EP2340532A1

EP2340532A1 - Self-adhesive security label for product authentication

Info

Publication number: EP2340532A1
Application number: EP09756034A
Authority: EP
Inventors: Frédéric VERDUN
Original assignee: Plasto SA
Current assignee: Adhex Technologies SAS
Priority date: 2008-10-17
Filing date: 2009-10-15
Publication date: 2011-07-06
Anticipated expiration: 2029-10-15
Also published as: FR2937456A1; EP2340532B1; WO2010043821A1; FR2937456B1

Abstract

The invention relates to a security label for product authentication, including a single- or multiply transparent substrate (1), coated with a transparent layer of pressure-sensitive adhesive (2), a printing area (3) applied directly onto said adhesive layer (2), the layer (2) being applied to the product (5) to be authenticated. The invention is characterised in that, once adhered to the product to be authenticated, any attempt to remove said label by a manual, mechanical, thermal or chemical means leads to the irreversible destruction of the printing area (3) by the cohesive failure of the adhesive layer (2), wherein the cohesive force is less than the adhesive force.

Description

Self-adhesive security label to authenticate a product

The present invention relates to a security device for the authentication of products, and more specifically to a device consisting of a self-adhesive security label intended to be affixed to products or articles whose origin or membership is to be authenticated, such as motor vehicle registration plates. The label can also be used as a witness for opening or breaking a container whose content integrity is to be protected.

Most of the marketed items or intermediate parts of the industry are identified with self-adhesive labels, glued directly to the item or stuck on the packaging. Simultaneously with the information provided on the nature and characteristics of said article, this label usually indicates the origin and the name of the manufacturer.

However, in certain industrial sectors such as the automotive industry, it is now essential to guarantee the origin of spare parts or identification articles to prevent falsification or counterfeiting.

In addition to the well known methods of securing (for example weakening of one or more layers so that, during an attempt to detach, the different layers separate or tear), one of the proposed solutions consists of self-adhesive labels. adhesives having a plurality of layers printed on at least two sides with different adhesives inks, so that, in an attempt to detach, one of the printed areas is transferred to the back of the upper layer. Such a type of label is described in US4180929.

Similarly, the patent EP0375602 describes a printed product having the configuration of a label, showing a falsification after application to a support, the falsification indication being made by two bonded surfaces, one being a support layer of printed ink which, at any attempt of separation, causes a transfer from one surface to another. For security labels providing proof of the fraudulent opening of a product, patent EP0773889 describes the principle of a closure comprising an adhesive layer applied to a surface, a support on which portions of the adhesive layer stick when said device is applied, and indicating means disposed on the support so as to be between the adhesive layer and the support.

For the protection of a document against forgery, the patent FR2675742 describes a thin transparent protective film comprising a transparent adhesive layer. Between the protective film and the adhesive layer is interposed a continuous or discontinuous printing by means of an ink containing a dye soluble in hydrocarbons. This impression makes it possible to detect any attempt to separate the film by means of a solvent.

Another way to ensure the security function of a label is to include microcapsules in the silicone layer of the protective support in contact with the adhesive layer, as described in the patent application WO9746378. Before bonding to the product to be authenticated, the protective support is pressed against the adhesive layer, thus releasing easily identifiable marker agents on the adhesive layer.

Another type of security tag for authenticating a product is described in US6361079 in the form of an adhesive medium printed on both sides, the upper face having a printing area visible to natural light to inform the consumer. , while the lower adhesive side is printed using a visible ink only with the aid of radiation of specific wavelength.

For the realization of a secure identification label of a motor vehicle, the patent FR2862416 discloses a complex sheet consisting of a transparent adhesive label having a vitrophanie information display area printed under the support and a second zone d specific prints removable and repositionable. The device provides viewing means for attempting to remove the adhesive label at using a control adhesive leaving visible traces or by a weakening support.

However, all of these inventions, having impressions directly attached to the support of the label, provide little protection against forgery despite the complexity of their implementation. Indeed, fraudsters today have advanced mechanical or chemical means to take off and manipulate even very thin films. They can thus take off from the original product to authenticate the label without degrading the characteristics or security devices, then postpone the label on another counterfeit product or falsified, suggesting that this product is original, since it bears a label of security itself authentic.

