MXPA99004273A - Tisu of paper that has a better softness - Google Patents

Abstract

A novel paper article, a method for making a paper product, and an engraving roll are described to provide a paper surface region having a minority of broken fiber-to-fiber bonds in the paper surface region at a time. depth of less than about 0.02 mm from the paper surface. In one aspect, the engraving roll that has been made but includes protuberances or depressions dimensioned to less than about 0. 1 mm. In one aspect, the engraving roll that has been made but includes protuberances or depressions adapted to produce the surface deformations of paper product on the paper surface, wherein the deformations of the paper product surface are invisible to a human eye without help. The present invention provides a paper product that has a superior perceived softness while maintaining a tensile strength.

Description

PAPER TISSUE THAT HAS AN IMPROVED SOFTNESS FIELD OF THE INVENTION 1. Field of the Invention The present invention relates to paper products. In one aspect, the invention relates to an etched paper product having improved softness. 2 ^ Background Attention should be given to a wide variety of product characteristics in order to provide a paper product that has the proper blend of characteristic suitable for the intended purposes of the product. Contributing to the wide variety of product characteristics is a rough arrangement of different tissue paper product forms, such as facial tissue, tissue for the toilet, sanitary napkins, and towels. Regardless of the form of the product, however, the improved softness of the paper product has been a main objective, especially with respect to the products of interest.

INTRODUCTION TO THE INVENTION The main components of the suavid include rigidity and volume. The lower rigidity and higher volume increase the perceived softness.

The engraving increases the volume or caliber of sheet. The superior volume can improve the perceived softness The engraving also provides an additional benefit by imparting a decorative pattern to the tissue product. U disadvantage associated with engraving is a reduction in the tensile strength of the product.

In addition to etching, the perceived softness of the product can be enhanced by (1) chemical aggregates, (2 calendering, (3) exchange supply, and (4) change creping. Like engraving, these methods also generate a concurrent decrease in resistance. to the traction of the product when they are used to increase the softness.

Therefore, in spite of the improvements in aesthetic appearance and volume gained from engraving, the additional improvements in softness would be beneficial for consumers. Processes and equipment are needed and a further improvement in the smoothness of the recorded paper products is needed in the art without an accompanying reduction in tensile strength.

This is an object of the present invention.

These and other objects of the invention will become more apparent from the reference to the figures and to the detailed description which follows.

SYNTHESIS OF THE INVENTION The present invention provides a method for making a paper product having a paper surface a surface region of paper treated by contact with a roughly etched roll to form a minority of fiber to fiber bond broken in the region of the paper. surface of the paper at a depth less than about 0.02 mm from the paper surface, the paper product has a mostly union kept essentially unbroken in an inner region at a depth of the paper surface of more than about 0.0 mm . In one aspect, the engraving roll includes protuberances or depressions dimensioned to less than about 0.1 mm. In one aspect, the rough engraving roll includes protrusions or depressions adapted to produce surface deformations of paper product on the paper surface, where deformations of the paper product surface are invisible to the human eye without assistance.

The present invention provides a novel etched roll having a rough surface in the form of dimensional protrusions or depressions for breaking a minority of the fiber to fiber bonds in a paper surface region of a paper product, wherein the protuberances or depressions are dimensioned to less than about 0.1 mm. The roughened embossing roll surface includes protuberances or depressions adapted to produce deformations on the surface of the paper product of said paper product, wherein deformations of the surface of the paper product are invisible to the human eye without assistance.

The present invention provides a paper product having a superior perceived softness while maintaining a tensile strength.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a schematic illustration of a process for texturizing paper products according to the present invention.

Figure 2 is a plan and perspective view of a part of an engraving roll used in the process shown in Figure 1.

Figure 3 is an enlarged sectional view taken along the plane of line 3-3 of Figure 2.

Figure 4 is a later amplified elevated view of the circle area shown in Figure 3.

Figure 5 shows a photomicrograph image a plan view of an engraving roll which has been laser engraved according to the present invention.

Figure 6 shows a photomicrograph image a plan view of an engraving roller which has been laser engraved of figure 5. / Figure 7 shows a photomicrograph image of an elevated view of an engraving roller engraved with lase of Figure 5.

Figure 8 shows a photomicrograph image of an elevation of an engraving roller which has been laser engraved of figure 5 on the interface between a male engraved element and a plain area.

Figure 9 shows a photomicrograph image of an elevation of a conventional steel engraving roller Figure 10 shows a photomicrograph image at a 45 degree top view of the conventional steel engraving roller of Figure 9.

Figure 11 shows a graphical display of tensile and crimped resistance values SPP (above) e against the height of the male engraving element for examples.

Figure 12 shows a graphical display of the SPP curl values (up and down) against the height of the male engraving element for the examples.

Figure 13 shows a graphical display of sandy SPP values (up and down) against the height of the male engraving element for the examples.

DETAILED DESCRIPTION The present invention provides a method for making a paper product having a paper surface a surface region of paper treated by contact with the etching roll made rough to form a minority of fiber-to-fiber bonds broken in the region of the paper. paper surface to a depth of less than about 0.02 mm from the paper surface. The paper product has a majority of joints maintained substantially unbroken in an inner region at a depth from the paper surface of plus d about 0.02 mm.

