CA2236829A1 - Sheet orientation for soft-nip calendering and embossing of creped throughdried tissue products - Google Patents
Sheet orientation for soft-nip calendering and embossing of creped throughdried tissue products Download PDFInfo
- Publication number
- CA2236829A1 CA2236829A1 CA 2236829 CA2236829A CA2236829A1 CA 2236829 A1 CA2236829 A1 CA 2236829A1 CA 2236829 CA2236829 CA 2236829 CA 2236829 A CA2236829 A CA 2236829A CA 2236829 A1 CA2236829 A1 CA 2236829A1
- Authority
- CA
- Canada
- Prior art keywords
- web
- roll
- calendering
- fabric
- resilient
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Classifications
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21F—PAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
- D21F11/00—Processes for making continuous lengths of paper, or of cardboard, or of wet web for fibre board production, on paper-making machines
- D21F11/14—Making cellulose wadding, filter or blotting paper
- D21F11/145—Making cellulose wadding, filter or blotting paper including a through-drying process
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21F—PAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
- D21F11/00—Processes for making continuous lengths of paper, or of cardboard, or of wet web for fibre board production, on paper-making machines
- D21F11/14—Making cellulose wadding, filter or blotting paper
Landscapes
- Paper (AREA)
Abstract
The texture of creped, throughdried tissue products is improved by processing the tissue web through a soft-nip calendering unit with the fabric side of the web oriented toward a resilient roll and the air side of the web oriented toward a smooth steel roll. Specifically, a wet web having a fabric side in contact with a throughdrying fabric and an opposite air side facing away from the throughdrying fabric is throughdried and creped. The web is then calendered in a nip including a resilient calendering roll having a Shore A surface hardness of about 75 to about 100 Durometer. The creped web isoriented such that the fabric side is disposed toward the resilient calendering roll, and may also be embossed with the fabric side disposed toward the pattern roll.
Description
SHEET ORIENTATION FOR SOFT-NIP CALENDERING
AND EMBOSSING OF CREPED THROUGHDRIED TISSUE PRODUCTS
Background of the Invention The present invention relates to tissue products. More particularly, the presentinvention relates to the manufacture of creped throughdried tissue products.
A wide variety of product characteristics must be given attention in order to provide a tissue product with the appropriate blend of attributes suitable for the product's intended purposes. Contributing to this variety is the vast array of different product forms, such as facial tissue, bath tissue, napkins, and towels. Regardless of product form, however, improved softness of the product has long been one major objective, especially for premium products. In general, the major components of softness include stiffness and bulk, with lower stiffness and higher bulk generally improving perceived softness.
A throughdrying process can be used to improve the bulk of tissue products.
Throughdrying is a relatively noncompressive method for removing water from a web.
Specifically, a wet laid web is transferred from a forming fabric to a coarse, highly permeable throughdrying fabric and retained on the throughdrying fabric until it is dried by hot air passing through the web.
Throughdried sheets can be quite harsh and rough to the touch, however, due to their inherently high stiffness and strength and also due to the coarseness of the throughdrying fabric. For this reason, creping has been used to improve the softness of throughdried tissue sheets. Creping removes some of the stiffness of the uncreped sheet, albeit at the expense of the sheet strength.
Despite the improvements in softness that can be gained from creping, however, additional improvements in softness would be beneficial to consumers. Therefore, what is lacking and needed in the art is a process for further improving the softness of creped throughdried tissue products.
Summary of the Invention It has now been discovered that the texture of creped, throughdried tissue products can be improved by processing the tissue web through a soft-nip calendering unit with the fabric side of the web oriented toward a resilient roll and the air side of the web oriented toward a smooth roll. More specifically, in one embodiment the invention concerns a method for making a throughdried tissue sheet comprising the steps ofdepositing an aqueous suspension of papermaking fibers onto an endless forming fabric to form a wet web, and then transferring the wet web to a throughdrying fabric. The wet web is described herein as having a fabric side, which is the surface that is in contact with the throughdrying fabric, and an opposite air side, which is the surface that is facing away from the throughdrying fabric. The wet web is then carried over a throughdryer to dry the web, transferred to a Yankee dryer, and creped from the Yankee dryer. The creped web is then calendered in a calendering unit comprising a smooth calendering roll and a resilient calendering roll having a Shore A surface hardness of about 75 to about 100 Durometer. During calendering, the creped web is oriented such that the fabric side is disposed toward the resilient calendering roll.
In another embodiment, the method of making a throughdried tissue sheet also comprises the step of embossing the creped web in an embossing unit comprising apattern roll and a backing roll. In the embossing unit, the creped web is oriented such that the fabric side of the web is disposed toward the pattern roll.
The improved softness is particularly pertinent to creped throughdried tissue products, which typically have larger creping features than a comparable wet pressed sheet. Moreover, the oriented soft-nip embossing is advantageously used in conjunction with oriented embossing of the tissue web. In particular, the resilient backing roll of the embossing unit is against the opposite surface of the tissue sheet as is the resi~ient calendering roll.
Applicants have examined the texture of tissue products to determine the attributes that result in a tissue product being considered soft. One attribute of a surface of a tissue that is indicative of the softness of the tissue is referred to as the Fuzzy attribute of the tissue surface. Contrariwise, attributes of a tissue surface that are counter-indicative of the softness of the tissue are referred to as the Gritty and Grainy attributes of the tissue surface.
The methods disclosed herein have been found to increase the Fuzzy attribute of the fabric side of the tissue product and reduce the Gritty and Grainy textures of the air side of the tissue product. The Fuzzy attribute is increased, particularly on the fabric side, as a result of frictional forces in the calendering nip caused by the speed differential at the contact point between the resilient calendering roll and the steel calendering roll. The creping process causes the air side of the tissue web to have pointed crepe structures such as ripples or ridges which result in Gritty and Grainy textures, and that contact between the steel calendering roll and the air side tends to flatten the pointed crepe structures present on the air side, thereby reducing the Gritty and Grainy textures. In addition, it is hypothesized that the clarity of the embossing pattern is improved because of an increase in opacity caused by calendering the sheet.
The result of the selective orientation and distinctive treatment of the opposite surfaces of the creped throughdried tissue is an embossed tissue web with enhanced softness.
For purposes herein, a "tissue web" or "tissue sheet" is a cellulosic web suitable for making or use as a facial tissue, bath tissue, paper towels, napkins, or the like. It can be layered or unlayered, creped or uncreped, and can consist of a single ply or multiple plies. In addition, the tissue web can contain reinforcing fibers for integrity and strength.
