FR3013872A1 - METHOD FOR MANUFACTURING AN RELIEF RELATED CARD - Google Patents

Abstract

A method of manufacturing a card comprising a flat body which comprises a core layer 1 of which at least one face 1A is at least partly reflective and a transparent cover layer 3 adapted to cover the core layer, characterized in that an intermediate layer, in the thickness of which at least one cutout 2A has been formed, is interposed between the core layer and the cover layer and is applied to the stack of the core layer, the intermediate layer and the cover layer a lamination treatment capable of causing a deformation of the reflective surface portion in the cut of the intermediate layer.

Description

The invention relates to a method of manufacturing a card having an element having a visual effect in relief, in practice a data carrier card. It can be a microcircuit card. By microcircuit card means the set of a body having, between two parallel faces, a substantially constant thickness much lower than its other dimensions measured along directions measured in the plane of the parallel faces; it is in practice in the body that one can wish to realize a visual effect in relief. Such a microcircuit card can notably, but not necessarily, be in accordance with the formats known as the ID-1 abbreviated nomenclature according to IS07810 (corresponding to the format of credit cards), ID-000 (corresponding to the format of SIM cards), 3FF (also called micro-Sim format), even 4FF (nano-SIM format). Document US 2007/0272760 already discloses a method of manufacturing such a card having a three-dimensional relief appearance. It is proposed to deposit a metallic ink on an area of a face of a core layer of a future map, to cover only part of this area by means of a varnish and then to laminate on this face a layer cover ; a visual relief effect is obtained between the parts comprising only ink and the parts where varnish covers this ink. In practice, this impression of relief is obtained without inducing a significant variation in the thickness of the card. Such a technique involves the combination of two materials (metallic ink and varnish) which have different absorption capacities vis-à-vis the light and whose deposition methods (especially with regard to the varnish: viscosity, thickness, rate of deposition in particular) can be difficult to control. Also known from US-2011/0020606, a method of manufacturing a data carrier card having a three-dimensional image; this document teaches producing a relief image by pressing a first assembly formed of a deformable layer along a confomation layer, between a flat plate and a raised plate, and then pressing this first assembly and a second conformation layer between two plates so as to drown the layer in relief between the two conformable layers. However, it is understood that such a method involves two successive pressing steps, with different tools, which leads to a great complexity of implementation (especially in the case of reliefs of complex shapes), which may be incompatible with the presence of a microcircuit or antenna in the card body thus obtained. The principle of a metal layer embedded in a card body is also known from document US Pat. No. 7,503,503, but without the provision of relief since it is mainly a question of obtaining the combination of an impression and a metallic effect.

The object of the invention is to make it possible to obtain such a visual effect of apparent relief in a simpler way, with improved accuracy as regards the contours of the zones in apparent relief and a great freedom of choice of shape for the apparent relief to be achieved. The invention is of course generalized in the case of cards without microcircuit. The invention proposes for this purpose a method of manufacturing a card comprising a flat body which comprises a core layer of which at least one face is at least partially reflective and a transparent cover layer adapted to cover the core layer, characterized in that an intermediate layer, in the thickness of which at least one cutout has been formed, is interposed between the core layer and the cover layer and is applied to the stack of the core layer, the intermediate layer and the cover layer a lamination treatment capable of causing a deformation of the reflective surface portion in the cut of the intermediate layer. It may be noted that, compared with the technique described in the document US 2007/0272760, the invention allows a great precision in the definition of the contours of the apparent relief zones, combined with a great simplicity of implementation. Indeed, the definition of the contours is ensured by the precision of the cut (that we know how to make as precise as we wish) and the apparent relief effect is obtained by using such a cutting operation and at a simple lamination stage. It should be noted that it is an area of the reflective portion that deforms to fill the cutout of the intermediate layer at the same time as the underlying core layer. In fact, it could be assumed a priori that the presence of such a cutout would simply cause a local collapse of the cover layer in the cut without generating any visual effect; however, it has been found that, subject to applying sufficient pressure at a sufficient temperature, the lamination step can cause at least partial filling of the volume of the cut by the underlying material to the point of generating a relief effect. apparent, especially because of the warping of the reflective surface obtained locally along the contour of the cut. This deformation causes changes in the angle of incidence and reflection of the light on the edge delimiting the deformed area to obtain the final visual relief aspect, compared to the undeformed area located outside the contour. Moreover, the management of parameters such as the temperature, the pressure of the process and the type of material chosen as reflecting surface, can make it possible to accentuate or reduce the angle of inclination of the edge of the deformed zone and thus to increase or to reduce the visual relief effect. Indeed more the transition will be short between the deformed zone (the one that fills the volume of the cut) and the undistorted area (outside the contour), plus the visual relief effect will be strengthened. Advantageously, the intermediate layer is transparent. Also advantageously, the core layer comprises a support layer lined on at least a portion of its surface by a metal layer. In other words, the metal layer extends over at least a portion of the support layer.

