Absorbent paper products with unique physical strength properties

Abstract

An absorbent towel paper web having a length and a cross-grain perpendicular to the length, the web comprising: a refined softwood pulp fiber blend comprising about 20% to about 90% softwood pulp fibers by weight based on the dry fiber basis of the paper web, and about 18.5% to about 88.5% softwood pulp fibers by weight based on the dry fiber basis of the tissue paper web (the softwood pulp fibers are optionally refined before being added to the blend); about 0.25% to about 5.0% cationic strengthening polymer by weight based on the dry fiber basis of the tissue paper web; about 10% to about 60% hardwood pulp fiber blend by weight based on the dry fiber basis of the tissue paper web; and about 8% or less moisture by weight; wherein the paper web has a mean square tensile strength in the range of about 6 Nm / g to about 12 Nm / g; and wherein the paper web has a cross-grain wet tensile strength to cross-grain dry tensile strength ratio value in the range of about 0.295 to about 0.35. [Selected Figure] Figure 1

Description

[Technical Field]

[0001] This application claims the benefit of the filing date of U.S. Provisional Patent Application No. 62 / 396,812, filed September 19, 2016.

[0002] FIELD OF THE INVENTION The present invention relates to paper products. More particularly, the present invention relates to absorbent paper products having unique physical strength properties. Even more particularly, the present invention relates to absorbent paper products having high dry tensile strength and a high ratio of cross-grain wet tensile strength to cross-grain dry tensile strength. [Background technology]

[0003] Tissue products, such as facial tissue, paper towels, bath tissue, napkins, and other similar products, are designed to include several important properties. For example, the products should have good bulk, good absorbency, a soft feel, and good strength and durability. Unfortunately, when steps are taken to increase one property of the product, other properties of the product are often adversely affected.

[0004] Inventors have long attempted to balance the level of softwood fiber in their paper structures to ensure sufficient strength of their structures, while at the same time minimizing the adverse effects from higher levels of softwood fiber.

[0005] One example of the problem is demonstrated by the efforts that paper toweling product formulators have made and are working to develop new products with higher in-use wet strength while maintaining or reducing dry strength. However, as formulators use typical paper machine process variables to increase the in-use wet strength of the product, other consumer-desired attributes, such as absorbency and / or softness, typically decrease. The problem formulators address to improve paper toweling is how to increase the in-use wet strength of the towel while maintaining or improving softness and / or absorbency, and / or decrease the softwood content while maintaining or reducing the total product dry strength and increasing sheet softness. All of the standard paper machine process variables that papermakers can use to increase strength typically can adversely affect sheet hand and can negatively impact product absorbency.

[0006] Therefore, there remains a need for novel fibrous paper structures that further optimize the physical product performance of towel products, increasing wet strength without sacrificing softness, absorbency, and papermaking reliability. In particular, there is a need for novel fibrous paper structures that increase wet strength while maintaining or increasing dry strength. Such structures would be particularly beneficial for multi-density papermaking structures, non-limiting examples of which are those produced by Through-Air Dried, Fabric Crepe, NTT, ATMOS, and UCTAD machine processes. Summary of the Invention

[0007] The present invention provides an absorbent towel paper web having a length and a cross-grain perpendicular to the direction of the paper machine on which the towel paper web is manufactured, the web comprising: (a) from about 20% to about 90% by weight of the dry fiber basis of the towel paper web: i.) from about 18.5% to about 88.5% by weight of the dry fiber basis of the towel paper web (the softwood pulp fibers are optionally refined before being added to the blend); ii.) from about 0.25% to about 5.0% by weight of the dry fiber basis of the towel paper web of a refined softwood pulp fiber blend; (b) from about 10% to about 55% by weight of the dry fiber basis of the tissue paper web of a hardwood pulp fiber blend; and (c) less than or equal to about 10% by weight moisture, wherein the paper towel web has a Mean Square Tensile Index in the range of from about 6 Nm / g to about 12 Nm / g. wherein the paper web has a grain wet tensile strength to grain dry tensile strength ratio value in the range of from about 0.20 to about 0.50. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic diagram of one embodiment of a process for producing multi-density absorbent paper towels on a through-air drying paper machine for use in the present disclosure. [Figure 2] FIG. 1 is a schematic diagram of another "New Tissue Technology" ("NTT") process for producing a multi-density absorbent towel web product for use in the present disclosure. [Figure 3] FIG. 1 is a schematic diagram of the Advanced Tissue Molding System "ATMOS" process for producing multi-density absorbent towel web products for use in the present disclosure. [Figure 4] FIG. 1 is a schematic diagram of a no-creping through-air drying technology "UCTAD" process for producing a multi-density absorbent towel web product for use in the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0009] The present disclosure relates to absorbent towel paper webs that have a high wet tensile strength to dry strength ratio while maintaining dry tensile despite having a lower refining energy input to the softwood stream and while maintaining a cationic resin addition constant.

[0010] The paper towel web comprises about 20% to about 90% by weight of a refined softwood pulp fiber mixture, based on the dry fiber basis of the towel paper web. The refined softwood pulp fiber mixture comprises about 18.5% to about 88.5% by weight of softwood pulp fibers, based on the dry fiber basis of the towel paper web. The softwood pulp fibers are optionally refined before being added to the mixture. The softwood pulp fiber mixture also comprises about 0.25% to about 5.0% by weight of a cationic strengthening polymer, based on the dry fiber basis of the towel paper web. The paper towel web also comprises about 10% to about 55% by weight of a hardwood pulp fiber mixture, based on the dry fiber basis of the towel paper web. The paper towel web contains about 10% or less by weight of moisture.

[0011] The paper towel web maintains dry strength as measured by having a mean square tensile index in the range of about 6 Nm / g to about 12 Nm / g, or a dry tensile strength in the range of about 300 N / m to about 600 N / m. The paper towel web has improved wet strength relative to the web's dry strength as measured by having a cross-grain wet tensile strength to cross-grain dry tensile strength ratio value in the range of about 0.20 to about 0.50, preferably about 0.295 to about 0.35.

[0012] As used herein, "paper product" refers to any formed, fibrous, structural product that traditionally, but not necessarily, comprises cellulose fibers. In one embodiment, the paper product of the present invention comprises an absorbent towel product ("paper towel product"). In other embodiments, the paper product of the present invention may comprise a soft sanitary tissue product.

[0013] "Absorbent towel products," as used herein, are a class of paper products designed and manufactured to meet consumer demands for liquid absorption and wet cleaning with a soft hand. Absorbent towel products are manufactured using the same papermaking techniques as sanitary and facial tissue, but the raw materials, papermaking process settings, basis weight, and other ingredients are optimized to provide the desired consumer attributes.

[0014] The paper products of the present disclosure refer to paper products including paper tissue products or paper towel products. The disclosed paper technologies generally include, but are not limited to, conventional felt-pressed or conventional wet-pressed tissue paper, pattern-densified tissue paper, wet-creped tissue paper products, and through-air-drying tissue paper products, whether creped or uncreped. For example, the papermaking process of the present disclosure can utilize adhesive creping, wet-creping, double creping, embossing, wet-pressing, air-pressing, through-air-drying, through-air-drying with creping, through-air-drying without creping, and other steps in forming a paper web. Some examples of such techniques are disclosed in U.S. Patent Nos. 4,529,480, 5,048,589, 5,399,412, 5,129,988, 5,494,554, 5,607,551, 6,398,916, 7,744,726 and 8,388,803.

[0015] When forming a multi-layer towel product, the separate plies can be manufactured from the same process or from different processes as desired. For example, in one embodiment, the tissue or towel web can be a creped through-air drying web formed using processes known in the art.

[0016] To form such a web, an endlessly moving forming fabric, suitably supported and driven by rolls, receives the layered or non-layered papermaking stock flowing from a headbox. A vacuum box is positioned directly below the forming fabric and adapted to remove water from the fibrous furnish to assist in the formation of the web. From the forming wire / fabric, the formed web is transferred by vacuum assistance or mechanical means to a second fabric, which may be wire, felt, or woven, so long as the desired topography is created in the template's structure. The use of a sheet-forming template produces a papermaking structure having multiple fiber-reinforced regions of high local basis weight interconnected with multiple local low basis weight regions. The fabric is supported for movement around a continuous path by multiple guide rolls. A pickup roll designed to facilitate transfer of the web from fabric to fabric may be included to transfer the web.

[0017] The formed web is then dried to a moisture level of less than about 10% by weight moisture, preferably less than about 6% by weight moisture, and more preferably less than about 4% by weight moisture. Preferably, the formed web is dried by blowing heated air through the formed web and then transferring it to the surface of a rotatable heated dryer drum, such as a Yankee dryer. The drying cylinder is optionally provided with a resinous protective coating layer beneath the resinous adhesive coating composition. The resinous adhesive coating composition is preferably rewettable. The process is operated so that the adhesive coating provides sufficient wet tack strength upon transfer of the web to the drying cycle to secure the web during drying. The adhesive resin coating composition also maintains flexibility when dried so that the web can be removed from the drying cylinder without significant sheet damage once dryness is achieved. The web may be transferred directly from the through-drying fabric to the Yankee if the drying fabric has a topography, or preferably, transferred to an impression fabric, which is then used to transfer the web to the Yankee dryer. The web is then removed from the dryer drum by a creping blade. Creping the web further reduces internal bonding within the web, increasing softness and absorbency.

[0018] In other embodiments, the base web is formed by a non-creping through-air drying process. Related non-creping through-air drying tissue processes are described, for example, in U.S. Patent Nos. 5,656,132 and 6,017,417.

[0019] The fibrous structures according to the present invention may be in the form of through-air dried fibrous structures, differential density fibrous structures, differential basis weight fibrous structures, wet-laid fibrous structures, air-laid fibrous structures, creped or uncreped fibrous structures, pattern-densified or non-pattern-densified fibrous structures, compressed or uncompressed fibrous structures, double recreped fibrous structures (well known in the art and exemplified in U.S. Pat. Nos. 3,301,746, 3,974,025, 4,191,609 and 4,637,859, 6,398,906 and 8,388,803).

[0020] The absorbent towel paper web of the present disclosure has a longitudinal grain and a cross grain perpendicular to the longitudinal grain. "Mach-de-sieve" (MD) and "cross-de-sieve" (CD) are defined herein as follows: The "longitudinal grain" of a paper web is the direction in the plane of the paper web that is parallel to the length of the paper machine. The "cross-de-sieve" of a paper web is the direction in the plane of the paper web that is perpendicular to the length of the paper machine and is therefore perpendicular to the longitudinal grain. The total dry tensile is the sum of the longitudinal and cross-de-sieve tensiles.

[0021] As used herein, the phrase "papermaking furnish" refers to an aqueous mixture of either cellulosic or non-cellulosic fibers, papermaking performance aids (strength, absorbency, or softness improvement), fillers, and other papermaking process materials used to form a papermaking web. Cellulosic fibers contemplated are standard "commercially available" materials sold as softwood pulp fibers, e.g., bleached softwood kraft, hardwood pulp fibers, e.g., bleached hardwood kraft, non-wood fibers, recycled fibers, synthetic polymer fibers, and / or eucalyptus bleached kraft pulp, and do not include fibrous materials modified to enhance surface bonding properties, such as enhanced carboxylated fibers as taught in Patent 6,379,494 or similar methods of fiber modification.

[0022] The absorbent towel paper web of the present disclosure comprises from about 20% to about 90%, preferably from about 30% to about 80%, more preferably from about 40% to about 70%, and even more preferably from about 50% to about 60% of a refined softwood pulp fiber blend comprising softwood pulp fibers and a cationic strengthening polymer.

[0023] As used herein, the phrase "weight percent (%) on a dry fiber basis" refers to the percentage of the referenced material component, including any carrier and / or delivery vehicle, to the dry final fiber web once all water and other volatile materials have been removed from the papermaking web.

[0024] "Fiber," as used herein, refers to an elongated physical structure whose apparent length significantly exceeds its apparent diameter, i.e., having a length-to-diameter ratio of at least about 10 and less than 200. Fibers having non-circular cross-sections and / or tubular shapes are common; the "diameter" in this case can be considered to be the diameter of a circle having a cross-sectional area equal to that of the fiber. More specifically, as used herein, "fiber" refers to fibers that make up fibrous structures. The present invention contemplates the use of fibers that make up various fibrous structures, such as, by way of example, natural fibers, e.g., cellulose nanofilaments and / or wood pulp fibers, non-wood fibers, or any suitable fibers and any combination thereof.

