Patent Application
20210062432
Products made from paper webs such as bath tissues, facial tissues, paper towels, industrial wipers, food service wipers, napkins, medical pads and other similar products are designed to include several important properties. For example, for most applications, the product should be highly absorbent. In addition, products often should include surface texture in order to provide, for example, a good wiping surface in the case of wiping products or a soft surface texture in products which may be used while in contact with skin. Moreover, absorbent paper products which are multi-ply laminated products should avoid delamination under conditions of use.
Methods for increasing texture at the surface of a paper product are well known in the art. One well-known method is embossing, wherein the fibers in the web are mechanically deformed under high mechanical pressure to impart kinks and microcompressions in the fibers that remain substantially permanent while the web is dry. When wetted, however, the fibers may swell and straighten as the local stresses associated with the kinks or microcompressions in the fiber relax. Thus, embossed tissue when wetted tends to lose much of the added surface texture imparted by embossing and tends to collapse back to a relatively flat state. Similar considerations apply to the fine texture imparted to tissue by creping or microstraining, for such texture is generally due to local kinks and microcompressions in the fibers that may be relaxed when the tissue is wetted, causing the tissue to collapse toward a flatter state than it was in while dry.
Thus, there is a need for a method of converting a dry tissue web or other porous web into a structure having enhanced texture and physical properties. Moreover, there is a need for a highly textured paper product which may maintain a highly textured surface even after becoming wet.
It has now been discovered that tissue products having a highly textured surface may be produced by providing one of the plies forming a multi-ply tissue product with a plurality of macrofolds. The ply comprising the macrofolds may be attached to a conventional, generally planar, tissue ply to provide the dual sided multi-ply tissue product. In certain preferred embodiments the multi-ply product may comprise a first ply, which forms the upper most surface of the product, attached to a substantially planar second ply at longitudinally spaced apart points that define macrofolds therebetween. The length of tissue between the points of attachment may form a wave-like structure having an amplitude and wavelength and having a transversely orientated void that extends from a first edge to a second edge of the tissue. The combination of these elements provides a tissue product that is both aesthetically pleasing and particularly well suited to cleaning due to the large amount of surface area created by the macrofolds.
Accordingly, in one embodiment the present invention provides a tissue product having a machine direction (MD) and a cross-machine direction (CD), a first surface and an opposed bottom surface, the product comprising: a multi-ply tissue web having a first and a second ply, a plurality of spaced apart and repeating lines of perforation disposed on the web, the perforations spaced apart from one another in the MD and defining a plurality of sheets therebetween, the sheets having a sheet length (L); wherein the MD length of the first ply is substantially equal to the sheet length (L) and the MD length of the second ply is at least about 200 percent of the sheet length (L).
In another embodiment the present invention provides a multi-ply tissue product having a machine direction (MD) and a cross-machine direction (CD), a first surface and an opposed bottom surface, a first edge and an opposite second edge, the product comprising: a first ply comprising a plurality of wave-shaped macrofolds extending in the CD from the first edge to the second edge, each macrofold extending in the MD between first and second attachment points and having a MD segment length; and a substantially planar second ply.
In yet another embodiment the present invention provides a multi-ply tissue product having a machine direction (MD) and a cross-machine direction (CD), a first surface and an opposed bottom surface, the product comprising: a first ply comprising a plurality of CD orientated macrofolds, each macrofold having a valley, a peak and a substantially similar uniform wavelength and amplitude, and a substantially planar second ply, wherein the first and second plies are attached to one another by an adhesive disposed between a macrofold valley and the second ply.
In still other embodiments the present invention provides a method of manufacturing a multi-ply tissue product having a machine direction (MD) and a cross-machine direction (CD), a first outer surface, a second outer surface and a plurality of macrofolds disposed on at least one of its outer surfaces comprising the steps of: (a) conveying a first tissue ply through a first nip created by opposed first and second engraved rolls to form a tissue ply having a plurality of macrofolds; (b) applying an adhesive to the macrofolds while supported by the second engraved roll; (c) conveying a second tissue ply through a second nip created by an engraved embossing roll and a substantially smooth resilient roll in opposition to one another to form an embossed tissue ply; (d) conveying the macrofolded tissue ply and embossed tissue plies through a third nip created by the second engraved roll and a marrying roll in opposition to one another; (e) attaching the macrofolded tissue ply and embossed tissue plies to one another by contacting the adhesively treated macrofolds and the embossed tissue ply to one another in the third nip.
