RU2743283C1 - Holographic element for security labels and tapes - Google Patents

Abstract

FIELD: security labels and tapes.SUBSTANCE: invention relates to the field of security labels, as well as protective sealing and packaging tapes with indicators of unauthorized access (interference). The problem is solved by introducing holographic elements containing transparent multilayer thin-film color-variable structures into the structure of security labels and tapes. The introduction of such structures into holographic elements increases the clarity, contrast and brightness of the monitored holographic images and the changes occurring in them when attempting to unauthorized access to the objects they protect. The economic efficiency of the proposed invention is determined by an increase in the number of detected during control, including operational, operations to identify counterfeit and falsified products and registration and cases of unauthorized access (interference) to protected objects.EFFECT: problem solved in the proposed technical solution is to increase the reliability of the results of authenticity control and registration of the facts of unauthorized access to products (objects) protected by such labels and tapes.5 cl, 2 dwg

Description

The invention relates to security labels and adhesive control sealing and packaging tapes that allow visual control of their authenticity and reveal the facts of their re-sticking on protected products (objects). Visual control implies the possibility of operative visual and / or instrumental (using the simplest optical instruments such as magnifiers and lenses with magnification from four to ten times) determining the manufacturer, the integrity and the absence of re-sticking of protective labels and tapes. To fulfill these requirements, special holographic security elements are widely used, which have, easily distinguishable visually, optical protective effects [1,2]. These include widely used holographic and diffractive structures that form images that change when holograms are viewed from different angles of view. These are kinegrams, nanoscale diffractograms of DID, DIP, and DOID types of structures, holographic structures with “flip-flop” effects, etc. When these structures are rotated in space, the color, contrast and appearance of the images they form change. The complexity of manufacturing such elements practically excludes the possibility and expediency of their counterfeiting. On the other hand, their authenticity can be easily verified visually. To ensure the possibility of visual fixation of unauthorized access, interlayer adhesion layers of various degrees of stickiness are introduced into the multilayer structure of holographic elements (EP-A 1113059). Mechanical stresses arising in such holographic elements during unauthorized access attempts lead to the destruction of their optical layers, causing sharp, visually easily distinguishable, changes in the images they form.

Closest to the proposed invention are the labels and tapes described in patent RU 2576371, in the security elements of which multilayer holographic structures are used containing colored translucent layers in contact with adhesive adhesive layers of varying degrees of stickiness, which ensures the destruction of the formed holographic images when peeling off or re-gluing labels and tapes. However, the damage that occurs in the colored semitransparent layers turns out to be difficult to visualize (fuzzy and blurred) due to their observation, as indicated in the patent description, through a “semitransparent metal layer or a layer with a high refractive index”. The complexity of visual registration of the destruction of colored layers is also due to the fact that colored lacquer layers are formed on the basis of the introduction of “dyes and pigments” into them, which slightly change their color and brightness characteristics depending on the viewing angle. This complicates the visualization and registration of protective holographic effects, which are based precisely on the change in the formed holographic images when changing the viewing angles. In addition, observation and control of holographic images created by the relief in the embossed lacquer layer located above the introduced colored lacquer layers also turn out to be difficult to perform (protective holographic effects formed in the relief of the embossed layer become hardly distinguishable).

The task to be solved in the claimed invention was to eliminate these disadvantages. It is necessary to achieve greater clarity of the considered holographic images formed by the holographic relief of the embossed layer during authentication checks, and a clear visual distinction of changes in the holographic images that occur after unauthorized access to protected objects. It is possible to solve this problem if layered color-variable interference structures are used in the structure of the holographic element. Such structures, as a rule, are formed by vacuum deposition on thin transparent polymer films. They can be technologically integrated quite easily into films with embossed holographic reliefs and intermediate adhesive layers. Security holographic elements made from such films have the necessary security features and allow more reliable registration of the destruction of the holographic lacquer layer and built-in interference layers arising from attempts to separate the holographic element from the protected products.

When solving the problem formulated above, a technical result is provided, which consists in reducing the possibility of making valuable products while facilitating the verification of their authenticity, which in turn, accordingly, determines the significant economic efficiency of the solutions proposed in the application.