[0025] Fibers that make up the natural fibrous structures useful in the present invention include animal fibers, mineral fibers, plant fibers, man-made spun fibers, and engineered fibrous elements, such as cellulose nanofilaments. Animal fibers can be selected from the group consisting of wool, silk, and mixtures thereof. Plant fibers can be derived from plants selected from the group consisting of wood, cotton, cotton linters, flax, sisal, abaca, hemp, hespera arborescens, jute, bamboo, bagasse, espera grass, straw, jute, hemp, milkweed fluff, kudzu, corn, sorghum, gourd, agave, trichomes, loofah, and mixtures thereof.

[0026] Wood fibers, often referred to as wood pulp, are liberated from their source by any one of a number of chemical pulping processes well known to those skilled in the art, including kraft (sulfate), sulfite, polysulfide, soda pulping, etc. Additionally, fibers may be liberated from their source using mechanical and semi-chemical processes, including, for example, logwood, thermomechanical pulp, chemomechanical pulp (CMP), chemi-thermomechanical pulp (CTMP), alkaline peroxide mechanical pulp (APMP), and neutral semi-chemical sulfite pulp (NSCS), which are also contemplated. Pulp may be whitened, if desired, by any one or combination of processes well known to those skilled in the art, including the use of chlorine dioxide, oxygen, alkaline peroxides, etc. However, chemical pulps may be preferred because they impart superior hand and / or desirable tissue sheet properties. Pulp derived from both deciduous trees (hereinafter referred to as "hardwood") and coniferous trees (hereinafter also referred to as "softwood") may be used, and / or fibers derived from non-woody plants may be used together with artificial fibers. Hardwood, softwood, and / or non-woody fibers may be blended, or alternatively, deposited in layers to provide a layered and / or stratified web. U.S. Patent Nos. 4,300,981 and 3,994,771 disclose the layering of softwood and hardwood fibers. Fibers derived from recycled paper, as well as other non-fibrous materials, such as adhesives used to facilitate the original papermaking and paper processing, are also applicable to the present invention. Wood pulp fibers may be short (typical of hardwood fibers) or long (typical of softwood fibers and some non-woody fibers).

[0027] Examples of softwood fibers that can be used in the paper towel web of the present invention include, but are not limited to, fibers derived from pine, spruce, fir, larch, hemlock, cypress, and cedar. Softwood fibers derived from the Kraft process and resulting from more northern climates may be preferred. These are often referred to as Northern Bleached Softwood Kraft (NBSK) pulp.

[0028] The softwood pulp fiber mixture of the absorbent towel paper web of the present disclosure comprises from about 18.5% to about 88.5% by weight, preferably from about 25% to about 75% by weight, more preferably from about 35% to about 65% by weight, and even more preferably from about 45% to about 55% by weight softwood pulp fibers, based on the dry fiber basis of the towel paper web.

[0029] The softwood pulp fibers may optionally be treated to enhance bonding prior to addition to the softwood pulp fiber mixture. This fiber preparation may include a mechanical refining treatment, whereby the fibers are compressed and / or subjected to high shear to make the fibers softer and produce increased fiber-to-fiber bonding area due to fiber fibrillation, fiber swelling, and increased fiber flexibility. Refining may be carried out by any means known to those skilled in the papermaking art. It has been unexpectedly found that mechanical refining may be less than about 20 kilowatt-hours per bone dry ton (kWh / bdt), preferably less than about 10 kWh / bdt, and more preferably, the fibers may be unrefined and still provide enhanced wet strength, maintain constant chemical loading, and maintain paper web dry strength.

[0030] Optional treatment to enhance fiber bonding is accomplished by chemical treatment or "chemical refining" as known in the pulp and papermaking arts to increase fiber-to-fiber bonding area through fiber fibrillation, fiber swelling, and thereby also increasing fiber flexibility.

[0031] Non-limiting examples of short hardwood fibers include fibers from a fiber source selected from the group consisting of acacia, eucalyptus, maple, oak, aspen, birch, cottonwood, alder, ash, cherry, elm, hickory, poplar, rubber, walnut, black locust, sycamore, beech, catalpa, sassafras, gmelin, albizia, and magnolia.

[0032] The absorbent towel paper web comprises a hardwood pulp fiber blend comprising from about 10% to about 55%, preferably from 20% to about 45%, and more preferably from about 30% to about 40% hardwood pulp.

[0033] Different embodiments of the absorbent towel paper web of the present invention may also include additional pulp fibers, so long as their individual surfaces are not altered.

[0034] Recycled fibers can be added to the furnish in any amount. Any suitable recycled fiber can be used, although recycled fibers having relatively low levels of groundwood pulp are often preferred, for example, recycled fibers having a lignin content of less than 15% by weight, or less than 10% by weight, may be preferred depending on the furnish mixture and application used.

[0035] "Synthetic polymer fiber" and similar terms refer to fibers produced from synthetic polymers, such as polyesters, nylons, and polyolefins. Polyesters are generally obtained from aliphatic or aromatic dicarboxylic acids and saturated aliphatic or aromatic diols by known polymerization techniques. Preferred aromatic diacid monomers are lower alkyl esters, such as the dimethyl esters of terephthalic or isophthalic acid. Typical aliphatic dicarboxylic acids include adipic acid, sebacic acid, azelaic acid, dodecanedioic acid, or 1,4-cyclohexanedicarboxylic acid. Preferred aromatic dicarboxylic acids, or their esters or anhydrides, are esterified or transesterified and polycondensed with saturated aliphatic or aromatic diols. Typical saturated aliphatic diols include preferably lower alkane-diols, such as ethylene glycol. Typical alicyclic diols include 1,4-cyclohexanediol and 1,4-cyclohexanedimethanol. Typical aromatic diols include aromatic diols such as hydroquinone, resorcinol, and naphthalenediol isomers (1,5-; 2,6-; and 2,7-). Various mixtures of aliphatic and aromatic dicarboxylic acids and saturated aliphatic and aromatic diols can also be used. Most typically, aromatic dicarboxylic acids are polymerized with aliphatic diols to produce polyesters, such as polyethylene terephthalate (terephthalic acid + ethylene glycol). In addition, aromatic dicarboxylic acids can be polymerized with aromatic diols to produce wholly aromatic polyesters, such as polyphenylene terephthalate (terephthalic acid + hydroquinone).Examples of polyesters include polyethylene terephthalate; poly(1,4-butylene) terephthalate; and 1,4-cyclohexylene dimethylene terephthalate / isophthalate copolymers, and aromatic dicarboxylic acids such as isophthalic acid, bibenzoic acid, naphthalene dicarboxylic acids such as 1,5-, 2,6-, and 2,7-naphthalene dicarboxylic acids; 4,4-diphenylene dicarboxylic acid; bis(p-carboxyphenyl)methanoic acid; ethylene bis-p-benzoic acid; 1,4-tetramethylene bis(p-oxybenzoic acid); ethylene bis(p-tetramethylene acid); 1,3-trimethylene bis(p-oxybenzoic acid); and 1,4-tetramethylene bis(p-oxybenzoic acid), as well as 2,2-dimethyl-1,3-propanediol; cyclohexanedimethanol and compounds of the general formula HO(CH). n aliphatic glycols of OH (where n is an integer from 2 to 10), such as diols selected from the group consisting of ethylene glycol; 1,4-tetramethylene glycol; 1,6-hexamethylene glycol; 1,8-octamethylene glycol; 1,10-decamethylene glycol; and 1,3-propylene glycol; and diols of the general formula HO(CHCHO) n Polyethylene glycols of H (where n is an integer from 2 to 10,000), and other linear homopolymer esters derived from aromatic diols such as hydroquinone, resorcinol, and the isomers of naphthalenediol (1,5-; 2,6-; and 2,7). One or more aliphatic dicarboxylic acids, such as adipic acid, sebacic acid, azelaic acid, dodecanedioic acid, or 1,4-cyclohexanedicarboxylic acid, may also be present.

[0036] Suitable polyolefin resins include materials produced by conventionally polymerizing olefins such as ethylene, propylene, butene-1, and pentene-1,4-methylpent-1-ene. Useful polyolefins for fibers are high-density polyethylene (HDPE) and polypropylene. Other polyolefin homopolymers and copolymers of ethylene may be used in the practice of this invention. Such other polyolefins include low-density polyethylene (LDPE), very low-density polyethylene (VLDPE), linear low-density polyethylene (LLDPE), and polybutylene (PB). However, these other polyolefins may be blended with other polyolefins, such as polypropylene or high-density polyethylene (HDPE).

[0037] Nylon or polyamide resins useful in the practice of the invention are well known in the art and include semi-crystalline and amorphous resins, which may be produced, for example, by the condensation polymerization of equimolar amounts of diamines and saturated dicarboxylic acids containing 4 to 12 carbon atoms, by ring-opening polymerization of lactams, or by copolymerization of polyamides with other components to form, for example, polyether-polyamide block copolymers. Examples of polyamides include polyhexamethylene adipamide (nylon 66), polyhexamethylene azelamide (nylon 69), polyhexamethylene sebacamide (nylon 610), polyhexamethylene dodecanoamide (nylon 612), polydodecamethylene dodecanoamide (nylon 1212), polycaprolactam (nylon 6), polylaurinlactam, poly-11-aminoundecanoic acid, and copolymers of adipic acid, isophthalic acid, and hexamethylenediamine.

[0038] Synthetic polymer fibers are generally hydrophobic compared to cellulose and lack anionic sites for bonding to wet strength resins or sufficient hydroxyl groups to effectively hydrogen bond to pulp-derived fibers. Suitable fibers for use in connection with this invention include melt-spun fibers, melt-blown fibers, splittable fibers having multiple segments, and splittable bicomponent fibers, among others, which can be split into their segments by refining in a disc refiner. One suitable fiber available from Fiber Innovation Technology is a 16-segment, 2-denier nylon / polyester bicomponent fiber having a characteristic fineness of 0.125 denier, described below.

[0039] Splittable fiber preparation to produce splittable fibers is generally known in the context of thermoplastic fibers, where the fiber has segments formed of different polymers. See, for example, U.S. Patent No. 5,759,926 to Pike et al., U.S. Patent No. 5,895,710 to Sasse et al., and U.S. Patent Application Publication No. 2003 / 0203695 (U.S. Patent Application No. 10 / 135,650) to Polanco et al.

[0040] Splittable fibers produced and utilized in connection with this invention may have a split pie shape, an islands-in-the-sea configuration, a side-by-side configuration, a hollow configuration, etc. See U.S. Patent No. 4,735,849 to Murakami et al., Figures 6A-6D, and U.S. Patent Application Publication No. US 2002 / 0168912 (U.S. Patent Application Serial No. 09 / 852,888), Figures 2-9. Splittable fibers are suitably disintegrated prior to incorporation into the furnish as described below.

[0041] Artificial fibers also contemplated in this invention are formed by using a cellulose dope prepared through multiple solvents known to those skilled in the art. The dope can be spun into fibers that can be used or further fibrillated and incorporated into absorbent sheets. Without being limited by theory, synthetic celluloses such as lyocell are contemplated, along with modified lyocells that have been reduced in size through purification and other methods to create smaller fibers and fiber segments. U.S. Patent No. 7,718,036 discloses various possible solvents and the inclusion of fibrillated roselle in tissue and towel structures.

[0042] During fiber preparation for papermaking operations, long-fiber and some short-fiber pulp undergo mechanical or chemical processing, whereby the fibers are compressed, subjected to high shear, and / or chemically treated to make them softer and to produce increased fiber-to-fiber bonding area due to fiber fibrillation, fiber swelling, and increased fiber flexibility. Those skilled in the art will recognize that the three main products of refining pulp fibers are: 1) a percentage of fibers that are completely unaffected by refining intensity and consistency; 2) a significant percentage of fibers are fibrillated, which delaminates the fiber cell walls and exposes microfibrils that remain attached to the original fiber; and 3) a percentage of fibers and microfibrils are cut or mechanically broken into very small pieces (less than 200 microns in length); this fraction is referred to as the ultrafine fiber fraction. These ultrafine fibers can be primary (those present in natural wood sources) or secondary (those created during the refining process). What was discovered was that by varying the refining intensity, concentration and other processing conditions, new fiber components called cellulose nanofilaments could be created, and by optimizing the processing steps and unit operations, a final pulp fiber stream containing more than 40% individualized cellulose nanofilaments could be produced.

