MXPA99010408A - Soft multi-ply tissue paper having a surface deposited strengthening agent - Google Patents

Abstract

Strong and soft multi-ply tissue paper products useful as absorbent sanitary products such as bath tissue, facial tissue, and absorbent towels are disclosed. At least one internal surface of the tissue paper product has a surface deposited strengthening agent.

Description

SOFT TISSUE PAPER OF MULTIPLE SHEETS THAT HAS A REINFORCEMENT AGENT DEPOSITED ON THE SURFACE FIELD OF THE INVENTION This invention relates, in general, to tissue paper products, more specifically, it refers to tissue paper products that contain surface-applied reinforcing agents.

BACKGROUND OF THE INVENTION Tissue paper, sanitary ware products are widely used. These items are offered commercially in formats made for a variety of uses such as facial tissues, toilet paper and absorbent towels. All these sanitary products share a need to be both hard and soft. Softness is a tactile, complex imsion produced by a product when it is rubbed against the skin. The purpose of being soft is that these products can be used to clean the skin without being irritating. One of the most important physical properties related to softness is generally considered by those skilled in the art to be the strength of the product. The resistance is the capacity of the product, and its constituent frames, to maintain physical integrity and resist tearing, breaking and defibering under the conditions of use. The achievement of both a high smoothness and a high level of strength has been an object of those dealing with the field of the ent invention. One field that has been exploited in this regard has been to select and modify the morphologies of the cellulose fiber and the design of paper structures to take the optimal advantages of the various available morphologies. The technique applicable in this field includes Vinson et al., In the Patent of the United States No. 5,228,954, issued July 20, 1993, Vinson in United States Patent No. 5,405,499, issued April 11, 1995, and Cochrane et al. in the Patent of the United States No. 4,874,465 issued October 17, 1989, all describe methods for selecting or improving fibrous sources for making tissue paper and towels of superior properties. The applicable technique is further illustrated by Carstens in U.S. Patent No. 4,300,981, issued November 17, 1981, which describes how fibers can be incorporated to be in accordance with paper structures, so that they have maximum potential. of softness. While these techniques are widely recognized, as illustrated by these examples of the prior art, they may offer only some limited potential to make the cleaning implements, comfortable, truly effective, in tissue papers. Another area that has received a considerable amount of attention is the addition of chemical softening agents (also referred to herein as "chemical softeners") to towel and tissue products. As used herein, the term "chemical softener" refers to any chemical ingredient that improves the tactile sensation perceived by the consumer who holds a particular paper product and rubs it through the skin. Although desirable for paper products, softness is a particularly important property for tissue, facial and sanitary products. This perceptible, tactile softness can be characterized in an enunciative way by friction, flexibility, and softness, as well as subjective descriptors, such as a velvet, silk or flannel type sensation. Chemical softeners, for example purposes only, include basic silks such as paraffin P917 and wax and oils such as mineral oil and silicone oil as well as petrolatum and more complex lubricants and emollients such as quaternary ammonium compounds with long alkyl chains, functional silicones, fatty acids, fatty alcohols and fatty esters. The field of work in the prior art corresponding to chemical softeners has taken two routes. The first route is characterized by the addition of softeners to a tissue paper web during its formation either by adding an attractive ingredient to the pulp tubs that will eventually form in a tissue paper web, to the slurry of pulp as it approaches a papermaking machine, or to the wet weft when it resides in a fourdrinier fabric or dryer cloth in a paper dryer machine. The second route is classified by the addition of chemical softeners to a weave of tissue paper after the weave is dried. Applicable processes can be incorporated into the papermaking operation for example, by spraying on the dry weft before it is wound onto a roll of paper. The technique and emplificativa related to the previous classified route, when adding softeners P917 Chemicals to tissue paper prior to assembly into a frame includes U.S. Patent No. 5,264,082, issued to Phan and Trokhan on November 23, 1993, incorporated herein by reference. These methods have found wide use in the industry, especially when it is desired to reduce the strength that would otherwise be present in the paper and when the papermaking process, particularly the creping operation, is strong enough to tolerate incorporation. of the binding inhibition agents. However, there are problems associated with these methods, well known to those skilled in the art. First, the location of the chemical softener is not controlled; it is spread so widely through the paper structure as the fiber to which it is applied is supplied. In addition, there is a loss of paper strength that accompanies the use of these additives. While not bound by theory, it is widely believed that additives tend to inhibit the formation of hydrogen bonds from fiber to fiber. There may also be a loss of control of the sheet as it is creped from the Yankee dryer. Again, a widely trusted theory is that the additives interfere with the coating in the Yankee dryer P917 so that the connection between the wet screen and the dryer is weakened. The prior art such as U.S. Patent No. 5,487,813, issued to Vinson, et al., On January 30, 1996, incorporated herein by reference, describes a chemical combination to mitigate the effects mentioned above on the resistance and adhesion to the creping cylinder; however, there still remains a need to incorporate a chemical softener as long as it minimizes the effect on the weft strength and interference with the production process. The additional exemplary technique related to the addition of chemical softeners to the tissue paper web during its formation includes U.S. Patent No. 5,059,282, issued to Ampulski, et al., October 22, 1991 incorporated herein by reference. The Ampulski patent describes a process for adding a polysiloxane compound to a wet tissue paper web (preferably at a fiber consistency between about 20% and about 35%). This method represents an advance in several aspects on the addition of chemicals in the pulp tubs that supply the papermaking machine. For example, this means points the application to one of the surfaces of the weft as the opposite of distributing the additive over all the fibers of the raw materials. However, these methods fail to overcome the main disadvantages of adding chemical softeners to the wet end of the papermaking machine, namely, the resistance effects and the effects on the Yankee dryer coating that a dryer must employ. Due to the aforementioned effects on the strength and interruption of the papermaking process, a considerable technique has been devised to apply chemical softeners to already dry paper webs at either the dry end of the machine for the manufacture of paper. paper or in a conversion manufacturing, separated subsequent to the papermaking step. The example technique of this field includes U.S. Patent No. 5,215,626, issued to Ampulski, et al. on June 1, 1993, United States Patent No. "5,246,545, issued to Ampulski et al., on September 21, 1993, and the United States Patent.

No. 5,525,345, issued to Warner, et al. on June 11, 1996, all incorporated herein by reference. Patent 5,215,626 describes a method for preparing soft tissue paper by applying a polysiloxane to a dry weft. Patent 5,246,545 describes a similar method that uses a transfer surface, heated. Finally, the Warner patent describes application methods that include roller coating and extrusion to apply particular compositions to the surface of a dry tissue paper web. While each of these references represents advances over the so-called wet-end methods, prior, particularly with respect to eliminating the degrading effects on the papermaking process, none has been able to fully cope with the loss of resistance to the tension that accompanies the application to the dry paper web. Achieving high potential softeners without degrading resistance has been an object of those dealing with the field of the present invention. In practice, the chemical softening techniques mentioned above have typically been the practice of designing the structure at excessively high levels of strength in order to compensate for the unavoidable resistance losses that will occur in the use of chemical softeners. Those skilled in the art will recognize that the use of pulp refiners or the addition of resins in the papermaking process can be easily employed for this purpose; however, they inevitably result in a loss of softness. Therefore, the underlying improvement in smoothness is limited when observed at a constant tensile strength. It has been recognized for a long time that binders can be applied on the surface to tissue paper webs to impart improved properties including new relationships between strength and softness. U.S. Patent No. 3,862,877 issued to Camden on January 28, 1975 and incorporated herein by reference is exemplary. In this reference, a laminated tissue paper product comprising at least three layers is described. While this reference describes the use of latex binders, high viscosity, with high solids content, to impregnate a central layer of tissue paper and the additional union of the central layer with each of the two outer layers without migration in any of the two outer layers; the conditions of the invention produce a laminated product in which the outer layers of tissue paper are bound to the central layer in a total manner by inducing a multilayer tissue paper weft product instead of a multi-sheet tissue paper product . The multi-sheet tissue paper products are somewhat softer than similar multilayer tissue paper products. It has also been recognized in practice the use of binders applied to the inner surfaces of the multifilament tissue paper webs in order to form discrete joints between the sheets of the multi-sheet tissue paper products, effectively preventing separation. of the leaves in use, for example, but maintaining the structural identity as a product of multiple leaves. The example technique in this area is U.S. Patent No. 5,143,776, issued to Givens and incorporated herein by reference. This technique does not teach the use of the binder of sheets to significantly reinforce the product of multiple sheets, except with respect to the tendency of the sheets to be separated, that is, the resistance to dry tension of the product does not increase in a meaningful Accordingly, it is an object of the present invention to provide a soft, multi-sheet tissue paper product that achieves a high level of strength.

This and other objects are obtained using the present invention as taught in the following description.

SUMMARY OF THE INVENTION The invention is a tissue paper product, resistant and soft, with multiple sheets, wherein at least one inner surface of the tissue paper has a reinforcing agent deposited on the surface. The composition of the reinforcing agent is preferably selected from a wide variety of polymeric materials including solvent based adhesives, water soluble polymers, water dispersible additives, emulsion polymers, and hot melt adhesives. Suitable polymeric binders include starch, polyvinyl alcohol, polyamide resins, polyacrylamide resins, acrylic polymers, styrene-butadiene copolymers, vinyl acetate polymers, ethylene-vinyl acetate copolymers, vinyl chloride polymers, chloride polymers of vinylidene, vinyl chloride-vinylidene copolymers, acryl-ethyl copolymers, and ethylene-acrylic copolymers. The elastomeric latex emulsions are P917 preferred fluidized forms of the reinforcing agent. The reinforcing agents are preferably somewhat tacky, having vitreous transition temperatures of about 0 degrees C or less, for example, although glass transition temperatures of about 50 degrees to about -50 degrees C may be employed in the present invention. . The most preferable reinforcing agent is an acrylic latex with a vitreous transition temperature between about -30 degrees C and about 10 degrees C. The reinforcing agent is preferably a minor component of the tissue paper product, which preferably comprises only from about 0.5% to about 10% of the tissue paper product by weight based on the dry weight of the reinforcing agent compared to the dry weight of the tissue paper product. An even more preferable range of the composition is for the reinforcing agent comprising from about 2% to about 5% of the tissue paper product by weight. The preferred embodiment of the present invention is a two-ply tissue paper product wherein both inner surfaces of the product P917 contain the surface reinforcing agent. Preferably, the reinforcing agent is distributed over essentially the inner, complete surface of the tissue paper web in which it resides. More preferably, a discrete, scattered pattern of relatively concentrated areas of the dispersed reinforcing agent is provided within a field of a relatively diffuse concentration. The function of the concentrated, scattered areas is to provide a sufficient concentration of the reinforcing agent to effect an intermittent leaf joint with the adjacent tissue paper web. The function of the diffuse concentration of the reinforcing agent is to provide this reinforcement of the tissue paper product without effecting a bonding of sheets in these areas. The invention is additionally a process for producing a soft, durable, multi-sheet tissue paper product. The steps in the process are: a) applying by surface deposition a reinforcing agent, fluidized on the surface of a tissue paper web forming a weave of tissue paper, reinforced on the surface comprising from about P917 0.5% up to about 10% of the reinforcing agent; and b) combining the reinforced tissue paper web on the surface of step (a) with at least one additional tissue paper web to form a multi-sheet tissue paper product, orienting the tissue paper web, reinforcing the surface of such tissue paper. The surface comprising the reinforcing agent forms an inner surface of the multi-leaf tissue paper product.

