RU2459710C2 - Protective device including binding substance with variable optical properties - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: structure providing variable optical effect comprises first substrate and second substrate attached to the former by binder for hot embossing including binder substance activated on feed power thereto and comprising multiple variable-colour particles distributed in said substance to cause optically-variable effect detected through first substrate.Note here that said particles vary their colour on varying light incidence angle. In forming the structure, a) first substrate is produced including binder activated on feeding power thereto and comprising multiple variable-colour particles distributed in said substance; b) first substrate is located nearby second substrate without adding binder between them so that binder activated on feeding power thereto is arranged between first and second substrates, and c) binder activated on feeding power thereto is cured by hot embossing.

EFFECT: multilayer protection against counterfeit with high-quality colour control.

22 cl, 5 tbl, 30 dwg

Description

FIELD OF THE INVENTION

The present invention relates, in general, to hot stamping and, in particular, to attaching an optical device to a substrate or article during hot stamping using a hot stamping binder material containing flakes that create an optical effect.

State of the art

Further, the term “chromogram” refers to optical structures containing a substrate with a pattern or with windows and coatings or layers providing special effects, these layers or coatings are supported by a substrate with a pattern or with windows or support the specified substrate. Chromograms of various kinds are described in US Patent Application Publication Number 20060285184 and are used as security devices or to improve product safety and aesthetic appeal.

One type of chromogram is an optical structure that provides surface relief effects, such as holograms or diffraction gratings, and which contains patterns such as alphanumeric characters, barcodes or graphic or visual drawings, and in which there are additional optical effects in areas around a similar pattern. Similar structures are described in US Patent Application No. 20060077496, filed by Argoitia and others, published April 13, 2006. Hereinafter, the referenced application will be referred to as the '496 application. Another chromogram type structure is described in US Patent Application No. 20050128543, filed by Phillips and others. Substrates with patterns from the '496 application, which contain areas with windows through which to look, are coated with varying optical properties (IOS) or ink with varying optical properties that are visible through windows. All references mentioned hereinafter are incorporated herein by reference.

When using the term “patterned” layer, the following is meant: a reflective, opaque or partially transmissive layer is thus applied to a substrate, which can be flat or have a relief surface such that the layer forms the desired “pattern” or image. Without limiting the invention, the reflective layer with a pattern may be in the form of letters, numbers, barcodes and / or graphic or visual drawings.

One type of embossed surface pattern is a demetallized hologram described in US Pat. Nos. 5,314,767, 6,616,190 and 7,081,819. To improve the protection of holograms and prevent the manufacture of contact copies, a technology for manufacturing holograms using the demetallization process has been proposed. Demetallized holograms and “stickers” are used in the manufacture of passports and ID cards in order to protect photographs and data.

The present invention mainly relates to types of chromatograms made using a binder material containing flakes and / or a coloring agent used during hot stamping and providing optical and / or magnetic effects. So far, the desired quality of the binder materials used to bond two substrates together, where one substrate is visible through the other, is that the binder material is substantially transparent and have the required binding properties. Thus, the goal was to have a binder material that “looks” as invisible as possible and essentially has a refractive index corresponding to the refractive indices of the substrates that it binds, so the binder layer does not substantially negative impact on transmitted light.

For mounting images on various substrates, such as paper, plastic film and even hard substrates, a foil for transfer during hot stamping is proposed along with a hot stamping machine. Hot stamping is a dry process. One commercially available hot stamping machine for substrates is the Malahide E4-PK machine from Malahide Design and Manufacturing Inc. Machines of this type are shown and described on the Internet at www.hotstamping.com. Simplistically, in the hot stamping process, to attach the foil to the product or substrate, the stamp is attached to a hot plate, which is pressed against the cylinder acting on the hot stamping foil. The transfer process by rolling by a cylinder can also be used in the present invention. In this case, the substrate of the product and the binder material (activated by applying heat or ultraviolet light) are brought together and clamped to transfer the hot stamping layer to the substrate of the product.

The image is usually formed using a metal stamp or a stamp from silicone rubber, in which the desired image is cut. This stamp is located in the hot stamping machine and is used to extrude the image on the hot stamping foil, which is achieved through the use of a combination of heating and pressure. The back side of the foil is usually coated with a dry, heat-activated and thermoset binder, such as an acrylate-based binder. When heat is applied, the binder material becomes sticky in areas of the heated image and adheres to a paper or plastic substrate.

Hot stamping is described or referred to in US Pat. Further details of the hot stamping process can be found on pages 440-445 of the Encyclopedia of Modern Plastics, 1979-1980.

The above-mentioned US Pat. No. 5,059,245 describes the formation of an optical coating on a substrate, in which the optical substrate in one embodiment of the invention comprises flakes with varying optical properties deposited in the carrier in the form of paint or ink, which is then dried or cured on the substrate.

Flakes with optical characteristics placed in a bonding material may have one or more predetermined optical characteristics, for example, flakes may have a color that varies depending on the angle of incidence of the light, or flakes may be diffractive, or may contain hidden characters located in them or on them, or scales, can simply be reflective or absorbing light. In some examples, flakes that create optical effects are characterized by a combination of optical effects, for example, depending on the desired effect, they may combine diffraction and color change, or they may be diffractive and reflective, or they may combine diffraction and strong absorption property. Moreover, flakes that create various optical effects can be mixed in the right proportions. Pigments that can be added include those that create interference, for example, mica-based pigments, Fabry-Perot-type pigments, liquid crystal pigments, including pigments that change color when viewing angles change, and do not change color pigments, such as gold and nickel, and other metal flakes. Paints and / or other pigments can be added to the binder to change the color of interference and / or diffraction pigments, including hidden plates, known as chemical markers and other particles of a certain shape. Examples of hidden flakes include, for example, the markers described in the US patent application, publication number 2006/0035080, which is incorporated herein by reference, the specific form of particles described in the US patent application, publication number 20060035080, magnetic flakes, fluorescent pigments commonly activated with ultraviolet to form visible light; or specialized anti-UV materials activated with ultraviolet to form visible light.

Until now, when a layer of material, such as an ink-coated substrate containing flakes with varying optical properties, has been attached to another substrate or product during hot stamping, a layer of binder is usually hot stamped, typically 2-20 microns thick and which activated when heat is applied, applied to a substrate or article to adhere a layer of material to the substrate or article by applying the required amount of heat and pressure.

As shown in FIGS. 1a and 1b, US Pat. No. 7,029,745 describes a method for attaching a protective article, such as a protective article 30, to a carrier substrate 66 using a hot stamping process. FIG. 1 a shows a protective article 30 comprising a release layer 62 formed on one side of a light-transmitting substrate 24, such as an acrylic coating with an interference pattern formed thereon. The separation layer 62 allows you to separate the protective product 30, containing the substrate 24, the absorbing layer 18, the dielectric layer 20 with the optical interference pattern 15, and the reflective layer 22, from the carrier substrate 64 during the hot stamping process.

As shown in FIG. 1b, the release layer 62 and the carrier substrate 64 are separated when the protective article 30 is attached during hot stamping to an article such as the carrier layer 66, while the protective article 30 is attached to the carrier substrate 66 using a binder material layer 68 . Sometimes the separation layer remains with the substrate 66. The bonding layer 68 of the binder material and the carrier substrate 66 join when a heated metal stamp (not shown) comes into contact with the supporting structure 64. At the same time, the heated metal stamp presses the bonding layer 68 against the carrier substrate 66 and heats it in order to more effectively adhere to the carrier substrate 66. Moreover, the heated metal stamp softens the separation layer 62, thereby contributing to the separation of the protective article 30 from the carrier structure 64, which nd then discarded. When the protective article 30 is attached to the carrier substrate 66, an image made on the protective article 30 is seen when viewed from the substrate 24 in the direction of the optical coating 16.

