Embossing roll containing oblique-shaped embossing elements and process for using same

Abstract

An embossing roll is disclosed that includes embossing protuberances with an oblique shape. The embossing protuberances can be used to increase caliper without decreasing strength. Alternatively, the embossing protuberances can be used to increase softness by decreasing strength in a controlled manner.

Description

[0001] EMBOSSING ROLL CONTAINING OBLIQUE-SHAPED EMBOSSING ELEMENTS AND PROCESS FOR USING SAME

[0002] CROSS-REFERENCE TO RELATED APPLICATION

[0003] The present application is related and has right of priority to U.S. Provisional Patent Application No. 63 / 556,452 filed on February 2, 2024, which is incorporated by reference in its entireties for all purposes.

[0004] BACKGROUND

[0005] Consumer tissue products such as facial tissue, bath tissue and paper wipers are generally used to absorb liquids and fluids. Such paper products are predominantly formed of cellulosic papermaking fibers by manufacturing techniques designed specifically to produce several important properties. For example, the products should have good bulk, a soft feel, and should be highly absorbent. Further, the products should also have a pleasant aesthetic appearance and should be resilient against deterioration in the environment in which they are used.

[0006] In the past, many attempts have been made to enhance certain physical properties of such products. For instance, to enhance the aesthetic appearance, a decorative paper product has been created by embossing a pattern onto one or both sides of the paper web during manufacturing. This standard mechanical embossing resulted in the deformation or breaking of fibers in an attempt to physically press the pattern into the web. Embossing patterns into tissue webs typically reduce the strength of the web.

[0007] In some embodiments, those skilled in the art have used embossing to increase the thickness of the tissue product, particularly bath tissue. For instance, embossing patterns have been used in order to increase the thickness of multi-ply products in order to improve softness, tactile feel, and roll bulk. Conventional embossing technologies, however, such as double embossed random lamination (DERL), double embosser synchronizer lamination (DESL), or point-to-point embossing, have limits on the ability to generate volume at acceptable levels of basesheet degradation.

[0008] In other embodiments, the embossed patterns formed into a tissue product are not well defined and fade as the paper product is aged. For instance, uncreped, through-air dried tissue webs are not always amenable to receiving embossing patterns.

[0009] Some tissue webs, such as uncreped, through-air dried webs, have relatively high strength properties and using an embossing technique that actually causes strength degradation may be desired in order to increase softness or to improve the appearance of the embossed pattern.

[0010] Controlling strength degradation while producing a visual pattern, however, has been challenging. In view of the above, a need currently exists for an embossing process in one aspect that is capable of not only creating decorative patterns into tissue products but also enhances bulk without severe degradation in strength. A need also exists, in another aspect, for an embossing process that can create a decorative embossing pattern into hard to emboss tissue webs and / or can increase the softness of such webs.

[0011] SUMMARY

[0012] In general, the present disclosure is directed to a process for producing embossed tissue products having enhanced bulk, a soft feel, and various other properties. In one aspect, for instance, the process and system of the present disclosure can be used to dramatically enhance softness and / or the caliper of a tissue sheet with minimum strength degradation. In another aspect, the process and system of the present disclosure can be used to emboss a pattern into a tissue sheet that causes strength degradation and / or produces a visually appealing pattern that is distinct and does not fade over time. The present disclosure is also directed to tissue products made from the process.

[0013] In one embodiment, the present disclosure is directed to an embossing roll for embossing nonwoven webs, such as tissue webs. The embossing roll includes a plurality of embossing protuberances that extend from a surface of the embossing roll. Each embossing protuberance includes a base portion adjacent the surface of the embossing roll and a raised distal portion. Each base portion and distal portion has a cross-sectional shape defining a first axis of symmetry and a second axis of symmetry, wherein the first axis of symmetry and the second axis of symmetry intersect one another to form a center point on each respective base portion and distal portion. The center point of each base portion cross-sectional shape and each corresponding center point of the distal portion cross-sectional shape are not aligned with respect to a vertical axis that is perpendicular to the surface of the embossing roll and intersects the center point of the base portion cross-sectional shape. In one aspect, in order to locate the center point for each base portion and distal portion, the first axis of symmetry can be perpendicular to the second axis of symmetry. For instance, the cross-sectional shape of the distal portion and the cross-sectional shape of the base portion can both be circular. In one aspect, each embossing protuberance has an oblique shape.

[0014] The embossing protuberances can be positioned on the embossing roll based upon a direction of rotation of the roll. For instance, in one embodiment, the embossing protuberances can have a leading vertical edge and a trailing vertical edge. The leading vertical edge can have an angle with a vertical axis that is perpendicular to the surface of the embossing roll and the trailing vertical edge can also have an angle with a vertical axis that is perpendicular to the surface of the embossing roll. In one aspect, the angle of the leading vertical edge can be smaller than the angle of the trailing vertical edge. In this embodiment, the embossing roll can be used to dramatically increase the caliper of a tissue web being embossed without any significant deterioration in strength.

[0015] Alternatively, the direction of rotation of the embossing roll can be reversed such that the angle of the leading vertical edge can be greater than the angle of the trailing vertical edge. In this aspect, the embossing roll is well suited for creating unique visual patterns in hard to emboss tissue webs and / or can be used to cause controlled strength degradation that may improve other properties of the tissue web, such as softness.

[0016] In one aspect, the leading vertical edge can have an angle (when smaller than the trailing vertical edge) of from about 28° to about 68°, such as from about 30° to about 65°, such as from about 45° to about 60°. Alternatively, the leading vertical edge can have an angle (when greater than the trailing vertical edge) of from about 46° to about 90°, such as from about 50° to about 80°, such as from about 60° to about 70°.

[0017] The embossing protuberances, in one aspect, can have a height of from about 0.5 mm to about 2 mm, such as from about 0.8 mm to about 1 .8 mm, such as from about 0.9 mm to about 1 .5 mm. The distal portion of each embossing protuberance, in one aspect, can have a diameter (best fit) of from about 0.2 mm to about 1 mm, such as from about 0.3 mm to about 0.9 mm, such as from about 0.4 mm to about 0.8 mm. The distance between the vertical axis that intersects the center point of the cross-sectional shape of the distal portion and the vertical axis that intersects the center point of the cross-sectional shape of the base portion can be from about 0.05 mm to about 1 mm, such as from about 0.1 mm to about 0.5 mm, such as from about 0.2 mm to about 0.5 mm, such as from about 0.25 mm to about 0.5 mm.

