TW201742967A - Soft absorbent sheets, structuring fabrics for making soft absorbent sheets, and methods of making soft absorbent sheets - Google Patents

Abstract

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 projected regions and connecting regions that connect the projected regions. The projected regions include folds that are curved relative to a machine direction of the absorbent sheet, with ends of the curved folds being on opposite sides of the projected regions, and with apexes of the curved folds being positioned downstream in the machine direction of the absorbent sheet. The absorbent sheets can be formed by structuring fabrics that have angled lines of warp yarn knuckles.

Description

Soft absorbent sheet, structured fabric for making soft absorbent sheet, and method of making soft absorbent sheet

CROSS REFERENCE TO RELATED APPLICATIONS This application is a continuation-in-part of U.S. Patent Application Serial No. S15/175,949, filed on Jun. 7, 2016, which is incorporated herein by reference. Patent Application Serial No. 62/172,659, the entire disclosure of which is hereby incorporated by reference in its entirety in its entirety in its entirety herein in Field of invention

Our invention relates to paper products such as absorbent sheets. Our invention also relates to a method of making a paper product such as an absorbent sheet, and to a structured fabric for use in the manufacture of a paper product such as an absorbent sheet.

BACKGROUND OF THE INVENTION The use of fabrics in the papermaking industry to impart structure to paper products is well known. More specifically, it is well known to form paper products by pressing a malleable web of cellulosic fibers onto a fabric and then drying the web. The resulting paper product thereby forms a molded shape corresponding to the surface of the fabric. The resulting paper product thus also has properties resulting from the molded shape, such as special paper thickness and absorbency. As such, a myriad of structured fabrics have been developed for use in the papermaking process to provide articles with different shapes and characteristics. Furthermore, the fabric can be woven into a nearly unlimited number of patterns for potential applications in the papermaking process.

An important property of many absorbent paper products is the softness desired by the consumer, such as a soft tissue. However, many of the techniques used to increase the softness of paper products have the effect of reducing other desirable properties of the paper product. For example, a calendered base sheet that is part of the process of producing a tissue can increase the softness of the resulting tissue, but calendering also has the effect of reducing the paper thickness and absorbency of the tissue. On the other hand, techniques for improving many other important characteristics of paper products have the effect of reducing the softness of the paper product. For example, the use of wet and dry strength resins in the papermaking process can improve the potential strength of the paper product, but the wet and dry reinforcing resins also reduce the perceived softness of the + product.

For these reasons, it is desirable to make softer paper products, such as absorbent sheets. Furthermore, it would be desirable to be able to manufacture such relatively soft absorbent sheets by manipulating the structured fabric used in the process of making the absorbent sheet.

SUMMARY OF THE INVENTION According to one aspect, our invention provides an absorbent sheet of cellulosic fibers. The absorbent cellulosic sheet comprises a plurality of projecting regions projecting from the absorbent sheet, wherein the projecting regions comprise a folded fold relative to the machine longitudinal direction of the absorbent sheet. The curved folded ends are positioned on opposite sides of the projecting region such that in the machine longitudinal direction of the absorbent sheet, one of each of the curved folded ends is positioned downstream of the other end of the curved fold. The apex of the curved fold is positioned longitudinally downstream of the machine of the absorbent sheet. Further, the connection region connects the protruding regions of the absorbent sheet.

According to another aspect, our invention provides an absorbent cellulose sheet. Most of the projecting regions project from the absorbent sheet, wherein the projecting region includes a machine transversely projecting region relative to the absorbent sheet comprising a fold that is curved relative to the machine longitudinal direction of the absorbent sheet. The folded ends are located on opposite sides of the projecting region and the curved fold has a radius of curvature of from about 0.5 mm to about 2.0 mm. Further, the connection region connects the protruding regions of the absorbent sheet.

According to another aspect, our invention provides a paper web. The paper web comprises a projecting region of a plurality of self-made paper webs, wherein the projecting region comprises a longitudinally curved fold relative to the machine of the absorbent sheet, the curved folded ends being located on opposite sides of the projecting region and allowing for papermaking In the longitudinal direction of the machine of the web, one of each of the curved folded ends is positioned downstream of the other end of the curved fold. The apex of the curved fold is positioned longitudinally downstream of the machine of the paper web. Furthermore, the joining area forms a network that connects the protruding areas of the paper web.

According to still another aspect, our invention provides a method of making a fabric-creped cellulose absorbent sheet. The method includes compacting the papermaking furnish to form a web. The method of the present invention also includes subjecting the web to creping in a creping nip between the transfer surface and the structured fabric under pressure. The structured fabric includes knuckle-like projections formed on the warp yarns of the structured fabric, the knuckled projections being positioned in a straight line at an oblique angle relative to the machine longitudinal direction of the fabric, wherein the angular extent of the straight line relative to the machine longitudinal direction of the fabric It is from about 10° to about 30°. Further, the method of the present invention includes the step of drying the web to form a cellulose absorbent sheet.

According to still another aspect, our invention provides a cellulose absorbent sheet comprising a plurality of projecting regions projecting from the absorbent sheet, the projecting region comprising a folded fold relative to the machine longitudinal direction of the absorbent sheet, and a curved folded The end portions are on opposite sides of the projecting region. The normalized folded curvature ratio of the absorbent sheet is less than about 4. The absorbent sheet also includes a joining region that forms a network connecting the protruding regions of the absorbent sheet.

DETAILED DESCRIPTION OF THE INVENTION 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 an outstanding combination of properties superior to those of other absorbent paper products known in the art. In some particular embodiments, absorbent paper articles according to our invention have a combination of properties that are particularly suitable for absorbing hand towels, facial tissues or toilet paper.

The term "paper product" is used herein to encompass any article comprising papermaking fibers having cellulose as the primary component. This includes, for example, paper towels, toilet paper, facial tissue and the like which are commercially available. Papermaking fibers include virgin pulp or regenerated (secondary) cellulosic fibers, or fiber blends comprising cellulosic fibers. Wood fibers include, for example, wood fibers obtained from deciduous and coniferous trees, including soft wood fibers such as northern and southern softwood cowhide fibers, and hardwood fibers such as eucalyptus, maple, birch, poplar or the like. Examples of fibers suitable for making articles of our invention include non-wood fibers such as cotton or cotton derivatives, abaca, kenaf, indica, flax, reed grass, straw, jute, bagasse, milkweed fibers and Pineapple leaf fiber.

"Ingredients" and like specific terms are meant to include aqueous compositions of papermaking fibers, as well as wet strength resins, debonders, and the like, including papermaking fibers and, optionally, for making paper products. A variety of different ingredients can be used in the embodiments of our invention, and specific ingredients are disclosed in the examples discussed below. In some specific examples, the ingredients are used in accordance with the specifications in U.S. Patent No. 8,080,130, the entire disclosure of which is incorporated herein by reference. Among other things, the ingredients in this patent include cellulosic long fibers having a thickness of at least about 15.5 mg/100 mm. Embodiments of the ingredients are also indicated in the examples discussed below.

As used herein, the initial fiber and liquid mixture that is dried into a finished product during the paper making process will be referred to as a "web" and/or a "nascent" web. The dried single layer product from the papermaking process will be referred to as the "base sheet." Furthermore, the product of the papermaking process can be referred to as an "absorbent sheet." In this regard, the absorbent sheet can be the same as a single substrate sheet. Alternatively, the absorbent sheet may comprise a plurality of substrate sheets as if forming a multilayer structure. Further, the absorbent sheet may have been subjected to additional processing after the initial substrate sheet forming process so that the paper product can be formed from the converted substrate sheet. "Absorbent tablets" include products sold in the market, such as hand towels.

When describing our invention herein, the terms "machine orientation" (MD) and "machine orientation" (CD) will be used in accordance with their well-known meaning in the art. In other words, the machine longitudinal direction (MD) of a fabric or other structure means the direction in which the structure moves on the paper machine during the paper making process, and the machine direction (CD) means the direction of the machine longitudinal direction (MD) across the structure. Similarly, when referring to a paper product, the machine longitudinal direction (MD) of the paper product means the direction of the article on the article moving on the paper machine during the paper making process, and the machine direction (CD) of the article means the machine longitudinal direction across the article. The direction of (MD). From the machine longitudinal (MD) angle of the paper product, "downstream" means the area formed before the "upstream" area.

Figure 1 shows a paper machine 200 that can be used to make a paper product according to our invention. A detailed description of the structure and operation of the paper machine 200 can be found in the commonly assigned U.S. Patent No. 7,494,563 (the ' 563 patent), the entire disclosure of which is incorporated herein by reference. In particular, the '563 patent describes a papermaking process that does not use air through drying (TAD). The following is a brief summary of the method of forming an absorbent sheet using the paper machine 200.

The paper machine 200 is a three-fabric loop machine including a pressing section 100 for performing a creping operation. Upstream of the pressing section 100 is a forming section 202. The forming section 202 includes a headbox 204 that deposits an aqueous furnish on a forming wire 206 supported by rolls 208 and 210, thereby forming an initial aqueous cellulosic fibrous web 116. The forming section 202 also includes a forming roll 212 that supports the papermaking felt 102 such that the web 116 is also formed directly on the papermaking felt 102. The blanket route 214 extends around the suction steering roll 104 and then reaches the support press section 216 where the web 116 is stored on the pressure roller 108. The web 116 is wet pressed while the web 116 is being transferred to the pressure roller 108, which carries the web 116 to the creping nip 120. However, in other embodiments, the web 116 is not transferred to the pressure roller 108, but instead is transferred from the paper blanket route 214 to the endless belt in the dewatering nip, and then the web 116 is brought to the crepe by the endless belt. Roll gap 120. An example of such a construction can be found in U.S. Patent No. 8,871,060, the disclosure of which is incorporated herein by reference in its entirety.

