on top of a band of pulp cellulosic fibers, said fabric being on the opposite side of said dorsal layer band, said cellulosic fibers being intermixed freely with one another, a binder means for joining at least part of said cellulosic fibers to the binder medium, and a solvent for the binder medium, said cellulosic fibers are insoluble in the solvent, when said binder medium makes contact with the solvent, it solubilizes at least partially and becomes sticky, so that said binder medium adheres to itself and to at least part of said cellulosic fibers, said solvent is present in an insufficient quantity to completely solubilize the binder medium, said solvent, after of partially solubilizing the surface of the binder medium, it dissipates sufficiently so that The binder means may solidify again, thereby joining the medium to itself and to at least part of the cellulosic fibers.

70. The article according to claim 69, further characterized in that said binder means comprises second fibers interspersed throughout the band.

71.- The article according to claim 70, further characterized in that the second fibers comprise cellulose acetate, cellulose butyrate, cellulose propionate, cellulose nitrate, vinyl chloride / vinyl acetate copolymer, acetylated pulp fibers, or mixtures thereof, and the solvent comprises triacetin, triethyl citrate, propanediol diacetate, propanediol dipropionate, propanediol dibutyrate, or mixtures thereof.

72.- An absorbent article that includes: a dorsal leaf; a storage layer comprising a band of fibers on top of said dorsal layer; an upper layer comprising a band of fibers on top of said storage layer; an intermediate layer interposed between said storage layer and said distribution layer comprising a band of pulp cellulosic fibers, said cellulosic fibers being freely intermixed with each other, a binder means for joining at least part of the cellulosic fibers to the binder medium , and a solvent for said binder means, said cellulosic fibers are insoluble in the solvent, when said binder medium makes contact with the solvent, it is at least partially solubilized and becomes sticky, so that the binder media adhere to itself and at least part of the cellulosic fibers, said solvent is present in an insufficient quantity to completely solubilize the binder medium, said solvent, after partially solubilizing the surface of the binder medium, dissipates sufficiently so that said binder medium can solidify again , uniting with it the means to itself already by at least part of the cellulosic fibers; and a front layer on top of said top layer.

73. The article according to claim 72, further characterized in that said binder means comprises second fibers interspersed throughout the band. 74.- The article according to claim 73, further characterized in that the second fibers comprise cellulose acetate, cellulose butyrate, cellulose propionate, cellulose nitrate, vinyl chloride / vinyl acetate copolymer, acetylated pulp fibers, or mixtures thereof and wherein the solvent comprises triacetin, triethyl citrate, propanediol diacetate, propanediol dipropionate, propanediol dibutyrate, or mixtures thereof. 75.- The article according to claim 2, further characterized in that the binder fibers are subetanially straight.