Anti-counterfeiting base material, anti-counterfeiting paper and manufacturing method

Abstract

The invention relates to a security substrate for producing security and value documents, comprising a fibrous substrate body (22) which comprises, by mass, 40% to 96%, based on the dry weight of the fibrous substrate body, fibers, in particular cellulose fibers, 1% to 20%, based on the dry weight of the fibers, of at least one anionic polymer, in particular a carboxylated polymer, said anionic polymer having a glass transition temperature Tg of above-40 DEG C, and 0.5% to 5% by dry weight, based on the dry weight of the fiber, of at least one cationic precipitating agent, the anionic polymer being present on the surface of the fiber in the form of a precipitate, according to the invention, the anionic polymer is preferably an anionic polymer, in particular a carboxylated polymer, having a glass transition temperature Tg of above-40 DEG C; the fibrous substrate body (22) is provided with an antifouling layer (24, 26; 62).

Description

FIELD OF THE INVENTION

[0001] The present invention relates to a security substrate for manufacturing security and valuable documents, a security paper having such a security substrate, and a method for manufacturing such a security substrate. BACKGROUND OF THE INVENTION

[0002] Banknotes and other valuable documents are made of security substrates, which are usually composed of paper or have a paper core and have special security features, such as at least partially embedded security threads or watermarks.

[0003] The circulation time of known banknotes depends to a large extent on the degree of wear of the banknotes. Here, early contamination is considered to be one of the main reasons for the limited circulation time of banknotes. Since banknote paper is very porous, it has a relatively large surface area and high surface roughness. Although the size of the resulting protrusions and cavities is on the order of magnitude lower than the resolution limit of the human eye, they are still the starting points for dirt deposition compared to a smooth surface.

[0004] In the patent document WO 2021 / 023601 A1, an anti-wrinkle and anti-stain fiber substrate obtained by a wet method is proposed, which has high mechanical strength to prevent banknotes made of the fiber substrate from being exposed to an excessive degree of microbial load during aging in circulation.

[0005] Based on this, the technical problem to be solved by the present invention is to further improve the circulation duration of known security substrates. Here, the typical characteristics of banknotes, such as sound, color, handleability, and transmission characteristics, are ideally maintained.

[0006] The above technical problem is solved by the features of the independent claims. The improved designs of the present invention are the technical solutions of the dependent claims.

[0007] According to the present invention, a security substrate for manufacturing security and valuable documents comprises a fibrous substrate body, which by mass comprises:

[0008] – 40% to 96% by dry weight of fibers, in particular cellulose fibers, based on the dry weight of the fibrous substrate body,

[0009] - 1% to 20% by dry weight of at least one anionic polymer, in particular a carboxylated polymer, based on the dry weight of the fibers, the glass transition temperature T g of which is above -40 °C, and

[0010] - 0.5% to 5% by dry weight of at least one cationic precipitant, based on the dry weight of the fibers,

[0011] wherein the anionic polymer is present in the form of a precipitate on the surface of the fibers.

[0012] As a feature, the fibrous substrate body is provided with an anti-fouling layer on at least one of its main surfaces.

[0013] In the patent document WO 2021 / 023601 A1, it is proposed to use a fibrous substrate body of this type as a fibrous substrate. The inventors have found that although the known fibrous substrate body has a high z-strength measured according to the Scott Bond method, its circulation stability can be unexpectedly further improved by an additional anti-fouling layer.

[0014] In a first advantageous design, the fibrous substrate body is respectively provided with anti-fouling films on its opposite main surfaces, and the two anti-fouling films together form a composite anti-counterfeiting substrate.

[0015] According to a second advantageous design, the fibrous substrate body is provided with an anti-fouling coating on at least one of its main surfaces. The fibrous substrate body can also be provided with anti-fouling coatings on its two opposite main surfaces to achieve particularly high circulation stability.

[0016] In an advantageous variant of the present invention, the anti-fouling coating consists of a composition comprising an acrylate system as the sole binder and no filler material. The composition is preferably present on the fibrous substrate at a unit area weight of 1 to 6 g / m 2 , in particular 2 to 3 g / m 2 . The anti-fouling coating can in particular consist of the composition described in the patent document WO 00 / 00697 A1, the disclosure of which in this regard is incorporated into the present application.