The web 116 is transferred to the structured fabric 112 in the creping nip 120 and then evacuated by a vacuum forming box 114. After the creping operation, the creping adhesive was applied to the surface of a Yankee dryer 218, and the web 116 was deposited in a press nip 217 on a Yankee dryer (Yankee). Dryer) 218. The web 116 is dried on a heated Yankee dryer 218, and the web 116 is also dried by impacting the air at a high jet velocity in a hood surrounding the Yankee dryer 218. As the Yankee dryer 218 rotates, the web 116 is peeled off from the dryer 218 at location 220. Next, the web 116 can then be wound onto a storage reel (not shown). In steady state, the operation of the spool can be slower than the Yankee dryer 218 so that the web can be further creped. Optionally, the creping blade 222 can be used to conventionally dry the web as the web 116 leaves the Yankee dryer 218.

In the creping nip 120, the web 116 is transferred to the top side of the structured fabric 112. The creping nip 120 is defined by the pressure roller 108 and the structured fabric 112, and the structured fabric 112 is pressed against the pressure roller 108 by the creping roller 110. When the web is transferred to the structured fabric 112, since the web 116 still has a high water content, the web is deformable such that a portion of the web can be wrapped into a pocket formed between the yarns constituting the structured fabric 112. The shape (the pocket of the structured fabric will be described in detail below). The structured fabric 112 moves much slower than the papermaking felt 102 during a particular papermaking process. Thus, as the web 116 is transferred to the structured fabric 112, the web is creped.

The evacuation applied by the vacuum forming box 114 may also assist in entraining the web 116 into the pocket of the structured fabric 112, as will be described below. As it travels along the structured fabric 112, the web 116 reaches a highly uniform state because most of the moisture has been removed. Thereby, the web 116 is permanently imparted with a shape due to the structured fabric 112 having a shape including a projecting region where the web 116 is drawn into the pocket of the structured fabric 112.

The substrate sheet produced by the paper machine 200 can also be further processed as is known in the art to convert the substrate sheet into a particular article. For example, the substrate sheet can be embossed, and the two substrate sheets can be combined into a multilayer article. Details of such conversion processing are well known in the art.

Using the method described in the '563 patent above, when transferred to the top side of the structured fabric 112, the web 116 is dewatered to a level similar to that of other papermaking processes, such as TAD processes, with a higher consistency. . In other words, the web 116 is compressionally dewatered to have a consistency (i.e., solids content) of from about 30 percent to about 60 percent prior to entering the creping nip 120. In the creping nip 120, the web 116 is subjected to a load of from about 30 pounds per linear inch (PLI) to about 200 PLI. Furthermore, there is a speed difference between the pressure roller 108 and the structured fabric 112. This speed difference is referred to as the fabric crepe percentage and can be calculated from: Fabric crepe % = S ₁ /S ₂ - 1 where S ₁ is the speed of the pressure roller 108 and S ₂ is the speed of the structured fabric 112. In particular embodiments, the fabric crepe percentage, or crepe ratio, can be any value between about 3% and about 100%. The web consistency, the velocity differential occurring at the creping nip 120, the pressure applied at the creping nip 120, and the combination of the structured fabric 112 and the geometry of the creping nip 120 act on the rearranged fibers. Fibres, while web 116 still has sufficient flexibility to make structural changes. In particular, without intending to be limited by theory, the forming surface speed of the slower structured fabric 112 is believed to cause the web 116 to be substantially molded into openings in the structured fabric 116, the fibers being proportional to the creping ratio. re-locate.

While a particular process has been described in conjunction with the paper machine 200, it will be apparent to those of ordinary skill in the art that the invention disclosed herein is not limited to the papermaking process described above. For example, our invention can be related to the TAD papermaking process relative to the non-TAD process described above. An example of a TAD papermaking process can be found in U.S. Patent No. 8,080,130, the disclosure of which is incorporated herein by reference.

2 is a diagram showing details of a portion of a web contact side of a structured fabric 300 having a configuration of a paper product according to an embodiment of our invention. The structured fabric 300 includes warp yarns 302 that run in machine direction (MD) when the fabric is used in a papermaking process, and weft yarns 304 that run in machine cross direction (CD). The warp and weft yarns 302 and 304 are woven together such that the body of the structured fabric 300 can be formed. The web-containing surface of the structured fabric 300 is formed by knuckle projections (the contours of the two knuckled projections are drawn in Figures 2 and labeled 306 and 310), and the knuckle projections are formed. On the warp yarns 302, but no knuckles are formed on the weft yarns 304. However, it is worth noting that while the structured fabric 300 shown in Figure 2 has only knuckle projections on the warp yarns 302, our invention is not limited to structuring with only warp knuckle projections. The fabric, on the other hand, comprises a fabric having both warp and weft knuckle projections. In fact, fabrics having only warp knuckle protrusions and fabrics having both warp and weft knuckle protrusions will be described in detail below.

The knuckle projections 306 and 310 in the structured fabric 300 are planes that define the surface that the web 116 contacts during the papermaking operation. A pocket 308 (one of which is shown in outline area in FIG. 2) is defined in the region between the knuckle projections 306 and 310. Portions of the web 116 that are not in contact with the knuckle protrusions 306 and 310 are drawn into the pocket 308 as described above. The portion of the web 116 that is drawn into the pocket 308 results in the formation of a raised area found in the resulting paper product.

Those of ordinary skill in the art will appreciate the significant lengths of the MD warp knuckle protrusions 306 and 310 in the structured fabric 300, and it will be further appreciated that the fabric 300 is shaped such that the long warp knuckle projections 306 and 310 depicts a long pocket in the MD direction. In a particular embodiment of our invention, warp knuckle protrusions 306 and 310 have a length of from about 2 mm to about 6 mm. Most of the structured fabrics known in the art have shorter warp knuckle projections (even if the fabric has any warp knuckle projections). As will be described hereinafter, the longer warp knuckle protrusions 306 and 310 provide a larger contact area to the web 116 during the paper making process and are believed to be relatively short warp knuckles relative to conventional yarns. Protrusions, according to our invention, absorb at least some of the reasons for the increase in softness.

In order to quantify the parameters of the structured fabrics described herein, U.S. Patent Application Publication Nos. 2014/0133734, 2014/0130996, 2014/0254885 and 2015/0129145 (hereinafter referred to as "fabric properties" are described in the commonly assigned U.S. Patent Application Publication Nos. Public information"). The disclosure of these fabric characterization publications is incorporated herein by reference in its entirety. Such fabric characterization techniques allow for easy quantification of parameters of the structured fabric, including knuckle-like protrusion length and width, knuckle-like protrusion density, pocket area, bag density, bag depth, and bag volume.

Figures 3A through 3E illustrate some of the characteristics of structured fabrics made according to embodiments of our invention, which are labeled as fabrics 1 through 15. Figure 3F also shows the characteristics of a conventional structured fabric, which are labeled as fabrics 16 and 17. The structured fabric forms shown in Figures 3A through 3F can be manufactured by a number of manufacturers, including the Albany International of Rochester, New Hampshire, and the Heidenheim, Germany. Voith GmbH of Heidenheim, Germany. The fabrics 1 to 15 have a long warp knuckle-like projection fabric such that the major contact area of most of the fabrics 1 to 15 comes from the warp yarn fingers relative to the weft knuckle projections (even if the fabric has weft knuckle projections) Jagged protrusions. Fabrics 16 and 17 having shorter warp knuckle protrusions are provided for comparison. All of the characteristics shown in Figures 3A through 3F were determined using the techniques described in the aforementioned fabric characterization publications using the non-rectangular parallelogram calculations described in the fabric characterization publication. It is to be noted that the expression "N/C" in FIGS. 3A to 3F means a special characteristic that is not determined.

The breathability of the structured fabric is another property that can affect the properties of the paper product made from the structured fabric. The breathability of the structured fabric is measured according to equipment and testing well known in the art, such as the Frazier® differential pressure breathability of the Frazier Precision Instrument Company of Hagerstown, Maryland. Sex measuring instrument. In general, the structured fabric used to make the long warp knuckle projections of paper products according to our invention has a high degree of breathability. In a particular embodiment of our invention, the structured fabric of the long warp knuckle projections has a gas permeability of from about 450 CFM to about 1000 CFM.

Figures 4A through 4E are photographs of absorbent sheets made using a structured fabric of long warp knuckle projections, such as the characterization of Figures 3A through 3F. In particular, Figures 4A through 4E show the air side of the absorbent sheet, i.e., the side of the absorbent sheet that contacts the structured fabric during the process of forming the absorbent sheet. Thus, the absorbent sheet has a unique shape by contact with the structured fabric, including the protruding regions from which the display side of the absorbent sheet protrudes, as seen in Figures 4A through 4E. It is worth noting that the machine longitudinal direction (MD) of the absorbent sheet is shown vertically in these figures.

Specific features of the absorbent sheet 1000 are illustrated in Figure 5, which is based on the photograph shown in Figure 4E. The absorbent sheet 1000 includes a plurality of substantially rectangular projecting regions, and the outlines of the partial projecting regions are drawn in FIG. 5 and are labeled 1010, 1020, 1030, 1040, 1050, 1060, 1070, and 1080. As explained above, the projecting regions 1010, 1020, 1030, 1040, 1050, 1060, 1070, and 1080 correspond to the web portions of the pockets of the structured fabric during the process of forming the absorbent sheet 1000. The portion of the connection in Figure 5, labeled 1015, 1025, and 1035, forms a network interconnecting the protruding regions. The attachment region generally corresponds to the portion of the web formed in the face of the knuckle projection of the structured fabric during the process of forming the absorbent sheet 1000.

