EP3504066A1

EP3504066A1 - Security element, method for producing the same and document of value

Info

Publication number: EP3504066A1
Application number: EP17758797.9A
Authority: EP
Inventors: Johann Kecht; Axel SCHLOSSBAUER; Stephan Steinlein
Original assignee: Giesecke and Devrient Currency Technology GmbH
Current assignee: Giesecke and Devrient Currency Technology GmbH
Priority date: 2016-08-23
Filing date: 2017-08-22
Publication date: 2019-07-03
Anticipated expiration: 2037-08-22
Also published as: US20190168530A1; WO2018036652A1; ES2805951T3; HUE050144T2; DE102016010196A1; EP3504066B1; US10576773B2

Abstract

The invention relates to a security element for enhancing the security of documents of value, comprising a first polymer, which contains a feature substance and is at least partially surrounded by a second polymer, wherein the first polymer is a hydrophobic, water-insoluble polymer, which can be converted into a hydrophilic, water-soluble polymer if the pH is increased and the ambient temperature is increased for a treatment period of less than 60 minutes, preferably less than 30 minutes, and the second polymer is a hydrophilic, water-soluble polymer, wherein the increased pH is greater than 12, preferably greater than 10, and the increased ambient temperature is greater than 90°C, preferably greater than 60°C.

Description

Security element, method of making the same and value document

The invention relates to a security element for securing value documents, comprising a feature substance-containing first polymer which is at least partially surrounded by a second polymer, wherein the first polymer is a hydrophobic, water-insoluble polymer, which at elevated pH and at elevated ambient temperature at a treatment time of at least 30 minutes is convertible into a hydrophilic, water-soluble polymer, and the second polymer is a hydrophilic, water-soluble polymer. The invention furthermore relates to methods for producing the security element and to a security document having the security document.

Paper recycling processes, which for environmental reasons should ideally also be subject to worn-out or defective production documents, in particular banknotes, usually take place at elevated temperature and at elevated pH. Conventional security elements to secure value documents, such as mottled fibers or planchettes with feature properties such as UV luminescence, IR absorption or photochromism, however, are so stable that they are not destroyed under the conditions of paper recycling processes. Typically, the conventional security elements are only damaged and thus remain as visible, disturbing fragments in the paper pulp. Consequently, worn security documents, but also security elements containing security paper as a source material for the production of banknotes, for example, as a result of production errors (eg, incorrect paper thickness, cracks in the paper web, wrong concentration of security elements) does not meet the specification for further processing, not without security reasons Another conventional paper recycling process. The paper manufacturer incurred in this way high costs for disposal.

The invention has for its object to provide an improved security feature for securing value documents. In particular, it is desirable to provide a security element that has sufficient stability to water and moisture so that the security element will not be destroyed under papermaking conditions but at the same time be so unstable that the security element will be destroyed under the more harsh conditions of the paper recycling process. The invention is further based on the provision of manufacturing methods for such a security element and the provision of a security document provided with the value document.

These objects are achieved by the feature combinations defined in the independent claims. Preferred embodiments are subject of the dependent claims.

Summary of the invention

1. (First aspect of the invention) A security element for securing value documents, comprising a feature substance-containing first polymer which is at least partially surrounded by a second polymer, wherein the first polymer is a hydrophobic, water-insoluble polymer which is at elevated pH and at elevated ambient temperature at a treatment time of less than 60 minutes, preferably less than 30 minutes, is convertible into a hydrophilic, water-soluble polymer, and the second polymer is a hydrophilic, water-soluble polymer, wherein the increased pH greater than 12, preferably greater than 10, and the elevated ambient temperature is greater than 90 ° C, preferably greater than 60 ° C.

2. (Preferred embodiment) Security element according to paragraph 1, wherein the security element results in a mulch fiber or planchette when introduced into a moist pulp. Upon introduction, the water-soluble second polymer is dissolved

chette or mottled fiber visible.

