METHOD FOR PRODUCING PIGMENTS WITH PREDEFINED INNER AND / OR OUTER CONTOUR

Description

[0001] The invention relates to a process for producing pigments with a predetermined contour.

[0002] Data storage media, such as valuables or identification documents, as well as other valuable items such as branded goods, are often provided with effect pigments for security purposes. These pigments allow verification of the data storage medium's authenticity and also serve as protection against unauthorized reproduction. Effect pigments can, for example, be integrated into the data storage medium's substrate or applied to the data storage medium's substrate. Pigments with a predefined outer contour are a common form of such effect pigments.

[0003] Effect pigments can be produced, among other things, by coating a substrate, then removing the coating from the substrate and grinding it into small fragments. These fragments can be dispersed as pigments in a binder and then printed. Due to the manufacturing process, neither the shape nor the size of the pigments are precisely defined.

[0004] However, various methods are also known for creating pigments with a predetermined outer contour.

[0005] For example, WO 2005 / 017048 A2 proposes embossing the carrier material according to the desired pigment contour and applying the coating to the embossed carrier material. The coating is removed from the carrier layer and broken down into pigments by grinding and sieving, which can have a diameter of 5 to 100 µm. In EP 2 062 947 A1, which proposes an improved embossed structure to define the pigment contour, the removed layer is also broken down into pigments.

[0006] In alternative solutions, the pigment layers are structured into pigments by lasering or etching.

[0007] The invention is based on the object of providing a flexible but cost-effective production process for pigments, which in particular allows the production of pigments with more complex outer contours.

[0008] This object is solved by the features of independent claim 1. Further developments of the invention are the subject of the dependent claims.

[0009] A process for producing pigments with a predetermined contour comprises the following steps: Creating a pigment layer on a starting substrate; detaching it from the starting substrate; and structuring the pigment layer into a plurality of pigments.

[0010] In this case, the pigment layer is brought into contact with an intermediate substrate. The pigment layer adheres to the intermediate substrate at least in sections. The intermediate substrate and the original substrate are then separated again.

[0011] In particular, the predetermined contour of the pigment can include an outer contour (outline of the pigment). The outer contour of the pigment defines the pigment. Likewise, the predetermined contour of the pigment can have an inner contour. The inner contour of the pigment defines an opening in the pigment. The process makes it possible to produce pigments with a more complex outer contour than conventional breaking of the pigment layer. Furthermore, for the first time, pigments with an inner contour—i.e., with a circumferential breaking edge that defines an opening within the pigment—can be produced by breaking.

[0012] Through contact with the intermediate substrate, the pigments (or pigment sections of the pigment layer) are protected against breakage during the dissolving and / or structuring step.

[0013] Preferably, the pigment layer is structured into the multitude of pigments by separating the intermediate substrate and the starting substrate. During separation, the pigment layer breaks into the multitude of pigments with a predetermined contour.

[0014] With the present method, preferably at least 2,000 pigments, particularly preferably at least 5,000 pigments, and further preferably more than 10,000 pigments, are simultaneously structured (or broken out) from the pigment layer in the separation step. This number is preferably structured simultaneously along a separation line.

[0015] In particular, the pigment layer comprises pigment sections and residual sections. The pigment sections have the contour of the pigments. The pigment sections are spaced apart from one another, in particular by the residual section. The residual sections have a contour that is inverse to that of the pigment sections. Optionally, the residual sections can be connected to one another. During the separation step, the pigment layer breaks, and either the pigment layer sections or the residual sections are detached from the starting substrate. The other sections—i.e., the residual sections or the pigment layer sections, respectively—remain on the starting substrate even after separation.

[0016] The present process allows the production of pigments with a specified contour in high purity. The degree of purity can be expressed as a percentage by weight. The pigments with a specified contour constitute more than 90%, preferably more than 95%, of the weight mass, including the pigments and impurities, which are formed in particular by fragments of the pigment layer and only to a small extent by pigments with damaged contours. Contamination with fragments is particularly avoided because the remaining sections of the pigment layer (or the pigment sections) remain attached to the original substrate.

[0017] In the preferred embodiment, the pigments (or the pigment layer sections of the pigment layer) are released from the starting substrate by the separation step. The pigments are transferred from the starting substrate to the intermediate substrate and are protected by the intermediate substrate at the time of breaking. The pigments are then released from the intermediate substrate.

[0018] In another embodiment, the plurality of pigments (or the pigment layer sections of the pigment layer) remain on the starting substrate after separation. The pigments are then detached from the starting substrate. In the separation step, the pigment layer breaks, and the remaining sections are detached from the starting substrate.

[0019] Only as an alternative to the aforementioned embodiments, the pigment layer is structured prior to the separation step. In the separation step, either the pigment layer sections or the remaining sections are separated from the starting substrate from the already structured pigment layer. The pigments are protected by the intermediate substrate (and the starting substrate) at the time of separation.

