Multi-ply tissue products and methods of manufacturing the same
Patent Information
- Authority / Receiving Office
- GB · GB
- Patent Type
- Applications
- Current Assignee / Owner
- KIMBERLY CLARK WORLDWIDE INC
- Filing Date
- 2023-05-04
- Publication Date
- 2026-06-03
AI Technical Summary
Existing tissue products face a challenge in achieving a suitable surface topography that enhances sheet bulk and softness without compromising strength, as improving one property often adversely affects others.
The development of multi-ply tissue products with a three-dimensional surface topography featuring discrete dome-shaped protrusions molded by recesses in a through-air drying fabric, which are formed before final drying, allowing for a soft and strong tissue product with improved aesthetics.
The solution provides tissue products with enhanced surface texture and perceived softness while maintaining sufficient strength, achieved through the use of discrete dome-shaped protrusions that cover a significant footprint area of the surface, ensuring a balance between bulk and stiffness.
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Abstract
Description
MULTI-PLY TISSUE PRODUCTS AND METHODS OF MANUFACTURING THE SAME BACKGROUND
[0001] Tissue products, such as facial tissues, paper towels, bath tissues, napkins, and other similar products, are designed to include several important properties. For example, the products should have good sheet bulk, a soft feel, and should have sufficient strength and durability to withstand manufacturing and use. It is also desirable to include a differentiated product appearance. Further, to improve wiping utility, it may be desirable to provide the product with a degree of surface texture. Unfortunately, however, when steps are taken to increase one property of the product, other characteristics of the product are often adversely affected.
[0002] It is generally known that molding a partially dewatered cellulosic web on a topographical papermaking fabric will enhance the finished paper product's physical properties, such as sheet bulk, stretch and softness, and aesthetics. Such molding can be applied by fabrics in a through-air dried process, such as the process disclosed in U.S. Pat. No. 5,672,248, or in a wet-pressed tissue manufacturing process, such as that disclosed in U.S. Pat. No. 4,637,859.
[0003] Exemplary papermaking fabrics are disclosed in U.S. Pat. No. 6,998,024, which teaches woven papermaking fabrics with substantially continuous machine direction ridges whereby the ridges are made up of multiple warp filaments grouped together. The ridges are higher and wider than individual warps. The wide wale ridges have a ridge width of about 0.3 cm or greater, and the frequency of occurrence of the ridges in the cross-direction (CD) is about 0.2 to about 3 per centimeter. In the examples shown in U.S. Pat. No. 6,998,024, the shute diameters are either larger than or smaller than the warp diameters, but only one shute diameter is utilized.
[0004] Other woven papermaking fabrics are disclosed in U.S. Pat. No. 7,611 ,607, which teaches fabrics having substantially continuous, not discrete, machinedirection ridges separated by valleys, where the ridges are formed of multiple warp filaments grouped together and supported by multiple shute strands of two or more diameters. The ridges are generally oriented parallel to the machine direction axis of the fabric. However, in certain instances, the ridges are oriented at an angle of about 5 degrees relative to the machine direction axis. In those instances where the ridgesare angled greater than 0° relative to the machine direction axis, they may be woven to regularly reverse direction in terms of movement in the cross-machine direction, creating a wavy appearance that can enhance the aesthetics of the resulting tissue product. While the ridges could be angled with respect to the machine direction axis, the degree of orientation is limited. Thus, the prior art woven papermaking fabrics have generally been limited to continuous topographies oriented substantially in the machine direction, with some small degree of variability.
[0005] Thus, there is a need in the art to impart a suitable surface topography to a through-air dried tissue web that does not compromise strength while providing the perception of sufficient softness.SUMMARY
[0006] Some of the aspects of the present disclosure relate to multi-ply tissue products and / or tissue webs having a three-dimensional surface topography comprising a plurality of discrete protrusions. Some aspects relate to multi-ply tissue products and / or tissue webs having a three-dimensional surface topography comprising a plurality of discrete protrusions that extend from at least one outer surface of the tissue product or web. Some aspects relate to multi-ply tissue products and / or tissue webs having a three-dimensional surface topography comprising a plurality of discrete protrusions, wherein the protrusions are molded by recesses defined in a through-air drying fabric.
[0007] In some aspects, in addition, or in the alternative, to the aspects disclosed herein, a multi-ply tissue product comprises two or more through-air dried tissue plies, and the tissue product has a first surface and a second surface, wherein the first and second surfaces are outer surfaces of the tissue product. At least the first surface comprises a three-dimensional surface topography, and the surface topography comprises a plurality of discrete dome-shaped protrusions extending outwardly from the first outer surface, each protrusion having a length:width ratio of 1 :1 to 4:1 . A footprint area of the protrusions covers at least about 15% of a total footprint area of the first surface, and the tissue product has Stiffness Index of about 10 or less.
[0008] In some aspects, in addition, or in alternative to any preceding aspects, the discrete dome-shaped protrusions are molded by recesses defined in a through-air drying fabric.
[0009] In some aspects, in addition, or in alternative to any preceding aspects, the discrete dome-shaped protrusions are imparted to the web prior to final drying of the web. Thus, in certain aspects the tissue web or product may be provided with a three-dimensional surface topography without emboss or texturing of the web or product once it has been finally dried.
[0010] In some aspects, in addition, or in alternative to any preceding aspects, the two or more through-air dried tissue plies are uncreped.
[0011] In some aspects, in addition, or in alternative to any preceding aspects, the length is measured in a machine direction and the width in the cross-machine direction, and the protrusions are spaced apart from each other on center in each row in the cross-machine direction about 3 mm to about 6 mm.
[0012] In some aspects, in addition, or in alternative to any preceding aspects, the discrete dome-shaped protrusions are arranged in rows oriented in the crossmachine direction, wherein protrusions in adjacent rows are offset from each other by at least 2 mm as measured in the machine direction from centers of protrusions in each row.
[0013] In some aspects, in addition, or in alternative to any preceding aspects, protrusions in adjacent rows are spaced apart from each other on center in the cross-machine direction by about 1 mm to about 3 mm.
[0014] In some aspects, in addition, or in alternative to any preceding aspects, the footprint area of the protrusions covers about 45% to about 65% of the total footprint area of the first surface.
[0015] In some aspects, in addition, or in alternative to any preceding aspects, a height of each protrusion is about 0.3 mm to about 1 .0 mm.
[0016] In some aspects, in addition, or in alternative to any preceding aspects, the second surface of the tissue product comprises a plurality of discrete dome-shaped protrusions that extend outwardly from the second surface.
[0017] In some aspects, in addition, or in alternative to any preceding aspects, the tissue product has a basis weight of at least about 30 grams per square meter (gsm) and a sheet bulk of about 15 cc / g to about 18 cc / g.
[0018] In some aspects, in addition, or in alternative to any preceding aspects, the tissue product has a geometric mean slope (GM Slope) less than or equal to about 10 kg and an average geometric mean tensile strength (average GMT) of about 1000 g / 3” to about 1600 g / 3”.
[0019] In some aspects, in addition, or in alternative to any preceding aspects, the tissue product has an average TS750 value of about 30 to about 50, for example, about 40 to about 50.
[0020] In some aspects, in addition, or in alternative to any preceding aspects, the first and second surfaces are substantially free from embossments.
[0021] In some aspects, in addition, or in alternative to any preceding aspects, the tissue product has a Stiffness Index from about 3 to about 10.
[0022] In some aspects, in addition, or in alternative to any preceding aspects, the tissue product has a GM Slope from about 5 kg to about 10 kg.
[0023] In some aspects, in addition, or in alternative to any preceding aspects, the tissue product has an average TS750 value of about 50 or less.
[0024] Also disclosed herein are methods of making a tissue product comprising: forming an aqueous suspension of fibers; depositing the aqueous suspension of fibers onto a forming fabric traveling at a rate of speed to form a wet web; dewatering the web to a consistency of fibers (a percentage of the fiber weight relative to a weight of a water / fiber slurry) of about 20 percent or greater based on a dry weight of the fibers; transferring the web to a through-air drying fabric defining a plurality of discrete recesses having a depth of about 0.30 mm to about 1 .5 mm, each recess defined by two adjacent machine-direction oriented protuberances and two adjacent cross-direction oriented protuberances in two adjacent rows; and through-air drying the web to form a tissue product, wherein the tissue product has two plies of the through-air dried web, and at least one outer surface of the tissue product has a plurality of discrete dome-shaped protrusions extending therefrom, each protrusion having a length:width ratio of 1 :1 to 4:1 , wherein a footprint area of the protrusionscovers at least about 15% of a total footprint area of the first surface and the tissue product has an average TS750 value of about 50 or less.
[0025] In some aspects, in addition, or in alternative to any preceding aspects, the tissue product is not embossed.
[0026] In some aspects, in addition, or in alternative to any preceding aspects, the average TS750 value of the tissue product is about 30 to about 50, for example, about 40 to about 50.
[0027] In some aspects, in addition, or in alternative to any preceding aspects, the tissue product has a Stiffness Index of about 10 or less.
[0028] Additional aspects of the disclosure will be set forth, in part, in the detailed description, figures, and claims which follow, and in part will be derived from the detailed description or can be learned by practice of the disclosure. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the disclosure as disclosed.BRIEF DESCRIPTION OF THE DRAWINGS
[0029] FIGURE 1 illustrates a woven papermaking fabric in a seamed configuration according to one aspect.
[0030] FIGURE 2 is a top schematic view of the woven papermaking fabric of FIG. 1.
[0031] FIGURES 3A-3D show various aspects of the disclosure: FIG. 3A illustrates an MD-oriented edge of the woven papermaking fabric of FIG. 1 in one aspect; FIG. 3B illustrates a CD-oriented edge the woven papermaking fabric of FIG. 1 in one aspect, FIGs. 3C and 3D illustrate a close-up top view of the woven papermaking fabric in FIG. 1 with only the web-contacting surface shown. It is understood that the fabric also comprises a machine surface that is not shown. The shown portions of the filaments are visible on the web-contacting surface. The other portions of the filaments that are not shown are a part of the machine surface or are disposed between the machine surface and the web-contacting surface.
[0032] FIGURE 4 illustrates an exemplary profilometric scan of the woven papermaking fabric of FIG. 1 .
[0033] FIGURE 5 illustrates a weave pattern used in the manufacture of a woven papermaking fabric in FIG. 4.
[0034] FIGURE 6 illustrates an exemplary woven papermaking fabric according to another aspect.
[0035] FIGURE 7 illustrates a weave pattern used in the manufacture of the woven papermaking fabric in FIG. 6.
[0036] FIGURE 8 illustrates a close-up view of one of the exemplary recesses in FIG. 4.
[0037] FIGURE 9A illustrates a profilometric scan of an outer surface of a finished tissue web molded on the woven papermaking fabric shown in FIGs. 1-3D, and FIGURE 9B illustrates a profilometric scan of the outer surface of a basesheet of the tissue web shown in FIG. 9A, prior to being finished. The images in FIGs. 9A and 9B were taken using a MicroSpy profilometer. FIGURE 9C and FIGURE 9D illustrate microscopy scans of the outer surface of a portion of the finished tissue web shown in FIG. 9A, which were taken using a Keyence microscope.
[0038] FIGURE 10 illustrates a photograph of one ply of the through air dried tissue product formed on the fabric shown in FIG. 1.
[0039] FIGURE 11 illustrates a schematic of a manufacturing process useful for manufacturing tissue webs according to one implementation.DETAILED DESCRIPTION
[0040] The present disclosure can be understood more readily by reference to the following detailed description, examples, drawings, and claims, and their previous and following description. However, before the present articles, systems, and / or methods are disclosed and described, it is to be understood that this disclosure is not limited to the specific or exemplary aspects of articles, systems, and / or methods disclosed unless otherwise specified, as such can, of course, vary. It is also to be understood that the terminology used herein is for the purpose of describing particular aspects only and is not intended to be limiting.
[0041] The following description of the disclosure is provided as an enabling teaching of the disclosure in its best, currently known aspect. To this end, those skilled in the relevant art will recognize and appreciate that many changes can be made to thevarious aspects of the disclosure described herein while still obtaining the beneficial results of the present disclosure. It will also be apparent that some of the desired benefits of the present disclosure can be obtained by selecting some of the features of the present disclosure without utilizing other features. Accordingly, those of ordinary skill in the pertinent art will recognize that many modifications and adaptations to the present disclosure are possible and may even be desirable in certain circumstances and are a part of the present disclosure. Thus, the following description is again provided as illustrative of the principles of the present disclosure and not in limitation thereof.DEFINITIONS
[0042] As used in this application and in the claims, the singular forms “a,” “an,” and “the” include the plural forms unless the context clearly dictates otherwise. Thus, for example, reference to a “filament” includes aspects having two or more such filaments unless the context clearly indicates otherwise.
[0043] It is also to be understood that the terminology used herein is for the purpose of describing particular aspects only and is not intended to be limiting. As used in the specification and in the claims, the term “comprising” can include the aspects “consisting of” and “consisting essentially of.” Additionally, the term “includes” means “comprises.”
[0044] For the terms “for example,” “exemplary,” and “such as,” and grammatical equivalences thereof, the phrase “and without limitation” is understood to follow unless explicitly stated otherwise.
[0045] Ranges can be expressed herein as from “about” one particular value and / or to “about” another particular value. When such a range is expressed, another aspect includes from the one particular value and / or to the other particular value. Similarly, when values are expressed as approximations, by use of the antecedent “about,” it will be understood that the particular value forms another aspect. It should be further understood that the endpoints of each of the ranges are significant both in relation to the other endpoint and independently of the other endpoint.
[0046] Similarly, when values are expressed as approximations, by use of the antecedent “about,” it will be understood that the particular value forms another aspect. It will be further understood that the endpoints of each of the ranges aresignificant both in relation to the other endpoint and independently of the other endpoint. Unless stated otherwise, the term “about” means within 5% (e.g., within 2% or 1%) of the particular value modified by the term “about.”
[0047] Throughout this disclosure, various aspects of the disclosure can be presented in a range format. It should be understood that the description in range format is merely for convenience and brevity and should not be construed as an inflexible limitation on the scope of the disclosure. Accordingly, the description of a range should be considered to have specifically disclosed all the possible subranges as well as individual numerical values within that range. For example, a description of a range such as from 1 to 6 should be considered to have specifically disclosed subranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., as well as individual numbers within that range, for example, 1 , 2, 2.7, 3, 4, 5, 5.3, 6 and any whole and partial increments therebetween. This applies regardless of the breadth of the range.
