WO2019035022A1

WO2019035022A1 - Tissue paper articles and methods of making and using the same

Info

Publication number: WO2019035022A1
Application number: PCT/IB2018/056157
Authority: WO
Inventors: Joel J. Pawlak; Ryan Nicholas CHAN
Original assignee: Anavo Technologies LLC; North Carolina State University
Current assignee: Anavo Technologies LLC; North Carolina State University
Priority date: 2017-08-16
Filing date: 2018-08-16
Publication date: 2019-02-21
Anticipated expiration: 2020-02-16

Abstract

Tissue paper (e.g., non-woven) articles are described herein along with methods of making and using the same. In some embodiments, provided herein are tissue paper articles and/or methods of making the same that increase the strength of the tissue paper article and/or maintain or increase the softness of the tissue paper article.

Description

TISSUE PAPER ARTICLES AND METHODS OF MAKING AND USING THE

SAME

STATEMENT OF PRIORITY

This application claims the benefit, under 35 U.S.C. § 1 19(e), of U.S. Provisional

Application Serial No. 62/546,223, filed August 16, 2017, the entire contents of which is incorporated by reference herein.

FIELD

The present invention relates to tissue paper (e.g., non-woven) articles along with methods of making and using the same. In some embodiments, provided herein are tissue paper articles and/or methods of making the same that increase the strength of the tissue paper article and/or maintain or increase the softness of the tissue paper article. BACKGROUND

Paper based tissue, towels, napkins, facial tissue, and toilet tissue (collectively "tissue paper based hygiene products") make up about a 36 million ton annual market worldwide. In this market, the performance of the product is critical as in many cases these products are targeted at consumers. The softness, strength (dry and/or wet), and absorbency are all key factors in how a consumer evaluates the value of a product. Typically, to improve the strength of tissue paper based hygiene products, one of four different approaches is undertaken. First, the fiber used to create the sheet may be refined or beaten to increase fibrillation, and make the fiber more flexible in the wet state. This leads to consolidation of the sheet during the tissue making process. This increased consolidation (density) of the sheet has a negative impact on the softness of the sheet. Thus, this approach presents a softness/strength trade-off. The second approach is to increase the wet pressing of the sheet. If a tissue machine has a wet press, it is typically run at a relatively low pressure so as to provide some water removal and consolidation of the sheet, but not high enough to over consolidate the sheet. Over consolidation leads to improved strength, but decreased softness. The next approach to improving sheet strength is to increase the amount of softwood (long) fiber in the sheet. The problem with this is that softwood does not create a soft sheet due to its rather large fiber size and overall coarseness. Thus, once again, one gets additional strength while sacrificing softness. Lastly, one can add strength additives to the fiber furnish. This enhances the bonding between the fibers and makes the overall strength of the material greater. This also tends to bond surface fiber to the sheet, which in effect reduces the surface softness of the sheet. Thus, strength improvements are achieved, but with a sheet that has reduced softness.

The processes used to create tissue, toweling, and napkins are distinctly different and have distinctly different objectives when compared to regular paper grades. The objective in creating regular paper is to create a smooth and consolidated sheet of material that is rigid and has good stiffness qualities. In tissue, toweling, and napkin, the objective is to create a textured surface with minimal consolidation and maximum flexibility, While some processes are similar between paper and tissue making, tissue making includes different processes to create the desired characteristics. For example, tissue may be dried on a Yankee dryer. This is a very large (-150 tons) drum dryer to which the wet tissue sheet is adhered with chemical agents. After drying, the tissue sheet is scraped off using a creping doctor. This creping action imparts softness and flexibility to the sheet. Another drying system, which may be used in combination with the Yankee dryer or by itself to dry the tissue sheet, is a Through Air Dryer (TAD). In the TAD system, air is forced through the sheet to create a textured soft surface and bulky tissue sheet. These technologies may also be used for toweling and napkins as well.

In regard to tissue paper based hygiene products, consumers generally require a minimum strength and below this value the product is of little utility. For some grades (facial tissue and toilet tissue), the softness is of high importance. Consumers will generally pay a higher amount for softer and more absorbent products. Thus, producers compete by trying to make increasingly softer tissue while maintaining the minimal functional strength. This is classically known as the softness/strength tradeoff.

One means for increasing the strength and softness is to create novel structures in the tissue sheet. For example, through-air drying of the tissue sheets allows for the creation of a pattern of relatively high density tissue that provides strength with "islands" of low density tissue that provides softness. This requires a significant capital investment as this technology cannot be retrofitted onto an existing tissue machine.

Additives have long been used to create strength in tissue products. In the general paper industry, a number of chemicals have been traditionally applied (Grigoriev et. al., "Strength chemistry for board and tissue production: Scientific outlook and end applications" emira, Technical Paper, 2012). In wet end systems, the objective is typically to apply the chemicals uniformly over the surface and to get uniform absoiption on the fibers (Principles of Wet End Chemistry, Will E. Scott, TAPPI Press, Atlanta, GA (1996)). Absoiption on the "long fiber" portion of the furnish has previously been construed as not absorbing on the fine materials (e.g., fiber materials with largest dimensions smaller than 0.200 mm). The reason for this being that the fine materials have a disproportionately high surface to weight ratio and require high levels of additive. When adding dry strength chemicals, care is typically taken to get the additive to uniformly absorb onto the fibers. This is done by adding the chemicals at locations so as to get good mixing with the furnish so the chemicals can bond to the fibers surfaces uniformly.

SUMMARY

A first aspect of the present invention is directed to a tissue paper article comprising: treated fibers, wherein the treated fibers are fibers that have been treated with at least one strengthening agent; and untreated fibers, wherein the untreated fibers have not been treated with a strengthening agent.

A further aspect of the present invention is directed to a method of manufacturing a tissue paper article, the method comprising: combining treated fibers and untreated fibers to form the tissue paper article, wherein the treated fibers have been treated with at least one strengthening agent and the untreated fibers have not been treated with a strengthening agent.

It is noted that aspects of the invention described with respect to one embodiment, may be incorporated in a different embodiment although not specifically described relative thereto. That is, all embodiments and/or features of any embodiment can be combined in any way and/or combination. Applicant reserves the right to change any originally filed claim and/or file any new claim accordingly, including the right to be able to amend any originally filed claim to depend from and/or incorporate any feature of any other claim or claims although not originally claimed in that manner. These and other objects and/or aspects of the present invention are explained in detail in the specification set forth below. Further features, advantages and details of the present invention will be appreciated by those of ordinary skill in the art from a reading of the figures and the detailed description of the preferred embodiments that follow, such description being merely illustrative of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 provides a schematic of a conventional approach to adding a strengthening agent to enhance the strength of the tissue sheet (left panel), and a schematic of a method according to example embodiments of the present invention (right panel). The amount of starch added per unit weight of the total fiber composition may be the same in both the left and right panels. However, tissue created from a method of the present invention (right panel) may exhibit higher strength and/or equal or increased softness than a tissue created from the conventional method (left panel) as characterized by an EmTec Tissue Softness Analyzer.

