(19)
(11)EP 3 581 710 A1

(12)EUROPEAN PATENT APPLICATION

(43)Date of publication:
18.12.2019 Bulletin 2019/51

(21)Application number: 19185250.8

(22)Date of filing:  08.06.2016
(51)Int. Cl.: 
D21F 11/00  (2006.01)
D21F 11/14  (2006.01)
(84)Designated Contracting States:
AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR
Designated Extension States:
BA ME
Designated Validation States:
MA MD

(30)Priority: 08.06.2015 US 201562172659 P
07.06.2016 US 201615175949

(62)Application number of the earlier application in accordance with Art. 76 EPC:
16729481.8 / 3303694

(71)Applicant: GPCP IP Holdings LLC
Atlanta, Georgia 30303 (US)

(72)Inventors:
  • SZE, Daniel H.
    Appleton, WI 54915 (US)
  • FAN, Xiaolin
    Appleton, WI 54913 (US)
  • CHOU, Hung Liang
    Neenah, WI 54956 (US)
  • ORIARAN, Taiye Philips
    Appleton, WI 54911 (US)
  • ANAND, Farminder Singh
    Appleton, WI 54913 (US)
  • BAUMGARTNER, Dean Joseph
    Bonduel, WI 54107 (US)
  • MILLER, Joseph Henry
    Neenah, WI 54956 (US)

(74)Representative: Grünecker Patent- und Rechtsanwälte PartG mbB 
Leopoldstraße 4
80802 München
80802 München (DE)

 
Remarks:
This application was filed on 09.07.2019 as a divisional application to the application mentioned under INID code 62.
 


(54)METHOD OF MAKING SOFT ABSORBENT SHEETS


(57) Soft absorbent sheets, structuring fabrics for producing soft absorbent sheets, and methods of making soft absorbent sheets. The soft absorbent sheets have a plurality of domed regions or projected regions extending from a surface of the sheets, and connecting regions form a network between domed regions. The domed and projected regions include indented bars that extend across the domed and projected regions in a substantially cross machine direction of the absorbent sheets. The absorbent sheets can be formed by structuring fabrics that have long warp yarn knuckles.




Description

CROSS REFERENCE TO RELATED APPLICATION



[0001] This application is based on U.S. Provisional Patent Application Number 62/172,659, filed June 8, 2015, which is incorporated by reference herein in its entirety.

BACKGROUND


Field of the Invention



[0002] Our invention relates to paper products such as absorbent sheets. Our invention also relates to methods of making paper products such as absorbent sheets, as well as to structuring fabrics for making paper products such as absorbent sheets.

Related Art



[0003] The use of fabrics is well known in the papermaking industry for imparting structure to paper products. More specifically, it is well known that a shape can be provided to paper products by pressing a malleable web of cellulosic fibers against a fabric and then subsequently drying the web. The resulting paper products are thereby formed with a molded shape corresponding to the surface of the fabric. The resulting paper products also thereby have characteristics resulting from the molded shape, such as a particular caliper and absorbency. As such, a myriad of structuring fabrics has been developed for use in papermaking processes to provide products with different shapes and characteristics. And, fabrics can be woven into a near limitless number of patterns for potential use in papermaking processes.

[0004] One important characteristic of many absorbent paper products is softness-consumers want, for example, soft paper towels. Many techniques for increasing the softness of paper products, however, have the effect of reducing other desirable properties of the paper products. For example, calendering basesheets as part of a process for producing paper towels can increase the softness of the resulting paper towels, but calendering also has the effect of reducing the caliper and absorbency of the paper towels. On the other hand, many techniques for improving other important properties of paper products have the effect of reducing the softness of the paper products. For example, wet and dry strength resins can improve the underlying strength of paper products, but wet and dry strength resins also reduce the perceived softness of the products.

[0005] For these reasons, it is desirable to make softer paper products, such as absorbent sheets. And, it is desirable to be able to make such softer absorbent sheets through manipulation of a structuring fabric used in the process of making the absorbent sheets.

SUMMARY OF THE INVENTION



[0006] According to one aspect, our invention provides an absorbent sheet of cellulosic fibers that has a first side and a second side. The absorbent sheet includes a plurality of domed regions projecting from the first side of the sheet, with each of the domed regions including a plurality of indented bars extending across a respective domed region in a substantially cross machine direction (CD) of the absorbent sheet. Connecting regions form a network interconnecting the domed regions of the absorbent sheet.

[0007] According to another aspect, our invention provides an absorbent sheet of cellulosic fibers that has a first side and a second side. The absorbent sheet includes a plurality of domed regions projecting from the first side of the sheet, wherein each domed region is positioned adjacent to another domed region such that a staggered line of domed regions extends substantially along the MD of the absorbent sheet. The absorbent sheet also includes connecting regions forming a network interconnecting the domed regions of the absorbent sheet, wherein each connecting region is substantially continuous with two other connecting regions such that substantially continuous lines of connecting regions extend in a stepped manner along the MD of the absorbent sheet.

[0008] According to yet another aspect, our invention provides an absorbent sheet of cellulosic fibers that has a first side and a second side. The absorbent sheet includes a plurality of domed regions projecting from the first side of the sheet, with each of the domed regions extending a distance of at least about 2.5 mm in the MD of the absorbent sheet. Each of the plurality of domed regions includes an indented bar extending across a respective domed region in a substantially CD of the absorbent sheet, with the indented bar extending a depth of at least about 45 microns below the adjacent portions of the domed region. Further, connecting regions form a network interconnecting the domed regions of the absorbent sheet.

[0009] According to still another aspect, our invention provides a method of making a paper product. The method includes forming an aqueous cellulosic web on a structuring fabric in a papermaking machine, with the structuring fabric including knuckles formed on warp yarns of the structuring fabric, and with the knuckles having a length in the MD of the absorbent sheet and a width in the CD of the absorbent sheet. A planar volumetric density index of the structuring fabric multiplied by the ratio of the length of the knuckles and the width of the knuckles width is about 43 to about 50. The method further includes steps of dewatering the cellulosic web on the structuring fabric, and subsequently drying the cellulosic web to form the absorbent sheet.

[0010] According to a further aspect, our invention provides an absorbent cellulosic sheet that has a first side and a second side, with the absorbent sheet including projected regions extending from the first side of the sheet. The projected regions extend substantially in the MD of the absorbent sheet, with each of the projected regions including a plurality of indented bars extending across the projected regions in a substantially CD of the absorbent sheet, and with the projected regions being substantially parallel to each other. Connecting regions are formed between the projected regions, with the connecting regions extending substantially in the MD.

[0011] According to yet another aspect, our invention provides a method of making a fabric-creped absorbent cellulosic sheet. The method includes compactively dewatering a papermaking furnish to form a web having a consistency of about 30 percent to about 60 percent. The web is creped under pressure in a creping nip between a transfer surface and a structuring fabric. The structuring fabric includes knuckles formed on warp yarns of the structuring fabric, with the knuckles having a length in the machine direction (MD) of the absorbent sheet and a width in the cross machine direction (CD) of the absorbent sheet. A planar volumetric density index of the structuring fabric multiplied by the ratio of the length of the knuckles and the width of the knuckles width is at least about 43. The method also includes drying the web to form the absorbent cellulosic sheet.

[0012] According to one further aspect, our invention provides a method of making a fabric-creped absorbent cellulosic sheet. The method includes compactively dewatering a papermaking furnish to form a web. The web is creped under pressure in a nip between a transfer surface and a structuring fabric. The structuring fabric has machine direction (MD) yarns that form (i) knuckles extending in substantially MD lines along the structuring fabric, and (ii) substantially continuous lines of pockets extending in substantially MD lines along the structuring fabric between the lines of knuckles. The structuring fabric also has cross machine direction (CD) yarns that are completely located below a plane defined by the knuckles of the MD yarns. The method also includes drying the web to form the absorbent cellulosic sheet.

[0013] According to yet another aspect, our invention provides a method of making a fabric-creped absorbent cellulosic sheet. The method includes compactively dewatering a papermaking furnish to form a web having a consistency of about 30 percent to about 60 percent. The method further includes creping the web under pressure in a creping nip between a transfer surface and a structuring fabric and drying the web to form the absorbent cellulosic sheet. The absorbent sheet has SAT capacities of at least about 9.5 g/g and at least about 500 g/m2. Further, a creping ratio is defined by the speed of the transfer surface relative to the speed of the structuring fabric, and the creping ratio is less than about 25%.

BRIEF DESCRIPTION OF THE DRAWINGS



[0014] 

Figure 1 is a schematic diagram of a papermaking machine configuration that can be used in conjunction with our invention.

Figure 2 is a top view of a structuring fabric for making paper products according to an embodiment our invention.

Figures 3A-3F indicate characteristics of structuring fabrics according to embodiments of our invention and characteristics of comparison structuring fabrics.

Figures 4A-4E are photographs of absorbent sheets according to embodiments of our invention.

Figure 5 is an annotated version of the photograph shown in Figure 4E.

Figures 6A and 6B are cross-sectional views of a portion of an absorbent sheet according to an embodiment of our invention and a portion of a comparison absorbent sheet, respectively.

Figures 7A and 7B show laser scans for determining the profile of portions of absorbent sheets according to embodiments of our invention.

Figure 8 indicates characteristics of structuring fabrics according to embodiments of our invention and a comparison structuring fabric.

Figure 9 shows the characteristics of basesheets that were made using the structuring fabrics characterized in Figure 8.

Figures 10A-10D indicate characteristics of still further structuring fabrics according to embodiments of our invention.

Figures 11A-11E are photographs of absorbent sheets according to embodiments of our invention.

Figures 12A-12E are photographs of further absorbent sheets according to embodiments of our invention.

Figure 13 indicates characteristics of structuring fabrics according to embodiments of our invention and a comparison structuring fabric.

Figure 14 shows a measurement of a profile along one of the warp yarns of a structuring fabric according to an embodiment of our invention.

Figure 15 is a chart showing fabric crepe percentage versus caliper for basesheets made with a fabric according to an embodiment of our invention and a comparative fabric.

Figure 16 is a chart showing fabric crepe percentage versus SAT capacity for basesheets made with a fabric according to an embodiment of our invention and a comparative fabric.

Figure 17 is a chart showing fabric crepe percentage versus caliper for basesheets made with different furnishes and a fabric according to an embodiment of our invention.

Figure 18 is a chart showing fabric crepe percentage versus SAT capacity for basesheets made with different furnishes and a fabric according to an embodiment of our invention.

Figure 19 is a chart showing fabric crepe percentage versus void volume for basesheets made with a fabric according to an embodiment of our invention and a comparative fabric.

Figures 20(a) and 20(b) are soft x-ray images of an absorbent sheet according to an embodiment of our invention.

Figures 21(a) and 21(b) are soft x-ray images of an absorbent sheet according to another embodiment of our invention.

Figures 22(a)-22(e) are photographs of absorbent sheets according to further embodiments of our invention.

Figures 23(a) and 23(b) are photographs of an absorbent sheet according to an embodiment of our invention and a comparison absorbent sheet.

Figure 24(a) and 24(b) are photographs of cross sections of the absorbent sheets shown in Figures 23(a) and 23(b).


DETAILED DESCRIPTION OF THE INVENTION



[0015] Our invention relates to paper products such as absorbent sheets and methods of making paper products such as absorbent sheets. Absorbent paper products according to our invention have outstanding combinations of properties that are superior to other absorbent paper products that are known in the art. In some specific embodiments, the absorbent paper products according to our invention have combinations of properties particularly well suited for absorbent hand towels, facial tissues, or toilet paper.

