Security document with embedded watermark and method of producing it

Abstract

The invention relates to a security document A) with a first outer surface AS1) and a second outer surface AS2) opposite the first outer surface AS1), comprising at least: (A1) a first polymer film A1), (A2) a second polymer film A2), (A3) optionally at least one further transparent or translucent polymer film A3), (A4) a security feature A4), (A5) optionally particles, wherein at least one of the polymer films selected from the group consisting of the first polymer film A1), the second polymer film A2), optionally the at least one further polymer film A3), or a combination of at least two thereof, comprises a thermoplastic elastomer TPE or consists of at least one TPE and forms at least one of the outer surfaces AS1) or AS2).wherein at least one of the polymer films A1) or A2) is translucent at least in the area where the security feature A4) is located and the other polymer film A1) or A2) is transparent or translucent, characterized in that the security feature A4) is an engraving, in particular a laser engraving, in the second polymer film A2) which is designed in such a way that it has the function of a watermark, as well as its manufacturing process and its use as a banknote, birth certificate, postage stamp, tax stamp, visa pages of a passport, hinge for the data page of a passport or as a carrier layer of an electromagnetic shield in the passport.

Description

[0001] The invention relates to a security document A) comprising at least two polymer films A1) and A2), optionally further polymer films A3), a security feature A4), optionally particles A5), wherein the security feature A4) is a watermark in the form of a (laser) engraving in the second polymer film A2), which is visible when viewed in transmitted light from at least one side of the security document A) and is not visible when viewed in reflected light without transmitted light onto the security document A), as well as a method for producing the security document A) and its use as a banknote, birth certificate, postage stamp, tax stamp, visa pages of a passport, hinge for the data page of a passport or carrier layer of an electromagnetic shield in the passport.

[0002] Substrates for security documents such as identification documents, for example passports or identity cards, or valuable documents like banknotes are subject to constant development to meet the ever-increasing demands for durability, efficiency, counterfeit protection, and sustainability. Developments are now underway to manufacture the aforementioned security documents predominantly or entirely from polymeric materials, especially TPEs. The challenge now lies in incorporating security features into these polymeric materials, as polymeric materials are not as easily die-cut as conventional paper, which is frequently used in security documents such as passports or banknotes.

[0003] Therefore, one object of the invention was to provide a security document that does not have easily forged security features. A further object of the invention was to provide a method for producing such forgery-proof security documents from polymeric materials.

[0004] Furthermore, an object of the invention was to provide a security document that meets the currently prevailing requirements for durability, efficiency, tamper resistance, and sustainability, and in particular, that none of these requirements are met with a lower quality than can be derived from the current state of the art. In addition, an object of the invention was to provide an optimized, and in particular more cost-effective, method for a security document with the aforementioned advantages.

[0005] A first object of the invention relates to a security document A) with a first outer surface AS1) and a second outer surface AS2) opposite the first outer surface AS1) comprising at least: (A1) a first polymer film A1), (A2) a second polymer film A2), (A3) optionally at least one further transparent or translucent polymer film A3), (A4) a security feature A4), (A5) optional particles, wherein at least one of the polymer films selected from the group consisting of the first polymer film A1), the second polymer film A2), optionally the at least one further polymer film A3) or a combination of at least two thereof, contains a thermoplastic elastomer TPE or consists of at least one TPE and forms at least one of the outer surfaces AS1) or AS2), wherein at least one of the polymer films A1) or A2) is translucent at least in the area in which the security feature A4) is located and the other polymer film A1) or A2) is transparent or translucent, characterized in that the security feature A4) is an engraving, in particular a laser engraving, in the second polymer film A2), wherein the engraving is incorporated into the security document in such a way that it has the function of a watermark.

[0006] According to the invention, a watermark is a pattern that stands out optically against the material surrounding it when viewed in transmitted or backlit light. Therefore, the security document A) should be translucent at least in the area where the security feature A4) is located, so that the engraving can stand out optically against the surrounding material. Preferably, the engraving appears darker against the surrounding material.

[0007] The engraving, in particular the laser engraving in the second polymer film A2), is designed such that it is visible from at least one side of the security document A) when viewed with transmitted light. Preferably, the engraving is barely visible or not visible at all from at least one side of the security document A) when viewed with reflected light without backlighting or transmitted light. According to the invention, "barely visible" means that the engraving is only vaguely discernible to the naked eye without transmitted light from at least one side of the security document A), i.e., it is not recognizable without knowledge of the watermark pattern. Reflected light means that the security document A) is only illuminated by light striking it from the viewer's side.Transmitted light is understood to mean that light from a simple light source, such as a lamp, for example a flashlight or an LED light with sufficient luminous flux, advantageously between 20 and 100 W, or the sun, is directed through the security document A) to the viewer of the security document A).

[0008] If the security document A) has only a first polymer film A1) and a second polymer film A2), then the watermark in the form of an engraving, as security feature A4), is located in polymer film A2) directly on the surface formed between the two polymer films A1) and A2). If polymer film A2) is translucent and polymer film A1) is transparent, then security feature A4) is visible in both reflected and transmitted light when viewed from the side of polymer film A1). When viewed from the side of polymer film A2), security feature A4) is only visible in transmitted light.

[0009] If the security document A) has, in addition to a first polymer film A1) and a second polymer film A2), also a further polymer film A3), the watermark in the form of an engraving, as security feature A4), is located in polymer film A2) directly on one of the surfaces formed between the two polymer films A1) and A2) or between polymer films A2) and A3). If only one of the polymer films A2), A2), or A3) is translucent and the other two polymer films A1), A2), or A3) are transparent, then security feature A4) is visible from one side in both reflected and transmitted light, and from the other side only in transmitted light, but not in reflected light, because there is translucent material between security feature A4) and the viewer.If the viewer is to be able to see the security feature A4) in the form of the watermark from both sides of the security document A) only in transmitted light, but not in reflected light, then at least two of the at least three polymer films A1), A2) or A3) must be translucent at least in the area of ​​the security feature A4).

[0010] If the security feature A4) is located on the surface between polymer film A1) and A2), then polymer film A1) must be translucent and at least one of the other two polymer films A2) or A3) must be translucent in order to be able to see the watermark only in transmitted light.

[0011] If the security feature A4) is located on the surface between polymer film A2) and A3), then polymer film A3) must be translucent and at least one of the other two polymer films A1) or A2) must be translucent in order to be able to see the watermark only in transmitted light.

[0012] All other optional polymer films A3) can be transparent or translucent. According to the invention, translucent means that light directed at the security document A) penetrates the security document A) only to a small extent and is scattered to a significant degree within the material of the security document A), so that no objects on the other side of the security document A) are visible. Preferably, the security document A) has a transmission in the area where the security feature A4) is located in the range of 1 to 50%, more preferably 2 to 40%, and more preferably 5 to 30%, and more preferably 10 to 20%. The transmission was measured according to ASTM D1003 (light type C, measuring instrument: Byk Gardner) unless otherwise specified.Preferably, the security document A) has the specified transmission values ​​across its entire surface, except in areas where printing inks or other applied materials render the security document A) opaque, at least in those areas.

[0013] Preferably, the further polymer films A2) and A3) are transparent or translucent. Preferably, at least one of the polymer films selected from polymer film A1), at least one of the further polymer films A3), and all of the polymer films A1) and A3) each independently exhibit a transmission in the range of 50 to 80%, more preferably 55 to 75%, and particularly preferably 60 to 70%.

[0014] The security document A) can have any shape that a person skilled in the art would choose for a security document A). Preferably, the security document A) has a planar dimension in the form of a square, a rectangle, a circle, an oval, or a polyhedron, particularly preferably in the form of a square or a rectangle.

[0015] The security document A) preferably has a thickness in the range of 40 to 250 µm, more preferably in the range of 50 to 200 µm, further preferably in the range of 60 to 150 µm, more preferably in the range of 70 to 100 µm.

[0016] The aspect ratio between the thickness of the security document A) and its area is preferably in a range of 1:100000 to 1:1000, more preferably in a range of 1:50000 to 1:500, and particularly preferably in a range of 1:10000 to 1:100.

[0017] The first polymer film A1) preferably has a thickness in the range of 10 to 100 µm, more preferably in the range of 12 to 90 µm, more preferably in the range of 15 to 50 µm, more preferably in the range of 20 to 40 µm.

[0018] The second polymer film A2) preferably has a thickness in the range of 10 to 150 µm, more preferably in the range of 20 to 100 µm, more preferably in the range of 30 to 80 µm, more preferably in the range of 40 to 60 µm.

[0019] The further polymer film A3) preferably has a thickness in the range of 10 to 100 µm, more preferably in the range of 12 to 90 µm, more preferably in the range of 15 to 50 µm, more preferably in the range of 20 to 40 µm.

[0020] At least one polymer film selected from the group consisting of the first polymer film A1), A2) and A3) preferably has a length in the range of 1 to 100 cm, more preferably in the range of 2 to 80 cm, and particularly preferably in the range of 5 to 50 cm.

[0021] At least one polymer film selected from the group consisting of the first polymer film A1), A2) and A3) preferably has a width in a range of 1 to 100 cm, more preferably in a range of 2 to 80 cm, and particularly preferably in a range of 5 to 50 cm.

[0022] Preferably, the polymer films A1) and A2) and preferably also A3) are congruent in their planar expansion direction.

[0023] The security document A) preferably has a width in the range of 5 to 500 cm, more preferably in the range of 10 to 200 cm, and most preferably in the range of 15 to 50 cm.

[0024] The security document A) preferably has a height in the range of 5 to 500 cm, more preferably in the range of 10 to 200 cm, and most preferably in the range of 15 to 50 cm.

[0025] The safety document A) preferably has an area in a range of 25 to 250000 cm², more preferably in a range of 150 to 50000 cm², and particularly preferably in a range of 200 to 5000 cm².

[0026] The security document A) can be any security document that a person skilled in the art would use to introduce a security feature A4). The security document A) is preferably selected from the group consisting of a banknote, a birth certificate, a postage stamp, a revenue stamp, a visa page of a passport, a hinge for the data page of a passport, a carrier layer of an electromagnetic shield in a passport, or a combination of at least two of these.

[0027] Preferably, both outer surfaces AS1) and AS2) comprise a TPE. Preferably, both outer surfaces AS1) and AS2) consist of a TPE. Preferably, both outer surfaces AS1) and AS2) are each formed by a polymer film A1). More preferably, the polymer film A2) forms the core of a film structure of at least three layers in which the outer surfaces AS1) and AS2) are each formed by a polymer film A1).