Tissue webs suitable for use in accordance with this invention are characterized by being absorbent, of low density and relatively fragile, particularly in terms of wet strength. Densities are typically in the range of from about 0.1 to about 0.3 grams per cubic centimeter. Absorbency is typically about 5 grams of water per gram of fiber, and generally from about 5 to about 9 grams of water per gram of fiber. Wet tensile strengths are generally about 0 to about 300 grams per inch of width and typically are at the low end of this range, such as from about 0 to about 30 grams per inch. Dry tensile strengths in the machine direction can be from about 100 to about 2000 grams per inch of width, preferably from about 200 to about 350 grams per inch of width. Tensile strengths in the cross-machine direction can be from about 50 to about 1000 grams per inch of width, preferably from about 100 to about 250 grams per inch of width. Dry basis weights are generally in the range of from about 5 to about 60 pounds per 2880 square feet. The-tissue webs referred to above are preferably made from natural cellulosic fiber sources such as hardwoods, softwoods, and nonwoody species, but can also containsignificant amounts of recycled fibers, sized or chemically-modified fibers, or synthetic fibers.
Tissue sheets which particularly benefit from the method of this invention are premium quality throughdried tissue sheets which have a relatively high degree of resiliency and low stiffness. The basis weight of the tissue sheet can be from about 5 to about 70 grams per square meter.
Referring now to the tissue making process of this invention, the forming process and tackle can be conventional as is well known in the papermaking industry. Such formation processes include Fourdrinier, roof formers such as a suction breast roll, gap formers such as twin wire formers and crescent formers, and other suitable formers. A
twin wire former may be preferred for higher speed operation. Forming wires or fabrics can also be conventional, the finer weaves providing greater fiber support and a smoother sheet and the coarser weaves providing greater bulk. Headboxes used to deposit the fibers onto the forming fabric can be layered or nonlayered, although layered headboxes are advantageous because the properties of the tissue can be finely tuned by altering the composition of the various layers. The throughdryers and throughdrying fabrics can also be of a conventional nature.
Brief DescriPtion of the Drawings Figure 1 is a schematic process flow diagram illustrating a method of making a creped throughdried web and winding the web into a parent roll.
Figure 2 is a schematic process flow diagram for a method of converting the tissue web using a calendering unit and an embossing unit.
Figure 3 representatively shows exemplary calendering and embossing units used in the converting process shown in Figure 2.
Figure 4 representatively shows a plan view of a portion of the surface of an exemplary pattern roll used in the embossing unit shown in Figure 3.
Figure 5 representatively shows a graph of data collected as part of a sensory panel evaluation pertaining to Examples 1 - 3 described below.
Detailed DescriPtion of the Drawings A method for carrying out the present invention is show in greater detail in theprocess flow diagram of Figure 1. A headbox 10 deposits an aqueous suspension ofpapermaking fibers onto the surface of a forming fabric 11. The resulting wet web 12 is transferred to an optional fine mesh transfer fabric 13 and thereafter transferred to a coarse mesh throughdryer fabric 14. In the illustrated process, two throughdryers 16 and 17 are used to dry the web 12. The web 12 may be partially dried in the first throughdryer 16 to a consistency of about 45 percent. The partially dried web 12 is then carried over the second throughdryer 17 and further dried to a consistency of about 85 to about 95 percent.
The tissue web 12 has opposite major planar surfaces which are referred to herein as the air side 18 and the fabric side 20. The air side 18 of the tissue web 12 is the surface of the web that faces away from the throughdryer fabric 14 and the surfaces of the throughdryers 16 and 17. Correspondingly, the fabric side 20 is the surface that is directed toward and placed in contact with the throughdryer fabric 14.
Upon exiting the second throughdryer, the web 12 is transferred to a fine mesh fabric 21 and pressed onto the surface of a Yankee dryer 22 for final drying, ifnecessary. The fabric side 20 of the web 12 is disposed against the surface of the Yankee. The web 12 is dislodged from the Yankee dryer 22 with a doctor (creping)blade 23 to produce a creped tissue web 24 that is wound into a parent roll 26.
For simplicity, the various tensioning rolls schematically used to define the several fabric runs are shown but not numbered. It will be appreciated that variations from the apparatus and method illustrated in Figure 1 can be made without departing from the scope of the invention. For example, additional dewatering of the wet web can be carried out, such as by vacuum suction, while the wet web is supported by theforming fabric; only a single throughdryer may be used; or the like.
Figure 2 illustrates an off-line converting operation to calender and emboss thecreped tissue web 24 in accordance with the present invention. The tissue web 24 is unwound from a parent roll 26 and transported in sequence to a calendering unit 30 and an embossing unit 40. The calendered and embossed tissue web 24 may then be wound at a rewinding unit 60. For example, the tissue web 24 may be wound onto tissue roll cores to form logs, which are subsequently cut into appropriate widths and the resulting individual tissue rolls are packaged (not shown).
Exemplary calendering and embossing units 30 and 40 are shown in greater detail in Figure 3. Note that in the winding and unwinding processes of Figures 1 and 2, the orientation of the tissue web 24 in the illustrated embodiment has been reversed so that the fabric side 20 of the tissue web is shown on the top and the air side 18 is shown on the bottom in Figures 2 and 3. Arrows are used to designate the direction of web travel through the calendering and embossing units 30 and 40.
The calendering unit 30 comprises a pair of calendering rolls 32 and 34 that together define therebetween a calendering nip 36. A spreader roll 38 is shown preceding the calendering nip 36, although other details of the calendering unit 30 are not shown for purposes of clarity.
The calendering nip 36 is a "soft-nip" wherein the rolls have different surface hardnesses and at least one of the rolls has a resilient surface. Resilient calendering rolls suitable for the present invention are typically referred to as rubber covered calendering rolls, although the actual material may comprise natural rubber, synthetic rubber, composites, or other compressible surfaces. Suitable resilient calendering rolls may have a Shore A surface hardness from about 75 to about 100 Durometer (approximately 0 to 55 Pusey & Jones), and particularly from about 85 to about 95 Durometer (approximately 10 to 40 Pusey & Jones). For instance, the calendering rolls may comprise a smooth steel roll 34 and a smooth resilient roll 32 formed of a composite polymer with a Shore A surface hardness of about 90 Durometer (approximately 25 - 30 Pusey & Jones). The calendering nip pressure is suitably from about 30 to about 200 pounds per lineal inch, and more particularly from about 75 to about 175 pounds per lineal inch.
Upon exiting the calendering unit 30, the tissue web 24 is transported to an embossing unit 40 comprising a pattern roll 42 and a backing roll 44. The pattern and backing rolls 42 and 44 together define therebetween an embossing nip 46. A spreader roll 48 is shown preceding the embossing nip 46, although other details of the calendering unit 30 are not shown for purposes of clarity.