[0016] The term "paper product," as used herein, encompasses any product incorporating papermaking fibers having cellulose as a major constituent. This would include, for example, products marketed as paper towels, toilet paper, facial tissue, etc. Papermaking fibers include virgin pulps or recycled (secondary) cellulosic fibers, or fiber mixes comprising cellulosic fibers. Wood fibers include, for example, those obtained from deciduous and coniferous trees, including softwood fibers, such as northern and southern softwood kraft fibers, and hardwood fibers, such as eucalyptus, maple, birch, aspen, or the like. Examples of fibers suitable for making the products of our invention include non-wood 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.

[0017] "Furnishes" and like terminology refers to aqueous compositions including papermaking fibers, and, optionally, wet strength resins, debonders, and the like, for making paper products. A variety of furnishes can be used in embodiments of our invention, and specific furnishes are disclosed in the examples discussed below. In some embodiments, furnishes are used according to the specifications described in U.S. Patent No. 8,080,130 (the disclosure of which is incorporated by reference in its entirety). The furnishes in this patent include, among other things, cellulosic long fibers having a coarseness of at least about 15.5 mg/100 mm. Examples of furnishes are also specified in the examples discussed below.

[0018] As used herein, the initial fiber and liquid mixture that is dried to a finished product in a papermaking process will be referred to as a "web" and/or a "nascent web." The dried, single-ply product from a papermaking process will be referred to as a "basesheet." Further, the product of a papermaking process may be referred to as an "absorbent sheet." In this regard, an absorbent sheet may be the same as a single basesheet. Alternatively, an absorbent sheet may include a plurality of basesheets, as in a multi-ply structure. Further, an absorbent sheet may have undergone additional processing after being dried in the initial basesheet forming process in order to form a final paper product from a converted basesheet. An "absorbent sheet" includes commercial products marketed as, for example, hand towels.

[0019] When describing our invention herein, the terms "machine direction" (MD) and "cross machine direction" (CD) will be used in accordance with their well-understood meaning in the art. That is, the MD of a fabric or other structure refers to the direction that the structure moves on a papermaking machine in a papermaking process, while CD refers to a direction crossing the MD of the structure. Similarly, when referencing paper products, the MD of the paper product refers to the direction on the product that the product moved on the papermaking machine in the papermaking process, and the CD of the product refers to the direction crossing the MD of the product.

[0020] Figure 1 shows an example of a papermaking machine 200 that can be used to make paper products according to our invention. A detailed description of the configuration and operation of papermaking machine 200 can be found in U.S. Patent No. 7,494,563 ("the '563 patent"), the disclosure of which is incorporated by reference in its entirety. Notably, the '563 patent describes a papermaking process that does not use through air drying (TAD). The following is a brief summary of a process for forming an absorbent sheet using papermaking machine 200.

[0021] The papermaking machine 200 is a three-fabric loop machine that includes a press section 100 in which a creping operation is conducted. Upstream of the press section 100 is a forming section 202. The forming section 202 includes headbox 204 that deposits an aqueous furnish on a forming wire 206 supported by rolls 208 and 210, thereby forming an initial aqueous cellulosic web 116. The forming section 202 also includes a forming roll 212 that supports a papermaking felt 102 such that web 116 is also formed directly on the felt 102. The felt run 214 extends about a suction turning roll 104 and then to a shoe press section 216 wherein the web 116 is deposited on a backing roll 108. The web 116 is wet-pressed concurrently with the transfer to the backing roll 108, which carries the web 116 to a creping nip 120. In other embodiments, however, instead of being transferred on the backing roll 108, the web 116 by be transferred from the felt run 214 onto an endless belt in a dewatering nip, with the endless belt then carrying the web 116 to the creping nip 120. An example of such a configuration can be seen in U.S. Patent No. 8,871,060, which is incorporated by reference herein in its entirety.

[0022] The web 116 is transferred onto the structuring fabric 112 in the creping nip 120, and then vacuum drawn by vacuum molding box 114. After this creping operation, the web 116 is deposited on Yankee dryer 218 in another press nip 217 using a creping adhesive. The web 116 is dried on Yankee dryer 218, which is a heated cylinder, and the web 116 is also dried by high jet velocity impingement air in the Yankee hood around the Yankee dryer 218. As the Yankee dryer 218 rotates, the web 116 is peeled from the dryer 218 at position 220. The web 116 may then be subsequently wound on a take-up reel (not shown). The reel may be operated slower than the Yankee dryer 218 at steady-state in order to impart a further crepe to the web. Optionally, a creping doctor blade 222 may be used to conventionally dry-crepe the web 116 as it is removed from the Yankee dryer 218.

[0023] In a creping nip 120, the web 116 is transferred onto the top side of the structuring fabric 112. The creping nip 120 is defined between the backing roll 108 and the structuring fabric 112, with the structuring fabric 112 being pressed against the backing roll 108 by the creping roll 110. Because the web still has a high moisture content when it is transferred to the structuring fabric 112, the web is deformable such that portions of the web can be drawn into pockets formed between the yarns that make up the structuring fabric 112. (The pockets of structuring fabrics will be described in detail below.) In particular papermaking processes, the structuring fabric 112 moves more slowly than the papermaking felt 102. Thus, the web 116 is creped as it is transferred onto the structuring fabric 112.

[0024] An applied suction from vacuum molding box 114 may also aid in drawing the web 116 into pockets in the surface of the structuring fabric 112, as will be described below. When traveling along the structuring fabric 112, the web 116 reaches a highly consistent state with most of the moisture having been removed. The web 116 is thereby more or less permanently imparted with a shape by the structuring fabric 112, with the shape including domed regions where the web 116 is drawn into the pockets of the structuring fabric 112.

[0025] Basesheets made with papermaking machine 200 may also be subjected to further processing, as is known in the art, in order to convert the basesheets into specific products. For example, the basesheets may be embossed, and two basesheets can be combined into multi-ply products. The specifics of such converting processes are well known in the art.

[0026] Using the process described in the aforementioned '563 patent, the web 116 is dewatered to the point that it has a higher consistency when transferred onto the top side of the structuring fabric 112 compared to an analogous operation in other papermaking processes, such as a TAD process. That is, the web 116 is compactively dewatered so as to have from about 30 percent to about 60 percent consistency (i.e., solids content) before entering the creping nip 120. In the creping nip 120, the web is subjected to a load of about 30 PLI to about 200 PLI. Further, there is a speed differential between the backing roll 108 and the structuring fabric 112. This speed differential is referred to as the fabric creping percentage, and may be calculated as:

where S1 is the speed of the backing roll 108 and S2 is the speed of the structuring fabric 112. In particular embodiments, the fabric crepe percentage can be anywhere from about 3% to about 100%. This combination of web consistency, velocity delta occurring at the creping nip, the pressure employed at the creping nip 120, and the structuring fabric 112 and nip 120 geometry act to rearrange the cellulose fibers while the web 116 is still pliable enough to undergo structural change. In particular, without intending to be bound by theory, it is believed that the slower forming surface speed of the structuring fabric 112 causes the web 116 to be substantially molded into openings in the structuring fabric 116, with the fibers being realigned in proportion to the creping ratio.

[0027] While a specific process has been described in conjunction with the papermaking machine 200, those skilled in the art will appreciate that our invention disclosed herein is not limited to the above-described papermaking process. For example, as opposed to the non-TAD process described above, our invention could be related to a TAD papermaking process. An example of a TAD papermaking process can be seen in U.S. Patent No. 8,080,130, the disclosure of which is incorporated by reference in its entirety.

[0028] Figure 2 is a drawing showing details of a portion of the web contacting side of the structuring fabric 300 that has a configuration for forming paper products according to an embodiment of our invention. The fabric 300 includes warp yarns 302 that run in the machine direction (MD) when the fabric is used in a papermaking process, and weft yarns 304 that run in the cross machine direction (CD). The warp and weft yarns 302 and 304 are woven together so as to form the body of the structuring fabric 300. The web-contacting surface of the structuring fabric 300 is formed by knuckles (two of which are outlined in Figure 2 and labeled as 306 and 310), which are formed on the warp yarns 302, but no knuckles are formed on the weft yarns 304. It should be noted, however, that while the structuring fabric 300 shown in Figure 2 only has knuckles on the warp yarns 302, our invention is not limited to structuring fabrics that only have warp knuckles, but rather, includes fabrics that have both warp and weft knuckles. Indeed, fabrics with only warp knuckles and fabrics with both warp and weft knuckles will be described in detail below.

[0029] The knuckles 306 and 310 in fabric 300 are in a plane that makes up the surface that the web 116 contacts during a papermaking operation. Pockets 308 (one of which is shown as the outlined area in Figure 2) are defined in the areas between the knuckles 306 and 310.

[0030] Portions of the web 116 that do not contact the knuckles 306 and 310 are drawn into the pockets 308 as described above. It is the portions of the web 116 that are drawn into the pockets 308 that result in domed regions that are found in the resulting paper products.

[0031] Those skilled in the art will appreciate the significant length of warp yarn knuckles 306 and 310 in the MD of structuring fabric 300, and will further appreciate that the fabric 300 is configured such that the long warp yarn knuckles 306 and 310 delineate long pockets in the MD. In particular embodiments of our invention, the warp yarn knuckles 306 and 310 have a length of about 2 mm to about 6 mm. Most structuring fabrics known in the art have shorter warp yarn knuckles (if the fabrics have any warp yarn knuckles at all). As will be described below, the longer warp yarn knuckles 306 and 310 provide for a larger contact area for the web 116 during the papermaking process, and, it is believed, might be at least partially responsible for the increased softness seen in absorbent sheets according to our invention, as compared to absorbent sheets with conventional, shorter warp yarn knuckles.

[0032] To quantify the parameters of the structuring fabrics described herein, the fabric characterization techniques described in U.S. Patent Application Publication Nos. 2014/0133734; 2014/0130996; 2014/0254885, and 2015/0129145 (hereafter referred to as the "fabric characterization publications") can be used. The disclosures of the fabric characterization publications are incorporated by reference in their entirety. Such fabric characterization techniques allow for parameters of a structuring fabric to be easily quantified, including knuckle lengths and widths, knuckle densities, pocket areas, pocket densities, pocket depths, and pocket volumes.

[0033] Figures 3A-3E indicate some of the characteristics of structuring fabrics made according to embodiments of our invention, which are labeled as Fabrics 1-15. Figure 3F also shows characteristics of conventional structuring fabrics, which are labeled as Fabrics 16 and 17. Structuring fabrics of the type shown in Figures 3A-3F can be made by a numerous manufacturers, including Albany International of Rochester, New Hampshire and Voith GmbH of Heidenheim, Germany. Fabrics 1-15 have long warp yarn knuckle fabrics such that the vast majority of the contact area in Fabrics 1-15 comes from the warp yarn knuckles, as opposed to weft yarn knuckles (if the fabrics have any weft yarn knuckles at all). Fabrics 16 and 17, which have shorter warp yarn knuckles, are provided for comparison. All of the characteristics shown in Figures 3A-3F were determined using the techniques in the aforementioned fabric characterization publications, particularly, using the non-rectangular, parallelogram calculation methods that are set forth in the fabric characterization publications. Note that the indications of "N/C" in Figures 3A-3F mean that the particular characteristics were not determined.

[0034] The air permeability of a structuring fabric is another characteristic that can influence the properties of paper products made with the structuring fabric. The air permeability of a structuring fabric is measured according to well-known equipment and tests in the art, such as Frazier® Differential Pressure Air Permeability Measuring Instruments by Frazier Precision Instrument Company of Hagerstown, Maryland. Generally speaking, the long warp knuckle structuring fabrics used to produce paper products according to our invention have a high amount of air permeability. In a particular embodiment of our invention, the long warp knuckle structuring fabric has an air permeability of about 450 CFM to about 1000 CFM.