[0028] Preferably, at least one of the polymer films A1), A2), and optionally A3), in particular the first polymer film A1), comprises a material suitable for generating an adhesive force with the adjacent polymer film A2) or the next polymer film A3) that is greater than the elongation at break of at least one of the polymer films A1), A2), or A3). The adhesive force is higher than the tensile strength of the respective polymer film if one of the polymer films A1), A2), or A3) cannot be separated from the adjacent polymer film without leaving residue. This means that when the first polymer film A1) is separated from the second polymer film A2), or the second polymer film A2) from the next polymer film, at least one of the polymer films A1), A2), or A3) undergoes a cohesive failure and not an adhesive failure in which the adhesive force would be lower than the tensile strength of the polymer films.In contrast to an adhesion failure, which would represent a separation of the security document A) at the adhesion surface between the respective films and would allow the films to be separated from each other without leaving any residue, a cohesive failure occurs inside the layer and leaves residues of the polymer material on the respective film that is to be separated.

[0029] Preferably, the polymer films A1), A2), and optionally A3) exhibit an adhesive force to their respective adjacent polymer film of at least 2 N / cm, more preferably at least 3 N / cm, and particularly preferably at least 5 N / cm. More preferably, the polymer films A1), A2), and optionally A3) exhibit an adhesive force to their respective adjacent polymer film in the range of 2 to 20 N / cm, more preferably at least 3 N / cm to 15 N / cm, and particularly preferably at least 5 N / cm to 10 N / cm, measured according to ASTM D903-1998 at a tensile angle of 180°.

[0030] The optional particles A5) can be any type of particles that a person skilled in the art would use for inclusion in a safety document A). Preferably, the particles are selected from the group consisting of particles containing Sc, Y, La, Ce, Pr, Nd, Pm, Sm, EU, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, in particular Ce, La, Y and Gd, and their oxides, in particular CeO₂, La₂O₃ or Y₂O₃, Gd₂O₃. The safety document A) preferably includes the particles in an amount in the range of 5 ppm to 1000 ppm, more preferably 10 to 500 ppm. The particles can be included in any of the polymer films A1), A2), or optionally A3). Examples of such rare earth particles are products of Intelligent Materials Pvt. Ltd., such as the Cerium Oxide Nanopowder (CAS number: 1306-38-3), the Lanthanum Oxide Nanopowder (CAS number: 1312-81-8), the Yttrium Oxide Nanopowder (CAS number: 1314-36-9) or the Gadolinium Oxide Nanopowder (CAS number: 12064-62-9).Such particles produce a special light effect and can therefore also be used as a recognition feature or security feature.

[0031] In a preferred embodiment of safety document A), the TPE is selected from the group consisting of a copolyester elastomer (TPC), a thermoplastic polyamide elastomer (TPA), in particular a polyether block amide (PEBA), a thermoplastic olefin-based elastomer (TPO), in particular PP / EPDM, a thermoplastic polyurethane (TPU), a thermoplastic polycarbonate (PC), a polyethylene terephthalate (PET), in particular a polyethylene terephthalate glycol (PETG), a thermoplastic styrene block copolymer (TPS), in particular a styrene-butadiene block copolymer (SBC), or a mixture of at least two thereof. TPEs are elastomers that behave like classic elastomers at room temperature but become deformable when heated. They are usually copolymers consisting of a soft elastomeric component and a hard thermoplastic component.

[0032] Suitable Copolyester elastomers TPC(segmented polyester elastomers), hereinafter also simply called copolyesters, are, for example, composed of a multitude of recurring short-chain ester units and long-chain ester units joined by ester bonds, the short-chain ester units comprising about 15-80 wt% of the copolyester and having the formula (I). in which R represents a divalent residue of a dicarboxylic acid with a molecular weight of less than about 350 g / mol, D represents a divalent residue of an organic diol with a molecular weight of less than about 250 g / mol; The long-chain ester units make up about 20 to 85 wt.%, preferably 30 to 70 wt.%, particularly preferably 35 to 60 wt.% of the copolyester and preferably have formula II: in which R represents a divalent residue of a dicarboxylic acid with a molecular weight of less than about 350 g / mol, and G represents a divalent residue of a long-chain glycol with an average molecular weight of about 350 to 6000 g / mol.

[0033] The usable copolyesters can be produced by polymerizing together a) one or more dicarboxylic acids, b) one or more linear, long-chain glycols and c) one or more low molecular weight diols.

[0034] The dicarboxylic acids used to produce the copolyester are aromatic acids with 8-16 carbon atoms, especially phenylenedicarboxylic acids such as phthalic, terephthalic and isophthalic acid.

[0035] The low-molecular-weight diols used to form the short-chain ester units of copolyesters belong to the classes of acyclic, alicyclic, and aromatic dihydroxy compounds. Preferred diols have 2–15 carbon atoms, such as ethylene, propylene, tetramethylene, isobutylene, pentamethylene, 2,2-dimethyltrimethylene, hexamethylene, and decamethylene glycols, dihydroxycyclohexane, cyclohexanediethanol, resorcinol, hydroquinone, and the like. Bisphenols suitable for this purpose include bis-(p-hydroxy)diphenyl, bis-(p-hydroxyphenyl)methane, bis-(p-hydroxyphenyl)ethane, and bis-(p-hydroxyphenyl)propane.

[0036] The long-chain glycols used to produce the soft segments of the copolyesters preferably have molecular weights of approximately 600 to 3000 g / mol. These include poly(alkylene ether) glycols in which the alkylene groups have 2-9 carbon atoms.

[0037] Glycol esters of poly(alkylene oxide) dicarboxylic acids or polyester glycols can also be used as long-chain glycols.

[0038] Long-chain glycols also include polyformals obtained by reacting formaldehyde with glycols. Polythioether glycols are also suitable. Polybutadiene and polyisoprene glycols, copolymers thereof, and saturated hydrogenation products of these materials represent satisfactory long-chain polymeric glycols.

[0039] Methods for the synthesis of such copolyesters are known from DE-OS 2 239 271, DE-OS 2 213 128, DE-OS 2 449 343 and US-A 3 023 192. Examples of suitable TPCs are the polyether elastomers Hytrel® from DuPont™ (Germany) and Keyflex® from LG Chemicals (Europe), preferably those with a hardness in the range of 45 to 95 Shore D.

[0040] The thermoplastic polyamide elastomer (TPA)The TPA can be any that a person skilled in the art would select for this purpose. The TPA is preferably a polyether block amide (PEBA). Suitable PEBAs are, for example, those consisting of polymer chains composed of repeating units according to formula (III). in which A is the polyamide chain derived from a polyamide with two carboxyl end groups by the loss of the latter, and B is the polyoxyalkylene glycol chain derived from a polyoxyalkylene glycol with terminal OH groups by the loss of the latter, and n is the number of units forming the polymer chain. The end groups are preferably OH groups or residues of compounds that terminate the polymerization.

[0041] The dicarboxylic acid polyamides with terminal carboxyl groups are obtained in a known manner, for example by polycondensation of one or more lactams and / or one or more amino acids, or by polycondensation of a dicarboxylic acid with a diamine, each in the presence of an excess of an organic dicarboxylic acid, preferably with terminal carboxyl groups. During the polycondensation, these carboxylic acids become part of the polyamide chain and, in particular, attach to its ends, yielding a µ-dicarboxylic acid polyamide. Furthermore, the dicarboxylic acid acts as a chain-terminating agent, which is why it is also used in excess.

[0042] The polyamide can be obtained starting from lactams and / or amino acids with a hydrocarbon chain consisting of 4-14 C atoms, such as caprolactam, oenantholactam, dodecalactam, undecanolactam, decanolactam, 11-aminoundecano or 12-aminododecanoic acid.

[0043] Examples of polyamides formed by polycondensation of a dicarboxylic acid with a diamine include the condensation products of hexamethylenediamine with adipine, azelaic, sebacic, and 1,12-dodecanedioic acid, as well as the condensation products of nonamethylenediamine and adipic acid, preferably those representatives thereof with a hardness in the range of 45 to 95 Shore D.

[0044] The dicarboxylic acids used for the synthesis of polyamide, on the one hand to fix a carboxyl group at each end of the polyamide chain and on the other hand as chain termination agents, include those with 4-20 C atoms, in particular alkanoic acids such as succinic, adipic, corkic, azelaic, sebacic, undecanedioic or dodecanedioic acid, and also cycloaliphatic or aromatic dicarboxylic acids such as terephthalic or isphthalic or cyclohexane-1,4-dicarboxylic acid.

[0045] The polyoxyalkylene glycols containing terminal OH groups are unbranched or branched and have an alkylene residue with at least two carbon atoms. Preferably, these are polyoxyethylene, polyoxypropylene, and polyoxytetramethylene glycols, as well as copolymers thereof.

[0046] The average molecular weight of these OH group-terminated polyoxyalkylene glycols can range widely, advantageously between 100 and 6000 g / mol, and particularly between 200 and 3000 g / mol.

[0047] The weight fraction of polyoxyalkylene glycol, based on the total weight of the polyoxyalkylene glycol and dicarboxylic acid polyamide used to produce the PEBA polymer, is 5-85 wt.%, preferably 10-50 wt.%.

[0048] Methods for the synthesis of such PEBA polymers are known from FR-PS 7 418 913, DE-OS 28 02 989, DE-OS 28 37 687, DE-OS 25 23 991, EP-A 095 893, DE-OS 27 12 987 and DE-OS 27 16 004 respectively.

[0049] PEBA polymers that, unlike those described previously, have a statistical structure are particularly suitable. These polymers are produced from a mixture of: 1. one or more polyamide-forming compounds from the group of α-aminocarboxylic acids or lactams with at least 10 carbon atoms, 2. an α,ω-dihydroxy-polyoxyalkylene glycol, 3. at least one organic dicarboxylic acid in a weight ratio of 1:(2+3) between 30:70 and 98:2, wherein hydroxyl and carbonyl groups are present in (2+3) in equivalent amounts, in the presence of 2 to 30 wt% water, based on the polyamide-forming compounds of group 1, heated under the resulting intrinsic pressure to temperatures between 23°C and 30°C and subsequently, after removal of the water, further processed under exclusion of oxygen at normal pressure or under reduced pressure at 250 to 280°C.

