ES2702817T3 - Print layer with main pixels and satellites on a stratified polymeric composite for a security and / or value document - Google Patents

Abstract

Layered polymeric composite for a security and / or value document comprising at least two layers of polymer bonded cohesively to each other, where at least on one surface of at least one of the polymeric layers there are applied printed layers respectively formed by pixels a printing area, wherein the printed layer is generated by an ink jet recording, characterized in that each printing pixel consists of a main pixel and at least one satellite pixel associated with the main pixel, and because the presence of satellite pixels in addition of the main pixels to which they are associated represents a security feature of the security and / or value document.

Description

DESCRIPTION

Print layer with main pixels and satellites on a stratified polymeric composite for a security and / or value document

Scope of the present invention

The present invention relates to a stratified polymeric compound for a security and / or value document and to a method for its production. In addition, the present invention relates to a security and / or value document that can be obtained from the layered polymeric compound of the present invention, for example, by plasticizing the compound in transparent protective films. Furthermore, the present invention relates to the use of the security and / or value document as an identity document, passport, credit card, bank card, cash payment card, customer card, Visa card, identification card or license. of driving.

Technical state and background of the present invention

The data carriers in the form of a card serve, for example, to identify persons and / or objects and / or for cashless payment services. Among other things they have visually recognizable characteristics, clearly related to a person and / or an object and / or a bank or securities account, and only allow the owner to identify himself or dispose of the object or account and order money transfers. For this reason, these data carriers must have security features that practically do not allow unauthorized people to trick or falsify the cards, avoiding misuse as much as possible. In addition, therefore, a counterfeit must be easily recognizable.

To protect against counterfeiting or adulteration it has been proposed to date that known data carriers in the form of a card carry a number of different security features and have also been implemented, such as guilloches, watermarks, stamping marks, candling records, photos of passports produced by laser engraving, holograms, ambiguous images, fluorescent marks and other diverse characteristics. These characteristics serve to make counterfeiting difficult or almost impossible. For this purpose, the reproduction of these characteristics must be extremely difficult.

The essential security features in data carriers in the form of a card are of a personalized and / or individualized type and are stored in the data carrier. The personalized features are, for example, passport photos and data of the person to whom the card is assigned, such as the date of birth, the address or the identification number of a company, and also biometric data, such as a digitized record of the fingerprints or the size and color of the person's eyes or their affiliation to a medical insurance. Individualized characteristics are data related to a specific medium, such as a vehicle, a bank account or an action.

These personalized and / or individualized characteristics are introduced specifically in the data carriers in the form of a card for the person who uses them. Therefore, your production process must be flexible. For example, the methods and apparatuses for entering such data into the card-shaped supports are described in patents US 6,022,429 B1, US 6,685,312 B2, US 6,932,527 B2, US 6,979,141 B1 and US 7,037,013 B2, where the personalized characteristics and / or individualized can be applied to the cards, using among other techniques inkjet printing. Some of the patents cited above also indicate that these data are coated after application with a protective sheet.

EP 0384274 A2 describes a process for creating a multilayer identification card in which specific safety data are introduced by an inkjet printing method. The error diffusion method compensated by superposition of points is used. As an additional security effect it turns out that the compensation of the superposition of points depends on the size and shape of the point.

In the case of ink jet printing or another method of applying ink drops on a printing medium ("drop-on-demand" method ), it has also been reported that, if necessary, They can create satellite pixels in addition to the main pixels produced during printing. In an impression these satellite pixels are avoided to produce a perfect image. Therefore not only a uniform drop is formed, but, depending on the properties of the ink and the conditions in which the drops are formed (for example, the shape of the flank of the electrical signal that determines the ejection of drops of the injector to operate the nozzle, piezoelectric actuator or jet of bubbles), more or less long "tails de gota" appear, whose speed is lower than that of the initial drops and from which other satellite drops can be formed subsequently (H .Wijshoff in: "Drop formation mechanisms in piezo-acoustic inkjet [Mechanisms of formation of drop with piezoacoustic inkjet]", consulted in http://www.flow3d.com/pdfs/tp/micro_tp/FloSci-Bib01-07 .pdf on 8.2.2008). These satellite drops fall with delay and, if no optimizing measure is taken, with a displacement with respect to the center of the main drop in the printing medium, due to the relative movement of the print head on said medium. When the displacement between both drops is sufficient, a main pixel and a satellite pixel (generally smaller) are formed on the printing medium.

It is known from US 2003/0179258 A1 that the formation of satellite drops can be reduced or minimized by using a plate with channels before the device next to the recording head, from which the ink drops emerge. This plate is formed and arranged to vary the trajectories of the satellite drops coming out of the print head, while the main drops are ejected in the main direction practically unaltered. This allows to selectively influence the trajectories of the satellite drops with respect to those of the main drops, which makes it possible to reduce or avoid the appearance of satellite pixels.

Furthermore, the patent US 7,093,915 B2 indicates how the direction of a subsequent satellite drop can be changed to a main drop with respect to the direction following the main drop at the exit of the print head, so that the satellite drop falls into the main pixel on the printing medium for a certain relative speed of the recording head relative to the printing medium, a defined distance of the recording head to said medium and the flight speeds.

Likewise, from DE 19900856 A1 a method for coding a primary image with a secondary image is known, which consists of crosslinking the primary image and the secondary image. The secondary image is hidden in the primary image, compensating it or equaling it with its own inverse reproduction. To unify both images (the primary image and the secondary image matched by compensation with its own reverse reproduction) a coding method is used in which the points of the reticulated primary image are modified or altered so that the compensated secondary image is invisible in the primary image. To do this, the points are grouped in the primary image and the information of the secondary image is introduced in these groups of points. The variations can be density, shape and appearance, angle, position, size or frequency of each point in the groupings of points.

Likewise, patent DE 19706008 C2 indicates a method for increasing the security against forgery of variable graphic elements, in particular of alphanumeric characters, images, bar codes, specified in security and securities documents, by which at least the surfaces of the variable graphic elements are endowed with fine microscopic structures and a defined relationship is established in code form between the spectral and / or geometric properties of the structures in terms of colors and patterns, and the variable graphic elements that must be protected. Thus, for example, as a safety feature, chromatic information is proposed for the graphic structure. Specifically, for the alphanumeric characters you can define color codes, which are repeated in the structures of the individual elements. In the example shown there the letter "c" is modified by engraving on its surface a strip in the form of a c that constitutes a protective structure, the letter is assigned an identical color to the color of the protective structure of the "c".

Nowadays, high-quality data carriers in the form of a card are specifically made of polycarbonate. Polycarbonate-based cards are customized and / or individualized by laser engraving. The laser beam focuses on the material and is guided over it. During the process the laser beam produces blackening by pyrolysis inside the material, whose intensity varies according to the power and duration of the laser at the respective points. In this way you can generate an image or any other graphic, or even a logo or a combination of numbers and / or letters.

However, this method does not allow producing images or color graphics or written or numerical sequences, but only black and white representations. At most, gray tones / gradations can also be generated to a certain extent. Therefore, there have been attempts to produce colored representations on the cards by printing techniques. However, this has been problematic because the usable printing inks are not adequate for making the cards. Sometimes, when a printed polymeric sheet has been joined with other sheets, for example, by lamination, the internal pressure may cause the delamination of this laminated laminate or other method due to manipulations in the printed layer. According to the chemical nature of the ink, incompatibilities arise that manifest as lack of adhesion. In particular, water-based inks can be easily eroded by rubbing on a series of polymers (eg polyolefins, polyesters, polycarbonates), which causes problems even before bonding. This vulnerability of the security and / or value document is not acceptable because it facilitates falsification or adulteration of the document.

Technical problem of the present invention

Starting from this basis, the present invention initially faces the problem that a laminate elaborated by printing techniques with personalized and / or individualized characteristics can be delaminated or divided by unauthorized manipulation, and therefore it is desirable to find a method that allows it to be avoided. safe way.

In addition, attempts have been made in the past to find suitable methods for providing new safety features contained in a polymeric laminate, based especially on polycarbonate. Therefore, the present invention has the additional objective of finding new guarantee characteristics for security and / or value documents, whose possibility of falsification or adulteration is practically excluded.

Brief description of the present invention

Whenever used in the description and in the claims, the term "representation" refers to both a printed reproduction structured in any way, as well as a reproduction printed on its entire surface. The structured printed reproduction can be, for example, an image such as a passport photograph, or a graphic reproduction, for example, guilloches or a cross-linked background, or alphanumeric characters or a one-dimensional or two-dimensional bar code or an emblem, shields of weapons, national badges or any other printed reproduction.

Whenever used in the description and in the claims, the term "pixel" refers to the smallest possible element during the printing of a reticulated image. Pixels usually have simple geometric shapes, such as circles or squares. Ink jet printing generally creates circular or quasi-circular shapes defined by the diffusion of the ink spot in the printing medium. The totality of the pixels of an image forms a reproduction thanks to the relative arrangement between them.

