MXPA99009616A - High pressure embossing and paper produced thereby - Google Patents

Abstract

A process for high pressure embossing a single ply of paper and the paper produced thereby. The embossing process requires two rolls, a pattern roll (30) and an anvil roll (32). The rolls are loaded together at a pressure of at least 1000 psi at the nip. A single ply of paper is embossed in the nip. The embossments of the paper do not extend outwardly beyond the thickness of the paper to have any out-of-plane deformation. The embossments are typically glassined. The resulting paper has an aesthetically pleasing appearance, without undue loss of tensile strength from the embossing process.

Description

HIGH PRESSURE AND PAPER PRODUCED BY HIMSELF FIELD OF THE INVENTION The present invention relates to the embossing of paper and particularly to the decorative embossing of a single sheet of tissue paper.

BACKGROUND OF THE INVENTION Embossing is well known in the art field. Embossing is a common technique used to join two sheets of paper and form a multi-laminate laminate. The resulting laminate has properties, such as caliper, flexibility and absorbency, which are not achieved from a single sheet having twice the base weight of each constituent sheet. The prior art shows the embossing of two sheets of paper together. The embossing is carried out by one of the various known embossing processes, such as embossment to protuberance or lamination of double sheet. The aforementioned processes are illustrated in co-assigned US Patents 3,414,459 issued December 3, 1968 to Wells and 5,294,475 issued March 15, 1994 to McNeil, whose exposures are considered to form part of this, as a reference . Still another embossing process for joining two sheets is the nested embossing, which "is well known in the art." With each of the aforementioned embossing processes, the embossments are deflected away from the plane of the paper.That deflection or deflection can increase Conveniently the size of the sheet and, therefore, the laminate, conventional embossing can increase the size between 25 and 135 percent as the embossing pressures deform the fibers out of the plane of the paper. paper means that the reliefs extend outside the original thickness of the paper without embossing.Thus, the reliefs that are deformed out of the plane of the paper extend outwards from the surface of the paper thereby increasing its caliber. of the embossing pattern is directly proportional to the magnitude of the out-of-plane deformation of these reliefs There is an associated loss in the resistance to tension caused by the reliefs out of plane. A common drying substrate by air passage, such as that found in CHARMIN bath paper marketed by The Procter & The Gamble Company of Cincinnati, Ohio, has experienced a loss of tension of between 20 and 40 percent during conventional embossing processes.

In addition, the prior embossing technique often degrades softness. It is believed that the degradation of softness is due to the tactile sensation caused by the out-of-plane reliefs. The embossing processes typical of the prior art depend on a conventional rubber anvil roll and a steel pattern roll to form the aesthetic pattern. The aesthetic pattern is derived from the deformation of the fibers out of plane of the paper when the sheets are etched against the deformable anvil roll. An attempt of the prior art to etch an aesthetic pattern on paper is illustrated in U.S. Patent 5,436,057 issued July 25, 1995 to Schulz. As illustrated in Figures 13-14 of Schulz '057, this attempt requires embossing the paper out of its plane to form the reliefs. A similar attempt in the art is illustrated in European Patent Application 0 668 152 Al published on August 23, 1995, in the name of Kamps et al. Kamps et al also suffers from the drawback, illustrated in Figure 10, that the sheets are embossed out of the plane of the paper. Neither Schulz '057 nor Kamps et al. they suggest the embossing of an aesthetic pattern within the plane of the paper. Other attempts in the art have used relatively high embossing pressures. However, such attempts are limited to joining several sheets of paper together. For example, U.S. Patent 3,377,224 issued on April 9, 1968 to Gresham et al. shows the embossing of two sheets of paper creped differently at the same time without adhesive. The process requires protrusions of 1/32 of an inch square. A similar attempt is found in the United States Patent 3, 323,983 granted on June 6, 1967 to Palmer et al. Palmer et al. shows an embossing process that fixes sheets of thin creped paper at the same time. NI Gresham and Palmer et al. they suggest the embossing of a simple sheet of paper. Instead of this, each teaching limits the embossing process to join two or more sheets of paper together. The European Patent Application assigned jointly WO 95/27429 filed on April 12, 1995 in the name of Reinheimer et al. shows a cellulose fabric comprising at least two layers. The layers are joined with an engraved pattern of individual impressions in the shape of polka dots that deform and interconnect the fabrics of the fabric. The impressions are formed by embossed polka dots that originate from the outer layers of the fabric and curve into a concave inward shape. In contrast, embossing according to the present invention uses only a single sheet of paper. He P892 aesthetic pattern that results from embossing the simple sheet is within the plane of the paper. In addition, embossing according to the present invention decreases the loss of associated tensile strength. The loss of the tensile strength associated with the embossing according to the present invention is usually less than percent and in some cases less than 5 percent. In addition, the present invention decouples the clarity of the pattern and the magnitude of the out-of-plane deformation of the reliefs. In the present invention, the clarity of the pattern is not determined by the depth of the reliefs. Instead, the clarity of the pattern is determined by the reflective nature of the reliefs. In particular, the reliefs are often "glasinados" and are more reflective than the non-embossed regions of the paper. The embossing according to the present invention increases the modulus of the paper. The module in grams per centimeter is the slope of the stress-strain curve of the paper as it is loaded into a tensile test apparatus at a restriction elongation speed of one inch per minute, using a test length of two. inches and a sample width of four inches. The slope is measured at a load of 15 grams per centimeter of sample width.