Document US Pat. No. 4,968,063 also discloses an "overlay", that is to say a film intended to completely cover the support underneath (for example a passport page). The purpose of this overlay is that, if we try to remove it, we must destroy the underlying support. This overlay is bonded with a non-adhesive heat-adhesive adhesive at room temperature (thermally-activatable adhesive of Tg> -15 ° C. and more particularly> 40 ^° C., lines 53 to 60, column 3). The heat-sealing technique requires complex systems and laying conditions (hot laminator) which prevent the use of said overlays on a large scale, and restrict it to the protection of flat documents. On the other hand, according to the indications given in column 4, lines 43-61, in the event of an attempt to tear off the overlay, it is expected that at least part of the image (see also col.3 , lines 1-2), so possibly the whole printed image, is removed at the same time as the overlay. Such a solution, where the entire image carried by the adhesive, would be removed with the overlay, would not be suitable for solving the problem of the invention since it would make the label reusable to authenticate another medium.

The present invention aims to provide a product authentication device that does not have the disadvantages of the prior art, and provides an effective security device against fraud attempts while remaining simple to achieve. The invention achieves its goal thanks to a security label for the authentication of a product intended to be applied on a surface of the product, of the type comprising a transparent support having a first face and a second face, coated on its second surface. a transparent adhesive layer having a first face and a second face, said first face of the adhesive being in contact with said second face of the support, and said second face of the adhesive being intended to adhere to the surface; of the product and comprising first zones on which printing is directly applied and second zones devoid of said printing, said printing being intended to authenticate the product, characterized in that the adhesive is a pressure-sensitive adhesive having a temperature of vitreous transition (Tg) less than -15 ° C and in that the adhesive strength of the label on said product being greater than cohesive layer of the adhesive layer, whereby an attempt to remove the security label from the product leads to a cohesive failure of the adhesive layer, the distribution of said printing areas within said areas; printing-free being such that a cohesive breaking of the adhesive layer leaves at least a part of said impression glued to said product.

The adhesive strength of the label on the product depends not only on the adhesive and the product, but also on the label support. The person skilled in the art knows, by means of simple tests, to experimentally determine if a label satisfies the conditions imposed above: it suffices to observe the behavior of a sample of the device during an adhesive power test, according to one of the many standard methods of measurement, for example when measuring the peel strength at 90 ° according to the standard AFERA 5001 (Association of European Manufacturers of Self Adhesive Tapes), to find out there is cohesive rupture before reaching the force causing the detachment.

In other words, according to the invention, a security impression is made directly on the face of the adhesive layer which is in contact with the product to be authenticated, the adhesive being therefore chosen according to the other elements of the label with a cohesive power lower than its adhesive power in order to ensure that in case of attempted removal (by tearing or peeling or other operation) of said label, the printing area remains totally or at least partially attached to the product and therefore can not be completely removed with the security tag to be reused elsewhere. Thus, according to the invention, the printing zone is destroyed (of the security label itself) partially or totally during any attempt to detach, shear or separate the label of the support of the product to be authenticated. by any manual, mechanical, thermal or chemical means.

Of course, the print area and the print-free area can each be made up of several disjoint regions or surfaces. The printing regions can in particular be constituted by "islands" within a print-free zone.

Advantageously, the 90 ° peel force of the device which reflects the adhesive power is greater than 3 N / cm (standard AFERA 5001). According to the invention, and unlike some known devices, the important thing is not to make a security label that does not come off, but a label that, if it is peeled off, is destroyed at least partially so that it can not be reused to authenticate another product. Naturally, for certain applications, it is preferable to have a higher peel strength, for example at 5 N / cm or even 10 N / cm.

Advantageously, the pressure-sensitive adhesive is chosen from elastomer or acrylic base-pressure-sensitive adhesives, and the person skilled in the art knows how to choose from among those which have an adhesive power corresponding to the desired applications and a lower cohesive power. adhesive power.

According to the invention, because the label is self-adhesive, with a pressure-sensitive adhesive, it is sticky at room temperature, unlike the overlays of US Pat. No. 4,968,063, which requires, on the one hand, laying and secondly to be non-sticky at room temperature to be manipulable when it comes to cover a whole document. According to the invention, because it is a simple label, the problem of manipulation does not does not arise in the same terms, and no means of activation of the adhesive is required.

The label of the invention comprises, before use on the product to be identified, a non-stick protector disposed on the adhesive layer which has the printing zone.

Other characteristics and advantages of the invention will emerge on reading the following description of an embodiment, with reference to the appended drawings in which:

- Figure 1 is a schematic sectional view of a label according to the invention presented before use on its non-stick protector.

