Patent Application
20080200320
The present invention is directed to the field of paper converting. More particularly, the present invention is directed toward processing rolls having an elastomeric coating disposed thereon.
Web-based products, including paper products such as paper towels, bathroom tissues, facial tissues, paper napkins, and the like are widely used by consumers on a daily basis for a variety of household needs. These paper products may be embossed to increase the bulk, absorbency, softness, and aesthetic appeal of the final product.
Web substrates, such as paper webs that are used to make such web-based paper products, can be embossed. The embossing of web substrates can provide improvements to the resulting web substrate, such as increased bulk, improved water holding capacity, improved aesthetics, as well as assist in holding superposed plies of a web-based product together. Both single ply and multiple ply (or multi-ply) web substrates can be embossed. Multi-ply paper webs are web substrates that include at least two plies superimposed in face-to-face relationship to form a layered structure.
During a typical embossing process, a web substrate (or web) is fed through a nip formed between juxtaposed (generally axially) rolls or cylinders. Embossing protrusions on one, or both, of the rolls can compress and/or deform the web. If a typical multi-ply product is being formed, two or more plies are fed through the nip and regions of each ply are brought into a contacting relationship with the opposing ply. The embossed regions of the plies may produce an aesthetic pattern and provide a means for joining and maintaining the plies in face-to-face contacting relationship.
Embossing can be performed by one of several processes: knob-to-rubber impression, knob-to-knob embossing, or nested embossing. Knob-to-rubber (also referred to as rubber-to-steel) embossing typically comprises two rolls—a hard embossing roll having emboss protrusions, or emboss knobs, disposed in a desired pattern thereon, and a back-side soft impression roll. As the paper web is passed through the nip formed between the rolls, the emboss knobs impress the web against and into the back-side soft impression roll to deform the overall structure, and resulting appearance, of the web.
The soft impression roll used in such an embossing process can be constructed using a solid core covered by a rubber or rubberized roll cover formed from an elastomer. Exemplary elastomers may include natural rubber or synthetic elastomers such as neoprene, styrene-butadiene (SBR), nitrile, or chlorosulfonated polyethylene. Because elastomers are typically versatile materials, elastomeric covers can be used in a variety of papermaking applications. For example, rubber covers may be used in smoothing press rolls employed in the press section of a papermaking machine, in the dryer section of a papermaking machine in size press rolls, in breaker stack press rolls (in which non-uniformities in a web substrate are flattened or removed), or in a paper converting process (such as embossing).
It can be desirable for elastomeric covers employed in papermaking machines to meet certain minimum strength, elastic modulus, temperature and liquid resistance to survive the papermaking environment. Elastomeric covers used for the purposes listed above must often have different properties (such as hardness or modulus) depending on the specific purpose that it is being used for. Within each use, such as paper converting, there may be a myriad of parameters that may be used depending on the specific goal that is desired to be achieved.
The present invention improves upon the depth, crispness, and clarity of an embossment over the rubber-to-steel embossing of the prior art. Some prior art approaches attempt to achieve deep, crisp, and clear embossments involve increasing the softness and/or thickness of the elastomeric roll cover on the converting roll because it is thought that a soft, thick, and easily deformable elastomeric roll cover will allow steel emboss protrusions to ‘mold’ into the elastomeric roll and deliver a desirable product. However, this turns out not to be the case. Accordingly, the present invention takes an alternative route and, rather than using a soft and thick rubber roll cover, uses a harder, thinner elastomeric roll cover. Without being limited by theory, it is thought that by increasing hardness and decreasing thickness of the elastomeric roll cover, an increase in the nip width between the rubber roll and the emboss roll will result. Consequently, an increased pressure between the converting roll and the emboss roll results that can provide deep, crisp, and clear embossments that are significantly improved over the prior art.
One embodiment of the present invention provides a converting roll comprising a core and an elastomeric roll cover. The core has a radius ranging from about 1 inch (2.54 cm) to about 12 inches (30.48 cm) and an outer surface. The elastomeric roll cover has a hardness ranging from about 80 P&J to about 140 P&J and a thickness ranging from about 0.25 inches (6.35 mm) to about 1.25 inches (31.75 mm). The elastomeric roll cover is disposed about the outer surface of said core.