Embossing is a well-known mechanism to increase sheet caliper, and it also provides an additional benefit by imparting a decorative pattern to the tissue product.
These decorative patterns are commonly formed by "spot embossing", which involves discrete embossing elements that are about 0.5 inch by 0.5 inch to about 1 inch by 1 inch in size, and thus from about 0.25 to about 1 square inch in surface area. These discrete embossing elements are typically spaced about 0.5 inch to about 1 inch apart.
The spot embossing elements are formed on a pattern roll, which is also referred to as an embossing roll, and are pressed into the tissue sheet.
A plan view of a portion of the surface of an exemplary pattern roll 42 is shown in Figure 4. The surface of the pattern roll 42 includes a plurality of discrete male spot embossing elements 50 that are separated by smooth land areas 52. The male spot embossing elements 50 define a decorative pattern, which in the illustrated embodiment is a series of cotton balls. The male spot embossing elements 50 may comprise a plurality of separate embossing element segments 54 which are raised above the surface of the land areas 52. Each cotton ball depicted in Figure 4 is a spot embossing element 50 comprising ten individual embossing element segments 54.
The spaced-apart discrete spot embossing elements or embossments can depict flowers, leaves, birds, animals, and the like. The pattern roll 42 may be formed by engraving or other suitable techniques.
In particular embodiments, the male embossing element segments 54 protrude from the surface of the embossing roll a distance or height which may be greater than about 0.04 inch, such as from about 0.045 inch to about 0.060 inch, for example about 0.045 inch. This relatively large element height enhances the embossing pattern definition. The width of the embossing element at its tip can be from about 0.005 to about 0.50 inch. The sidewall angle of the male embossing element segments measured relative to the plane tangent to the surface of the roll at the base of the embossing element is suitably from about 90 degrees to about 130 degrees.
As disclosed in copending U.S. Patent Application Serial No. unassigned, filed on even date herewith by Z. Salman et al. and titled "Calendered And Embossed Tissue Products," high-bulk tissue products can be embossed with improved pattern clarity by processing the high bulk tissue webs sequentially through separate calendering and embossing units. This multiple step converting process provides a method of optimizing the balance between sheet caliper for winding tension and embossing element height for pattern definition. The result is an embossed, high-bulk tissue product with improved embossing pattern clarity.
As used herein, the term "pattern definition" refers to the extent to which the embossed pattern can be immediately identified by distinct impressions made by the embossing element. The term "pattern clarity" as used herein refers to the clearness of the pattern in the final product.
The backing roll 44 may comprise a smooth rubber covered roll, an engraved roll such as a steel roll matched to the pattern roll, or the like. The bonding nip may be set to a pattern/backing roll loading pressure from about 80 to about 150 pounds per lineal inch, for example an average of about 135 pounds per lineal inch, such that the embossing pattern is imparted to the tissue web 24. The backing roll can be any material that meets the process requirements such as natural rubber, synthetic rubber or other compressible surfaces, and may have a Shore A surface hardness from about 65 to about 85 Durometer, such as about 75 Durometer.
ExamPles The following Examples are provided to give a more detailed understanding of theinvention. The particular amounts, proportions, compositions and parameters are meant to be exemplary, and are not intended to specifically limit the scope of the invention. In order to better compare the effects of the orientation of the fabric and air sides of the throughdried tissue, none of the Example sheets were embossed. The converting lines all ran at 1000 feet per minute.
Example 1. (ComParative) A throughdried and creped tissue sheet was manufactured having a caliper of 0.010 inch and a basis weight of about 15.2 pounds per 2880 square feet. The tissue sheet was slit into narrow rolls for use on converting lines. A narrow roll of the throughdried and creped tissue was unwound and then rewound as a control. Basesheet samples were prepared for sensory evaluation from this converted roll. Thus, the tissue sheet of Example 1 was not calendered.
Example 2. (Comcarative) For Example 2, a narrow roll of throughdried and creped tissue as described in Example 1 was unwound, calendered, and then rewound.
Basesheet samples were prepared for sensory evaluation from this converted roll.The calendering unit comprised a smooth steel calendering roll and a smooth resilient calendering roll. The resilient calendering roll had an exterior covering formed of a composite polymer from Stowe Woodward Company, U.S.A., under the tradename MULTICHEM, with a Shore A hardness of 90 Durometer. The calendering nip was set to 30 pounds per lineal inch.
The tissue sheet was processed through the calendering nip such that the fabric side of the sheet was disposed against the steel calendering roll and the air side was disposed against the resilient calendering roll.
Exam~le 3. For Example 3, a narrow roll of throughdried and creped tissue as described in Example 1 was unwound, calendered, and then rewound. Basesheet samples were prepared for sensory evaluation from this converted roll. The components of the calendering unit and the operating conditions were the same asdescribed in Example 2, although the positions of the steel calendering roll and the resilient calendering roll were transposed.
Thus, in Example 3 the tissue sheet was processed through the calendering nip such that the fabric side of the sheet was disposed against the resilient calendering roll and the air side was disposed against the steel calendering roll.
The bath tissue sheets of Examples 1, 2 and 3 were submitted for sensory panel evaluation. The sensory panel utilized eleven individuals trained to compare tissue products and evaluate tactile properties. The panelists were asked to render numerical values for each Example tissue regarding the following attributes: Fuzzy attribute for both the air side and the fabric side; Gritty attribute for both the air side and the fabric side; Grainy attribute for both the air side and the fabric side; stiffness; and thickness.
For each Example bath tissue, the tissue samples were die cut from the rolls to 8 by 4.5 inches.
The Fuzzy attribute was ranked on a scale from O described as none/bald to 7 described as much/fuzzy. The panelists were asked to consider the amount of fibers, pile, fiber, nap, and fuz on the tissue surface. The panelists were instructed to: place a single tissue sample flat on a smooth tabletop with the side to be tested facing up; and using the pads of the index and middle fingers, move in quarter-sized circular motions very lightly across several areas of the sample.
The Gritty attribute was ranked on a scale from O described as smooth to 7 described as gritty. The panelists were asked to consider the amount of sharp, prickly, abrasive particles or fibers felt on the surface of the sample. The panelists were instructed to: place a single tissue sample on a table with the side to be tested facing up; with forearm/elbow resting on the table and using the full length of the fingers, slowly glide your fingers lightly across the entire surface one inch from the edge moving left to right; use the other hand to rotate the tissue sample and stroke along all four directions;
and evaluate the grittiest direction.