3. (Preferred embodiment) A security element according to paragraph 1 or 2, wherein the feature substance has luminescent, magnetic or photochromic properties and is preferably an IR absorber or a UV-stimulable phosphor.

4. (Preferred embodiment) A security element according to any one of paragraphs 1 to 3, wherein the first polymer is convertible by saponification in a basic medium in a water-soluble polymer.

5. (Preferred embodiment) A security element according to paragraph 4, wherein the first polymer is polyvinyl acetate or a polyester and is preferably polyvinyl acetate.

6. (Preferred embodiment) A security element according to any one of paragraphs 1 to 5, wherein the second polymer is polyvinyl alcohol or a polyvinyl alcohol copolymer, in particular a polyvinylpyrrolidone-polyvinyl alcohol copolymer or a polyvinyl alcohol-polyethylene glycol Graf t copolymer, and is preferably polyvinyl alcohol. 7. (Preferred embodiment) A security element according to any one of paragraphs 1 to 6, wherein the feature substance is a core-shell particle, wherein the core and the shell are preferably based on two different polymers, the shell is more preferably attackable by the action of aqueous bases and the shell is particularly preferably based on a melamine-formaldehyde condensation polymer.

8. (Preferred embodiment) A security element according to any one of paragraphs 1 to 7, wherein the proportion of the first, hydrophobic, water-insoluble polymer in the security element is less than 10 wt .-%.

9. (Preferred embodiment) A security element according to any one of paragraphs 1 to 8, wherein the weight ratio of the feature substance based on the first, hydrophobic, water-insoluble polymer is at least 1: 1, preferably at least 9: 1.

10. (Preferred embodiment) A security element according to any one of paragraphs 1 to 9, wherein the first hydrophobic, water-insoluble polymer has a molecular weight in a range of 100,000 g / mol to 500,000 g / mol.

11. (Preferred embodiment) A security element according to any one of paragraphs 1 to 10, wherein the security element is obtainable by a method comprising

the step of introducing a feature substance into a first polymer by extrusion; and

the step of coating the first polymer thus obtained with a second polymer. 12. (Preferred embodiment) A security element according to any one of paragraphs 1 to 10, wherein the security element is obtainable by a method comprising

the step of providing a layer, in particular a film, based on a second polymer;

the step of applying a solution containing a feature substance and a first polymer to the layer based on a second polymer; and

the step of applying a further layer, in particular a film based on a second polymer, to the layer based on a second polymer provided with the solution of the feature substance and of the first polymer.

13. (Preferred Embodiment) A security element according to paragraph 12, wherein the layers are each films having a thickness in the range of 10 to 100 micrometers, preferably 15 to 60 micrometers.

14. (Second aspect of the invention) A method of producing a security element for securing value documents according to any one of paragraphs 1 to 10, comprising

the step of coating the first polymer thus obtained with a second polymer,

wherein the first polymer is a hydrophobic, water-insoluble polymer which is convertible to a hydrophilic, water-soluble polymer at elevated pH and / or at elevated ambient temperature, and the second polymer is a hydrophilic, water-soluble polymer. 15. (Third aspect of the invention) A method of producing a security element for securing value documents according to any one of paragraphs 1 to 10, comprising

the step of providing a layer, in particular a film, based on a second polymer;

the step of applying a further layer, in particular a film based on a second polymer, to the layer based on a second polymer provided with the solution of the feature substance and of the first polymer,

wherein the first polymer is a hydrophobic, water-insoluble polymer that is convertible to a hydrophilic, water-soluble polymer at elevated pH and / or elevated ambient temperature, and the second polymer is a hydrophilic, water-soluble polymer.

16. (Preferred Embodiment) The method of paragraph 15, wherein the step of applying a solution containing a feature substance and a first polymer to the layer based on a second polymer is carried out by printing a solvent-based varnish containing the feature substance and the first polymer, and the step of applying a further layer based on a second polymer after drying the printed paint takes place.