Another embodiment of the present invention provides a converting roll having a core, a base layer disposed about an outer surface of the core, and an elastomeric roll cover disposed about an outer surface of said base layer. The core has a radius ranging from about 1 inch (2.54 cm) to about 12 inches (30.48 cm). The base layer has a hardness ranging from about 0.5 P&J to about 3.0 P&J and a base layer radius ranging from about 4 inches (10.16 cm) to about 12 inches (30.48 cm). The elastomeric roll cover has a hardness ranging from about 80 P&J to about 140 P&J and a thickness ranging from about 0.25 inches (6.35 mm) to about 1.75 inches (44.5 mm).
Yet another embodiment of the present invention provides a converting roll having a core, a base layer disposed about a surface of the core, and an elastomeric roll cover disposed about a surface of the base layer. The core has a radius ranging from about 5 inches (12.7 cm) to about 10 inches (25.4 cm). The base layer has a hardness ranging from about 1.0 P&J to about 2.0 P&J and a base layer radius ranging from about 5 inches (12.7 cm) to about 11 inches (27.94 cm). The elastomeric roll cover has a hardness ranging from about 95 P&J (±5 P&J) to about 115 P&J (±5 P&J) and a thickness ranging from about 0.75 inches (1.91 cm) to about 1.25 inches (31.75 cm).
“Paper product,” as used herein refers to any formed, fibrous structure products, traditionally, but not necessarily, comprising cellulose fibers. In one embodiment, the paper products of the present invention include tissue-towel and/or paper products.
“Tissue and/or towel paper product” refers to creped and/or uncreped products comprising paper tissue or paper towel technology in general, including, but not limited to, conventional felt-pressed or conventional wet-pressed tissue paper, pattern densified tissue paper, starch substrates, and high bulk, uncompacted tissue paper. Exemplary, but non-limiting examples of tissue-towel paper products include paper toweling, facial tissue, bath tissue, table napkins, and the like.
“Ply” or “Plies,” as used herein, means an individual fibrous structure or sheet of fibrous structure, optionally to be disposed in a substantially contiguous, face-to-face relationship with other plies, forming a multi-ply fibrous structure. It is also contemplated that a single fibrous structure can effectively form two “plies” or multiple “plies”, for example, by being folded on itself. In one embodiment, the ply has an end use as a tissue and/or towel paper product. A ply may comprise one or more wet-laid layers, air-laid layers, and/or combinations thereof. If more than one layer is used, it is not necessary for each layer to be made from the same fibrous structure. Further, the layers may or may not be homogenous within a layer. The actual makeup of a tissue paper ply is generally determined by the desired benefits of the final tissue-towel paper product, as would be known to one of skill in the art. The fibrous structure may comprise one or more plies of non-woven materials in addition to the wet-laid and/or air-laid plies.
“Paper web,” as used herein, means an arrangement of fibers produced in any papermaking machine known in the art to create a ply of paper. “Fiber” means an elongate particulate having an apparent length greatly exceeding its apparent width. More specifically, and as used herein, fiber refers to such fibers suitable for a papermaking process.
“Basis Weight,” as used herein, is the weight per unit area of a sample reported in lbs/3000 ft2 or g/m2.
“Machine Direction” or “MD,” as used herein, means the direction parallel to the flow of the fibrous structure through the papermaking machine and/or product manufacturing equipment.
“Cross Machine Direction” or “CD,” as used herein, means the direction perpendicular to the machine direction in the same plane of the fibrous structure and/or fibrous structure product comprising the fibrous structure.
“Embossing,” as used herein, refers to the process of deflecting a relatively small portion of a cellulosic fibrous structure normal to its plane and impacting the projected portion of the fibrous structure against another surface to permanently disrupt the fiber to fiber bonds.
“Converting roll,” as used herein is a roll that may be used in the paper embossing process for accepting the protrusions from a male embossing roll. In some embodiments, the converting roll comprises an elastomeric roll cover and a core. In other embodiments, the converting roll comprises an elastomeric roll cover, base layer, and core.
