Biodegradable value document substrate

Abstract

The invention relates to a biodegradable value document substrate comprising a biodegradable paper substrate having sustainable fibres, the sustainable fibres being selected from the group consisting of natural fibres, regenerated cellulose fibres, bio-based plant polymer fibres, bio-based animal polymer fibres, or a mixture of two or more of the aforementioned elements.

Description

[0001] Biodegradable value document substrate

[0002] The invention relates to a biodegradable value document substrate, in particular a banknote.

[0003] Security document substrates, especially banknotes, are exposed to high levels of stress during the course of security document circulation, leading to soiling and mechanical damage. With a view to increasing circulation stability, WO 2004 / 072378 A1 proposes providing security paper with a varnish-based protective layer. WO 2004 / 028825 A2 describes the provision of a security paper with improved soiling resistance and increased mechanical strength based on a multilayer substrate comprising at least one paper layer and a film.

[0004] The approaches taken in the state of the art to provide value document substrates with increased circulation stability are associated with the disadvantage that the necessary starting materials are of petrochemical origin, which raises difficulties in terms of recycling, environmental impact and sustainability.

[0005] The present invention is based on the object of overcoming the disadvantages of the prior art and providing an improved value document substrate. The value document substrate should, in particular, ensure sustainable and environmentally friendly disposal while simultaneously exhibiting high circulation stability. This object is achieved by the combination of features defined in the independent claim. Further developments of the invention are the subject of the dependent claims.

[0006] Summary of the invention

[0007] 1. A biodegradable security document substrate comprising a biodegradable paper substrate with sustainable fibers, wherein the sustainable fibers are selected from the group consisting of natural fibers, regenerated cellulose fibers, bio-based plant polymer fibers, bio-based animal polymer fibers, or a mixture of two or more of the aforementioned elements.

[0008] 2. (Preferred embodiment) Biodegradable security document substrate according to clause 1, wherein natural fibers are selected as sustainable fibers and the natural fibers are based on a mixture comprising cotton fibers and resistant fibers, wherein the resistant fibers are preferably obtained from plants selected from the group consisting of hemp, flax, flax, abaca, nettle, ramie, hops, sisal or a mixture of two or more of the aforementioned elements.

[0009] 3. (Preferred embodiment) Biodegradable value document substrate according to clause 2, wherein the paper substrate additionally contains bio-based plant polymer fibers as sustainable fibers, wherein the bio-based plant polymer fibers are bio-based polyamide fibers, beechwood fibers, Tencel fibers, castor fibers, polylactate fibers and / or protein fibers, wherein the protein fibers are obtained in particular from corn, peanut, milk and / or soy.

[0010] 4. (Preferred embodiment) Biodegradable security document substrate according to clause 2 or 3, wherein the paper substrate additionally contains bio-based animal polymer fibers as sustainable fibers, wherein the bio-based animal polymer fibers are based on sheep's wool, Merino wool, fine hair of the cashmere goat and / or alpaca wool.

[0011] 5. (Preferred embodiment) Biodegradable security document substrate according to clause 2, 3 or 4, wherein the paper substrate additionally contains regenerated cellulose fibres as sustainable fibres.

[0012] 6. (Preferred embodiment) Biodegradable value document substrate according to any one of clauses 2 to 5, wherein the cotton fibers have an average length and the resistant fibers have an average length, wherein the average length of the resistant fibers is higher than the average length of the cotton fibers by an amount in a range of 10% to 50%.

[0013] 7. (Preferred embodiment) Biodegradable value document substrate according to one of clauses 1 to 6, wherein the paper substrate is a two-layer paper substrate with a first paper layer and a second paper layer, wherein the first paper layer is based on fibers with an average length and the second paper layer is based on fibers with an average length, wherein the average length of the fibers of the second paper layer is higher by a certain amount than the average length of the fibers of the first paper layer, wherein the certain amount is in particular in a range of 10% to 50%. 8. (Preferred embodiment) Biodegradable value document substrate according to one of clauses 1 to 7, wherein the paper substrate additionally contains biopolymer-based, biodegradable stabilizers, in particular chitosan, and / or biodegradable excipients.