[0043] These "cellulose nanofilaments" can be used in embodiments of the present invention. They may be derived from either softwood and / or hardwood and, as such, may contain fibrous elements of softwood or hardwood. The cellulose nanofilament size and high aspect ratio distinguish this material as a unique fiber class and are not characterized as either softwood or hardwood materials. By high aspect ratio, we mean that the fiber length divided by the fiber width is at least 200 to about 5,000, preferably greater than about 600 to about 1,000. Cellulose nanofilaments have an average width in the nanometer range, e.g., about 30 nm to about 500 nm, and an average length in the micrometer range or beyond, e.g., greater than about 10 μm, preferably about 100 μm to about 2 mm, more preferably about 200 μm to about 1 mm, and even more preferably about 300 μm to about 500 μm. Such cellulose nanofilaments can be obtained, for example, from processes that use only mechanical means, such as the method disclosed in U.S. Patent Application Publication No. 2013 / 0017394, filed January 19, 2012. Additionally, cellulose nanofilaments can be produced from a variety of processes, so long as a specific geometric shape is maintained. Processes used to make cellulose nanofilaments include, but are not limited to, modified refining equipment, homogenizers, ultrasonic fiber treatment, and chemical fiber treatment, including enzyme fiber modification.

[0044] In the article "Nanocellulose Patent Trends: A Comprehensive Review on Patents on Cellulose Nanocrystals, Microfibrillated, and Bacterial Cellulose," Charreau et al., Nanotechnology, 2013, 7, 56-80, the authors review the various terms that have been used to refer to microfibrillated cellulose (MFC) over the years, and "cellulose nanofilament" can apply to these general terms. The "cellulose nanofilament" material of the present disclosure is specifically the result of the process disclosed in publication US20130017394A1 to Hua, X. et al., entitled "High aspect ratio cellulose nanofilaments and method for their production." The material produced by this process is unique in that the disclosed process produces cellulose nanofilaments with a significantly higher aspect ratio (length / width) than previously disclosed materials.

[0045] Cellulose nanofilaments are structurally very different from other cellulose fibers, such as microfibrillated cellulose (MFC) or nanofibrillated cellulose (NFC), prepared using other methods for mechanical degradation of wood pulp fibers, in that they contain at least 40%, preferably 75%, and more preferably 90% by weight of fibrillated cellulose material filaments with a maximum filament length of 300-350 μm and a diameter of approximately 100-500 nm. The fibrillated cellulose material in NFC typically has a length of less than 100 μm, while the fibrillated cellulose material in NFC typically has a length of less than 1 μm. However, it should be recognized by those skilled in the art that similar fibrillated cellulose materials produced using mechanical means are not homogeneous materials with a single dimensional value in the production of cellulose nanofilament materials. The preferred blends of cellulose nanofilament materials described above and purified pulp streams containing >50% cellulose nanofilaments within the purified pulp stream are the basis of this invention.

[0046] Another anticipated application of cellulose nanofilaments, possible with embodiments contemplated by this invention, is the inclusion of a small percentage of either pure cellulose nanofilaments and / or a mixture of cellulose nanofilaments and other refined products into virgin or recycled pulp streams before transport to the papermaking site. In this way, a virgin fiber source can be augmented with cellulose nanofilaments, and the cellulose nanofilaments can then be added to the papermaking process without introducing a new fiber dosing stream. Dosing cellulose nanofilaments with cellulose at the pulp production facility could produce what has been called a "superpulp" with properties only possible through cellulose nanofilament inclusion. Therefore, many different methods for cellulose monofilament inclusion are contemplated by this invention, including, but not limited to, direct pure cellulose nanofilament inclusion with a mixture of cellulose nanofilaments and other refinery by-products (with a preferred nanocellulose content greater than 50%), or cellulose nanofilaments added by inclusion in virgin or recycled fibers prior to inclusion at the paper mill.

[0047] The phrase "fibrillated cellulose fibers," as used herein, refers to cellulose fibers that have undergone a mechanical or chemical treatment during which individual cellulose filaments or bundles thereof are liberated from the body of the fiber but remain attached to the fiber at one end, creating a larger bonding area and increased fiber-to-fiber contact. The extent of the treatment determines the number of cellulose nanofilaments released from the fiber.

[0048] As used herein, the phrase "non-cellulosic fibers" refers to a group of papermaking fibers composed of either natural or artificial fibers composed of materials other than cellulose. Non-cellulosic fibers include, but are not limited to, man-made spun fibers, fibers of animal origin, and / or microalgae. Additionally, the fibers forming the products of the present invention may be spun from a polymer melt composition via a suitable spinning operation, such as meltblowing and / or spinbonding, and / or they may be obtained from natural sources. Such fibers may be monocomponent and / or multicomponent. For example, the fibrous elements may include bicomponent fibers and / or filaments. The bicomponent fibers and / or filaments may be in any form, such as side-by-side, sheath-core, islands-in-sea, etc. Non-limiting examples of filaments include meltblown and / or spunbonded filaments. Non-limiting examples of polymers that can be spun into filaments include natural polymers such as starch, starch derivatives, celluloses such as rayon and / or lyocell, and cellulose derivatives, hemicellulose, hemicellulose derivatives, and synthetic polymers, including, but not limited to, thermoplastic polymer filaments such as polyester, nylon, polyolefins such as polypropylene filaments, polyethylene filaments, and biodegradable thermoplastic fibers such as polylactic acid filaments, polyhydroxyalkanoate filaments, polyesteramide filaments, and polycaprolactone filaments. Non-limiting examples of fibers include pulp fibers, such as wood pulp fibers, and synthetic staple fibers such as polypropylene, polyethylene, polyester, their copolymers, rayon, glass fiber, and polyvinyl alcohol fibers. Staple fibers can be produced by spinning a filament tow and then chopping two of the tows into segments less than 5.08 cm (2 in.) long to produce fibers.

[0049] As used herein, the phrase "cellulose microfiber" refers to a class of fibrous materials having a length of less than 200 microns. These materials may include primary materials in trees, or materials of natural origin, or they may be classified as secondary, produced either by pulping and / or handling of pulp fibers, and therefore may contain fiber sections and / or cellulose nanofilament sections. Microfiber is not a homogeneous material, but is merely used to describe a class of materials with a defined length limit.

[0050] Preferred embodiments of the absorbent towel paper web of the present disclosure contain from about 0.05 to about 20.0%, preferably from about 1.0% to about 10.0%, and more preferably from about 2.0% to about 5.0% cellulose nanofilaments.

[0051] Cationic reinforcing polymers useful in this invention include, but are not limited to, cationic water-soluble resins. These resins impart wet strength to paper sheets and are well known in the papermaking art. Such resins include polyamide epichlorohydrin (PAE), urea-formaldehyde resins, melamine formaldehyde resins, polyacrylamide resins, dialdehyde starch, and mixtures thereof.

[0052] In some embodiments, other strength agents can be used to further enhance the strength of the tissue product. As used herein, a "wet strength agent" is any material that, when added to pulp fibers, can provide the resulting web or sheet with a wet geometric tensile strength to dry geometric tensile strength ratio greater than about 0.1. Typically, these are referred to as "permanent" or "temporary" wet strength agents. As is well known in the art, temporary and permanent wet strength agents can sometimes also function as dry strength agents, enhancing the strength of the tissue product when dry. The list of optional chemical ingredients is intended to be largely exemplary in nature and is not meant to limit the scope of the present invention. Other materials may also be included as long as they do not interfere with or diminish the benefits of the present invention.

[0053] Wet strength agents can be applied in various amounts depending on the desired properties of the web. For example, in some embodiments, the total wet strength agent added can be about 0.5 to 50 kg / T, in some embodiments, 2 to about 15 kg / T, and in some embodiments, about 3 to about 5 kg / T of strength agent can be incorporated into any layer of a multi-layer tissue web. Cationic wet strength resins useful in this invention include, but are not limited to, cationic water-soluble resins. These resins impart wet strength to paper sheets and are well known in the papermaking art. These resins can impart either temporary or permanent wet strength to fibrous sheets. Such resins include polyamide epichlorohydrin (PAE), urea-formaldehyde resins, melamine formaldehyde resins, polyacrylamide resins, dialdehyde starch, and mixtures thereof.

[0054] Strength additives may be selected from the group consisting of permanent wet strength resins, temporary wet strength resins, dry strength additives, and mixtures thereof. If permanent wet strength is desired, the chemical papermaking additives may be selected from the following group of chemicals: polyamide epichlorohydrin, polyacrylamide, insolubilized polyvinyl alcohol; ureaormaldehyde; polyethyleneimine; and chitosan polymers. Polyamide epichlorohydrin resins are cationic wet strength resins and have been found to be particularly useful. Suitable types of such resins are described in U.S. Patent Nos. 3,700,623, issued October 24, 1972, and 3,772,076, issued November 13, 1973 (both to Keim). One commercial source of useful polyamide-epichlorohydrin resins is Solenis LLC. of Wilmington, Del., which markets such resins under the trade name KYMENE® 557H.

[0055] Polyacrylamide resins have also found utility as wet strength resins. These resins are described in U.S. Patent No. 3,556,932, issued January 19, 1971, to Coscia et al., and U.S. Patent No. 3,556,933, issued January 19, 1971, to Williams et al. One commercial source of polyacrylamide resins is Kemira Oyj of Helsinki, Finland, which markets one such resin as Fennorez.

[0056] Still other water-soluble cationic resins that find utility in this invention are urea-formaldehyde and melamine-formaldehyde resins. The more common functional groups in these multifunctional resins are nitrogen-containing groups, such as amino groups and methylol groups attached to the nitrogen. Polyethyleneimine-type resins may also find utility in this invention.

[0057] When temporary wet strength is desired, the chemical papermaking additives can be selected from the following group of chemicals: cationic dialdehyde starch-based resins (e.g., Caldas produced by Japan Carlet, National Starch 78-0080, or Cobond 1000, both produced by National Starch and Chemical Corporation); and dialdehyde starch. Modified starch temporary wet strength resins are also described in U.S. Pat. No. 4,675,394, issued June 23, 1987, to Solarek et al. Preferred temporary wet strength resins include those described in U.S. Pat. No. 4,981,557, issued January 1, 1991, to Bjorkquist. Another example of a preferred temporary wet strength resin is a commercially available modified polyacrylamide resin manufactured by Fennorez, Kemira Oyj, Helsinki, Finland. When dry strength is desired, the chemical papermaking additives can be selected from the following group of chemicals. Polyacrylamide (e.g., a combination of Cypro 514 and ACCOSTRENGTH 711 produced by American Cyanamid of Wayne, NJ); starch (e.g., corn starch or potato starch); polyvinyl alcohol (e.g., AIRVOL 540 produced by Air Products Inc. of Allentown, Pa.); guar or locust bean gum; and / or carboxymethylcellulose (e.g., Calexes from CPKelco, Atlanta, GA). Generally, starches suitable for practicing the present invention are characterized by water solubility and hydrophilicity. Exemplary starch materials include corn starch and potato starch, although this is not intended to limit the scope of suitable starch materials; and waxy corn starch, commercially known as amioca starch, is particularly preferred. Amioca starch differs from common corn starch in that it is entirely amylopectin, whereas common corn starch contains both amylopectin and amylose.The various unique properties of Amioca starch are further described in "Amioca - The Starch From Waxy Corn," H.H. Schopmeyer, Food Industries, December 1945, pp. 106-108 (Vol. pp. 1476-1478). The starch may be in granular or dispersed form, with the granular form being preferred. The starch is preferably thoroughly cooked to induce granular swelling. More preferably, the starch granules are swollen by cooking to a certain extent just prior to dispersion of the starch granules. Such highly swellable starch granules are referred to as "fully cooked." Conditions for dispersion generally vary depending on the size of the starch granules, the crystallinity of the granules, and the amount of amylose present. Fully cooked Amioca starch can be prepared, for example, by heating an aqueous slurry of starch granules at about 4% concentration at about 190°F (about 88°C) for about 30 to about 40 minutes. Other exemplary starch materials that can be used include modified cationic starches, such as those available from National Starch and Chemical Company (Bridgewater, NJ), which have been modified to have nitrogen-containing groups, e.g., amino groups and methylol groups attached to the nitrogen. Such modified starch materials have primarily been used as pulp furnish additives to increase wet and / or dry strength. However, when applied to tissue paper webs according to this invention, they may have a reduced effect on wet strength compared to wet-end additions of the same modified starch material. Given that such modified starch materials are more expensive than unmodified starch, the latter has generally been preferred. These wet and dry strength resins can be added to the pulp furnish in addition to being added by the process described in this invention. It should be understood that the addition of chemical compounds, such as the wet strength and temporary wet strength resins described above, to the pulp furnish is optional and not required for the practice of the present development.