P892 Accordingly, it is an object of the present invention to provide an embossed paper having no out-of-plane reliefs. It is also an object of the present invention to provide an embossed paper that does not experience excessive loss of tensile strength as a consequence of the embossing process. It is another object of the invention to provide a simple sheet of paper having an embossing pattern that is visually distinguished. Finally, it is an object of the invention to decouple the clarity of the engraved pattern from the relief background.

SUMMARY OF THE INVENTION The invention comprises a simple sheet of paper having two sides, a first side and a second side opposite each other. The first and second sides of the paper are separated by the thickness thereof. The paper is embossed to have reliefs. The reliefs extend inward from the first side of the paper, to the second and opposite side of the paper. The reliefs do not extend out from each side of the paper. The paper may also have reliefs extending inward from the second side of the paper. If the paper is provided with reliefs that extend inwards from the second side, those reliefs, of the same P892 mode, they do not extend out of the paper. The embossings on the second side of the paper may be in register with the reliefs on the first side of the paper or may be offset therefrom. Preferably, the reliefs comprise "glasinated" regions on the paper. The "glasinated" regions have an increased reflectivity in general and provide an aesthetic advantage. Preferably, the surface topography of the non-embossed regions of the paper is relatively fine compared to the size of the reliefs, so that aesthetic clarity is maintained.

BRIEF DESCRIPTION OF THE DRAWINGS OR FIGURES Figure 1 is a side elevational view of a gingiva device according to the present invention. Figure 2 is an enlarged fragmentary view of Figure 1, illustrating reliefs that remain within the plane of the paper. Figure 3 is a schematic side elevational view of a paper embossing apparatus according to the prior art. Figure 4 is an enlarged fragmentary view of Figure 3, illustrating the reliefs out of the plane that are not within the plane of the paper. Figure 5 is a top plan view of an embossing pattern having four sizes of repeating units and showing the largest repeating unit centered on the nip or contact point.

DETAILED DESCRIPTION OF THE INVENTION With reference to Figures 1 and 2, the present invention comprises paper 10 and more particularly a simple sheet of paper 10. The single sheet of paper 10 has two opposite sides, a first side 12 and a second side 14. The paper 10 has a thickness T defined by the distance between the first and second opposite sides 12, 14. The paper 10 according to the present invention is usually described and is useful for facial tissues, toilet paper, paper towels, napkins, wet towels, handkerchiefs and a variety of related uses. Someone with ordinary experience will be able to adapt the paper 10 of the present invention to the desired use. The plane of the paper 10 defines its dimensions X-Y. The direction Z of the paper 10 is perpendicular to the dimensions X-Y of the paper 10 and to the plane of the paper 10. The thickness T of the paper 10 is measured in the Z direction.

