MXPA00002665A - Embossed, joined laminae having an essentially continuous adhesive network and juxtaposed thereon the embossments - Google Patents

Abstract

A laminate (10) having two or more plies (12). The plies (12) are embossed, and adhesively joined together. The adhesive (30) forms an essentially continuous network. The essentially continuous network increases the strength of adhesive, increases the strength of the laminate (10), and is disposed within the X-Y plane of the laminate coincident the embossments (60).

Description

LAMINATED MATERIALS UNITED, IN RELIEF, THAT HAVE AN ADHESIVE NETWORK ESSENTIALLY CONTINUOUS AND YUXTAPOSED IN THE RELIEFS FIELD OF THE INVENTION The present invention relates to several layers of paper having reliefs, joined together to form a laminated product, and more particularly to the bonding of layers using adhesive to improve the strength and bond the reliefs, and the material laminate produced in this way. BACKGROUND OF THE INVENTION Several layers of paper have been adhesively bonded together in a face-to-face relationship using well-known techniques. A commercially successful and particularly suitable technique is found in joint patent No. 5,143,776, granted on September 1, 1992 to Givens and which is incorporated herein by reference. The joining of several layers of paper together by the formation of embossments is well known in the art. The relief formation can be achieved by adhering corresponding distant surfaces of protuberances to form a laminated product in the form of corresponding protrusions. The formation of corresponding projections is described in the joint North American patent No. 3,414,459, granted on December 3, 1968 to Wells, which is incorporated herein by reference. An example of a useful pattern with a relief of corresponding protruding type is presented in the joint North American patent Des. 239,137, granted on March 9, 1976 to Appleman and which is incorporated herein by reference. Appleman illustrates an embossed pattern found on commercially successful paper towels. A variation of the relief type corresponding salient is presented in the North American document 5,443,889, granted on August 28, 1995 to Ruppel et al. Another type of relief is the relief in the form of a nest where the reliefs attached adhesively are mutually displaced in accordance with that illustrated in US Pat. Nos. 3,547,723, issued on December 15, 1970 to Gresham; 3,556,907, granted on January 19, 1971 to Nystrand; 3,708,366, granted on January 2, 1973 to Donnelly; 3,738,905, granted on June 12, 1973 to Thomas; 3,867,225, granted on February 18, 1975 to Nystrand; and 4,483,728, granted on November 20, 1984 to Bauernfeind. Another type of relief is found in the joint North American patent 5,294,475, granted on March 15, 1994 to McNeil and which is incorporated herein by reference. McNeil presents a double-layer lamination where a multi-layer laminate is produced that has an appearance in the form of a thick, cushioned fabric.

A feature common to each and every one of the three embossing techniques mentioned above is that in each case the reliefs of the paper are deflected out of the plane of the paper by the protuberances of the embossing rollers. The adhesive that joins the folds is then applied on the projections of the paper. The layers are then joined together in a face-to-face relationship with the adhesive. These techniques permanently bind the layers in a face-to-face relationship. Unfortunately none generates strength within the plane of the resulting laminate. The formation of reliefs has also been used to provide aesthetic characteristics to the resulting laminate material as presented in GB 2 225 745A, published on November 18, 1992 by Chandler; in US Patents Nos. 5,620,776 granted on April 15, 1997 to Schulz; and 4,978,565, granted on December 18, 1990 to Pigneul et al. Another additional technique for providing aesthetic characteristics to a laminate is printing, in accordance with that disclosed in US Pat. No. 5,209,953, issued May 11, 1993 to Grupe et al. Unfortunately, none of these methods to provide aesthetically pleasing features to the laminate improves its strength. Attempts to improve resistance are illustrated in US Pat. Nos. 4, 522,863, granted on June 11, 1985 to Keck et al. and 4,915,993, granted on April 10, 1990 to Ten Wolde. Keck et al. and Ten Wolde present laminated products that have a middle layer consisting of canvas or a reinforcing fabric of the reticulated type. Both the canvas and the reinforcing fabric are distinct, separate, continuous layers added to the center of the laminate. Unfortunately, this approach to generating resistance requires an additional layer interposed between the two outer layers. The multiple layers must be adhesively bonded to form the desired unitary laminate. A commercially successful attempt to provide an essentially continuous network to a single layer of paper is found in joint US Patent No. 4,637,859, issued on January 20, 1987 to Trokhan, which patent is