- Figure 2 is a schematic sectional view of a label according to the invention applied to the bonding substrate of the product to be authenticated.

- Figures 3 and 4 are schematic sectional views of the principle of application of the invention during an attempt to detach the label with a sharp object.

- Figure 5 is a variant of Figure 4 illustrating the result of an attempt to detach the label by a non-rectilinear cut with a sharp object.

- Figures 6 and 7 are schematic sectional views of the principle of application of the invention during an attempt to detach the label with a jet of liquid or gas at high pressure.

- Figures 8 and 9 are schematic sectional views of the principle of application of the invention during an attempt to detach the label with a solvent.

The label according to the invention and shown in FIG. 1 comprises a transparent support 1 with two faces Ia and Ib, whose lower face Ib is coated with a transparent layer 2 of pressure sensitive adhesive having two faces 2a, 2b, the latter being intended to be bonded by contact with the surface of a product to be authenticated. The thickness of the adhesive layer 2 is preferably between 10 μm and 200 μm. Authentication printing 3 is applied directly to the face 2b of the adhesive layer 2, in a printed area of said surface. The thickness of the printing 3 is, for example, from 1 μm to 50 μm. The distribution between the printed area and the unprinted complementary area is chosen to allow on the one hand the necessary adhesion to the surface of the product, in the period of use of the label, and on the other hand that the printed area is carried at least partially during an attempt to tear the label as will be seen later; it is indeed the presence of the entire print 3 visible through the layers 1 and 2 that guarantees according to the invention the authenticity of the product, while the observation of a reduced print only to a part from what it must be translated an attempt at fraud. In practice, it is sufficient for the dimensions of each individual surface of the printed area to be rather small and / or narrow relative to the adjacent unprinted area to ensure that it will not be possible to completely remove the printed areas in the event of a problem. tearing of the label, insofar as at least a portion of the printed areas will remain attached to a sticky area that remains attached to the product after cohesive failure of the adhesive layer.

A non-stick protector 4 (for example a paper or a silicone film of standard type) is applied to the adhesive layer 2 after printing of said adhesive layer 2 by ink or varnish 3, while waiting for to be removed for the use of the label on the surface of the product to be authenticated represented here by its single bonding substrate (see Figure 2).

The support 1 is a transparent film based on cellulose or polymers, for example: tracing paper, polyethylene, polypropylene, coextruded polyolefin, polyester, PVC, polyurethane, polystyrene, polycarbonate, polyamide, etc. Its thickness is, for example, from 10 μm to 5 mm. The support 1 may consist of one or more transparent layers, partially or totally adhesive on each other, possibly separated by partial or total prints or varnishes. This layer or layers may previously include authentication elements, such as: iridescent or fluorescent elements printed or included in the support, thermal or chemical reagent, incorporation of holographic image by hot or cold foil stamping using a security ink, such as for example a color-changing ink under the effect of heat or the angle of vision, optically variable impressions (OVI) with or without filters, etc.

Advantageously, the support 1 may also contain a prior embrittlement for example in the form of cuts or pre-cuts in its thickness in order to weaken it under the effect of mechanical traction.

The adhesive layer 2 coated on the support 1 is transparent.

The stack of the support 1 and the adhesive layer 2 is sufficiently transparent so as to allow visualization, with the eye or with the aid of optical means (magnifying glass or microscope, ...), the presence of the printing 3 through this stack of the support 1 and the adhesive layer 2.

The adhesive layer 2 coated on the support 1 is composed of a pressure-sensitive adhesive of the standard type, acrylic base or elastomer. Preferably, the composition of the adhesive has a low or medium cohesion to facilitate its disintegration in thickness under the effect of a mechanical or chemical stress. The adhesive is characterized in that it has a Tg (measured by differential scanning calorimetry DSC) lower than -15 ° C. The composition of the adhesive is such that it allows the fixing of the label of the invention on the product to be authenticated for a long time, for the entire life of said product 5. According to an essential characteristic of the invention the adhesion strength of the adhesive layer 2 and the printing 3 on the bonding substrate of the product to be authenticated (and possibly the adhesive force of the adhesive layer 2 on the support 1) is greater than the force needed to generate a break cohesion of the adhesive layer 2. Thus, during a mechanical or chemical stress of the label according to the invention applied to the bonding substrate of the product to be authenticated, there is a cohesive failure of the adhesive layer. adhesive 2: a part of the adhesive layer 2 and the printing 3 remains attached to the support 1, the other to the bonding substrate 5 of the product to be authenticated, as shown in FIG. choose a suitable adhesive according to this objective, as will be seen later by examples.