The Grainy attribute was ranked on a scale from O described as smooth to 7 described as grainy. The panelists were asked to consider the pebbly texture of the tissue sample (feeling of grains of sand, rice), and to evaluate by considering the frequency, size, and hardness/firmness/rigidity of grains. It was noted that the panelist's perception can include shape, orientation and size of texture (pattern/embossing), small rounded particles, fibers, etc. The panelists were instructed to: place a single tissue sample on a table with the side to be tested facing up; with forearm/elbow resting on the table and using the pads of the index and middle fingers, slowly and gently move the pads of your fingers across the surface going slightly into the surface of the sample, one inch from the edge moving left to right; use the other hand to rotate the tissue sample and stroke along all four directions; and evaluate the grainiest direction.
Stiffness was ranked on a scale from O described as pliable/flexible to 7 described as stiff/rigid. The panelists were asked to consider the amount of pointed, rippled or cracked edges or peaks felt from the sample while turning in your hand. The panelists were instructed to: place 2 tissue samples flat on a smooth tabletop; the bath tissue samples should overlap one another by 0.5 inch and be flipped so that opposite sides of the tissue samples are represented during testing; with forearm/elbow resting on the table, place your open hand palm down on the samples; position your hand so your fingers are pointing toward the top of the samples approximately 1.5 inch from the edge; draw your fingers toward your palm with little or no downward pressure to gather the tissue samples; gently move the gathered samples around in the palm of your hand approximately 2-3 turns.
Thickness was ranked on a scale from O described as thin to 7 described as thick. The panelists were asked to consider the relative depth of tissue (perceived distance between thumb and one/two fingers). The panelists were instructed to: using a single sample piece, gently hold the tissue with thumb between your index and second fingers; with your other hand gently pull the tissue out of your hold; repeat this procedure several times on the lower edge of the tissue to evaluate the degree of thickness as your fingers come together off the edge of the tissue.
The data collected from the sensory panel analysis is presented in Table 1 belowand is graphically displayed in Figure 4. The attribute values represent averages of all of the panelists.
Table 1 Sensory Panel Profile Attribute ExamDle 1 Example2 Example 3 Fuzy 3.94 4.74 5.49 (air side) Fu~y 5.43 5.75 5.85 (fabric side) Gritty 3.56 2.25 1.98 (air side) Gritty 2.11 1.77 1.98 (fabric side) Grainy 2.55 1.41 1.35 (air side) Grainy 1.95 1.28 1.37 (fabric side) Stiffness 5.84 6.01 5.89 Thickness 4.31 4.26 4.35 Thus, the sensory panel comparisons indicate that soft-nip calendering with the fabric side oriented toward the resilient roll, represented by Example 3, increases the Fuzy attribute of softness more than soft-nip calendering with a transposed orientation of the calendering rolls, represented by Example 2. As noted previously, increasing the Fuzy attribute indicates improved softness. Because the Fuzzy value is greater on both the air side and the fabric side when the fabric side is oriented toward the resilient roll (Example 3), it follows that the overall softness of the tissue is better using this orientation.
The reduction of the Gritty and Grainy values on the air side of the tissue is aresult of flattened crepe folds. Soft-nip calendering with the fabric side oriented toward the resilient roll (Example 3) increases the Fuzzy attribute at a 95 percent confidence level and directionally decreases the Gritty and Grainy attributes, resulting in a less two-sided sheet as compared to both Examples 1 and 2.
It will be appreciated that the foregoing examples, given for purposes of illustration, are not to be construed as limiting the scope of this invention, which is defined by the following claims and all equivalents thereto.
AND EMBOSSING OF CREPED THROUGHDRIED TISSUE PRODUCTS
Background of the Invention The present invention relates to tissue products. More particularly, the presentinvention relates to the manufacture of creped throughdried tissue products.
A wide variety of product characteristics must be given attention in order to provide a tissue product with the appropriate blend of attributes suitable for the product's intended purposes. Contributing to this variety is the vast array of different product forms, such as facial tissue, bath tissue, napkins, and towels. Regardless of product form, however, improved softness of the product has long been one major objective, especially for premium products. In general, the major components of softness include stiffness and bulk, with lower stiffness and higher bulk generally improving perceived softness.
A throughdrying process can be used to improve the bulk of tissue products.
Throughdrying is a relatively noncompressive method for removing water from a web.
Specifically, a wet laid web is transferred from a forming fabric to a coarse, highly permeable throughdrying fabric and retained on the throughdrying fabric until it is dried by hot air passing through the web.
Throughdried sheets can be quite harsh and rough to the touch, however, due to their inherently high stiffness and strength and also due to the coarseness of the throughdrying fabric. For this reason, creping has been used to improve the softness of throughdried tissue sheets. Creping removes some of the stiffness of the uncreped sheet, albeit at the expense of the sheet strength.
Despite the improvements in softness that can be gained from creping, however, additional improvements in softness would be beneficial to consumers. Therefore, what is lacking and needed in the art is a process for further improving the softness of creped throughdried tissue products.
Summary of the Invention It has now been discovered that the texture of creped, throughdried tissue products can be improved by processing the tissue web through a soft-nip calendering unit with the fabric side of the web oriented toward a resilient roll and the air side of the web oriented toward a smooth roll. More specifically, in one embodiment the invention concerns a method for making a throughdried tissue sheet comprising the steps ofdepositing an aqueous suspension of papermaking fibers onto an endless forming fabric to form a wet web, and then transferring the wet web to a throughdrying fabric. The wet web is described herein as having a fabric side, which is the surface that is in contact with the throughdrying fabric, and an opposite air side, which is the surface that is facing away from the throughdrying fabric. The wet web is then carried over a throughdryer to dry the web, transferred to a Yankee dryer, and creped from the Yankee dryer. The creped web is then calendered in a calendering unit comprising a smooth calendering roll and a resilient calendering roll having a Shore A surface hardness of about 75 to about 100 Durometer. During calendering, the creped web is oriented such that the fabric side is disposed toward the resilient calendering roll.
In another embodiment, the method of making a throughdried tissue sheet also comprises the step of embossing the creped web in an embossing unit comprising apattern roll and a backing roll. In the embossing unit, the creped web is oriented such that the fabric side of the web is disposed toward the pattern roll.
The improved softness is particularly pertinent to creped throughdried tissue products, which typically have larger creping features than a comparable wet pressed sheet. Moreover, the oriented soft-nip embossing is advantageously used in conjunction with oriented embossing of the tissue web. In particular, the resilient backing roll of the embossing unit is against the opposite surface of the tissue sheet as is the resi~ient calendering roll.
Applicants have examined the texture of tissue products to determine the attributes that result in a tissue product being considered soft. One attribute of a surface of a tissue that is indicative of the softness of the tissue is referred to as the Fuzzy attribute of the tissue surface. Contrariwise, attributes of a tissue surface that are counter-indicative of the softness of the tissue are referred to as the Gritty and Grainy attributes of the tissue surface.