incorporated herein by reference. Trokhan presents an elaborate paper in a biasing member having an essentially continuous web printed against a surface such as, for example, a Yankee drying drum to form an essentially continuous pattern. Accordingly, it is an object of the present invention to provide a multilayer laminate. Furthermore, it is an object of the present invention to provide a laminated material having the layers with relieves therebetween. It is finally an object of the present invention to provide said laminated material with a continuous crosslinking of adhesive which provides strength to the laminated material. COMPENDIUM OF THE INVENTION The invention relates to a laminated material. The laminate comprises two or more layers adhesively bonded in a face-to-face relationship. The adhesive is interposed between the layers in an essentially continuous network. The layers are embossed through a plurality of projections. The projections are deformed in a normal manner in relation to the plane of the laminated material and preferably towards the other layer. The layers are adhesively bonded together on the projections. The projections coincide in the essentially continuous network of adhesive. In another embodiment, the invention comprises a process for making a laminate material of two or more layers joined in a face-to-face relationship. The process comprises the steps of providing at least two layers to be joined in a face-to-face relationship. The layers are embossed together so that the first face of the first layer is joined in face-to-face relationship with the first face of the second layer whereby the first layer and the second layer are joined together by several projections. The various projections coincide in the essentially continuous network of adhesive. DESCRIPTION OF THE DRAWINGS Figure 1 is a perspective elevation view of a laminate according to the present invention, which has the layers partially separated for reasons of clarity. Figure 2 is a schematic side elevational view of an apparatus that can be employed to carry out the present invention. Figure 3 is a top plan view of the inner face of a layer of a laminate material in accordance with the present invention, and having two essentially continuous different crosslinkings of adhesive. Figure 4A is a top plan view of the inner face of a layer of a laminate material in accordance with the present invention, and having a continuous crosslinking of adhesive superimposed on an adhesive pattern comprising discrete closed figures. Figure 4B is a top plan view of the inside face of a layer of an embossed pattern illustrated in Figure 4A and having an adhesive pattern comprising discrete closed figures that do not follow the outline of the projections, but is exaggerated to more closely match the space between adjacent lines of adhesive. Figure 4C is a top plan view of the inside face of a laminate having an adhesive pattern that is a hybrid of the patterns illustrated in Figures 4A and 4B. DETAILED DESCRIPTION OF THE INVENTION With reference to Figure 1, the present invention comprises a laminate material 10. The laminate material 10 comprises a plurality of two or more layers 12. Although the following comments are made in relation to the two layers 12, one skilled in the art will understand that the laminate 10 it can comprise a number of layers 12 greater than 2. Each individual layer 12 of the laminate material 10 has a first face 20 and a second face 22. When the layers 12 are joined together in a face-to-face relationship, each layer 12 has a inner face 20 and an outer face 22. The first face or inner face 20 of each layer 12 is oriented towards the other layer 12. The second face or outer face 22 of each layer 12 faces the opposite side of the other layer 12. Each layer 12 according to the present invention can be conventionally dried or air dried. Preferably, the paper comprising the layer 12 is either air dried or conventionally dried in accordance with that indicated in any of the US Patents Nos. 4,191,609, issued to Trokhan.; 4,514,345, issued to Johnson et al .; 4,528,239, awarded to Trokhan; 4,529,480, awarded to Trokhan; 5,245,025, awarded to Trokhan; ,275,700, awarded to Trokhan; 5,328,565, issued to Rasch et al .; 5,334,289, awarded to Trokhan; 5,364,504, issued to Smurkoski et al .; 5,527,428, issued to Trokhan et al .; 5,556,509, issued to Trokhan et al .; 5,628,876, issued to Ayers et al .; 5,629,052, issued to Trokhan et al .; and 5,637,194, issued to Ampulski et al., whose disclosures are incorporated herein by reference. Optionally, the paper in accordance with the present invention can be pre-coated. The optional pre-coupling can be achieved by crepe formation or wet microcontraction. Crepe and wet microcontraction are presented in the joint United States Patents 4,440,597, granted to Wells et al., And 4,191,756, granted to Sawdai, whose disclosures are incorporated herein by reference. The layers 12 are adhesively bonded together in accordance with what is