As used herein the term “tissue ply” refers to a structure comprising a plurality of fibers 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 tissue ply is a wet-laid sheet material comprising pulp fibers having a basis weight from about 10 to about 45 grams per square meter (gsm), such as from about 13 to about 42 gsm and a sheet bulk greater than about 5 cc/g, such as from about 5 to about 12 cc/g.
As used herein, the term “tissue product” refers to products made from one or more tissue plies and includes, for example, rolled bath tissue, sheets of facial tissue, paper towels, industrial wipers, foodservice wipers, napkins, medical pads, and other similar products. In certain preferred embodiments tissue products of the present invention comprise two or more plies, such as two, three or four plies. Each of the plies of a multi-ply tissue product may be substantially identical, or they may be different, such as having been made by a different tissue manufacturing process or possess at least one physical characteristic such as, for example, tensile strength, stretch, basis weight, or sheet bulk, that differs.
As used herein, 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.
As used herein, the term “machine direction” of a web, ply, or product is the direction within the plane of web, ply, or product parallel to the principal direction of travel of the structure during manufacture. The cross-machine direction is generally orthogonal to the machine direction and also lies within the plane of structure. The Z-direction is orthogonal to both the machine direction and cross-machine direction and generally normal to the plane of structure. The machine direction, cross machine direction, and Z-direction form a Cartesian coordinate system.
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 using TAPPI test method T-220.
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 an EMVECO 200-A Microgage automated micrometer (EMVECO, Inc., Newberg, Oreg.). 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).
As used herein, the term “sheet bulk” refers to the quotient of the caliper (pm) divided by the bone-dry basis weight (gsm). The resulting sheet bulk is expressed in cubic centimeters per gram (cc/g).
As used herein, the terms “geometric mean tensile” (GMT) refers to the square root of the product of the machine direction tensile strength and the cross-machine direction tensile strength of the web.
As used herein the term “line of perforations” generally refers to a line of weakness, such as a plurality of perforations, extending in the transverse cross-machine directional of the web from a first edge to a second edge and providing a means of separating adjacent sheets from one another. The line of perforations may be linear or non-linear.
As used herein the term “sheet” generally refers to a portion of tissue in a rolled tissue product bounded by transverse lines of perforation as is commonly understood in the tissue industry.
As used herein the term “sheet length” generally refers to the distance between a pair of spaced apart transverse lines of perforations defining a sheet. The minimum and maximum sheet lengths are generally determined by the nature of the sheet material product and the needs and preferences of the user. In certain instances, the tissue product may comprise a rolled bath tissue product having a sheet length of about 10 cm or greater, such as from about 10 to about 15 cm.
As used herein the term “macrofold” generally refers to a non-planar portion of a tissue ply having a machine direction ply length that exceeds the machine direction length. In those embodiments where the multi-ply tissue product comprises a ply having a plurality of macrofolds disposed thereon, the macrofolds are generally the portion of the ply extending between two points of attachment. For example, with reference to
As used herein the term “macrofold segment length” refers to the machine direction (MD) length of the tissue ply forming a macrofold between first and second points of attachment. For example, with reference to
The present invention provides multi-ply tissue products having distinctly different first and second outer surfaces or sides. The two-sidedness is generally provided by forming one of the surfaces from a tissue ply, such as a first upper tissue ply, having a plurality of macrofolds and the other side from a substantially planar tissue ply. For example, the first ply may be attached to the second ply at longitudinally spaced apart points that define a macrofold therebetween. The length of tissue between the points of attachment may form a wave-like structure having an amplitude and wavelength and having a transversely orientated void that extends from a first edge to a second edge of the tissue. The combination of these elements provides a tissue product that is both aesthetically pleasing and particularly well suited to cleaning due to the large amount of surface area created by the macrofolds.