[0018] The embossing protuberances can be placed on the surface of the embossing roll according to a pattern. The embossing roll can include only the embossing protuberances or can include the embossing protuberances in combination with other embossing elements, such as decorative shapes. In one aspect, the embossing protuberances can be present on the surface of the embossing roll at a density of greater than about 5 embossing protuberances, such as greater than about 20 embossing protuberances, such as greater than about 50 embossing protuberances, such as greater than about 70 embossing protuberances, such as greater than about 100 embossing protuberances, such as greater than about 150 embossing protuberances, such as greater than about 200 embossing protuberances, such as greater than about 250 embossing protuberances, such as greater than about 300 embossing protuberances, such as greater than about 350 embossing protuberances, such as greater than about 400 embossing protuberances, such as greater than about 450 embossing protuberances, such as greater than about 500 embossing protuberances, such as greater than about 550 embossing protuberances, such as greater than about 600 embossing protuberances, such as greater than about 650 embossing protuberances, such as greater than about 700 embossing protuberances, such as greater than about 750 embossing protuberances, such as greater than about 800 embossing protuberances, such as greater than about 850 embossing protuberances, such as greater than about 900 embossing protuberances, such as greater than about 950 embossing protuberances, such as greater than about 1 ,000 embossing protuberances, such as greater than about 1 ,200 embossing protuberances, such as greater than about 1 ,500 embossing protuberances, such as greater than about 1 ,700 embossing protuberances, such as greater than about 2,000 embossing protuberances, such as greater than about 2,200 embossing protuberances, such as greater than about 2,500 embossing protuberances, such as greater than about 2,700 embossing protuberances, such as greater than about 3,000 embossing protuberances, such as greater than about 3,200 embossing protuberances, such as greater than about 3,500 embossing protuberances, such as greater than about 3,700 embossing protuberances, such as greater than about 4,000 embossing protuberances, such as greater than about 4,200 embossing protuberances, such as greater than about 4,500 embossing protuberances, such as greater than about 4,700 embossing protuberances, such as greater than about 5,000 embossing protuberances over an area of 100 cm2. The density of the embossing protuberances over an area of 100 cm2is generally less than about 15,000 embossing protuberances, such as less than about 12,000 embossing protuberances, such as less than about 10,000 embossing protuberances, such as less than about 8,000 embossing protuberances, such as less than about 6,000 embossing protuberances, such as less than about 5,000 embossing protuberances, such as less than about 4,000 embossing protuberances, such as less than about 3,000 embossing protuberances, such as less than about 2,000 embossing protuberances, such as less than about 1 ,000 embossing protuberances, such as less than about 900 embossing protuberances, such as less than about 800 embossing protuberances, such as less than about 700 embossing protuberances, such as less than about 600 embossing protuberances, such as less than about 500 embossing protuberances, such as less than about 400 embossing protuberances, such as less than about 300 embossing protuberances.

[0019] The pattern of the embossing protuberances on the surface of the embossing roll can vary depending upon the particular application. In one embodiment, the embossing protuberances can have a relatively high density and be uniformly spaced over the entire surface of the embossing roll. Alternatively, the embossing protuberances may form line structures on the surface of the embossing roll. Each line structure can be spaced from an adjacent line structure. The line structures can be linear or curvilinear. In one embodiment, the line structures can have a wave-like shape.

[0020] The present disclosure is also directed to a process for embossing a tissue ply or sheet. The process can include feeding a tissue ply through a nip formed between the embossing roll as described above and a counter roll in order to emboss the tissue ply according to a pattern of embossing protuberances located on the surface of the embossing roll.

[0021] In one embodiment, the process can be used to emboss a single ply tissue web for producing a single ply product. Alternatively, a tissue ply can be embossed and then attached to a second tissue ply for creating a multi-ply product. The embossed tissue web can have a sheet bulk of from about 8 cc / g to about 20 cc / g, such as from about 10 cc / g to about 14 cc / g. Embossing a tissue web in accordance with the present disclosure can, in one aspect, dramatically increase the thickness of the tissue web. For instance, the tissue web can increase in caliper by greater than about 10%, such as greater than about 15%, such as greater than about 20%. The tissue product can have a basis weight of from about 14 gsm to about 80 gsm, such as from about 14 gsm to about 60 gsm, such as from about 14 gsm to about 30 gsm.

[0022] In one aspect, the tissue web emboss can be an uncreped through-air dried sheet for forming a single ply product. Alternatively, a multi-ply product can be formed in which at least one of the plies comprises a creped tissue web.

[0023] The present disclosure is also directed to tissue products made according to the process described above. The tissue product of the present disclosure can be spirally wound into rolls with periodic lines of perforation for producing bath tissues and paper towels. Alternatively, the tissue product can be cut into individual sheets and marketed as interfolded stacks.

[0024] Other features and aspects of the present disclosure are discussed in greater detail below.

[0025] BRIEF DESCRIPTION OF THE DRAWINGS

[0026] A full and enabling disclosure of the present disclosure is set forth more particularly in the remainder of the specification, including reference to the accompanying figures, in which:

[0027] Figure 1 is a perspective view of one embodiment of an embossing roll made in accordance with the present disclosure;

[0028] Figure 2 is a perspective view of one embodiment of an embossing protuberance that form raised elements on the embossing roll illustrated in Figure 1 ;

[0029] Figure 3 is a perspective view of another embodiment of an embossing protuberance in accordance with the present disclosure;

[0030] Figure 4 is a perspective view of another embodiment of an embossing protuberance in accordance with the present disclosure;

[0031] Figure 5 is a perspective view of another embodiment of an embossing protuberance in accordance with the present disclosure;

[0032] Figure 6 is a partial cross-sectional view of the embossing roll illustrated in Figure 1 ;

[0033] Figure 7 is a plan view of one embodiment of an embossing pattern that may be applied to the embossing roll illustrated in Figure 1 containing the embossing protuberances as shown in Figure 2;

[0034] Figure 8 is a cross-sectional view of one embodiment of an embossing process in accordance with the present disclosure;

[0035] Figure 9 is a cross-sectional view of another embodiment of an embossing process in accordance with the present disclosure;

[0036] Figure 10 is a perspective view of one embodiment of a spirally wound roll of tissue product made in accordance with the present disclosure; and

[0037] Figure 11 is a perspective view of an interfolded stack of individual sheets of a tissue product made in accordance with the present disclosure.

[0038] Repeat use of reference characters in the present specification and drawings is intended to represent the same or analogous features or elements of the present invention.

[0039] DEFINITIONS

[0040] As used herein the term “machine direction” or “MD” generally refers to the direction in which a tissue web or product is produced. The term “cross-machine direction" or “CD” refers to the direction perpendicular to the machine direction.

[0041] As used herein the term “Fibrous Structure” refers to a structure comprising a plurality of elongated particulate having a length to diameter ratio greater than about 10 such as, for example, papermaking fibers and more particularly pulp fibers, including both wood and non-wood pulp fibers, and synthetic staple fibers. A non-limiting example of a fibrous structure is a tissue web comprising pulp fibers.

[0042] As used herein the term “Tissue Web” or “Tissue Ply” refers to a fibrous structure provided in sheet form and being suitable for forming a tissue product.

[0043] 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, and other similar products. Tissue products may comprise one, two, three or more plies.

[0044] As used herein the term “Pattern” generally refers to the arrangement of one or more design elements. Within a given pattern the design elements may be the same or may be different, further the design elements may be the same relative size or may be different sizes. For example, in one embodiment, a single design element may be repeated in a pattern, but the size of the design element may be different from one design element to the next within the pattern.

[0045] As used herein, the term “Embossing Pattern or Design” generally refers to a decorative shape disposed across at least one dimension of a fibrous structure surface, the pattern may comprise a line element, discrete elements or other shapes. The embossing pattern comprises a portion of the fibrous structure lying out of plane with the surface plane of the fibrous structure. In general, the embossing pattern results from embossing the fibrous structure resulting in protrusions having a z- directional elevation on one side of the fibrous structure and raised areas on the opposite side of the fibrous structure.

[0046] As used herein the term “Line Structure" refers to an element, such as an embossing element, in the shape of a line, which may be continuous or discontinuous, such as discrete or interrupted. The line element may be of any suitable shape such as straight, bent, kinked, curled, curvilinear, serpentine, sinusoidal, and mixtures thereof that may form a regular or irregular, periodic or nonperiodic lattice work of structures wherein the line element exhibits a length along its path of at least 10 mm. In one example, the line element may comprise a plurality of discrete elements, such as dots and / or dashes for example, that are oriented together to form a line element.

[0047] As used herein the term “Continuous Embossment” or “Continuous Line Embossments” refers to an element, such as an embossing element, disposed on a fibrous structure that extends without interruption throughout one dimension of the fibrous structure.

[0048] As used herein the term “Discrete Elements or Shapes" refers to an element, such as an embossing element, disposed on a fibrous structure that does not extend continuously in any dimension of the fibrous structure.

[0049] As used herein the term “Basis Weight” (BW) 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 using TAPPI test method T-220. While basis weight may be varied, tissue products prepared according to the present invention generally have a basis weight greater than about 10 gsm, such as from about 10 to about 150 gsm and more preferably from about 30 to about 60 gsm.