[0048] As used herein, the terms “optional” or “optionally” mean that the subsequently described event or circumstance may or may not occur and that the description includes instances where said event or circumstance occurs and instances where it does not.
[0049] Further, the terms “coupled” and “associated” generally mean electrically, electromagnetically, and / or physically (e.g., mechanically or chemically) coupled or linked and do not exclude the presence of intermediate elements between the coupled or associated items.
[0050] As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.
[0051] It will be understood that the terms "first," "second," etc., may be used herein to describe various elements, components, regions, layers, and / or sections. These elements, components, regions, layers, and / or sections should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer, or section from another element, component, region, layer, or a section. Thus, a first element, component, region, layer, or section discussed below could be termed a second element, component, region, layer, or section without departing from the teachings of exemplary aspects.
[0052] Spatially relative terms, such as "beneath," "below," "lower," "above," "upper," and the like, may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s). It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as "below” or "beneath" other elements or features would then be oriented "above" the other elements or features. Thus, the term "below" can encompass both an orientation of above and below. The device may be otherwise oriented (rotated 90 degrees or at other orientations), and the spatially relative descriptors used herein are interpreted accordingly.
[0053] As used herein, the term "substantially" means that the subsequently described event or circumstance completely occurs or that the subsequently described event or circumstance generally, typically, or approximately occurs.
[0054] Still further, the term “substantially” can, in some aspects, refer to at least about 80 %, at least about 85 %, at least about 90 %, at least about 91 %, at least about 92 %, at least about 93 %, at least about 94 %, at least about 95 %, at least about 96 %, at least about 97 %, at least about 98 %, at least about 99 %, or about100 % of the stated property, component, composition, or other condition for which substantially is used to characterize or otherwise quantify an amount.
[0055] As used herein, the term “papermaking fabric” means any woven fabric used for making a cellulosic web, such as a tissue sheet, either by a wet-laid process or an air-laid process. Specific papermaking fabrics within the scope of this disclosure include forming fabrics; transfer fabrics conveying a wet web from one papermaking step to another, such as described in U.S. Pat. No. 5,672,248; as molding, shaping, or impression fabrics where the web is conformed to the structure through pressure assistance and conveyed to another process step, as described in U.S. Pat. No. 6,287,426; as a structured fabric adjacent to a wet web in a nip as described in U.S. Pat. No. 7,476,293; or as a through-air drying fabric as described in U.S. Pat. Nos. 5,429,686, 6,808,599 and 6,039,838. The fabrics of the disclosure are also suitable for use as molding or air-laid forming fabrics used in the manufacture of non-woven, non-cellulosic webs such as baby wipes.
[0056] Fabric terminology used herein follows naming conventions familiar to those skilled in the art. For example, as used herein, the term “warps” generally refers to machine-direction filaments, and the term “shutes” generally refers to cross-machine direction filaments, although it is known that fabrics can be manufactured in one orientation and run on a paper machine in a different orientation.
[0057] As used herein, the term “directly adjacent” when referring to the relation of a filament to another filament means that no other filaments are disposed between the referenced filaments. For example, if two warp filaments forming a portion of a protuberance are said to be directly adjacent to one another, no other warp filaments are disposed between the two protuberance-forming warp filaments. Similarly, if two shute filaments forming a portion of a protuberance are said to be directly adjacent to one another, no other shute filaments are disposed between the two protuberanceforming shute filaments.
[0058] As used herein, the term “MD (machine directionj-oriented protuberance” generally refers to a three-dimensional element that at least partially protrudes from a base plane of the web-contacting surface of the fabric and is formed by one or more warp filaments overlaying a plurality of shute filaments that extend through the papermaking fabric between the web-contacting surface and the machine facing surface. The MD-oriented protuberance has a first end and a second end. It is understood that the first end of the MD-protuberance is closer to a first edge of the fabric in the MD-direction relative to the second end and the second end of the MD- protuberance is closer to a second edge of the fabric in the MD-direction relative to the first end. The term “CD (cross-machine directionj-oriented protuberance” generally refers to a three-dimensional element formed that at least partially protrudes from the base plane of the web-contacting surface of the fabric and is formed by at least one shute filament. Although a portion of the CD-oriented protuberances described herein may extend below an MD-oriented protuberance, the CD-oriented protuberances are still considered to be protuberances as they at least partially protrude from the base plane of the web-contacting surface of the fabric. The CD-oriented protuberance has a third end and a fourth end. It is understood that the third end of the CD-protuberance is closer to a third edge of the fabric in the CD-direction relative to the fourth end and the fourth end of the CD- protuberance is closer to a fourth edge of the fabric in the CD-direction relative to thethird end. Protuberances may be referred to herein alternatively as three- dimensional elements or simply as elements. Also, it is understood that any reference to MD-oriented protuberance and / or CD-oriented protuberance also refers to a substantially MD-oriented protuberance and / or a substantially CD-oriented protuberance.
[0059] In addition, the protuberances are discrete protuberances in that they are separate and unconnected three-dimensional elements. For example, the MD- oriented protuberances do not extend continuously past three or more CD-oriented protuberances in the MD direction, and the CD-oriented protuberances do not extend continuously past two or more MD-oriented protuberance in the CD direction of the fabric. A protuberance may be discrete despite being formed from a single continuous filament. For example, a single continuous shute filament may be woven such that it forms a plurality of discrete CD-oriented protuberances wherein each CD-oriented protuberance is defined by the third end and the fourth end of the CD- oriented protuberance as described above. In some instances disclosed herein, the third end of the CD-oriented protuberance can be interwoven with at least one warp filament forming the first end of a first MD-oriented protuberance and the fourth end of the CD-oriented protuberance can be interwoven with at least one warp filament forming the second end of a second MD-oriented protuberance, wherein the first and second MD-oriented protuberances are in different columns and the first ends of the first and second MD-oriented protuberances are in different rows. In certain implementations, a third MD-oriented protuberance can be positioned between the first and the second MD-oriented protuberances, wherein at least a portion of the third MD-oriented protuberances is disposed over the CD-oriented protuberance. In another example, a single continuous warp filament may be woven such that it forms a plurality of discrete substantially machine-direction-oriented protuberances wherein each protuberance has the first end and the second end and wherein the ends of the protuberance terminate by interweaving with shute filaments forming the third and fourth ends of the CD-oriented protuberances.
[0060] As used herein, the term “protuberance forming portion” refers to a portion of the woven warp or shute filaments that forms the protuberance. For example, in certain instances, the protuberance-forming portion may comprise a plurality of directly adjacent warp / shute filament interchanges that are woven such that the warpfilaments are woven above their respective shute filaments, forming an MD-oriented protuberance. The MD-oriented protuberance forming portion may extend substantially in the machine direction between the first end and second end of the MD-oriented protuberance and may extend over at least two shute filaments, at least three shute filaments, at least five shute filaments in the machine direction, or at least seven shute filaments, at least twenty five shute filaments, or at least thirty shute filaments as counted between the web-forming surface of the fabric and the machine facing surface of the fabric. Yet, in other instances, the protuberanceforming portion may comprise a plurality of directly adjacent warp / shute filaments woven such that at least a portion of the shute filament(s) is not woven with any warp filaments, creating a float and forming a CD-oriented protuberance. The CD-oriented protuberance forming portion may extend substantially in the cross-machine direction between the third end and the fourth end of the CD-oriented protuberance. It is further understood that in the current disclosure, at least portions of the CD- oriented protuberance forming portions can extend under MD-oriented protuberances, thereby supporting these MD-oriented protuberances.
[0061] As used herein, the term “recesses” generally refers to recesses formed in a web-contacting surface of the papermaking fabric, wherein each recess is defined by four edges and a floor. The four edges comprise two opposite edges in the machine direction and two opposite edges in the cross-machine direction. The two opposite edges in the machine direction are formed by at least a portion of two adjacent MD- oriented protuberances. The two opposite edges in the cross-machine direction are formed by end portions of the two adjacent CD-oriented protuberances. Specific examples are described below in relation to FIGs. 3C-3D, for example. The recesses described herein are discrete recesses, meaning that they are separate recesses, unconnected to each other and are non-continuous across any dimension of the fabric. For example, the recesses do not extend continuously past three or more MD-oriented protuberances or past two or more CD-oriented protuberances.
[0062] As used herein, the term “floor of a recess” is defined by an apex of the lowest visible filament, which a tissue web can contact when molding into the textured fabric. The floor can be defined by a warp knuckle, a shute knuckle, or by both. A “bottom plane” extends in the x and y directions and intersects the apex or top of the elements comprising the floor. It is understood that the papermaking material may ormay not conform to the filaments in the floor of the fabric such that the papermaking material may mold into the pores of the fabric below the apex of the lowest visible filaments.
[0063] As used herein, the term “depth of a recess” generally refers to the z- directional depth of a given recess and is measured by profilometry.
[0064] As used here, the term “a width of a recess” generally refers to the width of the recess formed on a fabric according to the present disclosure, having units of millimeters (mm). The width can be extrapolated from the profilometric measurements and / or microscopic measurement of the fabric. Generally, the recess’s width is measured along a line drawn normal to the two opposite edges of the recess in the CD direction, wherein these two opposite edges are formed by two adjacent MD-oriented protuberances.
[0065] As used here, the term “a length of a recess” generally refers to the length of the recess disposed on a fabric according to the present disclosure having units of millimeters (mm). The length can be extrapolated from ths profilometric measurements and / or microscopic measurement of the fabric. Generally, the recess’s length is measured along a line drawn normal to the two opposite edges of the recess in the MD direction that are formed by the two adjacent CD-oriented protuberances.
[0066] As used herein, the term “an element angle” generally refers to the orientation of protuberances relative to the MD axis for MD-oriented protuberances (a first element angle) and relative to the CD axis for CD-oriented protuberances (a second element angle) of the fabric. Element angle can be extrapolated from the profilometric measurements and / or microscopic measurement of the fabric.
[0067] As used herein, the term “discrete protrusion” refers to a protrusion formed in a tissue web, wherein the discrete protrusion is visually unconnected from other protrusions formed in the tissue web.
[0068] As used herein, the term “continuous” when referring to a three-dimensional element of a papermaking fabric, such as a protuberance or a pattern, means that the element extends throughout one dimension of the web-contacting surface of the papermaking fabric.
[0069] As used herein, the term “uninterrupted” generally refers to a protuberance (either MD-oriented protuberance or CD-oriented protuberance) or a portion thereof that extends without interruptions and remains above a base plane for the length of the portion of the protuberance. Undulations of the filaments forming the protuberance along its lengths, such as those resulting from twisting of warp filaments or warp filaments forming the protuberance tucking under one another, are not considered to be interruptions.
[0070] As used herein, the term “line element” refers to a three-dimensional element of a papermaking fabric, such as a protuberance, in the shape of a line, which may be continuous, discrete, interrupted, and / or a partial line with respect to a fabric on which it is present. The line element may be of any suitable shape, such as straight, bent, kinked, curled, curvilinear, serpentine, sinusoidal, and mixtures thereof. In one example, a line element may comprise a plurality of discrete elements that are oriented together to form a visually continuous line element.
[0071] As used herein, the term “pattern” refers to any non-random repeating design, figure, or motif. Generally, the fabrics described herein may comprise decorative patterns comprising a plurality of line elements and / or a plurality of recesses.However, it is not necessary that the line elements form recognizable shapes, and a repeating design of the line elements and / or recesses is considered to constitute a decorative pattern.
[0072] As used herein, the term “tissue product” refers to products made from tissue webs and includes bath tissues, facial tissues, paper towels, industrial wipers, foodservice wipers, napkins, medical pads, medical gowns, and other similar products. Tissue products may comprise one, two, three or more plies.
[0073] As used herein, the terms “tissue web” and “tissue sheet” refer to a fibrous sheet material suitable for forming a tissue product.
[0074] As used herein, the term “layer” refers to a plurality of strata of fibers, chemical(s) applied to the fibers, and / or the like, within a ply.
[0075] The term “ply” refers to a discrete product element. Individual plies may be arranged in juxtaposition to each other. The term may refer to a plurality of web-like components such as in a multi-ply facial tissue, bath tissue, paper towel, wipe, or napkin.
[0076] As used herein, the term “Basis Weight” generally refers to the bone dry weight per unit area of a tissue and is generally expressed as grams per square meter (gsm). Basis weight is measured as described in the Test Methods section below. In some aspects, the basis weight can be about 30 gsm to about 45 gsm, such as about 30 gsm to about 35 gsm, including exemplary values about 30 gsm, 30.5 gsm, 31 gsm, about 31 .5 gsm, about 32 gsm, about 32.5 gsm, about 33 gsm, about 33.5 gsm, about 34 gsm, and about 34.5 gsm. Yet in other aspects, the basis weight can be at least about 30 gsm. In other aspects, the basis weight can be about 33 to about 34 gsm, including exemplary values of about 33.2 gsm, about 33.4 gsm, about 33.6 gsm, and about 33.8 gsm.
[0077] As used herein, the term “caliper” is the representative thickness of a single tissue sheet (caliper of tissue products comprising two or more plies is the thickness of a single sheet of tissue product comprising all plies) measured in accordance with in accordance with TAPPI test methods Test Method T 580 pm-12 (Issued 2012) “Thickness (caliper) of towel, tissue, napkin and facial products.” The micrometer used for carrying out caliper measurements is an Emveco 200-A Tissue Caliper Tester (Emveco, Inc., Newberg, Oreg.). The micrometer has a load of 2 kilopascals, a pressure foot area of 2,500 square millimeters, a pressure foot diameter of 56.42 millimeters, a dwell time of 3 seconds and a lowering rate of 0.8 millimeters per second.. The caliper of a tissue product may vary depending on a variety of manufacturing processes and the number of plies in the product. Finished tissue products prepared according to this disclosure generally have a caliper greater than or equal to about 3 mils, greater than or equal to about 6 mils, greater than or equal to about 9 mils, greater than or equal to about 12 mils, greater than or equal to about or equal to 15 mils, greater than or equal to 18 mils, or greater than or equal to about21 mils. In other aspects, the caliper can be about 18 mils to about 24 mils or about22 mils to about 23 mils, including example values of about 22.2 mils, about 22.4 mils, about 22.6 mils, and about 22.8 mils.