[0014] 9. (Preferred embodiment) Biodegradable value document substrate according to one of clauses 1 to 8, wherein the value document substrate is a multi-layer value document substrate with polymer layer / paper substrate / polymer layer structure or paper substrate / polymer layer / paper substrate structure, wherein the polymer layer is biodegradable and is selected in particular from the group consisting of cellulose, polybutylene adipate terephthalate (BTA copolyester), polylactide (PLA), in particular biaxially oriented polylactide, polyhydroxybutyrate (PHB), or a mixture of two or more of the aforementioned elements.

[0015] 10. (Preferred embodiment) Biodegradable value document substrate according to clause 9, wherein the value document substrate is a multi-layer value document substrate with a polymer layer / paper substrate / polymer layer structure and the polymer layer is in each case a film.

[0016] 11. (Preferred embodiment) Biodegradable value document substrate according to one of clauses 1 to 8, wherein the biodegradable paper substrate is provided on each of its two main surfaces with a biodegradable lacquer layer, wherein the biodegradable lacquer layer is selected in particular from the group consisting of polysugar, lignin, shellac, tree resin, polyvinylpyrrolidone (PVP), polyalcohol (PVA) or a mixture of two or more of the aforementioned elements.

[0017] 12. (Preferred embodiment) Biodegradable value document substrate according to one of clauses 1 to 11, wherein the value document substrate comprises a security thread and / or a security strip and / or a security patch based on a biodegradable material and / or mottled fibers based on natural fibers.

[0018] 13. (Preferred embodiment) A biodegradable value document substrate according to any one of clauses 1 to 12, wherein the value document substrate is a banknote.

[0019] Detailed description of the preferred embodiments

[0020] The invention is based on the finding that a sustainable value document substrate can be provided based on a biodegradable paper substrate containing sustainable fibers. The value document substrate according to the invention preferably consists essentially of sustainable, i.e., biodegradable, components, with particular preference for the value document substrate to consist exclusively of sustainable components.

[0021] The biodegradable value document substrate according to the invention comprises a biodegradable paper substrate with sustainable fibers, wherein the sustainable fibers are selected from the group consisting of natural fibers, regenerated cellulose fibers, bio-based plant polymer fibers, bio-based animal polymer fibers, or a mixture of two or more of the aforementioned elements. In this way, the value document substrate according to the invention can be disposed of or recycled in a sustainable and environmentally friendly manner at the end of its life cycle.

[0022] According to a preferred variant, the biodegradable paper substrate comprises natural fibers as sustainable fibers, wherein the natural fibers are based on a mixture comprising cotton fibers and resilient fibers, and the resilient fibers are preferably obtained from plants selected from the group consisting of hemp, flax, linen, abaca, nettle, ramie, hops, sisal, or a mixture of two or more of the aforementioned elements. It is particularly preferred that the cotton fibers have an average length and the resilient fibers have an average length, wherein the average length of the resilient fibers is higher than the average length of the cotton fibers by an amount in a range of 10% to 50%.In this way, a biodegradable value document substrate can be provided which is particularly advantageous compared to conventional value document substrates with regard to tear resistance and tear propagation resistance.

[0023] According to a further preferred variant, the paper substrate contains bio-based plant-based polymer fibers as sustainable fibers, wherein the bio-based plant-based polymer fibers are bio-based polyamide fibers, beechwood fibers, Tencel fibers, castor fibers, polylactate fibers, and / or protein fibers, wherein the protein fibers are obtained in particular from corn, peanuts, milk, and / or soy. Due to the enzymatic cleavage of the bio-based plant-based fibers, a biodegradable value document substrate can thus be provided, which is particularly advantageous in terms of biodegradability compared to conventional value document substrates.

