DE102010051023A1 - Multilayered substrate useful for producing security document, preferably banknote, comprises substrate core with two superimposed plastic layers, and barrier layer, which is arranged on both major surfaces of the substrate core - Google Patents

Abstract

Multilayered substrate comprises a substrate core (2) with at least two superimposed plastic layers, where a barrier layer (8) preventing permeation of organic compounds, is respectively arranged on both major surfaces of the substrate core. Independent claims are also included for: (1) a security document (1), preferably a banknote comprising the substrate; and (2) producing the multilayered substrate, comprising arranging each barrier layer on the two main surfaces of the substrate core with at least two superposed plastic layers.

Description

The invention relates to a multilayer substrate for the production of value documents, in particular banknotes, comprising a substrate core with at least two plastic layers arranged one above the other. The invention further relates to a method for producing the multilayer substrate and to a value document comprising such a substrate.

It is known that suitable substrates are needed for the production of value documents. For the purposes of the present invention, "value documents" are understood to mean, for example, banknotes, shares, bonds, certificates, vouchers, checks, lottery tickets, high-quality admission tickets, passports, identity cards, credit cards and other flat valuables. Such valuables can also be packaging for possibly high-quality products. The term "value document" in the context of the present invention also includes precursors of said value documents, which, for example, are not yet fit for circulation.

To produce such value documents, in particular banknotes, a paper-based substrate is often used. Paper substrates are made of fibrous material, preferably cotton fibers. In the context of the present invention, "paper" means any type of paper or papery material. In addition to paper from z. As cotton is understood in the context of the present application by "paper" and a substrate containing fibers of a polymer material. Paper that contains 100% plastic fibers is z. B. paper with the trade name "Tyvek".

In the quest for security papers with tear resistance and higher resistance to pollution was in the WO 98/15418 proposed to make a banknote completely from a plastic substrate. More recently, multilayer plastic film substrates have been developed for making value documents consisting of two or three hot laminated LLDPE / BOPP / LLDPE films (LLDPE = linear low density polyethylene, BOPP = biaxially oriented polypropylene). A layer structure consisting of two such hot-laminated films therefore has the layer sequence LLDPE / BOPP / LLDPE / LLDPE / BOPP / LLDPE. In order to combine the advantages of paper substrates with those of film substrates, multi-layer substrates, so-called hybrid substrates, have been proposed in the prior art. The WO 2004/028825 z. B. describes a layer structure in which a paper layer on both sides with foil, preferably over the entire surface, is covered.

Multilayer substrates comprising a substrate core having at least two superimposed plastic layers may be retardered by means of suitable organic compounds, such as organic solvents (eg, gasoline, petroleum ether, or toluene), plasticizers (eg, phthalates), retarders (For example, propylene glycol), esters, ethers, ketones, aldehydes, formamides, imides, sulfoxides (eg DMSO), optionally at elevated temperature, are split into two equivalent or approximately equivalent substrate halves. In the case of the above-mentioned polymer banknote with the layer sequence LLDPE / BOPP / LLDPE / LLDPE / BOPP / LLDPE, the thermal lamination between the two central, adjacent LLDPE layers is the weak point for such a counterfeit attack. In a PET / BOPP / PET substrate, consisting of two PET layers with a central layer of biaxially oriented polypropylene (BOPP), wherein between the central BOPP layer and the two outer PET layers in each case a laminating adhesive layer is arranged forms the Lamination the weak spot for a counterfeit attack. The two substrate halves, consisting of front and back, differ in extreme cases only by the imprint and the security features on the respective side. Therefore, it would be possible to combine an original page with a spoofed page and to bring the value document thus obtained into circulation.

The invention is therefore based on the object to provide an improved compared to the prior art merhrlagiges substrate.

This object is achieved by the multilayer substrate for the production of value documents and the value document according to the independent claims. The dependent claims relate to preferred embodiments and further developments of the invention.

A first aspect of the invention relates to a multilayer substrate for the production of documents of value, in particular banknotes, comprising a substrate core having at least two superimposed plastic layers, wherein on both main surfaces of the substrate core in each case a permeation of organic compounds such. As organic solvents, preventing barrier layer is arranged.