By fiber-to-fiber linkages it is meant that the bonds in a paper product formed by hydrogen bonds, for example, in a tissue of paper tissue, or the chemical bonds attributable to the straightening agents added to the fabric. By a minority of fiber to fibr linkages it is meant that about 5% to 20%, preferably about 10%, of the total bonds in a region of paper product. It has been found that at levels of less than about 5% of the broken joints in the surface region of the paper at a depth of less than about 0.02 m from the paper surface the preferred smoothing is not provided. At levels above about 20% of the joints broken in the surface region of the paper at a depth less than about 0.02 mm from the paper surface, the straightening begins to be adversely affected.

By a majority of fiber to fiber bonds it means about 50%, preferably about 90%, more preferably about 95% the total bonds in a region of paper product.

In one aspect, the rough embossing roll includes protrusions or depressions dimensioned to less about 0.1 mm. In one aspect, the coarse engraving roll includes protuberances or depressions adapted to produce deformations of the paper product surface of the paper surface, wherein the surface deformations of the paper product are invisible to a human eye without the aid. In one aspect, the paper product also includes decorative engraving. In one aspect, the roughly made engraving roll includes holes having a depth of less about 0.1 mm. The step of providing a paper product having a paper surface and a paper surface region treated by contacting a roughly etched roller to form a minority of the fiber to fiber bonds broken in the paper surface region at depth of less than about 0.02 mm from the paper surface forms a paper product having a higher perceived softening. In one aspect, the coarse engraving roll includes channels that have a depth of less than about 0.1 mm.

The present invention provides a novel etched roll having a surface that has become rough in the form of protrusions or depressions sized to break a minority of the fiber to fiber bonds in a surface region of the paper of a paper product, in where the protrusions or depressions are sized to less than about 0.1 mm. The surface of the rough engraving roll includes protuberances or depressions adapted to produce surface deformations of the paper product in the paper product, wherein the deformations of the surface of the paper product are invisible to the human eye without the aid. In one aspect, the roughened embossing roll surface includes protuberances or depressions formed by pickling or laser engraving of the engraving roll. In one aspect, the surface of the rough embossing roll includes protuberances or depressions formed by graining. In one aspect, the engraving roll contains visible engraving areas to form the visible paper engravings separated by plain areas containing protuberances or depressions to form invisible surface deformations in the paper product.

The present invention provides a paper product that includes a tissue of paper having a paper surface and a paper surface region treated by contacting an etching roller that has been roughened to form a minority of paper joints. fiber to fiber broken in the surface region of the paper to a depth of less than about 0.02 mm, the tissue of paper tissue has fiber-to-fiber bonding maintained essentially unbroken in an interior region at a depth from the surface of m paper of about 0.02 mm. In one aspect, tissue paper has a paper surface and a paper surface region treated by contacting a roughly made engraving roll which includes protrusions or depressions dimensioned to less than about 0.1 mm. In one aspect, tissue paper tissue has paper surface surface deformations that are invisible to the naked human eye formed by the protuberances or depressions of the engraved roller made rough. In one aspect, the tissue of pap tissue has a decorative engraving. In one aspect, the paper tissue has a paper surface and a paper surface region treated by contacting a roughly made recording roll which includes the pickled depressions or protuberances having a height or depth of less than about 0.1. mm. The paper surface region treated by contacting the roughly made engraving roller exhibits a superior perceived softness while maintaining essentially higher levels of tensile strength According to the methods and the apparatus of the present invention, an engraving roller with planar areas having a roughened surface and separating the male engraving elements is formed. The roughened surface includes either protuberances or holes of about 0.1 millimeters which work the surface fibers of a cellulosic fabric as it passes through a pressure point of engraving formed between the engraving roller and the backing roller. "Texturization" resulting from the fabric was found to improve softness. The engraving roll also includes a plurality of flanges or channels or both that similarly work the surface fibers.

According to the methods and the apparatus of the present invention, a tissue of paper tissue is passed through a gravure pressure point that includes a gravure roll having a roughened surface placed between the engraving elements. Specifically, in one embodiment, it forms an engraving roll with mac engraving elements separated by plain areas, and the plain areas have a roughened surface. The roughened surface includes the highlighted areas mentioned herein as protuberances includes depressions referred to herein as pits. When a paper product such as a toilet tissue is passed through an engraving pressure point formed between the roughly made engraved roller of the present invention and the backing roll, it has been found that the perceived softness is improved.

According to the methods and apparatus of the present invention, a perceived softness is benefited for the paper products processed by the methods and apparatus of the present invention.

The softness of a tissue product as perceived by a consumer is thought to be affected by four factors, which can be measured by trained sensory experts (Sensory Panel Participants or SPP). Attribute of a surface of a tissue that is indicative of softness of the tissue is mentioned herein as an attribute of curling the surface of the tissue. On the other hand, attributes of a tissue surface that are contraindicative of tissue softness are mentioned here as sandy and sandy surface attributes of tissue. Thickness is a fourth reflective attribute of perceived softness, with higher values perceived as being softer. The methods described herein have been found to increase the curl attribute of the engraved side of a tissue product without degrading the tensile strength of tissue. The increase in the ripple attribute is a result of paper product being "textured" in the planici areas between the engraving elements. More specifically, the paper product is "textured" in the sense that the surface fibers appear to be worked, flexed or displaced or a combination of worked, flexed or displaced by the roughened areas of the engraving roll.

In accordance with the methods and the apparatus of the present invention, working only the surface fibers breaks the bonds on the surface, improving the feeling, eg maintaining the lower joints intact, maintaining strength. Loosely bound surface fibers feel softer because they are able to flex more freely when touched. The "texturing" of the fabric between the engravings produces a tissue product with an improved softness.