17. (Preferred Embodiment) Method according to paragraph 15 or 16, comprising the additional step of cutting the obtained layer structure into individual security elements. 18. (fourth aspect of the invention) value document, in particular banknote, comprising a security element according to one of the paragraphs 1 to 13.

19. (Preferred embodiment) Document of value according to paragraph 18, wherein the feature substance is an IR absorber or a UV-stimulable phosphor and the intensity of the IR absorption of the IR absorber or the intensity of the emission of the UV-stimulable phosphor after exposure the value document in a medium with a pH greater than 12, preferably greater than 10, and an ambient temperature greater than 90 ° C, preferably greater than 60 ° C, during a treatment time of less than 60 minutes, preferably less than 30 minutes, decreases by more than 50%, preferably by more than 90%.

Detailed Description of the Preferred Embodiments

Value documents within the scope of the invention are items such as banknotes, checks, shares, tokens, identity cards, passports, documents and other documents as well as labels. The value document substrate does not necessarily have to be a paper substrate, in particular it could be a plastic substrate or a substrate having both paper components and plastic components.

The present invention makes it possible to provide security elements, such as mottled fibers or planchettes, having feature properties such as UV luminescence, IR absorption or photochromism, which can be introduced into paper or applied to paper during papermaking and have sufficient stability to water and moisture so as not to be destroyed during papermaking. the. At the same time, the security elements according to the invention are so unstable that they are destroyed under the more drastic conditions of the paper recycling process, ie at elevated temperature and at elevated pH. For the paper manufacturer, therefore, high cost savings are possible, moreover, the present invention is particularly advantageous in view of the ecological point of view. With the aid of the security elements according to the invention, for example, defective security paper sheets, value documents afflicted with production defects or worn value documents can easily be subjected to a conventional paper recycling process because the security elements are completely destroyed in the recycling process. This is achieved in particular by a suitable combination of water-soluble polymers, for example polyvinyl alcohol (PVA), and water-insoluble, hydrolysis-unstable polymers, for example polyvinyl acetate (PVAc). It is preferred that the water-insoluble polymer is converted to the water-soluble polymer by saponification in the basic medium so that only one type of polymer is present. The water-soluble polymer is preferably polyvinyl alcohol. Polyvinyl alcohol is often a constituent of the paper pulp of documents of value because it is used, for example, in the gluing and therefore does not adversely affect the properties of the paper pulp obtained during recycling.

The security element is based in particular on a feature-containing first polymer which is completely or partially surrounded by a water-soluble second polymer. The water-soluble second polymer ensures the compatibility of the security element with the paper, because it is loosely dissolved on contact with the wet paper pulp or the paper web and promotes the solid installation of the security element in the pulp. The second polymer is preferably polyvinyl alcohol or its copolymers, for example polyvinylpyrrolidone-polyvinyl alcohol copolymers or polyvinyl alcohol-polyethylene glycol-graft copolymers. Although polyvinyl alcohol has the best properties for incorporation into pulp, other water-soluble polymers such as polyvinylpyrrolidone are also suitable.

The first polymer containing the feature substances is expediently sufficiently moisture-stable in order to withstand the incorporation into the paper pulp without being damaged.

According to a preferred embodiment, the first polymer is a hydrophobic, water-insoluble polymer, for example polyvinyl acetate or certain polyesters. The hydrophobic polymer, however, is characterized in that it can be converted to a hydrophilic polymer by increased pH and / or ambient temperature, e.g. by saponification of ester groups. For example, polyvinyl acetate can be gradually saponified to polyvinyl alcohol, which is then water-soluble. Furthermore, certain polyesters and other polymers can be cleaved by saponification or other reactions to smaller, lower molecular weight units, thereby destroying the polymer.

