WO2015040183A1

WO2015040183A1 - Semifinished product, security document, and method for producing such security documents having a uv-excitable luminescent security print

Info

Publication number: WO2015040183A1
Application number: PCT/EP2014/070039
Authority: WO
Inventors: Jens Ehreke; Alexander MOMBRÉE; Hanna Kindler; Michael Knebel; André LEOPOLD; Per KRÜGER; Peter Paul; Thomas Bitzer
Original assignee: Bundesdruckerei Gmbh
Priority date: 2013-09-19
Filing date: 2014-09-19
Publication date: 2015-03-26
Also published as: DE102013218861A1

Abstract

The invention relates to a method for producing a semifinished product (200), to a semifinished product (200), to a method for producing a security document (300), and to a security document (300) having a security print (220) that shows a luminescent colored image under UV excitation (230). A method (10) for producing a semifinished product (200) for a security document (300) is proposed, wherein the semifinished product (200) has a high-resolution security print (20), which gives a multi-colored impression in the visible wavelength range under UV excitation, comprising the following steps: providing a substrate (210); providing at least two color printing compositions, which show a colored luminescence in the visible wavelength range under UV excitation (230) in the printed state, wherein the at least two color printing compositions have different luminescence spectra under UV excitation in the printed state, which different luminescence spectra make different color impressions; performing a high-resolution printing method in order to print colored information components of the security print (220) to be produced, by means of the at least two color printing compositions provided, wherein additionally an absorber printing composition is provided, which comprises a UV absorber, which shows no luminescence in the visible wavelength range under the UV excitation (230), and black information components of the security print (220) are printed by means of the absorber printing composition.

Description

Semi-finished product, security document and method for producing such with a UV-stimulable luminescence safety printing

The invention relates to a method for producing a semifinished product for a

Security document with a security printing, which produces a multicolored impression upon UV excitation in the visible wavelength range, such a semifinished product and a security document produced with such a semifinished product.

From the prior art it is known to introduce so-called hidden security features in security documents. Security features are those features that imitate, falsify, duplicate,

make unauthorized production or the like at least complicate or impossible. In addition, security features serve to verify the authenticity of a security document to which these or these are incorporated. One

Security document is thus in each case a document which at least one

Security feature includes. Security documents include, for example

Passports, identity cards, driver's licenses, access cards, visas, banknotes, securities, but also against counterfeited labels and / or tickets or the like.

To the hidden features, i. Such features, which are imperceptible and / or verifiable without a technical aid, also include so-called luminescence images or prints in general, which are carried out with luminescent colors. After excitation of the luminescence, for example by means of high-energy, electromagnetic radiation, for example UV radiation, luminescence light becomes visible in a visible wavelength range. From the prior art

Substances and colorants are known which show no absorption in the visible wavelength range, i. are transparent in the printed state on a transparent substrate, but show a visible perceptible colored luminescence upon excitation of the luminescence, for example by means of UV radiation.

Hersch et al., In Proceedings Sigg Graph 2007, ACM Trans. Graph., Vol. 26, No. 3, Article 75 (July 2007), 9 pages, are in the article "Color images visible under UV-light" Such UV prints are described, for example, problems of the Generation of possible monochromatic individual colors treated to produce a full-color impression, which results from a color addition of the luminescent light differently colored pixels.

Regardless of these problems of producing a particular color impression via the color addition of different luminescent pixels, it has been found in the prior art that high resolution security prints, which are colorful, i.

store different color impressions, print information store a blurred and slightly blurred impression in an observer when the luminescence image is viewed under UV excitation. The achievable detail sharpness and so-called drawing is significantly worse than that of the used

Print resolution for printing the individual monochromatic colors generating pixels is to be expected.

The invention is thus based on the technical object of providing a method for producing a semifinished product, a semifinished product and a security document produced with such a semifinished product which have a security printing which produces a colored impression on UV excitation and an improved drawing and sharpness of detail show objects known in the art.