[0035] Figures 4A-4E are photographs of absorbent sheets made with long warp knuckle structuring fabrics, such as those characterized in Figures 3A-3E. More specifically, Figures 4A-4E show the air side of the absorbent sheets, that is, the side of the absorbent sheets that contacted the structuring fabric during the process of forming the absorbent sheets. Thus, the distinct shapes that are imparted to the absorbent sheets through contact with the structuring fabrics, including domed regions projecting from the shown side of the absorbent sheet, can be seen in Figures 4A-4E. Note that the MD of the absorbent sheets is shown vertically in these figures.

[0036] Specific features of the absorbent sheet 1000 are annotated in Figure 5, which is the photograph shown as Figure 4E. The absorbent sheet 1000 includes a plurality of substantially rectangular-shaped domed regions, some of which are outlined and labeled 1010, 1020, 1030, 1040, 1050, 1060, 1070, and 1080 in Figure 5. As explained above, the domed regions 1010, 1020, 1030, 1040, 1050, 1060, 1070, and 1080 correspond to the portions of the web that were drawn into the pockets of the structuring fabric during the process of forming the absorbent sheet 1000. Connecting regions, some of which are labeled 1015, 1025, and 1035 in Figure 5, form a network interconnecting the domed regions. The connecting regions generally correspond to portions of the web that were formed in the plane of the knuckles of the structuring fabric during the process of forming the absorbent sheet 1000.

[0037] Those skilled in the art will immediately recognize several features of the absorbent sheets shown in Figures 4A-4E and 5 that are different than conventional absorbent sheets. For instance, all of the domed regions include a plurality of indented bars formed into the tops of the domed regions, with the indented bars extending across the domed regions in the CD of the absorbent sheets. Some of these indented bars are outlined and labeled 1085 in Figure 5. Notably, almost all of the domed regions have three such indented bars, with some of the domed regions having four, five, six, seven, or even eight indented bars. The number of indented bars can be confirmed using laser scan profiling (described below). Using such laser scan profiling, it was found that in a particular absorbent sheet according to an embodiment of our invention, there are, on average (mean), about six indented bars per domed region.

[0038] Without being limited by theory, we believe that the indented bars seen in the absorbent sheets shown in Figure 4A-4E and 5 are formed when the web is transferred onto a structuring fabric with the configurations described herein during a papermaking process as described herein. Specifically, when a speed differential is used for creping the web as it is transferred onto the structuring fabric, the web "plows" onto the knuckles of the structuring fabric and into the pockets between the knuckles. As a result, folds are created in the structure of the web, particularly in the areas of the web that are moved into the pockets of the structuring fabric. An indented bar is thus formed between two of such folds in the web. Because of the long MD pockets in the long warp yarn knuckle structuring fabrics described herein, the plowing/folding effect takes place multiple times over a portion of a web that spans a pocket in the structuring fabric. Thus, multiple indented bars are formed in each of the domed regions of absorbent sheets made with the long warp knuckle structuring fabrics described herein.

[0039] Again, without being limited by theory, we believe that the indented bars in the domed regions may contribute to an increased softness that is perceived in the absorbent sheets according to our invention. Specifically, the indented bars provide a more smooth, flat plane being perceived when the absorbent sheet is touched, as compared to absorbent sheets having conventional domed regions. The difference in perceptional planes is illustrated in Figures 6A and 6B, which are drawings showing cross sections of an absorbent sheet 2000 according to our invention and a comparison sheet 3000, respectively. In absorbent sheet 2000, the domed regions 2010 and 2020 include indented bars 2080, with ridges being formed between the indented bars 2080 (the ridges/indents correspond to the folds in the web during the papermaking process as described above). As a result of the small indented bars 2080 and plurality of ridges around the indented bars 2080, flat, smooth perceived planes P1 (marked with dotted lines in Figure 6A) are formed. These flat, smooth planes P1 are sensed when the absorbent sheet 2000 is touched. We further believe that the users cannot detect the small discontinuities of the indented bars 2080 in the surfaces of the domed regions 2010 and 2020, nor can users detect the short distance between the domed regions 2010 and 2020. Thus, the absorbent sheet 2000 is perceived as having a smooth, soft surface. On the other hand, the perceived planes P2 have a more rounded shape with the conventional domes 3010 and 3020 in comparison sheet 3000, as shown in Figure 6B, and the conventional domes 3010 and 3020 are spaced apart. It is believed that because the perceived planes P2 of the conventional domes 3010 and 3020 are spaced a significant distance from each other, the comparison sheet 3000 is perceived as less smooth and soft compared to the perceived planes P1 found in the domed regions 2010 and 2020 with the indented bars 2080.

[0040] Those skilled in the art will appreciate that, due to the nature of a papermaking process, not every domed region in an absorbent sheet will be identical. Indeed, as noted above, domed regions of an absorbent sheet according to our invention might have different numbers of indented bars. At the same time, a few of the domed regions observed in any particular absorbent sheet of our invention might not include any indented bars. This will not affect the overall properties of the absorbent sheet, however, as long as a majority of the domed regions includes the indented bars. Thus, when we refer to an absorbent sheet as having domed regions that include a plurality of indented bars, it will be understood that that absorbent sheet might have a few domed regions with no indented bars.

[0041] The lengths and depths of the indented bars in absorbent sheets, as well as the lengths of the domed regions, can be determined from a surface profile of a domed region that is made using laser scanning techniques, which are well known in the art. Figures 7A and 7B show laser scans profiles across domed regions in two absorbent sheets according to our invention. The peaks of the laser scan profiles are the areas of the domes that are adjacent to the indented bars, while the valleys of the profiles represent the bottoms of the indented bars. Using such laser scan profiles, we have found that the indented bars extend to a depth of about 45 microns to about 160 microns below the tops of the adjacent areas of the domed regions. In a particular embodiment, the indented bars extend an average (mean) of about 90 microns below the tops of the adjacent areas of the domed regions. In some embodiments, the domed regions extend a total of about 2.5 mm to about 3 mm in length in a substantially MD of the absorbent sheets. Those skilled in the art will appreciate that such lengths in the MD of the domed regions are greater than the lengths of domed regions in conventional fabrics, and that the long domed regions are at least partially the result of the long MD pockets in the structuring fabrics used to create the absorbent sheets, as discussed above. From the laser scan profiles, it can also be seen that the indented bars were spaced about 0.5 mm apart along the lengths of the domed regions in embodiments of our invention.

[0042] Further distinct features that can be seen in the absorbent sheets shown in Figures 4A-4E and 5 include the dome regions being bilaterally staggered in the MD such that substantially continuous, stepped lines of domed regions extend in the MD of the sheets. For example, with reference again to Figure 5, the domed region 1010 is positioned adjacent to the domed region 1020, with the two domed regions overlapping in a region 1090. Similarly, the domed region 1020 overlaps domed region 1030 in a region 1095. The bilaterally staggered domed regions 1010, 1020, and 1030 form a continuous, stepped line, substantially along the MD of the absorbent sheet 1000. Other domed regions form similar continuous, stepped lines in the MD.

[0043] We believe that the configuration of the elongated, bilaterally staggered domed regions, in combination with the indented bars extending across the domed regions, results in the absorbent sheets having a more stable configuration. For example, the bilaterally staggered domed regions provides for a smooth planar surface on the Yankee side of the absorbent sheets, which thereby results in a better distribution of pressure points on the absorbent sheet (the Yankee side of an absorbent sheet being the side of the absorbent sheets that is opposite to the air side of the absorbent sheets that is drawn into the structuring fabric during the papermaking process). In effect, the bilaterally staggered domed regions act like long boards in the MD direction that cause the absorbent sheet structure to lay flat. This effect, resulting from the combination of bilaterally staggered domed regions and indented bars will, for example, cause a web to better lay down on the surface of a Yankee dryer during a papermaking process, which results in better absorbent sheets.

[0044] Similar to the continuous lines of domed regions, substantially continuous lines of connecting regions extend in a stepped manner along the MD of the absorbent sheet 1000. For example, connection region 1015, which runs substantially in the CD, is contiguous with connecting region 1025, which runs substantially in the CD. Connecting region 1025 is also contiguous with connecting region 1035, which runs substantially in the MD. Similarly, connecting region 1015 is contiguous with connecting region 1025 and connecting region 1055. In sum, the MD connecting regions are substantially longer than the CD connecting regions, such that lines of stepped, continuous connecting regions can be seen along the absorbent sheet.

[0045] As discussed above, the sizes of the domed regions and the connecting regions of an absorbent sheet generally correspond to the pocket and knuckle sizes in the structuring fabric used to produce the absorbent sheet. In this regard, we believe that the relative sizing of the domed and connecting regions contributes to the softness of absorbent sheets made with the fabric. We also believe that the softness is further improved as a result of the substantially continuous lines of domed regions and connecting regions. In a particular embodiment of our invention, a distance in the CD across the domed regions is about 1.0 mm, and a distance in the CD across the MD oriented connecting regions is about 0.5 mm. Further, the overlap/touching regions between adjacent domed regions in the substantially continuous lines are about 1.0 mm in length along the MD. Such dimensions can be determined from a visual inspection of the absorbent sheets, or from a laser scan profile as described above. An exceptionally soft absorbent sheet can be achieved when these dimensions are combined with the other features of our invention described herein.

[0046] In order to evaluate the properties of products according to our invention, absorbent sheets were made using Fabric 15 as shown Figure 3E in a papermaking machine having the general configuration shown in Figure 1 with a process as described above. For comparison, products were made using the shorter warp length knuckle Fabric 17 that is also shown in Figure 3F under the same process conditions. Parameters used to produce basesheets for these trials are shown in TABLE 1.
TABLE 1
Process VariableLocationRate
Furnish: 100 % SHWK to Yankee layer Stratified
65% SHWK  
35% SSWK 70% SSWK and 30% SHWKK to middle and air layers
Refiner Stock Vary as needed
Temporary Wet Strength Resin: FJ98 Stock pumps 3 lb/T
Starch: REDIBOND™ 5330A Static mixers 8 lb/T
Crepe Roll Load Crepe Roll 45 PLI
Fabric Crepe Crepe Roll 20%
Reel Crepe Reel 7%
Calender Load Calender Stacks As needed
Molding Box Vacuum Molding Box Maximum


[0047] The basesheets were converted to produce two-ply glued tissue prototypes. TABLE 2 shows the converting specifications for the trials.
TABLE 2
Conversion ProcessGluing
Number of Plies 2
Roll Diameter 4.65 in.
Sheet Count 190
Sheet Length 4.09 in.
Sheet Width 4.05 in.
Roll Compression 18-20%
Emboss Process Following process of U.S. Patent No. 6,827,819 (which is incorporated by reference in its entirety)
Emboss Pattern Constant/Non-Varying


[0048] Sheets formed in the trials with Fabric 15 (i.e., a long warp knuckle fabric) were found to be smoother and softer than the sheets formed in the trials with Fabric 17 (i.e., a shorter warp knuckle fabric). Other important properties of the sheets made with Fabric 15, such as caliper and bulk, were found to be very comparable to those properties of the sheets made with Fabric 17. Thus, it is clear that the basesheets made with the long warp knuckle Fabric 15 could potentially be used to make absorbent products that are softer than absorbent products with the shorter warp knuckle Fabric 17 without the reduction of other important properties of the absorbent products.