[0024] According to a further preferred variant, the paper substrate contains bio-based animal polymer fibers as sustainable fibers, wherein the bio-based animal polymer fibers are based on sheep's wool, Merino virgin wool, fine cashmere goat hair, and / or alpaca wool. Due to the enzymatic cleavage of the bio-based animal fibers, a biodegradable security document substrate can be provided that is particularly advantageous in terms of biodegradability compared to conventional security document substrates.

[0025] According to a further preferred variant, the paper substrate contains regenerated cellulose fibers as sustainable fibers, wherein, according to a particularly preferred variant, the paper substrate consists essentially or exclusively of regenerated cellulose fibers with regard to the cellulose fibers contained therein. In this way, a biodegradable value document substrate can be provided that is particularly advantageous in terms of its ecological balance due to the use of recycled starting materials compared to conventional value document substrates.

[0026] According to a further preferred variant, the paper substrate is a two-layer paper substrate with a first paper layer and a second paper layer, wherein the first paper layer is based on fibers with an average length and the second paper layer is based on fibers with an average length, wherein the average length of the fibers of the second paper layer is higher by a certain amount than the average length of the fibers of the first paper layer, wherein the certain amount is in particular in a range of 10% to 50%. In this way, a biodegradable value document substrate with improved mechanical resistance can be provided, which can furthermore be provided with areas with a watermark texture in which predominantly short fibers are contained compared to the remaining areas. The provision of the multi-layer paper substrate can, for example,according to the manufacturing process described in WO 2006 / 099971 A2. Alternatively, the production can be carried out by spraying a paper layer based on long fibers onto a paper layer based on short fibers.

[0027] According to a further preferred variant, the paper substrate additionally contains biopolymer-based, biodegradable stabilizers, in particular chitosan, and / or biodegradable auxiliaries. In this way, a biodegradable value document substrate with reduced environmental impact can be provided.

[0028] According to a further preferred variant, the value document substrate is a multilayer value document substrate with a polymer layer / paper substrate / polymer layer structure or a paper substrate / polymer layer / paper substrate structure, wherein the polymer layer is biodegradable and is selected in particular from the group consisting of cellulose, polybutylene adipate terephthalate (BTA copolyester), polylactide (PLA), in particular biaxially oriented polylactide, polyhydroxybutyrate (PHB), or a mixture of two or more of the aforementioned elements. Due to the presence of the biodegradable polymer layer, the value document substrate exhibits both improved mechanical strength and exceptionally advantageous resistance to contamination, as well as environmentally friendly, biodegradability.According to a particularly preferred variant, the value document substrate is a multilayer value document substrate with a polymer layer / paper substrate / polymer layer structure, wherein each polymer layer is a film. A value document substrate with a polymer layer / paper substrate / polymer layer structure, also referred to as a film composite substrate, is known from WO 2004 / 028825 A2.

[0029] According to a further preferred variant, the value document substrate according to the invention is designed such that the biodegradable paper substrate is provided with a biodegradable lacquer layer on each of its two main surfaces, wherein the biodegradable lacquer layer is selected in particular from the group consisting of polysugar, lignin, shellac, tree resin, polyvinylpyrrolidone (PVP), polyalcohol (PVA), or a mixture of two or more of the aforementioned elements. In this way, a value document substrate can be provided that exhibits both exceptionally advantageous resistance to soiling and environmentally friendly biodegradability.

[0030] According to a further preferred variant, the value document substrate according to the invention is designed such that it comprises a security thread and / or a security strip and / or a security patch based on a biodegradable material and / or mottled fibers based on natural fibers. In this way, a value document substrate that is particularly advantageous in terms of recyclability can be provided.

[0031] The value document substrate according to the invention is, in particular, a banknote or a security paper suitable for producing banknotes. Further embodiments and advantages of the invention are explained below with reference to the figures, which are not drawn to scale or proportions to enhance clarity.