[0058] In a preferred embodiment of the process of the present invention, the cationic reinforcing polymer is added to the furnish in an amount ranging from about 0.25% to about 5.0%, preferably from about 0.5% to about 3.0%, and more preferably from about 1.0% to about 2.0%, by weight of the resulting absorbent towel or sanitary tissue product on a dry fiber basis. Generally, processes for making absorbent towel products add higher levels of polymer, where the polymer is added up to about 5.0%, preferably up to about 3.0%, and more preferably up to about 1.5%. Conversely, processes for producing sanitary tissue products add slightly lower levels of reinforcing polymer, where the polymer is added up to about 3.0%, preferably up to about 1.5%.

[0059] It is understood and contemplated in this disclosure that polymers and polymer solutions may be produced now or in the future that have higher concentrations or activity levels than those currently available to paper manufacturers, and which may be embodiments that would be equivalent to absorbent towel paper webs at levels below the lower limits disclosed in this disclosure.

[0060] The fibrous structures of the present disclosure may be homogeneous or layered. If layered, the fibrous structures may comprise at least 2 and / or at least 3 and / or at least 4 and / or at least 5 layers.

[0061] "Weight" is defined herein as lbs / 3000ft 2 or g / m 2 The basis weight is the weight per unit area of ​​the sample reported in metric digits. The fibrous towel structures and / or sanitary tissue products of the present invention may exhibit a basis weight of from 10 g / m to about 120 g / m and / or from about 14 g / m to about 80 g / m and / or from about 20 g / m to about 60 g / m.

[0062] The weight is calculated based on a certain area (m 2and weighing the sample(s) of the fibrous structure according to the present invention and / or paper product containing such fibrous structure on a top-loading balance having a minimum resolution of 0.01 g. The balance is protected from air currents and other hazards with a draft shield.

[0063] The weight is recorded when the balance reading becomes constant. The average weight (g) and average area (m) of the sample are recorded. 2 ) is calculated. 2 ) is the average weight (g) of the sample and the average area (m 2 ) is calculated by dividing by

[0064] "Sanitary products" as used herein refer to soft, low density (i.e., about 0.15 g / cm) wipes useful as wipes for urination and post-defecation cleaning (toilet paper), ENT delivery (facial tissue), and multi-functional absorbent and cleaning applications (absorbent towels). 3 Sanitary tissue products prepared according to the present disclosure may be subjected to any suitable post-processing, such as, but not limited to, printing, embossing, calendaring, slitting, folding, combining with other fibrous structures and / or winding.

[0065] In a preferred embodiment of the absorbent towel paper web, the fibrous structure comprises about 20% to 90% (weight percent) of a refined softwood pulp fiber blend. The long fiber softwood pulp fiber blend comprises about 18.5% to about 88.5% softwood pulp by weight of the dry fiber basis of the towel product, where the softwood pulp is optionally refined or unrefined before combining with the cationic strength polymer. The cationic strength polymer is added to the aqueous stream to allow about 0.25% to about 5.0% by weight of the polymer to be added to the papermaking furnish. After combining the softwood pulp and cationic polymer, about 0.05% to about 20% by weight of cellulose nanofilaments by weight of the dry fiber basis of the towel paper web are blended into the stream. In this embodiment of the invention, the softwood fibers, cellulose nanofilaments, and cationic flow are then blended with a 10% to 55% by weight, dry fiber basis, hardwood pulp fiber mixture of a towel product and formed into a fibrous sheet by any of the processes described above. The absorbent towel paper has a mean square tensile index of about 6 Nm / g to about 12 Nm / g, a total dry tensile strength value in the range of about 300 N / m to about 600 N / m, and a cross-grain wet tensile strength to cross-grain dry tensile strength ratio of about 0.20 to about 0.50.

[0066] Other embodiments of absorbent towel paper webs comprising cellulose nanofilaments may have a cross-grain wet tensile strength to cross-grain dry tensile strength ratio of from about 0.25 to about 0.35.

[0067] In another embodiment of the invention, a softwood fiber stream is fed into one or more separate layers of a papermaking system and separated from 10 to 55 weight percent of a hardwood pulp fiber stream. This process embodiment produces a higher strength absorbent towel web product having a mean square tensile index of about 6 Nm / g to about 12 Nm / g and a cross-grain wet tensile strength to cross-grain dry tensile strength ratio of about 0.295 to about 0.35.

[0068] The absorbent paper towel web of the present application also includes a cationic strength polymer. Generally, the cationic strength polymer may be applied in various amounts depending on the desired properties of the web. For example, in some embodiments, the total wet strength agent added may be from about 0.5 to 50 kg / T, in some embodiments, from 2 to about 15 kg / T, and in some embodiments, from about 3 to about 5 kg / T. The strength polymer may be incorporated into any layer of the multi-layer tissue web.

[0069] Optional Ingredients - Chemical Papermaking Additives: If desired, various chemical additive compositions may be optionally added to the absorbent paper towel web to further enhance consumer-desired benefits, such as softness, low lint, absorbency, and / or sheet softness. The chemical additives are selected from the group consisting of debonders, silicon softening additives, non-silicon softening additives, non-cationic strengthening additives, absorbency additives, and aesthetic additives.

[0070] Stripping agent Chemical release agents can also be applied to soften the web. Specifically, chemical release agents can reduce the amount of hydrogen bonding within one or more layers of the web, thereby resulting in a softer product. Depending on the desired properties of the resulting tissue product, the release agent can be applied in an amount of from 0% to about 3.0%, preferably from about 0.1 to about 2.0%, and more preferably from about 0.5 to about 1.0%, by weight of the dry fiber basis of the paper web. The release agent can be incorporated into any layer of a single- or multi-layer tissue web.

[0071] Suitable release agents for use as softener additives in the present invention include both cationic and non-cationic surfactants, with cationic surfactants being preferred. Non-cationic surfactants include anionic, nonionic, amphoteric, and zwitterionic surfactants. Preferably, the surfactant is substantially non-migratory in situ after the tissue paper is produced, to substantially eliminate post-production changes in the tissue paper's properties that might otherwise occur due to the inclusion of the surfactant. This can be achieved, for example, by using a surfactant with a melting temperature above temperatures normally encountered during storage, shipping, sale, and use of inventive tissue paper product embodiments, e.g., a melting temperature of about 50°C or higher.

[0072] The level of non-cationic surfactant applied to the tissue paper web to provide the softness / tensile benefits ranges from the minimum effective level required to impart such benefits on a constant tensile basis for the final product to about 2%: preferably, about 0.01% to about 2% of the non-cationic surfactant is retained by the web; more preferably, about 0.05% to about 1.0%; and most preferably, about 0.05% to about 0.3%. The surfactant preferably has an alkyl chain with 8 or more carbon atoms. Exemplary anionic surfactants are linear alkyl sulfonates and alkyl benzene sulfonates. Exemplary nonionic surfactants are alkyl glycosides, including alkyl glycoside esters such as CRODESTA® SL-40 (available from Croda, Inc. (New York, NY)); alkyl glycoside ethers as described in U.S. Pat. No. 4,011,389, issued March 8, 1977, to W.K. Langdon; alkyl polyethoxylated esters such as PEGOSPERSE® 200ML available from Glyco Chemicals, Inc. (Greenwich, Conn.); alkyl polyethoxylated ethers and esters such as NEODOLR25-12 available from Shell Chemical Co; sorbitan esters such as SPAN 60 from ICI America, Inc., ethoxylated sorbitan esters, propoxylated sorbitan esters, mixed ethoxylated propoxylated sorbitan esters, and polyethoxylated sorbitan alcohols such as TWEEN 60 (also from ICI America, Inc.). Alkyl polyglycosides are particularly preferred for use in the present invention.The above list of exemplary surfactants is intended to be merely exemplary in nature and is not meant to limit the scope of the present invention.

[0073] silicon When a chemical softener that functions primarily by imparting a smooth hand is desired, polysiloxanes or "silicones" can be used. Depending on the desired properties of the resulting tissue product, the silicon can be applied in an amount of 0% to about 3.0% by weight, preferably about 0.1 to about 2.0% by weight, and more preferably about 0.5 to about 1.0% by weight, based on the dry fiber weight of the paper web. The silicon can be incorporated into any layer of a single- or multi-layer tissue web. Silicon compounds suitable for use in the present invention are described in detail below.

[0074] The polysiloxane compound preferably has monosiloxane units of the following structure: [ka] where R1 and R2, for each individual siloxane monomer unit, can each independently be hydrogen or any alkyl, aryl, alkenyl, alkaryl, arakyl, cycloalkyl, halogenated hydrocarbon, or other radical. Any such radical can be substituted or unsubstituted. The R1 and R2 radicals of any particular monomer unit can be different from the corresponding functional group of the next adjacent monomer unit. In addition, polysiloxanes can be linear, branched, or cyclic. The R1 and R2 radicals can further independently be other silaceous functional groups, such as, but not limited to, siloxane, polysiloxane, silane, and polysilane. The R1 and R2 radicals can include any of a variety of organic functional groups, including, for example, alcohol, carboxylic acid, aldehyde, ketone, and amine, amide functional groups, with amino-functional silicone compounds being preferred. Exemplary alkyl radicals are methyl, ethyl, propyl, butyl, pentyl, hexyl, octyl, decyl, octadecyl, and the like. Exemplary alkenyl radicals are vinyl, allyl, and the like. Exemplary aryl radicals are phenyl, diphenyl, naphthyl, and the like. Exemplary alkaryl radicals are toyl, xylyl, ethylphenyl, and the like. Exemplary arakyl radicals are benzyl, α-phenylethyl, β-phenylethyl, α-phenylbutyl, and the like. Exemplary cycloalkyl radicals are cyclobutyl, cyclopentyl, cyclohexyl, and the like. Exemplary halogenated hydrocarbon radicals are chloromethyl, bromoethyl, tetrafluoroethyl, fluoroethyl, trifluoroethyl, trifluorotoyl, hexafluoroxylyl, and the like.References disclosing polysiloxanes include U.S. Pat. No. 2,826,551, issued to Geen on March 11, 1958; U.S. Pat. No. 3,964,500, issued to Drakoff on June 22, 1976; U.S. Pat. No. 4,364,837, issued to Pader on December 21, 1982; U.S. Pat. No. 5,059,282, issued to Ampulski et al. on October 22, 1991; and British Patent No. 849,433, published to Woolston on September 28, 1960. Also, Silicon Compounds, pp. 181-217, distributed by Petrarch Systems, Inc. in 1984, contains an extensive list and description of polysiloxanes in general.

[0075] strength additives The strength additive may be applied to the tissue paper web alone, simultaneously with, before, or after the addition of softening, absorbency, and / or aesthetic additives. At least an effective amount of strength additive, preferably starch, provides lint control and simultaneously increased strength upon drying compared to non-binder treatments, otherwise identical sheets are preferably applied to the sheet. Preferably, about 0.01% to about 2.0% of the strength additive, calculated on a dry fiber weight basis, is retained in the dried sheet; more preferably, about 0.1% to about 1.0% of the strength additive material, preferably starch-based, is retained.

[0076] softening additives Any surfactant other than a chemical papermaking additive emulsifying surfactant material will hereinafter be referred to as a "surfactant," and any surfactant present as an emulsifying component of an emulsified chemical papermaking additive will hereinafter be referred to as an "emulsifier." The surfactant may be applied to the tissue paper alone or simultaneously with, after, or before other chemical papermaking additives. In a typical process, the surfactant is applied to the cellulosic substrate simultaneously with the other additive(s), if other additives are present. It may also be desirable to treat the release agent-containing tissue paper with relatively low levels of binder for lint control and / or to increase tensile strength.

[0077] If a chemical emollient that functions primarily by imparting a smooth feel is desired, it can be selected from the following group of chemicals: organic materials (e.g., mineral oils or waxes, such as paraffin or carnuba, or lanolin); and polysiloxanes (e.g., compounds described in U.S. Pat. No. 5,059,282 issued to Ampulski). Polysiloxane compounds suitable for use in the present invention are described in detail below.

[0078] If a chemical emollient that functions primarily by plasticizing the structure is desired, it can be selected from the following group of chemicals: polyethylene glycol (eg, PEG 400); dimethylamine; and / or glycerin.