[0049] As described in the aforementioned fabric characterization patents, the planar volumetric index (PVI) is a useful parameter for characterizing a structuring fabric. The PVI for a structuring fabric is calculated as the contact area ratio (CAR) multiplied by the effective pocket volume (EPV) multiplied by one hundred, where the EPV is the product of the pocket area estimate (PA) and the measured pocket depth. The pocket depth is most accurately calculated by measuring the caliper of a handsheet formed on the structuring fabric in a laboratory, and then correlating the measured caliper to the pocket depth. And, unless otherwise noted, all of the PVI-related parameters described herein were determined using this handsheet caliper measuring method. Further, a non-rectangular, parallelogram PVI is calculated as the contact area ratio (CAR) multiplied by the effective pocket volume (EPV) multiplied by one hundred, where the CAR and EPV are calculated using a non-rectangular, parallelogram unit cell area calculation. In embodiments of our invention, the contact area of the structuring long warp knuckle fabric varies between about 25% to about 35% and the pocket depth varies between about 100 microns to about 600 microns, with the PVI thereby varying accordingly.

[0050] Another useful parameter for characterizing a structuring fabric related to the PVI is a planar volumetric density index (PVDI) of the structuring fabric. The PVDI of a structuring fabric is defined as the PVI multiplied by pocket density. Note that in embodiments of our invention, the pocket density varies between about 10 cm-2 to about 47 cm-2. Yet another useful parameter of a structuring fabric can be developed by multiplying the PVDI by the ratio of the length and width of the knuckles of the fabric, thereby providing a PVDI-knuckle ratio (PVDI-KR). For example, a PVDI-KR for a long warp knuckle structuring fabric as described herein would be the PVDI of the structuring fabric multiplied by the ratio of warp knuckles length in the MD to the warp knuckles width in the CD. As is apparent from the variables used to calculate the PVDI and PVDI-KR, these parameters take into account important aspects of a structuring fabric (including percentage of contact area, pocket density, and pocket depth) that affect shapes of paper products made using the structuring fabric, and, hence, the PVDI and PVDI-KR may be indicative of the properties of the paper products such as softness and absorbency.

[0051] The PVI, PVDI, PVDI-KR, and other characteristics were determined for three long warp knuckle structuring fabrics according to embodiments of our invention, with the results being shown as Fabrics 18-20 in Figure 8. For comparison, the PVI, PVDI, PVDI-KR, and other characteristics were also determined for a shorter warp knuckle structuring fabric, as is shown as Fabric 21 in Figure 8. Notably, the PVDI-KRs for Fabrics 18-20 are about 43 to about 50, which are significantly greater than the PVDI-KR of 16.7 for Fabric 21.

[0052] Fabrics 18-21 were used to produce absorbent sheets, and characteristics of the absorbent sheets were determined, as shown in Figure 9. The characteristics shown in Figure 9 were determined using the same techniques that are described in the aforementioned fabric characterization patents. In this regard, the determinations of the interconnecting regions correspond to the warp knuckles on the structuring fabric, and the dome regions correspond to the pockets of the structuring fabric. Also, it could again be seen that the sheets made from the long warp knuckle Fabrics 18-20 have multiple indented bars in each dome region. On the other hand, the domed regions of the absorbent sheet formed from the shorter warp knuckle Fabric 21 had, at most, one indented bar, and many of the domed regions did not have any indented bars at all.

[0053] The sensory softness was determined for the absorbent sheets shown in Figure 9. Sensory softness is a measure of the perceived softness of a paper product as determined by trained evaluators using standardized testing techniques. More specifically, sensory softness is measured by evaluators experienced with determining the softness, with the evaluators following specific techniques for grasping the paper and ascertaining a perceived softness of the paper. The higher the sensory softness number, the higher the perceived softness. In the case of the sheets made from Fabrics 18-20, it was found that the absorbent sheets made with Fabrics 18-20 were 0.2 to 0.3 softness units higher than the absorbent sheets made with Fabric 21. This difference is outstanding. Moreover, the sensory softness was found to correlate with the PVDI-KR of the fabrics. That is, the higher the PVDI-KR of the structuring fabric, the higher the sensory softness number that was achieved. Thus, we believe that PVDI-KR is a good indicator of the softness that can be achieved in a paper product made with a process using a structuring fabric, with a higher PVDI-KR structuring fabric producing a softer product.

[0054] Figures 10A through 10D show characteristics of further long-warp knuckle Fabrics 22-41 according to various embodiments of our invention, including the PVI, PVDI, and PVDI-KR for each of the fabrics. Notably, these structuring fabrics have a wider range of characteristics than the structuring fabrics described above. For example, contact lengths of the warp knuckles of Fabrics 22-41 ranged from about 2.2 mm to about 5.6 mm. In further embodiments of our invention, however, the contact lengths of the warp knuckles may range from about 2.2 mm to about 7.5 mm. Note that in the case of Fabrics 22-37 and 41, the pocket depths were determined by forming a handsheet on the fabrics and then determining the size of domes on the handsheet (the size of the domes corresponding to the size of the pockets, as described above). The pocket depths for Fabrics 38-40 were determined using techniques set forth in the aforementioned fabric characterization patents.

[0055] Further trials were conducted to evaluate properties of absorbent sheets according to embodiments of our invention. In these trials, the Fabrics 27 and 38 were used. For these trials, a papermaking machine having the general configuration shown in Figure 1 was used with a process as described above. Parameters used to produce the basesheets for these trials are shown in TABLE 3. Note that an indication of a varying rate means that the process variable was varied in different trial runs.
TABLE 3
Process VariableLocationRate
Furnish Lighthouse Recycled Fibers Homogeneous
Refiner Stock No load (22 hp)
Temporary Wet Strength Resin N/A 0
Starch: REDIBOND™ 5330A Static mixers As needed
Crepe Roll Load Crepe Roll 30-40 PLI
Fabric Crepe Crepe Roll varying 25%-35%
Reel Crepe Reel 2-4%
Molding Box Vacuum Molding Box Maximum


[0056] The basesheets in these trials were converted into unembossed, single-ply rolls.

[0057] Pictures of the absorbent sheets made with Fabric 27 are shown in Figures 11A-11E and pictures of the absorbent sheets made with Fabric 38 are shown in Figures 12A-12E. As is apparent from Figures 11A-11E and 12A-12E, the domed regions of the absorbent sheets included a plurality of indented bars like the absorbent sheets described above. And, also like the absorbent sheets described above, the absorbent sheets made with Fabrics 27 and 38 include bilaterally staggered domed regions that result in substantially continuous, stepped lines in the MD of the absorbent sheets, and substantially continuous, stepped connecting regions between the domed regions.

[0058] The profiles of the domed regions in the basesheets made from Fabrics 27 and 38 were determined using laser scanning, in the same manner that the profiles were determined in the absorbent sheets described above. It was found that the domed regions in the basesheets made with Fabric 27 had 4 to 7 indented bars, with there being an average (mean) of 5.2 indented bars per domed region. The indented bars of domed regions extended from about 132 to about 274 microns below the tops of adjacent areas of the domed regions, with an average (mean) depth of about 190 microns. Further, the domed regions extended about 4.5 mm in the MD of the basesheets.

[0059] The domed regions in the basesheets made with Fabric 38 had 4 to 8 indented bars, with there being an average (mean) of 6.29 indented bars per domed region. The indented bars of domed regions in the basesheets made with Fabric 38 extended from about 46 to about 159 microns below the tops of adjacent areas of the domed regions, with an average (mean) depth of about 88 microns. Further, the domed regions extended about 3 mm in the MD of the basesheets.

[0060] Because the extended MD direction domed regions in the basesheets made with Fabrics 27 and 38 include a plurality of indented bars, it follows that the basesheets will have similar beneficial properties stemming from the configuration of the domed regions as the absorbent sheets described above. For example, the basesheets made with Fabrics 27 and 38 will be softer to the touch compared to basesheets made with fabrics not having long warp knuckles.

[0061] Other properties of the basesheets made with Fabrics 27 and 38 were compared to the properties of basesheets made with shorter knuckle fabrics. Specifically, the caliper and pocket depth were compared for uncalendered basesheets made with the different fabrics. The caliper was measured using standard techniques that are well known in the art. It was found that the caliper of the basesheets made with Fabric 27 varied from about 80 mils/8 sheets to about 110 mils/8 sheets, while the basesheets made with Fabric 38 varied from about 80 mils/8 sheets to about 90 mils/8 sheets. Both of these ranges of caliper are very comparable, if not better than, the about 60 to about 93 mils/8 sheets caliper that was found in the basesheets made with shorter warp yarn knuckle fabrics under similar process conditions.

[0062] The depths of the domed regions were measured using a topographical profile scan of the air side (i.e, the side of the basesheets that contacts the structuring fabric during the papermaking process) of the basesheets to determine the depths of the lowest points of domed regions below the Yankee side surface. The depths of the domed regions in the basesheets made using Fabric 27 ranged from about 500 microns to about 675 microns, while the depths of the domed regions in the basesheets made using Fabric 38 ranged from about 400 microns to about 475 microns. These domed regions were comparable to, if not greater than, the depths of the domed regions in basesheets made from the structuring fabrics having shorter warp yarn knuckles. This comparability of the depths of domed regions is consistent with the finding that the basesheets made with the long warp yarn structuring fabrics having comparable caliper to the basesheets made with the shorter warp yarn structuring fabrics inasmuch as the depth of domed regions is directly related to the caliper of an absorbent sheet.

[0063] The characteristics of further long warp yarn knuckle fabrics according to our invention are labeled as Fabrics 42-44 in Figure 13. Also shown in Figure 13 is a conventional Fabric 45 that does not include long warp yarn knuckles. Further characteristics of Fabric 42 are given in Figure 14, which shows the profile along one of the warp yarns of the fabric. As can be seen in these figures, Fabric 42 has several notable features in addition to including long warp yarn knuckles. One feature is that the pockets are long and deep, as reflected in the PVI related parameters indicated in Figure 13. As can also be seen in the pressure imprint of Fabric 42 shown in Figure 13, another notable feature of this fabric is that the CD yarns are entirely located below the plane of the knuckles in the MD yarns such that there are no CD knuckles at the top surface of the fabric. Because there are no CD knuckles, there is a gradual slope to the warp yarns in the z-direction, the details of which are shown in the profile scan in Figure 14. As indicated in this figure, the warp yarns have a slope of about 200 µm/mm from the lowest point where the warp yarns pass under a CD yarn to the top of the adjacent warp knuckle. More generally speaking, the warp yarns are angled from about 11 degrees relative to a plane that Fabric moves along during the creping operation. It is believed that this gradual slope of the warp yarns allows the fibers in a web being pressed to Fabric 42 to only slightly pile up on the sloped portion of the warp yarn before being some of the fibers slip up over the top of the adjacent knuckle. The gradual slope of the warp yarns in Fabric 42 thereby creates less of an abrupt stop for the fibers of the web and less densification of the fibers compared to other fabrics where the warp yarns have a steeper slope that is contacted by the web.

[0064] Fabrics 42 and 43 both have higher PVDI-KR values, and these values in conjunction with the PVDI-KR values of the other structuring fabrics described herein are generally indicative of the range of PVDI-KR values that can be found in embodiments of our invention. Further, structuring fabrics with even higher PVDI-KR values could also be used, for example, up to about 250.