As used in the description and in the claims, the term "satellite pixel" refers to an ink spot on the printing medium which in certain conditions appears in addition to the main ink spot, ie the main pixel, in a printing process based on the application of drops. A satellite pixel accompanies a main pixel and therefore is in close spatial relationship with it. The satellite pixel is usually very close to the main pixel and can ideally merge with it or, if necessary, separate from it, if more satellite pixels formed at a greater distance from the main pixel should be generated. Then a bimodal pixel appears formed by the main pixel and the satellite pixel when the distance between them is not very small, but, on the other hand, not so big for both pixels to be separated. Satellite pixels are characterized, among other things, by being in a fixed geometric relationship with respect to the main pixels they accompany, for example, being always on the line of connection between adjacent main pixels or forming a certain angle with respect to this connection line. , unless there are splashes of printing ink produced statistically by ink stains. If the printing direction is reversed (the direction of relative movement between the recording head and the printing medium), this angle is also reflected in a line perpendicular to the direction of printing. However, it can also be envisaged that certain printing pixels composed of main pixels and satellite pixels, for example pixels of a certain color and / or size, have a first spatial orientation with each other and other pixels, for example of a color and / or different size, a varied geometric relation with respect to the first one. Therefore, the main and satellite pixels of the adjacent main pixel-satellite pixel sets can also be arranged geometrically different from each other, although within a group only sets with the same geometric orientation are respectively found. Therefore, there can also be adjacent sets with different geometric orientations, as long as they belong to different groups. A fundamental characteristic of satellite pixels is that they are usually smaller than the main pixels they accompany.

As used in the description and in the claims, the term "digital printing method" refers to a printing process in which the data required for the generation of images are digitally processed and used to print directly, as in the inkjet injection printing method, or indirect, as in a xerographic printing method, and obtain the printed image, without the need for an explicit typographic form. It is a non-impact printing process, that is, a method in which no solid typeface (a printing cylinder or a piston) is used.

In order to produce new security features against counterfeiting and adulteration, the present invention proposes a stratified polymeric compound for a security and / or value document, for example, for a credit card, bank card, cash payment card , customer card, visa card, identification card or for a driving license, passport, identity document, which has at least two layers of polymer bonded together by adhesion, so that on at least one surface of the less one of the polymer layers are formed printed layers formed respectively by pixels printed in a printing area. According to the present invention, the printed pixels consist respectively of a main pixel and of at least one satellite pixel that accompanies the main pixel.

Said stratified polymeric compound is prepared, according to the present invention, by the following process steps: (a) preparation of the polymer layers for the stratified polymeric compound; (b) forming the respective printing layers consisting of pixels printed on at least one surface of at least one of the polymer layers in a printing zone, so that the printed pixels consist respectively of a main pixel and at least one a satellite pixel that accompanies the main pixel; and (c) bonding the polymer layers together.

The starting point of the present invention is the recognition that it is possible to generate new security features in security and / or value documents using pixel printing methods and by varying the individual points of a reticulated reproduction, in particular of personalized characteristics and / or individualized, so that a main pixel and a satellite pixel associated with it are respectively generated. The complete reproduction is then composed of main pixels and satellite pixels associated with them.

As a general rule, the methods of printing by pixels and in particular the method of inkjet printing are configured in such a way that the respective printed pixels have the most reproducible shapes, surfaces and color densities. For this purpose, printing is optimized so that satellite pixels do not form. Each printed pixel is then ideally formed by a circular area. Therefore, the presence of satellite pixels in addition to the main pixels, to which they are associated, is a security feature in the security and / or value document. Accordingly, if such a satellite pixel is not detected in a security and / or value document, although the standard document should be printed with these pixelated forms, falsification or adulteration can be easily identified.

It has been said previously that satellite pixels are smaller than the main pixels to which they are associated. Regarding the relative diameter of both types of pixels, it refers to the previous definition.

Normally a single satellite pixel can be associated to each main pixel generated in the reproduction. This is achieved by an adequate electronic control of the print head. In particular, the rising edge of the actuator is optimized (piezoelectric crystal, heating by electrical resistance of the printer by ink jet-injection of bubbles), with which individual drops of ink are ejected from the print head. This is because the main part of a drop is driven at high speed by an exit hole of the printhead, but a smaller part still comes out when the drive process is completed and the meniscus of the liquid ink begins to back out of the exit hole ("fill-before-fire-action [load before firing] 1). In this phase the outgoing liquid ink is delayed with respect to the initial liquid parts, forming a liquid path that in case of sufficient delay extends and then under certain conditions can also form individual drops (satellite drops) in the back (tail) . These other parameters for the generation of satellite drops are attributable, among others, to the composition of the ink, in particular with respect to its viscosity and surface tension, which have a significant influence on the formation of satellite drops producing satellite pixels. For example, a high surface tension of the liquid ink relative to air is advantageous for the formation of individual ink droplets. The inertia of the liquid ink also has a significant influence. This is shown in more detail in H. Wijshoff, ibid.

The security feature according to the present invention can be realized as a structured reproduction of any form, for example an image such as a passport photo, or as a graphic, as guilloches, or as a grid, in particular a background grid (for example example in the form of rhombuses, crow's feet, pips, fishbone, chessboard), or as alphanumeric characters, for example to represent personalized data of the owner or the identified item (for example a motor vehicle), or as a bar code or an emblem, a coat of arms, a national flag, a flag, a guarantee mark, a seal. Basically there are also other possible structured reproductions. Furthermore, the reproduction can also simply be a uniformly colored surface without structure, such as a white, black, gray or any other surface.

In reproduction, all or only certain groups of printed pixels clearly identifiable as sets of principal pixels-satellite pixels can be structured. For example, all non-black printed pixels can be provided with satellite pixels.

Detailed description of the present invention

The present invention relates to a composite of polymer layers, which optionally may also contain layers of other materials, for example, cardboard, paper, fabrics, fabrics, meshes, or those known as prepregs, for the production of security documents and / or of value.

In principle all the usual materials in the field of security and / or value documents can be used as materials for the polymeric layers. The polymer layers can be based in the same or different way on a polymeric material from the group consisting of PC (polycarbonate, especially bisphenol A polycarbonate), PET (polyethylene glycol terephthalate), PMMA (poly (methyl methacrylate)), TPU (thermoplastic polyurethane elastomers), PE (polyethylene), PP (polypropylene), PI (polyimide or poly-trans-isoprene), PVC (poly (vinyl chloride)) and copolymers of said polymers. Co-extruded sheets of these materials can also be used. The use of PC materials is preferred, for example, but in no way necessarily, so-called low Tg materials based on polycarbonate can be used, in particular for a polymeric layer on which a printing layer is applied, and / or for a polymeric layer bonded onto the printed side of another polymer layer bearing the imprint. The materials of low Tg are polymers whose glass transition temperature is lower than 140 ° C.

The polymer layers can be used with or without fillers. The charged polymer layers contain in particular colored pigments or other fillers. The polymer layers can also be stained with dyes or leave colorless, and in the latter case they can be transparent, translucent or opaque.

It is preferable that the base polymer of at least one of the polymer layers to be bonded contain reactive groups equal to each other or different, so that, at a lamination temperature lower than 200 ° C, the reactive groups of a first polymer layer react with each other and / or with reactive groups of a second polymer layer, which allows to lower the rolling temperature without endangering the intimate union of the laminated layers. In the case of several polymeric layers equipped with reactive groups, this is due to the fact that such layers can no longer be it can be easily separated by reacting the respective reactive groups, since a reactive coupling, that is to say a reactive lamination, takes place between the polymeric layers. In addition, thanks to the lower lamination temperature, the alteration of a printed layer in color, especially a chromatic change, can be avoided. It is desirable that the glass transition temperature Tg of at least one polymer layer, before thermal lamination, be less than 120 ° C (or less than 110 ° C or less than 100 ° C), so that the transition temperature This polymeric layer after the thermal lamination by reacting the reactive groups of the base polymer of the polymeric layer with each other is at least 5 ° C, preferably at least 20 ° C, higher than the glass transition temperature before lamination Thermal In this case, not only reactive coupling of the laminated layers occurs between them. In fact, it increases the molecular weight and, therefore, the glass transition temperature, by cross-linking the polymer within the layer and between the layers. This further complicates the delamination, since, for example, the printing inks are irreversibly damaged, especially in the case of an attempted manipulation, by the high temperatures necessary for the delamination and as a result the document is destroyed. The rolling temperature when such polymeric materials are used is preferably less than 180 ° C, more preferably less than 150 ° C. The choice of suitable reactive groups is not problematic for a specialist in the field of polymer chemistry. The reactive groups are chosen, for example, from the group consisting of -CN, -OCN, -NCO, -NC, -SH, -Sx, -Tos, -SCN, -NCS, -H, -epoxy (-CHOCH2), -NH2 , -NN +, -NN-R, -OH, -COOH, -CHO, -COOR, -Hal (-F, -Cl, -Br, -I), -Me-Hal (Me = at least divalent metal, example Mg), -Si (OR) ³ , -SiHab, -CH = CH 2 and -CO R ", where R" can be any reactive or non-reactive group, for example H, Hal, C 1 -C 20 alkyl, C 3 aryl C20, C4-C20 aralkyl, respectively branched or linear, saturated or unsaturated, optionally substituted, or corresponding heterocycles with one or more identical or different N, O or S heteroatoms. Naturally, other reactive groups are also possible, including the reactants of the Diels-Alder reaction or a metathesis.