• (1) einer mittels Zersetzung von siliziumorganischen Verbindungen im Plasma erhältlichen SiO_x-Schicht;
• (2) einer Lackschicht, umfassend ein Polyepoxid als Lackbindemittel und plastifizierende Polyurethane;
• (3) einer Lackschicht, umfassend Harnstoff- oder Melamin-Formaldehyd-Harze als Bindemittel, ggf. in Kombination mit einer durch Sulfonierung erhältlichen Oberflächenmodifizierung;
• (4) einer Schicht, die durch Elektronenstrahlvernetzung, ggf. unter Zusatz von Vernetzungshilfen, wie Allylmethacrylat, Diallylphthalat, Triallylcyanurat, Triallylisocyanurat, Trimethylolpropantrimethacrylat, Triallylphosphat, oder durch UV-Strahlenvernetzung erhältliches vernetztes Polyolefin oder vernetztes Polyamid aufweist;
• (5) einer Schicht, die aus einer Zusammensetzung mit den folgenden Bestandteilen (a), (b) und (c) erhältlich ist:
• (a) einem epoxidhaltigen oder halogen- und epoxidhaltigen Metalloxidsol;
• (b) einem fluor- oder sulfohaltigen Maleinsäurehalbester- oder Maleinsäure halbamid-Mischpolymerisat der allgemeinen Strukturformel (1): -CH(COOH)-CH(COXY)-M- (1) worin M = Vinylmonomer; X = Sauerstoff oder Stickstoff; Y = -(CH₂)_n-SO₃H, -(CH₂)_n-F, oder -(CF₂)_n-H; und n = 2 bis 12 bedeuten;
• (c) einem Katalysator auf der Basis eines oder mehrerer tertiärer Amine.

The barrier layer is preferably selected from:

• (1) an SiO _x layer obtainable in plasma by decomposition of organosilicon compounds;
• (2) a paint layer comprising a polyepoxide as a paint binder and plasticizing polyurethanes;
• (3) a lacquer layer comprising urea or melamine-formaldehyde resins as a binder, optionally in combination with a surface modification obtainable by sulfonation;
• (4) a layer comprising crosslinked polyolefin or crosslinked polyamide obtainable by electron beam crosslinking, optionally with the addition of crosslinking aids, such as allyl methacrylate, diallyl phthalate, triallyl cyanurate, triallyl isocyanurate, trimethylolpropane trimethacrylate, triallyl phosphate, or by UV radiation crosslinking;
• (5) a layer obtainable from a composition comprising the following components (a), (b) and (c):
• (a) an epoxide-containing or halogen- and epoxide-containing metal oxide sol;
• (b) a fluoro- or sulfo-containing maleic acid half-ester or maleic acid half-amide copolymer of the general structural formula (1): -CH (COOH) -CH (COXY) -M- (1) wherein M = vinyl monomer; X = oxygen or nitrogen; Y = - (CH ₂ ) _n -SO ₃ H, - (CH ₂ ) _n -F, or - (CF ₂ ) _n -H; and n = 2 to 12;
• (c) a catalyst based on one or more tertiary amines.

The substrate core, which has at least two plastic layers arranged one above the other, may preferably have been exposed to treatment by means of electron beam crosslinking. Here, chemical bonds are formed within the individual plastic layers and at the interface between two different plastic layers (which are joined together, for example by hot lamination or via a laminating adhesive layer), which leads to increased resistance to splitting of the multilayer substrate. The electron beam crosslinking can be done either before the application of the barrier layers on the substrate core, or after the application of the barrier layers on the substrate core.

The at least two plastic layers of the substrate core arranged one above the other can preferably each comprise a polyolefin which, independently of one another, is e.g. B. from the group polyethylene, low density polyethylene (LDPE), linear low density polyethylene (LLDPE), medium density polyethylene (MDPE), high density polyethylene (HDPE) and biaxially oriented polypropylene (BOPP) is selected.

In particular, the substrate core three superimposed plastic layers, for. B. two PET layers with an interposed embedded layer of biaxially oriented polypropylene (BOPP), or two superimposed plastic layers, for. B. PET layers, with an interposed embedded paper layer.

It is further preferred that the substrate core of the multilayer substrate has been exposed to electron beam crosslinking, in particular a treatment with β-radiation (electron radiation) and a radiation dose of 1 kGy to 200 kGy, preferably of 1.5 kGy to 160 kGy and more preferably of 1 , 5 kGy to 80 kGy, the radiation source being in particular a Rhodotron plant.

