Stock material or miscellaneous articles – Structurally defined web or sheet – Discontinuous or differential coating – impregnation or bond
Reexamination Certificate
2002-01-11
2004-10-26
Kelly, Cynthia H (Department: 1774)
Stock material or miscellaneous articles
Structurally defined web or sheet
Discontinuous or differential coating, impregnation or bond
C428S914000, C428S411100, C428S195100
Reexamination Certificate
active
06808792
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention concerns transfer foils for applying a decorative layer arrangement formed by at least one lacquer layer and a heat-activatable adhesive layer to a substrate.
Safeguarding documents is becoming increasingly important, in which respect the term “documents” is used to mean not only identity papers, value-bearing papers or stocks and shares or the like but for example also banknotes, cheques, credit cards etc. Value-bearing documents, for example banknotes, very frequently involve using security elements formed by a decorative layer arrangement which for example includes structures having an optical-diffraction or holographic effect. In addition however it is also possible to provide given graphic configurations as security elements. In the case of value-bearing documents issued in large numbers the security elements are very frequently applied by means of a transfer foil, for example a hot stamping foil, in which case the decorative layer arrangement forming the security element usually includes at least one lacquer layer and a layer of a heat-activatable adhesive which serves to join the lacquer layer or assembly of lacquer layers which represent the actual security element, to the substrate, for example a banknote, a cheque, an identity document or a credit card.
In most cases the operation of transferring the security element onto the document is effected by machine. In that situation processing of transfer foils, mostly so-called hot stamping foils, gives rise to few problems if the machines are of a suitable design.
The decorative layer arrangements of hot stamping foils are only of very small thickness. They comprise essentially only some lacquer layers. The advantage of this small thickness of the security elements is that, when the security elements are arranged only in a given region of the document, there are nonetheless no fundamental differences in thickness in the document. Such differences in thickness could in fact give rise to problems in regard to the stacking operation. A further advantage of using decorative layer arrangements comprising a plurality of lacquer layers as security elements is that layer arrangements of that kind are mechanically not very stable. If therefore the attempt is made to pull a security element off the document, it is virtually safe to assume that the security element comprising the various lacquer layers will be destroyed so that the forgery or the attempt at forgery can be easily detected.
The use of hot stamping foils for applying security elements to documents does however suffer from the disadvantage that it is always necessary to incur a corresponding amount of machine expenditure because applying hot stamping foil decorative layers as security elements to substrates by hand is practically impossible, more specifically because of the very small thickness of the decorative layer arrangement of a hot stamping foil. This means that for specific situations of use, the use of hot stamping foils as a security element was hitherto out of the question because the machine expenditure required would not have been in reasonable relationship with the result attained.
In certain cases it would moreover be highly advantageous if a security element could be individualised before being applied to a document. That option is worthwhile in particular in relation to personal documents. It would then be possible to use a security element which, before being applied to the document, was individualised with personal data of the owner of the document, for example a photograph, name or date of birth etc. That possibility is out of the question in a practical context if security elements are transferred onto a document by means of a known hot stamping foil, more specifically in particular for the reason that individually printing security elements which are always present in very large numbers on hot stamping foils is once again out of the question, because of the expense involved, if only a few, correspondingly individualised security elements are required. By way of example the situation is such that only very few security elements with person-related data are always required for personal identifications, passports etc. Frequently even one such element is sufficient, which is then a component part of the personal identification or passport.
SUMMARY OF THE INVENTION
Now, the object of the invention is to provide a transfer foil by means of which it is possible to transfer a security or decorative element which in terms of its structure basically corresponds to the decorative layer arrangement of a per se known hot stamping foil, wherein application of the decorative layer arrangement to the substrate, for example a document, is to be possible, even without extensive machine equipment.
In accordance with the invention, to attain that object, there is proposed a transfer foil of the kind set forth in the opening part of this specification, which includes a base foil which is connected by means of a permanent adhesive to the one surface of a carrier film, at the other surface of which is arranged the decorative layer arrangement which is releasable from the carrier film under the effect of heat, and which on its side remote from the carrier film has the heat-activatable adhesive layer serving for joining to the substrate.
The transfer foil according to the invention therefore differs from per se known hot stamping foils in that, in addition to the carrier or backing film which is provided in known hot stamping foils for stabilisation of the decorative layer arrangement, there is an additional base foil which is joined to the carrier film by means of a permanent adhesive. In that respect the carrier film and the base film are usually joined after manufacture of the actual hot stamping foil. In accordance with the invention therefore there is afforded a transfer foil which is of comparatively, high stability because, instead of the relatively thin carrier film which is hitherto usual in the case of hot stamping foils, there is a combination of base foil and carrier film which enjoys the necessary stability so that the transfer foil can be handled neatly and tidily even without expensive machines. In use, the user lays a transfer foil of that kind with the side on which there is the decorative layer arrangement with the adhesive on the substrate. Then, by the appropriate action of pressure and heat, the decorative layer arrangement is joined to the substrate and then the carrier film jointly with the base foil is pulled off the decorative layer arrangement which remains behind on the substrate. Thus, when using the transfer foil in accordance with the invention, there is the possibility of transferring a very thin decorative layer arrangement which hitherto could only be applied by means of the hot stamping foil procedure to the substrate, for example a document. At the same time however handling of the transfer foil is greatly simplified by virtue of the stability of the combination of base foil and carrier film. In the case of the transfer foil according to the invention the decorative layer arrangement can be designed in the manner which is known from hot stamping foils. In particular there is no need to provide for corresponding stability of the decorative layer arrangement in itself because that decorative layer arrangement is sufficiently stabilised during manufacture by virtue of the presence of the carrier film.
In accordance with the invention therefore there is proposed a transfer foil which, in comparison with known hot stamping foils, enjoys a substantially wider area of use, and which in particular can be securely and reliably processed even by means of very simple apparatuses. Nonetheless the transfer foil in accordance with the invention, in regard to the decorative layer arrangement, enjoys all design configuration options known hitherto from hot stamping foils.
It has proven to be advantageous if the base foil is formed by a paper web which is siliconised on its surface remote from the carrier film an
Dicus Tamra
Hoffmann & Baron , LLP
Kelly Cynthia H
Leonard Kurz GmbH & Co.
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