The invention is based on the idea to achieve an improved drawing and sharpness of detail in that stronger contrast transitions and in particular also black components of colored security prints are improved. For this purpose, it is provided, in addition to the printing preparations, which in each case in the printed state a color impression in luminescence excitation in the visible

Wavelength range and suitable for forming different color impressions in cooperation with other color compositions in the context of a color addition of the emitted luminescent light to print a printing preparation which shows a UV absorption, but does not cause luminescence in the visible wavelength range. It has been shown that this improved

Representations of black components and an increased contrast and, consequently, an improved drawing and detail sharpness is possible. Overall, luminescence images produced in this way show a significantly improved color brilliance compared with the images known from the prior art. In particular, a method for producing a semifinished product for a security document is proposed, wherein the semifinished product has a high resolution

Having security printing that produces a multicolor impression upon UV excitation in the visible wavelength range, comprising the steps of: providing a substrate; Providing at least two color printing compositions which are described in U.S. Pat

printed state in UV excitation in each case in the visible wavelength range show a colored luminescence, wherein the at least two color printing compositions in the printed state at UV excitation have different Lumineszenzspektren that cause different color impressions; Running a

high-resolution printing process for printing colored

Comprising information components of the security print to be produced with the at least two color printing compositions provided, wherein it is contemplated that an absorber printing composition comprising a UV absorber exhibiting no luminescence in the visible wavelength range is additionally provided, and black information components with the absorber printing composition of

Security printing to be printed.

Furthermore, a semifinished product for a security document is proposed which comprises: a substrate on which a high-resolution security print is made with at least two different color print compositions, wherein the at least two different color print compositions exhibit colored luminescence in the printed state upon UV excitation, and different

Have luminescence spectra in the visible wavelength range, so that they produce different color impressions in the visible wavelength range; wherein the colored information components of the security printing are printed with the at least two color printing compositions, wherein it is provided that the

Security printing additionally comprises black information components printed by means of an absorber printing composition comprising a UV absorber which shows no luminescence in the visible wavelength range.

Finally, a security document with a high-resolution security print is proposed, which produces a multicolored impression on UV excitation in the visible wavelength range, it being provided that a semifinished product described above, which comprises a substrate provided with the security printing, joined together with further substrate layers to form a security document body becomes. All of these embodiments have the advantage that a security printing is produced or contained in them, which exhibit a significantly improved color brilliance of the image which is visible in the visible wavelength range when reproduced during UV excitation and permits a significantly improved drawing and detail sharpness. This means finer lines can be displayed graphically better.

definitions

As printing composition, any ink or printing ink is designated, which can be printed by means of a printing device.

A color printing composition is a composition which, when printed, produces a colored impression, at least when exposed to ultraviolet light in the visible wavelength range; Light emitted in the visible wavelength range.

An absorber printing composition is a composition which absorbs light in the UV wavelength range but does not absorb light in the visible

Has wavelength range and possibly even when excited with UV radiation also shows an absorption in the visible wavelength range.

As used in the printed state, mistype printing compositions and absorber printing compositions are referred to as transparent, which in the visible wavelength range show no absorption or remission in the visible

Wavelength range show, provided that they are excited or irradiated with light in the visible wavelength spectrum and not at the same time there is a UV excitation.

Colorants are those components of a printing composition which are responsible for the color of the printing composition in the printed state.

UV light refers to that light which, on the high-energy side, adjoins the visible spectral range and is not directly visually perceptible to a human observer. As colored or full color, a graphical representation of information is called when it causes several different color impressions in a human observer. The display area thus has locally different remission or emission spectra.

Due to the laws of color addition and color subtraction, colorful or full-color information comprising a variety of different color impressions can be formed with a small number of colorants or printing compositions. For example, printing compositions which in the printed color state produce the color impressions cyan, magenta and yellow suffice to form the majority of the human-perceivable colors or color impressions. The colors that span such a color space are called primary colors and the spanned color space is called gamut. To help with the help of

To create luminescent colorants colorful graphic representations, you need, for example, the color-printing composition that luminesce accordingly in the colors red, blue and green.

Preferred embodiments

In order to hide the information stored in the security print, in one embodiment, providing the at least two color print compositions and the absorber print composition comprises selecting or making the print compositions with colorants and absorbers which are in the printed state in the visible wavelength range are transparent. A security print made with such color print compositions is only visible on UV excitation.

In order to make it possible to produce different colors and shades, in a preferred embodiment of the invention it is provided that the provision of the at least two color printing compositions comprises selecting or producing the color printing composition with colorants which in the printed state upon UV excitation emit in the visible wavelength range only light of a wavelength or a narrow wavelength range. This creates the possibility, via a relative concentration of the different color impressions causing colorant or color-print compositions, a on the Color addition resulting in mixing color in the color impression in UV excitation to influence and select. Preferably, the absorber printing composition is also formed so that it is also completely transparent with exclusive excitation or irradiation in the visible wavelength range.