The reactive groups can be attached to the base polymer directly or through a spacer group. As spacer groups are suitable all those known to the specialist for polymer chemistry. The spacer groups can also be oligomers or polymers that impart elasticity, which reduces the risk of breakage of the security and / or value document. These elasticizing spacer groups are known to specialists and therefore need not be described here. Just as an example may be mentioned spacer groups selected from the group consisting of - (CH2) n-, - (CH2-CH2-O) n-, - (SiR2-O) n-, - (C ⁶ H ⁴⁾ n- , - (C ⁶ Hio) n, -alkylene Ci-Cn, -C ³ -C arylene (n + ³ ), -C ⁴ -C-alkylene (n + ⁴ ), respectively branched or linear, saturated or unsaturated, optionally substituted , or the corresponding heterocycles with one or more heteroatoms O, N or S the same or different, where n = 1 to 20, preferably 1 to 10. For other reactive groups or modification possibilities refer to the "Ullmann Encyclopedia of industrial chemistry" , Wiley Publishing, 2006 electronic edition. In the context of the preceding embodiments, the term "base polymer" designates a polymer structure that does not carry any group that is reactive under the lamination conditions employed. It can be homopolymers or copolymers. In addition to said polymers, modified polymers are also included.

The present invention serves to produce security features in security and / or value documents. The security features can be, in particular, personalized and / or individualized, which means that the printed reproduction represents a personalized and / or individualized characteristic. The personalized feature can be specifically a passport photo. In principle, a personalized feature can also include data of the person to whom the security and / or value document is assigned, for example, the date of birth, the address or the identification number of a company, as well as biometric data , such as a digitized fingerprint record, or the height and color of the person's eyes or their affiliation to health insurance. Basically an individualized characteristic can represent data belonging to a particular item, such as a motorized vehicle, or to a specific title, for example, a bank account or a security.

In turn, the personalized and / or individualized feature is modified by the representation of each printed pixel in a main pixel and a satellite pixel as an additional security feature, that is, despite this variation the printed image is distinguishable to the naked eye , while with a suitable optical magnification it can be recognized that the individual printed pixels are formed as sets of main pixels and satellite pixels.

The special crosslinked structure according to the present invention, with main pixels and satellite pixels, is preferably made by a digital printing method (non-impact printing), more preferably by a controlled drip method, and especially by a printing method by ink jet. If an inkjet printing method is used, the main and satellite pixel sets can be created by simply adjusting the printing process. In other cases these sets are simply simulated. Therefore, in principle all the printing methods that allow simulation of said sets in a reticulated reproduction of the individual elements of the image (pixels) can be used. This presupposes, of course, that the printing method used achieves a sufficient resolution to be able to produce the image elements composed of main pixels and satellite, as well as a conventional reproduction composed of points whose image quality is sufficient for the naked eye. For this purpose, the following printing methods can also be applied in principle: conventional printing methods, such as wet and dry offset, and other methods of planographic printing, gravure printing, relief printing, but also electrophotographic or thermographic methods. Printing methods are preferred digital and, in addition to the ink jet printing system, also, for example, xerographic methods, because they are very flexible, especially to produce personalized and / or individualized patterns.

In a preferred embodiment of the present invention, the pattern is produced with an ink jet recording head on one of the surfaces, so that the pattern is subdivided into pixels and at least a part of these pixels is composed of principal pixels and satellite in the sense of the present invention. According to a very preferred embodiment of the present invention, each satellite pixel is generated on the surface with respect to a main pixel which it accompanies, forming a predetermined angle with respect to the direction with which the ink jet printhead and the surface move relative to each other (printing direction). This means that the satellite pixels, looking at the surface after printing, are oriented very specifically with respect to the associated main pixels, for example in the "5 o'clock position" or the "nine o'clock position". "

Furthermore, it is especially preferred that said angle a is not 0 ° or 180 ° with respect to the printing direction. By maintaining these angles, the satellite pixels are located on the joining lines of the main pixels, which are printed one after the other in the process (scanning) of the print head and the printing medium relatively to each other. Such orientation would also normally be obtained with conventional ink jet printing, even if there were no special devices to suppress the satellite pixels, since the satellite drops impact later than the main drops in the printing medium, due to their lower speed. exit of the holes of the print head, and due to the displacement occurred while moving the print head next to the main pixel, above the line joining the main pixels printed successively. Depending on the direction of printing, a satellite drop may appear to the right or left of the main pixel. In any case, taking into account the direction of movement of the printhead, the satellite pixel will always appear behind the main pixel. On the other hand, when fulfilling the condition of a t 0 ° and a t 180 °, the satellite pixels are not printed on the lines of union, but above or below them. This orientation can only be adjusted if concrete measures have been taken to selectively divert the satellite drops at an angle p relative to a plane defined by the respective main pixel and the printing direction. Thus, it is precisely this condition of production of the satellite drops that allows recognizing that the satellite pixels have been selectively generated. In particular, each satellite pixel can be formed on the surface independently of the printing direction with respect to the corresponding main pixel to which it is associated, at an angle predetermined with respect to a joining line of adjacent printed main pixels.

This is achieved by properly adjusting the print head and / or its adjustment. For this purpose there is a device in the printhead to divert the satellite drops to the output thereof. By adjusting it and / or configuring it in an appropriate way this deviation can be achieved. In particular, this device can have a device with through holes that is directly adjacent to the output holes of the print head. By properly adjusting and / or configuring the device to divert the drops of satellite ink, the portion of liquid ink that ultimately forms the satellite pixels comes out at an angle p relative to a plane defined by the corresponding principal pixel and the printing direction . This portion of liquid ink is formed with the tail of liquid ink ejected, whose flight speed is lower than the speed of the liquid ink portion that lies at the head of the ejected liquid path and forms the main drop during flight.

The device for diverting the satellite drops can be constituted, as in the patents US 7,093,915 B2 or US 2003/0179258 A1, by a plate of through holes that is put in direct contact with the part of the printhead in which it is placed. find the outlets of the liquid ink. The through holes of this plate are communicated precisely with the exit holes of the print head. However, the plate is not mounted on the print head so that the exit holes are aligned with the through holes, but with a small displacement, so that although there is a free cross section for the passage of the ink liquid, this section is narrowed. By means of a lateral movement of the plate with respect to the recording head, the tail of the liquid path receives a pulse parallel to the plane of the plate, so that the satellite drop (s) formed in the tail deviates (n) of the original direction of ejection of the main portion of the liquid ink. The main drop maintains the exit direction defined by the perpendicular to the plane defined by the output holes of the printhead. In an alternative embodiment of the deflection plate, the through holes in the plate are precisely adjusted to the output holes of the recording head, but in this embodiment the through holes are specially configured so that the path of the satellite drop is diverted, for example, through the through holes with an S-shaped curved profile or specially designed otherwise. As for the design of the recording head with the plate, reference is made to the patents US 7,093,915 B2 and US 2003/0179258 A1 cited above.

In another preferred embodiment of the present invention a specific color is assigned to a predetermined angle, under which a satellite pixel is generated with respect to the main pixel to which it is associated. According to this embodiment, the main pixel and the associated satellite pixel are generated under this angle a and printed in this color associated with the angle a. This provides an additional security feature. This security feature consists in that there is a certain color assigned to a specific orientation of a satellite pixel with respect to the main pixel with which it is associated, and in that the main pixel and satellite are also printed in this color. There is a forgery or adulteration when a pixel so configured is not printed in the assigned color.

According to a further development of this embodiment of the present invention, a specific color can be assigned respectively to several predetermined angles a1, as, ..., an, ..., under which satellite pixels are generated with respect to to the main pixels with which they are associated. In this case the main pixels and their respective satellite pixels are generated under the corresponding angle an and are printed in this color assigned to the angle an.