[0020] A relief structure is created in the starting substrate and / or the intermediate substrate, which defines the contour of the pigments. The relief structure comprises, in particular, raised sections in which the pigment layer comes into contact with and adheres to an adhesive layer (of the other substrate), and recessed sections which prevent contact between the pigment layer and this adhesive layer. Either the recesses or the elevations are provided with the contour of the pigments. The relief structure can be created by embossing, lasering, or etching. Since the relief structure (and / or an adhesion structure explained below) does not yet result in individual pigments, this is also referred to herein as pre-structuring. The height of the relief structure is preferably greater than the height of the pigment layer.In particular, the height of the relief structure (the difference between the flat elevations and depressions) is adapted to the height of the pigment layer and / or the adhesive layer, particularly its height and viscosity. This adaptation ensures that the pigment layer adheres selectively to the intermediate substrate only in the raised sections (or adheres more strongly than to the original substrate). The structuring of the pigment layer into individual pigments is achieved by breaking the pigment layer with the contours defined by the pre-structuring and predefined for the pigments.

[0021] The starting substrate can be provided with the relief structure—preferably before, but alternatively also after, the pigment layer has been created on the starting substrate. The relief structure can be created in particular by embossing, preferably by embossing into a curable (lacquer) layer, which is cured after embossing, for example, using UV light. In the starting substrate without a pigment layer, the relief structure can alternatively also be created by etching or lasering. Depending on the relief structure, the pigment layer on the pre-structured starting substrate comprises pigment sections and residual sections. After contact with the intermediate substrate, the raised sections adhere to the adhesive layer of the intermediate substrate.Preferably, the pigment portions are the raised portions which - are stabilized by adhesion to the intermediate substrate and - break upon separation of the substrates from the pigment layer, remain adhered to the intermediate substrate and detach from the starting substrate.

[0022] If the intermediate substrate is provided with the relief structure, raised or depressed sections of the adhesive layer of the intermediate substrate are created analogously. In a first alternative, the intermediate substrate is provided with the relief structure and then coated with the adhesive layer. The relief structure is preferably embossed, in particular, embossed into an embossing lacquer layer of the intermediate substrate. In a second alternative, the intermediate substrate is pre-structured together with the adhesive layer, for example, by embossing. Again, either the pigment sections or the residual sections detach from the original substrate because they adhere to the adhesive layer of the intermediate substrate.

[0023] Instead of – or optionally in addition to – the relief structure, an adhesive structure can serve as pre-structuring. An adhesive structure is created on the pigment layer, the starting substrate, and / or the intermediate substrate, which defines the contour of the pigments. Such pre-structuring can be either an adhesion-promoting adhesive structure or an adhesion-preventing anti-adhesion structure. For example, the adhesive layer of the starting substrate could be pre-structured, in particular by selective removal or deactivation using a laser or by selective anti-adhesion printing. Depending on the pre-structuring, the pigments, i.e., the pigment sections of the pigment layer, preferentially adhere to the intermediate substrate and detach from the starting substrate.

[0024] The intermediate substrate comprises at least one intermediate substrate layer. Typically, the intermediate substrate comprises the intermediate substrate layer and an adhesive layer. The adhesive layer of the intermediate substrate is designed such that the pigment layer adheres more strongly to the adhesive layer of the intermediate substrate than to the starting substrate (or its adhesive or non-adhesive layer). The starting substrate comprises at least one starting substrate layer. Typically, the starting substrate comprises the starting substrate layer and an adhesive or non-adhesive layer. The adhesive layer of the starting substrate can be formed by a lacquer. The starting substrate layer preferably comprises a film—in particular a plastic film, such as PET film—and a cured embossing lacquer layer. The starting substrate layer and / or the intermediate substrate layer is preferably present as a (film) web with a minimum width of 20 cm, in particular 50 cm, and particularly preferably 100 cm.The film strip can be 200 cm wide. The strip has a minimum length of 10 meters, preferably 100 meters. It can be supplied on a roll.

[0025] The pigment layer can comprise several sublayers, which in turn can optionally be formed from sublayers. The pigment layer preferably comprises a first layer of increased stability (carrier layer) and at least one second, optically active layer. The first layer can, in particular, be formed by a cured lacquer.

[0026] The pigment can contain an additional motif, which is preferably arranged in precise registration with the contour of the pigment and / or has a contour independent of the pigment contour. The precise registration can be achieved in particular without additional effort if the additional motif is at least partially created in the step of creating the relief structure. For example, both the relief and an optically effective relief structure of the additional motif can be introduced by embossing the starting substrate. A contour of the additional motif can follow the (outer or inner) contour of the pigment at a fixed distance. The pigment sections of the pigment layer and thus the surface of the pigment can be completely flat, i.e., relief-free. Alternatively, they can have a surface structure - at least in some areas. The additional motif can be formed by the surface structure.The surface structure has a lower depth modulation, for example, from 3 nm to approximately 500 nm, than the contour-determining portion of the relief structure. The additional motif can have subwavelength structures, such as moth-eye structures, and / or diffractive structures, such as holographic gratings, the latter typically having periods between 500 nm and 1.5 µm. In particular, the additional motif can contain micromirrors. Their shape can be determined by the embossing and coated with a reflective layer (metal or HRI layer). Alternatively, the contour of the additional motif is independent of the contour of the pigment and can therefore be freely selected. For example, a continuous partial layer of the pigment layer can be created that refracts along the pigment contour, and an additional, discontinuous partial layer of the pigment layer can be created, which, for example, represents the additional motif.

[0027] The pigments resulting from the pigment layer can be described as flat pigments or platelet-shaped pigments. The outer contour can have almost any shape, provided the pigment is sufficiently stable for further processing. The inner contour, i.e., openings, can also be selected in any size and geometry.

