EP0071121B1 - Forge-proof document - Google Patents

Abstract

The tamper-proof document consists of a photographic material as information carrier comprising front- and back gelatine layers, the outer of the gelatine layers of which contain particles of a homo- or copolymer of an acrylic and/or methacrylic acid ester. The information carrier is laminated on one or both sides to a transparent foil by means of a hardenable adhesive. The document is remarkably safe against falsification.

Description

The invention relates to a photographic information carrier which is laminated on one or both sides with plastic films.

Forgery-proof documents are becoming increasingly important. You will e.g. used in the form of credit cards from banks, retail stores, oil companies, airlines or credit companies to facilitate cashless payments. Such documents contain information that relates to the owner as well as the body issuing the document and that is in both interests to be protected against counterfeiting. There has been no shortage of attempts to provide information carriers of the type mentioned above in a forgery-proof manner.

For example, it is known to laminate a card printed with information between two foils. In this case, the laminating film is prepared in places so that it does not adhere to the prepared areas on the paper surface of the films. An attempt to subsequently peel off the laminating film then has the consequence that when the unprepared areas are reached, the tear breaks away from the paper surface due to the lower resistance and tears into the paper surface (DE-OS 2 511 367).

According to another proposal, a printed information carrier consisting of a paper card and a film border, a so-called “composite rivet”, is welded between two transparent films. In this way of working, the foil border provides for an edge welding that encompasses the edges of the paper card, which makes it difficult to split the welded card (DE-OS 2 756 691).

FR-A-1584105 describes a credit card consisting of a rigid plastic film, to which an adhesive layer consisting of acrylate copolymer, gelatin, plasticizer and solvent is applied, whereupon this layer structure is laminated onto a photographic layer with a support.

From GB-PS 1 518946 it is known to weld a photographic paper as an information carrier into a pair of transparent laminated foils by applying pressure and temperature. Commercial films are used for this purpose, which consist of an outer polyethylene terephthalate layer and an inner polyethylene layer.

A disadvantage of the known lamination processes is that the foils used for this purpose bond only incompletely to the surface of the information carrier during welding and thus offer only limited protection against counterfeiting. Edge welding also does not mean any significant improvement under these circumstances, as it can be easily removed and replaced again. The known lamination processes also have the disadvantage that the laminated film can be separated from the paper backing by heating or by chemical means.

The invention has for its object to provide a tamper-proof document with an information carrier in the form of a photographically and printing technology prepared photographic material in which the entire surface of the information carrier is inextricably linked with a transparent film material and the information attached to the information carrier without destroying the Information carriers are no longer accessible and are therefore reliably protected against subsequent changes.

The invention relates to a forgery-proof document consisting of an information carrier provided with information on one or both sides with at least one transparent film laminated by means of an adhesive layer and formed from a photographic material, the information carrier at least one gelatin layer carrying a photographic silver or dye image, optionally one has an outer gelatin-containing protective layer attached on the emulsion side and an outer gelatin-containing protective layer and an outer backside gelatin-containing layer and at least the outer layers of the gelatin-containing particles, the size of which is smaller than 0.1 11 m, of a homo- or copolymer of an acrylic acid or and contains methacrylic acid ester. If necessary, these homopolymers or copolymers can also contain small amounts of e.g. contain up to 10 mol% of other comonomers in polymerized form. When selecting these additional components, care must be taken to ensure that the polymer remains essentially water-insoluble.

The homo- or copolymers of acrylic acid and / or methacrylic acid esters contained in the gelatin layers of the information carrier - hereinafter referred to as polymer - are based on aliphatic C ₁ to C ₁₂ esters. The polymers are added to the casting solutions used to prepare the gelatin layers in the form of latices, which can be prepared by generally known processes with a solids content of 20 to 60% by weight and a particle size of less than 0.1 ₁₁ m. Particles with a size of 0.01 to 0.07 11 m are preferred for the present application. The corresponding methyl, ethyl and butyl esters are particularly suitable. The ethyl esters and in particular polyethyl acrylate are preferred.