According to a preferred embodiment, the first, water-insoluble polymer converts in the recycling process so that it corresponds to the second (water-soluble) polymer type. The combination of polyvinyl alcohol (PVA) and polyvinyl acetate (PVAc) is particularly preferred because PVAc can easily be hydrolyzed to PVA and therefore no other polymers or polymer degradation products appear in the recycling process in addition to the harmless PVA.

Security elements according to the invention can be formed in different ways. For example, the feature substance can be introduced by extrusion into the first polymer and then coated with the second polymer. Alternatively, a solution containing the first polymer and the feature substance can be applied to the second polymer and then covered by another layer of the second polymer. The complete encapsulation of the first polymer by the second polymer is advantageous since otherwise sufficient and homogeneous incorporation into the paper substrate can not take place. For example, when non-both sides covered security elements are added to the pulp, they are not well installed if the randomly distributed security elements touch the paper with their hydrophobic side. When fully wrapped, both sides of the security element are hydrophilic, and always build well into the pulp even when randomly arranged.

According to a preferred embodiment, the security element is produced by printing or coating a PVA film with a solvent-based printing lacquer containing PVAc and the feature substance. Preferably, after the printing ink has dried, the printed film is laminated with a second PVA film so that no free PVAc surfaces exist. This facilitates the introduction of the later security element, since untreated PVAc, in contrast to PVA, does not have good compatibility with the paper pulp and thus incorporates poorly. The security Elements can then be obtained, for example, by cutting or punching out the laminated films.

The PVAc surface of the isolated security elements is preferably covered by more than 80%, particularly preferably more than 90%, by PVA.

Two examples of the production of inventive safety elements; another example of the production of security elements according to the invention;

FIG. 3 shows a further example of the production according to the invention

Security elements.

FIG. 1, Case A, shows an example of the production of security elements according to the invention. According to this preferred embodiment, the PVA film is printed over the entire surface, that is to say for the production of e.g. In the case of mottled fibers, the film may be cut into strips to obtain mottled fibers having the same dimensions of the strips.

However, it is not easy to produce particularly thin mottling fibers or other patterns that are difficult to obtain by cutting or punching. In this case, the following embodiment (see Figure 1, Case B) is more advantageous: FIG. 1, Case B, shows another example of the production of security elements according to the invention. According to this preferred embodiment, the PVA film is printed with a pattern which corresponds to the shape of the later security element. For example, a pattern may be printed out of thin strips, which at the end represent the mottling fibers, or other motifs, such as waves, circles or triangles. These can be easily cut out at an appropriate distance from each other. Since the PVA is largely dissolved when introduced into the paper pulp, only the PVAc motif defined by the printing process remains as a visible security element.

According to a preferred embodiment, when imprinting the pattern in two directions, an edge is left free (corresponding to FIG. 1, case B). This offers, for example, advantages / when multi-colored patterns or complex shapes have to be cut out, since then the cutting position relative to the pattern can be ensured.

FIG. 2, Case C, shows another example of the production of security elements according to the invention. According to this preferred embodiment, when imprinting the pattern, an edge is left in one direction only. For example, this offers advantages such as less material consumption if the printed pattern is designed to be cut through. FIG. 3, Case D, shows a further example of the production of security elements according to the invention. According to this preferred embodiment, lines or other patterns are printed with a skew angle relative to the cutting direction. This ensures that the pattern does not have to be aligned, or in other words, the pattern position is not on the cutting position has to be adjusted. For example, when cutting a film with an obliquely printed line pattern into several strips of the same width, the same length distribution of lines always occurs, even if the film is slightly offset in the cutting tool. An example of an obliquely printed line pattern is shown as Case D in FIG.

According to a further preferred embodiment, a sample spacing unsynchronized relative to the cutting width is selected, for example the distance between two printed lines is 1.01 times that

Cutting width. As a result, e.g. controlled distributions can be generated on random pattern distributions, or it can be prevented that, for example, all imprinted lines of the cutting tool are cut exactly in the middle, as could be the case for a match between pattern spacing and cutting width.