[0028] Of course, the pigments are intended for printing. The pigments—particularly detached from the starting and / or intermediate substrate—are processed into a printing ink. A printing ink containing the pigments is printed. Printing is preferably carried out by screen printing, in particular by zonal doctor blade coating. Alternatively, the pigment can be printed by gravure printing and optionally by flexographic printing. The printing ink comprises the pigments and at least one solvent and optionally a binder. In particular, if the pigments produced have a pigment size of less than 15 µm, preferably less than 10 µm, the printing ink can be used in an offset printing process.

[0029] Compared to other manufacturing processes, pigments with increased complexity can be achieved in this case, even with smaller sizes and thicknesses, in particular with consistently high reliability. The pigment has a size or lateral dimension of less than 100 µm, in particular less than 50 µm, particularly preferably less than 30 µm. Currently achievable pigment sizes start at a few hundred nm. Pigments with sizes between 100 nm and 100 µm are possible, preferably between 200 nm and 50 µm, particularly preferably between 200 nm (or 2 µm) and 30 µm. The thickness of the pigments is in the range from 30 nm to 4 µm (or up to 2 µm), preferably between 100 nm and 1 µm.

[0030] The outer contour of the pigment exhibits deviations from a regular outer contour. All basic shapes from a simple polygon (with 3 to n corners), including a circle, are considered regular outer contours. Bulges or indentations that deviate from the regular basic shape have the following typical sizes: 100 nm to 30 µm, preferably 300 nm to 10 µm, and particularly preferably 500 nm to 5 µm. Deviations from a regular outer contour form weak points in the pigment. Thus, without the application of the present method, the pigment will break more quickly at its weak point within the pigment than at its outer contour. Relative to the pigment size, the maximum size of the pigment in one direction, the at least one indentation reduces the pigment at a weak point to 5% to 66%, or 5% to 49% of the pigment size.At its narrowest point, the pigment is therefore only 5% to 66%, preferably 5% to 49%, particularly preferably between 5 and 24%, of the pigment size. Analogously, bulges form correspondingly narrow spots (weak spots) in the pigment relative to the pigment size. Bulges (and / or indentations) form a narrow spot in the pigment, which is located at a distance of more than 3%, preferably more than 6%, particularly preferably more than 12%, of the pigment size from the outer contour. Accordingly, the minimum length of the bulge (measured from the pigment center or center of gravity to the outer contour) is 3% (6% or 12%) of the pigment size. At the narrow point, the bulge is only 1% to 33%, preferably 1% to 15%, particularly preferably 1% to 5% of the pigment size wide. The bulge has an opening angle at the narrow point, formed by the edges of the bulge, of less than 60 degrees, preferably less than 45 degrees, particularly preferably less than 30 degrees.The opening angle at the narrow point can be zero, for example in the case of a rectangular bulge (with parallel edges), or negative, for example in the case of a bulge that widens outwards.

[0031] A predefined inner contour (opening in the pigment) of the pigment can represent the predefined contour or complement the predefined outer contour of the pigment. The opening can be designed as a regular polygon (triangle, square, ... n-gon), circle, oval, irregular polygon (such as a trapezoid), symbol (with corners and curves), or text. Preferably, the opening follows the outer contour (partially or completely) and / or the opening follows additional information on the pigment.

[0032] The inner contour has a size of at least 100 nm. The pigment has a minimum width of 300 nm, in particular 500 nm or 1 µm, between the inner contour and outer contour, in particular a width of 300 nm to 10 µm, particularly preferably 500 nm to 5 µm. Relative to the pigment size, the pigment has a width of less than 66%, preferably less than 30%, particularly preferably less than 10%, of the pigment size at its narrowest point between the outer contour and inner contour.

[0033] Typically, pigments with identical contours are produced. In an advantageous embodiment, pigments with two (or three, or more than three) different predefined contours are produced simultaneously from one pigment layer. In further developments, the simultaneously produced pigments comprise (at least) one uniform, predefined outer contour and at least two different inner contours for the uniform, predefined outer contour, or (at least) one uniform, predefined inner contour and several different outer contours for the uniform, predefined inner contour. For example, the uniform outer contour can represent a first (supra-)national symbol, and the inner contour can represent regional (or correspondingly national) symbols.

[0034] A metal layer, for example made of aluminum, chromium, copper, iron, nickel, cobalt, silver, gold, or alloys of the aforementioned metals, can be used as an optical effect layer of the pigment. The thickness of the metal layer is between 2 nm and 200 nm, preferably between 10 nm and 50 nm, particularly preferably between 15 nm and 30 nm. The optical effect layer can be formed as a reflective or semitransparent layer; instead of a metal layer, a high-index layer (HRI layer) can be provided. The pigment preferably comprises a three-layer structure, which can be designed as a color-shifting and / or color-filtering structure. The pigment can be formed by the three-layer structure or comprise the three-layer structure as a supporting partial layer or as an optically active partial layer.The three-layer structures preferably consist of a semitransparent metal layer, a dielectric, and a reflective (or semitransparent) metal layer. Dielectrics such as SiO2, ZnS, MgF2, or TiO2 are used.