A second aspect of the invention relates to a value document, in particular a banknote, which has a substrate according to the first aspect of the invention.

A third aspect of the invention relates to a method for producing the multilayer substrate according to the first aspect of the invention, comprising the step of arranging each one of the permeation of organic compounds, such. As organic solvents, preventing barrier layer on the two main surfaces of a substrate core with at least two superimposed plastic layers. In a preferred embodiment, the substrate core is treated before or after the step of arranging the barrier layers by electron beam crosslinking.

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

The multilayer substrate according to the invention for the production of value documents, in particular banknotes, comprises a substrate core having at least two superimposed plastic layers, wherein on both main surfaces of the substrate core each one permeation of organic compounds such. As organic solvents, preventing barrier layer is arranged. It has been found that the migration or permeation of organic compounds into the substrate or between the individual substrate layers and thus the cleavage of the multilayer substrate can be made considerably more difficult by means of a barrier layer.

Barrier layers, the permeation of organic compounds such. For example, organic solvents, which can be prevented in the multilayer substrate and used for the multilayer substrate according to the invention, are known in the art. As a barrier layer is z. Example, a obtainable by decomposition of organosilicon compounds in the plasma SiO _x layer (see Vak. Prax. 1991, 3, page 27 ). Furthermore, the barrier layer can be formed by a lacquer layer which comprises a polyepoxide as lacquer binder and plasticizing polyurethanes (see US Pat DE 3 447 022 A1 ). Alternatively, the lacquer layer may comprise urea or melamine-formaldehyde resins as a binder, optionally in combination with a surface modification obtainable by sulfonation (see GB 2 069 870 A ).

The barrier layer used is preferably a layer which has crosslinked polyolefin or crosslinked polyamide obtainable by electron beam crosslinking, if appropriate with the addition of crosslinking aids, such as allyl methacrylate, diallyl phthalate, triallyl cyanurate, triallyl isocyanurate, trimethylolpropane trimethacrylate, triallyl phosphate, or by UV radiation crosslinking. The electron beam crosslinking of polymers is known in the art (see, for example, the brochure "Drying of Coatings by Electron Beams" of "ELECTRON CROSSLINKING AB", SE-30244 Halmstad, June 2006 ).

The crosslinked by electron beams or by UV rays polyolefin may, for. From the group consisting of polyethylene, low density polyethylene (LDPE), linear low density polyethylene (LLDPE), medium density polyethylene (MDPE) and high density polyethylene (HDPE). To adjust the material properties, it is possible to provide a mixture of different crosslinked polyolefins for the barrier layer, in particular to provide a mixture containing low density polyethylene (LDPE). In addition to the blends of various crosslinked polyolefins described above, it is further preferred that the barrier layer contain copolymers prepared from monomers selected from the group of mono-olefins, especially ethylene, propylene, but-1-ene, isobutylene , Hex-1-ene, methylpent-1-ene, hept-1-ene, oct-1-ene and the higher homologues, vinylcyclohexane, the di-olefins, in particular polyisoprene, polybutadiene, the cyclic olefins, in particular cyclopentene, cyclohexene and the higher homologues, the cyclic di-olefins such as vinylcyclohexene, or the bicyclic compounds such as norbornene. In particular, it is preferred that the barrier layer comprises copolymers obtainable from monomers of ethylene and monomers selected from the group of mono-olefins, di-olefins, cyclic olefins, cyclic di-olefins, the bicyclic compounds, or from the group vinyl acetate , Alkyl (meth) acrylates, acrylic acid, acrylic acid derivatives.

To modify the material properties of the security substrate, the at least one layer may also contain additives, in particular polymeric additives such as polypropylene (PP), polycarbonate (PC), polymethyl methacrylate (PMMA), ethylene-vinyl acetate (EVA), ethylene-acrylic acid copolymers, or ionomers Additives, such as ethylene-acrylic acid ionomers. By suitable choice of these additives and their proportions in the at least one layer, properties such as strength, color, etc. of the substrate can be easily adjusted.

The crosslinked by electron beams or by UV rays polyamide or copolyamide may, for. Example, be prepared from monomers selected from the group of diamines, dicarboxylic acids, aminocarboxylic acids, lactams, such as polyamide 4, polyamide 6, polyamide 11, polyamide 12, polyamide 4/6, nylon 6/6, nylon 6/9, polyamide 6/10, polyamide 6/12, polyamide 12/12, or selected from the group consisting of hexamethylenediamine, isophthalic acid and terephthalic acid. In the context of the present application, the term "crosslinked polyamides" also encompasses the term "crosslinked copolyamides" as a subgroup of crosslinked polyamides.