[0050] As used herein, the term “caliper” is the representative thickness of a single 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 TAPPI test method T402 using a ProGage 500 Thickness Tester (Thwing-Albert Instrument Company, West Berlin, N.J.). The micrometer has an anvil diameter of 2.22 inches (56.4 mm) and an anvil pressure of 132 grams per square inch (per 6.45 square centimeters) (2.0 kPa).

[0051] As used herein the term “Sheet Bulk” refers to the quotient of the caliper (generally having units of pm) divided by the bone dry basis weight (generally having units of gsm). The resulting sheet bulk is expressed in cubic centimeters per gram (cc / g). While sheet bulk may vary depending on any one of a number of factors, tissue products prepared according to the present invention may have a sheet bulk greater than about 10.0 cc / g.

[0052] As used herein the term “dot embossment” or “dot emboss element” means an embossment or an embossing element that exhibits an aspect ratio of about 1 :1 .25 or less, such as an aspect ratio from about 1 .0 to about 1.25. Non-limiting examples of dot embossments are embossments having a circular, oval, square, or triangular cross-sectional shape.

[0053] DETAILED DESCRIPTION

[0054] It is to be understood by one of ordinary skill in the art that the present discussion is a description of exemplary embodiments only and is not intended as limiting the broader aspects of the present disclosure.

[0055] In general, the present disclosure is directed to an embossing process for tissue webs, an embossing roll and system for embossing tissue webs, and to tissue products made from the process. In one aspect, the embossing roll of the present disclosure can comprise a plurality of embossing protuberances. The embossing protuberances have a base portion and a distal end portion. The base portions and the distal end portions have a cross-sectional shape defined by first and second axis of symmetry, wherein the first and second axis of symmetry intersect one another to form a center point. In accordance with the present disclosure, the center point of the base portion cross-sectional shape and the center point of the distal end portion cross-sectional shape are not vertically aligned with one another. For instance, the embossing protuberances can display an oblique shape, such that the embossing protuberances have a top surface center of axis that is not aligned with the base portion center of axis.

[0056] The oblique-shaped embossing protuberances thus have non-uniform angles measured from a vertical axis that extend from the surface of the embossing roller to the top surface of each embossing protuberance. In one aspect, the oblique-shaped embossing protuberances include a vertical edge having a small angle that is positioned directly opposite to a vertical edge having a larger angle.

[0057] The embossing protuberances can be positioned on an embossing roll such that the vertical edge with the smallest angle and the vertical edge with the largest angle are in alignment with the direction of rotation of the roll. In one embodiment, when the vertical edge of the oblique-shaped embossing protuberances having the smallest angle is the leading edge of the embossing protuberance during rotation, the embossing process is designed to dramatically increase the caliper of individual tissue plies in a manner that not only enhances the bulk of the final product but also minimizes strength degradation of the tissue ply.

[0058] In an alternative embodiment, rotation of the roll can be reversed such that the vertical edge displaying the largest angle can be the leading edge of the embossing protuberances. In this embodiment, the embossing process is well suited to embossing visual designs into tissue plies that do not fade over time. Having the largest vertical angle be the leading edge of the embossing protuberances can also cause strength degradation of the tissue ply in a controlled manner that can optimize other properties of the tissue web, such as strength.

[0059] Thus, embossing rolls made according to the present disclosure can be multi-functional simply by changing the direction of rotation.

[0060] In general, any suitable tissue ply can be embossed in accordance with the present disclosure. The tissue ply, for instance, can comprise any suitable nonwoven material that can be made through a wetlaid process, air-laying, or through a foam forming process. The tissue ply generally contains cellulose fibers, particularly cellulose pulp fibers. For instance, the tissue ply can contain greater than about 40% by weight, such as greater than about 50% by weight, such as greater than about 60% by weight, such as greater than about 70% by weight cellulose pulp fibers. The multiply products in accordance with the present disclosure can be used to produce numerous products including bath tissue, facial tissue, table napkins, paper towels, and the like. The tissue product can contain a single tissue ply or at least two tissue plies, such as three tissue plies or four tissue plies.

[0061] The embossed tissue products of the present invention generally have a total product basis weight of at least about 14 gsm, such as at least about 20 gsm, such as at least about 30 gsm, such as at least about 35 gsm, such as at least about 40 gsm, such as at least about 45 gsm and less than about 75 gsm. In certain instances, the product basis weight may range from about 14 gsm to about 70 gsm, such as from about 20 gsm to about 65 gsm, such as about 30 gsm to about 60 gsm. Single ply tissue products made according to the present disclosure can generally have a basis weight of from about 14 gsm to about 35 gsm, while multi-ply tissue products can have a basis weight of from about 20 gsm to about 70 gsm. The basis weight of one tissue ply is generally greater than about 14 gsm, such as greater than about 18 gsm, such as greater than about 22 gsm, such as greater than about 26 gsm, and less than about 40 gsm, such as less than about 35 gsm, such as less than about 30 gsm.

[0062] Referring to FIGS. 1 and 2, one embodiment of an embossing roll 26 made in accordance with the present disclosure illustrating a pattern 14 of embossing protuberances 18. An enlarged view of a single embossing protuberance is illustrated in FIG. 2.

[0063] As shown in FIG. 1 , the embossing protuberances 18 form a pattern 14 on a surface 28 of the embossing roll 26. The embossing protuberances 18, for instance, extend from the surface 28 of the embossing roll 26 and form raised embossing elements.

[0064] In accordance with the present disclosure, the embossing protuberances 18 have an oblique shape such that the top surface of the embossing protuberance is off center and not aligned with the bottom surface or base portion of the embossing protuberance. For instance, referring to FIG. 2, the embossing protuberance 18 includes a base portion 16 that is attached to or is placed adjacent to the surface 28 of the embossing roll 26. The base portion 16 is spaced from a distal portion or top surface 20. As shown in FIG. 2, the base portion 16 can include a geometric center 30 while the distal portion 20 can include a geometric center 32. The center point 30 of the base portion 16 can be located along a vertical axis 34 that is perpendicular to the surface 28 of the embossing roll 26. Similarly, the center point 32 of the distal portion or top surface 20 can intersect a vertical axis 36 that is also perpendicular to the surface 28 of the embossing roll 26. As illustrated in FIG. 2, the vertical axis 34 is spaced from the vertical axis 36 which illustrates how the center of the base portion 16 is not in alignment with the center of the distal portion 20.

[0065] In the embodiment illustrated in FIG. 2, the base portion 16 has a circular-shaped crosssection. The center point of the base portion 16 can be located using well known geometric principles. For instance, the base portion 16 can include a first axis of symmetry 38 that is perpendicular to and intersects with a second axis of symmetry 40. The first axis of symmetry 38 and the second axis of symmetry 40 are both diameters of the base portion 16 when having a circular shape. The first axis of symmetry 38 intersects the second axis of symmetry 40 at the center point 30 of the cross-sectional shape of the base portion 16. Similarly, the distal portion or top surface 20 includes a first axis of symmetry 42 that is perpendicular to a second axis of symmetry 44. The first axis of symmetry 42 intersects the second axis of symmetry 44 at the center point 32.

[0066] Due to the oblique shape of the embossing protuberance 18, the side walls of each protuberance can vary depending upon position. For instance, each side wall of the embossing protuberance 18 can have a different length and can form a different angle of relationship with respect to the surface of the base portion 16 or to the surface 28 of the embossing roll 26. As shown in FIG. 2, for instance, the embossing protuberance 18 can include a vertical edge 22 opposite (spaced 180°) from a vertical edge 24. The vertical edge 22, for instance, can comprise a side wall with the shortest distance measured from the base portion 16 to the distal portion 20 and can have the largest angle 46 measured from the surface of the base portion 16. The vertical edge 24, on the other hand, can have the longest distance from the base portion 16 to the distal portion 20 and can form the smallest angle measured from the surface of the base portion 16.