Those of ordinary skill in the art will immediately recognize that the absorbent sheets shown in Figures 4A through 4E and Figure 5 differ from the conventional absorbent sheets in several features. For example, all of the projecting regions include a plurality of indentations forming the top of the projecting region, the indented strips spanning the projecting area of the CD of the absorbent sheet. The outline of a portion of the inner concave strip is drawn in Figure 5 and is labeled 1085. In particular, almost all of the protruding regions have three such concave strips, and the partial protruding regions have four, five, six, seven or even eight concave strips. The number of indentations can be confirmed using laser scanning profiling techniques (described below). Using such laser scanning profiling techniques, it has been found that in a particular absorbent sheet according to an embodiment of our invention, each of the protruding regions has an average of about six indentations.

Without being bound by theory, we believe that the concave strips visible in the absorbent sheets shown in Figures 4A through 4E and 5 are transferred to the structured fabric having the configuration described herein during the papermaking process as described herein. Formed at the time. In particular, when the speed difference is used to cause the web being transferred to the structured fabric to crepe, the web "ploughs" the knuckles of the structured fabric and enters the pocket between the knuckle projections. As a result, a fold is created in the structure of the web, especially in the area of the web that is moved into the pocket of the structured fabric. The inner strip is thus formed between the two folds of the web. Due to the long MD pockets of the structured fabric of the long warp knuckle projections described herein, the plowing/folding effect occurs multiple times across the web portion of the pocket of the structured fabric. Thus, the projecting regions of the absorbent members made of the structured fabric of the long warp knuckle projections described herein each have a plurality of indentations.

Again, without being bound by theory, we believe that the indentations in the protruding regions help to enhance the softness felt by the absorbent sheets according to our invention. In particular, when the absorbent sheet is touched, the inner concave strip provides a smoother, flater, perceived plane than an absorbent sheet having a conventional protruding area. 6A and 6B are diagrams of the absorption sheet 2000 and the comparison sheet 3000 according to our invention, respectively, illustrating the difference in the sensing plane. In the absorbent sheet 2000, the projecting regions 2010 and 2020 include inner concave strips 2080, and ridges are formed between the inner concave strips 2080 (in the papermaking process as described above, the ridges/inner recesses correspond to the folds in the web) ). A small concave strip 2080 and a plurality of ridges surrounding the inner concave strip 2080 are formed, a flat, smooth sensing plane P1 (indicated by dashed lines in Figure 6A). When the absorbent sheet 2000 is touched, these flat, smooth planes P1 are felt. We further believe that the user is unable to perceive a small amount of discontinuity in the indented strip 2080 in the surface of the protruding regions 2010 and 2020, and the user is not aware of the short distance between the protruding regions 2010 and 2020. Therefore, the absorbent sheet 2000 has a smooth, soft surface. On the other hand, because the conventional domes 3010 and 3020 in the comparative sheet 3000 as shown in FIG. 6B, and the conventional domes 3010 and 3020 are separated, the sensing plane P2 has a more rounded shape. Since the sensing planes P2 of the conventional arch tops 3010 and 3020 are separated from each other by a significant distance, compared with the sensing plane P1 found by the protruding regions 2010 and 2020 having the concave strips 2080, it is felt that the comparative sheet 3000 is less smooth and less soft.

Those of ordinary skill in the art will appreciate that each of the protruding regions in the absorbent sheet is not identical due to the nature of the papermaking process. In fact, as described above, the protruding regions of the absorbent sheet according to our invention may have a different number of concave strips. At the same time, the portion of the protruding area observed in any particular absorbent sheet of our invention may not include any internal indentations. However, this will not affect the overall properties of the absorbent sheet as long as the protruding portion of the main portion includes the inner concave strip. Therefore, when we mention that the absorbent sheet has a projecting region including a plurality of inner concave strips, it will be appreciated that the absorbent sheet may have some protruding regions without the inner concave strip.

The length and depth of the indentations in the absorbent sheet, as well as the length of the protruding regions, can be determined by the surface profile of the protruding regions produced using laser scanning techniques well known in the art. Figures 7A and 7B show a laser scanning profile profile across a protruding region in an absorbent sheet according to our invention. The peak of the laser scanning profile profile is the area adjacent the dome of the inner groove, and the valley of the profile profile represents the bottom of the inner bar. Using such a laser scanning profile profile, we have found that the indented strip extends to a depth below the top of the adjacent region of the projecting region by a depth of from about 45 microns to about 160 microns. In a particular embodiment, the indented strip extends to the top of the vicinity of the vicinity of the projecting region to average (take the middle) about 90 microns. In some embodiments, the protruding regions extend a total length of about 2.5 mm to about 3 mm in the machine longitudinal direction (MD) of the substantially absorbent sheet. It will be appreciated by those of ordinary skill in the art that the length of the MD in the projecting region is greater than the length of the projecting region of the conventional fabric, and the long projecting region is at least partially structured as described above for producing the absorbent sheet. The result of the long MD pocket of the fabric. From the laser scanning profile profile, it can also be seen that in our embodiment of the invention, the indented strips are spaced about 0.5 mm apart along the length of the projecting region.

Further different features that can be seen in Figures 4A through 4E and 5 include that the protruding regions are bilaterally staggered in the MD such that substantially continuous stepped lines of the protruding regions extend in the MD of the absorbent sheet. For example, referring to FIG. 5, the protruding regions 1010 are disposed adjacent to the protruding regions 1020, and the two protruding regions overlap at the regions 1090. Likewise, in region 1095, the protruding region 1020 overlaps the protruding region 1030. The bilaterally staggered projecting regions 1010, 1020, and 1030 substantially follow the machine longitudinal direction (MD) of the absorbent sheet 1000 to form a continuous, stepped line. Other protruding regions form similar continuous, stepped lines in the MD.

We believe that the configuration of the elongated bilaterally staggered projecting regions combined with the indentations across the projecting regions results in an absorbent sheet having a more stable configuration. For example, a bilaterally staggered projecting region provides a smoother, flatter surface on the Yankee side of the absorbent sheet, which thus results in a better distribution of the pressure points on the absorbent sheet. It is to be noted that the Yankee side of the absorbent sheet is the side of the absorbent sheet opposite to the air side of the absorbent sheet that is drawn into the structured fabric during the paper making process. In fact, the bilaterally staggered projecting regions act like long plates in the MD direction, allowing the absorbent sheet structure to be placed flat. The combination of the bilaterally interleaved projections and the indentations will, for example, allow the web to be better placed on the surface of the Yankee dryer during the papermaking process, resulting in a better absorbent sheet.

Similar to the continuous line of the protruding regions, the substantially continuous line of the joined regions extends in a stepwise manner along the machine longitudinal direction (MD) of the absorbent sheet 1000. For example, the connection area 1015 that runs substantially in the CD direction is adjacent to the connection area 1025 that runs substantially in the CD direction. The connection region 1025 also abuts the connection region 1035 that runs substantially in the MD direction. Similarly, the connection area 1015 is adjacent to the connection area 1025 and the connection area 1055. In summary, the MD connection area is substantially longer than the CD connection area so that a line of stepped, continuous connection areas can be seen along the absorbent sheet.

As discussed above, the size of the protruding regions and the attachment regions of the absorbent sheet generally correspond to the dimensions of the pockets and knuckles of the structured fabric used to make the absorbent sheet. In this regard, we believe that the relative size control of the projecting area and the joining area contributes to the softness of the absorbent sheet made of fabric. We also believe that the softness is further improved as a result of the substantial continuous lines of the protruding regions and the joined regions. In a particular embodiment of our invention, the distance between the CD across the protruding region is about 1.0 mm, and the distance between the CD across the connecting region oriented at the MD is about 0.5 mm. Furthermore, the length of the overlap/touch area edge MD between adjacent projecting regions of the substantially continuous line is about 1.0 mm. Such dimensions can be determined by visual inspection of the absorbent sheet or by a laser scanning profile profile as described above. When these dimensions are combined with other features of our invention described herein, an exceptionally soft absorbent sheet can be achieved.

In order to evaluate the properties of the article according to our invention, an absorbent sheet was produced using the fabric 15 as shown in Fig. 3E in a papermaking machine having the general configuration shown in Fig. 1 by the process as described above. For comparison, the fabric 17 of the knuckle-like projections also shown in the shorter warp length of Figure 3F was fabricated under the same process conditions. The parameters of the substrate sheets used to make these tests are shown in Table 1. Table 1

The substrate sheet was converted to produce a two-layer adhesive tissue prototype. Table 2 shows the conversion specifications for the test. Table 2

It was found that the sheet formed by the fabric 15 in the test (i.e., the fabric of the long warp knuckle projection) was smoother than the sheet formed by the fabric 17 in the test (i.e., the fabric of the shorter warp knuckle projection). And it is softer. It has been found that other important properties of the sheet made using the fabric 15, such as thickness and volume, can absolutely match the properties of the sheet produced using the fabric 17. Thus, it is clearly contemplated that a substrate sheet made from a fabric 15 of long warp knuckle protrusions can be used to make an absorbent article that is softer than an absorbent article made from a fabric 17 that utilizes a shorter warp knuckle protrusion without reducing Other important properties of absorbent articles.