[0035] Particularly preferably, at least the optically active partial layers of the pigment are provided symmetrically to the pigment plane. Thus, the orientation of the pigment after the printing process is irrelevant. For example, the pigment can be formed by two identical semitransparent partial layers with a supporting spacer layer. Such pigments preferably exhibit a metallic luster with a specific color spectrum when viewed from above, while displaying a spectrum complementary to this color spectrum when viewed through, particularly preferably gold when viewed from above and blue when viewed through. In another variant, a dielectric and a semitransparent layer are provided symmetrically around a shared reflective layer (above and below).

[0036] To allow the pigments' orientation to be influenced by a magnetic field, a magnetic layer can be used, which can be formed, for example, from the metals iron, nickel, cobalt, or alloys containing these metals. Such alloys preferably contain additional elements such as Si, Nd, B, Gd, Sm, Sr, Ba, or Mn. The magnetic layer is advantageously located inside the pigments. In a particularly advantageous variant, the magnetic sublayer is provided between two reflective sublayers, for example, made of aluminum.The pigments particularly preferably have a central magnetic layer which is provided on both sides (symmetrically) with a three-layer structure, i.e. in particular on both sides - from the inside to the outside - comprises a reflective layer (preferably a reflective metallic layer), a spacer layer (preferably a dielectric layer) and an absorber layer (preferably a semi-transparent metallic layer).

[0037] This process makes it possible for the first time to create pigments with a fracture edge delimiting the pigment, which represents a fracture force that is greater than a corresponding fracture force for the pigment, and / or an internal fracture edge delimiting an opening in the pigment.

[0038] The breaking strength of the pigment is determined by its narrowest point. The pigment can therefore more easily have at least one acute angle in its outer contour with an angle of less than 45 degrees, preferably less than 30 degrees, or have an outer contour that tapers towards the pigment center. Such outer contours have previously been problematic and only conceivable with greatly increased effort, such as predetermined breaking points that are very thin compared to the thickness of the pigment layer. The breaking strength of the pigment is in this case at least a factor of 1.1, preferably 1.5, and particularly preferably a factor of 2 smaller than the breaking strength of the breaking edge. The breaking strength of the breaking edge can be determined (calculated) based on a breaking strength of the pigment layer (measured value) using the breaking edge (surface) and the contour. A breaking force is determined or measured as the maximum applicable force until the measuring object breaks.In this case, the pigment is preferably loaded at two points, each located at a predetermined distance from a support point or support line of the pigment. The ratio of the fracture forces corresponds at least approximately to the ratio of the fracture surfaces. The pigment cross-sectional area at the narrowest point of the pigment, i.e., in particular, the width of the weak point of the pigment times the height of the pigment layer, can be smaller than the surface area of ​​the fracture edge of the pigment at its outer contour, i.e., in particular, the length of the fracture edge times the height of the fracture edge.

[0039] The inner break line forms the inner contour of the pigment. The break line bordering the pigment forms the outer contour of the pigment.

[0040] Further embodiments and advantages of the invention are explained below with reference to the figures, in which a true-to-scale and true-to-proportion reproduction has been omitted in order to increase clarity.

[0041] They show: Fig. 1a, 1b two different pigments with a given contour in plan view; Fig. 2a, b, c pigment layer, structured pigments and loose pigments, each in plan view; Fig. 3 a relief-structured starting substrate with pigment layer before contacting with an intermediate carrier substrate; Fig. 4 the starting substrate and the intermediate carrier substrate from Fig. 3 after separating the substrates; Fig. 5 an adhesion-structured starting substrate with pigment layer before contacting with an intermediate carrier substrate; Fig. 6 the starting substrate and the intermediate carrier substrate from Fig. 5after separation of the substrates; Fig. 7a, 7b shows a multilayer pigment of a given contour in plan view and in cross-section; and Fig. 8 shows a manufacturing device for pigments.

[0042] The Fig.1a and 1b The pigments 1 shown have different outer contours 5. The pigment 1 in Fig. 1b additionally includes an inner contour 6 that defines an opening in the pigment 1. Due to the pigment size, which is in the range of 100 nm to 100 µm, the contour 5, 6 cannot be recognized by the observer without aids. In this respect, the pigment can be used as a hidden security feature.

[0043] Both pigments include an additional motif 8, which is precisely aligned to a contour of the pigment. The contour of the additional motif 8 in Fig1a follows the outer contour 5 of the pigment at a given distance. In Fig. 1bthe (here round) contour of the additional motif follows the (round) inner contour 6 of the pigment 1. However, the additional motif can also have its own contour independent of the pigment contour.

[0044] Fig. 2a shows a top view of a starting substrate with pigment layer 21. A continuous pigment layer 210 has been created on a pre-structured starting substrate. According to the pre-structuring, the pigment layer 210 comprises a plurality of pigment sections 211 and the remaining sections 212 located between the pigment sections.

[0045] In the Fig. 3In the embodiment shown in cross-section, the starting substrate 20 is provided with a relief as a pre-structuring. The relief structure is formed by recessed sections 217. The starting substrate 20 comprises at least one starting substrate layer 215, in particular in the form of a PET film, and an optional embossing lacquer layer 216. In a variant not shown but preferred, the relief structure is implemented only in the embossing lacquer layer 216. The pigment layer 210 created on the starting substrate is a continuous layer. In less advantageous embodiments, the pigment layer is already structured, for example, by correspondingly wide and / or deep depressions. Pigment sections 211 and residual sections 212 of the pigment layer are formed according to the relief structure. The pigment sections 211 lie on the raised sections of the relief structure, and the residual sections 212 in the depressions 217. As in Figure 2aAs can be seen, the pigment sections 211 are already pre-structured according to the contour of the pigments 1. The remaining sections 212 lying between the pigment sections 211 have a contour inverse to that of the pigments.