In order to be able to span a full-color gamut and thus to be able to realize image information representing a full-color image in the security printing, it is provided in one embodiment that at least one third color printing composition is selected and provided with colorants or alternatively prepared with colorants, each in the printed state when UV excitation only light in a wavelength or a narrow wavelength range in

emitted visible wavelength range and wherein the at least one third color printing composition and the at least two color printing compositions are selected or prepared so that by the three wavelengths or the three narrow wavelength ranges a gamut is spanned, which allows a full-color information reproduction.

It has been found that the best results can be obtained when the absorber printing composition is last printed on the otherwise already printed color information. Since in a high-resolution printing, for example, a security printing, which is produced by an inkjet printing process, the individual color components generating printing pixels are not printed completely adjacent to each other, but also partially overlapping, it proved to be useful, the UV absorber shares later then provide reliable absorption and no luminescence in their print area.

In a preferred embodiment, the individual color printing compositions and the absorber printing composition are applied side by side and not overlapping. This allows optimal color control.

In a further development of the method for producing a semifinished product, one obtains

A method of producing a security document by providing, in addition to the semifinished product, at least one further substrate layer, preferably several further substrate layers, and assembling it with the semifinished product provided with the security print and the semifinished product with the security print provided substrate layer and the remaining substrate layers zusammenfügt to a document body of the security document, for example in a high-pressure high-temperature lamination process.

The invention will be explained in more detail with reference to a drawing.

Hereby show:

1 is a schematic flow diagram of a method for generating a

Semi-finished product;

FIG. 2 is a flowchart for generating a security document; FIG.

Fig. 3 is a schematic representation of a semifinished product;

4 is an exploded view of a security document;

Fig. 5 is a schematic view of a security document under UV excitation;

and

6 is a schematic view of a security document without UV

Stimulation.

FIG. 1 schematically shows a flow chart of a method 10 for producing a semifinished product. In a first method step, a substrate 12 is provided. The substrate may be a paper substrate, but may also be a plastic-based substrate, for example a plastic film, in particular

Polycarbonate, PVC, ABS or similar material. Preferably, it will be a transparent substrate layer.

At least two, but preferably three or even six, color printing compositions are provided which, when printed with UV light, emit or suitably emit light of a wavelength or a narrow wavelength range are, in interaction with each other to produce different colors due to the color addition of the emitted luminescent light.

Also at the same time or subsequently, at least one absorber printing composition is provided or prepared 16 which, although a printed condition exhibits absorption in the UV range, does not exhibit luminescence emission in the visible wavelength range. The color components of the information of a security printing can then be printed on the substrate with the color printing compositions 20. In this case, first a print information can be recorded. 22. This is then preferably decomposed into different print separations 24, which are respectively assigned to one of the color print compositions at which positions, and optionally in what quantity, a corresponding color printing composition is printed on the substrate. Subsequently, the actual printing of the color printing compositions according to the

Color print separations, for example, with an ink jet printer instead of 26. In one embodiment, the ink compositions are not printed overlapping. Subsequently, the black components of the printing information of the

Security pressure on the substrate with the absorber printing composition

For this purpose, a reprint for the black components of the printing information can be determined again 32 and then the actual printing again done by means of an inkjet printer according to the determined pressure separation with the absorber pressure composition 34. The absorber pressure composition in one embodiment is not overlapping with the color printing compositions. Subsequently, the semi-finished is finished.

FIG. 2 shows a schematic flow diagram for a method for producing a security document. The method 100 comprises as a first method step the production and / or provision of a semifinished product 1 10 according to the method according to FIG. 1. In addition, one or more further substrate layers are provided. 12. The semifinished product and the further substrate layers, which are preferably made of the same plastic material as those provided with the security print

Substrate layer of the semifinished product, to a substrate layer stack

compiled 1 14 and then joined together in a high pressure, high temperature lamination process to form a document body 16. During the manufacture and / or provision of the substrate layers of the semifinished product and also between the method steps described here can more

Security features are integrated and incorporated into the substrate layers and / or the security document body 1 18.