The combination step of the process of the present invention can cause a bond to be formed between two or more of the tissue paper webs; however, if these joints are caused to form, they should not be formed on a majority of the surfaces of the frames in order to maintain an access plane between the tissue paper webs comprising the multi-sheet tissue paper prod the present invention. The fluidized reinforcing agent is deposited in a preferably non-uniform manner such that a discrete, scattered, uniform pattern of relatively concentrated areas of the fluidized reinforcing agent is deposited within a P917, a relatively diffuse, uniformly applied reinforcing agent fluidized pattern. In this case, it is preferred to carry out the combination step (b) such as to apply a sufficient combination pressure to substantially bond the weft of tissue paper reinforced on the surface to the weft of additional tissue paper by the bonding via the areas Concentrates of the reinforcing agent while using an insufficient combination pressure to effect bonding by the areas of the reinforcing agent residing in the relatively diffuse, uniform field. The preferred process for depositing the reinforcing agent is stamping. The fluidized reinforcing agent is preferably a latex emulsion. Acrylic latex is particularly suitable. More preferably, the latex emulsion has a solids content between about 10% and about 50% and more preferably between about 20% and about 30%. The durable, soft, multi-sheet tissue paper product of the present invention preferably has a basis weight between about 20 g / m2 and about 70 g / m2 and more preferably between about 25 g / m2 and P917 approximately 50 g / m2. It has a density between about 0.3 g / cm3 and about 0.6 g / cm3 and more preferably between about 0.1 g / cm3 and 0.2 g / cm3. The soft tissue paper of the present invention additionally comprises papermaking fibers of both hardwood and softwood types wherein at least about 50% of the papermaking fibers are preferably of the hardwood type and at least about 10% are preferably of the softwood type. The hardwood and softwood fibers can be homogeneously distributed, but can be advantageously isolated by delegating each to separate layers wherein one or more of the tissue paper webs comprising the multiple tissue paper product. The sheets additionally comprise an inner layer and at least one outer layer. The stratified arrangement, preferred in this case, is to relegate the soft wood type fibers to a layer that matches an interior surface and the hard wood type fibers to the layer that matches the exterior surface. The tissue paper webs of the present invention are preferentially creped, that is, they are produced in a papermaking machine ending with a Yankee dryer to which a partially dry papermaking weft adheres, and in which It dries and from which it is removed by the action of a creping blade, flexible. While the characteristics of creped paper webs, particularly when the creping process is preceded by pattern densification methods, are preferred to practice the present invention, the non-creped tissue paper is also not a satisfactory substitute and practice of the present invention using non-creped tissue paper is specifically incorporated within the scope of the present invention. Uncreated tissue paper, a term as used herein, refers to tissue paper that is dried in a noncompressive manner, more preferably by pass drying. The resulting dried-out patches are densified in the pattern such that relatively high density areas are dispersed within a high volume field, which includes patterned densified fabric in which the relatively high density areas are continuous and discrete. the high volume field. To produce tissue webs, without creping, an embryonic mesh is transferred from the carrier of foraminous formation in which it is P917 placed, to a transfer tissue carrier, of high fiber content support, which moves slower. The weft is then transferred to a drying fabric in which it is dried to a final dryness. These webs may offer some advantages in surface smoothness compared to creped paper webs. Techniques for producing tissue paper not creped in this manner are taught in the prior art. For example, Wendt, et al. in European Patent Application 0 677 612A2, published October 18, 1995 and incorporated herein by reference, teaches a method for making soft tissue products without creping. In another case, Hyland et al. in European Patent Application 0 617 164 To the published September 28, 1994 and incorporated herein by reference, teaches a method for making dry, smooth, creped leaves. The tissue paper webs are generally comprised essentially of papermaking fibers. Small amounts of functional, chemical agents such as wet strength or dry strength binders, retention aids, surfactants, hardeners, chemical softeners, creping facilitating compositions, and fillers are included on a frequent basis, but these are they typically only use in smaller quantities. The papermaking fibers most frequently used in tissue papers are virgin chemical wood pulps.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is an elevation, side view of a photo etched combination and stamping arrangement illustrating the method for forming the multi-sheet tissue paper product comprising the reinforcing agent deposited on the surface of the present invention. The process depicted in Figure 1 applies the reinforcing agent to a surface of the tissue paper web by an indirect gravure printing method. Figure 2 is an elevation, side view of a photo etched combination and stamping arrangement illustrating the method for forming the multi-sheet tissue paper product comprising the reinforcing agent deposited on the surface of the present invention. The process depicted in Figure 2 applies the reinforcing agent to a surface of the tissue paper web by a direct gravure printing method.

P917 Figure 3 is a side elevation view of a photo etched combination and stamping arrangement illustrating the method for forming the multi-sheet tissue paper product comprising the reinforcing agent deposited on the surface of the present invention. The process depicted in Figure 3 applies the reinforcing agent to a surface of the two tissue paper webs by a direct gravure printing method, which are then combined to form a multi-sheet tissue paper product. Figure 4 is a schematic representation, in cross-section, of the multi-sheet tissue paper product of the present invention illustrating the areas in which the reinforcing agent is present. Figure 5 is a schematic representation illustrating the detail of the recessed areas for use in the stamping rollers illustrated in Figures 1, 2 and 3, i.e. the gravure roll 4 of Figure 1, the gravure roll 26 of Figure 2, the gravure roll 64 of Figure 3. Figure 6 is a scan electron micrograph of the felt side of a tissue paper web comprising long fibers, short fibers, and the P917 reinforcing agent applied on the surface. Figure 7 is a scanning electron micrograph of the cross section of a tissue paper web comprising long fibers, short fibers and the reinforcing agent applied on the surface.

DETAILED DESCRIPTION OF THE INVENTION While this specification concludes with the claims that point out in a particular way and claim differently the subject considered as the invention, it is believed that the invention can be better understood from a reading of the following detailed description and the attached examples. As used herein, the term "comprising" means that the various components, ingredients, or steps, may be used together in the practice of the present invention. Accordingly, the term "comprising" embraces the more restrictive terms "consisting essentially of" and "consisting of". As used herein, the term "water soluble" refers to materials that are soluble in water at least 3%, by weight, at 25 SC. As used herein, the terms "tissue paper web, paper web and paper web P917"all refer to paper sheets made by a process comprising the steps of forming an aqueous papermaking raw material, depositing this raw material on a foraminous surface, such as a Fourdrinier mesh, and removing the water from the paper. raw material such as by gravity or vacuum-assisted drainage, form an embryonic web, transfer the embryonic web to a felt or fabric in which it is partially or completely dried before being optionally transferred to one or more drum driers, cylindrical before it rolls up on a reel, the terms "multi-sheet tissue paper web, multilayer paper web, multi-ply web, multi-ply tissue "are all used interchangeably in the art to refer to paper webs prepared from two or more layers of the papermaking raw material, aqueous, which are preferably comprised of different types of fiber, fibers which are typically relatively long softwood fibers and relatively short hardwood fibers, as used in the manufacture of tissue paper.The layers are preferentially from the deposit of separate streams of diluted pulps of fiber in one or more P917 endless foraminous surfaces. If the individual layers are formed initially on separate, foraminous surfaces, the layers can subsequently be combined to form a multilayer tissue paper web. The characteristic definition of the multilayer tissue paper web is that the separated layers are bonded together on essentially their entire surface. As used herein, the term "single sheet tissue paper product" means that it is comprised of a sheet of tissue paper; the sheet may be substantially homogeneous in nature or may be a multilayer tissue paper web. As used herein, the term "multi-sheet tissue paper product" means that it is comprised of more than one sheet of tissue paper. The sheets of a multi-sheet tissue paper product may be substantially homogeneous in nature or may be plies of multilayer tissue paper. The characteristic definition of the multifilament tissue paper product is that the sheets remain predominantly free from attachment to adjacent sheets, that is, if the sheets of the multi-sheet tissue paper product are joined, they can be joined only in a minority, of its surface.