In the field of hot stamping, there are a large number of commercially available binder materials designed to provide the required adhesion of the foil to the same material or another material when exposed to heat and pressure. Although these heat-activated binders fulfill their function, they do not provide additional functions that are currently considered very useful.

For example, the authors of the present invention have found that these dry binder materials activated by heating can be applied to substrates and special flakes that create an optical effect, such as magnetic flakes, magnetic field oriented flakes, magnetic flakes, can be placed or mixed in advance flakes with color-changing properties, color-changing flakes, color-switching flakes, diffractive flakes and / or hidden flakes bearing a feature, also known as a marker.

An object of the present invention is to provide a hot stamping binder that contains flakes that create special effects, said flakes being visible through one or more layers of binder. It was not expected that the addition of pigment with varying optical properties to the hot stamping binder would result in an acceptable level of adhesion. The binder material can also be printed in the form of a pattern so as to allow transfer of the pattern even when a flat die is used to carry out the transfer during hot stamping. Printing binder material, compared with the situation when the image is on the stamp of the device for hot stamping, allows you to get the best transferred images with higher sharpness, without the "edging", often present when transferring using foil. Edging refers to the rough edges of the image obtained using foil during hot stamping, for example, on the surface of the paper. The problem is often obvious when transferring the letter “A” using hot stamping, when the triangle of the letter “A” is covered with foil.

The purpose of the invention is to offer a chromogram in which a separate layer is eliminated, providing special effects. This is done by adding flakes that create special effects to the hot stamping binder, designed to bond two objects together. This simplifies the manufacture of the product and reduces the manufacturing cost.

The purpose of the present invention is to connect the substrate to another substrate or object during hot stamping, and only bonding material is used to connect, providing optical effects and containing flakes that create optical effects.

Security threads are currently known. US patent No. 4186943, issued by Lee (Lee), describes a security thread with windows contained in paper banknotes. Lee used symmetric structure diachronic coatings in a fully dielectric optical array so that the same reflected and missed color and the effect of color change were visible on both sides through elongated windows of the paper substrate. In one embodiment of the invention, the paper is removed at various places above the integrated security thread so that the thread is better visible. Moreover, unfortunately, counterfeiters have commercially available transparent films made of hundreds of alternating layers of polymer films that produce a color change and reflection and transmission characteristics similar to those described in the '943 document. This is written at http://www.ptonline.com/articles/200603fa1.html. This makes the foil on a fully dielectric basis vulnerable to counterfeiting.

In the patent application, publication number US 20060255586, the author Lazzerini (Lazzerini), describes a protective device that contains holographic areas with a continuous metal layer of aluminum, the thickness of which undergoes changes. WO 2004014665, by Lazzerini, describes a method for “thinning” an applied layer of aluminum by chemical etching after some regions of aluminum are protected by transparent inks adapted to protect aluminum from exposure to acid-based substances. Aluminum becomes thinner, while the optical density decreases from 1.8 to 0.7, and the transmission varies from 1.6% to about 20% in area “A”, paragraph 3 of the '586 patent application. In other words, aluminum is opaque in areas other than part “A” and only translucent in areas “A”. The use of magnetic elements combined with holographic elements is mentioned, but the nature of the magnetic elements is not indicated. Another version of the invention uses color-changing inks located between the protective layer of polyethylene terephthalate (PET) and a continuous aluminum metal layer. The type of color-changing ink is not defined - they can be transparent mica-based pigments that change color when the viewing angle changes, or liquid crystal color-changing inks - in both cases they are transparent (in our invention, the pigment is opaque). In any case, Lazzerini does not describe a color-changing material based on a binder with variable optical properties (SMIOS), in the said application there is no color change on both sides of the security thread, there are no hidden markers and there are no demetallized parts in the holographic regions and there are no magnetic elements, enclosed in a color-changing pigment.

US Pat. No. 7,054,042, issued to Holmes and others, hereinafter referred to as the '042 patent, describes a device using a demetallized hologram with a thin film that changes color and which is located below. The use of a thin-film interference light filter has a major drawback from the point of view of color control, since for the methods used, in particular vacuum deposition methods, at operating speeds (at which they are competitive), the error in the thickness of the dielectric layer at best is plus or minus 2%. As described in the '042 patent for the Fabry-Perot structure, the usual solution is the following: an opaque aluminum / low refractive index layer, i.e. MgF ₂ / Cr absorption layer, 3 microns thick. With a spread of 2% at 4 QW optical thickness of 550 nanometers, this spread in thickness leads to a ΔE color value of 27 units and at 6 QW optical thickness of 550 nanometers, a ΔE color value of 31 units is obtained. From a practical point of view, this variation in color leads to a situation where it is difficult to distinguish a genuine product from a fake. One hope for improving the color of the foil in the vacuum process is a large editing, which leads to a rise in price of the product.

US Pat. No. 5,700,550 to Uyama describes the use of a fully dielectric optical array on a holographic layer in which color management is even worse than in '042, because the structure described by Uyama contains five layers of alternating ZnS and MgF ₂ or TiO ₂ and SiO ₂ . Each layer has a spread of 2%, which leads to an even greater color change. Also, in the said patent, the device is required to be located on a black background, since otherwise (when placed on a white substrate) the nature of the light transmission for the specified device leads to the fact that a beam of light reflected from the substrate and transmitted back through the device, and a beam of light reflected from the interference optical set. Even if the backing (that is, banknote paper) was colored, then re-combining the light leads to low color saturation.

The purpose of the present invention is to eliminate the disadvantages existing in the prior art, so that a new security device having the required characteristics of a thread for banknotes or other paper documents or even plastic documents has a multi-layer anti-counterfeit system, which could be made with high quality color management, it would also contain visible and hidden signs, as well as protection that ensures the strength of the device on both sides while maintaining a minimum thickness. Thus, it is necessary to propose a new security thread with improved properties, which is easier to install. This problem is solved as follows: the observer is given protective signs that can be remembered and which determine a distinguishable color change, and hidden signs that the machine analyzes or which are analyzed in court.

The purpose of the invention is to provide a simplified multilayer protective device using a binder material with variable optical properties (MOS).

The aim of the invention is to offer a thin asymmetric security thread that creates various optical effects when viewed from different angles.

Another objective of the invention is to provide a thin protective device with high color saturation and good color management.

Another object of the invention is to provide a thin security thread comprising a demetallized hologram and hidden markers.

Another objective of the invention is to provide an image obtained by hot stamping and having multilayer security features.

Disclosure of invention

According to the present invention, there is provided a structure providing an optical effect and comprising a first substrate and a second substrate attached to the first substrate with only a binder material, where the binder material contains a binder that is activated by energizing and including a plurality of particles dispersed therein or onto mute, in order to create an optical effect that can be detected through the first substrate.

It is clear that the second substrate can be any object to which the first substrate can be attached, for example, by hot stamping.

According to another aspect of the present invention, a method for forming an article providing an optical effect is provided, said method comprising the following steps:

a) obtaining a first substrate having at least a first optical effect;

b) applying to the first substrate a carrier with particles that create an optical effect and located on or in the carrier, the particles providing a second optical effect detectable through the first substrate; and

c) bonding the first coated substrate to the second substrate or article by hot stamping, so that only the carrier is used as a binder in hot stamping.