[0065] In order to evaluate the properties of Fabric 42, a series of trials was conducted with this fabric and with Fabric 45 for comparison. In these trials, a papermaking machine having the general configuration shown in Figure 1 was used to form absorbent towel basesheets. The non-TAD process described generally above and specifically set forth in the aforementioned '563 patent was used, wherein the web was dewatered to the point that it had a consistency of about 40 to about 43 percent when transferred onto the top side of the structuring fabric (i.e., Fabric 42 or 45) at the creping nip. Other particular parameters of these trails were as shown in TABLE 4.
TABLE 4
Process VariableLocationRate
Furnish Premium ("P"): 70 % NSWK/ 30% Eucalyptus. or Non-premium ("NP"): 70 % SSWK/ 30% SHWK Stratified
Refiner Stock Varies
WSR/CMC (#/T total) Static Mixer 20/3.2
Debonder Addition None None
Crepe Roll Load Crepe Roll 40-60 PLI
Fabric Crepe Crepe Roll As indicated in tables below
Reel Crepe Reel 2%
Molding Box Vacuum Molding Box Varying between full and zero


[0066] The properties of the basesheets made in these trials with Fabrics 42 and 45 are shown in TABLES 5-9. The testing protocols used to determine the properties indicated in TABLES 5-9 can be found in U.S. Patent Nos. 7,399,378 and 8,409,404, which are incorporated herein by reference in their entirety. An indication of "N/C" indicates that a property was not calculated for a particular trial.
TABLE 5
Trial1234567891011
Fabric 45 45 45 45 45 45 45 45 45 45 45
Fabric Crepe (%) 3 3 5 5 8 8 15 15 20 20 30
Furnish NP NP NP NP NP NP NP NP NP NP NP
Caliper (mils/8 sheets) 63.18 62.93 68.20 67.35 77.98 77.53 84.98 88.43 92.38 90.55 99.38
Basis Weight (lb/3000 ft2) 15.17 15.42 15.33 15.38 15.31 15.34 15.59 15.28 15.85 15.50 15.47
MD Tensile (g/3 in) 1590 1554 1353 1639 1573 1498 1387 1445 1401 1145 1119
MD Stretch (%) 8.1 8.9 9.8 10.3 13.1 12.4 20.1 18.8 24.2 24.5 33.9
CD Tensile (g/3 in) 1393 1382 1294 1420 1393 1428 1401 1347 1231 1200 1272
CD Stretch (%) 4.5 4.8 4.5 4.7 4.9 4.9 6.1 7.1 6.1 6.0 7.0
Wet Tensile Finch Cured-CD (g/3 in) 378.42 377.31 396.72 426.79 392.27 399.08 389.35 359.39 381.15 383.22 388.66
SAT Capacity (g/m2) 303.76 316.09 329.09 339.94 369.38 362.64 421.02 415.43 454.08 420.03 486.14
GM Tensile (g/3 in) 1488 1466 1323 1526 1481 1462 1394 1395 1313 1172 1193
GM Break Modulus (g/%) 254.08 227.72 198.96 220.16 186.53 189.30 130.30 116.76 108.50 97.10 78.67
SAT Time (s) N/C N/C N/C N/C 47.3 47.3 N/C N/C N/C N/C N/C
Tensile Dry Ratio 1.14 1.12 1.05 1.15 1.13 1.05 0.99 1.07 1.14 0.95 0.88
SAT Rate g/s0.5 N/C N/C N/C N/C 0.1233 0.1073 N/C N/C N/C N/C N/C
Tensile Total Dry (g/3 in) 2983 2937 2647 3059 2967 2926 2788 2792 2632 2345 2391
Tensile Wet/Dry CD 0.27 0.27 0.31 0.30 0.28 0.28 0.28 0.27 0.31 0.32 0.31
Basis Weight Raw Wt (g) 1.147 1.166 1.159 1.163 1.158 1.160 1.179 1.156 1.198 1.172 1.170
T.E.A. CD (mm-g/mm2) 0.386 0.388 0.370 0.439 0.448 0.434 0.505 0.537 0.472 0.445 0.521
T.E.A. MD (mm-g/mm2) 0.693 0.759 0.733 0.911 1.043 0.982 1.461 1.400 1.700 1.431 1.993
CD Break Modulus (g/%) 314.12 292.46 274.57 305.26 283.37 297.78 240.35 171.68 200.07 199.94 190.52
MD Break Modulus (g/%) 205.51 177.30 144.18 158.79 122.78 120.33 70.64 79.40 58.84 47.16 32.48
TABLE 6
Trial1213141516171819202122
Fabric 45 45 42 42 42 42 42 42 42 42 42
Fabric Crepe (%) 30 40 5 5 8 8 12 12 15 15 17.5
Furnish NP NP NP NP NP NP NP NP NP NP NP
Caliper (mils/8 sheets) 100.03 103.35 104.73 101.30 103.33 106.95 112.40 111.78 115.83 124.73 118.75
Basis Weight (lb/3000 ft2) 15.48 15.89 15.55 15.71 15.16 15.77 15.52 14.99 15.62 15.46 15.54
MD Tensile (g/3 in) 1191 1310 1346 1404 1217 1381 1205 1118 1139 1193 1100
MD Stretch (%) 33.8 42.1 9.4 9.2 11.9 13.6 16.3 16.8 18.5 18.6 22.5
CD Tensile (g/3 in) 1216 1091 1221 1171 1164 1305 1229 1187 1208 1273 1186
CD Stretch (%) 6.4 9.7 6.7 6.5 7.6 6.7 8.2 9.0 8.9 7.3 8.4
Wet Tensile Finch Cured-CD (g/3 in) 375.14 333.25 384.19 341.28 334.01 391.05 383.33 356.94 367.40 386.18 398.40
SAT Capacity (g/m2) 482.86 N/C 421.51 426.61 457.53 455.88 479.24 509.33 533.67 491.24 515.91
GM Tensile (g/3 in) 1203 1195 1282 1283 1191 1343 1217 1152 1173 1232 1142
GM Break Modulus (g/%) 84.14 59.92 162.90 168.66 128.36 141.14 105.49 93.56 94.07 106.55 84.05
SAT Time (s) N/C N/C 58.5 55.9 48.4 62.4 46.9 46.6 43.8 39.6 40.8
Tensile Dry Ratio 0.98 1.20 1.10 1.20 1.05 1.06 0.98 0.94 0.94 0.94 0.93
SAT Rate g/s0.5 N/C N/C 0.1240 0.1250 0.1460 0.1330 0.1463 0.1703 0.1787 0.1653 0.1747
Tensile Total Dry (g/3 in) 2406 2401 2568 2576 2382 2686 2434 2305 2347 2466 2286
Tensile Wet/Dry CD 0.31 0.31 0.31 0.29 0.29 0.30 0.31 0.30 0.30 0.30 0.34
Basis Weight Raw Wt (g) 1.170 1.202 1.176 1.188 1.146 1.193 1.173 1.134 1.181 1.169 1.175
T.E.A. CD (mm-g/mm2) 0.493 0.614 0.486 0.458 0.504 0.520 0.561 0.586 0.600 0.527 0.555
T.E.A. MD (mm-g/mm2) 2.102 2.729 0.854 0.875 0.965 1.147 1.262 1.191 1.326 1.397 1.476
CD Break Modulus (g/%) 200.28 115.03 186.61 185.12 160.98 196.28 149.84 131.23 142.85 172.21 141.16
MD Break Modulus (g/%) 35.35 31.21 142.20 153.67 102.35 101.49 74.26 66.71 61.95 65.93 50.04
TABLE 7
Trial2324252627282930313233
Fabric 42 42 42 42 42 42 42 42 42 42 42
Fabric Crepe (%) 17.5 20 20 25 25 3 3 5 5 8 8
Furnish NP NP NP NP NP P P P P P P
Caliper (mils/8 sheets) 120.55 125.73 119.30 119.08 117.58 88.60 80.00 102.35 99.75 106.93 113.50
Basis Weight (lb/3000 ft2) 15.36 15.46 15.54 15.71 15.56 15.38 15.73 15.46 15.67 15.73 15.59
MD Tensile (g/3 in) 1156 1168 1218 1098 1164 1545 1481 1255 1336 1305 1266
MD Stretch (%) 22.7 24.9 24.5 28.8 29.6 8.6 8.3 11.5 11.5 13.5 13.4
CD Tensile (g/3 in) 1230 1137 1220 1135 1160 1353 1263 1171 1194 1202 1145
CD Stretch (%) 9.5 9.8 10.1 9.0 8.7 6.6 6.6 7.4 7.7 7.1 8.4
Wet Tensile Finch Cured-CD (g/3 in) 389.77 355.26 412.54 353.38 358.26 394.94 400.23 365.83 380.93 404.07 342.44
SAT Capacity (g/m2) 549.13 566.40 487.13 550.61 541.90 366.91 380.56 438.45 424.80 462.79 454.57
GM Tensile (g/3 in) 1192 1152 1219 1116 1162 1446 1368 1212 1263 1252 1204
GM Break Modulus (g/%) 79.01 75.16 77.59 69.14 71.02 189.84 187.19 134.80 135.76 127.34 114.64
SAT Time (s) 46.2 82.5 61.1 49.6 46.0 59.8 61.4 60.9 61.3 63.5 58.6
Tensile Dry Ratio 0.94 1.03 1.00 0.97 1.00 1.14 1.17 1.07 1.12 1.09 1.11
SAT Rate g/s0.5 0.1747 0.1410 0.1297 0.1593 0.1613 0.0753 0.0917 0.1230 0.1123 0.1313 0.1263
Tensile Total Dry (g/3 in) 2386 2305 2438 2233 2324 2898 2744 2426 2530 2506 2411
Tensile Wet/Dry CD 0.32 0.31 0.34 0.31 0.31 0.29 0.32 0.31 0.32 0.34 0.30
Basis Weight Raw Wt (g) 1.162 1.169 1.175 1.188 1.176 1.163 1.189 1.169 1.185 1.190 1.179
T.E.A. CD (mm-g/mm2) 0.638 0.647 0.652 0.610 0.613 0.503 0.492 0.505 0.533 0.501 0.514
T.E.A. MD (mm-g/mm2) 1.520 1.661 1.710 1.849 1.965 0.843 0.784 0.924 0.965 1.090 1.054
CD Break Modulus (g/%) 121.69 118.88 118.90 125.56 129.39 202.35 193.60 160.78 156.90 165.68 136.75
MD Break Modulus (g/%) 51.31 47.52 50.63 38.07 38.99 178.10 181.00 113.03 117.47 97.87 96.10
TABLE 8
Trial34353637383940414243
Fabric 42 42 42 42 42 42 42 42 42 42
Fabric Crepe (%) 12 12 15 15 17.5 17.5 20 20 25 25
Furnish P P P P P P P P P P
Caliper (mils/8 sheets) 106.90 111.85 126.78 113.55 116.38 117.43 124.28 118.38 127.15 123.45
Basis Weight (lb/3000 ft2) 15.25 15.52 15.28 15.56 15.22 15.13 15.27 15.36 15.73 15.66
MD Tensile (g/3 in) 1285 1362 1151 1099 1163 1246 1311 1268 1126 1114
MD Stretch (%) 18.0 17.8 21.4 20.1 24.2 21.7 24.1 25.6 30.0 29.5
CD Tensile (g/3 in) 1263 1291 1105 1239 1309 1156 1279 1188 1153 1215
CD Stretch (%) 8.9 8.2 9.8 8.9 9.8 10.1 10.4 10.4 11.3 10.8
Wet Tensile Finch Cured-CD (g/3 in) 361.36 377.41 363.51 382.17 382.19 340.60 364.82 370.56 380.50 371.50
SAT Capacity (g/m2) 540.09 498.97 502.43 514.43 535.48 558.67 585.81 568.05 553.90 551.76
GM Tensile (g/3 in) 1274 1326 1128 1167 1234 1200 1295 1227 1139 1163
GM Break Modulus (g/%) 101.68 109.99 78.18 87.01 80.40 82.55 84.45 76.02 62.29 64.93
SAT Time (s) 37.5 42.7 55.4 47.3 50.2 51.4 45.1 44.3 66.6 53.5
Tensile Dry Ratio 1.02 1.06 1.04 0.89 0.89 1.08 1.03 1.07 0.98 0.92
SAT Rate g/s0.5 0.1637 0.1557 0.1480 0.1570 0.1623 0.1553 0.1753 0.1783 0.1453 0.1483
Tensile Total Dry (g/3 in) 2548 2652 2257 2338 2472 2402 2589 2456 2279 2328
Tensile Wet/Dry CD 0.29 0.29 0.33 0.31 0.29 0.29 0.29 0.31 0.33 0.31
Basis Weight Raw Wt (g) 1.153 1.173 1.156 1.177 1.151 1.144 1.155 1.161 1.189 1.184
T.E.A. CD (mm-g/mm2) 0.627 0.625 0.566 0.600 0.676 0.617 0.695 0.659 0.691 0.703
T.E.A. MD (mm-g/mm2) 1.393 1.474 1.421 1.371 1.592 1.599 1.825 1.803 1.928 1.907
CD Break Modulus (g/%) 145.26 158.25 111.51 137.62 134.41 116.31 128.13 116.00 101.44 113.29
MD Break Modulus (g/%) 71.18 76.45 54.81 55.01 48.09 58.59 55.66 49.82 38.25 37.21
TABLE 9
Trial44454647
Fabric 42 42 42 42
Fabric Crepe (%) 30 30 35 35
Furnish P P P P
Caliper (mils/8 sheets) 126.38 124.25 122.83 123.23
Basis Weight (lb/3000 ft2) 15.75 15.47 15.35 14.46
MD Tensile (g/3 in) 1126 1118 1157 1097
MD Stretch (%) 35.0 35.2 33.9 34.4
CD Tensile (g/3 in) 1050 1090 1083 1097
CD Stretch (%) 11.2 10.2 10.6 10.8
Wet Tensile Finch Cured-CD (g/3 in) 366.41 398.97 363.35 377.73
SAT Capacity (g/m2) 549.30 522.16 544.69 533.02
GM Tensile (g/3 in) 1088 1104 1119 1097
GM Break Modulus (g/%) 54.29 56.95 59.34 56.65
SAT Time (s) 51.3 66.1 58.4 53.2
Tensile Dry Ratio 1.07 1.03 1.07 1.00
SAT Rate g/s0.5 0.1457 0.1330 0.1543 0.1547
Tensile Total Dry (g/3 in) 2176 2208 2240 2194
Tensile Wet/Dry CD 0.35 0.37 0.34 0.34
Basis Weight Raw Wt (g) 1.191 1.170 1.161 1.093
T.E.A. CD (mm-g/mm2) 0.625 0.628 0.639 0.623
T.E.A. MD (mm-g/mm2) 2.094 2.062 2.049 2.074
CD Break Modulus (g/%) 90.54 103.85 103.20 100.59
MD Break Modulus (g/%) 32.55 31.23 34.12 31.90