• (a) einem epoxidhaltigen oder halogen- und epoxidhaltigen Metalloxidsol;
• (b) einem fluor- oder sulfohaltigen Maleinsäurehalbester- oder Maleinsäurehalbamid-Mischpolymerisat der allgemeinen Strukturformel (1): -CH(COOH)-CH(COXY)-M- (1) worin M = Vinylmonomer; X = Sauerstoff oder Stickstoff; Y = -(CH₂)_n-SO₃H, -(CH₂)_n-F, oder -(CF₂)_n-H; und n = 2 bis 12 bedeuten;
• (c) einem Katalysator auf der Basis eines oder mehrerer tertiärer Amine. Die Beschichtung kann z. B. drucktechnisch auf den Substratkern aufgebracht werden.

In particular, it is preferred as a barrier layer from the EP 0 921 169 A known layer consisting of a composition comprising the following components (a), (b) and (c) z. B. is available by drying:

• (a) an epoxide-containing or halogen- and epoxide-containing metal oxide sol;
• (b) a fluorochemically or sulpho-containing maleic acid half-ester or maleic acid hemamide copolymer of the general structural formula (1): -CH (COOH) -CH (COXY) -M- (1) wherein M = vinyl monomer; X = oxygen or nitrogen; Y = - (CH ₂ ) _n -SO ₃ H, - (CH ₂ ) _n -F, or - (CF ₂ ) _n -H; and n = 2 to 12;
• (c) a catalyst based on one or more tertiary amines. The coating may, for. B. be applied by printing on the substrate core.

The barrier layer may preferably have a thickness of 1 micron to 20 microns.

The barrier layer can be present over the entire surface, so that the entire substrate core is covered by the barrier layer. Alternatively, the barrier layer may be partially applied to the substrate core, for. B. targeted to make a forgery attack visible.

The barrier layer can be arranged directly on the substrate core. In this case, the barrier layer is preferably with a Provided ink receiving layer on which the security printing is done. After printing on the substrate, a protective lacquer can optionally be applied to the printed substrate.

Alternatively, the barrier layer is not disposed directly on the substrate core. In this case, the substrate core z. B. provided with a paint receiving layer on which the security printing. The barrier layer is applied above the security pressure and can optionally be covered by a protective varnish.

As an additional or independent measure to avoid splitting the at least two superimposed plastic layers comprising multilayer substrate in the course of a counterfeiting attack with organic compounds such. As organic solvents, adjacent plastic layers in the substrate core can be connected to each other by means of electron beam crosslinking. The electron beam crosslinking can be done either before the application of the barrier layers on the substrate core, or after the application of the barrier layers on the substrate core. In the case of a substrate core with plastic layers stacked on top of one another by thermal lamination (which are each formed from LLDPE, for example), the electron beam crosslinking is suitably carried out in such a way that the parameters acceleration voltage [kV], electron current [mA] and substrate transport speed are finely adjusted [m / min], in particular in the thermolaminated surface area, a post-crosslinking takes place. The thermolaminated region, which forms the weak point in the case of a counterfeit attack, can be enhanced in this way against splitting. In the case of a substrate core with plastic layers (eg a PET film and a BOPP film) stacked on top of one another using a laminating adhesive layer, the electron beam crosslinking is suitably carried out in such a way that the parameters acceleration voltage [kV], electron current [mA] can be finely adjusted. and substrate transport speed [m / min], in particular in the region of the laminating adhesive layer, a post-crosslinking takes place. The lamination, which forms the weak point in the case of a counterfeit attack, can be reinforced in this way against splitting. In electron beam crosslinking, it is advantageous to use β radiation, that is to say high-energy electron radiation. The radiation dose of the β radiation used is preferably 1 kGy to 200 kGy, more preferably 1.5 kGy to 160 kGy and particularly preferably 1.5 kGy to 80 kGy. The electron radiation can be provided by means of a Rhodotron system as a radiation source. A rhodotron system is an electron accelerator for generating high-energy electron radiation (β-radiation). Such a device has the advantage that broad substrate webs can be crosslinked by exposure to β-radiation.