As described in the fabric characterization publication above, the Plane Volume Index (PVI) is a useful parameter for characterizing structured fabrics. The PVI of a structured fabric is calculated by multiplying the contact area ratio (CAR) by the effective pocket volume index (EPV) multiplied by one hundred, where EPV is the pocket area estimate (PA) and the measured pocket depth. The product of. The depth of the pocket is determined by measuring the thickness of the handsheet formed on the structured fabric in the laboratory and then correlating the measured thickness to the depth of the pocket. Therefore, all PVI related parameters described herein are determined using this handsheet thickness measurement method unless otherwise indicated. Furthermore, the non-rectangular parallelogram PVI is calculated by multiplying the contact area ratio (CAR) by the effective pocket volume index (EPV) multiplied by one hundred, where CAR and EPV are non-rectangular parallelogram unit cell areas. Calculation method to calculate. In an embodiment of our invention, the contact area of the fabric of the structured long warp knuckle projection is varied from about 25% to about 35%, and the depth of the pocket is from about 100 microns to about 600 microns. The change between them, whereby the PVI changes.

Another useful parameter for a characteristic structured fabric associated with PVI is the Planar Bulk Density Index (PVDI) of the structured fabric. The PVDI of a structured fabric is defined as the PVI multiplied by the pocket density. It is worth noting that in our embodiment of the invention, the pocket density varies between about 10 cm ^-2 and about 47 cm ^-2 . The useful parameters of another structured fabric can be developed by multiplying the PVDI by the ratio of the length to the width of the knuckle protrusion of the fabric, thereby providing a PVDI-knuckle protrusion ratio (PVDI-KR). For example, the PVDI-KR of a structured fabric of long warp knuckle protrusions as described herein is the width of the PVDI of the structured fabric multiplied by the length of the MD warp knuckle projection relative to the width of the CD warp knuckle projection. proportion. It is apparent from the variables used to calculate PVDI and PVDI-KR that these parameters take into account important aspects of the structured fabric (including percentage of contact area, pocket density and pocket depth), which are affected by the use of structured fabrics. The shape of the paper product, and therefore, PVDI and PVDI-KR can be used as indicators of the properties of paper products such as softness and absorbency.

The PVI, PVDI, PVDI-KR and other characteristics of the three long warp knuckle protrusions of the structured fabric according to the embodiment of our invention were determined and the results are shown in Figs. 8 to 18 in Figs. For comparison, the PVI, PVDI, PVDI-KR and other characteristics of the structured fabric of the shorter warp knuckle projections were also determined, as shown by fabric 21 in FIG. In particular, the fabrics 18-20 have a PVDI-KR of from about 43 to about 50, which is significantly greater than the PVDI-KR of 16.7 of the fabric 21.

The fabrics 18-21 were used to make an absorbent sheet, and the characteristics of the absorbent sheet were measured as shown in FIG. The characteristics shown in Figure 9 were determined using the same techniques as described in the aforementioned fabric characterization patent. In this aspect, the measurement of the interconnected regions corresponds to the warp knuckle projections on the structured fabric, and the projecting regions correspond to the pockets of the structured fabric. Again, it can be seen again that the panels made of fabric 18-20 of long warp knuckle projections have a plurality of indentations in each of the projection regions. On the other hand, the projecting region of the absorbent sheet formed by the fabric 21 of the shorter warp knuckle projection has at most one inner concave strip, and many of the protruding regions have no concave inner strip at all.

The sensory softness of the absorbent sheet shown in Fig. 9 was measured. Sensory softness is a measure of the perceived softness of a paper product as determined by trained reviewers using standardized testing techniques. More specifically, sensory softness is measured by appraisers with softness measurement experience, in which the reviewer follows a particular technique for grabbing paper and determining the perceived softness of the paper. The higher the sensory softness value, the higher the perceived softness. In the examples of the sheets manufactured from the fabrics 18 to 20, it was found that the absorbent sheets produced from the fabrics 18 to 20 were softer than the absorbent sheets manufactured from the fabric 21 by 0.2 to 0.3 degrees of softness. This difference is significant. Furthermore, it was found that the sensory softness is related to the PVDI-KR of the fabric. In other words, the higher the PVDI-KR of the structured fabric, the higher the sensory softness value achieved. Therefore, we believe that PVDI-KR is a good indicator of the softness achievable with paper products made by the method of structured fabrics. The higher the PVDI-KR of the structured fabric, the softer the manufactured product.

Figures 10A through 10D show the characteristics of the fabrics 22 to 41 of other long warp knuckle protrusions according to different embodiments of our invention, including PVI, PVDI and PVDI-KR for each fabric. It is worth noting that these structured fabrics have a much broader range of properties than the structured fabrics described above. For example, the warp knuckles of the fabrics 22 to 41 have a contact length ranging from about 2.2 mm to about 5.6 mm. However, in other embodiments of our invention, the warp knuckle protrusions may have a contact length ranging from about 2.2 mm to about 7.5 mm. It is worth noting that in the examples of fabrics 22 to 37 and 41, by forming handsheets on the fabric, and then measuring the size of the top of the arch on the handsheet (such as the size of the dome of the corresponding pocket size described above) The depth of the pocket was measured. The depth of the pockets of the fabrics 38 to 40 was determined using the techniques described in the aforementioned fabric characterization patents.

Other tests were conducted to evaluate the properties of the absorbent sheets according to the examples of our invention. In these tests, fabrics 27 and 38 were used. In these tests, a paper machine having a general configuration as shown in Fig. 1 was used in the above process. The parameters used to make the substrate sheets for these tests are shown in Table 3. It is worth noting that the expression of rate of change means that the process variables change as different tests are performed. Table 3 The substrate sheets in these tests were converted to unprinted, single layer rolls.

Photographs of absorbent sheets made from fabric 27 are shown in Figures 11A through 11E, and photographs of absorbent sheets made using fabric 38 are shown in Figures 12A through 12E. As is apparent from Figs. 11A to 11E and Figs. 12A to 12E, the projecting region including the absorbent sheet includes a plurality of inner concave strips similar to the above absorbent sheet. Further, similar to the above-described absorbent sheet, the absorbent sheet made of the fabrics 27 and 38 includes bilaterally staggered projecting regions, resulting in a substantially continuous machine direction (MD) of the absorbent sheet, a stepped line, and between the projecting regions. Substantially continuous, stepped connection areas.

The outline of the projecting region of the substrate sheet made of the fabrics 27 and 38 was measured by the same method as described above for measuring the profile of the absorbent sheet. It was found that the projecting region of the base sheet manufactured from the fabric 27 had 4 to 7 inner concave strips, each of which had an average of 5.2 inner concave strips. The inner strip of the projecting region extends to a position below the top of the vicinity of the projecting region by about 132 to about 274 microns and the average (intermediate) depth is about 190 microns. Furthermore, the projecting area extends about 4.5 mm in the MD of the substrate sheet.

The projecting area of the base sheet made of the fabric 38 has 4 to 8 inner concave strips, each of which has an average of 6.29 inner concave strips. The inner recess of the projecting region of the base sheet made of fabric 38 extends to a lower portion of the vicinity of the vicinity of the projecting region by about 46 to about 159 microns and has an average (intermediate) depth of about 88 microns. Furthermore, the protruding region extends about 3 mm in the MD of the substrate sheet.

Since the extended MD-direction projections of the substrate sheets made from fabrics 27 and 38 comprise a plurality of indentations, the presumed substrate will have advantageous properties similar to those of the absorbent regions described above. For example, the base sheets made from fabrics 27 and 38 are softer to touch than the base sheets made from fabrics that do not have long warp knuckle protrusions.

Other properties of the substrate sheet made from fabrics 27 and 38 are compared to the properties of a substrate sheet made from a fabric of shorter knuckle protrusions. In particular, the thickness of the uncalendered base sheet made from different fabrics and the depth of the pocket are compared. The thickness is measured using standard techniques well known in the art. The thickness of the base sheet made from fabric 27 was found to be from about 80 mils/8 pieces to about 110 mils/8 pieces, while the base sheets made from fabric 38 were from about 80 mils/8 pieces to about 90 mils/ 8 pieces vary. These two thickness ranges are absolutely matchable even if there is no thickness of about 60 to about 93 mils/8 pieces of the substrate sheet made of a fabric of shorter warp knuckle protrusions under similar process conditions.

The depth of the projecting area is measured by a topographical profile scan of the air side of the substrate sheet (i.e., the side of the substrate sheet that contacts the structured fabric during papermaking) to determine the underside of the Yankee side surface The depth of the lowest point of the protruding area. The depth of the protruding regions of the substrate sheet made using the fabric 27 ranges from about 500 microns to about 675 microns, while the depth of the protruding regions of the substrate sheet made using the fabric 38 ranges from about 400 microns to about 475 microns. The depth of these protruding regions is matched even if there is no depth greater than that of a structured fabric made of a structured fabric having a shorter warp knuckle-like projection. The comparability of the depth of the projecting region is consistent with the finding that the substrate sheet made of the structured fabric of long warp yarns has a thickness comparable to that of a structured fabric made of a structured fabric of shorter warp yarns, so the depth of the projecting region It is directly related to the thickness of the absorbent sheet.