The methods disclosed herein have been found to increase the Fuzzy attribute of the fabric side of the tissue product and reduce the Gritty and Grainy textures of the air side of the tissue product. The Fuzzy attribute is increased, particularly on the fabric side, as a result of frictional forces in the calendering nip caused by the speed differential at the contact point between the resilient calendering roll and the steel calendering roll. The creping process causes the air side of the tissue web to have pointed crepe structures such as ripples or ridges which result in Gritty and Grainy textures, and that contact between the steel calendering roll and the air side tends to flatten the pointed crepe structures present on the air side, thereby reducing the Gritty and Grainy textures. In addition, it is hypothesized that the clarity of the embossing pattern is improved because of an increase in opacity caused by calendering the sheet.
The result of the selective orientation and distinctive treatment of the opposite surfaces of the creped throughdried tissue is an embossed tissue web with enhanced softness.
For purposes herein, a "tissue web" or "tissue sheet" is a cellulosic web suitable for making or use as a facial tissue, bath tissue, paper towels, napkins, or the like. It can be layered or unlayered, creped or uncreped, and can consist of a single ply or multiple plies. In addition, the tissue web can contain reinforcing fibers for integrity and strength.
Tissue webs suitable for use in accordance with this invention are characterized by being absorbent, of low density and relatively fragile, particularly in terms of wet strength. Densities are typically in the range of from about 0.1 to about 0.3 grams per cubic centimeter. Absorbency is typically about 5 grams of water per gram of fiber, and generally from about 5 to about 9 grams of water per gram of fiber. Wet tensile strengths are generally about 0 to about 300 grams per inch of width and typically are at the low end of this range, such as from about 0 to about 30 grams per inch. Dry tensile strengths in the machine direction can be from about 100 to about 2000 grams per inch of width, preferably from about 200 to about 350 grams per inch of width. Tensile strengths in the cross-machine direction can be from about 50 to about 1000 grams per inch of width, preferably from about 100 to about 250 grams per inch of width. Dry basis weights are generally in the range of from about 5 to about 60 pounds per 2880 square feet. The-tissue webs referred to above are preferably made from natural cellulosic fiber sources such as hardwoods, softwoods, and nonwoody species, but can also containsignificant amounts of recycled fibers, sized or chemically-modified fibers, or synthetic fibers.
Tissue sheets which particularly benefit from the method of this invention are premium quality throughdried tissue sheets which have a relatively high degree of resiliency and low stiffness. The basis weight of the tissue sheet can be from about 5 to about 70 grams per square meter.
Referring now to the tissue making process of this invention, the forming process and tackle can be conventional as is well known in the papermaking industry. Such formation processes include Fourdrinier, roof formers such as a suction breast roll, gap formers such as twin wire formers and crescent formers, and other suitable formers. A
twin wire former may be preferred for higher speed operation. Forming wires or fabrics can also be conventional, the finer weaves providing greater fiber support and a smoother sheet and the coarser weaves providing greater bulk. Headboxes used to deposit the fibers onto the forming fabric can be layered or nonlayered, although layered headboxes are advantageous because the properties of the tissue can be finely tuned by altering the composition of the various layers. The throughdryers and throughdrying fabrics can also be of a conventional nature.
Brief DescriPtion of the Drawings Figure 1 is a schematic process flow diagram illustrating a method of making a creped throughdried web and winding the web into a parent roll.
Figure 2 is a schematic process flow diagram for a method of converting the tissue web using a calendering unit and an embossing unit.
Figure 3 representatively shows exemplary calendering and embossing units used in the converting process shown in Figure 2.
Figure 4 representatively shows a plan view of a portion of the surface of an exemplary pattern roll used in the embossing unit shown in Figure 3.
Figure 5 representatively shows a graph of data collected as part of a sensory panel evaluation pertaining to Examples 1 - 3 described below.
Detailed DescriPtion of the Drawings A method for carrying out the present invention is show in greater detail in theprocess flow diagram of Figure 1. A headbox 10 deposits an aqueous suspension ofpapermaking fibers onto the surface of a forming fabric 11. The resulting wet web 12 is transferred to an optional fine mesh transfer fabric 13 and thereafter transferred to a coarse mesh throughdryer fabric 14. In the illustrated process, two throughdryers 16 and 17 are used to dry the web 12. The web 12 may be partially dried in the first throughdryer 16 to a consistency of about 45 percent. The partially dried web 12 is then carried over the second throughdryer 17 and further dried to a consistency of about 85 to about 95 percent.
The tissue web 12 has opposite major planar surfaces which are referred to herein as the air side 18 and the fabric side 20. The air side 18 of the tissue web 12 is the surface of the web that faces away from the throughdryer fabric 14 and the surfaces of the throughdryers 16 and 17. Correspondingly, the fabric side 20 is the surface that is directed toward and placed in contact with the throughdryer fabric 14.
Upon exiting the second throughdryer, the web 12 is transferred to a fine mesh fabric 21 and pressed onto the surface of a Yankee dryer 22 for final drying, ifnecessary. The fabric side 20 of the web 12 is disposed against the surface of the Yankee. The web 12 is dislodged from the Yankee dryer 22 with a doctor (creping)blade 23 to produce a creped tissue web 24 that is wound into a parent roll 26.
For simplicity, the various tensioning rolls schematically used to define the several fabric runs are shown but not numbered. It will be appreciated that variations from the apparatus and method illustrated in Figure 1 can be made without departing from the scope of the invention. For example, additional dewatering of the wet web can be carried out, such as by vacuum suction, while the wet web is supported by theforming fabric; only a single throughdryer may be used; or the like.
Figure 2 illustrates an off-line converting operation to calender and emboss thecreped tissue web 24 in accordance with the present invention. The tissue web 24 is unwound from a parent roll 26 and transported in sequence to a calendering unit 30 and an embossing unit 40. The calendered and embossed tissue web 24 may then be wound at a rewinding unit 60. For example, the tissue web 24 may be wound onto tissue roll cores to form logs, which are subsequently cut into appropriate widths and the resulting individual tissue rolls are packaged (not shown).
Exemplary calendering and embossing units 30 and 40 are shown in greater detail in Figure 3. Note that in the winding and unwinding processes of Figures 1 and 2, the orientation of the tissue web 24 in the illustrated embodiment has been reversed so that the fabric side 20 of the tissue web is shown on the top and the air side 18 is shown on the bottom in Figures 2 and 3. Arrows are used to designate the direction of web travel through the calendering and embossing units 30 and 40.