[0067] For example, in one aspect, the vertical edge or side wall 22 can form an angle with the surface of the base portion 16 of from about 46° to about 90°. For instance, the angle 46 can be greater than about 50°, such as greater than about 55°, such as greater than about 60°, such as greater than about 65°, such as greater than about 70°, such as greater than about 75°, such as greater than about 80°, and less than about 85°, such as less than about 80°, such as less than about 75°, such as less than about 70°, such as less than about 60°. The angle 48 formed between the surface of the base portion 16 and the vertical edge or side wall 24, on the other hand, can be less than about 68°, such as less than about 65°, such as less than about 60°, such as less than about 55°, such as less than about 50°, such as less than about 45°. The angle 48 can be greater than about 25°, such as greater than about 28°, such as greater than about 30°, such as greater than about 35°, such as greater than about 40°, such as greater than about 45°.

[0068] Each embossing protuberance 18 can have any suitable size and shape depending upon various factors including the characteristics of the tissue sheet being embossed, the type of tissue product being formed, the embossing pattern, and the like. In one aspect, each embossing protuberance 18 can comprise a discrete embossing element on the surface 28 of the embossing roll 26. In one aspect, each embossing protuberance 18 can comprise a dot embossment.

[0069] In one aspect, each embossing protuberance 18 can have a height (distance from the base portion 16 to the distal portion 20) of greater than about 0.5 mm, such as greater than about 0.7 mm, such as greater than about 0.9 mm, such as greater than about 1.1 mm, such as greater than about 1 .3 mm, such as greater than about 1 .5 mm, such as greater than about 1 .7 mm. The height of the embossing protuberances 18 is generally less than about 5 mm, such as less than about 3 mm, such as less than about 2 mm, such as less than about 1 .8 mm, such as less than about 1 .5 mm, such as less than about 1 .3 mm. When the distal portion 20 has a circular cross-sectional shape as shown in FIG. 2, the distal portion 20 can have a diameter of generally greater than about 0.2 mm, such as greater than about 0.3 mm, such as greater than about 0.4 mm, such as greater than about 0.5 mm, and less than about 2 mm, such as less than about 1 mm, such as less than about 0.9 mm, such as less than about 0.8 mm.

[0070] The area of the distal portion 20 of the embossing protuberances (whether circular or some other shape) can generally be less than about 7 mm2, such as less than about 4 mm2, such as less than about 3 mm2, such as less than about 2 mm2, such as less than about 1 mm2, such as less than about 0.8 mm2, such as less than about 0.7 mm2, such as less than about 0.6 mm2, such as less than about 0.5 mm2, such as less than about 0.4 mm2. The area of the distal portion of each embossing protuberance can generally be greater than about 0.01 mm2, such as greater than about 0.03 mm2, such as greater than about 0.05 mm2, such as greater than about 0.07 mm2, such as greater than about 0.09 mm2, such as greater than about 0 12 mm2, such as greater than about 0 15 mm2, such as greater than about 0.17 mm2, such as greater than about 0.2 mm2.

[0071] As explained above with respect to FIG. 2, the embossing protuberances 18 in accordance with the present disclosure can have an oblique shape in which the center point 30 of the base portion 16 is not in alignment with the center point 32 of the distal portion 20. The distance between the vertical axis 34 that intersects the center point 30 and the vertical axis 36 that intersects the center point 32 can vary depending upon various factors including the relative dimensions of the embossing protuberance 18 and the type of embossing pattern being created. In one aspect, the vertical axis 34 can be spaced from the vertical axis 36 a distance of greater than about 0.05 mm, such as greater than about 0.1 mm, such as greater than about 0.2 mm, such as greater than about 0.25 mm. The distance between the vertical axis 34 and the vertical axis 36 is generally less than about 1 mm, such as less than about 0.5 mm, such as less than about 0.4 mm.

[0072] Referring to FIG. 6, a partial cross-sectional view of the embossing roller 26 is illustrated showing a plurality of cross-sections of the embossing protuberances 18. Each embossing protuberance 18 includes a base portion 16 positioned adjacent to the surface 28 of the embossing roll 26. Each embossing protuberance 18 further includes a distal portion 20 that forms raised areas on the surface of the embossing roll 26. Each embossing protuberance 18 has an oblique shape including a vertical edge or side wall 22 opposite a vertical edge or side wall 24. In the embodiment illustrated in FIG. 6, the vertical edge 22 of each embossing protuberance 18 is linear. In other embodiments, the vertical edges of the side walls can be non-linear and have a curvature.

[0073] The embossing roll 26 can be configured to rotate in a direction 50 or in an opposite direction 52 when contacting and embossing a tissue sheet.

[0074] In one aspect, for instance, the embossing roll 26 can rotate in the direction 50 such that the vertical edge or side wall 24 becomes the leading edge of the embossing protuberance 18 and the vertical edge or side wall 22 becomes the trailing edge. In this embodiment, the leading edge of the embossing protuberance 18 has an angle with respect to the surface of the base portion 16 that is less than the angle of the trailing edge wall. In this configuration, the embossing protuberances 18 and the overall embossing pattern on the embossing roll 26 is designed to dramatically increase the caliper of the embossed tissue sheet without significantly degrading the strength of the tissue sheet in the machine direction. Increasing the caliper of the tissue sheet can, in one aspect, increase bulk and / or increase softness. The embossed tissue sheet also can be embossed with a highly distinctive look or pattern that can increase the overall aesthetics of the product.

[0075] In an alternative embodiment, the embossing roll 26 can be rotated in the opposite direction 52. In this embodiment, the side wall 22 becomes the leading edge of each embossing protuberance 18 and the side wall 24 becomes the trailing edge. In this aspect, the angle of the leading edge with respect to the surface of the base portion 16 is greater than the angle of the trailing edge. In this configuration, the embossing protuberances 18 and the embossing roll 26 are designed to create a visual embossing pattern into a tissue sheet while also decreasing strength, such as in the machine direction, for increasing the softness of the tissue sheet. This configuration, for instance, is particularly well suited for embossing hard to emboss tissue webs that traditionally have not been amenable to embossing processes in which the resulting embossing pattern is visually appealing. For instance, in this aspect, the tissue sheet being embossed can be a single ply uncreped through-air dried tissue sheet. Through the process of the present disclosure, an embossing pattern can be formed into the sheet that does not fade over time and that not only improves the visual appearance of the tissue sheet but also can dramatically improve softness. This configuration is also particularly well suited for embossing tissue sheets with higher basis weights, such as greater than about 35 gsm, such as greater than about 40 gsm, such as greater than about 45 gsm, such as greater than about 50 gsm, such as greater than about 55 gsm, and less than about 70 gsm.

[0076] As illustrated in FIG. 6, the embossing roll 26 of the present disclosure is multi-functional. The embossing roll 26 including the embossing protuberances 18 of the present disclosure can, in one aspect, increase caliper without degrading strength or, alternatively, can decrease strength of a tissue sheet in a controlled way that improves softness.

[0077] The embossing protuberances 18 can form any suitable pattern on the embossing roll 26. The embossing pattern, for instance, can include a high density of embossing protuberances or can include a relatively low density of embossing protuberances to form a pattern. The embossing protuberances can uniformly cover the surface of the embossing roll as shown in FIG. 1 . Alternatively, the embossing protuberances 18 can form spaced apart line structures as shown in FIG. 7.