Brief Description of the Drawings

Next, embodiments of the present invention will be described with reference to the accompanying drawings, in which:

figa is a schematic view of a protective product before performing hot stamping, according to the prior art;

fig.1b is a schematic view of the protective product shown in figa attached by hot stamping to a carrier substrate, according to the prior art;

figure 2 is a cross section of the foil corresponding to the invention and shown before transfer to the product, in which the substrate containing a layer of aluminum with a pattern also contains a lower layer of a dry binder material for hot stamping, in which there is a pigment with variable optical properties (PIOS) or magnetic pigment with varying optical properties distributed over a binder material;

figure 3 is a cross section of a chromatogram with a binder material with varying optical properties after transfer to a paper or cardboard substrate during hot stamping;

figure 4 - several different types of the same banknote, in which a hologram is attached to the substrate of the banknote and in which there is a binder material with varying optical properties as a binder material for hot stamping;

5 is a cross section of a chromatogram with a binder with varying optical properties and a layer with a high refractive index before transfer using hot stamping;

6 is a cross section of a chromatogram with a binder material with varying optical properties and pattern;

7 is a cross section of a device indicating unauthorized interference, before performing hot stamping;

Fig.8 is a cross section of the device of Fig.7, indicating unauthorized interference after hot stamping;

Fig.9 is a cross section of the device of Fig.7, indicating unauthorized interference after an attempt to remove;

figa is a cross section of a chromogram structure showing a binder material with a changing color and designed for hot stamping, and the layer of binder material lying on top contains hidden markers;

Fig. 10b is a security thread containing an ISMS and manufactured by rolling a demetallized hologram using two different layers of ISMS;

11 is a cross section of a chromogram structure showing an aluminum layer with a pattern and a binder material of a changing color for hot stamping, and a separate upper layer of a binder material containing hidden plates;

12 a is a cross-sectional view of a chromogram structure according to one embodiment of the present invention;

12b is a cross section of a chromatogram with a binder between a foil with variable optical properties (IOS) and a demetallized hologram;

figs is a cross section of a chromatogram with a colorless binder between the foil and a demetallized hologram, the binder containing hidden flakes or small concentrations of flakes with varying optical properties or magnetic flakes with varying optical properties;

Fig.12d is a cross section of a chromatogram with a binder material;

Fig. 13 is a cross-sectional view of a thin color-changing security thread;

Figures 14 and 15 are graphs used to compile formulas for estimating the amount of pigment applied;

Figs. 16 and 17 are graphs showing reflective abilities of images transferred during hot stamping;

Fig. 18 is a graphical representation of the absorption difference data;

Fig is a graph of measurements of the optical density of the grid;

Fig. 20 is a photograph of a security device attached to a casino chip using a transfer process of a binder material during hot stamping;

FIG. 21 is a cross-sectional view of an improved “synthetic thread”, wherein a multilayer security system creates several optical effects;

Fig is a set of photographs of a security thread according to the present invention;

FIG. 23 is a cross-sectional view of a multilayer security thread using an ISMS according to one embodiment of the present invention; FIG.

24 is a cross-sectional view of a security thread in which at least three layers of a binder material are used to connect two substrates;

FIG. 25 is a cross-sectional view of a security thread in which a substrate is manufactured using two different SMOS.

The implementation of the invention

In the present application, the term “binder material activated by energy supply” or “binder material activated by energy supply” means a binder material which requires an energy source to cure. Binding materials that are activated by energizing include, for example, hot stamping binders, ultraviolet-activated binders, thermoplastic and thermosetting binders, ink-based polymer compositions, varnishes and coloring compositions. For example, the binder material may be selected from the group consisting of polymethacrylate, polyacrylate, polyamide, nitrocellulose, alkyd polymer, polyvinyl alcohol, polyvinyl acetate and polyurethane.

Methods for activating binders include hot stamping, ultraviolet irradiation, heating, or the use of an electron beam. For brevity, a binder material that is activated by energizing, possibly containing special flakes, hereinafter will be referred to simply as a “binder material” if this does not lead to confusion.

As described previously in the prior art section, the hot stamping region is well known, in particular the bonding of one optical coating or substrate to another during hot stamping. For example, coated substrates bearing images, logos, or other signs are attached during hot stamping to lottery tickets, passports, banknotes, driver's licenses, poker chips and many other well-known products and substrates.

Although commercially available hot stamping binders have a function, the present inventors have noticed that some cured paints containing flakes with varying optical properties serve well as hot stamping binders. Note that this paint is no longer a paint, but acts as a binder, and therefore, the requirement or step of adding a layer of a binder material to a paint layer with varying optical properties is eliminated. Moreover, an additional advantage of the fact that in the binder material for hot stamping there are flakes that create special effects is to improve the structure. Also, this method can lead to finer structures, as well as structures with a layer of binder material with a pattern and structures containing more than one layer of binder material that provide more than one optical effect, for example, the presence of markers in one layer and PIOS in another layer.

Binder material can be printed in the form of a pattern or applied entirely over the entire surface. In the presence of a pattern, the product becomes more protected from unauthorized interference, since the product cannot be physically removed as a whole. Attempts to remove the device by dissolving the binder using solvents will also fail, since the solvent will also act on the hard coating / release layer, which in turn will destroy the device, making an attempt at unauthorized intervention obvious.

The size of the flakes can vary greatly, but it is preferable that their diameter or size across their surface is at least 5 microns. Flakes can be flakes with varying optical properties, color-changing flakes, thin-film interference flakes, diffractive flakes, reflective flakes, light-absorbing flakes, hidden flakes, flakes with symbols or signs, uniform flakes, magnetic flakes that change the color of pigments thin metal-dielectric films, fully dielectric pigments based on mica, liquid crystal pigments and so on.

The inventors also found that material with flakes, such as flakes with varying optical properties, diffractive, absorbing, or reflective, or flakes with other properties, such as hidden features, can be added directly to conventional hot stamping binders before curing, which is done in order to glue and provide optical effects that create added flakes.

Some of the devices described in this application contain light-transmitting or substantially transparent substrates that can be made of polyethylene terephthalate (PET), oriented polypropylene (OPP), or other suitable plastic materials. For example, the thickness of the PET layer is from 6 to 25 microns. It should be understood that the device description contains only one substrate, the second substrate may be a protective coating, a release coating or any document or object to which the first substrate can be attached, for example, a paper document or a separate polymer film.

An optical array, also called an interference array, comprises a reflective layer, an absorbent layer and a dielectric layer located between the reflective and absorbent layers, as is known in the art. The reflective layer can be made of any metal with a reflectance of more than 20%, preferably aluminum. For example, the dielectric layer is made of MgF ₂ or another transparent material, as is known in the art.

The absorbent layer can be a gray metal with an n / k ratio of about 1, where n is the real part of the refractive index and k is the imaginary part of the refractive index, for example, Cr, Ti or Ni, or it can be a non-selective absorbing layer of the visible spectrum, for example TiN or can be cermet, as described in the article entitled “The influence of metal clusters, the sizes of which are expressed in nanometers, on the generation of strong colors and the control of their properties during physical vapor deposition (PPO)”, a torus R. Domnick et al., 49th Annual Technical Conference Proceedings (2006), Society of Vacuum Coaters, incorporated herein by reference. By way of example, the cermet material contains silver regions in the dielectric matrix.