FIG. 3 shows a schematic view of a semifinished product 200. The semifinished product comprises a substrate layer 210 on which a security print 220 is printed. In the schematic representation, the semifinished product 200 is illuminated with UV radiation 230 so that the colored security print 220 is visible as a luminescent image. In the illustrated case, the security print 220 shows a facial image. If the UV excitation is set, then the security pressure is not seen, since the for the production of the

Security printing 220 used printing compositions without excitation with UV light are transparent. In a section 240 it can be seen that the security print 220 is composed of different pixels 250-r, 250-b, 250-g and 250-a. The following letters r, b, g and a stand for the color components r = red, g = green, b = blue emitted under UV excitation and the letter a for the absorption of the UV light without an emission of visible light. Through this structure of the

Security Printing 220 can be achieved a higher color brilliance and improved drawing and detail sharpness. Here, the pixels 250-a printed with the absorber printing composition are post-printed, and partly printed over the print pixels 250-r, 250-b, 250-g printed with the color-print compositions. The detail 240 shows only by way of example and schematically some printing pixels 250.

In a second section 260, an area is shown enlarged, in which an image component is formed black. Here, therefore, there occurs a surface portion 270 having almost only printing pixels 250-a printed with the absorber printing composition. When UV excitation, this surface section is black

perceived. Again, only exemplary and schematically some print pixels 250 are shown.

In another embodiment, the print pixels are all non-overlapping. As a result, a very good color control and a very high contrast sharpness and very good drawing is achieved.

FIG. 4 schematically shows an exploded view of a security document 300 into which the semi-finished product 200 and two further substrate layers 310 and 320 are integrated. The semifinished product 200 is disposed between these further substrate layers 310 and 320 and is laminated therewith to a security document body 400.

This security document body 300 is shown in FIG. 5 in the state in which a UV excitation 230 takes place. The security pressure 220 is again inside the

Security document 400 to recognize.

In Fig. 6, the same security document 300 is shown, but without UV excitation. The security pressure 220 can not be seen here, since the used

Printing compositions or the hereby printed pixels in the visible

Wavelength range without UV excitation are transparent.

As the material for the luminescent color printing compositions, water-soluble acrylates having a polyurethane content can be used as the binder. As wetting agents, glycols or glycerols are preferably added. The colorants used are preferably nanoscale organic or inorganic luminophores.

In particular, so-called pigment slurries with a water content of about 50% can be used and provide a basis for an ink. To such a pigment slurry is preferably added a cationic acrylic resin solution, as marketed, for example, under the trademark WorleeCryl 8721 by Worlee-Chemie GmbH in Lauenburg, Germany, as rub-on binders for organic and inorganic pigments. Thus prepared printing compositions are particularly useful for use in an ink jet printing system. The prerequisite is that the pigment sizes are chosen as small as possible, preferably nanoscale.

Suitable absorbers are marketed under the name "TINUVIN" by BASF, Ludwigshafen, Germany.

If a plastic surface is printed, a thermal fixation immediately after printing is advantageous. This fixation is carried out at 40 ° C to 80 ° C for a period of about 1 to 3 minutes. This ensures that solvents evaporate from the pressure composition used. The printed preparation, For example, a pixel is "gelled" and is thus applied in a spot-sharp manner to the plastic substrate, in any case avoiding thermoplastic deformation and thermoplastic softening of the printed substrate layer

Drying step can also be carried out as a UV drying step, during which UV radiation is irradiated onto the printed substrate to be dried.

In addition, a post-drying may be advantageous, are expelled in the water and other difficult evaporating solvent from the printed preparation. If the printed substrate layer is subsequently joined together with further substrate layers in a lamination process, secondary drying can generally be omitted.

In addition, in some embodiments, in the ultraviolet spectral region, luminescent substances may be introduced into a semifinished product, for example as background printing, which also has a different physical effect than that of the present invention

Radiation of light can be stimulated to luminescence. By way of example, electroluminescent substances may be mentioned here. It is also possible to introduce substances which exhibit a so-called "up-conversion", that is to say absorb light from the visible wavelength range and emit light in the UV wavelength range Such substances can be used as light source for a light source as described above

Security print with a UV luminescence image serve.

If the printed substrate is not inserted into a laminate as an inner layer, it is advantageous to apply a protective film or a lacquer, for example a scratch-resistant lacquer.

Use of a UV-transparent transparent security print with a colored UV luminescent image may also be used in security documents to replicate information otherwise encoded in the security document. For example, the passport number of a passport book may be printed on each page in the form of such security printing. The affiliation of the passport pages to a passport card designed and incorporated as a plastic laminate can thus be easily verified on UV excitation. It will be apparent to those skilled in the art that substantially exemplary embodiments of the invention are described here. The features described in the various embodiments may be combined together to carry out the invention.

