MX2007008101A - Softening agent pre-treated fibers. - Google Patents

Abstract

A paper product includes fibers, such as cellulosic fibers, that are pre-treated with a softening agent. The softening agent is added to a fiber slurry and then is allowed to cure onto the fibers, typically by drying. The pre-treated fibers are then diluted, re-slurried, and incorporated into the fiber stream of a paper machine to form a fibrous web. The fibrous web can then be converted into a paper product, such as a personal care paper product, which exhibits improved softness with minimized slough.

Description

FIBERS TREATED PREVIOUSLY WITH SOFTENER AGENT Background The invention is generally concerned with paper products and the properties thereof. More particularly, in the manufacture of personal care products, such as facial tissues, bath tissues, napkins, wipes, and paper towels, it is often desired to optimize various properties related to aesthetics and performance. For example, personal care products should generally exhibit a soft feel, low detachment, good volume, and sufficient strength to perform the desired functions.

Unfortunately, when the steps are taken to increase one of these properties, other such properties may also be adversely affected. For example, softness is an important aesthetic property of many personal care paper products, so it is desirable in the art to develop products that exhibit improved softness. A conventional method to improve the softness in such products is to apply a binder chemical to the water-fiber suspension in the wet final section of the paper machine. Another conventional method is to spray such a chemical binder directly onto the fibrous tissue in the forming section of a paper machine. In any case, the chemical binder interrupts the bond that can normally take place between the fibers, which reduces all the resistance of the fibrous tissue. This reduction in resistance corresponds directly to an increase in softness.

However, this same reduction in strength also leads to an increase in detachment, which is generally undesirable for personal care products. For example, during processing and / or use, loose attached (for example, disbonded) fibers can be released from the paper product, thereby creating airborne fibers and fiber fragments. In addition, areas of fibers that are poorly bonded to each other but not adjacent to the fiber regions can be created that can break off from the paper surface and then be deposited on other surfaces, such as on human skin or clothing. Therefore, there is a desire for a paper product that exhibits Improved softness while minimizing the level of detachment.

Synthesis The invention is concerned with a paper product and the properties thereof. More particularly, the invention is concerned with a soft, low release paper product comprising at least an amount of cellulose fibers that have previously been treated with a softening agent, then allowed to cure, and then diluted and incorporated in a jet of water. fiber of the machine for paper. In one embodiment, the previous treatment fibers exhibit a Water Retention Value below 0.9 grams per gram. In another embodiment, the fibers have a degree of crimping that is less than 1.3.

The resulting paper product may comprise from about 10% to about 100% of previous treatment fibers, such as from about 10% to 50% of previous treatment fibers. The paper product may also comprise a single layer or multiple layers of fibers of previous treatment and / or untreated. In an incorporation, the Tensile strength of a fibrous fabric comprising fibers of previous treatment is reduced by 50% compared to the same fibrous tissue consisting of untreated fibers.

Numerous other features and advantages of the present invention will appear from the following description. In the description, reference is made to the accompanying drawings that help illustrate the exemplary embodiments of the invention. Such incorporations do not represent the entire scope of the invention. Reference should therefore be made to the claims herein to interpret the full scope of the invention.

Brief Description of the Drawings The foregoing and other features, aspects and advantages of the present invention will be better understood with respect to the following description, appended claims and drawings that are accompanied where: Figure 1 illustrates an incorporation of a dry liner machine that can be used for the prior treatment of the fibers with a softening agent; Figure 2 illustrates an embodiment of a paper machine that can be used to form a fibrous fabric comprising at least pre-treatment fibers made in accordance with the present invention; Figure 3 illustrates an embodiment of a main box that can be used in accordance with the present invention; Figure 4a illustrates an apparatus for testing detachment; Y Figure 4b is a perspective view of an abrasive spindle of Figure 4a.

The repeated use of reference characters in the present specification and drawings is intended to present the same or analogous features or elements of the invention.

DEFINITIONS It should be noted that, when used in the present description, the terms "comprises", "comprising" and other derivatives of the root term "understand" are intended for open terms that specify the presence of any characteristics, elements, integers, steps, or components, and are not limited to preventing the presence or addition of one or more other characteristics, elements, integers, steps, components, or groups thereof.

The terms "additive" and "chemical additive" refer to a single treatment compound or a mixture of treatment compounds.

The terms "cure", "cure", "curing" and other derivatives of the term "cure" refer to the drying of fibers that have previously been treated with a softening agent of the present invention in such a way that the softening agent is substantially adheres to and retains such fibers through a process to make paper and a process to convert paper. The dryness required to cure the softening agents in the fibers will vary depending on the softening agents used. However, in general, the fibers of previous treatment can be dried to a consistency of less than about 80% by weight.

The term "minor defects" refers to polymer / fiber bales that create the appearance of white spots within a fibrous tissue and / or paper product. These white spots will generally be in the order of one square millimeter in size or larger. A "minor defect count" refers to the number of minor defects found in a 7.5-inch by 7.5-inch sample of a fibrous tissue and / or paper product made from previously treated pulp fibers. The fibrous tissue and / or the paper product should have a count of defects of less than about 10 or less, more specifically about 5 or less, and even more specifically about about 3 or less.

The term "personal care paper product" is used herein to broadly include a tissue such as bath tissue, facial tissue, napkins, wipes, and towels, along with other cellulose structures including absorbent pads, tissue making liquids in absorbent articles such as diapers, bed pads, wet wipes, meat and poultry pads, feminine care pads, and the like in accordance with any conventional process for the production of such products. The term "paper" as used herein includes any fibrous fabric containing cellulose fibers alone or in combination with other fibers, natural or synthetic. A paper product can be layered or not in layers, creped, or not creped, and can comprise a single stratum or multiple strata. In addition, the paper product may contain reinforcing fibers for integrity and strength.

The term "detachment" refers to the loss of paper particles from the paper surface due to abrasion of the surface. Detachment tends to increase when conventional smoothing techniques, such as the use of chemical debonders, are used in the final wet section of a paper machine. In general, detachment is an unwanted property for personal care paper products. For example, many consumers react negatively to paper that exhibits a high level of detachment. Therefore, it is desired to provide a paper product that exhibits a minimum amount of release.

The term "softening agent" refers to chemical additives that can be incorporated into paper products to provide improved softness and tactile sensation. These chemical additives can also act to reduce paper stiffness and paper strength, and can only act to improve the surface characteristics of the tissue, such as by reducing the coefficient of friction between the paper surface and a person's hand. .

The term "water" refers to water or a solution containing water and other desired treatment additives in the paper making process.

These terms can be defined with additional language in the remaining parts of the specification.

DETAILED DESCRIPTION The present invention is concerned with a paper product, such as a paper product for care personal, and its properties. Generally noted, the present invention is directed to a paper product that, among other things, exhibits an improved level of softness and which minimizes peeling. In particular, the paper product includes fibers that are previously treated with a softening agent wherein the softening agent has been cured in the fibers, and wherein the fibers are then diluted and incorporated into the fiber jet of a paper machine .

Paper products for personal care can generally be formed in accordance with the present invention from at least one fibrous tissue. For example, in one aspect, the paper product may contain a single-layer fibrous fabric, formed from a mixture of pre-treated and untreated fibers. In another aspect, the paper product may contain a multilayer (e.g., laminated) fibrous fabric wherein at least one layer comprises at least pretreated fibers, and at least one layer comprises at least untreated fibers. In addition, the paper product itself can be constructed from a single fibrous tissue or from multiple fibrous tissues. In a particular aspect, at least one fibrous tissue in the paper product comprises fibers of previous treatment in accordance with the present invention.

In general, the basis weight of a fibrous fabric of the present invention is less than about 200 grams per square meter (gsm), such as between about 5 and about 120 grams per square meter or between about 10 grams per square meter (gsm). and around 70 grams per square meter. Fibers which are suitable for the invention include cellulose fibers such as hardwood fibers, softwood fibers, recycled fibers, and the like, as well as synthetic fibers. Such fibers can be formed by a variety of pulping processes, including kraft, sulfite, mechanical, thermomechanical, and chemo-thermomechanical pulping processes, and the like. In one example, the paper product includes a fibrous tissue having at least one layer formed mainly of kraft hardwood fibers of previous treatment.

Hardwood fibers such as eucalyptus, maple, birch, and poplar typically have an average fiber length of about 0.5 millimeters to about 1.5 millimeters and exhibit relatively large diameters (as compared to softwood fibers). As such, hardwood fibers may be more useful for improving the softness of a fibrous fabric than soft wood fibers. For the therefore, it may be desirable to provide at least one outer surface of a paper product that substantially comprises hardwood fibers. However, when conventional methods are used to improve softness, such as through the addition of a chemical debonderant in the wet final section of a paper machine, fibrous fabrics containing hardwood fibers tend to result in substantially more high levels of detachment.