The characteristics of the fabric of the other long warp knuckle protrusions according to our invention are indicated in Fig. 13 by the fabrics 42 to 44. A conventional fabric 45 that does not include long warp knuckle projections is also shown in FIG. Other characteristics of fabric 42 are provided in Figure 14, which shows a profile distribution along one of the warp yarns of the fabric. As shown in the figures, the fabric 42 has several salient features in addition to the long warp knuckle projections. One feature is that the pocket is long and deep, as reflected by the PVI related parameters as indicated in FIG. In the embossed photograph of the fabric 42 shown in Fig. 13, it can also be seen that another distinguishing feature of the fabric is that the CD yarns are all located below the knuckle-like projection plane of the MD yarn so that there is no CD finger on the top surface of the fabric. Jagged protrusions. Since there is no CD knuckle protrusion, there is a gentle slope relative to the warp yarn in the z direction, the details of which are shown in the contour profile scan in Fig. 14. As indicated by this figure, the warp yarn has a slope of about 200 mm/mm from the lowest point through which the warp yarn passes under the CD yarn to the top of the adjacent warp knuckle protrusion. More generally, the warp yarns and fabric 42 are moved at an angle of about 11 degrees during the creping operation. We believe that the gentle slope of the warp yarns allows the fibers of the web to be pressed into the fabric 42 and only slightly accumulate in the inclined portions of the warp yarns before some of the fibers fall onto the top of the adjacent knuckle projections. The gentle slope of the warp yarns in the fabric 42 thus produces less steep stops of the web fibers and less fiber densification than other fabrics having warp yarns that have a steep slope that contacts the web.

Both fabrics 42 and 43 have higher PVDI-KR values and these values, along with the PVDI-KR values of other structured fabrics described herein, are a general characterization of the PVDI-KR values that can be found in our embodiments of the invention. Further, structured fabrics having higher PVDI-KR values can also be used, for example up to about 250.

To evaluate the properties of the fabric 42, a series of tests were performed on the fabric and the fabric 45 for comparison. In these tests, a paper machine having a general configuration as shown in Fig. 1 was used to form a water-absorbent tissue base sheet. The use is generally described above (and in particular the non-TAD process described in the '563 patent above), wherein the web is dewatered when transferred to the top of the structured fabric (i.e., fabric 42 or 45) in the creping nip. To a consistency of about 40 to about 43 percent. Other special parameters for these tests are shown in Table 4. Table 4

The properties of the substrate sheets made using fabrics 42 and 45 in these tests are shown in Tables 5 through 9. Test procedures for determining these properties, as shown in Tables 5 through 9, can be found in U.S. Patent Nos. 7,399,378 and 8,409,404, the disclosures of each of each of each of The expression "N/C" indicates that this property was not calculated in a particular experiment. table 5 Table 6 Table 7 Table 8 Table 9

The test results shown in Tables 5 through 9 demonstrate that the fabric 42 can be used to make a substrate sheet having a combination of outstanding properties such as thickness and absorbency. Without being bound by theory, we believe that these results are derived in part from the construction of the knuckles and the pockets of the fabric 42. In particular, due to the aspect ratio of the pocket (i.e., the length of the pocket at the MD relative to the width of the pocket at the CD), the construction of the fabric 42 provides a highly efficient creping operation, the pocket is deep and The pockets form a long, nearly continuous line in the MD. These pocket properties allow for greater fiber "movability" which is a condition for the wet compression web to withstand the mechanical forces of local basis weight movement. Furthermore, during creping, the cellulosic fibers in the web are subjected to different local forces (e.g., thrust, tensile, bending, delamination forces) and then become further apart from each other. In other words, the fibers become loose and result in a lower modulus of the article. Therefore, the web has a better vacuum "moldability" which results in a larger thickness and a more loose structure which provides greater absorption.

The fiber mobility provided by the pocket configuration of the fabric 42 can be seen by the results shown in Figures 15 and 16. These figures compare the thickness, saturation (SAT) capacity, and void volume at various degrees of origin used in the test. Figures 15 and 16 show that even in the test using the fabric 42, without vacuum forming, the thickness and saturation (SAT) capacity increased as the fabric creping increased. Because there is no vacuum forming here, the thickness and saturation (SAT) capacity of the fabric 42 is necessarily directly related to fiber mobility. In the test using vacuum forming, the thickness and saturation (SAT) capacity of the base sheet produced from the fiber 42 were far greater than the thickness and saturation (SAT) capacity of the base sheet manufactured from the fabric 45 in each degree of twist. Figures 15 and 16 also demonstrate that a high amount of thickness and saturation (SAT) capacity can be achieved using the fabric 42.

In the results shown in Figures 15 and 16, the fiber moldability provided by the fabric 42 can also be seen. In particular, the difference between the thickness and saturation (SAT) capacity of the test without vacuum forming and the vacuum formed test confirmed that the fibers in the web were highly formable on the fabric 42. As will be discussed below, the fibers formed in the region of the web of the pockets of the fabric 42 are drawn by vacuum forming. High fiber moldability means that a large amount of fiber is drawn out during the forming operation, which results in an increase in the thickness and saturation (SAT) capacity of the resulting article.

Figure 19 also demonstrates the use of fabric 42 to achieve greater fiber mobility by comparing the void volume of the substrate sheet in the test for the degree of fabric creping. The absorbency of the sheet is directly related to the void volume, which is primarily a measure of the space between the cellulose fibers. The void volume is measured by the procedure described in the above-mentioned U.S. Patent No. 7,399,378. As shown in Fig. 19, the void volume increases as the fabric crepe of the test using the fabric 42 increases, wherein vacuum forming is not used. This indicates that at each fabric crepe, the cellulosic fibers are further separated from one another (i.e., loosened, with a lower resulting modulus) so that additional void volume can be created. Figure 19 further demonstrates that when vacuum forming is used, the fabric 42 produces an absorbent sheet having a larger void volume than the conventional fabric 45 at the level of creping of each fabric.

20A, 20B, 21A and 21B also show the fiber mobility when the fabric 42 is used, which is a soft X-ray image of the base sheet using the fabric 42. As is well known to those of ordinary skill in the art, soft X-ray imaging is a high resolution technique that can be used to measure the quality uniformity of paper. The base sheet of Figs. 20A and 20B in which 8 percent of the fabric crepe is formed, and the base sheet of Figs. 21A and 21B is made into a 25 percent fabric crepe. Figures 20A and 21B show the extent to which the fiber moves at a "maize view" and the image shows an area of 26.5 mm times 21.2 mm. A higher fabric crepe can be seen with fewer clumps of wavy patterns (corresponding to higher areas in the image) (Fig. 21A), but with lower fabric creases, it is not easy to see areas with fewer clumps (figure 20A). Figures 20B and 21B show a more "microscopic" degree of fiber movement with an image display area of 13.2 mm by 10.6 mm. It can be clearly seen that the higher fabric creping (Fig. 21A) allows the cellulosic fibers to be spaced further apart and pulled apart than the lower fabric creping (Fig. 20B). Intensively, the soft X-ray image further confirms that for higher local agglomerates, the fabric 42 provides higher fiber mobility, and it can be seen that the higher fabric crepe is higher than the lower fabric crepe.

Figures 17 and 18 and Figure 19 show the results of the tests in terms of ingredients. In particular, these figures show that when using non-prepared ingredients and premium ingredients, the fabric 42 is capable of producing a matchable thickness, saturation (SAT) capacity, and void volume. This is a very advantageous result as it demonstrates that the fabric 42 can achieve outstanding results with low cost and non-quality ingredients.

Because fabric 42 has extra long warp knuckle projections, as with other fabrics having extra long warp knuckle projections, articles made from fabric 42 may have a plurality of indentations extending in the CD direction. The inner strip again serves as a result of the folding of the web region that is moved into the pocket of the structured fabric. In the example of fabric 42, we believe that the length of the knuckle projections and the aspect ratio across the length of the pockets further enhance the formation of the fold/recess strip. This is because the web is semi-constrained in the long warp knuckle projections and more movable in the pockets of the fabric 42. The result is that the web can be fastened or folded along each pocket, which in turn results in a visible CD in the article.

The formation of a concave strip in the absorbent sheet made of the fabric 42 can be seen in Figures 22A to 22E. These figures are images of the air side of the article made from fabric 42 at different fabric crepe levels, but without vacuum forming. MD is the vertical direction in all figures. In particular, instead of a well-defined projecting region having an article similar to that described above, the article of Figures 22A through 22E is characterized by a parallel and approximately continuous line of protrusions extending substantially in the MD direction, each extending projection The region includes a plurality of indentations in the substantial CD across the projecting region of the absorbent sheet. These protruding regions correspond to the lines of the pockets of the MD extension of the fabric 42. Between the projecting regions is a connecting region which is also substantially extended in the MD. The attachment region corresponds to the long warp knuckle projection of the fabric 42.

The article of Figure 22A was made using 25% fabric crepe. In this product, the inner concave strip is very noticeable. We believe that the pattern of the indented strip is the result of a fiber network on the fabric 42 that undergoes a wide range of forces including in-plane compression, tension, bending and fastening during creping. All of these forces will contribute to fiber mobility and fiber moldability as discussed above. Moreover, as a result of the approximately continuous nature of the overhanging regions of the MD extension, enhanced fiber mobility and fiber moldability occur along the MD in an approximately continuous manner.

Figures 22B through 22E show the article construction having a lower fabric crepe than the article shown in Figure 22A. In Fig. 22B, the fabric used to form the article has a crepe degree of 15%, in Fig. 22C, the fabric crepe degree is 10%, in Fig. 22D, the fabric crepe degree is 8%, and in Fig. 22E The fabric has a creping degree of 3%. As can be expected, it can be seen that the extent of the fold/recess strip decreases as the degree of fabric creping decreases. However, it is worth noting that the frequency of the inner strip remains the same between the degree of fabric creping. This indicates that the web is fastened/folded at the same position relative to the knuckle projections and pockets of the fabric 42 regardless of the degree of creping of the fabric used. Thus, even at lower fabric creping levels, advantageous properties derived from the formation of the folded/recessed strips can be found.