To improve the printability and writability, the gelatin layers, in particular the outer layers, of the information carrier contain matting agents, for example inorganic matting agents, such as silicon dioxide, titanium dioxide, magnesium oxide, aluminum oxide, barium sulfate, calcium carbonate or glass powder; or organic matting agents such as starch, cellulose esters, for example cellulose acetate propionate, cellulose ethers, for example ethyl cellulose; or synthetic products, such as homopolymers or copolymers of, for example Vinyl acetate, vinyl carbonate, esters of acrylic acid and methacrylic acid, for example methyl methacrylate, acrylonitrile or styrene. Polyacrylonitrile is preferred. The particle sizes of the matting agents used according to the invention are 1 to 15 11 m, preferably 50% of the matting particles having a size of 4 to 7 11 m. A particularly preferred particle size is 2.5 to 3.5 ₁ 1m. Matting particles of this size guarantee excellent reproduction of identification features applied using printing technology down to the finest details (guilloche print) and the ability to label the information carrier with the usual writing materials.

The matting agents are expediently added to the casting solutions of the gelatin layers in the form of aqueous dispersions.

Matting agents are not necessary in the inner gelatin layers. However, if this is e.g. should be of importance for the production and processing of the information carrier, this should also be incorporated without impairing the quality of the finished document.

When used in outer layers, matting agents can cause layer opacity, so that an underlying developed silver image appears behind a milky veil. This can be corrected by adding small amounts of polycarbocyclic aromatic sulfonic acids or their water-soluble salts, as described in BE-PS 738 856, to the outer layer.

The gelatin layers of the information carrier contain, based on the gelatin content of the dry layers, 10 to 50% by weight of polymer (dry weight), preferably 25 to 40% by weight and up to 40% by weight, preferably 20 to 30% by weight, of matting agent .

Otherwise, the gelatin layers of the information carrier may contain the additives customary for photographic layers, such as hardening agents, e.g. Formaldehyde, mucochloric acid, triacryl formal, triazine hardener, epoxy compounds, aziridines, vinylsulfonyl compounds, carbodiimides or hardeners of the carbamoylonium and carbamoyloxypyridinium compound type, hardening accelerators, e.g. Resorcinol, polyvinyl acetams and polyvinyl acetones such as poly-N-vinyl pyrrolidone and polyvinyl-2-oxazolidone as antifoggants, antistatic agents such as polyalkylene compounds, polyoxyalkylene esters of fatty acids, e.g. Polyoxyethylene glycol (molecular weight about 300), oleic acid esters, urethanes or esters of alkoxylated hydroxyl compounds as described in DE-PS 706 563, or alkali, alkaline earth or ammonium salts of inorganic acids or of organic sulfonic and carboxylic acids. The gelatin layers can also contain the usual coating aids or wetting agents, such as saponin, dialkylsulfosuccinic acid salts, salts of alkylsulfonic acids or of alkylaryl polyether sulfonic acids, carboxy-alkylated polyethylene glycol ethers or esters or fluorine-containing organic wetting agents of known structure, in particular perfluorinated carbon or sulfonic acids or salts thereof.

The information carrier will generally consist of a photographic material which is constructed in a conventional manner, that is to say a light-sensitive silver halide emulsion layer, on a conventional layer carrier. The silver or dye information contained in this layer is produced by imagewise exposure and the usual photographic processing. Both photographic paper and films containing black-and-white or color photographic records, image and / or characters and / or other information or other identification features can be used as information carriers. The layer support of such photographic information supports can consist of the usual materials used in technical or image photography. Examples include: papers, papers provided with reflective layers, polyolefin-coated papers, the usual film supports, e.g. made of cellulose triacetate or polyester, optionally as a pigmented, opaque substrate. The photographic emulsion or auxiliary layers of such information carriers have the compositions generally used in photographic materials.