“Roll cover,” as used herein, refers to a cover that can be disposed upon, and releasably attached to, the external surface of a converting, steel or other metal or solid core roll. The roll cover can be made of any material known in the art.
“Rubber roll cover” also known to those in the art as an “elastomeric roll cover,” as used herein, refers to a roll cover that is constructed from rubber or an elastomer.
“Hardness,” as used herein, refers to the stiffness of a material as characterized by the difference in penetration depth of the material using a ball of a specified dimension under two conditions of contact. First, using a small initial force and second, using a much larger final force. The differential penetration is taken at a specified time and converted to a hardness scale value. Hardness, as described herein is described in units of Pusey & Jones (P&J). The hardness may be measured by the American Society for Testing and Materials (ASTM) standard #D531-00 (2005).
Rubber-to-steel embossing is equally applicable to all types of consumer paper products such as paper towels, toilet tissue, facial tissue, napkins, and the like. Further, rubber-to-steel embossing may be used on paper webs formed from a variety of paper making fibers such as natural fibers, synthetic fibers, as well as any other suitable fibers, starches, and combinations thereof. Paper making fibers useful in the present invention include cellulosic fibers commonly known as wood pulp fibers. Applicable wood pulps include chemical pulps, such as Kraft, sulfite and sulfate pulps; mechanical pulps including groundwood, thermomechanical pulp; chemithermomechanical pulp; chemically modified pulps, and the like. Chemical pulps, however, may be preferred in tissue towel embodiments since they are known to those of skill in the art to impart a superior tactical sense of softness to tissue sheets made therefrom. Pulps derived from deciduous trees (hardwood) and/or coniferous trees (softwood) can be utilized herein. Such hardwood and softwood fibers can be blended or deposited in layers to provide a stratified web. Exemplary layering embodiments and processes of layering are disclosed in U.S. Pat. Nos. 3,994,771 and 4,300,981. Additionally, fibers derived from non-wood pulp such as cotton linters, bagesse, and the like, can be used. Additionally, fibers derived from recycled paper, which may contain any or all of the pulp categories listed above, as well as other non-fibrous materials such as fillers and adhesives used to manufacture the original paper product may be used in the present web. In addition, fibers and/or filaments made from polymers, specifically hydroxyl polymers, may be used in the present invention. Non-limiting examples of suitable hydroxyl polymers include polyvinyl alcohol, starch, starch derivatives, chitosan, chitosan derivatives, cellulose derivatives, gums, arabinans, galactans, and combinations thereof. Additionally, other synthetic fibers such as rayon, lyocel, polyester, polyethylene, and polypropylene fibers can be used within the scope of the present invention. Further, such fibers may be latex bonded. Other materials are also intended to be within the scope of the present invention as long as they do not interfere or counter act any advantage presented by the instant invention.
Synthetic fibers useful herein include any material, such as, but not limited to, those selected from the group consisting of polyesters, polypropylenes, polyethylenes, polyethers, polyamides, polyhydroxyalkanoates, polysaccharides, and combinations thereof. The synthetic fiber may comprise a polymer. The polymer may be any material, such as, but not limited to, those materials selected from the group consisting of polyesters, polyamides, polyhydroxyalkanoates, polysaccharides and combinations thereof. More specifically, the material of the polymer segment may be selected from the group consisting of poly(ethylene terephthalate), poly(butylene terephthalate), poly(1,4-cyclohexylenedimethylene terephthalate), isophthalic acid copolymers (e.g., terephthalate cyclohexylene-dimethylene isophthalate copolymer), ethylene glycol copolymers (e.g., ethylene terephthalate cyclohexylene-dimethylene copolymer), polycaprolactone, poly(hydroxyl ether ester), poly(hydroxyl ether amide), polyesteramide, poly(lactic acid), polyhydroxybutyrate, and combinations thereof.