[0078] For example, in FIG. 1 , the embossing protuberances 18 form an embossing pattern on the embossing roll 26. The embossing pattern comprises a continuous and regular pattern of dot embossments comprised of the embossing protuberances 18, which can be micro-embossments in one embodiment. For instance, the embossing protuberances can have an aspect ratio of from about 1 to about 1 .25, such as from about 1 to about 1.1. The embossing protuberances may be homogeneous in size and shape or can vary within a given pattern. In the embossing pattern shown in FIG. 1 , the embossing protuberances 18 are all of a single size. The embossing protuberances as shown in FIG. 1 are uniformly spaced apart and can display an embossment density of greater than about 1 ,000 embossing protuberances per 100 cm2, such as greater than about 2,000 embossing protuberances per 100 cm2, such as greater than about 2,500 embossing protuberances per 100 cm2, such as greater than 3,000 embossing protuberances per 100 cm2, such as greater than about 3,500 embossing protuberances per 100 cm2, such as greater than about 4,000 embossing protuberances per 100 cm2, such as greater than about 4,500 embossing protuberances per 100 cm2, such as greater than about 5,000 embossing protuberances per 100 cm2, and generally less than about 100,000 embossing protuberances per 100 cm2, such as less than about 80,000 embossing protuberances per 100 cm2, such as less than about 60,000 embossing protuberances per 100 cm2.

[0079] Referring to FIG. 7, a portion of an embossing roll 26 is shown including an embossing roll surface 28. On the embossing roll surface 28 are a pattern of embossing protuberances 18 in accordance with the present disclosure. In this embodiment, the embossing protuberances 18 comprise line structures that are discontinuous meaning that the line structures are made from discrete embossments or dot embossments. In this embodiment, the line structures are curvilinear and have a wave-like shape. Alternatively, however, the line structures can be linear. The line structures can extend in the cross-direction and can be spaced from one another such that they do not intersect. The embossing protuberances 18 can be spaced apart within each line structure (center point of distal portion to center point of distal portion of adjacent embossing protuberance) of greater than about 0.5 mm, such as greater than about 1 mm, such as greater than about 1 .1 mm, such as greater than about 1 .2 mm, such as greater than about 1 .3 mm, such as greater than about 1 .4 mm, such as greater than about 1 5 mm, and less than about 4 mm, such as less than about 3 mm, such as less than about 2 mm, such as less than about 1 .8 mm. The distance between each line structure can vary greatly depending upon the desired look or properties that are to be obtained. The line structures, for instance, can be spaced close together, can be spaced relatively far apart, or can include a combination of both as shown in FIG. 7. The line structures are generally spaced a distance of greater than about 1 mm apart, such as greater than about 1 .5 mm apart, such as greater than about 2 mm apart, such as greater than about 3 mm apart, such as greater than about 4 mm apart, such as greater than about 5 mm apart, such as greater than about 6 mm apart. Alternatively, the line structures can be spaced greater than about 15 mm apart, such as greater than about 20 mm apart, such as greater than about 30 mm apart. The line structures are generally spaced less than about 10,000 mm apart, such as less than about 1 ,000 mm apart.

[0080] The embossing roll can include a pattern of only discrete embossing elements as shown in FIG. 1 . Alternatively, the embossing pattern can further include continuous line embossments. The line embossments can overlap with the pattern of the embossing protuberances 18. The continuous line embossments can be used to form decorative patterns or images into a tissue product. For instance, as shown in FIG. 7, the embossing pattern includes continuous line embossments 54 that are used to produce an image, such as a puppy.

[0081] In FIG. 2, the center point 30 of the base portion 16 and the center point 32 of the distal portion 20 of the embossing protuberance 18 are located along the same diameter of the base portion 20 and thus are only offset in the x-direction. It should be understood, however, that the center point 32 can be offset from the center point 30 in an x-direction and in a y-direction. For instance, referring to FIG. 3 an alternative embodiment of an embossing protuberance 18 is shown in accordance with the present disclosure. Like reference numerals have been used to indicate similar elements. The embossing protuberance 18 illustrated in FIG. 3 includes a base portion 16 spaced from a distal portion 20. The base portion 16 includes a center point 30 that is not in vertical alignment with a center point 32 of the distal portion 20. More particularly, the center point 30 is offset from the center point 32 in the x-direction and in the y-direction .

[0082] In FIG. 2, the base portion 16 and the distal portion 20 of the embossing protuberance 18 are circular. It should be understood, however, that the embossing protuberance 18 can have any suitable shape. For instance, the base portion 16 and / or the distal portion 20 can have a cross-section that has an oval shape, that is rectangular, that is triangular, that forms a polygon, or that forms an irregular shape. For instance, referring to FIGS. 4 and 5, alternative embodiments of embossing protuberances 18 are shown in accordance with the present disclosure. Like reference numerals have been used to indicate similar elements. The embossing protuberances 18 illustrated in FIGS. 4 and 5 include a base portion 16 spaced from a distal portion 20. The base portion 16 includes a center point 30 that is not in vertical alignment with a center point 32 of the distal portion 20. Each embossing protuberance can include a vertical edge or surface 22 opposite a vertical edge or surface 24. The vertical edge or surface 24 forms an angle with the surface of the base portion 16 that is less than the angle formed by the vertical edge or surface 22 with the surface of the base portion 16.

[0083] In FIG. 4, the base portion 16 has a rectangular cross-sectional shape and the distal portion 20 has a rectangular cross-sectional shape. In FIG. 5, on the other hand, the base portion 16 has a rectangular cross-sectional shape, while the distal portion 20 has a circular cross-sectional shape.

[0084] The embossing roll 26 as shown in FIG. 1 can be used to emboss all different types of sheet materials, particularly tissue webs. The embossing roll 26 can be used to emboss tissue webs for producing single ply products or multi-ply products. Referring to FIG. 8, for instance, one embodiment of a process for producing a multi-ply tissue product 10 is illustrated. As will be explained in greater detail below, in one aspect, a first tissue ply 12 is embossed in accordance with the present disclosure and then laminated to a second tissue ply 13. An adhesive or moisture can be used to attach the tissue plies together. The adhesive can be, for instance, a starch, a methylcellulose, or a polymer adhesive containing polypropylene, polyisobutylene, a polyurethane, a polyacrylate, a polyvinyl acetate, an ethylene vinyl acetate, or a polyvinyl alcohol.

[0085] As shown in FIG. 8, the first tissue ply 12 is conveyed past a series of idler rollers 122 towards a nip 124 that is located between an embossing roll 26 and a backing roll 128. Prior to entering the nip 124, in one aspect, the first tissue ply 12 can be prewetted with a prewetting solution such as water if desired.

[0086] The first tissue ply 12 is fed into the first nip 124 which can be a heated nip. The nip 124 is formed between the embossing roll 26 and a backing roll 128. The embossing roll 26 includes a pattern of male embossing protuberances 18 that embosses a pattern into the first tissue ply 12. During embossing, the tissue ply 12 can be heated.

[0087] The nip 124 can be heated using any suitable heating means. For instance, the embossing roll 26 can be heated, the backing roll 128 can be heated, or both rolls can be heated. In one aspect, the embossing roll 26 is heated. The nip 124 or the surface of the embossing roll 26, for instance, can be heated to a temperature of greater than about 70°C, such as greater than about 80°C, such as greater than about 90°C, such as greater than about 100°C, such as greater than about 110°C, such as greater than about 120°C, such as greater than about 130°C, such as greater than about 140°C, and less than about 220°C, such as less than about 200°C, such as less than about 190°C, such as less than about 180°C, such as less than about 170°C. In one aspect, the embossing roll 26 can be combined with a heating device that can be housed within the roll for heating by conduction.

[0088] Alternatively, the embossing roll 26 can be heated by radiation and / or convection. As described above, the nip 124 formed between the embossing roll 26 and the backing roll 128 is heated for heating the tissue ply 12 as the tissue ply is embossed.

[0089] The embossing roll 26 is generally a hard and non-deformable roll, such as a steel roll. The backing roll 128 can be a substantially smooth roll that, in one embodiment, can include a covering made of natural or synthetic rubber. The natural or synthetic rubber, for instance, can be polybutadiene or copolymers of ethylene and propylene or the like. In one aspect, the backing roll 128 has a hardness of greater than about 40 Shore A, such as from about 40 Shore A to about 100 Shore A including all increments of 1 Shore A therebetween. For example, in one aspect, the hardness of the backing roll 128 can be from about 50 Shore A to about 70 Shore A.