For example, a pattern may include printed pixels that in relation to the associated major pixels appear at the 1 o'clock, 4 o'clock, 7 o'clock, and 10 o'clock positions on the printed surface. The specific orientations are assigned specific colors, such as those of the CMYK color space, for example, to the position of 1 o'clock the yellow color, to the position of 4 o'clock the magenta color, to the position of the 7 o'clock the color cyan and the position of 10 o'clock the color "black". If a document contains a representation based on pixels composed respectively of main pixels and satellites, where at least there are some loose pixels printed in a color that does not correspond to the relative orientation of the satellite pixels with respect to their associated main pixels, such as pixels with satellite pixels in the position of 7 o'clock printed in yellow, it turns out that the document with this representation is false or falsified.

According to a preferred embodiment of the present invention, at each of the predetermined angles a1, as, ..., an, ..., under which satellite pixels are generated with respect to the main pixels with which they are associated, a given surface can be assigned to the stratified composite. In this case the main pixels and the associated satellite pixels are generated under the respective angle an and on this surface assigned to the angle an.

For example, a pattern is distributed over several, for example four, surfaces of the respective polymer layers of the layered composite, which are superimposed after the joining of said layers, resulting in the representation. The pixels are printed on each surface with an orientation of the satellite pixels different from that of the corresponding main pixels, for example, on the first surface with satellite pixels at the 2 o'clock position, on the second surface at the position of 5 o'clock, on the third surface at the 8 o'clock position and on the fourth surface at the 11 o'clock position. If a document with this color-based pixel coding results in an incorrect assignment, it can be verified that the document is counterfeit or adulterated. This embodiment is particularly advantageous when the different surfaces are separated from each other by at least one layer of the compound, which makes it possible to distinguish each layer thereof.

In another preferred embodiment of the present invention, the reproductions made in the previous embodiment on the different surfaces can be printed in different colors. For example, several reproductions printed on the different surfaces may be color extracts of a colored image. In this case each color extract can be assigned a different orientation of the satellite pixels and a color code, according to the previous embodiments of the present invention.

Accordingly, said security features can be formed in principle on a single surface of the layered composite, or by several layers printed on different surfaces of the layered composite, so that these various surfaces are preferably separated and therefore distanced from each other by at least one polymer layer, and the layers of the laminated composite are joined so that the reproductions of all the printed layers, such as for example the color extracts of a photo, on the different surfaces are preferably superimposed accurately. In this case, polymer layers which are colorless and transparent are preferably used in order to be able to see from the outside the layers printed on the different layers of the layered composite.

For example, a suitable reproduction can be made, for example, of a passport photo, with satellite pixels oriented in a predetermined way with respect to the main associated pixels, dividing the reproduction as in chessboard tables and distributing them over the different surfaces of the stratified composite, such that they are alternately on successive surfaces. For example, frames can be distributed on two surfaces so that the first, third, fifth ... frames of a row of successive frames in the reproduction are on a first surface and the second, fourth, sixth, ... frames in a second surface, and the respective frames of other rows can be distributed on both surfaces in the same way, for example, displaced with respect to the adjacent rows. As the different surfaces on which the partial images are located are spaced apart from each other, the result is a spatial impression of the reproduction, the deeper the more printed layers of this reproduction are included in the different surfaces of the stratified composite. In addition, various color extracts of the reproduction can also be prepared and printed on different surfaces of the layered composite, so that by joining the individual polymer layers to form the layered composite the desired color reproduction results.

According to another preferred embodiment of the present invention, an additional printed layer can be applied, which is printed on a modified surface in partial areas, for example, in the form of a grid or another type of pattern. In this embodiment, the modification of the surface by means of a grid or another pattern is done by varying the surface energy of the surface that must be gridded in partial areas corresponding to the grid, so that the liquid ink does not wet the surface of these areas. partial This variation of the surface energy may consist of hydrophilizing a surface that would otherwise be hydrophobic or hydrophobic, a surface that would otherwise be hydrophilic. The applications of these surface modifications are described, for example, in WO 03056641 A1 and in the document "Microcontact Printing of Self-Assembled Monolayers" Surface Science, The Whitesides Research Group, accessed 02 / 08/2008 at http: // gmwgroup. harvard.edu/research_surfacescience.html. Once the surface is gridded, a visible image is printed on it over the printing area where the surface is partially modified. This creates a primary visible image and also a latent secondary image in the same printing area. The pattern of the partial areas whose surface energy has been modified is superimposed on the printed image of the visible primary impression: where there are modified surface areas, the material of the layered composite does not absorb any printing ink. Thus, for example, circular surfaces of the grid printed by inkjet are delimited, for example laterally, or these areas are completely suppressed during the printing process if they are in the modified partial areas. This is because the printing ink that impacts these partial areas is repelled from them by the altered surface energy and flows to the adjacent partial areas of the surface where the surface energy has not changed and the printing ink adheres.

In the case where the polymeric layers are not water-wettable and the ink composition is substantially immiscible with water, for example, if the polymeric layer is polycarbonate, the partial areas of the surfaces in the printing areas can be modified by increasing its hydrophilicity, that is, its tendency to be moisturized by water. This ensures that the modified areas do not absorb the ink, but repel it during the printing process. Hydrophilization can be carried out, for example, by applying reagents on the partial areas of the surfaces to be modified.

For example, the surface can be printed in a grid pattern by means of a silicone buffer that reproduces said grid in the microcontact printing process. Alternatively, an aerosol writing method may be used, for example, the M3D® method of Optomec®, USA. It is an application method without template in which the reagents are sprayed with a spray, the resulting aerosol is transported by a first stream of gas to a nozzle and is projected by a second stream of gas directed to the partial areas of the surface.

For printing, the surface can be contacted with reagents that react with the surface material and hydrophilize it. Said hydrophilic reagents may in particular be compounds having at least one group reactive with the material of the polymer layers to be modified and at least one hydrophilic group. There may be spacer groups between the reactive groups and the hydrophilic groups. The reactive groups can be selected, inter alia, from the group consisting of carboxylic acid chlorides, carboxylic acid anhydrides, oxirane and phthalimide. Said reagents are especially suitable for modifying polycarbonate polymer layer surfaces, which contain -O- (C = O) -O- groups to which these reactive groups can be attached by nucleophilic substitution, so that the hydrophilic reagents are chemically bonded. It must be recognized that other nucleophilic reagents capable of forming a chemical bond with the polycarbonate can also be used in principle. For the chemical bonding of the hydrophilic reagents to the partial areas of the surface, suitable reaction conditions, which are known to those skilled in the field of organic synthesis, must be met, whereby the appropriate conditions can be selected. Alternatively, the partial areas of the surface that must be modified can carry a hydrophilic coating, such as a paste or a hydrophilic dispersion. To promote the adhesion of the paste or dispersion to the hydrophobic surface, the paste or dispersion contains, for example, a surfactant.

In contrast, the hydrophilic surfaces are hydrophobicized, for example, by fluorination or siliconization, for example by applying a hydrophobic layer carrying parts of fluorinated binders. Again, the structuring to produce the hydrophobic partial areas can be performed with a buffer according to the microcontact printing method or by a controlled drip printing method or by a photolithographic process. The polycarbonate layers can also be hydrophobic.

For example, this variant of the embodiment can produce printed pixels of rhombic, triangular, square or hexagonal shape and also of different size. Of course, printed pixels of different shape and / or size may also be assigned a color by this crosslinking, for example, cyan-colored triangular printed pixels, magenta square-printed pixels, yellow hexagonal printed pixels, and pixels rhombic printed in black. Alternatively, instead of crosslinking, any other pattern can also be generated as a latent and visible secondary image that overlaps the primary visible image, for example guilloches.

In a variant of the embodiment, the security feature formed by the primary visible image and the secondary latent visible pattern can be generated in a printing area other than the printing area where the security feature of the present invention is generated. by pixels printed with satellite pixels. In this case, the two printing areas can preferably be on surfaces of the laminated compound, separated from one another by at least one of the layers of said compound. In addition, these two printing areas may overlap, at least in part, so that the overlapping partial images form a common reproduction, such as a passport photo. In this case there are different security features represented in the individual partial images: on the one hand, in a first printing area, the security feature formed by additional satellite pixels to the associated main pixels and, in a second printing area, the safety characteristic due to the modification of the partial areas of the surfaces.

In another variant of the embodiment, the generation of security features according to the present invention through the production of satellite pixels in addition to the main pixels can also be combined with the previous additional variant of the execution form, according to which the surface it is modified in partial areas of the same area of printing and therefore on the same surface of a polymeric layer. In this case, if the primary visible image should be printed with satellites, it is convenient that the secondary latent visible information produces a surface with gridded areas larger than the areas of the printed pixels. In this case the satellites are visible in the main pixels, because the printed pixels are practically completely inside the gridded areas. Therefore, the presence of the grid and the formation of printed pixels with primary pixels and satellite constitute additional security features.

The above embodiments can also refer to a black and white representation, optionally with shades of gray, instead of color reproductions. These embodiments constitute additional security features to the security features according to the present invention and can be combined with them.