In contrast, soft wood fibers such as soft wood from the north, southern softwood, redwood, cedar, hemlock, pine, and spruce typically have an average fiber length of about 1.5 millimeters to about 3 millimeters, with relatively small diameters (compared to hardwood). As such, soft wood fibers may be more useful for improving the strength of fibrous tissue than hardwood fibers. However, soft wood fibers substantially reduce the softness of a fibrous tissue. In addition, soft wood fibers can also result in increased release levels when conventional methods are used to improve softness. Therefore, softwood fibers are typically mixed with hardwood fibers, or they can used as an inner layer in the multilayer fibrous tissue.

If desired, secondary fibers obtained from recycled materials can also be used in a paper product of the invention. Such secondary fibers can be obtained from sources including old newspaper, reclaimed paperboard, envelopes, and mixed office waste. Additionally, other natural fibers can be used in the present invention, such as abaca, sabai grass, milkweed, pineapple leaf, and the like. In addition, in some instances, synthetic fibers can also be used, such as rayon fibers, ethylene vinyl alcohol copolymer fibers, polyolefin fibers, polyesters, and the like.

Suitable cellulose fibers of the present invention may include, for example, ARACRUZ ECF, a kraft pulp of eucalyptus hardwood, available from Aracruz, a business with offices located in Rio de Janeiro, Brazil; LONGLAC-19, a softwood pulp from the north available from Neenah Paper Inc., a business with offices located in Alpharetta, Georgia, United States of America; NB 416, a kraft pulp of bleached south softwood, available from Weyerhaeuser Co., a business that has offices located in Federal Way, Washington, United States of America; CR 54, a softwood kraft pulp from the bleached south, available from Bowater, Inc., a business with offices located in Greenville, South Carolina, United States of America; SULPHATATE HJ, a chemically modified hardwood pulp, available from Rayonier, Inc., a business located in Jessup, Georgia, United States of America; NF 405, a chemically treated bleached south softwood kraft pulp, available from Weyerhaeuser Co .; and CR-1654, a blend of hard wood kraft pulp and bleached south softwood, available from Bowater, Inc.

As referred to above, a paper product of the present invention can be formed of one or more fibrous fabrics, each of which can be simply placed or placed in multiple layers. For example, in one aspect, the paper product may comprise a single-ply paper fabric that is formed from a blend of fibers. For example, in some instances, soft wood and eucalyptus fibers can be mixed homogeneously to form a paper fabric placed in a single layer. In another aspect, the paper product may contain a tissue of paper placed in multiple layers being formed of a stratified pulp supplied having several main layers. In a particular aspect, the fibrous fabric may comprise three layers wherein at least one of the outer layers includes eucalyptus fibers of previous treatment, while at least the inner layer includes kraft fibers of soft northern untreated wood. In another aspect, the fibrous fabric may comprise two layers wherein one layer comprises hardwood kraft fibers from previous treatment, while the remaining outer layer comprises a mixture of untreated soft wood kraft fibers and untreated synthetic fibers. . In yet another aspect, the fibrous fabric may comprise three layers wherein at least one of the outer layers includes a mixture of hardwood fibers from previous treatment and untreated softwood fibers, while the inner layer comprises untreated recycled fibers. . It should be understood that a multilayer paper fabric can include any number of layers and can be made of various types of fibers.

In accordance with the present invention, various properties of a paper product as described above can be optimized. For example, softness, detachment level, strength (for example, tensile index), volume and the like, are some examples of properties that can be optimized in accordance with the present invention. However, it should be understood that not all the properties mentioned above need to be optimized in each instance. For example, in certain applications, it may be desired to form a paper product having optimized softness regardless of strength.

For purposes of the invention, the process of the pretreatment fibers with a suitable softening agent can first be achieved by adding a softening agent to the slurry or a fiber fabric, then allowing the combination to dry by at least about 80% consistency in such a way that the softening agent cures on the fibers, and then dilute the fibers with water, the re-milking of the fibers, and incorporate the fibers of previous treatment in the fiber jet of a papermaking process. The result is a paper product that exhibits an increased level of softness while minimizing the level of detachment. Without wishing to be bound by a particular theory, it is believed that the fibers of previous treatment with a softening agent according to the invention, result in the fibers having high resistance areas while decreases the total area bound between the fibers. More particularly it is believed that the total area bound together is diminished due to the inability of the previous treatment fibers to conform to the neighboring fibers (eg, less flexibility), thus creating more voids between the fibers during the papermaking process .

Suitable softening agents should have the ability to cure on the fibers, and should allow the fibers to re-leach substantially without minor defects. In some aspects, the softening agent can decrease the contact angle of the fiber and / or prevent the fiber from swelling through mechanisms such as crosslinking. In other aspects, the softening agent can decrease the total bound potential of the fibers without decreasing the tension surface of the fiber of the fiber-water suspension. In yet other aspects, the softening agent can decrease the strength of a fibrous fabric formed of pretreated fibers by at least about 30%, such as by at least about 50%, as compared to a similar fabric consisting of fibers without treating. In yet other aspects, fibrous tissues comprising fibers of previous treatment may exhibit a Water Retention Value of about 0.9 grams per gram or less.

Without being bound by a particular theory, it is believed that suitable softening agents used for the pretreated fibers according to the present invention result in fibers that are more compliant when wet. This, in turn, can prevent the total binding of such fibers to neighboring fibers in a fiber-water suspension, and therefore increases the softness of a resulting paper product. Additionally, the highest volume can be obtained in wet press fabrics because such pre-treated fibers can withstand the compression of a pressure roller on a paper machine. Furthermore, it is believed that the pretreatment fibers tend not to disengage through the reduction of surface tension, therefore the non-retained resin may tend to have no adverse effect on the other fibers, such as those used with the purpose of increasing the resistance.

Suitable softening agents include wet strength resins, size sorting agents, latex emulsions, cross-linking agents, and thermoplastics, as well as other additives. In general, Wet strength resins are typically used to impart mechanical strength to a paper product under wet conditions without adversely affecting the absorbency properties. However, as used in accordance with the present invention, the wet strength resin can result in a personal care paper product that exhibits improved softness while minimizing peeling. Suitable wet strength resins can be temporary or permanent, and can be cationic, anionic, or non-ionic.

Examples of suitable temporary wet strength resins include, but not limited to, cationic glyoxylated polyacrylamides such as those under the brand name of PAREZ 631 NC and PAREZ 725, available from Cytec Industries Inc., a business with offices located in West Paterson, New Jersey, United States of America and HERCOBOND 1366, available from Hercules Inc., a business with offices located in Wilmington, Delaware, United States of America. Other similar resins are described in U.S. Patent No. 3,556,932 issued to Williams et al., Here incorporated by reference in a manner consistent with this. description. Still other suitable temporary wet strength resins include dialdehyde starches, such as those under the brand name of COBOND 1000, available from National Starch & Chemical Company, a business with offices located in Bridgewater, New Jersey, United States of America, as well as those described in the patents of the United States of America numbers 6,224,714 granted to Schroeder and others; 6,274,667 issued to Shannon and others; 6,287,418 awarded to Schroeder and others; 6,365,667 granted to Shannon and others; 4,675,394 granted to Solares and others; and Japanese Patent Kokai Tokyo Koho JP 03,185,197, all of which are hereby incorporated by reference in a manner consistent with the present disclosure. Still other suitable temporary wet strength resins include, but are not limited to, dialdehyde starch, polyethylene imine, mannogalactam gum, glyoxal, and mangalactan dialdehyde. Other suitable temporary wet strength agents are described in U.S. Patent Nos. 3,556,932 issued to Coscia et al .; 5,466,337 issued to Darlington and others; 3,556,933 awarded to Williams and others; 4,605,702 granted to Guerro and others; 4,603,176 granted to Bjorkquist and others; 5,935,383 issued to Sun and others; and 6,017,417 granted to Wendt and others, all of which are here incorporated by reference in a manner consistent with the present disclosure.

Examples of suitable permanent wet strength resins include, but are not limited to, cationic polymeric or oligomeric resins, as well as those described in U.S. Patent Nos. 2,345,543 issued to Wohnsiedler et al .; 2,926,116 awarded to Keim; and 2,926,154 granted to Keim. Other suitable permanent wet strength resins include polyamine-epichlorohydrin resins, polyamide epichlorohydrin or polyamide-amine epichlorohydrin, which are collectively called polyamide epichlorohydrin (PAE) resins. These materials have been described in U.S. Patent Nos. 3,700,623 issued to Keim; 3,772,076 awarded to Keim; 3,855,158 issued to Petrovich and others; 3,899,388 issued to Petrovich and others; 4,129,528 issued to Petrovich and others; 4,147,586 issued to Petrovich and others; and 4,222,921 issued to Van Eenam, all of which are hereby incorporated by reference in a manner that is consistent with this description. Still other suitable permanent wet strength resins include polietienimine resins and aminoplast resins obtained by the reaction of formaldehyde with melamine or urea. In one example of the present invention KYMENE 6500, a polyamide-polyamine-epichlorohydrin commercially available from Hercules Inc., is used as the softening agent. Other commercially available resins include KYMENE 557H and KYMENE 557LX, also from Hercules, Inc. In some aspects, it is advantageous to use both permanent and temporary wet strength resins for the pretreated fiber.