Examples of light-sensitive photographic layers with which the information carrier can be equipped are layers which are based on non-sensitized silver halide emulsions or spectrally sensitized silver halide emulsions. The known gelatin layers used for the various photographic black and white and color processes, negative, positive and diffusion transfer processes or printing processes are therefore suitable. Not only gelatin alone can be contained as a binder in the photographic gelatin layers. In addition to gelatin, you can also use chemically modified gelatins, e.g. acylated, acetylated, hydroxylated, esterified or modified by graft polymerization in a known manner gelatins, or mixtures with other hydrophilic colloids, e.g. Contain cellulose derivatives, polyvinyl alcohols, polyvinyl pyrrolidones, hydrolyzed polyvinyl acetates, alginic acid, colloidal ablumine or zein.

The plastics used for the substrate of the information carrier - e.g. the plastic with which the paper base is laminated or the plastic from which the film base is made - which also includes cellulose esters - and the plastics from which the foils used to laminate the information carrier should preferably be selected so that the softening point of the Plastic of the substrate is lower than that of the film material.

If polyolefin-coated paper is used as the layer support for the information carrier, it has proven expedient to equip the paper with a polyolefin, the Melting point is about 10-30 ° C lower than the melting point of the film of the film material carrying the adhesive layer.

Before lamination, the information carrier is provided with halftone and line recordings by imagewise exposure and photographic processing, e.g. with a passport photo and the associated printed and handwritten information.

In addition to this information, the information carrier can contain further security or identification features of the most varied of types, these being able to be generated both photographically and by labeling, printing or embossing. Of course, e.g. machine, magnetically and optically readable data can also be attached. In this respect, the information carrier according to the invention does not differ in any way from the information carriers used in known documents.

Other security features, visible or imperceptible to the eye, e.g. substances absorbing UV light can be stored in the information carrier, e.g. in the layer support, if this consists of paper, for example as a watermark, or in the outer film, e.g. be contained in the composite film. Various possibilities of equipping forgery-proof documents with such security features are e.g. described in the following publications: DE-OS 3013238, DE-OS 1 446851, DE-OS 2 908 742, US-PS 3 679 448, GB-PS 1 519 715, DE-AS 2 756 692, US-PS 2 373 540 and U.S. Patent 4,066,873.

Thermoplastics, such as e.g., are suitable as transparent film materials for the lamination of the information carrier. Polyethylene, polypropylene, cellulose esters, polyvinyl acetate, polystyrene, polyvinyl chloride, polyvinylidene chloride, polyvinyl fluoride, polytetrahalogenethylene, polycarbonate, in particular based on bisphenol A, polyester, in particular based on polyethylene and polybutylene terephthalate, polyamides, e.g. Polyamide-6 or polyamide-6,6, polyamide-12 or copolyamides.

So-called composite films made of individual films of the same and different chemical composition can of course also be used. Examples include: polyethylene / polyamides, polypropylene / polyamides or polyolefin films with other film materials such as polyesters, e.g. Polyethylene terephthalate. Suitable films and composite films are described in Ullmann's Encyclopedia or Technical Chemistry, 4th edition, volume 11, pages 673 ff.

The thickness of the films used according to the invention depends on the desired rigidity of the identification document. In general, film thicknesses between 15 and 250 microns are rich, thicknesses between 50 and 200 microns are preferred.

The surface of the film intended to take up the adhesive layer composition can be subjected to a pretreatment prior to coating to improve the bond between the film and the adhesive layer, which ensures a uniform application of the coating solution and increases its adhesive strength. Good results are obtained e.g. with a normal corona treatment.

It is of course also possible to support the adhesion of the adhesive layer applied to the carrier film by other measures, e.g. by applying a suitable substrate layer.

The usual known adhesive layers are suitable for connecting the individual foils of a composite foil as well as for connecting the foil or composite foil to the information carrier. The same adhesive layers are preferably used for both purposes.

Suitable adhesive layers contain e.g. Radically curable, ethylenically unsaturated, monomeric, oligomeric or polymeric compounds, predominantly a, β-unsaturated or vinyl group-containing compounds which contain acrylate and / or methacrylate groups. Such adhesive layers, including their use, are described in DE-OSs 2 952 322 and 3 027 759. Compounds of this type based on polyesters, α, β-unsaturated polyesters, polyethers, polyepoxides, polyurethanes, urethane-modified polyepoxides, urethane-modified polyesters and urethane-modified polyethers are particularly suitable.