Likewise, it is convenient that the respective printed layers are arranged on internal layers of the stratified polymeric composite. This hinders or even prevents the falsification or adulteration of the printed layers that serve as security features.

However, in this case there is the other problem, mentioned above, that the usual data carriers in the form of a card can be delayed by manipulation with relative ease. In the event that a security feature has been applied by printing techniques on an inner layer of the layered composite, the problem of delamination can be solved so that the printed layers contain binders formed, at least substantially, by the same polymer than the layer material of the stratified composite. Then the risk of delaminations is practically excluded, because a monolithic composite of individual layers is formed when laminating. It is particularly preferred that the printed layers bear binders based on polycarbonate, if at least some of the layers of the composite also consist of polycarbonate. In the latter case, the printed layers are printed on internal layers of the laminated composite and, in particular, all the layers adjacent to the printed layers of the laminate are formed by polycarbonate.

For printing on composite polycarbonate layers, all common inks can be used in principle. It is preferred to use a preparation containing: A) 0.1 to 20% by weight of a binder with a polycarbonate derivative, B) up to 99.9% by weight of a solvent or mixture of preferably organic solvents, C ) 0 to 10% by weight of a dye or mixture of dyes (% by weight based on its dry mass), D) 0 to 10% by weight of a functional material or mixture of functional materials, E) 0 to 30% by weight weight of additives and / or auxiliary substances, or a mixture of such substances, so that the sum of the components A) to E) is always equal to 100% by weight, as a printing ink. Said polycarbonate derivatives are very compatible with polycarbonate materials, in particular with polycarbonates based on bisphenol A, such as for example Makrofol® films. In addition, the polycarbonate derivative used is stable at elevated temperatures and does not discolor in any way at normal lamination temperatures of up to 200 ° C and above, therefore the use of the low Tg materials described above is not necessary. In particular, the polycarbonate derivative may contain functional carbonate structural units of the formula (I)

where R ¹ and R ² , independently of each other, are hydrogen, halogen, especially chlorine or bromine, C 1 -C 8 alkyl, C 5 -C 6 cycloalkyl, C 6 -C 10 aryl, especially phenyl, and C 7 -C 12 aralkyl, especially phenyl -C1-C4 alkyl, especially benzyl;

m is an integer from 4 to 7, preferably 4 or 5; R ³ and R ⁴ can be chosen individually for each X e, independently of each other, they are hydrogen or C 1 -C 6 alkyl; X is carbon and n is an integer greater than 20, with the proviso that on at least one atom X, R ³ and R ⁴ are both alkyl. It is preferable that R ³ and R ⁴ are simultaneously alkyl in 1 or 2 X atoms, in particular only in one X atom. R ³ and R ⁴ can be in particular methyl. The X atoms in the a-position of the C-substituted diphenyl atom can not be substituted with dialkyl. The atoms of X in the position p with respect to C1 can be disubstituted with alkyl. Preferably m = 4 or 5. The polycarbonate derivative can be formed, for example, from monomers such as 4,4 '- (3,3,5-trimethylcyclohexane-1,1-diyl) diphenol, 4,4'. - (3,3-dimethylcyclohexane-1,1-diyl) diphenol or 4,4 '- (2,4,4-trimethylcyclopentan-1,1-diyl) diphenol. Said polycarbonate derivative can be prepared, for example, according to DE-A 3832396 mentioned in the literature, from diphenols of the formula (la). It is possible to use a diphenol of formula (la) to form homopolycarbonates and also different diphenols of formula (la) to form copolycarbonates (the meaning of radicals, groups and parameters as in formula I).

In addition, the diphenols of the formula (la) can also be mixed with other diphenols, for example with those of the formula (Ib)

HO-Z-OH (Ib),

to prepare macromolecular, thermoplastic and aromatic polycarbonate derivatives.

Other suitable diphenols of the formula (Ib) are those in which Z is an aromatic radical of 6 to 30 C atoms which may contain one or more aromatic nuclei, be substituted and contain aliphatic or cycloaliphatic radicals different from those of the formula (Ib). Ia) or heteroatoms as bridge members. Examples of the diphenols of the formula (Ib) are: hydroquinone, resorcin, dihydroxydiphenyls, bi- (hydroxyphenyl) -alkanes, bis- (hydroxyphenyl) -cycloalkanes, bis- (hydroxyphenyl) -sulfides, bis- (hydroxyphenyl) - ethers, bis- (hydroxyphenyl) -ketones, bis- (hydroxyphenyl) -sulfones, bis- (hydroxyphenyl) -sulphoxides, a, a'-bis- (hydroxyphenyl) -diisopropylbenzenes and their compounds with the alkyl-substituted nuclei and halogens. These and other suitable diphenols are described, for example, in US-A 3,028,365, US-A 2,999,835, US-A 3,148,172, US-A 3,275,601, US-A 2,991,273, US-A 3,271,367, US-A 3,062,781, US-A. 2,970,131, US-A 2,999,846, DE-A 1570703, DE-A 2063 050, DE-A 2063052, DE-A 2211 956, FR-A 1561 518 and in H. Schnell in: Chemistry and Physics of Polycarbonates [Chemistry and Physics of polycarbonates], Interscience Publishers, New York 1964. Other preferred diphenols are for example: 4,4'-dihydroxydiphenyl, 2,2-bis (4-hydroxyphenyl) -propane, 2,4-bis- (4-hydroxyphenyl) ) -2-methyl-butane, 1,1-bis- (4-hydroxyphenyl) -cyclohexane, a, a-bis- (4-hydroxyphenyl) -p-diisopropylbenzene, 2,2-bis- (3-methyl-4) -hydroxyphenyl) -propane, 2,2-bis- (3-chloro) -4-hydroxyphenyl) -propane, bis- (3,5-dimethyl-4-hydroxyphenyl) -methane, 2,2-bis- (3, 5-dimethyl-4-hydroxyphenyl) -propane, bis- (3,5-dimethyl-4-hydroxyphenyl) -sulfone, 2,4-bis- (3,5-dimethyl-4-hydroxyphenyl) -2-methylbutane, 1 , 1-bis- (3,5-dimethyl-4-hydroxyphenyl) -cyclohexane, a, a-bis- (3,5-d) imethyl-4-hydroxyphenyl) - p -diisopropylbenzene, 2,2-bis- (3,5-dichloro-4-hydroxyphenyl) -propane and 2,2-bis- (3,5-dibromo-4-hydroxyphenyl) - propane. Particularly preferred diphenols of the formula (Ib) are, for example, 2,2-bis- (4-hydroxyphenyl) -propane, 2,2-bis- (3,5-dimethyl-4-hydroxyphenyl) -propane, , 2-bis- (3,5-dichloro-4-hydroxyphenyl) -propane, 2,2-bis- (3,5-dibromo-4-hydroxyphenyl) -propane and 1,1-bis- (4-hydroxyphenyl) -cyclohexane. In particular, 2,2-bis- (4-hydroxyphenyl) -propane is preferred. The other diphenols can be used either individually or mixed. The molar ratio of diphenols of formula (Ia) to other diphenols of formula (Ib) optionally usable should be between 100 mol% (Ia) at 0 mol% (Ib) and 2 mol% (Ia) at 98 mol% (Ib). ), preferably between 100 mol% (Ia) at 0 mol% (Ib) and 10 mol% (Ia) at 90 mol% (Ib) and especially between 100 mol% (Ia) at 0 mol% (Ib) and 30% molar (Ia) at 70 mol% (Ib). The macromolecular polycarbonate derivatives of the diphenols of the formula (Ia), optionally in combination with other diphenols, can be prepared by the known polycarbonate production processes. The different diphenols can be linked both statistically and in blocks. The polycarbonate derivatives used can be branched in a known manner. If desired, the branching can be achieved in a known manner by condensing small amounts, preferably amounts of 0.05 to 2.0% by mole (with respect to the diphenols used), of trifunctional compounds or of higher functionality, in particular those with three or more. more phenolic hydroxyl groups. Some branching agents with three or more phenolic hydroxyl groups are phloroglucin, 4,6-dimethyl-2,4,6-tri- (4-hydroxyphenyl) -hepten-2,4,6-dimethyl-2,4,6- tris- (4-hydroxyphenyl) -heptane, 1,3,5-tri- (4-hydroxyphenyl) -benzene, 1,1,1-tri- (4-hydroxyphenyl) ethane, tri- (4-hydroxyphenyl) -phenyl-methane , 2,2-bis- [4,4-bis- (4-hydroxyphenyl) -cyclohexyl] -propane, 2,4-bis- (4-hydroxyphenyl-isopropyl) -phenol, 2,6-bis- (2- hydroxy) -5-methylbenzyl) -4-methylphenol, 2- (4-hydroxyphenyl) -2- (2,4-dihydroxyphenyl) -propane, hexa- [4- (4-hydroxyphenyl-isopropyl) -phenyl] -ortoterephthalate, tetra- (4-hydroxyphenyl) -methane, tetra- [4- (4-hydroxyphenyl-isopropyl) -phenoxy] -methane and 1,4-bis [4 ', 4 "-dihydroxytriphenyl) -methyl] -benzene. Some of the other trifunctional compounds are 2,4-dihydroxybenzoic acid, trimesic acid, cyanide chloride and 3,3-bis- (3-methyl-4-hydroxyphenyl) -2-oxo-2,3-dihydroindole. . As chain terminators for the known control of the molecular weight of the polycarbonate derivatives, functional compounds can be used in conventional concentrates. Suitable compounds for this are, for example, phenol, tert-butylphenols or other alkyl-substituted phenols. Small amounts of phenols of the formula (Ic) are particularly suitable for controlling the molecular weight.