In summary, Figures 22A through 22E show that the high pocket-like aspect ratio of the fabric 42 has the ability to uniformly impart loose energy to the web, enabling fiber mobility and fiber moldability to be promoted over a wide fabric crepe range. Furthermore, fiber mobility and fiber moldability are very important factors for outstanding properties such as thickness and saturation (SAT) capacity found in absorbent sheets made from fabric 42.

23A through 24B are scanning electron microscope images (Figs. 23A and 24B) on the air side of articles made using fabric 42, and comparative articles (Figs. 23B and 24B) made using fabric 45. In these examples, the product was made using 30% fabric crepe and maximum vacuum forming. The central regions of the image in Figures 23A and 23B show the regions formed in the pockets of the individual fabrics with regions surrounding the central regions corresponding to the knuckled projections formed on the individual fabrics. Figures 24A and 24B show a section extending substantially along the MD, having a raised region of the extension of the fabric 42 visible in Figure 24A, and a plurality of arch tops visible in the fabric 45 article shown in Figure 24B (as formed in the majority) Bag-shaped part). It is very clear that the fiber buildup in articles made from fabric 42 is less dense than cellulose fibers in articles made using fabric 45. In other words, the central projecting area in the fabric 45 article is highly dense, and in terms of density, even if it is not very dense, it is denser than the joint area of the pocket portion of the article surrounding the fabric 42. Further, Figures 24A and 24B show that the fibers of the article of fabric 42 are relatively loose, i.e., less dense, than the article of fabric 45, with individual fibers that have emerged from the fabric 42 product shown in Figure 24A. Figures 23A through 24B thus further confirm that the fabric 42 provides a large amount of fiber mobility and fiber moldability in the creping process, and then in the absorbent sheet article made from the fabric, results in areas where the density is significantly reduced. The reduced density region provides greater absorbency in the article. Furthermore, the area of reduced density provides a greater thickness as the sheet becomes more "bulk" in the reduced density region. Also, a bulky, less dense area will result in the article feeling softer to the touch.

Other tests were conducted using fabric 42 to evaluate the properties of the tissue articles transformed according to the examples of our invention. For these tests, the same conditions as those described in conjunction with Tables 4 and 5 were used. The substrate piece is then converted into a two layer paper towel. Table 10 shows the conversion specifications for these tests. The properties of the articles made in these tests are shown in Tables 11 to 13. Table 10 Table 11 Table 12 Table 13

It is worth noting that the test 22 only formed a single layer product, but other transformations could be carried out in the same manner as other tests.

The results shown in Tables 11 to 13 demonstrate the superior properties that can be achieved with fabrics using the long warp knuckle projections according to our invention. For example, the final article made with fabric 42 has a greater thickness and a higher saturation (SAT) capacity than a comparative article made using fabric 45. Furthermore, the results of Tables 11 through 13 demonstrate that the fabric 42 can be used to make very comparable articles, whether using premium ingredients or non-premium ingredients.

In accordance with the nature of the articles made in the tests described herein, it is clear that the structured fabrics of the long warp knuckles described herein can be used to provide a method of forming articles having a combination of outstanding properties. For example, the structured fabric of the long warp yarn knuckle protrusions described herein can be combined with the non-TAD process described above in the '563 patent (where the papermaking ingredients are compacted prior to creping), as generally described and explicitly described above. Together, it is used to form an absorbent sheet having a SAT capacity of at least about 9.5 g/g and at least about 500 g/m ² . Further, the absorbent sheet can be formed by this method while using a creping ratio of less than about 25%. Moreover, the method and structured fabric of long warp knuckle protrusions can be used to make absorbent sheets having a SAT capacity of at least about 10.0 g/g and at least about 500 g/m ² and less than about 30 lbs/ The basis weight, and the density of 220 mils / 8 pieces. We believe that this type of method has never produced such an absorbent sheet before.

Other absorbent paper towel base sheets were made using fabrics 42 and 45 in the test. These tests were carried out using a non-TAD process substantially as described above (and in particular described in the '563 patent above) on a paper machine having the structure shown in Figure 1, and the parameters of these tests are shown and described in Table 4 above. The parameters of the test are the same. The results of these tests are shown in Tables 14 to 16 below. Table 14 Table 15 Table 16

As previously described, the absorbent sheets made using fabric 42 in the tests shown in Tables 14 through 16 have outstanding combinations of characteristics, particularly outstanding thickness and absorbency.

Figures 25A and 25B illustrate the characteristics of other structured fabrics in accordance with our invention. Similar to the fabric discussed above, the fabrics 46-52 shown in Figures 25A and 25B have long warp knuckle projections ranging from about 2.4 mm to about 5.7 mm. Also similar to the fabrics discussed above, fabrics 46-52 have high PVDI-KR values ranging from about 41 to about 123.

Fabrics 46 to 52 also demonstrate another aspect of our invention relating to the positioning of the knuckle projections on the surface of the structured fabric contacting the web. As shown in the embossed photograph, the knuckled projections in the fabrics 46 to 52 are positioned relative to each other such that a straight line passing through the center of the majority of the knuckle projections can be drawn. One such line L1 is shown in Figure 26, which is a detailed view of the embossed structure of the fabric 50. The angle α of the straight line L1 with respect to the straight line MDL extending in the machine direction (MD) of the fabric is about 15°. In other structured fabrics according to our invention, the straight line of the warp knuckle protrusions is about 10° to about 30° with respect to the longitudinal direction of the machine (MD), and in a more specific embodiment, the warp fingers The knot-like protrusions are linearly spaced from about 10° to about 20° with respect to the machine longitudinal direction (MD). The angle of the warp yarns of the fabrics 46 to 52, which are straight lines, is provided in Figures 25A and 25B. It should be noted that some of the other fabrics described herein include oblique straight lines of similar warp knuckle projections, such as fabric 42 shown in FIG.

We have found that paper products made from structured fabrics having straight lines of beveled warp knuckle projections such as fabrics 42 and 46 to 52 have superior properties. Without being bound by theory, it is believed that these superior properties result from the large amount of fiber mobility provided by the structured fabric having straight lines of beveled warp knuckle protrusions.

Figure 27A demonstrates the fiber mobility of a structured fabric having straight lines of beveled warp knuckle protrusions, and this fiber mobility can be compared to other structured fabric structures as shown in Figures 27B and 27C. The fibers move to the folded configurations 4002 and 5002 shown in these figures, such as during the creping operation, such as when the web 116 is transferred by the pressure roller 108 to the structured fabric 112 in the creping nip 120, as shown in FIG. Shown and as above. Figure 27B illustrates an example of a machine longitudinal (MD) knuckle protrusion 4000 in a structured fabric. During the creping process, the cellulosic fibers of the web are stacked into a compact folded configuration 4002 that is pressed against the edge 4004 of the knuckle protrusion 4000, thereby creating a local densification zone 4006 adjacent the knuckle protrusion 4000. Local densification of this fiber also occurs in other machine longitudinal (MD) knuckles of the structured fabric. Figure 27C shows how the machine direction (machine direction (CD)) knuckle protrusion 5000 of the structured fabric also has a local densification zone which is the result of the web fold 5002 stacking against the edge 5004 of the knuckle protrusion 5000. .

In contrast, the knuckle protrusion 6000 of the oblique warp yarn line shown in Fig. 27A causes a folded configuration which is more different from the folding structure illustrated in Figs. 27B and 27C. Using the oblique warp yarn knuckle projection straight line, a strain field is created by the movement of the knuckle projection 6000 and the adhesion of the web 116 to the pressure roller 108. The strain field is localized to a pocket that is bounded by the knuckle protrusions 6000. Due to the creping ratio, the strain field causes a difference in the speed at which the web is transferred from the transfer surface to the structured fabric in the creping nip: in the creping nip, a portion of the web is pulled in the downstream direction by moving the faster transfer surface Stretching, while other portions of the web are efficiently supported by the slower moving knuckle projections 6000. During the creping operation, the web has, for example, 40% to 45% solids, which means that the web has substantially viscous properties. Thus, the fibers of the web in the strain field can be permanently positioned relative to each other after leaving the creping operation, and the fibers do not return to their relative position prior to entering the strain field. Fiber mobility in the strain field increases the fiber-fiber distance and thus weakens the bond between the fibers, so the web can be more mold molded. The result is that the fibers are distributed in the curved folds of the pocket between the knuckle protrusions 6000. The curved fold is an indicator of the fiber movement behavior that has occurred in the pocket. Furthermore, the results as described in the above test can show that there is a significant improvement in absorbency and softness when fiber folding is caused to cause bending, such as SAT and voids of the absorbent sheet made of fabric 42. The volume can be confirmed.

The curved fold is shaped such that the curved apex 6003 is positioned downstream of the machine longitudinal direction (machine longitudinal direction (MD)) and the curved folded end is offset from the machine longitudinal direction (MD), the curved folded end 6007 relative to the bend The other end of the fold 6009 is positioned upstream of the machine longitudinal direction (MD). In comparison, in a structured fabric having no straight line of oblique warp yarns as shown in Figures 27B and 27C, the fiber stack formed at the edges of the knuckle protrusions in the machine direction (MD) and the machine direction (CD) is compared. The curved fold shown in Figure 27A is significantly looser. Furthermore, we believe that the absorbent sheet has significantly improved softness and absorbency due to the lower densification of the curved fold, which is then related to the fiber mobility discussed above.