Fig. 2 provides a schematic of a conventional method for recycled fiber where a fractionation process is used (left panel), and a schematic of a method according to example embodiments of the present invention (right panel) in which a fractionation process is used to single out fiber that is desired to be treated and this fiber (e.g., the less desirable long fiber fraction) is contacted with a strengthening agent (e.g., starch), which may improve the strengthening effects of these fibers, prior to being combined with other fibers (e.g., untreated fibers and/or small fibers).

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

The present invention is now described more fully hereinafter with reference to the accompanying drawings, in which embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather these embodiments are provided so that this disclosure will be thorough and complete and will fully convey the scope of the invention to those skilled in the art.

The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used in the description of the invention and the appended claims, the singular forms "a," "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.

Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the present application and relevant art and should not be interpreted in an idealized or overly formal sense unless expressly so defined herein. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. All publications, patent applications, patents and other references mentioned herein are incorporated by reference in their entirety. In case of a conflict in terminology, the present specification is controlling.

As used herein, "and/or" refers to and encompasses any and all possible combinations of one or more of the associated listed items, as well as the lack of combinations when interpreted in the alternative ("or").

Unless the context indicates otherwise, it is specifically intended that the various features of the invention described herein can be used in any combination. Moreover, the present invention also contemplates that in some embodiments of the invention, any feature or combination of features set forth herein can be excluded or omitted. To illustrate, if the specification states that a complex comprises components A, B and C, it is specifically intended that any of A, B or C, or a combination thereof, can be omitted and disclaimed.

As used herein, the transitional phrase "consisting essentially of (and grammatical variants) is to be interpreted as encompassing the recited materials or steps "and those that do not materially affect the basic and novel characteristic(s)" of the claimed invention. See, In re Herz, 537 F.2d 549, 551 -52, 190 U.S.P.Q. 461, 463 (CCPA 1976) (emphasis in the original); see also MPEP § 21 1 1.03. Thus, the term "consisting essentially of as used herein should not be interpreted as equivalent to "comprising."

The term "about," as used herein when referring to a measurable value such as an amount or concentration and the like, is meant to encompass variations of ± 10%, ± 5%, ± 1%, ± 0.5%, or even ± 0.1% of the specified value as well as the specified value. For example, "about X" where X is the measurable value, is meant to include X as well as variations of ± 10%, ± 5%, ± 1%, ± 0.5%, or even ± 0.1% of X. A range provided herein for a measurable value may include any other range and/or individual value therein.

As used herein, the terms "increase," "increases," "increased," "increasing," "improve," "enhance," and similar terms indicate an elevation in the specified parameter of at least about 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 100%, 150%, 200%, 300%, 400%, 500% or more.

As used herein, the terms "reduce," "reduces," "reduced," "reduction," "inhibit," and similar terms refer to a decrease in the specified parameter of at least about 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 97%, or 100%.

Provided according to embodiments of the present invention are tissue paper (e.g., non-woven) articles. "Tissue paper" as used herein, refers to grades of paper that include, provide, and/or form toilet tissue, napkins, facial tissue, wipes, kitchen toweling, and non- wovens, but does not include grades of tissue such as those used for wrapping paper in crepe paper. The article may be one-ply (i.e., one sheet) or multi-ply (i.e., multiple sheets, such as, e.g., 2, 3, 4, 5, 6, or more sheets). In some embodiments, a tissue paper article of the present invention has increased strength and/or similar or increased softness compared to a conventional tissue paper article of the same type (e.g., a tissue paper article prepared not in accordance with a method of the present invention).

The inventors of the present invention unexpectedly discovered that a synergistic effect in strength and softness could be achieved by creating differences in the fibers used to form a tissue paper article. As described above, conventional methods take care to uniformly absorb an additive (e.g., a strengthening agent) onto the fibers, such as, e.g., by adding the additive at locations so as to get good mixing with the furnish. The conventional approach is thus contrary to aspects of the present invention where differences in the fibers are intentionally created, which can surprisingly provide a synergistic effect in improved strength and softness.

In some embodiments, one or more (e.g., 1 , 2, 3, 4, or more) strengthening agent(s) may be contacted and/or applied to specific fibers in a paper mix, which may create a network of fibers that may strengthen a tissue paper article (e.g., a tissue sheet), while leaving other fibers in the paper mix and/or tissue paper article untreated. The untreated fibers may contribute to the softness of the tissue paper article and/or may maintain or improve the softness of the tissue paper article. In some embodiments, a method of the present invention maximizes the effect of a strengthening fiber (i.e., a fiber that contributes to the strength of the article, such as, for example, a long fiber) by treating the strengthening fiber with a strengthening agent before forming the tissue paper article (e.g., tissue sheet). This is different from conventional methods for adding strengthening agents to tissue paper articles in that the conventional methods treat the entire batch of pulp, which may improve strength, but can provide an overall decrease in the softness of the article.

In some embodiments, a tissue paper article of the present invention comprises treated fibers and untreated fibers. The treated fibers are fibers that have been treated with a strengthening agent, and the untreated fibers have not been with a strengthening agent. The treated fibers may be present in the article in any suitable amount, such as, e.g., in an amount in a range from about 10%, 15%, 20%, 25%, 30%, 35%, 40% or 45% to about 50%, 55%, 60%), 65% or 70% by weight of the fibers present in the article. In some embodiments, the treated fibers may be present in an amount of about 10%>, 15%, 20%>, 25%, 30%>, 35%, 40%, 45%, 50%, 55%, 60%, 65%, or 70% by weight of the fibers present in the article. Example strengthening agents include, but are not limited to, cationic starches, cationic dry strength additives, native starches, carboxymethyl cellulose, carboxymethyl starches, glyoxalated polyacrylamide (GPAM), polyamide-epichlorohydrin (PAE), cationic polyacrylamide (CPAM), amphoteric PAM, amphoteric starches, polymeric materials including a quaternary amine group, polymers including an amine functional group, chitosan, soy proteins, other plant and/or animal derived proteins, and any combination thereof. In some embodiments, the strengthening agent may be a biopolymer (e.g., starch) and/or modified biopolymer (e.g., a charge-modified and/or cross-linked biopolymer) as described in U.S. Patent Application Publication No. 2017/0002098, International Publication No. WO 2017/091463, and/or International Application No. PCT/US2017/033753, the contents of each of which are incorporated herein by reference in their entirety. In some embodiments, the strengthening agent is a cationic starch, which may have a degree of substitution in a range of about 0.05, 0.06, 0.07, 0.08 or 0.09 to about 0.1 , 0.15, 0.20 or 0.25, a particle size in a range of about 10, 20, 30, 40, 50 or 60, 70, 80, 90, 100, 1 10, 120 or 125 μιη to about 130, 140, 150, 160, 170, 180, 190, 200, 210, 220, 230, 240 or 250 μιη, and/or a solubility in water at room temperature of about 50%, 55%, 60%, 65% or 70% to about 75%, 80%, 85%, 90%, 95% or 100%). In some embodiments, the strengthening agent is a cationic starch, which may have a degree of substitution in a range of about 0.05, 0.06, 0.07, 0.08 or 0.09 to about 0.1 , 0.15, 0.20 or 0.25, a particle size in a range of about 10, 20, 30, 40, 50 or 60, 70, 80, 90, 100, 1 10, 120 or 125 μτη to about 130, 140, 150, 160, 170, 180, 190, 200, 210, 220, 230, 240 or 250 μηι, and/or a solubility in water at temperature of 90°C of about 50%, 55%, 60%, 65% or 70% to about 75%, 80%, 85%, 90%, 95% or 100%.