P917 The present invention is a tissue paper product, strong and soft, multi-leaf, wherein at least one inner surface of the tissue paper has a reinforcing agent deposited on the surface. As used herein, the term "Interior surface" refers to any surface of the multi-sheet tissue paper product that remains essentially unexposed when the product is used. The interior surfaces may be partially visible from the exterior of the product, for example, by the limited opacity of the tissue paper webs, constituents, but, the characteristic definition of an interior surface is that it is substantially protected during use by the presence of the papermaking fibers constituting the tissue paper webs comprising the product. As used herein, the term "outer surface" refers to predominantly exposed surfaces of the tissue paper webs comprising the multi-sheet tissue paper products. The composition of the reinforcing agent is preferably selected from a wide variety of polymeric materials including P917 solvent based adhesives, water soluble polymers, water dispersed adhesives, emulsion volumes, and hot melt adhesives. The reinforcing agents may be capable of impacting the wet strength in addition to the dry strength. Suitable polymeric binders include starch, polyvinyl alcohol, polyamide resins, polyacrylamide resins, acrylic polymers, styrene-butadiene copolymers, vinyl acetate polymers, ethylene-vinyl acetate copolymers, vinyl chloride polymers, polymers of vinylidene chloride, vinyl chloride-vinylidene copolymers, acrylonitrile copolymers, and ethylene-acrylic copolymers. During application, the strengthening agent must be rendered fluid so that it can be deposited on the surface of the tissue paper web. The terms "fluidized reinforcing agent" or "fluidized form of the reinforcing agent" are used herein to distinguish between the reinforcing agent in its application form as compared to its shape after application on the surface of the wefts of tissue paper of the present invention. Those skilled in the art will recognize that a wide variety of P917 means to achieve fluidization. If the polymer is soluble or dispersible in water or solvent, it can be dissolved or dispersed in water or compatible solvent. If the polymer is thermoplastic, it can be subjected to sufficiently increase in temperature to soften or melt the polymer to render it fluid. If it is a finely divided solid, it can be dispersed in a current of air. The most preferred form of the fluidized strengthening agent is an aqueous emulsion. Water is a cheap, safe vehicle, and emulsions are characterized by having an activity with a relatively high solids content without having a high viscosity. Synthetic, elastomeric latex emulsions are particularly preferable, fluidized forms of the reinforcing agent. The reinforcing agents are preferably somewhat tacky, having vitreous transition temperatures of 0 degrees C or less, for example, but vitreous transition temperatures from 50 degrees to -50 degrees C may be employed in the present invention. The reinforcing agent more preferred is an acrylic latex with a glass transition temperature between about -30 degrees C and P917 about 10 degrees C. The reinforcing agent is employed in an effective amount, that is, to produce the desired level of strength increase desired. If the additional amount is too small, an increase in resistance will not be observed. If the added amount is too large, the application will damage the performance of the tissue paper product with respect to properties such as thickness and absorbency. Preferably, the strength agent will be a minor component of the tissue paper product, which preferably comprises only about 0.5% to about 10% of the tissue paper product by weight based on the dry weight of the reinforcing agent compared to dry weight of the tissue paper product. An even more preferable range of the composition is that the reinforcing agent comprises from about 2% to about 5% of the tissue paper product by weight. The preferred number of sheets comprising the multi-sheet tissue paper product of the present invention is two, although three or more sheets may also be used. The two-leaf products have two internal surfaces. One or, more preferably, both, of the inner surfaces may P917 possessing the reinforcing agent deposited on the surface of the present invention. Preferably, the reinforcing agent is distributed essentially on the inner, complete surface of the tissue web in which it resides. More preferably, a discrete, scattered pattern of relatively concentrated areas of the dispersed reinforcing agent is provided within a field of a relatively diffuse concentration. The function of the concentrated, scattered areas is to provide a sufficient concentration of the reinforcing agent to effect an intermittent union of sheets with the adjacent tissue paper web. The function of the diffuse concentration of the reinforcing agent is to provide reinforcement of the tissue paper product without effecting a bonding of sheets in these areas. Tissue paper webs are characterized by frequently having widely uneven properties from one surface to the other. This arises from the nature of the processes from which they originate. For example, if the tissue paper web is made in a papermaking machine that uses a Yankee dryer, the differences are believed to be P917 is primarily an artifact for making one of the surfaces secured to the relatively smooth surface of the Yankee, while the other surface, here called the "felt-side" surface, is pressed or deflected into a felt or fabric . In an analogous manner, a non-creped fabric, insofar as it is not secured to a Yankee dryer, by nature of having one of its surfaces deviate when it is transferred from its foraminous forming carrier in which a carrier is placed. Highly fiber-bearing support transfer fabric, which moves slower, will have a relatively textured surface, also referred to herein as a "felt-side" surface. In any case, the surface opposite the surface of the felt side is referred to herein as the "mesh side" surface. There is a preferred orientation of the tissue paper webs comprising the multi-ply tissue paper product of the present invention. The preferred orientation of the frames is such that the outer surfaces coincide with the surfaces of the mesh side while the inner surfaces coincide with the surfaces of the felt side. Without being bound by theory, P917 the inventors believe that the greater smoothness of the mesh-side surfaces is advantageously used as an outer surface while the greater surface texture of the felt side offers improved ease of depositing the reinforcing agent as taught at the moment. The invention is additionally a process for producing a tissue paper product, multi-sheet, resistant, soft. The steps in the process are: a) applying by surface deposit a fluidized reinforcing agent on the surface of a tissue paper web that forms a weave of tissue paper reinforced on the surface comprising from about 0.5% to about 10 % of the reinforcement agent; and b) combining the reinforced tissue paper web on the surface of step (a) with at least one additional tissue paper web to form a multi-sheet tissue paper product, orienting the weft of reinforced tissue paper on the surface of the tissue. such that the surface comprising the reinforcing agent forms an inner surface of the multi-sheet tissue paper product. The fluidized reinforcing agent is deposited in a preferably non-uniform manner of P917 such that a discrete, scattered, uniform pattern of relatively concentrated areas of the fluidized strengthening agent is deposited within a relatively diffuse, uniformly applied, fluidized reinforcing agent pattern. In this case, it is preferred to carry out the combination step (b) such as to apply a sufficient combination pressure to substantially join the reinforced tissue paper web to a surface to the additional tissue paper web by bonding the areas Concentrates of the reinforcing agent as long as an insufficient combination pressure is employed to effect bonding by the areas of the reinforcing agent residing in the relatively diffuse, uniform field. The preferred process for depositing the reinforcing agent is stamping. The most preferred stamping method is direct stamping. The fluidized reinforcing agent is preferably a latex, aqueous emulsion. Acrylic latex is particularly suitable. More preferably, the latex emulsion has a solids content between about 10% and about 50% and more preferably between about 20% and about 30%. "" "The preferred mode of this P917 invention is characterized by having the reinforcing agent deposited on the surface which essentially covers the interior, complete surface on which it resides. A frequency of uniform deposits of the fluidized reinforcing agent at about 100 tanks per inch or more is sufficient to achieve this. Preferably, a frequency of between about 200 and about 1000 tanks per inch is desired. The term "frequency" in reference to the spacing of chemical softener deposits, as used herein, is defined as the number of deposits per linear inch as measured in the direction of the closest spacing. It is recognized that many patterns or arrangements of deposits qualify as being uniform and discrete and the spacing can be measured in several directions. For example, a rectilinear arrangement of deposits will be measured as having few deposits per inch in a diagonal line than in the horizontal and vertical lines. The inventors believe that the direction of the minimum spacing is the most significant and therefore they define the frequency in that direction. A common pattern of engraving is the pattern called "hexagonal" in which the hollowed out areas are recorded in centers that receive in the P917 corners of an equilateral hexagon with a recessed, additional area in the center of the hexagonal figure. It is recognized that the closest spacing for this arrangement is along a pair of lines crossing each other at 60 ° and each crossing a horizontal line at 60 °. The number of cells per square area in a hexagonal array is thus 1.15 times the square of the frequency. Uniform deposits on the surface of the fluidized strengthening agent are preferably less than about 250 microns in diameter, more preferably less than about 150 microns in diameter, and most preferably less than about 50 microns in diameter. The size of the reservoirs noted above refers to the size of the fluidized reinforcing agent at the moment of contact with the tissue paper web. It should be recognized that the preferred fluidized reinforcing agents have a viscosity and surface tension that stimulate packing once applied to the substrate. In this way, it is believed that the area covered by the reinforcing agent is greater than that predicted by the deposit frequency and deposit size ranges, specified hereinbefore.

P917 In fact, the entire surface will be substantially covered by the reinforcing agent in the preferred embodiment of the present invention. The present invention is further characterized by having the uniform surface deposits residing predominantly in at least one and more preferably in both, of the two inner surfaces of a two-sheet multi-sheet tissue paper product. The tissue paper webs of the present invention can be bonded together either by means of the reinforcing agent or by other means; if these bonds are present, they should not be formed over the majority of the surface of the webs in order to maintain a sliding plane between the tissue paper webs comprising the multi-ply tissue paper product of the present invention. A particularly effective means to achieve this is to deposit the reinforcing agent, fluidized in a non-uniform manner. The non-uniform application, particularly preferred, is characterized by having the agent deposited in such a way that a scattered, uniform pattern in relatively concentrated areas of the fluidized reinforcing agent is deposited within a relatively diffuse pattern, uniformly P917 applied from the fluidized reinforcing agent and wherein the combining step and the process of the present invention is carried out by applying a combination pressure sufficient to substantially join a weft of tissue paper reinforced on the surface to a tissue paper web, additional, by the union via the concentrated areas of the reinforcing agent. The combination pressure is selected to be insufficient to effect bonding by the areas of the reinforcing agent residing in the uniform, relatively diffuse field.The relatively diffuse pattern of the fluidized reinforcing agent is characterized by essentially covering the inner surface, The entirety in which it resides As previously noted herein, a spacing of uniform reservoirs of the reinforcing agent, fluidized to approximately 100 tanks per inch or more is sufficient to accomplish this, preferably a spacing of between about 200 and about 1000 tanks per inch is desired, Also, as noted hereinabove, the uniform, fluidized, reinforcing agent surface deposits are preferably less than about 250 microns in diameter, so P917 more preferably less than about 150 microns in diameter, most preferably less than about 50 microns in diameter, wherein the specified diameters refer to the size of the deposits of the reinforcing agent, fluidized at the instant of contact with the screen of tissue paper. In contrast, the relatively uniform, scattered pattern of the relatively concentrated areas of the fluidized reinforcing agent is characterized by covering only a minor portion of the inner surface in which it resides. A frequency of uniform deposits of the fluidized reinforcing agent comprising the pattern spread to at least about 2 tanks per inch is sufficient to accomplish this. Preferably, a frequency of between about 0.2 and about 1 deposit per inch is desired. The uniform surface deposits of the fluidized reinforcing agent in the spread pattern are preferably greater than about 1000 microns in diameter, more preferably greater than about 2500 microns in diameter, and most preferably greater than about 5000 microns in diameter. diameter. The size of the deposits indicated above refers to the P917 size of the fluidized reinforcing agent at the instant of contact with the tissue paper web. It should be recognized that the preferred fluidized reinforcing agents have a viscosity and surface tension that promotes retention once applied to the substrate. The area covered by the reinforcing agent in this manner is believed to be greater than that predicted by the intervals of deposit frequency and deposit size, specified hereinabove. However, the frequency and deposit size of the deposits that reside in the scattered pattern must be selected to minimize the "growth" of the deposit size, since the function of these deposits is to strictly promote an intermittent union of the deposits. sheets to the adjacent tissue paper plot instead of securing the sheets together in a complete manner. The multi-sheet tissue paper product of the present invention preferably has a basis weight between about 20 g / m2 and about 70 g / m2 and more preferably between about 25 g / m2 and about 50 g / m2. It has a density between about 0.03 g / cm3 and about 0.6 g / cm3 and more preferably between about 0.1 g / cm3 and 0.2 g / cm3.