The curved folded shape is also related to the distance D1 between the knuckle protrusions 6000. It will be appreciated by those of ordinary skill in the art that if the knuckle-like projections 6000 are too tight, there is insufficient space in the pockets between the knuckle-like projections 6000 for the fibers to move into the looser, curved folds. . On the other hand, if the knuckle-like protrusions are too far apart, many of the fibers will not be able to be affected by the faster moving transfer surface and the strain field of the more rapidly moving knuckle-like protrusions, and thus in the fiber web and thus in the resulting In the absorbent sheet, it is possible to form a less less pronounced curved fold. Based on such considerations, in our embodiment of the invention, the distance D1 between two adjacent knuckle protrusions 6000 in the different warp knuckle protrusion lines may be from about 1.5 mm to about 4.0 mm. In a particular embodiment, the distance D1 is about 2.0 mm. The distance between the knuckle protrusions 6000 is 2.0 mm, and the pocket region between the two adjacent knuckle protrusions 6000 has a space of about 1.5 mm.

28A to 28E are photographs of an absorbent substrate sheet which is a structured fabric having a straight line of oblique angle warp knuckle protrusions, using a paper machine having the general configuration shown in Fig. 1, substantially as described above (and especially The non-TAD process described in the '563 patent above is made using the parameters shown in Table 4 above. The base sheets shown in Figures 28A through 28E each use a different creping ratio (i.e., fabric crepe %). In particular, the base sheet of Fig. 28A is manufactured using a mold opening degree of 25% and a mold vacuum of 2 in. Hg, and the base sheet of Fig. 28B is a mold box vacuum using a 25% crepe ratio and 8 in. Hg. The base sheet of Fig. 28C is manufactured by using a 30% crepe ratio and a mold vacuum of 10 in. Hg, and the base sheet of Fig. 28D is a mold box using a 25% crepe ratio and 8 in. Hg. Vacuum degree is manufactured. The substrate sheet shown in Fig. 28E was fabricated using a 20% crepe ratio but no mold box vacuum. It is to be noted that, in the manufacture of the substrate sheet shown in Fig. 28E, no vacuum molding was used, but the substrate sheet still exhibited the structure of the web which followed the creping operation during the paper making process. In other words, the web in the papermaking process will have the same generally curved folded configuration as the base sheet product shown in Figure 28E. It should also be noted that in other embodiments of our invention, different creping ratios may be used with structured fabrics having straight lines of beveled warp knuckle projections. In some embodiments, the creping ratio used with the beveled warp knuckle tab linear fabric ranges from about 3% to about 100%, and in a more particular embodiment, the crepe ratio ranges from about 3% to About 50%, in yet a more specific embodiment, the crepe ratio is between about 5% and 30%.

The curved fold can be clearly seen in the projecting area of the base sheet shown in Figs. 28A to 28E. In these figures, the machine longitudinal direction (MD) of the sheet is in the vertical direction (i.e., the up and down direction), the upstream side of the sheet is at the top of the photograph and the downstream side of the sheet is at the bottom of the pattern. In Figure 28A, the partially curved fold has been marked with a dashed line. Since the beveled warp knuckle is straight, the end of the curved shape is asymmetrical: one end of the curved fold is positioned further downstream than the other end of the curved fold. The curved fold extends between the ends to the apex of the most downstream portion of the curved fold. Again, the curved folded ends are the attachment regions that are positioned adjacent the knuckle projections of the corresponding fabric.

Curved folds are also seen in the absorbent sheets shown in Figures 22A and 22E. As previously noted, the absorbent sheets in these figures are formed using a fabric 42 that includes beveled straight lines of warp knuckle projections. Furthermore, the curved fold can be seen in the soft X-ray image shown in Figures 21A and 21B.

Figures 28A-28E also show the majority of the curved folds formed in each of the protruding regions. The majority of the curved folds are the result of the length extension in the machine direction (MD) of the pocket, in which the dome region is formed, and thus the curved fold is also related to the length of the warp knuckle projection. When the web is transferred to the structured fabric in a process for making absorbent sheets using a creping operation (as discussed above), most of the folds are created in the web structure within the pockets. Therefore, in the same manner as the above-discussed embodiment, a plurality of inner concave strips are formed in each of the protruding regions of the absorbent sheet, and a plurality of inner concave strips are formed in the protruding regions of the absorbent sheets shown in Figs. 28A to 28E. Most of the curved folds between. This inner concave strip can be seen between the curved folds in the protruding regions of the absorbent sheets shown in Figures 28A through 28E.

In the photographs of the absorbent sheets shown in Figs. 28A to 28E, it is also seen that the joined regions are joined to have projecting regions having curved folds. These connection areas mostly correspond to the sheet portions formed on the knuckle-like projections of the fabric used to manufacture the sheets, and the sheet portions formed in the regions adjacent to the knuckle-like projections and the pockets. The configuration of the joint region of the substrate sheet according to our invention is highlighted in Fig. 28A in which the region adjacent the upstream end portion of the projecting region is circled. It can be seen that the sheet creates a fold in these looped areas. These folds are formed in the warp yarns due to the slope of the z-direction, and lack the cross-sectional protrusions of the machine direction (CD) as described above. In particular, the web can slide into these portions of the joined area during the paper making process, thereby creating a fold. The folding in the joint region further acts to reduce the density of the fibers, thereby further improving the characteristics of the absorbent sheet.

Based on the photographs shown in Figs. 28A to 28E, the radius of curvature of the curved fold can be calculated. In particular, the circle can be drawn such that the circular arc of the circle is aligned with the curved fold. As is apparent from the photographs shown in Figs. 28A to 28E, the leading edge (downstream) of the curved fold is the most prominent, and thus it is easiest to draw a circle such that the circular arc is aligned with the leading edge. Fig. 29 is the same as the photograph shown in Fig. 28A, but additionally shows a circle having a circular arc aligned with the leading edge of the partially curved fold. From these circles and using the scale of the photograph, the average radius of curvature of the curved fold can be easily calculated. In our inventive embodiment, we have found that the curved folds have an average radius of curvature of about 1.2 mm and a radius ranging from about 0.5 mm to about 2.0 mm.

As discussed above, the curved fold is formed by utilizing a localized strain field created during the creping operation of the beveled warp knuckle projection fabric according to our invention. For a given absorbent sheet, the normalized folding curvature ratio can be calculated by dividing the radius of curvature of the curved fold by the radius of the circle drawn in the projected area. The lower the normalized folding curvature ratio, the more the strain field bends and folds more efficiently. Furthermore, we believe that as the folding curvature is formed more efficiently, the absorbency and softness of the absorbent sheet can be improved.

An example of calculating the normalized folding curvature ratio of the absorbent sheet will now be described with reference to Figs. 30A and 30B. The absorbent sheet according to our invention is shown in Fig. 30A, and a commercially available comparative absorbent sheet is shown in Fig. 30B. In Fig. 30A, an arc corresponding to one of the curved folds has been drawn. From this arc and other similarly drawn arcs, the average radius of curvature of the curved fold can be calculated as discussed above. Similarly, an arc corresponding to the micro-curvature visible by the folded configuration has been drawn in Fig. 30B, and the average radius of the absorptive sheet can thus be calculated from this arc and a similar arc. A complete circle in the projecting region has been drawn in Figures 30A and 30B with rounded opposite points aligned with the points on the opposite side of the protruding region where the curved folded configuration occurs. These circles are the largest dimension that can conform to the extent of the projecting area, and the radius of the circles is thus one-half the distance across the projecting area of the machine direction (CD) of the absorbent sheet. Next, the normalized folding curvature ratio of the absorbent sheet shown in Figs. 30A and 30B can be calculated, which is the ratio of the calculated average radius of curvature to the radius of curvature of the largest circular size in the protruding region. For the absorbent sheet according to our invention shown in Fig. 30A, the calculated average radius of curvature was about 1.2 mm, and the normalized folding curvature ratio was about 1.9. On the other hand, for the comparative absorbent sheet shown in Fig. 30B, the calculated average radius of curvature was about 4.55, and the normalized folding curvature ratio was about 4.5. Thus, it is apparent that the absorbent sheet according to our invention has a higher curvature in the folded configuration than the comparative sheet, and at the same time the curvature is closer to the maximum curvature that is likely to be achieved when forming the absorbent sheet.

In an embodiment of our invention, the normalized fold curvature ratio is less than about 4, and more specifically, from about 0.5 to about 4. In a more particular embodiment, the normalized fold curvature ratio is from about 1 to about 3. As is apparent from the absorbent sheet shown in Fig. 30A, the specific normalized folding curvature ratio of the embodiment of our invention is about 2. When the normalized folding curvature ratio is within these ranges, we believe that a significant amount of fiber mobility can occur for a given fabric. Thus, as discussed above, fiber mobility results in better properties of the paper product, such as good absorbency.

While the invention has been described in terms of a particular exemplary embodiment, many modifications and variations are apparent to those of ordinary skill in the art. Therefore, it is to be understood that the invention may be embodied in other ways other than those which are specifically described. Therefore, the exemplary embodiments of the present invention are intended to be illustrative and not restrictive, and the scope of the invention should be construed as It is decided, not by the foregoing description. Industrial availability

The invention can be used to make desirable paper products such as paper towels or toilet paper. Therefore, the present invention can be applied to the paper product industry.