Further exemplary embodiments and advantages of the invention are explained below by way of example with reference to the accompanying figures. The examples represent preferred embodiments which in no way limit the invention. The figures shown are schematic representations that do not reflect the real proportions but serve to improve the clarity of the various embodiments.

In detail, the figures show:

1 a sectional view of an embodiment of the inventive value document;

2 to 6 : Sectional views of further embodiments for the value document according to the invention.

This in 1 represented value document 1 , z. B. a banknote, comprises a substrate core 2 consisting of two polymer films bonded by means of hot lamination 3 and 4 is formed. Each of the films 3 and 4 is a coextruded laminate consisting of an LLDPE layer 5 , a BOPP layer 6 and an LLDPE layer 7 , Process for producing the substrate core 2 are known in the art (see for example: EL Prime, DH Solomon, Angew. Chemistry, 2010, 122, 2-13 ). Hot lamination between the two adjacent LLDPE layers 5 represents the vulnerability for a scission attack by means of organic compounds, such. As gasoline, petroleum ether or toluene, above and below the substrate core 2 there is one barrier layer each 8th , As a barrier layer 8th can z. B. from the EP 0 921 169 A known layer can be used by means of conventional printing processes, such as gravure, flexographic or screen printing, on the substrate core 2 is applied. The barrier layer 8th is additionally provided with an optional ink accepting layer 9 provided to the adhesion of the printed layer applied to the multilayer substrate 10 to improve. Above the print layer 10 Optionally, a protective coating 11 be upset. The print layer 10 has security features produced by printing technology and may additionally include additional security features, such as a foil element or the like.

In the 1 shown barrier layer 8th is completely on the substrate core 2 applied. In this way, the permeation of organic compounds, such as gasoline, petroleum ether or toluene, into the substrate core is prevented. Alternatively, the barrier layer 8th but also part of the area present z. B. to make targeted a counterfeiting attack with organic compounds. The ink acceptance layer 9 may be equally present over the whole area or part of the area. A merely partial application of the ink receiving layer 9 can z. B. are used for the production of a transparent see-through window.

In the in 1 shown value document 1 is the barrier layer 8th directly on the substrate core 2 arranged. Alternatively, the barrier layer 8th but also indirectly on the substrate core 2 be arranged as in the 2 shown value document 12 is shown.

In the in 2 shown value document 12 is the substrate core 2 with the in 1 shown substrate core 2 identical. Above and below the substrate core 2 there is a paint acceptance layer 9 that with a print layer 10 is provided. The barrier layer 8th is above the print layer 10 Applied and optional with a protective coating 11 be provided.

This in 3 shown value document 13 includes a substrate core 2 with three plastic layers, namely a central BOPP film 14 , which at their two main surfaces by means of Kaschierkleberschichten (not shown), each with a PET film 16 connected is. Above the PET film 16 are located, similar to the one in 1 shown value document 1 , a barrier layer 8th , an optional ink receiving layer 9 , a security print 10 and an optional protective coating 11 in this order. The two laminating adhesive layers (not shown) between the central BOPP film 14 and the two PET films 16 each provide the vulnerability for a cleavage attack by means of organic compounds such. As gasoline, petroleum ether or toluene, is.

In the in 4 shown value document 17 includes the substrate core 2 two BOPP films 19 by means of a central laminating adhesive layer 18 laminated together. Above the BOPP film 19 are similar to those in the 1 and 3 shown value documents 1 respectively. 13 , a barrier layer 8th , an optional ink receiving layer 9 , a security print 10 and an optional protective coating 11 in this order. The laminating adhesive layer 18 between the BOPP slides 19 represents the vulnerability for a scission attack by means of organic compounds, such. As gasoline, petroleum ether or toluene, is.

This in 5 shown value document 20 includes a substrate core 2 with three plastic layers, namely a central BOPP film 14 , on their two main surfaces on Kaschierschichten 15 each with a PET film 16 connected is. The layer structure above and below the substrate core 2 is similar to the one in 2 shown value document 12 , Above the PET film 16 There is an optional ink accepting layer 9 , a print layer 10 , a barrier layer 8th and an optional protective coating 11 in this order.