[0067] The results of the trials shown in TABLES 5-9 demonstrate that Fabric 42 can be used to produce basesheets having an outstanding combination of properties, particularly caliper and absorbency. Without being bound by theory, we believe that these results stem, in part, from the configuration of knuckles and pockets in Fabric 42. Specifically, the configuration of Fabric 42 provides for a highly efficient creping operation due to the aspect ratio of the pockets (i.e., the length of the pockets in the MD versus the width of the pockets in the CD), the pockets being deep, and the pockets being formed in long, near continuous lines in the MD. These properties of the pockets allow for great fiber "mobility," which is a condition where the wet compressed web is subjected to mechanical forces that create localized basis weight movement. Moreover, during the creping process, the cellulose fibers in the web are subjected to various localized forces (e.g., pushed, pulled, bent, delaminated), and subsequently become more separated from each other. In other words, the fibers become de-bonded and result in a lower modulus for the product. The web therefore has better vacuum "moldability," which leads to greater caliper and a more open structure that provides for greater absorption.

[0068] The fiber mobility provided for with the pocket configuration of Fabric 42 can be seen in the results shown in Figures 15 and 16. These figures compare the caliper, SAT capacity, and void volume at the various crepe levels used in the trials. Figures 15 and 16 show that, even in the trials with Fabric 42 where no vacuum molding was used, the caliper and SAT capacity increased with the increasing fabric crepe level. As there was no vacuum molding, it follows that these increases in caliper and SAT capacity are directly related to fiber mobility in Fabric 42. Figures 15 and 16 also demonstrate that a high amount of caliper and SAT capacity are achieved using Fabric 42-in the trials where vacuum molding is used, at each creping level the caliper and SAT capacity of the basesheets made with Fabric 42 were much greater than the caliper and SAT capacity of the basesheets made with Fabric 45.

[0069] The fiber moldability provided by Fabric 42 can also be seen in the results shown in Figure 15 and 16. Specifically, the differences between the caliper and SAT capacity in the trials with no vacuum molding and the trials with vacuum molding demonstrates that the fibers in the web are highly moldable on Fabric 42. As will be discussed below, vacuum molding draws out the fibers in the regions of the web formed in the pockets of Fiber 42. The large fiber moldability means that the fibers are highly drawn out in this molding operation, which leads to the increased caliper and SAT capacity in the resulting product.

[0070] Figure 19 also evidences that greater fiber mobility is achieved with Fabric 42 by comparing the void volume of the basesheets from the trials at the fabric crepe levels. The absorbency of a sheet is directly related to void volume, which is essentially a measure of the space between the cellulose fibers. Void volume is measured by the procedure set forth in the aforementioned U.S. Patent No. 7,399,378. As shown in Figure 19, the void volume increased with the increasing fabric crepe in the trials using Fabric 42 where no vacuum molding was used. This indicates that the cellulose fibers were more separated from each other (i.e., de-bonded, with a lower resulting modulus) at each fabric crepe level in order to produce the additional void volume. Figure 19 further demonstrates that, when vacuum molding is used, Fabric 42 produces basesheets with more void volume than the conventional Fabric 45 at each fabric crepe level.

[0071] The fiber mobility when using Fabric 42 can also be seen in Figures 20(a), 20(b), 21(a), and 21(b), which are soft x-ray images of basesheets made using Fabric 42. As will be appreciated by those skilled in the art, soft x-ray imaging is a high-resolution technique that can be used for gauging mass uniformity in paper. The basesheets in Figures 20(a) and 20(b) where made with an 8 percent fabric crepe, whereas the basesheets in Figures 21(a) and 21(b) were made with a 25 percent fabric crepe. Figures 20(a) and 21(a) show fiber movement at a more "macro" level, with the images showing an area of 26.5 mm by 21.2 mm. Wave-like patterns of less mass (corresponding to the lighter regions in the images) can be seen with the higher fabric crepe (Figure 21(a)), but regions of less mass are not readily seen with the lower fabric crepe (Figure 20(a)). Figures 20(b) and 21(b) show the fiber movement at a more "micro" level, with the images showing an area of 13.2 mm by 10.6 mm. The cellulose fibers can clearly be seen as more distanced from each other and pulled apart with the higher fabric crepe (Figure 21(b)) than with the lower fiber crepe (Figure 20(b)). Collectively, the soft x-ray images further confirm that Fabric 42 provides for great fiber mobility with the higher localized mass movement being seen at the higher fabric crepe level than at the lower fabric crepe level.

[0072] Figures 17 and 18, and also Figure 19, show the results of the trials in terms of the furnish. Specifically, these figures show that Fabric 42 can produce comparable amounts of caliper, SAT capacity, and void volume when using the non-premium furnish as with the premium furnish. This is a very beneficial result as it demonstrates that the Fabric 42 can achieve outstanding results with a lower cost, non-premium furnish.

[0073] Because Fabric 42 has extra-long warp yarn knuckles, as with the other extra-long warp yarn knuckle fabrics described above, the products made with Fabric 42 may have multiple indented bars extending in a CD direction. The indented bars are again the result of folds being created in the areas of the web that are moved into the pockets of the structuring fabric. In the case of Fabric 42, it is believed that the aspect ratio of the length of the knuckles and the length across the pocket even further enhances the formation of the folds/indented bars. This is because the web is semi-restrained on the long warp knuckles while being more mobile within the pockets of Fabric 42. The result that the web can buckle or fold at multiple places along each pocket, which in turn leads to the CD indented bars seen in the products.

[0074] The indented bars formed in absorbent sheets made from Fabric 42 can be seen in Figures 22(a) through 22(e). These figures are images of the air-side of products made with Fabric 42 at different fabric creping levels but with no vacuum molding. The MD is in the vertical direction in all of these figures. Notably, instead of having sharply defined dome regions like the products described above, the products in Figures 22(a) through 22(e) are characterized by having parallel and near-continuous lines of projected regions substantially extending in the MD, with each of the extended projected regions including a plurality of indented bars extending across the projected regions in a substantially CD of the absorbent sheet. These projected rejections correspond to lines of pockets extending in the MD of Fabric 42. Between the projected regions are connecting regions that also extend substantially in the MD. The connecting regions correspond to the long warp yarn knuckles of Fabric 42.

[0075] The product in Figure 22(a) was made with a fabric crepe of 25%. In this product, the indented bars are very distinct. It is believed that this pattern of indented bars are the result of the fiber network on Fabric 42 experiencing a wide range of forces during the creping process, including in-plane compression, tension, bending, and buckling. All of these forces will contribute to the fiber mobility and fiber moldability, as discussed above. And, as a result of the near continuous nature of the projected regions extending in the MD, the enhanced fiber mobility and fiber moldability can take place in a near continuous manner along the MD.

[0076] Figures 22(b) through 22(e) show the configuration of products with less fabric creping as compared to the product shown in Figure 22(a). In Figure 22(b), the fabric crepe level used to form the depicted product was 15%, in Figure 22(c) the fabric crepe level was 10%, in Figure 22(d) the fabric crepe level was 8%, and in Figure 22(e) the fabric crepe level was 3%. As would be expected, the amplitude of the folds/indented bars can be seen to decrease with the decreasing fabric crepe level. However, it is notable that the frequency of the indented bars remains about the same through the fabric crepe levels. This indicates that the web is buckling/folding in the same locations relative to the knuckles and pockets in Fabric 42 regardless of fabric crepe level being used. Thus, beneficial properties stemming from the formation of folds/indented bars can be found even at lower fabric crepe levels.

[0077] In sum, Figures 22(a) through 22(e) show that the high pocket aspect ratio of Fabric 42 has the ability to uniformly exert decompacting energy to the web such that fiber mobility and fiber moldability are promoted over a wide fabric creping range. And, this fiber mobility and fiber moldability is a very significant factor in the outstanding properties, such as caliper and SAT capacity, found in the absorbent sheets made with Fabric 42.