100‧‧‧Suppressed section
102‧‧‧Paper blankets
104‧‧‧Symmetric steering roller
108‧‧‧pressure roller
112, 300‧‧‧ Structured fabrics
114‧‧‧Vacuum Forming Box
116‧‧‧Fiber
120‧‧‧ starting nip
200‧‧‧ paper machine
202‧‧‧Shaping section
204‧‧‧Headbox
206‧‧‧Forming net
208, 210‧‧‧ Roll
212‧‧‧Forming rolls
214‧‧‧Brubber route
216‧‧‧Support suppression section
217‧‧‧ nip
218‧‧‧Yanke dryer
222‧‧‧ starting scraper
302‧‧‧ warp
304‧‧‧ Weft
306, 310, 4000, 5000, 6000‧‧‧ knuckles
308‧‧‧ bag
1000, 2000 ‧ ‧ absorption tablets
1010, 1020, 1030, 1040, 1050, 1060, 1070, 1080, 2010, 2020 ‧ ‧ protruding areas
1015, 1025, 1035, 1055‧‧‧ Connection area
1085, 2080‧‧‧ concave strip
1090, 1095‧‧‧ area
3000‧‧‧Comparative film
3010, 3020‧‧ ‧ arch top
4002, 5002‧‧‧Folding structure, folding
Edge of 4004, 5004‧‧
4006‧‧‧Local densification zone
Summit of 6003‧‧‧
6007, 6009‧‧‧ end
D1‧‧‧ distance
P1, P2‧‧‧ perception plane

Figure 1 is a schematic view of the structure of a paper machine that can be used in conjunction with our invention.

2 is a top plan view of a structured fabric for making a paper product in accordance with an embodiment of our invention.

Figures 3A through 3F illustrate the characteristics of a structured fabric and the characteristics of a comparative structured fabric in accordance with an embodiment of our invention.

4A through 4E are photographs of an absorbent sheet according to an embodiment of our invention.

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

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

Figures 7A and 7B show laser scanning profiles for determining the profile of the absorbent sheet portion in accordance with an embodiment of our invention.

Figure 8 illustrates the characteristics of a structured fabric and a comparative structured fabric in accordance with an embodiment of our invention.

Figure 9 shows the characteristics of a substrate sheet made using a structured fabric having the characteristics shown in Figure 8.

Figures 10A through 10D illustrate the characteristics of another structured fabric in accordance with an embodiment of our invention.

11A to 11E are photographs of an absorbent sheet of an embodiment of our invention.

Figures 12A through 12E are photographs of other absorbent sheets in accordance with an embodiment of our invention.

Figure 13 illustrates the characteristics of a structured fabric in accordance with an embodiment of our invention and a comparative structured fabric.

Figure 14 shows a profile measurement along one of the warp yarns of a structured fabric in accordance with an embodiment of our invention.

Figure 15 is a table showing the percentage of crepe relative to the thickness of a base sheet made of the fabric according to the embodiment of our invention and the comparative fabric.

Figure 16 is a table showing the percentage of fabric crepe relative to saturation (SAT) capacity of a substrate sheet made using the fabric according to the embodiment of our invention and the comparative fabric.

Figure 17 is a table showing the percentage of fabric crepe relative to thickness of a base sheet made from fabrics of different embodiments according to the embodiments of our invention.

Figure 18 is a table showing the percentage of fabric crepe relative to saturation (SAT) capacity of a substrate sheet made from fabrics of different embodiments according to the embodiments of our invention.

Figure 19 is a table showing the percentage of fabric crepe relative to void volume of a base sheet made using the fabric according to the embodiment of our invention and the comparative fabric.

20A and 20B are soft X-ray images of an absorbent sheet in accordance with an embodiment of our invention.

21A and 21B are soft X-ray images of an absorbent sheet according to another embodiment of our invention.

22A through 22E are photographs of an absorbent sheet according to other embodiments of our invention.

23A and 23B are photographs of an absorbent sheet and a comparative absorbent sheet according to an embodiment of our invention.

24A and 24B are cross-sectional photographs of the absorbent sheets shown in Figs. 23A and 23B, respectively.

Figures 25A and 25B illustrate the characteristics of other structured fabrics in accordance with embodiments of our invention.

Figure 26 is a detailed view of an embossed structure having one of the structured fabrics of the characteristics shown in Figure 25B.

Figures 27A through 27C show the folded configuration of the knuckle projections surrounding the knuckle protrusion of the structured fabric according to our invention and the anatomical fabric of the comparative example.

28A through 28E are photographs of other structured fabrics in accordance with embodiments of our invention.

Figure 29 is a photograph of an absorbent sheet according to an embodiment of our invention having an annotation line for determining the appearance of the fabric.

30A and 30B are photographs of an absorbent sheet and a comparative absorbent sheet according to our invention, respectively.

300‧‧‧Structural fabric

302‧‧‧ warp

304‧‧‧ Weft

306, 310‧‧‧ knuckle-like protrusions

308‧‧‧ bag

Claims (27)

A cellulose absorbent sheet comprising: a plurality of projecting regions projecting from the absorbent sheet, wherein the projecting regions are formed in a fold that is curved relative to a machine longitudinal direction of the absorbent sheet, the curved folded ends Located on opposite sides of the projecting regions, and such that in the machine longitudinal direction of the absorbent sheet, one of each of the curved folded ends is positioned downstream of the other end of the curved fold, and the bends The apex of the fold is positioned longitudinally downstream of the machine of the absorbent sheet; and a joining region connecting the protruding regions of the absorbent sheet. A cellulose absorbent sheet according to claim 1, wherein each of said protruding regions comprises a plurality of said curved folds. The cellulose absorbent sheet of claim 2, further comprising an inner concave strip formed between the curved folds of each of the protruding regions. The cellulose absorbent sheet of claim 1, wherein the curved folds have an average radius of curvature of about 1.2 mm. The cellulose absorbent sheet of claim 1, further comprising a plurality of folds positioned adjacent the ends of the projecting regions located in the longitudinal direction of the machine of the absorbent sheet. A cellulose absorbent sheet comprising: a plurality of projecting regions projecting from the absorbent sheet, wherein the projecting regions are formed in a fold that is curved relative to a machine longitudinal direction of the absorbent sheet, the curved folded ends Located on opposite sides of the projecting regions, the curved folds have a radius of curvature of from about 0.5 mm to about 2.0 mm; and a joining region joining the projecting regions of the absorbent sheet. The cellulose absorbent sheet of claim 6, wherein the curved folds have an average radius of curvature of about 1.2 mm. A cellulosic absorbent sheet according to claim 6 wherein each of said protruding regions comprises a plurality of curved folds. The cellulose absorbent sheet of claim 8, further comprising an inner concave strip formed between the curved folds of each of the protruding regions. The cellulose absorbent sheet of claim 6 further comprising a plurality of folds positioned adjacent the ends of the projecting regions located longitudinally upstream of the machine of the absorbent sheet. A paper web comprising: a plurality of projecting regions projecting from the paper web, wherein the projecting regions are formed in a fold that is curved relative to a machine longitudinal direction of the paper web, the curved folded ends a portion on an opposite side of the projecting regions, and such that in the machine longitudinal direction of the paper web, one of each of the curved folded ends is positioned downstream of the other end of the curved fold, and The apex of the curved fold is positioned longitudinally downstream of the machine of the paper web; and the attachment area connecting the projections of the paper web. A paper web of claim 11 wherein each of said protruding regions comprises a plurality of curved folds. The paper web of claim 12, further comprising an indentation formed between the curved folds of each of the projecting regions. The paper web of claim 12, wherein the folds have a radius of curvature of from about 0.5 mm to about 2.0 mm. A method of making a fabric-creped cellulose absorbent sheet, the method comprising: compressing a papermaking furnish to form a web; under pressure, the web is bounded by a transfer surface Creping with a woven nip between a structured fabric comprising knuckle projections formed on warp yarns of the structured fabric, the knuckle projections being along relative to the fabric The machine is longitudinally oriented in an oblique line, wherein the line is at an angle of from about 10 to about 30 with respect to the machine longitudinal direction of the fabric; and the web is dried to form the cellulose absorbent sheet. The method of claim 15, wherein the creping ratio is defined by the speed of the transfer surface relative to the speed of the structured fabric, and the creping ratio is from about 3% to about 25%. The method of claim 15 wherein the angle of the lines relative to the longitudinal direction of the machine is between about 15°. The method of claim 15, wherein the warp yarns of the structured fabric are inclined downward at a position adjacent to a downstream end of the knuckle-like projections, and the web is folded at a position adjacent to the downwardly inclined portion of the warp yarns. . The method of claim 15 wherein the length of the knuckle projections in the machine longitudinal direction is from about 2.4 mm to about 5.7 mm. The method of claim 15, wherein the plane bulk density index of the structured fabric is multiplied by a ratio of the length of the knuckle protrusion formed on the warp yarn to the width of from about 41 to about 123. A cellulose absorbent sheet produced by the method of claim 15, the cellulose absorbent sheet comprising: a plurality of protruding regions protruding from the absorbent sheet, wherein the protruding regions are formed with respect to the absorbent sheet The machine is longitudinally in a curved fold, the curved folded ends being located on opposite sides of the projecting regions, and the curved apex of the bends being positioned longitudinally downstream of the machine of the absorbent sheet. A cellulose absorbent sheet comprising: a plurality of projecting regions projecting from the absorbent sheet, wherein the projecting regions are formed in a fold that is curved relative to a machine longitudinal direction of the absorbent sheet, the curved folded end portions On the opposite side of the projecting regions, wherein the absorbent sheet has a normalized fold curvature ratio of less than about 4; and a joined region joining the projecting regions of the absorbent sheet. The absorbent sheet of claim 22, wherein the fabric has a normalized fold curvature ratio of from about 0.5 to about 4. The absorbent sheet of claim 23, wherein the fabric has a normalized folded curvature ratio of about 2. The absorbent sheet of claim 22, wherein the curved folds have an average radius of curvature of from about 0.5 mm to about 2.0 mm. The cellulosic absorbent sheet of claim 22, wherein each of said protruding regions comprises a plurality of curved folds. The cellulose absorbent sheet of claim 26, further comprising an inner concave strip formed between the curved folds of each of the protruding regions.