[0079] If a cationic chemical softener that functions primarily by exfoliation is desired, it can be selected from the following group of chemicals: cationic quaternary ammonium compounds (e.g., dihydrogenated tallow dimethylammonium methyl sulfate (DTDMAMS) or dihydrogenated tallow dimethylammonium chloride (DTDMAC), both produced by Witco Corporation of Greenwich, Conn.; Berocel 579 (manufactured by Eka Nobel of Stennungsund, Sweden); materials described in U.S. Pat. Nos. 4,351,699 and 4,447,294 issued to Osborn; and / or diester derivatives of DTDMAMS or DTDMAC). In particular, quaternary ammonium compounds having the formula: (R1) 4-m -N + -[R2] m X - m is 1 to 3; Each R1 is a C1-C8 alkyl group, a hydroxyalkyl group, a hydrocarbyl or substituted hydrocarbyl group, an alkoxylated group, a benzyl group, or a mixture thereof; each R2 is a C9-C 41an alkyl group, a hydroxyalkyl group, a hydrocarbyl or substituted hydrocarbyl group, an alkoxylated group, a benzyl group, or mixtures thereof; and X - is any softener-compatible anion. Preferably, each R2 is C 16 -C 18 alkyl, and most preferably each R2 is a straight chain C 18 Preferably, each R is methyl and X is alkyl. - is chloride or methyl sulfate. Optionally, the R2 substituent may be derived from a vegetable oil source. Biodegradable ester-functional quaternary ammonium salts having the formula: may also be used in the present invention: (R1) 4-m -N + -[(CH2) n -Y-R2] m X - Each Y=-O-(O)C-, or -C(O)-O-; m=1 to 3; preferably, m=2; each n=1 to 4; preferably, n=2; Each R1 substituent is a short chain C1-C6, preferably C1-C3, alkyl group, e.g., methyl (most preferred), ethyl, propyl, etc., hydroxyalkyl group, hydrocarbyl group, benzyl group, or mixtures thereof; each R2 is a long chain, at least partially unsaturated (IV greater than about 5 to less than about 100, preferably about 10 to about 85), C 11 -C 23 a hydrocarbyl or substituted hydrocarbyl substituent, and a counterion, X - is any softener compatible anion, such as acetate, chloride, bromide, methylsulfate, formate, sulfate, nitrate, etc. Preferably, the majority of R2 is at least 90% C 18 -C 24 More preferably, the majority of R2 is at least 90% C 18 , C 22 and mixtures thereof.

[0080] Other types of suitable quaternary ammonium compounds are described in European Patent No. 0688901A2, published December 12, 1995, assigned to Kimberly-Clark Corporation.

[0081] Tertiary amine emollient compounds may also be used in the present invention. Examples of suitable tertiary amine emollients are described in U.S. Patent No. 5,399,241, assigned to James River Corporation and issued March 21, 1995.

[0082] Absorbent additives If enhanced absorbency is desired, surfactants can be used to treat the paper web of the present invention. Surfactant levels, if used, can be, in one embodiment, from about 0.01% to about 2% by dry fiber weight of the tissue web. In one embodiment, the surfactant has an alkyl chain with 8 or more carbon atoms. Alternatively, cationic softener active ingredients with highly unsaturated (mono- and / or poly) and / or branched alkyl groups can significantly enhance absorbency.

[0083] If an absorbency aid is desired to enhance absorption, it can be selected from the following group of chemicals: polyethoxylates (e.g., PEG400); alkyl ethoxylated esters (e.g., PEGOSPERSE 200ML from Lonza Inc.); alkyl ethoxylated alcohols (e.g., Neodol); alkyl polyethoxylated nonylphenols (e.g., IGEPAL CO, produced by Rhone-Poulenc / GAF), ethoxylated trimethylpentanediol, and / or materials described in U.S. Pat. Nos. 4,959,125 and 4,940,513 issued to Spendel. In cases where the surfactant release agent softener reduces wetting, a wetting agent, such as a second surfactant, can be added to the application solution. For example, sorbitan stearate esters can be mixed with alkyl polyethoxylated alcohols to produce soft, wettable paper.

[0084] Water-soluble polyhydroxy compounds can also be used as absorption aids and / or humectants. Examples of water-soluble polyhydroxy compounds suitable for use in the present invention include glycerol, polyglycerols having a weight-average molecular weight of about 150 to about 800, and polyoxyethylenes and polyoxypropylenes having a weight-average molecular weight of about 200 to about 4000, preferably about 200 to about 1000, and most preferably about 200 to about 600. Polyoxyethylenes having a weight-average molecular weight of about 200 to about 600 are particularly preferred. Mixtures of the above polyhydroxy compounds can also be used. For example, mixtures of glycerol and polyglycerol, mixtures of glycerol and polyoxyethylene, and mixtures of polyglycerol and polyoxyethylene are useful in the present invention. A particularly preferred polyhydroxy compound is polyoxyethylene having a weight-average molecular weight of about 400. This material is commercially available from Union Carbide Company of Danbury, Conn., under the trade name "PEG-400."

[0085] If an absorption aid is desired to decrease the absorption rate, it can be selected from the following group of chemicals: alkyl ketene dimers (e.g., AQUAPELR 360XC Emulsion manufactured by Hercules Inc., Wilmington, Del.); fluorocarbons (e.g., Scotch Guard by 3M of Minneapolis, Minn.); hydrophobic silicones (e.g., PDMS DC-200 by Dow Coating of Midland, Mich.); fluorotelomers (e.g., ZONYL 7040 by DuPont of Wilmington, Del.); and the like.

[0086] The absorbent additive can be used alone or in combination with a strength additive. Starch-based strength additives have been found to be preferred binders for use in the present invention. Preferably, the tissue paper is treated with an aqueous solution of starch. In addition to reducing lint in the finished tissue paper product, low levels of starch also provide a modest improvement in the tensile strength of the tissue paper without imparting boardiness (i.e., stiffness) (which would result from the addition of high levels of starch). This also provides tissue paper with an improved strength / softness relationship compared to tissue paper strengthened by traditional methods of increasing tensile strength, such as by further refining pulp or by the addition of other dry strength additives. This result is particularly surprising because starch has traditionally been used to enhance strength at the expense of softness in applications where softness is not an important feature, such as paperboard. Additionally, starch has been used as a filler for printing and writing papers to improve surface printability.

[0087] aesthetic additives If an aesthetic additive is desired, it can be selected from the following group of chemicals: inks; dyes; fragrances; opacifiers (e.g., TiO2 or calcium carbonate), optical brighteners, and mixtures thereof. Paper aesthetics can also be improved using the process described in this invention. Inks, dyes, and / or fragrances are preferably added to an aqueous composition, which is then applied to the tissue paper web. Aesthetics target The additives may be applied alone or in combination with wetting, softening, and / or strength additives.

[0088] The paper webs of the present disclosure have high dry tensile strengths. The paper webs have a mean squared tensile in the range of about 6 Nm / g to about 12 Nm / g. Preferred embodiment paper webs have a mean squared tensile in the range of about 7 Nm / g to about 10 Nm / g. When measured separately, the paper webs of the present disclosure have a total dry tensile strength in the range of about 300 N / m to about 600 N / m for a single layer, with preferred single layer embodiments having a dry tensile strength in the range of about 350 N / m to about 500 N / m.

[0089] The single-ply paper web produced on the papermachine of the present disclosure also has a high cross-grain (CD) wet tensile strength. The paper web of the present disclosure has a cross-grain wet tensile strength to cross-grain dry tensile strength ratio in the range of about 0.20 to about 0.50 N / m, with preferred embodiments having a CD wet tensile strength to CD dry tensile strength ratio in the range of about 0.295 to about 0.35.

[0090] Manufacturing Process In Figure 1, a twin-wire former having a papermaking headbox 1 injects or deposits a furnish, an aqueous suspension of papermaking fibers, onto a plurality of forming fabrics, such as an outer forming fabric 5 and an inner forming fabric 3, thereby forming a wet tissue web 6. The forming process of the present disclosure can be any conventional forming process known in the papermaking industry, including, but not limited to, fourdrinier, roof formers, such as suction breast roll formers, and gap formers, such as twin-wire formers and crescent formers.

[0091] As the inner forming fabric 3 rotates around the forming roll 4, a wet tissue web 6 is formed on the inner forming fabric 3. The inner forming fabric 3 functions to support and transport the newly formed wet tissue web 6 downstream in the process as the wet tissue web 6 is partially dewatered to a consistency of about 10 percent based on the dry weight of the fibers. Additional dewatering of the wet tissue web 6 can be accomplished by known papermaking techniques, such as a vacuum suction box, while the inner forming fabric 3 supports the wet tissue web 6. The wet tissue web 6 can be further dewatered to a consistency of at least about 20 percent, more specifically about 20 to about 40 percent, and even more specifically about 20 to about 30 percent.

[0092] Forming fabric 3 can generally be made from a suitable porous material, such as metal wire or polymer filaments. For example, some suitable fabrics include, but are not limited to, Albany 84M and 94M, Asten 856, 866, 867, 892, 934, 939, 959, or 937, available from Albany International (Albany, NY); Asten Synweve Design 274, all available from Asten Forming Fabrics, Inc. (Appleton, Wis.); and Voith 2164, available from Voith Fabrics (Appleton, Wis.). Forming fabrics or felts including a nonwoven base layer can also be useful, including those manufactured using extruded polyurethane foams, such as the Spectra Series from Scapa Corporation.

[0093] The wet web 6 is then transferred from the forming fabric 3 to a transfer fabric 8, during which the solids concentration is about 10 to about 40 percent, specifically about 20 to about 30 percent. As used herein, a "transfer fabric" is a fabric positioned between the forming and drying sections of the web manufacturing process.

[0094] Transfer to the transfer fabric 8 can be accomplished with the aid of positive and / or negative pressure. For example, in one embodiment, a vacuum shoe 9 can apply negative pressure so that the forming fabric 3 and transfer fabric 8 simultaneously meet and diverge at the leading edge of the vacuum slot. Typically, the vacuum shoe 9 provides pressure at a level of about 10 to about 25 inches of mercury. As noted above, the vacuum transfer shoe 9 (negative pressure) can be supplemented or replaced by the use of positive pressure from the opposite side of the web, which blows the web onto the next fabric. In some embodiments, another vacuum shoe can also be used to help draw the fibrous web 6 onto the surface of the transfer fabric 8.

[0095] Typically, the transfer fabric 8 travels at a slower speed than the forming fabric 3 to enhance the web's MD and CD stretch, which generally refers to the web's stretch in its cross-grain (CD) or long-grain (MD) direction (expressed as percent elongation at specimen break). For example, the relative speed difference between the two fabrics may be from about 1 to about 30 percent, in some embodiments from about 5 to about 20 percent, and in some embodiments, from about 10 to about 15 percent. This is commonly referred to as a "rush transfer." During a "rush transfer," many of the web's bonds are believed to be broken, forcing the sheet to flex and fold into the depressions on the surface of the transfer fabric 8. Such molding to the contours of the surface of the transfer fabric 8 can increase the web's MD and CD stretch. Rush transfer from one fabric to another can follow the principles taught in any one of the following patents: U.S. Patent Nos. 5,667,636, 5,830,321, 4,440,597, 4,551,199, and 4,849,054.

[0096] The wet tissue web 6 is then transferred from the transfer fabric 8 to the through-air drying fabric 11. Typically, the transfer fabric 8 travels at approximately the same speed as the through-air drying fabric 11. However, it has now been discovered that a second rush transfer can be performed as the web is transferred from the transfer fabric 8 to the through-air drying fabric 11. This rush transfer is referred to herein as occurring at a second location and is achieved by operating the through-air drying fabric 11 at a slower speed than the transfer fabric 8. By performing rush transfers at two separate locations, i.e., a first and second location, a tissue product with increased CD stretch can be produced.

[0097] In addition to rush transferring the wet tissue web 6 from the transfer fabric 8 to the through-air drying fabric 11, the wet tissue web 6 may be macroscopically reoriented to conform to the surface of the through-air drying fabric 11 with the aid of a vacuum transfer shoe, such as vacuum transfer roll 12 or vacuum shoe 9. If desired, the through-air drying fabric 11 can be moved at a speed slower than that of the transfer fabric 8 to further enhance the MD stretch of the resulting absorbent tissue product. Transfer may also be performed with vacuum assistance to ensure conformance of the wet tissue web 6 to the topography of the through-air drying fabric 11.

[0098] While supported by the through-air drying fabric 11, the wet tissue web 6 is dried by the through-air dryer 13 to a final consistency of about 94 percent or greater. The web 15 then passes through a winding nip between a reel drum 22 and a reel 23 and is wound into a roll 25 of tissue for subsequent processing, such as slitting, folding, and packaging.

[0099] The web is transferred, preferably with the aid of a vacuum, to a through-air drying fabric for final drying, ensuring macroscopic rearrangement of the web to impart the desired bulk and appearance. The use of separate transfer and through-air drying fabrics can provide various advantages because it allows the two fabrics to be specifically designed to independently address key product requirements. For example, the transfer fabric is typically optimized to enable efficient conversion of high-lash transfer levels to high MD stretch, while the through-air drying fabric is designed to deliver bulk and CD stretch. Therefore, it is useful to have a moderately coarse, moderately three-dimensional transfer fabric and a through-air drying fabric (which in the optimized configuration is quite coarse and three-dimensional). The result is a relatively smooth sheet exiting the transfer section, which is then macroscopically rearranged (with vacuum assistance) to impart the high-bulk, high-CD stretch surface topology of the through-air drying fabric. The sheet topology changes completely from the transfer to the through-air drying fabric, and the fibers are macroscopically rearranged, including significant fiber-to-fiber movement.