The resistance to the main geometric tension (GMT) is the square root of the product of the tensile strength in the machine direction and the tensile strength in the cross-machine direction of the fabric. Unless indicated otherwise, the term "tensile strength" means a "geometrical principle tensile strength". The tensile strengths are measured using an Instron tensile tester using an inch jaw width, a 4 inch jaw extension, and a 10 inch per minute crosshead velocity after keeping the sample under TAPPI conditions. 4 hours before the test.

A wide range of shapes and sizes of the rough surface features are effective to lock the blade to produce additional softness.

According to the method and apparatus of the present invention it has been found that an important factor is the invisible nature of the fiber displacement resulting in which it gives a finished product appearance that is occupied and cleaner. The impact of rough terrain areas is not detectable by the human eye without help in the processed ti.

According to the method and apparatus of the present invention, it has been found that a second important fact is that only the layers of surface fibers in the sheet are worked so as to achieve an increase in surface smoothness (Curling) while the resistance is maintained. to geometric main traction (GMT) (flexibility) of the high t sheet as possible.

In an embodiment of the present invention, the engraving roller includes plain areas having a surface with holes. The pitted surface includes features, holes, cavities, scars, hollow hooks, dimples, depressions or the like. The surface features with holes have a diameter of about 0.0 to about 0.5 mm, preferably about 0.08 about 0.25 mm, for example about 0.1 mm. Hole surfaces are created by pickling l c? Orf.r.o.-nn T "maf" 1 corrosive such as acid, or it is created by mechanical treatment such as machining, graining, or engraving.

In another embodiment of the present invention, the engraving roller includes plain areas having a plurality of protuberances. The protuberances include features such as stops, flanges, embankments, hump hills, ripples, ridges, crowns or the like. The protrusions of the present invention have a height dimension compared to the secondary surface of the flat areas of about 0.01 to about 0.5 mm, preferably about 0.08 to about 0.25 mm, for example, about 0.1 mm. . The protuberances are created by pickling the surface of the reverse printing tool used to form the engraving roll by pickling the surface with corrosive material such as acid, or these are created by mechanical treatments such as walking, the engraving oe engraving.

In addition to the roughened surface or as an alternative thereto, the planar areas of the present invention include a plurality of ridges or channels or both. These ridges and channels are also relatively small, they work to work the surface fibers of the paper to improve the perceived softness. The ridges have a height dimension and the channels have a depth dimension d surface characteristics of about 0.01 to about 0.5 mm, preferably about 0.08 to about 0.2 mm, for example, about 0.1 rare, more preferably d about 0.1 millimeters (0.004 inches) or less preferably about 0.08 millimeters (0.003 inches) or less, such as about 0.05 millimeters (0.00 inches) or less. The ridges and channels have a width dimension of about 0.08 millimeters (0.00 inches) or less, preferably about 0.0 millimeters (0.002 inches) or less, such as about 0.025 millimeters (0.001 inches). The plurality of flanges and / or channels is suitably spaced one from another po about 0.08 to about 0.18 millimeters (0.003 - 0.00 inches).

The male engraving elements of the engraved roller d project upwards from the surrounding planic areas. The male engraving elements have a height dimension of about 0.05 inches (0.13 mm) more, such as from about 0.005 to about 0.07 inch (0.13 - 1.78 mm), and preferably from about 0.02 to about 0.04 inches (0.71 - 1.02 mm).

In particular embodiments it is preferred that the male engraving elements have a relatively low element height or to facilitate the contact of the tissue sheet with the plain areas in between the male engraved elements. For example, mach engraving elements preferably have a height dimension of about 0.005 inches (0.13 mm) to about 0.35 inches (0.9 mm) The benefits obtained from the harsh surface of the plain areas are independent of the engraved pattern created by the male engraving elements. Only the visible engraving patterns which are so compact as to avoid contact between the sheet surface and the flat areas of the engraving roll will be anticipated to exhibit no similar smoothness improvements. However, the degree of best correlates to the size of the open areas in the visible pattern and inversely correlates with the hardness of the rubber roll used at the engraving point.

A steel engraving roller is normally used for production situations, rather than the laser engraved ebonite roller used in the examples shown below. To increase the surface smoothness of a product of you while maintaining its tensile strength, you can A number of methods of roughing the surface are used while recording either the master tool or the final engraving rod. For maximum efficiency, these methods are best applied to the master tool so that identical codes on the finished roll result.

Suitable methods include the following any combination thereof: (1) Grane - individual points are hammered into the steel surface with small tools; (2) Machining - cutting or drilling or micropattern on the roller surface; (3) Free pickling - The pickling of uncontrolled acid was used to remove the softer areas of the steel at random; (4) Engraving that matches - a laser-grade ebonite rodill is used as a master recording tool to duplicate the random surface produced by the laser; and (5) Randomly engraved - a steel roller etched by a plasma arc or laser process.

In a preferred process of the present invention the desired (decorative) visible pattern is etched into an intermediate tool at a depth greater than the desired depth of the finished engraving roll. A second section of the tool is prepared by methods 1, 4, or 5 described above to produce the rough surface finish described herein, for example, as seen in the photomicrographs of the laser-engraved rodill described here below. Finally, a first intermediate tool was used to equalize the engraving of the decorative pattern on the second section of tool made rough at the desired depth of the finished engraving roll, thus not blurring the roughened surface of the second tool. From the first intermediate tool, a finished engraving roll is then engraved for commercial use.