[0046] Likewise in Fig. 3 Shown is an intermediate substrate 30, which comprises an intermediate substrate layer 315, for example, another PET film, and an unstructured adhesive layer 316. The intermediate substrate layer 30 is brought into contact with the pigment layer 210, as indicated by the arrow. During this step, pressure can be applied and the temperature increased. Due to the relief structure, the pigment portions 211 of the pigment layer 210 adhere to the adhesive layer 316 of the intermediate substrate. The remaining portions 212 do not come into contact with the adhesive layer 316 at all, or at least not sufficiently to adhere to it.

[0047] The starting substrate and the intermediate substrate are separated again as shown in Fig. 4 - again indicated by an arrow. Fig. 4 shows the starting substrate including residues of the pigment layer 23 and the intermediate substrate including pigment sections 33 already in the separated state.

[0048] When the two substrates are separated, the pigment layer breaks. It is structured into the individual pigments, which are present as pigment sections 331. The pigment sections 331 adhere to the adhesive layer 316 of the intermediate substrate. Between the pigment sections 331, there are - as in Fig. 2b visible in plan view - free intermediate substrate surfaces 338. The remaining sections 232 of the pigment layer are still present on the starting substrate 215, 216 after separation.

[0049] As in Fig. 2cAs indicated, the pigment sections 331 are subsequently separated from the intermediate substrate and are then present as a plurality of pigments 1. The pigments 1 are further processed into a printing ink.

[0050] At the time the pigment layer is structured into pigment sections, the intermediate substrate protects the pigment sections from breakage by breaking and detaching them from the original substrate. The pigment sections are not subjected to unnecessary force and can thus be designed significantly thinner or more delicately than conventionally.

[0051] Fig. 8 shows a device for producing pigments 1 starting from a starting substrate with a pigment layer.

[0052] The starting substrate with pigment layer 21 is unwound from a first starting substrate layer roll 88. An intermediate substrate 31 is unwound from an intermediate substrate roll 87. The unwound intermediate substrate 31 is preferably provided with an adhesive layer, for example, printed or sprayed. The substrates are brought into contact with one another, for example with the aid of a contact roller 82. The pigment layer of the starting substrate 22 adheres to the adhesive layer of the intermediate substrate 32. The substrates are separated from one another again, for example, at a separating roller 83. The intermediate carrier web with pigment sections 33 is guided to a release unit 84. In the release unit 84, the pigments 1 are released from the intermediate carrier web 315, for example by dissolving the adhesive layer 316 of the intermediate carrier web.

[0053] The plurality of pigments 1 can now be further processed into printing ink. The starting substrate with pigment layer residues 23 can be freed of the pigment layer residues in an optional, additional stripping unit 86 and rewound onto a second starting substrate roll 89. The stripping unit 86 can dissolve the pigment layer residues 23 on the starting substrate (e.g., chemically decompose them and / or mechanically remove them). The starting substrate and / or the intermediate substrate can be reused for the production of further pigments.

[0054] The device shown (with a separating roller) enables continuous structuring, in particular a continuous breaking of the pigments from the pigment layer. Other variants are conceivable, for example, with a stamp, which allows the (contacting and) separation of the substrates - more like in Figure 3shown - for independent substrates one after the other or for sections of a substrate web one after the other.

[0055] The present procedure can be divided into several sub-steps.

[0056] Step 1 (optional): Coating a starting substrate layer or a carrier material, e.g. a PET film, with an embossing varnish.

[0057] The embossing lacquer layer is preferably a lacquer with low adhesion to the pigment layer. The embossing lacquer can, in particular, be selected so that a (PVD) layer can be vapor-deposited onto it in a separable (or mechanically removable) manner. The embossing lacquer can be a UV-curable lacquer or a thermoplastic embossing lacquer.

[0058] Step 2: Pre-structuring of the initial substrate layer, in particular with a relief structure.

[0059] The relief structure is introduced into the embossing varnish by (roll-to-roll) embossing binary structures that correspond to the outline of the effect pigments. Depending on the embossing varnish used, the embossing is carried out under the influence of UV radiation or heat to create and fix the structures in the varnish. The depth of the embossed structure depends on the thickness of the effect pigments: for thin pigments (e.g., 300 nm), a depth of approximately 1 µm or more is sufficient. Thicker pigments require deeper embossed structures. The flanks of the binary embossed structure are sufficiently steep so that the pigment layers can be broken up there later.

[0060] If the pigments are later required to display not only their contours but also additional information, these can be embossed as surface modulations on the raised and / or depressed areas of the binary embossing. This is preferably done during the same embossing step, i.e., the embossing tool contains the deep binary structure for defining the pigment outlines and, at the same time, the flatter surface structure for achieving additional effects, such as optical effects, in the pigments. This procedure has the significant advantage that the surface modulations that create the optical effects are perfectly registered with the contour of the effect pigments. For example, diffractive lettering can be placed precisely in the center of pigments.

[0061] As an alternative to embossed varnish, a structured release varnish of a suitable thickness, such as a printed one, can also be used. A disadvantage of this option, however, is that lower resolutions can be achieved with a printing process than with an embossing process.