[0100] The drying process can be any non-compression or compression drying method that tends to preserve the bulk or thickness of the wet web, including, but not limited to, through-air drying, infrared radiation, microwave drying, Valmet NTT, Voith ATMOS, and the like. Due to its commercial availability and practicality, through-air drying is well-known and is one commonly used means for non-compression drying of webs for purposes of this invention. Suitable through-air drying fabrics include, but are not limited to, fabrics having substantially continuous wale ridges, whereby the ridges are formed by holding together multiple warp yarns, such as those disclosed in U.S. Pat. No. 6,998,024. Other suitable through-air drying fabrics include those disclosed in U.S. Pat. No. 7,611,607, particularly the fabrics called Fred (t1207-77), Jeston (t1207-6), and Jack (t1207-12). The web is preferably dried to final dryness on the through-air drying fabric, without pressing it against the surface of a Yankee dryer, and without subsequent creping.

[0101] Once the wet tissue web 6 is uncompressed and dried, thereby forming a dry tissue web 15, the dry tissue web 15 can be creped by transferring the dry tissue web 15 to a Yankee dryer before winding, or by using an alternative shortening method, such as microcreping as disclosed in U.S. Pat. No. 4,919,877.

[0102] New Tissue Technology - NTT A paper machine 10 is shown in Figure 2. The paper machine includes a wet section or forming section 20, a press section 30, and a dryer section 50. The wet section 20 includes a headbox 22, forming rolls 23, an endless inner fabric 24, and an endless outer fabric 25 comprised of a forming wire. The inner and outer fabrics 24 and 25, respectively, run in separate loops around a number of guide rolls 26 and 27.

[0103] The drying section 50 includes a heated drying cylinder 52, which is covered by a hood 54. The drying cylinder and hood may collectively comprise a Yankee dryer. At the exit side of the drying section, a creping doctor 56 is arranged to crepe the fibrous web exiting the drying cylinder 52. An applicator device 58 is provided for applying a suitable adhesive or other composition onto the outer surface of the drying cylinder 52. The resulting creped web is then rolled onto a parent roll (not shown) for subsequent conversion into the desired final product form.

[0104] The press section 30 includes at least one press having two cooperating first and second press members 31 and 32, which together define a press nip. The press section further includes an endless press felt 33 looped around the first press member 31 and guide rolls 34, and an endless impermeable transfer belt 35. The transfer belt 35 looped around the second press member 32 and a plurality of guide rolls 36. A suction roll (not numbered) is also shown in FIG. 1 upstream of the press nip, within the loop of felt 33 where the felt 33 overlaps the inner fabric 24. This suction roll dewaters the felt 33 and the paper web prior to the press nip. For example, the suction roll can be operated at a vacuum of about 40 kPa, which allows the paper web entering the press nip to have a dry solids content of about 15% to 20%.

[0105] 2, the press is a shoe press, where the first press member includes a shoe press roll 31 and the second press member includes an opposing roll 32. The shoe press roll and the opposing roll define a press nip extending therebetween. Other types of presses can be used in place of a shoe press.

[0106] The papermaking machine further includes a permeable final fabric 37 arranged to move in a loop around a suction transfer device 38 positioned adjacent to the transfer belt 35 to define a transfer point 40 for transfer of the paper web from the transfer belt 35 to the final fabric 37. The transfer point 40 is located a distance D from the press nip, measured along the path traversed by the transfer belt 35. The suction transfer device 38 forms a suction zone 41 operable to apply suction through the final fabric 37 to transfer the paper web from the transfer belt 35 onto the final fabric 37. When producing a structured tissue web, the final fabric includes a structured fabric (or "texturizing fabric") having a structured surface, and the suction applied by the suction transfer device 38 further functions to mold the wet tissue web onto the structured surface of the fabric. The "structured fabric" may have no more than about 25 wale-oriented knuckles or other raised surface features per square centimeter. The fabric 37 moves around a transfer roll 39 which defines with the dryer cylinder 52 a non-compressed nip for transfer of the tissue web from the fabric 37 onto the dryer cylinder 52 .

[0107] 1, the suction transfer device 38 is a suction roll having a suction zone 41 encompassing a predetermined sector angle. The transfer belt 35 is arranged to partially cover the curved outer surface of the suction device 38. As an alternative to a roll, the suction transfer device may be another type of suction device, for example a suction shoe having a curved outer surface, or a suction box having a non-curved suction surface of a defined length L.

[0108] The characteristics of the transfer belt 35 and its arrangement in relation to the structured fabric 37 and suction transfer device 38 are particularly important for the production of low-basis-weight tissue webs, such as those having a basis weight of about 20 grams per square meter (gsm) or less, more specifically about 10 to about 20 gsm, and even more specifically about 10 to about 15 gsm. As used herein, "basis weight" refers to the amount of oven-dry fiber in the web while it is being placed on the dryer cylinder 52 during the tissue-making process. This should be distinguished from the "finished" basis weight, which may be affected by the presence of crepe pleats that shorten the web along the length. However, the basis weight of a tissue web on the dryer can be closely estimated from the finished basis weight by measuring the basis weight of the tissue web after all of the length shortening has been removed. Tissue webs with such low basis weights are particularly difficult to handle on a paper machine because wet tissue webs have virtually no tensile strength. As a result, the process of separating the tissue web from the transfer belt 35 and transferring it onto the structured fabric 37 is complicated by the very low strength of the web.

[0109] More specifically, when the transfer belt 35 with the tissue web thereon exits the press nip formed by the press members 31 and 32, a thin film of water exists between the tissue web and the surface of the transfer belt 35. It is theorized that as long as this water film remains intact, the tissue web cannot be separated from the transfer belt without significant risk of web rupture. From multiple tests of transfer belts with different properties, it has been found that the surface characteristics of the transfer belt play a significant role in determining whether the tissue web can be separated from the transfer belt. Specifically, it has been found that some types of transfer belts make it difficult or essentially impossible to separate the tissue web, while other types of transfer belts allow the tissue web to be separated (as long as other criteria, as further explained below, are also met). Based on these tests, it is theorized that transfer belts that allow the web to separate are able to cause the thin water film to dissipate or break down after a certain period of time has passed since the web exited the press nip, while transfer belts that do not allow the web to separate without breaking down do not allow the water film to dissipate.

[0110] In view of the test results, it has been found that a paper machine for producing a tissue web with a low basis weight (as previously mentioned), such as that illustrated in FIG. 1, can be used as long as the transfer belt 35 has the proper surface characteristics to dissipate the water film, and as long as there is a sufficient period of time (referred to herein as "dwell time," td) for the water film to dissipate. The dwell time is the period of time it takes the web to travel the distance D from the press nip to the transfer point 40. The dwell time (seconds) can be calculated using the formula td=(D / V) * 60 is related to the speed V (meters / minute) of the transfer belt 35. Thus, for example, if V=1000 m / minute and D=4 m, td is equal to 0.24 seconds.

[0111] With regard to the surface characteristics of the transfer belt 35, it has been found that transfer belts whose web-contacting surfaces are formed with a substantially non-porous polymer coating and which may have a polished or sanded surface to increase their surface roughness to an arithmetic mean roughness of about Ra=2-5 μm generally do not cause the tissue web to separate from the transfer belt, even when the distance D is made long enough to provide a dwell time td of at least 0.5 seconds. It should be noted that for reasons of machine compactness, it is usually desirable to keep the distance D as small as possible while still ensuring that the tissue web transfer occurs without destroying the web. Thus, based on the tests conducted, it has been determined that transfer belts having a substantially non-porous polymer coating cannot be used, even if they are sanded to increase their surface roughness.

[0112] Advanced tissue molding system - ATMOS The matters shown in this specification are exemplary and are merely for the purpose of illustratively describing embodiments of the present invention, and are presented to provide what is believed to be the most useful and easily understood explanation of the principles and conceptual aspects of the present invention. In this regard, no attempt is made to show the structural details of the present invention in more detail than is necessary for a basic understanding of the present invention, and a description is provided together with the drawings that will make clear to those skilled in the art how the forms of the present invention can be actually embodied.

[0113] Referring now to FIG. 3, a machine TWA for producing a fibrous web W, such as tissue, sanitary paper web, etc., is shown, which may be, for example, a twin-wire ATMOS system for processing the fibrous web W. The system TWA includes a headbox 1 that delivers a suspension to a twin-wire former formed by an outer wire 3a, an inner wire 3b, and a forming roll 2. The twin-wire former may be of any conventional, known type, preferably the type disclosed in U.S. patent application Ser. No. 11 / 189,884, filed July 27, 2005. Once the web W is formed by the twin-wire former, the inner wire 3b transports the web W to a structured fabric 4. The web W is transferred from the inner wire 3b to the structured fabric 4 using a suction box 5 located in the pickup area. The web W is transported by the structured fabric 4 to and through a press arrangement formed by a belt press assembly 18 consisting of a permeable tension belt 12 and a vacuum roll 9. The dewatering fabric 7 also passes over vacuum roll 9 through belt press assembly 18. The web W is dewatered in the extended belt press nip formed by belt press assembly 18 and vacuum roll 9, conveyed by structured belt 4 to Yankee cylinder 15 and hood 16 arrangement, and transferred to Yankee 15 using press roll 14. A steam box and hot air blower arrangement 11 is arranged within permeable tension belt 12 and arranged above suction zone Z of vacuum roll 9. One or more savealls 10 are used to collect moisture collected from vacuum roll 9. The system also uses multiple guide rolls for each of the belts / fabrics, an adjustment roll 19 for dewatering belt 7, multiple Uhle boxes 6a and 6b, multiple shower units 8a, 8b, 8c, and 8d, and additional suction boxes or pickups 13.

[0114] By way of non-limiting example, the outer wire 3a may be a conventional endless circulating wire and / or may be a DSP belt (e.g., of the type disclosed in U.S. Pat. No. 6,237,644). The outer wire 3a may also be any suitable conventional wire.

[0115] As a non-limiting example, the inner wire 3b may be an endless circulating belt. The inner wire 3b may also be any suitable conventional wire.

[0116] By way of non-limiting example, forming roll 2 may be a solid roll or an open roll. Roll 2 may also be any suitable conventional forming roll.

[0117] As a non-limiting example, the belt press belt 12 may be a belt of the type disclosed in U.S. Patent Application No. 11 / 276,789, filed March 14, 2006. By way of example, the permeable belt 12 may have a side facing the paper web, be guided over the support surface of the roll 9, and have the following characteristics: a tension of about 20 kN / m to about 100 kN / m, a permeability value of about 100 cfm to about 1200 cfm, a surface contact area of ​​the paper web side when not under tension of about 0.5% to about 90%, and an open area of ​​about 1.0% to about 85%.

[0118] For example, the permeable belt 12 may preferably have the following properties: the belt 12 must be able to withstand high MD (machine direction) tension for extended periods without stretching and without distortion of the monofilaments; the belt 12 must be able to withstand the effects of steam (and superheated steam) from the steam box in an ATMOS configuration, i.e., it must be resistant to hydrolysis; the belt 12 must be able to pass a sufficient volume of air through the paper sheet so that a sufficient dryness (approximately 32" to approximately 35% or more) is achieved after the belt press when the web passes to final drying in the Yankee drying and creping stages. The belt 12 should preferably have suitable permeability and surface contact area, materials, and weaves as described herein; and the belt 12 should be part of a system or process that is an efficient and economical manner of drying tissue. The belt 12 may also be a belt press belt of the type disclosed in U.S. application Ser. No. 10 / 972,408, filed Oct. 26, 2004, and / or U.S. application Ser. No. 10 / 972,431, filed Oct. 26, 2004, and / or U.S. application Ser. No. 10 / 768,485, filed Jan. 30, 2004.

[0119] By way of non-limiting example, dewatering fabric 7 may be, for example, a dewatering fabric of the type disclosed in U.S. patent application Ser. No. 11 / 380,835, filed Apr. 28, 2006, and may have the following characteristics and properties: By way of example, dewatering fabric 7 may have a side facing the paper web, may be guided over a support surface, such as the support surface of roll 9, and may have the following properties: a caliper of approximately 0.1 mm to approximately 15 mm, a permeability value of approximately 1 cfm to approximately 500 cfm, an overall density of approximately 0.2 g / cm3 to approximately 1.10 g / cm3, and a weight of approximately 350 g / m2 to approximately 3000 g / m2. The caliper may also preferably be from about 2 mm to about 4 mm, the permeability value may preferably be from about 10 cfm to about 50 cfm, the overall density may preferably be from about 0.2 g / cm to about 1.10 g / cm, and the weight may preferably be from about 900 g / m to about 1300 g / m. The dewatering fabric 7 should also preferably have good compressibility.