As mentioned above, sorting agents by size can also be used as the softening agent. In general, size sorting agents are typically used in non-absorbent paper products, such as thin paper, to control over-penetration of the coating and ink formulas, reduced bleed for improved print quality, and improved opacity . However, when used in accordance with the present invention, sizing agents can result in a personal care paper product that exhibits improved softness while minimizing stripping. Suitable size classification agents can be natural or synthetic, and can be cationic, anionic or non-ionic. Appropriate classification agents by Natural sizes include, but are not limited to, modified and unmodified natural starches and rosins such as reserve polysaccharides found in plants (e.g., corn, wheat, potato, and the like) that may have linear (amylase) and / or branched (amylopectin) polymers of alpha-D-glucopyranosyl units. Suitable synthetic size sorting agents include, but are not limited to, synthetic copolymers such as polyvinyl alcohol and styrene, as well as other sizes of cellulose reagent including succinic alkene anhydride and dimer alkyl ketene. In one example of the invention, the size sorting agent HERCON 70, a dimer alkyl ketene is commercially available from Hercules Inc., is used as the softening agent.

As mentioned above, latex emulsions can also be used as the softening agent. In general, latex emulsions are typically used in coatings for fine paper, newsprint and coated paperboard used in packaging, such as for improved printing performance. However, when used in accordance with the present invention, latex emulsions can result in a personal care paper product that exhibits Improved softness while minimizing detachment. For the purposes of the present invention, latex emulsions can be used per se, or in conjunction with another polymer to form a latex emulsion complex. Appropriate latex emulsions include AIRFLEX 124, AIRFLEX 426, and AIRFLEX EN1165, all available from Air Products, a business with offices in Allentown, Pennsylvania, United States of America, and RESYN 225A, available from National Starch, a business with offices in Chicago, Illinois, United States of America. In one example of the present invention, a complex of a latex emulsion containing an emulsion of anionic butadiene styrene latex at a solids content of about 50% by weight under the brand name of LATRIX 6300, available from Nalco Company, a business with offices in Naperville, Illinois, United States of America, combined with a quaternary amine imidazoline softener at a solids content of about 80% by weight under the brand name of PROSOFT TQ-1003, available from Hercules, Inc. , it is used as the softening agent.

As mentioned above, cross-linking agents can also be used as the softening agent. In general, bonding agents in the form Cross-media are typically used to impart high strength in paper products that can be subjected to rigorous wet conditions, such as filter paper. However, when used in accordance with the present invention, cross-linking agents can result in a personal care paper product that exhibits improved softness while minimizing peeling. Suitable crosslinking agents include, but are not limited to, styrene-butadiene copolymers, polyvinyl acetate copolymers, acrylic vinyl acetate copolymers, ethylene-vinyl chloride copolymers, acrylic polymers, nitrile polymers, dispersed polyolefins, diols, polyols , diamines, polyamines, dicarboxylic acids, polycarboxylic acids, dialdehyde, polyaldehydes, butanediol, diethylene triamine, citric acid, glutaric dialdehyde, and diglycidyl ethylene glycol ether, tetravalent or trivalent metal ions, and combinations thereof.

The amount of softening agent added to the pretreated fibers according to the present invention will vary depending on the softening agent chosen. For example, in one aspect, a wet strength resin such as the KYMENE 6500 can be used in a quantity in the range from about 0.1 to about 10 dry kilograms / dry metric-tonne kiln (kilograms / ODMT) of fiber, such as about 1 to about 2 dry kilograms / dry metric-tonne kiln (kilograms / ODMT) of fiber. Alternatively, the KYMENE 6500 itself can be used in a pretreatment amount resulting in about 0.01 to about 5 dry kilograms / dry metric-tonne kiln (kilograms / ODMT) of fiber, such as from about 0.2 to about 1 dry kilograms / metric-ton dry kiln (kilograms / ODMT) of KYMENE 6500 on the fibers treated in the finished product. In another aspect, a size sorting agent such as HERCON 70 can be used in an amount in the range from about 1 to 10 dry kilograms / dry metric ton-tonne (kilograms / ODMT) fiber. In yet another aspect, a latex emulsion complex can be used in an amount in the range from about 1 to about 10 dry kilograms / dry metric-tonne kiln (kilograms / ODMT) of fiber. In yet another aspect, a cross-linked bonding agent may be used in an amount in the range from about 0.1 to about 10 dry kilograms / dry metric-tonne kiln (kilograms / ODMT) of dry fiber. Additionally, combinations of these agents are considered within the scope of this invention.

Numerous methods can be used for the fibers of previous treatment with a softening agent according to the present invention. Such methods should include the ability of the softening agent to be cured in the fibers, such as by drying, and should allow the fibers to be diluted with water and re-wetted substantially without minor defects. For example, in one aspect, the softening agent may be added to a dry liner pulp during the dry liner manufacturing process either in the dry end supply or in the formed sheet as before the dryer section. In another aspect, the softening agent may be added in a side-jet process as part of a paper making system where the pretreated fibers are allowed to dry and then re-milled and incorporated into the fiber system for making paper.

An exemplary process for the fibers of previous treatment with a softening agent according to the present invention is described below. With reference to Figure 1, the dry liner pulp manufacturing equipment 20 is illustrated in which a softening agent can be applied to the pulp fibers in accordance with one aspect of the present invention. invention. A fiber slurry 10 is prepared and then transferred through suitable conduits (not shown) to the main box 28 where the slurry of the fiber 10 is injected or deposited in the section of the fourdrinier 30 thereby forming a wet fibrous tissue. The wet fibrous tissue 32 can be subjected to mechanical pressure to remove the water from the process. It is understood that the process water may contain process chemicals used in the treatment of the fiber slurry 10 prior to a tissue forming step.

In the illustrated example, the section of the fourdrinier 30 precedes a press section 44, even when alternative dewatering devices such as a pressure point thickener, or the like can be used. The fiber slurry 10 is deposited on a foraminous web 46 in such a way that the filter of the fourdrinier section 48 is removed from the moist fibrous tissue 32. The filter of the fourdrinier section 48 comprises a part of a process water. The press section 44 or other dewatering device known in the art suitably increases the fiber consistency of the wet fibrous fabric 32 to about 30% by weight or greater, such as about 40% by weight or greater, hence creating a drained tissue 33. The Water from the process removed as the filter of the fourdrinier section 48 during the tissue formation step can be used as dissolution water for the dissolution stages in the processing of the pulp or can be discarded.

The dewatered fibrous fabric 33 may further be dewatered in further press sections or other dewatering devices known in the art. Adequately drained fibrous tissue 33 can be transferred to a drying section 34 where evaporator drying is performed on the dewatered fibrous fabric 33 at a consistency of about 80% by weight or greater, thereby forming a dried fibrous tissue (e.g. dry) 36. The dry liner 36 is then rolled onto a reel 37 or cut, or slit into sheets, and left to cure sufficiently before being fed to a paper machine.

The softening agent 24 can be added or applied to the dewatered fibrous fabric 33 or the dry liner 36 at a variety of addition points 35a, 35b, 35c, and 35d as shown in Figure 1. It is understood that while four addition points 35a, 35b, 35c, and 35d are shown in Figure 1, the application of the softening agent 24 may occur at any point between the initial dewatering point of the wet fibrous fabric 32 to the dry liner point 36 which is wound on the reel 37 or packed to be transported to the paper machines. The addition point 35a shows the addition of the softening agent 24 within the press section 44. The addition point 35b shows the addition of the softening agent 24 between the press section 44 and the drying section 34. The addition point 35c shows the addition of the softening agent in the drying section 34. The addition point 35d shows the addition of the softening agent 24 between the drying section 34 and the reel 37.

Once the softening agent has sufficiently cured in the fibers, the dry liner 36 can be diluted with water and re-dressed to form a fiber slurry after softening agent treatment. The pretreatment fiber slurry can then be incorporated into the fiber jet of a paper machine and processed to form a finished product.