In the in 2 to 5 shown value documents corresponds to the nature of the respective contained barrier layer that of 1 shown value document 1 , in which as a barrier layer from the EP 0 921 169 A known; applied by printing technology layer is used. Alternatively, as a barrier layer but also a obtainable by decomposition of organosilicon compounds in the plasma SiO _x layer or a lacquer layer comprising a polyepoxide lacquer binder and plasticizing polyurethanes, or a lacquer layer comprising urea or melamine-formaldehyde resins as a binder, if necessary in combination with a surface modification obtainable by sulfonation, or a layer comprising crosslinked polyolefin or crosslinked polyamide obtainable by electron beam crosslinking, optionally by using crosslinking aids, or by ultraviolet ray crosslinking. For example, this includes in 6 shown value document 21 two foils bonded by means of hot lamination 3 and 4 , Each of the slides 3 and 4 is a coextruded film consisting of an LLDPE layer 5 , a BOPP layer 6 and a layer 22 made of electron-crosslinked polyolefin or crosslinked polyamide. The layer 22 serves as a barrier layer 8th , The substrate core 2 is therefore through the LLDPE layers 5 and the BOPP layers 6 educated. Hot lamination between the two adjacent LLDPE layers 5 represents the vulnerability for a scission attack by means of organic compounds, such. As gasoline, petroleum ether or toluene, above the barrier layer 22 There is an optional ink accepting layer 9 , a print layer 10 and an optional protective coating 11 ,

In the in 3 and 5 shown value documents 13 respectively. 20 may instead of the central BOPP film 14 a paper layer can be used. Multilayer substrates, so-called hybrid substrates, with a paper layer covered on both sides with film are e.g. B. from the WO 2004/028825 known.

As an additional measure to avoid the splitting of the multilayer substrate comprising several plastic layers into the in 1 to 6 shown value documents in the course of a counterfeiting attack with organic compounds such. As gasoline, petroleum ether or toluene, the substrate core 2 be treated by electron beam crosslinking. In the case of a substrate core 2 with plastic layers stacked on top of one another by thermal lamination (see, for example, those in US Pat 1 . 2 and 6 shown value documents 1 . 12 respectively. 21 ), the electron beam crosslinking is carried out so that a post-crosslinking takes place especially in the thermolaminated area. The thermolaminated area, which in the case of Counterfeiting attack forms the vulnerability can be strengthened in this way against splitting. In the case of a substrate core 2 with plastic layers arranged on top of each other by means of a laminating adhesive layer (see, for example, those in US Pat 3 . 4 and 5 shown value documents 13 . 17 respectively. 20 ), the electron beam crosslinking is carried out in a suitable manner so that, in particular in the region of the laminating adhesive layer, postcrosslinking takes place. The lamination, which forms the weak point in the case of a counterfeit attack, can be reinforced in this way against splitting.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• WO 98/15418 [0004]
• WO 2004/028825 [0004, 0041]
• DE 3447022 A1 [0018]
• GB 2069870 A [0018]
• EP 0921169 A [0023, 0033, 0040]

Cited non-patent literature

• Vak. Prax. 1991, 3, page 27 [0018]
• "Drying of coatings by means of electron beams" of the company "ELECTRON CROSSLINKING AB", SE-30244 Halmstad, June 2006 [0019]
• EL Prime, DH Solomon, Angew. Chemistry, 2010, 122, 2-13 [0033]

Claims (13)

