Method for manufacturing a secure document with a mirror effect

Abstract

Method for manufacturing a secure document with a mirror effect. The invention relates to a method for manufacturing a secure document with a smooth, mirror-like appearance, unlike secure documents obtained using known prior art manufacturing processes. Such a manufacturing process aims to improve the aesthetics and distinctiveness of such a secure document. Figure for the abstract: Fig. 1.

Description

Title of the invention: Method for manufacturing a secure document exhibiting a mirror effect technical field

[0001] This application falls within the general field of secure documents. It relates more particularly to a method for manufacturing a secure document exhibiting a mirror effect, as well as to a secure document obtained by means of such a manufacturing method.

[0002] The invention finds a particularly advantageous application in the field of secure documents in the form of cards made of polymer materials such as payment cards or identity cards.

[0003] The invention may also be of interest in the field of business cards, loyalty cards or gift cards in which the aesthetic aspect of these objects is particularly differentiating. Previous technique

[0004] Typically, a secure document, such as a bank card, consists of a plurality of layers stacked one on top of the other. These layers, which can for example be made of different polymer materials, such as PVC (or polyvinyl chloride), PET (or polyethylene terephthalate) or PC (or polycarbonate), allow, in particular, for the personalization and authentication of the secure document.

[0005] In order to modify the appearance of these secure documents to offer a distinctive aesthetic, it is known to use a metallic layer intended to create a mirror effect.

[0006] Figure 1 represents such a secure document 10, front view. The secure document 10 comprises, on a first surface Fl, at least one area exhibiting a ZPEM mirror effect.

[0007] By way of example, the area exhibiting a ZPEM mirror effect can cover the entire first surface Fl of the secure document 10. Alternatively, the area exhibiting a ZPEM mirror effect can simply cover a limited area of ​​the first surface Fl of the secure document 10 as is the case in the representation given in [Fig.1].

[0008] Since the secure document 10 is in a substantially rectangular shape, a cutting plane II chosen parallel to a width of the secure document 10 is also shown in [Fig.1].

[0009] In general, the secure document 10 comprises a plurality of layers visible on [Fig.2] which represents the secure document 10 according to the cutting plane II introduced with reference to [Fig.1].

[0010] More specifically, the secure document 10 includes a substrate 11. In certain situations, this substrate 11 may include a near-field communication antenna such as an NFC (Near Field Communication) antenna. This is particularly the case when the secure document 10 is a payment card or a transport ticket.

[0011] A first printable layer 12 is placed on a first surface End of the substrate 11.

[0012] A metallic layer 13 covers at least a part of a surface Fi2 of the printable layer 12. Such a metallic layer 13 is, for example, deposited by vaporizing metallic particles onto a part of the surface Fi2 of the printable layer 12. The metallic layer 13 can also be, in another example, a thin sheet of metal deposited on the surface F[2 of the printable layer 12.

[0013] Distinctive designs, such as visuals, logos, trade names, trademarks, slogans, etc., can be printed on surface Fi2 of the printable layer 12 as well as on a surface Fn of the metallic layer 13.

[0014] In order to ensure the protection of the secure document 10 against any attempt at fraud and / or data theft or more simply to protect the secure document 10 against external aggressions which could alter its appearance, the surface Fi2 of the printable layer 12 and the surface Fn of the metallic layer 13 are covered with a layer 14 of transparent polymer material.

[0015] A second printable layer 12' is disposed on a second surface F2n of the substrate 11. Such a printable layer 12' can also carry information relating to the holder of the secure document 10.

[0016] In order to ensure the protection of the secure document 10, the surface Fi2- of the printable layer 12' is also covered with a layer 14' of transparent polymer material.

[0017] Layers 11, 12, 13, 14, 12' and 14' are then hot laminated, thus sealing the secure document 10 and its contents.

[0018] Since the polymer material constituting layers 14 and 14' consists of monomer chains, the homogeneity of the polymer material can change following exposure to heat.