The paper 10 also has embossments 20. The embossments 20 refer to the regions in the paper 10 that have been densified or otherwise compacted. The fibers comprising the paper 10 in the reliefs 20 are preferably permanently and more closely joined than the fibers in the regions of the paper 10 intermediate to the reliefs 20. The reliefs 20 can be "glasinados". Preferably the reliefs 20 are different from each other, although if desired, the reliefs 20 can form a basically continuous network. In contrast to the embossing process of the prior art illustrated in Figures 3 and 4, the embossments 20 of the present invention do not extend outwardly beyond the plane defined by the two opposite sides of the paper 10. The embossments 20 extend inward either from the first side 12 of the paper 10, the second side 14 of the paper 10 or from both sides, as illustrated in Figures 1 and 2. If the embossments 20 extend inward from both sides 12, 14 of the paper 10, the embossments 20 on one side 12 may be in register with the reliefs 20 extending inwardly from the opposite side 14 of the paper 10 or may be offset therefrom. It is admitted that two simple sheets of paper 10, of which one or both are made according to the present invention, can be put together in a face-to-face relationship, to form a laminate. Such joining and use of a plurality of single sheets of paper 10 according to the present invention does not take paper 10 out of the scope of the appended claims. The substrate comprising the paper 10 according to the present invention can be dried in a conventional manner, using one or more press felts. If the substrate comprising the paper 10 according to the present invention is dried in a conventional manner, it may be conventionally dried using a felt which applies a pattern to the paper 10 as shown in co-assigned United States Patent 5,556,509 issued on September 17, 1996 to Trokhan et al. and PCT Application WO 96/00812 published January 11, 1996 in the name of Trokhan et al., whose exposures are considered hereby incorporated by reference. Preferably, the substrate comprising the paper 10 according to the present invention is dried by air passage. A suitable air dried drying substrate may be made according to co-assigned U.S. Patent 4,191,609, the disclosure of which is hereby incorporated by reference. More preferably, the substrate comprising the paper 10 according to the present invention is dried by passing air over a band having a patterned structure. The structure preferentially prints a pattern comprising a substantially continuous web on paper 10 and further has deflection conduits dispersed within the pattern. The deflection conduits extend between the first and second opposing surfaces of the structure. The deflection conduits allow domes to be formed in the paper 10 according to the present invention. The band according to the present invention can be made according to any of the United States patents assigned jointly 4,637,859 granted on January 20, 1987 to Trokhan; 4,514,345 issued April 30, 1985 to Johnson et al .; 5,328,565 issued on July 12, 1994 to Rasen et al .; and 5,334,289 issued on August 2, 1994 to TrokLhan et al., whose exhibits are considered part of the present by reference. The air dried paper 10 produced according to the aforementioned patents has a plurality of domes dispersed throughout an essentially continuous network region. The domes extend generally perpendicular to the paper 10 and increase their caliber. The domes in general correspond in geometry and during the elaboration of the paper in position, to the deflection conduits of the band described above. The domes project outside the basically continuous network of paper 10 P892 because they are molded into the deflection ducts during the papermaking process. By molding in the deflection conduits during the papermaking process, the regions of the paper 10 comprising the domes deviate in the Z direction. For the embodiments described herein, a paper 10 can have at least 300 domes per square inch, although this figure depends on the size of the embossments 20. Preferably, if the paper 10 has domes or other prominent features in the topography, each relief 20 in the paper 10 has an area at least 10 times and more preferably at least 100 times larger than the area of the dome or another prominent feature in the topography. If a paper 10 having such domes is selected for the present invention, the domes may extend outwardly from a first side 12 of the paper 10 and the embossments 20 extend inward from each side of the paper 10. However, preferably, the embossments 20 extend inwardly from the second side 14 of the paper 10. The paper 10 according to the present invention and having domes can be made according to commonly assigned U.S. Patents 4,528,239 issued July 9, 1985 to Trokhan; 4,529,480 granted on 16 P892 July 1985 to Trokhan; 5,245,025 granted on September 14, 1993 to Trokhan et al .; 5,275,700 granted on January 4, 1994 to Trokhan; 5,364,504 issued November 15, 1985 to Smurkoski et al. and 5,527,428 issued on June 18, 1996 to Trokhan et al., whose exhibits are considered part of the present by reference. Some variations in the substrate used for the paper 10 according to the present invention are feasible and may be convenient depending on the application. The substrate comprising the paper 10 according to the present invention may be creped or uncreped, as desired. The paper 10 according to the present invention may be layered. Layering is disclosed in co-assigned US Patents 3,994,771, issued November 30, 1976 to Morgan et al .; 4,225,382 issued September 30, 1980 to Kearney et al .; and 4,300,981 granted on November 17, 1981 to Carstens, whose exhibitions are considered part of this as a reference. To further increase the soft tactile feel of the paper 10, chemical softeners may be added to the paper 10. Suitable chemical softeners may be added as shown in co-assigned United States Patents 5,217,576 issued June 8, 1993 to Phan and 5,262,007 granted on November 16, 1993 P892 to Phan et al., Whose exhibitions are considered part of the present as reference. In addition, silicone can be applied to paper 10 according to the present invention as shown in co-assigned United States Patents 5,215,626 issued June 1, 1993 to Ampuiski et al. and 5,389,204 granted on February 14, 1995 to Ampuiski, whose exhibitions are considered part of the present as reference. The paper 10 may be moistened, as set forth in co-assigned U.S. Patent 5,332,118 issued July 26, 1994 to Muckenfuhs, the disclosure of which is hereby incorporated by reference. Returning to Figure 2, embossing according to the present invention can be carried out using two axially parallel, cylindrical rollers 30, 32 juxtaposed to form a point of contact between them The first roller is a pattern roller 30 and has protuberances 34 which they extend radially outward from the periphery of the roller 30. The second roller is an anvil roll 32 and has a surface that is smooth to the naked eye, preferably the anvil roll 32 has a machined surface with a finish of 32 micro-inches per inch or Neither the pattern roller 30 nor the anvil roller 32 P892 are deformed during the embossing process according to the present invention. While in theory some deformations can be predicted in response to an applied load, the pattern rolls and anvil 32, 32 are sufficiently non-deformable and rigid to prevent deformation that allows the reliefs 20 to be formed out of the plane in the paper 10. Anvil roller 32 can be a crown roller. Each of the rollers 30, 32 is preferably made of steel and more preferably hardened, although any relatively non-deformable rigid material can be used. If the rollers 30, 32 are made of steel, each roller 30, 32 must have a Rockwell C hardness of 20-25. Preferably, for a maximum life, the rollers 30, 32 have a Rockwell C hardness of at least 50 and more preferably a Rockwell C hardness of at least 58. A rubber anvil roll 32, as illustrated in FIG. Figure 4 and which is known in the prior art, generally should not be used. Prophetically, in a less preferred embodiment, for some applications, a very hard rubber roll may be suitable, for example a rubber roll having a hardness less than 10 P &J, determined with a 1/8 inch ball. diameter . Without taking into account the materials used in P892 construction, the anvil roll 32 must not deform during the embossing process. If deformation occurs in the anvil roll 32, reliefs will be formed out of plane in the paper 10 and a loss of tensile strength will result. One of the two or both the anvil roller 32 and the master roller 30 can be heated internally. Prophetically, heating the anvil roller 32 and the pattern roller 30 helps to achieve a "glasinado" relief 20 on the resulting paper 10. With reference to Figure 2, the rollers 30, 32 can have a diameter between 8 and 30 inches and preferably a diameter between 18 and 24 inches, a diameter of 10 inches having been found suitable. The rollers 30, 32 can have a length, taken in the axial direction, of eight inches. Preferably, rollers 30, 32 are wider than eight inches to accommodate commercial manufacture. Prophetically, rollers 30, 32 that have a width of 80 inches or more are feasible. The pattern roller 30 and the anvil roller 32 are loaded diametrically together along the plane connecting the centers of the rollers 30, 32. The rollers 30, 32 can be loaded together by pneumatic or preferably hydraulic loading cylinders. Preferably there are P892 a load cylinder at each end of the roller or rollers 30, 32 to be pneumatically charged. Preferably the pattern roller 30 is stationary and the anvil roller 32 is loaded, although if desired, the opposite arrangement could be used. Alternatively, each roller 30, 32 could be pneumatically charged and tilted towards the other roller 30, 32. Load cells can be placed under each roller 30, 32 to equalize the load across the contact point and allow pressure fluctuations of monitoring during embossing. The embossing according to the present invention is given at an embossing pressure of at least about 1,000 psi and preferably between 1,000 and about 10,000 psi and more preferably between about 3,000 and 5,000 psi. The pressure of. Suitable embossing depends on the substrate, in particular the caliper, surface topography and the pulp 10 to be embossed. As the topography of the surface texture increases, a higher embossing pressure according to the present invention is generally required.