Typical conditions in paper recycling are elevated temperatures, such as more than 60 ° C, preferably more than 90 ° C, and an elevated pH, for example a pH greater than 8, preferably a pH greater than 10, more preferably a pH greater than 12 at the same time applied high shear forces. Typical treatment periods are z; B. a treatment duration of more than 30 min, preferably more than lh. In order to guarantee complete destruction of the security element under these conditions, special embodiments are advantageous. The term "complete destruction" is taken to mean that, when the paper pulp is used again, no larger components of the security element that are visible to the eye remain, but a homogeneous impression of the paper pulp is achieved. If, for example, a red-colored iron oxide-containing mica fiber is used as the magnetic security element, the term "complete destruction" means that the iron oxide-containing polymer has essentially completely dissolved and no mottled fiber fragments or the like are more recognizable will still be present and homogeneously distributed in the paper pulp, but as there are usually only very small amounts of security elements relative to the pulp, they will no longer be perceived in a homogeneous distribution, only in places where the feature substance is in a higher concentration, such as In the polymer of the original security element, an increased and thus disturbing after recycling visibility is given.

In certain cases, it may nevertheless be advantageous to use feature substances which weaken or decompose in their perceptibility during the recycling process. This ensures that the recycled paper is e.g. even in a forensic analysis mithilfe e of a microscope or other aids is not or hardly distinguishable from "fresh" paper.

According to a preferred embodiment, the intensity of the feature substance used (for example the intensity of the emission of a UV-stimulable phosphor, or the intensity of the IR absorption of an IR absorber) during treatment in paper recycling decreases by more than 50%, preferably by more than 90%.

It is pointed out that in conventional, non-recyclable safety elements the feature substance is absorbed by the surrounding substrate. is protected and thus is not attacked even in the recycling process, even if the feature substance should actually be unstable in the process conditions. The use of resolving security elements is thus inherently necessary to achieve the desired effect.

According to a particularly preferred embodiment, the feature substance used is a core-shell particle. Preferably, the core-shell particle is based on two different polymers. More preferably, the polymer of the shell is accessible by the action of bases. Preferably, the type and thickness of the shell is chosen so that the feature substance on the one hand meets the necessary criteria for stability of base, which are necessary for use in documents of value, on the other hand, largely destroyed in the harder conditions of paper recycling. The shell is preferably a layer of melamine-formaldehyde condensation polymer. Although melamine-formaldehyde

Condensation polymers are usually chemically very stable, the stability of the shell can be controlled very well on the thickness thereof, so that here a controlled adjustment of instability against hot aqueous bases is possible.

To ensure complete hydrolysis of the security feature, additional framework conditions are necessary. In particular, when using water-insoluble polymers which still have to be decomposed or converted, not arbitrarily large amounts can be used, since the hydrolysis otherwise causes too much time and is not completed within the usual paper recycling step. In a preferred embodiment, less than 10 weight percent of the security element is based on the water-insoluble polymer, more preferably less than 1 weight percent.

In a further preferred embodiment, the weight ratio of the feature substance used (for example the luminescent pigment used) relative to the water-insoluble polymer surrounding the feature substance is in particular at least 99: 1, preferably at least 9: 1, particularly preferably at least 1: 1.

Furthermore, the chain length of the used, surrounding the feature substance first polymer has an impact on the rate of hydrolysis, but also on the processability of the laminated film composite.

In a preferred embodiment, therefore, the first polymer in particular has a molecular weight of less than 100,000 g / mol. Here, the hydrolysis rate is particularly high.

In a further preferred embodiment, the first polymer has a molecular weight of more than 500,000 g / mol. Here, the workability is particularly good.

In a further preferred embodiment, the first polymer has a molecular weight in a range of 100,000 g / mol to 500,000 g / mol. In this case, a sufficient hydrolysis rate and a good processability are combined. For most applications, this third embodiment is technically advantageous, and therefore particularly preferred over the other two embodiments. In a preferred embodiment, the PVA film has a thickness in the range of 10 to ΙΟΟμητ, more preferably in a range of 15 to 60μπι.