described below. A suitable adhesive 30 is a water based adhesive. Preferably, the adhesive 30 comprises polyvinyl alcohol. The polyvinyl alcohol can be added to the adhesive 30 in the amount of 3 to 7% by weight, and preferably about 5% by weight. If desired, a polyamide resin and more particularly a cationic polyamide resin can be added to the adhesive 30. The addition of a polyamide resin increases the wet strength of the layers 12 and increases the bond strength of layers between the layers 12 of the laminate material 10. A suitable polyamide resin is KYMENE, sold by Hercules Chemical Company. If KYMENE is selected for the polyamide resin, it may be applied in the amount of about 1 to 5% by weight, preferably about 2 to 4% by weight, and especially about 2.5% by weight. The adhesive 30 can be applied in an essentially continuous pattern, in accordance with that illustrated in Figures 3-4. The adhesive 30 can be applied to one or both layers 12 of the laminate 10 in an essentially continuous pattern. An essentially continuous pattern is described in the aforementioned incorporated US Patent No. 4,637,859. With reference to Figure 2, the adhesive 30 can be applied by any means known in the art, including spraying, flexographic printing, as well as etching. If the adhesive 30 is sprayed, meltblown, spiral adhesive patterns 30 are formed as is known in the art to be suitable patterns, as well as by spraying the desired pattern from a spray nozzle. In the case of engraving, the apparatus 40 of Figure 2 may be employed. The apparatus 40 comprises three pairs of axially parallel adhesive rolls in the following order: an engraving roll 44, an applicator roll 48, and a printing cylinder 50. The adhesive 30 is placed in a tank 42 and withdrawn from the tank 42 through the engraving roller 44. An excess of adhesive 30 is supplied by means of a handling system 46. The adhesive 30 is transferred from the platen roller. engraving 44 to the applicator roller 48. The printing cylinder 50 is juxtaposed with the applicator roller 48. The layer 12 passes between the applicator roller 48 and the printing cylinder 50. The adhesive 30 is preferably applied to the first inner face 20 of layer 12 by applicator roll 48. Adhesive 30 can be applied in an essentially continuous pattern, which resembles a cross-linked or any other suitable pattern. A similar and corresponding apparatus 40 can be provided to print the other layer 12. With such an apparatus 40, the adhesive 30 can be included in each layer 12 in the form of a predetermined pattern. Preferably the two applicator rollers 48 are in phase with each other, even indirectly, in such a way that the desired adhesive pattern 30 of one layer 12 corresponds in its position to the desired pattern of the adhesive 30 of the other layer 12. Obviously, it will be recognized that it is unnecessary for both applicator rolls 48 to print the entire continuous network in the respective layers 12. A portion of the pattern, for example, the portion of the pattern in the machine direction, can be printed by means of the applicator roller 48 associated with the first layer 12. Another portion of the pattern, for example, the portion in the transverse direction in relation to the machine it can be printed by means of the applicator roller 48 of the second layer 12. When the two layers 12 are combined, the complete crosslinking is obtained, forming the essentially continuous network. After the application of the adhesive 30 on the first layer 12, the second layer 12, or both layers, the layers 12 pass through two pattern rollers 52 for the formation of reliefs. The pattern rolls 52 may be of the type described in the aforementioned incorporated US Patent 5,294,475. Alternatively, the pattern rollers 52 may be of the type useful for relief formation of corresponding protrusions or nest type, as is commonly known in the art. Pattern rollers 52 suitable for relief formation of corresponding protrusions are presented in the aforementioned US Pat. No. 3,414,459. Pattern rollers 52 suitable for nest-like relief formation are presented in U.S. Patent No. 3,556,907. The applicator roller 48 and the control roller 52 may be in phase with each other using devices (not illustrated) well known in the art. For example, the applicator roller 48 and the pattern roller 52 can be geared together. The two pattern rollers 52 may also be meshed together in order to ensure that a desired correspondence between the two layers 12 is obtained. Alternatively, a fixed drive shaft may be employed in an in-line phase adjuster. The in-line phase adjustment can be achieved through an in-line sun and planetary gear system connected between the drive motor for the system and one of the rollers to be phased as is known in the art. A suitable phase adjuster is the adjuster developed by Cone Drive Operations, Inc., of Traverse City, Michigan. Alternatively, the phasing can be achieved by changing the path length of the layer 12 between the two rollers that it is desired to place