Printed image

Abstract

The present invention relates to a printed image comprising flake-form effect pigments which has striking matt/gloss effects, to a process for the production of a printed image of this type, and to the use thereof, in particular in security printing.

Claims

1. A printed image comprising at least two printed area units on a substrate, wherein each of the area units comprises flake-form effect pigments and a binder, a first printed area unit comprising solidified area of a first printing ink comprising a first flake-form effect pigment, said first flake-form effect pigment being based on coated support flakes and having an outermost layer consisting of a non-metallic, inorganic material, and a second printed area unit comprising a solidified area of a second printing ink comprising a second flake-form effect pigment, which is based on coated support flakes and has an outermost layer comprising an organic surface modifier, and wherein said first and second printed area units are visible simultaneously to the naked eye and optically distinguishable from one another when viewing the substrate on a surface carrying the printed image at any viewing angle and have different flop indicies from one another, said first flake-form effect pigments are arranged in random distribution in the first printed area unit and said second flake-form effect pigments are aligned parallel to the substrate at the surface of the second printed area unit.

2. The printed image according to claim 1, wherein the first and second area unit are directly adjacent to one another.

3. The printed image according to claim 1, wherein the organic surface modifier comprises organofunctional siloxanes.

4. The printed image according to claim 3, wherein the organo-functional siloxanes contain fluoroalkyl groups and aminoalkyl groups.

5. The printed image according to claim 1, wherein the second flake-form effect pigment below the outer layer comprising an organic surface modifier has a layer comprising a non-metallic, inorganic material.

6. The printed image according to claim 1, wherein the first and second flake-form effect pigment differ merely through the outer layer comprising an organic surface modifier on the second flake-form effect pigment.

7. The printed image according to claim 1, wherein the first and second flake-form effect pigment are pearlescent pigments, interference pigments, metal-effect pigments or optically variable pigments.

8. The printed image according to claim 7, wherein the first and/or second flake-form effect pigments also have magnetic, electrically conductive or luminescent properties.

9. The printed image according to claim 1, said image having a laser marking.

10. The printed image according to claim 9, wherein the laser marking is located on the first and/or second area unit.

11. The printed image according to claim 1, wherein the substrate is paper, cardboard, wallpaper, tissue material, plastic, metal, ceramic, glass, wood, textile material or a composite material comprising two or more of the above-mentioned materials.

12. The printed image according to claim 11, wherein the paper is banknote paper.

13. The process according to claim 12, wherein the first and/or second printing ink is a screen printing ink, a gravure printing ink, a flexographic printing ink or an intaglio printing ink.

14. A process for the production of a printed image according to claim 1, comprising applying to a substrate a first printing ink, comprising a first flake-form effect pigment, which is based on a coated support flake and has an outermost layer consisting of a non-metallic, inorganic material, and a binder, forming a solidified first area unit of a printed image, and applying to the substrate a second printing ink, comprising a second flake-form effect pigment, which is based on a coated support flake and has an outermost layer comprising an organic surface modifier, and a binder forming a solidified second area unit of a printed image, where the first and second area units are applied to the substrate at a separation from one another so that they are simultaneously visible to the naked eye and optically distinguishable from one another when viewing the substrate on a surface carrying the printed image at any viewing angle, and where the first and second area units have different flop indicies from one another.

15. The process according to claim 14, wherein the first and second area unit are applied to the substrate directly adjacent to one another.

16. The process according to claim 14, wherein the outer layer of the second effect pigment comprises organofunctional siloxanes.

17. The process according to claim 16, wherein the organofunctional siloxanes are siloxanes which contain fluoroalkyl groups and aminoalkyl groups.

18. The process according to claim 14, wherein the first and/or second area unit are provided with a laser marking.

19. A product having a decoration element, functional element or security feature, said decoration element, functional element or security feature comprising a printed image according to claim 1.

20. The product according to claim 19, that is banknotes, cheques, credit cards, shares, passports, identity documents, driving licences, entry tickets, revenue stamps, labels, packaging materials or seals.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) FIGS. 1-5 show various design examples of the printed image in accordance with the present invention. FIGS. 4a and 5a show cross sections along the respective line A-B of FIGS. 4 and 5.

EXAMPLE 1

(2) Organic Surface Modification

(3) 1000 g of Colorcrypt Intaglio Gold (product from Merck KGaA) are prewetted with 100 g of water in a heatable mixer. 35 g of Dynasylan F8815 (Evonik) are added, followed by 100 g of a 2.5% ammonia solution. The batch is mixed at 60 C. for 30 minutes and freed from water at 120 C. The product is subsequently sieved using a mesh width of 63 m.