The multi-ply embossed tissue products of the present invention generally comprise two, three or four tissue plies made by well-known wet-laid papermaking processes such as, for example, creped wet pressed, modified wet pressed, creped through-air dried (CTAD) or uncreped through-air dried (UCTAD). For example, creped tissue webs may be formed using either a wet pressed or modified wet pressed process such as those disclosed in U.S. Pat. Nos. 3,953,638, 5,324,575 and 6,080,279, the disclosures of which are incorporated herein in a manner consistent with the instant application. In these processes the embryonic tissue web is transferred to a Yankee dryer, which completes the drying process, and then creped from the Yankee surface using a doctor blade or other suitable device.
In other instances, the tissue plies may be formed 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.
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.
The instant multi-ply 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 three plies where each of the plies comprises a wet-pressed tissue ply, where each ply has a basis weight greater than about 10 gsm, such as from about 10 to about 45 gsm, such as from about 12 to about 42 gsm.
Regardless of the tissue making process used to produce the individual plies, the resulting multi-ply tissue product has a first surface having a plurality of macrofolds. As shown in
The first ply 110 is substantially planar and in certain instances may comprise a plurality of embossments. The second ply 120 comprises a plurality of macrofolds 121. Each macrofold 121 generally extends between first and second points of attachment 131, 133, which in certain preferred embodiments are formed by an adhesive 130 disposed between the first and second plies 110, 120. In a particularly preferred embodiment, individual plies of a multi-ply product may be attached to one another by an adhesive 130 disposed between a first ply 110 and the macrofold valley 124 of a second ply 120. In other embodiments, macrofold ends may be joined to the bottom ply using other well-known ply attachment means such as mechanical crimping or embossing.
In a particularly preferred embodiment, each of the plurality of macrofolds 121 are similarly sized. For example, the points of attachment 131, 133 defining each of the macrofolds 121 may be spaced apart an equal distance, such as at least about 8.5 mm, such as from about 5.0 to about 16 mm, such as from about 7.0 to about 10 mm. Further, the macrofold segment length 135 (shaded portion between points of attachment 131, 133), may range from about 8.0 to about 24 mm, such as from about 10 to about 22 mm, such as from about 12 to about 20 mm. In certain preferred embodiments each of the macrofolds has a ratio of macrofold segment length to attachment length greater than 2.0 mm, and more preferably greater than about 3.0 mm, such as from about 2.5 to about 4.5 mm, such as from about 3.0 to about 4.0 mm.
In a particularly preferred embodiment, such as illustrated in
As further illustrated in
With continued reference to
In certain embodiments, one or more of the outer most plies of the tissue product may comprise a plurality of embossments. In one preferred embodiment, the first ply, which generally forms the bottom surface of the tissue product, may have a total embossed area from about 5 to about 40 percent, more preferably ranging from about 8 to about 35 percent, even more preferably ranging from about 20 to about 25 percent. In a preferred embodiment, only embossed elements that are completely disposed upon the tissue sheet surface are utilized for the calculation of total embossment footprint area. However, one of skill in the art would be able to utilize such fractional portions of embossed elements in accordance with the present invention to determine the appropriate relationship of total embossment footprint area to total surface area of a tissue sheet.
Without desiring to be bound by theory, an optimized percentage of the tissue surface area covered by the embossing pattern, such as from about 5 about 40 percent, and more preferably from about 8 to about 25 percent, and the pattern consisting essentially of organic shaped embossed elements formed from dot emboss elements communicates to the consumer that the product is soft and cushiony. Additionally, at the foregoing area coverage and shapes the emboss pattern has an aesthetic quality that does not appear overly complicated but simplistic and natural.
The tissue products of the present invention, in particular embodiments, may be manufactured by a process whereby the top ply is deformed in such a way that, when combined with a bottom ply, a plurality of macrofolds are formed. One suitable process is illustrated in
The first and second engraved rolls 211, 212 are generally hard and non-deformable rolls, such as a steel roll, and comprise first and second protuberances 214, 216. The protuberances extend radially from a first peripheral surface of the rolls and are arranged to form a meshing engagement when the rolls are brought together to form a nip. The protuberances have a radial height generally measured from the first peripheral surface of the roll, which is understood to be the circumferential surface of the roll having the least radial height when measured from the axis of the roll, or some other common reference point. In certain embodiments the radial height of the protuberances 214 disposed on the first roll 211 may have a height of about 3.0 mm or greater, such as from about 3.0 to about 20 mm and more preferably from about 6.0 to about 15 mm. The radial height of the protuberances 216 disposed on the second roll 212 may have a height of about 3.0 mm or greater, such as from about 6.0 to about 20 mm and more preferably from about 8.0 to about 14 mm.