[0078] As used herein, the term “sheet bulk” refers to the quotient of the caliper (pm) divided by the basis weight (gsm). The resulting sheet bulk is expressed in cubic centimeters per gram (cc / g). Finished tissue products prepared according to the present disclosure generally have a sheet bulk greater than or equal to about 10 cc / g. In other aspect the sheet bulk can be about 15 cc / g to about 20 cc / g or about15 cc / g to about 19 cc / g, about 15 cc / g to about 18 cc / g, about 16 cc / g to about 18 cc / g, and about 16.5 cc / g to about 18.5 cc / g, such as about 16.7 cc / g, about 16.8 cc / g, about 17.0 cc / g, about 17.2 cc / g, about 17.4 cc / g, about 17.6 cc / g, about 17.8 cc / g, about 18.0 cc / g, about 18.2 cc / g, and about 18.4 cc / g.
[0079] As used herein, the term “slope” refers to a slope of the line resulting from plotting tensile versus stretch and is an output of the MTS TestWorks™ in the course of determining the tensile strength as described in the Test Methods section herein. Slope is reported in the units of grams (g) per unit of sample width (inches) and is measured as the gradient of the least-squares line fitted to the load-corrected strain points falling between a specimen-generated force of 70 grams to 157 grams (0.687 to 1 .540 N) divided by the specimen width. Slopes are generally reported herein as having units of kilograms (kg).
[0080] As used herein, the term “geometric mean slope” (GM Slope) generally refers to the square root of the product of machine direction slope and cross-machine direction slope. GM Slope generally is expressed in units of kg. Finished tissue products prepared according to the present disclosure generally have a GM slope of less than or equal to about 10 kg. In other aspects, the GM slope can be about 5.4 kg to about 10.0 kg or about 5.8 kg to about 5.9 kg.
[0081] As used herein, the terms “geometric mean tensile” and “GMT” (also referred to as average GMT) refer to the square root of the product of the machine direction tensile strength and the cross-machine direction tensile strength of the web. Tensile testing methods are described in the Test Methods section. Finished tissue products prepared according to the present disclosure generally have an average geometric mean tensile (GMT) greater than or equal to about 1000 g / 3", greater than or equal to about 1300 g / 3”, or greater than or equal to about 1400 g / 3”. In certain aspects, the average GMT is about 1000 g / 3” to about 1600 g / 3”, including example values of about 1000 g / 3”, about 1050 g / 3”, about 1100 g / 3”, about 1 150 g / 3”, about 1200 g / 3”, about 1250 g / 3”, about 1300 g / 3”, about 1350 g / 3”, about 1400 g / 3”, about 1450 g / 3”, about 1500 g / 3”, and about 1550 g / 3”. In certain aspects, the average GMT is about 1450 g / 3” to about 1500 g / 3”, including example values of about 1455 g / 3”, about 1460 g / 3”, about 1465 g / 3”, about 1470 g / 3”, about 1475 g / 3”, about 1480 g / 3”, about 1485 g / 3”, about 1490 g / 3”, and about 1495 g / 3”.
[0082] As used herein, the term “Stiffness Index” refers to the quotient of the geometric mean tensile slope, defined as the square root of the product of the MD and CD slopes (having units of kg), divided by the average geometric mean tensile strength (having units of grams per three inches) multiplied by 1000. While the Stiffness Index may vary, finished tissue products prepared according to the present disclosure generally have a Stiffness Index less than or equal to about 5, including example values of less than or equal to about 4.5, less than or equal to about 4.3, and less than or equal to about 4.1 .
[0083] As used herein, the terms “TS750” and “TS750 value” refer to the output of the EMTEC Tissue Softness Analyzer as described in the Test Methods section. TS750 has units of dB V2 rms, however, TS750 may be referred to herein without reference to units.
[0084] Finished tissue products prepared according to certain aspects have an average TS750 value of about 30 to about 50, about 40 to about 50, about 40 to about 45, and about 42 to about 45.
[0085] The properties of the tissue web or tissue product described herein refer to the properties of the finished tissue web or tissue product, unless otherwise noted.
[0086] Although the operations of exemplary aspects of the disclosed method may be described in a particular, sequential order for convenient presentation, it should be understood that disclosed aspects can encompass an order of operations other than the particular, sequential order disclosed. For example, operations described sequentially may, in some cases, be rearranged or performed concurrently. Further, descriptions and disclosures provided in association with one particular aspect are not limited to that aspect and may be applied to any aspect disclosed.
[0087] Moreover, for the sake of simplicity, the attached figures may not show the various ways (readily discernable, based on this disclosure, by one of ordinary skill in the art) in which the disclosed system, method, and apparatus can be used in combination with other systems, methods, and apparatuses. Additionally, the description sometimes uses terms such as “produce” and “provide” to describe the disclosed method. These terms are high-level abstractions of the actual operations that can be performed. The actual operations that correspond to these terms canvary depending on the particular implementation and are, based on this disclosure, readily discernible by one of ordinary skill in the art.MULTI-PLY TISSUE PRODUCTS
[0088] The present inventors have now surprisingly discovered that certain papermaking fabrics and in particular through-air drying fabrics may be used to produce tissue webs having good surface texture without an additional embossing step or an additional step of adding a topical silicone bead to the web-contacting surface of the papermaking fabric and without negatively affecting the perceived softness. In accordance with certain aspects, the tissue products and webs described herein may be manufactured using an endless papermaking fabric, such as a through-air drying (TAD) fabric, having a plurality of MD-oriented and CD- oriented protuberances that define discrete recesses. The recesses and protuberances form a three-dimensional pattern on the web contacting surface of the fabric for cooperating with, and structuring of, the wet fibrous web during manufacturing.
[0089] Despite having a three dimensional surface topography, the tissue products are not overly rough and remain highly flexible. For example, the tissue products may have a three dimensional surface topography comprising a plurality of discrete protuberances, yet have an average TS750 value, where a higher value is generally indicative of a rougher surface, of about 50 or less, such as from about 30 to about 50, from about 30 to about 50, about 40 to about 50, about 40 to about 45, or about 42 to about 45. At the same time the tissue products may have a relatively low Stiffness Index, such as a Stiffness Index of about 10 or less, such as from about 3 to about 10 or from about 3 to about 5. The foregoing low degrees of stiffness may be achieved at tensile strengths which are sufficiently strong to withstand use, such as an average geometric mean tensile (average GMT) strength of about 1000 g / 3” or greater, such as from about 1300 g / 3” to about 1600 g / 3” for two-ply tissue products. The low degree of stiffness is generally achieved by through-air drying the tissue product during manufacture. In this manner, the tissue product may be dried without compressive forces that tend to densify and stiffen the product. Through-air drying not only facilitates non-compressive dewatering, but also allows the product to be imparted with a three-dimension surface topography. Particularly, through-air dryingfacilitates imparting the product with a surface topography comprising a plurality of discrete dome-shaped protrusions extending outwardly from the outer surface, each protrusion having a length:width ratio of 1 :1 to 4:1 , wherein a footprint area of the protrusions covers at least about 15% of a total footprint area.
[0090] The arrangement of protuberances and recesses yield a papermaking fabric having a three-dimensional surface topography, which when used to form a tissue web, produces a web having relatively uniform density, yet three-dimensional surface topography. According to some implementations, the recesses have a general rectangular prism shape, and the topography produced includes a plurality of discrete dome-shaped protrusions that have a generally rectangular or elliptical footprint. Accordingly, even though the general shape of the recess is that of a rectangular prism, the protrusion formed in the tissue web has a rounded rectangular or elliptical footprint and is dome-shaped in the Z-direction. In addition or in the alternative, the footprint of the recesses and / or the protrusions may have any other suitable closed shape, such as a rounded square shape, an oval shape, or a circular shape.
[0091] According to some aspects of the disclosure, a multi-ply tissue product comprises two or more through-air dried tissue plies. The tissue product has a first surface and a second surface. The first and second surfaces are outer surfaces of the tissue product, and at least the first surface comprises a three-dimensional surface topography that comprises a plurality of discrete dome-shaped protrusions extending outwardly from the first surface. Each protrusion has a length:width ratio of about 1 :1 to about 4:1 and a footprint area of the protrusions cover at least about 15% of the total footprint area of the first surface. The protrusions are molded by recesses defined in the through-air drying fabric while the ply with the first surface is being through-air dried. In further aspects, the second surface also comprises the three-dimensional surface topography described above, and the protrusions extending from the second outer surface are molded by recesses defined in the through-air drying fabric while the ply with the second surface is being through-air dried.
[0092] For example, in some implementations, the length:width ratio is about 1 .5:1 to about 3.5:1 or about 2:1 to about 3:1 . In addition, in some implementations, thefootprint area of the protrusions cover at least about 40%, at least about 45%, or at least about 50% of the footprint area of the respective surface. In other aspects, the footprint area of the protrusions cover about 45% to about 65% or about 50% to about 60% of the footprint area of the respective surface. In some implementations, a length is measured in a machine direction and a width in a cross-machine direction.
[0093] For example, in some implementations, the protrusions are spaced apart from each other on center in each row in the cross-machine direction by about 3 mm to about 6 mm, including exemplary values of about 3.2 mm, about 3.5 mm, about 3.8 mm, about 4.0 mm, about 4.2 mm, about 4.5 mm, about 4.8 mm, about 5.0 mm, about 5.2 mm, about 5.5 mm, and about 5.8 mm. In addition, in some implementations, the protrusions in adjacent rows are spaced apart from each other on center in the cross-machine direction by about 1 to about 3 mm, including exemplary values of about 1 .1 mm, about 1 .2 mm, about 1 .3 mm, about 1 .4 mm, about 1 .5 mm, about 1 .6 mm, about 1 .7 mm, about 1 .8 mm, about 1 .9 mm, about 2.0 mm, about 2.1 mm, about 2.2 mm, about 2.3 mm, about 2.4 mm, about 2.5 mm, about 2.6 mm, about 2.7 mm, about 2.8 mm, and about 2.9 mm. Furthermore, in some implementations, adjacent rows, as measured from the centers of protrusions in each row, are offset from each other by at least about 2 mm as measured in the machine direction.
[0094] In some implementations, a height of each protrusion is about 0.3 to about 1 .0 mm, including exemplary values of about 0.4 mm, about 0.5 mm, about 0.6 mm, about 0.7 mm, about 0.8 mm, and about 0.9 mm.
[0095] In some aspects, the tissue products have a Stiffness Index of about 10 or less, such as about 9.5 or less or about 9.0 or less. In certain aspects, the Stiffness Index is from about 3 to about 10, such as about 4 to about 10. The foregoing Stiffness Index may be achieved at a GM Slope less than or equal to about 10 kg, such as about 5.4 kg to about 10.0 kg or about 5.8 kg to about 5.9 kg. For example, a Stiffness Index of about 3.5 to about 4.5 may be achieved at a GM Slope of about 5.0 kg to about 10.0 kg.
[0096] In some aspects, the tissue products have an average TS750 value of about 50 or less, such as about 45 or less or such as about 40 or less. In certain aspects,the average TS750 value is from about 15 to about 50, about 20 to about 50, about 30 to about 50, about 40 to about 45, or about 42 to about 45.
[0097] In some implementations, the two or more through-air dried tissue plies are uncreped.
[0098] Furthermore, in some implementations, the second surface of the tissue product includes a plurality of dome-shaped protrusions like the dome-shaped protrusions described above.
[0099] In certain aspects, the first surface of the tissue product is a surface of a first ply, and the second surface of the tissue product is a surface of a second ply. In some aspects, the first and second plies are formed separately as tissue webs on the through-air drying fabric. In further aspects, the first and second plies may be subjected to further converting to produce a multi-ply tissue product. Exemplary through-air drying systems and exemplary converting operations are discussed below.
[0100] For example, FIG. 9A is a profilometry scan of a finished multi-ply tissue web according to one implementation, using a MicroSpy profilometer. The finished multiply tissue web shown in FIG. 9A is formed from basesheets formed on the papermaking fabric shown in FIGS. 1-3D. FIG. 9B is a profilometry scan of a single ply basesheet of the multi-ply tissue web shown in FIG. 9A. FIGs. 9C and 9D are microscopy scans of a portion of the finished tissue web in FIG. 9A taken using a Keyence microscope along the bolded line shown in the upper right portion of each figure. FIG. 10 is a photograph of one ply of the through air dried tissue product formed on the fabric shown in FIGs. 1-3D. The discrete dome-shaped protrusions are molded by recesses defined in the through-air drying fabric.
[0101] Each protrusion has a length of about 3.9 mm to about 4.1 mm, (as measured in the machine direction) and a width of about 1 .9 mm to about 2.1 mm, (as measured in the cross-machine direction). The footprint area of the protrusions cover about 50% to about 60%, including exemplary values of about 51%, about 52%, about 53%, about 54%, about 55%, about 56%, about 57%, about 58%, and about 59%, of the footprint area of each outer surface of the two-ply tissue web. A height of each protrusion is about 0.35 mm to about 0.55 mm, including exemplary values of about 0.36 mm, about 0.37 mm, about 0.38 mm, about 0.39 mm, about 0.40 mm,about 0.41 mm, about 0.42 mm, about 0.43 mm, about 0.44 mm, about 0.45 mm, about 0.46 mm, about 0.47 mm, about 0.48 mm, about 0.49 mm, about 0.50 mm, about 0.51 mm, about 0.52 mm, about 0.53 mm, and about 0.54 mm. The protrusions are spaced apart from each other on center in each row in the crossmachine direction by about 3.5 mm to 4.5 mm, including exemplary values of about 3.6 mm, about 3.7 mm, about 3.8 mm, about 3.9 mm, about 4.0 mm, about 4.1 mm, about 4.2 mm, about 4.3 mm, and about 4.4 mm. The protrusions in adjacent rows are spaced apart from each other on center in the cross-machine direction by about 1 .5 mm to about 2.5 mm, including exemplary values of about 1 .6 mm, about 1 .7 mm, about 1 .8 mm, about 1 .9 mm, about 2.0 mm, about 2.1 mm, about 2.2 mm, about 2.3 mm, and about 2.4 mm. Adjacent rows, as measured from the centers of protrusions in each row, are offset from each other by about 3 mm to about 4 mm, including exemplary values of about 3.1 mm, about 3.2 mm, about 3.3 mm, about 3.4 mm, about 3.5 mm, about 3.6 mm, about 3.7 mm, about 3.8 mm, and about 3.9 mm.