in phase. The path length can be changed by placing a guide roller in the path of the tissue, and adjusting the guide roller in a direction having a vector component perpendicular to the tissue path. All of these devices for providing phase placement are known and do not form part of the present invention. As illustrated in Figure 3, the projections 60 preferably comprise a repetitive, non-random pattern. More preferably, the projections 60 are mutually discrete. Mutually discrete projections 60 are separated from each other by essentially continuous regions without relief. A suitable and commercially successful pattern of reliefs 60 comprises diamond shapes, as illustrated. It is important to recognize that while a plurality of reliefs 60 together form a diamond-like pattern, each individual projection 60 may have a shape independent of the pattern it creates in combination with other projections 60. For example, an individual projection 60 may have an oval shape , as shown, a circular, rectangular, square, etc. The rolled material 10 has a direction in the machine direction and a transverse direction perpendicular in relation to the machine direction. The protrusion pattern 60 may have a primary orientation positioned at an angle relative to the machine direction and transverse direction. For example, the pattern illustrated in Figure 3 has a primary orientation of either side of a rhombus placed at a 45 degree angle, cutting the vectors in a direction parallel to the machine and transverse to the machine. The essentially continuous pattern of adhesive 30 can be placed in a pattern having a primary orientation which is exclusively placed diagonally in relation to the machine direction and transverse direction in relation to the machine. This arrangement allows the creation of a network having a space between adjacent lines of adhesive 30 corresponding and identical to the distance between adjacent rows of reliefs 60. If the essentially continuous network of adhesive 30 is aligned exclusively in the machine direction and in the transverse direction in relation to the machine, and coincides with all the reliefs 60 or at least most of the reliefs 60, the adhesive lines 30 would be spaced relatively narrowly. Overly closely spaced adhesive lines 30 are not desired since this spacing increases the cost of the resulting laminate 10, unduly reduces the absorption capacity of the laminate 10, and has a negative impact on the user's perception of as to the soft character of the laminated material 10. If desired, an essentially continuous network of adhesive 30 having primary orientations in the parallel direction relative to the machine and in the transverse direction relative to the machine can be superimposed on the first network of essentially continuous adhesive 30 having a primary orientation placed exclusively on a diagonal with respect to the machine direction and with respect to the transverse direction of the machine. This pattern allows having two different spacings. The first spacing corresponds to the space between adjacent repetitive unit cells of projections 60. The second space corresponds to the spacing between adjacent rows of projections 60. With reference to Figure 4A, the pattern of adhesive 30 may further comprise discrete closed figures. Obviously, as discussed above, the discrete closed figures may correspond to similar patterns of projections 60. This arrangement provides for the layer 12 the joining of the first layer 12 on the second layer 12 together, without requiring an exaggerated amount of adhesive 30. for joining the projections 60 spaced closely. This arrangement minimizes the use of adhesive 30, thus reducing the losses of the soft character of the laminate and its absorption capacity. With reference to Figure 4B, it should be recognized that for similar patterns of the projections 60, various patterns of adhesive may be employed. The adhesive pattern 30 in Figure 4 is exaggerated in relation to the closed figures formed by the projections 60. Instead of following in an identical and close way the figure formed by the projections 60, the adhesive 30 extends outwards beyond of said closed figure. This arrangement has the advantage of allowing a more equal spacing of adhesive lines 30 to be obtained. In fact, it will be recognized that for predetermined distances, the adhesive lines 30 are mutually parallel. With reference to Figure 4C, a pattern of hybrid adhesive 30 is shown for the same pattern of projections 60 illustrated in Figures 4A and 4B. In the adhesive pattern 30 of FIG. 4C, alternative closed figures have an adhesive pattern 30 that follows in an identical manner the profile of the closed figures. Other closed figures have an adhesive pattern 30 which is exaggerated in order to equalize the spacing between adjacent lines of adhesive 30. This arrangement provides in a prophetic manner the advantage of articulation lines, for flexibility, between the closed figures that have the lines surrounding adhesives 30. It will be