The technical result is achieved due to the fact that a holographic element for security labels, sealing and packaging tapes with an indicator of tampering, made in the form of a flexible thin-film structure containing a transparent substrate with a varnish holographic layer applied to it, and a multilayer polymer structure conjugated with the latter, made of transparent and translucent polymer layers with different thicknesses and different refractive indices, as well as possibly transparent adhesion layers of various thicknesses and degrees of stickiness, characterized in that the optically transparent and translucent layers of the multilayer polymer structure conjugated with the holographic varnish layer form a color-variable reflective interference element.

FIG. 1 shows the multilayer structure of the claimed holographic security element. It consists of a transparent polymer substrate (1), on the lower surface of which there is a transparent varnish holographic layer (2) with a holographic relief imprinted in it. Under it, in accordance with the proposed proposed technical solution under consideration, a multilayer color-variable structure (3) is placed, consisting of transparent and / or translucent dielectric or intermetallic layers (5-9), the number of layers can vary in accordance with technical requirements). These layers have different thicknesses and optical refractive indices. The thicknesses and refractive indices of the layers are selected so that when viewing the structure in reflected and / or transmitted light, the color of the plate changes depending on the viewing angle. Transparent and semitransparent metal and intermetallic thin-film films with thicknesses of the order of several units or tens of nanometers or transparent adhesive layers of medium tack with thicknesses of the order of 1 μm can also be used as interlayers between the layers of the color-variable structure (4). The lower surfaces of a transparent polymer substrate and a lacquer holographic layer (2) are often covered with transparent thin-film metal layers (3), made, for example, of chromium, copper, aluminum or cobalt with a thickness of the order of several tens of nanometers. These metal interlayers provide the necessary adhesion between the layers of the holographic element and the color-variable structure (4), which ensures a uniform and relatively strong, but usually not sufficiently rigid, connection of the mating layers. In addition, on the lower surface of the color-variable structure (4), to increase its brightness and contrast, a reflective opaque reflective metal layer (9) is applied, with a thickness of the order of several hundred nanometers. This can be, for example, reflective layers of aluminum or copper.

Transparent luminescent dyes can be introduced into the transparent holographic varnish layer (2) and transparent adhesive and adhesive connecting layers and interlayers. This can greatly facilitate the verification of the authenticity and facts of unauthorized access to labels and sealing tapes and, accordingly, to the products protected by them, especially in poor lighting during operational checks, for example, at night, which will naturally require the use of additional UV or IR illuminators.

The lower surface of the color-variable structure (3) is covered with an adhesive layer (10) of rigid fixation with a thickness of the order of several microns. Technologically, the holographic security element is placed on non-adhesive paper (11). The upper surface of the transparent substrate (1) of the security holographic element is covered with a transparent silicone coating (12), which allows storage, storage and transportation of security elements placed on the surface of non-adhesive paper (11) produced in rolls or sheets. The proposed structure of the holographic security element makes it possible to carry out its production in mass editions.

When protecting any product, one of the holographic elements is separated from the adhesive paper (11) and placed (glued) in certain places of the protected product using rigid fixation glue (10). When viewing the holographic element from the side of the transparent substrate, it is easy to control the integrity of the relief layer of the holographic element. At attempts to unauthorized access to the product (peeling off, re-sticking a protective label or a sealing holographic tape) containing the proposed holographic security element, its relief lacquer layer is destroyed and at the interfaces of the layers of the holographic element, made of materials not rigid fixation. Such damage is easily recorded by visual observation of the images formed by the proposed holographic security element. Thus, the proposed holographic security element solves the problem. It will make it possible to determine the authenticity of the holographic element, and, accordingly, the products protected by it, by clear and contrasting holographic images of the security element, not distorted by the introduction of additional thin-film structures, which is inherent in the above analogs. On the other hand, when attempting to unauthorized access, violations of the embossed holographic layer are more clearly and contrastingly visualized due to the introduction of a color-variable structure into the holographic security element (4).

In the manufacture of experimental samples of the proposed technical solution, one of the main requirements was to reduce their cost, which led to the use of the cheapest color-variable interference structures, with the least number of layers, therefore, as a rule, structures with 2 or 3 transparent or translucent layers were used. ...

Specific examples of the implementation of the proposed technical solution are given below.

Example 1

FIG. 2 shows the structure of a color-variable holographic security element or a fragment of a control sealing or packaging tape (adhesive tape).