Further, the synthetic fibers can be a single component (i.e., single synthetic material or mixture makes up entire fiber), bi-component (i.e., the fiber is divided into regions, the regions including two or more different synthetic materials or mixtures thereof and may include co-extruded fibers) and combinations thereof. It is also possible to use bicomponent fibers, or simply bicomponent or sheath polymers. Non-limiting examples suitable bicomponent fibers are fibers made of copolymers of polyester (polyethylene terephthalate)/polyester (polyethylene terephthalate) (otherwise known as “CoPET/PET” fibers), which are commercially available from Fiber Innovation Technology, Inc., Johnson City, Tenn. These bi-component fibers can be used as a component fiber of the structure, and/or they may be present to act as a binder for the other fibers present. Any or all of the synthetic fibers may be treated before, during, or after the process of the present invention to change any desired properties of the fibers. For example, in certain embodiments, it may be desirable to treat the synthetic fibers before or during the papemmaking process to make them more hydrophilic, more wettable, etc.
The fibrous structure may comprise a tissue-towel paper product known in the industry. Exemplary, but non-limiting, embodiments of these substrates may be made according U.S. Pat. Nos. 4,191,609; 4,300,981; 4,514,345; 4,528,239; 4,529,480; 4,637,859; 5,245,025; 5,275,700; 5,328,565; 5,334,289; 5,364,504; 5,527,428; 5,556,509; 5,628,876; 5,629,052; 5,637,194; 5,411,636; EP 677612; and U.S. Patent Application 2004/0192136A1.
The fibrous structure substrates may be manufactured via a wet-laid making process where the resulting web may be comprised of fibrous structure selected from the group consisting of: through-air-dried fibrous structure plies, differential density fibrous structure plies, wet laid fibrous structure plies, air laid fibrous structure plies, conventional fibrous structure plies, and combinations thereof.
Optionally, the fibrous structure substrate may be foreshortened by creping or by wet microcontraction. Creping and/or wet microcontraction are disclosed in U.S. Pat. Nos. 6,048,938; 5,942,085; 5,865,950; 4,440,597; 4,191,756; and 6,187,138.
The substrate which comprises the fibrous structure of the present invention may be cellulosic, non-cellulosic, or a combination of both. The substrate may be conventionally dried using one or more press felts or through-air dried. If the substrate which comprises the paper according to the present invention is conventionally dried, it may be conventionally dried using a felt which applies a pattern to the paper as taught by commonly assigned U.S. Pat. No. 5,556,509 and PCT Application WO 96/00812. The substrate which comprises the paper according to the present invention may also be through air dried. A suitable through air dried substrate may be made according to commonly assigned U.S. Pat. No. 4,191,609.
In one embodiment, the substrate which comprises the paper according to the present invention is through air dried on a belt having a patterned framework. The belt according to the present invention may be made according to any of commonly assigned U.S. Pat. Nos. 4,637,859; 4,514,345; 5,328,565; and 5,334,289.
In one exemplary embodiment, the core 20 can be a substantially cylindrical structure typically formed of steel or other metal. In certain embodiments, the core 20 is from about 10 inches (25.4 cm) to about 22 inches (55.9 cm) in diameter. In another embodiment, the core is from about 12 inches (30.5 cm) to about 20 inches (50.8 cm) in diameter. In one embodiment, the core is about 19.6 inches (49.8 cm) in diameter. In another embodiment, the core is about 12.5 inches (31.8 cm) in diameter. In certain embodiments the core 20 can be hollow and in certain other embodiments the core 20 can be solid.
In certain embodiments, the outer surface 13 of the base layer 12 and/or the inner surface of the elastomeric roll cover 16 and/or outer surface 21 of the core 20 may be treated by blasting, sanding, sandblasting, chemically treated, or the like to prepare the respective surface for application of a bonding agent.
In the embodiment shown in
In the embodiment shown in
Alternatively, a converting roll 10 comprising an elastomeric roll cover 16 disposed about a core 20 or a base layer containing converting roll 11 comprising an elastomeric roll cover 16 disposed about a base layer 12 and a core 20 may be purchased from a vendor such as Xerium Technologies, Inc/Stowe Woodward (Youngsville, N.C.), Valley Roller Company, Inc. (Appleton, Wis.), American Roller Co. (Union Grove, Wis.).