EXAMPLE 2

(4) Organic Surface Modification

(5) 150 g of each of Colorcrypt M Silver, Colorcrypt M Gold and Colorcrypt M Bronze (products from Merck KGaA) are suspended in 1.5 l of water and heated to 55 C. with stirring. A pH of 4 is set using hydrochloric acid, and 6.68% by weight, based on the pigment employed, of Dynasylan F8815 (Evonik) are added dropwise over the course of 18 minutes, and the mixture is stirred for a further 30 min. A pH of 8 is set using sodium hydroxide solution over the course of 22 minutes, and the mixture is stirred for a further 60 minutes. After filtration, the products are freed from water at 150 and sieved using a mesh width of 40 m.

(6) The surface energy of the effect pigments surface-modified in Example 1 and 2 is determined by the sessile drop method using the measurement liquids water, 1,2-diiodomethane, benzyl alcohol and 1,2 pentanediol using a Krss DAS 100 measuring instrument at 22-24 C. 5 l drops are placed semi-automatically on a pigment layer by means of the Krss DAS 3, release 1.7.1 control and evaluation software, and the contact angles between drop and pigment layer surface are measured. The evaluation is carried out by the Owens, Wendt, Rabel and Kaelble (OWRK) method by means of the above-mentioned software.

(7) The total surface energies determined for the coated pigments exhibit a drastic reduction from 48-58 mN/m to <10 mN/m (Table 1) after surface modification has been carried out, where the polar fraction of the total surface energies is eliminated virtually completely by the siloxane oligomer coating and only a dispersive fraction remains (Table 2).

(8) (all effect pigments denoted by M here are magnetisable)

(9) TABLE-US-00001 TABLE 1 Total surface energies of the uncoated/coated pigments by the OWRK method; Total surface energy of the uncoated Pigment pigment [mN/m] coated pigment*.sup.) [mN/m] Colorcrypt M Gold 51.4 7.2 Colorcrypt Intaglio Gold 58.0 4.9 Colorcrypt M Silver 58.0 3.0 Colorcrypt M Bronze 48.5 5.3 *.sup.)all pigments were coated with 1% by weight of Dynasylan F8815, apart from Colorcrypt M Gold with 0.5% by weight

(10) TABLE-US-00002 TABLE 2 Dispersive and polar fraction of the total surface energies of the uncoated/ coated pigments; Dispersive Polar fraction Pigment fraction [mN/m] [mN/m] Colorcrypt M Gold uncoated 32.1 19.3 Colorcrypt M Gold coated*.sup.) 7.2 0.0 Colorcrypt Intaglio Gold uncoated 27.6 30.4 Colorcrypt Intaglio Gold coated*.sup.) 4.8 0.1 Colorcrypt M Silver uncoated 34.0 24.0 Colorcrypt M Silver coated*.sup.) 3.0 0.0 Colorcrypt M Bronze uncoated 33.3 15.2 Colorcrypt M Bronze coated*.sup.) 5.0 0.3 *.sup.)all pigments were coated with 1% by weight of Dynasylan F8815, apart from Colorcrypt M Gold with 0.5% by weight

EXAMPLE 3

(11) Production of Printed Layers

(12) 15% by weight of Colorcrypt M Gold (surface-modified or untreated) 85% by weight of screen-printing binder, e.g. WEILBURGER UV 363030

(13) The untreated or surface-modified pigments are in each case stirred separately into the screen-printing binder under gentle conditions and printed onto two area units located alongside one another on paper substrates using a 64T screen. The UV binder is subsequently crosslinked using a Hoenle UV lamp.

(14) Printing inks comprising Colorcrypt M Silver, Colorcrypt M Bronze or Colorcrypt Intaglio Gold are printed analogously.

(15) The lightness values L* of the printed layers at the measurement angles of 15, 45 and 110 are determined by means of a BykGardner BykMac colour measuring instrument, and the flop index is calculated as follows:

(16) $\mathrm{Flop}\mathrm{index}=\frac{2.69{\left(L_{{15}^{}}^{*}-L_{{110}^{}}^{*}\right)}^{1.11}}{{\left(L_{{45}^{}}^{*}\right)}^{0.86}}$

(17) Table 3 shows the flop indices for the lightness flop of the printed layers comprising coated and uncoated pigments, where it becomes clear that the flop index increases significantly in the case of a suitable combination of binder and coated pigment.

(18) The most suitable binders having the greatest increase in the flop index are WEILBURGER UV 363030 and G&D UV 4800 having flop indices of 8-11 (pure metal pigments have a flop index of 15-17), where the pigments Colorcrypt M Gold and Bronze exhibit the greatest effect.