where R represents a branched Cs and / or C9 alkyl radical. Preferably, in the alkyl radical R the proportion of protons of CH3 is between 47 and 89% and the proportion of protons of CH and CH2 between 53 and 11%; as well preferably, R is in the ortho position and / or in respect to the OH group, and particularly preferably the upper limit of the ortho portion is 20%. Chain terminators are generally used in amounts of 0.5 to 10, preferably 1.5 to 8 mol%, based on the diphenols used. The polycarbonate derivatives can preferably be prepared by the interfacial polycondensation method (see, H. Schnell in: Chemistry and Physics of Polycarbonates, Polymer Reviews, vol.9, page 33 et seq., Interscience Publ.1964), in the manner known . In this case, the diphenols of the formula (Ia) are dissolved in an aqueous alkaline phase. To prepare copolycarbonates with other diphenols, mixtures of diphenols of formula (Ia) and other diphenols are used, for example those of formula (Ib). To regulate the molecular weight, chain terminators can be added, eg of the formula (Ic). They are then reacted with phosgene by the interfacial condensation method, preferably in the presence of an inert organic phase in which the polycarbonate is dissolved. The reaction temperature is in the range of 0 ° C to 40 ° C. Branching agents optionally employed (preferably 0.05 to 2.0 mol%) can be incorporated together with the diphenols in the alkaline aqueous phase or dissolved in the organic solvent before phosgenation. In addition to the diphenols of the formula (Ia) and, if necessary, other diphenols (Ib), their mono- and / or bischloroformates can also be used, which are added dissolved in organic solvents. The amount of chain terminators and branching agents then depends on the molar amount of diphenolate radicals corresponding to formula (Ia) and optionally to formula (Ib); when chloroformates are used, the amount of phosgene can be lowered accordingly, as is known. Suitable organic solvents for chain terminators and, optionally, branching agents and chloroformates are, for example, methylene chloride, chlorobenzene and, in particular, mixtures of methylene chloride and chlorobenzene. If necessary, the chain terminators and the branching agents used can be dissolved in the same solvent. The organic phase for the interfacial polycondensation is, for example, methylene chloride, chlorobenzene and mixtures of methylene chloride and chlorobenzene. As an alkaline aqueous phase, for example, a solution of NaOH is used. The preparation of the polycarbonate derivatives by the interfacial polycondensation method can be catalyzed in a conventional manner by catalysts such as tertiary amines, in particular tertiary aliphatic amines such as tributylamine or triethylamine; the catalysts can be used in amounts of 0.05 to 10 mol% relative to the moles of diphenols used. The catalysts can be added before the start of the phosgenation or during or after it. The polycarbonate derivatives can be prepared by the known method in homogeneous phase, the so-called "pyridine process" and by the process known as melt transesterification, using, for example, diphenyl carbonate instead of phosgene. The polycarbonate derivatives can be linear or branched, and are homopolycarbonates or copolycarbonates which are based on the diphenols of the formula (Ia). The properties of the polycarbonate can be favorably varied by discretional composition with other diphenols, in particular with those of the formula (Ib). In these copolycarbonates the content of diphenols of the formula (Ia) is comprised between 100 mol% and 2 mol%, preferably between 100 mol% and 10 mol% and especially between 100 mol% and 30 mol% , with respect to 100 mol% of diphenol units contained in the polycarbonate derivatives. The polycarbonate derivative can be a copolymer containing and in particular consisting of M1 monomer units based on the formula (Ib), preferably bisphenol A, and M2 monomer units based on the geminally disubstituted dihydroxydiphenylcycloalkane, preferably the 4,4 '- (3 , 3,5-trimethylcyclohexane-1,1-diyl) diphenol, so that the molar ratio M2 / M1 is preferably greater than 0.3, in particular greater than 0.4, for example greater than 0.5. It is preferred that the polycarbonate derivative have an average (weight) molecular weight of at least 10,000, preferably from 20,000 to 300,000.

In principle, component B can be basically organic or aqueous. Substantially aqueous means that up to 20% by weight of component B) can be organic solvents. Substantially organic means that there may be up to 5% by weight of water in component B). Component B preferably contains or consists of a liquid aliphatic, cycloaliphatic and / or aromatic hydrocarbon, a liquid organic ester and / or a mixture of such substances. The organic solvents used are preferably halogen-free organic solvents. Particularly suitable are aliphatic, cycloaliphatic and aromatic hydrocarbons such as mesitylene, 1,2,4-trimethylbenzene, cumene and solvent naphtha, toluene, xylene, (organic) esters such as methyl acetate, ethyl acetate, butyl acetate, methoxypropyl acetate, ethyl 3-ethoxypropionate. Preferred are mesitylene, 1,2,4-trimethylbenzene, cumene and solvent naphtha, toluene, xylene, methyl acetate, ethyl acetate, methoxypropyl acetate, ethyl 3-ethoxypropionate. . Particular preference is given to mesitylene (1,3,5-trimethylbenzene), 1,2,4-trimethylbenzene, cumene (2-phenylpropane), solvent naphtha and ethyl 3-ethoxypropionate. A suitable solvent mixture has for example L1) 0 to 10% by weight, preferably 1 to 5% by weight, in particular 2 to 3% by weight of mesitylene, L2) to 50% by weight, preferably 25 to 50% by weight%, in particular 30 to 40% by weight of 1-methoxy-2-propanol acetate, L3) 0 to 20% by weight, preferably 1 to 20% by weight, in particular 7 to 15% by weight of 1 , 2,4-trimethylbenzene, L 4) 10 to 50% by weight, preferably 25 to 50% by weight, in particular 30 to 40% by weight of ethyl 3-ethoxypropionate, L 5) 0 to 10% by weight, preferably 0 , From 1 to 2% by weight, in particular from 0.05 to 0.5% by weight of cumene, and L6) 0 to 80% by weight, preferably 1 to 40% by weight, in particular from 15 to 25% by weight of Solvent naphtha, the sum of the components L1 to L6 being always equal to 100% by weight.

The preparation can contain in detail: A) 0.1 to 10% by weight, especially 0.5 to 5% by weight of a binder with a polycarbonate derivative based on a geminally disubstituted dihydroxydiphenylcycloalkane, B) 40 to 99.9 % by weight, in particular 45 to 99.5% by weight of an organic solvent or solvent mixture, C) 0.1 to 6% by weight, in particular 0.5 to 4% by weight of a dye or a mixture of dye, D) 0.001 to 6% by weight, in particular 0.1 to 4% by weight of a functional material or a mixture of functional materials, E) 0.1 to 30% by weight, in particular 1 to 20% by weight, weight of additives and / or auxiliary substances or of a mixture of such substances.