The protuberances 214, 216 of the first and second engraved rolls 211, 212 extend generally transversely in the cross-machine direction along the entire width of the rolls. The protuberances 214, 216 are spaced apart from one another and have land areas disposed therebetween. Preferably the land areas, like the protuberances are continuous within a given dimension of the engraved roll.
The spacing and arrangement of the protuberances on each of the first and second rolls may vary depending on the desired tissue product properties and appearance. The shape of the element may also be varied to provide the desired tissue product properties and appearance. For example, in one embodiment, such as that illustrated in
In those embodiments where the protuberances 214 of the first engraved roll 211 are provided with a second set of protuberances 261, which may have any number of different shapes and may be provided to emboss the first tissue ply along a portion of the ply between the spaced apart macrofolds. In a particularly preferred embodiment, such as illustrated in
The first and second engraved rolls 211, 212 are urged together to form a first nip 210 through which the first tissue ply 201 passes to form a plurality of macrofolds 230 thereon. Generally, a force or pressure is applied to one or both of the rolls 211, 212 such that the rolls 211, 212 are urged against one another causing the first tissue ply 201 to conform to protuberances 214, 216 as it passes through the nip 210. As shown in detail in
As the macrofold is generally formed by the first ply conforming to the protuberances disposed on the first and second rolls, the shape and size of the macrofold may be controlled to a certain degree by the shape of the protuberances. For example, in certain preferred embodiments, all the protuberances 214 disposed on the first roll 211 may be similarly shaped and sized and all of the protuberances 216 on the second roll 212 may be similarly shaped and sized. In this manner, when the first ply 201 passes through the first nip 210 the resulting macrofolds 230 may all be similarly shaped and sized.
To form a two-ply tissue product, a second parent roll 202 is unwound and the second tissue ply 204 is conveyed around an idler roller 220 and then passed into a second nip 215 formed between an impression roll 217 and an engraved embossing roll 213. The impression roll generally has a smooth outer surface, which may be deformable. In certain instances, the impression roll has an outer covering comprising a natural or synthetic rubber and may have a hardness greater than about 40 Shore (A), such as from about 40 to about 100 Shore (A). The engraved embossing roll 213 generally comprises a plurality of protuberances 222 extending from its peripheral surface 221. In one embodiment the protuberances 222 may comprise a plurality of discrete dot elements and form an embossing pattern. In certain embodiments the protuberances disposed on the engraved embossing roll may have a height of at least about 0.4 mm, such as from about 0.4 to about 2.0 mm.
As the second ply 204 passes through the embossing nip 215 it is imparted with a plurality of embossments 231, which may be arranged to form an embossing pattern. The embossed second ply 224 is then conveyed and brought into facing relation with the first ply 205, which has been provided with a plurality of macrofolds 230, using a marrying roll 240. While in certain instances the engraved embossing roll 213 and impression roll 217 may be arranged relatively close to the first pair of rolls 211, 212 and the marrying roll 240, this is not necessary because the present method does not rely upon registration of the macrofolds and the embossing pattern.
After the embossed second ply 224 leaves the embossing nip 215 it is brought into facing relationship with the macrofolded first ply 205. The two plies 205, 224 are conveyed through a third nip 242 formed between the second roll 212 and a marrying roll 240, which may be a steel roll having a substantially smooth outer surface. The embossed second ply 224 and the macrofolded first ply 205 are joined together as they pass through the third nip 242 to form a multi-ply tissue product 280.
In certain embodiments, after exiting the first nip 210 the macrofolded first ply 205 encounters a gluing unit 250, which comprises an adhesive 251 disposed in a reservoir and an applicator roll 252. Adhesive 251 is transferred to the applicator roll 252 and applied to the macrofold distal ends 232. The macrofolded first ply 205 with the applied adhesive 251 then advances further to the third nip 242 between the second roll 212 and the marrying roll 240. At this point, the embossed second ply 224 is attached to the macrofolded first ply 205 and then conveyed through the third nip 242 to form an adhesively laminated two-ply tissue product 280 which may be subsequently wound into a roll (not shown). The two-ply tissue product 280 comprises a macrofolded first ply 205 and a second embossed ply 224 with the macrofolded first ply 205 forming the upper most surface of the tissue product 280 and the second embossed ply 224 forming the bottom most surface.