Some of the devices described in this application contain a diffraction structure, which can be any relief, including a hologram, a demetallized hologram, a cinemagram and a zero-order diffraction structure or a simple lattice structure. The polymer on which the image can be extruded can be made of materials such as type G PET, polycarbonate, polyvinyl chloride or polymethacrylate. A layer on which an image can be extruded can be combined with a hard coating layer / separation layer. The extrusion may be continuous or contain a pattern. The demetallized layer can be made of Al, Cu, Ni or other metals or metal alloys in the form of a pattern created by demetallization. Various technologies can be used to apply the metal layer in the form of a pattern, such as chemical etching or oil burning in a vacuum, both technologies are applied with alignment of the relief image. The high refractive index layer can be made of ZnS, TiO ₂ , ZrO _2, and so on.

In one embodiment of the present invention, ink particles are added to the binder to modify the effect of changing optical properties. Optionally, the binder layer can be transparent or translucent and the concentration of pigment particles can be adjusted so that when the protective article is attached to the printed document during hot stamping, the feature printed on the document can be seen through said protective article.

In one embodiment of the present invention, colorless reflective flakes are added to the binder, so that when reflecting the color of a paint from a binder or paint or ink used as a binder, it seems that the flakes have a color, it is preferred that the ink is made on acrylic or urethane base with flakes contained in them.

Another embodiment of the present invention is a single layer of a binder material with particles providing an optical effect therein. For example, the particles are color-changing flakes. This structure can be used to connect two objects together, while one of the objects transmits light in order to make visible the optical effects created by the bonding material.

In another embodiment of the present invention, reflective flakes, characters or text are added to the binder material, as described in CITA patent application, publication number 20060035080. When viewed under a microscope in reflected light, these characters “protrude” from a colored background.

In another embodiment of the present invention, the protective device comprises two bonding layers: the first layer of the binder material does not contain paint, but contains reflective flakes, the second layer of the binder material is painted with paint, so that the paint dampens or improves the reflectivity of the first layer, depending on which side you are looking at the protective device.

In other embodiments of the present invention, ultraviolet-activated fluorescent paints or pigments that are converted with increasing frequency and which fluoresce when exposed to infrared radiation, for example, due to two-photon absorption, are added to the binder as a hidden feature. Nanoparticles, or transparent conductive particles, for example, indium and tin oxide flakes (OIO), can also be added to the binder material as a hidden feature.

In a less preferred embodiment of the present invention, the binder material is first deposited on the substrate, and then pigment particles with varying optical properties (PIEC) are added to it, for example, by spraying or scattering an air stream onto the surface of the binder material, and then, if desired, is applied additional binder material, so that the translucent PIOS layer is visible in the transferred product.

Although a stamp with an image formed therein is used in some embodiments, an image may alternatively be created as a demetallized hologram. In this example, a hot stamping stamp is used to transfer the image during hot stamping. The transferred image may be square or other shape defined by a flat hot stamp or the area of the binder.

An alternative to hot stamping a binder onto a demetallized hologram is to print a UV-activated binder material containing PIOS particles, place a multilayer sheet with a demetallized hologram on the binder and cure the binder with ultraviolet light passing through the transparent back layer for the sheet with the binder material, or under the influence of a beam of electrons passing through a demetallized hologram using the step of curing by an electron beam. Ultraviolet will not act through areas of the hologram that are not demetallized unless the width of the non-demetallized regions is very small, less than 2 microns, so that ultraviolet light can cure the binder material at an angle.

2 shows a structure according to one embodiment of the present invention. An aluminum layer 102 is contained on the extruded hologram layer 100. The opaque aluminum coating 102 is patterned and forms windows or spaces. Both the opaque aluminum regions 102 and the gaps between them are coated with a binder material 104 with varying optical properties, inside the binder material there are flakes 105 with varying optical properties, which can be magnetic pigment flakes that change color depending on the viewing angle. The polymer layer 106 is made in order to extrude the embossed surface 100, and the separation layer 108 (or a hard coating layer) is deposited on a removable carrier substrate 110, usually made of PET, with a thickness of 10 to 25. In another embodiment, the polymer layer and the separation layer / layer of hard coating combined into one layer.

Figure 3 shows the structure of figure 2 after hot stamping on a paper or cardboard substrate 112. When the layer 110 of PET is removed, when viewed on the structure from top to bottom, through hard coating 108, through aluminum holographic layers with a pattern, you can see through the windows color-changing coating. The synergy effect, which is obtained due to the combination of pigments with special effects in a binder material, makes this structure almost ideal, without increasing the thickness of the color-changing layer. The total thickness is less than 20 microns, usually about 10 microns.

FIG. 4 is a photograph of a portion of a Chinese banknote in which the structure shown in FIG. 2 is transferred by hot stamping onto the banknote paper. This structure contains a hologram manufactured by Hologram Industries, Paris, France, and provides color-changing effects, that is, color changes when the angle of view is changed. For example, the color of the square background changes from the indigo indicated by arrow 301, through purple - arrow 302, to dark pink, indicated by arrow 303.

The product after hot stamping (HT) is characterized by a greater color saturation than its prototype with ink, since the flakes quickly precipitate in a binder with low viscosity on a smooth substrate. Printed PIOS has less color saturation since the person is looking at the side of the ink that has been disconnected from the coating device. When the ink line is interrupted, ink clots flow off a relatively rough surface compared to the boundary between the plastic substrate and the ink. That's why hot stamping produces better color saturation than when printed on the surface.

The device shown in figure 4, contains at least five security elements: 1) a hologram with a double image - the number "25" in the center of the hologram appears at a certain viewing angle and is not visible at other viewing angles, 2) an easily remembered image Venus Milosskaya, 3) the hologram contains a demetallized aluminum layer in a lace pattern, 4) a color change and 5) hidden images that can be seen with a hundredfold or greater magnification.

An alternative embodiment of the invention is shown in FIG. 5, where the high refractive index layer 114 is located between the variable optical properties binder layer 104 and the patterned aluminum layer 102. A high refractive index layer 114 made of a material such as ZnS, TiO ₂ or ZrO ₂ is located above the demetallized holographic film. In this example, a layer 114 with a large refractive index allows you to see the diffraction or holographic surface 100 simultaneously with the binder material 104 with varying optical properties. A large refractive index prevents the coincidence of optical performance between the binder material and extruded in the polymer layer.

An alternative embodiment of the invention is shown in FIG. 6, where a binder layer 104 with varying optical properties is imprinted between the windows of aluminum 102, so that the transferred device will have the property of indicating unauthorized interference. If someone tries to remove the device, then it will collapse in areas in some of which there is bonding material, while in others it is not.

According to another embodiment of the present invention, shown in Fig.7-9, the device comprises a separation layer 108 with a pattern placed on the substrate, the polymer layer 106, firmly connected to the substrate. The device is continuously coated over a layer 102 of demetallized aluminum (through the windows of this layer and between them) with a binding material 104 with an IOS containing flakes 105. In Fig. 7, the device is shown before being connected during hot stamping to a carrier 66 to be protected. During operation, the device is so attached to the surface 66, as shown in Fig, and the binder material 104 is activated by hot stamping. If someone is trying to separate the device from the media, then the separation layer 108 is only separated in the pattern, while leaving the back of the pattern on the substrate 66. The result of such an attempt is shown in FIG. 9, where an arrow 120 marks an uneven rupture of the binder material. In essence, this device is a security tag indicating unauthorized interference.