recognized that there are many other combinations, changes and variations in relation to the claimed invention. For example, the reliefs 60 do not have to be limited to the oval shapes illustrated, but may have any desired shape. In addition, relief patterns 60 do not have to consist of numerous discrete reliefs 60 juxtaposed to form a pattern. On the contrary, the pattern can be formed by continuous lines of reliefs 60 as is known in the art. All these combinations, changes and variations are within the scope of the following claims. The laminate 10 made according to the present invention can be perforated and rolled, as is known in the art. Apparatus suitable for perforating, cutting and rolling the laminate 10 are well known in the art and are found in the joint United States Patents 4, 687,153, granted on August 18, 1987 to McNeil and 5,660,350, granted on August 26, 1997 to Byrne et al., Whose disclosures are incorporated herein by reference. Alternatively, the laminate 10 according to the present invention can be cut into discrete units, as is usually done in the case of facial tissues, handkerchiefs, napkins, rags, etc. An example of packaging for discrete handkerchiefs, for example, is found in joint US Patent 5,664,897, issued July 8, 1997 to Young et al., Which is incorporated herein by reference. It will be understood that the packaging and uses of the laminate 10 according to the present invention are not limited to those described herein. The laminate 10 according to the present invention can be packaged, shipped and used in various suitable formats.

Claims (1)

1. CLAIMS A laminated material comprising: two or more layers joined together in a face-to-face relationship with adhesive, said adhesive being placed between said layers in an essentially continuous network; and a plurality of reliefs, said reliefs are deformed in a normal manner in relation to said laminated material and adhesively bond said layers therein, said reliefs coinciding with said essentially continuous network of said adhesive. A laminated material according to claim 1, wherein said relieves comprise a repetitive non-random pattern. A laminated material according to claim 2 wherein said relieves are mutually discrete. A laminated material according to claim 3 wherein said pattern of said reliefs comprises a diamond-shaped pattern. A laminated material according to claim 4 wherein said laminate has a direction in the machine direction and a direction transverse to the direction of the machine perpendicular to the direction in the direction of the machine, and said relief pattern has an orientation primary positioned diagonally relative to said machine direction and said transverse direction relative to the machine. 6. A laminated material in accordance with the claim 5 wherein said essentially continuous network of said adhesive material has a primary orientation generally aligned with said machine direction and said transverse direction relative to the machine. 7. A laminated material in accordance with the claim 6 further comprising an essentially continuous network of adhesive having a primary orientation positioned diagonally relative to said machine direction and said transverse direction relative to the machine. 8. A laminated material according to claim 2 further comprising discrete closed adhesive figures corresponding to discrete patterns of said reliefs. 9. A laminated material according to claim 1 comprising two layers, a first layer and a second layer, said first layer and said second layer are adhesively joined to each other by means of reliefs of corresponding projections, each of said first layer and said second layer has reliefs there, said reliefs of said first layer correspond to said reliefs of said second layer. 10. A laminated material comprising two layers joined together in a face-to-face relationship, each of said layers having an internal face facing said other layer and an opposite and oriented external face away from said first layer, each said First layer comprises reliefs and a region without relief, said reliefs are oriented towards the other layer, compressed against the other layer and adhesively bonded against the other layer in its region without relief, whereby said layers are joined together with adhesive, said adhesive it is interposed between said layers in an essentially continuous network. 11. A laminated material according to claim 10 wherein said relieves comprise a non-random repeating pattern. 12. A laminated material according to claim 11 wherein said relieves are mutually discrete. 13. A laminated material according to claim 12 wherein the pattern of said reliefs comprises a diamond-shaped pattern. A laminated material according to claim 13 wherein said laminate has a machine direction and a direction transverse to the machine perpendicular to the machine direction, and said pattern of reliefs has a primary orientation placed diagonally in relation to said machine direction and in relation to said transverse direction of the machine.