Stock material or miscellaneous articles – Layer or component removable to expose adhesive – Metal containing
Reexamination Certificate
2000-09-15
2003-09-30
Pyon, Harold (Department: 1772)
Stock material or miscellaneous articles
Layer or component removable to expose adhesive
Metal containing
C428S156000, C428S166000, C428S167000, C428S172000, C428S209000, C428S202000, C428S913000, C428S040100, C029S017100, C029S018100
Reexamination Certificate
active
06627286
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention concerns a stamping foil, in particular a hot stamping foil, comprising a carrier film on which there is releasably arranged a decoration layer which can be transferred on to a substrate by means of heat and/or pressure and which adhesively sticks to the substrate. The invention also concerns production processes for stamping foils of that kind.
Stamping or embossing foils of that kind are used for the decoration of the most widely varying substrates, in which respect the decoration layer can be of various configurations. Usually however the decoration layer of stamping foils comprises at least one protective lacquer layer portion which, after the decoration layer is applied to the substrate, forms the free outward side, as well as further layer portions forming the actual decoration elements. In general the layer portion of the decoration layer, which is furthest away from the carrier film, forms an adhesive layer portion, by means of which the decoration layer then adheres to the substrate. Stamping or embossing foils of quite special decoration have also been used for some years to a quite considerable extent in order to provide items of value or value documents, for example banknotes, cheques, value papers such as securities and bonds, credit cards etc, with an additional security feature which can only be forged with difficulty. For security purposes, hot stamping foils provided with so-called ‘OVDs’ (Optically Variable Devices) are used to a quite considerable extent. For that purpose the decoration layer of the stamping foil usually has a generally thermoplastically deformable layer portion, into which then a structure having an optical-diffraction effect, for example a suitable grating structure, is replicated in the course of production of the stamping foil. In order to make a structure with an optical-diffraction effect of that kind as clearly visible as possible, the usual practice in a large number of cases is that the suitably structured surface of the deformable layer portion is provided with a reflection layer portion which is distinguished in that its refractive index is substantially different from that of the layer portion of the decoration layer, against which the reflection layer bears. In most cases a metal layer portion which is generally applied by vapour deposition is used as the reflection layer portion.
Stamping or embossing foils of that kind are described in DE 44 23 291 A1 as state of the art.
SUMMARY OF THE INVENTION
In particular for security uses it may now be desirable for a security element formed by the decoration layer of a stamping foil to be also overprinted after it has been applied to the substrate, for example a banknote, in order in that way to make forgery thereof even more difficult. Now, in principle there are two possible ways of transferring the decoration layer from the carrier film of the stamping foil on to the substrate, more specifically, either transfer of the decoration layer in strip form by means of a suitable roller or the like, or patch-wise application of suitable regions of the decoration layer to the substrate. Hitherto, it was generally assumed that at least one layer portion of the decoration layer of the stamping foil is present over a large surface area, in which case the corresponding spot or patch is produced on the substrate by a procedure whereby the decoration layer is stamped on to the substrate by means of a suitably shaped stamping punch. With that method of stamping or transferring the decoration layer from the carrier film of the stamping foil on to the substrate however, the decoration layer of the stamping foil is generally torn along the edge of the patch to be transferred, from the regions of the decoration layer which remain on the carrier film and which are pulled off the substrate together with the carrier film after the stamping or embossing operation. A corresponding consideration applies in the situation where, when implementing the transfer operation by means of a roller, the track produced by the roller is of narrower width than the strip of decoration layer present on the carrier film. When regions of the decoration layer are torn away or torn out during the stamping transfer operation, small particles which come off in splinters, so-called flakes, very frequently occur, and in the subsequent printing operation, under some circumstances they can cause quite considerable problems and difficulties. In that respect, it is to be borne in mind that it is precisely in the case of security elements that the decoration layer is metallised at least in a region-wise manner. The flakes cause problems and difficulties in particular for the reason that they result in contamination of the printing machine and thus in untidy and blurred printing. The printing which is subsequently applied to a security element is in fact also frequently very finely structured. Suitable cleaning of the machine in which under some circumstances the stamping operation on the one hand and the over-printing operation on the other hand are effected in succession, between the stamping operation and the printing operation, is not possible, at least at reasonable cost.
Therefore the aim of the invention is to propose a stamping foil and a process for the production thereof, which make it possible to apply a suitable decoration layer to a substrate, in the form of individual patches, without the fear that troublesome flake formation occurs. At the same time, the invention seeks to provide that a suitable stamping foil can be produced with a very good degree of accuracy and register relationship of the various layer portions, which are possibly provided, of the decoration layer.
To attain that object, in accordance with the invention, there is proposed a stamping foil of the kind set forth in the opening part of this specification, in which the decoration layer is divided into individual patches which are completely separate from each other and which are individually transferable on to a substrate, wherein provided around each of the individual patches on the carrier film is a respective free space, in particularly simple fashion in the form of a border or edging, of a width of at least 1 mm, preferably at least 2 mm, in which the decoration layer material initially present in the intermediate spaces is subsequently removed so that the carrier film is exposed there.
In accordance with the invention a stamping foil of that kind is desirably produced in such a way that the materials forming the decoration layer are applied to the carrier film in a manner known per se from the production of stamping foils, in such a fashion that the decoration layer projects everywhere beyond the edge of the transferable patches to be formed, and that, to form the free spaces, decoration layer material is subsequently removed along the entire edge of each individual patch.
The stamping foil according to the invention or the stamping foil produced by the process in accordance with the invention is therefore distinguished in that the precise delimitation and definition of the patches to be transferred on to the substrate is achieved by subsequent removal of the regions of the decoration layer, which extend beyond the desired patch region. That has in particular the advantage that the stamping foil, as it is used for transfer of the decoration layer patches on to the substrate, has suitable decoration layer portions only where transfer is actually to be effected. Therefore, when the corresponding patches of the decoration layer are transferred on to the substrate, that no longer involves separating the decoration layer out of a larger surface portion. Consequently, there is no possibility of troublesome flake formation taking place. Even if flakes should occur in the subsequent operation of removing the decoration layer, in the region of the free spaces, it is readily possible, for example by means of a suction removal device which is known per se for installations for processing by means of laser radiation, to r
Egan Brian P.
Hoffmann & Baron , LLP
Leonhard Kurz GmbH & Co.
Pyon Harold
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