[0090] After the first tissue ply is embossed, it is laminated to a second tissue ply to form a multi-ply tissue product. The lamination process is carried out with or without the use of an adhesive.

[0091] A joining station may be configured such that the upper steel embossing roll abuts an aqueous or adhesive composition delivery assembly and a marrying roll to further laminate and join the first embossed ply to the second ply to form a multi-ply embossed tissue product according to the present disclosure. In particular, the upper steel embossing roll may abut an aqueous or adhesive composition delivery applicator which distributes a composition onto the embossed ply, particularly the protruding embossments of the embossed ply. After application of the composition, the embossed and wetted ply may be joined to the second ply by a marrying roll, which may be arranged such that it abuts the upper steel embossing roll. In this manner, the upper steel embossing roll and marrying roll may form a nip therebetween through which the plies pass and are joined together to form a multi-ply tissue product.

[0092] For instance, as shown in FIG. 8, the first tissue ply 12 enters the heated nip 124 and is embossed by the embossing roll 26 by the pattern of embossing elements or protuberances 18. Not only is the tissue ply 12 heated in the nip 124 but is also subjected to pressure against the embossing roll 26 for forming an embossing pattern into the tissue ply 12. As shown, in order to form a two-ply tissue product, a second tissue ply 13 is conveyed and pressed into a nip 144 located between a substantially smooth roll 146 which may be made of rubber and a marrying roll 148, which may be a steel roll. The second tissue ply 13 can be adapted to form the bottom ply in the resulting multi-ply tissue product 10 or, alternatively, can be configured to be the top ply. As it is conveyed, the second tissue ply passes through the nip 144 where it is brought into contact with the first tissue ply 12, which now bears the embossing design as a result of being embossed by the embossing roll 26. The first and second plies 12 and 13 are joined together as they pass through the nip 144 to form a multi-ply tissue product 10.

[0093] As shown in FIG. 8, after the first tissue ply passes through the first nip 124 between the embossing roll 26 and the backing roll 128, a bonding unit 152 can apply a bonding solution to the distil ends of protrusions on the opposite surface of the first tissue ply 12 that is in contact with the embossing roll 26. For instance, as the tissue ply 12 is embossed on a first surface, protrusions form on the second surface according to the embossing pattern. In one aspect, the bonding unit 152 is positioned and configured only to apply a bonding solution to the top of the protrusions on the first tissue ply 12.

[0094] In one embodiment, the bonding unit 152 can include a distribution roll and a dosing roll. The bonding solution, which can comprise water or an adhesive is stored in a tank, is collected onto the distribution roll, and subsequently transferred to the dosing roll. The dosing roll contacts the protrusions on the first tissue ply 12 for applying the bonding solution to the tissue ply in a controlled manner.

[0095] It should be understood that the bonding unit 152 represents merely one way of applying the bonding solution to the first tissue ply 12. Various other techniques and methods can be used to apply the bonding solution to the first tissue ply 12. For instance, the bonding solution can be applied to the tissue ply using a gravure roll, through a digital printer, using a knife blade, or spraying the bonding solution onto the tissue ply 12.

[0096] In one aspect, the bonding solution is heated prior to being applied to the tissue ply 12. For instance, the bonding solution can be heated to a temperature of from about 60°C to about 90°C, including all increments of 1°C therebetween. For instance, the bonding solution can be heated to a temperature of greater than about 65°C, such as greater than about 70°C, such as greater than about 75°C, and less than about 85°C.

[0097] The bonding solution is generally applied to the first tissue ply 12 in an amount less than about 6% by weight, such as in an amount less than about 5% by weight, such as in an amount less than about 4% by weight, such as in an amount less than about 3% by weight, such as in an amount less than about 2% by weight, such as in an amount less than about 1% by weight. The bonding solution is applied to the first tissue ply 12 in an amount greater than about 0.1% by weight, such as in an amount greater than about 0.5% by weight, such as in an amount greater than about 1% by weight, such as in an amount greater than about 1 .5% by weight, such as in an amount greater than about 2% by weight.

[0098] As shown in FIG. 8, the embossed first tissue ply 12 with the applied bonding solution advances into the nip 144 and the second ply 13 is attached to the embossed first ply 12 to form the two-ply tissue product 10 which is subsequently spirally wound into a roll (not shown).

[0099] Through the above process, a tissue product 10 can be formed. The tissue product 10 can comprise a two-ply tissue product in which the first ply 12 is the embossed ply that forms the top of the product. The second ply 13, on the other hand, can be a non-embossed ply that remains relatively planar and forms the bottom surface of the product. Alternatively, the second ply 13 can be embossed similar to ply 12 or can be embossed, such as microembossed, with a conventional embossing pattern. In other embodiments, the tissue product 10 can include a third ply and / or a fourth ply.

[0100] Generally, the multi-ply products of the present disclosure are embossed and comprise two or more tissue plies bonded together along a plurality of bonded areas. In certain instances, the bonded areas may correspond to the embossments disposed on the one or more tissue plies. The embossed area, relative to the total area of the ply surface, and in-turn the bonded area, may range from about 2% to about 60%, such as from about 2% to about 30%, such as form about 2% to about 20%.

[0101] In addition to multi-ply tissue products, the embossing roll 26 of the present disclosure can also be used to produce single ply tissue products. For instance, as shown in FIG. 9, one embodiment of a process for embossing a tissue sheet and forming a single ply tissue product 10 is illustrated. As shown, a tissue ply is unwound, fed around guide rolls 122, and fed into a nip 124 created between the embossing roll 26 and a backing roll 128. The embossing roll 26 includes a pattern of embossing protuberances 18 in accordance with the present disclosure. The leading edge and trailing edge of each embossing protuberance 18 can vary depending upon the particular application as described above. The tissue sheet 12 is embossed within the nip 124 and / or in the nip 150 formed between the embossing roll 26 and a marrying roll 148. In this manner, a single ply tissue product 10 is formed that can include a distinctive and aesthetically pleasing embossing pattern. The embossing pattern can be used to improve one or more properties of the tissue sheet 12. The embossing pattern, for instance, can increase the caliper of the tissue sheet 12. Alternatively, the embossing roll 26 can be used to degrade the strength of the tissue sheet 12 in a controlled manner that improves softness.

[0102] In general, any suitable tissue web can be embossed in accordance with the present disclosure and incorporated into the tissue product 10. Bath tissue, facial tissue, paper towels, industrial wipers, and the like can be formed in accordance with the present disclosure. The tissue product 10 can be packaged as individual sheets contained in a dispenser or can be offered to consumers in the form of a spirally wound roll. Tissue products and the tissue plies incorporated into the product can generally have a bulk density of greater than about 3 cc / g, such as greater than about 5 cc / g, such as greater than about 6 cc / g, such as greater than about 7 cc / g, such as greater than about 8 cc / g, such as greater than about 9 cc / g, such as greater than about 10 cc / g, such as greater than about 11 cc / g, such as greater than about 12 cc / g, and generally less than about 20 cc / g.

[0103] Fibers suitable for making tissue webs comprise any natural or synthetic cellulosic fibers including, but not limited to nonwoody fibers, such as cotton, abaca, kenaf, sabai grass, flax, esparto grass, straw, jute hemp, bagasse, milkweed floss fibers, and pineapple leaf fibers; and woody or pulp fibers such as those obtained from deciduous and coniferous trees, including softwood fibers, such as northern and southern softwood kraft fibers; hardwood fibers, such as eucalyptus, maple, birch, and aspen. Pulp fibers can be prepared in high-yield or low-yield forms and can be pulped in any known method, including kraft, sulfite, high-yield pulping methods and other known pulping methods. Fibers prepared from organosolv pulping methods can also be used, including the fibers and methods disclosed in U.S. Pat. No. 4,793,898, issued Dec. 27, 1988 to Laamanen et al.; U.S. Pat. No. 4,594,130, issued Jun. 10, 1986 to Chang et al.; and U.S. Pat. No. 3,585,104. Useful fibers can also be produced by anthraquinone pulping, exemplified by U.S. Pat. No. 5,595,628 issued Jan. 21 , 1997, to Gordon et al.