[0102] The finished web has an average TS750 value of about 42 to about 45, including exemplary values of about 42.2, about 42.5, about 42.7, about 43.0, about 43.2, about 43.5, about 43.7, about 44.0, about 44.2, about 44.5, and about 44.7. In addition, according to some aspects, the finished tissue products and webs disclosed herein have a basis weight of at least about 30 gsm and a sheet bulk of about 15 cc / g to about 18 cc / g.
[0103] Table 1 below summarizes example properties of the example finished multiply tissue web (“Inventive” Products) shown in FIGs. 9A-9D and 10 and known products.TABLE 1
[0104] These properties, alone or in combination with the structure of the domeshaped protrusions extending outwardly from the outer surfaces of the tissue product, contribute to a perception of softness.
[0105] The surface texture of the tissue products and webs described herein may be expressed as an average TS750 value as measured using an EMTEC Tissue Softness Analyzer (Emtec Electronic GmbH, Leipzig, Germany) and described in the Test Method section below.
[0106] While having improved properties, the finished tissue products and / or webs prepared according to the present disclosure continue to be strong enough to withstand use by a consumer. For example, tissue webs prepared according to the present disclosure may have an average geometric mean tensile (GMT) greater than or equal to about 1000 g / 3", greater than or equal to about 1300 g / 3”, or greater than or equal to about 1400 g / 3”. In some aspects, the average GMT is about 1450 g / 3” to about 1500 g / 3”, including example values of about 1455 g / 3”, about 1460 g / 3”, about 1465 g / 3”, about 1470 g / 3”, about 1475 g / 3”, about 1480 g / 3”, about 1485 g / 3”, about 1490 g / 3”, and about 1495 g / 3”.
[0107] Generally, the finished tissue products and / or webs disclosed herein have a basis weight of less than or equal to about 45 gsm, less than or equal to about 40 gsm, less than or equal to about 35 gsm, less than or equal to about 30 gsm, or lessthan or equal to about 25 gsm. In some aspects, the basis weight is about 30 gsm to about 45 gsm or about 30 gsm to about 35 gsm, including example values of about 30.5 gsm, about 31 .0 gsm, about 31 .5 gsm, about 32.0 gsm, about 32.5 gsm, about 33.0 gsm, about 33.5 gsm, about 34.0 gsm, and about 34.5 gsm. Yet in other aspects, the basis weight can be at least about 30 gsm. In some aspects, the basis weight is about 33 gsm to about 34 gsm, including example values of about 33.2 gsm, about 33.4 gsm, about 33.6 gsm, and about 33.8 gsm.
[0108] At the foregoing basis weights the finished tissue products and / or webs may have a sheet bulk greater than or equal to about 10 cc / g, greater than or equal to about 15 cc / g, or greater than or equal to about 17 cc / g. In some aspects, the sheet bulk is about 15 cc / g to about 20 cc / g, about 15 cc / g to about 19 cc / g, about 15 cc / g to about 18 cc / g, about 16 cc / g to about 18 cc / g, or about 16.5 cc / g to about 18.5 cc / g, including example values of about 16.7 cc / g, about 16.8 cc / g, about 17.0 cc / g, about 17.2 cc / g, about 17.4 cc / g, about 17.6 cc / g, about 17.8 cc / g, about 18.0 cc / g, about 18.2 cc / g, and about 18.4 cc / g.
[0109] In certain implementations, a finished through-air dried tissue product comprises a plurality of wood pulp fibers and has a basis weight of about 32 gsm to about 35 gsm and a sheet bulk of about 16 cc / g to about 18 cc / g.
[0110] In some implementations, the tissue products and webs described herein have good softness, a high degree of texture and good bulk. For example, the finished tissue products and / or webs may have an average TS750 value of about 50 or less, such as about 45 or less, or such as about 40 or less. For example, the average TS750 value may be about 30 to about 50, such as about 40 to about 50, about 40 to about 45, or about 42 to about 45 and a sheet bulk of at least about 10 cc / g, such as about 15 cc / g to about 20 cc / g.
[0111] In yet other implementations, the tissue products and webs described herein are not overly stiff. For example, the instant finished tissue products may have a Stiffness Index less than or equal to about 5, less than or equal to about 4.5, less than or equal to about 4.3, or less than or equal to about 4.1 . The foregoing Stiffness Index may be achieved at a GM Slope less than or equal to about 10 kg, such as about 5.4 kg to about 10.0 kg or about 5.8 kg to about 5.9 kg. For example, astiffness index of about 3.5 to about 4.5 may be achieved at a GM Slope of about 5.0 kg to about 10.0 kg.
[0112] The tissue products and webs described herein are wet-laid and comprise a plurality of fibers, such as cellulosic pulp fibers. In some aspects, the plurality fibers can form a fibrous structure. In some examples, the tissue products comprise a plurality of wood pulp fibers. In one example, the tissue produces consist essentially of a plurality of wood pulp fibers. Suitable cellulosic fibers for use in connection with this disclosure include secondary (recycled) papermaking fibers and virgin papermaking fibers in all proportions. Such fibers include, for example and without limitation, hardwood and softwood kraft pulp fibers. In another example, the fibrous structure may comprise a plurality of non-wood pulp fibers, for example plant fibers, synthetic staple fibers, and mixtures thereof.
[0113] Accordingly, in certain implementations, at least one tissue web employed in a multi-ply tissue product is manufactured using a papermaking fabric, such as a patterned through-air drying fabric, that imparts a three-dimensional pattern to the product or web. The pattern results in a web that has a moderate degree of topography, evidenced by an average TS750 value of about 30 to about 50, about 40 to about 50, about 40 to about 45, and about 42 to about 45. In certain implementations, the average TS750 value is about 42 to about 45.
[0114] In other implementations, a multi-ply, such as a two-ply, tissue product, for example, a folded facial tissue product, has an average TS750 value of about 30 to about 50, about 40 to about 50, about 40 to about 45, and about 42 to about 45. In certain implementations, the average TS750 value is about 42 to about 45.
[0115] In yet another implementation, a multi-ply, such as a two-ply, tissue product, comprises at least one uncreped, through-air dried patterned web, wherein the tissue product exhibits an average TS750 value of about 30 to about 50, about 40 to about 50, about 40 to about 45, and about 42 to about 45. In certain implementations, the average TS750 value is about 42 to about 45.
[0116] Non-limiting examples of processes for making fibrous structures include known wet-laid papermaking processes, for example, through-air-dried papermaking processes. Such processes include steps of preparing a fiber composition in the form of a suspension in a medium, either wet, more specifically aqueous medium, ordry, more specifically gaseous, e.g., with air as medium. The aqueous medium used for wet-laid processes is oftentimes referred to as a fiber slurry. The fibrous slurry is then used to deposit a plurality of fibers onto a forming wire, fabric, or belt such that an embryonic fibrous structure is formed, after which drying and / or bonding the fibers together results in a tissue web. Further processing of the tissue web may be carried out such that a finished tissue product is formed.
[0117] Examples of papermaking processes and techniques useful in forming tissue webs and products according to the present disclosure include, for example, those disclosed in U.S. Pat. Nos. 5,048,589, 5,399,412, 5,129,988 and 5,494,554, all of which are incorporated herein in a manner consistent with the present disclosure. In one aspect, the tissue web is formed by through-air drying and may be either creped or uncreped. When forming multi-ply tissue products, the separate plies can be made from the same process or different processes as desired.
[0118] The forming process of the present disclosure may be any conventional forming process known in the papermaking industry. Such formation processes include, but are not limited to, Fourdriniers, roof formers such as suction breast roll formers, and gap formers such as twin wire formers and crescent formers.
[0119] The drying process can be any non-compressive drying method which tends to preserve the bulk or thickness of the wet web including, without limitation, through- air drying, infra-red radiation, microwave drying, etc. Because of its commercial availability and practicality, through-air drying is well known and is one commonly used means for non-compressively drying the web for purposes of this disclosure. The web is dried to final dryness on the through-air drying fabric, without being pressed against the surface of a Yankee dryer, and without subsequent creping.
[0120] The tissue webs disclosed herein may be converted into single or multi-ply tissue products, and the webs may be converted into rolled or sheets of a folded tissue product. Rolled tissue products may comprise a plurality of connected, but perforated sheets that may be dispensed as adjacent sheets. In another example, the tissue products may be in the form of discrete sheets that are stacked within and dispensed from a container, such as a box.
[0121] Tissue webs disclosed herein may be homogeneous or may be layered. If layered, the tissue web may comprise two or more layers, such as two, three, or fourlayers. If desired, various chemical compositions may be applied to one or more layers of the multi-layered tissue web to further enhance softness and / or reduce the generation of lint or slough. For example, in some aspects, a wet strength agent can be utilized, to further increase the strength of the tissue product. As used herein, a “wet strength agent” is any material that, when added to pulp fibers, can provide a resulting web or sheet with a wet geometric tensile strength to dry geometric tensile strength ratio in excess of about 0.1 . Typically these materials are termed either “permanent” wet strength agents or “temporary” wet strength agents. As is well known in the art, temporary and permanent wet strength agents may also sometimes function as dry strength agents to enhance the strength of the tissue product when dry.
[0122] Wet strength agents may be applied in various amounts, depending on the desired characteristics of the web. For instance, in some aspects, the total amount of wet strength agents (e.g., KYMENE, a registered trademark of Solenis) added can be about 1 to about 30 pounds per ton (Ibs / T), such as about 3 to about 20 Ibs / T or about 3 to about 10 Ibs / T of the dry weight of fibrous material. The wet strength agents can be incorporated into any layer of a multi-layered tissue web.
[0123] A chemical debonder can also be applied to soften the web. Specifically, a chemical debonder can reduce the amount of hydrogen bonds within one or more layers of the web, which results in a softer product. Depending on the desired characteristics of the resulting tissue product, the debonder can be utilized in varying amounts. For example, in some aspects, the debonder can be applied in an amount of about 1 to about 30 Ibs / T, in some aspects of about 3 to about 20 Ibs / T, and in some aspects of about 4 to about 15 Ibs / T of the dry weight of fibrous material. The debonder can be incorporated into any layer of the multi-layered tissue web.
[0124] Any material capable of enhancing the soft feel of a web by disrupting hydrogen bonding can generally be used as a debonder in the present disclosure. In particular, as stated above, it is typically desired that the debonder possess a cationic charge for forming an electrostatic bond with anionic groups present on the pulp. Some examples of suitable cationic debonders can include, but are not limited to, quaternary ammonium compounds, imidazolinium compounds, bis-imidazolinium compounds, diquaternary ammonium compounds, polyquaternary ammoniumcompounds, ester-functional quaternary ammonium compounds (e.g., quaternized fatty acid trialkanolamine ester salts), phospholipid derivatives, polydimethylsiloxanes and related cationic and non-ionic silicone compounds, fatty and carboxylic acid derivatives, mono and polysaccharide derivatives, polyhydroxy hydrocarbons, etc. For instance, some suitable debonders are described in U.S. Pat. Nos. 5,716,498, 5,730,839, and 6,211 ,139, all of which are incorporated herein in a manner consistent with the present disclosure.
[0125] Still other suitable debonders are disclosed in U.S. Pat. Nos. 5,529,665 and 5,558,873, both of which are incorporated herein in a manner consistent with the present disclosure. In particular, U.S. Pat. No. 5,529,665 discloses the use of various cationic silicone compositions as softening agents.
[0126] In certain aspects, the base web can be formed by an uncreped through-air drying process such as that illustrated in FIG. 11 in which a twin wire former having a papermaking headbox 1 deposits a furnish of an aqueous suspension of papermaking fibers onto a plurality of forming fabrics, such as the outer forming fabric 35 and the inner forming fabric 3, thereby forming a wet tissue web 36. The forming process of the present disclosure may be any conventional forming process known in the papermaking industry. Such formation processes include, but are not limited to, Fourdriniers, roof formers such as suction breast roll formers, and gap formers such as twin wire formers and crescent formers.
[0127] The wet tissue web 36 forms on the inner forming fabric 3 as the inner forming fabric 3 revolves about a forming roll 14. The inner forming fabric 3 serves to support and carry the newly-formed wet tissue web 36 downstream in the process as the wet tissue web 36 is partially dewatered to a consistency of about 10 percent based on the dry weight of the fibers. Additional dewatering of the wet tissue web 36 may be carried out by known papermaking techniques, such as vacuum suction boxes, while the inner forming fabric 3 supports the wet tissue web 36. The wet tissue web 36 may be additionally dewatered to a consistency of at least about 20 percent based on the dry weight of the fibers, including example values of about 20 to about 40 percent and about 20 to about 30 percent.
[0128] The forming fabric 3 can generally be made from any suitable porous material, such as metal wires or polymeric filaments. For instance, some suitablefabrics can include, but are not limited to, Albany 84M and 94M, available from Albany International (Albany, N.Y.) Asten 856, 866, 867, 892, 934, 939, 959, or 937; Asten Synweve Design 274, all of which are available from Asten Forming Fabrics, Inc. (Appleton, Wis.); and Voith 2164 available from Voith Fabrics (Florence, MS). Forming fabrics or felts comprising nonwoven base layers may also be useful, including those of Scapa Corporation made with extruded polyurethane foam such as the Spectra Series.
[0129] The wet web 36 is then transferred from the forming fabric 3 to a transfer fabric 8. In this implementation the wet tissue web 36 can have a consistency of about 10 to about 35 percent, including example values of about 20 to about 30 percent based on the dry weight of the fiber present within a set volume of water. As used herein, a “transfer fabric” is a fabric that is positioned between the forming section and the drying section of the web manufacturing process. For example, example transfer fabrics are described in U.S. Patent No. 11 ,286,623, the contents of which are incorporated by reference in their entirety.
[0130] Transfer to the transfer fabric 8 may be carried out with the assistance of positive and / or negative pressure. For example, in one aspect, a vacuum shoe 9 can apply negative pressure such that the forming fabric 3 and the transfer fabric 8 simultaneously converge and diverge at the leading edge of the vacuum slot. Typically, the vacuum shoe 9 supplies negative machine direction pressure at levels of about 7 to about 11 inches of mercury (e.g., about 9 inches of mercury). As stated above, the vacuum transfer shoe 9 (negative pressure) can be supplemented or replaced by the use of positive pressure from the opposite side of the web to blow the web onto the transfer fabric 8. In some aspects, other vacuum shoes can also be used to assist in drawing the web 36 onto the surface of the transfer fabric 8.