As component C, if the use of a colorant is foreseen, basically any dye or mixture of dyes is considered. All coloring substances are designated as dyes. This means that they can be both dyes (in the chapter "Dyes, General Survey [Dyes, overview]" of the Ullmann encyclopedia of industrial chemistry, 2007 electronic edition, Wiley editorial, there is a general summary of dyes) as pigments (in the chapter on organic and inorganic pigments of the Ullmann encyclopedia of industrial chemistry, electronic edition of 2007, editorial Wiley, there is a general summary of them). The dyes must be soluble or (stable) dispersible or suspended in the solvents of component B. Furthermore, it is convenient that the dye maintains the color at a temperature of 160 ° C and more for a period of more than 5 min. It is also possible that the colorant undergoes a predetermined and reproducible color change under the process conditions and is selected accordingly. In addition to the thermal stability, the pigments must be as finely divided as possible. This means in practice that, for an ink jet print, the particle size must not exceed 1.0 μm, otherwise the print head is clogged. In general, the solid pigments of nanometric particle size and the dissolved dyes have given good results. The dyes can be cationic, anionic or even neutral. Examples of dyes which can be used in inkjet printing include only: gloss black CI No. 28440, eriochrome black CI No. 14645, direct dark black E CI No. 30235, genuine black salt B CI No. 37245, Genuine black salt K CI n ° 37190, black Sudan HB CI 26150, black naphthalene CI No. 20470, black liquid Bayscript®, basic black CI 11, basic blue CI 154, turquoise Cartasol® KZL liquid, turquoise Cartasol® K-RL liquid (basic blue CI 140), blue Cartasol K5R liquid. Also suitable are, for example, the commercially available dyes Hostafine® black TS liquid (sold by Clariant GmbH Germany), Bayscript® black liquid (CI mixture, sold by Bayer AG Germany), Cartasol® black liquid MG (basic black CI 11, registered trademark of Clariant GmbH Germany), Flexonyl® black PR 100 (E CI No. 30235, marketed by Hoechst AG), rhodamine B, Cartasol® orange K3 GL, Cartasol® yellow K4 GL, Cartasol® K GL or Cartasol® red K -3B. In addition, anthraquinone, azo, quinophthalone, coumarin, methine, perinone and / or pyrazole, available eg under the trademark Macrolex®, can be used as soluble dyes. Other suitable colorants are described in the chapter "Colorants Used in Ink Jet Inks" of the Ullmann encyclopedia of industrial chemistry, electronic edition of 2007, Wiley editorial. The well soluble dyes are optimally integrated into the matrix or binder of the printed layer. The dyes can be added directly as a dye or pigment, or in the form of a paste, a mixture of dye and pigment together with another binder. This additional binder must be chemically compatible with the other components of the preparation. If said paste is used as a dye, the indicated amount of component B refers to the dye without the other components of the dough. These other components of the paste should then be included in the component E. With the use of said pigments as colors of the cyan-magenta-yellow scale and also preferably of carbon black, images can be obtained with tinted shades.

Component D includes substances that, with the help of technical means, are directly detectable by the human eye or by the use of appropriate detectors. These are materials known to the specialist (see also van Renesse in: Optical document security , 3rd edition, Artech House., 2005) which are used to protect documents of value and security. These materials include luminescent substances (dyes or pigments, organic or inorganic) such as, for example, photoluminophores, electroluminophores, anti-Stokes luminophores, fluorophores, and also magnetizable, photoacoustically addressable or piezoelectric materials. In addition, materials with Raman effect or Raman effect amplifiers, as well as so-called barcode materials, can be used. The preferred criteria for solubility in component B or particle sizes <1 μm in pigmented systems also apply, as well as thermal stability at temperatures> 160 ° C in the embodiments of component C. Functional materials can be incorporated directly or by means of a paste, that is to say, a mixture with another binder, which then forms part of the component E, or the binder used in component A.

The E component of inkjet printing inks comprises usually prepared materials, such as defoamers, fixing agents, wetting agents, surfactants, fluidizers, driers, catalysts, (photo) stabilizers, preservatives, biocides, organic viscosity regulating polymers. and buffer systems. Suitable fixing agents are common binding salts, for example, sodium lactate. As biocides, all commercially available preservatives used for inks can be used. Some examples are Proxel® GXL and Parmetol® A26. Suitable surfactants are all commercially available surfactants that are used for inks. Amphoteric or nonionic surfactants are preferred. Of course it is also possible to use special anionic or cationic surfactants that do not alter the characteristics of the dye. Examples of suitable surfactants are betaines and ethoxylated diols, for example, the products of the Surfynol® and Tergitol® series. For ink jet printing, the amount of surfactants is especially chosen, for example, so that the surface tension of the ink is in the range of 10 to 60 mN / m, preferably 20 to 45 mN / m, measured at 25 ° C. A buffer system can be established that stabilizes the pH in the range of 2.5 to 8.5, especially in the range of 5 to 8. Suitable buffer systems are those of lithium acetate, borate buffer, triethanolamine or acetic acid / sodium acetate. In particular, a buffer system is considered necessary in the case of a substantially aqueous component B. To adjust the viscosity of the ink (optionally soluble in water), polymers are provided, including all those that are suitable for conventional ink formulations. Examples include water-soluble starches, in particular those having an average molecular weight of 3,000 to 7,000, polyvinylpyrrolidone, in particular that having an average molecular weight of 25,000 to 250,000, polyvinyl alcohol, in particular which has an average molecular weight of 10,000 to 20,000, xanthan gum, carboxymethylcellulose, block copolymers of ethylene oxide / propylene oxide, in particular which have an average molecular weight of 1,000 to 8,000. An example of such block copolymers is the Pluronic® product line. The ratio of biocide to total amount of ink may be in the range of 0 to 0.5% by weight, preferably 0.1 to 0.3% by weight. The proportion of surfactant to the total amount of ink may be in the range of 0 to 0.2% by weight. The proportion of fixing agents with respect to the total amount of ink may be in the range of 0 to 1% by weight, preferably 0.1 to 0.5% by weight. Auxiliary substances also include other components, such as acetic acid, formic acid or N-methyl-pyrrolidone or other polymers used in the dye solution or paste. As for substances suitable as component E, it is referred as a supplement, for example, to the chapter "Paints and coatings", section "Additives for paints" of the Ullmann Encyclopedia of industrial chemistry, 2007 electronic edition, Wiley editorial.

The ink composition described above is suitable, above all, for ink jet printing, but is also applicable to any other printing technique, provided that the proportion of the individual components is adapted to the use. In this context it is advantageous that said composition contains a polycarbonate derivative as a binder, if the polymeric layers of the compound are also polycarbonate.

The present invention is described below by way of non-limiting examples.

Fig. 1 shows typical sets of main pixel-satellite pixel;

Fig. 2 shows different variants of main pixels with satellite pixels;

Fig. 3 shows a schematic representation of an ink jet recording head on a printing medium, and the resulting pixels formed by main pixels and satellite pixels;

Fig. 4 shows a schematic representation of a nozzle plate in a cross-section ink jet print head;

Fig. 5 shows a schematic representation of printed pixels constituted by main pixels and satellite pixels;

Fig. 6 shows a schematic representation of printed pixels, consisting of principal pixels and satellite pixels, on which a latent visible image formed by a rhombic grid (Figure 6C) has been superimposed.

In the figures, the same reference numbers designate respectively the same elements.

In fig. 1 shows two typical sets of pixel main-pixel satellite. Each satellite pixel B is assigned to the corresponding main pixel A and is in a defined relative position with respect to the main pixel A, in this case approximately in the "7 o'clock position". On the left side of this figure the satellite pixel B is not so far from the main pixel A so that both pixels are separated from each other. On the right side of the figure both pixels are separated from each other. This can be achieved, respectively, by adjusting the deflection when ejecting the ink droplets from the print head. In fig. 2 shows different forms of execution of matrices of main pixels and associated satellite pixels.

Figure 3 shows schematically a print head 1 which moves in a printing direction 2 on a printing medium 3, for example, a polymeric sheet. From the ink outlet orifices 4 in the lower part of the recording head 1, ink droplets appear which first extend and then divide into a main drop and a satellite drop. The main drop is ejected following the normal to the plane formed by the lower part of the recording head 1, in which the discharge holes 4 are located. The main drop path is marked as 5. The main drop forms the main pixel 11. The satellite drop is ejected onto the polymeric sheet 3 in a direction deviated from the normal direction. This path is marked as 6. The satellite drop forms the satellite pixel 12. The angle of deviation of the satellite drop with respect to a plane defined by the printing direction 2 and the main pixel 11 is marked as p. The angle at which the satellite pixel 12 appears on the polymeric sheet 3 in relation to the main pixel 11, with respect to the printing direction 2 is marked as a.

In fig. 4 a deflector device 7 is schematically shown in a droplet generating device 8 of a recording head 1. The droplet generating device 8 has outlet holes 4. The baffle device 7 has channels 9 whose inlet holes 10 are aligned with the outlet orifices 4 of the droplet generating device 8. The channels 9 are S-shaped and, therefore, deviate the satellite drops, while the deviation of the trajectories of the main droplets is negligible. In the example shown, the satellite drops are diverted to the left.

Satellite drops are diverted in the example shown on the left.

To produce a pattern by ink jet printing on a polycarbonate sheet, the following ink compositions were prepared:

Example 1: Preparation of polycarbonate derivatives as a binder for the composition an ink

In an inert gas atmosphere, 149.0 g (0.65 mol) of bisphenol A (2,2-bis- (4-hydroxyphenyl) -propane, 107.9 g (0.35 mol) of 1,1-bis- (4-hydroxyphenyl) -3,3,5-trimethylcyclohexane, 336.6 g (6 moles) of KOH and 2700 g of water, then a solution of 1.88 g of phenol is added in 2500 ml of methylene chloride, in the solution well With stirring, 198 g (2 moles) of phosgene are introduced at a pH of 13 to 14 and 21 to 25 ° C. Then 1 ml of ethylpiperidine is added and the mixture is stirred for another 45 minutes. The free aqueous phase of bisphenolate is separated, the organic phase is washed with water until neutral pH and freed of the solvent, after acidifying it with phosphoric acid. The polycarbonate derivative has a relative solution viscosity of 1.263. The glass transition temperature is 183 ° C (determined by DSC).