The bath tissue rolls made according to the examples described below were subjected to a sensory panel evaluation. The sensory panel used trained individuals to compare the tissue products assessing the tactile properties against the standard products. The panelists were asked to render numerical values for each example tissue in relation to the following attributes: curly attribute for both sides of the tissue sandyness attribute for both sides of the tissue; attribute d Arenosity for both sides of the tissue; stiffness and stickiness For each example of bath tissue, the tissue samples were assorted from the rolls at 13.5 by 4.5 inches (3 strips of sheet 10 strips per stack). The ripple attribute was rated on a scale from 0, described as none / bald, to 7, described as much (ripple). Panelists were asked to consider the amount of fibers, hair, fiber, lint, and hair on the tissue surface. The panelists were instructed to place a single flat tissue sample on top of a smooth table with the side to be tested face up and using the tips of the index and middle fingers, to move the tissue mixture. unique in circular movements of a quarter size mu slightly through several areas of the sample.

The sandyness attribute was graded on a scale from 0, described as smooth, to 7 described, com m a- i The oanelists were asked to consider the amount of sharp, pointed, or abrasive fibers or particles 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 face up, with the forearm / elbow resting on the table, and using the full length of the fingers, to slide Gently lightly fingers across the entire surface an inch from the bord moving from left to right, use the other hand to rotate the tissue sample and stroke along all four directions, and evaluate the gritty direction.

The grainy attribute was rated on a scale from 0, described as smooth, to 7, described as grainy. Panelists were asked to consider the texture of pebbles from the tissue sample (grain sensation of sand, rice) and to evaluate by considering the frequency, size, and hardness / firmness / stiffness of the grains. S noted that the panelists' perception may include the form the orientation, and the size of the texture (pattern / engraving) of small rounded particles, and of fibers. The panelists were instructed to place a single tissue sample on a table with the side to be tested facing up, with the forearm / elbow resting on the table and using the pads of the index and middle fingers, Slowly and gently moving the fingertips across the surface and straight into the surface of the sample, one pulse from the edge moving from left to right, using the other hand to rotate the tissue sample and caress along all four directions and evaluate the grainy direction The rigidity was rated on a scale of 0, described as foldable / flexible, at 7, described as stiff rigid. Panelists were asked to consider the amount of edges or sharp, curled or cracked peaks felt from the sample while turning in the hand. The panelists were asked to place two (2) flat tis samples on top of a smooth table; the samples of bath tissue must overlap each other by 0.5 inches and are turned so that opposite sides of the tissue samples are represented during the test; with the forearm resting on the table, place the open palm down on the samples; place the hand of maner that the fingers are pointed toward the top of the samples approximately 1.5 inches from the edge; pull the fingers toward the palm with very little or no downward pressure to fold the tissue samples; and gently move the collected samples around in the palm of the hand for approximately 2 3 turns.

The thickness was graded on a scale of desd 0, described as thin, to 7, described as coarse. The panelists were asked to consider the relative depth of tis (perceived distance between the thumb and one / two fingers. The panelists were instructed to use a single piece of sample, to gently hold the tissue with the thumb between the index fingers. and second, with the other hand gently pull the tissue out of the retention, repeat this procedure several times on the bottom edge of the tissue to assess the degree of thickness as the fingers leave the edge of the tissue.

For the purposes given here, the term "paper is widely used to include writing, printing, wrapping, sanitary and industrial papers, periodic paper, lining cardboard, tissue, napkins, cleansers, towels In addition, "tissue tissue" or "tissue sheet" was used to refer to a suitable cellulosic fabric to make or use as a facial tissue, or tissue for toilet, paper towels, napkins or the like. Tissue tissue can be layered or non-layered, creped or non-creped and can consist of multiple layers or a single layer.In addition, the tissue can contain reinforcing fibers for integrity and strength. Use according to this invention is characterized as being relatively low-density, low density absorbers, particularly in terms of resistance to moisture.The densities are in the range d from about 0.1 to about 0.3 grams per cubic centimeter. The absorbency is about 5 grams of water per gram of fiber, and from about 5 to about 9 grams of water per gram of fiber, the tensile and wet strengths are around 0 to about 300 grams po inch wide and typically are at the lower end of this range, such as from about 0 to about 3 grams per inch. The dry stress strengths in the machine direction are from about 100 to about 2000 grams per inch in width, preferably from about 200 to about 350 grams per inch in width. The tensile strengths in the direction transverse to the machine are from about 50 to about 1000 grams per inch in width, preferably from about 10 to about 250 grams per inch in width. Dry weights are in the range of about 5 to about 6 pounds per 2880 square feet.

Many types of fiber are used for the present invention, including hardwood or soft woods, straw, linen, silk fibers of vendetósigo abacá seed, soft rushes, bagasse, cotton, hemp and cane and the like. Known paper fibers can be used including bleached and unbleached fibers, fibers of natural origin (including wood fibers and other cellulosic fibers), cellulose derivatives, and cross-linked or chemically stiffened fibers) or synthetic fibers (the synthetic fibers make up certain forms of fiber made of polypropylene, acrylic, aramid, similar acetates), virgin fibers and recovered or recycled, hardwood and softwood, and fibers that have been mechanically reduced to pulp (for example, groundwood), which have been reduced to pulp chemically (including but not limited to pulp reduction processes with sulfite and kraft), fiber that have been reduced to pulp thermomechanically, reduced to quimotermomecánicamente pulp and the like. Mixtures of any sub-set of the above mentioned kinds of fibers can be used. The fibers are prepared in a multiplicity of forms. Useful methods for preparing the fibers include dispersion to impart curl and improve drying properties.

