# Patent

## Title
High softness, high durability bath tissues with temporary wet strength

## Abstract

A multi-ply bath tissue having no more than three plies and no fewer than two plies. The multi-ply tissue has a basis weight of from about 20 to about 35 lbs per 3000 sq foot ream and includes from about 3% to about 50% cellulosic microfiber, from about 50% to about 97% wood pulp fibers, has a geometric mean (GM) dry tensile of from about 17 to 80 g/3 in. per pound of basis weight, a cross-machine direction (CD) dry tensile of between about 30 to about 60 g/3 in. per pound of basis weight, and sufficient temporary wet strength resin to provide an initial Finch Cup CD wet tensile of from about 2.5 to about 20 g/3 in. per pound of basis weight. The initial Finch Cup CD wet tensile decays to less than 65% of the initial value in less than fifteen minutes after immersion in water. The product has a caliper of at least 5 mils per 8 sheets per pound of basis weight.

## Background
CLAIM OF PRIORITY
This application is a continuation application of copending U.S. patent application Ser. No. 13/548,600, filed Jul. 13, 2012, which claims the benefit of U.S. Provisional Patent Application No. 61/457,991, filed Jul. 28, 2011.


TECHNICAL FIELD
Bath tissue must reconcile several competing imperatives. It must be soft. It must be strong. It must absolutely be flushable and protect the user's hands, while also being effective at cleaning. Bath tissue is primarily used for dry cleaning, although there have been several product entries that were advertised as being suitable for wet cleaning, being primarily, pre-moistened.
Requiring that bath tissue also have significant wet strength immensely complicates the problems that a tissue manufacturer faces, as not only are wet strength and flushability in direct conflict, but softness usually suffers as well when strength is increased, while use of wet tissue can result in linting—conflicting with, if not entirely negating, a bath tissue's raison d'être of cleaning.
BACKGROUND
Against this background, it is apparent that, while some products have reconciled these competing “must-haves” to some extent, there has been a longstanding un-met need for a bath tissue truly surmounting these inherent conflicts. There are also many patents that seem to assume that there is little more to making a viable bath tissue that is usable either dry or premoistened than providing a tissue weight product with significant initial wet strength that decays with time. We have discovered that we can provide a bath tissue that achieves a previously unmatched combination of wet and dry properties by incorporating a minor proportion of cellulosic microfibers into a furnish that is used for bath tissue, then forming a tissue web using a belt creping process, in which a nascent web at a consistency of between about 30 and about 60% is creped from an internally heated creping roll using a creping belt. We have found that, with belt-creping and cellulose microfiber (CMF) content, we can produce sheets that are particularly resistant to linting, even when used wet, while also retaining both sufficient wet strength to protect the user's hand and sufficient softness to be used dry by sensitive users. We have also found that we can substitute a controlled coarseness alkaline peroxide mechanical pulp (APMP) into these wet strength bath tissues as a replacement for eucalyptus kraft, and obtain excellent softness, wet strength, lint resistance and wet lint resistance, with very small amounts of CMF.
Others have attempted to address the need for a flushable bath tissue that can be used dry or premoistened, with a variety of wet wipe formulations, wherein fibers in the wet wipe are bonded together with a strength resin that is stabilized by a chemical species in the imbuement of the wet wipe, but is destabilized upon exposure to a large quantity of “normal” water. Thus, the wipe remains strong as long as the imbuement is in contact with the wipe in its package and for a period after removal, because the imbuement stabilizes the resin, but, when the imbuement is removed or, more properly, diluted with water, the strength agent is rendered less effective and the wipe, at least in theory, becomes dispersible. A major tissue producer is reported to have attempted to commercialize such a technology that was, however, not well accepted by the market. In another approach involving wet wipes, some circles maintain that flushability does not really require that the sheet disintegrate after flushing as long as the size of the sheet is kept under some fairly small maximum. Limited consumer research that has been conducted, however, indicates that most users will remove and use several sheets of bath tissue from the roll at a time, so that the sheet used has an area several times that of the so-called “flushable wet wipe” in which “flushability” is predicated upon the size of the sheet.
In contrast, the present invention is based upon a product that can be stored dry on a perforated roll and used like a conventional bath tissue employing a convenient number of unseparated sheets, as the user prefers. If, however, premoistened shortly before use, the tissue retains a sufficient wet strength to be used in the moist state without linting, pilling or shredding, but will disintegrate within a reasonable time after flushing, so that the effectiveness of plumbing is not unduly compromised. Significantly, these goals are achieved without requiring another product in the bathroom; although some users may prefer to use a small container, such as a spray bottle to hold aqueous liquid for moistening the sheet immediately before use. Such bottles can be conveniently disposed inside the roll core of packaged tissue, as promotional or introductory items, if desired.
As use of the present invention makes it possible to achieve quite a high wet/dry ratio, softness does not unduly suffer, as the actual dry tensile strength, which is strongly associated—negatively—with perceived softness, can be moderate, while the wet strength can remain quite high in the first minutes after moistening. Thus, the strength and softness of the tissue of the present invention can be comparable to that of premium bath tissue, while retaining a high temporary wet strength. Even though, when used with conventional papermaking furnishes, many wet strength resins make it possible to achieve wet strength levels necessary for the tissue to be employed premoistened, in many cases, the tactile properties of the dry sheet can be somewhat compromised thereby.
When employing substantial amounts of cellulosic microfibers in the furnish, in conjunction with temporary wet strength resin and belt-creped paper making technology, we have found that we can achieve a surprisingly good combination of softness, opacity, wet strength and resistance to pilling and shredding in a flushable bath tissue. In addition, the flushable bath tissue is capable of being stored on a roll, as is conventional bath tissue, and suitable for use either dry or premoistened. When alkaline peroxide mechanically pulped (APMP) eucalyptus fiber is included, we have found that we can obtain excellent results, even using far less of the cellulosic microfiber, even when using conventional wet press (CWP) technology. We have further discovered that the APMP eucalyptus fiber is an excellent substitute for conventional eucalyptus kraft fiber in conventional bath tissue, imparting increased opacity, bulk, softness, absorbency and reduced strength, even to tissue made with recycle furnishes.
One early pre-wettable tissue was disclosed in Bhat et al., “Prewettable High Softness Paper Product Having Temporary Wet Strength”, U.S. Pat. No. 5,958,187, Sep. 28, 1999, relating to a paper product with a glabrous surface and adapted for use either dry or use in a manually pre-moistened condition. Bhat et al. disclose a paper product having a temporary wet strength and exhibiting an initial normalized cross machine direction (CD) wet tensile strength of at least about 25 g/in. strip, preferably, 35 g/in. strip as measured by the Finch Cup Test 5 seconds after immersion, and a subsequent CD wet tensile strength of less than about 2⁄3 the initial value as measured 30 minutes after immersion. Temporary wet strength was provided by addition to the furnish of a temporary wet strength agent comprising aldehydic units in the range of from about 2 pounds per ton to about 30 pounds per ton. The furnish also included a cationic nitrogenous softener/debonder in an amount of from about 1 pound per ton to about 6 pounds per ton. The CD dry tensile strength of the paper product was from about 133 g/in. strip up to about 267 g/in. strip, and the tensile modulus was from about 10 to about 32 g/% strain, while the geometric mean friction deviation (GM MMD value) was from about 0.26 to about 0.10. The CD wet strength of the product decays to about 15 g/in. within 10 hours after immersion. When rubbed against a skin-like surface in a moistened condition, the paper product remains substantially free of pilling. Significantly, in Bhat et al., the wet abrasion resistance of a 2′′ by 4.5′′ sample of tissue was measured under a load of 135 grams against a wetted pigskin, and visual observation was made to determine whether the sample left pills, shreds or lint behind.
Another early pre-wettable tissue was disclosed in Van Luu et al. [sic, Luu et al.], “Prewettable High Softness Paper Product Having Temporary Wet Strength”, U.S. Pat. No. 6,059,928, May 9, 2000, in which a temporary wet strength agent comprising uncharged chemical moieties, such as aldehydes, and aldehydes containing polymers, polyols and cyclic ureas, or mixtures thereof, in the range of from about 2 pounds per ton to about 30 pounds per ton are added to the web to provide the temporary wet strength. In this application, glyoxal was preferably sprayed on the sheet after it left the Yankee dryer.
“Belt-Creped, Variable Local Basis Weight Absorbent Sheet Prepared With Perforated Polymeric Belt” is disclosed in Super et al. U.S. Patent Application Publication No. 2010/0186913, now U.S. Pat. No. 8,293,072 (incorporated herein by reference), which produces cellulosic tissue sheets exhibiting a surprising combination of bulk, roll firmness, absorbency and softness, from a sheet with a fiber-enriched higher basis weight, hollow domed regions joined by a network of lower local basis weight connecting regions forming a network in which upwardly and inwardly inflected consolidated fibrous regions exhibiting CD fiber orientation bias form transition areas between the connecting regions and the domed regions. The consolidated fibrous regions are, preferably, saddle shaped and exhibit a matted structure on both their outer and inner surfaces. Related technology is found in the following U.S. Patent Applications and U.S. Patents: U.S. Pat. No. 7,494,563 entitled “Fabric Creped Absorbent Sheet with Variable Local Basis Weight”, U.S. Pat. No. 7,399,378 entitled “Fabric Crepe Process for Making Absorbent Sheet”, U.S. Pat. No. 7,789,995 entitled “Fabric Crepe/Draw Process for Producing Absorbent Sheet”, the application of which was a continuation-in-part of the application of U.S. Pat. No. 7,399,378 entitled “Fabric Crepe Process for Making Absorbent Sheet”, U.S. Pat. No. 7,442,278 entitled “Fabric Crepe and In Fabric Drying Process for Producing Absorbent Sheet”, U.S. Pat. No. 7,503,998 entitled “High Solids Fabric Crepe Process for Producing Absorbent Sheet With In-Fabric Drying”, U.S. Pat. No. 7,662,257 entitled “Multi-Ply Paper Towel With Absorbent Core”, U.S. Pat. No. 7,588,660 entitled “Wet-Pressed Tissue and Towel Products With Elevated CD Stretch and Low Tensile Ratios Made With a High Solids Fabric Crepe Process”, and U.S. Pat. No. 7,585,389 entitled “Method of Making Fabric-Creped Sheet for Dispensers”, U.S. Pat. No. 7,850,823 entitled “Method of Controlling Adhesive Build-Up on a Yankee Dryer”, U.S. Pat. No. 7,651,589 entitled “Process for Producing Absorbent Sheet”, U.S. Pat. No. 7,662,255 entitled “Absorbent Sheet”, and U.S. Pat. No. 7,670,457, which are each a division of the application of U.S. Pat. No. 7,442,278; U.S. Pat. No. 7,588,661 entitled “Fabric Crepe Process for Making Absorbent Sheet”, and U.S. Pat. No. 7,704,349 entitled “Fabric Crepe Process for Making Absorbent Sheet”, which are both a division of the application of U.S. Pat. No. 7,399,378, and U.S. Pat. No. 7,670,457 entitled “Process for Producing Absorbent Sheet”. The papermaking technology disclosed in the foregoing documents in this paragraph, the disclosures of which are all incorporated herein by reference in their entireties, makes it possible to form sheets with extremely high bulk stretch and absorbency.
Canadian Patent Application No. 2,095,554 in the name of William D. Lloyd, published Aug. 6, 1994, discloses that hardwood bleached chemical thermomechanical pulp (BCTMP) fibers at amounts of about 5 weight percent or greater provide a soft tissue useful for use as facial or bath tissue, but fails to disclose the degree of bleaching and chemical refining applied to his fibers and is devoid of information concerning the brightness, lignin content or Kappa number of his fibers, other than to state that the fibers contain “substantial amounts of lignin” and the that pulping yield is “about 90% or greater”. Lloyd also states that “it is not necessary to bury the BCTMP fibers in the middle of the tissue sheet by layering. Instead, the tissue sheets can be blended using a mixture of hardwood BCTMP fibers (for softness) and longer softwood fibers (for strength). If a layered tissue is preferred, the hardwood BCTMP fibers can be utilized in the outer layer(s).”
SUMMARY OF THE INVENTION
We have found that we can achieve this desirable combination of properties in a two- or three-ply sheet formed from belt creped cellulosic basesheet, the multi-ply sheet having a basis weight of from about 20 to about 35 lbs and comprising from about 10% to about 30% cellulosic microfiber, from about 70% to about 90% wood pulp fibers, with a geometric mean (GM) dry tensile of from about 35 to 80 g/3 in. per pound of basis weight, a CD dry tensile of between about 30 to about 60 g/3 in. per pound of basis weight, sufficient wet strength resin to provide a CD wet tensile of from about 8.5 to about 20 g/3 in. per pound of basis weight, and a caliper of at least 5 mils per 8 sheets per pound of basis weight. Preferably, such a multi-ply tissue will have an opacity of at least about 2.5 McBeth Opacity Units per pound of basis weight. More preferably, the basis weight will be between 22 and 32 lbs per 3000 sq ft ream. Upon testing for Dry Lint, as referenced herein, sheets of the present invention will exhibit a ΔL* of less than about 6. (“L*” as used in this connection relates to International Commission on Illumination (CIE) 1976, also known as CIELAB measurement of lightness and should not be confused with Hunter lightness, typically denominated “L”. In this connection, the asterisk “*” is not a reference mark directing the reader to some other location in this document, but a portion of the commonly used symbol for CIE 1976 lightness “L*”.) When tested for wet lint as set forth herein, sheets of the present invention will exhibit a Wet Abraded Lint Area of less than about 35 mm2. Alternatively, when tested as set forth herein, resistance to wet linting will be represented by the number of fibers removed having a length of greater than 40 μm, with products of the invention suffering a loss of less than 2500 fibers having a length of greater than 40 μm.
We also have discovered that inclusion of eucalyptus pre-conditioning refiner chemical alkaline peroxide mechanical pulp (APMP) into tissue formulations intended to be used pre-wetted makes it possible to dramatically improve the performance of these tissues, even with concentrations of cellulosic microfiber below the 10% by weight level in conventional wet press technology (i.e., CWP) tissues. U.S. Provisional Patent Application No. 61/574,200, entitled “High Softness, High Durability Bath Tissue Incorporating High Lignin Eucalyptus Fiber”, filed on Jul. 28, 2011, naming Jeffrey A. Lee and Daniel W. Sumnicht as inventors, illustrates the suitability of eucalyptus pre-conditioning refiner chemical alkaline peroxide mechanical pulp referred to herein as eucalyptus (APMP). We have found that we can get surprisingly good softness, bulk and wet properties using eucalyptus APMP, in conjunction with relatively low contents of CMF, even in CWP products. Accordingly, it is evident that eucalyptus APMP can be substituted into the formulations described elsewhere in this application to significant benefit, particularly, in cases when the amount of CMF is below 20% by weight.



BRIEF DESCRIPTION OF THE DRAWINGS
The invention is described with reference to the drawings, wherein:
FIG. 1 is a schematic illustration of a shaker for use in the “Dispersibility Test” described herein.
FIG. 2 is a schematic illustration of a fixture used for holding the test bottle used in the “Dispersibility Test” upright, while the contents are being drained therefrom.
FIG. 3 is photomicrograph of a perforated polymeric belt suitable for the practice of the present invention.
FIGS. 4 and 5 are schematic illustrations of papermachine configurations suitable for the practice of the present invention, FIG. 4 being a so-called crescent former and FIG. 5 being a twin wire.
FIGS. 6A to 6D are photographs of black felts used in the “Dry Lint Test” described herein.
FIG. 7 is a graphical representation of results of softness and tensile testing described in Example 1 hereof, wherein QN UP represents Quilted Northern® Ultra Plush and QN SS represents Quilted Northern® Soft & Strong.
FIGS. 8A to 8D are graphical comparisons of properties of tissues of the present invention, particularly, softness, as compared to commercially available tissue products illustrating that Applicants have succeeded in manufacturing dispersible (flushable) temporary wet strength bath tissues that not only can achieve at least parity softness with conventional ultra premium bath tissue, but have sufficient temporary wet strength to be usable pre-wetted without leaving excessive lint behind in use, whether used pre-wetted or dry.
FIGS. 9A to 9E are photographs of black felts used in the “Wet Abrasion Lint Test” described herein, of tissues described in Example 3 hereof.
FIG. 10 is photomicrograph of a perforated polymeric belt suitable for the practice of the present invention, while FIG. 11 is a schematic scale drawing of the perforated polymeric belt shown in FIG. 10.
FIGS. 12 and 13 compare the Dry and Wet Lint properties of tissues of the present invention to commercially available tissues.
FIG. 14 illustrates a schematic sectional view of a three-ply tissue with two stratified outer plies and a homogeneous inner ply, wherein eucalyptus alkaline peroxide mechanical pulp (APMP) is incorporated in all three plies.
FIG. 15 is a bubble graph illustrating the inter-relationship among the softness, CD wet strength and wet linting resistance of several prototype products.
FIG. 16 is a bubble graph illustrating the inter-relationship among dispersibility, CD wet strength and resistance to wet linting of several prototype products.
FIG. 17 illustrates the dry tensile strength and softness of several prototype tissue products.
FIG. 18 illustrates the caliper and basis weight of CWP prototype tissue products in comparison with those of Fabric Reorienting Belt Creping (“FRBC”) prototypes.
FIG. 19 illustrates the softness and wet lint resistance of CWP prototype tissue products in comparison with those of FRBC prototypes with bubble size representing basis weight.
FIG. 20 is a schematic illustration of a glass microscope slide marked for use in the “Wet Abrasion Lint Test” test described herein.
FIGS. 21 to 23 are sectional scanning electron micrographs (SEM's) illustrating domed structures having consolidated regions formed therein.
FIG. 24 is a schematic of the process of preparing eucalyptus APMP.
FIGS. 25 and 26 illustrate a fixture used for measuring roll compression of towel and tissue products. (FIG. 26 is a sectional view taken along line 28-28 of FIG. 25.)
FIGS. 27, 27A to 27F, 27H, and 27T illustrate details of the emboss pattern U 19 referred to herein.
FIGS. 28, 28-A to 28-H, 28-J, 28-1, and 28-2 illustrate details of the emboss pattern HVS 9 referred to herein.
FIG. 29 illustrates the decay of CD wet tensile of various products evaluated herein.



DETAILED DESCRIPTION
The invention is described below with reference to numerous embodiments. Such a discussion is for purposes of illustration only. Modifications to particular examples within the spirit and scope of the present invention, set forth in the appended claims, will be readily apparent to one of skill in the art.
Terminology used herein is given its ordinary meaning consistent with the exemplary definitions set forth immediately below: mg refers to milligrams and m2 refers to square meters, mm2 refers to square millimeters, and so forth.
The creping adhesive “add-on” rate is calculated by dividing the rate of application of adhesive (mg/min) by surface area of the drying cylinder passing under a spray applicator boom (m2/min). The resinous adhesive composition most preferably consists essentially of a polyvinyl alcohol resin and a polyamide-epichlorohydrin resin, wherein the weight ratio of polyvinyl alcohol resin to polyamide-epichlorohydrin resin is from about 2 to about 4. The creping adhesive may also include modifier sufficient to maintain good transfer between the creping belt and the Yankee cylinder, generally, less than 5% by weight modifier, and, more preferably, less than about 2% by weight modifier, for peeled products. For blade creped products, from about 5% to about 25% modifier or more may be used.
Throughout this specification and claims, when we refer to a nascent web having an apparently random distribution of fiber orientation (or use like terminology), we are referring to the distribution of fiber orientation that results when known forming techniques are used for depositing a furnish on the forming fabric. When examined microscopically, the fibers give the appearance of being randomly oriented, even though, depending on the jet to wire speed ratio, there may be a significant bias toward machine direction orientation making the machine direction tensile strength of the web exceed the cross-direction tensile strength.
In many applications related to U.S. Pat. No. 7,399,378, entitled “Fabric Crepe Process for Making Absorbent Sheet”, the importance of the distinction between creping using a woven fabric and a creping belt formed by perforating a solid belt was of minor importance, so the term “belt” could apply to either creping medium. In this application, however, as well as in U.S. patent application Ser. No. 12/694,650, filed on Jan. 27, 2010, entitled “Belt-Creped, Variable Local Basis Weight Absorbent Sheet Prepared With Perforated Polymeric Belt” and published as U.S. Patent Application Publication No. 2010/0186913, now U.S. Pat. No. 8,293,072, the distinction between the use of a creping fabric and a perforated polymeric belt is of considerable importance, as it has been found that use of a perforated polymeric belt makes it possible to obtain consolidated regions, particularly, consolidated saddle shaped regions, in the web, giving it improved physical properties over the webs previously formed using the technique of creping from a transfer drum. For convenience, we refer to this method of forming a sheet as Fiber Reorienting Belt Creping or FRBC. Further, in this application, it is demonstrated that CMF containing wipers made using a perforated polymeric belt have substantial performance advantages over wipers made using a woven creping fabric, which we term Fiber Reorienting Fabric Creping or FRFC. Throughout this application, we have endeavored to make this distinction explicit, but, definitional language in applications incorporated by reference notwithstanding, in this application, belts and creping fabrics should not be considered to be synonymous.
Unless otherwise specified, “basis weight”, BWT, bwt, BW, and so forth, refers to the weight of a 3000 square-foot ream of product (basis weight is also expressed in g/m2 or gsm). Likewise, “ream” means a 3000 square-foot ream, unless otherwise specified. Local basis weights and differences therebetween are calculated by measuring the local basis weight at two or more representative low basis weight areas within the low basis weight regions and comparing the average basis weight to the average basis weight at two or more representative areas within the relatively high local basis weight regions. For example, if the representative areas within the low basis weight regions have an average basis weight of 15 lbs/3000 ft2 ream and the average measured local basis weight for the representative areas within the relatively high local basis regions is 20 lbs/3000 ft2 ream, the representative areas within high local basis weight regions have a characteristic basis weight of ((20−15)/15)×100% or 33% higher than the representative areas within low basis weight regions. Preferably, the local basis weight is measured using a beta particle attenuation technique as referenced herein. In some cases, X-ray techniques can be suitably provided that the X-rays are sufficiently “soft”—that the energy of the photons is sufficiently low and the basis weight differences between the various regions of the sheet are sufficiently high, so that significant differences in attenuation are attained.
“Belt crepe ratio” is an expression of the speed differential between the creping belt and the forming wire, and is typically calculated as the ratio of the web speed immediately before belt creping and the web speed immediately following belt creping, the forming wire and transfer surface being typically, but not necessarily, operated at the same speed:

Belt crepe ratio=transfer cylinder speed÷creping belt speed.

Belt crepe can also be expressed as a percentage calculated as:

Belt crepe=[Belt crepe ratio−1]×100.

A web creped from a transfer cylinder with a surface speed of 750 fpm to a belt with a velocity of 500 fpm has a belt crepe ratio of 1.5 and a belt crepe of 50%.
For reel crepe, the reel crepe ratio is typically calculated as the Yankee speed divided by reel speed. To express reel crepe as a percentage, one (1) is subtracted from the reel crepe ratio and the result multiplied by 100.
The belt crepe/reel crepe ratio is calculated by dividing the belt crepe by the reel crepe.
The line or overall crepe ratio is calculated as the ratio of the forming wire speed to the reel speed and a % total crepe is:

Line Crepe−[Line Crepe Ratio−1]/100.