A paper product made in accordance with the present invention can generally be formed in accordance with a variety of papermaking processes, known in the art. art. In fact, any process capable of making a paper web can be used in the present invention. For example, a papermaking process of the present invention can utilize wet pressure, creping, continuous air drying, creping continuously dried by air, creping without drying continuously in air, a single re-creping, and a double crepe. Also, calendering, engraving, as well as other steps in paper tissue processing can also be used. By way of illustration, various suitable processes for making paper are described in U.S. Patent Nos. 5,667,636 issued to Engel et al .; 5,607,551 granted to Farrington Jr. and others; 5,672,248 issued to Wendt et al .; and 5,494,554 issued to Edwards and others, all of which are incorporated herein by reference in a manner that is consistent with the present disclosure.

An exemplary papermaking process that can be used for the present invention is described below. In general, one or more fiber supplies are provided. For example, in one aspect, two fiber supplies can be used. Even when other fibers can be used, at least one fiber supply must comprise fibers of previous treatment. Also, by way of example, a second supply fiber can be used that contains soft wood fibers from previous treatment or untreated. In yet other aspects, by way of example, the second fiber supply or the third fiber supply may contain untreated or untreated fibers of hardwood, softwood, recycled, synthetic fibers, or combinations thereof.

The above exemplary fiber feedstocks can then be supplied to separate pulping apparatuses that disperse the fibers into individual fibers. The pulping apparatus can run continuously or in a batch format to supply fibers to the paper making machine. Once the fibers are dispersed, the supplies can then, in some embodiments, be pumped into a pour box and diluted to about 3% to about 4% by weight consistency. For example, in one aspect, a fiber supply containing pretreatment fibers can be transferred to a pour box. Then, the fiber supply can be transferred directly to a clean stock drawer, where it is diluted to a consistency of about 2% to about 3% by weight. If desired, additional chemical additives can also be added to the pour box and / or to the clean drawer of stock for improve various properties of the finished product. The supplies can also be diluted, if desired, to about 0.1% by weight consistency in the ventilation pump before entering the main box of a paper machine.

With reference to Figure 2, an exemplary fibrous tissue forming process (eg, the paper making machine) is described. In this example, a tissue 64 is formed by the supply of a fiber slurry 42 comprising pretreated fibers in a two-layer main layer 50. The main box 50 deposits the fiber slurry 49 between a forming fabric 52 and a conventional wet pressure paper felt (or carrier) 56 that is at least partially wrapped around a forming roll 54 and a press roll 58 to create a tissue 64. The tissue 64 is then tissue transferred from the papermaking felt 56 to the Yankee dryer 60 upon application of the vacuum press roll 58. An adhesive blend is optionally sprayed using a spray arm 59 onto the surface of the Yankee dryer 60 just after the application of the tissue 64 on the Yankee dryer 60 from the press roll 58. In some aspects, certain additives can be applied to the tissue of paper as the fabric passes through the dryer 60. A heated hood of natural gas (not shown) can partially surround the Yankee dryer 60, assisting in the drying of tissue 64. The tissue of tissue 64 can then be removed from the Yankee dryer by a creping doctor blade 62.

The fibrous web 64 can optionally be calendered, and then rolled onto a hard roller. The substrate can then be converted using various means known in the art to produce a paper product, such as a personal care paper product, which exhibits improved softness and minimizes peeling due to retention of the softening agent by the fibers of the paper. pulp of previous treatment.

Although the exemplary embodiment described above relates to a multilayer paper fabric having two layers, it should be understood that the paper fabric may contain any number of layers greater than or equal to one. For example, Figure 3 illustrates a particular aspect in which a paper machine comprises a 3-layer main box. As shown, an endless traveling fabric 76, suitably supported and driven by rollers 78 and 80, receives the paper in layers making the existence of exit from the main box 70. Once retained on the fabric 76, the fiber suspension passes water through the fabric as shown by the arrows 82. In one aspect, at least one of the outer layers 72, 74 may contain fibers of previous treatment and at least the inner layer 73 may contain fibers for improving the strength. The removal of the water can then be achieved as described above.

In addition, it should also be understood that layers of multilayer paper tissue may also contain more than one type of fiber. For example, in some aspects, one of the layers may contain a blend of previously treated hardwood fibers and untreated hardwood fibers, a blend of previously treated hardwood fibers and untreated softwood fibers, a mixture of untreated hardwood fibers and softwood fibers of previous treatment, a mixture of hardwood fibers of previous treatment and recycled fibers, a mixture of hardwood fibers of previous treatment and synthetic fibers, and the like.

It should be understood that a paper product of the present invention may comprise a single or multiple fibrous tissues. At least one of these fabrics is formed in accordance with the present invention. For example, in one aspect, a two-layer paper product can be formed. The first and second layers, for example, can be a multilayer paper fabric formed in accordance with the present invention. The configuration of the strata can also vary. For example, in one embodiment, a stratum can be placed in such a way that one layer comprises hardwood fibers from previous treatment that can define a first outer surface of the paper product to provide a smooth feel with minimized release to consumers. If desired, another layer can also be placed in such a way that one layer comprises fibers of hardwood of previous treatment which can define a second outer surface of the paper product.

The strata can be configured in a similar way when more than two strata are used. For example, in some embodiments, when a three-layer paper product is formed, the fibrous fabrics comprise pre-treatment fibers that can be placed to define the first and second outer surfaces of the paper product to provide a smooth feel with minimized detachment to consumers. Additionally, a third fibrous web comprising untreated softwood fibers can be placed to define an interior layer to provide improved strength of the paper product to consumers. However, it should also be understood that any other stratum configuration can be used in the present invention.

The present invention can be better understood with reference to the following examples.

EXAMPLES Pulp leaves Twenty-four grams of kiln dried fiber from several dry liner samples were used to prepare the pulp sheets each having a basis weight of approximately 460 grams per square meter. The pulp sheets were prepared by diluting the fiber with water in a BRITISH PULP DISINTEGRATOR pulp disintegrator (commercially available from Lorentzen &Wettre AB, a business with offices located in Atlanta, Georgia, United States of America).

America) at a consistency of 1.2% by weight.

Each sample was allowed to rinse in the blaster for a total of 5 minutes. After 2.5 minutes, a particular amount of desired softening agent was introduced into the water-fiber mixture and pulp was made in the disintegrator for 5 seconds before stopping and restarting the rinse period. After the rinsing period was completed, the sample was pulped in the disintegrator for 5 minutes at room temperature (e.g., around 25 degrees centigrade). A control sample was also made using the same procedure, but eliminating the step of adding the softening agent.

An appropriate amount of the fiber slurry required to make a sheet of 460 grams per square meter was measured in the graduated cylinder. The slurry was then emptied from the graduated cylinder into a 9 inch by 9 inch VALLEY hand sheet mold, commercially available from Voith Inc., a business with offices located in Appleton, Wisconsin, United States of America, which was previously filled at the appropriate level with water.

After emptying the slurry into the mold, the mold was then completely filled with water, including water used to rinse the graduated cylinder. The slurry was then gently stirred with a standard perforated mixing plate that was inserted into the slurry and moved up and down seven times, then removed. A valve was then opened to allow the fiber-water slurry to drain from the mold through a 90x90 mesh stainless steel wire cloth with a 14x14 mesh backing wire at the bottom of the mold retaining the fibers to form a fibrous tissue. The fabric was left to drain using the vacuum formed by the water fall of 31.5 inches.

A secant leaf of 360 grams of dependence per square meter (commercially available from Curtis Fine Papers, a business with offices located in Guardbridge, Scotland) was then placed on the fabric with the soft side of the blotter contacting the fabric. The tissue was then laid down from the mold wire using a 10-kilogram roller and passing over the leaves several times. The upper blotting sheet and the fibrous tissue were lifted from the grid. The drying sheet was then placed with the fibrous tissue facing up and was placed on two dry leaves of secant. Two additional dry blotter sheets were then placed on the fibrous tissue for a total of five drying sheets.

The stack of drying leaves, including the fibrous tissue, was placed in a VALLEY hydraulic press. (commercially available from Voith, Inc.) and pressed for one minute at a pressure of 100 pounds per square inch. The pressed fabric was then removed from the drying and drying sheets, the wire from the top side, for 2 minutes at absolute drying using a VALLEY STEAM HOTPLATE steam plate (commercially available from Voith, Inc.) heated with saturated steam to a pressure of 2 pounds per square inch and a heavy standard canvas cover that has a weight tube (4.75 pounds) on one end to keep the tension constant.

Hand Sheets Twenty-four grams of oven dried fiber from several pulp sheet samples described above were used to prepare the samples of hand sheet strips each having a basis weight of approximately 60 grams per square meter. The twenty-four gram pulp sheet sample was placed in a BRITISH PULP DISINTEGRATOR pulp disintegrator (commercially available from Lorentzen &Wettre AB, a business with offices located in Atlanta, Georgia, United States of America) and was diluted with water to a consistency of 1.2% by weight. The pulp fiber sample was again allowed to rinse for 5 minutes in the disintegrator, and then it was re-layered in the disintegrator for 5 minutes at room temperature (eg, around 25 degrees centigrade).