[0062] Step 3 (optional): If no lacquer was used in step 1, to which the subsequently deposited PVD layer adheres only weakly, a third step is required to prevent strong adhesion between the embossing lacquer and the coating deposited in the next step. For example, an anti-adhesion layer can be applied.

[0063] Step 4: Creating the pigment layer on the embossed structure, including all sublayers of the pigment layer.

[0064] The pigment layers are typically vapor-deposited, e.g., by PVD coating the embossed structure. This involves applying the previously described sublayers or sublayers of the sublayers. It is important that the layers remain detachable from the embossed structure. Suitable processes include PVD processes, of which thermal vapor deposition is particularly preferred, as the directed particle flow results in less coating on the vertical walls between the raised and depressed areas of the binary embossing. This facilitates subsequent separation of the coating when separating the substrates.

[0065] Alternatively, a partial layer, particularly a metallic layer, could also be applied using gravure or flexographic printing processes. Due to the required predetermined breaking point, solvent-based or water-based inks with metal flakes are preferred for this purpose, which preferably have a thickness of less than 200 nm, particularly preferably less than 150 nm.

[0066] Step 5: Providing a film coated with a sticky and, if necessary, deformable varnish as an intermediate substrate.

[0067] Step 6: Bringing the pigment layer into contact with the intermediate substrate. The intermediate substrate is laminated to the embossed and coated first film, the starting substrate, under pressure and, if necessary, at elevated temperature. The coating components located on the raised areas of the binary embossed structure bond firmly with the tacky varnish. Any surface modulation, such as a holographic grating, will be imprinted into the tacky varnish. The pigment layer in the recesses of the embossed structure preferably does not touch the adhesive layer.

[0068] Step 7: When the two films are separated or separated by winding, the sections of the coating that are releasably bonded to the raised areas of the binary embossing are transferred to the adhesive lacquer of the second film – the intermediate substrate. However, those sections of the coating that are located in the recesses of the binary embossing remain on the first film – the original substrate.

[0069] Step 8: Finally, the pigments, whose outlines are well defined, are removed from the respective carrier film, for example, by partially or completely dissolving the lacquer supporting them in a suitable solvent. The pigments in solution are then further processed in appropriate steps. Care must be taken to ensure that they do not clump together.

[0070] The sections of the pigment layer that have been transferred and detached onto the intermediate substrate, the second film, are processed as pigments.

[0071] The original substrate, the first film, with the remaining pigment layer sections could be disposed of. Alternatively, the coating components remaining on the first film could be further processed into pigments (without a predefined contour or with a negative contour). It is therefore also possible to process both the pigment layer sections on the first and second films into different pigments.

[0072] However, the starting substrate can also be reused for this process, optionally after the remaining sections have been removed from the starting substrate. A pigment layer can be created (structured, etc.) several times in succession on the starting substrate with the relief structure, the first foil. This saves material costs and process steps, as the embossing varnish and embossing do not have to be repeated repeatedly. A UV-curable material is preferably used as the embossing varnish, in which the structures are permanently embossed. In particular, this ensures that the elevated temperature during the lamination step does not impair the relief structure.

[0073] In the embodiments described so far, the starting substrate was provided with a relief structure in which the pigment sections with the predetermined contour are formed on the elevations. Alternatively, the relief can also be designed inversely. It can comprise flat depressions with the predetermined contour for the pigment sections and elevations for the remaining sections. The remaining sections then detach from the starting substrate upon separation and adhere to the intermediate substrate. The pigment sections (in the depressions) remain on the starting substrate and are only detached from the starting substrate after the substrates have been separated. Finally, in a less advantageous embodiment, it is even conceivable to provide the intermediate substrate layer with the relief structure so that the (non-prestructured) pigment layer adheres to the adhesive layer of the intermediate substrate in the area of ​​the elevations of the relief.The elevations can alternatively correspond either to the pigment sections with the given contour or to the remaining sections.

[0074] The Fig. 4The pigment sections 331 arranged on the intermediate substrate 33 (or alternatively the pigment sections arranged on elevations of the intermediate substrate) can optionally be provided with a further partial layer. The further partial layer can be provided over the entire surface and advantageously applied only to the pigment sections 331 using a contact printing process (kiss print). The partial layer is not transferred to the free sections 338 of the adhesive layer, since only the pigment sections 331 come into contact with the partial layer. The contact printing process implicitly uses the existing height differences of the pigment sections on the substrate as a printing template. The pigment sections, including their further (rear-side) partial layer, are detached from the intermediate substrate.

[0075] In principle, partial layers of the pigment layer could also be created using a contact printing process. For example, an additional partial pigment layer can be printed onto existing pigment layers, such as vapor-deposited ones, that are present on the original substrate with a relief structure. The additional partial layer (provided over the entire surface) is then applied analogously only to the raised sections of the pigment layer.

[0076] In the design according to Figs. 3 and 4 The pigment layer is pre-structured with a relief structure to define the contour of the pigment. Figs. 5 and 6 show alternative designs in which an adhesion-determining layer is structured to specify the contour.