Once formed, the tissue paper is processed using a wide variety of papermaking operations. For example, the paper web can be wet pressed, continuously dried, creped, non-creped or processed using a variety of other methods known in the art.

Numerous features and advantages of the present invention will appear from the following description and reference will be made to the accompanying drawings in which they illustrate the preferred embodiments of the invention. Tale additions do not represent the full scope of the invention. The reference should therefore be made to the claims given herein to interpret the full scope of the invention.

The invention will now be described in detail with reference to the figures, in which like elements and different figures have been given the same reference number. A paper product such as the fourth bath tissue 20 is textured using the process described in Figure 1 The tissue 20 is unwound from a tissue roll 22 and fed through an etching pressure point 24 formed between an engraving roller of etched steel 30 and a backing roller 32. The resulting textured tissue is rolled up and tissue rolls for bathroom on a furler 36. The rolls are cut subsequently to the appropriate widths the resulting individual tissue rolls are packed (n shown ). Although the invention is described in specific relation to bathroom tissue, the invention may be useful with a wide variety of paper products.

A plan view of a portion of the surface of an exemplary engraving roller 30, which is also referred to herein as the patterned roller, is shown in FIG. 2. The surface of the engraving roller 30 includes a plurality of engraving elements. discrete male 40 that is separated by relatively flat plain areas 42. Lo ol ama-nr-nc. The male fibers 40 are highlighted above the surface of the plain areas 42 and are pressed into the tissue 20 to form a corresponding image of the pattern d engraved when the tissue is processed through the engraved pressure point 24.

The engraving roller 30 is shown in a sectional view in Figure 3 to show various dimensions of a male engraving element 40. The male engraving elements 4 protrude from the plain areas 42 by a distance or height H, from around 0.005 inches (0.13 mm) or greater, for example such as from about 0.005 to about 0.07 inch (0.13 - 1.78 mm), and preferably from about 0.02 to about 0.04 inches (0.71 - 1.02 mm). The width of the male engraving elements at the tip is typically from about 0.005 to about 0.50 inches (0.127 - 12. mm). The side wall angle, theta (?), As measured in relation to the plane tangent to the roll surface at the base of the recording element, is from about 90 degrees around 130 degrees. The engraving roller 30 is formed by etching or other techniques described above.

Included in the illustrated engraving design, the male engraving elements 40 define a decorative pattern including a plurality of flowers 44 separated by intersecting play of dotted lines 46. Each flower 44 exhibited in Figure 2 includes a pattern of nine individual engraving elements. The groups with pattern can show flowers, leaves, birds, animals, waves, or any artistic concept.

Figure 4 shows an enlarged view of a plain area 42 from the area encircled in Figure 3, including in an embodiment of the present invention. Plain areas 42 of the engraving roller 30 preferably include a plurality of thin ridges 50 extending radially around the roller, or a plurality of fine channels 52 depressed in the steel roller and extending radially around the roller. The roller may include only the flanges 40, only the channels 52, or any other combination of the two. The ridges or channels contribute to the work of the surface fibers.

The ridges 50 have a height dimension. The channels 52 have a measured depth dimension from the surrounding surface of the plain area 42 of about 0.1 millimeter (0.004 inch) or less, preferably about 0.08 millimeter (0.003 inch) or less. , for example, such as about 0.05 millimeters (0.002 inches) or less. The width dimension of the flanges or channels or both, measured parallel to the axis of the roll is about 0.08 millimeters (0.003 inches) or less, preferably about 0.05 millimeters (0.002 inches) or less, for example, such as around 0.025 mm (0.001 inches). The ridges or channels or both are preferably spaced apart from each other by about 0.08 about 0.18 millimeters (0.003-0.007 inches).

Figures 5-8 show photomicrographic images of a laser stamped engraving roll according to the present invention. The photomicrographs of Figures 5-7 illustrate the roughened surface of the plain 42 areas. Plain areas include the surface features of protuberances and pits that work, flex or displace the surface fibers of the fabric 20 when the surface is processed. tissue 20 through the engraving pressure point 24.

The photomicrograph of Fig. 8 shows the same roller as Figs. 5-8, but on a ridge between a male engraving element 40 and a plain area 42. Because the roughened surface of this particular roller is formed by laser marking, the surface that has been made rough covers the sides of the male engraved elements as well as the areas of plains.

For comparison purposes, Figures 9 and 10 show photomicrographic images of a conventional steel engraving roll. Conventional steel engraving rollers have a surface finish with imperfections on the order of 0.005 mm or smaller and height and about 0.001 mm in width, which takes the form of random ridges in a roughly honeycomb as shown by photomicrographs.

The backing roller 32 includes a roller covered with smooth rubber, an engraved roller such as the steel roller and matched to the pattern roller or the like. The point of attachment pressure d is set for a backing / patterned roll load pressure of from about 30 to about 30 pounds per linear inch (pli), and more preferably from about 50 to about 150 pounds. per linear inch, for example, so that the engraving pattern is imparted to the tissue 10. The backing roll is a material that fills the process requirements such as natural rubber, synthetic hul, or other compressible surfaces, and has a Shore A surface hardness of about 20 durometers or more preferably 40 durometers or greater, for example, such as about 75 durometers. Preferably, the back roll d includes a conformable and elastic material.

