Stock material or miscellaneous articles – Layer or component removable to expose adhesive
Reexamination Certificate
1998-10-15
2001-10-30
Ahmad, Nasser (Department: 1772)
Stock material or miscellaneous articles
Layer or component removable to expose adhesive
C283S060100, C283S081000, C283S101000, C283S103000, C283S105000, C428S040200, C428S204000, C428S206000, C428S207000, C428S352000, C428S423100
Reexamination Certificate
active
06309724
ABSTRACT:
Technical labels are employed in numerous sectors for high-grade applications—for instance, as model identification plates for vehicles, machines, electrical and electronic appliances, as control labels for process sequences, and as badges of guarantee and testing. In numerous instances these applications automatically entail the need for a greater or lesser degree of security against counterfeiting. This counterfeiting security applies primarily for the period of application and for the entire duration of use on the part to be labelled: removal or manipulation, if possible at all, should entail destruction or visible, irreversible alteration. In particularly sensitive fields of application there must be a security stage for the production of the labels as well: if the acquisition and marking of such labels were too easy, and if imitations were produced, unauthorized persons would be given the possibility of improperly trafficking in the articles concerned.
For the rational and variable production of high-grade labels, especially in technoindustrial applications, the laser marking of suitable base material is becoming increasingly more established. DE U81 30 861.2 describes a multilayer label in which a top layer differing in colour is removed by the laser beam and, as a result, the contrast in colour with the adjacent layer permits inscriptions of high quality and legibility. Such an inscription constitutes a type of gravure, but removes the possibilities for manipulation associated with traditional printing with inks. DE U81 30 861.2 entails the label film being rendered so brittle, by means of the raw materials employed and the production process, that it is impossible to remove the bonded labels from their substrate without destroying them.
An additional security stage is described in the single-layer laser label of DE U94 21 868: here, in addition to the advantageous properties of DE U81 30 861.2, the inscription is brought about not by gravure in the top layer but by a change in colour in the polymer layer itself, thereby very substantially preventing subsequent manipulation at the level of the inscriptions.
Consequently, the only potential missing link in the security chain is that such single-layer and multilayer labels are freely available for laser inscription—for goods of appropriately high value, therefore, the acquisition of the labels and their inscription, even with expensive laser equipment, might be regarded as possible and rewarding.
In order to close the chain, it was the aim of the development to configure the material from which the labels are made in such a way, for their subsequent inscription, that such material can be identified at any time, with little effort and no destruction, as authentic, original material. For the laser labels which have already been specified, subsequent identification, although possible in principle, is nevertheless bound up with unacceptable analytical effort and is destructive.
Diverse techniques of ensuring security against counterfeiting are known for particularly security-relevant products, such as bank notes, cheques, cheque cards and personal ID cards, inter alia. In addition to water marks, printing with intricate patterns, and application of holograms, “invisible” markings are also occasionally employed.
JP 08/328474 describes a textile clothing label which is printed on its top face with a transparent, fluorescent ink, it being intended for the woven design and the printed image to be approximately identical in overlap. A similar surface printing with UV-active, photochromic inks is described in WO 88/01288; in order to protect the chemicals, however, this ink layer requires an additional layer for protection against oxygen and water.
In FR 2734655, a security marking on cheques is achieved in that, in part, the printing under a layer which is permeable only to IR is invisible in the visible wavelength range but can be read/identified mechanically with special IR light.
EP 727316 achieves hidden security against counterfeiting by providing, in an extra layer, especially on paper, two reactive components which give a colour reaction under pressure—this reaction, however, is irreversible.
The use of electroconductive and/or magnetic inks for surface printing is described in JP 08/054825 and CN 1088239. For label applications on complex metal parts, such as vehicle and machine components, for example, the fitness of such systems for use is extremely limited.
The ink ribbons with fluorescent particles described in JP 07/164 760, which can be excited by IR, are transferred by means of heat, with thermal transfer printers. Although it is true that the prints constitute a hidden sign of originality, the printing is applied superficially and can be altered or removed with solvents, with heat or else mechanically.
DE 4231800 describes labels which for security against counterfeiting leave irremovable traces on the bonding substrates by means of sublimation inks or corrosive substances—in order to identify the traces, however, it is first necessary to remove the label, which is in many cases undesirable if not impossible.
For high security papers such as passports, shares, bank notes, etc., EP 453131 describes the incorporation into an interlayer between two permanently bonded plies of paper, along with the laminating adhesive, of fluorescent—especially UV-fluorescent—indicators which are detectable only on transmission of light of appropriate wavelength through the laminate, but not by reflection under incident light. This system is unsuited to applications where transmission of light through the bonded label is impossible, and for the totally opaque laser labels.
All of these methods are applied superficially or are effective superficially and are therefore useful only to an extremely limited extent if at all for the known laser labels, since in this case the surface of high optical quality and extreme resistance used, for example, for model identification plate applications would be altered and impaired. Such a modification would be particularly disruptive to the two-layer labels with high-gloss black top layer and white base layer that may be regarded as the technical standard for identification plates. In addition, the means of security against counterfeiting that are known from the prior art, which are applied superficially and subsequently, carry with them the potential for manipulation to be carried out mechanically or using heat, chemicals, etc.
The object of the present invention was therefore to incorporate a substantially “invisible” additional security stage into the material from which the labels are made in order that originality can be proved rapidly, nondestructively and with a minimum of effort. This invention has been realized by way of example for the laser-markable labels but can readily be transferred by the skilled worker to similar problem cases, such as printed labels, self-adhesive tapes and the like.
This object is achieved by a laser label as is characterized in more detail in the claims.
This facility proves to be both a technically favourable and an inexpensive solution, and has the advantage over the prior art that neither the high-value surface constitution of the top layer nor the top layer itself is altered; minor interventions are made only in the base layer. Consequently, neither the overall visual impression nor the top layer, which is critical for mechanical, chemical and physical resistance of the label, is altered. In addition, a customer-specific mark is easy to produce, thereby placing an additional hurdle in the way of the unauthorized acquisition and use of labels.
In the case of the two-layer and multilayer labels it is therefore possible to incorporate an appropriate additive into the base layer, which is the layer critical for the text. The top layer thereof therefore remains unchanged for, for example, the high-gloss identification plates; not until the laser engraving stage is the base layer partially exposed at the areas of the inscription. If the base layer—which in this case
Koops Arne
Kulper Klaus
Ahmad Nasser
Beiersdorf AG
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