[0017] Advantageous designs of the composition are described in WO 00 / 00697 A1. For example, the composition can in particular include an acrylate or a mixture consisting of a polymer or copolymer having a high acrylate content as the binder. The composition can also include at least one material at a low concentration, which has properties that can be visually and / or machine-detected for anti-counterfeiting features and / or coding. The material advantageously includes properties of luminescence, magnetism, conductivity, light diffraction, light interference or light polarization, and the material can also be partially provided, preferably in the form of a pattern in the coating.

[0018] According to another equally advantageous variant of the present invention, the anti-fouling coating is formed based on polyurethane.

[0019] In this case, the antifouling coating can advantageously consist of a composition comprising 50% to 70% by dry weight of a transparent or translucent binder, 30% to 50% of silica, and, if necessary, at least one functional additive, where the sum of these components constitutes 100% of the composition, and where the elastomeric binder is selected from the group consisting of polyurethanes that can be used in the form of a stable aqueous dispersion. Further details and advantageous embodiments of such a composition can be derived from WO 2002 / 020902 A1, the disclosure of which in this regard is incorporated into the present application.

[0020] The antifouling coating based on polyurethane can also consist of a composition comprising a non-colored polyurethane and, if necessary, at least one functional additive. Other details and advantageous embodiments of such a composition can be found in the patent document WO 96 / 28610 A1, the disclosure of which in this regard is incorporated into the present application.

[0021] In all variants of the present invention, the antifouling coating advantageously includes a biocidal additive as a functional additive, in particular a fungicidal, bactericidal, and / or virucidal additive. In particular, quaternary ammonium salt compounds, diiodomethyl p-tolyl sulfone, 3-iodo-2-propynyl butylcarbamate (IPBC), and thiabendazole can be used as biocidal additives. These and other biocidal additives that can be advantageously applied are described in the patent document WO 2022 / 189043 A1, the disclosure of which in this regard is incorporated into the present application. Singlet oxygen catalysts can also be advantageously used as biocidal additives.

[0022] According to an advantageous expansion design of the present invention, the antifouling coating includes a characteristic material that can be visually and / or machine-inspected as a functional additive. In particular, luminescent, infrared-absorbing, and / or magnetic characteristic materials can be used.

[0023] In addition, the fiber substrate body itself can also have a biocidal configuration and includes, for example, 0.001% to 1% by dry weight of at least one biocide. To enhance the effect, the biocidal configuration of the fiber substrate body itself can be combined with the biocidal configuration of the above-mentioned antifouling coating of the fiber substrate body.

[0024] The anionic polymer of the fiber substrate body is advantageously selected from carboxylated styrene-butadiene copolymers.

[0025] The fibrous substrate body is advantageously formed to be similar to the fibrous substrate in patent document WO 2021 / 023601 A1, the disclosure of which is incorporated herein by reference in its entirety. This applies in particular to the advantageous design of the anionic polymer, cationic precipitant and fibers of the fibrous substrate body described in WO 2021 / 023601 A1. As described in more detail in WO 2021 / 023601 A1, biocides, wetting agents and fillers may also be present in the fibrous substrate body.

[0026] According to an advantageous expansion design of the present invention, a partial or full internal printing layer is provided between the fibrous substrate body and at least one antifouling layer. The internal printing layer can be, for example, an offset printing layer, a gravure printing layer or a screen printing layer. The anti-counterfeiting substrate then constitutes a pre-printed anti-counterfeiting substrate, and its internal printing layer is well protected by the antifouling layer.

[0027] The present invention also includes an anti-counterfeiting paper having an anti-counterfeiting substrate of the above type and at least one partial or full external printing layer applied to the antifouling layer. The external printing layer can also particularly be an offset printing layer, a gravure printing layer or a screen printing layer. Also to prevent dirt from accumulating on the external printing layer, the external printing layer can be covered by other layers, such as a paint layer or other antifouling layer. The other antifouling layer can particularly be a film or coating of the above type here. Therefore, the term "external printing layer" only refers to the printing layer being outside the antifouling layer on the fibrous substrate, and does not mean that such a printing layer constitutes the outermost layer of the anti-counterfeiting paper.