[0078] Figures 23(a) through 24(b) are scanning electron microscopy images of the air sides of a product made with Fabric 42 (Figures 23(a) and 24(a)) and a comparison product made with Fabric 45 (Figures 23(b) and 24(b)). In these cases, the products were made with 30% fabric crepe and maximum vacuum molding. The center regions of the images in Figures 23(a) and 23(b) show areas made in the pockets of the respective fabrics, with areas surrounding the center regions corresponding to regions formed on knuckles of the respective fabrics. The cross sections shown in Figures 24(a) and 24(b) extend substantially along the MD, with an extended projected region of the Fabric 42 product being seen in Figure 24(a) and with multiple domes (as formed in multiple pockets) being seen in the Fabric 45 product shown in Figure 24(b). It can very clearly be seen that the fibers in the product made with Fabric 42 are much less densely packed than the cellulose fibers in the product made with Fabric 45. That is, the center dome regions in the Fabric 45 product are highly dense-as dense, if not more dense, than the connecting region surrounding the pocket region in the Fabric 42 product. Moreover, Figures 24(a) and 24(b) show the fibers to be much looser, i.e., less dense, in the Fabric 42 product than in the Fabric 45 product, with distinct fibers springing out from the Fabric 42 product structure in Figure 24(a). Figures 23(a) through 24(b) thereby further confirm that that Fabric 42 provides for a large amount of fiber mobility and fiber moldability creping process, which in turn results in regions of significantly reduced density in the absorbent sheet products made with the fabric. The reduced density regions provide for greater absorbency in the products. Further, the reduced density regions provide for more caliper as the sheet becomes more "puffed out" in the reduced density regions. Still further, the puffy, less dense regions will result in the product feeling softer to the touch.

[0079] Further trials were conducted using Fabric 42 to evaluate properties of converted towel products according to embodiments of our invention. For these trials, the same conditions were used as in the trials described in conjunction with TABLES 4 and 5. The basesheets were then converted to two-ply paper towel. TABLE 10 shows the converting specifications for these trials. Properties of products made in these trials are shown in TABLES 11-13.
TABLE 10
Conversion ProcessGluing
Number of Plies 2
Roll Diameter Varying
Sheet Count 60
Sheet Length 10.4
Sheet Width 11 in.
Roll Compression 6 - 12%
Emboss Process Following process of U.S. Patent No. 6,827,819 with the embossing pattern shown in U.S. Patent Design No. D504236 (which is incorporated by reference in its entirety)
Emboss Pattern Constant/Non-Varying
TABLE 11
Trial12345678910
Fabric 42 42 42 42 42 42 42 42 42 42
Fabric Crepe (%) 3 5 8 12 15 17.5 20 25 30 35
Furnish P P P P P P P P P P
Basis Weight (lbs/ream) 31.57 31.39 31.27 31.12 31.21 30.94 31.34 31.69 31.50 29.99
Caliper (mils/8 sheets) 152.9 183.1 185.9 204.1 215.2 218.7 225.2 236.0 229.9 223.3
MD Tensile (g/3 in) 3,296 2,716 2,786 2,651 2,454 2,662 2,624 2,405 2,553 2,363
CD Tensile (g/3 in) 2,656 2,479 2,503 2,526 2,420 2,617 2,668 2,478 2,279 2182
GM Tensile (g/3 in) 2,958 2,595 2,641 2,588 2,437 2,639 2,646 2,441 2,412 2271
Tensile Ratio 1.24 1.10 1.11 1.05 1.01 1.02 0.98 0.97 1.12 1.08
MD Stretch (%) 8.7 11.0 13.5 17.3 20.3 22.6 25.2 28.5 32.3 32.2
CD Stretch (%) 6.1 7.0 7.7 8.3 9.0 9.0 9.4 10.1 10.6 10.7
CD Wet Tensile - Finch (g/3 in) 797 724 738 747 746 788 803 729 728 707
CD Wet/Dry - Finch (%) 30.0 29.2 29.5 29.6 30.8 30.1 30.1 29.4 31.9 32.4
Perf Tensile (g/3") 608 534 577 572 562 601 560 495 616 514
SAT Capacity (g/m2) 344 404 385 416 450 465 479 530 527 520
SAT Capacity (g/g) 6.7 7.9 7.6 8.2 8.9 9.2 9.4 10.3 10.3 10.6
SAT Rate (g/sec0.5) 0.09 0.15 0.10 0.12 0.14 0.15 0.15 0.18 0.17 0.19
GM Break Modulus (g/%) 407.2 295.3 257.7 216.5 180.4 183.4 172.7 144.8 130.0 122.8
Roll Diameter (in) 4.57 4.93 5.01 5.03 5.07 5.08 5.15 5.35 5.12 5.14
Roll Compression (%) 12.1 11.56 12.38 10.06 7.89 7.81 6.93 8.78 6.90 7.52
Sensory Softness N/C 10.1 9.7 N/C N/C N/C 9.0 9.2 N/C N/C
TABLE 12
Trial11121415161718192021
Fabric 42 42 42 42 42 42 42 42 42 42
Fabric Crepe (%) 35 5 8 12 15 17.5 20 25 20 25
Furnish P NP NP NP NP NP NP NP NP NP
Basis Weight (lbs/ream) 29.99 31.41 31.67 31.09 31.61 31.34 31.60 31.85 31.43 31.26
Caliper (mils/8 sheets) 223.3 175.6 183.0 197.8 213.4 212.3 220.6 220.3 200.3 208.2
MD Tensile (g/3 in) 2,363 2,878 2,885 2,481 2,447 2,385 2,397 2374 2,684 2424
CD Tensile (g/3 in) 2182 2,495 2,621 2,523 2,563 2,615 2,523 2341 2,545 2591
GM Tensile (g/3 in) 2271 2,680 2,750 2,502 2,505 2,497 2,460 2357 2,613 2506
Tensile Ratio 1.08 1.15 1.10 0.98 0.95 0.91 0.95 1.01 1.05 0.94
MD Stretch (%) 32.2 10.1 12.9 16.9 19.0 20.5 23.0 28.5 23.8 27.4
CD Stretch (%) 10.7 7.2 7.6 8.2 8.1 8.6 8.8 9.6 8.5 8.4
CD Wet Tensile - Finch (g/3 in) 707 767 828 825 752 758 752 770 865 738
CD Wet/Dry - Finch (%) 32.4 30.7 31.6 32.7 29.3 29.0 29.8 32.9 34.0 28.5
Perf Tensile (g/3 in) 514 644 668 575 586 496 580 602 614 530
SAT Capacity (g/m2) 520 362 402 430 497 490 520 514 473 499
SAT Capacity (g/g) 10.6 7.1 7.8 8.5 9.7 9.6 10.1 9.9 9.2 9.8
SAT Rate (g/sec0.5) 0.19 0.11 0.14 0.14 0.22 0.23 0.22 0.20 0.19 0.24
GM Break Modulus (g/%) 122.8 313.3 278.5 211.4 201.2 188.2 171.6 144.0 182.3 164.6
Roll Diameter (in) 5.14 4.79 4.84 4.89 5.13 5.05 5.31 5.10 5.03 5.01
Roll Compression (%) 7.52 8.70 9.02 7.08 9.48 7.52 11.74 6.86 10.14 7.71
Sensory Softness N/C 9.4 N/C N/C 9.2 N/C 9.2 9.1 N/C 8.8
TABLE 13
Trial222324252652728
Fabric 42 45 45 45 45 45 45
Fabric Crepe (%) 25 3 5 8 15 20 30
Furnish NP NP NP NP NP NP NP
Basis Weight (lbs/ream) 26.22 31.20 31.53 30.83 31.11 31.24 30.98
Caliper (mils/8 sheets) 120.3 130.5 137.3 159.3 164.1 172.5 182.3
MD Tensile (g/3 in) 2687 2,939 2,742 2,787 2,647 2,649 2,629
CD Tensile (g/3 in) 2518 2,569 2,510 2,664 2,726 2,647 2,594
GM Tensile (g/3 in) 2601 2,748 2,623 2,724 2,686 2,648 2,611
Tensile Ratio 1.07 1.14 1.09 1.05 0.97 1.00 1.01
MD Stretch (%) 30.0 8.4 9.3 18.7 18.1 21.7 31.1
CD Stretch (%) 7.9 5.1 5.0 6.3 6.4 7.0 7.7
CD Wet Tensile - Finch (g/3 in) 793 732 767 764 756 766 789
CD Wet/Dry - Finch (%) 31.5 28.5 30.5 28.7 27.7 28.9 30.4
Perf Tensile (g/3 in) 613 621 528 593 637 591 570
SAT Capacity (g/m2) 215 298 314 384 386 406 404
SAT Capacity (g/g) 5.0 5.9 6.1 7.7 7.6 8.0 8.0
SAT Rate (g/sec0.5) 0.04 0.10 0.10 0.14 0.14 0.15 0.14
GM Break Modulus (g/%) 168.2 422.4 385.5 276.5 249.2 213.6 166.6
Roll Diameter (in) 5.24 4.35 4.36 4.44 4.54 4.61 4.55
Roll Compression (%) 6.16 14.5 13.9 10.0 9.1 8.4 5.2
Sensory Softness N/C N/C 9.3 N/C N/C 8.7 8.4


[0080] Note that Trial 22 only formed a one-ply product, but was otherwise converted in the same manner as the other trials.

[0081] The results shown in TABLES 11-13 demonstrate the excellent properties that can be achieved using a long warp warn knuckle fabric according to our invention. For example, the final products made with Fabric 42 had higher caliper and higher SAT capacity than the comparison products made with Fabric 45. Further, the results in TABLES 11-13 demonstrate that very comparable products can be made with Fabric 42 regardless of whether a premium or a non-premium furnish is used.

[0082] Based on properties of the products made in the trials described herein, it is clear that the long warp yarn knuckle structuring fabrics described herein can be used in methods that provide products having outstanding combinations of properties. For example, the long warp yarn knuckle structuring fabrics described herein can be used in conjunction with the non-TAD process described generally above and specifically set forth in the aforementioned '563 patent, (wherein the papermaking furnish is compactively dewatered before creping) to form an absorbent sheet that has SAT capacities of at least about 9.5 g/g and at least about 500 g/m2. Further, this absorbent sheet can be formed in the method while using a creping ratio of less than about 25%. Even further, the method and long warp yarn knuckle structuring fabrics can be used to produce an absorbent sheet that has SAT capacities of at least about at least about 10.0 g/g and at least about 500 g/m2, has a basis weight of less than about 30 lbs/ream, and a caliper 220 mils/8 sheets. We believe that this type of method has never created such an absorbent sheet before.

[0083] Although this invention has been described in certain specific exemplary embodiments, many additional modifications and variations would be apparent to those skilled in the art in light of this disclosure. It is, therefore, to be understood that this invention may be practiced otherwise than as specifically described. Thus, the exemplary embodiments of the invention should be considered in all respects to be illustrative and not restrictive, and the scope of the invention to be determined by any claims supportable by this application and the equivalents thereof, rather than by the foregoing description.

Industrial Applicability



[0084] The invention can be used to produce desirable paper products such as hand towels or toilet paper. Thus, the invention is applicable to the paper products industry.

[0085] The present specification further discloses the following embodiments:
  1. 1. An absorbent cellulosic sheet that has a first side and a second side, the absorbent sheet comprising:

    a plurality of domed regions projecting from the first side of the sheet, each of the domed regions including a plurality of indented bars extending across a respective domed region in a substantially cross machine direction (CD) of the absorbent sheet, wherein the domed regions are extended substantially along the machine direction (MD) of the absorbent sheet; and

    connecting regions forming a network interconnecting the domed regions of the absorbent sheet.