Embossing pressure The embossing pressure is determined by the following formula: P892 EP = AL / (NA x PLA) where EP is the embossing pressure, AL is the applied load, NA is the contact area and PLA is the flat area of the pattern The applied load is the sum of the weight of the roller superior embossing (either the pattern roller 30 or the anvil roller 32 as the case may be) and the pressure applied through the loading cylinders used to compress the pattern roller 30 and the anvil roller 32 together. If the loading plane connecting the centers of the anvil roll 32 and the pattern roller 30 is not vertical, only the vertical component of the weight of the upper embossing roller 30, 32 (which is applied to the paper 10) is considered for the determination of the applied load. The contact area is the multiple of the distance of the contact point NW and the width of the pattern roller 30 or of the anvil roller 32. The width of the paper 10 is taken parallel to the axes of the pattern roller 30 or the roller anvil 32. The distance of the contact point NW is taken parallel to the machine direction, as shown in Figure 5. The distance of the contact point NW is dependent on the pressure used to load together the two rollers 30, 32, of thickness T of paper 10, of P892 any - flattening of the rollers 30, 32 or protuberances 34 at the contact point ~ and the diameter of the rollers 30, 32. The distance of the contact point NW can be determined empirically, as is known in the art, by inserting carbon paper at the point of contact between the rollers 30, 32. The rollers 30, 32 are then loaded to the desired pressure. The distance of the contact point NW is then measured from the carbon paper. You can get proper carbon paper in a Nip Impression Kit from Manhattan Division of Beloit Corporation, Beloit Wl. The distance of the contact point NW without the paper 10 to be embossed is interposed between the rollers 30, 32. Instead, only the appropriate carbon paper is used to determine the distance of the contact point NW. To determine the distance of the contact point NW, the rollers 30, 32 are rotated to the desired position, described below, for the measurement of the distance of the contact point NW. Once the rollers 30, 32 are in the desired position, they are loaded together with the pressure used for the process according to the present invention. The charge generates an impression of the point of contact in the carbon paper. This impression is measured in the machine direction, using any scale P892 suitable, to give the distance of the contact point NW. Appropriate scales that are 1/32 of an inch resolution are available from Starrett Company, Athol, Massachusetts. With reference to Figure 5, when the distance of the contact point NW is found, the rollers 30, 32 are rotated to the desired position, so that a repeating unit 40 of the master roller 30 centers at the point of contact. The example of Figure 5 illustrates diamond-shaped and circular repeat units 40, although it will be admitted that any desired shape of the repeating unit 40 according to the present invention can be used. If the pattern roller 30 has more than one size of the repeating unit 40, the largest repeating unit 40 having the largest size is centered at the point of contact for the determination of the distance of the contact point NW. The size of the repeating unit 40 is considered only in the machine direction when the distance of the contact point NW is determined. If two (or more) repeating units 40 have the same large size in the machine direction, then the repeating unit 40 having the largest size in the cross machine direction is used to determine the distance of the point of contact NW. If two pattern rollers 30 are used, the pattern roller is used P892 having the largest repetition unit 40 for the determination of the contact point distance. As noted above, the pattern roller 30 has a flat pattern area associated with it. The planar area of pattern is determined by the area of distal ends 36 of the protuberances 34. The planar area of pattern is the percentage of the surface area of the pattern roller 30 that actually makes contact with the paper 10 during embossing. This percentage corresponds to the cumulative surface area of distal ends 36 of the radially extending protuberances 34 as a percentage of the surface area of the roll of the pattern roller 32. Preferably the pattern planar area comprises between about 2 and 20 percent and with greater preferably between about 3 and 10 percent of the surface area of the pattern roller 30. The pattern flat area can be determined mathematically by knowing the geometry of the rollers 30, 32 and the distal ends 36 of the protuberances 34. Preferably the embossing pattern defined by the protuberances 34 comprises a series of discrete protuberances 34, rather than a continuous line. The discrete protuberances 34 are less likely to cut the paper 10 than the protuberances 34 that are comprised in a continuous line.