The following embodiments of the present invention are chromograms containing two different layers of a binder material with varying optical properties, activated when energized and designed to create at least two different optical effects, where one of the binder materials may contain hidden marking flakes, referred to in technique markers.

In the embodiment of the invention shown in Fig. 10a, the chromogram contains a hologram that can be demetallized, or a layer with a high refractive index or a surface with a different type of relief and a binder material made of two separate layers. One of the layers of binder material for hot stamping, namely layer 119, contains hidden materials, in this example, it is hidden flakes 118, and the other layer 104 of binder material for hot stamping contains pigment 105 with varying optical properties. The present invention provides a carrier for the efficient use of expensive hidden materials. Examples of hidden flakes 118 are, but are not limited to, the markers described in U.S. Patent Application Publication Number 2006/0035080, incorporated herein by reference, certain form pigments, magnetic flakes, fluorescent pigments typically activated by ultraviolet to produce visible light, or specialized anti-stokes infrared activated materials to produce visible light. Hidden materials are located in a thin layer of binder material 119, on which a layer 104 of a binder material containing color-changing pigments, for example a thin metal-dielectric film, two dielectrics, mica-based pigments, liquid crystal pigments, and so on, is applied. Under normal conditions, hidden materials are not visible, but they are easy to detect, for example, in ultraviolet light or under a microscope, or using magnetic or infrared detectors. When a chromogram is attached to a document or other object requiring protection, a layer of PET with a thickness of 12-25 microns, usually 19 microns, is removed, leaving a very thin layer of a protective device on the document whose thickness is not more than 20 microns.

An alternative embodiment of the invention is shown in FIG. An aluminum layer 102 with a pattern located on a PET substrate is attached to another PET substrate coated with a binder with varying optical properties. An aluminum pattern may contain an image of text, characters, barcodes, or even photographic images. A pattern is formed on the aluminum layer using the demetallization process (laser ablation, chemical etching or oil ablation of a flexographic printing image in a vacuum machine). In the case of photographic images obtained using the oil ablation process, resolutions of up to 70 microns (≈180 dpi) can be achieved. Oil ablation is the preferred method of demetallization, as the aluminum layer with the pattern is obtained in the form of a line, in vacuum during one technological stage. The binder material with varying optical properties contains at least two separate layers of binder material: one layer of binder material 104 includes color-changing pigments 105, and the other layer 119 of binder material includes hidden materials 118. The above forms a protective thread. In this case, the thickness of each PET layer is about 5-10 microns, so that the total thickness is 20 microns or less. This limitation of thickness is necessary for the security thread so that in the bundle of banknotes one end of the bundle is not thicker than the other end.

In another embodiment of the present invention shown in FIG. 10b, a two-coating process is used to bond two transparent substrates together. First, a binder material with varying optical properties is sequentially applied to a demetallized hologram: a first binder coating 130 with varying optical properties, magnetic or non-magnetic, and a second coating 131 of another binder with varying optical properties. For example, the first coating changes color from gold to green, and the second coating changes color from blue to red. Next, the substrate 110, transparent or translucent, is bonded using a hot pressure roller with a binder material 130. After that, the second substrate supporting the hologram (not shown) is removed, leaving the protective layer 106. The final product has various color-changing effects, depending on side from which they look at him. In other embodiments, one of the coatings does not change color and / or contains hidden features.

11 shows an additional embodiment of the invention, which is a structure in which a binder with varying optical properties is used to join two parts of transparent PET to produce a color-changing security thread. When viewing such a structure on one side (top to bottom in FIG. 11), you can see an image formed by a demetallized hologram and a color change in addition to latent, for example, fluorescent, images. When viewed from the other side, in the case of applying high concentrations of opaque pigments, only a color change can be seen. For example, interference pigments based on a metal-dielectric with a concentration of more than 10% pigments by weight of the total weight of solid pigment particles plus a binder create such an effect. In this embodiment, there is no separation layer, and a metal layer with a pattern and latent images are optional.

In one embodiment of the present invention, a binder material with color-changing flakes is used as a multilayer binder material, which makes it possible to produce a thin security thread having the properties of a device with variable optical properties (UIOS). For example, a web with a thickness of 6-10 microns is coated with a binder with variable optical properties (SMOS), which is a thermosetting binder or a dried urethane binder containing particles with IOS, and then pressed to a multilayer sheet at high temperature to another 6-10 micron thick web. Then this sheet is cut into protective strips with a width of 2-5 mm. These values are common for use in banknotes. In essence, due to the low viscosity of the binder, a synthetic foil is created during the application of the first coating and then during the pressing process. When performing both processes, the flakes tend to align and settle flat to the surfaces of the canvases.

In one embodiment of the present invention, printed information and a transparent substrate made of, for example, PET and containing ink are added to the substrate layer to color or bind the binder material with varying optical properties on the substrate, or weaken the color of the material. If desired, a demetallized chromatogram is applied to the binder layer using a pinch roller.

According to another embodiment of the present invention, the structure shown in FIG. 12a comprises a polymer layer 106 with extruded relief 100, but does not have a separation layer. The relief 100 is coated with a demetallized aluminum layer 102 and two layers of binder 104 and 119 with different flakes 105 and 118. For example, flakes 118 are hidden flakes, markers and flakes 105, designed to create a color change effect. Alternatively, the substrate 110 itself may be a layer in which extrusion can be performed. Materials such as type G PET, polycarbonate, polyvinyl chloride or polymethacrylate are suitable for the substrate 110 in which extrusion can be performed. This structure may be useful as a protective label, so that the layer 104 can be attached to the outside of the box or package.

In one embodiment of the present invention, the demetallized hologram is first coated with markers located in a binder, and then further coated with a binder with IOS. In this double overlay method, fewer markers are used and markers are better visible than methods known in the art when markers are distributed throughout the ink medium with varying optical properties and many markers are obscured by the opaque particles with IOS lying above. It is preferred that the ink with variable optical properties have an acrylic or urethane carrier.

In one embodiment of the present invention, the first layer of binder material is discontinuous. For example, a first thin layer of a carrier of a relatively low viscosity binder is printed on the substrate in the form of dots. Markers or other flakes are located in the carrier with a high density, and the carrier is coated with a second layer of a less expensive binder material, providing an additional optical effect.

In another embodiment shown in FIG. 13, the structure comprises a PET layer 110, possibly an extruded polymer layer 106, an aluminum demetallized layer 102, two binder layers 104 and 119, and a protective hard coating layer 108, i.e., a protective solid / release layer the layer took the place of the second PET layer. Thus, the entire structure of the type of protective thread can be quite thin, for example, 15 microns thick when using a 9 micron thick PET layer that is designed to extrude or to arrange the varnish / polymer layer 106 to extrude. For example, this structure is made by pressing at high temperature a PET with a demetallized hologram or just PET with aluminum with a pattern to a detachable layer of PET coated with layers of a binder material containing color-changing and hidden materials. Next, the detachable PET layer is removed, and the hard coating layer 108 remains on the structure as shown. Alternatively, a demetallized hologram on a PET substrate is periodically processed in several gravure printing sections, including two printing sections for layers 119 and 104 of a binder material and a printing section for a protective hard layer. Between the printing sections are drying sections.

In the following embodiments, the IOS foil comprises a demetallized hologram, and a binder with IOS is located between the foil and the demetallized hologram.