The converting roll 10 or base layer containing converting roll 11 may have a total radius, RT, measured from the center point C of the converting roll 10 or base layer containing converting roll 11 to the outer surface of the elastomeric roll cover 16 of from about 4 inches (10.2 cm) to about 14 inches (35.6 cm). In another embodiment, RT is from about 5 inches (12.7 cm) to about 12 inches (30.5 cm). In a preferred embodiment, RT is about 6.5 inches (16.5 cm). In another embodiment, RT is about 11 inches (27.5 cm).
In one preferred embodiment, the longitudinal axis of converting roll 10 is preferably aligned parallel to the longitudinal axis of emboss roll 30. A paper web 40 is then passed through the nip 50 formed between the converting roll 10 and the emboss roll 30. Emboss roll 30 can be provided with a plurality of embossing knobs that effectively impress the paper web 40 into the elastomeric roll cover 16 disposed upon converting roll 10 at the nip 50 to deform the structure of the paper web 40. The nip 50 width, WN, is the width of the nip 50. In a preferred embodiment, the converting roll 10 and emboss roll 30 are disposed so that a compressive force exists therebetween. In this manner, the compressive force due to the pressures produced between converting roll 10 and emboss roll 30 can be applied to the paper web 40 disposed therebetween. In one embodiment, the nip width, WN, of the present invention is from about 1 inch (2.54 cm) to about 2.5 inches (6.35 cm). In one embodiment, the pressure at the nip 50 of the present invention is from about 55 psi (37.9 MPa) to about 440 psi (303 MPa). It was found that the relationship between calendar nip with (WN), the nip 50 load, converting roll 10 and emboss roll 30 dimensions, and the physical properties of elastomeric roll cover 16 follows the relationship:
where:
WN is the nip 50 width in inches;
L is the nip 50 load in pounds per linear inch (PLI);
T is the thickness of the elastomeric roll cover 16 in inches;
D1 is the converting roll 10 diameter in inches;
D2 is the embossing roll 30 diameter in inches; and,
P is the hardness of the elastomeric roll cover 16 in units of P&J.
An emboss roll 30 that may be used in the present invention may comprise one or more protrusions 70. Without desiring to be limited by theory, the force applied to the paper web 40, as well as the distribution of the resulting pressure on the surface of the paper web 40, is directly affected by the shape of the surface of a protrusion 70 contacting the paper web 40 as well as the overall surface area of a protrusion 70 contacting the paper web 40.
In one embodiment of the present invention, the design is optimized such the relationship between the thickness and the hardness of the elastomeric roll cover 16 provides deep, crisp, and clear embossments. Without being limited by theory, it is thought that to provide effective pressure at the nip 50, the elastomeric roll cover 16 is preferably hard and thin rather than soft and thick. In one embodiment, the hardness of the elastomeric roll cover is from about 80 P&J (±5 P&J) to about 140 P&J (±5 P&J). In another embodiment, the hardness is from about 90 P&J (±5 P&J) to about 130 P&J (+5 P&J). In another embodiment, the hardness is from about 95 P&J (±5 P&J) to about 115 P&J (±5 P&J). In one embodiment, the elastomeric roll cover 16 has a thickness, TR, ranging from about 0.25 inches (6.35 mm) to about 1.75 inches (44.45 mm). In another embodiment, the elastomeric roll cover 16 thickness, TR, is from about 0.5 inches (12.7 mm) to about 1.5 inches (38.1 mm). In another embodiment, the elastomeric roll cover 16 thickness is from about 0.75 inches (19.05 mm) to about 1.25 inches (31.75 mm).