[0019] Indeed, during the hot rolling stage leading to the production of the secure document 10, the monomer chains constituting the polymer material begin to move under the effect of heat, which leads to displacements of material within layers 14 and 14'. When this heat exceeds the glass transition temperature of the polymer material, the movements of the monomer chains reach such an amplitude that in certain areas of layers 14 and 14' having more or less large surfaces, variations in the thickness of these layers 14 and 14' are created.

[0020] When the polymer material cools after the rolling step, the metal layer 13 takes the shape of the surface of the layer 14 with which it is in contact, thus generating the mirror effect. However, since layer 14 has variations in thickness, the surface in contact with the metal layer 13 exhibits imperfections, leading to an "orange peel" effect. In other words, instead of obtaining a smooth mirror, an unsightly visual appearance is obtained, as shown in [Fig. 3], where the surface of the metal layer visible through layer 14 displays undulations.

[0021] There is therefore a need to propose a method for manufacturing secure documents with a mirror effect that reduces the "orange peel" effect. Description of the invention

[0022] The present invention aims to remedy all or part of the disadvantages of the prior art, in particular those set out above, by proposing a solution which makes it possible to obtain a mirror with a smooth appearance.

[0023] To this end, and according to a first aspect, the invention relates to a method for manufacturing a secure document exhibiting a mirror effect, said secure document comprising at least: - a first layer, one surface of which is placed on a substrate and a second surface is at least partially covered by a metallic layer; - a second transparent polymer layer covering, at least partially, the second surface of the first layer and the metallic layer; said manufacturing process comprising at least one hot lamination step during which the substrate, the first layer and the second layer are assembled to form the secure document, the first layer and the second layer being bonded together by means of an adhesive material.

[0024] Such a manufacturing process is particular in that: - the rolling temperature is less than or equal to the glass transition temperature of the transparent polymer constituting the second layer; - the average surface roughness of the adhesive material is less than 0.05 micrometers (pm); and - the average surface roughness of the surface of the second layer in contact with the metallic layer is also less than 0.05 pm.

[0025] By not exceeding the glass transition temperature of the transparent polymer during the hot rolling step, material movement within the transparent polymer layer is limited. Thus, unlike what occurs in the prior art, the material distribution remains homogeneous throughout the polymer layer. Consequently, the layer does not exhibit any thickness variations.

[0026] By using a sheet of transparent polymer material having a very low average surface roughness, it is ensured that the surface of the polymer material layer in contact with the metal layer is as flat and smooth as possible.

[0027] In order to preserve the smooth and flat appearance of this contact surface, the inventors of the present method propose using an adhesive material that also has a very low average surface roughness. Thus, when the adhesive material melts under the effect of heat, it spreads homogeneously over the surface of the metal layer, without creating any variations in thickness.

[0028] Therefore, when the polymer material cools after the rolling step, the metallic layer which takes the shape of the surface of the polymer material layer, has a smooth surface with few or no imperfections.

[0029] In particular embodiments, the transparent polymer material constituting the second layer belongs to the group comprising: - polycarbonate, - polyamide, - polyvinyl chloride, - polyethylene terephthalate.

[0030] In particular embodiments, the substrate includes near-field communication means.

[0031] This is particularly the case when the secure document is a payment card or a transport card.

[0032] In particular embodiments, the adhesive material is an ink.

[0033] The adhesive material then fulfills a printable function of the secure document. This avoids adding extra material between the polymer material layer and the metal layer which could contribute to the appearance of an "orange peel" effect when the polymer material layer cools.

[0034] In particular embodiments, the ink is a transparent ink.

[0035] In particular embodiments, the adhesive material is a transparent resin.

[0036] In particular embodiments, the manufacturing process includes, prior to the lamination step, a step of obtaining said second layer by laminating the transparent polymer between two laminating plates whose surfaces in contact with the polymer material have an average surface roughness of less than 0.05 pm.