[0028] The anti-counterfeiting paper can particularly form banknotes or other valuable documents.

[0029] Finally, the present invention also includes a method for manufacturing an anti-counterfeiting substrate of the above type. Here, a fibrous substrate body having the above composition is first provided. The fibrous substrate body can advantageously be manufactured according to one of the methods described in WO 2021 / 023601 A1.

[0030] In a first method variant, an antifouling coating is applied to one or both main surfaces of the fibrous substrate body. The antifouling coating is preferably applied or printed at a unit area weight of 1 g / m 2 to 6 g / m 2 , especially 2 g / m 2 to 3 g / m 2 . Before applying the antifouling coating, a printing layer can be applied to the fibrous substrate to form an internal printing layer in the anti-counterfeiting substrate. After applying the antifouling coating, the anti-counterfeiting substrate can still be reprocessed, for example by calendering to improve the smoothness of the surface.

[0031] In another method variant, the fibrous substrate body is provided with anti-fouling films on both sides respectively, so as to jointly form a composite anti-counterfeiting substrate with the fibrous substrate. For this purpose, the fibrous substrate body can be laminated with two films, for example.

[0032] The following explains other embodiments and advantages of the present invention according to the accompanying drawings, in which, for the sake of clarity, the presentation of true dimensions and proportions is abandoned. Brief Description of the Drawings

[0033] In the drawings:

[0034] Figure 1 A schematic diagram of a banknote having an anti-counterfeiting substrate according to the present invention is shown,

[0035] Figure 2 and 3 An anti-counterfeiting substrate according to an embodiment of the present invention is respectively shown,

[0036] Figure 4 It shows the use of Figure 3 The printed anti-counterfeiting paper manufactured with the anti-counterfeiting substrate in

[0037] Figure 5 An anti-counterfeiting substrate according to another embodiment of the present invention is shown,

[0038] Figure 6 It shows the use of Figure 5 The printed anti-counterfeiting paper manufactured with the anti-counterfeiting substrate in

[0039] Figure 7 An anti-counterfeiting substrate with an anti-fouling film according to another embodiment of the present invention is shown. Detailed Description of the Invention

[0040] The present invention is described below by taking an anti-counterfeiting substrate for banknotes as an example. For this purpose, Figure 1 A schematic diagram of a banknote 10 is shown. The banknote 10 has an anti-counterfeiting substrate 12, and the anti-counterfeiting substrate 12 is equipped with printing elements 14, 16, a portrait watermark 18 and other anti-counterfeiting features not shown in the figure if necessary.

[0041] Figure 2 An embodiment of the anti-counterfeiting substrate 20 used in manufacturing the banknote 10 is shown. The anti-counterfeiting substrate 20 includes a fibrous substrate body 22 and an anti-fouling coating 24 applied on the fibrous substrate body 22.

[0042] The fibrous substrate body 22 is formed in the manner described in detail above. In Figure 2In an embodiment, with reference to the dry weight of the fibrous substrate body, the fibrous substrate body 22 specifically comprises fibers having a mass of 60% to 96%, preferably even 70% to 96% of the dry weight, in particular cellulose fibers. The fibrous substrate body further comprises 1% to 10%, preferably 3% to 8% of the dry weight of a carboxylated styrene-butadiene copolymer, which preferably has a glass transition temperature of -30°C to -20°C, particularly preferably -25°C, and at least one cationic precipitant, preferably a polyamide-polyamine epichlorohydrin resin, based on the dry weight of the fibers, in an amount of 0.8% to 3.5% of the dry weight.

[0043] The fibrous substrate body 22 has a particularly high z-strength or tear resistance, which can be determined, for example, according to the Scott Bond method.

[0044] The antifouling coating 24 applied to the fibrous body consists of a composition that includes an acrylate system as the sole binder and does not contain a filler material. In this embodiment, the coating 24 is applied or printed over the entire surface of the fibrous substrate body 22, wherein the areal weight of the coating is between 1 and 6 g / m 2 and is particularly 2 - 3 g / m 2 .