[0032] They show:

[0033] Figure 1 shows a value document substrate according to a first embodiment in plan view;

[0034] Figure 2 shows a value document substrate according to a second embodiment in plan view;

[0035] Figure 3 shows a section along line AB of the value document substrate shown in Figure 2;

[0036] Figure 4 shows a value document substrate according to a third embodiment in plan view;

[0037] Figure 5 shows a section along the line AB of the value document substrate shown in Figure 4;

[0038] Figure 6 shows a value document substrate according to a fourth embodiment in plan view;

[0039] Figure 7 shows a section along line AB of the value document substrate shown in Figure 6; Figure 8 shows a value document substrate according to a fifth embodiment in plan view;

[0040] Figure 9 shows a section along the line AB of the value document substrate shown in Figure 8;

[0041] Figure 10 shows a value document substrate according to a sixth embodiment in plan view;

[0042] Figure 11 is a side view of the value document substrate shown in Figure 10; and

[0043] Figure 12 shows a cross section through a value document substrate according to the invention.

[0044] Figure 1 illustrates a top view of a biodegradable value document substrate 0 according to the invention, in the example a banknote with a denomination of 20, according to a first exemplary embodiment. The banknote 0 contains a biodegradable paper substrate based on natural fibers as sustainable fibers. The sustainable fibers used are a mixture comprising cotton fibers and resistant fibers, namely abaca fibers, wherein the average length of the abaca fibers is 20% longer than the average length of the cotton fibers. The banknote 0 also contains a polylactide (PLA)-based, metallized security thread (denoted in the figure by a black, solid line) and a polylactide (PLA)-based security patch (denoted in the figure by a gray area). Figure 2 shows a top view of a value document 1 according to the invention, in the example a banknote, according to a second exemplary embodiment.The paper layer consists of a mixture based on cotton fibers and fibers from the hemp plant as resistant fibers. During production of the paper layer, individual security elements are already embedded in the paper, namely a portrait watermark 2 and a window security thread 3. The polylactide (PLA)-based, metallized security thread 3 is woven into the paper, so to speak, so that in areas 3a it comes directly to the surface of the paper, while in the dashed areas it is completely embedded in the paper pulp. The paper layer is covered on both sides with a polylactide (PLA)-based film, with a polylactide (PLA)-based hologram strip 8 applied to one side, namely the inner side of the film. A series of numbers commonly used in banknote printing was printed on the outer side of the film using steel intaglio printing.

[0045] Figure 3 shows a section through the banknote 1 according to the invention along the dash-dotted line AB shown in Figure 2. The banknote 1 according to the invention consists of biodegradable paper 4 and biodegradable films 6, which, according to the embodiment shown, were laminated over the entire surface of the paper 4 using wet adhesive 5. Alternatively, only one film 6 can be applied to one side of the paper 4. The upper film 6 was provided with a hologram strip 8 before lamination. The upper film 6 was laminated to the paper 4 in such a way that the strip 8 lies inside the substrate composite. In a final step, the imprint 7 was printed onto the resulting film / paper / foil composite substrate using an intaglio printing process.

[0046] Figures 4 and 5 show a value document substrate 9 according to the invention, in this example a banknote, according to a third exemplary embodiment. Figure 5 shows a section through the banknote 9 along the dot-dash line AB in Figure 4.

[0047] As shown in Figure 5, the banknote 9 consists of a divided, biodegradable paper web 10, the edges 12 of which are preferably designed as deckle-edge paper. Biodegradable foils 13 were applied to both sides of the paper web by means of cold lamination and water-curing adhesive 5. In area 11, there is no paper layer, but only the adhesive 5 and the foils 13. One foil layer is equipped on one side with a highly reflective metal strip 14. In addition, a feature substance 15 is located within the volume of the paper, which can be checked visually or mechanically. The feature substance can, for example, be a luminescent substance that is transparent under normal lighting and emits light in the visible spectral range when irradiated with UV light, thus exhibiting an intense color.

[0048] However, it is also possible to specify multiple attribute substances that can be detected individually. In this case, additional coding can be generated by the mixing ratio of the attribute substances.