EXAMPLES The following examples are provided to give a more detailed understanding of the invention. The amounts of particulars, proportions, compositions, and parameter are intended to be exemplary and are not intended to specifically limit the scope of the invention.

These examples were the result of a large designed experiment using one of the three base sheets designated Paper Codes A, B and C. The base sheets have base weights that differ, but otherwise have essentially similar properties. Each base sheet was composed of sulfite pulp containing one third of soft northwood and two thirds of northern hardwood. The Paper Code was 16.5 pounds per 2880 square feet completely dry, and Paper Code B was 15.9 pounds per 2880 square feet completely dry; and Paper C Code was at 15.2 pounds per 2880 square feet completely dry. The caliber of leaf 10 varied from 0.072 to 0.077 inches (1,829 to 1,956 mm), and the resistance to the Main Geometric Traction (GMT) varied from 650 to 800 per g / three-inch strip. The bas leaves were cut into narrow rolls for conversion.

In each example, the base sheet was processed through a pilot scale conversion line operating 1000 feet per minute. As the single stratum, the bas leaves were unwound from two web-unrolled supports. The two strata were folded together using an S-wrap married roller and a recollection unit. The two-layer weave was then etched using a small steel rubber roller engraving device, replacing the steel roller with laser engraving ebonite in the pilot scale tests. The engraving roller included a textured or roughened surface between the engraving elements as shown in Figures 2-4. The bas leaf was then rewound into the rolls and individual toilet tissue rolls were cut using a coil saw.

The engraving roll used in the examples was an ebonite roll having an engraving pattern shown in Figure 2. In addition, the ebonite roll was engraved with laser at 500 dots per inch (dpi) which left a finished surface rough. The engraving process resulted in the areas of the roller plain having multiple imperfections on the order of 0.1 mm in all three axes, with some imperfections being larger and some being smaller in an altered occurrence (see the photomicrographs of the figures). 5-8). In combination with these imperfections, the plain areas of the laser engraved rolls also included some channels of the type illustrated in Figure 4.

The elastic backing rolls used in the examples were formed of a combined rubber material known under the name of HYPALON in commerce. The elastic backing rolls were of a Shore A hardness of 73 or 75 durometers.

EXAMPLE 1 The tissue rolls for bathroom designated Roll Code 6 were formed from the heavier weight tissue, e Paper Code A, using the conversion process described above. The engraving roller included an engraving pattern of 0.040 inches deep, and the elastic backing roller had an outer shell with a Shore A hardness of 7 durometers. The engraving pressure point was set at 103 pounds per linear inch (pli). The resulting roll diameter was 4.6 inches.

Example 1 represented the engraving conditions for the height of the element, the hardness of the backing roll of the pressure point pressures used for the two-layer bath tissue. The tensile strength of the tissue was 671.4 grams per 3 inches. The tissue samples of Example 1 were prepared for a sensory evaluation and resulted in a SPP ripple value of 5.08.

EXAMPLE IB Example IB was similar to Example 1 except that Paper Code B was used. The tensile strength of the tissue was 598.3 grams per 3 inches, and the SPP curled value was 4.92.

EXAMPLE IC Example 1C was similar to Example 1 except that Paper Code C was used. The tensile strength of the tissue was 543.3 grams per 3 inches, and the curl value SPP was 5.23.

EXAMPLE 2 The bath tissue rolls designated Code d Roll 21 were formed from Paper Code A, using the conversion process described above. The engraving roller included an engraving pattern of 0.034 inches deep, and the elastic backing roller had an outer shell with a Shore A hardness of 75 durometers. The engraving pressure point was set to 117 pounds per linear inch. The resulting roll diameter was 4.6 inches.

Example 2 employed a slightly higher clamping point pressure and a shallower engraving pattern depth which places the tissue sheet closer to rough area between the male engraving elements. The tensile strength of the tissue was 612. grams per 3 inches. The tissue samples of Example 2 s were prepared for a sensory evaluation and resulted in an SPP ripple value of 5.09.

EXAMPLE 2B Example 2B was similar to Example 2 except that Paper Code B was used, and the clamping point pressure was 135 pounds per linear inch. The tensile strength of the tissue was 540.5 grams per 3 inches, and the SPP curled value was 5.05.

EXAMPLE 2C Example 2C was similar to Example 2 except that Paper Code C was used. The tensile strength of the tissue was 603.5 grams per 3 inches, and the SPP curled value was 5.07.

EXAMPLE 3 The bath tissue rolls designated Roll Code 16 of Paper Code A were formed, using the conversion process described above. The engraving roller included an engraving pattern of 0.034 inches deep, and the elastic backing roller had an outer shell with a Shore A hardness of 75 durometers. The engraving pressure point was set at 129 pounds per linear inch. The resulting roll diameter was 4.9 inches.

Example 3 used increased the engraving pressure to force the tissue sheet to deform it sufficiently to benefit significantly from the roughened area between the male engraving elements. The tensile strength of tissue was 605.0 grams per 3 inches. The tis samples of Example 3 were prepared for a sensory evaluation resulting in a SPP ripple value of 5.35.

EXAMPLE 3B Example 3B was similar to Example 3 except that Paper Code B was used, and the clamping point pressure was 135 pounds per linear inch. The tensile strength of the tissue was 605.3 grams per 3 inches, and the SPP curled value was 5.11.