A process with a forming wire speed of 2000 fpm and a reel speed of 1000 fpm has a line or total crepe ratio of 2 and a total crepe of 100%.
“Belt side” and like terminology refers to the side of the web that is in contact with the creping belt. “Dryer-side” or “Yankee-side” is the side of the web in contact with the drying cylinder, typically, opposite to the belt-side of the web in many papermaking configurations. In these configurations, the belt side could also be referred to as the air side. The air side, however, is always opposite to the Yankee side. In this application, “belt side” is determined when the sheet is in contact with the transfer cylinder from which it is creped by the creping belt.
Calipers and/or bulk reported herein may be measured at 8 or 16 sheet calipers as specified. The sheets are stacked and the caliper measurement taken about the central portion of the stack. Preferably, the test samples are conditioned in an atmosphere of 23°+1.0° C. (73.4°+1.8° F.) at 50% relative humidity for at least about 2 hours and then measured with a Thwing-Albert Model 89-II-JR or Progage Electronic Thickness Tester with 2-in diameter anvils, 539±10 grams dead weight load, and 0.231 in/sec descent rate. For finished product testing, each sheet of product to be tested must have the same number of plies as the product as sold. For testing in general, eight sheets are selected and stacked together. For napkin testing, napkins are unfolded prior to stacking. For base sheet testing off of winders, each sheet to be tested must have the same number of plies as produced off of the winder. For base sheet testing off of the papermachine reel, single plies must be used. Sheets are stacked together aligned in the machine direction (MD). Bulk may also be expressed in units of volume/weight by dividing caliper by basis weight.
The term “cellulosic”, “cellulosic sheet”, and the like, is meant to include any wet-laid product incorporating papermaking fiber having cellulose as a major constituent. “Papermaking fibers” include virgin pulps or recycle (secondary) cellulosic fibers or fiber mixes comprising cellulosic fibers. Fibers suitable for making the webs of this invention include nonwood fibers, such as cotton fibers or cotton derivatives, abaca, kenaf, sabai grass, flax, esparto grass, straw, jute hemp, bagasse, milkweed floss fibers, and pineapple leaf fibers, and wood fibers, such as those obtained from deciduous and coniferous trees, including softwood fibers, such as northern and southern softwood kraft fibers, hardwood fibers, such as eucalyptus, maple, birch, aspen, or the like. Papermaking fibers can be liberated from their source material by any one of a number of chemical pulping processes familiar to one experienced in the art, including sulfate, sulfite, polysulfide, soda pulping, etc. The pulp can be bleached, if desired, by chemical means, including the use of chlorine, chlorine dioxide, oxygen, alkaline peroxide, and so forth. The products of the present invention may comprise a blend of conventional fibers (whether derived from virgin pulp or recycle sources) and high coarseness lignin-rich tubular fibers, mechanical pulps, such as bleached chemical thermomechanical pulp (BCTMP). “Furnishes” and like terminology refers to aqueous compositions including papermaking fibers, optionally, wet strength resins, debonders, and the like, for making paper products. Recycle fiber is typically more than 50% by weight hardwood fiber and may be 75% to 80% or more hardwood fiber.
As used herein, the term “compactively dewatering the web” (or furnish) refers to mechanical dewatering by overall wet pressing, such as on a dewatering felt, for example, in some embodiments, by use of mechanical pressure applied continuously over the web surface as in a nip between a press roll and a press shoe, wherein the web is in contact with a papermaking felt. The terminology “compactively dewatering” is used to distinguish from processes wherein the initial dewatering of the web is carried out largely by thermal means, as is the case, for example, in U.S. Pat. No. 4,529,480 to Trokhan and U.S. Pat. No. 5,607,551 to Farrington et al. Compactively dewatering a web thus refers, for example, to removing water from a nascent web having a consistency of less than 30% or so by application of pressure thereto and/or increasing the consistency of the web by about 15% or more by application of pressure thereto, that is, increasing the consistency, for example, from 30% to 45%.
Consistency refers to % solids of a nascent web, for example, calculated on a bone dry basis. “Air dry” means including residual moisture, by convention, up to about 10% moisture for pulp and up to about 6% for paper. A nascent web having 50% water and 50% bone dry pulp has a consistency of 50%.
Consolidated fibrous structures are those that have been so highly densified that the fibers therein have been compressed to ribbon-like structures and the void volume is reduced to levels approaching or perhaps even less than those found in flat papers, such as are used for communication purposes. In preferred structures, the fibers are so densely packed and closely matted that the distance between adjacent fibers is typically less than the fiber width, often less than half or even less than a quarter of the fiber width. In the most preferred structures, the fibers are largely collinear and strongly biased in the machine direction (MD). The presence of consolidated fiber or consolidated fibrous structures can be confirmed by examining thin sections that have been imbedded in resin, then, microtomed in accordance with known techniques. Alternatively, if scanning electron microscope images (SEM's) of both faces of a region are so heavily matted as to resemble flat paper, then that region can be considered to be consolidated. Sections prepared by focused ion beam cross section polishers, such as those offered by JEOL® USA, Inc., 11 Dearborn Road, Peabody, Mass., 01960, are especially suitable for observing densification throughout the thickness of the sheet, to determine whether regions in the tissue products of the present invention have been so highly densified as to become consolidated.
Creping belt and like terminology refers to a belt that bears a perforated pattern suitable for practicing the process of the present invention. In addition to perforations, the belt may have features, such as raised portions and/or recesses between perforations, if so desired. Preferably, the perforations are tapered, which appears to facilitate transfer of the web, especially, from the creping belt to a dryer, for example. Typically, the face of the sheet contacting the web during the fabric creping step will have a greater open area than the face away from the web. In some embodiments, the creping belt may include decorative features, such as geometric designs, floral designs, and so forth, formed by rearrangement, deletion, and/or combination of perforations having varying sizes and shapes.
“Domed”, “dome-like”, and so forth, as used in the description and claims, generally refer to hollow, arched protuberances in the sheet of the class seen in the various Figures and is not limited to a specific type of dome structure. The terminology refers to vaulted configurations, generally, whether symmetric or asymmetric about a plane bisecting the domed area. Thus, “domed” generally refers to spherical domes, spheroidal domes, elliptical domes, ellipsoidal domes, oval domes, domes with polygonal bases and related structures, generally including a cap and sidewalls, preferably, inwardly and upwardly inclined, that is, the sidewalls being inclined toward the cap along at least a portion of their length. Cross-sectional photomicrographs are shown of such domed structures in FIGS. 21 to 23.
FPM, Fpm and fpm refer to feet per minute, while fps refers to feet per second.
MD means machine direction and CD means cross-machine direction.
When applicable, MD bending length (cm) of a product is determined in accordance with American Society for Testing and Materials (ASTM) test method D 1388-96, cantilever option. Reported bending lengths refer to MD bending lengths, unless a CD bending length is expressly specified. The MD bending length test was performed with a Cantilever Bending Tester available from Research Dimensions, 1720 Oakridge Road, Neenah, Wis., 54956, which is substantially the apparatus shown in the ASTM test method, item 6. The instrument is placed on a level, stable surface, horizontal position being confirmed by a built in leveling bubble. The bend angle indicator is set at 41.5° below the level of the sample table. This is accomplished by setting the knife edge appropriately. The sample is cut with a one inch strip cutter available from Thwing-Albert Instrument Company, 14 Collins Avenue, W. Berlin, N.J. 08091. Six (6) samples are cut: 1 inch×8 inch machine direction specimens. Samples are conditioned at 23° C.±1° C. (73.4° F.±1.8° F.) at 50% relative humidity for at least two hours. For machine direction specimens, the longer dimension is parallel to the machine direction. The specimens should be flat, free of wrinkles, bends or tears. The Yankee-side of the specimens is also labeled. The specimen is placed on the horizontal platform of the tester, aligning the edge of the specimen with the right hand edge. The movable slide is placed on the specimen, being careful not to change its initial position. The right edge of the sample and the movable slide should be set at the right edge of the horizontal platform. The movable slide is displaced to the right in a smooth, slow manner, at approximately 5 inch/minute until the specimen touches the knife edge. The overhang length is recorded to the nearest 0.1 cm. This is done by reading the left edge of the movable slide. Three specimens are preferably run with the Yankee-side up and three specimens are preferably run with the Yankee-side down, on the horizontal platform. The MD bending length is reported as the average overhang length in centimeters, divided by two to account for bending axis location.
Nip parameters include, without limitation, nip pressure, nip width, backing roll hardness, creping roll hardness, belt approach angle, belt takeaway angle, uniformity, nip penetration and velocity delta between surfaces of the nip.
Nip width (or length as the context indicates) means the MD length over which the nip surfaces are in contact.
PLI or pli means pounds force per linear inch. The process employed is distinguished from other processes, in part, because belt creping is carried out under pressure in a creping nip. Typically, rush transfers are carried out using suction to assist in detaching the web from the donor fabric and, thereafter, attaching it to the receiving or receptor fabric. In contrast, suction is not required in a belt creping step, so, accordingly, when we refer to belt creping as being “under pressure,” we are referring to loading of the receptor belt against the transfer surface, although suction assist can be employed at the expense of further complication of the system, as long as the amount of suction is not sufficient to undesirably interfere with rearrangement or redistribution of the fiber.
Pusey and Jones (P&J) hardness (indentation) is measured in accordance with ASTM D 531, and refers to the indentation number (standard specimen and conditions).
“Predominantly” means more than 50% of the specified component, by weight, unless otherwise indicated.
Roll compression is measured by compressing the roll 285 under a 1500 g flat platen 281 of a test apparatus 283 similar to that shown in FIGS. 25 and 26. Sample rolls 285 are conditioned and tested in an atmosphere of 23.0°+1.0° C. (73.4°+1.8° F.). A suitable test apparatus 283 with a movable 1500 g platen 281 (referred to as a height gauge) is available from:

    
    
        Research Dimensions
        1720 Oakridge Road
        Neenah, Wis. 54956
        920-722-2289
        920-725-6874 (FAX).
    
    


The test procedure is generally as follows:
(a) Raise the platen 281 and position the roll 285 to be tested on its side, centered under the platen, with the tail seal 287 to the front of the gauge 291 and the core 289 parallel to the back of the gauge 291.
(b) Slowly lower the platen 281 until it rests on the roll 285.
(c) Read the compressed roll diameter or sleeve height from the gauge pointer 293 to the nearest 0.01 inch (0.254 mm).
(d) Raise the platen 281 and remove the roll 285.
(e) Repeat for each roll or sleeve to be tested.
To calculate roll compression (RC) in percent, the following formula is used:




  
    RC
    ⁡
    
      (
      %
      )
    
  
  =
  
    100
    ×
    
      
        
          (
          
            
              initial
              ⁢
              
                
              
              ⁢
              roll
              ⁢
              
                
              
              ⁢
              diameter
            
            -
            
              compressed
              ⁢
              
                
              
              ⁢
              roll
              ⁢
              
                
              
              ⁢
              diameter
            
          
          )
        
        
          initial
          ⁢
          
            
          
          ⁢
          roll
          ⁢
          
            
          
          ⁢
          diameter
        
      
      .
    
  




Dry tensile strengths (MD and CD), stretch, ratios thereof, modulus, break modulus, stress and strain are measured with a standard Instron test device or other suitable elongation tensile tester, which may be configured in various ways, typically, using 3 inch or 1 inch wide strips of tissue or towel, conditioned in an atmosphere of 23°±1° C. (73.4°±1° F.) at 50% relative humidity for 2 hours. The tensile test is run at a crosshead speed of 2 in/min. Break modulus is expressed in grams/3 inches/% strain or its SI equivalent of g/mm/% strain. % strain is dimensionless and need not be specified. Unless otherwise indicated, values are break values. GM refers to the square root of the product of the MD and CD values for a particular product. Tensile energy absorption (TEA), which is defined as the area under the load/elongation (stress/strain) curve, is also measured during the procedure for measuring tensile strength. Tensile energy absorption is related to the perceived strength of the product in use. Products having a higher TEA may be perceived by users as being stronger than similar products that have lower TEA values, even if the actual tensile strength of the two products are the same. In fact, having a higher tensile energy absorption may allow a product to be perceived as being stronger than one with a lower TEA, even if the tensile strength of the high-TEA product is less than that of the product having the lower TEA. When the term “normalized” is used in connection with a tensile strength, it simply refers to the appropriate tensile strength from which the affect of basis weight has been removed by dividing that tensile strength by the basis weight. In many cases, similar information is provided by the term “breaking length”.
Tensile ratios are simply ratios of an MD value determined by way of the foregoing methods divided by the corresponding CD value. Unless otherwise specified, a tensile property is a dry sheet property.
“Upper”, “upwardly” and like terminology is used purely for convenience and refers to a position or direction toward the caps of the dome structures, that is, the belt side of the web, which is generally opposite to the Yankee side, unless the context clearly indicates otherwise.
The wet tensile of the tissue of the present invention is measured generally following Technical Association of the Pulp and Paper Industry (TAPPI) Method T 576 pm 7, using a three-inch (76.2 mm) wide strip of tissue that is folded into a loop, clamped in a special fixture termed a Finch Cup, then immersed in water. A suitable Finch cup, 3-in., with base to fit a 3-in. grip, is available from:

    
    
        High-Tech Manufacturing Services, Inc.
        3105-B NE 65th Street
        Vancouver, Wash. 98663
        360-696-1611
        360-696-9887 (FAX).
    
    


For fresh basesheet and finished product (aged 30 days or less for towel product, aged 24 hours or less for tissue product) containing wet strength additive, the test specimens are placed in a forced air oven heated to 105° C. (221° F.) for five minutes. No oven aging is needed for other samples. The Finch cup is mounted onto a tensile tester equipped with a 2.0 pound load cell with the flange of the Finch cup clamped by the tester's lower jaw and the ends of tissue loop clamped into the upper jaw of the tensile tester. The sample is immersed in water that has been adjusted to a pH of 7.0±0.1 and the tensile is tested after a 5 second immersion time using a crosshead speed of 2 inches/minute. The results are expressed in g/3 in., dividing the readout by two to account for the loop as appropriate.
A translating transfer surface refers to the surface from which the web is creped onto the creping belt. The translating transfer surface may be the surface of a rotating drum as described hereafter, or may be the surface of a continuous smooth moving belt or another moving fabric that may have surface texture, and so forth. The translating transfer surface needs to support the web and to facilitate the high solids creping, as will be appreciated from the discussion that follows.
Velocity delta means a difference in linear speed.
The void volume and/or void volume ratio, as referred to hereafter, are determined by saturating a sheet with a nonpolar POROFILTM liquid, available from Coulter Electronics Ltd., Beckman Coulter, Inc., 250 S. Kraemer Boulevard, P.O. Box 8000, Brea, Calif. 92822-8000 USA, and measuring the amount of liquid absorbed. The volume of liquid absorbed is equivalent to the void volume within the sheet structure. The % weight increase (PWI) is expressed as grams of liquid absorbed per gram of fiber in the sheet structure, times one hundred (100), as noted hereafter. More specifically, for each single-ply sheet sample to be tested, select 8 sheets and cut out a 1 inch by 1 inch square in the machine direction and 1 inch in the cross machine direction. For multi-ply product samples, each ply is measured as a separate entity. Multiple samples should be separated into individual single plies and 8 sheets from each ply position used for testing. Weigh and record the dry weight of each test specimen to the nearest 0.0001 gram. Place the specimen in a dish containing POROFILTM liquid having a specific gravity of about 1.93 grams per cubic centimeter, also available from Coulter Electronics Ltd., Beckman Coulter, Inc., Part No. 9902458. After 10 seconds, grasp the specimen at the very edge (1-2 millimeters in) of one corner with tweezers and remove from the liquid. Hold the specimen with that corner uppermost and allow excess liquid to drip for 30 seconds. Lightly dab (less than 1⁄2 second contact) the lower corner of the specimen on #4 filter paper (Whatman Ltd., Maidstone, England) in order to remove any excess of the last partial drop. Immediately weigh the specimen, within 10 seconds, recording the weight to the nearest 0.0001 gram. The PWI for each specimen, expressed as grams of POROFILTM liquid per gram of fiber, is calculated as follows:




  PWI
  =
  
    
      
        (
        
          
            W
            2
          
          -
          
            W
            1
          
        
        )
      
      
        W
        1
      
    
    ×
    100
  




wherein

“W1” is the dry weight of the specimen, in grams; and
“W2” is the wet weight of the specimen, in grams.
The PWI for all eight individual specimens is determined as described above and the average of the eight specimens is the PWI for the sample.
The void volume ratio is calculated by dividing the PWI by 1.9 (density of fluid) to express the ratio as a percentage, whereas the void volume (gms/gm or g/g) is simply the weight increase ratio; that is, PWI divided by 100.
Water absorbency rate, or WAR, is measured in seconds and is the time that it takes for a sample to absorb a 0.1 gram droplet of water disposed on its surface by way of an automated syringe. The test specimens are preferably conditioned at 23° C.±1° C. (73.4±1.8° F.) at 50% relative humidity for 2 hours. For each sample, 4 test specimens 3′′×3′′ are prepared. Each specimen is placed in a sample holder such that a high intensity lamp is directed toward the specimen. 0.1 ml of water is deposited on the specimen surface and a stop watch is started. When the water is absorbed, as indicated by a lack of further reflection of light from the drop, the stopwatch is stopped and the time recorded to the nearest 0.1 seconds. The procedure is repeated for each specimen and the results averaged for the sample. WAR is measured in accordance with TAPPI method T 432 cm-99.
Dry Lint Test
To quantify the amount of lint removed from towel, tissue and related products when used dry, a Sutherland Rub Tester with 4.0-lb rub block is used. This apparatus is available from Danilee Company, 27223 Starry Mountain Street, San Antonio, Tex. 78260, 830-438-7737; 800-438-7738 (FAX). The 4.0-lb rub block for the Rub Tester has dimensions of 2′′ by 4′′ so that the pressure exerted during testing is 0.5 psi.
After the samples to be evaluated are preconditioned at 10 to 35% RH at 22° to 40° C. for 24 hours, then conditioned at 50.0%±2.0% RH and 23.0±1.0° C. for 2 hours, all of the subsequent procedures are performed within the confines of a room maintained at between 48 to 53% RH and a temperature of between 22° C. and 24° C.
Two stacks of four 2.25-in.×4.5-in. test strips with 4.5-in length in the machine direction are cut from the sample with the top (exterior of roll) side up.
Two 2.5-in.×6-in. strips of black felt are cut with the 6-in. length in the machine direction, and the top side labeled with sample ID numbers.
A baseline reading for the felt is determined by taking one L* lightness color reading on the labeled side of each black felt strip used for testing in the middle of what will be the rubbed area using a GretagMacbeth® Ci5 spectrophotometer using the following settings on the spectrophotometer: Large area view; Specular component excluded; UV Source C; 2 degree observer; and Illuminant C. The GretagMacbeth® spectrophotometer Model Ci5 is available from: GretagMacbeth; 617 Little Britain Road, New Windsor, N.Y. 12553; 914-565-7660; 914-565-0390 (FAX); www.gretagmacbeth.com. The “before testing” reading is later compared to the “after testing” reading in the same area of the black felt strip on the same side, so particular care is taken to be sure that comparisons are made only between the same felt strips. “L*” as used in this connection relates to CIE 1976, also known as CIELAB measurement of lightness and should not be confused with Hunter lightness, typically denominated “L”. In this connection, the asterisk “*” is not a reference mark directing the reader to some other location in this document, but a portion of the commonly used symbol for CIE 1976 lightness “L*”.
To evaluate a specimen, the specimen is taped to the galvanized plate on the Sutherland Rub Tester with the top side up, so that rubbing will be in the machine direction with care being observed to ensure that each specimen is taped in the same rub area each time the test is performed. The first black felt specimen is taped, labeled side out, to the bottom of the 4.0-lb rub block of the Sutherland Rub Tester, the number of strokes on the rub tester is set to four, and the slow speed selected (#2 setting for 4 speed model or #1 setting for 2 speed model), the rub block is placed on the Sutherland Rub Tester carriage arm and the “Start” button pressed to start testing. After the four strokes are completed, the rub block is removed from the tester and the black felt is removed from the bottom of the rub block with the black felt being preserved for L* “after testing” color reading. The specimen is removed from the galvanized plate and discarded.
One L* color reading is taken on the labeled side of each black felt strip, reading the same spot used to obtain the “before testing” value, in the middle of the rubbed area. The “after testing” reading is paired up with the appropriate “before testing” reading to calculate a difference between the readings—“ΔL*”.
For each sample, the average, standard deviation, minimum and maximum test results are recorded as measured to the nearest 0.01 L* unit for both the before testing and after testing values. The difference value of the after reading minus the before reading is indicative of the lint removal by the standardized dry rubbing procedure.
Wet Abrasion Lint Test
To evaluate a tissue sample for lint removal by wet abrasion, the sample is first subjected to simulated wet use against a sample of standard black felt with a Crockmeter Rub Tester, modified as described herein. Then, the area in mm2 of the lint left on the felt is measured with an Epson, Perfection 4490 flat bed Scanner and Apogee, SpecScan Software, version 2.3.36.
The Crockmeter Rub available from SDL Atlas, LLC, 3934 Airway Drive, Rock Hill, S.C. 29732; (803) 329-2110. To be used to measure wet lint as described herein, the Crockmeter is modified to accept a 360 gram arm and a 1′′×2′′ foot that exerts a pressure on the specimen of 0.435 psi. The weight of the rub block is 355 g for the weighted arm supported on one end, and 36 g for the rub foot. These weights are exerted on a 1′′×2′′ area, for a pressure of 391 g/12.9 cm2=30.3 g/cm2. In contrast, the method of evaluating wet abrasion in the Bhat et al. and Luu patents referenced herein used a 135 g sled placed on a 2′′×3′′ sample for a pressure of 135 g/38.7 cm2=3.5 g/cm2.
Research Dimensions at 1720 Oakridge Road, Neenah, Wis. 54956, 920-722-2289, will modify Crockmeter Rub Testers to conform hereto.
Suitable black felt is 3/16-inch thick, part #113308F-24 available from Aetna Felt Corporation, 2401 W. Emaus Avenue, Allentown, Pa. 18103; 800-526-4451.
To test a sample, the outer three layers of tissue are removed from the roll. Three sheets of tissue are cut at the perforations and placed in a stack using a paper cutter ensuring that the tissue sheets are placed in the same orientation relative to the direction and the side of the roll. From the stack, samples that are 2-inches by 2.5-inches are cut with the long dimension being the machine direction. Enough samples are cut for 4 replicates. The short (2′′) side of the tissue is marked with a small dot to indicate the surface of the tissue that was outwardly facing when on the roll. The foot is mounted to the arm of the Crockmeter with the short dimension parallel to the stroke of the Crockmeter and the stroke distance set at 4′′±1⁄8 inch, and the stroke speed is set to strokes per minute. The black felt is cut into 3-inch by 6-inch pieces with the inside surface being marked along the short edge. In this test, the tissue sample to be tested will be rubbed against the inside of the felt starting at the mark. A 12-inch by 12-inch sheet of black acrylic, a 2-inch by 3-inch glass slide marked as shown in FIG. 20, tape, a pipette and a beaker of distilled water are located on any nearby convenient flat surface. The Crockmeter is turned on, then turned off, to position the arm at its furthest back position. The spacer is placed under the arm to hold it above the rubbing surface. A clean piece of black felt is taped to the base of the Crockmeter over the rubbing surface with the marked surface oriented upward, with the marked end up adjacent to the beginning point of the stroke of the foot. A sample is taped along one shorter edge to the foot with the top side of the tissue facing up, and the length of the tissue is wrapped around the foot and attached to the arm of the Crockmeter with the taped side and the marked location on the tissue sample facing the operator at the forward portion of the Crockmeter. The type of tape used is not critical. Office tape commonly referred to as cellophane tape or sold under the trademark “Scotch® Tape” is suitable. The spacer is removed from under the arm, and the arm with the attached foot is set down on the black felt with the long dimension of the foot perpendicular to the rub direction, and the foot is fixed in place. The glass microscope slide is placed on the felt forward of the foot and 3 volumes of 200 μL of distilled water each are dispensed from the pipette onto the cross-marks on the glass slide. The sample, foot and arm are gently lifted, the glass slide is placed under the sample and the sample is lowered to allow the water to wet the sample for 5 seconds, after which time the arm is lifted, the glass slide removed and the Crockmeter activated to allow the sample to make three forward strokes on the felt with the arm being lifted manually at the beginning of each return stroke to prevent the sample from contacting the felt during the return strokes. After three forward strokes, the Crockmeter is inactivated and the spacer placed under the arm so that the black felt can be removed without disturbing the abraded lint thereupon. Three minutes after the felt is removed from the rubbing surface, it is scanned in a flat bed scanner using Apogee SpecScan Software with the software being set for “lint” in the “Scanner Settings” window, with “5” being set in the “Process Groups of:” window on the “Defaults panel”, the “Resolution” being set at “600 dots/inch”, the “Scanner Mode” being set to “256-Grayscale”, the “Area Setting” being set to “Special”, the “Scan Image” being set to “Reverse Image”, the “Upper Limit” window on the “Dirt Histogram” panel being set to “>=5.000” the “Lower Limit” window of that panel being set to “0.013-0.020” and the “X Scale:” window being set to “25”; and the “PPM” window of the “Bad Handsheet” panel set to “2500.0”. On the “Printout Settings:” panel, the “Gray-Summary”, “Sheet Summary” and “Gray Histogram” boxes are checked, the “Copies” window is set to “1”, while the “Dirt Histogram”, “Categories” and “XY Location boxes on that panel are unchecked. Both the “Enable Display” and “Enable Zoom” boxes are checked on the Display Mode panel. On the “Scanner Setup” panel, the “White” box is set for “255” while the “Black” box is set for “0”, the “Contrast Filter” box is set for “0.000”, the upper “Threshold=” box is set for 80.0 [% percent of background plus] while the lower “Threshold=” box is set for “0.0” [grayscale value]. The “Percent of Background, plus offset” box on the “Scanner Setup” panel is checked while the “Manual Threshold Setting” and “Function of StdDev of Background” boxes are unchecked. If desired the “Grade Identification:” and “Reel/Load Number:” boxes may be used to record indicia related to the identification of the samples being tested. On the “Special Area Definition” panel, “Inches” is checked in the “Dimensions:” region while “Rectangular” is checked in the “Shape:” region. In the “Border at top and left:” region, “0.15” [in.] is entered in the “At the left side: (X)” box and “0.625” [in.] is entered in the “At the top: (Y)” box. In the “Area to scan:” regions “2.7” [in.] is entered in the “Width (X)” box and “5.2” [in.] is entered in the “Height (Y)” box. After scanning, the area in mm2 of the abraded lint left on the black felt is output in the “SHEETS” Table in the “Total Area” column under the “Sample Sheet(s)” heading on the “Sheet & Category Summary” screen. This result is sometimes referred to herein as “WALA” for Wet Abraded Lint Area, which is reported in mm2.
In other cases, the fiber removed will be washed off and the solution subjected to testing in an Optest Fiber Quality Analyzer to determine the number of fibers that are removed having a length in excess of 40 μm. The Optest Fiber Quality Analyzer has become a standard in the paper industry for determining fiber length distributions and fiber counts above a certain minimal length, (currently, at about 40 μm), which keeps decreasing as Optest continually upgrades their technique.
The Optest Fiber Quality Analyzer is available from:

    
    
        OpTest Equipment Inc.
        900 Tupper SI.—Hawkesbury—ON—K6A 3S3—Canada
        Phone: 613-632-5169; Fax: 613-632-3744.
    
    


Dispersibility Test
To determine how well bathroom tissue disintegrates in water under controlled agitation using a standard water solution, a sample of tissue is placed in a bottle of specified dimensions in a standardized water solution and subjected to controlled agitation using a standardized shaker that shakes the bottle for a preset number of shakes at 180±5 strokes per minute. One stroke is a complete cycle of back and forth. The bottle is then drained in a fixture adapted to hold the bottle with its centerline perpendicular. See FIGS. 1 and 2. More specifically, the test is conducted as follows.
The standardized bottle shaker 50 and bottle guide fixture 52 are available from Research Dimensions, 1720 Oakridge Road, Neenah, Wis. 54956, (920) 722-2289; FAX (920) 725-6874. A small mouth ( 11/16-inch diameter orifice) plastic bottle 54 with cap, 250 ml, is catalog number 02-924-6D, available from Fisher Scientific Company. The Standard Water Solution, catalog number NC9664362, is available from Fisher Scientific Company, 800-766-7000.
Remove and discard the first three layers of tissue from a roll of tissue. (The tissue sample to be tested may be taken from anywhere in the roll except for the three outer wraps and the last 20 sheets from the core.) If the tissue samples and/or base sheet samples are less than 24 hours old, they are to be oven cured for 5 minutes at 105° C.
For testing of a finished product: six 3-sheet strips are cut from the roll. If the product being tested is a multi-ply product, the plies are not separated from each other, but are tested still plied together.
For testing of a base sheet, specimens are to be cut equivalent to the length and width of the finished product for which they are intended. Three specimens are cut for one-ply product, six specimens are cut for two-ply product, and nine specimens are cut for three-ply product.
180±5 ml of standard water at 23° C. (73° F.) is transferred to the bottle 54.
Shaker 50 is set for an appropriate number of strokes. In the case of finished product testing, the three-sheet strip of tissue is folded in half, rolled up and inserted into the plastic bottle 54, which is then capped. In the case of a base sheet, the specimen is folded in half and one strip of tissue is rolled up when the intended finished product is 1-ply, two strips of tissue for 2-ply finished product, and 3 strips of tissue for 3-ply finished product. The roll is inserted into the plastic bottle 54, which is then capped.
Bottle 54 is placed in shaker 50 (FIG. 1) with bottom 51 toward the drive arm 58, and motor 60 started.
After shaker 50 has shaken bottle 54 for the set number of strokes, the contents are immediately checked for disintegration by inverting bottle 54 and placing it into bottle guide fixture 52 (FIG. 2) in one quick motion to see if the contents will pour out into a beaker. In order for the specimen to pass the test for that number of shakes, the entire contents of bottle 54 must empty within eight seconds without shaking or squeezing bottle 54. The test is replicated and a “pass” is recorded only if both specimens pass.
Regenerated Cellulose Microfiber
In accordance with the invention, regenerated cellulose fiber is prepared from a cellulosic dope comprising cellulose dissolved in a solvent comprising tertiary amine N-oxides or ionic liquids. The solvent composition for dissolving cellulose and preparing underivatized cellulose dopes suitably includes tertiary amine oxides such as N-methylmorpholine-N-oxide (NMMO) and similar compounds enumerated in U.S. Pat. No. 4,246,221 to McCorsley, the disclosure of which is incorporated herein by reference. Cellulose dopes may contain non-solvents for cellulose, such as water, alkanols or other solvents, as will be appreciated from the discussion that follows.
Suitable cellulosic dopes are enumerated in Table 1, below.