[0037] Finally, according to a second aspect, the invention relates to a secure document exhibiting a mirror effect obtained by means of the manufacturing process according to any one of the implementations described above. Brief description of the drawings

[0038] Other features and advantages of the present invention will become apparent from the description below, with reference to the accompanying drawings, which illustrate an example of an embodiment without being limiting in any way. In the figures:

[0039] [Fig.1] [Fig.1] represents a front view of a secure document having on a first surface, at least one area exhibiting a mirror effect;

[0040] [Fig.2] the [Fig.2] the secure document of the [Fig.1] according to the cutting plan II introduced with reference to the latter;

[0041] [Fig.3] [Fig.3] represents a secure document obtained by means of a manufacturing process conforming to state-of-the-art techniques, the secure document thus obtained has a mirror effect of "orange peel" appearance;

[0042] [Fig.4] [Fig.4] represents a secure document obtained by means of the manufacturing process of the invention, the secure document thus obtained has a smooth mirror effect. Description of the implementation methods

[0043] The present invention proposes a method for manufacturing a secure document with a smooth, mirror-like appearance, unlike secure documents obtained using known prior art manufacturing processes. This contributes to improving the aesthetics and distinctiveness of such a secure document.

[0044] For the remainder of the description, the secure document 10 is considered, without limitation, to be a payment card as described above with reference to [Fig.1] and [Fig.2].

[0045] In order to obtain a smooth mirror-like appearance and thus reduce the "orange peel" appearance, the inventors of the present solution propose to apply several rules during the manufacture of this secure document 10 which will be described in more detail later in this document.

[0046] As already explained with reference to Figures 1 and 2, the secure document 10 comprises: - a substrate 11, which may include in other implementations, a near-field communication antenna such as an antenna; - a first printable layer 12 placed on the first surface End of substrate 11, - a metallic layer 13 covering, at least a part, a surface Fi2 of the printable layer 12; - a layer 14 of transparent polymer material covering, at least in part, the surface Fi2 of the printable layer 12 and the surface Fn of the metallic layer 13; - a second printable layer 12' arranged on a second surface F2n of the substrate 11; and - a 14' layer of transparent polymer material covering, at least in part, the Fi2- surface of the printable 12' layer.

[0047] In order to obtain the smoothest possible mirror effect, a first rule consists of depositing a layer 14 of polymer material whose surface in contact with the surface Fb of the printable layer 12 and the surface Fn of the metallic layer 13 has an average surface roughness less than or equal to 0.05 micrometers (pm).

[0048] By depositing a layer 14 having a very low average surface roughness, we ensure that the surface of the layer 12 in contact with the surface Fb of the printable layer 12 and the surface Fn of the metallic layer 13 is as flat and smooth as possible.

[0049] A second rule is to choose an adhesive material that also has an average surface roughness of less than or equal to 0.05 pm.

[0050] By selecting an adhesive material with such a property, it is helpful to preserve the smooth and flat appearance of the Fn surface of the metal layer 13. Thus, when the adhesive material melts under the effect of heat during the lamination step, it spreads homogeneously over the Fn surface of the metal layer 13 and does not create variations in thickness that could cause an "orange peel" effect.

[0051] By way of example, the adhesive material may be an ink. It then fulfills a printable function of the secure document 10. Such an ink may, in some cases, be a transparent ink.

[0052] In other embodiments, the adhesive material is a transparent resin. Such a transparent resin may be, for example, a polyvinyl chloride copolymer or vinyl acetate. It should be noted that other types of resin transparent materials can be used as long as they have an average surface roughness of less than or equal to 0.05 pm.

[0053] Finally, a third rule is not to heat the rolling plates beyond the glass transition temperature of the polymer material constituting layer 14.

[0054] Indeed, as already mentioned above in this document, the polymer material constituting layers 14 and 14' being made up of chains of monomers, the homogeneity of this polymer material can evolve following exposure to heat.

[0055] By not exceeding the glass transition temperature of the transparent polymer during the hot rolling step, material movements within the transparent polymer layer are limited, which reduces the risk of variations in thickness of the polymer material appearing which could cause an "orange peel" effect.

[0056] By using a sheet of transparent polymer material having a very low average surface roughness, it is ensured that the surface of layer 14 in contact with the surface Fi2 of the printable layer 12 and the surface Fn of the metallic layer 13 is as flat and smooth as possible.