P917 The soft tissue paper of the present invention additionally comprises fibers for the manufacture of paper of both types of hardwood as softwood in which at least about 50% of the fibers for papermaking are hardwood and at least about 10% are softwood. The hardwood and softwood fibers are more preferably isolated by relegating each to separate layers wherein the tissue paper webs comprising the multi-sheet tissue paper product have an inner layer and at least one outer layer. The tissue paper webs of the present invention are preferentially creped, that is, they are produced in a papermaking machine, culminating in a Yankee dryer to which a partially dry papermaking weft adheres, and on which it is dried and from which it is removed by the action of a knife. flexible Creping is a means to mechanically compact the paper in the machine direction. The result is an increase in the basis weight (mass per unit area) as well as dramatic changes in many physical properties, particularly when measuring the direction of the machine. Creping is generally achieved with a flexible blade, called a blade P917 scraper, against a Yankee dryer in an operation on the machine. A Yankee dryer is an overall drum of 8-20 feet in diameter, which is designed to be pressurized with steam to provide a hot surface to finish drying the papermaking wefts at the end of the papermaking process . The paper web that first forms in a carrier of foraminous formation, such as a Fourdrinier mesh, where it is freed from the copious water necessary to disperse the fibrous slurry, is generally transferred to a felt or tissue in a so-called press section where dewatering is continued either by mechanical compaction of paper or by some other dewatering method such as pass drying with hot air, before it is finally transferred in the semi-dry condition to the surface of the Yankee to be finish the drying. The most preferable variations of the creped papermaking process for making tissue paper useful in the present invention include so-called patterned densified methods in which the resulting structure is characterized as having a relatively high volume field of relatively low fiber density. and an arrangement of zones P917 densified from a relatively high fiber density dispersed within the high volume field. The high volume field is alternatively characterized as a field of cushion regions. The densified zones are alternatively referred to as knuckle regions. The densified zones can be discreetly spaced within the high volume field or can be interconnected, either completely or partially, within the high volume field. Preferably, the relatively high density areas are continuous and the high volume field is discrete. Preferred processes for making densified patterned tissue paper webs are described in U.S. Patent No. 3,301,746, issued to Sanford and Sisson on January 31, 1967, U.S. Patent No. 3,974,025, issued to Peter G. Ayers on August 10, 1976, and United States Patent No. 4,191,609, granted to Paul D. Trokhan on March 4, 1980, and United States Patent No. 4,637,859, granted to Paul D. Trokhan on January 20, 1987, United States Patent No. 4,942,077 issued to Wendt et al. on July 17, 1990 all of which are incorporated herein by reference. To form the creped tissue paper webs, P917 densified in pattern, the transfer step of the weft immediately after forming the weft is for a training fabric instead of a felt. The plot is juxtaposed against an array of supports that comprise the training fabric. The screen is pressed against the array of supports, thereby resulting in densified zones in the frame at the locations corresponding geographically to the points of contact between the array of supports and the wet screen. The rest of the non-compressed frame during this operation is referred to as the high volume field. The high volume field can be further dedensified by the application of fluid pressure, such as with a vacuum-type device or a pass-through blowing device. The web is drained, and optionally pre-dried, in such a way as to substantially avoid understanding the high volume field. This is preferably achieved by the fluid pressure, such as with a vacuum-type device or a blow-through dryer, or alternatively by mechanically pressing the weft against an array of supports where the high-volume field is not compressed . The operations of dewatering, optional pre-drying and formation of densified zones can be integrated or partially integrated P917 to reduce the total number of processing steps performed. The moisture content of the semi-dry web at the point of transfer to the Yankee surface is less than about 40% and the hot air is forced through the semi-dry web while. The semi-dry weave is in the forming fabric to form a low density structure. The pattern densified pattern is transferred to the Yankee dryer and dried until completion, still avoiding mechanical pressing in a preferred manner. In the present invention, preferably from about 8% to about 55% of the tissue paper surface, creped comprises densified knuckles having a relative density of at least 125% of the density of the high volume field. The arrangement of supports is preferably a stamping carrier fabric having a knuckle pattern shift that operates as the arrangement of supports that facilitates the formation of the densified zones in the application of pressure. The knuckle pattern constitutes the arrangement of supports previously referred to. Embossing fabrics are disclosed in U.S. Patent No. 3,301,746 to Sanford and Sisson, issued January 31, 1967, U.S. Pat. No. 3,821,068 to U.S. Pat.

P917 Salvucci Jr. Et al., Issued May 21, 1974, U.S. Patent No. 3,974,025 to Ayers, issued August 10, 1976, U.S. Patent No. 3,573,164 to Friedberg et al., Issued March 30. of 1971, U.S. Patent No. 3,473,576 to Amneus issued October 21, 1969, U.S. Patent No. 4,239,065 to Trokhan, issued December 16, 1980, and U.S. Patent No. 4,528,239 to Trokhan granted on July 9, 1985, all of which are incorporated herein by reference. More preferably, the embryonic mesh is made to fit the surface of an open mesh drying / printing fabric with application of a fluid resistance to the weft and subsequently thermally pre-dried in the fabric as part of a process of making low density paper. When thermal pre-drying is carried out by passing warm air through the embryonic mesh, the process is referred to in the art as "pass-through" drying. Fields dried with pass-through air are particularly preferred for use in the present invention. The advantages of the present invention will be realized to the greatest possible extent when the fabric of P917 drying or stamping described herein in the above manner is one that is characterized by having high density continuous areas ("knuckle"), dispersed within a high volume field. Preferably, areas of a relatively high volume of a differential density structure are discrete regions referred to as "cushions" herein. When the drying or embossing fabric comprises continuous knuckle or high density areas, the cushions are necessarily discrete. The frequency of the cushions in a given area of the tissue paper is significant. It is desirable to maintain as high a level of cushions as possible for maximum volume and visibility of the pattern of embossing fabric. However, excessive size can significantly detract from smoothness due to the negative points of the textured surface coarser. Another variation of the processing steps included within the present invention includes the formation of multilayer, non-densified tissue paper structures, called non-compacted, as described in United States Patent No. 3,812,000 issued to Joseph L. Salvucci, Jr. and Peter N. Yiannos on May 21, 1974 and U.S. Patent No. 4,208,459, P917 granted to Henry E. Becker, Albert L. McConnell, and Richard Schutte on June 17, 1980, both of which are incorporated herein by reference. In general, multilayer, non-densified, non-compacted tissue paper structures are prepared by depositing a papermaking raw material into a foraminous forming mesh such as a Fourdrinier mesh to form a wet weft, draining the weft and remove the additional water without mechanical compression until the weft has a fibrous consistency of at least 80% and the plot is woven. The water is removed from the weave by vacuum dewatering and. thermal drying. The resulting structure is a high volume, soft but weak sheet of relatively non-compacted fibers. The bonding material is preferably applied to the portions of the weft before creping. So much so that the characteristics of the creped paper webs, particularly when the creping process is preceded by pattern densification methods, are preferred to practice the present invention, the non-creped tissue paper is also a satisfactory substitute and the practice of the present invention using non-creped tissue paper is specifically incorporated within the scope of the present invention.

P917 invention. Uncreated tissue paper, a term as used herein, refers to tissue paper that is dried noncompressively, more preferably by pass drying. The resulting dried-out patches are densified in a pattern such that areas of relatively high density are dispersed within a high-volume field, including pattern-densified tissue in which the relatively high density areas are continuous and the high volume field is discrete. In order to produce the undrawn tissue paper webs, an embryonic web is transferred from the foraminous forming carrier in which it is, to a carrier carrier of high fiber content, which moves slower. The weft is then transferred to a drying fabric in which it is dried to a final dryness. These webs may offer some advantages in surface smoothness compared to creped paper webs. Techniques for producing tissue without creping in this manner are taught in the prior art. See for example, Wendt et al. in European Patent Application 0 677 612A2, published on October 18, 1995 and incorporated herein by reference, teaches a P917 method for making soft tissue paper products without creping. In another case, Hyland et al., In European Patent Application 0 617 164 Al, published September 28, 1994 and incorporated herein by reference, teaches a method for making dry, smooth, creped leaves. Figures 1-7 are presented as an assistance in the understanding of the present invention. Figure 1 is an elevation, side view of a photo etched combination and stamping arrangement illustrating the method for forming the multi-sheet tissue paper product comprising the reinforcing agent deposited on the surface of the present invention. The process depicted in Figure 1 applies the reinforcing agent to a surface of the tissue paper web by an indirect gravure printing method. With reference to Figure 1, the fluidized reinforcing agent 6 is shown in a tub 5, such that the rotary engraving roller 4 is partially immersed in the fluidized reinforcing agent 6. The engraving roller 4 has a plurality of recessed areas that are substantially hollow in contents when they enter the tub 5, but P917 charged with the fluidized reinforcing agent 6 as the engraving roller 4 becomes partially immersed in the fluidized reinforcing agent in the tub 5 during the rotation of the roller. With reference still to Figure 1, the fluidized reinforcing agent 6 which is collected from a tub 5, but is not maintained in the recessed areas is removed by the flexible scraper blade 7, which makes contact with the engraving roller 4 in its outer surface, but is unable to deform significantly in hollowed areas. Therefore, the remaining fluidized reinforcing agent in the engraving roller 4 resides almost exclusively in the recessed areas of the engraving roller 4. This remaining fluidized reinforcing agent is transferred in the form of deposits to the applicator roll. 3. The applicator roll 3 may have any of a variety of surface coatings with the condition that they are suitable for the purpose of the process. More commonly, the applicator roll 3 in this embossing arrangement will be covered with an understandable cover such as an elastomeric polymer such as a natural or synthetic rubber. The engraving roller 4 and the applicator roller 3 will normally operate with interference since they have a charging pressure P917 which will aid in the extraction of the fluidized reinforcing agent in the recessed areas of the engraving roll as they pass successively through the area 8 formed by interference of the engraving roll 4 and the applicator roll 3. The actual interference or contact between the surfaces of rollers in area 8 are usually preferred, but it is contemplated that certain combinations of size and shape of the recessed areas and fluidized characteristics of the reinforcing agent may allow satisfactory transfer by having only the two rollers passing within a close proximity . The fluidized reinforcing agent extracted in the area 8 from the engraving roll 4 to the applicator roll 3 takes the form of surface deposits corresponding in size and space to the pattern of the recessed areas of the engraving roll 4. reinforcement, fluidized in the applicator roller 3 are transferred to the tissue paper web 1, which is directed towards the area 9, an area stopped by the point at which the applicator roller 3, the tissue paper web 1, and the roller of print 2 are in the vicinity of each other. The printing roller 2 can have any of a variety of surface coatings with the condition that they are P917 suitable for the purpose of the process. More commonly, the printing roller 2 in this configuration will have a metallic covering. The printing roller 2 and the applicator roller 3 will operate normally without interference. It is only necessary to make the rollers pass in a sufficiently close way to each other in such a way that when the tissue paper web 1 is present in the area 9, the tissue paper web 1 contacts the reservoirs of the reinforcing agent, fluidized in the applicator roller 3 in a manner sufficient to cause them to be transferred at least partially from the applicator roller 3 to the tissue paper web 1. Since the loading pressure between the applicator roller 3 and the printing roller 2 will tend to compress the tissue paper web 1, excessively small separations between the two rollers must be avoided in order to preserve the volume thickness of the web 1 tissue paper. Actual interference or contact between the surfaces of the rollers (through the tissue paper web 1) in the area 9 is usually not necessary, but it is contemplated that certain combinations of patterns and fluidized characteristics of the reinforcing agent may require that the Two rollers operate in contact or with each other. The tissue paper web 1 leaves the area 9 with the side 11 P917 containing the surface deposits of the reinforcing agent. The tissue paper web 10 is the tissue paper web 1 that came out of the area 9 on the side 11 that contains the surface deposits of the reinforcing agent. With reference still to Figure 1, the tissue paper web 10 and the tissue paper web 13 are directed towards, and combined in, the area 12, an area defined by the point at which the two combining rollers 14, the The tissue paper 10 and the tissue paper web 13 are in the vicinity of each other. The combiner rollers 14 may have any of a variety of surface coverages provided they are suitable for the purpose of the process. More commonly, one of the combiner rollers 14 will be covered in an understandable cover such as an elastomeric polymer such as a natural or synthetic rubber, while the other combiner will have a metal cover. A fixed gap, which is less than the sum of the thickness of the tissue paper web 10 and the tissue paper web 13, between the combining rollers 14 in the area 12 is preferred, such that the attachment of the sheets is achieved. as the multi-sheet tissue paper product 15 leaves the area 12. Although it is contemplated that certain combinations of the P917 characteristic of the tissue paper web and the surface characteristic of the combiner roller can allow the satisfactory joining of the sheets and the satisfactory thickness of the multi-sheet tissue paper product with an interference of the combining rollers 14. The Figure 2 is an elevation, side view of a photo etched combination and stamping arrangement illustrating the method for forming the multi-sheet tissue paper product comprising the reinforcing agent deposited on the surface of the present invention. The process depicted in Figure 2 applies the reinforcing agent to a surface of the tissue paper web by a direct gravure printing method. With reference to Figure 2, the fluidized reinforcing agent 25 is shown in a tub 24, such that the rotary engraving roller 26 is partially immersed in the fluidized reinforcing agent 25. The engraving roller 26 has a plurality of recessed areas which are substantially hollow in contents when they enter the tub 24, but are filled with the reinforcing agent 25, fluidized as the engraving roller 26 becomes partially immersed in the coating agent.