An appropriate amount of the fiber slurry required to make a sheet of 60 grams per square meter was measured in the graduated cylinder. The slurry was then emptied from the graduated cylinder into a 9 inch by 9 inch VALLEY hand sheet mold, (described above), which was previously filled to the appropriate level with water.

After emptying the slurry into the mold, the mold was then completely filled with water, including water used to rinse the graduated cylinder. The slurry was then gently stirred with a standard perforated mixing plate that was inserted into the slurry and moved up and down seven times, then removed. A valve was then opened to allow the fiber-water slurry to drain from the mold through a 90x90 mesh stainless steel wire cloth with a 14x14 mesh backing wire at the bottom of the mold retaining the fibers to form a fibrous tissue. The fabric was left to drain using the vacuum formed by the water fall of 31.5 inches.

A secant leaf of 360 grams of dependence per square meter (commercially available from Curtis Fine Papers, a business with offices located in Guardbridge, Scotland) was then placed on the fabric with the soft side of the blotter contacting the fabric. The tissue was then laid down from the mold wire using a 10-kilogram roller and passing over the leaves several times. The upper blotting sheet and the fibrous tissue were lifted from the grid. The blotting sheet was then placed with the fibrous tissue facing up and placed on two dry blotting sheets. Two additional dry blotter sheets were then placed on the fibrous tissue for a total of five drying sheets.

The stack of drying leaves, including the fibrous tissue, was placed in a VALLEY hydraulic press. (commercially available from Voith, Inc.) and pressed for one minute at a pressure of 100 pounds per square inch. The pressed fabric was then removed from the drying and drying sheets, the wire from the top side, for 2 minutes at absolute drying using a VALLEY STEAM HOTPLATE steam plate (commercially available from Voith, Inc.) heated with saturated steam to a pressure of 2 pounds per square inch and a heavy standard canvas cover that has a weight tube (4.75 pounds) on one end to keep the tension constant. The resultant hand sheet was then conditioned in a controlled humidity room at 23 degrees Celsius and 50% relative humidity before preparation as a strip sample from the hand sheet to be tested.

EXAMPLE 1 ARACRUZ ECF in the form of a dry lining sheet of 1000 grams per square meter was used to create a first set of pulp sheets, which was used to create a set of hand sheets. The methods of the pulp sheet and the hand sheet described above for making the hand sheets were used. This first set of comparative hand sheets, hereinafter referred to as Control 1, represents a paper product without any type of chemical treatment to improve aesthetic properties, such as softness. The hand sheets were then tested by various properties in accordance with the test procedures outlined below.

EXAMPLE 2 ARACRUZ ECF was used to create a set of pulp leaves, which were then used to create a set of hand sheets. The pulp sheet and hand sheet methods described above for making the comparative hand sheets were again used, except that the PROSOFT TQ-1003 binder (commelly available from Hercules Inc.) was added in an amount equal to 0.075. % on a dry fiber basis during the rewet step of the pulp of the previous hand sheet process. This second set of comparative hand sheets, hereinafter referred to as Control 2, represents a paper product in which the binder is added to the uncured fiber, such as through the addition at the wet end of a paper machine . The hand sheets were then tested by several properties in accordance with the test procedures indicated below.

EXAMPLE 3 ARACRUZ ECF was used to create a set of pulp sheets that were used to create a set of hand sheets. The same procedure was used as in EXAMPLE 2 above, except that the addition of the PROSOFT TQ-1003 binder was in an amount of 0.15% on a dry fiber basis. This third set of comparative hand sheets, hereinafter referred to as Control 3, represents a paper product in which a binder is added to the uncured fiber, such as through the addition at the wet end of a paper machine . The hand sheets were then tested by various properties in accordance with the test procedures outlined below.

EXAMPLE 4 ARACRUZ ECF was used to create a set of pulp sheets representing the prior treatment fibers of the present invention. The fibers were treated according to the pulp sheet method described above using a polyamide-polyamine-epichlorohydrin (PAE) type resin under the brand name of KYMENE 6500 in an amount equal to 0.2% on a dry fiber basis. The fibers were then diluted and releaved to form hand sheets according to the hand sheet procedure described above. This first set of fibers of previous treatment, hereinafter referred to as Sample 1, represents the fibers that are previously treated with a softening agent in the form of a permanent wet strength resin, then cured, and then diluted with water, re-incorporated and incorporated in the fiber jet for a paper machine to improve the aesthetic properties such as softness while minimizing detachment. The hand sheets were then tested for various properties in accordance with the test procedures outlined below.

EXAMPLE 5 ARACRUZ ECF was used to create a set of hand sheets representing the pretreatment fibers of the present invention. The fibers were treated in accordance with the leaf procedure of pulp described above using KYMENE 6500 in an amount equal to 0.5% based on dry fiber. The fibers were then diluted and releaved to form hand sheets according to the hand sheet procedure described above. This first set of fibers of previous treatment, hereinafter referred to as Sample 2, represents the fibers that are previously treated with a softening agent in the form of a permanent wet strength resin, then cured, and then diluted with water, slick and incorporated into the fiber jet for a paper machine to improve aesthetic properties such as softness while minimizing detachment. The hand sheets were then tested for various properties in accordance with the test procedures outlined below.

EXAMPLE 6 ARACRUZ ECF was used to create a set of hand sheets representing the pretreatment fibers of the present invention, identical to Sample 1 above using the pulp sheet method described above. Additionally, ARACRUZ ECF was used to create a set of comparative pulp sheets identical to Control 1 above using the sheet pulp procedure described above. A 1: 1 mixture of treated and untreated dried fiber sheets were diluted with water to a 1.2% consistency and slurries, and then made into the standard hand sheets using the hand sheet procedure described above. The first set of pre-treated / untreated fiber pulp sheets, hereinafter referred to as Sample 3, represents the fibers that are pre-treated with a softening agent in the form of a permanent wet strength resin, then cured and then diluted with water and re-grinded and incorporated into the fiber jet of a paper machine to improve aesthetic properties such as softness while minimizing detachment. The hand sheets were then tested by various properties in accordance with the test procedures outlined below.

The resulting properties of the comparative examples of Control 1-3, as well as of the examples of the invention of Samples 1-3 are shown in Table 1 below.

Table 1. Properties of the Previous Pulp Treatment with polyamide-polya-ina-epichlorohydrin (PAE) resin • Note, the samples are identified as "Control #" represent comparative examples, while the samples identified as "Sample # represent examples of the invention.

The results in Table 1 show that the fibers in Samples 1 and 2 that were previously treated with the permanent wet strength resin polyamide-polyamine-epichlorohydrin have a substantial de-agglutinating effect compared to Control 1 resulting in a low tensile index for the samples of previous treatment, that is to increase the softness (for example, as the traction index decreases, the softness increases). In fact, the reduction of the tensile index for Samples 1 and 2 is significantly greater for the previous samples treatment with PROSOFT binder samples from control 2 and 3. In addition, it can be assumed that the fibers of previous treatment show a reduced detachment at the same tensile strengths in comparison to a traditional wet final softener such as the PROSOFT imidazoline debonding agent. This can be illustrated when comparing the properties between Control 2, which was prepared with 0.75% PROSOFT binder and Sample 3, which was prepared using the 1: 1 ratio of 0.2% polyamide-polyamine-epichlorohydrin resin ( PAE) of treated fiber and untreated fiber. Additionally, the pretreatment fiber in Sample 3 has higher caliper and lower detachment than Control 2 at approximately the same tensile index. In general, the increased size for each of the previous treatment samples equals an increase in volume for the resulting paper product.

EXAMPLE 7 ARACRUZ ECF was used to create a set of pulp sheets representing the prior treatment fibers of the present invention. The fibers were treated according to the procedure described above using HERCON 70 in an amount equal to 0.15% on the basis of dry fiber. The fibers were then diluted and re-milled to form hand sheets according to the hand sheet procedure described above. This set of pretreatment fibers, hereinafter referred to as Sample 4, represents the fibers that are previously treated with a softening agent in the form of a permanent wet strength resin, then cured, and then diluted with water, re-mixed and incorporated in the fiber jet for a paper machine to improve aesthetic properties such as softness while minimizing detachment. The hand sheets were then tested for various properties in accordance with the test procedures outlined below.

EXAMPLE 8 ARACRUZ ECF was used to create a set of pulp sheets representing the prior treatment fibers of the present invention. The fibers were treated according to the procedure described above using HERCON 70 in an amount equal to 0.50% based on dry fiber. The fibers were then diluted and re-milled to form hand sheets according to the hand sheet procedure described above. This pre-fiber set The treatment, hereinafter referred to as Sample 5, represents the fibers that are previously treated with a softening agent in the form of a permanent wet strength resin, then cured, and then diluted with water, re-milled and incorporated in the fiber jet. for a paper machine to improve aesthetic properties such as softness while minimizing detachment. The hand sheets were then tested for various properties in accordance with the test procedures outlined below.