[0131] Typically, the transfer fabric 8 travels at a slower speed than the forming fabric 3 to enhance the MD and CD stretch of the web, which generally refers to the stretch of a web in its machine (MD) or cross-machine direction (CD) (expressed as percent elongation at sample failure). For example, the relative speed difference between the two fabrics can be about 1 to about 30 percent, including example ranges of about 5 to about 30 percent and about 10 percent to about 30 percent, such as about 28 percent. This is commonly referred to as “rush transfer”. During“rush transfer,” many of the bonds of the web are believed to be broken, thereby forcing the sheet to bend and fold into the depressions on the surface of the transfer fabric 8. Such molding to the contours of the surface of the transfer fabric 8 may increase the MD and CD stretch of the web. Rush transfer from one fabric to another can follow the principles taught in any one of the following patents, U.S. Pat. Nos. 5,667,636, 5,830,321 , 4,440,597, 4,551 ,199, 4,849,054, all of which are hereby incorporated by reference herein in a manner consistent with the present disclosure.
[0132] The wet tissue web 36 is then transferred from the transfer fabric 8 to a through-air drying fabric 11. The transfer fabric 8 travels at approximately the same speed as the through-air drying fabric 11. However, in alternative implementations, a second rush transfer may be performed as the web is transferred from the transfer fabric 8 to a through-air drying fabric 11. This rush transfer is referred to herein as occurring at the second position and is achieved by operating the through-air drying fabric 11 at a slower speed than the transfer fabric 8. By performing rush transfer at two distinct locations, i.e. , the first and the second positions, a tissue product having increased CD stretch may be produced.
[0133] In addition to rush transferring the wet tissue web 36 from the transfer fabric 8 to the through-air drying fabric 11 , the wet tissue web 36 may be macroscopically rearranged to conform to the surface of the through-air drying fabric 11 to give the desired bulk and appearance to the resulting dried tissue web. This is done with the aid of a vacuum transfer roll 12 or a vacuum transfer shoe like vacuum shoe 9. If desired, the through-air drying fabric 11 can be run at a speed slower than the speed of the transfer fabric 8 to further enhance MD stretch of the resulting absorbent tissue product. The transfer may be carried out with vacuum assistance to ensure conformation of the wet tissue web 36 to the topography of the through-air drying fabric 11.
[0134] The web is transferred to the through-air drying fabric for final drying, for example, with the assistance of vacuum, to ensure macroscopic rearrangement of the web to give the desired bulk and appearance. The vacuum pressure at this transfer is about 3 inches of mercury. The use of separate transfer and through-air drying fabrics can offer various advantages since it allows the two fabrics to be designed specifically to address key product requirements independently. It isunderstood that the sheet topology can be completely changed from the transfer fabric to through-air drying fabric, and fibers can be macroscopically rearranged (e.g., significant fiber-fiber movement) on the through-air drying fabric.
[0135] While supported by the through-air drying fabric 11, the wet tissue web 36 is dried to a final consistency of about 94 percent based on the dry weight of the fiber or greater by a through-air dryer 130. The web 150 then passes through the winding nip between the reel drum 220 and the reel 26 and is wound into a roll of tissue 25 for subsequent converting, such as plying, laminating, calendaring, embossing, slitting, cutting, folding, and packaging.
[0136] Suitable through-air drying fabrics may include, for example, papermaking fabrics having a plurality of three-dimensional protuberances, such as protuberances formed by woven filaments, disposed on the web contacting surface of the fabric. Example through-air drying fabrics suitable for producing the patterns disclosed herein are described below in the section entitled “Woven Papermaking Fabric.”
[0137] After forming the tissue webs, the tissue webs are converted into multi-ply tissue products. For example, for a two-ply tissue product, two rolls of tissue webs are unwound, calendared, laminated together, and wound as a two-ply tissue product.
[0138] As described above, the tissue product of the present disclosure can generally be formed by any of a variety of papermaking processes known in the art. In particular, in some implementations, the tissue web is formed by through-air drying and is uncreped.
[0139] The foregoing papermaking fabrics may be used in the manufacture of a through-air dried tissue web having a three-dimensional surface topography disposed on the first or second surface of the tissue web, the topography comprising a plurality of discrete dome-shaped protrusions. In certain implementations, the protrusions have a height at least about 0.15 mm, such as about 0.3 to about 1 .0 mm (e.g., about 0.3 to about 0.8 mm) for a finished product, including exemplary values of about 0.5 mm, about 0.6 mm, about 0.7 mm, and about 0.8 mm. The web may be incorporated into a tissue product, such as two-ply tissue product, having a modest degree of surface texture, such as an average TS750 value of about 30 toabout 50. Despite having a three-dimensional surface topography and a modest degree of texture, the tissue products are generally perceived as soft.WOVEN PAPERMAKING FABRIC
[0140] The present inventors have now surprisingly discovered the formation of the woven papermaking fabrics having the patterns disclosed herein. Even further, it was surprisingly discovered that the disclosed woven papermaking fabrics may be used to produce tissue webs and products having high bulk, visually appealing aesthetics, and improved perceived softness without compromising operating efficiency. Papermaking fabrics of the current disclosure are generally directed to woven fabrics but may be suitable as base fabrics upon which to add additional material to enhance tissue physical properties or aesthetics. For example, the woven fabrics disclosed herein may be used in the manufacture of a papermaking fabric having a foraminous woven base member surrounded by a hardened photosensitive resin framework. In other instances, the instant woven fabrics may be used in the manufacture of a papermaking fabric having a foraminous woven base member with a polymeric material disposed thereon by printing, extruding, or well- known additive manufacturing processes.
[0141] The present fabrics may be used in the manufacture of a broad range of fibrous structures, particularly wet-laid fibrous structures and more particularly, wet- laid tissue products such as bath tissues, facial tissues, paper towels, industrial wipers, foodservice wipers, napkins, and other similar products. Further, the fabrics disclosed herein are well suited for use in a wide variety of tissue manufacturing processes. For example, the fabrics may be used as TAD fabrics in either uncreped or creped applications to generate aesthetically acceptable patterns and good, bulky tissue product attributes. Alternatively, the fabrics may be used as impression fabrics in wet-pressed papermaking processes.
[0142] In some aspects, disclosed herein is a woven papermaking fabric having a three-dimensional structure and is defined by a machine direction axis and a crossmachine direction axis. In certain aspects, the disclosed woven papermaking fabric has a textured sheet contacting surface with a machine and cross-machine direction topography. In still further aspects, the disclosed herein woven papermaking fabric can comprise a plurality of machine direction (MD)-oriented warp filaments and aplurality of cross-machine direction (CD)-oriented shute filaments that are interwoven together to provide a machine contacting surface of the fabric and an opposed web contacting surface of the fabric. It is understood that the terms “sheet contacting surface,” “sheet contacting side,” “web contacting surface,” and “web contacting side” can be used interchangeably and refer to the surface or side of the fabric that receives papermaking compositions. The opposite side or surface of the fabric is referred to as a “machine contacting surface” or “machine contacting side.”
[0143] In some aspects, the web contacting surface can also comprise a plurality of MD-oriented protuberances formed from two or more warp filaments woven to form a first float above corresponding one or more shute filaments, such that the two or more warp filaments in each of the plurality of MD-oriented protuberances are spaced apart. In still further aspects, each of the plurality of MD-oriented protuberances can comprise from 2 to 10 warp filaments, including exemplary values of 3, 4, 5, 6, 7, 8, and 9 filaments that can float above a corresponding one or more shute filaments and where each warp filament is spaced apart from directly adjacent warp filaments in the MD-oriented protuberance. In some exemplary and unlimiting aspects, each of the plurality of MD-oriented protuberances can comprise three (3) warp filaments that float above corresponding one or more shute filaments. In aspects disclosed herein, the warp filaments can float above 1 to 34 shute filaments, including exemplary values of 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, and 30 shute filaments in MD-direction.
[0144] It is understood that the fabrics disclosed herein are multi-layer fabrics with a 1 :1 ratio of top (web-contacting side) to bottom (machine contacting side) shutes. In such aspects, it is understood that for every CD filament in the web-contacting side of the fabric, there is a CD filament on the machine contacting surface of the fabric. The machine contacting surface weave structure is described by the Z stitches in the weave diagram (see FIG. 5, row 1 , column 1 ). The Z stich represents a machine contacting side shute that passes under warp filaments 2-12. The web-contacting side filament follows the weave diagram such that the web-contacting side CD filament passes under warps 3, 4, 7, 8, 9, and 12. To continue the example, row 2 also shows a Z stitch. This Z stitch resides in column 5 which represents a machine contacting side shute that passes under warp filaments 1 -4 and 6-12. The webcontacting side CD filament passes under warps 1 -3 and 7-9, and so on.
[0145] In some aspects, all of the plurality of MD-oriented protuberances are substantially similar within a given fabric. It is understood, however, that the fabric is formed by interweaving shute and warp filaments, and it is possible that some of the MD-oriented protuberances can be slightly different from the others. However, it is also understood that this difference can be not significant, and each of the plurality of MD-oriented protuberances is substantially the same. It is understood that the MD- oriented protuberances, in one aspect, together term a substantially fiat outermost top surface of toe fabric. Therefore, it is expected that the changes in the MD- oriented protuberance shape or dimensions are not significant.
[0146] However, it is also understood that the aspects where the plurality of MD- oriented protuberances are not substantially the same and can comprise a predetermined pattern are also disclosed. For example, and without limitations, in some aspects, the fabric can comprise MD-oriented protuberances that can float above a different number of corresponding shute filaments. For example, and without limitations, some of the protuberances along a MD direction can float above 5 shute filaments, while other protuberances along the same MD direction can float above 2 or 10 shute filaments. Again, it is understood that the numbers are exemplary and any disclosed herein, a number of the shute filaments can be positioned below the MD-oriented protuberance.
[0147] In some aspects, the plurality of CD- oriented protuberances further comprise a first shute filament and a second shute filament disposed at each side of the at least one shute filament and wherein the first shute filament and the second shute filament are positioned together to push the at least one shute filament up (relative to the base plane) to form the CD-oriented protuberances. In such aspects, the first and the second shute filaments, bundled together with the at least one shute filament, can create a buckle that pushes the CD-oriented protuberance above the webcontacting surface. In some aspects, it can be more than three shute filaments that form a bundle participating in the formation of the CD-oriented protuberance. For example, in some aspects, the CD- oriented protuberance can comprise two or more shute filaments on one side of the at least one shute filament and one or more shute filaments on the other side of the at least one shute filament positioned such that all these additional shute filaments push the at least one shute filament up to form the CD-oriented protuberance.
[0148] In still further aspects, the at least one shute filament of the plurality of CD- oriented protuberances forms a second float.
[0149] The MD-oriented protuberance 22a, as for example, shown in FIG. 3C, can be formed from two or more warp filaments and has the first end 1a and the second end 1b. In the specific example shown in FIG. 3C, the MD-oriented protuberance comprises three separate warp filaments 2a-2c.
[0150] The CD-oriented protuberance 24a (as shown in FIG. 3C) can be formed from one or more shute filaments having the third end 4a in FIG. 3C and the fourth end 4b in FIG. 3C. In such aspects, a portion of the MD-oriented protuberance, for example the spaced apart filaments of portion 25, overlays the CD-oriented protuberance 24a in FIG. 3C. It can be further seen that the third end 4a of the CD protuberance 24a extends above at least one warp fiber 2c when it forms the first end 1a of the adjacent MD-oriented protuberance 22b. The fourth end 4b of the CD-oriented protuberance 24a extends above at least one warp fiber 2a when it forms the second end 1b of the adjacent MD-oriented protuberance 22c.
[0151] In still further aspects, the plurality of CD-oriented protuberances are discrete. It is understood that in the aspects in which the CD-oriented protuberance is formed by a continuous filament interwoven by an MD-protuberance forming portion of the warp filaments, the CD-oriented protuberance is considered to be discrete.
[0152] In still further aspects, the plurality of CD-oriented protuberances and the plurality of MD-oriented protuberances are arranged to form a plurality of recesses. A top surface of the recess 26a shown in FIG. 3D is defined by four edges. As described above, the four edges comprise two opposite edges in the cross-machine direction 27a and 27b and two opposite edges in the machine direction 29a and 29b. The two opposite edges in the cross-machine direction are formed by at least a portion of two adjacent MD-oriented protuberances 22a’ and 22b’. The two opposite edges in the machine direction are formed by the end portions 4b’ and 4a’ of the two adjacent CD-oriented protuberances 24a’ and 24b' respectively, in further aspects, the outermost top surface of the web contacting surface is substantially flat.
[0153] In still further aspects, each of the plurality of recesses has a depth of about 0.3 mm to about 1 .5 mm. In still further aspects, each of the plurality of recesses can have a depth of about 0.3 mm to about 1 .1 mm, such as about 0.3 mm to about 0.9mm, including exemplary values of about 0.4 mm, about 0.5 mm, about 0.6 mm, and about 0.7 mm. It is further understood that the depth of the recess can be adjusted based on the type of filaments used to form the fabric. More specifically, it is understood that the filaments formed from different polymers and / or having different diameter can provide the woven fabric having different depths of recesses. It is also understood that the fabric having the desired depth can be chosen depending on the final application. For example, fabrics used to form a facial tissue may have a different recess depth from fabrics used to form a medical garment.
[0154] In still further aspects, the disclosed fabric can have a plurality of recesses having a substantially identical depth amongst the plurality of recesses, such as a difference of less than or equal to about 10 %, less than or equal to about 9 %, less than or equal to about 8%, less than or equal to about 7%, less than or equal to about 6%, less than or equal to about 5%, less than or equal to about 4%, less than or equal to about 3%, less than or equal to about 2%, less than or equal to about 1%, less than or equal to about 0.5%, or even less than or equal to about 0.1%.
[0155] In still further aspects, the floor of each recess can define a bottom plane. In some aspects, apexes of the plurality of MD-oriented protuberances can form a first plane and apexes of the plurality of CD-oriented protuberances can form a second plane. In such exemplary and unlimiting aspects, the first plane is positioned above the second plane. In still further aspects, the z-directional distance between the bottom plane and the highest apex of MD-oriented protuberance can be about 0.3 mm to about 1 .1 mm, including exemplary values of about 0.4 mm, about 0.5 mm, about 0.6 mm, about 0.7 mm, about 0.9 mm, and about 1 .0 mm.