When a fiber (e.g., cellulosic fiber) is contacted and/or treated with a strengthening agent, all or a portion (e.g., a functional group and/or moiety) of the strengthening agent may adhere to a surface of the fiber, such as, e.g., through a physical bond (e.g., a hydrogen bond, Van deer Waals force, dipole interaction, etc.) and/or may be attached via a chemical bond (e.g., a covalent bond, ionic bond, etc.). In some embodiments, the treated fibers may be chemically modified compared to the untreated fibers. In some embodiments, the treated fibers may be different from the untreated fibers in that they comprise a carboxylic acid functional group and/or cationic moiety that is not present in and/or on the untreated fibers and/or the treated fibers may comprise one or more (e.g., 1 , 2, 3, 4, 5, 6, etc.) additional carboxylic acid functional groups and/or cationic moieties compared to the untreated fibers.

One or more charged moieties may be added to a fiber upon contact and/or treatment with a strengthening agent. The charged moieties may make the charge on the fiber more negative or more positive. For example, the charge on the fiber may become more negative or more positive by 1 meq/g or more, such as, e.g., 2 meq/g, 4 meq/g, 8 meq/g, 16 meq/g, 32 meq/g, 64 meq/g, 128 meq/g, 256 meq/g, 512 meq/g, or 1028 meq/g. In some embodiments, the charge on the fiber may become more negative or more positive in a range of about 1 , 2, 4, 10, 50, 100, 150, or 250 meq/g to about 350, 500, 750, or 1000 meq/g. In some embodiments, the charged moieties may provide the fiber with a net negative charge, a net positive charge, or a neutral charge. In some embodiments, the strengthening agent is amphoteric (i.e., has both negative and positive charges), so the net charge of the fiber may not be effected. The charge can be measured via a number of methods known to those of skill in the art including, but not limited to, streaming potential where the charge on the treated fibers is determined via a titration with a known polymer of opposite charge (Sood, Y. V., Tyagi, R., Tyagi, S., Pande, P. C, Tondon, R., "Surface charge of different paper making raw materials and its influence on paper properties," Journal of Scientific & Industrial Research, 69:300-304 (2010); Wang, F. Hubbe, M. A., "Charge properties of fibers in the paper mill environment. 1. Effect of electrical conductivity," J. Pulp Paper Science 28(10)347-353 (2002); Stenius, P., "Surface chemistry and charge of cellulose fibres," http://www.stepitn.eu/wp-content/uploads/201 l/09/pm36_UMB_Stenius.pdf). In some embodiments, a strengthening agent may enhance the bond strength between fibers (e.g., between treated and/or untreated fibers).

An article of the present invention may have a basis weight in a range from about 15,

20, 25, 30, 35, or 40 grams per meter squared to about 45, 50, 55, 60, 65, 70 or 75 grams per meter squared. The caliper of the article (e.g., sheet) may be measured by DS/EN ISO 12625-3 (Tissue paper and tissue products - Part 3 : Determination of thickness, bulking thickness and apparent bulk density and bulk) and/or may be used to determine the apparent density of the article (e.g., sheet) combination with grammage (basis weight) of the article. The article may be made of layers of fibers, optionally wherein different fibers and/or fiber layers can be found throughout the thickness of the article. These layers may be arranged to increase the strength and/or softness of the article. For example, in some embodiments, an article may comprise at least three fiber layers with a first fiber in the first and third layers and a second fiber in the second layer.

The apparent density of the article may be less than about 450 kg/m³, which includes creping, through air drying, embossing and/or converting to form multiply sheets. In some embodiments, the apparent density of the article may be less than about 450, 400, 350, 300, 250, or 200 kg/m , which includes creping, through air drying, embossing and/or converting to form multiply sheets. In some embodiments, the minimum density can be set by the density at which a continuous web of fibers can no longer be formed. This value depends on the type of fiber used as well as the forming process. Tissue papers formed at low density (e.g., less than about 450 kg/m³) may have their strength properties dominated by the inter- fiber bonding strength in shear modes, peeling modes, and/or tension modes. Due to the overall strength of the article and/or sheet(s), the strength of the fibers themselves may be of little importance. This is contrary to papers formed at densities greater than about 450 kg/m whose strength properties are dependent on a number of factors described by Page ("A theory for the tensile strength of paper," TAPPI JOURNAL 52(4): 674( 1969)) including fiber length, fiber coarseness (mass per unit length), inter-fiber shear bond strength, amount of inter-fiber bonding, and fiber strength.

In some embodiments, an article of the present invention may have a tensile and/or ball burst strength that is increased by at least 5% (e.g., at least about 5%, 10%, 15%, 20%, 25%, 30%), 35%o, 40%), 45%>, 50% or more) compared to a conventional tissue paper article (e.g., of the same type) and/or compared to a tissue paper article (e.g., of the same type) having all fibers treated with a strengthening agent (e.g., the same strengthening agent and/or amount by weight of the total fiber composition as the treated fibers in the article of the present invention). In some embodiments, an article of the present invention exhibits a strength (e.g., tensile and/or ball burst) that is greater than the strength achieved by the same treatment applied to the entire portion of the fiber (i.e., all of the fibers in the article) and forming a sheet in a similar manner. In some embodiments, the net effect is such that when the same amount of treatment (e.g., contact and/or chemical modification with a strengthening agent in the same amount by weight of the total fiber composition) is applied to the fiber source as a whole, the improved strength achieved by treating all the fibers is less than the strength achieved when only a portion (e.g., 10%> - 70%) of the fibers are treated with the strengthening agent and then combined with the untreated portion and used to form the article (e.g., tissue sheet).

In some embodiments, an article of the present invention has a softness that is the same as, substantially the same as, or increased by at least 10% (e.g., at least about 10%, 15%), 20%), 25%, 30%, 35%, 40%, 45%o, 50% or more) compared to a conventional tissue paper article (e.g., of the same type), compared to a tissue paper article (e.g., of the same type) prepared solely from the untreated fibers, and/or compared to a tissue paper article (e.g., of the same type) having all fibers treated with a strengthening agent (e.g., the same strengthening agent and/or amount by weight of the total fiber composition as the treated fibers in the article of the present invention). Softness may be measured by an EmTec Tissue Softness Analyzer, the measurement on the EmTec Tissue Softness Analyzer being the decibels at 6500 Hz of sound frequency also referred to as the TS7 peak. Lower values in this peak are associated with improved softness of the article (e.g., sheet).

