CN-116887992-B - Security element and method for the production thereof

Abstract

The invention relates to a security element for value documents and the like, comprising a substrate (1, 21) which is coated with a heat-sealing adhesive (2, 22) which is non-tacky at room temperature and is suitable for coating the security element on a value document substrate, wherein the heat-sealing adhesive (2, 22) comprises a component which can be crosslinked by radiation and a reactive diluent.

Inventors

• W. Hofmiller
• C. Hertenkover
• E. Bahr
• P. Reyna

Assignees

• 捷德货币技术有限责任公司

Dates

Publication Date

20260505

Application Date

20220112

Priority Date

20210219

Claims (20)

1. 1. A security element for a document of value, the security element having a substrate (1, 21) coated with a heat-seal adhesive (2, 22) which is non-tacky at room temperature and suitable for coating the security element on a document of value substrate, Wherein the heat-seal adhesive (2, 22) comprises a component capable of radiation crosslinking and a reactive diluent, Wherein the reactive diluent is a low molecular weight compound having a molecular mass M < 1000g/mol, wherein the low molecular weight compound is selected from TMP (EO) x TA and DPHA, and Wherein the heat seal adhesive (2, 22) comprises from 5% to 25% of a reactive diluent.
2. 2. The security element according to claim 1, wherein the heat-seal adhesive (2, 22) additionally comprises a plasticizer.
3. 3. The security element of claim 2, wherein the plasticizer has a melting point in the range of 50 ℃ to 120 ℃.
4. 4. The security element according to claim 2, wherein the plasticizer is selected from the group consisting of triphenylphosphine, pentaerythritol tetrabenzoate, cyclohexyl and dimethyl gold benzoate, sucrose benzoate and mixtures of two or more of the foregoing elements.
5. 5. The security element according to claim 2, wherein the plasticizer is contained in the heat-seal adhesive (2, 22) in a weight proportion in the range of 1% to 30% in terms of solids.
6. 6. The security element according to any of claims 1 to 5, wherein a heat-seal adhesive (2, 22) which is non-tacky at room temperature and suitable for coating the security element on a value document substrate is present at least physically dry.
7. 7. The security element according to any of claims 1 to 5, wherein the substrate (1, 21) is a planar substrate (1, 21) having two opposite main surfaces, wherein at least one main surface of the substrate (1, 21) is at least partially provided with a heat-seal adhesive (2, 22) which is non-tacky at room temperature and suitable for coating the security element on a value document substrate.
8. 8. Security element according to any of claims 1 to 5, wherein a heat-seal adhesive (2, 22) which is non-tacky at room temperature and suitable for coating the security element on a value document substrate is obtainable by means of a coating solution, emulsion or dispersion.
9. 9. Security element according to claim 8, wherein a heat-seal adhesive (2, 22) which is non-tacky at room temperature and suitable for coating the security element on a value document substrate is obtainable by means of an aqueous coating dispersion.
10. 10. Security element according to claim 8, wherein a heat-seal adhesive (2, 22) which is non-tacky at room temperature and suitable for coating the security element on a value document substrate is obtainable by means of a coating of an organic solvent-based solution.
11. 11. The security element of claim 10 wherein the organic solvent has at least butyl acetate, propyl acetate, or ethyl acetate.
12. 12. The security element according to claim 10, wherein the heat-seal adhesive (2, 22) additionally has a prepolymer which is non-tacky after physical drying at room temperature, contains on average at least two reactive groups, and has a molecular weight of at least 600 g/Mol.
13. 13. The security element according to claim 9, wherein the dispersion is selected from the group consisting of aliphatic polyurethane dispersions, aromatic polyurethane dispersions, acrylates, anionic acrylate modified polyurethane dispersions, polyurethane-polyether acrylates and mixtures of two or more of the foregoing elements.
14. 14. The security element according to any one of claims 1 to 5, wherein the heat seal adhesive (2, 22) comprises a cationic radiation curable resin.
15. 15. The security element according to any one of claims 1 to 5, wherein the radiation crosslinkable component is crosslinkable by ultraviolet radiation or electron radiation.
16. 16. The security element according to any of claims 1 to 5, wherein the heat seal adhesive (2, 22) comprises a photoinitiator.
17. 17. The security element according to any of claims 1 to 5, wherein the substrate (1, 21) is a transparent plastic film.
18. 18. A value document comprising a security element according to any one of claims 1 to 17.
19. 19. A method for manufacturing a security element according to any of claims 1 to 17, comprising the step of applying a heat-seal adhesive (2, 22) onto a substrate (1, 21), which heat-seal adhesive is non-tacky at room temperature and suitable for applying the security element onto a value document substrate, wherein the heat-seal adhesive (2, 22) comprises a component capable of radiation crosslinking and a reactive diluent.
20. 20. A method for manufacturing a value document according to claim 18, comprising the step of providing a value document substrate with a security element according to any one of claims 1 to 17.