TABLE 1







EXAMPLES OF TERTIARY AMINE N-OXIDE SOLVENTS









Tertiary Amine N-oxide
% water
% cellulose





N-methylmorpholine
up to 22
up to 38


N-oxide


N,N-dimethyl-ethanol-amine N-oxide
up to 12.5
up to 31


N,N-dimethylcyclohexylamine N-oxide
up to 21
up to 44


N-methylhomopiperidine N-oxide
5.5-20
1-22


N,N,N-triethylamine
  7-29
5-15


N-oxide


2(2-hydroxypropoxy)-
  5-10
2-7.5


N-ethyl-N,N,-dimethyl-amide N-oxide


N-methylpiperidine
up to 17.5
5-17.5


N-oxide


N,N-dimethylbenzylamine
5.5-17
1-20


N-oxide









See, also U.S. Pat. No. 3,508,941 to Johnson, the disclosure of which is incorporated herein by reference.
Details with respect to preparation of cellulosic dopes including cellulose dissolved in suitable ionic liquids and cellulose regeneration therefrom are found in U.S. patent application Ser. No. 10/256,521, U.S. Patent Application Publication No. 2003/0157351 of Swatloski et al., now U.S. Pat. No. 6,824,599, entitled “Dissolution and Processing of Cellulose Using Ionic Liquids”, the disclosure of which is incorporated herein by reference. Here, again, suitable levels of non-solvents for cellulose may be included. There is generally described in this patent application a process for dissolving cellulose in an ionic liquid without derivatization and regenerating the cellulose in a range of structural forms. It is reported that the cellulose solubility and the solution properties can be controlled by the selection of ionic liquid constituents with small cations and halide or pseudohalide anions favoring solution. Preferred ionic liquids for dissolving cellulose include those with cyclic cations, such as the following cations: imidazolium, pyridinum, pyridazinium, pyrimidinium, pyrazinium, pyrazolium, oxazolium, 1,2,3-triazolium, 1,2,4-triazolium, thiazolium, piperidinium, pyrrolidinium, quinolinium, and isoquinolinium.
Processing techniques for ionic liquids/cellulose dopes are also discussed in U.S. Pat. No. 6,808,557 to Holbrey et al., entitled “Cellulose Matrix Encapsulation and Method”, the disclosure of which is incorporated herein by reference. Note also, U.S. Patent Application Publication No. 2005/0288484, now U.S. Pat. No. 7,888,412, of Holbrey et al., entitled “Polymer Dissolution and Blend Formation in Ionic Liquids”, as well as U.S. Patent Application Publication No. 2004/0038031, now U.S. Pat. No. 6,808,557, also of Holbrey et al., entitled “Cellulose Matrix Encapsulation and Method”, the disclosures of which are incorporated herein by reference. With respect to ionic fluids, in general, the following documents provide further detail: U.S. Patent Application Publication No. 2006/0241287, now U.S. Pat. No. 7,763,715, of Hecht et al., entitled “Extracting Biopolymers From a Biomass Using Ionic Liquids”; U.S. Patent Application Publication No. 2006/0240727, of Price et al., entitled “Ionic Liquid Based Products and Method of Using The Same”; U.S. Patent Application Publication No. 2006/0240728, of Price et al., entitled “Ionic Liquid Based Products and Method of Using the Same”; U.S. Patent Application Publication No. 2006/0090271, of Price et al., entitled “Processes For Modifying Textiles Using Ionic Liquids”; and Patent Application Publication No. 2006/0207722, now U.S. Pat. No. 8,318,859, of Amano et al., entitled “Pressure Sensitive Adhesive Compositions, Pressure Sensitive Adhesive Sheets and Surface Protecting Films,” the disclosures of which are incorporated herein by reference. Some ionic liquids and quasi-ionic liquids that may be suitable are disclosed by Imperato et al., Chem. Commun. 2005, 1170-1172, the disclosure of which is incorporated herein by reference.
“Ionic liquid” refers to a molten composition that includes an ionic compound that is preferably a stable liquid at temperatures of less than 100° C. at ambient pressure. Typically, such liquids have a very low vapor pressure at 100° C., less than 75 mBar or so and, preferably, less than 50 mBar or less than 25 mBar at 100° C. Most suitable liquids will have a vapor pressure of less than 10 mBar at 100° C. and often, the vapor pressure is so low that it is negligible and is not easily measurable, since it is less than 1 mBar at 100° C.
Suitable commercially available ionic liquids are BasionicTM ionic liquid products available from BASF (Florham Park, N.J.).
Cellulose dopes including ionic liquids having dissolved therein about 5% by weight underivatized cellulose are commercially available from Sigma-Aldrich Corp., St. Louis, Mo. (Aldrich). These compositions utilize alkyl-methylimidazolium acetate as the solvent. It has been found that chorine-based ionic liquids are not particularly suitable for dissolving cellulose.
After the cellulosic dope is prepared, it is spun into fiber, fibrillated and incorporated into absorbent sheet as described later.
A synthetic cellulose, such as lyocell, is split into micro- and nano-fibers and added to conventional wood pulp. The fiber may be fibrillated in an unloaded disk refiner, for example, or any other suitable technique including using a Pulmac-Fiber (PFI) mill. Preferably, relatively short fiber is used and the consistency kept low during fibrillation. The beneficial features of fibrillated lyocell include, for example, biodegradability, hydrogen bonding, dispersibility, repulpability, and smaller microfibers than obtainable with meltspun fibers.
Fibrillated lyocell or its equivalent has advantages over splittable meltspun fibers. Synthetic microdenier fibers come in a variety of forms. For example, a 3 denier nylon/PET fiber in a so-called pie wedge configuration can be split into 16 or 32 segments, typically, in a hydroentangling process. Each segment of a 16-segment fiber would have a coarseness of about 2 mg/100 m versus eucalyptus pulp at about 7 mg/100 m. Unfortunately, a number of deficiencies have been identified with this approach for conventional wet laid applications. Dispersibility is less than optimal. Melt spun fibers must be split before sheet formation, and an efficient method is lacking. Most available polymers for these fibers are not biodegradable. The coarseness is lower than that of wood pulp, but still high enough that they must be used in substantial amounts and form a costly part of the furnish. Finally, the lack of hydrogen bonding requires other methods of retaining the fibers in the sheet.
Fibrillated lyocell has fibrils that can be as small as 0.1 to 0.25 microns (m) in diameter, translating to a coarseness of 0.0013 to 0.0079 mg/100 m. Assuming these fibrils are available as individual strands—separate from the parent fiber—the furnish fiber population can be dramatically increased at various addition rates. Even fibrils not separated from the parent fiber may provide benefit. It is greatly preferred, however, that the fibrils be independent of the parent fiber from which they are split off. Dispersibility, repulpability, hydrogen bonding, and biodegradability remain product attributes, since the fibrils are cellulose.
Fibrils from lyocell fiber have important distinctions from wood pulp fibrils. The most important distinction is the length of the lyocell fibrils. Wood pulp fibrils are only perhaps microns long, and, therefore, act in the immediate area of a fiber-fiber bond. Wood pulp fibrillation from refining leads to stronger, denser sheets. Lyocell fibrils, however, are potentially as long as the parent fibers. These fibrils can act as independent fibers and improve the bulk while maintaining or improving strength. Southern pine and mixed southern hardwood (MSHW) are two examples of fibers that are disadvantaged relative to premium pulps with respect to softness. The term “premium pulps” used herein refers to northern softwoods and eucalyptus pulps commonly used in the tissue industry for producing the softest bath, facial, and towel grades. Southern pine is coarser than northern softwood kraft, and mixed southern hardwood is both coarser and higher in fines than market eucalyptus. The lower coarseness and lower fines content of premium market pulp leads to a higher fiber population, expressed as fibers per gram (N or Ni>0.2) in Table 3. The coarseness and length values in Table 2 were obtained with an OpTest Fiber Quality Analyzer. Definitions are as follows:



  
    
      L
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            fibers
          
        
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          ⁢
          
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            ⁢
            
              
            
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            fibers
          
        
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            0.2
          
        
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          n
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    =
    
      
        10
        5
      
      ×
      
        sampleweight
        
          
            ∑
            
              all
              ⁢
              
                
              
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              fibers
            
          
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              n
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          100
          CL
        
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      millionfibers
      ⁢
      
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Northern bleached softwood kraft (NBSK) and eucalyptus have more fibers per gram than do southern pine and hardwood. Lower coarseness leads to higher fiber populations and smoother sheets.







TABLE 2







Fiber Properties
















C,
Fines,
Ln,
N,

Ni>0.2 mm


Sample
Type
mg/100 m
%
mm.
MM/g
Ln, i>0.2 mm
MM/g

















Southern HW
Pulp
10.1
21
0.28
35
0.91
11


Southern HW - low
Pulp
10.1
7
0.54
18
0.94
11


Aracruz Eucalyptus
Pulp
6.9
5
0.50
29
0.72
20


Southern SW
Pulp
18.7
9
0.60
9
1.57
3


Northern SW
Pulp
14.2
3
1.24
6
1.74
4


Southern (30 SW/70
Base
11.0
18
0.31
29
0.93
10


30 Southern SW/70
Base
8.3
7
0.47
26
0.77
16









For comparison, the “parent” or “stock” fibers of unfibrillated lyocell have a coarseness of 16.6 mg/100 m before fibrillation and a diameter of about 11 to about 12 μm.
The fibrils of fibrillated lyocell have a coarseness on the order of 0.001 to 0.008 mg/100 m. Thus, the fiber population can be dramatically increased at relatively low addition rates. Fiber length of the parent fiber is selectable, and fiber length of the fibrils can depend on the starting length and the degree of cutting during the fibrillation process.
The dimensions of the fibers passing the 200 mesh screen are on the order of 0.2 micron by 100 micron long. Using these dimensions, one calculates a fiber population of 200 billion fibers per gram. For perspective, southern pine might be three million fibers per gram and eucalyptus might be twenty million fibers per gram. (See Table 2.) It appears that these fibers are the fibrils that are broken away from the original unrefined fibers. Different fiber shapes with lyocell intended to readily fibrillate could result in 0.2 micron diameter fibers that are perhaps 1000 microns or more long instead of 100. As noted above, fibrillated fibers of regenerated cellulose may be made by producing “stock” fibers having a diameter of 10-12 microns or so followed by fibrillating the parent fibers. Alternatively, fibrillated lyocell microfibers have recently become available from Engineered Fibers Technology (Shelton, Conn.) having suitable properties. Particularly preferred materials are more than 40% fiber that is finer than 14 mesh and exhibit a very low coarseness (low freeness). For ready reference, mesh sizes appear in Table 3, below. The current limitations on minimum length detectable by the OpTest make it difficult to precisely ascertain the fiber length distribution of the very short fibrils. It does appear, however, that these are quite important in providing the improved sheet properties of the tissues of the present invention.







TABLE 3







Mesh Size









Sieve Mesh #
Inches
Microns












14
.0555
1400


28
.028
700


60
.0098
250


100
.0059
150


200
.0029
74









Details as to fractionation using the Bauer-McNett Classifier appear in Gooding et al., “Fractionation in a Bauer-McNett Classifier”, Journal of Pulp and Paper Science; Vol. 27, No. 12, December 2001, the disclosure of which is incorporated herein by reference.
In connection with the present invention, an absorbent paper web is made by dispersing papermaking fibers into an aqueous furnish (slurry) and depositing the aqueous furnish onto the forming wire of a papermaking machine. Any suitable forming scheme might be used. For example, an extensive, but non-exhaustive, list in addition to Fourdrinier formers, includes a crescent former, a C-wrap twin wire former, an S-wrap twin wire former, or a suction breast roll former. The forming fabric can be any suitable foraminous member including single layer fabrics, double layer fabrics, triple layer fabrics, photopolymer fabrics, and the like. Non-exhaustive background art in the forming fabric area includes U.S. Pat. Nos. 4,157,276; 4,605,585; 4,161,195; 3,545,705; 3,549,742; 3,858,623; 4,041,989; 4,071,050; 4,112,982; 4,149,571; 4,182,381; 4,184,519; 4,314,589; 4,359,069; 4,376,455; 4,379,735; 4,453,573; 4,564,052; 4,592,395; 4,611,639; 4,640,741; 4,709,732; 4,759,391; 4,759,976; 4,942,077; 4,967,085; 4,998,568; 5,016,678; 5,054,525; 5,066,532; 5,098,519; 5,103,874; 5,114,777; 5,167,261; 5,199,261; 5,199,467; 5,211,815; 5,219,004; 5,245,025; 5,277,761; 5,328,565; and 5,379,808, all of which are incorporated herein by reference in their entireties. One forming fabric particularly useful with the present invention is Voith Fabrics Forming Fabric 2164 made by Voith Fabrics Corporation, Shreveport, La.
Foam-forming of the aqueous furnish on a forming wire or fabric may be employed as a means to form sheets comprising fibers that are somewhat difficult to disperse in conventional aqueous furnishes. Foam forming may be especially advantageous if formation issues are encountered. Foam-forming techniques are disclosed in U.S. Pat. Nos. 6,500,302; 6,413,368; 4,543,156 and Canadian Patent No. 2,053,505, the disclosures of which are incorporated herein by reference. The foamed fiber furnish is made up from an aqueous slurry of fibers mixed with a foamed liquid carrier just prior to its introduction to the headbox. The pulp slurry supplied to the system has a consistency in the range of from about 0.5 to about 7 weight % fibers, preferably, in the range of from about 2.5 to about 4.5 weight %. The pulp slurry is added to a foamed liquid comprising water, air and surfactant containing 50 to 80% air by volume, forming a foamed fiber furnish having a consistency in the range of from about 0.1 to about 3 weight % fiber by simple mixing from natural turbulence and mixing inherent in the process elements. The addition of the pulp as a low consistency slurry results in excess foamed liquid recovered from the forming wires. The excess foamed liquid is discharged from the system and may be used elsewhere or treated for recovery of surfactant therefrom.
The furnish will almost always contain chemical additives to alter the physical properties of the paper produced. These chemistries are well understood by the skilled artisan and may be used in any known combination. Such additives may be surface modifiers, softeners, debonders, strength aids, latexes, opacifiers, optical brighteners, dyes, pigments, sizing agents, barrier chemicals, retention aids, insolubilizers, organic or inorganic crosslinkers, or combinations thereof, the chemicals optionally comprising polyols, starches, PPG esters, PEG esters, phospholipids, surfactants, polyamines, HMCP (Hydrophobically Modified Cationic Polymers), HMAP (Hydrophobically Modified Anionic Polymers), or the like.
The pulp can be mixed with strength adjusting agents such as wet strength agents, dry strength agents, debonders/softeners, and so forth. Suitable wet strength agents are known to the skilled artisan. A comprehensive, but non-exhaustive, list of useful strength aids includes urea-formaldehyde resins, melamine formaldehyde resins, glyoxylated polyacrylamide resins, polyamide-epichlorohydrin resins, and the like. Thermosetting polyacrylamides are produced by reacting acrylamide with diallyl dimethyl ammonium chloride (DADMAC) to produce a cationic polyacrylamide copolymer that is ultimately reacted with glyoxal to produce a cationic cross-linking wet strength resin, glyoxylated polyacrylamide. These materials are generally described in U.S. Pat. No. 3,556,932 to Coscia et al. and U.S. Pat. No. 3,556,933 to Williams et al., both of which are incorporated herein by reference in their entireties. Resins of this type are commercially available under the trade name of PAREZ 631NC by Bayer Corporation (Pittsburgh, Pa.). Different mole ratios of acrylamide/-DADMAC/glyoxal can be used to produce cross-linking resins, which are useful as wet strength agents. Furthermore, other dialdehydes can be substituted for glyoxal to produce thermosetting wet strength characteristics. Of particular utility are the polyamide-epichlorohydrin wet strength resins, an example of which is sold under the trade names Kymene 557LX and Kymene 557H by Hercules Incorporated of Wilmington, Del., and Amres® from Georgia-Pacific Resins, Inc. These resins and the process for making the resins are described in U.S. Pat. No. 3,700,623 and U.S. Pat. No. 3,772,076, each of which is incorporated herein by reference in its entirety. An extensive description of polymeric epihalohydrin resins is given in “Chapter 2: Alkaline-Curing Polymeric Amine-Epichlorohydrin” by Espy in Wet Strength Resins and Their Application (L. Chan, Editor, 1994), herein incorporated by reference in its entirety. A reasonably comprehensive list of wet strength resins is described by Westfelt in Cellulose Chemistry and Technology, volume 13, page 813, 1979, which is also incorporated herein by reference.
Suitable temporary wet strength agents for use in the practice of the present invention include aliphatic and aromatic aldehydes, including glyoxal, malonic dialdehyde, succinic dialdehyde, glutaraldehyde and dialdehyde starches, as well as substituted or reacted starches, disaccharides, polysaccharides, chitosan, or other reacted polymeric reaction products of monomers or polymers having aldehyde groups, and optionally, nitrogen groups. Representative nitrogen containing polymers, which can suitably be reacted with the aldehyde containing monomers or polymers, includes vinyl-amides, acrylamides and related nitrogen containing polymers. These polymers impart a positive charge to the aldehyde containing reaction product. In addition, other commercially available temporary wet strength agents, such as, PAREZ FJ98, a low molecular weight slightly cationic glyoxalated polyacrylamide manufactured by Kemira (Atlanta, Ga.), can be used, along with those disclosed, for example, in U.S. Pat. No. 4,605,702.
The temporary wet strength resin may be any one of a variety of water-soluble organic polymers comprising aldehydic units and cationic units used to increase dry and wet tensile strength of a paper product. Such resins are described in U.S. Pat. Nos. 4,675,394; 5,240,562; 5,138,002; 5,085,736; 4,981,557; 5,008,344; 4,603,176; 4,983,748; 4,866,151; 4,804,769 and 5,217,576, the disclosures of which are incorporated herein in their entireties. Modified starches sold under the trademarks CO-BOND® 1000 and CO-BOND® 1000 Plus, by National Starch and Chemical Company of Bridgewater, N.J., may be used. Prior to use, the cationic aldehydic water soluble polymer can be prepared by preheating an aqueous slurry of approximately 5% solids, maintained at a temperature of approximately 240° F. and a pH of about 2.7 for approximately 3.5 minutes. Finally, the slurry can be quenched and diluted by adding water to produce a mixture of approximately 1.0% solids at less than about 130° F.
Other temporary wet strength agents, also available from National Starch and Chemical Company are sold under the trademarks CO-BOND® 1600 and CO-BOND® 2300. These starches are supplied as aqueous colloidal dispersions and do not require preheating prior to use.
To the extent that dry strength agents are added, suitable dry strength agents include starch, guar gum, polyacrylamides, carboxymethyl cellulose, and the like. Of particular utility is carboxymethyl cellulose, an example of which is sold under the trade name Hercules® CMC, by Hercules Incorporated of Wilmington, Del.
Suitable debonders are likewise known to the skilled artisan. Debonders or softeners may also be incorporated into the pulp or sprayed upon the web after its formation. The present invention may also be used with softener materials including, but not limited to, the class of amido amine salts derived from partially neutralized amines. Such materials are disclosed in U.S. Pat. No. 4,720,383. Evans, Chemistry and Industry, 5 Jul. 1969, pages 893-903; Egan, J. Am. Oil Chemist's Soc., Vol. 55 (1978), pages 118-121; and Trivedi et al., J. Am. Oil Chemist's Soc., June 1981, pages 754-756, incorporated by reference in their entireties, indicate that softeners are often available commercially only as complex mixtures rather than as single compounds. While the following discussion will focus on the predominant species, it should be understood that commercially available mixtures would generally be used in practice.
Hercules® TQ 218 or equivalent is a suitable softener material, which may be derived by alkylating a condensation product of oleic acid and diethylenetriamine. Synthesis conditions using a deficiency of alkylation agent (e.g., diethyl sulfate) and only one alkylating step, followed by pH adjustment to protonate the non-ethylated species, result in a mixture consisting of cationic ethylated and cationic non-ethylated species. A minor proportion (e.g., about 10%) of the resulting amido amine cyclize to imidazoline compounds. Since only the imidazoline portions of these materials are quaternary ammonium compounds, the compositions as a whole are pH-sensitive. Therefore, in the practice of the present invention with this class of chemicals, the pH in the head box should be approximately 6 to 8, more preferably, from about 6 to about 7 and, most preferably, from about 6.5 to about 7.
Quaternary ammonium compounds, such as dialkyl dimethyl quaternary ammonium salts, are also suitable, particularly, when the alkyl groups contain from about 10 to 24 carbon atoms. These compounds have the advantage of being relatively insensitive to pH.
Biodegradable softeners can be utilized. Representative biodegradable cationic softeners/debonders are disclosed in U.S. Pat. Nos. 5,312,522; 5,415,737; 5,262,007; 5,264,082; and 5,223,096, all of which are incorporated herein by reference in their entireties. Biodegradable ester quats are suitable. These softeners are biodegradable by virtue of hydrolyzable ester linkages and are usually made by esterifying ethanol amines (i.e., di- and tri-ethanolamines) with a fatty acid followed by quaternization with dimethyl sulfate, or, more popularly, because of safety, diethylsulfate. A methylated example of such an ester quat has the following structural formula:




wherein R can conveniently be either an oleyl group, CH2(CH2)6CH═CH(CH2)7CH3, or an erucyl group, CH2(CH2)10CH═CH(CH2)7CH3, as these can be derived from oleic and erucic acids. In some embodiments, a particularly preferred debonder composition includes a quaternary amine component as well as a nonionic surfactant.