[0050] The TPO can be any TPO that a person skilled in the art would select for a safety document according to the invention (A). Examples of TPOs are thermoplastic olefins of the KEYFLEX® type from LG Chemicals (Europe), such as KEYFLEX® TP-1045D. Preferably, the TPO is a PP / EPDM. Examples of these TPO types are Santoprene™ from Advanced Elastomer Systems Ltd., a subsidiary of ExxonMobil Chemical Europe (Belgium), Saxomer® TPE-O from PCW GmbH (Germany), and Elastron TPO from Elastron (Turkey / Germany), preferably those with a hardness in the range of 45 to 95 Shore D.

[0051] The thermoplastic polyurethane (TPU) can be any TPU that the person skilled in the art would select for the safety document A) according to the invention.

[0052] A preferred method for producing thermoplastic polyurethane polymers is one that involves reacting the components (A) one or more substantially linear polyols, wherein the total amount of component (A) has an average molecular weight in the range of 500 g / mol to 5000 g / mol, (B) one or more organic polyisocyanates, preferably organic diisocyanates, (C) one or more linear diols having a molecular weight of 62 g / mol to 500 g / mol, (D) optionally in the presence of one or more catalysts, (E) optionally in the presence of one or more additives, auxiliary and / or adjuvants, and (F) optionally in the presence of one or more monofunctional chain terminators, wherein the process preferably comprises or consists of the following steps: 1) Providing and reacting a mixture of the total amount of component (A), a subset of component (B), and optionally a subset or the total amount of component (D), component (E), and / or component (F) to form an NCO-functional prepolymer, wherein in process step 1) a molar ratio of component (B) to component (A) in the range of 1.1 : 1.0 to 5.0 : 1.0 is present; 2) reacting the NCO-functional prepolymer from process step 1) with the total amount of component (C) to obtain an OH-functional prepolymer, optionally in the presence of a further subset of component (D), component (E), and / or component (F); 3) reacting the OH-functional prepolymer with the remaining amount of component (B) and optionally the remaining amount of component (D), component (E), and / or component (F) to obtain the thermoplastic polyurethane.where, across all process steps, the molar ratio of component (B) to the sum of component (A) and component (C) is in the range of 0.9 : 1.0 to 1.2 : 1.0.

[0053] The preferred method makes it possible to produce thermoplastic polyurethanes with good processing properties and good mechanical properties over a hardness range of approximately 45 Shore D to approximately 95 Shore D, achieving good coupling of the hard and soft phases of the TPU, which leads to an optimally high molecular weight and thus to very good mechanical properties of the manufactured workpieces.

[0054] In the context of the present invention, the word "a" in connection with countable quantities is to be understood as a numeral only when this is expressly stated (e.g., by the expression "exactly one"). For example, when the following text refers to "a polyol," the word "a" is to be understood merely as an indefinite article and not as a numeral; thus, it also includes an embodiment containing a mixture of at least two polyols.

[0055] "Essentially" in this context means that at least 95 mol%, preferably at least 98 mol%, particularly preferably at least 99 mol%, more preferably at least 99.5 mol%, even more preferably at least 99.8 mol%, and most preferably 100 mol% of the total amount of polyols of component A) consist of linear polyols.

[0056] The hardness of thermoplastic polyurethanes can be adjusted from 45 Shore D to 95 Shore D by selecting the molar ratio of component (A) to component (C).

[0057] The amounts of the reaction components for the NCO-functional prepolymer formation in step 1) are chosen such that the NCO / OH ratio of polyisocyanate to polyol in step 1) is 1.1:1 to 5.0:1.

[0058] The components are thoroughly mixed and the NCO prepolymer reaction in step 1) is preferably brought to complete conversion (with respect to the polyol component).

[0059] Subsequently, at least component (C) is mixed in as a chain extender (step 2) to form an essentially OH-functional prepolymer.

[0060] Then, in step 3), the remaining amount of component (B) is added, maintaining an NCO / OH ratio of 0.9:1 to 1.2:1. Preferably, the same component (B) is used in step 3) as in step 1).

[0061] Preferably, in process step 2), the molar ratio of NCO-functional prepolymer to component (C) is less than 1.0. Component (C) is therefore present in molar excess.

[0062] All linear polyols known to those skilled in the art and having an average molecular weight greater than 500 g / mol are suitable as component (A). In particular, the following linear polyols are suitable as component (A): a) polyester polyols, b) polyether polyols, c) polyether esters, d) polycarbonate polyols, e) polyether carbonates or mixtures of at least two of the polyols a) to e).

[0063] Suitable polyester diols a) can be prepared, for example, from dicarboxylic acids with 2 to 12 carbon atoms, preferably 2 to 6 carbon atoms, and polyhydric alcohols. Examples of suitable dicarboxylic acids include: aliphatic dicarboxylic acids such as succinic acid, glutaric acid, adipic acid, cortic acid, azelaic acid, and sebacic acid; dodecanedioic acid; and aromatic dicarboxylic acids such as phthalic acid, isophthalic acid, and terephthalic acid. The dicarboxylic acids can be used individually or as mixtures, e.g., in the form of a mixture of succinic, glutaric, and adipic acid. For the preparation of the polyester polyols, it may be advantageous to use the corresponding dicarboxylic acid derivatives, such as carboxylic acid diesters with 1 to 4 carbon atoms in the alcohol residue, carboxylic acid anhydrides, or carboxylic acid chlorides, instead of the dicarboxylic acids themselves.Examples of polyhydric alcohols are glycols with 2 to 12, preferably 2 to 6, carbon atoms, such as ethylene glycol, diethylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,10-decanediol, 1,12-dodecanediol, 2,2-dimethyl-1,3-propanediol, 1,3-propanediol, 1,2-propanediol, and dipropylene glycol. Depending on the desired properties, the polyhydric alcohols can be used alone or, optionally, in mixtures with each other. Also suitable are condensation products of hydroxycarboxylic acids, for example, hydroxycaproic acid, and polymerization products of lactones, for example, optionally substituted caprolactones. Preferably used polyester polyols are ethanediol polyadipates, 1,4-butanediol polyadipates, 1,6-hexanediol polyadipates, ethanediol-1,4-butanediol polyadipates, 1,6-hexanediol neopentylglycol polyadipates, 1,6-hexanediol-1,4-butanediol polyadipates and polycaprolactones.The polyester diols have molecular weights in the range of 500 to 5000 g / mol, preferably in the range of 600 to 3500 g / mol, and particularly preferably in the range of 800 to 3000 g / mol. They can be used individually or in mixtures with each other.

[0064] Suitable polyetherdiols (b) can be prepared by reacting one or more alkylene oxides with 2 to 4 carbon atoms in the alkylene residue with a starter molecule containing two bonded active hydrogen atoms. Examples of alkylene oxides include ethylene oxide, 1,2-propylene oxide, epichlorohydrin, 1,2-butylene oxide, and 2,3-butylene oxide. Preferably, ethylene oxide, propylene oxide, and mixtures of 1,2-propylene oxide and ethylene oxide are used. The alkylene oxides can be used individually, alternately, or as mixtures. Suitable starter molecules include, for example, water, amino alcohols such as N-alkyldiethanolamines (e.g., N-methyldiethanolamine), and diols such as ethylene glycol, 1,3-propylene glycol, 1,4-butanediol, and 1,6-hexanediol. Mixtures of starter molecules can also be used if desired. Suitable polyether diols also include the hydroxyl group-containing polymerization products of tetrahydrofuran.Trifunctional polyethers can also be used in proportions of 0 to 30 wt%, based on the bifunctional polyethers, but only in such quantities as to produce a thermoplastically processable product. Suitable polyether diols have a number-average molecular weight Mn of 500 to 5000 g / mol, preferably 750 to 5000 g / mol, and most preferably 900 to 4200 g / mol. They can be used individually or in mixtures with each other.

[0065] Suitable polyether esters (c) can be prepared, for example, by reacting short-chain polyether diols, such as polytetrahydrofurans with molecular weights of 250 to 1000 g / mol, with organic dicarboxylic acids, such as succinic acid or adipic acid. The polyether ester diols have molecular weights of 600 to 5000 g / mol, preferably 700 to 4000 g / mol, and particularly preferably 800 to 3000 g / mol. They can be used individually or in mixtures with each other.

[0066] Suitable polycarbonate diols d) can, for example, be prepared by reacting short-chain diols, such as 1,4-butanediol or 1,6-hexanediol, with diphenyl carbonate or dimethyl carbonate using catalysts and eliminating phenol or methanol. The polycarbonate diols have a number-average molecular weight of 500 to 5000 g / mol, preferably 750 to 5000 g / mol, and particularly preferably 1000 to 4500 g / mol.

[0067] Suitable polyether carbonate diols e) can be prepared, for example, by reacting short-chain polyether diols, such as polytetrahydrofurans with molecular weights of 250 to 1000 g / mol, with diphenyl or dimethyl carbonate using catalysts and eliminating phenol or methanol. Furthermore, polyether carbonate diols can be prepared by copolymerization of alkylene oxides, such as ethylene oxide or propylene oxide, or mixtures thereof, with carbon dioxide using suitable catalysts, such as double metal cyanide catalysts. The polyether carbonate diols have a number-average molecular weight of 500 to 8000 g / mol, preferably 750 to 6000 g / mol, and particularly preferably 1000 to 4500 g / mol.

[0068] Preferred organic polyisocyanates of component (B) used in steps 1) and 3) are aliphatic, cycloaliphatic, araliphatic, heterocyclic and aromatic polyisocyanates as described in Justus Liebig's Annalen der Chemie, 562, pp. 75-136.

[0069] Examples include: aliphatic diisocyanates, such as 1,6-hexamethylene diisocyanate; cycloaliphatic diisocyanates, such as isophorone diisocyanate, 1,4-cyclohexane diisocyanate, 1-methyl-2,4-cyclohexane diisocyanate, and 1-methyl-2,6-cyclohexane diisocyanate, as well as the corresponding isomer mixtures; 4,4'-dicyclohexylmethane diisocyanate, 2,4'-dicyclohexylmethane diisocyanate, and 2,2'-dicyclohexylmethane diisocyanate, as well as the corresponding isomer mixtures; aromatic diisocyanates, such as 2,4-toluene diisocyanate, mixtures of 2,4-toluene diisocyanate and 2,6-toluene diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, and 2,2'-diphenylmethane diisocyanate; and mixtures of... 2,4'-Diphenylmethane diisocyanate and 4,4'-Diphenylmethane diisocyanate, urethane-modified liquid 4,4'-Diphenylmethane diisocyanates and 2,4'-Diphenylmethane diisocyanates, 4,4'-Diisocyanatodiphenylethane-(1,2) and 1,5-Naphthylene diisocyanate.Preferably used are 1,6-hexamethylene diisocyanate, isophorone diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, diphenylmethane diisocyanate isomer mixtures with a 4,4'-diphenylmethane diisocyanate content of >96 wt.%, and in particular 4,4'-diphenylmethane diisocyanate and 1,5-naphthylene diisocyanate. The aforementioned diisocyanates can be used individually or in mixtures with each other. They can also be used together with up to 15 wt.% (calculated on the total amount of diisocyanate) of a polyisocyanate, for example, triphenylmethane-4,4',4"-triisocyanate or polyphenyl-polymethylene-polyisocyanate.