On a transparent polymer (1) substrate (PET, polycarbonate, polypropylene, etc.) with a thickness of d = 1 5 μm, a semitransparent metal layer of chromium Cr (2), (or Al, Ag, Cu) with a thickness d = 5-10 nm, with an optical density of 0.4 - 0.5 OD. After that, it was applied by the method of gravure printing on the entire surface or selectively, according to a given design, a layer of “spacer” (3) - an optically transparent polymer with a refractive index of n = 1.5 - 1.8 and a thickness after drying h = 0 , 2 - 0.7 µm, depending on the required color transitions that occur when the direction of the viewing angle of the security element is changed. A reflective layer of aluminum (4) with a thickness of d = 0.5-1 microns and an optical density of 1.8-2.5 OD is deposited on a transparent polymer layer by thermal vacuum evaporation. After that, holographic embossing was carried out over the layer (4). Next, a layer of permanent stickiness of rigid fixation was applied to the embossed layer (5). The described multilayer structure was mated with a non-adhesive paper tape (6) and covered with an anti-adhesive silicone layer (7) with a thickness of about 1 μm.

Example 2

The structure and arrangement of the layers of the security element corresponded to that shown in Fig. 2. However, unlike the security element described in Example 1, the layer (3) of the transparent spacer was formed by thermal evaporation in vacuum e in the form of a layer of magnesium halide MgF ₂ with a refractive index n = 1.38 and a thickness d = 0.2 - 0.7 μm.

Example 3

The structure and arrangement of the layers of the security element corresponded to that shown in Fig. 2. But, unlike the protective elements described in Examples 1 and 2, instead of a semitransparent metal layer (2) and a transparent spacer layer (3), three-layer interference structures were used, formed by thermal evaporation in a vacuum: The first structure -

ZrO ₂ (d = 100 nm, n = 2.2) -Al ₂ O ₃ (d = 75 nm, n = 1.76) -ZrO ₂ (d = 100 nm, n = 2.2) The structure had a red yellow when the direction of observation is perpendicular to the plane of the structure and green-yellow when oblique.

The second structure is

ZrO ₂ (d = 75 nm, n = 2.2) -Si ₂ O ₃ (d = 300 nm, n = 1.76) -ZrO ₂ (d = 75 nm, n = 2.2) The structure had a golden color with the direction of observation perpendicular to the plane of the structure and blue-green - with an oblique angle of 45 degrees;

Films of other transparent materials (ZnS, MgF ₂ , SiO ₂ , TiO ₂ , Fe ₂ O ₃ , etc.) could also be used with an appropriate selection of their thicknesses and refractive indices.

In all the examples given, holographic embossed was performed from the side of the reflective aluminum layer (4).

The presented examples clearly demonstrate the possibility of using multilayer thin-film color-variable structures in holographic security elements for security labels and control sealing and packaging tapes.

Sources of information

1. V.M. Maresin Protected polygraphy, Directory 2012. -640 p.

2. V.V. Avdoshin Determination of the authenticity of banknotes. Methodological guide / 4-ed., 2017 - 21 pages.

Claims (5)

1. A holographic element for security labels, sealing and packaging tapes with an indicator of intrusion, made in the form of a flexible thin-film structure containing a transparent substrate with a holographic varnish layer applied to it and a multilayer structure conjugated to the latter of several colored varnish layers with different optical characteristics, as well as transparent adhesion layers of various thicknesses and degrees of stickiness, characterized in that the multilayer structure coupled with the lacquer holographic layer is a multilayer color-variable reflective interference element consisting of transparent and / or translucent layers. 2. The holographic element according to claim 1, characterized in that the multilayer color-variable reflective interference element is formed in the form of localized regions, randomly and / or regularly placed inside the holographic element. 3. The holographic element according to claim 1, characterized in that the structure of the multilayer color-variable reflective interference element includes interlayers of transparent adhesive adhesive interlayers separating its layers and having different degrees of stickiness (connecting ability). 4. The holographic element according to claim 1, characterized in that transparent luminescent dyes are introduced into the holographic varnish layer. 5. A holographic element according to claim 3, characterized in that the transparent adhesive adhesive layers contain transparent luminescent dyes.

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