The calendering unit 30 comprises a pair of calendering rolls 32 and 34 that together define therebetween a calendering nip 36. A spreader roll 38 is shown preceding the calendering nip 36, although other details of the calendering unit 30 are not shown for purposes of clarity.
The calendering nip 36 is a "soft-nip" wherein the rolls have different surface hardnesses and at least one of the rolls has a resilient surface. Resilient calendering rolls suitable for the present invention are typically referred to as rubber covered calendering rolls, although the actual material may comprise natural rubber, synthetic rubber, composites, or other compressible surfaces. Suitable resilient calendering rolls may have a Shore A surface hardness from about 75 to about 100 Durometer (approximately 0 to 55 Pusey & Jones), and particularly from about 85 to about 95 Durometer (approximately 10 to 40 Pusey & Jones). For instance, the calendering rolls may comprise a smooth steel roll 34 and a smooth resilient roll 32 formed of a composite polymer with a Shore A surface hardness of about 90 Durometer (approximately 25 - 30 Pusey & Jones). The calendering nip pressure is suitably from about 30 to about 200 pounds per lineal inch, and more particularly from about 75 to about 175 pounds per lineal inch.
Upon exiting the calendering unit 30, the tissue web 24 is transported to an embossing unit 40 comprising a pattern roll 42 and a backing roll 44. The pattern and backing rolls 42 and 44 together define therebetween an embossing nip 46. A spreader roll 48 is shown preceding the embossing nip 46, although other details of the calendering unit 30 are not shown for purposes of clarity.
Embossing is a well-known mechanism to increase sheet caliper, and it also provides an additional benefit by imparting a decorative pattern to the tissue product.
These decorative patterns are commonly formed by "spot embossing", which involves discrete embossing elements that are about 0.5 inch by 0.5 inch to about 1 inch by 1 inch in size, and thus from about 0.25 to about 1 square inch in surface area. These discrete embossing elements are typically spaced about 0.5 inch to about 1 inch apart.
The spot embossing elements are formed on a pattern roll, which is also referred to as an embossing roll, and are pressed into the tissue sheet.
A plan view of a portion of the surface of an exemplary pattern roll 42 is shown in Figure 4. The surface of the pattern roll 42 includes a plurality of discrete male spot embossing elements 50 that are separated by smooth land areas 52. The male spot embossing elements 50 define a decorative pattern, which in the illustrated embodiment is a series of cotton balls. The male spot embossing elements 50 may comprise a plurality of separate embossing element segments 54 which are raised above the surface of the land areas 52. Each cotton ball depicted in Figure 4 is a spot embossing element 50 comprising ten individual embossing element segments 54.
The spaced-apart discrete spot embossing elements or embossments can depict flowers, leaves, birds, animals, and the like. The pattern roll 42 may be formed by engraving or other suitable techniques.
In particular embodiments, the male embossing element segments 54 protrude from the surface of the embossing roll a distance or height which may be greater than about 0.04 inch, such as from about 0.045 inch to about 0.060 inch, for example about 0.045 inch. This relatively large element height enhances the embossing pattern definition. The width of the embossing element at its tip can be from about 0.005 to about 0.50 inch. The sidewall angle of the male embossing element segments measured relative to the plane tangent to the surface of the roll at the base of the embossing element is suitably from about 90 degrees to about 130 degrees.
As disclosed in copending U.S. Patent Application Serial No. unassigned, filed on even date herewith by Z. Salman et al. and titled "Calendered And Embossed Tissue Products," high-bulk tissue products can be embossed with improved pattern clarity by processing the high bulk tissue webs sequentially through separate calendering and embossing units. This multiple step converting process provides a method of optimizing the balance between sheet caliper for winding tension and embossing element height for pattern definition. The result is an embossed, high-bulk tissue product with improved embossing pattern clarity.
As used herein, the term "pattern definition" refers to the extent to which the embossed pattern can be immediately identified by distinct impressions made by the embossing element. The term "pattern clarity" as used herein refers to the clearness of the pattern in the final product.
The backing roll 44 may comprise a smooth rubber covered roll, an engraved roll such as a steel roll matched to the pattern roll, or the like. The bonding nip may be set to a pattern/backing roll loading pressure from about 80 to about 150 pounds per lineal inch, for example an average of about 135 pounds per lineal inch, such that the embossing pattern is imparted to the tissue web 24. The backing roll can be any material that meets the process requirements such as natural rubber, synthetic rubber or other compressible surfaces, and may have a Shore A surface hardness from about 65 to about 85 Durometer, such as about 75 Durometer.
ExamPles The following Examples are provided to give a more detailed understanding of theinvention. The particular amounts, proportions, compositions and parameters are meant to be exemplary, and are not intended to specifically limit the scope of the invention. In order to better compare the effects of the orientation of the fabric and air sides of the throughdried tissue, none of the Example sheets were embossed. The converting lines all ran at 1000 feet per minute.
Example 1. (ComParative) A throughdried and creped tissue sheet was manufactured having a caliper of 0.010 inch and a basis weight of about 15.2 pounds per 2880 square feet. The tissue sheet was slit into narrow rolls for use on converting lines. A narrow roll of the throughdried and creped tissue was unwound and then rewound as a control. Basesheet samples were prepared for sensory evaluation from this converted roll. Thus, the tissue sheet of Example 1 was not calendered.
Example 2. (Comcarative) For Example 2, a narrow roll of throughdried and creped tissue as described in Example 1 was unwound, calendered, and then rewound.
Basesheet samples were prepared for sensory evaluation from this converted roll.The calendering unit comprised a smooth steel calendering roll and a smooth resilient calendering roll. The resilient calendering roll had an exterior covering formed of a composite polymer from Stowe Woodward Company, U.S.A., under the tradename MULTICHEM, with a Shore A hardness of 90 Durometer. The calendering nip was set to 30 pounds per lineal inch.
The tissue sheet was processed through the calendering nip such that the fabric side of the sheet was disposed against the steel calendering roll and the air side was disposed against the resilient calendering roll.
Exam~le 3. For Example 3, a narrow roll of throughdried and creped tissue as described in Example 1 was unwound, calendered, and then rewound. Basesheet samples were prepared for sensory evaluation from this converted roll. The components of the calendering unit and the operating conditions were the same asdescribed in Example 2, although the positions of the steel calendering roll and the resilient calendering roll were transposed.
Thus, in Example 3 the tissue sheet was processed through the calendering nip such that the fabric side of the sheet was disposed against the resilient calendering roll and the air side was disposed against the steel calendering roll.