P917 reinforcement, fluidized in the tub 24 during roll rotation. With reference still to Figure 2, the excess fluidized reinforcing agent 25 that is collected from the tub 24, but not held in the recessed areas is removed by the scraper flexible blade 23, which makes contact with the roller. engraved 26 on its outer surface, but is unable to deform significantly in the recessed areas. Therefore, the remaining fluidized reinforcing agent in the engraving roller 26 resides almost exclusively in the recessed areas of engraving roll 26. The remaining, fluidized reinforcing agent is transferred in the form of deposits to the weft 20 of tissue paper, which is directed towards the area 22. The transfer occurs because the tissue paper web 20 is placed in the vicinity of the reinforcing agent, or fluidized present in the recessed areas, due to the coaction of the printing roller 21 relative to the engraving roll 26 in the area 22. The printing roller 21 may have any of a variety of surface coatings on the condition that they are suitable for the purpose of the process. More commonly, the printing roller 21 will be covered with a cover P917 compressible such as an elastomeric polymer such as natural or synthetic rubber. The engraving roller 26 and the printing roller 21 will normally operate with interference, that is, they will be in contact through the tissue paper web 20, since they have a loading pressure which will aid in the extraction of the fluidized strengthening agent from the recessed areas of the engraving roll 26 as they pass successively through the area 22 formed by the interference of the engraving roll 26, the weft 20 of tissue paper, of the printing roller 26. Usually an interference or actual contact between the surface of the rollers transmitted through the tissue paper 20 in the area 22 is preferred, but it is contemplated that certain fluidized characteristics could allow the transfer satisfactory only by having the two rollers and the confined tissue paper run within close proximity. The tissue paper web 20 leaves the area 22 with the area 27 containing the surface deposits of the reinforcing agent. The tissue paper web 28 and the tissue paper web 20 that left the area 22 with the area 27 containing the surface deposits of the reinforcing agent. With reference still to Figure 2, the frame 28 P917 of tissue paper and the tissue paper web 30 are directed towards and combined in area 29, in an area defined by the point at which the two combining rollers 31, the tissue paper web 28, and the weft 30 Tissue paper are in the vicinity of each other. The combiner rolls 31 may have any of a variety of surface coatings provided they are suitable for the purpose of the process. More commonly, one of the combiner rollers 31 will be covered with an understandable cover such as an elastomeric polymer such as a natural or synthetic rubber, while the other combiner roller will have a metal cover. A fixed gap, which is less than the sum of the thickness of the tissue paper web 28 and the tissue paper web 30, between the combinator rollers 31 in the area 29 is preferred, such that the attachment of the webs is achieved as the multi-sheet tissue paper product 32 leaves the area 29. But, it is contemplated that certain combinations of the tissue paper web characteristic and the surface characteristic of the combiner roller may allow satisfactory bonding of the sheets and the satisfactory thickness of the product 32 of multi-sheet tissue paper with an interference between the combining rollers 31.

P917 Figure 3 is an elevation, side view of a photo etched combination and stamping arrangement illustrating the method for forming the multi-sheet tissue paper product comprising the reinforcing agent deposited on the surface of the present invention. The process depicted in Figure 3 applies the reinforcing agent to a surface of the two tissue paper webs by a direct gravure printing method, which is then combined to form a multi-sheet tissue paper product. With reference to Figure 3, the fluidized strengthening agent 66 is shown in a tub 65, such that the rotary engraving rolls 64 are partially subjected to the fluidized strengthening agent 66. The engraving rolls 64 have a plurality of recessed areas which are substantially hollow in contents when they enter the tubs 65, but are filled with the fluidized reinforcing agent 66 as the engraving rollers 64 become partially immersed in the agent of reinforcement, fluidized in the vats 66 during the rotation of the rollers. Still with reference in Figure 3, the reinforcing agent 66, fluidized, in excess which P917 collects from the vats 65, but is not maintained in the recessed areas, scrapers are removed by the flexible blades 67, which contact the engraving rolls 64 on the outer surface, but are unable to deform significantly in the areas cupped Therefore, the fluidized reinforcing agent remaining in the engraving rolls 64 resides almost exclusively in the recessed areas in the engraving rolls 64. This remaining fluidized reinforcing agent is transferred to the form of weft deposits. 61 of tissue paper, which are directed towards the areas 69. The transfer occurs because the tissue paper webs 61 are placed in the vicinity of the fluidized reinforcing agent, present in the recessed areas due to the coaction of the rollers of the tissue. printing 62 relative to the engraving rollers 67 in the areas 69. The printing rollers 62 can have any of a variety of surface coatings on the condition that they are suitable for the purpose of the process. printing 62 will be covered with a compressible cover such as an elastomeric polymer such as a natural or synthetic rubber. 62 printing will operate normally with interference, P917 ie they will be in contact through the tissue paper webs 61, since they have a loading pressure that will aid in the extraction of the reinforcing agent, fluidizing the recessed areas of the engraving rollers 67 as they pass successively through the areas 69 formed by the interference of the engraving rollers 67, the tissue paper webs 61, and the impression rollers 62. Interference in contact Actual between the surfaces of the rollers transmitted through the tissue paper webs 61 in the areas 69 is usually preferred, but it is contemplated that certain fluidized characteristics may allow satisfactory transfer by only making the printing rollers 62, the rollers engraving 64, and the confined tissue paper webs pass within a close proximity. The tissue paper webs 61 exit the areas 69 with the area 71 that contains the surface deposits of the strengthening agent. The tissue paper webs 70 are the tissue paper webs 61 that come out of the areas 69 with the sides 71 containing the surface deposits of the strengthening agent. Referring still to Figure 3, the tissue paper webs 70 are directed towards and combined in the area 72, an area defined by the point at which the P917 two combiner rollers 74 and the tissue paper webs 70 are in the vicinity of each other. The combiner rolls 74 may have any of a variety of surface coatings provided they are suitable for the purpose of the process. Most commonly, one of the combiner rolls 74 will be covered with a compressible cover such as an elastomeric polymer such as a natural or synthetic rubber, while the other combiner roll will have a metal cover. A fixed spacing, which is less than the sum of the thickness of the tissue paper webs 70, between the combiner rollers 74 of the area 72 is preferred, so that the joining of the sheets according to the tissue paper product 73 is achieved. multiple sheets leave the area 72. But it is contemplated that certain combinations of the tissue paper web and the surface characteristic of the combiner roller may allow successful binding of the sheets and the satisfactory thickness of the multi-sheet tissue paper product 72. with an interference between the combiner rollers 74. FIG. 4 is a schematic, cross-sectional representation of the multi-sheet tissue paper product of the present invention illustrating the areas in which the excipient is present.

P917 reinforcement, deposited on the surface. With reference to Figure 4, the multi-sheet tissue paper comprises long fibers 82 and short fibers 83. Preferred long fibers 82 are soft northern wood kraft. Preferred short fibers 83 are eucalyptus. The inner zone 84 of the tissue paper web comprises long fibers 82, short fibers 83, and a reinforcing agent 81. The preferred side of the inner zone 84 of the tissue paper web is the side of the felt. The outer zone 85 of the tissue paper web comprises long fibers 82, short fibers 83, but is substantially free of the reinforcing agent. The preferred side of the outer tissue web 85 is the side of the mesh. The sheets of the multi-sheet tissue paper product are joined together by the reinforcing agent in the discrete, concentrated array 86, while substantially merging outside these areas. Figure 5 is a schematic representation illustrating the detail of the recessed areas for use in the embossing rolls illustrated in Figures 1, 2 and 3, ie, the engraving roll 4 of Figure 1, the engraving roll 26 of Figure 2, and the engraving roll 64 of Figure 3. With reference to Figure 5, the roll of P917 engraving 75 has a plurality of recessed areas sometimes referred to as cells. The recessed areas 76 and 77 exist on an otherwise smooth roller surface. With reference still to Figure 5, the roller 75 may be comprised of a variety of materials. In general, it will be relatively non-compressible in nature such as a ceramic metal roll, but roller elastomeric covers are also possible. With reference still to Figure 5, more preferably, the surface of the roll 75 is ceramic such as aluminum oxide. This allows the creation of the plurality of recessed areas when stamping them by directing an intense laser beam on the surface as is well known in the stamping process industry. Referring still to Figure 5, an alternative means for creating the recessed areas in the roll 75 is to be electro-mechanically stamped using an electronically controlled oscillation of a diamond tipped cutting tool. When this method is selected, it is more convenient to cover the roll surface with copper until it is stamped, then veneer a thin chrome finish to P917 protect the soft copper layer. Referring still to Figure 5, an alternative means for creating recessed areas in roll 75 is to etch them chemically using a labile roller surface protected by a chemically resistant mask secured to the surface of the roll to prevent etching in unproposed areas. to take areas 76 and 77. When this method is selectedIt is again more convenient to smooth the roll with copper coating until it is engraved and then to veneer a thin chrome finish to protect the soft copper layer. Referring still to Figure 5, an alternative means for creating the recessed areas of the roll 75 is to mechanically stamp them using a knurled cutting tool. This method allows the widest variety of construction materials for the roller but suffers from little possible variation in the achievable patterns. With reference still to Figure 5, the smaller but more frequent recessed areas 76 are useful in applying the reinforcing agent of the present invention in a relatively diffuse pattern. The larger but less frequent hollow areas 77 are useful for applying the agent of P917 reinforcement of the present invention in a discrete, scattered pattern to promote adhesion of the tissue paper web to an adjacent tissue paper web. Figure 6 is a scan electron micrograph of the felt side of a tissue paper web comprising long fibers, short fibers, and the reinforcing agent applied on the surface. The reinforcing agent appears as a coating on the fibers, encapsulating the fibers. The fibers in Figure 6 comprise the felt side of the tissue paper web. The felt side of the tissue paper web in Figure 6 was applied to the surface with a reinforcing agent. Figure 7 is a scanning electron micrograph of the cross section of a tissue paper web comprising long fibers, short fibers, and the reinforcing agent applied to the surface. The reinforcing agent appears as a coating on the fibers in the upper part of Figure 7, welding together the fibers. The fibers in the upper part of Figure 7 comprise the felt side of the tissue paper web. The felt side of the tissue paper web in Figure 7 was applied to the surface with a reinforcing agent.