According to another advantageous characteristic of the invention, the core layer comprises a support layer of which at least a part of the surface is covered by a metallic ink. According to yet another characteristic of the invention, the core layer comprises a support layer lined on at least a portion of its surface by a plurality of nanolayers consisting entirely of metal effect polymer. According to yet another advantageous characteristic of the invention, the stack to which the lamination treatment is applied has, unlike the intermediate layer with respect to the core layer, only one or more transparent layers and wherein the core layer is transparent under its reflective surface. According to another advantageous characteristic, the lamination step comprises a heating phase without application of pressure, a maintenance phase at a temperature at which at least the core layer is above its softening temperature (or its glass transition temperature) during which increasing pressure is applied, and a phase without heating during which the stack is allowed to cool while the pressure continues to increase. Also advantageously, the layers forming the stack are selected from thermoplastic materials. According to another aspect of the invention, it proposes a map of constant thickness with parallel faces, adapted to be produced by the method according to any one of the preceding definitions, comprising between its faces an intermediate layer and a reflecting surface which has, in at least one area, variations of level with respect to one of these parallel faces from which it is separated by transparent material, the reflecting surface passing through the intermediate layer facing at least one part of this area so as to make visible an apparent relief along an outline surrounding this area.

A card according to the invention differs in particular from a document such as the document US - 2011/0020606 in that it can distinguish a layer which is crossed at the location of cuts formed prior to assembly of all the layers, by the reflective layer. Advantageously, this card further comprises a microcircuit. According to another advantageous characteristic, the reflecting surface has, near this contour, an inclination of between 0.5 ° and 15 ° with respect to said face (or between 1 ° and 10 °, or even between 1 ° and 3 ° Objects, characteristics and advantages of the invention will become apparent from the description which follows, given by way of nonlimiting illustrative example with reference to the accompanying drawing, in which: FIG. 1 is a diagrammatic view in exploded section of a stack. of layers ready to be rolled to obtain an apparent relief effect, according to the invention, - Figure 2 is a sectional view of the map obtained by lamination of the stack of layers of Figure 1, according to the line AA FIG. 3 is a perspective view of the map of FIG. 2. As shown diagrammatically in FIG. 1, the method of the invention comprises the preparation of at least three layers 1, 2 and 3. 3.

The layer 1 is a core layer (which may be called inlay) of which one face (here the upper face) is at least partially reflective. In the present invention, the term "reflective" is understood to mean the property possessed by a surface of a material having a significant reflection index and a very low absorption and transmission index where at least 70% of the incident light ray is Reflected, only 30% or less of the light beam is transmitted and absorbed. These optical properties are particularly observed for metallic or metallic effect materials. For reasons of readability, this reflecting face is shown in Figure 1 by a surface layer designated by the reference 1A; this surface layer is reflective here on all the part shown in this figure. The layer 2 is an intermediate layer in which at least one cutout 2A has been formed by any appropriate known means, the contour of which corresponds to the relief that is to be made apparent.