The treated and/or untreated fibers of the present invention may be natural fibers and/or synthetic (e.g., man-made) fibers. Example fibers (e.g., treated and/or untreated as described herein) that may be present in an article of the present invention and/or used in a method of the present invention include, but are not limited to, wood pulp fibers, cannabis fibers, cotton fibers, regenerated or spun cellulose fibers, jute fibers, flax fibers, ramie fibers, bagasse fibers, kenaf fibers, rayon fibers, cellulose acetate fibers, polyethylene terephthalate fibers, poly-lactic acid fibers, polyethylene fibers, propylene fibers, starch based fibers, chitin based fibers, chitosan based fibers, lignin based fibers, and/or a combination thereof or a blend composite of two or more fibers. In some embodiments, the treated and/or untreated fibers comprise a blend of two or more different types of fibers, such as, e.g., a blend comprising natural and synthetics fibers. In some embodiments, the treated fibers comprise softwood fibers (e.g., the long portion of the fiber). In some embodiments, all or a portion (e.g., 10%, 25%, 50%, 75%, or more) of the treated and/or untreated fibers may be obtained from mixed office waste and/or recycled pulp and/or paper. In some embodiments, all or a portion (e.g., 10%, 25%, 50%, 75%, or more) of the treated and/or untreated fibers may be a product from a fractionation process, such as, e.g., described in U.S. Patent No. 5,582,685, the contents of which is incoiporated herein by reference in its entirety, or as performed by other fraction methods such as, e.g., screening.

In some embodiments, the treated and/or untreated fibers have a dimension in a range of about 0.2, 0.5, 1 , 2, 3, 4 or 5 mm to about 6, 7, 8, 9 or 10 mm. In some embodiments, the treated and/or untreated fibers have at least one dimension greater than 0.2 mm and no dimension greater than 10 mm.

A method of the present invention may increase the strength of the resulting tissue paper article and/or maintain or increase the softness of the resulting tissue paper article compared to a conventional tissue paper article of the same type (e.g., a tissue paper article prepared not in accordance with a method of the present invention). A method of the present invention may allow for more flexibility in materials selection, the ability to improve the properties of tissue paper articles, and/or the ability to reduce costs of production by reducing basis weight and/or maintaining a similar strength. In some embodiments, a method of the present invention comprises combining treated fibers and untreated fibers to form a tissue paper article. The treated fibers may have been treated with at least one strengthening agent. The untreated fibers have not been treated with a strengthening agent. In some embodiments, combining the treated fibers and the untreated fibers comprises adding the treated fibers in an amount in a range from about 10% to about 70% by weight of the fibers.

The method may comprise contacting (e.g., adding, mixing, spraying, etc.) a strengthening agent to fibers to form the treated fibers. Contacting the strengthening agent to the fibers may comprise contacting a pulp and/or fiber source and the strengthening agent to form the treated fibers. The fibers may be wet or dry. For example, in some embodiments, a strengthening agent is contacted with a slurry (e.g., a fiber slurry) comprising fibers and a suspending medium (e.g., water, ethanol, methanol, acetone, etc.). In some embodiments, a strengthening agent is contacted with dry fibers. Methods of contacting and/or modifying a fiber with a strengthening agent are known to those of skill in the art and may be used in a method of the present invention. In some embodiments, after contacting and/or modifying a fiber with a strengthening agent to form the treated fiber, the treated fiber may be dried. In some embodiments, a treated fiber after drying may have one or more of the same properties (e.g., strength, modification, etc.) as the treated fiber prior to drying.

In some embodiments, a strengthening agent may be contacted to fibers in an amount in a range from about 0.01%, 0.05%, 0.1%, 0.5% or 1% to about 5%, 10%, 15% or 20% by weight of the fibers and/or pulp. In some embodiments, a strengthening agent may be contacted to the fibers in an amount in a range from about 0.1% to about 0.5% or 1% by weight of the fibers and/or pulp. In some embodiments, a strengthening agent may be contacted to fibers in an amount of about 0.01%, 0.05%, 0.1%, 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 1 1%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, or 20% by weight of the fibers and/or pulp.

Contacting the strengthening agent and fibers and/or modification of a fiber fraction to provide the treated fibers may take place at any point in the process for preparing a tissue paper article. In some embodiments, a pulp may be contacted and/or modified with a strengthening agent before it is dried to be sold as market pulp. In some embodiments, a pulp may be contacted and/or modified with a strengthening agent in a paper mill by the addition of the strengthening agent to a portion of the fiber (e.g., the long portion of the fiber (e.g., softwood)). In some embodiments, a method of the present invention comprises identifying, preparing, selecting, and/or providing a fiber fraction. In some embodiments, the fiber fraction may be prepared by selecting a portion of fibers based on size. For example, a fiber fraction including fibers having at least one dimension greater than 0.2 mm and no dimension greater than 10 mm may be identified, prepared, selected, and/or provided. In some embodiments, the fiber fraction may be prepared by splitting the fibers into two separate mixtures (e.g., streams), one for untreated fibers (e.g., about 30%, 35%, 40%, 45% or 50% to about 55%, 60%, 65%, 70%, 75%, 80%, 85% or 90%) and one for treated fibers (e.g., about 10%, 20%, 30%, 40% to about 50%, 60% or 70%). Then, contacting (e.g., adding, spraying, etc.) a strengthening agent with the mixture for treated fibers, but not to the mixture for untreated fibers.

As shown in Fig. 1, left panel, a conventional method for adding a strengthening agent to enhance the strength of a resulting tissue sheet is shown with the method involving combining Southern Bleached Hardwood Kraft (SBHK) and Southern Bleached Softwood Kraft (SBSK) to form a mixture containing about 70% SBHK and 30% SBSK and adding starch to this mixture, which is then used to form handsheets. In contrast, as shown in Fig. 1, right panel, a method of the present invention may contact (e.g., add) a strengthening agent (e.g., a starch) to a mixture containing SBSK to provide treated SBSK (i.e., strengthening agent treated fibers), but the mixture containing SBHK is not contacted with the strengthening agent (e.g., starch) to provide untreated SBHK. Then, the treated SBSK and untreated SBHK are combined form a mixture containing, e.g., about 70% untreated SBHK and 30%) treated SBSK, which is then used to form handsheets.

Referring now to Fig. 2, a method of the present invention may involve a fractionation process. Fractionation processes are known to those of skill in the art, such as, e.g., those described in U.S. Patent No. 5,582,685, the contents of which are incorporated herein by referenced in its entirety. Fig. 2, left panel shows an example fractionation process. In some embodiments, a method of the present invention may comprise performing a fractionation process and contacting (e.g., adding) a strengthening agent (e.g., starch) to the waste containing the less desirable long fiber fraction (i.e., large fibers), which may improve the strengthening effects of these fibers (Fig. 2, right panel).