Also particularly suitable are the adhesive layers described in EP-A-71 124 of the same priority and containing a poly-1,2-alkyleneimine.

The application of the adhesive layer composition to the film can be carried out using the methods customary in the paint industry, e.g. Spraying, rolling, knife coating, printing, dipping, spinning, flooding, brushing, brushing etc. take place.

The dry layer thickness of the adhesive layer depends on the desired requirements and the expected adhesive effect. In principle, dry layer thicknesses of 0.05 to 50 ₁₁ m can be used. Usable results will be achieved with 0.05 to 10 11m. Dry layer thicknesses of 0.05 to 2 μm are preferred in connection with adhesive layers which contain poly-1,2-alkyleneimine.

The EP-A-

To laminate the film provided with the adhesive layer on the surface of the information carrier, the film is heated to about 50 to 150 ° C. and pressed against the surface of the information carrier, so that a bubble-free and wrinkle-free laminate is produced. The lamination is supported by applying pressures in the range of 1 to 10 km / cm ² . When using adhesive layers made of radiation-curable material, as described, for example, in DE-OS 2 952 322, the document is generally exposed to high-energy radiation, for example UV light, electron or gamma radiation, in addition to the heating described, once the lamination has been completed. being UV Use light in conjunction with subbing layers that contain photoinitiators.

The lamination, preferably on both sides of the information carrier, is expediently carried out continuously by bringing the individual information carriers together onto the foils which run off supply rolls and are provided with the adhesive layer. The parts containing the information carriers can then be punched out of the resulting band-shaped laminate, the welded film being cut off at a distance of approximately 1 to 2 mm from the edge of the information carrier, depending on the thickness of the information carrier.

An all-round closed wrapping of the information carrier is obtained, which makes subsequent edge welding unnecessary. Of course, discontinuous lamination using sheet-shaped pieces of film leads to the same results.

The documents described are excellent forgery-proof. The gelatin layers of the information carrier composed in the manner according to the invention surprisingly strengthen the bond between films and information carrier. Even with the help of heat and / or solvents, the document can no longer be separated without completely destroying the information carrier.

Another important and surprising advantage of the identification documents or ID cards according to the invention with polyalkyleneimine adhesive layers lies in the excellent flatness. It is precisely in this respect that the documents according to the invention are better known.

example 1

100 g of an aqueous 2% by weight polyethyleneimine solution were mixed with 0.1 g of glacial acetic acid and 2 ml of an aqueous 40% by weight formaldehyde solution and then applied to a polyethylene film. The surface of the polyethylene film was exposed to corona radiation before casting. The dried layer contained 0.1 g polyethyleneimine per m ² .

A conventional photographic paper was used as information carrier, the layer carrier of which consisted of paper laminated on both sides with polyethylene, which had an m ² weight of approximately 120 g. The softening point of the polyethylene of the support was 110 ° C. After exposure to corona on both sides, the support was equipped with a light-sensitive silver halide gelatin emulsion layer and with a gelatin-containing protective layer and back layer.

The silver halide emulsion layer was based on a photographic black and white emulsion of the usual composition. The layer contained 3.5 g of gelatin and 1.2 g of polyethyl acrylate (particle size about 0.05 11 m ⁾ per m ² , plus the usual additives, for example wetting agents and hardening agents. The layer thickness of the dry layer was 4.7 µm. A protective layer was placed over the silver halide emulsion layer and contained 1.2 g of gelatin, 0.45 g of polyethyl acrylate and 0.3 g of polyacrylonitrile with a particle size of approximately 3 11 m per m ² . The thickness of the dry layer was 1.95 11m.