[0045] Since the antifouling coating 24 does not contain a filler material, the composition wets the fibers in the surface area of the fibrous substrate body 22 and forms a closed surface film that minimizes the opportunity for dirt to come into contact with the fibers. The antifouling coating 24 provides a smooth surface, reducing the likelihood of dirt accumulation. At the same time, the layer thickness of the coating 24 is so low that the common and desired properties of the fibrous substrate body 22, such as its grip and printability, are not impaired. The transmission properties of the fibrous substrate body are also retained, such that the perceptibility of watermarks, such as Figure 1 the portrait watermark 18 in

[0046] is not affected by the antifouling configuration. Figure 3 As shown by the security substrate 25 in

[0047] Figure 2 and 3 the security substrates 20, 25 in

[0048] have a high z-strength by using the fibrous substrate body and particularly high circulation stability due to the antifouling coating. In addition, the coatings 24, 26 provide an ideal printing surface for high printing resolution and good print pigment adhesion. Nevertheless, the typical properties of the fibrous substrate body 22, such as color, sound, grip, and transmission properties, are still retained.The antifouling coating 24 advantageously includes biocidal additives, in particular fungicidal, bactericidal and / or virucidal additives as functional additives. For this purpose, the antifouling coating 24 can include, for example, benzalkonium halides and compounds selected from didecyldimethylammonium halide, 3-iodo-2-propynyl butylcarbamate, diiodomethyl p-tolylsulfone and thiabendazole.

[0049] Figure 4 Exemplarily shown is the use Figure 3 of the anti-counterfeiting base material 25 in Figure 1 to produce the printed anti-counterfeiting paper 30. Here, for example, the front printing section 34 and the back printing section 36 are respectively applied to the antifouling coatings 24, 26 by offset printing, intaglio printing or screen printing. The printed anti-counterfeiting paper 30 can in particular be banknotes, such as

[0050] In an extended design of the present invention, as Figure 5 shown, in the anti-counterfeiting base material 40, a partial or full internal printing layer 42 is provided between the fibrous base material body 22 and one of the antifouling coatings 24. It should be understood that such an internal printing layer can also be provided on both sides of the anti-counterfeiting base material 40 between the fibrous base material body 22 and the corresponding antifouling coatings 24, 26. As Figure 2 shown, the antifouling coating can also be provided only on one of the two main surfaces of the fibrous base material body 22.

[0051] Reference Figure 6 , according to Figure 5 the pre-printed anti-counterfeiting base material 40 can be equipped with additional external printing layers, such as the front printing section and / or the back printing section 34, 36, applied to the antifouling coatings 24, 26, to obtain the printed anti-counterfeiting paper 50. The internal printing layer 42 can thus, for example, provide a background printing common to the entire series of banknotes, while the front and back printing sections 34, 36 form separate designs for different denominations.

[0052] Figure 7 Shown is an anti-counterfeiting base material 60 according to another embodiment of the present invention, in which a fibrous base material body 22 of the above type is respectively provided with antifouling films 62 on its opposite main surfaces, and together with the two antifouling films forms a composite anti-counterfeiting base material.

[0053] When further processed into anti-counterfeiting paper, the front printing section or the back printing section can be respectively applied to the antifouling film 62 as generally described above in connection with Figure 4 and 6 . In addition, a partial or full printing layer can be provided between the fibrous base material body 22 and one or both of the antifouling films 62 to obtain a partially pre-printed anti-counterfeiting base material.

[0054] The anti-fouling film 62 may be provided with a biocidal arrangement based on, for example, a quaternary ammonium salt compound.