[0070] Preferably, component (B) is a mixture of diphenylmethane diisocyanate isomers with a 4,4'-diphenylmethane diisocyanate content of greater than 96 wt.% based on the total weight of component (B), preferably component (B) is 4,4'-diphenylmethane diisocyanate.

[0071] Preferably, 1,6-hexamethylene diisocyanate is used as component (B).

[0072] Suitable components (C) (chain extender) include all linear diols known to those skilled in the art with a molecular weight of 62 g / mol to 500 g / mol. The diols and / or their precursor compounds may be derived from fossil or biological sources. Preferably suitable diols are aliphatic diols with 2 to 14 carbon atoms, such as ethanediol, 1,4-butanediol, 1,6-hexanediol, 1,8-octanediol, 1,10-decanediol, 1,12-dodecanediol, diethylene glycol, and dipropylene glycol. However, suitable options also include diesters of terephthalic acid with glycols having 2 to 4 carbon atoms, such as terephthalic acid bis-ethylene glycol or terephthalic acid bis-1,4-butanediol, hydroxyalkylene ethers of hydroquinone, such as 1,4-di-(hydroxyethyl)hydroquinone, and ethoxylated bisphenols. Particularly preferred short-chain diols are ethanediol, 1,4-butanediol, 1,6-hexanediol, and 1,4-di-(hydroxyethyl)hydroquinone. Mixtures of the aforementioned chain extenders can also be used.In addition, small amounts of diamines and / or triols may be added.

[0073] Preferably, one or more diols selected from the group consisting of 1,2-ethanediol, 1,4-butanediol, 1,6-hexanediol, 1,4-di-(beta-hydroxyethyl)hydroquinone or a mixture of at least two of these are used as component (C), preferably 1,2-ethanediol, 1,4-butanediol or mixtures thereof are used as component (C) and 1,2-ethanediol is particularly preferably used as component (C).

[0074] The catalysts (D) used can be those commonly known from polyurethane chemistry. Suitable catalysts are well-known and common tertiary amines, such as triethylamine, dimethylcyclohexylamine, N-methylmorpholine, N,N'-dimethylpiperazine, 2-(dimethylaminoethoxy)ethanol, diazabicyclo[2,2,2]octane, and similar compounds, as well as, in particular, organic metal compounds such as titanium dioxide esters, iron compounds, bismuth compounds, tin compounds, e.g., tin diacetate, tin dioctoate, tin dilaurate, or the tin dialkyl salts of aliphatic carboxylic acids such as dibutyltin diacetate, dibutyltin dilaurate, or similar compounds. Preferred catalysts are organic metal compounds, especially titanium dioxide esters, iron compounds, or tin compounds. Dibutyltin dilaurate, tin dioctoate, and titanium dioxide esters are particularly preferred.

[0075] Further details and preferred embodiments of the manufacturing process for suitable TPUs can be found in EP 3 838 961 A.

[0076] Preferably, the TPE comprises a thermoplastic polyurethane (TPU), preferably produced according to the previously described process, in a range of 10 to 100 wt.%, more preferably in a range of 20 to 95 wt.%, more preferably in a range of 30 to 90 wt.%, and particularly preferably in a range of 40 to 85 wt.%, based on the total weight of the TPE.

[0077] Preferably, the polymer film A1) comprises a TPU with a Shore D hardness in the range of 45 to 85 Shore D, more preferably in the range of 50 to 80 Shore D, and most preferably in the range of 55 to 70 Shore D. The polymer film A1) preferably comprises the TPU, preferably produced according to the previously described process, in a range of 10 to 100 wt.%, and more preferably in a range of 20 to 95 wt.%, based on the total weight of the polymer film A1).

[0078] Preferably, the polymer film A2) comprises a TPU with a hardness in the range of 55 to 95 Shore D, more preferably in the range of 65 to 90 Shore D, and most preferably in the range of 70 to 85 Shore D. The polymer film A2) preferably comprises the TPU, preferably produced according to the previously described process, in a range of 10 to 100 wt.%, more preferably in a range of 20 to 95 wt.%, based on the total weight of the polymer film A2).

[0079] Examples of TPU types suitable for both polymer film A1) and polymer film A2) are: Estane®< from Lubrizol, Elastollan®< from BASF AG (Germany), Desmopan®< from Covestro Deutschland AG (Germany), preferably those with a hardness of 45 to 95 Shore D.

[0080] The thermoplastic polycarbonate (PC) can be any elastomeric PC that a person skilled in the art would select for this purpose. Preferably, the PC is manufactured according to the polycarbonates described in WO 2018 / 11436 A1, in particular the polycarbonate blends as described on page 3, last paragraph, to page 16, third paragraph.

[0081] The Polyethylene terephthalate (PET) Any PET that a person skilled in the art would use for the safety document A) according to the invention can be used. Preferably, the PET is a polyethylene terephthalate glycol (PETG), for example Eastar® from EASTMAN Chemical GmbH (Germany).

[0082] The thermoplastic styrene block copolymers (TPS)Any styrene block copolymer that a person skilled in the art would use for the safety document A) according to the invention can be used. Preferred TPS are styrene-ethylene-butylene-styrene block copolymer (SEBS), styrene-ethylene / propylene-styrene block copolymer (SEPS), styrene-isoprene-styrene block copolymer (SIS), styrene-ethylene-ethylene-butadiene-styrene (SEEPS), and methyl methacrylate-butadiene-styrene (MBS). Examples of SBS types are Styroflex® from BASF AG (Germany) and Thermolast® from Kraiburg Holding (Germany). Examples of SBES types are Saxomer® TPE-S from PCW GmbH (Germany), preferably those with a hardness of 45 to 95 Shore D.

[0083] The TPE preferably contains additives commonly used in plastics. Common additives include, for example, lubricants such as fatty acid esters, their metal soaps, fatty acid amides and silicone compounds, antiblocking agents, inhibitors, stabilizers against hydrolysis, light, heat and discoloration, flame retardants, dyes, pigments, inorganic or organic fillers and reinforcing agents. Further details on the aforementioned auxiliary and additive substances can be found in the relevant literature, for example, J.H. Saunders, K.C. Frisch: "High Polymers", Volume XVI, Polyurethanes, Parts 1 and 2, Interscience Publishers 1962 and 1964 respectively, R. Gächter, H. Müller (Ed.): Taschenbuch der Kunststoff-Additive, 3rd edition, Hanser Verlag, Munich 1989, or DE-A 29 01 774.

[0084] Preferably, the outer surfaces AS1) and AS2) of the security document A) consist of a polymer film A1), A2) or A3), which contains or consists of a TPU.

[0085] Preferably, at least one of the polymer films of the security document A) selected from the group consisting of the first polymer film A1), the second polymer film A2), or both, contains the TPE in an amount in the range of 50 to 100 wt.%, preferably 60 to 90 wt.%, and particularly preferably 70 to 80 wt.%, based on the total weight of the respective polymer film A1) or A2). Particularly preferably, polymer film A1) consists of a TPE. Particularly preferably, polymer film A2) consists of a TPE.

[0086] Preferably, at least one of the polymer films of the security document A) selected from the group consisting of the first polymer film A1), the second polymer film A2) or both polymer films A1) and A2), comprises a polymer selected from the group consisting of a thermoplastic polyurethane (TPU), a copolyester or a mixture of at least two thereof or mixtures of TPU and other TPEs in an amount in the range of 50 to 100 wt.%, preferably 60 to 90 wt.%, particularly preferably 70 to 80 wt.%, based on the total weight of the respective polymer film A1) or A2).

[0087] The security feature A4), formed by laser engraving in the form of a watermark, can be introduced into the polymer film A2) in any way a person skilled in the art would choose for this purpose using a laser. Preferably, the watermark is introduced into the polymer film A2) by irradiating the security document A) with a laser from at least one outer surface AS1) or AS2).

[0088] Preferably, the laser is an IR marking laser, such as a diode laser, in particular an Nd:YAG laser, which emits mainly at 1064 nm. The peak pulse power of the laser is preferably in the range of 40 to 60 kW, more preferably from 42 to 50 kW.

[0089] Preferably, the security document A) does not contain a laser marking additive, at least in the areas where the watermark is located, except in the polymer film A2). Preferably, the polymer films A1) and optionally A3) contain a laser marking additive in an amount of 0 wt.% to ≤ 0.5 wt.%, more preferably ≥ 0.01 wt.% to ≤ 0.2 wt.%, and particularly preferably ≥ 0.05 wt.% to ≤ 0.3 wt.%, based on the total mass of the polymer film A1) or A3).

[0090] Preferably, the security document A) comprises an arrangement of polymer films A1), A2) and optionally at least one polymer film A3) selected from the group consisting of A1) - A2), A1) - A2) - A3), A3) - A1) - A2) - A3), preferably A1) - A2) - A3). Here, the polymer film A1) preferably has a thickness in the range of 20 to 100 µm, particularly preferably 30 to 50 µm, the polymer film A2) preferably has a thickness in the range of 10 to 150 µm, particularly preferably 20 to 60 µm, and the polymer film A3) preferably has a thickness in the range of 20 to 100 µm, particularly preferably 30 to 50 µm.