The printing 3, applied directly in mirror (vitrophanie) on the adhesive layer 2, can be achieved by all the conventional printing technologies called by contact with the adhesive layer 2, for example: flexography, typography, etc., or by unconventional printing technologies said to be non-contact with the adhesive layer 2, for example: digital printing, laser, inkjet, etc.

The ink or varnish used to carry out the printing 3 may be a so-called standard ink or varnish or a security ink or varnish comprising, for example, iridescent, luminescent, photo-luminescent, phosphorescent or fluorescent elements, tracers or chemical or thermal reagents, elements detectable by filter or radiation, optically variable elements (OVI) with or without filters, etc. It may also be inks or varnishes with color modification under the action of radiation (eg a laser beam).

Printing 3 applied directly to the adhesive layer 2 can also reproduce unique and non-reproducible alphanumeric data (for example random prints, coded numbering, guilloche, microimpressions, hidden words or coded words, etc.) by means of printing technologies. printing and inks mentioned above.

The impression 3 remains visible or at least detectable throughout the lifetime of the product on its bonding substrate 5. The nature and the physico-chemical characteristics of the support 1, the adhesive layer 2, the printing 3 are chosen by those skilled in the art as a function of the external stresses and stresses (for example ultraviolet-type radiation resistance ( UV), temperature, humidity, gaseous environment, etc.) to which the invention will be subjected throughout its lifetime. In particular, the presence and visualization of the entire print 3 through the stack of the support 1 and the adhesive layer 2 will not be altered by these external stresses and stresses.

FIGS. 3, 4 and 5 show the principle of operation of said label during an attempt to detach with the aid of a sharp cutting object 6, of the "cutter" or razor blade type, the cutting being possible uniformly and substantially rectilinearly (Figure 4) or not (Figure 5). This attempt to detach can be facilitated by the cross-use of a thermal means for example a hair dryer or a manual means (for example a fingernail). The adhesive layer 2 is cut partially in slice in its thickness. Part of the adhesive mass remains on the support of the product 5 to be authenticated, another part of the adhesive mass remaining on the support 1 of the label. In one case, shown in FIG. 4, the whole of the label is separated clearly at the level of the adhesive mass 2, and all the impressions 3 remain on the authentic product 5. In another case, as represented in FIG. 5, the cut is irregular and a part of the prints is removed at the same time as the support 1 of the label, but a remaining part remains bound to adhesive parts glued to the authentic product 5, so that the prints 3 that could to be removed with the support 1 of the label are incomplete or altered.

Thus, during an attempt to detach, even if the support 1 of the label remains intact despite its weakening elements constituted by the internal cuts, the impression 3 made directly on the adhesive layer 2 can not be recovered. in its entirety with the support 1 of the label, which will prohibit the reuse of said label with the initial printing 3. Indeed, in case of reuse, the absence (Figure 4) or the alteration (Figure 5) of the printing 3 performed on the adhesive layer 2 can be easily put visible with the naked eye or with an optical instrument (magnifying glass or microscope for example).

Figures 6 and 7 show the principle of operation of said label during an attempt to detach with a jet of liquid or gas at high pressure (eg high pressure cleaner 7). The adhesive layer 2 and the printing 3 that it comprises will gradually cut or disintegrate. There will therefore be an irreversible alteration of this printing 3 which can not be recovered in full with the support 1 of the label, which will prohibit its reuse. Indeed, as in the previous case, in case of reuse, the absence or the alteration of this impression 3 made on the adhesive layer 2 can be easily highlighted with the naked eye or the help of an optical instrument.

Figures 8 and 9 show the principle of operation of said label during an attempt to detach with solvents (eg acetone, alcohol, heptane, etc.). Under the action of these solvents, the adhesive layer 2 and the printing 3 that it comprises will gradually dissolve, dilute or degrade. There will therefore be an irreversible alteration of this impression 3 as in the previous cases.

We will now describe more specific examples of manufacture of a label according to the invention.