P892 The planar area of the pattern has an associated width of a flat portion of the pattern. The width of the flat portion of the pattern is the narrowest dimension of the distal end 36 of the protrusion 34. Preferably the width of the flat portion of the pattern is at least about 0.020 inches and more preferably at least about 0.030. inches If the width of the flat portion of the pattern is less than that specified above, the pattern roller 30 will cut the paper 10. The cut, in particular, will occur with the paper 10 manufactured as a tissue product, even at relatively low embossing pressures, for example at 2,000 psi, with widths of flat portion of the pattern narrower than those specified above. The protuberances 34 may extend radially between 0.010 and 0.070 inches and preferably about 0.025 inches outward from the periphery of the pattern roller 30. In operation, the process according to the present invention may be carried out by providing two axially parallel rollers 30, 32 juxtaposed together to form a point of contact between them. Each of the rolls 30, 32 has an axis. Each roller 30, 32 rotates about its axis. The axes of the rollers 30, 32 define a load plane connecting the centers of the rollers 30, 32. Each of the rollers 30, 32 is relatively P892 incompressible and preferably is made of steel. At least one of the rollers 30 has a plurality of protuberances 34 that extend radially outwardly thereof. Each protrusion 34 has a distal end 36. The other roller 32 can be relatively smooth. The rollers 30, 32 are loaded diametrically together along the loading plane connecting the centers of the rollers 30, 32. The rollers 30, 32 are loaded together with an embossing pressure of at least about 1,000 psi, measured at the distal ends 36 of the protrusions 34. A single sheet of paper 10 is also provided. Generally, a single sheet of paper 10 having a relatively high gauge and a relatively high basis weight is preferred, so that the aesthetic clarity of the reliefs 20 is taken to the maximum. Also, preferably, the simple sheet of paper has a relatively fine surface topography compared to the pattern of the desired reliefs. More preferably the surface topography is determined by the size of the deflection conduits used in a papermaking dryer band used to make the paper 10. The paper 10 has opposite first and second surfaces 12, 14 opposite which are separated in the direction Z by the thickness T of the paper 10. The paper 10 is P892 interposed at the point of contact between the rollers 30, 32. Each roller 30, 32 is rotated about its respective axes, whereby the paper 10 is transported with respect to the rollers 30, 32 through the contact point . The paper 10 is embossed at the contact point to provide a plurality of reliefs 20 corresponding to the distal ends 36 of the protuberances 34. The relief bottom 20 is disposed between the first and second surfaces 12, 14 of the paper 10. The reliefs 20 do not extend out of the plane of the paper 10. Preferably the embossments 20 are "glasinados".