The bath tissue sheets of Examples 1, 2 and 3 were submitted for sensory panel evaluation. The sensory panel utilized eleven individuals trained to compare tissue products and evaluate tactile properties. The panelists were asked to render numerical values for each Example tissue regarding the following attributes: Fuzzy attribute for both the air side and the fabric side; Gritty attribute for both the air side and the fabric side; Grainy attribute for both the air side and the fabric side; stiffness; and thickness.
For each Example bath tissue, the tissue samples were die cut from the rolls to 8 by 4.5 inches.
The Fuzzy attribute was ranked on a scale from O described as none/bald to 7 described as much/fuzzy. The panelists were asked to consider the amount of fibers, pile, fiber, nap, and fuz on the tissue surface. The panelists were instructed to: place a single tissue sample flat on a smooth tabletop with the side to be tested facing up; and using the pads of the index and middle fingers, move in quarter-sized circular motions very lightly across several areas of the sample.
The Gritty attribute was ranked on a scale from O described as smooth to 7 described as gritty. The panelists were asked to consider the amount of sharp, prickly, abrasive particles or fibers felt on the surface of the sample. The panelists were instructed to: place a single tissue sample on a table with the side to be tested facing up; with forearm/elbow resting on the table and using the full length of the fingers, slowly glide your fingers lightly across the entire surface one inch from the edge moving left to right; use the other hand to rotate the tissue sample and stroke along all four directions;
and evaluate the grittiest direction.
The Grainy attribute was ranked on a scale from O described as smooth to 7 described as grainy. The panelists were asked to consider the pebbly texture of the tissue sample (feeling of grains of sand, rice), and to evaluate by considering the frequency, size, and hardness/firmness/rigidity of grains. It was noted that the panelist's perception can include shape, orientation and size of texture (pattern/embossing), small rounded particles, fibers, etc. The panelists were instructed to: place a single tissue sample on a table with the side to be tested facing up; with forearm/elbow resting on the table and using the pads of the index and middle fingers, slowly and gently move the pads of your fingers across the surface going slightly into the surface of the sample, one inch from the edge moving left to right; use the other hand to rotate the tissue sample and stroke along all four directions; and evaluate the grainiest direction.
Stiffness was ranked on a scale from O described as pliable/flexible to 7 described as stiff/rigid. The panelists were asked to consider the amount of pointed, rippled or cracked edges or peaks felt from the sample while turning in your hand. The panelists were instructed to: place 2 tissue samples flat on a smooth tabletop; the bath tissue samples should overlap one another by 0.5 inch and be flipped so that opposite sides of the tissue samples are represented during testing; with forearm/elbow resting on the table, place your open hand palm down on the samples; position your hand so your fingers are pointing toward the top of the samples approximately 1.5 inch from the edge; draw your fingers toward your palm with little or no downward pressure to gather the tissue samples; gently move the gathered samples around in the palm of your hand approximately 2-3 turns.
Thickness was ranked on a scale from O described as thin to 7 described as thick. The panelists were asked to consider the relative depth of tissue (perceived distance between thumb and one/two fingers). The panelists were instructed to: using a single sample piece, gently hold the tissue with thumb between your index and second fingers; with your other hand gently pull the tissue out of your hold; repeat this procedure several times on the lower edge of the tissue to evaluate the degree of thickness as your fingers come together off the edge of the tissue.
The data collected from the sensory panel analysis is presented in Table 1 belowand is graphically displayed in Figure 4. The attribute values represent averages of all of the panelists.
Table 1 Sensory Panel Profile Attribute ExamDle 1 Example2 Example 3 Fuzy 3.94 4.74 5.49 (air side) Fu~y 5.43 5.75 5.85 (fabric side) Gritty 3.56 2.25 1.98 (air side) Gritty 2.11 1.77 1.98 (fabric side) Grainy 2.55 1.41 1.35 (air side) Grainy 1.95 1.28 1.37 (fabric side) Stiffness 5.84 6.01 5.89 Thickness 4.31 4.26 4.35 Thus, the sensory panel comparisons indicate that soft-nip calendering with the fabric side oriented toward the resilient roll, represented by Example 3, increases the Fuzy attribute of softness more than soft-nip calendering with a transposed orientation of the calendering rolls, represented by Example 2. As noted previously, increasing the Fuzy attribute indicates improved softness. Because the Fuzzy value is greater on both the air side and the fabric side when the fabric side is oriented toward the resilient roll (Example 3), it follows that the overall softness of the tissue is better using this orientation.
The reduction of the Gritty and Grainy values on the air side of the tissue is aresult of flattened crepe folds. Soft-nip calendering with the fabric side oriented toward the resilient roll (Example 3) increases the Fuzzy attribute at a 95 percent confidence level and directionally decreases the Gritty and Grainy attributes, resulting in a less two-sided sheet as compared to both Examples 1 and 2.
It will be appreciated that the foregoing examples, given for purposes of illustration, are not to be construed as limiting the scope of this invention, which is defined by the following claims and all equivalents thereto.
Claims (14)
1. A method for making a throughdried tissue sheet, comprising:
depositing an aqueous suspension of papermaking fibers onto an endless forming fabric to form a wet web;
transferring the wet web to a throughdrying fabric, the wet web having a fabric side in contact with the throughdrying fabric and an opposite air side facing away from the throughdrying fabric;
carrying the wet web over a throughdryer to dry the web;
transferring the web to a Yankee dryer;
creping the web from the Yankee dryer; and calendering the creped web in a calendering unit comprising a smooth calendering roll and a resilient calendering roll, the resilient roll having a Shore A surface hardness of about 75 to about 100 Durometer, the creped web being oriented such that the fabric side is disposed toward the resilient calendering roll.
depositing an aqueous suspension of papermaking fibers onto an endless forming fabric to form a wet web;
transferring the wet web to a throughdrying fabric, the wet web having a fabric side in contact with the throughdrying fabric and an opposite air side facing away from the throughdrying fabric;
carrying the wet web over a throughdryer to dry the web;
transferring the web to a Yankee dryer;
creping the web from the Yankee dryer; and calendering the creped web in a calendering unit comprising a smooth calendering roll and a resilient calendering roll, the resilient roll having a Shore A surface hardness of about 75 to about 100 Durometer, the creped web being oriented such that the fabric side is disposed toward the resilient calendering roll.
2. The method of claim 1 wherein a calendering nip of the calendering unit applies a pressure of about 30 to about 200 pounds per lineal inch to the web.
3. The method of claim 2 wherein the calendering nip applies a pressure of about75 to about 175 pounds per lineal inch to the web.
4. The method of claim 1 wherein the resilient calendering roll has a Shore A
hardness of about 85 to about 95 Durometer.
hardness of about 85 to about 95 Durometer.