The resulting properties for the comparative examples of Control 1-3 as well as for the examples of the invention of Samples 4-5 are shown in Table 2 below.

Table 2 Properties of the Anterior Pulp Treatment with the AKD size agent Note, the samples are identified as "Control #" represent comparative examples, while the samples identified as "Sample #" represent examples of the invention.

The results in Table 2 show that the fibers from previous treatment with a size-classifying agent resin of the type of alkyl diene has a substantial binder effect compared to control 1 resulting in a low tensile index for the previous treatment samples. , which is equivalent to an increase in softness (for example, as the tensile index decreases, the softness increases). Furthermore, it can be assumed that the fibers of previous treatment show a potential detachment at the same tensile strengths compared to a traditional wet final softener such as the PROSOFT imidazoline binder used in Control 2 and 3. Additionally, the increased size of the samples of previous treatment equals an increase in volume for the resulting paper product.

EXAMPLE 9 ARACRUZ ECF was used to create a set of pulp sheets representing the prior treatment fibers of the present invention. The fibers were treated according to the procedure described above using an anionic hydrophobic polymer emulsion complex and a Cationic surfactant in a mass ratio of 2: 1 in an amount equal to 0.3% based on dry fiber. The complex was prepared by mixing the LATRIX 6300 emulsion at a solids content of about 50% by weight with PROSOFT TQ-1003 at a solids content of about 80% by weight. The fibers were then diluted and releaved to form hand sheets according to the hand sheet procedure described above. This set of fibers of previous treatment, hereinafter referred to as Sample 6, represents the fibers that are previously treated with a softening agent in the form of a permanent wet strength resin, then cured, and then diluted with water, re-slurry and incorporated in the fiber jet for a paper machine to improve the aesthetic properties such as softness while minimizing detachment. The hand sheets were then tested for various properties in accordance with the test procedures outlined below.

EXAMPLE 10 ARACRUZ ECF was used to create a set of pulp sheets representing the prior treatment fibers of the present invention. The fibers were treated according to the procedure described above using a emulsion complex of anionic hydrophobic polymer and a cationic surfactant in a mass ratio of 2: 1 in a amount equal to 1.0% on the basis of dry fiber. The complex was prepared by mixing the LATRIX 6300 emulsion in a solids content to around 50% by weight with PROSOFT TQ-1003 at a solids content of around 80% by weight.

The fibers were then diluted and re-coated to form hand sheets in accordance with the sheet procedure hand described above. This pre-fiber set treatment, hereinafter referred to as Sample 7, represents the fibers that are previously treated with an agent softener in the form of a wet strength resin permanent, then cured, and then diluted with water, re-leased and incorporated into the fiber jet for a machine paper to improve aesthetic properties such as softness while minimizing detachment. The sheets of hand were then tested for various properties of in accordance with the test procedures indicated below.

The resulting properties for the comparative examples of Control 1-3 as well as for the examples of the invention of Samples 6-7 are shown in Table 3 below.

Table 3. Properties of the Previous Pulp Treatment with the Polymer complex Note, the samples are identified as "Control #" represent comparative examples, while the samples identified as "Sample #" represent examples of the invention.

The results in Table 3 show that the fibers from previous treatment with the complex formed from the emulsion of anionic hydrophobic polymer with a cationic surfactant in a ratio of 2: 1 have a substantial debitling effect compared to the untreated control, which equals increase of softness (for example, as the tensile index decreases, smoothness increases). In addition, it can be assumed that the fibers of previous treatment with the polymer complex exhibit lower detachment or lower tensile strengths compared to the controls of the PROSOFT binder. Additionally, the increased size of the pre-treatment samples equals an increase in volume for the resulting paper product.

EXAMPLE 11 90% of the ARACRUZ ECF eucalyptus / 10% northern softwood pulp leaf LL19 was produced on a pilot scale tissue machine at a speed of 18 feet per minute. The pulp sheet was dried at 85% solids with a basis weight of 160 grams per square meter. The pulp sheet was re-milled for 30 minutes at 120 degrees Fahrenheit (hereafter, the "Untreated Fibers") and used to make a comparative example as Control 4.

A fibrous fabric placed in layers having a basis weight of about 7.0 pounds per 2880 square feet of dried tissue was then produced on a pilot-scale tissue machine by using a 3-layer main box to form a sheet having two outer layers and one inner layer. The first outer layer comprising 66% ARACRUZ ECF and 34% of the untreated fibers above. The inner layer comprises 70% of LL-19 fibers and 30% of the untreated fibers above. A solution of 0.1% strength additive under the brand name of HERCOBOND 1366, available from Hercules Inc., was also added to the core layer to control the ultimate strength of the fibrous tissue in layers at a geometric average tension of 2.41 Nm / g. the diluted solution of HERCOBOND 1366 was added continuously through a pump to the tube of existence rather than to the main box. The remaining outer layer comprises 66% ARACRUZ ECF and 34% of the untreated fibers above. Additionally, a wet strength additive solution, under the brand name of KYMENE 6500, available from Hercules Inc., was added to all three layers in an amount of 2 dry kilograms per dry metric tonne of tissue to provide wet strength to the product. The KYMENE 6500 was added to the pulp storage tub and allowed to mix for 10 minutes before the pulp was transported to the main box.

The layered fibers were deposited from the main box on a forming fabric and vacuum dewatered. The tissue tissue was then transferred to a papermaking felt which brought the wet fabric to approximately 20% content from the formica fabric to a press roll which further presses water from the fabric to approximately a 45% content and transferred the tissue to a Yankee dryer. An adhesive mix was sprayed using a spray pump on the surface of the Yankee dryer just before the application of the tissue tissue by the press roller. The adhesive mixture contains about 40% by weight of polyvinyl alcohol, about 40% by weight of polyamide resin and about 20% by weight of quaternized polyamide amine, such as described in the United States of America patent number 5,730,839 issued to endt et al., Which is incorporated herein by reference in a manner that is consistent with the present disclosure. The rate of application of the adhesive blend was about 6 pounds of dry adhesive per metric ton of dried pulp fiber to the honour in the tissue tissue.

The sheet was dried in the Yankee dryer which was heated with a saturated pressure steam of 23 pounds per square inch. Additionally, a heated hood of natural gas partially surrounds the dryer. Yankee has an air supply at a temperature of about 600 degrees Fahrenheit to assist in the drying of the tissue tissue. The tissue tissue temperature after application of the creping doctor was around 225 degrees Fahrenheit, as measured by a hand-held infrared temperature gun. The sheet was creped out of the dryer using a steel blade with a 10 degree bevel. The knife was held in a chamber with an extension of% inch, which was pressed against the dryer with sufficient force to allow the tissue to be uniformly scraped from the dryer. The tissue was wound on a reel that moves 27% slower than the Yankee dryer. The speed of the tissue machine 16 inches wide was around 50 feet per minute.

Two rolls of creped tissue were then unrolled and folded together in a manner that allows both creped sides to be outside the two-layer structure. The folded structures were calendered at approximately 40 pounds per linear inch, mechanically crimped over the edges to hold the strata together, and slit over the edges to achieve a width of approximately 8. 5 inches to form a two-layer facial tissue product. The product was then tested for various properties in accordance with the test procedures outlined below. The results can be seen in Table 4.

EXAMPLE 12 A 90% ARACRUZ Eucalyptus ECF / 10% of a sheet of softwood pulp from the north LL-19 was produced on a pilot-scale tissue machine at a speed of 18 feet per minute. In this example, the fibers were pre-treated with KYMENE 6500 polyamide-polyamine-epichlorohydrin (PAE) resin controlled to achieve an added amount of 0.1% on a dry fiber basis. The treatment resin involves mixing the resin with the pulp fibers for 30 minutes of time to make the pulp at 120 degrees Fahrenheit before forming and drying the pulp sheet. The pulp sheet was dried at 85% solids with a basis weight of 160 grams per square meter. The pulp sheet was then re-milled for 30 minutes at 120 degrees Fahrenheit (hereinafter the "pre-treatment fibers") and used as a fiber source to produce Sample 8, a two-layer facial tissue product produced from the same way as Control 4 above, with the exception that the amounts of untreated fibers were replaced with previous treatment fibers made in this example. The product was then tested for various properties in accordance with the test procedures outlined below. The results can be seen in Table 4.

Table 4. Facial Tissue of Two Strata using a pulp of previous treatment of polyamide-polyamine-epichlorohydrin resin (PAE).