[0077] The starting substrate with pigment layer 21 comprises Fig. 5a substrate layer 516, 517, 518 and a pigment layer 510, which in turn contains two partial layers 513, 514. A structured adhesion-determining layer is provided on the PET film 515, which can be formed as a continuous anti-adhesion layer 516 with adhesive layer sections 517 or as an adhesive layer 518 arranged on the substrate layer 515 (or the anti-adhesion layer 516). The pigment layer 510 comprises the continuous pigment partial layer 513 and a non-continuous (but already structured) pigment partial layer 514. Pigment sections 511 of the pigment layer and remaining sections 512 are predetermined by the adhesion structure 517, 518.

[0078] The starting substrate 21 is prepared as in Fig. 5symbolically represented by the arrow, is brought into contact with the adhesive layer 316 on the intermediate substrate. The adhesive layer 316 can also come into contact with the remaining sections 512, i.e., not just the pigment sections. The adhesive layer 316 and the adhesive structure 517, 518 are coordinated in such a way that the pigment layer adheres more strongly to the adhesive structure 517, 518. The pigment layer, in turn, is structured into the pigment (sections) when the substrates are separated.

[0079] Fig. 6shows, after separation of the substrates, the starting substrate with pigment layer residues 23 and the intermediate substrate including pigment sections 33. Residual sections 532 of the pigment layer remain adhered to the adhesive structure 517, 518. The pigment sections 531 remain adhered to the intermediate substrate, thus having detached from the starting substrate or its non-adherent layer 516 during separation. Free sections 338 of the adhesive layer 316 remain between the pigment sections. The pigment sections 531 comprise the two partial layers 513, 514. The pigment sections 531 are (after separation) detached from the intermediate substrate layer 315, 316 and further processed as pigments, in particular into a printing ink.

[0080] If the solvent used to dissolve the pigment segments (e.g., water) is compatible with the binder of the printing ink, the dispersion can also be added directly to a printing ink. If necessary, excess solvent can be removed using a vacuum mixer. In another variant, the pigments 1 are dried using a freeze dryer (solvent removed), and the dry pigments are mixed into a printing ink.

[0081] In Fig. 7a and 7b A pigment 1 is shown in cross-section and top view. The pigment comprises - as in Figs. 5 and 6The pigment shown in the drawing comprises two pigment sublayers 701 and 702. Both pigment sublayers can in turn be formed by sublayers, such as a three-layer structure with absorber, dielectric, and absorber (or reflector). The second pigment layer 702 has a break edge 705, which corresponds to the outer contour of the pigment 1. The first pigment sublayer 701 is provided as additional information 708 with a contour on the pigment 1 that is independent of the outer contour. Only in Fig. 7b It is indicated that the pigment 1 can also have - for example two - openings 706.

[0082] In the following, variants of liability-determining pre-structuring are discussed, which are analogous to the two Figures 5 and 6The structured adhesion-determining layer can be designed as an adhesion layer or as an anti-adhesion layer. It can be applied over the entire surface and removed in sections by laser irradiation, in particular either according to the pigment sections or the residual sections. Alternatively, the adhesion-determining layer is applied in sections by printing, i.e., only in the corresponding (pigment or residual) sections. The adhesion-determining layer can be formed by a varnish, which, as an embossing varnish, preferably comprises an "optical" embossing that generates additional information in the pigment.

[0083] In a further optional variant, a structured print is applied in pigment form, i.e., in the subsequent pigment sections, to a (untreated) poorly adhering layer 516. In a second process step, the structured-printed substrate layer is pretreated using a pretreatment system (plasma, open-air plasma, flame pretreatment, or corona pretreatment system). The non-adherent layer 516 is converted into an adhesive layer through the pretreatment. The pre-printed sections in pigment form serve as a stencil for the pretreatment. Accordingly, adhesive sections 517 are created, to which the remaining sections 512 of the pigment layer remain adhered during separation, while the pigment sections 511 detach from the still poorly adhering layer 516 during separation.

[0084] The adhesion-determining layer preferably has a thickness of at least 1 µm. This creates predetermined breaking points in the pigment layer created on top, which, for example, has a thickness of 30 nm to 4 µm, analogous to the relief structure. It would also be possible to apply an etching or wash ink using a printing process to structure the adhesion-determining layer. Structuring the pigment layer directly using the wash or etch ink would be more of a theoretical possibility. However, the present process reveals its most significant advantages on pigment layers that have not yet been structured.

[0085] Another method for producing pigments with a narrow size distribution could be achieved using crack templates. A crack template refers to a layer on a carrier film (e.g., PET) that exhibits a network of continuous cracks, so that the entire layer ultimately consists of individual islands. This crack template is metallized, with the metallization tearing away at the island edges due to the height difference, and the island size thus determines the pigment size. Ideally, the pigment layer is structured by the crack formation. The more relevant case here is one in which the crack formation does not lead to a complete separation of the pigment layers.

[0086] In order to preserve the pigments, the crack template is either detachable from the film (the crack template detaches from the film but remains connected to the other pigment layers) or the crack template is itself water-soluble or soluble in another solvent, so that it dissolves - in this case after the separation of the substrates - and releases the pigment.

[0087] Two types of pigments can therefore be produced: Pigments consisting of a first pigment partial layer, such as a vapor-deposited metallization, and the crack-inducing layer; or pigments consisting only of the pigment layer, such as a vapor-deposited metal layer (without the crack-inducing layer).

[0088] The crack-forming layer can contribute to the stability of the pigments or the crack-forming material can have functional properties (e.g. fluorescent dyes or magnetic particles).