According to some embodiments of the present invention provided is a method for creating a composite tissue structure where there exist fibers with enhanced bonding characteristics intermixed with fibers that impart softness to the sheet. An article, tissue structure, and/or product of the present invention may be suitable for, configured for, and/or intended for use in hygiene, wiping, toilet tissue, napkin and/or facial tissue applications. In some embodiments, the article is and/or is used in a hygiene product. In some embodiments, the article is a towel, napkin, facial tissue, wipe, or toilet tissue.

The present invention is explained in greater detail in the following non-limiting examples.

EXAMPLES

Example 1

Sheets were formed using hardwood and softwood market pulp. The fiber was disintegrated separately to create a batch of hardwood fiber and a batch of softwood fiber. Cationic starch having a degree of substitution of about 0.1 , a particle size in a range of about 125 μιη to about 250 μη , and a solubility of about 100% in water at room temperature (Tethis, Inc. Raleigh, NC) was dissolved in water at 2 % wt/wt.

In a first set, the two pulp fiber suspensions were combined together at a ratio of 70% hardwood and 30% softwood. The dissolved starch was then added to the combined fiber at 0.25% or 0.5% based on weight of the pulp. The cationic starch was allowed to interact with the fibers for at least 15 minutes before the forming process began. Sheets were then formed according to the North Carolina State University protocol for forming handmade tissue sheets. This process is a modified version of TAPPI Method T 205-sp 95 Forming Handsheets for Physical Testing of Pulp (TAPPI Press, Atlanta, Georgia). The modifications are as follows:

a. Sheets are formed at a target basis weight of 30 grams per meter squared. b. After couching from the forming wire, one blotter is removed and a fresh blotter is placed over the sheet so that the tissue is pinched between the old blotter sheet and the fresh blotter sheet.

c. The "sandwich" of the blotter sheets and the tissue sheet is then passed through a rotating dryer drum five times. The dryer drum is set at an RPM of 2 and the temperature is set at 1 10°C.

d. After drying, the sheets are placed in a TAPPI standard atmosphere overnight.

Note that the sheets are not dried under restraint.

The properties of the tissue sheets were then measured using established methods. The methods are listed in Table 1. Table 1 : Test methods for the evaluation of Tissue Properties.

A second set of tissues sheets was formed using hardwood and softwood market pulp. The fiber was disintegrated separately to create a batch of hardwood fiber and a batch of softwood fiber. Cationic starch (Tethis, Inc. Raleigh, NC), as described above, was then dissolved in water at 2 % wt/wt. The dissolved starch was then added to the fiber at 0.25% or 0.5% based on weight of the pulp uncombined. The cationic starch was allowed to interact with the fibers for at least 15 minutes while still not mixed. Then, the pulp was mixed at a 70% hardwood and 30% softwood ratio. Tissue sheets were then formed according to the method above and tested according to the methods above.

A third set of handsheets was formed and tested using the same methods as for the previous sets with the difference being in how the fibers were prepared before forming the tissue sheets. The same fibers (hardwood and softwood) were used to form these sheets. However, in this set the hardwood fibers had no cationic starch (Tethis Inc., Raleigh, NC), added to them. The softwood portion had 0.83% or 1.7% cationic starch (Tethis Inc. Raleigh, NC), as described above, added. This amount of starch was equal to the amount added to both the hardwood and softwood in the first set of tests. The cationic starch was allowed to interact with the fibers for at least 15 minutes before the forming process began.

The following are detailed examples of how the cationic starch additions were determined for each of the sets of handsheets.

For set one, as an example, 7 grams of hardwood fiber in the form of a pulp slurry was combined with 3 grams of a softwood pulp slurry to form a pulp slurry with 10 grams total of pulp. To this was added 0.025 grams of cationic starch in the form of a 2% concentration solution (i.e., 1.25 grams of the solution).

For set two, as an example, 7 grams of hardwood fiber in the form of a pulp slurry had

0.0175 grams of cationic starch in the form of 2% solution added to it (i.e., 0.875 grams of solution). Three grams of softwood fiber in the form of a pulp slurry had 0.0075 grams of cationic starch in the form of 2% solution added to it (i.e., 0.375 grams of solution). The two pulps were then combined to form tissue sheets.

For set three, as an example, 3 grams of softwood fiber in the form of a pulp slurry had 0.025 grams of cationic starch in the form of 2% solution added to it (i.e., 1.25 grams of solution). This was combined with 7 grams of hardwood fiber in the form of a pulp slurry and tissue sheets were formed from the combined pulp slurry.

A fourth set of tissue sheets was formed using no starch additives at all.

The four different methods of adding the cationic starch were conducted over two independent runs. The result was a difference in the density of these sheets due to one of the runs being exposed to wet pressing as described in TAPPI Method T 205. Table 2 shows the tissue sheets formed and not pressed. The basis weights of the sheets are very similar and

2 3 have a target value of 30 g/m . The density for the sheets ranged from 230 kg/m^J to 249 kg/m³. One can compare the no starch (i.e., the fourth set) to the method two (i.e., the second set). Note that method two would be considered a traditional technology. One observes an increase in the ball burst strength, tensile strength and softness measurements (TS7 and TS750). Using method three (i.e., the third set), there is an improvement in the ball burst strength, tensile strength, and TS7 softness over method two as well as the no starch condition. Table 2: Results from running methods two and three compared to no starch added.

Table 3 shows the results from methods one (i.e., the first set) and two (i.e., the second set). Note that these sheets were pressed, but the density remained below the 450 kg/m³ range for the technology. Table 3: Results from running methods one and two with wet pressing.

The results in Table 3 show improved strength when starch is added compared to the no starch condition. However, in method two, when the starch is added to each fraction before mixing there is a decrease in the strength when compared to the sample with the starch added to the combined fibers. This indicates that simply adding the same amount of starch to the fibers separately does not create a synergistic effect as shown in method three, which was prepared in accordance with an embodiment of the present invention.