Note: the samples that were identified as "Control #" represent comparative examples, while the samples that are identified as "Sample #" represent examples of the invention.

The results in Table 4 show that a tissue product made from pre-treated fibers with the inclusion of 20% polyamide-polyamine-epichlorohydrin (PAE) resin in the supply has, at approximately the same tensile strength of geometric mean ( GMT), an increase in caliber with less detachment.

EXAMPLE 13 The samples were produced in a manner similar to Control 1-3 and samples 1-2 and 4-7 above. However, before the re-sanding step of the samples, the fibers were tested to determine the water retention values using the procedure described below. In the case of Control 2 and Control 3, PROSOFT chemistry was added during the pulp leaf procedure, instead of during the re-grinding step of the hand sheet procedure. The results are shown in Table 5. Additionally, these same samples were used to measure the Long Ripple Length index using the procedure described below. The values of the Curling index are also shown in Table 5.

Table 5. Water Retention Values of the Pulp Sheet Note: Samples that were identified as "Control #" represent comparative examples, while samples that are identified as "Sample #" represent examples of the invention.

The data in Table 5 suggest a potential mechanism that describes why the pretreatment pulp of the present invention creates a paper product that has increased softness while minimizing peeling. Without wishing to adhere to a particular theory, it seems that having less water retention, a mechanism of the de-agglutinating invention is created that differs from the use of typical chemical de-binders. For example, it is believed that fibers of previous treatment, which have less water in them, are less flexible and create a lower density of the fibrous mat in the wet forming process. It can be assumed that the fibrous mat of lower density decreases the contact of the fiber with the fiber, thus making the mat weaker. This contrasts with the chemical binder which is believed to adsorb the fibers and reduce the hydrogen bonding of the fibers through the coverage of the hydroxyl and carboxyl sites as well as reducing the surface tension that pulls the fibers together. Therefore, it is believed that the invention reduces fiber to fiber contact but allows strong bonds to form where contact is made, while traditional binder chemistries reduce the strength of all bonds through adsorption to cellulose.

PROOF PROCEDURES Stress test Unless otherwise specified, tensile strengths were measured according to the TAPPI T 494 om-88 test method for the tissue, modified in that the tension tester used a crosshead speed of 10 inches per minute. The samples were conditioned at 23 ° C +/- 1 ° C and 50% +/- 2% relative humidity for a minimum of four hours. The hand sheets were cut into one-inch-wide strips using a JDC 15M-10 precision sample cutter model, commercially available from Thwing-Albert Instruments, a business having offices located in Philadelphia, Pennsylvania, United States of America.

Each strip was then placed on the tension frame at a measurement length of 5 inches. The tensile frame used in these experiments was an ALLIANCE RT / 1 frame run with TEST ORKS 4 software, available from MTS Systems Corporation, a business having offices located in Cary, North Carolina, United States of America. Each strip was then subjected to a tension of 0.5 inches per minute and the resulting stress was recorded with an appropriate load cell.

The tension index (TI) is a measure of the normalized tensile strength for a basis weight of the tested tissue. The tensile strength as measured above can be converted to the stress index using the following formula: tension index = peak load (N) / [sample base weight (g / m2) x sample width (m)] where the peak load is expressed in Newtons (N), the sample base weight is expressed in grams per square meter (g / m2), the sample width is expressed in meters (m), and the tension index is expressed in newton meter per gram (Nm / g).

The geometric mean stress (GMT) was also calculated for the samples to provide an average resistance independent of the test direction. The geometric mean stress was calculated using the following formula: GMT = Square root (voltage value MD x voltage value CD) The tension test procedure for the control tissue samples 4 and sample 8 was slightly modified. These particular tissue samples were conditioned at 23 ° C +/- 1 ° C and 50% +/- 2% relative humidity for a minimum of 4 hours. The samples were cut into 3-inch-wide strips using a precision sample from the JDC 15M-10 cutter model. The two strips, to represent a product of two strata, were placed in the tension frame at a measuring length of 4 inches.

The tension framework used in this experiment was the ALLIANCE RT / l frame run with a TESTWORKS 4 software described above. Each strip was then subjected to a tension of 10 inches per minute and the resulting effort was Registered with an appropriate load cell. The tension index and the geometric mean stress were then calculated as described above.

Caliber test The term "caliber" as used herein refers to the thickness of a single tissue sheet. The gauge can be measured either as the thickness of a single tissue sheet or as the thickness of a stack of 10 sheets of tissue where each sheet inside the stack is placed on the same side up and dividing the measurement by ten . The size is expressed in microns or 0.001 inches. The gauge was measured according to the TAPPI T402 test methods "Standard packaging and test atmosphere for paper, cardboard, pulp sheets and related products" and T411 om-89"Thickness (gauge) of paper, cardboard and combined paperboard" optionally with note 3 for stacked tissue sheets. The micrometer used to perform the T 411 om-89 test was a volume micrometer model 49-72-00 (available from TMI Company, a business having offices located in Atyyville, New York, United States of America) or the equivalent having an anvil diameter of 4-1 / 16 inches (103.2 millimeters) and an anvil pressure of 220 grams / square inch (3.3 kilopascal).

Proof of Escaras The bedsores test determined the resistance or abrasion tendency of the fibers to be rubbed from the fabric when handled. More particularly, this test measures the resistance of the tissue material to the abrasive action when the material is subjected to a horizontally reciprocating surface erode. Each sample was measured by erosion of the tissue specimen through the following method.

All samples were conditioned at 23 ° C +/- 1 ° C and 50% +/- 2% relative humidity for a minimum of four hours. The eschar of each measured sheet was measured using a strip 3 inches wide by 8 inches long held by the heavy clamps allowing the mandrel to rotate slowly and roughly passing back and forth under the tissue strip by a number of predetermined cycles. This instrument was designed by Kimberly-Clark Corporation of Neenah, Wl. Weights to the nearest 0.0001 grams are recorded for each sample strip before and after the test to determine the amount of eschar measured in milligrams.

With reference to Figure 4, the abrasion spindle 94 contained a stainless steel rod 96, 0.5 inch in diameter with the abrasive part 84 having a pattern of 0.005 inch deep diamond extending 4.25 inches in length around the full circumference of the rod 96. The spindle 94 was mounted perpendicular to the face of the instrument so that the abrasive part 84 of the rod 96 extends outward from its distance complete from the face of the instrument 100. The guide pins 102, 104 with the magnetic clamps 86, 88 are located on each side of the spindle 94 on a mobile 86 and a fixed 88, spaced 4 inches apart and centered around the spindle 94. The movable clamp 86 and the guide pins 102 were allowed to slide freely in the vertical direction, providing the means to ensure a constant tension of the sample on the spindle surface 94.

Using a die press with a die cutter, the specimens 92 were cut into strips of 3 +/- 0.05 inches wide by 8 inches long with two holes (not shown) at each end of the sample 92 for the pins of the die. guide 102, 104 to adjust through. For tissue samples 92, the MD address corresponds to the longest dimension. Each test strip 92 was then weighed to the nearest 0.0001 grams. Each end of the sample 92 was slid over the guide pins 86 and 88 and the magnetic clamps 86 and 88 held the sheet 92 in place. The moving jaw 86 was then dropped providing a constant tension through the spindle 94.

The spindle 94 was then moved back and forth at an angle of approximately 15 ° from the vertical centerline centered on a reciprocal horizontal movement 90 against the test strip 92 for 40 cycles (each cycle is a one-way stroke and back) at a rate of 80 cycles per minute, removing loose fibers from the surface of the fabric. Additionally, spindle 94 rotated from right to left 98 (when viewed in front of the instrument) at a rate of approximately 5 revolutions per minute. The magnetic clamps 86 and 88 were then removed from the sample 92 and the sample 92 was slid out of the guide pins 102 and 104 and any loose fibers on the sample surface 92 were removed by blowing compressed air (approximately 5- 10 pounds per square inch) on test sample 92. Test sample 92 was then weighed to the nearest 0.0001 grams and weight loss was calculated. Ten test samples per tissue sample were tested and the average weight loss value in grams (or milligrams) was recorded.

Water retention value Each sample of dried pulp was disintegrated by dilution in deionized water to a consistency of 1.2% by weight in a British pulp disintegrator (described previously) . The pulp fiber sample was allowed to soak for 5 minutes before being pulped at 15,000 revolutions for 5 minutes at room temperature (for example around 25 ° C). A sheet of Whatman No. 1 filter paper (available from Whatman Inc., a business having offices located in Clifton, New Jersey, United States of America) used for a gravity filter of approximately 100 mL of the fiber suspension was supported on a 50 mesh wire mesh in a plastic centrifuge tube with a drainage hole on the bottom. Four samples were prepared in this manner and placed in centrifugal metal tubes with a space of approximately 3 millimeters to allow water to drain from the samples. The assembly was placed in a centrifuge where the samples were accelerated to achieve 900 gravities of centrifugal forces on the pulp specimens. The samples were spun at this rate for 30 minutes after which the samples were removed using a dissecting needle.