[0089] Various methods are known for producing the crack template. In a first embodiment, a dispersion with a sufficiently high minimum film formation temperature (MFT > 50°C) applied over the entire surface of a carrier film forms cracks upon physical drying. The dispersion consists of particles of organic polymer (e.g., based on polyacrylates, polystyrenes, etc.) or inorganic (e.g., SiO2, TiO2, Al2O3, etc.) nature, or mixtures thereof, dispersed in water. To ensure the solubility of the crack template in water, water-soluble compounds can be added. In another embodiment, a brittle UV varnish with high shrinkage is applied over the entire surface of a carrier film. During radiation curing, cracks form throughout due to the shrinkage. This crack template can be further metallized to retain the pigments. Ideally, the UV varnish is designed to self-detach in water (water-soluble UV varnishes).For water-insoluble UV coatings, a water-soluble intermediate layer is conceivable to dissolve the pigments from the base film in water. A counter-laminating film with an adhesive will dissolve the pigments from the carrier film, with the adhesive subsequently dissolving, thus releasing the pigments.

[0090] Controlling crack formation is crucial for the size distribution and shape of the pigments and depends on the chosen manufacturing method for the crack template. For physically drying dispersions, the island size (=pigment size) is adjusted using known parameters such as minimum film formation temperature, layer thickness, particle size, additives, or drying conditions. Furthermore, it is known that the first generation of cracks runs vertically inward from the edge of the printed image, whereupon the second generation of cracks forms parallel to the edge of the printed image and thus between the first generation of cracks. The resulting ladder-like crack template leads to rectangular islands or pigments. However, this effect decreases with increasing distance from the edge of the printed image. If only rectangular islands are desired, the film is printed in stripes. Hexagonal islands and thus pigments are also possible.

[0091] For crack templates based on UV varnishes, a predetermined breaking point can be introduced during radiation curing by suitable structures on an embossing tool (PWZ). The PWZ, for example, presses two notches into or through the UV varnish (cf. nanoimprinting), whereby after radiation curing, a crack is initiated at the shortest distance between the two notches due to shrinkage. By specifically arranging the notches, the cracks can be specifically controlled in lines and grids. Of course, this method can also be used to easily produce hexagonal pigments by generating cracks at 120° angles to each other using the notches, similar to a trident star. The variety of the arrangement of the notches relative to each other and the type of notches themselves allows for a variety of shapes for the islands and therefore for the pigments.

[0092] Pigment sections (or islands) created with the help of a crack template can also be Figure 3, 4 , 5, 6or 8 described method from the starting substrate and preferably structured at the same time.

Claims

1. Process for producing pigments (1) with a predefined contour (5, 6), comprising the following steps: - creating a pigment layer (210) on a starting substrate (20); - detaching it from the starting substrate (20); and - structuring the pigment layer (210) into a multiplicity of pigments (1); characterized by bringing the pigment layer (210) into contact with an intermediate substrate (31), with at least some portions of the pigment layer (210) adhering to the intermediate substrate (31); and separating the intermediate substrate (31) and the starting substrate (21).

2. Process according to Claim 1, characterized in that the pigments (1) are protected against breaking of the pigments (1) by the contact with the intermediate substrate (31) for the detaching step and / or structuring step.

3. Process according to Claim 1 or 2, characterized in that the predefined contour of the pigments (1) is a predefined outer contour (5, 705) and / or a predefined inner contour (6, 706).

4. Process according to one of Claims 1 to 3, characterized in that the pigment layer (210) is structured into the multiplicity of pigments (331, 531) by the step of separating the intermediate substrate and the starting substrate.

5. Process according to one of Claims 1 to 4, characterized in that the pigments (1) are detached from the starting substrate (21) by the separating step.

6. Process according to one of Claims 1 to 4, characterized in that the multiplicity of pigments (1) are present on the starting substrate after the separating and are then detached from the starting substrate.

7. Process according to one of Claims 1 to 3, characterized in that the pigment layer is structured before the separating step.

8. Process according to one of Claims 1 to 7, characterized in that a relief structure (217) predefining the contour (5, 6) of the pigments (1) is created in the starting substrate and / or the intermediate substrate.

9. Process according to Claim 8, characterized in that the relief structure is effected by embossing a curable - preferably by means of UV light - embossed layer of the starting substrate and / or of the intermediate substrate.

10. Process according to one of Claims 1 to 7, characterized in that an adhesion-determining structure predefining the contour (5, 6) of the pigments (1) is created on the pigment layer, the starting substrate and / or the intermediate substrate.

11. Process according to one of Claims 1 to 10, characterized in that the pigment (1) contains an additional pattern (708) which preferably is arranged in register in relation to the contour (705, 706) of the pigment and / or has a contour (708) independent of the pigment contour (705, 706).

12. Process according to Claim 11 with Claim 8 or 9, characterized in that, in the step of creating the relief structure, the additional pattern is at least partially conjointly created, in particular in the form of an optically variable embossed structure.

13. Process according to one of Claims 1 to 12, characterized in that the pigment layer comprises at least one continuous partial layer (702) and an additional, non-continuous partial layer (701).

14. Process according to one of Claims 1 to 13, characterized in that the pigment layer is created on a curable varnish layer of the starting substrate, the curable varnish layer being arranged in particular on a film layer of the starting substrate; and / or adheres to a varnish layer of the intermediate substrate, the varnish layer being arranged in particular on a film layer of the intermediate substrate.