5. The method of claim 1 wherein the resilient calendering roll is a smooth, rubber covered roll.
6. A method for making a throughdried tissue sheet, comprising:
depositing an aqueous suspension of papermaking fibers onto an endless forming fabric to form a wet web;
transferring the wet web to a throughdrying fabric, the wet web having a fabric side in contact with the throughdrying fabric and an opposite air side facing away from the throughdrying fabric;
carrying the wet web over a throughdryer to dry the web;
transferring the web to a Yankee dryer;
creping the web from the Yankee dryer;
calendering the creped web in a calendering unit comprising a smooth calendering roll and a resilient calendering roll, the resilient roll having a Shore A surface hardness of about 75 to about 100 Durometer, the creped web being oriented such that the fabric side is disposed toward the resilient calendering roll; and embossing the creped web in an embossing unit comprising a pattern roll and a backing roll, the creped web being oriented such that the fabric side is disposed toward the pattern roll.
depositing an aqueous suspension of papermaking fibers onto an endless forming fabric to form a wet web;
transferring the wet web to a throughdrying fabric, the wet web having a fabric side in contact with the throughdrying fabric and an opposite air side facing away from the throughdrying fabric;
carrying the wet web over a throughdryer to dry the web;
transferring the web to a Yankee dryer;
creping the web from the Yankee dryer;
calendering the creped web in a calendering unit comprising a smooth calendering roll and a resilient calendering roll, the resilient roll having a Shore A surface hardness of about 75 to about 100 Durometer, the creped web being oriented such that the fabric side is disposed toward the resilient calendering roll; and embossing the creped web in an embossing unit comprising a pattern roll and a backing roll, the creped web being oriented such that the fabric side is disposed toward the pattern roll.
7. The method of claim 6 wherein a calendering nip of the calendering unit applies a pressure of about 30 to about 200 pounds per lineal inch to the web.
8. The method of claim 7 wherein the calendering nip applies a pressure of about75 to about 175 pounds per lineal inch to the web.
9. The method of claim 6 wherein the resilient calendering roll has a Shore A
hardness of about 85 to about 95 Durometer.
hardness of about 85 to about 95 Durometer.
10. The method of claim 6 wherein the embossing backing roll has a Shore A
surface hardness of from about 65 to about 85 Durometer.
surface hardness of from about 65 to about 85 Durometer.
11. The method of claim 6 wherein an embossing nip of the embossing unit applies a pressure of about 80 to about 150 pounds per lineal inch to the tissue web.
12. The method of claim 6 wherein the web is unwound from a roll prior to the calendering unit.
13. A method for making a throughdried tissue sheet, comprising:
depositing an aqueous suspension of papermaking fibers onto an endless forming fabric to form a wet web;
transferring the wet web to a throughdrying fabric, the wet web having a fabric side in contact with the throughdrying fabric and an opposite air side facing away from the throughdrying fabric;
carrying the wet web over a throughdryer to dry the web;
transferring the web to a Yankee dryer;
creping the web from the Yankee dryer;
winding the creped web to form a roll;
unwinding the roll and processing the unwound creped web sequentially through a calendering unit and an embossing unit, the calendering unit comprising a pair of smooth calendering rolls, one of the smooth calendering rolls being a resilient calendering roll having a Shore A surface hardness of about 75 to about 100 Durometer, the embossing unit comprising a pattern roll and a backing roll; and rewinding the calendered and embossed web;
wherein the creped web is oriented such that the fabric side is disposed toward the resilient calendering roll and toward the embossing pattern roll.
depositing an aqueous suspension of papermaking fibers onto an endless forming fabric to form a wet web;
transferring the wet web to a throughdrying fabric, the wet web having a fabric side in contact with the throughdrying fabric and an opposite air side facing away from the throughdrying fabric;
carrying the wet web over a throughdryer to dry the web;
transferring the web to a Yankee dryer;
creping the web from the Yankee dryer;
winding the creped web to form a roll;
unwinding the roll and processing the unwound creped web sequentially through a calendering unit and an embossing unit, the calendering unit comprising a pair of smooth calendering rolls, one of the smooth calendering rolls being a resilient calendering roll having a Shore A surface hardness of about 75 to about 100 Durometer, the embossing unit comprising a pattern roll and a backing roll; and rewinding the calendered and embossed web;
wherein the creped web is oriented such that the fabric side is disposed toward the resilient calendering roll and toward the embossing pattern roll.
14
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US87654897A | 1997-06-16 | 1997-06-16 | |
| US08/876,548 | 1997-06-16 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2236829A1 true CA2236829A1 (en) | 1998-12-16 |
Family
ID=25367988
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2236829 Abandoned CA2236829A1 (en) | 1997-06-16 | 1998-06-09 | Sheet orientation for soft-nip calendering and embossing of creped throughdried tissue products |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2236829A1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6712930B2 (en) | 2000-07-10 | 2004-03-30 | Metso Paper, Inc. | Method for calendering tissue paper |
-
1998
- 1998-06-09 CA CA 2236829 patent/CA2236829A1/en not_active Abandoned
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6712930B2 (en) | 2000-07-10 | 2004-03-30 | Metso Paper, Inc. | Method for calendering tissue paper |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US6248211B1 (en) | Method for making a throughdried tissue sheet | |
| CA1093879A (en) | Forming absorbent tissue paper products with fine mesh fabrics | |
| EP0029269B1 (en) | Layered paper having a soft and smooth velutinous surface, and method of making such paper | |
| JP3748884B2 (en) | Soft tissue | |
| US20070137814A1 (en) | Tissue sheet molded with elevated elements and methods of making the same | |
| US6464829B1 (en) | Tissue with surfaces having elevated regions | |
| AU2017262480B2 (en) | Textured subtractive patterning | |
| EP3934904B1 (en) | Embossed multi-ply tissue products | |
| US11111633B2 (en) | Tissue products having macrofolds | |
| US20230119448A1 (en) | Embossed multi-ply tissue products | |
| US6478927B1 (en) | Method of forming a tissue with surfaces having elevated regions | |
| AU2017262479B2 (en) | Patterned tissue product | |
| US20220154409A1 (en) | Embossed multi-ply tissue product | |
| CA2236829A1 (en) | Sheet orientation for soft-nip calendering and embossing of creped throughdried tissue products | |
| CA2313378A1 (en) | Method for making a throughdried tissue sheet | |
| MXPA98004731A (en) | Leaf orientation for soft pressure calender calendaring and recording of continuous drying tisu products | |
| MXPA00007412A (en) | Method for making a throughdried tissue sheet | |
| AU2001283557B2 (en) | Non planar tissue paper | |
| MXPA99004273A (en) | Tisu of paper that has a better softness |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Dead |