[0120] According to one non-limiting embodiment of the invention, the formed web W is transferred to the structured fabric 4 using suction boxes 5. This occurs while the structured fabric 4 and the inner wire 3b travel at different speeds; i.e., a speed differential between the belts 3b and 4 is used. Preferably, the structured belt 4 travels at a slower speed than the inner wire 3b. The web W travels longitudinally past the first suction box 5a and the second suction box 5b. Using the vacuum boxes 5a and 5b, sufficient moisture can be removed from the web W to achieve a solids level of approximately 7% to approximately 25% at a typical or nominal 20 grams per square meter (gsm) web travel. The vacuum at the boxes 5 can provide a vacuum of approximately -0.2 to approximately -0.8 bar, with a preferred operating level of approximately -0.4 to approximately -0.6 bar. As the fibrous web W travels along the longitudinal direction m, it contacts the dewatering fabric 7. The dewatering fabric 7 can be an endless, circulating belt, guided by multiple guide rolls. The tension of the fabric 7 can be adjusted by adjusting the guide rolls 19. The dewatering belt 7 can be a dewatering fabric or a felt. The web W then advances toward the vacuum roll 9 between the structured fabric 4 and the dewatering fabric 7. The vacuum roll 9 rotates along the machine direction m and can be operated at a vacuum level of approximately -0.2 to approximately -0.8 bar, with a preferred operating level of at least approximately -0.4 bar, and most preferably approximately -0.6 bar. By way of non-limiting example, the thickness of the vacuum roll shell of the roll 9 can range from approximately 25 mm to approximately 75 mm. The average airflow through the web W in the area of ​​the suction zone Z can be approximately 150 m3 / min / meter of machine width at atmospheric pressure and ambient temperature. The structured fabric 4, web W, and dewatering fabric 7 are guided through the belt press 18 formed by the vacuum roll 9 and the permeable belt 12. As shown in the figure, the permeable belt 12 is a single, endless, circulating belt that is guided by multiple guide rolls and presses against the vacuum roll 9, forming the belt press 18.

[0121] The upper or structured fabric 4 is an endless fabric that transports the web W to and from the belt press system 18, through the twin-wire formers 2 / 3a / 3b, and onto the Yankee cylinder 15 for final drying. After being transferred from the twin-wire formers, the web W exists in the three-dimensional structure of the upper fabric 4, so that it is not flat but also has a three-dimensional structure, which produces a bulky web. The lower fabric 7 is also permeable. The lower fabric 7 is designed to be able to store water. The lower fabric 7 may also have a smooth surface. The lower fabric 7 may preferably be a felt with a batt layer. The diameter of the batt fibers in the lower fabric 7 may be equal to or less than approximately 11 dtex, preferably equal to or less than approximately 4.2 dtex, and more preferably equal to or less than approximately 3.3 dtex. The batt fiber may also be a blend of fibers. The lower fabric 7 may also include a vector layer containing fibers from approximately 67 dtex, and may also contain even coarser fibers, such as approximately 100 dtex, approximately 140 dtex, or even higher dtex numbers. This is important for good water absorption. The wetted surface of the batt layer of the lower fabric 7 and / or the lower fabric itself may be approximately 35 m² / m² of felt area or more, preferably approximately 65 m² / m² of felt area or more, and most preferably approximately 100 m² / m² of felt area or more. The specific surface of the lower fabric 7 may be approximately 0.04 m² / g of felt weight or more, preferably approximately 0.065 m² / g of felt weight or more, and most preferably approximately 0.075 m² / g of felt weight or more. This is also important for good water absorption. Dynamic stiffness K as a value for compressibility *A compressibility of 100,000 N / mm or less is acceptable, with a preferred compressibility of 90,000 N / mm or less, and most preferably a compressibility of 70,000 N / mm or less. The compressibility (thickness change with force expressed in mm / N) of the lower fabric 7 should be taken into consideration. This is important for efficiently dewatering the web to a high dryness level. A hard surface will not press the web W between the protruding points of the structured surface of the upper fabric 4. On the other hand, the felt should not be pressed too deeply into the three-dimensional structure to avoid loss of bulk and therefore quality, e.g., water retention capacity.

[0122] Also, by way of non-limiting example, the permeable belt 12 may be a single- or multi-layer woven fabric capable of withstanding high running tensions, high pressures, heat, and moisture concentrations to achieve the high levels of water removal required by the papermaking process. The fabric 12 preferably has high width stability and must be able to operate at high running tensions, e.g., from approximately 20 kN / m to approximately 100 kN / m, preferably above approximately 20 kN / m and below approximately 60 kN / m. The fabric 12 should also preferably have suitable high permeability and may be made of hydrolysis- and / or heat-resistant materials. The permeable high-tension belt 12 forms part of a "sandwich" structure including the structured belt 4 and the dewatering belt 7. These belts 4 and 7, along with the web W disposed therebetween, are subjected to pressure in a press apparatus 18 including the high-tension belt 12 arranged on a rotating roll 9. In other embodiments, the belt press 18 can be used in an apparatus that utilizes a static extended dewatering nip instead of the rotating roll 9.

[0123] Returning to the drawings, the nip formed by belt presses 18 and 9 may have a contact angle of approximately 30° to 180°, preferably approximately 50° to approximately 140°. As a non-limiting example, the nip length may be approximately 800 mm to approximately 2500 mm, preferably approximately 1200 mm to approximately 1500 mm. Also, as a non-limiting example, the diameter of suction roll 418 may be approximately 1000 mm to approximately 2500 mm or more, preferably approximately 1400 mm to approximately 1700 mm.

[0124] To allow for suitable dewatering, the single-layer or multi-layer fabric 12 should preferably have a permeability value of approximately 100 cfm to approximately 1200 cfm, and most preferably approximately 300 cfm to approximately 800 cfm. The nip may also have a contact angle that is preferably between 50° and 130°. The single-layer or multi-layer fabric or permeable belt 12 may also be a pre-formed endless woven belt (i.e., a pre-connected or sewn belt). Alternatively, the belt 12 may be a woven belt with its ends connected together via pin-seams, or alternatively, may be sewn on a machine. The single-layer or multi-layer fabric or permeable belt 12 may also preferably have a paper surface contact area of ​​approximately 0.5% to approximately 90% when not under pressure or tension. The contact surface of the belt 12 should not be altered by subjecting the belt to sanding or abrasion. As a non-limiting example, the belt 12 should have an open area of ​​approximately 1.0% to approximately 85%. The single or multi-layer fabric or permeable belt 12 may also be a woven belt having a paper surface warp count of 5 yarns / cm to approximately 60 yarns / cm, preferably approximately 8 yarns / cm to approximately 20 yarns / cm, and most preferably approximately 10 yarns / cm to approximately 15 yarns / cm. Additionally, the woven belt 12 may have a paper surface weft count of approximately 5 yarns / cm to approximately 60 yarns / cm, preferably approximately 5 yarns / cm to approximately 20 yarns / cm, and most preferably approximately 8 yarns / cm to approximately 17 yarns / cm.

[0125] Due to the high moisture and heat that can be generated in the ATMOS papermaking process, the woven single or multi-layer fabric or permeable belt 12 may be made of one or more hydrolysis- and / or heat-resistant materials. The one or more hydrolysis-resistant materials may preferably be PET monofilament, ideally having an intrinsic viscosity value typically associated with dryer and TAD fabrics, i.e., in the range of 0.72 IV to 1.0 IV. These materials may also have a suitable "stabilization package," including carboxyl end-group equivalents. When considering hydrolysis resistance, consideration must be given to carboxyl end-group equivalents (because acid groups catalyze hydrolysis) and residual DEG or diethylene glycol (which can also increase the rate of hydrolysis). These factors separate the resin from typical PET bottle resins. For hydrolysis resistance, carboxyl equivalents should initially be as low as possible, and it has been found that they should be less than 12. DEG levels of less than 0.75% should preferably be used. Even at this low level of carboxyl end-groups, it is essential that an end-capping agent be added. To ensure that there are no free carboxyl groups at the end of the process, carbodiimides should be used during extrusion. There are several classes of chemicals that can be used to cap the end groups, such as epoxies, ortho-esters, and isocyanates, but in practice, the combination of monomeric carbodiimides and monomeric polymeric carbodiimides is the best and most used. Preferably, all end groups are capped with an end-capping agent that can be selected from the above classes so that there are no free carboxyl end groups.

[0126] PPS can be used for heat resistant materials. Other single polymer materials, such as PEN, PBT, PEEK, and PA, can also be used to improve properties such as stability, cleanliness, and lifespan. Both single polymer and copolymer yarns can be used.

[0127] The material used for the high tensile belt 12 does not necessarily have to be made from monofilament, but may be multifilament, including sheath-core. Other materials, such as non-plastic materials, may also be used, such as metallic materials.

[0128] The permeable belt 12 need not be made of a single material; it may also be made of two, three, or more different materials, i.e., the belt may be a composite belt. The permeable belt 12 may also be formed with an outer layer, coating, and / or treatment that is a polymeric material that may be applied by deposition and / or crosslinked during processing. Preferably, the coating enhances fabric stability, stain resistance, drainage, abrasion, improved heat resistance, and / or hydrolysis resistance. It is also preferred if the coating reduces fabric surface tension to aid sheet release or reduce drive load. The treatment or coating may be applied to impart and / or improve one or more of these properties.

[0129] The permeable belt 12 does not necessarily require a superior contact area; i.e., one non-limiting example of a belt 12 that works well in an ATMOS system includes a contact area of ​​less than 10%. Ideally, the permeable belt 12 has suitable permeability and surface contact area. The belt material and weave are less important than such considerations.

[0130] As a non-limiting example, structured fabric 4 may be a structured fabric of the type disclosed in U.S. Patent Application No. 11 / 380,826, filed April 28, 2006. By way of example, structured fabric 4 may have a side facing the paper web, may be guided over the support surface of roll 9, and may have the following properties: a permeability value of approximately 100 cfm to approximately 1200 cfm, a paper surface contact area of ​​approximately 5% to approximately 70% when not under pressure and tension, and an open area of ​​approximately 10% to approximately 90%.

[0131] Also, by way of non-limiting example, structured fabric 4 may be a single-layer or multi-layer woven fabric that can withstand high pressure, heat, and moisture concentration, achieve high levels of water removal, and mold or emboss the paper web required by the Voith ATMOS papermaking process. Fabric 4 should also have width stability, suitably high permeability, and preferably utilize hydrolysis- and / or heat-resistant materials.

[0132] Fabric 4 is used as part of a sandwich structure containing at least two other belts and / or fabrics. These additional belts include high-tension belt 12 and dewatering belt 7. The sandwich structure is subjected to pressure and tension over an extended nip formed by rotating roll 9 or a static support surface. The extended nip may have a contact angle of approximately 30° to approximately 180°, preferably approximately 50° to approximately 130°. The nip length can be approximately 800 mm to approximately 2500 mm, preferably approximately 1200 mm to approximately 1500 mm. The nip may be formed by a rotating suction roll having a diameter of approximately 1000 mm to approximately 2500 mm, preferably approximately 1400 mm to approximately 1700 mm.

[0133] The structured fabric 4 imparts a topographical pattern to the paper sheet or web. To accomplish this, high pressure is applied to the forming fabric 4 via the high-tension belt 12. The topography of the sheet pattern can be manipulated by varying the specifications of the forming belt 4, i.e., by adjusting parameters such as yarn diameter, yarn shape, yarn density, and yarn type. Different topographical patterns can be imparted in the sheet by different surface weaves. Similarly, the intensity of the sheet pattern can be varied by varying the specifications of the forming belt 4 by changing the pressure applied by the high-tension belt 12. Other factors that can affect the nature and intensity of the topographical pattern in the sheet include air temperature, air velocity, air pressure, belt residence time in the extended nip, and nip length.