In yet another embodiment of FIG. 12b, the first substrate 222 is coated with a reflective layer 220a, a dielectric layer 220b, and an absorbent layer 220c, which together form a color-changing foil 223 with varying optical properties. The substrate 212, which is a polymer / hardcoat layer, contains a hologram and is partially covered with a pattern of aluminum layer 216, with a high reflection coefficient, this layer is aligned with the hologram to prevent light from passing through it. As a result, the substrate 212 contains one or more regions 100 extruded and coated with demetallized aluminum. Substrate 212, if desired, may contain one or more regions 214 extruded but not coated with aluminum. The polymer layer 212 is optionally coated with a protective light-conducting layer 218, on which an opaque sign 219 is printed. A demetallized hologram is applied using hot stamping or a hot pinch roller to an optical set using a transparent binder material 230 for hot stamping.

Shown in fig.12d layer of a binder material with particles of IOS can be used in another embodiment of the invention as shown in fig.2d. This embodiment is in many respects similar to that shown in FIG. 12b, however, it contains a first substrate, preferably made of PET, coated with color-changing flakes 235 located in the carrier 234, adhesive ink on an acrylic or urethane base, which during hot stamping transferred to the same upper structure as in fig. 12b. After drying and curing of the ink and thus forming a color-changing coating, a hot stamping binder 230 is applied and cured. To form a chromogram, a first coated substrate containing a binder material 230 for hot stamping is attached to a second substrate coated with the same layers as in the embodiment shown in FIG. 12b.

In yet another embodiment shown in FIG. 12c, hidden flakes 245 bearing a feature that cannot be seen with the naked eye are mixed in the hot stamping layer 240 and used to join the two structures together, as in the previous embodiments. In this embodiment, the effects of color changes that can be seen through windows where there is no aluminum coating, and hidden flakes 245, which can be seen with magnification, are used for authentication. Instead of hidden flakes, small concentrations of flakes with varying optical properties can be used so that the colors of the IOS foil change when viewed from above.

The specified manufacturing process allows to produce the first and second substrates in two different places and store them in rolls intended for combining.

The present invention is practiced as follows. The binder material is diluted to proper strength by the addition of toluene and is applied using a reversing device for coating the corrugated roller, equipped with drying ovens. The consumption of binder material is 1.5-10 g / m ² , the latent pigment is applied at a rate of 0.005 and 0.05 g / m ² , and the color-changing pigment with OIC is 1-10 g / m ² . Two pigments with varying optical properties were selected for a series of devices: a set whose color changes from red to green and which has a period of two, that is, P / D / P / D / O / D / P / D / P and an optical set whose color changes from blue to red and which has a period equal to unity, that is, P / D / O / D / P, where P is an absorbing material of Cr, D is an insulator of MgF ₂ , and O is a reflective material of aluminum. Two different hidden markers were used: a 10 micron square pigment with a € symbol in the center and a 30 micron square pigment with a $ symbol in the center. The press speed was approximately 20 feet per minute (6 m / min).

Experiment Results

Experiments have been carried out consisting in the introduction of pigment with variable optical properties (PIOS) in commercially available binder materials for hot stamping. The thickness of the binder material for hot stamping ranged from 3 microns to 10 microns, preferably 3-7 microns.

To evaluate the dependence of the mass of pigment used in the binder material for hot stamping (SMHT), on their optical density, formulas were developed. It was found that, in general, the pigment / SMHT optical density should be about 0.3 or more against a black background to obtain optical characteristics that are close to those of coatings with an optical density of about 0.6 against a white background.

In the tests, a series of hot-bonding binder and mixtures of hot-bonding binder with pigment was applied to a 19 micron thick polyester film with a separation layer and a chromogram layer.

Coating of the binder material was performed on a dissolving device for coating with a roller whose width was 10 inches (25 cm) and the length of the drying oven was 100 feet (30 m). Binder material was applied using roll reverse gravure printing.

The pigments were mixed into an industrial hot-melt adhesive and mixed continuously before being placed in the coating bath. Toluene was used to dilute the composition. Liquefaction is necessary to obtain samples with a lower coating weight. Right before being added to the coating bath, a sample was taken from the binder to determine the percentage of solids. The weight of the applied binder material was obtained as follows: the known area of the coated web was weighed, the binder material was removed with a solvent, the web was dried and weighed after removing the binder material. To determine the weight of each coating, three samples were taken over the entire canvas and to obtain the weight of the coating, the obtained values were averaged. After passing each sample, the anilox rollers were cleaned. For most experiments, an anilox roll of 75 TH (Trihelical) was used. To increase the amount of applied binder material, an anilox roll of 55 TH with two coatings was used.

The first four coatings did not contain pigment and were applied at two different levels of dilution. These coatings were used to determine the optimum coating weight for acceptable transfer during hot stamping. It is known in the art that the thickness of a binder material can vary over a wide range. As an example, in order to obtain the optimal coating thickness from a binder material, conditions were selected calculated from density measurements in g / m ² under which the layer thickness of the binder material without pigment was 3-3.5 microns.

Each of the coated web samples was evaluated for embossing performance and optical density. For all samples, transfers were carried out using hot stamping. The optimal embossing conditions for transfer using a Kenson hot stamping press with a rectangular brass stamp of size 35 mm × 22 mm were as follows: temperature from 100 ° C to 125 ° C, holding time - 0.5-1.0 seconds. The pressure was adjusted so as to take the lowest operating value in order to minimize the extrusion of the pattern on the evaluated samples. The rim was very small for all samples. Hot stamping transfers of each sample were done on the black and white areas of Leneta cards. The transfers were carried out at a temperature of 100 ° C and a holding time of 1.0 s. For each transfer for black and white backgrounds, reflectance values were obtained and color changes measured.

Optical densities were measured on transparent areas of the web.

The properties of the web coated with a binder are summarized in tables 1 and 2.

The optical density (OD) of the binder containing the pigment was used to estimate the amount of pigment on the web. This was done to determine if it could be used as a competitive analytical procedure for setting the technical conditions for applying a binder / pigment. If the ratio of pigment to binder is known for any composition, then the optical density of the coating of the binder can be used to determine the amount of binder used for any transparent web. On Fig depicts the dependence of the optical density of a strong red color on the weight per unit area of a strong red color. This dependence was used to obtain the formula for a strong red color. On a separate graph, shown in Fig.14, shows the dependence of all optical densities on the weight of the pigment in grams per square meter. According to these data, the second formula is obtained. The formulas are very similar, regardless of differences in pigment mass per unit area. There is probably a deviation in the overall dataset due to pigment deposition and the fact that 3 of the 4 tested pigments are characterized by a similar pigment mass per unit area. These factors can lead to the fact that the formulas produce slightly larger masses of pigment per unit area.

The following formulas were obtained for estimating the amount of pigment applied:

The number of grams of pigment deposited = 0.1351465523379770 × (optical density of the coated film) + 0.0591124749175451;

The number of grams of deposited highly red pigment per square meter = 0.135546396874281 × (optical density of the coated film) + 0.05.

Table 3 compares the measured absorbance of the coating with the absorbance calculated using the above formula. Due to the relatively small differences between the measured OD and the calculated OD (as shown in table 3), the optical density of the coating of the binder material can be used to determine the amount of binder material used for any transparent web with a known ratio of pigment to binder material.

16 and 17 show reflectance values of images transferred to white and black areas of Leneta cards, respectively. The data shown in FIGS. 16 and 17 were converted for absorption, and the absorption values for the white areas were subtracted from the corresponding absorption values for the black areas. A graphical representation of the absorption difference data is shown in FIG. Samples with the smallest difference between black and white absorption values have the best performance. Samples with the best performance are those with the highest pigment content.