[0049] Figures 6 and 7 show a fourth embodiment of a banknote 16 according to the invention. Figure 7 shows a section through the banknote 16 according to the invention along the dot-dash line AB in Figure 6. Figure 6 shows, in plan view, three wide strips 17, 18, 19, each having a different optical appearance and incorporated in different layers of the foil / paper / foil composite substrate.

[0050] Fig. 7 shows the cross-section of banknote 16. The biodegradable paper layer 21 is conventionally printed using steel intaglio printing in the form of stripe 17. A transparent adhesive layer 20 is applied over it. A second, colored adhesive layer is applied in area 18, forming stripe 18. The adhesive layers 18, 20 are in turn covered with a biodegradable film 22, on the inside of which is a hologram stripe 19. A further biodegradable film 23 is laminated to the reverse side using the transparent adhesive 20.

[0051] Figure 8 shows a section of the banknote 24 according to the invention, with different security features arranged in register in different layers, resulting in the overall information "SAMPLE" in combination with a two-color metallic annulus. The annulus is divided into four segments, with segments 25a being gold-colored and segments 25b being silver-colored. The gold and silver colors are achieved, for example, by vacuum deposition of copper and aluminum. Additionally, recesses were incorporated into the metal layer in segments 25b, namely the letter "U" on the one hand and the letter "E" on the other. The letters "M", "S", "T", and "R" were applied by intaglio printing, with "S" and "T" printed on the paper surface and "M" and "R" printed on the outer foil surface.In region 26, a luminescent substance is incorporated into the paper volume, excitable with UV light, and fluorescent in visible light. Figure 9 shows the section of the banknote 24 according to the invention shown in Figure 8 in cross-section. The banknote is composed of a biodegradable paper layer 28 and two biodegradable film layers 27a, 27b, each laminated to one side of the paper layer. A luminescent substance 29 has been incorporated into the paper layer 28 in the circular region 26.

[0052] The letters "S" and "T" were printed on the paper layer using an intaglio printing process, positioned above area 26. The foil 27b is also equipped with security features. On the side facing the inner layer of the layered assembly, the foil was coated with a gold and silver-colored metallization, e.g., aluminum and copper, in the shape of a segmented circular ring. Cutouts in the shape of the letters "U" and "E" were incorporated into the silver-colored area 25b. The letters "M" and "R" were printed on the outer surfaces of the foil 27b using an intaglio printing process.

[0053] Figure 10 shows a top view of a banknote 30 according to the invention. The banknote consists of a biodegradable paper layer 31 and two biodegradable film layers 32a, 32b, each laminated to one side of the paper layer.

[0054] Figure 11 shows the banknote 30 shown in Figure 10 in cross section.

[0055] The foils 32a and 32b are fully transparent. The paper layer 31 has two recesses 33, 34 in the shape of circles. Of course, any other shape is also conceivable. Furthermore, the foil 32a is printed with the letters "A," "L," and "V," which appear mirror images when viewed from above as shown in Figure 10. Approximately in the center of the banknote, the letters "I" and "D" are printed on the paper layer 31.

[0056] If the banknote is folded along the dot-dashed lines C-C and EE so that the left and right thirds of the banknote are folded upward and lie on top of each other, the printed letters complement each other to form the "VALID" typeface. For simplicity, the overlapping fields in Figure 10 are marked with circles (solid line or dashed line). Of course, the complementary prints can also be more complex or, with appropriate design, create moiré effects and similar patterns.

[0057] Figure 12 shows a banknote 40 according to the invention in cross section.

[0058] The banknote consists of a biodegradable paper layer 41 and a biodegradable film 42, which are laminated together with three different adhesives 43, 44, and 45. The adhesives can be of different colors or types. In the present variant, the adhesives 43, 44, and 45 exhibit different adhesion properties to one another, allowing for targeted predetermined breaking points to be incorporated into the composite, and tampering due to irreversible changes is easily detectable.