[0091] In a preferred embodiment of the security document A), the polymer film A2) contains a laser marking additive preferably in an amount of ≥ 0.1 wt.% to ≤ 6 wt.%, more preferably ≥ 0.2 wt.% to ≤ 5 wt.%, and particularly preferably ≥ 0.5 wt.% to ≤ 4 wt.%, based on the total mass of the polymer film A2). The laser marking additive is preferably an additive that, upon interaction with laser light of a wavelength in the range of 300 nm to 1600 nm, more preferably 500 to 1200 nm, and particularly preferably 700 to 1100 nm, enables a dark discoloration of the polymer material, especially the TPU. Preferably, the security document (A) comprises a metal oxide or a metal silicate as the laser marking additive in the polymer film A2).Preferably, the security document A) comprises a metal oxide, a metal phosphate, or a metal silicate of B, Cu, Ni, Zn, Al, Zr, Si, Sn, Bi, W, Mo, Cr, Mg, Mn, Ce, Ti, and Ba, in particular a copper(II) phosphate in the form of a copper hydroxide phosphate, in the polymer film A2) in an amount in the range of 0.1 to 10 wt.%, more preferably in the range of 0.2 to 8 wt.%, and particularly preferably in the range of 0.5 to 5 wt.%, based on the total weight of the polymer film A2). If areas of the security document A) are subsequently processed with a laser, the watermarks can be introduced due to the additive content in the polymer film A2) without being able to be non-destructively altered in the security document A).

[0092] Preferably, the security document A) therefore has a further polymer film on both sides of the polymer film A2). Preferably, one side of the polymer film A2) is covered by the polymer film A1), while the other side of the polymer film A2) is covered by the polymer film A3).

[0093] To adjust the transparency and translucency of the security document A), various filler materials, in particular pigments, can be used. Preferably, both the polymer film A1) and the optional polymer film A3) have a pigment content in the range of 0.5 to 30 wt.%, more preferably in the range of 1 to 25 wt.%, and most preferably in the range of 5 to 20 wt.%, based on the total mass of the respective film A1), A2), or A3). The pigment is preferably titanium dioxide. The addition of the pigment makes the outer layers of the security document A) particularly translucent, so that the watermark in the polymer film A2) is only visible in transmitted light from both sides.

[0094] In a preferred embodiment of the security document A), the TPE of the first polymer film A1) and / or the second polymer film A2) is a thermoplastic polyurethane. Preferably, the TPU of the polymer film A1) and / or the second polymer film A2) has a hardness in the range of 45 Shore D to 95 Shore D, particularly preferably from 50 Shore D to 85 Shore D.

[0095] Preferably, the polymer films A1) and optionally A3), in particular those located on the outer sides AS1) and AS2) of the security document A), comprise a TPE with a hardness in the range of 45 Shore D to 85 Shore D, preferably in the range of 50 Shore D to 80 Shore D, most preferably from 55 Shore D to 70 Shore D.

[0096] Preferably, the at least one polymer film A2), which is preferably in direct contact with one of the polymer films A1) or A3), comprises a TPE with a hardness in the range of 55 Shore D to 95 Shore D, preferably in the range of 65 Shore D to 90 Shore D, most preferably from 70 Shore D to 85 Shore D.

[0097] In a preferred embodiment of safety document A), the TPE is selected from the group consisting of a thermoplastic polyamide elastomer, an olefin-based thermoplastic elastomer, preferably PP / EPDM, a thermoplastic styrene block copolymer such as SBS, SEBS, SEPS, SEEPS and MBS, a thermoplastic polyurethane TPU, a copolyester elastomer, a polyether block amide, a copolyester, a polycarbonate, a polyethylene terephthalate PET, a polyethylene terephthalate glycol PETG or a mixture of at least two thereof. Preferably, the TPE is a thermoplastic polyurethane.

[0098] In a preferred embodiment of security document A), the outer surfaces AS1) and AS2) of security document A) are a polymer film A1), A2) or A3), which includes or consists of a TPU. Preferably, both polymer film A1) and polymer film A2) and optionally also polymer film A3) comprise a TPU. Most preferably, both polymer film A1) and / or polymer film A2) and optionally polymer film A3) consist of a TPU.

[0099] In a preferred embodiment of the security document A), at least all polymer films A1), A2), and optionally A3) consist exclusively of polymers, in particular thermoplastic polyurethanes (TPU). Preferably, the entire security document A) consists of polymers, in particular thermoplastic polyurethanes, excluding the optional particles A5). Preferably, the TPU used for the polymer films A1), A2), and optionally A3) has a hardness in the range of 40 to 95 Shore D, particularly preferably 50 to 90 Shore D, and most preferably 60 to 80 Shore D.

[0100] In a preferred embodiment of the security document A), the security document A) comprises at least one further polymer film A3), wherein the at least one further polymer film A3) contains the TPE, in particular the TPU, in an amount in the range of 50 to 100 wt.%, preferably 60 to 90 wt.%, particularly preferably 70 to 80 wt.%, based on the total weight of the respective polymer film A3).

[0101] Particularly preferably, the at least one further polymer film A3) consists of a TPE. Most preferably, the at least one polymer film A3) consists of a TPU.

[0102] Preferably, the at least one further polymer film A3) has the same composition as the polymer film A1) or A2). Most preferably, all three polymer films A1), A2), and A3) contain a TPE by at least 50 wt.%, preferably by at least 80 wt.%, and most preferably by 100 wt.%, wherein the TPE is preferably one of the aforementioned TPEs, and most preferably at least one TPU. Most preferably, the further polymer film A3) has the same composition as the first polymer film A1).

[0103] In a preferred embodiment of the security document A), at least one of the polymer films selected from the group consisting of the first polymer film A1), the second polymer film A2) or both polymer films A1) and A2) includes the TPE, preferably a TPU, in an amount in the range of 50 to 100 wt.%, preferably 60 to 90 wt.%, particularly preferably 70 to 80 wt.%, based on the total weight of the respective polymer film A1) or A2).

[0104] In a preferred embodiment of the security document A), at least one of the polymer films selected from the group consisting of the first polymer film A1), the second polymer film A2), or both, comprises a polymer selected from the group consisting of a thermoplastic polyurethane TPU, a copolyester, or a mixture of at least two thereof, or mixtures of TPU and other TPEs, in an amount in the range of 50 to 100 wt.%, preferably 60 to 90 wt.%, particularly preferably 70 to 80 wt.%, based on the total weight of the respective polymer film A1) or A2). Preferably, at least the polymer film A1) comprises or consists of a thermoplastic polyurethane in an amount in the range of 50 to 100 wt.%, preferably 60 to 90 wt.%, particularly preferably 70 to 80 wt.%, based on the total weight of the respective polymer film A1).Preferably, at least the polymer film A2) comprises or consists of a thermoplastic polyurethane in an amount in the range of 50 to 100 wt.%, preferably 60 to 90 wt.%, particularly preferably 70 to 80 wt.%, based on the total weight of the respective polymer film A2).

[0105] In a preferred embodiment of the security document A), the security document A) comprises a further security feature A6), selected from the group consisting of a hologram, a print, a security thread, a fluorescent fiber, particles, a dye, a security pigment, carbon black, metallic or non-metallic micro- or nanoparticles, magnetic particles, an embossing or a combination of at least two thereof.

[0106] In a preferred embodiment of security document A), security document A) has at least one of the following properties: a. A tear strength in the range of 50 N / mm² to 400 N / mm² determined according to DIN 53363:2003-10; b. a tensile strength in the range of 20 MPa to 200 MPa determined according to ISO 527-3:1995; c. a light transmission in the range of 0% to 85%, determined according to ISO 13468-2:2019; d. a security pigment content in the range of 0.1 to 10 wt.%, based on the total weight of the security document A; e. a crease recovery angle in the range of 120° to 170°, more preferably 130° to 160°, particularly preferably 140° to 150° according to DIN 53 890 / 91; f. a Vicat softening temperature of 60°C to 105°C, particularly preferably of 65°C to 85°C according to DIN EN ISO 306:2023-03; g. a nominal elongation at break in a range of at least 60%, preferably of 60 to 800%, measured according to DIN EN ISO 527-1:2012.

[0107] Another aspect of the invention relates to a method for producing a security document A) with a first outer surface AS1) and a second outer surface AS2) opposite the first outer surface AS1), comprising the steps: i) Providing a first polymer A1'); ii) Providing a second polymer A2') containing at least one IR absorber; iii) Optionally providing a further polymer A3'), which is preferably the same as the first polymer A1'); iv) Melting the polymers from step i), ii) and optionally iii); v) Either combining the polymer melts from step iv) to form a first polymer film A1) from the first polymer A1'), a second polymer film A2) from the second polymer A2') and optionally a further polymer film (A3) from the first polymer A1') or from the further polymer A3') as a co-extrudate, or forming a laminate from separate polymer films A1), A2), and optionally A3), which were formed from the melts in step iv); vi) Incorporating a security feature A4) in the form of a watermark into the second polymer film A2) by means of laser engraving, while retaining the security document A);vii) Optionally joining, preferably by ultrasonic welding, vibration welding or laser welding, a polymer layer A7) to one of the outer layers AS1) or AS2) over an area of ​​at least 1 mm² ; wherein the outer surfaces AS1) and AS2) are formed by one of the polymer films A1), A2) or A3), each containing or consisting of a TPE, preferably a TPU, and at least one of the polymer films A1), A2) and / or A3) is translucent.

[0108] Preferably, the polymer layer A7) also comprises a polymer, preferably a TPE, more preferably a TPU, as previously described for polymer films A1), A2) and optionally A3). Preferably, the polymer layer A7) comprises the TPE, in particular the TPU, in an amount in the range of 50 to 100 wt.%, more preferably 70 to 95 wt.%, and particularly preferably 80 to 90 wt.%.

[0109] Preferably, the security document A) produced in this way has all compositions, properties and structures, in particular of the polymer films A1), A2) and optionally A3), as previously described for the security document A) according to the invention.

[0110] The provision of the first polymer A1') in step i), the second polymer A2') in step ii) and / or optionally the further polymer A3') in step iii) can be carried out by any method known to those skilled in the art. Preferably, the provision in step i), ii) and / or iii) is carried out by introducing granules of the respective polymer into an extruder or other device in which the polymer can subsequently be melted.

[0111] In step iv), the polymers from steps i), ii), and optionally iii) are preferably melted by heating the extruder with the extruder screw running. In step v), the polymer melts from step iv) are combined. This is preferably done using a suitable die. Alternatively, the melts from step iv) can also be fed sequentially onto a substrate. The melts in step v) are preferably co-extruded through a die or formed into individual polymer films by casting. Preferably, the melts are extruded in step v).