[0057] Thus, when the polymer material cools after the rolling step, the metal layer 13 takes the shape of the surface of the layer 14 with which it is in contact, and consequently presents a smooth surface with few or no imperfections.

[0058] The transparent polymer material constituting layer 14 can be polycarbonate, polyamide, polyvinyl chloride or polyethylene terephthalate.

[0059] Once the polymer material constituting layer 14, 14' has been selected, it is necessary to adapt the temperature of the rolling plates so that it does not exceed the glass transition temperature of the chosen polymer material.

[0060] Thus, when the polymer material chosen is polycarbonate, the temperature of the laminating plates must not exceed 150° Celsius (°C).

[0061] When the polymer material chosen is polyamide, the temperature of the rolling plates must not exceed 145°C.

[0062] When the polymer material chosen is polyvinyl chloride, the temperature of the laminating plates must not exceed 80°C.

[0063] And finally, when the polymer material chosen is polyethylene terephthalate, the temperature of the laminating plates must not exceed 240°C.

[0064] In a particular embodiment, the manufacturing process includes, prior to the rolling step, a step of obtaining layer 14, 14' by The transparent polymer constituting it is rolled between two rolling plates whose surfaces in contact with the polymer material have an average surface roughness of less than 0.05 pm. This ensures that the resulting 14,14' layer meets the requirements of the second rule.

[0065] At the end of the lamination step of the manufacturing process which is the subject of the present invention, a secure document 10 is obtained which has a smooth mirror effect as shown in [Fig.4].

Claims

Demands

1. A method for manufacturing a secure document (10) having a mirror effect, said secure document (10) comprising at least: - a first layer (12) of which a first surface is disposed on a substrate (11) and a second surface (Fi2) is at least partially covered by a metallic layer (13); - a second layer (14) of transparent polymer covering, at least partially, the second surface (Fi2) of the first layer (12) and the metallic layer (13); said manufacturing method comprising at least one hot lamination step during which the substrate (11), the first layer (12) and the second layer (14) are assembled to form the secure document (10), the first layer (12) and the second layer (14) being bonded together by means of an adhesive material;and being characterized in that: - the rolling temperature is lower than the glass transition temperature of the transparent polymer constituting the second layer (14); - the average surface roughness of the adhesive material is less than 0.05 micrometers (pm); and - the average surface roughness of the surface of the second layer (14) in contact with the metal layer (13) is also less than 0.05 pm.

2. A method for manufacturing a secure document (10) having a mirror effect according to claim 1 in which the transparent polymer material constituting the second layer (14) belongs to the group comprising: - polycarbonate, - polyamide, - polyvinyl chloride, - polyethylene terephthalate.

3. A method for manufacturing a secure document (10) having a mirror effect according to claim 1 or 2, wherein the substrate (11) includes near-field communication means.

4. Method of manufacturing a secure document (10) having a mirror effect according to any one of claims 1 to 3 wherein the adhesive material is an ink.

5. Method of manufacturing a secure document (10) having a mirror effect according to claim 4 wherein the ink is a transparent ink.

6. Method of manufacturing a secure document (10) having a mirror effect according to any one of claims 1 to 3 wherein the adhesive material is a transparent resin.

7. A method for manufacturing a secure document (10) having a mirror effect according to any one of claims 1 to 6 comprising prior to the lamination step, a step of obtaining said second layer (14) by laminating the transparent polymer between two lamination plates whose surfaces in contact with the polymer material have an average surface roughness of less than 0.05 pm.

8. Secure document (10) exhibiting a mirror effect obtained by means of the manufacturing process according to any one of claims 1 to 7 comprising at least: - a first layer (12) of which a first surface is disposed on a substrate (11) and a second surface (F12) is at least partially covered by a metallic layer (13); - a second layer (14) of transparent polymer covering, at least partially, the second surface (F12) of the first layer (12) and the metallic layer (13); the first layer (12) and the second layer (14) being bonded together by means of an adhesive material.

Images