Layer 3 is a transparent cover layer that is inherently conventional; it may be a single layer or a stack of transparent layers. The transparent character can be obtained with a material that is hardly translucent, but used with a sufficiently small thickness so that the layer is transparent at least in the range of wavelengths in which it is desired to reveal the apparent relief effect. Advantageously, there is at least one cover layer on the opposite side of the core layer (here denoted 4), for example of the same dimensions and in the same material as the layer 3. Other layers may be interposed between the layer 1 and the layer 4. When at least these three layers 1, 2 and 3 have been prepared, they are assembled by lamination, that is to say that these layers are superposed in a stack that the it is subjected to a suitable pressure for a suitable time at a suitable temperature so that the core layer, at least as regards its reflecting face, deforms to occupy the volume of the cut. The choice of these operating conditions is within the abilities of those skilled in the art, given their experience in view of the materials chosen (a limited number of tests may be useful to finalize the choice of these operating conditions). In practice, the lamination step comprises at least one high temperature phase, that is to say a phase involving a heating of the layers, typically above 100 ° C, to promote the filling of the volume of the blank by softening adjacent materials; there may be a high temperature phase followed by a phase at room temperature (that is to say without voluntary heat supply, which is to say that there is a cooling, whose speed can be chosen depending on the needs). These two phases can be followed by maintaining the application of a pressure, which one can choose to increase the level with the time. Preferably, the lamination step comprises a temperature rise phase without applying pressure, until reaching (or exceeding) the softening temperature of at least the core layer and its reflective effect face; preferably, a good bond by lamination is obtained when each of the layers has reached or exceeded its softening temperature, without deformation of the contour of the cut (even if it is admitted that, during the subsequent application of pressure, the wafer of the intermediate layer can taper bevel to locally follow the reflecting surface which has been deformed upwards to occupy the volume of the cut). When the temperature has reached a predetermined set temperature, the pressure is first applied and gradually increased so as to flow the material constituting the reflective face of the core layer into the volume of the cut of the intermediate layer. ; it is then possible to cease any heat input (and thus to allow the stack of layers to cool) while continuing to increase the applied pressure (this has the particular effect of preventing the trapping of air bubbles from the initial volume The pressure and temperature parameters are advantageously chosen to obtain the shortest transition between the deformed core layer and the undistorted core layer, that is to say at an angle of inclination to the as much as possible compared to the initial plane of the core layer In practice it is not necessary to aim at an inclination angle greater than about 15 °, while a substantial relief effect can be detected at a slope of a fraction of a degree, for example 0.5 ° A range of 1 ° to 10 °, or even between 1 ° and 3 °, seems to be a good compromise between the visible character of the relief effect and simplicity of implementation of the treatment of In order to remain within industrially acceptable ranges, the duration of the lamination step during which pressure is applied is advantageously less than 1 hour (a minimum duration seems to be 10 minutes). By way of example, the lamination step comprises a high temperature phase, during which it is possible not to apply pressure, and a descending temperature phase (possibly up to the ambient temperature corresponding to an equilibrium with outside without voluntary heat supply), whose durations are 40% to 60% of the total duration. The maximum temperature is in principle between 100% and 250% of the softening temperature in ° C (depending on the case, it may be the glass transition temperature), and the maximum pressure applied during the cooling step. cooling is preferably between 100 and 300 N / cm 2.

Advantageously, the lamination operation is applied to large layers and is followed by a card format cutting operation within the laminated stack obtained from these large layers. The cards thus cut are advantageously in one of the formats defined by the ISO 7816 and / or ISO 7810 standard. To do this, the core layer preferably has a thickness of between half (or even two thirds) and 90% of the desired final thickness, and the cumulative thicknesses of the other layers are between 10% and half (or even between 10% and one third) of the desired final thickness.