Example 2

Mixed office waste recycled pulp will be obtained from a third party. Cationic starch having a degree of substitution of about 0.1 , a particle size in a range of about 125 μιτι to about 250 μιτι, and a solubility of about 100% in water at room temperature (Tethis, Inc. Raleigh, NC) was dissolved in water at 2% wt/wt and used as the strengthening agent. The pulp was fractionated using a PulMac Master Screen with a screen having a mesh size of 40 mesh. The fraction retained on the screen were considered the coarse fraction and composed of primarily longer fibers. The coarse fraction of this process will be treated with a strengthening agent (i.e., cationic starch) in an amount of 0.5% based on the final sheet weight. The fiber that passes through the 40 mesh screen and is retained is primarily composed of smaller fibers. A control sample was made by treating the combined fractionated pulp with the modified starch at 0.5%. Sheets were then formed according to the North Carolina State University protocol for forming handmade tissue sheets. This process is a modified version of TAPPI Method T 205-sp 95 Forming Handsheets for Physical Testing of Pulp (TAPPI Press, Atlanta, Georgia). The modifications are as follows:

a. Sheets are formed at a target basis weight of 30 grams per meter squared.

b. After couching from the forming wire, one blotter is removed and a fresh blotter is placed over the sheet so that the tissue is pinched between the old blotter sheet and the fresh blotter sheet. c. The "sandwich" of die blotter sheets and the tissue sheet is then passed through a rotating dryer drum five times. The dryer drum is set at an RPM of 2 and the temperature is set at 1 10°C.

d. After drying, the sheets are placed in a TAPPI standard atmosphere overnight. 5 Note that the sheets are not dried under restraint.

The properties of the tissue sheets are then measured using established methods. The methods are listed in Table 1.

Table 4 shows the properties of the tissue sheets. These sheets show improved softness and improved ball burst strength.

10

Table 4: Properties of fractionated DIP pulp compared to control.

Example 3

Mixed office waste recycled pulp was obtained from a third party. The fiber was slurried and then split into two portions: one portion consisting of 30% of the fiber and the other portion consisting of 70% of the fiber. The portions were composed of essentially the same size and type of fibers. A first set of handsheets were formed where the 30% portion was then treated with strengthening agent (test sets). Cationic starch having a degree of substitution of about 0.1 , a particle size in a range of about 125 μιη to about 250 μηι, and a solubility of about 100% in water at room temperature (Tethis, Inc. Raleigh, NC) was dissolved in water at 2% wt/wt and used as the strengthening agent. A second set of handsheets were formed where the entire amount of fiber was treated with the same amount of strengthening agent (control sets). Sheets were then formed according to the North Carolina State University protocol for forming handmade tissue sheets. This process is a modified version of TAPPI Method T 205-sp 95 Forming Handsheets for Physical Testing of Pulp (TAPPI Press, Atlanta, Georgia). The modifications are as follows:

Note that the sheets are not dried under restraint.

For comparison, the original pulp will be treated as a whole with an equal amount of starch. Also, sheets will be formed without any starch.

Table 5 shows the properties of tissue sheets when 0.5% or 1.5% (based on final sheet weight) strengthening agent is added to the fiber slurry. It should be noted that when compared to the controls (Control 1 and Control 3) the test samples showed either improved of nearly constant softness and/or improved strength measurement in both test conditions.

Table 5: The properties of Tissue Sheets when 30% of the fiber is preferentially treated with strengthening agent.

Example 4

Sheets were formed using hardwood and softwood market pulp. The fiber was disintegrated separately to create a batch of hardwood fiber and a batch of softwood fiber. Cationic starch having a degree of substitution of about 0.1 , a particle size in a range of about 125 μηι to about 250 μιη, and a solubility of about 100% in water at room temperature (Tethis, Inc. Raleigh, NC) was dissolved in water at 2% wt/wt.

In a first set (control sets), the two pulp fiber suspensions were combined together at a ratio of 60% hardwood (Bleached Eucalyptus Kraft Pulp) and 40% softwood (Northern Bleached Softwood Kraft Pulp). The dissolved starch was then added to the combined fiber at 0%, 0.5%, 1 %, or 1.5% based on weight of the pulp. The cationic starch was allowed to interact with the fibers for at least 15 minutes before the forming process began. Sheets were then formed according to the North Carolina State University protocol for forming handmade tissue sheets. This process is a modified version of TAPPI Method T 205-sp 95 Forming Handsheets for Physical Testing of Pulp (TAPPI Press, Atlanta, Georgia). The modifications are as follows:

a. Sheets are formed at a target basis weight of 30 grams per meter squared.

b. After couching from the forming wire, one blotter is removed and a fresh blotter is placed over the sheet so that the tissue is pinched between the old blotter sheet and the fresh blotter sheet.

Note that the sheets are not dried under restraint.

The properties of the tissue sheets were then measured using established methods. The methods are listed in Table 1.

A second set (test sets) of handsheets were formed and tested using the same methods as for the previous sets with the difference being in how the fibers were prepared before forming the tissue sheets. The same fibers (hardwood (60%) and softwood (40%)) were used to form these sheets. However, in this set the hardwood fibers had no cationic starch (Tethis Inc., Raleigh, NC), added to them. The softwood portion had 1.25%, 2.5%, or 3.75% cationic starch (Tethis Inc., Raleigh, NC), as described above, added. This amount of starch was equal to the amount added to both the hardwood and softwood in the first set of tests. The cationic starch was allowed to interact with the fibers for at least 15 minutes before the forming process began.

The following are detailed examples of how the cationic starch additions were determined for each of the sets of handsheets. For set one (controls), as an example, 6 grams of hardwood fiber in the form of a pulp slurry was combined with 4 grams of a softwood pulp slurry to form a pulp slurry with 10 grams total of pulp. To this was added 0.05 grams of cationic starch (0.5 % starch) in the form of a 2% concentration solution (i.e., 2.5 grams of the solution).

For set two, as an example, 4 grams of softwood fiber in the form of a pulp slurry had 0.05 grams of cationic starch (0.5 % starch) in the form of a 2% concentration solution added to it (i.e., 2.5 grams of solution). This was combined with 6 grams of hardwood fiber in the form of a pulp slurry and tissue sheets were formed from the combined pulp slurry.

Tables 6a and 6b show the results of the tissue sheets formed and not pressed. The basis weights of the sheets are very similar and have a target value of 30 g/m . The density for the sheets ranged from 184 kg/m³ to 200 kg/m³. One can compare the no starch (i.e., Blank) to the method one (control sets). Note that method one (control sets) would be considered a traditional technology. Method two (test sets) can be considered the novel technology. In comparison to the control, the test samples show similar softness (TS7) with improved ball burst strength. At the highest level of addition this is not be observed, which indicates that a range of addition levels are effective and over dosing causes a loss in strength. This is a known phenomenon in tissue making.

Table 6a: Results from running the two methods of cationic starch addition.

Table 6b: Results from running the two methods of cationic starch addition.

Example 5

Sheets were formed using hardwood and softwood market pulp. The fiber was disintegrated separately to create a batch of hardwood fiber and a batch of softwood fiber. A cationic synthetic strengthening agent (polyamidoamine-epichlorohydrin, Kymene 557H, Solenis Inc., Delaware, USA) was used as a strengthening agent. The agent was added on a dry basis to the fiber slurries.