[0134] The following are non-limiting characteristics and / or properties of the structured fabric 4: to allow for suitable dewatering, the single or multi-layer fabric should have a permeability value of approximately 100 cfm to approximately 1200 cfm, preferably approximately 200 cfm to approximately 900 cfm; fabric 4, which is part of a sandwich structure with two other belts, such as high-tension belt 12 and dewatering belt 7, is subjected to pressure and tension on a rotating or static support surface with a contact angle of approximately 30° to approximately 180°, and preferably approximately 50° to approximately 130°; fabric 4 should have a paper surface contact area of ​​approximately 5% to approximately 70% when not under pressure or tension; forming fabrics should have an open area of ​​approximately 10% to approximately 90%. Fabric 4 is preferably a woven fabric that can be placed on an ATMOS machine as a pre-connected and / or seamed continuous and / or endless belt. Alternatively, the forming fabric 4 may be joined on the ATMOS machine, for example, using a pin-seam arrangement, or otherwise sewn on the machine. To resist the high moisture and heat generated by the ATMOS papermaking process, the woven single or multi-layer belt 4 may utilize either hydrolysis-resistant and / or heat-resistant materials. The hydrolysis-resistant material should preferably comprise PET monofilaments with an intrinsic viscosity value typically associated with dryer and TAD fabrics, ranging from 0.72 IV to approximately 1.0 IV, and should also have a suitable "stabilization package" including carboxyl end-group equivalents (because acid groups catalyze hydrolysis) and residual DEG or diethylene glycol (because this also increases the rate of hydrolysis). These two factors separate a usable resin from typical PET bottle resins. For hydrolysis, the carboxyl equivalent should initially be as low as possible, found to be less than approximately 12. The DEG level should be less than approximately 0.75%.Even with this low level of carboxyl end groups, it is essential that an end-capping agent be added, and a carbodiimide should be used during extrusion to ensure that there are no free carboxyl groups at the end of the process. There are several classes of chemicals that can be used to cap the end groups, such as epoxies, ortho-esters, and isocyanates, but in practice, monomeric carbodiimides and their combination with monomeric polymeric carbodiimides are the best and most used.

[0135] Heat-resistant materials such as PPS can be used in the structured fabric 4. Other materials, such as PEN, PBT, PEEK, and PA, can also be used to improve the properties of the fabric 4, such as stability, cleanliness, and lifespan. Both single-polymer and copolymer yarns can be used. The material for the belt 4 does not necessarily have to be made of monofilament; it can be multifilament, sheath-core, or non-plastic, i.e., metallic. Similarly, the fabric 4 does not necessarily have to be made of a single material; it can be made of two, three, or more different materials. Shaped yarns, i.e., non-circular yarns, can also be used to enhance or control the topography or properties of the paper sheet. Shaped yarns can also be used to improve or control fabric characteristics or properties, such as stability, caliper, surface contact area, surface flatness, permeability, and abrasion.

[0136] The structured fabric 4 may also be treated and / or coated with additional polymeric materials, for example, applied by deposition. Materials may be added and crosslinked during processing to enhance fabric stability, stain resistance, drainage, abrasion, improve heat and / or hydrolysis resistance, and reduce fabric surface tension. This aids sheet release and / or reduces drive loads. Treatments / coatings can be applied to impart / improve one or several of these properties of the fabric 4. As previously indicated, the topographical pattern in the paper web W can be varied and manipulated through the use of different single and multi-layer weaves. Further pattern enhancement can be achieved by tailoring to a particular fabric weave, such as by changes to yarn diameter, yarn count, yarn type, yarn shape, permeability, caliper, and the addition of treatments or coatings. Finally, one or more surfaces of the fabric or forming belt 4 may be subjected to sanding and / or polishing to enhance surface properties.

[0137] It is understood that the foregoing examples are provided for illustrative purposes only and are not to be construed as limiting the invention in any way. While the invention has been described with reference to exemplary embodiments, it is understood that the terms used are terms of description and illustration, rather than of limitation. Changes may be made in this respect, within the scope of the appended claims, as herein stated and as amended, without departing from the scope and spirit of the invention. While the invention has been described herein with reference to particular sequences, materials, and embodiments, it is not intended that the invention be limited to the particulars disclosed herein. Instead, the invention extends to all functionally equivalent structures, methods, and uses, as fall within the scope of the appended claims.

[0138] Non-creped through-air dried - UCTAD A method of carrying out this invention will now be described in more detail with reference to Figure 4. Figure 4 describes a process for producing an uncreped, through-air-dried basesheet suitable for offline application of a heating composition. A twin-wire former is shown having a layered papermaking headbox 1 in which an aqueous suspension of papermaking fibers is poured or deposited onto a forming fabric 2. The web is then transferred to fabric 4, which serves to support and transport the newly formed wet web downstream in the process while the web is partially dewatered to a consistency of about 10 dry weight percent. Additional dewatering of the wet web can be accomplished, for example, by vacuum suction while the wet web is supported by the forming fabric.

[0139] The wet web is then transferred from the forming fabric to a transfer fabric 6, traveling at a slower speed than the forming fabric, to impart increased MD stretch to the web. A kiss transfer is preferably performed with the aid of a vacuum shoe 5 to avoid compressing the wet web. The web is then transferred from the transfer fabric to a through-air drying fabric 8 with the aid of a vacuum transfer roll 7 or vacuum transfer shoe. The through-air drying fabric can travel at approximately the same speed or a different speed than the transfer fabric. If desired, the through-air drying fabric moves at a slower speed to further enhance MD stretch. Transfer is preferably performed with vacuum assistance to ensure deformation of the sheet to the through-air drying fabric, thereby providing the desired bulk, softness, CD stretch, and appearance.

[0140] The level of vacuum used for web transfer may be about 3 to about 15 inches of mercury (75 to about 380 mm of mercury), preferably about 10 inches of mercury (254 mm). The vacuum shoe (negative pressure) may be supplemented or replaced by the use of positive pressure from the opposite side of the web to blow the web onto the next fabric in addition to or instead of sucking it onto the next fabric by vacuum. Also, one or more vacuum rolls may be used to replace the vacuum shoe(s).

[0141] While supported by the through-air drying fabric, the web is final dried by the through-air dryer 9 to a consistency of about 94 percent or greater and then transferred to an upper carrier fabric 11 .

[0142] The dry base sheet 13 is transported between upper and lower transfer fabrics, 11 and 12, respectively, to reel 14 where it is wound onto roll 15 for subsequent printing of the heated composition and further processing.

[0143] Example Example 1: Absorbent terry cloth Absorbent towel paper webs were produced on a through-air drying tissue making paper machine or "Valmet Karlstad TAD" demonstrator machine equipped with: Forming wire: Microline XP or similar and equivalent Thinline Q592, TAD fabric: Prolux 593 or equivalent homogeneous sheet, Chemistry: PAE / CMC pH approx. 8-9 ratio 3-4 / 1, Purification of only long fibers. Target: approx. 550 CSF. Northern Softwood Craft: Mercer Celgar NBSK ("BNSK") Hardwood Craft: Eucalyptus: Brazilian ("BEuc") Cellulose nanofilament: supplied by Kruger Canada Target Characteristics: High and mid-rise US terry cloth: Weight: 52GSM Total tensile strength: 460-740 (N / m) CD tensile: 130-270 (N / m) MD tensile: 230-470 (N / m) Tensile GMT 6.5-11Nm / g Total wet tensile: 100-160 (N / m) CD wet tensile: 30-60 (N / m) MD wet tensile: 45-100 (N / m) Furnish content: BNSK 55% BEuc 45% Cellulose nanofilaments are added to the BNSK stream as a BNSK substitute

[0144] Part 1: Towel format. The process was kept constant with the only change being the addition of cellulose nanofilament material at 2.5 and 5.0%. The table below shows the results: [Table 1]

[0145] Observation: Holding papermaking variables constant, the addition of CF predictably increases the dry tensile from 173 to 239 N / M at the conditions listed above, but surprisingly increases the wet-to-dry tensile ratio from 0.29 to 0.34. This data was unexpected from all previous information disclosed related to CF fibers.

[0146] Part 2: Towel format reel data using refinement as a control knob to keep the product constant at roughly the same total tensile value and on target. [Table 2]

[0147] Observations: We were not successful in holding product tensiles constant within product groups using refining alone as a control knob within the time constraints of this experiment. While CD tensiles were held constant within the range of 162-166 N / m only within the process and test method variations, surprisingly, CD wet tensiles increased from 45 to 52.8 N / m, which surprisingly increased the wet-to-dry tensile ratio from 0.28 to 0.32. Even more surprising was the fact that wet tensiles increased as refining energy input was reduced, since it is well documented that wet tensiles generally increase with refining over standard refining control limits. This data was unexpected from all previous information disclosed related to cellulose filament fibers.

[0148] Analytical Test Methods The following test methods are representative of techniques used to determine the physical properties of the absorbent paper webs involved herein.

[0149] 1. Sample Conditioning and Preparation All samples for testing are generally prepared in a conditioning environment that conforms to accepted standards for paper testing. The conditioning environment for the samples has a constant humidity of approximately 50% and a temperature of approximately 74 degrees Fahrenheit.

[0150] 2. Total dry tensile strength The dry tensile strength properties of absorbent paper web samples of the present invention are determined by performing the test methods published by the International Organization for Standardization, ISO 12625-4:2005, Tissue Paper and Tissue Products - Part 4: Determination of Tensile Strength, Stretch at Break, and Tensile Energy Absorption. ISO 12625-4 is used to measure both length-of-grain (MD) and cross-grain (CD) dry tensile strengths. The total dry tensile strength is the mathematical sum of the length-of-grain dry tensile strength and the cross-grain dry tensile strength.

[0151] 3. Mean square dry tensile strength The mean square dry tensile strength index is a calculated parameter derived from ISO 12625-4 results and is equal to the square root of the MD tensile index squared plus the CD tensile index squared. The mean square dry tensile may provide a more representative metric for assessing overall sheet strength per unit mass.

[0152] 4.Wet tensile strength The wet tensile strength properties of absorbent paper web samples of the present invention are determined by performing the test method published by the International Organization for Standardization, ISO 12625-5:2005, Tissue Paper and Tissue Products - Part 5: Determination of Wet Tensile Strength. ISO 12625-5 is used to measure both machine-wise (MD) and cross-machine (CD) wet tensile strength.

[0153] 5. CD wet tensile:CD dry tensile ratio The characteristic ratio of grain wet tensile strength to grain dry tensile strength is calculated as the mathematical ratio of two characteristic parameters. ratio= CD wet tensile strength CD dry tensile strength

[0154] As used in this disclosure, the terms "comprises," "comprising," and other derivatives of the root term "comprises" are intended to be open-ended terms specifying the presence of any stated features, elements, integers, steps, or components, and are not intended to exclude the presence or addition of one or more other features, elements, integers, steps, components, or groups thereof.

[0155] The dimensions and values ​​disclosed herein should not be understood to be strictly limited to the exact dimensions and values ​​recited. Instead, unless otherwise specified, each such dimension and / or value is intended to mean both the recited dimension and / or value and a functionally equivalent range surrounding that dimension and / or value. For example, a dimension disclosed as "40 mm" is intended to mean "about 40 mm."

[0156] While particular embodiments of the present invention have been illustrated and described, it would be obvious to those skilled in the art that various other changes and modifications can be made without departing from the spirit and scope of the invention. Therefore, it is intended in the appended claims to cover all such changes and modifications that are within the scope of this invention.

Claims

1. An absorbent towel paper web having a longitudinal grain and a cross grain perpendicular to the longitudinal grain, the absorbent towel paper web comprising: (a) 40% to 90%, by weight, of the absorbent towel paper web dry fiber basis, of a refined softwood pulp fiber blend comprising: i) 18.5% to 88.5% softwood pulp fibers, by weight, on a dry fiber basis of the absorbent towel paper web; ii) 0.25% to 5.0% by weight of a cationic strengthening polymer, based on the dry fiber of the absorbent towel paper web; and iii) 0.05% to 20% by weight of cellulose nanofilaments, based on the dry fiber weight of the absorbent towel paper web, the cellulose nanofilaments having an average width of 30 nm to 500 nm and an aspect ratio of 200 to 5000; a softwood pulp fiber mixture comprising: (b) 10% to 60% by weight of a hardwood pulp fiber blend, based on the dry fiber weight of the absorbent towel paper web; and (c) 10% by weight or less of moisture; Including, the softwood pulp fiber mixture, the hardwood pulp fiber mixture, and the moisture total 100% by weight of the absorbent towel paper web on a dry fiber basis; the absorbent towel paper web has a total dry tensile strength value in the range of 300 N / m to 498 N / m; The absorbent towel paper web has a cross-grain wet tensile strength to cross-grain dry tensile strength ratio value in the range of 0.20 to 0.

34. Absorbent towel paper web.

2. 10. The absorbent towel paper web of claim 1, further characterized in that the absorbent towel paper web is a differential density absorbent towel paper web.

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