In a preferred embodiment, the PVA film is a so-called hot water-soluble PVA, which is a PVA which, in contrast to the so-called cold-water-soluble PVA, does not react at elevated temperature, e.g. above 60 ° C, completely dissolves. This makes it possible to adjust the security elements so that they can be introduced into the paper web by direct addition into the water of the paper machine, and the PVA only dissolves completely in the later drying process by heating the paper web.

In a preferred embodiment, the security elements are introduced into the water of the paper machine.

In a further preferred embodiment, the security elements are scattered on the moist paper web, for example by using a vibrating trough.

In a preferred embodiment, the coating or printing of the PVA film uses a mixture based on the feature substance and a solution of polyvinyl acetate in an organic solvent. Preferably, the organic solvent is ethyl acetate or acetone. There may be other ingredients or solvents to improve the printing properties of the printing ink, such as viscosity and wettability. In a preferred embodiment, the recyclable security elements described herein are combined with other, non-recyclable security elements or designed so that they are only partially recyclable. For example, in accordance with the invention, green mottled fibers according to the invention can be mixed with non-inventive red mottled fibers. Alternatively, in the preparation of the security elements, first (eg green) lines based on a hydrolyzable polymer can be printed and second (eg red) lines can be printed on the basis of a hydrolysis-stable printing ink. In this way, it is also possible to construct parts of a safety element from hydrolyzable or hydrolysis-stable constituents. For example, in the case of a printed flag with three national colors, two national colors can be hydrolyzed and one country color can be made resistant to hydrolysis. If paper or a document of value is recycled with a corresponding mixture of recyclable and non-recyclable security elements, the non-recyclable security elements remain in the paper pulp, or the security elements are partly discolored or discolored. In this way it can be tracked, for example, if the paper mass is recycled material. This is advantageous, for example, to detect plagiarism based on stolen Papierfabrik- Committee, or on the basis of recycled pulp from shredded banknotes.

The invention will be described below with reference to preferred exemplary embodiments.

Embodiment 1: blue luminescent mottled fibers A P VA film having a thickness of 25 μm is coated with a solution of 1% by weight of polyvinyl acetate having a molecular weight of 140,000 g / mol, which contains 10% by weight of a UV-activatable blue-luminescent security pigment based on core-shell particles. The solvent used is ethyl acetate. The coating has a basis weight of 5 grams per square meter. After evaporation of the ethyl acetate, the applied layer is covered with a second PVA film having a thickness of 25 microns and laminated by passing a hot metal roller. The laminated film composite is subsequently cut into mottled fibers of the size 5 mm × 1 mm and introduced into the paper stock during papermaking.

This gives a paper with recognizable under blue light as blue stripes mottled fibers.

The paper is then recycled (at high shear, at 80 ° C, at a pH of 11, treatment time: 1 hour). From the resulting pulp a new paper is produced. Under UV light no mottled fibers or other abnormalities are more visible.

Comparative Example 1: Blue Luminescent Melierfasern

A polyamide fiber having the same security pigment as in Embodiment 1 is produced. Polyamide fibers are widely used as mottling fibers for banknotes, their preparation is well known. However, they are non-recyclable fibers. As in embodiment 1, a paper with mottled fibers recognizable as blue stripes under UV light is obtained.

The paper is then recycled (high shear, 80 ° C, pH 11, 1 hour). From the resulting pulp a new paper is produced.

Under UV light, whole mottled fibers and their fractions, i. damaged or kinked mottled fibers visible in the paper.

Embodiment 2: green luminescent mottled fibers

A PVA film with a thickness of 30 μιη is printed with a pattern of 5 mm long and 200 μπι thick strip. The printing ink used is a mixture of acetone and 2 percent by weight of polyvinyl acetate of molecular weight 200,000 g / mol, which contains 5 percent by weight of a UV-activatable, green luminescent security pigment based on core-shell particles.