[0156] The width of a given MD-oriented protuberance may vary depending on the number of warp filaments forming the protuberance, the diameter of the filament, the spacing between the filaments, and the type of polymer used to form the warp filaments. In some aspects, the diameter of warp filaments can be greater than or equal to about 0.1 mm, such as about 0.1 mm to about 1 .5 mm, including exemplary values of about 0.2 mm, about 0.3 mm, about 0.4 mm, about 0.5 mm, about 0.6 mm, about 0.7 mm, about 0.8 mm, about 0.9 mm, about 1 .0 mm, about 1.1 mm, about 1 .2 mm, about 1 .3 mm, and about 1 .4 mm. It is understood that the warp filament can have any diameter value between any two mentioned above values.
[0157] It is understood that the width of the MD-oriented protuberance as measured from center to center spacing of topographical elements can be greater than or equal to about 0.2 mm, for example, about 0.2 mm to about 1 .5 mm, including exemplary values of about 0.3 mm, about 0.4 mm, about 0.5 mm, about 0.6 mm, about 0.7 mm, about 0.8 mm, about 0.9 mm, about 1 .0 mm, about 1 .1 mm, about 1 .2 mm, about 1 .3 mm, and about 1 .4 mm. It is also understood that the width value can fall within any of the two values disclosed above.
[0158] In still further aspects, the first float can be about 1 mm to about 25 mm, including exemplary values of about 2 mm, about 3 mm, about 4 mm, about 5 mm, about 6 mm, about 7 mm, about 8 mm, about 9 mm, about 10 mm, about 1 1 mm, about 12 mm, about 13 mm, about 14 mm, about 15 mm, about 16 mm, about 17 mm, about 18 mm, about 19 mm, and about 20 mm.
[0159] In still further aspects, the length of the MD-oriented protuberance can be about 1 mm to about 25 mm, including exemplary values of about 2 mm, about 3 mm, about 4 mm, about 5 mm, about 6 mm, about 7 mm, about 8 mm, about 9 mm, about 10 mm, about 1 1 mm, about 12 mm, about 13 mm, about 14 mm, about 15 mm, about 16 mm, about 17 mm, about 18 mm, about 19 mm, and about 20 mm.
[0160] The width of a given CD-oriented protuberance may vary depending on the number of shute filaments forming the protuberance, the diameter of the filament, and the type of polymer used to form the warp filaments. In some aspects, the diameter of shute filaments can have any of the values described above in relation the diameter of the warp filaments.
[0161] It is understood that the width of the CD-oriented protuberance can be about 0.2 mm to about 6 mm, including exemplary values of about 0.3 mm, about 0.4 mm, about 0.5 mm, about 0.6 mm, about 0.7 mm, about 0.8 mm, about 0.9 mm, about 1 .0 mm, about 1 .5 mm, about 2.0 mm, about 2.5 mm, about 3.0 mm, about 3.5 mm, about 4.0 mm, about 4.5 mm, about 5.0 mm, and about 5.5 mm. It is also understood that the width value can fall within any of the two values disclosed above.
[0162] In still further aspects, the second float can be about 0.2 mm to about 6 mm, including exemplary values of about 0.3 mm, about 0.4 mm, about 0.5 mm, about 0.6 mm, about 0.7 mm, about 0.8 mm, about 0.9 mm, about 1 .0 mm, about 1 .5 mm,about 2.0 mm, about 2.5 mm, about 3.0 mm, about 3.5 mm, about 4.0 mm, about 4.5 mm, about 5.0 mm, and about 5.5 mm.
[0163] In still further aspects, the length of the CD-oriented protuberance can be about 1 mm to about 12 mm, for example about 1 to about 10, including exemplary values of about 2 mm, about 3 mm, about 4 mm, about 5 mm, about 6 mm, and about 7 mm.
[0164] In still further aspects and depending on the intended application of the papermaking fabrics, the shute count can be about 20 to about 250 ends per inch, including exemplary values of about 30, about 50, about 70, about 90, about 110, about 130, about 150, about 170, about 190, about 210, and about 230 ends per inch.
[0165] In still further aspects, the warp filaments and shute filaments can comprise the same material. In still further aspects, the warp filament and shute filaments can have the same diameter. Yet, in still further aspects, the warp filaments are different from the shute filaments. In still further aspects, the warp filament can have a diameter different from the diameter of shute filaments.
[0166] In still further aspects, the plurality of warp filaments and / or the plurality of shute filaments comprise polyester, polyethylene sulfide, polyamide, or any combination thereof. It is understood that the polyamides disclosed herein can include any known in the art polyamides, such as, for example, nylon 6, nylon 6,6, nylon 6, 10, nylon 1 1 , nylon 12, and the like. It is understood that the term “nylon,” as used herein, is considered to encompass all known in the art nylons suitable for the desired application.
[0167] In still further aspects, the polyester can include any known in the art polyesters, for example and without limitations, it can include, polyethylene terephthalate (PET), polytrimethylene terephthalate, polybutylene terephthalate (PBT) homorpolymers and copolymers, and the like. In some other aspects, the exemplary polyesters can include polyethylene terephthalate) (PET), poly(trimethylene terephthalate) (PTT), poly(butylene terephthalate) (PBT), polyethylene isophthalate), poly(octamethylene terephthalate), poly(decamethylene terephthalate), poly(pentamethylene isophthalate), poly(butylene isophthalate), poly(hexamethylene isophthalate), poly(hexamethylene adipate),poly(pentamethylene adipate), poly(pentamethylene sebacate), poly(hexamethylene sebacate), poly( 1 ,4-cyclohexylene terephthalate), poly( 1 ,4-cyclohexylene sebacate), polyethylene terephthalate-co-sebacate), and poly(ethylene-co-tetramethylene terephthalate).
[0168] In further aspects, the plurality of warp filaments and / or the plurality of shute filaments can comprise polymers that can include but are not limited to polyesters, co-polyesters, ultra-high molecular weight polyethylene, polyethylene sulfide polyethylene, polypropylene, polytetrafluoroethylene, expanded polytetrafluorethylene, polyvinylidene fluoride, polyurethane, polyethers, polyureas, nylon, copolymers thereof, or a combination thereof.
[0169] In still further aspects, the recesses in the plurality of recesses are discrete. In certain aspects, the recesses are disposed such that they are offset from each other in the MD direction. In certain aspects, the plurality of recesses are disposed along the MD direction at a first angle relative to the MD axis. In certain aspects, the first angle can be from 0° to about 90°, including exemplary values of about 0.05°, about 1 °, about 5°, about 10°, about 15°, about 20°, about 25°, about 30°, about 35°, about 40°, about 45°, about 50°, about 55°, about 60°, about 65°, about 70°, about 75°, about 80°, and about 85°.
[0170] In still further aspects, the recesses are disposed substantially parallel along the CD axis along the fabric width. Yet, also contemplated are aspects where the recesses can be disposed from an angle from 0° to about 20°, including exemplary values of about 0.1 °, about 0.5°, about 1 .0°, about 1 .5°, about 2.0°, about 2.5°, about 3.0°, about 3.5°, about 4.0°, about 4.5°, about 5.0°, about 5.5°, about 6.0°, about 6.5°, about 7.0°, about 7.5°, about 8.0°, about 8.5°, about 9.0°, about 9.5°, about 10.0°, about 10.5°, about 1 1 .0°, about 11 .5°, about 12.0°, about 12.5°, about 13.0°, about 13.5°, about 14.0°, about 14.5°, about 15.0°, about 15.5°, about 16.0°, about 16.5°, about 17.0°, about 17.5°, about 18.0°, about 18.5°, about 19.0°, and about 19.5° from each other in CD-direction
[0171] In certain aspects, the plurality of MD-oriented protuberances are substantially parallel to each other. In still further aspects, the plurality of MD-oriented protuberances are substantially parallel to the MD axis. In yet other aspects, theplurality of MD-oriented protuberances are disposed along the MD direction at a first element angle relative to the MD axis. In some aspects, the first element angle relative to the MD axis can be from 0° to about 10°, including exemplary values of about 0.1 °, about 0.5°, about 1 .0°, about 1 .5°, about 2.0°, about 2.5°, about 3.0°, about 3.5°, about 4.0°, about 4.5°, about 5.0°, about 5.5°, about 6.0°, about 6.5°, about 7.0°, about 7.5°, about 8.0°, about 8.5°, about 9.0°, and about 9.5°. It is understood, in such aspects, the warp filaments forming the MD-protuberance can provide a non-zero first element angle as described above.
[0172] In still further aspects, the plurality of the CD-oriented protuberances disclosed herein can be substantially parallel to each other in the MD direction. In yet still further aspects, the plurality of CD-oriented protuberances can be substantially parallel to the CD axis. In still further aspects, the plurality of CD-oriented protuberances are disposed along the CD direction at a second element angle relative to the CD axis. In such examples, the second element angle to the CD axis can be from 0° to about 10°, including exemplary values of about 0.1 °, about 0.5°, about 1 .0°, about 1 .5°, about 2.0°, about 2.5°, about 3.0°, about 3.5°, about 4.0°, about 4.5°, about 5.0°, about 5.5°, about 6.0°, about 6.5°, about 7.0°, about 7.5°, about 8.0°, about 8.5°, about 9.0°, and about 9.5°. It is understood, in such aspects, the shute filaments forming the CD-protuberance can provide a non-zero second element angle as described above.
[0173] In still further aspects, and as disclosed herein, the MD and CD oriented protuberances are disposed such that each of the MD-oriented protuberances forms a continuous edge defining a portion of at least two of the plurality of recesses. For example, as shown in FIG. 3D, recesses 26a and 26b are formed in two adjacent rows such that a first portion 112a of the MD-protuberance 22a forms one edge 27c of the recess 26b in one row and a second portion 112b of the MD-oriented protuberance 22a forms an edge 27a of the recess 26a in an adjacent row. Both portions 112a and 112b are shown as rectangles in dashed line type in FIG. 3D.
[0174] In still further aspects, the MD and CD-oriented protuberances are arranged so that the discrete recesses can have any number of different irregular and regular shapes. For example, and without limitations, the recesses can have a substantially square or substantially rectangular shape as viewed in plain view.
[0175] In still further aspects, the fabrics disclosed herein are used to form a paper product. In such aspects, the plurality of recesses are configured to receive a papermaking composition during a papermaking process. In still further aspects, the plurality of recesses are configured to form a plurality of discrete protrusions on a formed paper product. The shape of these discrete protrusions will be dependent on the shape of the recesses.
[0176] The dimensions of the recesses can be determined by various means known to those skilled in the art, including simple photographs of plan views and crosssections. Surface profilometry is particularly suitable, however, because of its precision. One such surface profilometry method of characterizing the recess structure is hereinafter described.
[0177] In some aspects, each of the plurality of recesses has a length along the MD axis having any of the recess length values disclosed above. It is understood that in such aspects, the length is measured between centers of the two adjacent CD- oriented protuberances along the MD direction.
[0178] The MD-oriented protuberances are generally spaced apart from one another in the cross-machine direction (CD) of the fabric. The length measured between centers of the two adjacent MD-oriented protuberances along the CD direction defines a width of the recess. In some aspects, the MD-oriented protuberances are spaced apart from one another at a similar distance forming the recesses having substantially identical widths. In yet still, further aspects, wherein each of the plurality of recesses has a width along the CD axis selected from any of the recess width values disclosed above.
[0179] FIGs. 1 and 2 illustrate a papermaking fabric according to one aspect of the present disclosure. The papermaking fabric 10 can include, as shown in FIG. 2, a first longitudinal end 13 and a second longitudinal end 15 that can be joined to form a seam 50, as shown in FIG. 1 . The fabric further comprises opposed lateral edges 17, 19.[0180JA close-up view of papermaking fabric 10 is shown in FIG. 3C. As shown there, papermaking fabric 10 generally comprises a plurality of filaments that can be woven together. As will be described in further detail below, the filaments can include a plurality of warp filaments and a plurality of shute filaments that can be woventogether to form a machine-contacting surface 18 and a web-contacting surface 20 of the woven papermaking fabric 10, which is shown in FIGs. 1 and 2. The web contacting surface 20 is opposite and spaced apart from the machine contacting surface 18. The machinery employed in a typical papermaking operation is well- known in the art and may include, for example, vacuum pickup shoes, rollers, and drying cylinders.
[0181] In some aspects, papermaking fabric 10 comprises a through-air drying fabric useful for transporting an embryonic tissue web across drying cylinders during the tissue manufacturing process. However, in other aspects, the woven papermaking fabric 10 can comprise a transfer fabric for transporting an embryonic tissue web from forming wires to a through-air drying fabric. In these aspects, the web contacting surface 20 supports the embryonic tissue web, while the opposite surface, the machine contacting surface 18, contacts the surrounding machinery.
[0182] The web contacting surface 20 of the papermaking fabric 10 can include a plurality of MD-oriented protuberances 22 and a plurality of CD-oriented protuberances 24, which are arranged to define discrete recesses 26. The MD and CD-oriented protuberances are generally disposed on the web contacting surface 20 of fabric 10 and cooperate with and structure the wet fibrous web during manufacturing. For example, as illustrated in FIG. 2, the web contacting surface 20 of the papermaking fabric 10 can include a plurality of discrete substantially MD- oriented protuberances, such as, for example, 22a-22b and CD-oriented protuberances 24a-24b that together form a recess 26a.
[0183] In certain aspects, substantially MD and CD-oriented protuberances 22, 24 can form about 5 % of the surface area of the web contacting surface 20 to less than 100 % of the surface area of the web contacting surface 20, including exemplary values of about 8 %, about 10 %, about 12 %, about 15 %, about 18 %, about 20 %, about 22 %, about 25 %, about 28 %, about 30 %, about 32 %, about 35 %, about 38 %, about 40 %, about 42 %, about 45 %, about 48 %, about 50 %, about 52 %, about 55 %, about 58 %, about 60 %, about 62 %, about 65 %, about 68 %, about 70 %, about 72 %, about 75 %, about 78 %, about 80 %, about 82 %, about 85 %, about 88 %, about 90 %, about 92 %, about 95 %, and about 98 % of the surface area of the web contacting surface 20. Of course, it can be appreciated that in someaspects, the MD and CD-oriented protuberances 22 and 24 can form a percentage of the surface area of the web contacting surface 20 outside of these ranges and still be within the scope of the present disclosure.