On Fig shows the measurement of optical density made over the entire canvas. 5 measurements were made across each sheet at equal distances. These data show that the coating thickness changes by less than 5% up or down in all cases of a binder with a pigment.

Table 4 contains experimental data, where “Marker L” means a low concentration of markers, and “Marker H” means a high concentration of markers.

On Fig shows a photograph of a protective device deposited using the process of transferring a binder material during hot stamping, as described above. In said protective device, the hidden flakes carry the € symbol, and the $ symbol is located in the binder material on the flakes, which change color from blue to red and are located in the second layer of the binder material. Here, the poker chip contains a holographic image of Venus de Milo on the background of color-changing scales. Hidden scales can be seen at a hundredfold magnification, and without an increase they are not visible. This embodiment of the invention combines color change, holographic effects and hidden characters using flakes with special effects in the binder.

To make the chips described above, rolls coated with a binder material are cut to a length of 8.26 centimeters wide so that two rolls: a hologram / binder material OIP, i.e. chromograms, can be simultaneously applied by hot stamping. To transfer the chromatogram to poker chips made from acrylonitrile butadiene styrene (ABS) copolymer, a Malahide hot stamping machine, model E4-PK, was used. The stamp is made of silicone rubber and heated to approximately 191 ° C.

About 100 prints were continuously printed at a productivity of 450-500 prints per hour. The transferred elements had good adhesion when scraping with a fingernail, and the edging was very small. The performance characteristics of the chromogram foil are similar to those for industrial hot stamping foils. In practice, hidden images show either the value of banknotes, poker chips or a logo, a symbol of the medium or company that issued such documents.

In the case of using a transparent hidden pigment and a transparent color-changing pigment in a transparent binder, an additional security element is introduced so that the observer can also see through the device the printed information contained on the document.

Embodiments of improved “synthetic filaments” in which a plurality of optical effects are created by a multilayer security system will be described below.

21, the security thread comprises a substrate 110, a reflective layer 102b, a binder layer 130 with variable optical properties, another binder material layer 132 containing markers, a relief structure 100 coated with a demetallized aluminum layer 102a, and a polymer layer 106. It is preferred that the substrate 110 was made of PET, however, oriented polypropylene (OPP) or other suitable plastic materials can be used. The substrate may also be continuously colored or patterned.

The reflection layer 102b is preferably made of aluminum and contains windows so that the optical effect provided by the layer 130 can be seen through the substrate 110 and the reflection layer 102b. If desired, the windows in the layer 102b are made in the form of letters or other signs so that the color-changing the text could be seen through the substrate 110.

Alternatively, instead of a pattern layer 102b that is located inside the structure, the substrate 110 may comprise an aluminum layer with the pattern directed outward, while the inner PET border is in contact with the layer 130. In the case where the reflective aluminum layer with the pattern is directed an additional protective layer, such as a vacuum-deposited SiO ₂ layer or an organic polymer protective layer, may be located on the outside of the device, above the reflective material.

The binder material 130 with varying optical properties is preferably made of a color-changing binder material, which can be adjusted so that the color change ΔE from one sample to another, defined as the square root of the sum of the square of the color difference, the square of the difference in saturations and the square of the difference in brightness, is less 1.0, using a color-adding mixture of pigments with varying optical properties. However, in general, in the field of protection, an ΔE value of less than 3.0 is acceptable. This degree of color management cannot be achieved with foils with varying optical properties, since it is not possible to adjust the color by adding pigments. If desired, other materials, such as fluorescent materials, phosphorescent and anti-Stokes materials, paints and other dyes, can be added to the binder with IOS.

A binder layer 132 containing markers or pigment flakes is substantially transparent so that the effects provided by the IOS binder layer 130 are visible through the layer 132. The binder layer 132 may be colorless or color. Either the markers themselves are transparent or their concentration is sufficiently small, so that the visibility of the binder layer 130 is ensured.

If desired, magnetic flakes, such as metal flakes or IOS flakes with a magnetic layer located between two layers of reflective material, are added to the binder material from layers 130 and 132, possibly in combination with non-magnetic flakes with varying optical properties.

The relief structure 100 is pressed into the polymer layer 106, coated with a demetallized layer 102a, and provides a demetallized holographic effect, and contains elements such as a double-image hologram, zero-order hologram, cinegram or other diffraction-based image acquisition method. The demetallized layer 102a contains a pattern in order to ensure the visibility of the SMIOS layer when the security thread shown in FIG. 21 is viewed from above. Layer 102a or 102b may contain a lace pattern of thin lines to provide additional protection against fake and / or may contain a feature 133a.

An image familiar to most people, such as the famous sculpture of David and Venus of Milos, famous structures, including the Eiffel Tower and the Great Wall of China, famous people, such as Einstein, can be a zero-order diffraction image. This allows ordinary people to recognize and remember the protective device and identify it through a combination of the image and the associated color change.

The thread is protected on both sides, on one side by a substrate 110, and on the other by a layer of hard coating / polymer.

If you look at the thread from one side, from the top, as shown in Fig. 21, you can see the color change effect of layer 130, a double-image hologram or zero-order hologram 100, demetallized aluminum lace layer 102a with a sign 13 3a and hidden signs, such as "Markers". Looking at the yarn from the other side, a color-changing pattern showing the color-changing background 130 is visible through the windows of the layer 102b surrounded by reflective aluminum 102b.

It is useful that the total thickness of the filament described above can be so thin that it is 12 microns if the filament is made of hot stamping foil, which is 6 microns thick and which is attached to a 6 micron thick PET layer. Earlier in such a thin thread, so many protective effects could not be obtained.

Another advantage of the thread described above is the large number of technologies used in the manufacture of this thread. This makes it difficult to fake, because for a successful fake, the fake person must have a lot of skills. A holographic structure, a pigment with varying optical properties and a demetallized aluminum layer on PET can be manufactured separately and, possibly, in distant places, and then reduced to the place of production of banknotes in order to produce the final product. SMIPS connects all components together. The idea of putting together the components immediately before placing the security device in paper for the manufacture of banknotes increases the protective properties of the device, since if the fake person intercepts one component during delivery, he will become the owner of only one component from the entire device. If desired, these prefabricated components contain alignment symbols, for example, in the aluminum layer 102b and in the demetallized hologram 100 and 102a.

Moreover, thin lines of a demetallized layer, such as a lace pattern, in a hologram make it difficult to fake a pattern using scissors, cutting out or even using photopolymers, since in the process of demetallization it is necessary to precisely combine demetallized patterns with topographic features.

Additionally, the cost of applying text or other images to the aluminum layer next to PET is very low, since the existing demetallization process by oil ablation can be used. You can achieve resolutions up to 70 microns.

Such security threads can be used in banknotes as window systems when the thread is woven into paper and is visible in windows on each side of the banknote. It can also be embedded in the paper itself when the paper above the thread is thin and transparent enough so that you can see the security features. The thread described above can be used in checks, passports and other secure paper documents and plastic documents, such as plastic-based banknotes, credit cards and ID cards. It can also be used as tearing thread in products such as cigarette packs and other protective packaging. In the case of paper documents, viewing from both sides is influenced by the fact that the thread comes to the surface of each side at constant or non-constant intervals or in the same place if there is no paper in it.

On Fig shows photographs of a security thread described with reference to Fig.21.