The preparation of the core layer, or even that of the other layers may be modified, in a manner known per se, to form a cavity in which a microcircuit is then embedded (in practice after the lamination step but before the cutting step when the lamination step is applied to large dimensions) or to allow the implantation of electronic circuits, such as an antenna on one side of the core layer, for example. It can be noted that the visual effect of relief can be obtained with a metal layer whose thickness is sufficiently small not to change the performance of such an antenna. FIG. 2 represents in section a map obtained by lamination of the layers of FIG. 1, with a transition of angle α between the deformed zone (inside the volume of the blank 2A initially formed in the layer 2 and the non-zone the deformed zone has a transition zone following the contour of the initial cut (the edge of the cutout having inclined at the angle of inclination) surrounding a planar deformed zone, skirting here the cover layer, the layer 1 may be formed of one or more layers assembled by any appropriate known means, it may be a stack of layers previously laminated, it may also be a stack of layers assembled at the time of assembly of the layers 2 and 3 (and the layer 4 when it exists) with the layer 1. In the example shown, the layer 1 is formed of a support material plastic 1 B pa a thin metallized layer forming the reflecting surface 1A; this thin metallized layer may consist of a metallic ink deposited by any appropriate known means. As a variant, the layer 1 may consist of a support consisting of the superposition of a layer of thermoplastic material (for example of PVC) and of a smooth thermoplastic layer (for example made of PET), and of a metal layer thin reported on this support; an advantage of implementing a metallized sheet attached to a support is that this sheet is likely to deform more easily than the support itself (this will be discussed later); furthermore, in practice, a metal foil does not exhibit significant defects (at least in its initial state), which makes it possible to obtain a reflective appearance of better quality than a layer of metallic ink which may exhibit variations thick, even some coarse defects formed during the deposition of the ink.

According to yet another variant, the layer 1 may be formed of a support, for example PVC, along a surface layer of plastic (for example thermoplastic) loaded with metal particles, or a surface layer consisting of nano Polymer (without metal particles) metal effect coatings. It may in particular be a material diffused by Toray Industries Inc. under the designation "Picasus®". The layer providing the reflective effect may cover the entire face of the support, or cover only a part; it can be provided by screen printing, or can be made in the form of a pre-cut thin layer which is then laminated to the support. The invention takes advantage of the fact that the surface of the core layer, in at least the examples mentioned above, makes it possible, after deformation in the direction of the thickness of the future map, to have an apparent visible visual effect that is easily perceptible. by a user with the naked eye.

It should be noted that, apart from the layer having the reflective appearance, the core layer may be, at the choice of the designer of the card, opaque, translucent or transparent. An advantage of choosing for the layer 1 a transparent material, in combination with a cover layer 4 directly related to this layer 1, is that the relief from the deformation of the at least partly reflective face 1A is visible on both sides of the future map (the apparent relief visible on one face being the negative of the visible relief on the other side). This is another advantage over the known technique using a varnish on a portion of a metallized ink-coated area, since it is necessary to deposit varnish under each of the faces through which it is desired to observe an apparent relief The layer intermediate 2 is in practice plastic, preferably thermoplastic; it may be noted in this respect that it is within the abilities of the person skilled in the art to choose operating conditions for rolling so that there is no change in the geometry (apart from a possible inclination of the edge) of the contour of the blank (or blanks) during rolling operations despite the associated heating. The intermediate layer may be opaque, but the apparent relief effect is mainly obtained if this layer is transparent (possibly less transparent than the layer 3), because the tilting effect of the edge delimiting the deformed zone with respect to the zone undistorted is then more visible; the choice of an opaque layer has the effect that the reflective zone is visible only through the cut, but there may be cases where a simple relief effect inside the cut, along its outline, may be sufficient for the needs of the designer of the card. This layer 2 may in particular be PVC, PC. This intermediate layer may itself be formed of several layers having different cuts for example nested, which is to say that there is an intermediate layer having an opening whose slices have steps (in the direction of the thickness of the future map); it is understood that by choosing the cutouts and the materials (opaque or transparent) of these intermediate layers, one can obtain relief effects that can be complex with different levels of apparent relief. The cut (or blanks) 2A can be obtained by the use of machines manufactured by companies such as ESKO or ZÜND For example, the layers have thicknesses such that, after lamination , their cumulative thickness is in accordance with the ISO 7816 standard, that is to say of the order of 760 micrometers, such a thickness can thus be obtained by lamination of a layer 1 of 600 micrometers, a layer intermediate 2 of 50 micrometers and a cover layer 3 of 60 micrometers, it may also be a stack of a core layer of 650 microns, a middle layer of 60 microns and two layers of cover 3 30 and 4 of 50 micrometers The thickness of material providing the reflective appearance (ink or added layer) may be of the order of 0.1 to 10 micrometers.