[0184] The recesses 26 are generally permeable to liquids and allow water to be removed from a wet-laid sheet of cellulosic filaments by the application of differential fluid pressure, by evaporative mechanisms, or both when drying air passes through the sheet while on the papermaking fabric 10 or a vacuum is applied through the papermaking fabric 10. Without being bound by any particular theory, it is believed that the arrangement of protuberances 22, 24 and recesses 26 may facilitate the molding of the sheet of cellulosic filaments causing filaments to deflect in the z- direction and generate the caliper of and aesthetic patterns on, the resulting tissue web. It is further understood that these patterns can form discrete protrusions on the surface of the resulting tissue web. The specific shape of these protrusions can depend on the desired application and on the specific shape of the plurality of recesses present in the fabric. In certain aspects, the recesses shown herein can result in protrusions on the surface of the tissue web having a dome shape. In yet still further aspects, the protrusions formed on the surface of the tissue web can contribute to the feeling (or perception) that the tissue is softer when it is compared to the tissue without the protrusions.
[0185] While the MD and CD-oriented protuberances 22, 24 are illustrated in FIGs. 1 and 2 are of the same design, the disclosure is not so limited, and it is contemplated that a papermaking fabric can include a plurality of protuberances forming recesses having two or more different shapes. The MD and CD-oriented protuberances can form an array of rows and / or columns and, in some aspects, can be evenly spaced in either or both the machine direction (MD) and the cross-machine direction (CD).
[0186] FIG. 3A illustrates an MD-oriented edge of fabric 10, showing CD-oriented protuberances 24 overlaying a number of warp filaments 14. FIG. 3B shows a CD- oriented edge of the fabric 10 showing MD-oriented protuberances 22.
[0187] As mentioned above, FIGs. 3C and 3D illustrate an exemplary view of a portion of the web-contacting surface of the papermaking fabric 10 (as shown in FIGs. 1 and 2) having substantially MD- and CD-oriented protuberances. The exemplary recess 26a (shown as a rectangle in solid line type in FIG. 3D) is formedby exemplary MD-oriented protuberances 22a’ and 22b’ and exemplary CD-oriented protuberances 24a’ and 24b’.
[0188] In some aspects, an exemplary MD-protuberance 22a (as shown in FIG. 3C) can be formed from three warp filaments 2a-2c spaced apart from each other. The skilled practitioner making a similar fabric would expect filaments 2a and 2c to buckle underneath filament 2b. However, such a configuration was not observed here. Instead, all warp filaments 2a-2c are spaced apart, which was unexpected.
[0189] In still further aspects, the at least a portion of the MD-oriented float 25 in FIG. 3C is positioned above the CD protuberance 24a. This exemplary CD-oriented protuberance 24a can be formed from one or more shute filaments having the third end 4a in FIG. 3C and the fourth end 4b in FIG. 3C. In such aspects, the spaced apart filaments as shown in portion 25 of the MD-oriented protuberance are overlaying the CD-oriented protuberance 24a in FIG. 3C, while the third 4a and fourth ends 4b of the CD-oriented protuberance 24a interweave with at least one warp filament forming the first end 1a and the second end 1b of the MD-oriented protuberances 22b and 22c adjacent to each side of the MD-oriented protuberance 22d that includes portion 25. Without wishing to be bound by any theory, it is hypothesized that the configuration in which the CD float crosses under the middle of portion 25 in FIG. 3C of the MD-oriented protuberance 22d and terminates between the ends of the adjacent MD protuberances (22b and 22c respectively) forms the MD-oriented protuberance having all the filaments spaced apart.
[0190] The MD and CD-oriented protuberances generally have a length that is measured in the principal dimension of the protuberance in the plane defined by the machine direction and cross-machine direction at a given location. The length of the MD-oriented protuberances can be measured in the machine direction (MD) and in the cross-machine direction (CD) for CD-oriented protuberances. Here, the length of the MD and / or CD-oriented protuberances can be substantially similar to the length of the first and the second floats formed by the warp and shute filaments, respectively. In still further aspects, the length of the discrete MD-protuberance can have any value from any of the MD-oriented protuberance length values disclosed above.
[0191] Similarly, the length of the CD-oriented protuberance can have any of the CD- oriented protuberance length values disclosed above.
[0192] As described above, the protuberances can also have a width. The protuberance width is generally measured normal to the principal dimension of the protuberance in a plane defined by the cross-machine direction (CD) at a given location. The width of the protuberance can have any of the protuberance width values disclosed above.
[0193] If a papermaking fabric includes multiple protuberances, it is contemplated that a plurality of or all of the protuberances can be configured substantially the same in terms of any one or more of characteristics of height, width, or length. It is also contemplated that a papermaking fabric can be configured with protuberances configured such that one or more characteristics of height, width, or length of the protuberances vary from one protuberance to another protuberance. In certain aspects, substantially all of the MD- oriented protuberances may have similar characteristics of height, width, or length, and substantially all of the CD-oriented protuberances may have similar characteristics of height, width, or length, where the characteristics of the MD and CD oriented protuberances is different.
[0194] The spacing and arrangement of protuberances may vary depending on the desired properties and appearance of tissue products manufactured therewith. In some aspects, the protuberances can be spaced apart across the entire crossmachine direction length of the papermaking fabric, such as illustrated in FIG. 3C and 3D. Additionally or alternatively, the protuberances can be configured to extend continuously in one dimension of the papermaking fabric. Of course, the direction of the protuberance alignments (machine direction, cross-machine direction, or diagonal) discussed above refers to the principal alignment of the protuberance. Within each alignment, the protuberances may have segments aligned in other directions but aggregate to yield the particular alignment of the entire protuberances.
[0195] Generally, the protuberances (such as 22 and 24 shown in FIGs. 1-3C) are spaced apart from one another so as to define a recess 26 therebetween. In certain instances, such as when the disclosed papermaking fabrics are used as a through- air drying fabric, the filaments of the embryonic tissue web are deflected in the z- direction by the protuberances forming the recess.
[0196] The profilometric data of the exemplary fabric illustrated in FIGs. 3C-3D is further shown in FIG. 4. As shown in FIG. 4, the MD-oriented protuberances 22a’” and 22b’”, together with the CD-oriented protuberances 24a’” and 24b’”, form a recess 26a’”. Each recess has floor 28’” that defines the bottom plane of the fabric.
[0197] The apexes of the plurality of MD-oriented protuberances (represented by exemplary MD-protuberance 30’”) form a first plane, and the apexes of the plurality of CD-oriented protuberances (represented by exemplary CD-protuberance 32’”) form a second plane. In certain aspects, the first plane is positioned above the second plane ensuring the outermost web-contacting surface of the fabric stays flat.
[0198] The spacing of protuberances can be provided such that the tissue web conforms to the protuberances and is deposited in recess 26a’” without tearing. The size, spacing and arrangement of the recesses may be optimized to provide the resulting tissue web with desired aesthetics or physical properties. Here, for example, the recesses are discrete and are offset from each other in the MD direction. In some aspects, the plurality of recesses can be disposed along the MD direction at a first angle 29 relative to the MD axis. The first angle can have any of the first angle values disclosed above.
[0199] As shown in FIG. 4, the MD-oriented protuberances can be substantially parallel to each other (42a and 42b). In some aspects, the plurality of MD-oriented protuberances are substantially parallel to the MD axis. While in other aspects, the plurality of MD-oriented protuberances are disposed along the MD direction at a first element angle 42a relative to the MD axis 40 that is greater than 0°. It can also be seen that each MD-oriented protuberance is composed of three separate warp filaments spaced apart from each other.
[0200] Several exemplary woven papermaking fabrics are illustrated in the attached figures. The illustrated fabrics are woven so as to form a plurality of discrete recesses and may be useful in the manufacture of tissue products, particularly the manufacture of through-air dried tissue products. The illustrated fabrics generally have recess depth values of any of the recess depth values disclosed above.
[0201] Exemplary weave patterns and methods of manufacturing a woven papermaking fabric are also shown herein. In one aspect, the papermaking fabric could be manufactured by providing a first set of filaments and asecond set of filaments that are woven in a weave pattern. The first set of filaments can serve as warp filaments in a loom, and the second set of filaments can serve as shute filaments in a loom. The method can additionally include weaving the shute filaments with the warp filaments in a lateral direction to provide a web-contacting side of the woven papermaking fabric and a machine-contacting side of the woven papermaking fabric and to provide a plurality of substantially MD-oriented protuberances and a plurality of substantially CD oriented protuberances on the web contacting surface of the woven papermaking fabric. Weaving the shute filaments with the warp filaments can be accomplished by following weave patterns.
[0202] Various weave patterns can be used to guide the weaving of the shute filaments with the warp filaments and provide substantially CD- and MD-oriented protuberances disposed on the web-contacting surface of the papermaking fabric. A weave pattern of the fabric shown in FIGs. 3C-3D and FIG. 4 is shown in FIG. 5, which illustrates a portion of the weave pattern used to form a papermaking fabric according to the present disclosure.
[0203] The weave pattern 100 of FIG. 5 is described in detail below. However, the principles of weave pattern 100 may be adapted to form a broad range of unit cells that can be further combined to form a variety of patterns according to the present disclosure. Pattern 100 can include a plurality of warp filaments 14 generally aligned in the machine direction (MD) and a plurality of shute filaments 16 generally aligned in the cross-machine direction (CD). The weave pattern 100 can be configured on a loom (not pictured) such that the web contacting surface 20 of the papermaking fabric 10 (as labeled in FIG. 1) will be facing out from the page, and the machine contacting surface 18 of the papermaking fabric 10 (as labeled in FIG. 1) will be facing into the page. As disclosed above, the Z siiches are formed on the machine contacting surface of the fabric. Of course, it is contemplated that a weave pattern 100 could be configured in the opposite orientation on a loom. Each interchange of a specific warp filament 14 and a specific shute filament 16 of the weave pattern that includes a vertical line segment (or a capital letter “I”) provides a notation that the specific warp filament 14 is woven above the specific shute filament 16 at that interchange. For example, the interchange of warp filament No. 1 and shute filament No. 2 includes such a vertical line segment in FIG. 5, and thus, warp filament No. 1 is woven above shute filament No. 2. In some circumstances,interchanges of warp filaments and shute filaments that have the vertical line segment (or the capital letter “I”) that will lead to the development of a protuberance are also shaded with a cross-hatching pattern for purposes of clarity of perceiving the protuberances of the weave pattern provided herein. In other instances where a specific warp filament 14 lies between a specific shute filament 16 at a given interchange, the pattern is left blank, such as in the interchange of warp filament No. 2 and shute filament No. 1 of FIG. 5.
[0204] The weave pattern 100 can be configured to provide MD and CD-oriented protuberances 22, 24. For example, the illustrated MD-oriented protuberance 22 (shown as a rectangle in solid, heavier line type) can be formed from three separate warp filaments 2a-2c. It can be seen that the MD-oriented protuberance 22 is formed by protuberance-forming portions (shown as a rectangle in solid, heavier line type of warp filaments 5,6, and 7 that overlay (form a float) above the shute filaments 7-17. The CD-oriented protuberance 24 is formed by a protuberance-forming portion (shown as a rectangle in solid, heavier line type in a horizontal direction) of at least one shute filament 12. The portions 5a and 5b of the shute filaments 11 and 13 adjacent protuberance-forming portions of the shute filament 12 participate in the formation of the protuberance 24 by pushing the protuberance-forming portion of the shute filament 12 up above the surface of the fabric. The MD protuberance 22 overlays the CD protuberance 24.
[0205] It is understood that MD- and CD-protuberance forming portions (shown in solid rectangular) can be of various lengths and / or widths to provide MD- and CD- oriented protuberances 22 and 24 the desired shapes and sizes.
[0206] It can be seen, for example, that the CD-protuberance 24 in row 12 has the third end 4a and the fourth end 4b.
[0207] The float length of the warp filaments woven above the shute floats to form the MD-oriented protuberance may vary, as discussed above. For example, the warp filaments forming the MD-oriented protuberance may have a float length from four to twenty, such as from eight to sixteen and, or from ten to fourteen. Similarly, the float length of the shute filaments below the warp filament can vary depending on the desired application.
[0208] FIG. 6 shows a profilometric study of an additional fabric 10 , in which exemplary MD-oriented protuberances 22 , suchand CD- oriented protuberances 24””’, such as 24aand 24b , form a recess 26a
[0209] The weave pattern 100shown in FIG. 7 (of the fabric of FIG. 6) can be configured to provide MD and CD-oriented protuberances 22 , 24 For example, the illustrated MD-oriented protuberance 22””’ can be formed from three separate warp filaments 2a -2c The MD-oriented protuberance 22is formed by protuberance-forming portions (shown with a rectangle in a heavier solid line in a vertical direction) of warp filaments 5,6, and 7 that overlay (form a float) above the shute filaments 6-14. The CD-oriented protuberance 24 is formed by a protuberance-forming portion (shown as a rectangle in a heavier solid line in a horizontal direction) of at least one shute filament 10 woven. The portions 5a and of the shute filaments 9 and 11 adjacent protuberance-forming portions of the shute filament 10 participate in the formation of the protuberance 24 by pushing the protuberance-forming portion of the shute filament 5 up above the surface of the fabric. Interestingly, as shown in FIG. 6, the shute filaments 5ado not bundle underneath of the CD-forming shoot 24 Instead, these shute filaments are also positioned above the surface of the fabric.
[0210] It is understood that MD- and CD-protuberance forming portions can be of various lengths and / or widths to provide MD- and CD- oriented protuberances 22 and 24 the desired shapes and sizes.
[0211] FIG. 8 shows a close-up illustration of recess 26 from FIG. 4 having a width w (or CD-length) and a length I (or MD-length). The data is shown in Table 2.Table 2. Recess dimensionsTEST METHOD
[0212] The recess depth, as well as other fabric properties, can be measured using a non-contact profilometer. To prevent any debris from affecting the measurements, all images are subjected to thresholding to remove the top and bottom 0.5 mm of the scan. To fill any holes resulting from the thresholding step and provide a continuous surface on which to perform measurements, non-measured points are filled. The image is also flattened by applying a rightness filter.
[0213] Profilometry scans of the fabric contacting surface of a sample were created using an FRT MicroSpy® Profile profilometer (FRT of America, LLC, San Jose, Calif.) and then analyzing the image using Nanovea® Ultra software version 7.4 (Nanovea Inc., Irvine, Calif.). Samples were cut into squares measuring 145x145 mm. The samples were then secured to the x-y stage of the profilometer using an aluminum plate having a machined center hole measuring 2x2 inches, with the fabric contacting the surface of the sample facing upwards, being sure that the samples were laid flat on the stage and not distorted within the profilometer field of view.