The filter papers were quickly separated from the drained filter samples and each sample was placed on a pre-weighed drying dish. Each wet sample was weighed, subtracting the weight of the dish, recorded as the wet fiber weight (Whipped). The sample was then dried in an oven at approximately 105 ° C for 12 hours and weighed again with the weighing plate. The weighing plate was subtracted and recorded as the dry fiber weight (Wseco). The water retention value (WRV) was calculated from the following equation: WRV = (Whúmedo - Wseco) / Wseco where Whúmedo and Wseco are expressed in grams (g), and WRV is expressed as grams water / gram fiber. curly index The "curl" or "curl index" of a fiber is the measurement of the shortening of the fraction of a fiber due to the twists, curls and / or bends in the fiber. For the purposes of this invention, a fiber ripple value is measured in terms of a two-dimensional plane determined by viewing the fiber in a two-dimensional plane. To determine the curl index of a fiber, the projected length of a fiber as the longest dimension of a two-dimensional rectangle encompassing the fiber (I) and the current length of the fiber (L) are both measured. An image analysis method can be used to measure "L" and "I". An adequate image analysis method is described in U.S. Patent No. 4,898,642 issued to Moore et al., Which is incorporated herein by reference in a way that is consistent with this description. The ripple value of a fiber can then be calculated from the following equation: curly index = (L / I) - 1 The wet rip value for the fibers was determined using the OPTEST product code of LDA 96 fiber quality analyzer, available from Op Test of Equipment Inc., a business having offices located in Hawkesbury, Ontario, Canada. The sample was placed in a 600 milliliter plastic sample container to be used in the fiber quality analyzer. The fiber sample in the vessel was diluted with tap water until the fiber concentration in the vessel was about 10 to about 25 fibers per second for evaluation by the fiber quantity analyzer. An empty plastic sample container was filled with tap water and placed in the fiber quality analyzer test chamber. The < Verification system > of the fiber quality analyzer was then pushed. If the plastic sample container filled with tap water was properly placed in the test chamber, the < OK > of the fiber quality analyzer. The fiber quality analyzer then carried out a self-test. If a warning was not displayed on the screen after the Self-test, the machine is ready to test the fiber sample.

The plastic sample container filled with tap water was removed from the test chamber and replaced with the fiber sample container. The button < Measurement > of the fiber quality analyzer was then pushed. The button < New measurement > of the fiber quality analyzer was then pushed. A fiber sample identification was then written into the fiber quality analyzer. The button was then pressed < OK > of the fiber quality analyzer. The button < Options > of the fiber quality analyzer was then pressed. The fiber account was then set to 3,000. The parameters for scaling a graph that is going to be printed out were set to automatic. The button < Previous > of the fiber quality analyzer was then pressed. The < Start > of the fiber quality analyzer was then pressed. If the fiber sample container was properly placed in the test chamber, the < OK > of the fiber quality analyzer.

The fiber quality analyzer then begins the test and displays the fibers that pass through the flow cell. The fiber quality analyzer also exhibited the frequency of fiber passing through the cell flow, which was around 10 to about 20 fibers per second. If the fiber frequency is outside this range, the < Stop > The fiber quality analyzer must be pressed and the fiber sample must be diluted or have more fibers added to bring the fiber frequency within the desired range. If the fiber frequency is sufficient, the fiber quality analyzer tests the fiber sample until it reaches a count of 3,000 fibers at which point the fiber quality analyzer automatically stops. The < Result > of the fiber quality analyzer was then pressed. The fiber quality analyzer calculated the wet ripple value of the fiber sample, which was printed by pressing the < Done > of the fiber quality analyzer.

It will be appreciated that the details of the foregoing examples, given for purposes of illustration, should not be considered as limiting the scope of this invention. Although only exemplary embodiments of this invention have been described in detail above, those skilled in the art will readily appreciate that many modifications are possible in the examples without departing materially from the novel teachings and advantages of this invention. For example, the features described in relation to an example may be incorporated in any other example of the invention.

Therefore, all modifications are intended to be included within the scope of this invention, which is defined in the following claims and all equivalents thereof. Furthermore, it is recognized that many embodiments can be conceived which do not achieve all the advantages of some embodiments particularly of the preferred embodiments, but the absence of a particular advantage should not be considered as necessarily meaning that such incorporation is beyond the scope of this invention. As several changes can be made in the above constructions, without departing from the scope of the invention, it is intended that all the material contained in the above description be interpreted as illustrative and not in a limiting sense.

Claims (20)

R E I V I N D I C A C I O N S

1. A paper product comprising at least one fibrous web which comprises pre-treated cellulosic fibers, wherein said previously treated cellulosic fibers have been cured with a softening agent prior to incorporation into said paper product.

2. The paper product as claimed in clause 1, characterized in that about 10% to about 50% of said cellulosic fibers pre-treated.

3. The paper product as claimed in clause 1, characterized in that at least one fibrous fabric comprises the cellulosic fibers previously treated having a water retention value below 0.9 g / g-

4. The paper product as claimed in clause 1, characterized in that at least one fibrous web has a tensile strength that is reduced by at least 50% compared to the same fibrous web comprising untreated cellulosic fibers.

5. The paper product as claimed in clause 1, characterized in that the softening agent is selected from the group consisting of wet reinforcing resins, sizing agents, latex emulsions, intercrossing agents and combinations thereof .

6. The paper product as claimed in clause 5, characterized in that the wet strength resin is selected from the group consisting of glyoxylated polyacrylamide, dialdehyde starch, containing aldehyde, polyamide-polyamine-epichlorohydrin, polyethylamine resins, aminoplast and combinations thereof.

7. The paper product as claimed in clause 5, characterized in that the sizing agent is selected from the group consisting of succinic alkenyl anhydride, alkyl ketene dimer, amylopectin starch and combinations thereof.

8. The paper product as claimed in clause 5, characterized in that the latex emulsion is a complex formed of an emulsion of butadiene styrene-anionic latex of hydrophobic polymer at a solids content of about 50% by weight and a quaternary amine imidazoline softener at a solids content of about 80% by weight.

9. The paper product as claimed in clause 5, characterized in that the intercrossing agent is chosen from the group consisting of styrene-butadiene copolymers, polyvinyl acetate copolymers, vinyl acetate acrylic copolymers, sodium chloride copolymers, vinyl-ethylene, acrylic polymers, nitrile polymers, dispersed polyolefins and combinations thereof.

10. The paper product as claimed in clause 1, characterized in that it also comprises an unglutinating agent.

11. The paper product as claimed in clause 1, characterized in that the cellulosic fibers previously treated are not uniformly distributed through said soft paper product.

12. The paper product as claimed in clause 1, characterized in that the previously treated cellulosic fibers are discretely distributed within said soft paper product.

13. The paper product as claimed in clause 1, characterized in that the fibers Cellulosics treated previously have a curl index of less than 0.2.

14. The paper product as claimed in clause 1, characterized in that the cellulosic fibers previously treated comprise essentially hardwood fibers.

15. The paper product as claimed in clause 14, characterized in that the hardwood fibers comprise eucalyptus fibers.

16. The paper product as claimed in clause 1, characterized in that said at least one fibrous fabric is a multilayer fibrous fabric having two outer layers, wherein at least one of said two outer layers comprises said fibers cellulose treated previously.

17. A method for making a paper product comprising: • provide a fiber solution comprising water and cellulosic fibers; • adding a softening agent to said cellulose fibers; • allowing said softening agent to cure with said cellulosic fibers to form previously treated fibers; • diluting said pretreatment fibers with water, - re-filling said previously treated fibers and water to form a solution of previously treated fiber; 15 • incorporating said previously treated fiber solution into a fiber stream of a paper making machine; • forming a fibrous web comprising said fibers previously treated on said paper making machine; Y • converting said fibrous tissue into a paper product 25

18. The method as claimed in clause 17, characterized in that it also comprises adding a debinding agent to said fiber stream.

19. The method as claimed in clause 17, characterized in that said paper product comprises about 10% to about 50% of said cellulosic fibers previously treated.

20. The method as claimed in clause 17, characterized in that said fibrous fabric further comprises synthetic fibers. SUMMARY A paper product includes fibers, such as cellulosic fibers, which are pretreated with a softening agent. The softening agent is added to a fiber solution and then allowed to cure on the fibers, typically by drying. The previously treated fibers are then diluted, put back into solution and incorporated into the fiber stream of a paper machine to form a fibrous tissue. The fibrous tissue can then be converted into a paper product, such as a personal care paper product, which exhibits improved softness with minimized eschar.