FIG. 23 shows a security thread using an ISMS and corresponding to another embodiment of the present invention. The thread contains two light-conductive substrates, preferably made of PET, which are connected by an OSI layer 104, in which there are flakes 105 with varying optical properties and hidden markers 118.

Another embodiment of the present invention is shown in FIG. 24 and is a security thread in which at least three layers of binder material are used to join the two substrates. The central layer of the ISMOS contains a carrier 104 and pigment flakes 105 and two layers of binder material with markers 118 located therein. These layers are located symmetrically between the two substrates.

Another embodiment of the present invention is shown in FIG. 25, where the security thread comprises a substrate 110 connected to two different SMOS. The embossed structure 100 is coated with a demetallized aluminum layer 102 and a hard coating / polymer layer 106. To produce such a protective thread, a chromogram is applied to each side of a substrate made of PET or other plastic during hot stamping or pressing by rollers, which is a demetallized hologram with an ISMS in which two ISMS differ in color and the effect of a color change.

The current prior art does not describe so thin security threads with SMIOS, which provides the manufacture of a multilayer system that resists counterfeiting, as the threads described with reference to Fig.21-25.

In particular, unlike the aforementioned US patent No. 4186943, the present invention is not symmetrical so that the thread looks different on each side, thereby providing an additional security element.

Also, the present invention improved color change compared to US patent No. 7054042, which is done by mixing slightly different amounts of pigment with varying optical properties in order to obtain accurate color and color change to obtain a ΔE value of at least 1.0 to 3.0 . A person is able to recognize such a color change. Table 5 shows the change calculated for such a Fabry-Perot thin film foil when normal white light falls for a structure containing an opaque aluminum layer, a low refractive index MgF ₂ layer and a 3 micron thick Cr absorption layer.

The structure of the yarn described in the present invention also makes it possible to add hidden materials (hidden plates or other pigments), which cannot be done for the yarn from the '042 patent. Moreover, although the pattern of opaque aluminum is mentioned in the '042 patent, it does not lead to windows with a color change in the aluminum pattern, which happens in our invention. The removal of a certain amount of aluminum in the Fabry-Perot filter described in the '042 patent results in colorless windows, since the Fabry-Perot resonator is destroyed. Moreover, the device described in the '042 patent is intended to be viewed from only one side.

Compared with US Pat. No. 5,700,550, the invention in this application provides a greater level of color and color saturation control regardless of the color of the substrate to which the device is attached, and this application describes the addition of hidden markers to the device.

Compared to U.S. Patent Application Publication Number 2005/0127663, the present invention provides better color management for the SMEOS and the thin film layer of PET, since it can be easily rolled with the SMEOS.

Although the invention has been described with reference to illustrative embodiments, this description is not to be understood as limiting the invention. It is clear that a person skilled in the art in this field can offer various modifications and combinations of the described embodiments, as well as other embodiments of the invention, without going beyond the scope of the invention defined in the attached claims.

Therefore, it is understood that the appended claims embody all such modifications or embodiments as are within the scope of the invention.

Claims (22)

1. A structure providing an optically variable effect comprising a first substrate and a second substrate attached to the first substrate using only a hot stamping binder, the hot stamping binder containing an energized binder that contains a plurality of color-changing particles distributed in the substance, to provide an optically variable effect detected through the first substrate, and color-changing particles change color when the angle of pa denia of light. 2. The structure according to claim 1, in which the first substrate has a relief structure, and an optically variable effect provided by a plurality of color-changing particles can be visually detected externally through a diffractive structure. 3. The structure according to claim 2, in which the relief structure is a diffraction structure selected from the following group: hologram, demetallized hologram, cinegram, zero order diffraction structure and lattice structure. 4. The structure according to claim 3, in which the diffraction structure is visible simultaneously with the optically variable effect provided by color-changing particles. 5. The structure according to claim 2, in which the first substrate has a layer with a high refractive index located between the diffraction structure and the binder material for hot stamping. 6. The structure according to claim 1, in which either the first or second substrate has a thin-film interference set, and / or a reflective coating, and / or a coating with a high refractive index, and / or a separation layer with a pattern on it. 7. The structure according to claim 1, in which the binder, activated by the supply of energy, is activated by hot stamping, heat or an electron beam. 8. The structure according to claim 1, in which the binder, activated when energized, is selected from the following group: polymethacrylate, polyacrylate, polyamide, nitrocellulose, alkyd polymer, polyvinyl alcohol, polyvinyl acetate and polyurethane. 9. The structure of claim 1, wherein the optically variable effect provided by the plurality of color-changing particles is detected by the human eye. 10. The structure of claim 1, wherein said plurality of color-changing particles comprises magnetic material particles and / or dye particles and / or flakes having a length of at least 2 microns. 11. The structure of claim 1, wherein the plurality of color-changing particles comprises flakes of at least 2 microns in length, the flakes being flakes with optically variable properties, and / or thin-film interference flakes, and / or diffractive flakes, and / or reflective scales, and / or light absorbing scales, and / or hidden scales, and / or scales carrying symbols or a sign, and / or scales of the same shape, and / or magnetic scales, and / or metal-dielectric scales, and / or completely dielectric flakes and / or flakes based Luda and / or flakes based on liquid crystals. 12. The structure according to claim 1, in which either the first or second substrate is a light transmitting substrate, or essentially a transparent substrate, or a PET substrate, or a coating with a high refractive index, or a protective coating, or a release coating, or a piece of paper. 13. The structure according to claim 1, in which the first substrate has at least one region that is not attached to the second substrate using a binder material for hot stamping. 14. The structure according to claim 1, in which the binder material contains the first and second sublayers of the binder material for hot stamping. 15. The structure according to claim 1, in which the binder material is characterized by a color change ΔE from one sample to another, and ΔE is about 5.0 or less. 16. The structure according to claim 1, characterized in that it forms a protective thread. 17. The method of forming a structure according to claim 1, containing stages in which:
a) get the first substrate, on which is located a binder that is activated by applying energy, moreover, the binder, activated by applying energy, contains many color-changing particles distributed in the specified substance, to provide an optically variable effect detected through the first substrate, and changing the color of the particles changes color when the angle of incidence of light changes,
b) the first substrate is placed next to the second substrate, without adding a binder between them, so that the binder activated when the energy is supplied is located between the first and second substrates; and
C) curing the binder, activated by the supply of energy through hot stamping. 18. The method according to 17, in which at step (b), at least one region of the second substrate is not covered with a binder that is activated by applying energy, so that in step (c), this region is not bonded to the first substrate. 19. The method according to 17, in which, in step (a), the first substrate is coated with a first binder that is activated by energizing, containing the first particles distributed in the specified substance, and then coated with a second binder that is activated by energizing, containing the second particles distributed in said substance, wherein the first particles and the second particles are color-changing particles and the first particles are different from the second particles. 20. The method according to 17, in which, in step (a), the binder activated upon energizing is first applied to the first substrate, then said particles are added to the surface of the binder activated upon energizing, and then the added particles are coated with additional binder substances activated by the supply of energy. 21. The method according to 17, in which the diffraction structure is located on the first substrate. 22. A method of forming an article to provide an optically variable effect, comprising the steps of:
a) get the first substrate
b) a carrier is applied to the first substrate, containing color-changing particles therein to provide an optically variable effect detected through the first substrate, the color-changing particles changing color when the angle of incidence of light changes, and
C) connect the first coated substrate with the second substrate or product by hot stamping, and only the specified carrier is used as a binder material for hot stamping.

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