The nascent web may be compactively dewatered on a papermaking felt. Any suitable felt may be used. For example, felts can have double-layer base weaves, triple-layer base weaves, or laminated base weaves. Preferred felts are those having a laminated base weave design. A wet-press-felt that may be particularly useful with the present invention is Vector 3 made by Voith Fabric (Appleton, Wis.). Background art in the press felt area includes U.S. Pat. Nos. 5,657,797; 5,368,696; 4,973,512; 5,023,132; 5,225,269; 5,182,164; 5,372,876; and 5,618,612. A differential pressing felt as is disclosed in U.S. Pat. No. 4,533,437 to Curran et al. may likewise be utilized.
PREFERRED EMBODIMENTS
The products of this invention are advantageously produced in accordance with the teachings of U.S. Patent Application Publication No. 2010/0186913, now U.S. Pat. No. 8,293,072, “Belt-Creped, Variable Local Basis Weight Absorbent Sheet Prepared With Perforated Polymeric Belt”, wherein, after dewatering, a wet-laid, compactively dewatered web is belt creped at a consistency of from 30-60% as described therein. For purposes of this invention, the creping belt employed is a perforated polymer belt of the class shown in FIGS. 3, 10 and 11. Other suitable belts are described in U.S. Patent Application Publication No. 2010/0186913, now U.S. Pat. No. 8,293,072. Belts having a staggered interpenetrating array of perforations as shown in FIGS. 29G and 41 of U.S. Patent Application Publication No. 2010/0186913 are particularly preferred.
FIG. 3 is a plan view photograph of a portion of a first polymer belt 150 having an upper surface 152 that is generally planar and a plurality of tapered perforations 154, 156 and 158. The belt has a thickness of about 0.2 mm to 1.5 mm. Perforations 154, 156 and 158 may be surrounded by lips as shown in U.S. Patent Application Publication No. 2010/0186913, now U.S. Pat. No. 8,293,072, FIGS. 4 through 9, but this is not required. The perforations on the upper surface are separated by a plurality of flat portions or lands 166, 168 and 170 therebetween that separate the perforations. In the embodiment shown in FIG. 3, each of the upper portions of the perforations 154, 156 and 158 (sheet contacting side) has an open area of about 1500 square mils or so, and are oval in shape with a length of about 50 mils mm along a longer axis 172 and a width of about 36 mils or so along a shorter axis 174 of the perforations 154, 156 and 158, while those on the lower surface (roll contacting side) have an open area of approximately 300 square mils with a length of about 22 mils and a width of about 15 mils. It is greatly preferred that the perforations form a staggered interpenetrating array to provide flexibility to belt 150, to accommodate the varying lengths of the fabric that run across the width of the paper machine. The belt shown in FIG. 3 has about 321 perforations per square inch and an open area of approximately 50% on the sheet contact side and about 10% on the roll contact side of the belt. It is not necessary that the perforations be oval shaped.
FIG. 4 shows a papermachine 220 for use in connection with the present invention. Papermachine 220 is a three fabric loop machine having a forming section 222 generally referred to in the art as a crescent former. Forming section 222 includes headbox 250 depositing a furnish on forming wire 232 supported by a plurality of rolls, such as rolls 242, 245. The forming section also includes a forming roll 248 that supports papermaking felt 252, such that web 254 is formed directly on felt 252. Press section 226 includes felt 252, suction roll 256, press shoe 260 and backing roll 262. Felt run 224 extends to shoe press section 226, wherein the moist web is deposited on backing roll 262 and wet-pressed concurrently with the transfer. Thereafter, web 254 is creped onto belt 350 (top side large openings) in belt crepe nip 274 at roll 272 before being optionally vacuum drawn by suction box 276 and then deposited on Yankee dryer 230 in another press nip 292 using a creping adhesive as noted above. Transfer to a Yankee from the creping belt differs from conventional transfers in a CWP from a felt to a Yankee. In a CWP process, pressures in the transfer nip may be 500 PLI or so, and the pressured contact area between the Yankee surface and the web is close to or at 100%. The press roll may be a suction roll, which may have a P&J hardness of 25 to 30. On the other hand, a belt crepe process of the present invention typically involves transfer to a Yankee with a 4 to 40% pressured contact area between the web and the Yankee surface at a pressure of 250 to 350 PLI. No suction is applied in the transfer nip and a softer pressure roll is used, P&J hardness of 35 to 45. The system includes a suction roll 256, in some embodiments. The three loop system, however, may be configured in a variety of ways in which a turning roll is not necessary. This feature is particularly important in connection with the rebuild of a papermachine, inasmuch as the expense of relocating associated equipment, i.e., the headbox, pulping or fiber processing equipment, and/or the large and expensive drying equipment, such as the Yankee dryer or plurality of can dryers would make a rebuild prohibitively expensive, unless the improvements could be configured to be compatible with the existing facility.
FIG. 5 is a schematic diagram of a papermachine 410 having a conventional twin wire forming section 412, a felt run 414, a shoe press section 416, a creping belt 450 and a Yankee dryer 420 suitable for practicing the present invention. Forming section 412 includes a pair of forming fabrics 422, 424 supported by a plurality of rolls 426, 428, 430, 432, 434, 436 and a forming roll 438. A headbox 440 provides papermaking furnish issuing therefrom as a jet in the machine direction to a nip 442 between forming roll 438 and roll 426 and the fabrics. The furnish forms a nascent web 444 that is dewatered on the fabrics with the assistance of suction, for example, by way of suction box 446.
The nascent web is advanced to a papermaking felt 452, which is supported by a plurality of rolls 451, 453, 454, 455, and the felt is in contact with a shoe press roll 456. The web is of a low consistency as it is transferred to the felt. Transfer may be assisted by suction, for example, roll 451 may be a suction roll, if so desired, or a pickup or suction shoe, as is known in the art. As the web reaches the shoe press roll, it may have a consistency of 10 to 25%, preferably, 20 to 25% or so as it enters nip 458 between shoe press roll 456 and backing roll 462. Backing roll 462 may be a heated roll if so desired. It has been found that increasing steam pressure to backing roll 462 helps to lengthen the time between required stripping of excess adhesive from the cylinder of Yankee dryer 420. Suitable steam pressure may be about 95 psig or so, bearing in mind that backing roll 462 is a crowned roll and creping roll 472 has a negative crown to match, such that the contact area between the rolls is influenced by the pressure in backing roll 462. Thus, care must be exercised to maintain matching contact between rolls 462, 472 when elevated pressure is employed.
Instead of a shoe press roll, roll 456 could be a conventional suction pressure roll. If a shoe press roll is employed, it is desirable and preferred that roll 454 be a suction roll effective to remove water from the felt prior to the felt entering the shoe press nip, since water from the furnish will be pressed into the felt in the shoe press nip. In any case, using a suction roll at 454 is typically desirable to ensure that the web remains in contact with the felt during the direction change as one of skill in the art will appreciate from the diagram.
Web 444 is wet-pressed on the felt in nip 458 with the assistance of press shoe 460. The web is thus compactively dewatered at nip 458, typically, by increasing the consistency by fifteen or more points at this stage of the process. The configuration shown at nip 458 is generally termed a shoe press, in connection with the present invention, backing roll 462 is operative as a transfer cylinder that operates to convey web 444 at a high speed, typically, 1000 fpm to 6000 fpm, to the creping belt. Nip 458 may be configured as a wide or an extended nip shoe press, as is detailed, for example, in U.S. Pat. No. 6,036,820 to Schiel, et al., the disclosure of which is incorporated herein by reference.
The use of particular adhesives cooperates with a moderately moist web (25 to 70% consistency) to adhere it to the Yankee sufficiently, to allow for high velocity operation of the system and high jet velocity impingement air drying, and subsequent peeling of the web from the Yankee. In this connection, a poly(vinyl alcohol)/polyamide adhesive composition, as noted above, is applied at any convenient location between cleaning doctor D and nip 482, such as at location 486, as needed, preferably, at a rate of less than about 40 mg/m2 of sheet.
The web is dried on Yankee cylinder 480, which is a heated cylinder, and by high jet velocity impingement air in Yankee hood 488. Hood 488 is capable of variable temperatures. During operation, the web temperature may be monitored at wet-end A of the hood 488 and dry end B of the hood 488 using an infra-red detector, or any other suitable means if so desired. As the cylinder rotates, web 444 is peeled from the cylinder at 489 and wound on a take-up reel 490. Reel 490 may be operated at 5 to 30 fpm (preferably, 10 to 20 fpm) faster than the Yankee cylinder at steady-state when the line speed is 2100 fpm, for example. Instead of peeling the sheet, a creping doctor C may be used to conventionally dry-crepe the sheet. In any event, a cleaning doctor D mounted for intermittent engagement is used to control build up. When adhesive build-up is being stripped from Yankee cylinder 480, the web is typically segregated from the product on reel 490, preferably, being fed to a broke chute at 495 for recycle to the production process.
Backing roll 462 has a smooth transfer surface 464 that may be provided with adhesive (the same as the creping adhesive used on the Yankee cylinder) and/or release agents, if needed. Web 444 is adhered to transfer surface 464 of backing roll 462 that is rotating at a high angular velocity as the web continues to advance in the machine-direction indicated by arrows 466. On the cylinder, web 444 has a generally random apparent distribution of fiber orientation.
Direction 466 is referred to as the machine direction (MD) of the web as well as that of papermachine 410. Whereas, the cross machine direction (CD) is the direction in the plane of the web perpendicular to the MD.
Web 444 enters nip 458, typically, at consistencies of 10-25% or so, and is dewatered and dried to consistencies of from about 25 to about 70 by the time it is transferred to the top side of the creping belt 450, as shown in the diagram.
Creping belt 450 is supported on a plurality of rolls 468, 472, 473 and a press nip roll 478 and forms a belt crepe nip 474 with backing roll 462, as shown.
The creping belt defines a creping nip over the distance in which creping belt 450 is adapted to contact backing roll 462. That is, a significant pressure is applied to the web against the transfer cylinder. To this end, creping roll 472 may be provided with a soft deformable surface that will increase the width of the creping nip and increase the belt creping angle between the belt and the sheet at the point of contact, or a shoe press roll could be used as creping roll 472 to increase effective contact with the web in high impact belt creping nip 474 when web 444 is transferred to creping belt 450 and advanced in the machine-direction.
The nip pressure in crepe nip 474, that is, the loading between creping roll 472 and backing roll 462 is suitably 20 to 200, preferably, 40 to 70 pounds per linear inch (PLI). A substantial pressure in the nip of about 10 PLI or 20 PLI or more is preferable. One of skill in the art, however, will appreciate that, in a commercial machine, the maximum pressure may be as high as possible, limited only by the particular machinery employed. Thus, pressures in excess of 100 PLI, 500 PLI, 1000 PLI or more may be used, if practical and provided a sufficient velocity delta can be maintained between the transfer roll and creping belt.
After belt creping, the web 444 continues to advance along MD 466 where it is wet-pressed onto Yankee cylinder 480 in transfer nip 482. Optionally, suction is applied to the web by way of a suction box 476, to draw out minute folds, as well as to expand the dome structure discussed hereafter.
Transfer at nip 482 occurs at a web consistency of generally from about 25 to about 70%. At these consistencies, it is difficult to adhere the web to surface 484 of Yankee cylinder 480 firmly enough to remove the web from the belt thoroughly. This aspect of the process is important, particularly when it is desired to use a high velocity drying hood.
The products of the invention are produced with or without application of a vacuum to draw out minute folds to restructure the web and with or without calendering. In many cases, however, it is desirable to use both to promote a more absorbent and uniform product.
Bath tissue of the present invention preferably comprises cellulosic fibers chosen from the group consisting of chemically pulped fibers and mechanically pulped fibers, and from about 5 to about 50% by weight of eucalyptus fibers having a lignin content of at least about 15% by weight, more preferably, from about 10 to about 50% by weight of eucalyptus fibers having a lignin content of at least about 20% by weight, and from about 3 to about 10% by weight of regenerated cellulosic microfiber having a fiber count of greater than 100 million fibers per gram. Typically, paper making fibers useful in the present invention include cellulosic fibers commonly known as wood pulp fibers. Applicable wood pulps include chemical pulps, such as kraft, sulfite and sulfate pulps, as well as mechanical pulps including groundwood, thermomechanical pulp, chemically modified, and the like. Chemical pulps may be used in tissue embodiments since they are known to those of skill in the art to impart a superior tactile sense of softness to tissue sheets made therefrom. Pulps derived from deciduous trees (hardwood) and/or coniferous trees (softwood) can be utilized herein. Such hardwood and softwood fibers can be blended or deposited in layers to provide a stratified web. Additionally, fibers derived from wood pulp, such as cotton linters, bagasse, and the like, can be used. Additionally, fibers derived from recycled paper, which may contain any or all of the categories, as well as other non-fibrous materials, such as fillers and adhesives used to manufacture the original paper product, may be used in the present web.
In one embodiment, particularly, if a two-ply structure is being formed, the plies of the multi-ply fibrous structure may be of the same basesheet formulation or the plies may comprise differing basesheets combined to create desired consumer benefits. In one embodiment, the fibrous structures comprise two plies of substantially identical tissue basesheet. In a preferred embodiment, the fibrous structure comprises a first ply, a second ply, and at least one inner ply, as shown in FIG. 14. A particularly preferred construction is that shown in U.S. Patent Application Publication No. 2009/0297781, now U.S. Pat. No. 8,287,986, in the name of Richard D. Huss et al., entitled “Ultra Premium Bath Tissue”, published Dec. 3, 2009. In many embodiments of the present invention, the web has a plurality of embossments formed therein. In one embodiment, the embossment pattern is applied only to two plies that are bonded either by knurling or glue lamination to a third ply that is either unembossed or far more lightly embossed than the other two. In such structures, the points of the embossed structure of the two embossed sheets are usually in contact with the unembossed or lightly embossed backing sheet, as shown in Dwiggins, U.S. Pat. No. 6,896,768, discussed below. Often, such structures are referred to as having “points to the inside”. In another embodiment, the fibrous structure product is a two-ply product wherein both plies comprise a plurality of embossments, either in a nested structure or a point to point structure. Nested products are disclosed in U.S. Pat. No. 6,413,614 to Giesler et al., “High Softness Embossed Tissue” issued Jul. 2, 2002. Variations or combinations of the rigid-to-resilient and/or rigid-to-rigid embossing processes are well understood by the skilled artisan and could be appropriately used in conjunction with the present invention. For example, nested embossing, point-to-point embossing, and multi-nip embossing processes are also within those configurations appropriate for use with the present invention. See, for example, U.S. Pat. Nos. 5,093,068, 5,091,032, 5,269,983 and 5,030,081 to Galyn A. Schulz.
In one embodiment, the fibrous structure product comprises two or more plies of fibrous structure, wherein at least one of the plies has a plurality of embossments thereon comprising an embossment height from about 600 μm to about 1,200 μm. In another embodiment, the embodiment height is from about 700 μm to about 1,100 μm, and the backing roll is either lightly embossed on unembossed, as disclosed in U.S. Pat. No. 6,896,768 to Dwiggins et al., entitled “Soft Bulky Multi-Ply Product and Method of Making Same”, issued May 24, 2005. The multi-ply fibrous structure product may be in roll form. When in roll form, the multi-ply fibrous structure product may be wound about a core or may be wound without a core.
Example 1
Base sheets having the composition set out in Table 4 were manufactured on a low speed pilot machine using conventional wet press (i.e., CWP) technology, then converted into multi-ply products having the constructions set forth in Table 5.







TABLE 4





basesheet





























Varisott
Caliper
Basis









GP-C
8 Sheet
Weight
Tensile
Stretch






FJ98,
debonder,
mils/8
lb/3000
MD
MD


Sample
Desc.
Marathon
CMF
lb/ton
lb/t
sht
ft2
g/3 in.
%





30.1
4882-28 754
50
50
20
0
29.5
9.1
2024
28.5


31-1
4882-29 814
50
50
20
3
26.5
9.3
2045
27.6


32-1
4882-30 833
50
50
20
3
27.4
9.8
2284
29.5


33-1
4882-31 850
50
50
20
3
29.0
10.1
2248
28.3


34-1 base
4882 - 32 915
50
50
20
e
26.7
8.1
1487
27.1


35-1 base
4882-33 941
50
50
20
6
26.4
8.9
1659
28.9


36-1 base
4882 - 34 1000
50
50
20
6
27.0
9.5
1787
27.2


37.1 base
4882 - 35 1018
50
50
23
7
22.8
7.0
882
25.7


38-1 base
4882 - 36 1035
50
50
23
7
23.4
7.0
1036
27.2


39.1 base
4882-37 1057
50
50
23
7
24.7
7.0
989
27.8
























CD Wet












Tens
Break
TEA
TEA
Break
Break




Tensile
Stretch
Tensile
Finch
Modulus
CD
MD
Mod.
Mod.




CD
CD
GM
Cured-
GM
mm-g/
mm-g/
CD
MD
Wet/


Sample
g/3 in.
%
g/3 in.
g/3 in.
g/%
mm2
mm2
g/%
g/%
Dry





30.1
831
7.7
1296
164
91
0.503
2.772
111
74
0.20


31-1
744
7.1
1233
180
88
0.420
2.305
104
74
0.24


32-1
851
6.8
1393
216
100
0.442
2.669
127
79
0.25


33-1
927
7.9
1444
235
97
0.568
2.591
118
80
0.25


34-1 base
573
7.4
921
154
67
0.327
1.803
BO
56
0.27


35-1 base
604
8.0
1000
177
68
0.379
1.876
BO
59
0.29


36-1 base
706
8.2
1121
157
73
0.472
2.062
82
65
0.22


37.1 base
462
8.1
649
125
44
0.314
1.215
58
34
0.26


38-1 base
444
7.5
677
114
48
0.250
1.329
59
39
0.26


39.1 base
444
8.8
662
105
42
0.315
1.265
51
35
0.24
















TABLE 5







Converted Product Construction




















Caliper
Basis






Break
FQA




8 Sheet
Weight
Tensile
Stretch
Tensile
Stretch
Tensile
Wet
Modulus
Fiber



Descrip-
mils/8
lb/3000
MD
MD
CD
CD
GM
Tens
GM
Count



tion
sht
ft2
g/3 in.
%
g/3 in.
%
g/3 in.
g/3 in.
g/%
Number





















Condition 1
4882 - 32
26.65
8.14
1487
27.1
573
7.4
921
206
66.83
435


Average
4882 - 33
26.35
8.92
1659
28.9
604
8.0
1000
165
68.38
494



4882 - 34
27.73
9.45
1787
27.2
706
8.2
1121
201
72.79
468




26.91
8.84
1644
27.72
627
7.86
1014
190.48
69.33
466


Condition 2
4882 - 35
22.78
6.98
882
25.7
482
8.1
649
138
43.97
383


Average
4882 - 36
23.43
7.03
1036
27.2
444
7.5
677
123
47.88
363



4882 - 37
24.68
7.00
989
27.8
444
8.8
662
132
42.25
305




23.63
7.00
969
26.89
456
8.15
663
130.85
44.70
350









When tested for physical properties, Dry Linting and Wet Abrasion Resistance, as set forth above, the results set forth in Table 6 were obtained:










TABLE 6









Base Sheet
Base Sheet



Condition 1
Condition 2












Cell 1
Cell 2
Cell 3
Cell 4


Description
2-Ply
3-Ply
2-Ply
3-Ply














Basis Weight (lbs/ream)
17.14
26.11
13.93
20.45


Caliper (mils/8 sheets)
60.28
108.00
55.58
88.41


MD Dry Tensile (g/3 in.)
2198
3528
1384
2507


CD Dry Tensile (g/3 in.
1069
1662
793
1133


Geometric Mean Tensile (g/3 in.)
1533
2420
1047
1683


MD Stretch (%)
16.70
19.14
16.74
18.94


CD Stretch (%)
7.43
7.47
7.59
8.35


Perforation Tensile (g/3 in.)
866
1380
652
972


Wet Tensile (g/3 in.)
311
477
213
332


GM Break Modulus (g/% strain)
137.56
202.50
93.92
134.23


MB 3100 Brightness (%)
92.12
92.25
92.15
91.71


MB 3100 b*
2.26
2.35
2.06
2.34


Opacity
73.98
82.39
67.12
76.09


Wet Abrasion FQA Lint Count
500
495
346
444


Dry Lint L * Difference
−0.26
−0.37
−0.43
−0.43


TMI Fric GMMMD 4 Scan-W
0.47
0.49
0.38
0.49


(Unitless)


Sensory Softness
17.22
17.61
18.29
18.47









Dry Lint: No data is shown in Table 4 for dry linting of the base sheets as the finished product. Dry-lint metrics as shown in Table 6 are all negative, indicating that the lint on the black felt was under the non-detect limit of the scanner. If it is taken that no dry lint was observed for the finished product, then it is extremely likely that the lint from the base sheets would similarly be under the detection limit.
Wet Abrasion Lint: At the time this data was collected, we were still in the process of developing a quantitative wet lint test, and so we used a qualitative wet abrasion test based on digital pictures taken to show the lint left behind prior to washing the sample for quantitative—FQA—testing that we were considering at that time. Accordingly, no statistical analysis was conducted to compare the linting of the CMF prototypes to the commercial products. From a comparison of FIGS. 6A-6D, however, it can be appreciated that Quilted Northern® Ultra Plush (FIG. 6A) and Quilted Northern® Soft & Strong (FIG. 6C) left behind large amounts of lint as compared to the two sheets containing 50% CMF which were, however, deemed not sufficiently dispersible, as it was determined that in excess of 2000 shakes would be required to disperse these sheets—if they could be dispersed at all.
Softness: The softness scores of the four prototypes are set forth in FIG. 7. It is apparent that cells 3 and 4 made from condition 2 base sheet are softer than cells 1 and 2. These two are also softer than Quilted Northern® Soft & Strong, Assignee's premium two-ply product, but not as soft as Quilted Northern® Ultra Plush, Assignee's Ultra Premium three-ply product, but are far stronger than either.
Example 2
Based upon the results from Example 1, it was determined to evaluate whether product designs satisfying the criteria of low lint, high softness, and dispersibility could be achieved using 20 to 50% CMF, 3 to 7 lb/t FJ98, and 7 to 8.5 lb/ream basis weight.
It was further determined that three-ply glue lamination was an unexpectedly desirable converting configuration for CMF sheets, as unexpectedly high caliper was obtained out of low basis weight sheets. Accordingly, basesheets were made having the properties set forth in Table 7 using CWP technology. When converted into finished three-ply glue laminated rolls, as set forth in Table 8, the products had the physical properties set forth in Table 9. While these products achieve significantly improved levels of softness, strength and resistance to linting whether wet or dry, it can be appreciated that none of those presented so far has met the ultimate goal of producing a tissue that is as soft as the softest available commercial tissues, but has sufficient resistance to wet linting to be usable pre-moistened.







TABLE 7







Basesheet Properties




































Cured-


















Wet












8 Sheet





Tens


GM









Caliper
BW
MD

CD

Finch
Disp.
GM
Break









mils/8
lb/3000
Tensile
MD
Tensile
CD
CD
# of
Tensile
Modulus


Cell
Roll
Cell
CMF
FJ98
BW
SW
sht
ft2
g/3 in.
Stretch
g/3 in.
Stretch
g/3 in.
Shakes
g/3 in.
g/%


























3
4885-12
4
25
4
9
50
30.0
9.2
775
26.5
384
5.3
98
800
545
47



4885-13
4
25
4
9
50
31.5
9.4
834
23.2
384
4.9
104
800
563
53



4885-14
4
25
4
9
50
28.7
8.7
716
24.8
340
5.8
95
800
493
41



Average





30.1
9.1
775
24.8
369
5.3
99
800
534
47


4
4885-33
7
50
4
9
50
27.8
8.06
658
25.3
349
6.8
76

479
37



4885-34
7
50
4
9
50
29.9
8.74
905
27.8
386
6.8
83
500
591
42



4885-35
7
50
4
9
50
32.6
9.76
1074
27.6
423
6.1
95
600
673
51



Average





30.1
8.9
879
26.9
386
6.6
84
550
581
43
















TABLE 8







Converted Product Construction












cell
Front Roll
Middle Roll
Back Roll







3
4885-12
4885-13
4885-14



4
4885-34
4885-33
4885-35

















TABLE 9







part 1, Converted Product Physical Properties




















Dispers-
Lint
Basis
Caliper




CD Wet
Break




ibility
Black
Weight
8 Sheet
MD
CD
MD
CD
Tens
Modulus



Softness
# of
Felt
lb/3000
mils/8
Tensile
Tensile
Stretch
Stretch
Finch
GM


Description
Panel
Shakes
Unitless
ft2
sht
g/3 in.
g/3 in.
%
%
g/3 in.
g/%





Cell 3, 3-ply
18.7
713
1.92
24.9
164
1011
672
11.8
7.0
140
92


Cell 3, 3-ply
18.7
663
1.73
25.1
158
1063
651
13.0
6.5
149
90


Cell 4, 3-ply
18.6
788
0.35
24.4
160
1645
848
15.2
9.3
156
100


Cell 4, 3-ply
18.6
800
0.12
23.4
154
1478
844
15.6
9.1
157
97


Cell 3 Average
18.7
688
1.83
25.0
161
1037
662
12.4
6.8
144
91


Cell 4 Average
18.6
794
0.24
23.9
157
1561
846
15.4
9.2
156
98










part 2, Converted Product Physical Properties




























FQA




Opacity
TMI
Void
Break
Break

TEA
TEA
FQA
Fiber
FQA



MacBeth
Ply
Volume
Modulus
Modulus
Void
MD
CD
Fiber
Len
Fine



Opacity
Bond.
Wt
MD
CD
Volume
mm-gm/
mm-gm
Count
Lw
Len Lw



Units
g
Inc %
g/%
g/%
Ratio
mm2
mm2
Number
mm
%





Cell 3, 3-ply
79
10.9
1,353
88
97
7.2
0.76
0.37
2408
0.80
9.0


Cell 3, 3-ply
80
6.5
1,399
82
99
7.4
0.94
0.33
2011
0.79
9.1


Cell 4, 3-ply
82
7.6
1,399
108
93
6.9
1.65
0.61
1563
0.64
17.7


Cell 4, 3-ply
82
9.5
1,373
98
95
7.3
1.21
0.60
2985
0.78
10.4


Cell 3 Average
79
8.7
1376
85
98
7.3
0.85
0.35
2209
0.80
9.0


Cell 4 Average
82
8.5
1386
103
94
7.1
1.43
0.60
2274
0.71
14.0









Table 10 shows a comparison of converted low-lint CWP, CMF containing products with an ultra-premium retail tissue, Assignee's Quilted Northern® Ultra Plush and a competitive product which, judging from its name, is apparently promoted at least partially on the basis of its strength, Charmin® Ultra Strong. Three-ply CWP products with CMF were able to at least slightly surpass the performance of Charmin® Ultra Strong in several ways: higher bulk, higher wet strength, higher opacity, and much lower lint, achieving these advantages at equal weight and softness. The softness difference, however, is not sufficiently large, so that it is entirely certain that the difference could be replicated in subsequent panels testing the same products. It is clear, however, that the softness of the CMF containing protocepts was significantly inferior to that of Quilted Northern® Ultra Plush even though their bulk, wet and dry strength, opacity and linting resistance were improved.







TABLE 10







Comparison of Converted Product















Previous low-





Quilted
Charmin ®
lint protocept
Current
Current



Northern ®
Ultra
Comparative
25% CMF
50% CMF



Ultra Plush
Strong
Example 1
Protocept
Protocept
















CMF, %


50
25
50


SW, %


50
37.5
25


Euc, %


 0
37.5
25


FJ98, lb/t


20
4
4


Basesheet BW, lb/ream
12-12.5

7
9
9


Emboss


HVS-9 knurl
HVS-9 glue
HVS-9 glue


Caliper mils/8 sheet
144
140
88
161
157


Caliper, cc/g
7.8
11.4
  8.4
12.6
12.9


Void Volume, % increase

1,301

1,376
1,386


Basis Weight, lb/3000 ft2
36
23.9
  20.4
25.0
23.9


MDDT, g/3 in.
1200
1,373
2507 
1,037
1561


MD str, %

16.56
  18.9
12.4
15.4


CDDT, g/3 in.
450
699
1133 
662
846


CD Str, %

11.1
  8.4
6.8
9.2


CDWT, g/3 in.
40
79
332 
144
156


GMT, g/3 in
735
980
1685 
828
1149


GM Break Modulus,
59
73
134 
91
98


g/%/3 in.


Opacity
77
67

79
82


Softness
20.0
18.6
  18.5
18.7
18.6


Dispersibility, # of
<700

2000+ 
688
794


Shakes


Dry Lint (Delta L*)
10.2
3.0
  −0.4
1.8
0.24


Wet Lint (Fiber Count)
15000
8,480
444 
2209
2274









It can be appreciated that the protocept (trial product produced in the laboratory that may not necessarily be commercially or economically practical to manufacture in commercial equipment) with 25% CMF exhibited quite good levels of softness, linting, opacity, dispersibility and strength. The softest products, however, were somewhat deficient in softness compared to Quilted Northern® Ultra Plush.
Example 3
As the protocepts of Examples 1 and 2 were unable to match the softness performance of Assignee's ultra premium product, Quilted Northern® Ultra Plush, exploratory work was done using the paper-making technology disclosed in U.S. Patent Application Publication No. 2010/0186913, in conjunction with lower CMF content furnishes, to determine the possible interaction of this new belt-creping technology with CMF containing furnishes and to determine whether the two technologies were compatible, and, if so, whether the use of the two together had advantages in the formation of a pre-wettable bath tissue. It had been hoped that, if this effort were successful, it might be possible to develop a pre-wettable bath tissue that, even though it might not match Quilted Northern® Ultra Plush in absolute level of softness, might be close enough that any deficiency would not be easily perceptible. So, rather improved softness was desired to exceed the 18.7 panel softness achieved in Comparative Example 2 and more closely approach the Panel softness value of 20 achieved by Quilted Northern® Ultra Plush.
Accordingly, basesheet samples were prepared using a belt similar to that illustrated in FIG. 3 on a pilot scale paper machine using a furnish comprising 65% northern bleached softwood kraft, 15% eucalyptus, and 20% CMF with temporary wet strength with process parameters set as described in Table 11. The properties of those basesheets are set forth in Table 12. Using the scheme set forth in Table 13, the basesheets were converted into finished product, as set forth in Table 14, the properties of which, as determined by physical properties testing and sensory panels, are set forth in Table 15.
Table 16 sets forth the dispersibility, wet tensile strength and basis weight of several commercial products along with those of many products produced in this Example. See FIG. 29 as well.