[0214] Surface smoothness was analyzed using an EMTEC Tissue Softness Analyzer (“TSA”) (Emtec Electronic GmbH, Leipzig, Germany). The TSA comprises a rotor with vertical blades which rotate on the test piece applying a defined contact pressure. Contact between the vertical blades and the test piece creates vibrations, which are sensed by a vibration sensor. The sensor then transmits a signal to a PC for processing and display. The signal is displayed as a frequency spectrum. The frequency analysis in the range of approximately 200 to 1000 Hz represents the surface properties of the test piece. To measure TS750, a frequency analysis in the range of approximately 200 to 1000 Hz is performed with the amplitude of the peak occurring at 750 Hz being recorded as the average TS750 value. The average TS750 value represents the surface smoothness of the sample. A high amplitude peak correlates to a rougher surface. TS750 has units of dB V2rms. The average TS750 value generally represents the structure of the sample which includes such things as any three-dimensional surface topography. Generally, samples having smooth surfaces with relatively low degrees of three-dimensional surface topography will produce a lower TS750 peak.
[0215] Test samples were prepared by cutting a circular sample having a diameter of 112.8 mm. All samples were allowed to equilibrate at TAPPI standard temperature and humidity conditions for at least 24-hours prior to completing the TSA testing. Only one ply of tissue is tested. Multi-ply samples are separated into individual plies for testing. The sample is placed in the TSA with the softer (dryer or Yankee) side of the sample facing upward. The sample is secured and the Softness Values measurements are started via the PC. The PC records, processes and stores all of the data according to standard TSA protocol. The reported TS750 values is the average of five replicates, each one with a new sample.
[0216] Tensile testing was done in accordance with TAPPI test method T-576 “Tensile properties of towel and tissue products (using constant rate of elongation)” wherein the testing is conducted on a tensile testing machine maintaining a constant rate of elongation and the width of each specimen tested is 3 inches. More specifically, samples for dry tensile strength testing were prepared by cutting a 3±0.05 inch (76.2±1 .3 mm) wide strip in either the machine direction (MD) or crossmachine direction (CD) orientation using a JDC Precision Sample Cutter (Thwing- Albert Instrument Company, Philadelphia, Pa., Model No. JDC 3-10, Serial No. 37333) or equivalent. The instrument used for measuring tensile strengths was an MTS Systems Sintech 11 S, Serial No. 6233. The data acquisition software was an MTS TestWorks® for Windows Ver. 3.10 (MTS Systems Corp., Research Triangle Park, N.C.). The load cell was selected from either a 50 Newton or 100 Newton maximum, depending on the strength of the sample being tested, such that the majority of peak load values fall between 10 to 90 percent of the load cell's full scale value. The gauge length between jaws was 4±0.04 inches (101 .6±1 mm) for facial tissue and towels and 2±0.02 inches (50.8±0.5 mm) for bath tissue. The crosshead speed was 10±0.4 inches / min (254±1 mm / min), and the break sensitivity was set at 65 percent. The sample was placed in the jaws of the instrument, centered both vertically and horizontally. The test was then started and ended when the specimen broke. The peak load was recorded as either the “MD tensile strength” or the “CD tensile strength” of the specimen depending on direction of the sample being tested. Ten representative specimens were tested for each product or sheet and the arithmetic average of all individual specimen tests was recorded as the appropriate MD or CD tensile strength the product or sheet in units of grams of force per 3inches of sample. The average geometric mean tensile (GMT) strength was calculated and is expressed as grams-force per 3 inches of sample width. Tensile energy absorbed (TEA) and slope are also calculated by the tensile tester. TEA is reported in units of gm-cm / cm2. Slope is recorded in units of kg. Both TEA and Slope are directional dependent and thus MD and CD directions are measured independently. Geometric mean TEA (GM TEA) and geometric mean slope (GM Slope) are defined as the square root of the product of the representative MD and CD values for the given property.
[0217] Basis weight is measured by selecting sixteen (16) finished products (also referred to as sheets) of the sample and making two (2) stacks of eight (8) sheets. In the event the sample consists of perforated sheets of bath or towel tissue, the perforations must be aligned on the same side when stacking the usable units. A precision cutter is used to cut each stack into exactly 7.62x7.62 cm (3.0x3.0 inch) squares. The two stacks of cut squares are combined to make a basis weight pad of sixteen (16) squares thick. The basis weight pads are placed in a commercial oven (e.g. Blue M Industrial Ovens serial #10089811 from Thermal Product Solutions or equivalent) maintained at 105 ±2 °C for 60 ±5 minutes. The basis weight pad is then weighed on a top loading balance with a minimum resolution of 0.01 grams. The top loading balance must be protected from air drafts and other disturbances using a draft shield. Weights are recorded when the readings on the top loading balance become constant. The mass of the sample (grams) per unit area (square meters) is calculated and reported as the basis weight, having units of grams per square meter (gsm).EXAMPLES
[0218] Basesheets were made using a through-air dried papermaking process commonly referred to as “uncreped through-air dried” (“UCTAD”) and generally described in U.S. Pat. No. 5,607,551 , the contents of which are incorporated herein in a manner consistent with the present disclosure. In all cases the basesheets were produced from a furnish comprising northern softwood kraft (NSWK) and eucalyptus hardwood kraft (EHWK) using a layered headbox fed by three stock chests such that the webs having three layers (two outer layers and a middle layer) were formed. The two outer layers comprised EHWK and the middle layer comprised NSWK.Debonder was added to one of the outer most furnish layers and a permanent wet strength additive was added to all of the layers. Table 3 indicates the forming conditions for making the basesheet using an inventive TAD fabric.TABLE 3
[0219] The tissue web was formed on a TissueForm V forming fabric (commercially available from Voith Fabrics, Florence, MS), vacuum dewatered to approximately 25 percent consistency of fibers based on the dry weight of the fibers and then subjected to rush transfer to a Monoshape M44-AJ-171 transfer fabric (commercially available from AstenJohnson, Appleton, Wl) , which is a 44x36 fabric woven with 0.35 mm diameter machine direction strands and 0.45 mm cross-machine direction strands. The transfer fabric was traveling at a speed about 28 percent slower than the forming fabric. The web was then transferred to a TAD fabric, such as the TAD fabrics illustrated in FIGs. 1-3D, 4 and 6. The web was then non-compressively dried and wound into a parent roll. The known tissue web was formed using the sameprocess as described above except the web was transferred to a known TAD fabric (not shown).
[0220] The samples were converted into finished product by placing parent rolls of basesheet in two unwinds with the orientation such that the TAD fabric side of the basesheet was facing outward for each of the two plies. The two basesheet plies were then passed through a pair of steel calendar rolls with a loading force of about 30 to about 60 pounds per lineal inch (PLI) (e.g., 50 PLI). Calendared plies were trimmed and passed over a folding board to form the sheet into a V-fold configuration. After folding the plies were wound onto a reel drum to create a sausage of tissue, which was subsequently transferred to a band saw and cut into clips of facial tissue product.
[0221] To gain an understanding of the topography of each product a Keyence VHX- 5000 Digital Microscope was used to measure the height of the three-dimension surface topography of the product. Products were placed under a glass microscope slide, which was weighted, and a 3D stitched image was taken of the area under the glass slide. Once the 3D image was taken, a line was drawn across the middle MD position of the image and the average function was used to create 10 lines spaced at 5 pm increments from which a CD profile of the product was generated. The height of the protrusions was measured based upon the CD profile and varied about 300 pm to about 1000 pm.
[0222] While tissue webs, and tissue products comprising the same, have been described in detail with respect to the specific implementations thereof, it will be appreciated that those skilled in the art, upon attaining an understanding of the foregoing, may readily conceive of alterations to, variations of, and equivalents to these implementations.METHODS
[0223] The present disclosure also provides for a method of making the disclosed herein papermaking fabric. The method comprises interweaving a plurality of machine direction (MD)-oriented warp filaments and a plurality of cross-machine direction (CD)-oriented shute filaments to form the woven papermaking fabric having a machine contacting surface and opposed web contacting surface, wherein the webcontacting surface comprises: a plurality of CD-oriented protuberances wherein each of the plurality of CD-oriented protuberances is formed by at least one shute filament; a plurality of MD-oriented protuberances formed from two or more warp filaments woven to form a first float above corresponding one or more shute filaments, such that the two or more warp filaments in each of the plurality of MD- oriented protuberances are spaced apart wherein the plurality of CD-oriented protuberances and the plurality of MD-oriented protuberances are arranged to form a plurality of recesses, each recess having two opposite edges in the machine direction and two opposite edges in the cross-machine direction, and a floor, wherein each of the plurality of recesses has a depth of 0.3 mm or greater, and wherein the floor defines a bottom plane, wherein two adjacent along the CD axis MD-oriented protuberances and two adjacent along MD axis CD-oriented protuberances form each recess, and an outermost top surface of the web contacting surface is substantially flat. Any of the disclosed herein weave patterns can be used to form the fabric.
[0224] The present disclosure also provides for methods of making a tissue web. The methods comprise forming an aqueous suspension of fibers; depositing the aqueous suspension of fibers onto a forming fabric traveling at a rate of speed to form a wet web; dewatering the web to a consistency of fibers of about 20 percent or greater based on the dry weight of the fibers; transferring the web to a through-air drying fabric defining a plurality of discrete recesses having a depth about 0.30 to about 1 .5 mm, each recess defined by two adjacent machine-direction oriented protuberances and two adjacent cross-direction oriented protuberances in two adjacent rows; and through-air drying the web to form a tissue product, wherein the tissue product has two plies of the through-air dried web, and the tissue product has a plurality of discrete dome-shaped protrusions, each protrusion having a length:width ratio of 1 :1 to 4:1 , a footprint area protrusions covering at least about 15% of a total footprint area of the first surface and a Stiffness Index of about 10 or less. The tissue web is not embossed. In some implementations, the average TS750 value is about 50 or less.
[0225] Although several aspects of the disclosure have been disclosed in the foregoing specification, it is understood by those skilled in the art that many modifications and other aspects of the disclosure will come to mind to which thedisclosure pertains, having the benefit of the teaching presented in the foregoing description and associated drawings. Thus, it is understood that the disclosure is not limited to the specific aspects disclosed hereinabove and that many modifications and other aspects are intended to be included within the scope of the appended claims. Moreover, although specific terms are employed herein, as well as in the claims which follow, they are used only in a generic and descriptive sense and not for the purposes of limiting the described disclosure nor the claims which follow. Therefore, we claim as our disclosure all that comes within the scope and spirit of these claims.
Claims
CLAIMS1 . A multi-ply tissue product comprising two or more through-air dried tissue plies, the tissue product having a first surface and a second surface, wherein the first and second surfaces are outer surfaces of the tissue product, at least the first surface comprising a three-dimensional surface topography, the surface topography comprising a plurality of discrete dome-shaped protrusions extending outwardly from the first surface, each protrusion having a length :width ratio of 1 :1 to 4:1 , wherein a footprint area of the protrusions covers at least about 15% of a total footprint area of the first surface and the tissue product has a Stiffness Index of about 10 or less.
2. The tissue product of claim 1 , wherein the discrete dome-shaped protrusions are molded by recesses defined in a through-air drying fabric.
3. The tissue product of claim 1 , wherein the two or more through-air dried tissue plies are uncreped.
4. The tissue product of claim 1 , wherein a length is measured in a machine direction and a width is measured in a cross-machine direction, and the protrusions are spaced apart from each other on center in each row in the cross-machine direction about 3 mm to about 6 mm.
5. The tissue product of claim 1 , wherein the discrete dome-shaped protrusions are arranged in rows oriented in a cross-machine direction, wherein protrusions in adjacent rows are offset from each other by at least 2 mm as measured in a machine direction from centers of protrusions in each row.
6. The tissue product of claim 5, wherein protrusions in adjacent rows are spaced apart from each other on center in the cross-machine direction by about 1 mm to about 3 mm.
7. The tissue product of claim 1 , wherein the footprint area of the protrusions covers about 45% to about 65% of the total footprint area of the first surface.
8. The tissue product of claim 1 , wherein a height of each protrusion is about 0.3 mm to about 1 .0 mm.
9. The tissue product of claim 1 , wherein the second surface of the tissue product comprises a plurality of discrete dome-shaped protrusions that extend outwardly from the second surface.
10. The tissue product of claim 9 having a basis weight of at least about 30 grams per square meter (gsm) and a sheet bulk of about 15 cc / g to about 18 cc / g.11 . The tissue product of claim 9 having a geometric mean slope (GM Slope) less than or equal to about 10 kg and an average geometric mean tensile (GMT) strength of about 1000 to about 1600 g / 3”.
12. The tissue product of claim 9 having an average TS750 value of about 30 to about 50.
13. The tissue product of claim 12 having an average TS750 value of about 40 to about 50.
14. The tissue product of claim 1 wherein the first and second surfaces are substantially free from embossments.
15. The tissue product of claim 1 having a Stiffness Index from about 3 to about10.
16. The tissue product of claim 1 having a GM Slope from about 5 kg to about 10 kg.
17. The tissue product of claim 1 having an average TS750 value of about 50 or less.
18. A method of making a tissue product comprising: forming an aqueous suspension of fibers; depositing the aqueous suspension of fibers onto a forming fabric traveling at a rate of speed to form a wet web; dewatering the web to a consistency of fibers of about 20 percent or greater based on a dry weight of the fibers; transferring the web to a through-air drying fabric defining a plurality of discrete recesses having a depth of about 0.30 mm to about 1 .5 mm, each recess defined by two adjacent machine-direction oriented protuberances and two adjacent cross-direction oriented protuberances in two adjacent rows; and through-air drying the web to form a tissue product, wherein the tissue product has two plies of the through-air dried web, and at least one outer surface of the tissue product has a plurality of discrete dome-shaped protrusions extending therefrom, each protrusion having a length:width ratio of 1 :1 to 4:1 , wherein a footprint area of the protrusions covers at least about 15% of a total footprint area of the at least one outer surface and an average TS750 value of about 50 or less.
19. The method of claim 18, wherein the tissue product is not embossed.
20. The method of claim 18, wherein the average TS750 value is about 30 to about 50.21 . The method of claim 20, wherein the tissue product has an average TS750 value of about 40 to about 50.
22. The method of claim 18, wherein the tissue product has a Stiffness Index of about 10 or less.