In a first set (control sets), the two pulp fiber suspensions were combined together at a ratio of 60% hardwood (Bleached Eucalyptus Kraft Pulp) and 40% softwood (Northern Bleached Softwood Kraft Pulp). The strengthening agent was then added to the combined fiber at 0%, 0.5%, 1%, or 1.5% based on weight of the pulp. The strengthening agent was allowed to interact with the fibers for at least 15 minutes before the forming process began. Sheets were then formed according to the North Carolina State University protocol for forming handmade tissue sheets. This process is a modified version of TAPPI Method T 205-sp 95 Forming Handsheets for Physical Testing of Pulp (TAPPI Press, Atlanta, Georgia). The modifications are as follows:

a. Sheets are formed at a target basis weight of 30 grams per meter squared.

Note that the sheets are not dried under restraint.

A second set (test sets) of handsheets were formed and tested using the same methods as for the previous sets with the difference being in how the fibers were prepared before forming the tissue sheets. The same fibers (hardwood (60%) and softwood (40%)) were used to form these sheets. However, in this set the hardwood fibers had no strengthening agent added to them. The softwood portion had 1.25%, 2.5%, or 3.75% strengthening agent, as described above, added. This amount of strengthening agent was equal to the amount added to both the hardwood and softwood in the first set of tests. The strengthening agent was allowed to interact with the fibers for at least 15 minutes before the forming process began. The following are detailed examples of how the cationic starch additions were determined for each of the sets of handsheets.

For set one, as an example, 6 grams of hardwood fiber in the form of a pulp slurry was combined with 4 grams of a softwood pulp slurry to form a pulp slurry with 10 grams total of pulp. To this was added 0.05 grams of strengthening agent (dry basis) in the fonn of a solution.

For set two, as an example, 4 grams of softwood fiber in the form of a pulp slurry had 0.05 grams of strengthening agent (dry basis) in the form of a solution added to it. This was combined with 6 grams of hardwood fiber in the fonn of a pulp slurry and tissue sheets were formed from the combined pulp slurry.

Table 7 shows the results for the tissue sheets formed and not pressed. The basis weights of the sheets are very similar and have a target value of 30 g/m². The density for the sheets ranged from 191 kg/m to 217 kg/m . One can compare the no strengthening agent (i.e., Blank) to the method one (control sets). Note that method one (control sets) would be considered a traditional technology. Method two (test sets) can be considered the novel technology. In comparison to the control samples, the test samples show similar softness (TS7) with improved ball burst strength. At the highest level of addition this is not be observed, which indicates that a range of addition levels are effective and over dosing causes a loss in strength. This is a known phenomenon in tissue making.

Table 7: Properties of sheets under various conditions.

Example 6

Sheets were formed using hardwood and softwood market pulp. The fiber was disintegrated separately to create a batch of hardwood fiber and a batch of softwood fiber. A commercially available cationic starch (Sta-lock 300) was used as a strengthening agent. The starch was cooked in a microwave at 2% solid content until it was dissolved. The agent was added on a dry basis to the fiber slurries.

In a first set (control sets), the two pulp fiber suspensions were combined together at a ratio of 60% hardwood (Bleached Eucalyptus Kraft Pulp) and 40% softwood (Northern Bleached Softwood Kraft Pulp). The strengthening agent was then added to the combined fiber at 0%, 0.5%, 1 %, or 1.5% based on weight of the pulp. The strengthening agent was allowed to interact with the fibers for at least 15 minutes before the forming process began. Sheets were then formed according to the North Carolina State University protocol for forming handmade tissue sheets. This process is a modified version of TAPPI Method T 205-sp 95 Forming Handsheets for Physical Testing of Pulp (TAPPI Press, Atlanta, Georgia). The modifications are as follows:

a. Sheets are formed at a target basis weight of 30 grams per meter squared.

Note that the sheets are not dried under restraint.

The properties of the tissue sheets were then measured using established methods.

The methods are listed in Table 1.

For set one, as an example, 6 grams of hardwood fiber in the form of a pulp slurry was combined with 4 grams of a softwood pulp slurry to form a pulp slurry with 10 grams total of pulp. To this was added 0.05 grams of strengthening agent (dry basis) in the form of a solution.

For set two, as an example, 4 grams of softwood fiber in the form of a pulp slurry had 0.05 grains of strengthening agent (dry basis) in the form of a solution added to it. This was combined with 6 grams of hardwood fiber in the form of a pulp slurry and tissue sheets were formed from the combined pulp slurry.

Table 8 shows the results for the tissue sheets formed and not pressed. The basis weights of the sheets are very similar and have a target value of 30 g/m². The density for the sheets ranged from 191 kg/m³ to 229 kg/m³. One can compare the no strengthening agent (i.e., Blank) to the method one (control sets). Note tfyat method one (control sets) would be considered a traditional technology. Method two (test sets) can be considered the novel technology. In comparison to the control, the test samples show similar softness (TS7) with improved ball burst strength. Commercial cationic starch typically has a fairly low charge density. Without willing to be bound to any particular theory, this may mean that higher levels of addition should be added before this becomes effective. Also, the low charge density may make the starch less strongly bonded to the long fiber and thus likely to move onto the short fiber. This would mean that the effect of the technology could be less pronounced.

Table 8: Properties of sheets under various conditions.

Sample ID E [mm/N] D [mm/N] Ball Burst Ball Burst Index (N)/(gsm) Water Adsorption (g/g) Freeness (ml)

Control 1 0.846 0.914 2.102 0.070 6.230 690.000

Test l 0.886 0.986 1.932 0.069 6.451 728.000

Control 2 0.848 0.940 2.700 0.091 6.854 650.000

Test 2 114.981 0.039 2.444 0.080 6.967 680.000

Control3 0.872 1.000 2.598 0.081 6.837 630.000

Test 3 0.826 0.880 3.628 0.111 6.690 642.000

Blank 0.88 1.03 1.91 0.06 5.88 650.00

The foregoing is illustrative of the present invention, and is not to be construed as limiting thereof. The invention is defined by the following claims, with equivalents of the claims to be included therein. All publications, patent applications, patents, patent publications, and other references cited herein are incoiporated by reference in their entireties for the teachings relevant to the sentence and/or paragraph in which the reference is presented.

Claims

THAT WHICH IS CLAIMED IS:

1. A tissue paper article comprising:

treated fibers, wherein the treated fibers are fibers that have been treated with at least one strengthening agent; and

untreated fibers, wherein the untreated fibers have not been treated with a

strengthening agent.

2. The tissue paper article of claim 1 , wherein the treated fibers are present in the article in an amount from about 10% to about 70% by weight of the total fibers present in the article.

3. The tissue paper article of claim 1 or 2, wherein the at least one strengthening agent is selected from the group consisting of cationic starches, cationic dry strength additives, native starches, carboxymethyl cellulose, carboxymethyl starch, glyoxalated polyacrylamide (GPAM), polyamide-epichlorohydrin (PAE), cationic polyacrylamide (CPAM), amphoteric PAM, amphoteric starch, polymeric materials including quaternary amine groups, polymers including amine functional groups, chitosan, soy proteins, other plant and/or animal derived proteins, and any combination thereof.