EXAMPLE 4 The bath tissue rolls designated Roll Code 22 of Paper Code A were formed, using the conversion process described above. The engraving roller included an engraving pattern of 0.028 inches deep, and the elastic backing roller had an outer shell with a Shore A hardness of 63 durometers. The engraving attachment point was set at 94 pounds per linear inch. The resulting roller diameter was 4.6 pulses.

Example 4 represents a preferred embodiment of the present invention in the sense that the softer backing roll forces the tissue sheet to deform sufficiently to benefit significantly from area that has become rough between the male engraving elements even though it was run with a reduced engraving pressure. The tensile strength of the tissue was 620.7 grams per inch. The tissue samples of Example 4 were prepared by the sensory evaluation and resulted in a SPP rip value of 5.43.

EXAMPLE 4B Example 4B was similar to Example 4 except that the Paper Code B was used, and the pressure of the fastening point was 64 pounds per linear inch. The tensile strength of the tissue was 560.3 grams per 3 inches, and the SPP ripple value was 5.48.

EXAMPLE 4C Example 4C was similar to Example 4B except that the Paper Code C was used. The tensile strength of the tissue was 571.6 grams per 3 inches, and the SPP curled value was 5.38.

EXAMPLE 5 The bath tissue rolls designated Roll Code 27 were formed from Paper Code A, using the conversion process described above. The engraving roller included an engraving pattern of 0.028 inches deep, and the elastic backing roller had an outer shell with a Shore A hardness of 63 durometers. The etching point s put at 96 pounds per linear inch. The resulting roll diameter was 4.9 inches.

Example 5 represents another preferred embodiment of the present invention similar to that of Example 4 even when the sheet is not rolled under as much tension as rolls of diameter 4.6 inches. The tensile strength of the tissue was 632.1 grams per 3 inches. The tissue samples of Example 5 were prepared for a sensory evaluation and resulted in a SPP ripple value of 5.54.

EXAMPLE 5B Example 5B was similar to Example 5 except that the Paper Code B was used, and the pressure at the point of attachment was 75 pounds per linear inch. The tensile strength of the tissue was 538.8 grams per 3 inches, and the SPP ripple value was 5.41.

EXAMPLE 6 Example 6 was similar to Example 1 except that the pressure of the clamping point was 98 pounds per linear inch, and the diameter of the roll was 4.9 inches. The tensile strength of the tissue was 618.0 grams per inch, and the value of rippled SPP was 5.22.

EXAMPLE 6B Example 6B was similar to Example 6 except that the Paper Code B was used, and the pressure of the fastening point was 123 pounds per linear inch. The tensile strength of the tissue was 626.9 grams per 3 inches, and the SPP ripple value was 4.95.

Table 1 given below summarizes the data of the examples. In the table the "Roller Drill" refers to the elastic rubber backing roller durometer measured in Shore A hardness. The "Nip Prs." Refers to the pressure of the engraving clamping point, and "Dia. Rollo "refers to the diametr of tissue roll for finished bathroom.

TABLE 1 All the SPP data in this study has been scattered within groups due to other variables in the experimental design. The GMT localized variability for the manufacture of tissue up to 10% was considered acceptable. Relevant variables included the differences in the base sheet, the changing engraving pressure point load, the changing rubber roller durometer, and the finished roll diameter from 4.6 inches to 49 inches. The data progressions for Paper Codes B and C were found to be similar to those of Paper Code A.

With reference to Figure 11, the upward SPP curd rating showed a reasonable correlation with the engraving pattern depth but this effect was not linked to a commensurate decrease in the GMT as would normally have been expected according to a resistance ratio. smoothness. This result was attributable to the blade making contact with the rough end of the laser sleeve between the male engraving elements and the breaking of some of the hydrogen bonds between the fibers, thereby freeing one end of the fiber pair projecting out towards the user . Even when there were no visible eye marks, when the back areas of the recorded sheet were examined, the SPP data indicated the beneficial effect of this texturizing action, and an analytical "ripple and edge" technique showed that Example 4 it was 1.33 times tared as in Example 1.

These results were corroborated by the downward rating of curly SPP which is done on the side of the sheet that is not in contact with the patterned master roll. With additional reference to Figure 12, the curled down ratings on these codes exhibited the increase in qualification with decreases in the height of items that were apparent with the ratings recorded upward. The "top" side of the tissue was in contact with the engraving roller that had been etched with laser. The surface of the roller that became rough with lasse worked some of the fibers and released them on the surface of the sheet, thus increasing the rating of the ripple of the one above.

The above and below ratings of sandstone SPP also showed a beneficial impact as the height of the engraving element was reduced as shown with reference to figur 13. This impact is attributable to an increased calender effect when the height of the element was reduced, since the fall in the trend line of qualification of above arenos was parallel by means of a fall in the trend line d rating of sandy down. Such a parallel result between the sides of a two-layer tissue sheet applied to both the gritty and curly l, and highlighted the present invention described herein when the curled lines did not exhibit the expected trend.

Even though the selection of an engraving element height to be used in a particular application depends on a number of product and equipment form constraints, examples show that a beneficial example was achieved when using the engraving roll surface made Rough of the present invention, particularly when combined with the select a lower male engraving element height.

Even when the current examples are concentrated on rubber-to-steel engraving, a similar result is produced in an extension in a properly prepared set of steel or paper-on-steel engraving rolls matched. The production of such an effect will depend on the penetration (distance from the bottom) to which the engraving rolls are run.