(19) TABLE-US-00003 TABLE 3 Flop index and flop index difference of the uncoated/coated pigments in various UV binder systems Flop index of the uncoat- coated ed pig- Flop index Binder Pigment pigment ment*.sup.) difference WEIL- Colorcrypt M Gold 3.3 8.3 5.0 BURGER UV 363030 RUCO UV Colorcrypt M Gold 3.8 6.4 2.6 960 161 Colorcrypt Intaglio Gold 1.9 2.8 0.9 Colorcrypt M Silver 4.2 6.7 2.5 Colorcrypt M Bronze 3.5 7.8 4.3 PRLL UV Colorcrypt M Gold 3.3 7.3 4.0 57966 Colorcrypt Intaglio Gold 2.1 2.6 0.5 Colorcrypt M Silver 4.0 6.7 2.7 Colorcrypt M Bronze 2.8 6.8 4.0 G&D UV Colorcrypt M Gold 3.9 9.8 5.9 4800 Colorcrypt Intaglio Gold 1.8 5.0 3.2 Colorcrypt M Silver 5.3 9.3 4.0 Colorcrypt M Bronze 3.9 11.4 7.5 *.sup.)all pigments were coated with 1% by weight of Dynasylan F8815, apart from Colorcrypt M Gold with 0.5% by weight

(20) The lightness L.sub.15 at a measurement angle of 15, i.e. 15 away from the specular angle, is determined using the BykGardner BykMac colour measuring instrument (Table 4). It is found that the printed layers comprising coated pigments have significantly higher lightness values than the printed layers comprising uncoated pigments even at an angle which is 15 away from the actual specular angle, where the combination with the binders WEILBURGER UV 363030 and G&D UV 4800 again exhibit the greatest increases here.

(21) TABLE-US-00004 TABLE 4 Lightness L*.sub.15 of the uncoated/coated pigments in various UV binder systems L*.sub.15 uncoat- coated ed pig- L*.sub.15 Binder Pigment pigment ment*.sup.) difference WEIL- Colorcrypt M Gold 63 93 30 BURGER UV 363030 RUCO UV Colorcrypt M Gold 69 79 10 960 161 Colorcrypt Intaglio Gold 76 80 4 Colorcrypt M Silver 60 74 14 Colorcrypt M Bronze 64 80 16 PRLL UV Colorcrypt M Gold 68 85 17 57966 Colorcrypt Intaglio Gold 78 81 3 Colorcrypt M Silver 62 76 14 Colorcrypt M Bronze 58 76 18 G&D UV Colorcrypt M Gold 69 98 29 4800 Colorcrypt Intaglio Gold 75 93 18 Colorcrypt M Silver 67 83 16 Colorcrypt M Bronze 63 93 30 *.sup.)all pigments were coated with 1% by weight of Dynasylan F8815, apart from Colorcrypt M Gold with 0.5% by weight

EXAMPLE 4

(22) Production of Lasered Printed Layers

(23) The multi-area printed images printed in accordance with Example 3 in any desired design (see FIGS. 1-5), in each case provided alternately with untreated or surface-modified pigments, are lasered using an NdVO.sub.4 laser (1064 nm, 12 W) under the laser conditions shown in Table 5.

(24) The laser marking covers both the matter printed areas printed with untreated pigments and also the printed areas with a metallic lustre printed with surface-modified pigments, without inhomogeneities or differences in the laser marking thereby becoming evident. The laser marking thus produces a completely homogeneous, seamless and uniform connection over the printed areas having a different degree of reflection (FIG. 4).

(25) The choice of laser is not limited to the near IR region, but can also be extended to commercial lasers into the UV region (355 nm) or far IR region (10.6 m).

(26) TABLE-US-00005 TABLE 5 Laser parameters for various laser-induced effects using an NdVO.sub.4 laser (1064 nm, 12 W laser, actual laser power: 10.5 W) Energy Frequency Speed Focus Laser effect [%] [kHz] [mm/s] position [mm] Ablation without 100 16 170-2700 10 to +3 heating of the 90-100 10 400-800 +1 print substrate 100 10 500 1 Ablation with 100 2-64 170-2700 13 to +6 heating of the print 100 2-64 170-2700 13 to +5 substrate Dark coloration 100 16 2700 +12 without ablation 100 32 2000-2700 +14 100 2-64 170-2700 +5 to +14

(27) If a CO.sub.2 laser (10.6 m, 30 W laser, frequency 25 kHz) is used instead of an NdVO.sub.4 laser, ablation takes place, for example, at a laser power of 30-60% at a speed of 1000-3000 mm/s. A dark coloration of the substrate without ablation of the pigment layer can take place at a power of 20%, for example at a speed of 1000 mm/s, at a laser power of 30% at speeds of 1500-2000 mm/s or at a laser power of 70-80% at speeds of 2500-4000 mm/s.