TABLE 11





Process Data

































Form











Jet
Roll
Yankee
Reel



64551
64601
PVOH
GPB100
GP C
FJ98
Spd
Speed,
Speed,
Speed,


Roll#
lb/t
lb/t
lb/t
lb/t
lb/t
lb/t
fpm
fpm
fpm
fpm





22910
1.0
0.5
7.3
6.0
0.0
2.4
2633
1933
1601
1523


22911
1.0
0.5
7.3
5.8
0.0
3.0
2634
1933
1601
1523


22912
1.0
0.5
7.3
5.8
0.0
3.0
2634
1933
1601
1523


22918
1.3
0.6
9.0
7.1
0.0
3.7
2633
1933
1601
1523


22919
1.2
0.6
8.6
6.7
0.0
3.6
2633
1933
1601
1523


22920
1.2
0.6
8.5
6.6
0.0
3.7
2633
1933
1601
1523


22921
1.2
0.6
8.4
6.6
0.0
8.9
2633
1933
1601
1523


22922
1.2
0.6
8.4
6.9
0.0
9.0
2633
1933
1601
1523


22923
1.2
0.6
8.5
6.5
0.0
8.9
2632
1933
1601
1523


22928
1.2
0.6
7.8
4.8
0.0
14.4
2643
1939
1601
1523


22929
1.2
0.6
7.8
5.1
0.0
14.5
2644
1939
1601
1523


22931
1.2
0.6
7.9
4.9
0.0
14.5
2639
1939
1601
1523


22932
1.2
0.6
7.9
4.9
0.0
14.4
2639
1939
1601
1523


22933
1.2
0.6
7.9
5.0
0.0
14.4
2640
1939
1601
1523


22948
1.4
0.7
9.5
1.1
0.0
3.9
2430
1697
1401
1334


22949
1.4
0.7
9.7
0.9
0.0
4.0
2448
1697
1401
1332


22950
1.4
0.7
9.7
1.0
0.0
4.0
2480
1697
1401
1333


22960
1.0
0.5
6.3
2.1
0.0
2.8
2565
1939
1601
1523


22961
1.0
0.5
6.3
2.5
0.0
2.7
2565
1939
1601
1523


22966
1.5
0.8
10.0
2.7
0.0
2.2
2526
1939
1601
1523


22968
1.5
0.8
10.0
2.8
0.0
2.2
2515
1939
1601
1523


22969
1.5
0.8
10.0
2.8
0.0
2.2
2515
1939
1601
1523


22973
1.4
0.7
9.5
2.9
0.6
2.1
2514
1939
1601
1523


22974
1.4
0.7
9.5
3.3
0.7
2.0
2514
1939
1601
1523


22975
1.4
0.7
9.5
2.8
0.9
2.0
2514
1939
1601
1523


22981
1.0
0.5
6.2
1.8
4.1
2.1
2619
1939
1601
1523


22982
1.3
0.6
3.8
2.8
6.3
2.5
2619
1939
1601
1262
























WE
DE








Total

Yankee
Yankee
Suction
Molding




Jet/
Slice
HB

Hood
Hood
roll
Box
ViscoNip



Wire
Opening
Flow,
Refiner
Temp.,
Temp.,
vacuum,
Vacuum,
Load,


Rolls
Ratio
inches
gpm
HP
F.
F.
in. Hg.
in. Hg.
PLI





22910
1.36
0.779
1727
14.7
430
381
11.4
11.1
558


22911
1.36
0.779
1731
14.7
392
342
11.5
11.1
600


22912
1.36
0.779
1729
14.7
392
338
11.5
11.2
600


22918
1.36
0.779
1737
34.6
323
205
11.2
12.0
600


22919
1.36
0.779
1733
34.7
325
203
11.3
12.2
600


22920
1.36
0.779
1733
34.8
328
202
11.3
12.2
600


22921
1.36
0.779
1733
34.8
326
201
11.3
12.3
600


22922
1.36
0.779
1731
34.8
325
200
11.4
12.3
600


22923
1.36
0.779
1728
33.7
325
200
11.4
12.4
600


22928
1.36
0.767
1698
35.3
348
192
11.7
12.2
600


22929
1.36
0.767
1698
35.4
353
193
11.7
12.2
600


22931
1.36
0.774
1696
35.5
352
194
11.8
12.1
600


22932
1.36
0.775
1701
35.6
344
195
11.8
21.7
600


22933
1.36
0.775
1700
35.4
350
195
11.8
23.2
600


22948
1.43
0.753
1307
10.3
419
378
11.8
19.5
375


22949
1.44
0.753
1312
10.3
393
338
11.7
24.2
375


22950
1.46
0.753
1332
10.3
399
347
11.7
24.3
375


22960
1.32
0.876
2307
10.1
598
558
11.7
23.6
600


22961
1.32
0.876
2308
10.1
602
546
11.8
23.7
600


22966
1.30
0.876
2252
31.2
398
343
11.2
22.7
600


22968
1.30
0.876
2235
34.2
398
353
10.6
22.8
600


22969
1.30
0.876
2242
35.3
396
343
10.6
22.8
600


22973
1.30
0.910
2242
22.5
401
341
10.8
23.0
600


22974
1.30
0.910
2242
22.5
399
358
10.8
23.1
600


22975
1.30
0.910
2239
22.4
399
345
10.8
23.1
600


22981
1.35
0.753
1564
10.1
600
548
11.7
23.9
350


22982
1.35
0.753
1569
10.0
602
551
11.9
20.7
350
















TABLE 12







Basesheet Data






















TL2009-
Base

8 Sheet
Basis





Finch
Break
TEA

Void
Lint


2041
sheet

Caliper
Weight
Tensile
Stretch
Tensile
Stretch
Tensile
CD
Modulus
GM

Volume
Black


Parent
CMF
FJ98,
mils/8
lb/3000
MD
MD
CD
CD
GM
g/3
GM
mm-gm/

Wt
Felt


Roll
%
lb/ton
sht
ft2
g/3 in.
%
g/3 in.
%
g/3 in.
in.
g/%
mm2
W/D
Inc. %
Unitless

























22910
20
2.4
54.5
9.0
359
30.4
260
8.2
306
30
19.4
0.289
0.11
999
2.94


22911
20
3.0
53.7
9.1
399
31.3
263
7.9
324
34
20.7
0.308
0.13
1,093
2.68


22912
20
3.0
52.3
8.6
341
29.1
289
8.1
314
41
19.7
0.293
0.14
1,013
2.51


22918
20
3.7
39.9
7.1
361
27.2
286
7.6
321
40
21.8
0.285
0.14
1,084
1.00


22919
20
3.6
42.5
7.2
392
26.8
307
8.0
347
41
23.6
0.295
0.13
1,103
0.58


22920
20
3.7
40.1
7.1
414
28.0
309
7.1
358
42
25.7
0.309
0.14
1,075
0.71


22921
20
8.9
41.6
7.2
510
27.2
401
7.0
452
90
33.2
0.390
0.22
1,010
0.51


22922
20
9.0
40.2
7.3
493
26.0
409
7.9
449
91
31.0
0.409
0.22
971
0.20


22923
20
8.9
40.6
7.3
526
26.2
384
7.1
450
83
33.0
0.380
0.22
1,020
0.33


22928
20
14.4
41.8
7.4
632
28.5
517
7.4
571
144
39.8
0.531
0.28
938
0.02


22929
20
14.5
41.4
7.2
591
27.7
503
8.1
544
160
37.5
0.533
0.32
922
−0.17


22931
20
14.5
43.4
7.3
643
28.8
481
7.9
556
139
37.1
0.541
0.29
908
0.12


22932
20
14.4
47.6
7.2
577
27.1
425
7.4
494
136
35.0
0.443
0.32




22933
20
14.4
47.1
7.2
545
26.6
464
8.0
503
144
34.9
0.476
0.31




22948
20
3.9
69.7
12.1
663
35.0
347
11.0
479
71
24.9
0.542
0.20




22949
20
4.0
74.0
12.0
662
32.6
376
10.1
498
57
27.5
0.529
0.15




22950
20
4.0
71.7
11.9
662
33.5
414
9.9
523
82
28.9
0.554
0.20




22960
0
2.8
83.0
14.8
496
22.8
394
5.2
442
45
41.1
0.251
0.11




22961
0
2.7
84.2
14.7
531
24.1
461
6.1
495
63
40.0
0.395
0.14




22966
0
2.2
57.4
8.9
321
22.7
260
7.1
289
25
23.0
0.239
0.10




22968
0
2.2
55.7
9.0
353
20.5
285
6.2
317
30
28.5
0.237
0.10




22969
0
2.2
57.7
9.1
324
19.6
294
6.4
308
26
27.5
0.230
0.09




22973
10
2.1
56.0
9.2
410
22.9
272
4.8
333
24
32.2
0.229
0.09




22974
10
2.0
57.3
9.7
495
24.1
399
6.4
444
33
36.2
0.357
0.08




22975
10
2.0
56.1
9.7
434
23.6
347
6.3
388
33
32.1
0.310
0.10




22981
10
2.1
82.8
14.6
451
27.6
272
5.7
350
45
28.5
0.010
0.17




22982
10
2.5
78.7
14.7
530
30.3
297
5.5
396
48
29.9
0.005
0.16
















TABLE 13







Basesheet Configuration












Cell
Marathon/Euc/CMF
Basis wt.
FJ98, lb/t
Notes
Parent rolls















1
65/15/20
9
Low
Softest
22910, 22911, 22912


2
65/15/20
7
Low
Some durability
22918, 22919, 22920


3
65/15/20
7
Med.
More durable
22921, 22922, 22923


4
65/15/20
7
High
Most durable
22928, 22929, 22931


5
65/15/20
7
High
Aperture
22932, 22933


6
65/15/20
15
Low
Ultra
22948, 22949, 22950


7
35/65/zero
15
Low
Ultra 2-ply Control
22960, 22961


8
35/65/zero
9
Low
Ultra 3-ply Control
22966, 22968, 22969


9
35/65/10
9
Low
Ultra 3-ply
22973, 22974, 22975


10
35/65/10
15
Low
Ultra 2-ply
22981, 22982
















TABLE 14







Converting Configuration













#1 Unwind
#2 Unwind
#3 Unwind
Product



Cell No.
Base Sheet
Base Sheet
Base Sheet
Description
Converting Process





P3403
22910
22911
22912
Wet durable
“K” = 3-Ply Unembossed, knurled; “G” = 3-ply HVS U19, glued


P3404
22918
22919
22920
Wet durable
“K” = 3-Ply Unembossed, knurled; “G” = 3-ply HVS U19, glued


P3405
22921
22922
22923
Wet durable
“K” = 3-Ply Unembossed, knurled; “G” = 3-ply HVS U19, glued


P3406
22928
22929
22931
Wet durable
“K” = 3-Ply Unembossed, knurled; “G” = 3-ply HVS U19, glued


P3407
22932
22949
22933
Wet durable,
“K” = 3-Ply Unembossed, knurled






aperture*


P3408
22948
22949
22950
Ultra
“K” = 3-Ply Unembossed, knurled; “G” = 3-ply HVS U19, glued


P3409
22948
22949

Ultra
“K” = 2-Ply Unembossed, knurled; “G” = 2-ply HVS U19, glued


P3410
22932
22911
22933
Wet durable,
“K” = 3-Ply Unembossed, knurled






aperture*


P3411
22960
22961

Ultra
“K” = 2-Ply Unembossed, knurled; “G” = 2-ply HVS U19, glued


P3412
22966
22968
22969
Ultra
“K” = 3-Ply Unembossed, knurled; “G” = 3-ply HVS U19, glued


P3413
22973
22974
22975
Ultra
“K” = 3-Ply Unembossed, knurled; “G” = 3-ply HVS U19, glued


P3415
22981

22982
Ultra
“K” = 2-Ply Unembossed, knurled; “G” = 2-ply HVS U19, glued


P3416
22981
22960
22982
Ultra
“K” = 3-Ply Unembossed, knurled; “G” = 3-ply HVS U19, glued





*aperture basesheet -- a very open, porous construction similar to that shown in FIG. 1 of US 2004/0238135, but heavier.













TABLE 15







Finished Product Data















Basis
Caliper


Wet Tens
Dry Lint
Dispers-



Weight
8 Sheet
Softness
Tensile GM
Finch CD
BlackFelt
ibility


Descrip-
lb/3000 ft2
mils/8 sheet
Panel
g/3 in.
(g/3 in.)
(ΔL*)
#shakes





















tion
Knurled
Glued
Knurled
Glued
Knurled
Glued
Knurled
Glued
Knurled
Glued
Knurled
Glued
Knurled
Glued










Wet Durable





















P3403
26.7
26.3
152
145
20.1
19.3
841
932
104
113
4.0
5.4
600
600


(20% CMF)
















P3404
21.9
21.7
117
115
19.5
18.6
1,060
1,155
139
152
0.8
1.1
575
550


(20% CMF)
















P3405
22.4
21.6
121
114
19.2
18.2
1,409
1,394
268
281
0.4
0.8
1,600
2,000


(20% CMF)
















P3406
23.1
22.3
125
119
18.7
17.9
1,719
1,672
439
432
−0.1
0.5
3,700
3,600


(20% CMF)
















P3407
27.4

161

18.9

1,406

321

0.2

2,800



(20% CMF)
















P3410
24.2

141

19.2

1,312

287

0.2

1,800



(20% CMF)





















3-Ply Ultra, I.C. and Parity





















P3412
28.1
27.5
166
155
19.2
18.7
903
946
86
86
2.3
2.4




(no CMF)
















P3413
29.4
28.8
168
157
19.5
18.3
1129
1,169
113
103
1.9
2.3




(10% CMF)





















3-Ply Ultra, Superior





















P3416
45.2
43.9
236
204
19.7
18.9
1164
1,218
163
141
7.4
7.6




(13% CMF)





















2-ply Ultra





















P3411
30.7
31.0
151
154
19.2
18.5
917
909
117
101
4.5
6.2




(no CMF)
















P3415
29.7
29.2
152
150
19.7
19.3
706
700
91
90
7.2
5.8




(10% CMF)





















Other





















3-ply P3408
37.1
35.1
206
179
19.6
18.0
1,434
1,714
226
274
4.4
5.2




(20% CMF)
















2-ply P3409
24.6
24.0
134
132
19.3
18.7
973
973
155
154
4.6
4.2




(20% CMF)





Knurled product is Unembossed. Glued product is embossed with U19
















TABLE 16







CD Wet Tensile




Dispersibility
Finch
Basis weight,


Description
# of Shakes
(gms/3-in.)
lb/3000 ft2


















P3403K
600
104
26.7


P3404K
575
139
21.9


P3405K
1600 
268
22.4


P3406K
3700 
439
23.1


P3407K
2800 
321
27.4


P3410K
1800 
287
24.2


P3403G
600
113
26.3


P3404G
550
152
21.7


P3405G
2000 
281
21.6


P3406G
3600 
432
22.3


Charmin ® Ultra Soft
400
71
29.0


Quilted Northern ® Ultra Plush
850
40
36.0


Cottonelle ® Ultra Ave
 56
23
27.7


Charmin ® Ultra Soft Ave
349
61
28.9


Charmin ® Ultra Strong Ave
297
69
24.4


QUILTED NORTHERN ® ULTRA
997
42
36.8


Charmin ® Basic Ave
250
53
18.0


Cottonelle ® Fresh
20000+ 
710
48.0









The results, as set forth in Table 15, were considered unexpectedly good—especially in terms of softness. It was surprisingly found that not only was it possible to achieve close parity to Quilted Northern® Ultra Plush, but that, in one case, at least numerical superiority was achieved even though the margin of superiority was slight. Table 10, above, shows properties of an ultra-premium retail tissue, Assignee's Quilted Northern® Ultra Plush, and a competitive product that is apparently promoted at least partially on the basis of its strength, Charmin Ultra Strong. Several knurled three-ply CWP products with CMF of this example were able to surpass the performance of Charmin® Ultra Strong in several ways: softness, higher bulk, higher wet strength, higher opacity, and much lower lint achieving these advantages at equal weights. The softness difference for P3406K, however, is not sufficiently large that it is entirely certain that the difference could be replicated in subsequent panels testing the same products. (Typically, we find that an improvement of 0.5 points of softness on the scales reported by our sensory panels will consistently be considered distinctly and noticeably softer.) The softness of the glued products was lower than what we would normally expect in comparison to the knurled. The reason for this deficiency is not known, but could easily lie more in the embossing and gluing techniques used rather than in the basesheets themselves. Even more surprisingly, it was found that the strength of P3403K was actually significantly higher than that of Quilted Northern® Ultra Plush, even though the basis weight of the softer, but stronger sheet, was less than 75% of Quilted Northern® Ultra Plush. Further, the sheet was dispersible, but exhibited sufficient wet strength to be usable pre-wetted. In terms of dry lint, this product also surpassed Quilted Northern® Ultra Plush, exhibiting a ΔL* of 4.0 as compared to 10.2 for Quilted Northern® Ultra Plush.
FIGS. 8A to 8D provide graphic comparisons of the most significant properties of the tissues to Quilted Northern® Ultra Plush, Quilted Northern® Soft & Strong, Charmin® Ultra Soft and Charmin® Ultrastrong.
FIG. 8A demonstrates that P3403K, the wet linting of which is shown in FIG. 9A, is comparable in softness to Quilted Northern® Ultra Plush and Charmin® Ultra Soft, both of which currently are generally perceived as having very high softness by Assignee's sensory softness testing panels, while a comparison of FIGS. 9A and 9C demonstrates that Charmin® Ultra Soft is quite susceptible to wet linting, indicating that it would not generally be considered to be satisfactory for use pre-moistened, while P3405K leaves behind far less lint and so might be deemed to be acceptable for that use. FIG. 8A also illustrates that the dry linting of P3403K is somewhat less than that of either Charmin® Ultra Soft or Quilted Northern® Ultra Plush, which are not perceived as having significant quality issues in this regard. The comparison shown in FIGS. 9A to 9E visually portrays the qualitative results that considerable lint is left on the felt with the two Charmin® products, a much smaller, but detectable amount of lint is left behind with P3403K, while it is quite difficult to detect lint left behind with either P3405K or the Kimberly-Clark Cottonelle® Fresh. It is considered quite significant that P3405K achieves softness clearly exceeding that of Charmin® Ultra Strong, while leaving almost no lint behind on either of the wet linting test or the dry. See FIG. 9B. Quilted Northern® Ultra Plush and Quilted Northern® Soft & Strong are roughly comparable in wet linting to the two Charmin® products. FIG. 8B illustrates that P3403K achieves Total Energy Absorption, (TEA, a measure of toughness), equivalent to Charmin® Ultra Soft while P3405K, in addition to its remarkable resistance to linting, clearly surpasses Charmin® Ultra Strong both in toughness and softness. FIG. 8C illustrates the same advantages in term of tensile strength rather than toughness. FIG. 8D compares the fiber required for a statistical case among the various tissues examined, although it should be noted that this does not translate into savings due to the increased cost of the CMF as compared to wood pulp. Preliminary testing, done before the procedures for measuring dispersibility and wet lint were developed, indicated that high linting products, such as the two Charmin® tissues, were quite easily dispersed, as were the very soft products P3403G and P3403K, which exhibited moderate linting. The very low lint CMF containing products of this Example could be dispersed without undue difficulty, while the non-wovens, Cottonelle® Fresh and Always were far more difficult to disperse, if dispersible at all.
Example 4
In an attempt to improve upon earlier wet-durable tissue made with the belt of FIG. 3, bath tissue was made with cellulose microfiber (CMF) and temporary wet strength using the belt shown in FIGS. 10 and 11. Table 17 below sets forth important parameters of the belt construction.







TABLE 17







Belt Geometry









Parameters
Units
Dimensions












Sheet Side Hole CD Diameter
mm
0.9652


Sheet Side Hole MD Diameter
mm
0.9652


Sheet Side Hole CD/MD
CD/MD (unitless)
1.0


Sheet Side Hole Unit Area
mm2
0.732


Top Hole Rim Thickness
mm


Sheet Side Hole % Open Area
%
52.7


Air Side Hole CD Diameter
mm
0.5461


Air Side Hole MD Diameter
mm
0.5461


Air Side Hole CD/MD
CD/MD (unitless)
1.00


Air Side Hole Unit Area
mm2
0.234


Air Side Hole % Open Area
%
16.9


Sheet Side/Air Side Area Ratio
Top/Bottom
3.1


Side Wall Angle CD 1
° (Degrees)
67.3


Side Wall Angle CD 2
° (Degrees)
67.3


Side Wall Angle MD 1
° (Degrees)
67.3


Side Wall Angle MD 2
° (Degrees)
67.3


Unit Volume
mil3
15863


Unit Volume
mm3
0.260


% Material Volume Removed
%
 37.5%


MD Land Distance
mm
1.3016


MD Land/MD Dia. Ratio
%
134.9%


CD Land Distance
mm
0.2589


CD Land/CD Dia. Ratio
%
26.82%


1./width
Columns/cm
8.17


1/height
Rows/cm
8.82


Holes per cm2
#/cm2
72









Basesheets were made using generally those procedures used in Example 3. Basesheet properties are set forth in Table 18.







TABLE 18







Basesheet
























CD Wet






8 Sheet
Basis




Tens

GM
CD



Caliper
Weight
MD
MD
CD
CD
Finch
GM
Break
Tensile


Descrip-
mils/8
lb/3000
Tensile
Stretch
Tensile
Stretch
Cured
Tensile
Modulus
Wet/Dry


tion
sht
ft2
g/3 in.
%
g/3 in.
%
g/3 in.
g/3 in.
gms/%
Unitless




















24482
48.7
8.0
467
31.8
374
9.5
104
418
24.3
0.28


24483
50.2
8.0
508
31.2
390
9.1
98
445
26.1
0.25


24484
47.0
8.0
507
30.7
387
9.5
98
443
26.3
0.25


24496*
88.1
13.7
483
33.9
360
6.0
85
417
29.7
0.24


24499
73.6
13.5
595
29.8
444
5.4
113
513
40.3
0.25


24500
71.7
13.9
490
29.0
403
6.5
89
444
32.7
0.22


24501
71.1
13.6
527
28.3
462
6.4
108
493
35.5
0.23





*uncalendered






These products were converted into three-ply tissue product using the converting scheme set forth in Table 19, the finished tissue having the properties set forth in Table 20.







TABLE 19







(U19 Glue Laminated)












Front
Middle

Many Roll Nip

Roll


Roll #
Roll #
Back Roll #
Open/Closed
Caliper
Diameter





24482
24483
24484
open
134
4.9


24500
24483
24484
open
153
4.9


24500
24496
24483
open
180


24499
24501

open
132


24499
24501

open


24482
24483
24484


24496
24483
24484
















TABLE 20







Finished Product Properties

























CD Wet











Basis
8 Sheet

Lint
Tens




GM
Opacity





Weight
Caliper
Tensile
Black
Finch

Dispers.
MD
CD
Break
MacBeth
Sheet
Sheet



lb/3000
mils/8
GM
Felt
Cured-
Softness
# of
Tensile
Tensile
Modulus
Opacity
Length
Width


Cell
ft2
sht
g/3 in..
Unitless
g/3 in.
Panel
Shakes
g/3 in.
g/3 in..
g/%
Units
in
in























1
24.5
142
1,417
1.1
342
18.4
2,500
1,606
1,251
92.3
75.4
4.1
4.0


2
29.5
158
1,229
1.2
269
18.6
2,100
1,475
1,027
90.4
79.1
4.1
4.1


3
34.9
184
1,261
1.5
275
18.0
3,200
1,508
1,059
102.9
81.6
4.2
4.1


4
26.6
135
962
2.3
222
17.7
2,000
1,130
819
80.3
76.3
4.2
4.1


5
24.0
136
1,412
0.6
315
18.5
1,500
1,591
1,255
92.7
75.1
7.3
4.8


6
29.1
161
1,315
1.3
293
18.6
1,500
1,510
1,145
97.9
78.5
7.4
4.8


8
26.5
137
913
2.2
208
17.6
1,500
1,064
785
75.2
75.9
7.4
4.8









Even though the bath tissue of Example 3 made using the belt described and illustrated in FIG. 3 had a desirable combination of softness, wet durability, and low lint, achieving both premium softness as a dry tissue and sufficient wet tensile to be used for wet cleansing without pilling, the amount of temporary wet strength resin in the sheets was quite high, ranging up to 14 lb/ton resulting in a finished product with a wet tensile up to 439 g/3 in. Accordingly, we wished to investigate whether we could achieve satisfactory properties with a more moderate level of temporary wet strength resin.
Several adjustments were made relative to the preceding trial. Basis weight was increased slightly, eucalyptus was increased in the Yankee layer, stretch was increased, and bulky fiber was added to the air layer (for stratified conditions). Basesheets at 7 lb/ream using the belt of FIG. 3 had caliper around 40 mil/8 sheets, and three-ply product had caliper around 120 mil/8 sheets. Increasing basis weight to 8 lb/ream was intended to get basesheet caliper into the upper 40's and finished product around 145 mil/8 sheets. The previous low-lint furnish comprising 60% NBSK, 15% eucalyptus, and 20% CMF yielded very low lint when combined with higher levels of temporary wet strength. In this Example 4, eucalyptus content was increased to 40%, to impart an even smoother surface, while maintaining low lint. Higher crepe was used to lower modulus. Hardwood BCTMP was used in the air layer in one cell for additional bulk. A glue-laminated three-ply prototype was made with a very desirable combination of softness, wet strength, and low pilling tendency: 18.4 softness panel rating, 342 g/3 in. CD wet tensile, 1.1 ΔL* dry lint. FIGS. 12 and 13 present the results of cell 5 of this Example 4 along with data from the previous Examples. It can be appreciated that the CD wet tensile is still quite high—ranging from 208 to 342, so even though these sheets had excellent softness, there is still the possibility of achieving higher softness by going to lower CD wet tensile as for most of these sheets. That works out to between 10 and 13 g/3 in. per pound of basis weight and we have discovered that about 8.5 g/3 in. per pound of basis weight is sufficient to render these CMF containing sheets usable pre-wetted.
FIGS. 21 to 23 illustrate domed structures having consolidated regions formed therein. FIG. 21 is an SEM section (75×) along the machine direction (MD) of perforated polymeric belt creped basesheet 600, showing a domed area corresponding to a belt perforation as well as the densified pileated structure of the sheet. It is seen in FIG. 21 that the domed regions, such as region 640, have a “hollow” or domed structure with inclined and at least partially densified sidewall areas, while surrounding areas 618, 620 are densified, but less so than transition areas. Sidewall areas 658, 660 are inflected upwardly and inwardly and are so highly densified as to become consolidated, especially, about the base of the dome. It is believed that these regions contribute to the very high caliper and roll firmness observed. The consolidated sidewall areas form transition areas from the densified fibrous, planar network between the domes to the domed features of the sheet and form distinct regions that may extend completely around and circumscribe the domes at their bases, or may be densified in a horseshoe or bowed shape only around a portion of the bases of the domes. At least portions of the transition areas are consolidated and also inflected upwardly and inwardly.
FIG. 22 is another SEM (120×) along the MD of basesheet 600 showing hollow 640, as well as consolidated sidewall areas 658 and 660. It is seen in this SEM that the cap 662 is fiber-enriched, of a relatively high basis weight as compared with areas 618, 620, 658, 660. CD fiber orientation bias is also apparent in the sidewalls and dome.
FIG. 23 is an SEM section (120×) along the machine direction (MD) of basesheet 700, in which consolidated sidewall areas 758, 760 are densified and are inflected inwardly and upwardly.
As illustrated in FIG. 24, the process for producing high lignin eucalyptus by pre-conditioning refiner chemical alkaline peroxide mechanical pulping consists of five main process steps:
1. Impregnation: Wood chips (or plant fibers) are compressed in a large screw press and discharged into an inclined (atmospheric) impregnation vessel. The vessel contains a mixture of chelant, hydrogen peroxide and caustic. The chemicals soften the chips and begin the bleaching process.
2. High Consistency Pressurized Refining: The impregnated chips drain as they are lifted out of the impregnation vessel and are fed through a high consistency refiner. The refiner separates the chips into individual fibers and provides heat to drive the bleaching reactions. Hydrogen peroxide is injected into the refiner discharge to boost the brightness. The hot pulp is discharged into an atmospheric tank and achieves full brightness after 30 to 90 minutes of retention.
3. Low consistency secondary refining: A final refining pass is done at low consistency to develop the desired fiber properties and to complete fiberization of any shives.
4. Shive Screening: The pulp is screened to separate shives from the fully individualized fibers. The rejects are fed back into the low consistency refiner to complete separation into individual fibers.
5. Washing: A tissue grade system would use three stages of presses to separate residual bleaching chemicals and anionic trash formed in the process.
For further information concerning pre-conditioning refiner chemical alkaline peroxide mechanical pulping, see:
Xu, U.S. Patent Application Publication No. 2010/0263815 A1, now U.S. Pat. No. 8,216,423, “Multi-Stage AP Mechanical Pulping With Refiner Blow Line Treatment”, Oct. 21, 2010; Herkel et al., U.S. Patent Application Publication No. 2010/0186910 A1, now U.S. Pat. No. 8,048,263, “Four Stage Alkaline Peroxide Mechanical Pulpings”, Jul. 29, 2010; Sabourin, U.S. Patent Application Publication No. 2008/0066877 A1, now U.S. Pat. No. 7,758,720, “High Defiberization Pretreatment Process For Mechanical Refining”, Mar. 20, 2008; Herkel, U.S. Patent Application Publication No. 2004/0200586 A1, “Four Stage Alkaline Peroxide Mechanical Pulping”, Oct. 14, 2004; Sabourin, U.S. Pat. No. 7,892,400 B2, “High Defiberization Chip Pretreatment Apparatus”, Feb. 22, 2011; Sabourin, U.S. Pat. No. 7,758,721 B2, “Pulping Process With High Defiberization Chip Pretreatment”, Jul. 20, 2010; Sabourin, U.S. Pat. No. 7,300,541 B2, “High Defiberization Chip Pretreatment”, Nov. 27, 2007; Sabourin, U.S. Pat. No. 6,899,791 B2, “Method Of Pretreating Lignocellulose Fiber-Containing Material In A Pulp Refining Process”, May 31, 2005; Xu, U.S. Patent Application Publication No. 2004/0069427 A1, “Multi-Stage AP Mechanical Pulping With Refiner Blow Line Treatment”, Apr. 15, 2004; and Xu et al., International Publication No. WO 03/008703 A1; “Four Stage Alkaline Peroxide Mechanical Pulping”, Jan. 30, 2003.
Table 21 sets forth suitable process details for preparation of eucalyptus APMP for use in the present invention.