P917 The reinforcing agent remains substantially absent from the fibers in the lower part of Figure 7. The fibers in the lower part of Figure 7 comprise the mesh side of the tissue paper web. The mesh side of the tissue paper web in Figure 7 was not applied to the surface with a reinforcing agent. It is anticipated that wood pulp in all its varieties will normally comprise tissue paper with utility in this invention. However, other cellulose fibrous pulps such as cotton fluff, bagasse, rayon, etc., can be used, and none is known. Wood pulps useful herein include chemical pulps such as sulphite and sulfate pulps (sometimes called Kraft pulps) as well as mechanical pulps including, for example, ground wood, Thermo-Mechanical Pulp (TMP) and Chemo-ThermoMechanical Pulp (CTMP). ). Pulps derived from both deciduous and coniferous trees can be used. Both hardwood pulp and soft wood pulp, as well as combinations of the two can be used as papermaking fibers for the tissue paper of the present invention. The term "hardwood pulps" as used herein refers to the fibrous pulp derived from the P917 wood substance of deciduous trees (angiosperm), while "soft pulp" are fibrous pulps derived from the wood substance of conifer trees (gymnosperms). Mixtures of hardwood kraft pulp, especially eucalyptus, and northern softwood kraft pulp (NSK) are particularly suitable for making the tissue paper webs of the present invention. A preferred embodiment of the present invention comprises the use of tissue paper webs, in layers wherein, more preferably, hard wood pulps such as eucalyptus are used for the layer (s) which will comprise exterior surfaces of the multi-sheet tissue paper product and wherein the northern softwood kraft pulps are used for the layer (s) which will comprise the inner surfaces of the multi-sheet tissue paper product. The fibers derived from recycled paper, which may contain any or all of the above categories of fibers, are also applicable to the present invention.

Optional Chemical Additives Other materials can be added to the aqueous papermaking raw material or the embryonic web to impart other characteristics to the P917 product, or improve the papermaking process as long as they are compatible with the chemistry of the reinforcing agent and do not significantly and adversely affect the softness or character of the strength of the present invention. The following materials are implicitly included, but its inclusion is not presented to be exhaustive. Other materials may be included as long as they do not interfere or counteract the advantages of the present invention. It is common to add a kind of cationic charge alteration to the papermaking process to control the Z potential of the aqueous papermaking raw material as the papermaking process is distributed. These materials are used because most of the solids in nature have negative surface charges, including the surfaces of cellulosic fibers and fine particles and most inorganic fillers. A kind of alteration of the cationic charge, traditionally used is alum. More recently in the art, the alteration of the charge is made by the use of synthetic, cationic, and relatively low molecular weight polymers that preferably have a molecular weight of no more than about 500,000 and more preferably, no P917 more than about 200,000, or even about 100,000. The charge densities of these synthetic, cationic, low molecular weight polymers are relatively high. These charge densities range from about 4 to about 8 equivalents of cationic nitrogen per kilogram of the polymer. One example material is Cypro 514R, a product of Cytec, Inc. of Stanford, C. The use of these materials is implicitly permitted within the practice of the present invention. The use of high cationic charge, high surface area microparticles for the purposes of improving formation, drainage, strength and retention is taught in the art. See, for example, U.S. Patent No. 5,221,435, issued to Smith on June 22, 1993, incorporated herein by reference. Common materials for this purpose are colloidal silica, or bentonite clay. The incorporation of these materials is implicitly included within the scope of the present invention. While the essence of the present invention is the presence of a reinforcing agent composition, deposited preferentially in the form of closely spaced, discrete deposits P917 on the inner surface of the multi-sheet tissue paper product, the invention also implicitly includes variations in which reinforcing, chemical agents are added as a part of the papermaking process. For example, if a permanent wet strength is desired, the group of chemical products can be added to the papermaking raw material or to the embryonic web: including polyamide-epichlorohydrin, polyacrylamides, styrene-butadiene latexes; polyvinyl alcohol not solubilized; urea-formaldehyde; polyethyleneimine; chitosan polymers and mixtures thereof. Polyamide-epichlorohydrin resins are cationic wet strength resins that have been found to be of particular utility. Suitable types of these resins are described in U.S. Patent No. 3,700,623, issued October 24, 1972 and 3,772,076 issued November 13, 1973, both issued to Keim and both are incorporated herein by reference. A commercial source of useful polyamide-epichlorohydrin resins is Hercules, Inc. of Wilmington, Delaware, which markets this resin under the trademark Kymene 557HR. Many paper products must have P917 resistance limited when wet due to the need to dispose of them through toilets in septic or sewer systems. If wet strength is imparted to these products, it is preferred that it be a fleeting wet strength characterized by a decay of the part or all of its potency upon standing in the presence of water. If a wet strength or gas is desired, the binder materials may be selected from the group consisting of dialdehyde starch or other resins with aldehyde functional groups such as Co-Bond 1000R offered by the National Starch and Chemical Company, Parez 750R offered by Cytec from Stanford, CT, and the resin described in U.S. Pat. 4,981,557 granted on January 1, 1991, to Bjorkquist and incorporated herein by reference. If improved absorbency is needed, surfactants can be used to treat the tissue paper webs of the present invention. The level of the surfactant, if used, is preferably from about 0.01% to about 2.0% by weight, based on the dry weight of the tissue paper fiber. The surfactants preferably have alkyl chains with eight or more carbon atoms. Anionic surfactants, from P917, for example, are linear alkyl sulfonates and alkylbenzene sulphonates. Exemplary nonionic surfactants are alkyl glycosides including alkylglycoside esters such as Crodesta SL-40R which is available from Croda, Inc. (New York, NY); alkyl glycoside ethers as described in U.S. Patent No. 4,011,389, issued to W. K. Langdon et al. March 8, 1977; and polyethoxylated alkyl esters such as Pegosperse 200 ML available from Glyco Chemicals, Inc. (Greenwich, CT) and IGEPAL RC-520R available from Rhone Poulenc Corporation (Cranbury, NJ). The chemical softening agents can also be included either by the wet end addition, the embryonic web or via methods of adding to the tissue web after it has dried. Preferred chemical, softening agents comprise quaternary ammonium compounds including, but not limited to, well-known dialkylmethylammonium salts (eg, ditallowdimethylammonium chloride, ditallowdimethylammonium methylsulfate, hydrogenated tallow dimethyl ammonium chloride, etc.). Particularly preferred variants of these softening agents are those which are considered to be variations of mono- or di-ester of the dialkyldimethylammonium salts mentioned with P917 anteriority. These include the so-called diester-di-dimethyl-ammonium chloride, diester-distearyl-dimethyl-ammonium chloride, monoester-di-dimethyl-ammonium chloride, diester-di (hydrogenated) methylsulfate tallow-dimethyl-ammonium chloride, diester-di (hydrogenated) tallow-dimethyl-ammonium, monoester-di (hydrogenated) chloride tallow-dimethyl-ammonium, and mixtures thereof, with variations of diester di (non-hydrogenated) chloride tallow-dimethyl-ammonium , Di Chloride (Hydrogenated to the Touch) Sebo-DiMetil-Ammonium (DEDTHTDMAC) and Di (Hydrogenated) Sebo-Dimethyl Ammonium Chloride (DEDHTDMAC), and mixtures thereof which are especially preferred. Depending on the characteristic requirements of the product, the saturation level of the design can be made from non-hydrogenated (soft) to partially or completely hydrogenated (hard) to the touch. The use of the quaternary ammonium ingredients as described hereinbefore is most effectively achieved if accompanied by an appropriate plasticizer. The plasticizer can be added during the quaternization step in the manufacture of the quaternary ammonium ingredient or it can be added subsequently. The plasticizer is characterized for being P917 substantially inert during chemical synthesis, but acts as a viscosity reducer to aid in subsequent synthesis and handling, i.e., the application of the quaternary ammonium compound to the tissue paper product. Preferred plasticizers are comprised of a combination of a non-volatile polyhydroxy compound and a fatty acid. Preferred polyhydroxy compounds include glycerol and polyethylene glycols having a molecular weight of from about 200 to about 2000, with polyethylene glycol having a molecular weight of from about 200 to about 600 which are particularly preferred. Preferred fatty acids comprise linear or branched and saturated or unsaturated analogs of 6 to 23 carbon atoms, with the isostearic acid being the most preferred. Another class of chemical softening agents, preferred, comprises the polydimethyl siloxane, organo-reactive, well-known ingredients, including the most preferred polydimethylsiloxane, amino functional. A particularly preferred form of the silicone softening agent will be to combine the organo-reactive silicone with a suitable quaternary ammonium compound. In this modality, the organ- Functional P917 is preferred to be an amino-polydimethylsiloxane and is used in an amount ranging from 0 to about 50%, with a preferred use in the range of about 5% to about 15%. The previous percentages represent the weight of the polysiloxane relative to the total weight of the softening agent, substantially attached. The fillers can also be incorporated into the tissue papers of the present invention. U.S. Patent No. 5,611,890, to Vinson et al., Issued March 18, 1997, and incorporated herein by reference discloses load-bearing tissue products, acceptable as substrates for the present invention. The above listings of the optional chemical additives are proposed by way of example only, and are not intended to limit the scope of the invention. The present invention is further applicable to the use of multilayer tissue paper webs. Multilayer tissue paper structures and methods for forming multilayer tissue paper structures are described in U.S. Patent No. 3,994,771 to Morgan, Jr. Et al., P917 issued November 30, 1976, United States Patent No. 4,300,981, to Carstens, issued November 17, 1981, United States Patent No. 4,166,001, Dunning et al., Issued August 28, 1979, and European Patent Publication No. 0 613 979 Al, by Edwards et al., published on September 7, 1994, all of which are incorporated herein by reference. The layers are preferably comprised of different types of fibers, the fibers which are typically relatively long softwood fibers and relatively short hardwood fibers as used in the manufacture of multilayer tissue paper. The most preferred multilayer tissue paper webs for use in the present invention comprise at least two superimposed layers, an inner layer and at least one outer layer contiguous with the inner layer. Preferably, the multilayer tissue paper web comprises two superposed layers, in an inner layer and an outer layer. The outer layer preferably comprises a primary constituent formed of filaments of relatively short papermaking fibers having an average fiber length between about 0.5 and about 1.5 mm, preferably less than about P917 1.0 mm. These papermaking fibers typically comprise hardwood fibers, preferably hardwood kraft fibers, and more preferably derived from eucalyptus. The inner layer preferably comprises a primary constituent formed of relatively long fiber filaments for the manufacture of paper having an average fiber length of at least about 2.0 mm. These long papermaking fibers are typically softwood fibers, preferably northern softwood kraft fibers. Single-ply or multi-ply tissue paper webs can be used to make the multi-ply tissue paper products of the present invention. In the typical practice of the present invention, a raw material in low consistency pulp is provided in a pressurized inlet box. The entrance box has an opening for distributing a thin deposit of pulp raw material on the Fourdrinier mesh to form a wet web. The web is then typically drained to a fiber consistency of between about 7% and about 25% (basis of total wet weight) by dewatering at P917 empty. To prepare the tissue paper products useful in the present invention, an aqueous papermaking raw material is deposited on a foraminous surface to form an embryonic web. The scope of the invention also includes processes for making the tissue paper product by forming multiple layers of paper in which two or more layers of the raw material are preferentially formed from the deposition of separate streams of dilute slurries. , fiber for example in a multi-channel input box. The layers are preferably comprised of different types of fiber, the fibers which are typically relatively long softwood fibers and relatively short hardwood fibers as used in the manufacture of multilayer tissue paper. If the individual layers are initially formed into separate meshes, the layers are subsequently combined when they are wet to form a multilayer tissue paper web. Papermaking fibers are preferably comprised of different types of fiber, fibers which are typically relatively long softwood fibers and hardwood fibers P917 relatively short. Preferably, the hardwood fibers comprise at least about 50% and the softwood fibers comprise at least about 10% of the fibers for papermaking. The term "strength" as used herein refers to the tensile strength, total specific, the determination method for this measurement is included in a later section of this specification. The tissue paper webs according to the present invention are strong. This generally means that their total tensile strength is at least about 200 g / inch, preferably more than about 400 g / inch. The multi-sheet tissue paper products of the present invention can be used in any application where multi-sheet, absorbent, soft tissue paper products are used. Particularly advantageous uses of the multi-sheet tissue paper products of this invention are in tissue paper products and facial tissues.