[0112] If the melts are formed separately to form the polymer films A1), A2), or A3), they are preferably joined together by lamination to form the security document A) as a laminate. If the melts are extruded together in step v) using a die, the security document A) is produced as an extruded film or co-extruded film after the melts have cooled. The viscosity of the melts is preferably in a range suitable for polymer processing, especially for flat film production, between 20 and 2000 Pa s, preferably in the range of 50 to 1000 Pa s, and particularly preferably in the range of 75 to 500 Pa s. It is immaterial whether the polymer melt is a polymer with a defined melting point Tm or a defined melting interval Tm ± ΔT, or whether it is a polymer without a defined melting point.In extrusion, it is preferred, especially at the point of exit from the die, that the polymer is heated to such an extent above the melting point Tm or the glass transition point Tg that the viscosity of the polymer is reduced to such an extent that processing into a polymer film is possible.

[0113] During the extrusion of the melts in step v), at least one additional film is preferably introduced between the individual melts as a security feature (A4') in step vi). The at least one introduced film preferably has a thickness in the range of 5 to 35 µm, more preferably 7 to 25 µm, and particularly preferably 10 to 20 µm. This at least one additional film can be introduced across the entire width of the melts in step v) or only across a section of the melts. Preferably, the at least one additional film has a width that corresponds to 30 to 100%, more preferably 40 to 90%, and particularly preferably 50 to 80% of the width of the melt. The at least one additional film can serve to introduce the security feature (A4').

[0114] After the polymer melts of polymers (A1'), (A2') and optionally (A3') are extruded through the die to form a film, the extruded film is preferably guided onto two rollers. Preferably, one or both rollers have a ductile surface. This allows for a more homogeneous pressure distribution across the entire width of the extrudate. This can be particularly advantageous if the thin film fed into the roller gap, which serves as a security feature (A4'), has cutouts or printed symbols, preferably with a color layer thickness of up to 20 µm, in which the pressure across the rollers can vary due to missing or excess material. Ductile rollers can compensate for this pressure difference, resulting in improved adhesion even in these areas. Such rollers are, for example, PTFE-coated or PTFE-encased rubber rollers or silicone-coated rollers.

[0115] In step vi), a security feature A4) in the form of a watermark is incorporated into the resulting security document A) by means of laser engraving. This is done, in particular, into the polymer film A2). Any laser suitable for engraving the polymer film A2) can be used. Preferably, the laser is an IR laser, especially an IR marking laser. The laser is preferably operated with a peak pulse power in the range of 10 kW to 100 kW. A pulse rate of 10 ps to 1000 ns is preferably used.

[0116] Depending on whether it is a two-layer or a three-layer or multi-layer security document A), the extruded film, consisting of at least the polymer films A1) and A2), is irradiated with a laser from the side of polymer film A1) or A2). If it is a two-layer security document A), both polymer films A1) and A2) can be translucent, or only one of the two polymer films A1) or A2), depending on whether it is desired that the security feature A4) be visible from both sides of the security document A) only in transmitted light and not in direct light, or only from one side of the security document A).

[0117] To introduce the security feature A4) into the polymer film A2), the composite of polymer films A1) and A2) is irradiated from the side of polymer film A1) using a laser beam, and the watermark is introduced into polymer film A2). This directly alters the color of the polymer in polymer film A2) at the interface between polymer films A1) and A2), preferably blackening it. Depending on the concentration of laser marking additive and the thickness of polymer film A1), the watermark can be lighter or darker.

[0118] If it is a three-layer or multi-layer security document A), the security feature A4) can be introduced either through the polymer film A1) or A3) by means of a laser beam into the polymer film A2), which is located between the two.

[0119] If the security document A) is to contain a watermark as a security feature A4) that is visible from both sides of the security document A) only when illuminated by transmitted light, then at least two of the at least three polymer films A1), A2), and A3) should be translucent. If the security feature A4) is applied through polymer film A1), then preferably polymer film A1) and one of the polymer films A2) and / or A3) are translucent. All other polymer films A3) may be transparent. If the security feature A4) is applied by irradiating the security document A) with a laser through polymer film A3), then preferably polymer film A3) and one of the two polymer films A2) or A1) are translucent. All other polymer films A3) may be transparent. Preferably, both polymer film A1) and polymer film A3) are translucent.

[0120] Preferably, the security document A) comprises an arrangement of polymer films selected from the group consisting of A1) - A2), A1) - A2) - A3), A3) - A1) - A2) - A3), preferably A1) - A2) - A3). Here, the polymer film A1) preferably has a thickness in the range of 20 to 100 µm, particularly preferably 30 to 50 µm, the polymer film A2) preferably has a thickness in the range of 10 to 150 µm, particularly preferably 20 to 60 µm, and the polymer film A3) preferably has a thickness in the range of 20 to 100 µm, particularly preferably 30 to 50 µm.

[0121] As mentioned above, the resulting security document A) can incorporate further security features A4') or combinations of security features A4'). Preferred examples include: sintered fibers, planchettes, metal fibers, marking agents, IR or UV dyes, security pigments, fluorescent dyes, effect pigments, or security threads, wherein these security features A4) are added to the polymer mixture, which is present as granules, in step i) or to the melt in step iv), or are sprinkled near the roll gap or blown onto the melt flap in step v), or, in the case of a security thread or security film, are guided into the roll gap. It is also possible to incorporate a security feature A4) into the thin film supplied.Thus, the security features already known from the field of paper banknotes can be used without further modification, as described in DE 6 98 33 653 T2, in particular in claim 1, or in CH 704 788 A1 on page 7. Security features known from paper documents include, for example: security thread, OVD, melange fibers, security pigments, iridescent color applications, chips, in particular RFID chips, and magnetic stripes.

[0122] Alternatively, it is preferable to use an engraving roller as one of the rollers.

[0123] The extrusion is preferably carried out using a simple melt of a fully reacted polymer. Alternatively, it may be preferred to use a prepolymer, as described in CH 704 788 A1, as a starting material for the formation of one of the polymer films A1), A2), or optionally A3). The prepolymer is preferably added before or after the roll gap to a further melt of a polymer that forms one of the other polymer films A1), A2), or optionally A3). The prepolymer is then chemically or physically cured and / or reacted and / or gelled. Furthermore, the present invention relates to a multilayer substrate such as can be produced in a process described above, or as is actually produced by a process as described above.

[0124] Preferably, a line pressure in the range of 0 to 500 N / cm, more preferably 250 to 450 N / cm, is applied between the roller pair immediately after the introduction of the melt. The roller pair is preferably maintained at a temperature above room temperature, preferably in the range of 10 to 180 °C, more preferably 20 to 120 °C, and particularly preferably 25 to 100 °C. Ideally, the roller temperature should not exceed the melting temperature or the glass transition point of the materials used in the resulting polymer films A1), A2), or optionally A3). Preferably, the roller temperature is kept slightly below the glass transition point Tg and / or the melting point Tm of the lowest-melting polymer. If the polymers used in the melt in step v) are fully reacted, the roller temperatures can also be slightly above the melting temperature or the glass transition point.

[0125] Optionally, particles A5) can be introduced into one of the polymer melts A1'), A2') or optionally A3'). The type, quantities and properties of particles A5) have already been described for the safety document A) according to the invention and also apply to the process according to the invention.

[0126] The optional joining of the additional polymer layer A7) to one of the outer layers AS1) or AS2) in step vii) over an area of ​​at least 1 mm² can be carried out using any joining method known to those skilled in the art for joining polymer films. Preferably, the joining method is ultrasonic welding, vibration welding, laser welding, or a combination of at least two of these. The polymer layer A6) is, for example, the data page of a passport.

[0127] The design of the polymer films A1), A2) and optionally A3) corresponds to the polymer films as specified in connection with the safety document A) according to the invention. In particular, the compositions, thicknesses, lengths and widths, as well as the shape and properties, are the same as previously described for the polymer films A1), A2) and optionally A3).

[0128] Preferably, all polymer films A1), A2) and A3) consist exclusively of polymers. Preferably, the complete security document A), excluding the security feature A4) and optionally the particles A5), consists of at least 90 wt.%, preferably at least 98 wt.%, more preferably at least 99 wt.%, and particularly preferably at least 100 wt.%, of polymers, based on the total weight of the security document A).

[0129] As already mentioned previously for Safety Document A) according to the invention, preferred materials for this purpose are, in particular, plastics from the group of thermoplastic elastomers, e.g., thermoplastic polyurethanes, copolyesters, polyether block amides, thermoplastic polyolefins, styrene block copolymers, and mixtures of at least two of the aforementioned polymers. Due to their chemical structure, these exhibit particularly good compatibility during extrusion, coextrusion, and the production of blends. Therefore, after their combination during extrusion, lamination, or coating, they are characterized by a particularly strong bond, resulting from both good material adhesion and good compatibility of the individual components. Further advantageous properties of a polymeric material for Safety Document A) according to the invention are high chemical resistance to acids, bases, solvents, bleaching agents, etc.High thermal resistance, UV resistance, high opacity, high flexural fatigue strength and high softening temperatures.

[0130] Laminated films produced by extrusion lamination are typically constructed such that the thin film to be laminated, e.g., film A1) made of polymer A1'), is guided on a roughened, tempered or cooled metal roller. The melt of the second polymer, e.g., A2'), is extruded from the slot die and forced against the first metal roller via a rubber-coated, roughened roller, thus pressing the polymer melt onto the incoming film. The structure of the roughened roller surfaces is transferred to both the molten polymer and the incoming film to be laminated. Cooling the tempered roller pair below the polymer's solidification temperature prevents the film from adhering to the rubber roller.Since the polymer A1'), A2'), or optionally A3') comes into direct contact with the supplied thin film A1), A2), or optionally A3) in molten form, the thermal effect on the supplied film is brief and therefore virtually harmless. Preferably, the polymer film, for example polymer film A1), is a TPU onto which the melt of a PC is applied. It is possible to work with comparatively high melt temperatures in the range of 200°C to 250°C. This has the advantage that the high temperature of the melt allows for a lower melt viscosity, resulting in a better and faster bonding of the plastic layers and enabling a more intimate bond as required for a security document A). At the same time, faster process speeds are permitted.

[0131] Preferably, the roller pair consists of temperature-controlled rollers with a matte surface that is transferred to the extruded layer composite to a specific level during extrusion. As an alternative to a roller pair consisting of one rubber and one metal roller, two metal rollers can also be used. Matte surfaces are primarily defined as those with a roughness in the range of 10 to 30 µm.

[0132] If two metal rollers are used, preferably one of the two metal rollers is designed with thin walls and pressurized internally with hydraulic pressure. This allows the metal roller to function like a rubber roller, as it can yield locally when thickening occurs, e.g., when printing with thick layers of ink.