A layer was applied to the back of the support which contained 1.8 g of gelatin, 0.65 g of polyethyl acrylate, 0.45 g of polyacrylonitrile and 0.005 g of potassium nitrate per m ² . The thickness of the dry layer was 2.9 ₁₁ m.

An image of the card holder along with the corresponding information was now exposed on the information carrier and the material developed, fixed and, after drying, printed on both sides with a guilloche pattern.

The information carrier with the photographic and printing-related identification features was placed between 2 of the above-mentioned polyethylene films, the softening point of which was approximately 122 ° C., so that the adhesive layers of the films came into contact with the two surfaces of the information carrier and the films about 1 mm over the edge of the information carrier protruded. The package was then passed between two rollers heated to 90 ° C. and pressed together with a pressure of approximately 1.5 kp / cm ² .

After the document had cooled down, the polyethylene films were so firmly attached to the information carrier that when trying to separate the document after the edge bonds had been cut off while heated (approx. 100 ° C), the paper support of the information carrier was destroyed, but its remnants were removed from the films were recorded, which were also irreversibly stretched. The connection between the film and the surface of the information carrier could not be broken even by treatment with hot water or with solvents such as chloroform, gasoline, acetic acid or dilute hydrochloric acid.

Example 2

The adhesive layer solution described in Example 1 was applied to a corona-irradiated polyethylene terephthalate film and this was glued between two rollers heated to 90 ° C. under a pressure of 5 kp / cm ² with a likewise corona-irradiated polyethylene film, whereby a composite film was formed.

A photographic film material was used as the information carrier, which contained a layer support provided with the usual substrate layers and consisting of cellulose triacetate pigmented with titanium dioxide, a silver halide gelatin emulsion layer, a gelatin protective layer lying over this and a gelatin backing layer.

The composition of the three gelatin layers corresponded to that given in Example 1.

A picture of the card holder along with the corresponding information was exposed on this information carrier, the material developed, fixed, dried and finally printed on both sides with a guilloche pattern.

To produce the document, the polyethylene surface of the composite film was coated with the same adhesive layer composition already used in the production of the composite film and laminated to the information carrier as described in Example 1.

The result was an ID card with excellent flatness. The ID document can no longer be separated without completely destroying the photographic material used as the information carrier.

Example 3

Example 2 was repeated with the difference that in the three gelatin layers, the polyethyl acrylate was replaced by the corresponding amount of gelatin.

The adhesion of the foils to the surface of the information carrier was insufficient. Under the effect of water vapor or solvent vapors, the surface of the information carrier could be exposed without any significant damage.

Claims (7)

1. A tamper-proof document consisting of an information carrier in the form of a photographic material carrying information and covered on one or both sides with at least one transparent film laminated thereto by means of an adhesive layer, the information carrier having at least one gelatine layer carrying a photographic silver or dye image, optionally an outer gelatine-containing protective layer applied to the emulsion side, and an outer gelatine-containing layer applied to the back, and at least the outer layers of the gelatine-containing layers contain particles, of a size smaller than 0,1 µm, of a homo- or copolymer of an acrylic acid or/and methacrylic acid ester and a matting agent, the content of the polymer being 10-50% by weight and of the matting agent bein 15-40% by weight, based on the gelatine content of the layers.

2. A document according to Claim 1, characterised in that the acrylic acid ester and the methacrylic acid ester are a C₁-C₁₂-alkyl acrylate and a C₁-C₁₂-alkyl methacrylate.

3. A document according to Claims 1 and 2, characterised in that the homo- or copolymer particles have a size of 0,01 to 0,07 µm.

4. A document according to Claim 1, characterised in that the matting agent has a particle size of 2,5 to 3,5 µm.

5. A document according to Claim 1, characterised in that the matting agent is polyacrylonitrile.

6. A document according to Claim 1, characterised in that the gelatine-containing layers of the information carrier contain, based on the gelatine content of the layer, 25 to 40% by weight of the homo- or copolymer.

7. A document according to Claim 1, characterised in that the gelatine-containing layers of the inforamtion carrier contain, based on the gelatine content of the layer, 20 to 30% by weight of the matting agent.