Analytical Procedures? _ Test A. Density The density of multilayer tissue paper, P917 as that term is used in the present, is the average density calculated as the basis weight of that paper divided by the thickness, with the appropriate unit conversions incorporated in the present. The thickness of the multilayer tissue paper, as used herein, is the thickness of the paper when it is subjected to a compressive load of 95 g / in2 (15.5 g / cm2).

B. Measurement of the Softness of the Tissue Papers by Panel Ideally, before the softness test, the paper samples to be tested should be conditioned according to the. Tappi method # T402OM-88. Here, the samples are preconditioned for 24 hours at a relative humidity level of 10 to 35% and within a temperature range of 22 to 402C. After this pre-conditioning step, the samples should be conditioned for 24 hours at a relative humidity of 48 to 52% and within a temperature range of 22 to 242C. Ideally, the softness panel test should be carried out within the limits of a quarter of constant temperature and humidity. If this is not convenient, all samples, including controls, must experience identical environmental exposure conditions.

P917 The softness test is performed as a paired comparison in a manner similar to that described in "Manual on Sensory Testing Methods," ASTM Special Technical Publication 434, published by the American Society for Testing and Materials 1968 and incorporated herein by reference. reference. Softness is evaluated by a subjective test using what is referred to as a Paired Difference Test. The method employs a standard external to the test material itself. For the softness perceived in tactile form, two samples are presented in such a way that the subject can not see the samples and the subject is asked to choose them based on the softness to the touch. The result of the test is reported in what is referred to as the Panel Score Unit (PSU). With respect to the softness test to obtain the softness data reported herein in PSU, a number of softness panel tests are performed. In each test, ten participants softness judges are asked to evaluate the relative softness of the three sets of paired samples. The pairs of samples are judged one pair at a time by each judge: a sample of each pair is designated X and the other is Y. Briefly, each sample X is awarded against its sample Y paired as follows: P917 1. a degree of plus one is given if X is judged to be a little softer than Y, and a degree of minus one is given if Y is judged to be a little softer than Y; 2. a degree of plus two is given if X is judged to be a little softer than Y, and a degree of minus two is given if Y is judged to be a little softer than X; 3. a degree of plus three is given to X if it is judged to be much softer than Y, and a degree of minus three is given if Y is judged as being much softer than X; and finally 4. a plus four degree is given to X if it is judged to be completely softer than Y, and a degree of minus 4 is given if Y is judged to be completely softer than X. The grades are averaged and the The resulting value is in units of PSU. The resulting data is considered the results of a panel test. If more than one pair of samples is evaluated then all pairs of samples are sorted into categories according to their grades by matched statistical analysis. Then, the category is changed up or down in value as required to give a PSU value of zero at which each sample is chosen for P917 do the standard on zero basis. The other samples then have values of more or less as determined by their relative degrees with respect to the zero-based norm. The number of panel tests performed and averaged is such that approximately 0.2 PSU represents a significant difference in subjectively perceived softness.

C. Measurement of Tissue Strength Resistance to Dry Stress Tension resistance is determined in strips of an inch of the sample using a Tension Resistance Tester Apparatus, standard Thwing-Albert Intelect II (Thwing-Albert Instrument Co., 10960 Dutton Rd., Philadelphia, PA, 19154). This method is proposed for use on finished paper products, spool samples, and uncovered goods.

Conditioning? _ Sample Preparation Before the stress test, the paper samples to be tested should be conditioned according to the Tappi method # T402OM-88. All paperboard and plastic packaging materials must be carefully removed from paper samples P917 before the test. The paper samples should be conditioned for at least two hours at a relative humidity of 48 to 52% within a temperature range of 22 to 242C. The preparation of the sample and all aspects of the stress test should also be carried out within the limits of the constant temperature and humidity room. For the finished product, any damaged product is discarded. Then, 5 strips of four useful units (also called leaves) are removed and stacked one on top of the other to form a long stack with the perforations between the matching sheets. Identify sheets 1 and 3 for the machine direction tension measurements and sheets 2 and 4 for the measurements in the transverse direction. Then, cut through the perforation line using a paper cutter (JDC-1-10 or JDC-1-12 with safety liner from Thwing-Albert Instrument Co., 10960 Dutton Road, Philadelphia, PA, 19154) to Prepare 4 separate materials. Make sure that batteries 1 and 3 are still identified for the test in the direction of the machine and batteries 2 and 4 are identified for the test in the transverse direction. Cut two strips 1 inch wide in the P917 machine direction of strips 1 and 3. Cut two strips 1 inch wide in the transverse direction of stacks 2 and 4. There are now four strips 1 inch wide for testing the tension in the direction of the machine and four 1-inch-wide strips for testing the tension in the transverse direction. For these finished product samples, the eight 1-inch wide strips are the thickness of five useful units (also called sheets). For unconverted material and / or spool samples, cut a 15"by 15" sample that is 8 sheets thick from a region of interest of a sample using a paper cutter (JDC-1-10 or JDC-1) -12 with safety lining by Thwing-Albert Instrument CO., 10960 Dutton Road, Philadelphia, PA, 19154). Make sure that a 15"cut runs parallel to the direction of the machine while the other runs parallel to the cross direction, ensuring that the sample is conditioned for at least 2 hours at a relative humidity of 48 to 52% and within a temperature range from 22 to 24 a.C. Sample preparation in all aspects of the stress test should also be carried out within the limits of the constant temperature and humidity room.

P917 From this 15"by 15" pre-conditioned sample that is 8 sheets thick, cut four 1"by 7" strips with the 7"long dimension running parallel to the machine direction. samples such as samples of unconverted material or reel of the machine direction Cut four additional strips of 1 inch by 7"with the dimension of 7" long that runs parallel to the transverse direction. Record these samples as samples of unconverted material or reel of the transverse direction Ensure that all previous cuts are made using a paper cutter (JDC-1-10 or JDC-1-12 with safety lining by Thwing-Albert Instrument Co., 10960 Dutton Road, Philadelphia, PA, 19154. There are now a total of eight samples, four 1"by 7" strips that are 8 sheets thick with the 7"dimension running parallel to the machine direction and four strips of 1"by 7" which are 8 sheets thick with the dimension of 7"which runs parallel to the transverse direction.

Appliance Operation Voltage Resistance Tester For the actual measurement of the voltage resistance, use a Resistance Tester Apparatus.

P917 Voltage, Normal, Albert Intelect II (Thwing-Albert Instrument Co., 10960 Dutton Rd, Philadelphia, PA, 19154). Insert the flat-face clamps into the unit and calibrate the tester according to the instructions given in the Thwing-albert Intelect II operations manual. Adjust the crosshead speed of the instrument to 4.00"/ min and the first and second lengths of the calibrator to 2.00". The sensitivity to break should be adjusted to 20.0 grams and the width of the sample should be adjusted to 1.00"and the thickness of the sample to 0.025". A load cell is selected in such a way that the predicted result of the voltage for the sample to be tested is between 25% and 75% of the range in use. For example, a 5000 gram load cell can be used for samples with a predicted voltage range of 1250 grams (25% of the 5000 grams) and 3750 grams (75% of the 5000 grams). The tensile tester apparatus should also be adjusted in the range of 10% with the 5000 gram load cell such that samples with predicted stresses of 125 grams to 375 grams can be tested. Take one of the tension strips and place one end of it on a clamp of the tensile strength tester. Place the other end of P917 the paper strip on the other clip. Make sure that the dimension along the strip is running parallel to the sides of the tensile tester apparatus. Also make sure that the strips are not loose on either side of the two clamps. In addition, the pressure of each of the clamps must be in total contact with the paper sample. After inserting the paper test strip into the two clamps, the tension of the instrument can be monitored. If a value of 5 grams or more is shown, the sample is too tight. Conversely, if a period of 2-3 seconds elapses after the start of the test before any value is recorded, the tension strip is too loose. Start the voltage resistance tester as described in the instrument manual of the tensile strength tester. The test is finished after the crosshead automatically runs to its starting position. Read and record the load to the voltage in units of grams from the scale of the instrument or the digital panel meter to the nearest unit. If the reset condition is not performed automatically by the instrument, perform the necessary adjustment to adjust the clamps of the instrument.