Description

Security element and method for the production thereof Technical Field The present invention relates to a security element for value documents and the like, which is coated with a heat-sealing adhesive which is non-tacky at room temperature and which is suitable for coating the security element on a value document substrate. The invention further relates to a method for producing such a security element. The invention further relates to a value document having such a security element and to a method for producing a value document provided with a security element. Background The value document, in particular the banknote, is often provided with a security element to protect it, which enables the authenticity of the value document to be checked, while at the same time serving as a protection against unauthorized copying. The documents of value in the sense of the present invention may in particular be banknotes, stocks, certificates, credit cards, bonds, certificates, vouchers, checks, high-value tickets, but also other paper sheets with a risk of forgery, such as passports and other documents of certificates, as well as product security elements, such as labels, seals, packages, etc. In the following, the term "value document" also encompasses the primary stage of the value document, in particular the security paper, which has not yet been circulated. It is known to secure documents of value, such as banknotes, with security elements in the form of security threads, security tapes or patches or labels. Nowadays, in almost all security papers and banknote papers, threads coated with heat-seal adhesives, in particular heat-seal lacquers, are inserted as security threads into the paper on the paper machine. The heat-seal lacquer is used here to fix the threads in the paper in an improved manner. Furthermore, in banknote paper, heat-seal lacquer is used to apply holograms and hologram strips. In the coating of security elements by means of heat-seal lacquers, at least one of the substrates to be joined is coated with a solvent-based crosslinker solution or aqueous solution or dispersion. After physical drying by means of heat, there is a surface that is non-tacky at room temperature. Under the effect of temperature, the substance capable of sealing melts and acts as an adhesive. It is known from EP 1 776,240 B1 to use a heat-sealing adhesive which is non-tacky at room temperature for applying a security element to a value document substrate by a heat-sealing process at elevated pressure and elevated temperature. In addition, the heat-seal adhesive contains components that can be crosslinked by high-energy radiation. The presence of the component crosslinkable by high-energy radiation in the heat-sealing adhesive enables crosslinking by radiation when the security element is applied to the document of value substrate. In this case, a system is formed which has a high melting point up to non-meltable, whereby high stability, in particular outstanding hot water resistance, is achieved. The hot water resistance can be determined, for example, by means of a washing machine. Suitable hot water tests are carried out in particular at 100℃per 30 minutes or 60℃per 1.5 hours. The heat-sealing adhesives known from EP 1 776 B1 can be applied to the security element to be applied in the form of a solution, emulsion or in the form of a dispersion. The radiation-crosslinkable coating applied in this form melts at low temperatures and penetrates into the value document substrate, which makes processing easier. The security element coated in this way, which has not yet been crosslinked, can ideally be stored for a long period of time without a change in the melting point. Thus, for example, a film equipped with a coating that is non-tacky at room temperature can be rolled up and stored for a longer period of time without a change in the melting point. When the heat-sealing adhesives known from EP 1 776 B1 are applied to the security element to be applied in the form of a solution, emulsion or in the form of a dispersion, physical drying is required, which is carried out, for example, by a slight increase in temperature to 80 ℃. In this way, solvents and/or water which may be present are discharged from the radiation-curable dispersion, solution or emulsion. Physical drying requires in some cases intense application of heat, so that in the case of highly reactive adhesive systems, an unexpected curing takes place. In the case of a reaction-inert adhesive system, too short a heat application time during the application of the security element provided with the heat-seal adhesive to the document of value substrate would lead to insufficient curing and thus to a lack of adhesion of the security element to the document of value substrate. Disclosure of Invention The object of the present invention is to provide a security element by means of which the disadvantages of the prior art are overcome. The above-mentioned technical problem i