One of skill in the art may appreciate that it is possible to construct an elastomeric roll cover 16 using different materials depending on the intended function of the particular roll. Using an elastomeric roll cover 16 on the converting roll 10 can allow for quicker and less expensive reconditioning of the converting roll 10 than replacing the entire converting roll 10. When a roll cover is damaged or worn, it may be reground easily, or stripped from the converting roll 10 and replaced at lower cost than replacing the entire converting roll 10. By using different roll cover materials and formulations, the surface characteristics of the converting roll 10 can be optimized for the location in the machine in which the converting roll 10 is installed. Thus, desired and necessary hardness, abrasion and wear resistance, chemical resistance and other properties can be achieved. Both natural rubbers and synthetic elastomers have been used in paper converting roll covers. It also is known to use a plurality of different materials in layers between the roll shell and the top layer of the roll cover, as transition layers between the shell and the top layer, to promote roll cover life. Examples of roll covers are shown in U.S. Pat. Nos. 5,887,517; 6,173,496; 6,874,232; and 7,008,513. In addition, synthetic fiber or particle fillers have been used mixed with the elastomer to improve paper machine roll performance, and to increase roll cover life. Examples of such fiber or particle fillers are shown in U.S. Pat. No. 6,918,865.
Alternatively, a suitable elastomeric roll cover 16 may be purchased from a commercial vendor such as Xerium Technologies, Inc/Stowe Woodward (Youngsville, N.C.), Valley Roller Company, Inc. (Appleton, Wis.), American Roller Co. (Union Grove, Wis.).
The core 20 may be constructed from any material known in the art. Nonlimiting examples of materials that may be used are described in U.S. Pat. Nos. 6,445,906; 4,178,664; 4,998,333; and 5,091,027. A suitable hard core 20 may also be readily available through a variety of vendors, such as Xerium Technologies, Inc/Stowe Woodward (Youngsville, N.C.), Valley Roller Company, Inc. (Appleton, Wis.), American Roller Co. (Union Grove, Wis.).
In one embodiment, the core 20 has a radius, Rc, of from about 1 inch (2.54 cm) to about 12 inches (30.48 cm). In another embodiment, the core has a radius of from about 2.5 inches (6.35 cm) to about 10 inches (25.4 cm). In another embodiment, the core has a radius of from about 5 inches (12.7 cm) to about 10 inches (25.4 cm). In another embodiment, the core has a radius of from about 6 inches (15.24 cm) to about 8 inches (20.32 cm).
The base layer 12 of the present invention may be made from any material known in the art. A base layer may be obtained commercially from a variety of vendors, such as Xerium Technologies, Inc/Stowe Woodward (Youngsville, N.C.), Valley Roller Company, Inc. (Appleton, Wis.), American Roller Co. (Union Grove, Wis.).
In one embodiment, the base layer 12 radius, RBL, which describes the distance from the center of the converting roll 10 to the outer surface of the base layer 12, ranges from about 4 inches (10.16 cm) to about 12 inches (30.48 cm). In another embodiment, the base layer 12 radius is from about 5 inches (12.7 cm) to about 11 inches (27.54 cm). In another embodiment, the base layer 12 radius is from about 6 inches (15.24 cm) to about 10 inches (25.4 cm).
Without being limited by theory, it is thought that to provide effective pressure at the nip 50, the base layer 12 must provide adequate support against the elastomeric roll cover 16. In one embodiment, the hardness of the base layer 12 is from about 0.5 P&J to about 3.0 P&J. In another embodiment, the hardness of the base layer 12 is from about 1 P&J to about 2 P&J.
A paper web can comprise a plurality of plies where each ply is made of 55 percent northern softwood kraft, 30 percent Eucalyptus, and has a basis weight of approximately 13.5 pounds per 3000 square feet (21.97 gsm).
Only one ply is embossed in a rubber to steel embossing process. The emboss roll has emboss protrusions (embossment knobs) that are elliptically shaped having a major axis of 0.129 inches (3.28 mm), minor axis of 0.068 inches (1.73 mm), and height 0.070 inches (1.78 mm) (protrusion from the plane of the emboss roll). The conventional converting roll is constructed of a steel core about 110 inches (2.79 m) long with a radius of 6.0 inches (15.2 cm). An elastomeric rubber roll is disposed over the outer surface of the steel core. The elastomeric rubber roll is about 1.5 inches (3.81 cm) thick and has a hardness of about 100 P&J (±5 P&J).