P917 instrument to its initial starting positions. Insert the next paper strip into the two clamps as described above, and get a reading of the tension in units of grams. Obtain the tension readings of all the paper test strips. It should be noted that the readings should be rejected if the strip slips or breaks on or near the edge of the clamps while the test is being performed.

Calculations: For the strips of the finished product in 1"width, in the direction of the machine, add the four recorded, individual tension readings Divide this sum by the number of strips tested.This number should normally be four. Also divide the sum of the tensions recorded between the number of useful units by tension strips.This is normally five for products of 1 sheet and 2 sheets.Repeat this calculation for the strips of the finished product in the cross section. converted or the spool samples cut in the machine direction, add the four recorded voltage readings, P917 individual. Divide this sum by the number of strips tested. This number should normally be four. Also divide the sum of the voltages recorded by the number of useful units per voltage strip. This is normally eight. Repeat this calculation for reel or non-converted sample paper strips in the transverse direction. All results are in units of grams / inch.

EXAMPLES The following examples are offered to illustrate the practice of the present invention. These examples are proposed to aid in the description of the present invention, but in no way should they be construed as limiting the scope thereof. The present invention is linked only by the appended claims.

Example 1 This example illustrates the use of a gravure stamper, direct to prepare a two-ply bath tissue paper having a reinforcing agent on the inner surface of a sheet.

P917 Agents used in the preparation of the fluidized reinforcing agent include Acrylic Latex (Rhoplex emulsion NW-2744F) of 45% solids from Rohm and Hass Company of Philadelphia, Pennsylvania. The fluidized reinforcing agent is prepared by mixing 50% acrylic latex and 50% tap water, resulting in a latex solids concentration of 23%. The fluidized reinforcing agent is then fed into an engraving tub which allows the fluidized reinforcing agent to fill the recessed areas of the rotating engraving roller. The surface of the engraving roller is coated with an aluminum oxide ceramic product in which the hollowed areas are engraved by a laser technique. The hollowed out areas are of hemispherical shape, each having a diameter of approximately 55 microns and therefore a depth of approximately 28 microns. The pattern of the recessed areas is hexagonal and the frequency of the recessed areas is approximately 350 areas per linear inch, such that there are approximately 140,000 recessed areas per square inch. The resulting percentage of the total area covered by the recessed areas is approximately 53%.

P917 The excess fluidized reinforcing agent is scraped from the surface of the engraving roller by a flexible PTFE scraper blade. The direct stamper is operated in such a way that the surface speed of its rollers and hence the tissue paper web speed is about 100 feet per minute. The engraving roller is operated in contact with the tissue paper web, which is in contact with the printing roller. The print roller has a rubber coverage of approximately a thick 50 P &J, which is 1/2 inch thick with an outside diameter of 4 inches. The two rollers are located in the interference in such a way that the width of the contact area of the two rollers by virtue of the deformation of the rubber covering on the printing roller when in the tissue paper web is not present is 5. / 32 of an inch. A web of tissue sheet bath approximately 10 mils thick is passed through the separation of the rollers formed between the etching roller and the printing roller where the fluidized transfer agent is transferred from the engraving roller to the tissue paper web. The tissue web leaving the roll separation formed by the engraving roller and the printing roller contains about 3% of the reinforcing agent (about 14% strengthening mixture) by weight. The resulting tissue paper web is combined with another tissue paper web of the same type that has not been modified by the gravure printing process of the present invention. The tissue web of two sheets, resulting becomes the rollers to toilet paper. The essential properties of the resulting tissue paper are measured and the following tables compare the strength and softness of Example 1 to Reference 1, a two-ply tissue paper product identical to Example 1, except that it does not incorporate the reinforcing agent deposited in the tissue. surface of the present invention.

P917 The resulting properties of Example 1 exhibit an increase in strength with only a relatively minor decrease in softness compared to the product of Reference 1 which does not incorporate the advantages of the present invention.

Example 2 This example illustrates the use of a gravure stamper, direct for preparing a two-ply bath tissue paper having a reinforcing agent on the inner surfaces of the two sheets. Agents used in the fluidized reinforcing agent preparation include acrylic latex (Rhoplex NW-1845 emulsion) of 44% solids from Rohm and Haas Company of Philadelphia, Pennsylvania. The fluidized reinforcing agent is prepared by using 50% acrylic latex and 50% tap water, resulting in a latex solids concentration of 22%. The fluidized reinforcing agent is then fed into an engraving vat which allows the fluidized reinforcing agent to be filled in the recessed areas of the rotating engraving roll. The surface of the engraving roll is coated with a ceramic product of aluminum oxide in which the hollowed areas are engraved by a laser technique. The hollowed out areas are formed hemispherically, each having a diameter of about 55 microns and therefore a depth of about 28 microns. The pattern of the recessed areas is hexagonal and the frequency of the recessed areas is approximately 350 areas per linear inch, such that there are approximately 140,000 recessed areas per square inch. The resulting percentage of the total area covered by the recessed areas is approximately 53%. The fluidized reinforcing agent is scraped off the surface of the washing roller P917 by a PTFE scraper blade, flexible. The direct stamper is operated in such a way that the speed of the surface of its rollers and therefore the speed of the tissue paper web is about 100 feet per minute. The engraving roller is operated in contact with the tissue paper web, which is in contact with the impression roller. The print roller has a rubber coating with a hardness of approximately 50 P &J, which is 1/2 inch thick with the outside diameter of 4 inches. The two rollers are loaded into the interference in such a way that the width of the contact area of the two rollers by virtue of the deformation of the rubber coating on the printing roller when the tissue paper web is not present is 5 / 32 of an inch. A weave of bath tissue paper and a sheet approximately 10 mils thick is passed through the separation of the rollers formed between the etching roller and the printing roller where the fluidized reinforcing agent is transferred from the engraving roller to the tissue paper web. The tissue web that comes out in the separation of the rollers formed by the engraving roller and the printing roller contains P917 about 4% reinforcing agent (approximately 18% strength, fluidized) by weight. The resulting tissue sheet of tissue paper is combined with another sheet of tissue paper, of a sheet, of the same type which has also been modified in a similar manner by the gravure printing process of the present invention. The tissue web of two sheets, resulting in rolls of toilet paper. The essential properties of the resulting tissue paper are measured and the following tables compare the strength and softness of Example 2 to a two-ply tissue paper product identical to Example 2, except that it does not incorporate the reinforcing agent, deposited on the surface of the tissue. present invention. Example 2 is also compared to a two-ply tissue paper product identical to that of Example 2, except that it does not incorporate the reinforcing agent deposited on the surface, but instead is strengthened by conventional means during the manufacture of the paper via a combination of increased refinement and the addition of dry strength at the wet end.

P917 The resulting properties of Example 2 exhibit an increase in strength with only a relatively minor definition in softness compared to the product of Reference 2A which does not incorporate the advantages of the present invention. The properties of Reference 2A illustrate that a product reinforced by a conventional means during papermaking can be made almost equal in strength to the product of Example 2, but the softness is degraded significantly by doing so.

P917

Claims (10)

1. CLAIMS; 1. A tissue paper product, multi-sheet, strong and smooth, the multi-sheet tissue paper product comprises at least two sheets in a face-to-face relationship, wherein each of the sheets has an inner surface facing the interior of the multi-sheet tissue paper product, characterized in that at least one of the inner surfaces of the sheets has a reinforcing agent deposited on the surface.
2. 2. The multi-sheet tissue paper product of claim 1, wherein the reinforcing agent is selected from the group consisting of starch, polyvinyl alcohol, polyamide resins, polyacrylamide resins, acrylic polymers, styrene-styrene copolymers. butadiene, vinyl acetate polymers, ethylene-vinyl acetate copolymers, vinyl chloride polymers, vinylidene chloride polymers, vinyl chloride-vinylidene copolymers, acrylonitrile copolymers, ethylene-acrylic copolymers and mixtures thereof .
3. 3. The multi-sheet tissue paper product according to claim 1 or 2, wherein the reinforcing agent comprises from about P917 0.5% to about 10% of the tissue paper product by weight based on the dry weight of the reinforcing agent compared to the dry weight of the multi-sheet tissue paper product.
4. 4. The multi-sheet tissue paper product according to any of the preceding claims, wherein the multi-sheet tissue paper product has two sheets.
5. The multi-sheet tissue paper product according to claim 4, wherein the sheets comprise a mesh side and a felt side wherein the felt area of both sheets is oriented such that they comprise inner surfaces of the product of multi-sheet tissue paper.
6. 6. The multi-sheet tissue paper product according to any of the preceding claims, wherein the reinforcing agent comprises an elastomeric polymer with a vitreous transition temperature between about -30 degrees C and about 10 degrees C.
7. 7. The product of multi-sheet tissue paper according to any of the preceding claims, wherein the sheets comprise tissue paper webs dried with passing air.
8. 8. A process to produce a product of P917 multi-sheet tissue paper, resistant and smooth, the process comprises the steps of: a) applying a reinforcing agent, fluidized on the surface of a tissue paper web by deposit on the surface thereby forming a tissue paper web , reinforced on the surface comprising from about 0.5% to about 10% of the reinforcing agent; and b) combining the reinforced tissue paper web on the surface of step (a) with at least one additional tissue paper web to form a multi-sheet tissue paper product, the combining step is characterized in that the reinforced tissue paper web on the surface it is oriented in such a way that the surface comprising the reinforcing agent forms an inner surface of the multi-leaf tissue paper product; wherein the multi-sheet tissue paper product comprises tissue paper webs that remain unbonded on at least a majority of the weft surface.
9. 9. The process according to claim 8, wherein the fluidized reinforcing agent is a P917 latex emulsion. The process according to claim 9, wherein the latex emulsion is stamped non-uniformly such that a non-scattered, uniform pattern of relatively concentrated latex areas is deposited within a relatively diffuse, uniformly applied emulsion pattern of latex and wherein combination step (b) is carried out by applying a sufficient combination pressure to substantially join the weft of tissue paper reinforced on the surface to the "additional tissue paper web by the union via the concentrated areas of the tissue. latex solids, the combination pressure that is insufficient to effect the bonding by the solid areas of latex residing in the relatively diffuse, uniform field. P917