LIST OF REFERENCE NUMBERS

10 Method for producing a semifinished product

12 - 34 Process steps for the production of a semi-finished product

100 Method for producing a security document

1 10 - 1 18 Procedural steps to produce a security document

200 semi-finished products

210 substrate layer

220 security printing

230 UV light excitation

240 section

250-r pixel, which emits red luminescent light

250-g pixel, which emits green luminescent light

250-b pixel that emits blue luminescent light

250-a pixel, which absorbs UV light but does not emit visible light

260 second section

270 area section

300 security document

310 substrate layer

320 substrate layer

400 security document bodies

Claims

claims

1 . A method (10) for producing a semifinished product (200) for a security document (300), wherein the semifinished product (200) has a high-resolution security print (20) which produces a multicolored impression on UV excitation (230) in the visible wavelength range the steps:

Providing a substrate (210);

Providing at least two color printing compositions which in the printed state on UV excitation (230) in the visible wavelength range, a colored luminescence, said at least two color printing compositions in the printed state at UV excitation (230) have different Lumineszenzspektren, the different

Cause color impressions;

Carrying out a high-resolution printing process for printing colored information components of the security print (220) to be produced with the at least two color printing compositions provided,

characterized in that

in addition, there is provided an absorber printing composition comprising a UV absorber which does not exhibit luminescence in the visible wavelength range upon UV excitation (230), and printing black information components of the security print (220) with the absorber printing composition.

The method (10) of claim 1, characterized in that the providing of the at least two color printing compositions comprises selecting or producing the color printing composition with colorants which are transparent in the printed state in a visible wavelength range.

3. The method (10) according to claim 1 or 2, characterized in that the

Providing the at least two color printing compositions comprises selecting or producing the color printing composition with colorants which emit in the printed state on UV excitation only light of a wavelength or a narrow wavelength range in the visible wavelength range.

A method (10) according to claim 3, characterized in that at least one third color printing composition is selected and provided with colorants or, alternatively, prepared with colorants, each in the as-printed condition upon UV excitation, only light of one wavelength or of a narrow one

Emitted wavelength range in the visible wavelength range and wherein the at least one third color printing composition and the at least two color printing compositions are selected or prepared so that by the three wavelengths or the three narrow wavelength ranges a gamut is spanned, which allows a full-color information reproduction.

5. The method (10) according to any one of the preceding claims, characterized

characterized in that the absorber printing composition is last printed on the otherwise already printed color information.

6. A method of producing a security document (300) comprising

Steps,

Providing a semifinished product (200) produced according to the method of claims 1 to 5 or producing the semifinished product (200) with a method of claims 1 to 5, so that a substrate layer (210) is present, which comprises a security print (220) UV excitation in the visible

Wavelength range causes a multi-colored color impression;

Collating the substrate layer (210) provided with the security print (220) with further substrate layers (310, 320) and

Assembling the substrate layer (210) provided with the security print (220) with the further substrate layers (310, 320) to a document body (400) of the security document (300).

7. Semifinished product (200) for a security document (300)

a substrate (210) on which a high-resolution security printing (220) is carried out with at least two different color printing compositions, wherein the at least two different color printing compositions exhibit colored luminescence in the printed state upon UV excitation (230) and different luminescence spectra in the visible wavelength range, so that they are visible Wavelength range produce different color impressions; wherein the colored information components of the security printing (220) are printed with the at least two color printing compositions,

characterized in that

the security print (220) additionally comprises black information components printed by means of an absorber printing composition comprising a UV absorber but no visible luminescence

Wavelength range shows.

8. Semi-finished product (200) according to claim 7, characterized in that the

Security pressure (220) when illuminated with light in the visible

Wavelength range is transparent.

9. Semi-finished product (200) according to claim 7 or 8, characterized in that the

Security print (220) is printed with at least one further color printing composition in addition to the at least two different color printing compositions, wherein the at least one third color printing composition and the at least two color printing compositions each have only a narrow band luminescence emission in the visible wavelength range and together spanning full color gamut.

10. Semifinished product (200) according to one of the preceding claims, characterized

characterized in that the absorber printing composition is at least partially over the color information printed with the at least two different color printing composition or over at least two

different color printing composition and the at least one further color printing composition printed color information is printed.

1 1. Security document (300) with a high resolution security print (220), which on UV excitation (230) in the visible wavelength range

multicolored impression, characterized in that the

Security document (300) comprises a security body (400), wherein a semifinished product (200) according to any one of claims 7 to 10, which one with the

Security print (220) provided substrate (210), with further Substrate layers (310, 320) is joined to the security document body (400).