In the case where the product bonding substrate 5 is a retro-reflective film of the 3M supplier, reference 4720, or of the NCI supplier, reference 4412, or a polymethyl methacrylate (PMMA) plate, the support 1 may be a film transparent of polyester nature; it will be possible to use the reference Lumirror 60.01 in thickness 36 μm or 50 μm of the company Toray. For the production of the adhesive layer 2, it is advantageous to use either 40 to 55 g / m 2 of alkyl acrylate copolymers in the solvent phase of the following references: Polytex SP 2000 from AV-Chemie, Durotack 3803954 from National Starch company, Gelva 2495 of the company Cytex. The adhesive products used, based on alkyl polyacrylates, have a glass transition temperature Tg lower than -15 ^° C., but can however, be printed at room temperature. The adhesion measurements will be carried out after an accelerated aging cycle (the device bonded to the bonding substrates of the product 5 mentioned above undergoes the following climatic cycle: 16 hours at 40 ^° C. and 95% relative humidity and then 3 ^° C. hours at -20 ^° C. and then 6 hours at 85 ^° C.); the adhesion force at 90 ° (measured according to the AFERA 5001 method) of the support 1, the adhesive layer 2 made with one of these adhesives to the indicated weights and printing 3 on the bonding substrates of the product 5 is greater than or equal to 3 N / cm with cohesive failure of these adhesive masses during the measurement.

Depending on the nature of the adhesive layer 2 (see the example above) the surface of the printing 3 will be adjusted on the adhesive layer so as not to degrade the adhesive performance of this adhesive layer too much. adhesive 2 respecting the criterion indicated above. In practice, the proportion of the adhesive layer 2 covered by the printing 3 may be for example between 0.5% and 20% of the total area. It is preferable to print patterns with fine lines and separated from the guilloche type with a 0.2 mm width of the line, spaced apart by 2 mm, representing approximately 9% of the surface of the adhesive layer 2.

In this example, the printing 3 is performed on a rotating coil-coil flexographic printing machine equipped in line with a delamination / re-rolling system with ultra-violet radiation drying: the support stack is unrolled. 1, adhesive layer 2, silicone protector 4 at the machine head. The support 1 and the adhesive layer 2 of the silicone protector 4 are delaminated on the delamination station. The support 1 and the adhesive layer 2 run through a circuit during which the printing plate and the ink on the surface of said plate are rolled onto the adhesive layer 2. The ink refers to the layer of adhesive adhesive 2 and is dried after passing through an ultra violet radiation oven. It will be possible, for example, to use the Sigoc UFZ80114 Flexocure ink from Xsys or the Solarflex Lux Slux 46 ink from Sun Chemical. The stack of the support 1, the adhesive layer 2 and the printing 3 thus produced is re-complexed on the original silicone protector 4 which followed during this operation a parallel circuit in the printing machine. The label according to the invention has many applications in industrial, commercial and consumer activities, and as examples, the following applications may be mentioned:

- security label for the traceability and authentication of license plates;

- security label for the traceability and authentication of motor vehicles; - security label for the traceability and authentication of equipment or spare parts of motor vehicles;

- security label for the traceability and authentication of industrial products;

- witness label for the opening of any product packaging or document closure element (boxes, flasks, sachets, envelopes, etc.)

The use of the label according to the invention can be extended to many fields, such as for example: aeronautics, the food industry, cosmetics, electronics, household appliances, building, DIY, health, etc.

Claims

1. Security label for the authentication of a product (5) intended to be applied on a surface of the product (5), of the type comprising a transparent support (1) comprising a first face (la) and a second face (Ib), coated on its second face (Ib) with a transparent layer of adhesive (2) comprising a first face (2a) and a second face (2b), said first face (2a) of the adhesive being in contact with said second face (Ib) of the support (1), and said second face (2b) of the adhesive (2) being intended to adhere to the surface of the product (5) and comprising first zones on which is directly applied an impression (3) and second zones devoid of said printing (3), said printing (3) being intended to authenticate the product (5), characterized in that the adhesive (2) is a pressure-sensitive adhesive exhibiting a glass transition temperature (Tg) below -15 ^° C. and in that the adhesive power of the label on said product (5) is greater than the cohesive strength of the adhesive layer (2), whereby an attempt to remove the security label from the product (5) leads to a cohesive failure of the adhesive layer (2), the distribution of printed areas and non-printing areas being such that a cohesive failure of the adhesive layer leaves at least a part of said printing (3) bonded to said product (5) .

2. Label according to claim 1, characterized in that the adhesive power of the device results in a 90 ° peel force of the label on said product (5) greater than 3 N / cm.

3. Label according to any one of claims 1 or 2, characterized in that the adhesive (2) is deposited in a thickness between 10 .mu.m to 200 microns.

4. Label according to any one of claims 1 to 3, characterized in that the thickness of the printing (3) is 1 micron to 50 microns.