TABLE 21





Processing Conditions for eucalyptus APMP





















SAMPLE

A1
A2
A3
A4
A5


FURNISH

I1
A1
A1
A1
A1





kWh/ODMT APPLIED
PASS
584
87
181
301
322



Total
655
742
836
1137
1158


Total Alkalinity % Impregnation

1.1
1.1
1.1
1.1
1.1


Refiner

5.6
5.6
5.6
5.6
5.6


Total Applied

6.7
6.7
6.7
6.7
6.7


Residual

0.47
0.47
0.47
0.47
0.51


Net

6.23
6.23
6.23
6.23
6.19


Hydrogen Peroxide % Impregnation

1.1
1.1
1.1
1.1
1.1


Refiner

9.6
9.6
9.6
9.6
9.6


Total Applied

10.7
10.7
10.7
10.7
10.7


Residual

4.57
4.57
4.57
4.57
3.33


Net

6.13
6.13
6.13
6.13
7.37


FREENESS (CSF)

577
474
427
344
335


DENSITY

0.27
0.3
0.27
0.34
0.36


BULK (cm3/g)

3.69
3.28
3.68
2.92
2.81


BURST INDEX (kPa · m2/g)

0.59
0.84
1.07
1.47
1.44


TEAR INDEX (mN · m2/g)

3.7
4.5
4.7
4.8
4.9


TENSILE INDEX (N · m/g)

16
23.7
28.3
34.6
38


Breaking Length km

1.6
2.4
2.9
3.5
3.9


% STRETCH

0.86
1.13
1.33
1.52
1.65


TEA (J/m2)

4.81
9.33
13.38
19.04
22.92


ABSORPTION COEFF. (m

0.21
0.2
0.2
0.21
0.22


% OPACITY

80.7
81.1
82.5
82.9
83.5


SCATT. COEFF. (m2/kg)

47
48.2
52
52.8
54


ISO BRIGHTNESS

85.6
85.9
85.8
86
85.4


% SHIVES (PULMAC-0.10 mm)

12.34
6.98
4
0.78
0.68


LENGTH WEIGHTED AVG LNG (mm)

0.893
0.845
0.831
0.782
0.762


ARITHMETIC AVG. LENGTH (mm)

0.455
0.446
0.446
0.451
0.447


WGT WEIGHTED AVG LNG(mm)

1.87
1.57
1.54
1.22
1.12


AVERAGE WIDTH(pm)

32.7
31.91
31.23
29.46
29.15


SURFACE AREA (m2)

1155
1060
1305
1371
1592














FIBER
% ON 14 MESH

10.1
5.9
3.2
1.1
0.9


CLASS
% ON 28 MESH

15.1
14.4
11.5
5.3
4.7



% ON 48 MESH

26.4
29.8
31.3
34.7
33.4



% ON 100 MESH

20.8
20.8
22
25.4
24.2



% ON 200 MESH

14
13.8
14.4
16.6
15.9



% THRU 200 MESH

13.6
15.3
17.6
16.9
20.9



+28 MESH

25.2
20.3
14.7
6.4
5.6
















SAMPLE

A6
A7
A8
A9
A10


FURNISH

I1
A6
A6
A6
A6





kWh/ODMT APPLIED
PASS
576
78
140
187
226



Total
647
725
787
974
1013


Total Alkalinity % Impregnation

1.1
1.1
1.1
1.1
1.1


Refiner

10
10
10
10
10


Total Applied

11.1
11.1
11.1
11.1
11.1


Residual

2.01
2.01
2.01
2.01
2.94


Net

9.09
9.09
9.09
9.09
8.16


Hydrogen Peroxide % Impregnation

1.1
1.1
1.1
1.1
1.1


Refiner

11.9
11.9
11.9
11.9
11.9


Total Applied

13
13
13
13
13


Residual

0.92
0.92
0.92
0.92
0.74


Net

12.08
12.08
12.08
12.08
12.26


FREENESS (CSF)

541
448
396
317
307


DENSITY

0.36
0.38
0.41
0.46
0.47


BULK (cm3/g)

2.78
2.62
2.43
2.15
2.11


BURST INDEX (kPa · m2/g)

1.1
1.6
1.99
2.38
2.73


TEAR INDEX (mN · m2/g)

5.9
6.6
6.1
6.1
6


TENSILE INDEX (N · m/g)

28.7
36.7
42.2
52.6
55


Breaking Length km

2.9
3.7
4.3
5.4
5.6


% STRETCH

1.21
1.49
1.7
2.07
2.34


TEA (J/m2)

12.56
19.47
25.92
39.63
49.01


ABSORPTION COEFF. (m

0.28
0.27
0.23
0.25
0.25


% OPACITY

79.7
79.9
80.6
80.2
80.8


SCATT. COEFF. (m2/kg)

42.7
45.3
46.7
45.8
46.2


ISO BRIGHTNESS

84.9
85.4
85.2
84.8
84.7


% SHIVES (PULMAC-0.10 mm)

11.84
5.54
2.68
1.08
0.78


LENGTH WEIGHTED AVG LNG (mm)

0.806
0.813
0.84
0.784
0.772


ARITHMETIC AVG. LENGTH (mm)

0.455
0.448
0.447
0.453
0.452


WGT WEIGHTED AVG LNG(mm)

1.3
1.37
1.65
1.19
1.2


AVERAGE WIDTH(pm)


31.07
32.15
29.52
29.05


SURFACE AREA (m2)

1467
1277
1045
1629
1465














FIBER
% ON 14 MESH

9.2
4.7
3.1
0.8
0.6


CLASS
% ON 28 MESH

16
13
11.4
6.4
4.7



% ON 48 MESH

27.1
29.6
34
35.2
35.6



% ON 100 MESH

21.1
22
23.7
24.3
25



% ON 200 MESH

13.1
14.1
14.6
16.2
16.2



% THRU 200 MESH

13.5
16.6
13.2
17.1
17.9



+28 MESH

25.2
17.7
14.5
7.2
5.3









Example 5
This example is taken from U.S. Provisional Patent Application No. 61/574,200, entitled “High Softness, High Durability Bath Tissue Incorporating High Lignin Eucalyptus Fiber”, filed on Jul. 28, 2011, naming Jeffrey A. Lee and Daniel W. Sumnicht as inventors, illustrating the suitability of eucalyptus pre-conditioning refiner chemical alkaline peroxide mechanical pulp referred to herein as eucalyptus APMP for short. We have found that we can get surprisingly good softness, bulk and wet properties using eucalyptus APMP, in conjunction with relatively low contents of CMF, even in CWP products. Accordingly, it is evident that eucalyptus APMP can be substituted into the formulations described elsewhere in this application to significant benefit, particularly, in cases where the amount of CMF is below 20% by weight.
Experimental Procedure
Pulps were distributed from Tanks according to Table 22. The strategy for the outer plies was to make a Yankee layer with kraft pulp and good durability with a layer of high-bulk APMP or other integrated furnish. The middle ply was homogeneously formed with a high (65%) percentage of APMP to maximize bulk or 100% southern kraft. P6 high bulk APMP was used for outer plies, and P3 APMP was used for the middle ply. Marathon NBSK was unrefined. The source of eucalyptus was Votorantim Celulose e Papel (VCP), aka Fibria, Sao Paulo, Brazil.











TABLE 22








Tank 1, Air layer
Tank 3, Yankee layer
Total














Cell
B.W.
Pulp
B.W
Pulp
BW
Purpose







Stratified
















1
3.9
P6 APMP
7.1
50/50 Mar./Euc.
11
Outer plies


2
4.4
P6 APMP
8.2
50/50 Mar./Euc.
12.6
Outer plies


3
4.5
P6 APMP
6.5
18/41/41 CMF/Mar./Euc.
11
Outer plies


7
3.9
40/60 P3 APMP/Fibria
7.1
15/42/43 CMF/Mar./Euc.
11
Outer plies


8
5.5
50/50SSWK/SHWK
7.1
15/42/43 CMF/Mar./Euc.
12.6
Outer plies


9
6.2
50/50 SSWK/SHWK
6.2
20% CMF/80% Euc. Kraft
12.4
Outer plies










Homogeneous












Cell
B.W.
Pulp
Purpose






 4
12.6
65/35 P3 APMP/Mar.
Middle ply



 5
11
65/35 P3 APMP/Mar.
Middle ply



 6
12.6
50/50 SSWK/SHWK
Middle ply



10

50/50 SSWK/SHWK
Middle ply, No FJ 98





Mar. = Marathon NBSK






Nalkat® 2020 was added as an “anionic trash killer” at 5 lb/ton APMP. This was done to prevent trash from poorly washed pilot APMP from interfering with retention of temporary wet strength. GP-C, an imidazolinum type softener, was added to the static mixer at 3 lb/ton APMP. T1 and T3 pH were adjusted to 5.0 to 5.5 with sulfuric acid to optimize retention of temporary wet strength. FJ98 (low molecular weight slightly cationic glyoxalated polyacrylamide temporary wet strength agent) was added into the pump suction at 6 lb/ton kraft pulp. GP-C was added at 3 lb/ton Yankee layer just before the fan pump.
All sheets for outer plies were calendered and had a geometric mean tensile (GMT) target of 350 g/3 in. and cross machine direction wet tensile (CDWT) target of 40 g/3 in. Sheets for middle plies were uncalendered and creped with a 10 degree bevel blade. Tensile control was achieved by increasing FJ98 or increasing debonder as necessary. A reel crepe of 25% was used for all basesheets. A 15° crepe blade was used for outer plies. In some cases, use of creping adhesive could be dispensed with, so water alone could be applied through the Yankee spray, as sufficient adhesion for satisfactory creping was provided by FJ98 and the hemicellulose remaining in the eucalyptus APMP. In other cases, when debonder in the sheet interfered with adhesion, it was desirable to apply about 0.25 to 0.5 lb/ton PAE coating to the Yankee. A sheet temperature of 230° F. was targeted. Only Yankee steam (no hood) was necessary for drying.
Method of Analysis
Results set forth in Table 23 were obtained when converted into finished product and evaluated for basis weight, caliper, wet and dry tensiles, softness, wet and dry lint and dispersibility. FIG. 14 sets forth a desirable design for a three-ply bath tissue 4-10 product utilizing eucalyptus APMP, in which upper ply 4-12 comprising two strata 4-14 and 4-16, in which upper stratum 4-14 comprising 50% northern bleached softwood kraft fiber and 50% by weight of eucalyptus kraft has a basis weight of about 7.1 lbs per 3000 sq ft ream; lower stratum 4-16 comprising 100% P6 eucalyptus APMP has basis weight of 3.9 lbs per 300 sq ft ream; while interior ply 4-18 comprising 65% P3 APMP and 35% by weight of northern bleached softwood kraft has a basis weight of 11 lbs/ream while lower ply 4-20 comprising two strata 4-22 and 4-24, in which lower stratum 4-24 comprising 50% northern bleached softwood kraft fiber and 50% by weight of eucalyptus kraft has a basis weight of about 7.1 lbs per 3000 sq ft ream; and upper stratum 4-22 comprising 100% P6 eucalyptus APMP has a basis weight of 3.9 lbs per 300 sq ft ream. It can be observed that upper ply 4-12 and interior ply 4-18 have been embossed together while lower ply 4-20 is relatively planar and is preferably unembossed. While the configuration shown in FIG. 14 is somewhat more convenient for manufacturing, in many instances, lower ply 4-20 will be inverted so that stratum 4-22 is on an exterior surface of the sheet to take advantage of its usually superior tactile properties.
Table 23 summarizes the properties of CWP prototypes wherein the three-ply prototypes therein are made having a structure like that illustrated in FIG. 14. Where “knurl” is indicated in the converting column, interior ply 4-18 was joined to lower ply 4-20 by knurling in a meandering path. Where “glue” is indicated in the converting column, the plies were joined to each other by glue lamination. Note that the last two rows provide a comparison to Quilted Northern® Ultra Plush bath tissue and prototypes made using a newer technology, in which a nascent web is creped off of a transfer cylinder at between 30% and 60% consistency. Table 24 sets forth details concerning the structure of each glue laminated product; while Tables 24A-24G set forth further details on the physical properties of the finished products and basesheets, the finished product composition, and the converting parameters used for of each of the finished glue laminated products. Tables 25A-25D do the same for the knurled products. Tables 26 to 28 delineate the properties and construction of CWP sheets made using a high bulk birch pulp manufactured by a high yield pulping process.







TABLE 23







Summary of CWP prototypes.



















Basis



CD








weight,



Wet,
Dry
Wet
Dispers-





lb/3000
Caliper,
GMT,

g/3
Lint,
lint,
ibility,



Item
Description
ft2
mil/8 sht
g/3 in.
Softness
in.
ΔL*
mm2
#shakes
Converting




















 1
High-bulk mechanical HW
27.0
131
888
19.7
193
0.4


2-ply, HVS9 knurl



w/CMF











 2
High-bulk mechanical HW
37.7
174
899
20.0
192
−0.1


2-ply, HVS9 knurl



w/CMF











 3
High durable no cmf
27.0
101
2405
17.5
342
0.2
1

3-ply, U19 lines, glue


 4
Med durable no cmf
28.1
95
2076
18.1
267
0.9
7

3-ply, U19 lines, glue


 5
Less durable no cmf
28.4
105
1495
18.5
193
1.9
12

3-ply, U19 lines, glue


 6
Less durable 20% cmf
26.7
95
2034
17.8
229
0.8
3

3-ply, U19 lines, glue


 7
High durable 20% cmf
27.2
96
2633
17.2
382
0.2
1

3-ply, U19 lines, glue


 8
Euc APMP 33%
38.5
145
902
19.1
85
6.0
19

3-ply, U19 lines, glue


 9
Euc APMP 50%
30.5
112
731
18.9
59
5.6
28

2-ply, U19 lines, glue


10
Euc APMP 60%
38.8
145
850
18.2
60
5.9
24

2-ply, U19 lines, glue


11
Euc APMP 44%
{circumflex over ( )}
152
982
19.3
90
2.1
11
688
3-ply, U19, glue


12
Euc APMP 44%
36.3
160
1018
19.4
116
4.3
15
1450
3-ply, U19, glue


13
Euc APMP 49%, 7% CMF
32.7
148
835
19.3
92
2.6
4
575
3-ply, U19, glue


14
Euc APMP 49%, 7% CMF
32.5
146
1035
19.1
130
0.6
2
838
3-ply, U19, glue


15
Euc APMP 31%, 6% CMF
32.4
139
1005
19.1
108
1.7
6
975
3-ply, U19, glue


16
Southern 62%, 6% CMF
36.7
147
1165
19.3
101
1.5
6
2000
3-ply, U19, glue


17
Integrated 57%
34.3
154
737
20.0
72
2.4
66
875
3-ply, HVS9 knurl


18
Integrated 57%
35.1
160
619
20.4
73
5.0
22
1000
3-ply, HVS9 knurl


19
Euc APMP 49%, 7% CMF
31.0
146
765
19.8
100
1.1
18
850
3-ply, HVS9 knurl


20
Euc APMP 49%, 7% CMF
32.1
148
953
19.8
126
0.7
3
1450
3-ply, HVS9 knurl


21
Euc APMP 33%, 6% CMF
32.7
143
888
19.6
100
2.0
10
1025
3-ply, HVS9 knurl


22
Southern 63%, 6% CMF
36.7
148
954
19.8
99
1.9
8
2000
3-ply, HVS9 knurl


23
Southern 65%, 7% Pilot CMF
35.8
150
788
20.1
68
3.8
13
2000
3-ply, HVS9 knurl


24
Southern 65%, 7% Pilot CMF
35.0
150
823
20.1
89
2.7
11
2000
3-ply, HVS9 knurl







Comparatives
















FRBC P3403G
26.3
145
932
19.3
113
5.4
30
600



Quilted Northern ® UltraPlush
37.0
148
773
20.0
40



3-ply, HVS9 knurl
















TABLE 24







Basesheet data for Three-Ply U19/glue lamination prototypes
































Wet








Base-







Tens








sheet
Caliper
Basis





Finch
Break
Break
Break


11.2011-


De-
8 Sheet
Weight
Tensile
Stretch
Tensile
Stretch
Tensile
Cured-
Modulus
Modulus
Modulus


0039
Conv.
PM
scrip-
mils/8
lb/3000
MD
MD
CD
CD
GM
CD
GM
CD
MD


Sample
Cell
cell
tion
sht
ft.2
g/3 in.
%
g/3 in.
%
g/3 in.
g/3 in.
gms/%
gms/%
gms/%
























 4-1
1
1
0110-4 
49.1
11.4
386
28.5
284
4.7
331
23
29
60
14


32-1
1
5
0110-31
64.6
11.5
476
31.1
260
4.3
351
54
29
55
16


 5-1
1
1
0110-5 
47.3
11.4
351
26.9
277
4.4
311
27
28
65
12






160.9
34.3
1214
28.8
 821′
4.45
993
104
29
60
14


10-1
2
2
0110-9 
50.1
12.5
410
29.6
327
4.4
365
42
32
72
14


27-1
2
4
0110-26
65.9
117
629
29.7
372
4.2
482
62
49
108
22


11-1
2
2
0110-10
53.2
12.6
331
28.7
253
4.7
289
35
25
54
12






169.2
37.8
1369
29.3
952
4.45
1136
139
35
78
16


15-1
3
 3A
0110-14
46.1
11.2
483
32.2
316
5.1
391
44
32
69
15


31-1
3
5
0110-30
62.2
11.6
552
30.2
312
3.9
415
48
38
80
18


16-1
3
 3A
0110-15
48.5
110
381
30.9
264
4.7
317
34
27
60
12






156.8
33.8
1416
31.1
893
4.54
1123
127
32
70
15


19-1
4
  3B
0110-18
45.8
10.9
472
29.8
365
4.9
415
66
34
74
16


26-1
4
4
0110-25
65.4
13.1
757
29.3
435
3.8
574
74
56
120
26


20-1
4
  3B
0110-19
46.0
10.9
491
30.8
356
5.0
417
63
33
73
15






157.2
34.9
1719
29.9
1157 
4.59
1406
202
41
89
19


39-1
5
7
0110-38
43.7
11.7
462
29.8
313
5.8
380
47
28
50
15


30-1
5
5
0110-29
62.0
11.4
604
28.1
330
4.1
443
33
41
72
23


40-1
5
7
0110-39
41.1
10.8
383
29.3
285
5.1
330
42
27
56
13






146.8
33.9
1449
29.1
928
4.99
1154
123
32
59
17


46-1
6
8
0110-45
45.0
12.5
539
28.9
318
5.6
413
39
32
57
18


35-1
6
6
0110-34
63.0
12.8
322
35.9
268
5.5
293
31
21
47
9


47-1
6
8
0110-46
44.8
12.9
575
28.7
355
5.7
452
42
35
61
20






152.8
38.2
1436
31.1
941
5.58
1157
112
29
55
15
















TABLE 24A







Ply data for low-weight CWP products. Basesheet data for each Ply




















X-Ref


8 Sheet
Basis





CD Wet
GM



to


Caliper
Weight
MD
MD
CD
CD
GM
Tensile
Break



Table
Roll

Mils/8
Lb/3000
Tensile
Stretch
Tensile
Stretch
Tensile
Cured
Modulus


Cell
23
ID

sht
ft2
g/3 in.
%
g/3 in.
%
g/3 in.
g/3 in.
gms/%






















1
3
1130-4 
Hi durable
27.0
9.2
1259
31.3
870
4.7
1045
171
87




1130-5 
No CMF
27.3
9.2
1112
31.9
712
4.4
888
149
75




1130-6 

27.8
8.8
1330
33.2
859
4.4
1067
127
87


2
4
1130-7 
Med durable
29.5
9.6
1092
33.0
562
4.0
782
90
67




1130-8 
No CMF
29.1
9.7
990
32.4
665
4.6
811
92
71




1130-9 

27.0
8.9
1091
34.8
575
4.7
791
99
61


3
5
1130-16
Less
31.7
9.1
461
31.1
380
5.2
418
49
32




1130-17
durable
32.7
9.9
632
34.3
494
5.2
559
64
43




1130-18
No CMF
30.8
9.2
572
31.6
392
4.9
471
64
38


4
6
1130-20
Less
30.1
9.2
972
33.3
509
6.1
703
70
47




1130-21
durable
30.8
9.5
1029
33.5
506
6.6
721
71
45




1130-22
20% CMF
29.5
9.1
852
33.1
501
6.4
653
58
48


5
7
1130-24
Hi durable
29.6
9.6
1201
34.9
705
5.6
920
118
72




1130-25
20% CMF
28.5
9.3
1198
32.3
625
6.4
865
115
58




1130-26

26.1
8.4
889
30.3
550
6.1
699
126
51


6
8
4905-57
High bulk
52.1
13.1
379
27.6
301
5.1
337
36
29




4905-58
33% APMP
48.5
12.6
409
25.9
298
4.8
348
31
32




4905-59

49.2
12.9
391
27.7
306
5.7
345
31
27


7
9
4905-60
High bulk
61.4
16.1
460
28.5
381
5.3
417
36
35




4905-61
50%APMP
61.5
15.9
492
28.0
339
5.1
408
39
33


8
10
4905-62
High bulk
81.7
20.3
508
26.6
434
5.0
469
38
41




4905-63
60% APMP
80.1
20.6
633
28.0
459
5.3
539
40
45
















TABLE 24B







Finished product composition.














Euc APMP
SBHK
SBSK
NBSK
Euc Kraft
CMF
















1
44.4
0.0
0.0
33.7
21.9
0.0


2
44.4
0.0
0.0
33.7
21.9
0.0


3
48.6
0.0
0.0
28.1
16.1
7.2


4
49.4
0.0
0.0
28.4
15.3
6.9


5
31.3
0.0
0.0
29.8
32.6
6.4


6A
0.0
31.2
31.2
15.8
16.1
5.6


6B
0.0
31.2
31.2
15.8
16.1
5.6
















TABLE 24C





Converting Parameters (U19/Glue)


















Emboss Sleeves: U19 300-0436.2 HVS
Sheet Length: 4.09



Plybond Adhesive: TT 3005, 5% solids
Sheet Count: 200



Perf Blades: 1866 X 0.040




















Middle
Back
Marry
# of



Cell
Emboss
Front
Roll #
Roll #
Roll Nip
logs/



ID
Pen.
Roll #
Embossed
Embossed
Open/Closed
Rolls
Notes





1
0.052
Cell 1-4
Cell 5-31
Cell 1-5
16 mm
12/24



2
0.052
Cell 2-9
Cell 4-26
Cell 2-10
16 mm
 6/12



3
0.055
Cell 3A-14
Cell 5-30
Cell 3A-15
16 mm
13/26



4
0.055
Cell 3B-18
Cell 4-25
Cell 3B-19

16/32
Decreased marry









roll nip width


5
0.052
Cell 7-38
Cell 5-29
Cell 7-39

16/32



6A
0.052
Cell 8-45
Cell 6-34
Cell 8 - 46

 6/12



6B
0.045
Cell 8-45
Cell 6-34
Cell 8 - 46

10/20
















TABLE 24D







Glue Laminated Finish Product - Physical Properties (pt. 1)

























Lint
Basis
Caliper





CD Wet



Table


Wet
Black
Weight
8 Sheet
MD
CD
GM
MD
CD
Tens



23

Softness
Abrasion
Felt
lb/3000
mils/8
Tensile
Tensile
Tensile
Stretch
Stretch
Finch



ref
Description
Panel
mm2
Unitless
ft2
sht
g/3 in.
g/3 in.
g/3 in.
%
%
g/3 in.























1
3
High durable no cmf
17.5
1
0.2
27.0
101
3,242
1,709
2,405
28.0
5.1
342


2
4
med durable no cmf
18.1
7
0.9
28.1
95
2,688
1,604
2,076
27.7
5.6
267


3
5
less durable no cmf
18.5
12
1.9
28.4
105
1,888
1,185
1,495
26.1
5.2
193


4
6
less durable 20& cmf
17.8
3
0.8
26.7
95
2,899
1,428
2,034
28.1
6.3
229


5
7
High durable 20% cmf
17.2
1
0.2
27.2
96
3,727
1,862
2,633
28.9
6.2
382


6
8
33% APMP (P6)
19.1
19
6.0
38.5
145
1,105
738
902
19.8
4.7
85


7
9
5-% APMP (P6)
18.9
28
5.6
30.5
112
878
610
731
20.5
5.2
59


8
10
60% APMP (P6)
18.2
24
5.9
38.8
145
1,040
698
850
19.0
4.7
60




























TABLE 24E








GM
Brtness


Roll
TMI
MD
CD
MD
CD



Table

Break
MacBeth
MacBeth
Roll
Compress
Ply
Break
Break
TEA
TEA



23

Modulus
UV-C
Opacity
Diameter
Value
Bond
Modulus
Modulus
mm-g/
mm-g/



ref
Description
g/%
%
Units
in
%
g
g/%
g/%
mm2
mm2



























1
3
High durable no cmf
203
89.7
72
4.80
29.29
4.65
116
355
4.20
0.59


2
4
med durable no cmf
166
89.8
72
4.32
19.10
5.14
96
287
3.66
0.59


3
5
less durable no cmf
129
89.8
73
4.55
19.33
20.69
73
230
2.61
0.40


4
6
less durable 20& cmf
151
91.6
80
4.26
17.84
8.63
104
220
3.44
0.60


5
7
High durable 20% cmf
196
91.3
79
4.38
17.93
3.98
128
300
4.27
0.80


6
8
33% APMP (P6)
92
87.8
82
4.91
21.40
9.54
56
153
1.46
0.23


7
9
5-% APMP (P6)
71
87.8
77
4.12
13.73
11.80
43
118
1.24
0.22


8
10
60% APMP (P6)
89
86.6
83
4.71
16.88
10.96
55
145
1.37
0.23
















TABLE 24F







Finished product composition for CWP sheets












NBSK
VCP Eucalyptus Kraft
Euc APMP P6
CMF















1
40
40
0
20


2
40
40
0
20


3
40
40
0
20


4
40
40
0
20


5
40
40
0
20


6
40
27
33
0


7
30
20
50
0


8
24
16
60
0
















TABLE 24G







Glue Laminated Finished product - Physical Properties (pt. 1)























Wet
Lint
Basis
Caliper








Table

Dispers-
Abrasion
Black
Weight
8 Sheet
Tensile
Tensile
Tensile
Stretch
Stretch


Descrip-
23
Softness
ibility,
Tissue
Felt
lb/3000
mils/8
MD
CD
GM
MD
CD


tion
ref
Panel
#shakes
mm2
Unitless
ft2
sht
g/3 in.
g/3 in.
g/3 in.
%
%





1
11
19.33
688
11.0
2.1
33.7
152
1,280
756
982
22.2
5.1


2
12
19.35
1450
15.1
4.3
36.3
160
1,169
886
1,018
21.7
4.9


3
13
19.31
575
3.9
2.6
32.7
148
1,019
688
835
20.3
5.2


4
14
19.05
838
1.7
0.6
32.5
146
1,314
818
1,035
20.6
5.3


5
15
19.11
975
6.3
1.7
32.4
139
1,315
769
1,005
22.2
5.1


6A
16
19.29
2000
5.9
1.5
36.7
147
1,468
926
1,165
25.5
5.9


6B
—
19.31
2000
5.4
1.3
36.8
143
1,464
971
1,190
26.6
5.8










Glue Laminated Finished product - Physical Properties (pt. 2)



















Table
Perf
Finch
Modulus
Roll

TMI
Modulus
Modulus




Descrip-
23
Tensile
CD
GM
Diameter
Compress
Ply
MD
CD
mm-gm/
mm-gm/


tion
ref
g/3 in.
g/3 in.
gms/%
in
Value %
Bond g
gms/%
gms/%
mm{circumflex over ( )}2
mm{circumflex over ( )}2





1
11
377
90
94
5.06
21.9
9.0
58
153
1.65
0.28


2
12
412
116
100
5.13
21.2
7.5
55
182
1.60
0.32


3
13
336
92
81
5.13
26.5
8.8
50
130
1.27
0.25


4
14
448
130
100
4.95
22.6
8.0
64
156
1.55
0.31


5
15
397
108
94
4.98
27.8
11.1
60
150
1.62
0.29


6A
16
441
101
95
4.91
22.5
15.3
57
158
1.96
0.40


6B
—
421
106
97
5.04
28.4
14.6
56
168
2.04
0.42
















TABLE 25A







Construction data for HVS9/knurl prototypes w/Basesheet data.