4. The tissue paper article of any preceding claim, wherein the treated fibers are chemically modified compared to the untreated fibers.

5. The tissue paper article of any preceding claim, wherein the treated fibers comprise at least one carboxylic acid functional group and/or cationic moiety that is different than the untreated fibers and/or at least one additional carboxylic acid functional group and/or cationic moiety compared to the untreated fibers.

6. The tissue paper article of any preceding claim, wherein the treated fibers comprise at least a portion of the strengthening agent adhered to a surface of the treated fiber (e.g., through physical bonds and/or chemical bonds).

7. The tissue paper article of any preceding claim, wherein the article has a basis weight in a range from about 15 grams per meter squared to about 75 grams per meter squared.

8. The tissue paper article of any preceding claim, wherein the article has an apparent density of less than about 450 kg/m³.

9. The tissue paper article of any preceding claim, wherein the article has a tensile and/or ball burst strength that is increased by at least 5% compared to a conventional tissue paper article (e.g., of the same type) and/or compared to a tissue paper article (e.g., of the same type) having all fibers treated with the at least one strengthening agent.

10. The tissue paper article of any preceding claim, wherein the article has a softness (e.g., as measured using an EmTec Tissue Softness Analyzer), that is, on average, the same or increased by at least 5% compared to a conventional tissue paper article (e.g., of the same type) and/or compared to a tissue paper article (e.g., of the same type) prepared solely from the untreated fibers.

1 1. The tissue paper article of any preceding claim, wherein the treated and/or untreated fibers comprise wood pulp fibers, cannabis fibers, cotton fibers, regenerated or spun cellulose fibers, jute fibers, flax fibers, ramie fibers, bagasse fibers, and/or kenaf fibers, optionally wherein the treated and/or untreated fibers are recycled fibers.

12. The tissue paper article of any preceding claim, wherein the treated fibers comprise hardwood and/or softwood fibers (e.g., the long portion of the fiber), optionally wherein the treated fibers comprise softwood fibers.

13. The tissue paper article of any preceding claim, wherein the treated fibers comprise softwood fibers and the untreated fibers comprise hardwood fibers.

14. The tissue paper article of claim 12 or 13, wherein the treated fibers comprise softwood fibers and the treated softwood fibers are present in an amount of about 20%, 25%, 30%, 35% or 40% to about 45%, 50%, 55%, 60%, 65% or 70% by weight of the total fibers present in the article.

15. The tissue paper article of any preceding claim, wherein the article is suitable for and/or configured for use in a hygiene, wiping, toilet tissue, napkin and/or facial tissue application, optionally wherein the article is a towel, napkin, facial tissue, wipe, or toilet tissue.

16. The tissue paper article of any preceding claim, wherein the article is one-ply or is multi-ply.

17. A method of manufacturing a tissue paper article, the method comprising: combining treated fibers and untreated fibers to form the tissue paper article, wherein the treated fibers have been treated with at least one strengthening agent and the untreated fibers have not been treated with a strengthening agent.

18. The method of claim 17, further comprising contacting the at least one strengthening agent to fibers to form the treated fibers.

19. The method of claim 18, wherein contacting the at least one strengthening agent to the fibers comprises contacting a pulp and the at least one strengthening agent to form the treated fibers.

20. The method of claim 19, wherein the at least one strengthening agent is added in an amount of about 0.01%, 0.05%, 0.1% or 0.5% to about 1%, 2%, 3%, 4% or 5% by weight of the pulp.

21. The method of any preceding claim, wherein the fibers and/or pulp comprise hardwood and/or softwood fibers (e.g., the long portion of the fiber), optionally wherein the treated fibers comprise softwood fibers.

22. The method of any preceding claim, wherein the treated fibers comprise softwood fibers and the untreated fibers comprise hardwood fibers.

23. The method of claim 21 or 22, wherein the treated fibers comprise softwood fibers and the treated softwood fibers are present in an amount of about 20%, 25%, 30%, 35% or 40% to about 45%, 50%, 55%, 60%, 65% or 70% by weight of the total fibers present in the article.

24. The method of any preceding claim, wherein the at least one strengthening agent is selected from the group consisting of cationic starches, cationic dry strength additives, native starches, carboxymethyl cellulose, carboxymethyl starch, glyoxalated polyacrylamide (GPAM), polyamide-epichlorohydrin (PAE), cationic polyacrylamide (CPAM), amphoteric PAM, amphoteric starch, polymeric materials including quaternary amine groups, polymers including amine functional groups, chitosan, soy proteins, other plant and/or animal derived proteins, and any combination thereof.

25. The method of any preceding claim, wherein combining the treated fibers and the untreated fibers comprises adding the treated fibers in an amount from about 10% to about 70% by weight of the total fibers present in the article.

26. The method of any preceding claim, wherein the treated fibers are chemically modified compared to the untreated fibers.

27. The method of any preceding claim, wherein the treated fibers comprise at least one carboxylic acid functional group and/or cationic moiety that is different than the untreated fibers and/or at least one additional carboxylic acid functional group and/or cationic moiety compared to the untreated fibers.

28. The method of any preceding claim, wherein the treated fibers comprise at least a portion of the at least one strengthening agent adhered to a surface of the treated fiber (e.g., through physical bonds and/or chemical bonds).

29. The method of any preceding claim, wherein the article has a basis weight in a range from about 15 grams per meter squared to about 75 grams per meter squared.

30. The method of any preceding claim, wherein the article has an apparent density of less than about 450 kg/m³.

31. The method of any preceding claim, wherein the article has a tensile and/or ball burst strength that is increased by at least 5% compared to a conventional tissue paper article (e.g., of the same type) and/or compared to a tissue paper article (e.g., of the same type) having all fibers treated with the at least one strengthening agent.

32. The method of any preceding claim, wherein the article has a softness (e.g., as measured using an EmTec Tissue Softness Analyzer), that is, on average, the same or increased by at least 5% compared to a conventional tissue paper article (e.g., of the same type) and/or compared to a tissue paper article (e.g., of the same type) prepared solely from the untreated fibers.

33. The method of any preceding claim, wherein the treated and/or untreated fibers comprise wood pulp fibers, cannabis fibers, cotton fibers, regenerated or spun cellulose fibers, jute fibers, flax fibers, ramie fibers, bagasse fibers, and/or kenaf fibers, optionally wherein the treated and/or untreated fibers are recycled fibers.

34. The method of any preceding claim, wherein the article is suitable for and/or configured for use in a hygiene, wiping, toilet tissue, napkin and/or facial tissue application and/or article, optionally wherein the article is a towel, napkin, facial tissue, wipe, or toilet tissue.

35. The method of any preceding claim, wherein the article is one-ply or is multiply.

36. The method of any preceding claim, further comprising one or more fractionation steps.

37. The method of any preceding claim, further comprising preparing, selecting, and/or providing fibers having given properties and contacting said fibers with the at least one strengthening agent to form the treated fibers.