Example I It has been found that the process according to the present invention works well with a smooth anvil roller 32 and a pattern roller 30 having 28 discrete protuberances 34 per square inch. Each protrusion 34 was elliptically formed and had shafts greater than and less than 0.080 inches and 0.040 inches, respectively. The protuberances 34 were spaced at a slope of 45 ° to 0.117 inches. The rollers 30, 32 were ten inches in diameter, a flat area of 8 percent pattern and were loaded at a distance from the contact point NW of 0.18 inches to a P892 5,300 psi embossing pressure. The single sheet of paper 10 was made according to the United States Patent assigned jointly 4, 191,609, granted to Trokhan and which is considered part of the present, as reference. This paper 10 had approximately 1450 domes per square inch bilaterally staggered. Paper 10 had a basis weight of 18 pounds per 3,000 square feet and a triple layer structure of 35% eucalyptus in the two outer layers and 30% in the central layer, nominally. The resulting reliefs 20 were "glasinados" and had a pleasant and distinctive aesthetic clarity in relation to the bottom of the paper 10.

Example II This experiment was repeated with a simple sheet of paper 10 made according to commonly assigned U.S. Patent 4,637,859. Paper 10 had a bow-shaped pattern with approximately 78 domes per square inch. This simple sheet of paper 10 was not embossed in an acceptable manner according to the present invention. The same embossing pattern that worked well in the previous example, in this example was neither distinguished from the background nor aesthetically pleasing. Alternatives to the process described above are within the scope of this invention. For example, if one P892 would like to produce a paper 10 according to the present invention having reliefs 20 extending inwards both from the first side 12 and from the second side 14 of the paper 10, where the reliefs 20 are offset or displaced from each other, one could replace the rollers 30, 32 described above with the double sheet rolling rollers 30 disclosed in the aforementioned incorporated U.S. Patent 5,294,475 issued to McNeil. Each of the rollers 30 in the '475 McNeil patent has radially extending protrusions 34. The protrusions 34 of each radially extending roller contact the periphery of the other roller 32, 30. If one wishes to produce a paper 10 according to the present invention having reliefs 20 extending inward from the first side 12 and from second side 14, where the embossments 20 are in register or coincidence with one another, one could use the emboss protrusion process disclosed in the aforementioned incorporated US Patent 3,414,459 issued to Wells. Each roller in the '459 patent of Wells also has radially extending protrusions 34. The radially extending protuberances 34 of a roller 30 contact the radially extending protrusions 34 of the other.