The results obtained from the rubber roll of 6 durometers better incorporated the desired inventive step, but the results of the roll of 73 durometers showed a similar response even when it falls lower in the same direction. The use of alternative roll compositions or alternative durometer rubber rollers (either higher or lower) will achieve the exact level of texturing desired.

The above detailed description has been given for the purposes of illustration. Therefore, a number of modifications and changes can be made without departing from the spirit and scope of the present invention. For example, the alternative or optional features described as part of a modality are used to give another modality.

Additionally, two named components can represent parts of the same structure. In addition, several alternate processes and equipment arrangements can be employed. Therefore, the invention should not be limited by the specific embodiments described but only by the claims and all equivalents thereof.

Claims (20)

R E I V I N D I C A C I O N S

1. A method to make a paper product which comprises: providing a paper product having a paper surface and a paper surface region treated by contacting an etching roll that has been roughened to form a minority of broken fiber-to-fiber bonds in said paper surface region at a depth less than about 0.02 mm from the paper surface, said paper product has a majority of joints maintained essentially unbroken in an inner region at a depth from said paper surface of more than about 0.02 mm.

2. A method for making a paper product as claimed in clause 1, characterized in that said rough engraving roll comprises protuberances or depressions dimensioned to less than about 0.1 mm.

3. A method for making a paper product as claimed in clause 1, characterized in that said rough engraving roll comprises protuberances or depressions adapted to produce deformations of paper product surface on said paper surface, wherein the deformations from the surface of the paper product s invisible to a human eye without help.

4. A method for making a paper product t and as claimed in clause 1, characterized in that the paper product also comprises a decorative engraving.

5. A method for making a paper product t and as claimed in clause 1, characterized in that the engraving roll that has been roughened comprises pits q having a depth of less than about 0.1 mm.

6. A method for making a paper product and as claimed in clause 1, characterized in that the step of providing a paper product having a paper surface and a paper surface region is treated by contact with an engraving roller that It has been roughened to form a minority of fiber to fiber bonds broken in said paper surface region at a depth of less than about 0.02 mm from the paper surface form or paper product having a higher perceived softness.

7. A method for making a paper product ta and as claimed in clause 1, characterized in that said engraving roll which has been made rough comprises channels having a depth of less than about 0.1 mm.

8. An engraving roller for treating a paper product, comprising: an engraving roll having a surface which has become rough in the form of protrusions or depressions sized to break a minority of the fiber fiber joints in a paper surface region of a paper product, wherein said protuberances or depressions it is sized to less than about 0.1 mm.

9. An engraving roll for treating a paper product as claimed in clause 8, characterized in that said roughened surface comprises protuberances or depressions adapted to produce product surface deformations in said paper product, wherein Deformations of the surface of the paper product are invisible to the human eye without help.

10. An engraving roll for treating a paper product as claimed in clause 8, characterized in that said roughened surface comprises protuberances or depressions formed by the etched etching of the engraving roller.

11. An engraving roll for treating an Oaoel product as claimed in clause 8, characterized in that said roughened surface comprises protrusions or depressions formed by graining.

12. An engraving roll for treating a paper product as claimed in clause 10 characterized in that said engraving roll contains visible engraving areas to form visible paper engravings separated by flat areas containing said depressions protuberances to form deformations of invisible surface in the paper product.

13. An engraving roll for treating a paper product as claimed in clause 11 characterized by said engraving roll contains visible engraving areas to form visible paper engravings separated by flat areas containing said depressions protuberances to form deformations of invisible surface in the paper product.

14. A paper product, comprising: a tissue of paper having a paper surface and a surface region of paper treated by contacting an etching roll that has been roughened to form a minority of fiber to fiber joints broken in said surface region of Paper at a depth of less than about 0.02 mm, said tissue of paper having fiber-to-fiber joints maintained essentially unbroken in an interior region at a depth from said paper surface of more than about 0.02 mm.

15. A paper product as claimed in clause 14, characterized in that the engraving roll which has been made rough comprises protuberances or depressions dimensioned to less than about 0.1 mm.

16. A paper product as claimed in clause 14, characterized in that said paper product comprises surface deformations of paper product which are invisible to the unaided human eye formed by the engraving roll depressions or protuberances that have been made rough.

17. A paper product as claimed in clause 14, characterized in that said paper product further comprises decorative engraving.

18. A paper product as claimed in clause 16, characterized in that said engraving roll which has been made rough comprises pickled protuberances or depressions having a depth height of less than about 0. 1 mm.

19. A paper product as claimed in clause 14, characterized in that said tissue of paper tissue having a surface region of paper treated by contacting said engraving roll which has been roughened exhibits a superior perceived softness while which maintains essentially similar levels of tensile strength.

20. A paper product as claimed in clause 14, characterized in that said engraving roll which has been made rough comprises channels having a depth of less than about 0.1 mm. R E S U E N A novel paper article, a method for making a paper product, and a recording roll are described to provide a paper surface region having a minority of broken fiber-to-fiber bonds in the paper surface region to a depth of less than about 0.02 mm from the paper surface. In one aspect, the engraving rod that has been made rough includes depressed depressions dimensioned to less than about 0.1 mm. In appearance, the roughly engraved engraving roll includes protrusions or depressions adapted to produce the deformations of paper product surface on the paper surface, where the deformations of the paper product surface are invisible to one eye human without help. The present invention provides a paper product having a superior perceived softening while maintaining a tensile strength.