  2. 2. An absorbent sheet according to embodiment 1, wherein each of the domed regions includes about six indented bars.
  3. 3. An absorbent sheet according to embodiment 1, wherein at least some of the domed regions include eight indented bars.
  4. 4. An absorbent sheet according to embodiment 1, wherein the domed regions extend a distance of about 2.5 mm to about 3.0 mm in the MD of the absorbent sheet.
  5. 5. An absorbent sheet according to embodiment 1, wherein each of the domed regions is positioned adjacent to two other domed regions such that a line of staggered domed regions extends substantially in the MD of the absorbent sheet.
  6. 6. An absorbent sheet according to embodiment 1, wherein the indented bars are spaced about 0.5 mm apart in the MD of the absorbent sheet.
  7. 7. An absorbent sheet according to embodiment 1, wherein the domed regions have a substantially rectangular shape.
  8. 8. An absorbent cellulosic sheet that has a first side and a second side, the absorbent sheet comprising:

    a plurality of domed regions projecting from the first side of the sheet, wherein each domed region is positioned adjacent to another domed region such that a staggered line of domed regions extends substantially along the machine direction (MD) of the absorbent sheet; and

    connecting regions forming a network interconnecting the domed regions of the absorbent sheet, wherein each connecting region is substantially continuous with two other connecting regions such that substantially continuous lines of connecting regions extend in a stepped manner along the MD of the absorbent sheet.

  9. 9. An absorbent sheet according to embodiment 8, wherein each of the domed regions includes a plurality of indented bars extending across the domed regions in the cross machine direction (CD) of the absorbent sheet.
  10. 10. An absorbent sheet according to embodiment 9, wherein at least some of the domed regions includes eight indented bars.
  11. 11. An absorbent sheet according to embodiment 8, wherein each of the domed regions extends a distance of about 2.5 mm to about 3.0 mm in the MD of the absorbent sheet.
  12. 12. An absorbent sheet according to embodiment 8, wherein the domed regions are rectangular-shaped.
  13. 13. An absorbent cellulosic sheet that has a first side and a second side, the absorbent sheet comprising:

    a plurality of domed regions projecting from the first side of the sheet, wherein each of the domed regions extends (i) a distance of at least 2.5 mm in the machine direction (MD) of the absorbent sheet, and (ii) includes an indented bar extending across the domed region in a substantially cross machine direction (CD) of the absorbent sheet, and wherein the indented bar extends a depth of at least about 45 microns below adjacent portions of the domed region; and

    connecting regions forming a network interconnecting the domed regions of the absorbent sheet.

  14. 14. An absorbent sheet according to embodiment 13, wherein each of the domed regions includes a plurality of indented bars.
  15. 15. An absorbent sheet according to embodiment 13, wherein the indented bars extend a depth of about 90 microns below the adjacent portions of the domed regions.
  16. 16. An absorbent sheet according to embodiment 13, wherein the domed regions extend a distance of about 1.0 mm in the CD of the absorbent sheet.
  17. 17. An absorbent sheet according to embodiment 13, wherein each of the domed regions extends at least about 2.5 mm to about 5.5 mm in the MD of the absorbent sheet.
  18. 18. An absorbent sheet according to embodiment 13, wherein the indented bar extends a depth of about 45 microns to about 160 microns below adjacent portions of the domed region.
  19. 19. An absorbent sheet according to embodiment 13, wherein each domed region is positioned adjacent to another domed region such that staggered lines of domed regions extend substantially along the MD of the absorbent sheet, and
    wherein each connecting region is substantially continuous with two other connecting regions, such that substantially continuous lines of connecting regions extend in a stepped manner along the MD of the absorbent sheet.
  20. 20. An absorbent sheet according to embodiment 19, wherein connecting regions extending in the MD of the absorbent sheet extend a distance of about 0.5 mm in the CD of the absorbent sheet.
  21. 21. A method of making an absorbent cellulosic sheet, the method comprising:

    forming an aqueous cellulosic web on a structuring fabric in a papermaking machine, the structuring fabric including knuckles formed on warp yarns of the structuring fabric, with the knuckles having a length in the machine direction (MD) of the absorbent sheet and a width in the cross machine direction (CD) of the absorbent sheet, wherein a planar volumetric density index of the structuring fabric multiplied by the ratio of the length of the knuckles to the width of the knuckles width is at least about 43;

    dewatering the cellulosic web on the structuring fabric; and

    drying the cellulosic web to form the absorbent cellulosic sheet.

  22. 22. A method according to embodiment 21, wherein the length of the knuckles in the MD of the structuring fabric is about 2.2 mm to about 5.6 mm.
  23. 23. A method according to embodiment 21, wherein a pocket density of the structuring fabric is about 10 cm-2 to about 47 cm-2.
  24. 24. A method according to embodiment 21, wherein the planar volumetric density index of the structuring fabric multiplied by the ratio of the length of the knuckles and the width of the knuckles width is about 43 to about 50.
  25. 25. An absorbent cellulosic sheet that has a first side and a second side, the absorbent sheet comprising:

    projected regions extending from the first side of the sheet, the projected regions extending substantially in the machine direction (MD) of the absorbent sheet, each of the projected regions including a plurality of indented bars extending across the projected regions in a substantially cross machine direction (CD) of the absorbent sheet, and the projected regions being substantially parallel to each other; and

    connecting regions between the projected regions, the connecting regions extending substantially in the MD.

  26. 26. An absorbent sheet according to 25, wherein the sheet has a basis weight of less than about 27 lbs/ream and a caliper of less than about 180 mils/8 sheets.
  27. 27. An absorbent sheet according to 25, wherein the sheet has a basis weight of greater than about 35 lbs/ream and a caliper of greater than about 225 mils/8 sheets.
  28. 28. A method of making a fabric-creped absorbent cellulosic sheet, the method comprising:

    compactively dewatering a papermaking furnish to form a web having a consistency of about 30 percent to about 60 percent;

    creping the web under pressure in a creping nip between a transfer surface and a structuring fabric, the structuring fabric including knuckles formed on warp yarns of the structuring fabric, with the knuckles having a length in the machine direction (MD) of the absorbent sheet and a width in the cross machine direction (CD) of the absorbent sheet, wherein a planar volumetric density index of the structuring fabric multiplied by the ratio of the length of the knuckles to the width of the knuckles width is at least about 43; and

    drying the web to form the absorbent cellulosic sheet.

  29. 29. A method according to embodiment 28, wherein the length of the knuckles in the MD of the structuring fabric is about 2.2 mm to about 5.6 mm.
  30. 30. A method according to embodiment 28, wherein the planar volumetric density index of the structuring fabric multiplied by the ratio of the length of the knuckles and the width of the knuckles width is about 43 to about 250.
  31. 31. A method according to embodiment 28, wherein the transfer surface is part of a backing roll or an endless belt.
  32. 32. A method according to embodiment 28, wherein a creping ratio is defined by the speed of the transfer surface relative to the speed of the structuring fabric, and the creping ratio is about 3% to about 25%.
  33. 33. A method of making a fabric-creped absorbent cellulosic sheet, the method comprising:

    compactively dewatering a papermaking furnish to form a web;

    creping the web under pressure in a nip between a transfer surface and a structuring fabric, the structuring fabric having machine direction (MD) yarns that form (i) knuckles extending in a substantially MD lines along the structuring fabric, and (ii) substantially continuous lines of pockets extending in substantially MD lines along the structuring fabric between the lines of knuckles, and the structuring fabric having cross machine direction (CD) yarns that are completely located below a plane defined by the knuckles of the MD yarns at a top surface of the structuring fabric; and

    drying the web to form the absorbent cellulosic sheet.

  34. 34. A method according to embodiment 33, wherein the MD yarns in the top surface of the structuring fabric slope downwards from the plane defined by the MD knuckles to positions below CD yarns of the structuring fabric.
  35. 35. A method according to embodiment 33, wherein the length of the knuckles in the MD of the structuring fabric is about 2.2 mm to about 7.5 mm.
  36. 36. A method according to embodiment 33, wherein the length of the knuckles in the MD of the structuring fabric is about 2.2 mm to about 5.6 mm.
  37. 37. A method according to embodiment 33, wherein the planar volumetric density index of the structuring fabric multiplied by the ratio of the length of the knuckles and the width of the knuckles width is about 43 to about 250.
  38. 38. A method according to embodiment 33, wherein the transfer surface is part of a backing roll or an endless belt.
  39. 39. A method according to embodiment 33, where the papermaking furnish is compactively dewatered such that the web has a consistency of about 30 percent to about 60 percent before entering the nip.
  40. 40. A method according to embodiment 33, wherein a creping ratio is defined by the speed of the transfer surface relative to the structuring fabric, and the creping ratio is about 3% to about 25%.
  41. 41. A method of making a fabric-creped absorbent cellulosic sheet, the method comprising:

    compactively dewatering a papermaking furnish to form a web having a consistency of about 30 percent to about 60 percent;

    creping the web under pressure in a creping nip between a transfer surface and a structuring fabric; and

    drying the web to form the absorbent cellulosic sheet,

    wherein the absorbent sheet has SAT capacities of at least about 9.5 g/g and at least about 500 g/m2, and

    wherein a creping ratio is defined by the speed of the transfer surface relative to the speed of the structuring fabric, and the creping ratio is less than about 25%.

  42. 42. The method according to embodiment 41, wherein the SAT capacities of the absorbent sheet are at least about 10.0 g/g and at least about 500 g/m2.
  43. 43. The method according to embodiment 41, wherein the basis weight of the absorbent sheet is less than about 30 lbs/ream.
  44. 44. The method according to embodiment 41, wherein the caliper of at least about 220 mils/8 sheets.



Claims

1. A method of making a fabric-creped absorbent cellulosic sheet, the method comprising:

compactively dewatering a papermaking furnish to form a web;

creping the web under pressure in a nip between a transfer surface and a structuring fabric, the structuring fabric having machine direction (MD) yarns that form (i) knuckles extending in substantially MD lines along the structuring fabric, and (ii) substantially continuous lines of pockets extending in substantially MD lines along the structuring fabric between the lines of knuckles, and the structuring fabric having cross machine direction (CD) yarns that are completely located below a plane defined by the knuckles of the MD yarns at a top surface of the structuring fabric; and drying the web to form the absorbent cellulosic sheet.


 
2. A method according to claim 1, wherein the MD yarns in the top surface of the structuring fabric slope downwards from the plane defined by the MD knuckles to positions below CD yarns of the structuring fabric.
 
3. A method according to claim 1, wherein the length of the knuckles in the MD of the structuring fabric is about 2.2 mm to about 7.5 mm.
 
4. A method according to claim 1, wherein the length of the knuckles in the MD of the structuring fabric is about 2.2 mm to about 5.6 mm.
 
5. A method according to claim 1, wherein the planar volumetric density index of the structuring fabric multiplied by the ratio of the length of the knuckles and the width of the knuckles width is about 43 to about 250.
 
6. A method according to claim 1, wherein the transfer surface is part of a backing roll or an endless belt.
 
7. A method according to claim 1, wherein a creping ratio is defined by the speed of the transfer surface relative to the structuring fabric, and the creping ratio is about 3% to about 25%.
 
8. A method according to claim 1, wherein the papermaking furnish is compactively dewatered such that the web has a consistency of about 30 percent to about 60 percent before entering the nip.
 
9. A method according to claim 8, wherein the absorbent sheet has SAT absorbent capacities of at least about 9.5 g/g and at least about 500 g/m2.
 
10. A method according to claim 9, wherein a creping ratio is defined by the speed of the transfer surface relative to the speed of the structuring fabric, and the creping ratio is less than about 25%.
 
11. A method according to claim 10, wherein the SAT capacities of the absorbent sheet are at least about 10.0 g/g and at least about 500 g/m2.
 
12. A method according to claim 10, wherein the basis weight of the absorbent sheet is less than about 30 lbs/ream.
 
13. A method according to claim 10, wherein the absorbent sheet has a caliper of at least about 220 mils/8 sheets.
 




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REFERENCES CITED IN THE DESCRIPTION



This list of references cited by the applicant is for the reader's convenience only. It does not form part of the European patent document. Even though great care has been taken in compiling the references, errors or omissions cannot be excluded and the EPO disclaims all liability in this regard.

Patent documents cited in the description