P892 roller 30. Alternatively, if one wishes to completely avoid the use of rollers 30, 32 in the embossing according to the present invention, one could use flat plates in the embossing process. A flat plate serves as an anvil plate. The other flat plate has a pattern as described above. As mentioned above in relation to the rollers 30, 32, the plates must be rigid and non-deformable. Preferably, the plates are held reciprocally parallel and loaded together perpendicular to at least one of the plates. A flat plate embossing process has the disadvantage that it involves a batch process, rather than the continuous process described above. Although, prophetically, a flat plate embossing process provides the advantage of a longer contact time with the paper 10, thereby improving the aesthetic distinction of the embossments 20.

P892

Claims (10)

1. CLAIMS; 1. A process for embossing a simple sheet of paper, the process comprising the steps of: providing two axially parallel rollers juxtaposed to form a contact point between them, each of the rollers has an axis, the axes of the rollers define a loading plane connecting the centers of the rollers, at least one of the rollers has a plurality of protuberances extending radially therefrom outwardly to an equivalent plurality of distal ends, each of the rollers being relatively incompressible; loading the rollers together in the loading plane with an embossing pressure of at least 1,000 psi at the distal ends of the protuberances; providing a simple sheet of paper having first and second opposite sides separated by the thickness of the paper; interpose the paper at the point of contact between the rollers; rotating each of the rollers around their respective axes, whereby the paper is transported relative to the rollers; and embossing the paper to provide a plurality of inwardly extending embossments, P892 corresponding to the distal ends of the protuberances, the reliefs are intermediate to the first side and to the second side of the paper, so that the reliefs do not extend outwards beyond each side of the paper. A process according to claim 1, wherein one of the rollers has protrusions extending therefrom and one of the rollers has a relatively smooth surface and preferably the step of embossing the paper produces paper having reliefs that extend unidirectionally inward from one side of the paper. A process according to claim 1, wherein the paper is air-dried and has domes extending outwardly from the first side of the paper and preferably the paper is interposed at the point of contact with the domes oriented in opposite direction to the protuberances, so when embossing the reliefs extend inward from the second side of the paper. 4. A process for embossing a simple sheet of paper, the process comprising the steps of: providing two axially parallel rollers juxtaposed to form a point of contact between them, each of the rollers has an axis, the axes of the rollers define a loading plane that connects the centers of the rollers, each of the rollers has a P892 plurality of protuberances extending radially from there to the outside, each protuberance ends at a distal end; loading the rollers together in the plane to provide an embossing pressure of at least 1,000 psi at the distal ends of the protrusions, - providing a single sheet of paper having two opposite sides, a first side and a second side, the first side and the second side are separated by the thickness of the paper; interpose the paper between the rollers at the point of contact; rotating each of the rollers around their respective axes, whereby the paper is transported relative to the rollers; and embossing the paper to provide a plurality of embossments extending inwardly from the first side of the paper to the second side of the paper and a second plurality of embossments extending inwardly from the second side of the paper to the first side of the paper . The process according to claim 4, wherein the protuberances of each roller contact the periphery of the other roller at the point of contact, wherein when embossing the paper the first plurality of reliefs P892 and the second plurality of reliefs are reciprocally offset from one another and, preferably, the embossing pressure is at least 3,000 psi. The process according to claim 4, wherein the distal ends of the protuberances in each roller contact the distal ends of the protuberances in the other roller at the contact point, so that the first plurality of reliefs and the second plurality of reliefs are put in register with each other and preferably the rollers are loaded together with a pressure of at least 3,000 psi. 7. A simple sheet of paper having two opposite sides, a first side and a second side, the paper to be embossed and having reliefs extending inward from one side of the paper to the other side of the paper, through so that the reliefs do not extend outward from each side of the paper, preferably the reliefs comprise glasinated regions on the paper and more preferably the paper has domes extending outward from the first side of the paper and even more preferably the reliefs extend inward from the second side towards the first side and preferably superlative each of the reliefs has a larger area than each of the domes. 8. A simple sheet of paper that has two P892 opposite sides, a first side and a second side, the simple sheet of paper has reliefs extending inward from each first side and second side, the paper having no reliefs extend outward from each side, the intermediate area a the reliefs remain relatively undisturbed. 9. The paper according to claim 8, the reliefs are in register or coincidence, wherein the reliefs extending inward from the first side correspond in position to the reliefs extending inwardly from the second side. 10. The paper according to claim 8, the reliefs are offset, wherein the reliefs extending inward from the first side do not correspond in position to the reliefs extending inward from the second side. P892