8 Sheet
Basis





CD Wet
GM


TL2011-



Caliper
Weight
MD
MD
Tensile
Stretch
Tensile
Tens Finch
Break


0039
Converting
PM
Descrip-
mils/8
lb/3000
Tensile
Stretch
CD
CD
GM
Cured
Modulus


Sample
Cell
cell
tion
sht
ft2
g/3 in.
%
g/3 in.
%
g/3 in.
g/3 in.
g/%






















 6-1
1
1
0110-6 
46.9
11.1
365
28.8
280
4.5
320
26
29


37-1
1
6
0110-36
57.7
12.1
407
35.0
361
5.3
383
49
29


 7-1
1
1
0110-7 
47.4
11.3
369
28.7
294
4.6
329
27
29






152.0
34.5
1141
30.8
935
4.8
1031
102
29


12-1
2
2
0110-11
56.0
12.7
335
29.9
290
4.5
311
33
26


34-1
2
6
0110-33
63.5
13.0
357
38.7
274
5.4
312
30
23


13-1
2
2
0110-12
52.2
12.3
326
29.1
250
5.3
285
34
22






171.7
37.9
1018
32.6
815
5.1
908
96
24


17-1
3
 3A
0110-16
46.9
10.9
417
30.3
341
5.0
376
49
31


29-1
3
5
0110-28
62.8
11.8
453
30.4
363
4.4
405
45
35


18-1
3
 3A
0110-17
45.8
10.5
382
29.3
301
5.2
338
43
27






155.4
33.2
1252
30.0
1005
4.9
1119
137
31


21-1
4
  3B
0110-20
45.8
11.0
475
31.3
344
5.0
404
59
32


25-1
4
4
0110-24
63.8
12.3
708
30.0
374
4.1
514
47
46


22-1
4
  3B
0110-21
45.8
10.5
393
29.9
311
6.2
350
59
24






155.3
33.7
1576
30.4
1029
5.1
1268
165
34


41-1
5
7
0110-40
41.6
10.8
365
27.9
274
5.2
316
42
27


28-1
5
4
0110-27
65.8
13.0
734
29.3
419
4.2
554
72
49


42-1
5
7
0110-41
41.2
10.8
363
30.4
284
5.3
321
39
25






148.6
34.6
1462
29.2
977
4.9
1191
153
34






162.9

1097

733

893
115



48-1
6
8
0110-47
46.1
12.7
606
31.3
357
5.2
465
45
37


36-1
6
6
0110-35
63.7
13.6
390
35.3
312
5.0
345
43
27


49-1
6
8
0110-48
45.7
12.5
484
28.1
293
5.6
376
38
31






155.4
38.8
1480
31.6
962
5.3
1186
126
32






170.4

1110

721

890
94



56-1
7
9
0216-7 
46.3
12.6
404
30.9
336
5.3
368
35
29


66-1
7
10 
0216-16
66.6
12.7
323
36.9
238
5.8
277
6
19


57-1
7
9
0216-8 
47.6
12.5
477
32.7
362
5.2
415
35
31






160.5
37.9
1203
33.5
936
5.4
1060
75
26


58-1
8
9
0216-9 
46.0
12.5
442
30.5
331
4.9
382
39
32


63-1
8
6
0216-13
64.8
12.5
390
35.8
332
5.8
359
45
24


59-1
8
9
0216-10
46.8
12.7
451
31.0
369
5.0
408
39
34






157.6
37.7
1284
32.4
1032
5.2
1149
124
30
















TABLE 25B







Finished product composition for HVS 9 Knurl Products.














APMP Euc.
SBHK
SBSK
NBSK
Kraft Euc.
CMF
















1
22
17
17
21
21
0


2
22
17
17
22
22
0


3
49
0
0
28
16
7.1


4
49
0
0
28
16
7.0


5
33
0
0
30
31
6.0


6
0
32
32
15
16
5.5


7
0
32
32
0
28
7.0


8
0
32
32
0
28
7.1
















TABLE 25C







HVS9/knurl finished product Physical Properties (pt. 1)





















Dispers-
Wet
Lint
Basis
Caliper







Table

ibility
Abrasion
Black
Weight
8 Sheet
Tensile
Tensile
Stretch
Stretch


Descrip-
23
Softness
# of
Tissue
felt
lb/3000
mils/8
MD
GM
MD
CD


tion
desc.
Panel
Shakes
mm2
Unitless
ft2
Sheet
g/3 in.
g/3 in.
g/3 in.
%





5-1
17
20.02
875

2.4
34.3
154
910
599
18.1
4.8


5-2
18
20.36
1000

5.0
35.1
160
762
505
17.8
5.1


5-3
19
19.84
850

1.1
31.0
146
1,008
583
17.4
5.2


5-4
20
19.79
1450

0.7
32.1
148
1,230
740
18.4
5.0


5-5
21
19.56
1025

2.0
32.7
143
1,225
645
18.7
5.0


5-6
22
19.79
2000

1.9
36.7
148
1,292
705
21.5
5.6


5-7
23
20.10
2000

3.8
35.8
150
918
679
20.3
5.1


5-8
24
20.08
2000

2.7
35.0
150
946
718
18.9
5.0










HVS9/knurl finished product Physical Properties (pt. 2)





















Wet













Tens
Break

Roll
TMI
Break
Break
TEA
TEA



Table
Perf-
Finch
Modulus
Roll
Compress
Ply
Modulus
Modulus
MD
CD


Descrip-
23
Tensile
CD
GM
Diameter
Value
Bond
MD
CD
mm-g/
mm-g/


tion
desc.
g/3 in.
g/3 in.
g/%
in
%
g
g/%
g/%
mm2
mm2





5-1
17
389
72
80
4.96
21
7.9
51.7
124.6
1.02
0.19


5-2
18
354
73
64
4.83
23
5.7
43.1
94.3
0.86
0.17


5-3
19
343
100
80
5.00
24
3.2
57.3
112.1
1.03
0.20


5-4
20
456
126
100
5.04
23
4.4
67.4
148.0
1.31
0.24


5-5
21
431
100
93
4.92
22
6.8
66.5
130.1
1.28
0.21


5-6
22
518
99
87
5.03
24
8.7
60.5
125.3
1.51
0.26


5-7
23
358
68
78
4.91
20
6.9
45.6
132.4
1.13
0.22


5-8
24
352
89
85
5.07
25
7.7
49.9
146.4
1.07
0.23
















TABLE 25D







Converting parameters


Sheet Length 4.09′′


Sheet Width 4.05′′
























#1
#2
#3





Un-
Un-
Un-
Ply-



Fin-



Un-
Un-
Un-
Lower


Feed-

wind
wind
wind
bond

Wind-

ished



wind
wind
wind
Emboss
Con-
Lower
roll
Mach.
Ten-
Ten-
Ten-
Air
Draw
ing

Roll


Cell
Base
Base
Base
Pat-
verting
Emboss
Cal-
Speed
sion
sion
sion
Pres-
Ten-
Ten-
Sheet
Diam-


No.
Sheet
Sheet
Sheet
tern #
Process
Depth
ender
FPM
#1
#2
#3
sure
sion
sion
Count
eter





1
110-6
110-36
110-7
300-107.1
3 ply
0.090
open
130
0.5
0.5
0.5
23
float
0.8
200
4.92







HVS






psi






2
 110-12
110-33
 110-11
300-107.1
3 ply
0.090
open
130
0.5
0.5
0.5
23
float
0.6
176
4.84







HVS






psi






8
 216-10
216-13
216-9
300-107.1
3 ply
0.090
open
130
0.5
0.5
0.5
23
float
0.5
200
4.94







HVS






psi






6
 110-48
110-35
 110-47
300-107.1
3 ply
0.090
open
130
0.5
0.5
0.5
23
float
0.7
200
4.90







HVS






psi






3
0110-17
0110-28 
0110-16
300-107.1
3 ply
0.090
open
130
0.5
0.5
0.5
23
float
0.8
200
4.89







HVS






psi






4
0110-21
0110-24 
0110-30
300-107.1
3 ply
0.090
open
130
0.5
0.5
0.5
23
float
0.9
200
4.95







HVS






psi






5
0110-41
0110-27 
0110-40
300-107.1
3 ply
0.090
open
130
0.5
0.5
0.5
23
float
0.8
200
4.89







HVS






psi






7
216-8
216-16
216-7
300-107.1
3 ply
0.090
open
130
0.5
0.5
0.5
23
float
0.7
200
4.92







HVS






psi
















TABLE 26







Physical Properties of two-ply, high-bulk tissue with Tembec birch APMP (pt. 1).























CD Wet



8 Sheet
Basis





Tens



Caliper
Weight
MD
MD
CD
CD
GM
Finch


Descrip-
mils/8
lb/3000
Tensile
Stretch
Tensile
Stretch
Tensile
Cured


tion
sht
ft2
g/3 in.
%
g/3 in.
%
g/3 in.
g/3 in.





0302-2
62
14.1
879
28.1
595
5.1
723
172


0302-3
64
14.5
988
30.3
546
5.4
734
163


0302-4
88
19.9
868
28.1
587
5.0
714
154


0302-5
84
19.7
884
28.4
701
5.0
786
183










Physical Properties of two-ply, high-bulk tissue with Tembec birch APMP (pt. 2).
















GM



CD
MD
CD
MD



Break
SAT
SAT
SAT
T.E.A
TEA
Break
Break


Descrip-
Modulus
Capacity
Rate
Time
mm-gm/
mm-gm/
Modulus
Modulus


tion
gms/%
g/m2
g/s0.5
s
mm2
mm2
gms/%
gms/%





0302-2
61
337
0.0613
124.9
0.21
0.96
117
32


0302-3
58
350
0.0667
112.6
0.21
1.12
102
33


0302-4
58
548
0.1047
141.4
0.20
1.01
109
31


0302-5
63
532
0.1043
146.6
0.25
1.03
137
29
















TABLE 27







Overall Composition of 3 Ply prototypes* using Tembec Birch APMP


for bulky inner layer.












Mar. NBSK
VCP Euc
CMF
Birch APMP















1
32%
7%
10%
51%


2
23%
5%
7%
65%
















TABLE 28







Physical Properties of 3 Ply prototypes* using Tembec Birch APMP for bulky inner layer (pt. 1).



























Wet




Lint
Basis
Caliper





Tens




Black
Weight
8 Sheet
Tensile
Tensile
Tensile
Stretch
Stretch
Finch


Descrip-
Softness
Felt
lb/3000
mils/8
MD
CD
GM
MD
CD
CD g/3


tion
Panel
Unitless
ft2
sht
g/3 in.
g/3 in.
g/3 in.
%
%
in.





1
19.7
0.4
27.0
131
1,141
696
888
17.0
5.1
193


2
20.0
−0.1
37.7
174
1,143
713
899
18.7
4.7
192










Physical Properties of 3 Ply prototypes using Tembec Birch APMP for bulky inner layer (pt. 2).


















Break
Brtness
Opacity

Roll
TMI
Break
Break
TEA
TEA



Modulus
MacBeth
MacBeth
Roll
Compress
Ply
Modulus
Modulus
MD
CD


Descrip-
GM
UV-C
Opacity
Diameter
Value
Bond
MD
CD
mm-gm/
mm-gm/


tion
gms/%
%
Units
in
%
g
gms/%
gms/%
mm2
mm2





1
95.0
85.9
78.5
4.6
22.3
0.5
64.3
141.0
1.0
0.2


2
97.3
84.9
84.2
5.2
22.8
0.6
62.0
154.4
1.1
0.2





*Items 1 and 2 from Table 23






SUMMARY OF RESULTS
Table 23 illustrates several rather surprising results in that three-ply bath tissue incorporating eucalyptus APMP exceeded Quilted Northern® Ultra Plush caliper without unduly degrading softness. This is considered quite surprising for a bath tissue comprising such large quantities of high yield pulp.
Even with products with excellent resistance to pilling, linting and shredding, it was possible to achieve softness panel ratings greater than nineteen while reducing wet lint up to 96% versus Charmin® Ultra Strong. It can also be observed that in those products comprising rather small amounts of CMF, even further reductions in wet lint values were obtained. This was especially true of sheets containing CMF at 6 to 7% of furnish, wherein the CMF was concentrated in the surface strata of the outer plies by stratification without CMF in the inner ply. This is considered to be especially significant as, currently, CMF is substantially more expensive than most papermaking fibers. Accordingly, it is particularly important both to reduce the amount needed and to obtain easily perceptible benefit for the CMF. Products without CMF, however, particularly, those made with glue lamination, exhibited reduced wet lint relative to products where the plies were joined by knurling, thus making it possible to achieve excellent results without the use of CMF.
It is clear that applicants have succeeded in manufacturing a bath tissue that is usable prewetted, yet fully achieves a softness that is not merely comparable to premium and super premium bath tissue, but is at full parity and is arguably even softer, although the improvement is most likely not significant enough to be noticed reliably by most users. This is a dramatic reversal of previous wet strength bath tissues, in which it was hoped that the deficit in softness was not large enough to be readily noticeable by most users. The softness panel rating of 20.1 achieved with furnish comprising 7% pilot CMF, 65% southern softwood kraft, and 28% eucalyptus kraft is considered to be a significant improvement in wet strength bath tissue.
High basis-weight CWP prototypes comprising less than 30% southern pine with large amounts of eucalyptus APMP were dispersible, passing the test described above in under 1500 shakes. Surprisingly, high basis-weight CWP product with an excess of 30% southern pine did not pass the dispersibility test after 2000 shakes as, despite appearing to be disintegrated, the slurry did not drain with the requisite speed. It appears that dispersibility may be helped significantly by the inclusion of short, eucalyptus APMP fibers relative to longer southern pine kraft fibers.
Between comparable prototypes, products having plies joined by knurling had a slight edge in softness over glue laminated prototypes.
As expected, however, CWP products were at a disadvantage to those products produced by creping a nascent web at a 30 to 60% consistency off of a transfer cylinder.
Two-ply bath tissue made with a furnish including Tembec Birch APMP achieved a softness rating of 20 at 176 mil/8 sheet caliper, exhibiting considerable dusting along with knurled ply bonding, which was poor, suggesting that mechanical hardwood APMP other than eucalyptus may achieve a similar bulk result as eucalyptus if used in the interior ply of a three-ply product, but likely might be rather weak for use in the exterior plies.
These results, however, also demonstrate that the current best practice for making soft tissue does not optimize the properties of tissues to be used wet. In particular, the current best practice for dry tissue uses about 1⁄3 northern softwood kraft and 2⁄3 eucalyptus kraft with the softwood providing network integrity while the eucalyptus provides smoothness and opacity. When a stratified headbox is available, in a refinement of this approach, the eucalyptus is stratified in the Yankee side of the sheet and spray softeners are applied up to about the limit at which they begin to interfere with creping. The stronger air layer with softwood provides strength while the eucalyptus layer becomes very smooth and velvety. As mentioned, however, not only can spray softeners act as release agents interfering with effective creping of the sheet, and thus interfering with realization of the full softness potential of the sheet, but surfaces comprised of 100% eucalyptus kraft often have increased tendency to shed lint. Thus, it can be appreciated that a premium softness wet or dry bath tissue product does not necessarily result from merely adding temporary wet strength agents to traditional premium bath tissue products intended for dry use.
A different strategy is needed for wet-durable tissue to reduce the linting tendency for both dry and wet use. CMF and northern softwood are incorporated in the Yankee layer, while a temporary wet strength agent is concentrated in the Yankee layer to provide durability. Thus, the Yankee layer provides wet tensile and surface strength to reduce pilling. The air layer contains an integrated furnish that is debonded as much as is tolerable, with little or no temporary wet strength, as shown in the representative tissue structure of FIG. 14. In this approach to providing a premium softness wet or dry bath tissue, the outer plies are stratified with softness and integrity, providing premium fibers in the Yankee layer and lower cost furnish in the air layer to provide bulk and overall strength. The middle ply is homogeneously formed APMP and softwood kraft. Alternatively, the middle ply can be made with integrated furnish such as southern kraft. The middle ply is creped with a relatively closed pocket to create bulk through coarser crepe and uncalendered to preserve the bulk added by the coarse creping. In this approach, stratification to provide a strong coherent Yankee layer of low weight with a debonded air layer combined to produce a finely creped, but coherent tissue on the surface. FIG. 14 sets forth a desirable design for a three-ply bath tissue 4-10 product utilizing eucalyptus APMP, in which upper ply 4-12 comprising two strata 4-14 and 4-16, in which upper stratum 4-14 comprising primarily northern bleached softwood kraft fiber and eucalyptus kraft, has a basis weight of about 4 to 9 lbs per 3000 sq ft ream; lower stratum 4-16 comprising primarily eucalyptus APMP has basis weight of 2 to 6 lbs per 3000 sq ft ream; while interior ply 4-18 comprising primarily APMP and northern bleached softwood kraft has a basis weight of 7 to 15 lbs/ream, while lower ply 4-20 comprising two strata 4-22 and 4-24, in which lower stratum 4-24 comprising primarily northern bleached softwood kraft fiber and eucalyptus kraft has a basis weight of about 4 lbs per 3000 sq ft ream; and upper stratum 4-22 comprising primarily eucalyptus APMP has basis weight of 2 to 6 lbs per 3000 sq ft ream. In many cases, it will be preferable to substitute furnishes comprising about 20% CMF; 40% eucalyptus kraft and 40% northern bleached softwood kraft fiber for 50% northern bleached softwood kraft fiber and 50% by weight of eucalyptus kraft in the above. It can be observed that upper ply 4-12 and interior ply 4-18 have been embossed together, while lower ply 4-20 is relatively planar and is preferably unembossed.
Table 23 summarizes CWP prototype properties made using the general strategy shown in FIG. 14 in comparison to some other tissue structures. Product 18 is an example of using an integrated furnish to lower cost through cheaper and bulkier fiber, while maintaining softness. The 176 count roll has a 4.83 inch diameter and a 23% roll compression. Alternatively, basis weight can be taken out of the 160 caliper product to keep 200 sheets, as in, for example, the 31 lb/ream product 19.
Product 24 is a CMF containing prototype offsetting the high cost CMF in the Yankee stratum by low cost integrated furnish away from the surface to produce a tissue achieving an extremely high softness rating of 20 when tested by a trained softness panel. Product 24 is made with an outer ply comprising a 6.7 lb/ream Yankee layer with 20% pilot CMF and 80% eucalyptus kraft with the remaining 6 lb/ream air layer being made with 50% southern softwood kraft and 50% southern hardwood kraft. As the middle ply is an uncalendered sheet with 50% southern softwood and 50% southern hardwood kraft, the finished product content nets out to only 7% CMF, 28% eucalyptus kraft, and 65% southern kraft for a product that is potentially economically feasible in view of the benefits resulting from the use of the CMF.
FIGS. 13 and 15 show plots of softness versus wet lint with the bubble size representing CD wet tensile. Softness greater than 19 was achieved for most CWP prototypes whether they are glue laminated or knurled. Wet lint was very low and wet tensile was generally less than the Delve 358 product, but greater than Charmin® Ultra Strong (69 g/3 in. CDWT). Many prototypes have a combination of softness, low lint, and durability.
It can also be appreciated that prototypes with CMF have less wet lint than comparable prototypes with only wood pulp. Prototypes with just wood pulp, however, have substantially reduced lint relative to other retail products, so they may provide the most economical way of delivering low lint.
Another comparison to highlight is the lower wet lint achieved with glue lamination relative to knurling, particularly, in products without CMF. The bubbles 90 and 116 in FIG. 15 (glue lamination) were made with outer plies similar to the product represented by bubble 315 (glue lamination). One of the knurled products had higher lint attributable to the surface ply failing, while other knurled products were both soft and durable. The difference between these two products was a higher basis weight and strength in the product that did not fail. While all glued products had low lint, most knurled prototypes performed nearly as well.
FIG. 16 compares the dispersibility of previous FRBC prototypes with current CWP. Many CWP products have both dispersibility and low lint, while others fail dispersibility, despite being less durable than FRBC prototypes. This difference between FRBC and CWP can be explained mostly by basis weight, but the data also suggest a fiber composition contribution. CWP prototypes with a value of 2000 shakes were terminated without passing. The samples were observed to be largely disintegrated, but too floccy to pass the small bottle opening in 8 seconds per the procedure. Higher softwood contents will increase the flocciness of the disintegrated tissue, and this effect was often seen in a product that was made with a middle ply with 50% southern pine. On the other hand, sheets with more eucalyptus APMP passed the test. Minimizing softwood content, particularly, southern pine, can benefit dispersibility, particularly, in high basis weight tissue with more durability. Desirably, softwood content will be kept to less than about 40%, more preferably, to less than about 35%, still more preferably, between about 20% and about 35%, and most preferably, to between about 25% and about 35%.
FIG. 17 shows that embossing with pattern HVS 9 (FIGS. 28, 28-A to 28-H, 28-J, 28-1, and 28-2), then ply bonding by knurling, resulted in a softer product on similar sheets than embossing with pattern U 19 (FIGS. 27, 27A to 27F, 27H, and 27T) and joining by glue. The HVS 9 microemboss reduced basesheet tensile on the order of 25%, while there was almost no tensile breakdown with the emboss penetration used in U 19.
FIGS. 18 and 19 compare the attributes of bath tissue made using FRBC technology to tissue made using CWP. In particular, while FRBC clearly has a striking advantage in terms of bulk generation/caliper (FIG. 18), the difference in softness is considerably less substantial (FIG. 19).
Referring back to Table 23, Products 1 and 2 are early prototypes that used birch APMP for the bulky inner layer. It appears that other APMP hardwood pulps can be substituted for eucalyptus APMP in the interior plies of three-ply products to provide the bulk benefit of the eucalyptus APMP. The sheets are, however, weak and subject to considerable dusting, suggesting that they are not all that desirable for exterior plies.
In contrast, the preceding Examples demonstrate that low cost eucalyptus APMP furnish can be incorporated into premium three-ply bath tissue without sacrificing softness or the attributes of quality, while adding bulk. Three-ply CWP can be an acceptable format for a premium quality wet or dry bath tissue.
While the invention has been described in connection with numerous examples and embodiments, modifications to those examples and embodiments within the spirit and scope of the invention will be readily apparent to those of skill in the art. In view of the foregoing discussion, relevant knowledge in the art and references including copending applications discussed above, the relevant disclosures of which are all incorporated herein by reference in their entireties, further description is deemed unnecessary.

## Claims

1. A multi-ply bath tissue having no more than three plies and no fewer than two plies, the multi-ply bath tissue having a basis weight of from about 20 to about 35 lbs per 3000 sq foot ream, and comprising:
(A) from about 3% to about 50% cellulosic microfiber; and
(B) from about 50% to about 97% wood pulp fibers,
the multi-ply bath tissue having:
(a) sufficient temporary wet strength resin to provide an initial Finch Cup cross-machine direction (CD) wet tensile of from about 2.5 to about 20 g/3 in. per pound of basis weight, the initial Finch Cup CD wet tensile decaying to less than 65% of the initial value in less than 15 minutes after immersion in water; and
(b) a caliper of at least 5 mils per 8 sheets per pound of basis weight, wherein at least one of the plies comprises:
(i) a plurality of fiber-enriched hollow domed regions having a relatively high basis weight;
(ii) a plurality of connecting regions having a relatively lower basis weight forming a network interconnecting the fiber-enriched hollow domed regions of the sheet; and
(iii) a plurality of transition regions with upwardly and inwardly inflected consolidated fibrous regions transitioning from the connecting regions into the fiber-enriched hollow domed regions.

2. The multi-ply bath tissue of claim 1, having an opacity of at least about 2.5 MacBeth Opacity Units per pound of basis weight.

3. The multi-ply bath tissue of claim 1, comprising from about 5% to about 25% cellulosic microfiber and from about 75% to about 85% wood pulp fibers.

4. The multi-ply bath tissue of claim 1, comprising two substantially unembossed plies and one embossed ply.

5. The multi-ply bath tissue of claim 1, comprising one substantially unembossed ply and two embossed plies.

6. The multi-ply bath tissue of claim 1, having a basis weight of from about 22 to about 32 lbs per 3000 sq foot ream.

7. The multi-ply bath tissue of claim 1, comprising overall from at least about 5% up to about 50% of cellulosic microfiber (CMF) by weight and from about 50% to about 95% wood pulp fibers, the multi-ply bath tissue comprising three plies, at least one of the plies comprising at least one stratum comprising from about 15% to about 50% of cellulosic microfiber, the multi-ply bath tissue having an eight sheet caliper of at least about 5.25 mils per lb of basis weight for a 3000 sq foot ream, a breaking modulus of between 2.5 and 3.5 g/% stretch per pound of basis weight, a CD wet tensile of between 3.5 and 18 g/3 in. per pound of basis weight, and a geometric mean (GM) dry tensile (GMT) of between 30 and 60 g/3 in. per pound of basis weight.

8. The multi-ply bath tissue of claim 7, wherein:
(i) the ply comprising the plurality of fiber-enriched hollow domed regions, the plurality of connecting regions, and the plurality of transition regions is a ply other than an interior ply, and
(ii) the at least one of the plies comprising the at least one stratum comprising from about 15% to about 50% cellulosic microfiber is disposed such that the stratum defines an exterior surface of the multi-ply bath tissue.

9. The multi-ply bath tissue of claim 7, wherein at least two of the three plies comprise a plurality of fiber-enriched hollow domed regions having a relatively high basis weight, a plurality of connecting regions of a relatively lower basis weight forming a network interconnecting the fiber-enriched hollow domed regions of a sheet of the bath tissue, and a plurality of transition regions with upwardly and inwardly inflected consolidated fibrous regions transitioning from the connecting regions into the fiber-enriched hollow domed regions.

10. The multi-ply bath tissue of claim 7, wherein each of the three plies comprises a plurality of fiber-enriched hollow domed regions having a relatively high basis weight, a plurality of connecting regions of a relatively lower basis weight forming a network interconnecting the fiber-enriched hollow domed regions of the sheet, and a plurality of transition regions with upwardly and inwardly inflected consolidated fibrous regions transitioning from the connecting regions into the fiber-enriched hollow domed regions.

11. The multi-ply bath tissue of claim 1, wherein the fiber-enriched hollow domed regions in the plurality of fiber-enriched hollow domed regions are provided in an interpenetrating staggered array.