The pressure is 5 grams per square meter. After the proof has been dried, it is covered with a second PVA film having a thickness of 30 μm and laminated by passing a hot metal roller. The laminated film composite is then cut into pieces, each piece containing a strip of the printed stripe pattern, and incorporated into the paper stock during papermaking.

This gives a paper with librar fi bre pattern recognizable as green stripes under UV light. The paper is then recycled (high shear, 80 ° C, pH 11, 1 hour). From the resulting pulp a new paper is produced. Under UV light no mottled fibers or other abnormalities are more visible.

Exemplary Embodiment 3 IR Absorber Planchettes

A PVA film having a thickness of 50 μm is coated with a solution of 1% by weight of polyvinyl acetate having a molecular weight of 140,000 g / mol, which contains 10% by weight of an IR absorber pigment based on core-shell particles. The solvent used is ethyl acetate. The coating has a basis weight of 5 grams per square meter. After evaporation of the ethyl acetate, the applied layer is covered with a second PVA film having a thickness of 50 microns and laminated by passing a hot metal roller. The laminated film composite is subsequently cut into planchettes of the size 5 mm × 5 mm and introduced into the pulp during papermaking.

A paper is obtained which, when viewed with suitable equipment, e.g. with an IR sensor for bank notes, corresponding points with IR absorption shows.

The paper is then recycled (high shear, 80 ° C, pH 11, 1 hour). From the resulting pulp a new paper is produced. Upon re-viewing, no sites with IR absorption or other abnormalities are more visible. Embodiment 4: red luminescent forms

A PVA film having a thickness of 25 μm is printed with a solution of 1% by weight of polyvinyl acetate having a molecular weight of 140,000 g / mol, which contains 10% by weight of a UV-activatable, red-luminescent security pigment based on core-shell particles , The solvent used is ethyl acetate. The print pattern is based on a variety of objects in the form of small fish with a size of about 2 mm x 4 mm. The pressure strength has a basis weight of 5 grams per square meter. After evaporation of the ethyl acetate, the pressure is covered with a second PVA film having a thickness of 25μηα and laminated by passing a hot metal roller. The laminated film composite is then cut into pieces, each piece containing one of the fish-like objects, and placed in the pulp during papermaking.

This gives a paper with under UV light as small red fish recognizable objects. The paper is then recycled (high shear, 80 ° C, pH 11, 1 hour). From the resulting pulp a new paper is produced. Under UV light, no luminescent objects or other abnormalities are more visible.

Embodiment 5: partially recyclable planchettes

A PVA film with a thickness of 40 μπχ is printed with a tricolor pattern of UV luminescent colors, such as a national flag the size 6 mm x 4 mm, which contains the colors blue, white and red. The individual flags of the country are 10 mm apart on all sides so that they can be easily separated by cutting the film. The blue and white portions of the pattern are printed with a pressure varnish consisting of a combination of luminescent pigment, ethyl acetate and polyvinyl acetate and then dried. The blue and white parts dissolve in the recycling process. The red portions of the pattern are printed with a UV-curable printing ink containing the luminescent pigment and cured by UV irradiation. UV-curable printing inks are often used for printing value documents and generally show a very high stability to water and aqueous solutions. The red components are stable compared to the recycling process and thus remain unchanged.

If such planchets are introduced into paper pulp during papermaking, a security paper is obtained which shows multicolored country flags under UV light. The paper may also contain other (e.g., forensic) features or have special properties, e.g. haptic properties or optical properties. When such a paper or remnants are recycled from value documents made therefrom, e.g. In order to produce counterfeits, clearly visible red portions of the original multicolored pattern remain in the recy- cled paper. The paper can thus be clearly identified as recycled material of the original security paper, even if the other characteristics (other characteristics, haptic and optical characteristics) are the same as those of the original security paper.