Example 2: Obtaining a liquid preparation suitable for an inkjet printing dye

A liquid preparation is obtained starting from 17.5 parts by weight of the polycarbonate derivative of Example 1 and 82.5 parts by weight of a mixture of solvents according to Table I (data in% by weight with respect to the solvent mixture).

Table I

A colorless and highly viscous solution having a viscosity of 800 mPas in solution at room temperature is obtained.

Example 3: Preparation of an ink jet printing dye used according to the present invention In a 50 ml wide neck glass container, 10 g of polycarbonate solution of example 1 and 32.5 are homogenized with a magnetic stirrer. g of the solvent mixture of example 2 (4% PC solution). A colorless, slightly viscous solution having a viscosity of 5.02 mPas in solution at 20 ° C is obtained.

The obtained polycarbonate solution is further mixed with about 2% of black pigment 28. The result is an ink with which black and white images can be printed on polycarbonate sheets. With a similar addition of other pigments or dyes monochromatic and / or color inks can be prepared respectively.

During a process of joining a substrate layer printed by a pixel pattern and another layer of superimposed substrate, the resolution of the printed pattern with the ink practically does not vary. This means that the pixel pattern also retains practically the same resolution after lamination.

On the other hand, an optical examination of the compound does not recognize any detectable phase limit. The compound is presented as a monolithic block, which also excellently resists delamination attempts.

With this black ink a pixel pattern is printed on a polycarbonate sheet by an ink jet printer with a modified head as shown in FIG. 4. The result is the pixel matrix shown in Figure 5. Each of the printed pixels is bimodal and consists of a larger main pixel and a smaller satellite pixel. The satellite pixel appears with respect to the main pixel to which it is associated at an angle α of approximately 60 ° with respect to the transport direction (defined from right to left by the rows of printed pixels).

Example 4: formation of satellite pixels in a pattern created by ink jet printing on previously hydrophobic surfaces in gridded structures.

To create a multicolored passport photo of a person, several extracts of the photo are made in magenta, cyan, yellow and black.

In a first printing process, the main pixels are printed with the corresponding satellite pixels on a first sheet of polycarbonate (Figure 6A).

Then another polycarbonate sheet was hydrophobicized, first in a printing area with a rhombic pattern. The diamonds are so large that you can then print completely at least one pixel inside. For this, the polycarbonate sheet is printed by the dry offset method, the so-called Toray process, with a UV-curable ink invisible to the human eye. This ink carries silicone, without dye, and optionally fluorinated binder proportions. For printing, a motif in the form of rhombic lines is copied onto a printing plate and printed on a PC sheet. As a result, the rhombic lines invisible to the human eye represented in FIG. 6B.

Then a yellow extract of the passport photo of the person is printed by ink jet on the polycarbonate sheet in the printing area hydrophobicized in partial areas. The composition of the ink used for this corresponds to that of Example 3. In this case each pixel is printed in the form of a main pixel and a satellite pixel that appears at an angle to the main pixel, against the printing direction. This angle a is indicated by the position of 1 o'clock. Where the diamond pattern is, the pixels can not be printed (Fig. 6C).

Other extracts of the passport photo in yellow, cyan and magenta are printed in the same way on polycarbonate sheets previously hydrophobic with rhombic structure by means of inkjet printing in a printing area corresponding to the printing area of the first polycarbonate sheet . The ink compositions are those of Example 3. However, in place of the black pigment 28, suitable dyes are used to print the yellow, cyan and magenta extracts. The ink jet print head is adjusted in all three cases so that the satellite drops are ejected at an exit angle p t 0 opposite a plane defined by the printing direction and the main pixels. With the use of suitable baffles, images similar to those of FIG. 6C, although the orientation of the satellite pixels with respect to the main pixels is different. In each color extract, another angle is established at which the satellite drops impact on the polycarbonate sheet with respect to the main drops, against the flight path of the main drops: the position of the satellite pixels of the yellow extract is adjusts to that of the main pixels at the 4 o'clock position. The position of the satellite pixels of the cyan color is adjusted with respect to that of the main pixels at the 7 o'clock position and the position of the satellite pixels of the magenta color is adjusted with respect to that of the main pixels in the position of 10 o'clock. In any case, the satellite drops are partially recognizable and partially suppressed by the rhombic patterns.

Then the sheets are stacked and laminated. A monolithic sheet compound is formed. The color extracts printed on the layered composite can be assigned to the individual layers of the composite: the black colored extract can then be recognized by the fact that it contains satellite pixels at the 1 o'clock position; the yellow extract can then be recognized by the fact that it contains satellite pixels at the 4 o'clock position; the cyan color extract can then be recognized by the fact that it contains satellite pixels at the 7 o'clock position and the magenta extract can then be recognized by the fact that it contains satellite pixels at the 10 o'clock position.

It should be understood that the examples and embodiments described herein are for illustrative purposes only, and that various modifications and changes in the examples and embodiments, as well as combinations of the features described in this patent application, are apparent to a specialist. .

Claims (14)

A stratified polymeric composite for a security and / or value document comprising at least two layers of polymer bonded cohesively to each other, wherein at least on one surface of at least one of the polymer layers there are applied printed layers formed respectively by pixels in a printing area, wherein the printed layer is generated by an ink jet recording, characterized in that each printing pixel consists of a main pixel and of at least one satellite pixel associated with the main pixel, and because the presence of pixels Satellite in addition to the main pixels to which they are associated represents a security feature of the security and / or value document. 2. A stratified polymeric composite for a security and / or value document according to claim 1, characterized in that the printed layer reproduces a personalized and / or individualized characteristic. Layered polymeric composite for a security and / or value document according to one of the preceding claims, characterized in that the printed layer is generated on one of the surfaces by an ink jet recording head, and because each satellite pixel is generates on the surface with respect to a corresponding main pixel to which it is associated, with a predetermined orientation with respect to the respective main pixel. Layered polymeric composite for a security and / or value document according to claim 3, characterized in that each satellite pixel is generated with respect to the corresponding main pixel to which it is associated, at a predetermined angle a with a line of union of main pixels Adjacent printed on the surface, being at 0 ° and at 180 °. Layered polymeric composite for a security and / or value document according to one of the preceding claims, characterized in that the respective printed layers are disposed on internal surfaces of the layers of the stratified polymeric composite. Method for producing a stratified polymeric compound intended for a security and / or value document comprising at least two polymer layers joined cohesively to each other, which consists of the following process steps: preparation of the polymer layers for the composite stratified polymer, forming the respective pixel layers printed on at least one surface of at least one of the polymer layers in a printing area and bonding the polymer layers together, each printed layer generating by ink jet printing, characterized because the printed pixels consist respectively of a main pixel and at least one satellite pixel associated with the main pixel and because the presence of satellite pixels in addition to the main pixels to which they are associated constitutes a security feature of the security document and / or of the security document. value. Method for producing a stratified polymeric compound intended for a security and / or value document according to claim 6, characterized in that the printed layer is incorporated in the form of a personalized or individualized characteristic. 8. Method for producing a layered polymeric composite for a security and / or value document according to one of claims 6 - 7, characterized in that the printed layer is generated by an ink jet recording head on one of the surfaces and because each satellite pixel is generated on the surface, with respect to the main pixel to which it is associated, forming a predetermined angle with respect to the direction in which the print head and the surface move relative to each other. 9. Method for manufacturing a layered polymeric compound for a security and / or value document according to claim 8, characterized in that , independently of the direction in which the printhead and the surface move relative to each other, each satellite pixel it is generated with respect to the main pixel to which it is associated, forming a predetermined angle with respect to a line joining adjacent main pixels printed on the surface. Method for producing a laminated polymeric compound intended for a security and / or value document according to one of claims 8 - 9, characterized in that the angle α is established by adjusting a device provided in the ink jet recording head for divert the drops of satellite ink to the exit of the head or so that the device deflector of the drops of satellite ink at the exit of the head is a device provided with through holes, adjacent to the exit holes of the printhead. Method for producing a stratified polymeric compound intended for a security and / or value document according to claim 10, characterized in that the deflector device for the drops of satellite ink at the exit of the printhead is adjusted and / or configured so that the liquid ink forming the satellite pixels leaves the orifices of the head at an angle p relative to a plane defined by the corresponding main pixel and the direction in which the printhead and the surface move relative to each other. Method for producing a layered polymeric compound for a security and / or value document according to one of claims 6 - 11, characterized in that the respective printed layers of the composite polymeric laminates are disposed on internal surfaces of the polymeric layers of the stratified polymeric composite. 13. Security and / or value document containing a stratified polymeric compound according to one of claims 1-5. 14. Use of the security and / or value document according to claim 13 as an identity document, passport, credit card, bank card, cash payment card, customer card, Visa card, identification card or driver's license. drive.