The various layers are for example PVC. The lamination is for example carried out by carrying out a stack of layers and heating this stack up to 160 ° C, maintaining the stack at this temperature for 20 minutes by applying a pressure increasing to 150N / cm2 (or 15 bar) then stop heating while increasing the pressure up to 250N / cm2 (25 bars) after 20 minutes. Angle angles of the order of 1 ° to 3 ° were obtained for these conditions, leading to quite satisfactory visual relief effects.

FIG. 3 represents, by way of example, a map in plan view comprising a module 10 comprising a microcircuit and contact zones intended for communication by contact with an external reader of appropriate format; it can be a credit card. There is a relief of freely chosen shape, designated by the reference 20, determined by the contour of the cut 2A. If the core layer has been chosen in a transparent material and if there is no other layer or layers all transparent on the hidden side of the map, an apparent relief would be visible in negative by observing the map by its other face. A card formed by the method described above is recognized by the fact that it comprises, between its parallel faces, a reflective surface having variations of level with respect to one of these faces, crossing from place to place a intermediate layer (layer 2); the transition between the areas where the intermediate layer is present and those where the intermediate layer is not present at an inclination angle advantageously between 0.5 ° and 15 °, preferably between 1 ° and 10 °, or between 1 ° and 3 °. This emerges from FIG. 2, in which the layer constituting the reflecting face has bulged during lamination until it occupies the volume of the opening formed by the cut 2A, the heating during lamination having caused a filling of the volume. internal of the cut and a local deformation of the edge of the intermediate layer along the initial cut.

Claims (11)

REVENDICATIONS1. Method for producing a card comprising a flat body which comprises a core layer (1) at least one of which is at least partially reflective (1A) and a transparent cover layer (3) adapted to cover the core layer , characterized in that an intermediate layer, in the thickness of which at least one cutout (2A) has been formed, is interposed between the core layer and the cover layer and is applied to the stack of the layer of core, the intermediate layer and the cover layer a lamination treatment capable of causing a deformation of the reflective surface portion in the cut of the intermediate layer. 2. Method according to claim 1, wherein the intermediate layer is transparent. 3. A method according to claim 1 or claim 2, wherein the core layer comprises a support layer 1B along at least a portion of its surface by a metal layer (1A). The method of claim 1 or claim 2, wherein the core layer comprises a backing layer at least a portion of the surface of which is covered by a metallic ink. 20 The method of claim 1 or claim 2, wherein the core layer has a support layer lined on at least a portion of its surface by a plurality of nanolayers consisting entirely of metal effect polymer. 6. A method according to any one of claims 1 to 5, wherein the stack to which the lamination treatment is applied has, opposite to the intermediate layer with respect to the core layer, only one or several possible transparent layers and in which the core layer is transparent under its reflecting surface. 7. Method according to any one of claims 1 to 6, wherein the lamination step comprises a heating phase without applying pressure, a holding phase at a temperature at which at least the core layer is above its softening temperature during which increasing pressure is applied, and a phase without heating during which the stack is allowed to cool while the pressure continues to increase. 8. Method according to any one of claims 1 to 7, characterized in that the layers forming the stack are chosen from thermoplastic materials. 9. Card of constant thickness with parallel faces, adapted to be produced by the method according to any one of claims 1 to 8, comprising between its faces an intermediate layer and a reflecting surface which has, in at least one zone, level variations with respect to one of these parallel faces from which it is separated by transparent material, the reflecting surface passing through the intermediate layer facing at least a portion of this zone so as to make visible an apparent relief according to an outline surrounding this area. 10. The card of claim 9 further comprising a microcircuit. 11. The card of claim 9 or claim 10, wherein the reflecting surface has, near this contour, an inclination of between 0.5 ° and 15 ° relative to said face.