In certain embodiments, to improve processability and one or more physical properties, one or more of the fibrous plies may be subjected to preconditioning to impart moisture and/or heat to the tissue plies prior to entering an embossing nip. For example, preconditioning mechanisms may be positioned upstream of the nip located between the engraved roll and the impression role to introduce moisture and/or heat to the first tissue ply prior to embossing. Methods and arrangements for applying moisture and heat (e.g., steam) to tissue webs are known to skilled artisans and can be employed and fall within the scope of the present invention. By way of example, steam can be applied to either or both sides of a web prior to embossing.
The multi-ply tissue products of the present invention may have a basis weight from about 20 to about 90 gsm, such as from about 30 to about 70 gsm, such as from about 42 to about 60 gsm. In certain instances, the multi-ply embossed tissue products may comprise two, three or four tissue plies where the basis weight of each individual tissue ply is less than about 25 gsm, such as from about 10 to about 20 gsm, such as from about 10 to about 15 gsm. In certain instances, the present invention provides a multi-ply tissue product comprising a first macrofolded tissue ply having a basis weight from about 10 to about 42 gsm and a second surface embossed tissue ply having a basis weight from about 10 to about 42 gsm.
In other embodiments, the multi-ply tissue products of the present invention may have a geometric mean tensile (GMT) strength from about 800 to about 1,800 g/3″, such as from about 800 to about 1,600 g/3″, such as from about 800 to about 1,500 g/3″. In a particularly preferred embodiment, the invention provides a tissue product comprising a first macrofolded ply and a second embossed ply, the product having a GMT from about 800 to about 1,800 g/3″, such as from about 800 to about 1,600 g/3″, such as from about 800 to about 1,500 g/3″, and a basis weight from about 30 to about 65 gsm, such as from about 42 to about 60 gsm.
With reference now to
In addition to macrofolds 121, the second, upper, ply 120 further comprises a plurality of embossments 132, which in the illustrated embodiment are discrete dot embossments. The embossments 132, are disposed in an embossing pattern between macrofolds 121, which are spaced apart from one another in the machine-direction. The embossments 132 extend transversely across the width of the multi-ply tissue web 100 in the cross-machine direction.
Turning now to
Each sheet 142 comprises a first and second ply 110, 120. The second, upper, ply 120 comprises a plurality of macrofolds 121 that extend transversely in the CD across the width of the sheet 142 in a substantially continuous fashion. As described previously, the macrofolds 121 are formed by a portion of the upper ply 120 and extend between first and second points of attachment 131, 133, which in certain embodiments may be an adhesive disposed between the first and second plies 110, 120. The formation of macrofolds 121 in the second ply 120, causes the length of tissue web forming the first ply 110 to have a MD length that is greater than the sheet length (L).
In certain preferred embodiments the first, bottom, ply is substantially planar and has a MD length equal to the sheet length (L). The second, upper, ply comprises a plurality of macrofolds, which result in the ply having a MD length that is at least about 150 percent of the sheet length (L). In other embodiments, the MD length of the second ply is from about 120 to about 600 percent of the sheet length (L), such as from about 150 to about 400 percent of the sheet length (L), such as from about 180 to about 300 percent of the sheet length (L).
The MD sheet length of the first and second plies may be measured by separating a sheet from an adjacent sheet along the line of perforations. The separated sheet may then be further separated into individual plies by gently lifting on the upper most ply, generally the ply comprising macros-folds, to separate the plies from one another, taking care not to tear the plies. Once separated into individual plies, the plies are flattened by applying a slight tension to the ends of the plies, which may be accomplished by simply using one's hands to extend the plies, and the MD length is measured using conventional means.
With reference now to
As further illustrated in
In those embodiments, such as illustrated in
In-use, such as illustrated in
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/US19/48687 | 8/29/2019 | WO | 00 |