Claims

P atentan pr oce

A security element for securing value documents, comprising a feature-containing first polymer which is at least partially surrounded by a second polymer, wherein the first polymer is a hydrophobic, water-insoluble polymer which at elevated pH and at elevated ambient temperature at a treatment time of less than 60 minutes, preferably less than 30 minutes, is convertible to a hydrophilic, water-soluble polymer, and the second polymer is a hydrophilic, water-soluble polymer, wherein the elevated pH is greater than 12, preferably greater than 10; increased ambient temperature greater than 90 ° C, preferably greater than 60 ° C, is.

2. Security element according to claim 1, wherein the security element results in a mulch fiber or planchette when introduced into a wet paper pulp.

3. The security element according to claim 1, wherein the feature substance has luminescent, magnetic or photochromic properties and is preferably an IR absorber or a UV-activatable phosphor.

4. A security element according to any one of claims 1 to 3, wherein the first polymer is convertible by saponification in a basic medium in a water-soluble polymer.

5. The security element according to claim 4, wherein the first polymer is polyvinyl acetate or a polyester and is preferably polyvinyl acetate.

6. The security element according to claim 1, wherein the second polymer is polyvinyl alcohol or a polyvinyl alcohol copolymer, in particular a polyvinylpyrrolidone-polyvinyl alcohol copolymer or a polyvinyl alcohol-polyethylene glycol graft copolymer, and is preferably polyvinyl alcohol.

7. The security element according to claim 1, wherein the feature substance is a core-shell particle, wherein the core and the shell are preferably based on two different polymers, the shell is more preferably attackable by the action of aqueous bases, and Shell particularly preferably based on a melamine-formaldehyde condensation polymer.

8. The security element according to any one of claims 1 to 7, wherein the proportion of the first, hydrophobic, water-insoluble polymer in the security element is less than 10 wt .-%.

9. A security element according to any one of claims 1 to 8, wherein the weight ratio of the feature substance based on the first, hydrophobic, water-insoluble polymer is at least 1: 1, preferably at least 9: 1.

10. A security element according to any one of claims 1 to 9, wherein the first, hydrophobic, water-insoluble polymer has a molecular weight in a range of 100,000 g / mol to 500,000 g / mol.

11. A security element according to any one of claims 1 to 10, wherein the security element is obtainable by a method comprising

the step of introducing a feature substance into a first polymer by extrusion; and the step of coating the first polymer thus obtained with a second polymer.

12. A security element according to any one of claims 1 to 10, wherein the security element is obtainable by a method comprising

the step of providing a layer, in particular a film, based on a second polymer;

13. The security element of claim 12, wherein the layers are each films having a thickness in the range of 10 to 100 micrometers, preferably 15 to 60 micrometers.

14. A method for producing a security element for securing value documents according to one of claims 1 to 10, comprising

the step of coating the first polymer thus obtained with a second polymer,

15. A method for producing a security element for securing value documents according to one of claims 1 to 10, comprising

the step of providing a layer, in particular a film, based on a second polymer;

16. The method of claim 15, wherein the step of applying a solution containing a feature substance and a first polymer to the layer based on a second polymer is by printing a solvent-based varnish containing the feature substance and the first polymer, and the Step of applying a further layer based on a second polymer after drying the printed paint is carried out.

17. The method of claim 15 or 16, comprising the additional step of cutting the obtained layer structure into individual security elements.

18. value document, in particular banknote, comprising a security element according to one of claims 1 to 13.

19. The document of value according to claim 18, wherein the feature substance is an IR absorber or a UV-stimulable phosphor and the intensity of the IR absorption of the IR absorber or the intensity of the emission of the UV-stimulable phosphor after exposure of the value document in one Medium with a pH greater than 12, preferably greater than 10, and an ambient temperature greater than 90 ° C, preferably greater than 60 ° C, during a treatment time of less than 60 minutes, preferably less than 30 minutes, by more than 50 %, preferably decreases by more than 90%.