12. The multi-ply bath tissue of claim 1, wherein, when tested according to the Wet Abrasion Lint Test, the Wet Abraded Lint Area is less than 35 mm2.

13. The multi-ply bath tissue of claim 1, wherein, when tested according to the Wet Abrasion Lint Test, the Wet Abraded Lint Area is less than 30 mm2.

14. The multi-ply bath tissue of claim 1, wherein, when tested according to the Wet Abrasion Lint Test, the Wet Abraded Lint Area is less than 25 mm2.

15. The multi-ply bath tissue of claim 1, wherein, when tested according to the Wet Abrasion Lint Test, the Wet Abraded Lint Area is less than 20 mm2.

16. The multi-ply bath tissue of claim 1, wherein, when tested according to the Dry Lint Test, the ΔL* value is less than 6.0.

17. The multi-ply bath tissue of claim 1, wherein, when tested according to the Dry Lint Test, the ΔL* value is less than 5.0.

18. The multi-ply bath tissue of claim 1, wherein, when tested according to the Dry Lint Test, the ΔL* value is less than 4.5.

19. The multi-ply bath tissue of claim 1, wherein, when tested according to the Dry Lint Test, the ΔL* value is less than 4.25.

20. The multi-ply bath tissue of claim 1, wherein the plies are joined to each other by knurling.

21. The multi-ply bath tissue of claim 1, wherein the plies are embossed with a pattern having primarily points to the inside and are joined by glue-lamination.

22. The multi-ply bath tissue of claim 1, comprising three plies of tissue, wherein two plies are embossed, one ply is unembossed, and the plies are joined by knurling, wherein knurled regions are arranged in a meandering path.

23. The multi-ply bath tissue of claim 1, comprising three plies of tissue, wherein two plies are unembossed, one ply is embossed, and the plies are joined by knurling, wherein knurled regions are arranged in a meandering path.

24. The multi-ply bath tissue of claim 1, comprising three plies of tissue, wherein two plies are embossed, one ply is unembossed, and the plies are joined by knurling, wherein knurled regions are arranged in a meandering path and an outermost stratum of a lower ply has substantially the same composition as that of an outermost stratum of an upper ply.

25. The multi-ply bath tissue of claim 1, having a geometric mean (GM) dry tensile of from about 17 to about 80 g/3 in. per pound basis weight.

26. The multi-ply bath tissue of claim 1, having a CD dry tensile of between about 30 to about 60 g/3 in. per pound of basis weight.

27. A three-ply bath tissue having a basis weight of from about 20 to about 35 lbs per 3000 sq foot ream, and comprising:
(A) from about 5% to about 25% cellulosic microfiber; and
(B) from about 75% to about 95% wood pulp fibers,
the three-ply bath tissue having:
sufficient temporary wet strength resin to provide an initial Finch Cup cross-machine (CD) wet tensile of from about 2.5 to about 20 g/3 in. per pound of basis weight, the initial Finch Cup CD wet tensile decaying to less than 75% of the initial value in less than 1 hour after immersion in water, wherein at least one of the plies, other than an interior ply, comprises:
(i) a plurality of fiber-enriched hollow domed regions having a relatively high basis weight;
(ii) a plurality of connecting regions having a relatively lower basis weight forming a network interconnecting the fiber-enriched hollow domed regions of the sheet; and
(iii) a plurality of transition regions with upwardly and inwardly inflected consolidated fibrous saddle shaped regions transitioning from the connecting regions into the fiber-enriched hollow domed regions.

28. The three-ply bath tissue of claim 27, having a geometric mean (GM) dry tensile of from about 17 to 80 g/3 in. per pound of basis weight.

29. The three-ply bath tissue of claim 27, having a geometric mean (GM) breaking modulus of between 1.5 to 6.5 g/% stretch per pound of basis weight.

30. The three-ply bath tissue of claim 27, having a CD dry tensile of between about 2 to about 30 g/3 in. per pound of basis weight.

31. The three-ply bath tissue of claim 27, having an opacity of at least about 2.0 MacBeth Opacity Units per pound of basis weight.

32. A multi-ply bath tissue having no more than three-plies and no fewer than two-plies, the multi-ply sheet having a basis weight of from about 20 to about 38 lbs per 3000 sq foot ream, and comprising:
(a) up to about 30% cellulosic microfiber;
(b) from about 70% to about 90% wood pulp fibers; and
(c) from about 5% to about 50% by weight of the tissue comprising eucalyptus fibers having a lignin content of at least about 20%,
the multi-ply bath tissue having:
(i) sufficient temporary wet strength resin to provide an initial Finch Cup cross-machine direction (CD) wet tensile of from about 2.5 to about 20 g/3 in. per pound of basis weight, the initial Finch Cup CD wet tensile decaying to less than 65% of the initial value in less than one half hour after immersion in water; and
(ii) a caliper of at least 4 mils per 8 sheets per pound of basis weight.

33. The multi-ply bath tissue of claim 32, having a geometric mean (GM) dry tensile of from about 35 to 80 g/3 in. per pound of basis weight.

34. The multi-ply bath tissue of claim 32, having a CD dry tensile of between about 2 to about 30 g/3 in. per pound of basis weight.

35. The multi-ply bath tissue of claim 32, having a caliper of at least 4.5 mils per 8 sheets per pound of basis weight.

36. The multi-ply bath tissue of claim 32, having a caliper of at least 5 mils per 8 sheets per pound of basis weight.

37. The multi-ply bath tissue of claim 32, wherein, when tested according to the Wet Abrasion Lint Test, the Wet Abraded Lint Area is less than 35 mm2.

38. The multi-ply bath tissue of claim 32, wherein, when tested according to the Wet Abrasion Lint Test, the Wet Abraded Lint Area is less than 30 mm2.

39. The multi-ply bath tissue of claim 32, wherein, when tested according to the Wet Abrasion Lint Test, the Wet Abraded Lint Area is less than 25 mm2.

40. The multi-ply bath tissue of claim 32, wherein, when tested according to the Wet Abrasion Lint Test, the Wet Abraded Lint Area is less than 20 mm2.

41. The multi-ply bath tissue of claim 32, having an opacity of at least about 2.5 MacBeth Opacity Units per pound of basis weight.

42. The multi-ply bath tissue of claim 32, comprising from about 3% to about 10% cellulosic microfiber and from about 75% to about 85% wood pulp fibers.

43. The multi-ply bath tissue of claim 32, comprising two substantially unembossed plies and one embossed ply.

44. The multi-ply bath tissue of claim 32, comprising one substantially unembossed ply and two embossed plies.

45. The multi-ply bath tissue of claim 32, having a basis weight of from about 22 to about 32 lbs per 3000 sq foot ream.

46. The multi-ply bath tissue of claim 32, comprising three plies, at least the first and second plies of which comprise from about 3% to about 25% cellulosic microfiber, up to about 50% alkaline peroxide mechanical pulp (APMP) eucalyptus and from about 75% to about 97% wood pulp fibers, the multi-ply bath tissue having:
(a) an overall basis weight of between 22 and 36 lbs per 3000 sq ft ream;
(b) an eight sheet caliper of at least about 5.25 mils per lb of basis weight for a 3000 sq foot ream;
(c) a breaking modulus of between 2.5 and 3.5 g/% stretch per pound of basis weight;
(d) a CD wet tensile of between 3 and 18 g/3 in. per pound of basis weight; and
(e) a geometric mean tensile (GMT) of between 40 and 70 g/3 in. per pound of basis weight, wherein the percentage of eucalyptus APMP in the third ply is:
(i) greater than at least about 20%;
(ii) greater than the percentage of eucalyptus APMP in the first ply; and
(iii) exceeds the percentage of eucalyptus APMP in the first ply by an amount that is at least 20% of the weight of eucalyptus APMP in the first ply, if any.

47. The multi-ply bath tissue of claim 46, wherein at least one of the plies comprises a web having a plurality of fiber-enriched hollow domed regions having a relatively high basis weight, a plurality of connecting regions having a relatively lower basis weight forming a network interconnecting the fiber-enriched hollow domed regions of the sheet, and a plurality of transition regions with upwardly and inwardly inflected consolidated fibrous regions transitioning from the connecting regions into the fiber-enriched hollow domed regions.

48. The multi-ply bath tissue of claim 47, wherein the ply comprising the plurality of fiber-enriched hollow domed regions, the plurality of connecting regions, and the plurality of transition regions is a ply other than an interior ply.

49. The multi-ply bath tissue of claim 47, wherein the fiber-enriched hollow domed regions in the plurality of fiber-enriched hollow domed regions are provided in an interpenetrating staggered array.

50. The multi-ply bath tissue of claim 46, wherein at least two of the three plies comprise a plurality of fiber-enriched hollow domed regions having a relatively high basis weight, a plurality of connecting regions having a relatively lower basis weight forming a network interconnecting the fiber-enriched hollow domed regions of the sheet, and a plurality of transition regions with upwardly and inwardly inflected consolidated fibrous regions transitioning from the connecting regions into the fiber-enriched hollow domed regions.

51. The multi-ply bath tissue of claim 46, wherein each of the three plies comprises a plurality of fiber-enriched hollow domed regions having a relatively high basis weight, a plurality of connecting regions having a relatively lower basis weight forming a network interconnecting the fiber-enriched hollow domed regions of the sheet, and a plurality of transition regions with upwardly and inwardly inflected consolidated fibrous regions transitioning from the connecting regions into the fiber-enriched hollow domed regions.

52. The multi-ply bath tissue of claim 46, wherein, when tested according to the Wet Abrasion Lint Test, the Wet Abraded Lint Area is less than 35 mm2.

53. The multi-ply bath tissue of claim 46, wherein, when tested according to the Wet Abrasion Lint Test, the Wet Abraded Lint Area is less than 30 mm2.

54. The multi-ply bath tissue of claim 46, wherein, when tested according to the Wet Abrasion Lint Test, the Wet Abraded Lint Area is less than 25 mm2.

55. The multi-ply bath tissue of claim 46, wherein, when tested according to the Wet Abrasion Lint Test, the Wet Abraded Lint Area is less than 20 mm2.

56. The multi-ply bath tissue of claim 46, wherein, when tested according to the Dry Lint Test, the ΔL* value is less than 6.0.

57. The multi-ply bath tissue of claim 46, wherein, when tested according to the Dry Lint Test, the ΔL* value is less than 5.5.

58. The multi-ply bath tissue of claim 46, wherein, when tested according to the Dry Lint Test, the ΔL* value is less than 5.0.

59. The multi-ply bath tissue of claim 46, wherein the plies are joined to each other by knurling.

60. The multi-ply bath tissue of claim 46, wherein the plies are embossed in a pattern having primarily points to the inside and are joined by glue-lamination.

61. The multi-ply bath tissue of claim 46, comprising three plies of tissue, wherein two plies are embossed, one ply is unembossed, and the plies are joined by knurling, wherein knurled regions are arranged in a meandering path.

62. The multi-ply bath tissue of claim 46, comprising three plies of tissue, wherein two plies are unembossed, one ply is embossed, and the plies are joined by knurling, wherein knurled regions are arranged in a meandering path.

63. The multi-ply bath tissue of claim 46, comprising two plies of tissue, wherein one ply is embossed, one ply is unembossed, and the plies are joined by knurling, wherein knurled regions are arranged in a meandering path.

64. A three-ply bath tissue having a basis weight of from about 20 to 38 lbs per 3000 sq foot ream, and comprising:
(A) from about 15% to about 25% cellulosic microfiber;
(B) from about 78% to about 85% wood pulp fibers; and
(C) from about 10% to about 50% of the weight of the tissue comprising eucalyptus fibers having a lignin content of at least about 20%, an ISO brightness of at least about 84, a Canadian Standard Freeness (CSF) of at least about 400 ml, a bulk of between 2.2 and 4.2 cc/g, and a breaking length of between about 1.2 and 4.7 km,
the three-ply bath tissue having:
sufficient temporary wet strength resin to provide an initial Finch Cup cross-machine direction (CD) wet tensile of from about 2.5 g/3 in. to about 20 g/3 in. per pound of basis weight, the initial Finch Cup CD wet tensile decaying to less than 65% of the initial value in less than one hour after immersion in water, and
wherein at least one of the plies, other than an interior ply, comprises:
(i) a plurality of fiber-enriched hollow domed regions having a relatively high basis weight;
(ii) a plurality of connecting regions having a relatively lower basis weight forming a network interconnecting the fiber-enriched hollow domed regions of the sheet; and
(iii) a plurality of transition regions with upwardly and inwardly inflected consolidated fibrous saddle shaped regions transitioning from the connecting regions into the fiber-enriched hollow domed regions.

65. The three-ply bath tissue of claim 64, wherein at least 50% of the eucalyptus fibers having a lignin content of at least about 20% are never dried fibers.

66. The three-ply bath tissue of claim 64, having a geometric mean (GM) dry tensile of from about 25 to 80 g/3 in. per pound of basis weight.

67. The three-ply bath tissue of claim 64, having a breaking modulus of between 2.5 and 3.5 g/% stretch per pound of basis weight.

68. The three-ply bath tissue of claim 64, having a cross-machine direction (CD) dry tensile of between about 30 to about 60 g/3 in. per pound of basis weight.

69. The three-ply bath tissue of claim 64, having an opacity of at least about 2.5 MacBeth Opacity Units per pound of basis weight.

70. A three-ply bath tissue product having:
(A) an upper stratified ply comprising two strata, an outer stratum and an inner stratum,
(a) the outer stratum comprising a blend of at least about 30% to about 70% kraft fiber and at least 30% to about 70% by weight of eucalyptus kraft and having a basis weight of at least about 5 to about 12 lbs per 3000 sq ft ream; and
(b) the inner stratum comprising at least about 50% fibers having a lignin content of at least about 20% by weight and a basis weight of at least about 2.0 lbs per 3000 sq ft ream;

(B) an interior ply having a basis weight of at least about 6 to about 15 lbs per 3000 sq ft ream, comprising:
(a) at least about 30% to about 70% fibers having a lignin content of at least about 20% by weight; and
(b) from at least about 30% to about 70% by weight of bleached softwood kraft fibers; and

(C) a lower stratified ply comprising two strata, a first stratum and a second stratum,
(a) the first stratum comprising from at least about 30% to about 70% kraft fiber and from about 30% to about 70% by weight of eucalyptus kraft and having a basis weight of about 5 to about 12 lbs per 3000 sq ft ream; and
(b) the second stratum comprising at least about 50% fibers having a lignin content of at least about 20% by weight and a basis weight of at least about 2.0 lbs per 3000 sq ft ream,

wherein at least one of the plies comprises:
(i) a plurality of fiber-enriched hollow domed regions having a relatively high basis weight;
(ii) a plurality of connecting regions having a relatively lower basis weight forming a network interconnecting the fiber-enriched hollow domed regions of the sheet; and
(iii) a plurality of transition regions with upwardly and inwardly inflected consolidated fibrous saddle shaped regions transitioning from the connecting regions into the fiber-enriched hollow domed regions.

71. The three-ply bath tissue product of claim 70, wherein at least 50% of the fibers having a lignin content of at least about 20% are never dried fibers.

72. The three-ply bath tissue product of claim 71, wherein the outer stratum of the upper ply comprises at least about 8% by weight of individualized regenerated cellulosic microfiber.

73. The three-ply bath tissue product of claim 71, wherein the outer stratum of the upper ply comprises at least about 8% by weight of individualized regenerated cellulosic microfiber having a number average diameter of at most about 2 microns.

74. The three-ply bath tissue product of claim 70, wherein the interior ply and the upper stratified ply have been joined by being embossed together.

75. The three-ply bath tissue product of claim 74, wherein the fibrous composition of the upper stratified ply is substantially the same as the fibrous composition of the lower stratified ply.

76. The three-ply bath tissue product of claim 74, wherein the depth of emboss of the lower stratified ply is less than 50% of the depth of emboss of the upper stratified ply.

77. The three-ply bath tissue product of claim 74, wherein the depth of emboss of the lower stratified ply is less than 80% of the depth of emboss of the upper stratified ply.

78. The three-ply bath tissue product of claim 76, wherein the outer stratum of the upper stratified ply comprises at least about 8% by weight of individualized regenerated cellulosic microfiber having a number average diameter of at most about 2 microns.

79. The three-ply bath tissue product of claim 74, wherein the lower stratified ply is generally unembossed.

80. The three-ply bath tissue product of claim 79, wherein the outer stratum of the upper stratified ply comprises at least about 5% by weight of individualized regenerated cellulosic microfiber having a number average diameter of at most about 1 micron.

81. The three-ply bath tissue product of claim 70, wherein the fibrous composition of the upper stratified ply is substantially the same as the fibrous composition of the lower stratified ply.

82. The three-ply bath tissue product of claim 70, wherein the outer stratum of the upper stratified ply further comprises at least about 5% by weight of individualized regenerated cellulosic microfiber having a diameter of no more than about 5 microns and passing a screen of about 14 mesh.

83. The three-ply bath tissue product of claim 70, wherein the outer stratum of the upper stratified ply further comprises at least about 5% by weight of individualized regenerated cellulosic microfiber having a number average diameter of no more than about 4 microns and a number average length of between about 50 microns and 2000 microns.

84. The three-ply bath tissue product of claim 70, wherein the outer stratum of the upper stratified ply further comprises at least about 10% by weight of individualized regenerated cellulosic microfiber having a number average diameter of at most about 4 microns and a number average length of between about 50 microns and 2000 microns.

85. The three-ply bath tissue product of claim 70, wherein the outer stratum of the upper stratified ply further comprises at least about 10% by weight of individualized regenerated cellulosic microfiber having a number average diameter of at most about 2 microns and a number average length of between about 50 microns and 2000 microns.

86. The three-ply bath tissue product of claim 70, wherein the outer stratum of each of the upper stratifed ply and the lower stratified ply further comprises at least about 5% by weight of individualized regenerated cellulosic microfiber having a number average diameter of at most about 4 microns and a number average length of between about 50 microns and 2000 microns.

87. The three-ply bath tissue product of claim 70, wherein each of the inner stratum of the upper stratified ply and the second stratum of the lower stratified ply comprises at least about 70% eucalyptus fibers having a lignin content of at least about 20% by weight.

88. The three-ply bath tissue product of claim 70, wherein each of the inner stratum of the upper stratified ply and the second stratum of the lower stratified ply comprises debonder.

89. The three-ply bath tissue product of claim 70, wherein the interior ply is creped, exhibiting a percent crepe at least 3% greater than that of the upper stratified and lower stratified plies.

90. A three-ply bath tissue product comprising:
(A) an upper stratified ply comprising two strata, an outer stratum and an inner stratum,
(a) the outer stratum comprising a blend of at least about 30% to about 70% kraft fiber and at least 30% to about 70% by weight of eucalyptus kraft and at least about 5% by weight of individualized regenerated cellulosic microfiber having a number average diameter of at most about 4 microns and a number average length of between about 50 microns and 2000 microns, the outer stratum having a basis weight of at least about 5 to about 12 lbs per 3000 sq ft ream; and
(b) the inner stratum comprising at least about 70% fibers having a lignin content of at least about 20% by weight, and a basis weight of at least about 2.0 lbs per 3000 sq ft ream;

(B) an interior ply having a basis weight of at least about 6 to about 15 lbs per 3000 sq ft ream, and comprising:
(a) at least about 40% to about 90% fibers having a lignin content of at least about 20% by weight; and
(b) from at least about 10% to about 60% by weight of bleached kraft fiber; and

(C) a lower stratified ply comprising at least two strata, including a first stratum and a second stratum,
(a) the first stratum comprising from at least about 30% to about 70% kraft fiber and from about 30% to about 70% by weight of eucalyptus kraft and having a basis weight of about 5 to about 12 lbs per 3000 sq ft ream; and
(b) the second stratum comprising at least about 70% fibers having a lignin content of at least about 20% by weight and a basis weight of at least about 2.0 lbs per 3000 sq ft ream,

wherein at least one of the plies, other than the interior ply, comprises:
(i) a plurality of fiber-enriched hollow domed regions having a relatively high basis weight;
(ii) a plurality of connecting regions having a relatively lower basis weight forming a network interconnecting the fiber-enriched hollow domed regions of the sheet; and
(iii) a plurality of transition regions with upwardly and inwardly inflected consolidated fibrous saddle shaped regions transitioning from the connecting regions into the fiber-enriched hollow domed regions.

91. The three-ply bath tissue product of claim 90, wherein the upper stratified ply and the lower stratified ply have substantially identical fibrous compositions.

92. The three-ply bath tissue product of claim 90, exhibiting an ISO brightness of at least:


0.82×(% VCP)+0.795×(% RF)98+0.84×(% APMP+CFM),

where % VCP is the percentage of virgin chemical pulp in a sheet in an outer ply, % RF, the percentage of recycle fiber in the outer ply, and % APMP+CMF is the percentage of alkaline peroxide mechanical pulp (APMP) eucalyptus and regenerated cellulosic microfiber in the outer ply.

93. The three-ply bath tissue product of claim 90, wherein a major portion of the fibers in the interior ply is never dried fibers having a lignin content of at least about 23%, and exhibits an ISO brightness of at least about 82.

94. The three-ply bath tissue product of claim 90, wherein the weight percentage of chemically pulped softwood fiber in the three-ply bath tissue product is limited to at most 30% of the weight of the three-ply bath tissue product.

95. The three-ply bath tissue product of claim 90, wherein a major portion of the fibers in the interior ply has a lignin content of at least about 23%, and exhibits an ISO brightness of at least about 82.

96. A multi-ply bath tissue having a basis weight of from about 20 to about 40 lbs per 3000 sq foot ream, and comprising:
(A) from about 3% to about 50% cellulosic microfiber; and
(B) from about 50% to about 97% wood pulp fibers,
the multi-ply bath tissue having:
(a) sufficient temporary wet strength resin to provide an initial Finch Cup cross-machine direction (CD) wet tensile of from about 2.5 to about 20 g/3 in. per pound of basis weight, the initial Finch Cup CD wet tensile decaying to less than 65% of the initial value in less than 15 minutes after immersion in water; and
(b) a caliper of at least 5 mils per 8 sheets per pound of basis weight,
wherein at least one of the plies comprises:
(i) a plurality of fiber-enriched hollow domed regions having a relatively high basis weight;
(ii) a plurality of connecting regions having a relatively lower basis weight forming a network interconnecting the fiber-enriched hollow domed regions of the sheet; and
(iii) a plurality of transition regions with upwardly and inwardly inflected consolidated fibrous regions transitioning from the connecting regions into the fiber-enriched hollow domed regions.

97. The multi-ply bath tissue of claim 96, having an opacity of at least about 2.5 MacBeth Opacity Units per pound of basis weight.

98. The multi-ply bath tissue of claim 96, comprising from about 5% to about 25% cellulosic microfiber and from about 75% to about 85% wood pulp fibers.

99. The multi-ply bath tissue of claim 96, having a basis weight of from about 22 to about 32 lbs per 3000 sq foot ream.

100. The multi-ply bath tissue of claim 96, wherein, when tested according to the Wet Abrasion Lint Test, the Wet Abraded Lint Area is less than 35 mm2.

101. The multi-ply bath tissue of claim 96, wherein, when tested according to the Wet Abrasion Lint Test, the Wet Abraded Lint Area is less than 30 mm2.

102. The multi-ply bath tissue of claim 96, wherein, when tested according to the Wet Abrasion Lint Test, the Wet Abraded Lint Area is less than 25 mm2.

103. The multi-ply bath tissue of claim 96, wherein, when tested according to the Wet Abrasion Lint Test, the Wet Abraded Lint Area is less than 20 mm2.

104. The multi-ply bath tissue of claim 96, wherein, when tested according to the Dry Lint Test, the ΔL* value is less than 6.0.

105. The multi-ply bath tissue of claim 96, wherein, when tested according to the Dry Lint Test, the ΔL* value is less than 5.0.

106. The multi-ply bath tissue of claim 96, wherein, when tested according to the Dry Lint Test, the ΔL* value is less than 4.5.

107. The multi-ply bath tissue of claim 96, wherein, when tested according to the Dry Lint Test, the ΔL* value is less than 4.25.

108. The multi-ply bath tissue of claim 96, wherein the plies are joined to each other by knurling.

109. The multi-ply bath tissue of claim 96, wherein the plies are embossed with a pattern having primarily points to the inside and are joined by glue-lamination.

110. The multi-ply bath tissue of claim 96, having a geometric mean (GM) dry tensile of from about 17 to 80 g/3 in. per pound of basis weight.

111. The multi-ply bath tissue of claim 96, having a CD dry tensile of between about 30 to about 60 g/3 in. per pound of basis weight.

112. A bath tissue having a basis weight of from about 20 to about 40 lbs per 3000 sq foot ream, and comprising:
(A) from about 3% to about 50% cellulosic microfiber; and
(B) from about 50% to about 97% wood pulp fibers,
the bath tissue having:
sufficient temporary wet strength resin to provide an initial Finch Cup cross-machine direction (CD) wet tensile of from about 2.5 to about 20 g/3 in. per pound of basis weight, the initial Finch Cup CD wet tensile decaying to less than 65% of the initial value in less than 15 minutes after immersion in water, wherein the bath tissue includes at least one ply comprising:
(i) a plurality of fiber-enriched hollow domed regions having a relatively high basis weight;
(ii) a plurality of connecting regions having a relatively lower basis weight forming a network interconnecting the fiber-enriched hollow domed regions of the sheet; and
(iii) a plurality of transition regions with upwardly and inwardly inflected consolidated fibrous regions transitioning from the connecting regions into the fiber-enriched hollow domed regions.

113. The bath tissue of claim 112, having an opacity of at least about 2.5 MacBeth Opacity Units per pound of basis weight.

114. The bath tissue of claim 112, comprising from about 5% to about 25% cellulosic microfiber and from about 75% to about 85% wood pulp fibers.

115. The bath tissue of claim 112, having a basis weight of from about 22 to about 32 lbs per 3000 sq foot ream.

116. The bath tissue of claim 112, wherein, when tested according to the Wet Abrasion Lint Test, the Wet Abraded Lint Area is less than 35 mm2.

117. The bath tissue of claim 112, wherein, when tested according to the Wet Abrasion Lint Test, the Wet Abraded Lint Area is less than 30 mm2.

118. The bath tissue of claim 112, wherein, when tested according to the Wet Abrasion Lint Test, the Wet Abraded Lint Area is less than 25 mm2.

119. The bath tissue of claim 112, wherein, when tested according to the Wet Abrasion Lint Test, the Wet Abraded Lint Area is less than 20 mm2.

120. The bath tissue of claim 112, wherein, when tested according to the Dry Lint Test, the ΔL* value is less than 6.0.

121. The bath tissue of claim 112, wherein, when tested according to the Dry Lint Test, the ΔL* value is less than 5.0.

122. The bath tissue of claim 112, wherein, when tested according to the Dry Lint Test, the ΔL* value is less than 4.5.

123. The bath tissue of claim 112, wherein, when tested according to the Dry Lint Test, the ΔL* value is less than 4.25.

124. The bath tissue of claim 112, having a geometric mean (GM) dry tensile of from about 17 to 80 g/3 in. per pound of basis weight.

125. The bath tissue of claim 112, having a CD dry tensile of between about 30 to about 60 g/3 in. per pound of basis weight.

126. The bath tissue of claim 112, having a caliper of at least 5 mils per 8 sheets per pound of basis weight.