Multi-layered substrate for the production of value documents, in particular banknotes, comprising a substrate core with at least two superimposed plastic layers, wherein on both main surfaces of the substrate core in each case a permeation of organic compounds preventing barrier layer is arranged. The substrate of claim 1, wherein the barrier layer is selected from: (1) an SiO _x layer obtainable in the plasma by decomposition of organosilicon compounds; (2) a paint layer comprising a polyepoxide as a paint binder and plasticizing polyurethanes; (3) a lacquer layer comprising urea or melamine-formaldehyde resins as a binder, optionally in combination with a surface modification obtainable by sulfonation; (4) a layer comprising crosslinked polyolefin or crosslinked polyamide obtainable by electron beam crosslinking, optionally with the addition of crosslinking aids, such as allyl methacrylate, diallyl phthalate, triallyl cyanurate, triallyl isocyanurate, trimethylolpropane trimethacrylate, triallyl phosphate, or by UV radiation crosslinking; (5) a layer obtainable from a composition comprising the following components (a), (b) and (c): (a) an epoxy-containing or halogen and epoxide-containing metal oxide sol; (b) a fluorochemically or sulpho-containing maleic acid half-ester or maleic acid halamidamide copolymer of the general structural formula: -CH (COOH) -CH (COXY) -M-, wherein M = vinyl monomer, X = oxygen or nitrogen, Y = - (CH ₂ ) _n -SO ₃ H, - (CH ₂ ) _n -F or - (CF ₂ ) _n -H, and n = 2 to 12; (c) a catalyst based on one or more tertiary amines. The substrate of claim 1 or 2, wherein the substrate core is treated by electron beam crosslinking. Substrate according to one of claims 1 to 3, wherein the at least two superimposed plastic layers of the substrate core each polyolefin, which independently z. B. from the group consisting of polyethylene, low density polyethylene (LDPE), linear low density polyethylene (LLDPE), medium density polyethylene (MDPE), high density polyethylene (HDPE) and biaxially oriented polypropylene (BOPP) is selected. Substrate according to one of claims 1 to 3, wherein the substrate core has three superimposed plastic layers, for. B. two PET layers with an interposed embedded layer of biaxially oriented polypropylene (BOPP), or two superimposed plastic layers, for. B. PET layers, with an interposed embedded paper layer having. A security substrate according to claim 3 or claim 3, wherein the substrate core is treated by electron beam crosslinking, namely by means of β-radiation and a radiation dose of 1 kGy to 200 kGy, preferably of 1.5 kGy to 160 kGy and more preferably of 1, 5 kGy to 80 kGy, wherein the radiation source is preferably a Rhodotron plant. Security document, in particular banknote, with a substrate according to at least one of claims 1 to 6. A method for producing a multilayer substrate for the production of value documents, in particular banknotes, comprising the step of arranging in each case one of the permeation of organic compounds preventing barrier layer on the two main surfaces of a substrate core having at least two superimposed plastic layers. The method of claim 8, wherein the barrier layer is selected from: (1) an SiO _x layer obtainable in the plasma by decomposition of organosilicon compounds; (2) a paint layer comprising a polyepoxide as a paint binder and plasticizing polyurethanes; (3) a lacquer layer comprising urea or melamine-formaldehyde resins as a binder, optionally in combination with a surface modification obtainable by sulfonation; (4) a layer comprising crosslinked polyolefin or crosslinked polyamide obtainable by electron beam crosslinking, optionally with the addition of crosslinking aids, such as allyl methacrylate, diallyl phthalate, triallyl cyanurate, triallyl isocyanurate, trimethylolpropane trimethacrylate, triallyl phosphate, or by UV radiation crosslinking; (5) a layer obtainable from a composition comprising the following components (a), (b) and (c): (a) an epoxy-containing or halogen and epoxide-containing metal oxide sol; (b) a fluorochemically or sulpho-containing maleic acid half-ester or maleic acid halamidamide copolymer of the general structural formula: CH (COOH) -CH (COXY) -M-, wherein M = vinyl monomer, X = oxygen or nitrogen, Y = - (CH ₂ ) _n -SO ₃ H, - (CH ₂ ) _n -F or - (CF ₂ ) _n -H, and n = 2 to 12; (c) a catalyst based on one or more tertiary amines. The method of claim 8 or 9, wherein the substrate core is treated before or after the step of arranging the barrier layers by electron beam crosslinking. Method according to one of claims 8 to 10, wherein the at least two superimposed plastic layers of the substrate core each polyolefin, which are independent of each other z. B. from the group consisting of polyethylene, low density polyethylene (LDPE), linear low density polyethylene (LLDPE), medium density polyethylene (MDPE), high density polyethylene (HDPE) and biaxially oriented polypropylene (BOPP) is selected. Method according to one of claims 8 to 10, wherein the substrate core has three superimposed plastic layers, for. B. two PET layers with an interposed embedded layer of biaxially oriented polypropylene (BOPP), or two superimposed plastic layers, for. B. PET layers, with an interposed embedded paper layer having. A method according to claim 10 or claim 1, wherein the substrate core is treated by electron beam crosslinking, namely by means of β-radiation and a radiation dose of 1 kGy to 200 kGy, preferably of 1.5 kGy to 160 kGy and more preferably of 1, 5 kGy to 80 kGy, and wherein the radiation source is preferably a Rhodotron plant.

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