[0133] Metal rollers with a highly polished surface produce films with correspondingly smooth surfaces. These films are not well suited for security printing because they tend to stick together and can only be printed at high speeds with considerable effort. Typically, these films are separated using ionized compressed air before being fed to the printing press. An alternative to polished rollers are rollers with only locally limited polished areas, which are later used, for example, in specific locations on the security document A), such as banknotes.

[0134] In the production of security document A) by co-extrusion of at least three polymer films A1), A2), and A3) in a symmetrical structure, for example, with an inner polymer film A2) of polymer A2') and an outer polymer film A1) or A3) of polymer A1') or A3'), respectively, wherein polymers A1') and A3') are particularly preferably identical, the softening temperature of the outer polymer A1') or A3') is preferably lower than that of the inner polymer A2'). Alternatively, the outer polymer A1') or A3') has a lower melt viscosity than the inner polymer A2') under the given processing conditions. In this way, the printability of the resulting security document A) can be optimized by appropriately selecting the outer polymer. Preferably, a polymer A2') is chosen for the inner polymer film A2) to optimize the film's mechanical properties.Preferably, such a multilayer polymer layer consists of largely compatible polymers, i.e., polymers that can be easily extruded together, such as thermoplastic polyurethanes (TPU), copolyesters, polyether block amides, thermoplastic polyolefins, styrene block copolymers and mixtures of at least two of these.

[0135] In a preferred embodiment of the method, the polymer film A2) contains a laser marking additive in an amount of ≥ 0.1 wt.% to ≤ 4.5 wt.%, preferably ≥ 0.2 wt.% to ≤ 4.0 wt.%, and particularly preferably ≥ 0.5 wt.% to ≤ 3.0 wt.%, based on the total mass of the polymer film A2). The laser marking additive is preferably selected from the group of additives described in connection with the safety document A) according to the invention. Preferably, the laser marking additive is introduced into the polymer A2') before being provided in step ii), preferably by melting the granules of the polymer A2') and compounding the laser marking additive into the polymer.

[0136] In a preferred embodiment of the process according to the invention, at least one of the polymers is selected from the group consisting of polymer A1'), polymer A2'), optionally polymer A3'), a polymer selected from the group consisting of a thermoplastic polyamide elastomer, a thermoplastic olefin-based elastomer, preferably PP / EPDM, a thermoplastic styrene block copolymer, a thermoplastic polyurethane TPU, a copolyester elastomer, a polyether block amide, a copolyester, a polycarbonate, a polyethylene terephthalate PET, a polyethylene terephthalate glycol PETG or a mixture of at least two thereof, preferably TPU.The preferred type and quantities of the TPE, in particular the TPU, and the remaining composition of the polymers A1'), polymers A2') and optionally polymers A3') and thus also of the polymer films A1), A2) and optionally A3) are the same as previously described for the safety document A) according to the invention.

[0137] Preferably the second polymer film A2) comprises a polymer selected from the group consisting of a TPE, a copolyester, a polyether block amide or a mixture of at least two thereof in an amount in the range of 50 to 100 wt.%, preferably 60 to 90 wt.%, particularly preferably 70 to 80 wt.%, based on the total weight of the polymer film A2).

[0138] Preferably, the first polymer film A1) and optionally A3) contains the TPE in an amount in the range of 50 to 100 wt.%, preferably 60 to 90 wt.%, particularly preferably 70 to 80 wt.%, based on the total weight of the polymer film A1).

[0139] Another object of the invention relates to the use of the security document A) according to the invention or the security document A) produced according to the method according to the invention in or as a banknote, birth certificate, postage stamp, tax stamp, visa pages of a passport, hinge for the data page of a passport or as a carrier layer of an electromagnetic shield in the passport. Experimental section Example 1) Production of a TPU masterbatch with 30% TiO2 . Master-Batch: Compounding of a highly concentrated TiO2 masterbatch

[0140] The masterbatches for the production of the polymer films A1) or A2) were produced using a conventional twin-screw compound extruder (ZSK 32) at processing temperatures typical for TPU of 190°C to 250°C. a) A master batch a) with the following composition was compounded and granulated: · 70 wt% Desmopan™< 9365D from Covestro Deutschland AG, Germany · 30 wt% TiO₂ Kronos 2260 from Kronos Titan GmbH, Germany. b) A master batch b) with the following composition was compounded and granulated: · 70 wt% Desmopan™< 9385D from Covestro Deutschland AG (Germany) · 30 wt% TiO₂ Kronos®< 2260 from Kronos Titan GmbH, Germany Other TPU masterbatch used (c), sourced from the market:

[0141] c) A laser compound c) for TPU, from Avient Colorants Germany GmbH (Germany) designated GEA0025547, which contained 50 ± 5 wt% copper(II) phosphate in the form of a copper hydroxide phosphate as a laser marking additive in a thermoplastic polyurethane. The equipment used to produce the extruded or co-extruded film included:

[0142] • An extruder a) for single-layer films or two extruders a) and b) for co-extrusion of polymers A1') and A2') and optionally A3'), the extruders containing at least one screw with a diameter (D) of 60 mm and a length of 33 D, and the screws having a degassing zone; • a melt pump; • a deflection head; • a multilayer block; • a slot die with a width of 450 mm; • a three-roll calender with a horizontal roll arrangement, wherein the third roll is pivotable by + / - 45° from the horizontal; • a roller conveyor; • a thickness measuring device; • a device for applying protective film to both sides; • a take-off device; • a winding station. Example 2): 3-layer film, watermark visible only in transmitted light

[0143] Production of multilayer white TPU film with a thickness of 100 µm, featuring a laser-markable core layer of Shore 85D TPU and Shore 65D TPU in the outer layers of the extruded film, with a layer thickness ratio of 30 / 40 / 30 µm. Production of the extruded film:

[0144] The following materials were conveyed into the feed hopper a) of the extruder a), whereby the masterbatch a) from Example 1) and the Desmopan ™< 9365D from the dryer were conveyed: Polymer A1') 50 wt% Masterbatch a) 50 wt% Desmopan™< 9365D from Covestro Deutschland AG (Germany)

[0145] The material mixture from feed hopper a) was conveyed into extruder a). The material Desmopan™< 9385D and the masterbatch b) from Example 1) were filled into feed hopper b) of extruder b). The mixing ratio was set as follows: Polymer A2') 45 wt% Desmopan™ < 9385D from Covestro Deutschland AG (Germany) 45 wt% Master-Batch b) 10 wt% Master-Batch c)

[0146] The material mixture from the filling hopper b) was conveyed into the extruder b).

[0147] The film was extruded as in Example 2). The material from extruder a) formed the two outer layers (first polymer film A1) and A3)) with a thickness of 30 µm each, and the melt from extruder b) formed the middle layer in the form of the second (polymer film A2)) with a thickness of 40 µm. Example 3): 3-layer film with improved stiffness and dimensional stability, watermark visible only in transmitted light

[0148] Production of multilayer white TPU film with a thickness of 100 µm, featuring a laser-markable core layer of Shore 65D TPU and Shore 85D TPU in the outer layers of the extruded film, with a layer thickness ratio of 30 / 40 / 30 µm. Production of the extruded film:

[0149] The following materials were conveyed into the feed hopper a) of the extruder a), whereby the masterbatch a) from Example 1) and the Desmopan ™< 9365D from the dryer were conveyed: Polymer A1') 50 wt% Masterbatch a) 50 wt% Desmopan™< 9365D from Covestro Deutschland AG (Germany)

[0150] The material mixture from feed hopper a) was conveyed into extruder a). The material Desmopan™< 9385D and the masterbatch b) from Example 1) were filled into feed hopper b) of extruder b). The mixing ratio was set as follows: Polymer A2') 45 wt% Desmopan™ < 9385D from Covestro Deutschland AG (Germany) 45 wt% Master-Batch b) 10 wt% Master-Batch c)

[0151] The material mixture from the filling hopper b) was conveyed into the extruder b).

[0152] The film was extruded as in Example 2). The material from extruder a) formed the two outer layers, in the form of the first polymer film A1) and the second polymer film A3), each with a thickness of 30 µm, and the melt from extruder b) formed the middle layer in the form of the second polymer film A2), with a thickness of 40 µm. Example 4): 3-layer film with improved stiffness and dimensional stability, watermark visible only in transmitted light

[0153] Production of multilayer white TPU film with a thickness of 100 µm, featuring a laser-markable core layer of Shore 65D TPU and Shore 85D TPU in the outer layers of the extruded film, with a layer thickness ratio of 40 / 30 / 40 µm. Production of the extruded film:

[0154] The following materials were conveyed into the feed hopper a) of the extruder a), whereby the masterbatch a) from Example 1) and the Desmopan ™< 9365D from the dryer were conveyed: Polymer A1') 50 wt% Masterbatch a) 50 wt% Desmopan™< 9365D from Covestro Deutschland AG (Germany)

[0155] The material mixture from the filling hopper a) was conveyed into the extruder a).

[0156] The material Desmopan™< 9385D and the masterbatch b) from Example 1) were filled into the filling hopper b) of the extruder b). The mixing ratio was set as follows: Polymer A2') 45 wt% Desmopan™ < 9385D from Covestro Deutschland AG (Germany) 45 wt% Master-Batch b) 10 wt% Master-Batch c)

[0157] The material mixture from the filling hopper b) was conveyed into the extruder b).

[0158] The film was extruded as in Example 2). The material from extruder a) formed the two outer layers in the form of the first polymer film A1) with a thickness of 40 µm each, and the melt from extruder b) formed the middle layer in the form of the second polymer film A2) with a thickness of 30 µm. Example 5): Production of two-layer white TPU film Production of the extruded film:

[0159] The following materials were conveyed into the feed hopper a) of the extruder a), whereby the masterbatch a) from Example 1) and the Desmopan™< 9365D from the dryer were conveyed: Polymer (A1') 50 wt% masterbatch a) 50 wt% Desmopan™ 9365D from Covestro Deutschland AG (Germany)

[0160] The material mixture from the filling hopper a) was conveyed into the extruder a).

[0161] The material Desmopan™< 9385D and the masterbatch b) from Example 1) were filled into the filling hopper b) of the extruder b). The mixing ratio was set as follows: Polymer (A2') · 45% by weight DesmopanTM 9385D · 45% by weight master batch b) · 10% by weight master batch c)

[0162] The material mixture from the filling hopper b) was conveyed into the extruder b).

[0163] The film was extruded as in Example 2). The material from extruder a) formed the first outer layer in the form of the first polymer film A1) with a thickness of 45 µm, and the melt from extruder b) formed the second outer layer in the form of the polymer film A2) with a thickness of 45 µm.