[0104] A portion of the fibers, such as up to 50% or less by dry weight, or from about 5% to about 30% by dry weight, can be synthetic fibers such as rayon, polyolefin fibers, polyester fibers, bicomponent sheath-core fibers, multi-component binder fibers, and the like. An exemplary polyethylene fiber is Pulpex®, available from Hercules, Inc. (Wilmington, Del.). Any known bleaching method can be used. Synthetic cellulose fiber types include rayon in all its varieties and other fibers derived from viscose or chemically-modified cellulose.

[0105] Chemically treated natural cellulosic fibers can be used such as mercerized pulps, chemically stiffened or crosslinked fibers, or sulfonated fibers. For good mechanical properties in using papermaking fibers, it can be desirable that the fibers be relatively undamaged and largely unrefined or only lightly refined. While recycled fibers can be used, virgin fibers are generally useful for their mechanical properties and lack of contaminants. Mercerized fibers, regenerated cellulosic fibers, cellulose produced by microbes, rayon, and other cellulosic material or cellulosic derivatives can be used. Suitable papermaking fibers can also include recycled fibers, virgin fibers, or mixes thereof. In certain embodiments capable of high bulk and good compressive properties, the fibers can have a Canadian Standard Freeness of at least 200, more specifically at least 300, more specifically still at least 400, and most specifically at least 500. Other papermaking fibers that can be used in the present disclosure include paper broke or recycled fibers and high yield fibers. High yield pulp fibers are those papermaking fibers produced by pulping processes providing a yield of about 65% or greater, more specifically about 75% or greater, and still more specifically about 75% to about 95%. Yield is the resulting amount of processed fibers expressed as a percentage of the initial wood mass. Such pulping processes include bleached chemithermomechanical pulp (BCTMP), chemithermomechanical pulp (CTMP), pressure / pressure thermomechanical pulp (PTMP), thermomechanical pulp (TMP), thermomechanical chemical pulp (TMCP), high yield sulfite pulps, and high yield Kraft pulps, all of which leave the resulting fibers with high levels of lignin. High yield fibers are well known for their stiffness in both dry and wet states relative to typical chemically pulped fibers.

[0106] In general, any process capable of forming a paper web can also be utilized in the present disclosure. For example, a papermaking process of the present disclosure can utilize creping, wet creping, double creping, embossing, wet pressing, air pressing, through-air drying, creped through-air drying, uncreped through-air drying, hydroentangling, air laying, as well as other steps known in the art.

[0107] The tissue web may be formed from a fiber furnish containing pulp fibers in an amount of at least about 50% by weight, such as at least about 60% by weight, such as at least about 70% by weight, such as at least about 80% by weight, such as at least about 90% by weight, such as 100% by weight.

[0108] The tissue web can also be formed without a substantial amount of inner fiber-to-fiber bond strength. In this regard, the fiber furnish used to form the base web can be treated with a chemical debonding agent. The debonding agent can be added to the fiber slurry during the pulping process or can be added directly to the headbox. Suitable debonding agents that may be used in the present disclosure include cationic debonding agents such as fatty dialkyl quaternary amine salts, mono fatty alkyl tertiary amine salts, primary amine salts, imidazoline quaternary salts, silicone quaternary salt and unsaturated fatty alkyl amine salts. Other suitable debonding agents are disclosed in U.S. Pat. No. 5,529,665 to Kaun which is incorporated herein by reference. In particular, Kaun discloses the use of cationic silicone compositions as debonding agents.

[0109] In one embodiment, the debonding agent used in the process of the present disclosure is an organic quaternary ammonium chloride and, particularly, a silicone-based amine salt of a quaternary ammonium chloride. For example, the debonding agent can be PROSOFT® TQ1003, marketed by the Hercules Corporation. The debonding agent can be added to the fiber slurry in an amount of from about 1 kg per metric tonne to about 10 kg per metric tonne of fibers present within the slurry. In an alternative embodiment, the debonding agent can be an imidazoline-based agent. The imidazoline-based debonding agent can be obtained, for instance, from the Witco Corporation. The imidazoline-based debonding agent can be added in an amount of between 2.0 to about 15 kg per metric tonne.

[0110] In one embodiment, the debonding agent can be added to the fiber furnish according to a process as disclosed in PCT Application having an International Publication No. WO 99 / 34057 filed on Dec. 17, 1998 or in PCT Published Application having an International Publication No. WO 00 / 66835 filed on Apr. 28, 2000, which are both incorporated herein by reference. In the above publications, a process is disclosed in which a chemical additive, such as a debonding agent, is adsorbed onto cellulosic papermaking fibers at high levels. The process includes the steps of treating a fiber slurry with an excess of the chemical additive, allowing sufficient residence time for adsorption to occur, filtering the slurry to remove unadsorbed chemical additives, and redispersing the filtered pulp with fresh water prior to forming a nonwoven web.

[0111] Optional chemical additives may also be added to the aqueous papermaking furnish or to the formed embryonic web to impart additional benefits to the product and process and are not antagonistic to the intended benefits of the invention. The following materials are included as examples of additional chemicals that may be applied to the web along with the additive composition of the present invention. The chemicals are included as examples and are not intended to limit the scope of the invention. Such chemicals may be added at any point in the papermaking process, including being added simultaneously with the additive composition in the pulp making process, wherein said additive or additives are blended directly with the additive composition.

[0112] Additional types of chemicals that may be added to the paper web include, but is not limited to, absorbency aids usually in the form of cationic, anionic, or non-ionic surfactants, humectants and plasticizers such as low molecular weight polyethylene glycols and polyhydroxy compounds such as glycerin and propylene glycol. Materials that supply skin health benefits such as mineral oil, aloe extract, vitamin e, silicone, lotions in general and the like may also be incorporated into the finished products.

[0113] In general, the products of the present invention can be used in conjunction with any known materials and chemicals that are not antagonistic to its intended use. Examples of such materials include but are not limited to odor control agents, such as odor absorbents, activated carbon fibers and particles, baby powder, baking soda, chelating agents, zeolites, perfumes or other odor-masking agents, cyclodextrin compounds, oxidizers, and the like. Superabsorbent particles, synthetic fibers, or films may also be employed. Additional options include cationic dyes, optical brighteners, humectants, emollients, and the like. Tissue webs that may be treated in accordance with the present disclosure may include a single homogenous layer of fibers or may include a stratified or layered construction. For instance, the tissue web ply may include two or three layers of fibers.

[0114] Tissue webs that can be embossed in accordance with the present disclosure can be formed using any suitable process. The tissue webs can comprise wetlaid or foam-formed tissue webs. The tissue webs can be formed using creped wet pressed, modified wet pressed, creped through-air dried, or uncreped through-air dried. In one embodiment, an embryonic tissue web is transferred to a Yankee dryer, which completes the drying process, and then is creped from the surface of the dryer using a doctor blade or other suitable device.

[0115] In other instances, the tissue plies may be manufactured by a through-air dried process known in the art. In such processes the embryonic web is noncompressively dried. For example, textured tissue plies may be formed by either creped or uncreped through-air dried processes. Particularly preferred are uncreped through-air dried webs, such as those described in U.S. Pat. No. 5,779,860, the contents of which are incorporated herein in a manner consistent with the present disclosure.