[0059] It is also conceivable to use adhesives with different refractive indices, so that, for example, individual contours in the area of ​​a watermark can be specifically emphasized or weakened. Patent claims

[0060] 1. A biodegradable security document substrate comprising a biodegradable paper substrate with sustainable fibers, wherein the sustainable fibers are selected from the group consisting of natural fibers, regenerated cellulose fibers, bio-based plant polymer fibers, bio-based animal polymer fibers, or a mixture of two or more of the aforementioned elements.

[0061] 2. Biodegradable value document substrate according to claim 1, wherein natural fibers are selected as sustainable fibers and the natural fibers are based on a mixture comprising cotton fibers and resistant fibers, wherein the resistant fibers are preferably obtained from plants selected from the group consisting of hemp, flax, linen, abaca, nettle, ramie, hops, sisal or a mixture of two or more of the aforementioned elements.

[0062] 3. Biodegradable value document substrate according to claim 2, wherein the paper substrate additionally contains bio-based plant polymer fibers as sustainable fibers, wherein the bio-based plant polymer fibers are bio-based polyamide fibers, beechwood fibers, Tencel fibers, castor fibers, polylactate fibers and / or protein fibers, wherein the protein fibers are obtained in particular from corn, peanut, milk and / or soy.

[0063] 4. Biodegradable value document substrate according to claim 2 or 3, wherein the paper substrate additionally contains bio-based animal polymer fibers as sustainable fibers, wherein the bio-based animal poly-

Claims

Merino fibres are based on sheep's wool, Merino virgin wool, fine hair of the cashmere goat and / or alpaca wool.

5. Biodegradable value document substrate according to claim 2, 3 or 4, wherein the paper substrate additionally contains regenerated cellulose fibers as sustainable fibers.

6. Biodegradable value document substrate according to one of claims 2 to 5, wherein the cotton fibers have an average length and the resistant fibers have an average length, wherein the average length of the resistant fibers is higher than the average length of the cotton fibers by an amount in a range of 10% to 50%.

7. Biodegradable value document substrate according to one of claims 1 to 6, wherein the paper substrate is a two-layer paper substrate with a first paper layer and a second paper layer, wherein the first paper layer is based on fibers with an average length and the second paper layer is based on fibers with an average length, wherein the average length of the fibers of the second paper layer is higher than the average length of the fibers of the first paper layer by a certain amount, wherein the certain amount is in particular in a range of 10% to 50%.

8. Biodegradable value document substrate according to one of claims 1 to 7, wherein the paper substrate additionally contains biodegradable stabilizers based on biopolymers, in particular chitosan, and / or biodegradable auxiliaries.

9. Biodegradable value document substrate according to one of claims 1 to 8, wherein the value document substrate is a multi-layer value document substrate with a polymer layer / paper substrate / polymer layer structure or paper substrate / polymer layer / paper substrate structure, wherein the polymer layer is biodegradable and is selected in particular from the group consisting of cellulose, polybutylene adipate terephthalate (BTA copolyester), polylactide (PLA), in particular biaxially oriented polylactide, polyhydroxybutyrate (PHB), or a mixture of two or more of the aforementioned elements.

10. Biodegradable value document substrate according to claim 9, wherein the value document substrate is a multilayer value document substrate with a polymer layer / paper substrate / polymer layer structure and the polymer layer is in each case a film.

11. Biodegradable value document substrate according to one of claims 1 to 8, wherein the biodegradable paper substrate is provided on each of its two main surfaces with a biodegradable lacquer layer, wherein the biodegradable lacquer layer is selected in particular from the group consisting of polysugar, lignin, shellac, tree resin, polyvinylpyrrolidone (PVP), polyalcohol (PVA) or a mixture of two or more of the aforementioned elements.

12. Biodegradable value document substrate according to one of claims 1 to 11, wherein the value document substrate comprises a security thread and / or a security strip and / or a security patch based on a biodegradable material and / or mottled fibers based on natural fibers.

13. Biodegradable value document substrate according to one of claims 1 to 12, wherein the value document substrate is a banknote.

Images