The converting roll is aligned in an axially parallel configuration with the embossing roll. The paper web is passed through the nip, having a variable nip width of from about 1.5 inches (3.81 cm) to about 2.1 inches (15.33 cm) that forms between the rolls. The paper web is passed through the nip at a rate of about 1500 feet per minute (457 m/min).
The embossed paper web then has glue applied to the embossments that are formed on the surface of the paper web and is laminated. The embossments are then measured (as described in the “Embossment Structure Measurement Method” section below).
Returning again to
The emboss roll 30 has protrusions 70 (embossment knobs) that are elliptically shaped having a major axis of 0.129 inches (3.28 mm), minor axis of 0.068 inches (1.73 mm), and height 0.070 inches (1.78 mm) (from the plane of the surface of emboss roll 30). The converting roll 10 is constructed of a steel core about 110 inches (2.79 m) long with a radius of 6.25 inches (15.2 cm). An elastomeric roll cover 16 is disposed over the outer surface of the steel core 20. The elastomeric roll cover 16 is about 0.75 inches (1.91 mm) thick and has a hardness of about 105 P&J (±5 P&J).
Preferably, the converting roll 10 is aligned in an axially parallel configuration with the emboss roll 30. The paper web 40 is passed through the nip 50, having a variable nip 50 width of from about 1.5 inches (3.81 cm) to about 2.1 inches (5.33 cm) that forms between the respective emboss roll 30 and converting roll 10. The paper web 40 is passed through the nip at a rate of about 1500 feet per minute (457 m/min).
The embossed paper web 40 then preferably has glue applied to the embossments that are formed on the surface of the paper web 40 and is then subsequently laminated. The embossments are then measured (as described in the “Embossment Structure Measurement Method” section below).
The geometric characteristics of the embossment structure of the present invention are measured using an Optical 3D Measuring System MikroCAD compact for paper measurement instrument (the “GFM MikroCAD optical profiler instrument”) and ODSCAD Version 4.14 software available from GFMesstechnik GmbH, Warthestraβe E21, D14513 Teltow, Berlin, Germany. The GFM MikroCAD optical profiler instrument includes a compact optical measuring sensor based on digital micro-mirror projection, consisting of the following components:
The GFM MikroCAD optical profiler system measures the height of a sample using the digital micro-mirror pattern projection technique. The result of the analysis is a map of surface height (Z) versus XY displacement. The system should provide a field of view of 160×120 mm with an XY resolution of 21 μm. The height resolution is set to between 0.10 μm and 1.00 μm. The height range is 64,000 times the resolution. To measure a fibrous structure sample, the following steps are utilized:
It is noted that terms like “specifically,” “preferably,” “typically”, “generally”, and “often” are not utilized herein to limit the scope of the claimed invention or to imply that certain features are critical, essential, or even important to the structure or function of the claimed invention. Rather, these terms are merely intended to highlight alternative or additional features that may or may not be utilized in a particular embodiment of the present invention. It is also noted that terms like “substantially” and “about” are utilized herein to represent the inherent degree of uncertainty that may be attributed to any quantitative comparison, value, measurement, or other representation.
The dimensions and values disclosed herein are not to be understood as being strictly limited to the exact dimension or value recited. Instead, unless otherwise specified, each such dimension and/or value is intended to mean both the recited dimension and/or value and a functionally equivalent range surrounding that dimension and/or value. For example, a dimension disclosed as “40 mm” is intended to mean “about 40 mm”.
All documents cited in the Detailed Description of the Invention are, in relevant part, incorporated herein by reference; the citation of any document is not to be construed as an admission that it is prior art with respect to the present invention. To the extent that any meaning or definition of a term in this written document conflicts with any meaning or definition of the term in a document incorporated by reference, the meaning or definition assigned to the term in this written document shall govern.
While particular embodiments of the present invention have been illustrated and described, it would be obvious to those skilled in the art that various other changes and modifications can be made without departing from the spirit and scope of the invention. It is therefore intended to cover in the appended claims all such changes and modifications that are within the scope of this invention.
This application claims the benefit of U.S. Provisional Application No. 60/901,487 filed Feb. 15, 2007.
| Number | Date | Country | |
|---|---|---|---|
| 60901487 | Feb 2007 | US |