[0116] In still other instances the tissue plies may be manufactured by a process including the step of using pressure, vacuum, or air flow through the wet web (or a combination of these) to conform the wet web into a shaped fabric and subsequently drying the shaped sheet using a Yankee dryer, or series of steam heated dryers, or some other means, including but not limited to tissue made using the ATMOS process developed by Voith or the NTT process developed by Metso; or fabric creped tissue, made using a process including the step of transferring the wet web from a carrying surface (belt, fabric, felt, or roll) moving at one speed to a fabric moving at a slower speed (at least 5 percent slower) and subsequently drying the sheet. Those skilled in the art will recognize that these processes are not mutually exclusive, e.g., an uncreped TAD process may include a fabric crepe step in the process.

[0117] The tissue product may be constructed from two or more plies that are manufactured using the same or different tissue making techniques. In a particularly preferred embodiment, the multi-ply tissue product comprises two or three plies wherein at least one of the plies is a through-air dried ply.

[0118] The basis weight of tissue webs made in accordance with the present disclosure can vary depending upon the final product. For example, the process may be used to produce bath tissues, facial tissues, paper towels, industrial wipers, and the like. In general, the basis weight of the tissue products may vary from about 10 gsm to about 110 gsm, such as from about 20 gsm to about 90 gsm. For bath tissue and facial tissues, for instance, the basis weight may range from about 10 gsm to about 40 gsm. For paper towels, on the other hand, the basis weight may range from about 25 gsm to about 80 gsm. In multiple ply products, the basis weight of each tissue web present in the product can also vary. In general, the total basis weight of a multiple ply product will generally be the same as indicated above, such as from about 20 gsm to about 110 gsm. Thus, the basis weight of each ply can be from about 10 gsm to about 60 gsm, such as from about 20 gsm to about 40 gsm.

[0119] All different types of products can be made in accordance with the present disclosure. For instance, in one embodiment, the tissue product 10 of the present disclosure can be used to produce a spirally wound roll 200 as shown in FIG. 10. The spirally wound roll 200, for instance, can comprise a bath tissue. As shown, the tissue product 10 includes an embossing pattern 14. The spirally wound roll of the tissue product 10 can be periodically perforated for allowing a user to tear off individual sheets.

[0120] In an alternative embodiment, the tissue product 10 can be formed into a spirally wound roll that comprises a paper towel or industrial wiper.

[0121] In still another embodiment, the tissue product 10 of the present disclosure can be cut into individual sheets and formed into a stack 300 as shown in FIG. 11 . The stack of individual sheets 300 can be interfolded if desired. In one embodiment, the stack of individual sheets 300 can comprise a facial tissue product.

[0122] These and other modifications and variations to the present invention may be practiced by those of ordinary skill in the art, without departing from the spirit and scope of the present invention, which is more particularly set forth in the appended claims. In addition, it should be understood that aspects of the various embodiments may be interchanged both in whole or in part. Furthermore, those of ordinary skill in the art will appreciate that the foregoing description is by way of example only and is not intended to limit the invention so further described in such appended claims.

Claims

What Is Claimed:1 . An embossing roll comprising: a plurality of embossing protuberances that extend from a surface of the embossing roll, each embossing protuberance including a base portion adjacent the surface of the embossing roll and a raised distal portion, each base portion and distal portion having a cross-sectional shape defining a first axis of symmetry and a second axis of symmetry, wherein the first axis of symmetry and the second axis of symmetry intersect one another to form a center point, and wherein the center point of each base portion cross-sectional shape and each corresponding center point of the distal portion cross-sectional shape are not aligned with respect to a vertical axis that is perpendicular to the surface of the embossing roll and intersects the center point of the base portion.

2. An embossing roll as defined in claim 1 , wherein the first axis of symmetry and the second axis of symmetry for each base portion and distal portion are perpendicular to each other.

3. An embossing roll as defined in any of the preceding claims, wherein the distal portion of each embossing protuberance has a circular shape.

4. An embossing roll as defined in any of the preceding claims, wherein the embossing protuberances have an oblique shape.

5. An embossing roll as defined in any of the preceding claims, wherein, based on a direction of rotation of the embossing roll, the embossing protuberances have a leading vertical edge and a trailing vertical edge, the leading vertical edge having an angle in relation to the surface of the embossing roll and the trailing vertical edge having an angle in relation to the surface of the embossing roll, and wherein the angle of the leading vertical edge is smaller than the angle of the trailing vertical edge.

6. An embossing roll as defined in claim 5, wherein the angle of the leading vertical edge is from about 28° to about 68°, such as from about 30° to about 65°, such as from about 45° to about 60°.

7. An embossing roll as defined in any of claims 1 through 3, wherein, based on a direction of rotation of the embossing roll, the embossing protuberances have a leading vertical edge and a trailing vertical edge, the leading vertical edge having an angle in relation to the surface of the embossing roll and the trailing vertical edge having an angle in relation to the surface of the embossing roll, and wherein the angle of the leading vertical edge is greater than the angle of the trailing vertical edge.

8. An embossing roll as defined in claim 7, wherein the angle of the leading vertical edge is from about 46° to about 90°, such as from about 50° to about 80°, such as from about 60° to about9. An embossing roll as defined in any of the preceding claims, wherein the embossing protuberances have a height of from about 0.5 mm to about 2 mm, such as from about 0.8 mm to about 1 .8 mm, such as from about 0.9 mm to about 1 .5 mm.

10. An embossing roll as defined in any of the preceding claims, wherein the cross- sectional shape of the distal portion is circular and has a diameter of from about 0.2 mm to about 1 mm, such as from about 0.3 mm to about 0.9 mm, such as from about 0.4 mm to about 0.8 mm.

11. An embossing roll as defined in any of the preceding claims, wherein the distance between the vertical axis that intersects the center point of the distal portion and the vertical axis that intersects the center point of the base portion is from about 0 05 mm to about 0.8 mm, such as from about 0.1 mm to about 0.5 mm, such as from about 0.2 mm to about 0.5 mm, such as from about 0.25 mm to about 0.5 mm.

12. An embossing roll as defined in any of the preceding claims, wherein the embossing roll is in operative association with a heating device for heating the surface of the embossing roll.

13. An embossing roll as defined in any of the preceding claims, wherein the surface of the embossing roll includes a pattern of embossing protuberances.

14. An embossing roll as defined in claim 13, wherein the surface of the embossing roll includes from about 5 embossing protuberances to about 80,000 embossing protuberances on average per 100 cm2of surface area, such as from about 100 embossing protuberances to about 20,000 embossing protuberances on average per 100 cm2of surface area, such as from about 300 embossing protuberances to about 10,000 embossing protuberances on average per 100 cm2of surface area.

15. An embossing roll as defined in claim 13 or 14, wherein the embossing protuberances form spaced apart rows of line structures.

16. An embossing roll as defined in claim 15, wherein the line structures are curvilinear.

17. An embossing roll as defined in claim 15 or 16, wherein the line structures have a wave-like pattern.

18. A method of embossing a tissue product comprising: feeding a tissue ply through a nip formed between the embossing roll as defined in any of claims 1-17 and a counter roll in order to emboss the tissue ply according to a pattern of embossing protuberances located on the surface of the embossing roll.

19. A process as defined in claim 18, wherein the process produces a single ply tissue product.

20. A process as defined in claim 18, wherein the embossed tissue ply is attached to a second tissue ply for producing a multi-ply tissue product.

21. A process as defined in claim 18, 19, or 20, wherein the embossed tissue ply has a sheet bulk of from about 8 cc / g to about 20 cc / g.

22. A process as defined in any of claims 18-21 , wherein the embossed tissue ply increases in caliper by at least about 10%, such as by at least about 15%, such as by at least about 20%, such as by at least about 25%, such as by at least about 30%, such as by at least about 35%, such as by at least about 40%, such as by at least about 45%, such as by at least about 50%.

23. A process as defined in any of claims 18-22, wherein the tissue ply has a basis weight of from about 14 gsm to about 60 gsm, such as from about 14 gsm to about 30 gsm.

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