Patent Application
20080032099
As shown in
The paper sheet includes fibers that are joined together by binders and other known paper ingredients, and the paper fibers may be woven or unwoven. Preferably, the paper sheet 10 is a cotton-based paper sheet that has an uncoated basis weight of between about 13 to about 14 pounds per ream. The paper sheet 10 is preferably of the cotton rag variety, and is more preferably 100% cotton rag. The paper sheet 10 further preferably has a medium to high porosity as measured by the standard gurley test of approximately 500 seconds (+ or −100 seconds) per 100 cc. An exemplary paper sheet 10 suitable for use in the present invention is marketed by the Esleeck Paper Mill, Turners Falls, Mass. under the trademark “NAME NATURAL TRACING BOND.”
The adhesive coating 16 is comprised of thermoplastic resin, such as ethylene acrylic acid (“EAA”). A preferred adhesive coating 16 is an extrusion type resin such as that sold by Dow Chemical Corporation of Midland, Mich. sold under the trademark PRIMACOR #3330. However, other thermoplastic resins may be used either alone or together with EAA, including but not limited to ethylene methacrylic acid (“EMA”), copolymers, and combinations thereof. For example, the thermoplastic resin may be an extrusion resin comprising a ethylene-methacrylate copolymer having a methacrylic acid content of 8% by weight and an MFR of 8 g/10 minutes, such as that marketed as Newcrel 0908C by Mitsui Dupont Polychemical Co.
The adhesive coating 16 is applied in a discontinuous manner to yield discrete areas of adhesive coating 16 on the surface of the paper, the adhesive areas divided by substantially uncoated areas 18. The coating 16 is preferably applied using rotogravure hot cylinder coating methods. In one example, the coating 16 comprising EAA resin was applied to both sides 12, 14 of an uncoated web of a 100% cotton fiber sheet 10 using a 55-line quad rotogravure hot cylinder. In this embodiment, the coating 16 was applied by making two passes on the coating line, one pass per side 12, 14 to produce a double-sided adhesive coated paper, as shown in
The coated paper sheet 8 of the present invention includes a discontinuous coating pattern that includes raised portions 17 are formed by the adhesive coating 16 and the substantially uncoated areas 18 interposed between the raised portions 17 of the coated areas. For example, the pattern of the adhesive coating 16 may be symmetric or asymmetric. By way of further example, the surface area covered by the raised portions 17 of the adhesive coating is roughly equal to the surface area of the substantially uncoated areas 18, so that upon lamination the adhesive forms a substantially uniform coating 16 between the paper sheet 10 and the art item 30, or between the sheet 10 and the substrate 20. After lamination, the substantially uniform coating 16 is substantially free of bubbles and other forms of trapped air.
As shown in the example of
In another example shown in
In one method of using a double-sided embodiment of the adhesive mounting paper 8 of the invention, a heated piece of mounting equipment, such as a mechanical or vacuum press, is heated to a temperature sufficient to melt a thermoplastic adhesive coating 16 of a provided adhesive mounting sheet 8. A sheet art item 30, such as a photograph or art print, is provided. The art item 30 is placed in contact with a first side 14 of the previously described discontinuous adhesive mounting sheet 8. A substrate 20 is provided, and is placed in contact with the opposite exposed side 12 of the mounting sheet 8. The resulting sandwich (comprised of the art sheet 30, mounting sheet 8, and rigid substrate 20) is placed in a heated press, and is exposed to heat and mechanical pressure for a time sufficient to melt the adhesive coating 16 of the mounting sheet 8. The melted adhesive coating 16 adheres to the art sheet 30 and substrate 20, as well as to the paper sheet 10, thereby forming a multiple-layered laminated art product.
Next, the laminated mounted art product is removed from the press and allowed to cool, whereupon the adhesive coating 16 sets to form a permanent bond, retaining its desirable flexibility and adhesive properties simply upon cooling back to ambient temperature. Notably, the adhesive 16 coating, being a thermoplastic resin, does not require any additional time to set, and does not undergo any chemical curing or cross-linking after setting, thus permitting a long-lasting, chemically and mechanically stable mounting with virtually no degradation over time.
While the invention has been described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims.