[0055] Reference numeral

[0056] 10 Banknote

[0057] 12 Anti-counterfeiting substrate

[0058] 14, 16 Printing element

[0059] 18 Portrait watermark

[0060] 20, 25 Anti-counterfeiting substrate

[0061] 22 Fiber substrate body

[0062] 24, 26 Anti-fouling coating

[0063] 30 Printed anti-counterfeiting paper

[0064] 34 Front printing part

[0065] 36 Back printing part

[0066] 40 Anti-counterfeiting substrate

[0067] 42 Inner printing layer

[0068] 50 Printed anti-counterfeiting paper

[0069] 60 Anti-counterfeiting substrate

[0070] 62 Anti-fouling film

Claims

1. An anti-counterfeiting substrate for manufacturing anti-counterfeiting and valuable documents, the anti-counterfeiting substrate having a fibrous substrate body, the fibrous substrate body comprising, by mass: - 40% to 96% dry weight of fibers, especially cellulose fibers, based on the dry weight of the fibrous substrate body, - A fiber-based dry weight meter, at least one anionic polymer with a dry weight of 1% to 20%, especially a carboxylated polymer, the glass transition temperature T of the anionic polymer g is above -40 °C, and - 0.5% to 5% dry weight of at least one cationic precipitant, based on the dry weight of the fibers, Among them, The anionic polymer is present in the form of a precipitate on the surface of the fibers, characterized in that, The fibrous substrate body is provided with an anti-fouling layer on at least one of its main surfaces.

2. The anti-counterfeiting substrate according to claim 1, wherein The fibrous substrate body is respectively provided with anti-fouling films on its opposite main surfaces, and the fibrous substrate body and these two films together form a composite anti-counterfeiting substrate.

3. The anti-counterfeiting substrate according to claim 1, characterized in that, The fibrous substrate body is provided with an anti-fouling coating on at least one of its main surfaces.

4. The anti-counterfeiting substrate according to claim 3, wherein The anti-fouling coating consists of a composition that contains an acrylate system as the sole binder and does not contain filler materials.

5. The anti-counterfeiting substrate according to claim 3, wherein The anti-fouling coating is formed based on polyurethane.

6. The anti-counterfeiting substrate according to claim 5, characterized in that, The anti-fouling coating consists of a composition that includes 50% to 70% dry weight of a transparent or semi-transparent binder and 30% to 50% of silica, and optionally at least one functional additive, wherein the sum of the components mentioned constitutes 100% of the composition, and wherein the elastomeric binder is selected from polyurethanes that can be used in the form of a stable aqueous dispersion.

7. The anti-counterfeiting substrate according to claim 5, characterized in that, The anti-fouling coating consists of a composition that includes non-colored polyurethane and optionally at least one functional additive.

8. The anti-counterfeiting substrate according to at least one of claims 3 to 7, characterized in that, The anti-fouling coating includes a biocidal additive, especially a fungicidal, bactericidal, and / or virucidal additive, as a functional additive.

9. The anti-counterfeiting substrate according to at least one of claims 3 to 7, characterized in that, The anti-fouling coating includes a visual and / or machine-verifiable characteristic material as a functional additive.

10. The anti-counterfeiting substrate according to at least one of claims 1 to 9, characterized in that, The fibrous substrate body contains 0.001% to 1% dry weight of at least one biocide.

11. The anti-counterfeiting substrate according to at least one of claims 1 to 10, characterized in that, The anionic polymer of the fibrous substrate body is selected from carboxylated styrene-butadiene copolymers.

12. The anti-counterfeiting substrate according to at least one of claims 1 to 11, characterized in that, A partial or full internal printing layer is provided between the fibrous substrate body and at least one anti-fouling layer.

13. An anti-counterfeiting paper having the anti-counterfeiting substrate according to any one of claims 1 to 12, and having at least one partial or full external printing layer applied on the anti-fouling layer.

14. The anti-counterfeiting paper according to claim 13, wherein, The external printing layer is covered by other anti-fouling layers, especially anti-fouling coatings.

15. A method for manufacturing the anti-counterfeiting substrate according to any one of claims 1 to 12, wherein, - 40% to 96% dry weight of fibers, especially cellulose fibers, based on the dry weight of the fibrous substrate body, - A fiber-based dry weight meter, at least one anionic polymer having a dry weight of 1% to 20%, especially a carboxylated polymer, the glass transition temperature T of the anionic polymer g is above -40 °C, and - 0.5% to 5% dry weight of at least one cationic precipitant, based on the dry weight of the fibers, The anionic polymer is present in the form of a precipitate on the fiber surface, and - The fibrous substrate body is provided with an anti-fouling layer, especially an anti-fouling coating or an anti-fouling film, on at least one of its main surfaces.

16. The method according to claim 15, wherein Apply or print an anti-fouling coating having a unit area weight between 1 and 6 g / m 2 , particularly between 2 and 3 g / m 2 on one or both main surfaces of the fibrous substrate body.

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