[0164] The security feature A4) 100, in the form of a laser engraving, was applied in all examples 3) to 6) using an IR marking laser, specifically a diode IR laser emitting at a wavelength of 1064 nm and with a peak pulse power of 40 kW, a pulse duration of 8 ns at 20 kHz, and a pulse repetition frequency of 1 kHz to 100 kHz. Engraving was performed at 60% of this power, with an image resolution of 50 to 150 DPI. The laser beam 150 was directed through the polymer film A1) 110 onto the polymer film A2) 120, as shown in Figure 1 The process was demonstrated using an Nd:YAG laser, focused on the surface of polymer film A1, which was in contact with polymer film A2. A laser frequency of 30 kHz and a current of 28 amperes were set for engraving the watermark. The laser feed rate was 100 mm / s.

[0165] In Figure 2Steps 200 to 250 of the process according to the invention are shown, with step 200 summarizing the provision of the first polymer A1') in step i), the second polymer A2') in step ii), and optionally the further polymer A3') in step iii). Step 210 represents the melting of the polymers from steps i), ii), and iii) 200, and step 220 the combining of the polymer melts in step v) of the process according to the invention. The introduction of the security feature A4) in the form of a watermark 140 from step vi) is shown in step 230. Step 240 represents the optional joining from step vii) of the process according to the invention.

[0166] In all examples, both polymer film A1) 110 and polymer film A2) 120 were translucent because TiO2 was used as a filler material. Therefore, the watermark 140 was only visible in transmitted light, as shown in Figure 3a and 3bfor security document A) 100 shown from example 3. In reflected light, as in Figure 3 As shown, the security document A) 100 appeared in all examples as a homogeneous foil without a recognizable watermark 140. Figure 3a is intended to illustrate the lighting conditions in transmitted light conditions, i.e., the conditions when the light from a light source is captured through the safety document A) 100. Figure 3b The watermark 140 is shown frontally in full transmitted light. Examples 2 and 4 also showed the same results as those from Figure 3, 3a and 3b , which is why they are not shown separately here. The light transmission of the TiO2-filled security document A) in areas without a watermark was 45% for a thickness of 15 µm, 26.5% for a thickness of 30 µm, 13.6% for a thickness of 95 µm, and 10.6% for a thickness of 120 µm.

[0167] Figure 4Figure 3 shows a safety document according to the invention (A) from Example 3 in a microtome section taken at 500x magnification using a KEYENCE VHX 600 light microscope. The transition from polymer layer A1) 110 to polymer layer A2) 120 is indicated by a horizontal line 105, and the transition between polymer layer A2) 120 and polymer layer A3) 130 is indicated by a horizontal line 107. The thickness of polymer layer A1) 110 varies between 30 and 34 µm, the thickness of polymer layer A2) 120 varies between 36 and 41 µm, and the thickness of polymer layer A3) 130 varies between 30 and 35 µm. The security feature A4) 140 in the form of the watermark 140 is clearly visible in the middle polymer layer A2) 120 in the areas that point towards the polymer layer A1) 110, since the security document A) was laser-etched through the polymer layer A1) and not through the polymer layer A3) 130.It is clearly evident that the polymer layer A1) showed no visible changes from the laser beam at any point. The safety document A) according to Example 3 exhibited a tear strength according to DIN 53363:2003-10 of 282 N / mm², a light transmission of 11%, a stress at 10% elongation according to ISO 527-3-2019-02 of 30 MPa, and a surface energy according to DIN ISO 8296:2008 of 38 mN / m².

Claims

1. A security document A) with a first outer surface AS1) and a second outer surface AS2) opposite the first outer surface AS1), comprising at least: (A1) a first polymer film A1), (A2) a second polymer film A2), (A3) optionally at least one further transparent or translucent polymer film A3), (A4) a security feature A4), (A5) optional particles, wherein at least one of the polymer films selected from the group consisting of the first polymer film A1), the second polymer film A2), optionally the at least one further polymer film A3), or a combination of at least two thereof, contains or consists of a thermoplastic elastomer TPE and forms at least one of the outer surfaces AS1) or AS2), wherein at least one of the polymer films A1) or A2) is translucent at least in the area where the security feature A4) is located, and the other polymer film A1) or A2) is transparent or translucent.characterized by the fact that the security feature A4) is an engraving, in particular a laser engraving, in the second polymer film A2) which is designed in such a way that it has the function of a watermark.

2. The security document A) according to claim 1, wherein the polymer film A2) contains a laser marking additive, preferably in an amount of ≥ 0.1 wt.% to ≤ 4.5 wt.%, based on the total mass of the polymer film A2).

3. The safety document A) according to one of the preceding claims, wherein the TPE of the first polymer film A1) and / or the second polymer film A2) is a thermoplastic polyurethane and preferably has a hardness in the range of 45 Shore D to 95 Shore D.

4. The safety document A) according to one of the preceding claims, wherein the TPE is selected from the group consisting of a thermoplastic polyamide elastomer, a thermoplastic olefin-based elastomer, preferably PP / EPDM, a thermoplastic styrene block copolymer, such as SBS, SEBS, SEPS, SEEPS and MBS, a thermoplastic polyurethane TPU, a copolyester elastomer, a polyether block amide, a copolyester, a polycarbonate, a polyethylene terephthalate PET, a polyethylene terephthalate glycol PETG or a mixture of at least two thereof.

5. The security document A) according to one of the preceding claims, wherein the outer surfaces AS1) and AS2) of the security document A) are a polymer film A1), A2) or A3) which includes or consists of a TPU.

6. The security document A) according to one of the preceding claims, wherein at least all polymer films A1), A2) and optionally A3) consist exclusively of polymers, in particular thermoplastic polyurethanes, preferably the entire security document A) consists of polymers, in particular thermoplastic polyurethanes, excluding the optional particles A5).

7. The security document A) according to one of the preceding claims, wherein the security document A) comprises at least one further polymer film A3), wherein the at least one further polymer film A3) contains the TPE in an amount in the range of 50 to 100 wt.%, preferably 60 to 90 wt.%, particularly preferably 70 to 80 wt.%, based on the total weight of the respective polymer film A3).

8. The safety document A) according to one of the preceding claims, wherein at least one of the polymer films selected from the group consisting of the first polymer film A1), the second polymer film A2) or both polymer films A1) and A2) contains the TPE in an amount in the range of 50 to 100 wt.%, preferably 60 to 90 wt.%, particularly preferably 70 to 80 wt.%, based on the total weight of the respective polymer film A1) or A2).

9. The safety document A) according to one of the preceding claims, wherein at least one of the polymer films selected from the group consisting of the first polymer film A1), the second polymer film A2) or both comprise a polymer selected from the group consisting of a thermoplastic polyurethane TPU, a copolyester or a mixture of at least two thereof or mixtures of TPU and further TPEs in an amount in the range of 50 to 100 wt.%, preferably 60 to 90 wt.%, particularly preferably 70 to 80 wt.%, based on the total weight of the respective polymer film A1) or A2).

10. The security document A) according to one of the preceding claims, wherein the security document A) comprises a further security feature A6), selected from the group consisting of a hologram, a print, a security thread, a fluorescent fiber, particles, a dye, a security pigment, carbon black, metallic or non-metallic micro- or nanoparticles, magnetic particles, an embossing or a combination of at least two thereof.

11. The security document A) according to one of the preceding claims, wherein the security document A) has at least one of the following properties: a. a tear strength in the range of 50 N / mm² to 400 N / mm² determined according to DIN 53363:2003-10; b. a tensile strength in the range of 20 MPa to 200 MPa determined according to ISO 527-3:1995; c. a light transmission in the range of 0% to 85%, determined according to ISO 13468-2:2019; d. a security pigment content in the range of 0.1 to 10 wt.%, based on the total weight of the security document A); e. a crease recovery angle in the range of 120° to 170°, more preferably 130° to 160°, particularly preferably 140° to 150° according to DIN 53 890 / 91; f. a Vicat softening temperature of 60°C to 105°C, particularly preferably of 65°C to 85°C according to DIN EN ISO 306:2023-03; g.a nominal elongation at break in a range of at least 60%, preferably from 60 to 800%, measured according to DIN EN ISO 527-1:2012.

12. A method for producing a security document A) with a first outer surface AS1) and a second outer surface AS2) opposite the first outer surface AS1), comprising the steps i) providing a first transparent or translucent polymer A1'); ii) providing a second translucent or transparent polymer A2') containing at least laser marking additive; iii) optionally providing a further translucent or transparent polymer A3'); iv) melting the polymers from step i), ii) and optionally iii);v) Either combining the polymer melts from step iv) to form a first polymer film A1) from the first polymer A1'), a second polymer film A2) from the second polymer A2') and optionally a further polymer film (A3) from the first polymer A1') or from the further polymer A3') as a coextrudate, or forming a laminate from separate polymer films A1), A2), and optionally A3), formed from the melts in step iv); vi) introducing a security feature A4) in the form of a watermark by means of laser engraving into the second polymer film A2) while retaining the security document A); vii) Optionally joining, preferably by ultrasonic welding, vibration welding, or laser welding, a polymer layer A7) to one of the outer layers AS1) or AS2) over an area of ​​at least 1 mm; 2, wherein the outer surfaces AS1) and AS2) are formed by one of the polymer films A1), A2) or A3), each containing or consisting of a TPE and at least one of the polymer films A1), A2) and / or A3) is translucent.

13. The method according to claim 12, wherein the polymer film A2) contains a laser marking additive in an amount of ≥ 0.1 wt.% to ≤ 4.5 wt.%, based on the total mass of the polymer film A2).

14. The method according to one of claims 12 or 13, wherein at least one of the polymers is selected from the group consisting of polymer A1'), polymer A2'), optionally polymer A3'), a polymer selected from the group consisting of a thermoplastic polyamide elastomer, a thermoplastic olefin-based elastomer, preferably PP / EPDM, a thermoplastic styrene block copolymer, a thermoplastic polyurethane TPU, a copolyester elastomer, a polyether block amide, a copolyester, a polycarbonate, a polyethylene terephthalate PET, a polyethylene terephthalate glycol PETG or a mixture of at least two thereof, preferably TPU.

15. Use of the security document A) according to any one of claims 1 to 12 or produced according to a method according to any one of claims 13 to 14 in or as a banknote, birth certificate, postage stamp, tax stamp, visa pages of a passport, hinge for the data page of a passport or as a carrier layer of an electromagnetic shield in the passport.

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