LAYER SEQUENCE WITH COLOUR FLOP EFFECT INCLUDING PLATELET-SHAPED EFFECT PIGMENTS

Abstract

The present invention relates to a system, which comprises: b) at least one first colour layer containing a dye and/or pigment, c) on the at least one first colour layer an effect layer containing at least one platelet-shaped effect pigment, wherein the at least one platelet- shaped effect pigment is composed of particles having an average length of 2 to 500 m, an average width of 2 to 500 m and an average thickness of at most 1 gm, and d) on the effect layer at least one second colour layer containing a dye and/or pigment, wherein each of the at least one first colour layer and of the at least one second colour layer contains a dye and/or pigment being no platelet-shaped effect pigment, wherein the at least one dye and/or at least one pigment included in the at least one first colour layer is different from the at least one dye and/or at least one pigment included in the at least one second colour layer, and wherein, at least if the at least one first colour layer has a sum of reflectance and scattering of less than 40%, the system further comprises: a) below the at least one first colour layer a lower layer containing a pigment and having a sum of reflectance and scattering of at least 40%.

Claims

1.-13. (canceled)

14. A system comprising: b) at least one first colour layer (18) containing a dye (26) and/or pigment, c) on the at least one first colour layer (18) an effect layer (20) containing at least one platelet-shaped effect pigment (28), wherein the at least one platelet-shaped effect pigment (28) is composed of particles (46) having an average length (48) of 2 to 500 m, an average width (50) of 2 to 500 m and an average thickness of at most 1 m, and d) on the effect layer (20) at least one second colour layer (22) containing a dye (30) and/or pigment, wherein each of the at least one first colour layer (18) and of the at least one second colour layer (22) contains a dye (26, 30) and/or pigment being no platelet-shaped effect pigment, wherein the at least one dye (26) and/or at least one pigment included in the at least one first colour layer (18) is different from the at least one dye (30) and/or at least one pigment included in the at least one second colour layer (22), and wherein, at least if the at least one first colour layer (18) has a sum of reflectance and scattering of less than 40%, the system further comprises: a) below the at least one first colour layer (18) a lower layer (16) containing a pigment (24) and having a sum of reflectance and scattering of at least 40%, wherein the system does not contain any interference pigment, wherein an interference pigment is defined to be a pigment which produces an interference of light waves.

15. The system in accordance with claim 14, wherein the at least one platelet-shaped effect pigment (28) is a platelet-shaped metal effect pigment.

16. The system in accordance with claim 14, wherein the at least one platelet-shaped effect pigment (28) is composed of particles (46) having an average thickness of 0.01 to at 1 m.

17. The system in accordance with claim 14, wherein the at least one platelet-shaped effect pigment (28) is composed of particles (46) having a first aspect ratio of the average particle length (48) divided by the average particle width (50) of 1 to 20.

18. The system in accordance with claim 14, wherein the at least one platelet-shaped efect pigment (28) is composed of particles (46) having a second aspect ratio of the average particle length (48) divided by the average particle thickness of 1 to 75,000.

19. The system in accordance with claim 14, wherein the average particle area ratio of the effect layer (20) is 5 to 75.

20. The system in accordance with claim 14, wherein the effect layer (20) has a thickness of 0.1 to 50 m.

21. The system in accordance with claim 14, wherein the weight ratio of pigment to binder in the dry effect layer (20) is 0.02:1 to 2:1.

22. The system in accordance with claim 14, wherein the effect layer (20) has a sum of reflectance and scattering of 20 to 100%.

23. The system in accordance with claim 14, wherein the lower layer (16) is present and: i) is a film and contains 0.1 to 10% by weight of white pigment (24) based on the total weight of the lower layer (16), wherein the film has a thickness of 1 to 100 m, or ii) is a paper or cardboard and contains 0.1 to 50% by weight of white pigment (24) based on the total weight of the lower layer (16) or iii) is an ink and contains 10 to 90% by weight of white pigment (24) based on the total weight of the dry lower layer (16), wherein the ink has a thickness of 0.5 to 100 m or iv) is a coating or lacquer and contains 10 to 90% by weight of white pigment (24) based on the total weight of the dry lower layer (16), wherein the coating or lacquer has a thickness of 0.5 to 1,000 m.

24. The system in accordance with claim 14, wherein the lower layer (16) is present and the dye (26, 30) and/or pigment included in each of the at least one first colour layer (18) and of the at least one second colour layer (22) is different from the pigment (24) contained in the lower layer (16).

25. The system in accordance with claim 14, wherein any of the at least one first colour layer (18) and of the at least one second colour layer (22) contains 0.001 to 5% by weight of at least one dye (26, 30) and/or 0.1 to 50% by weight of at least one pigment being no white pigment and no metallic pigment, based on the total dry weight of the first colour layer (18) and/or second colour layer (22).

26. The system in accordance with claim 14, wherein the delta a/b is at least 15, wherein the delta a/b is determined according to the equation delta a/b=((a[15]a[110]).sup.2+(b[15]b[110]).sup.2).sup.1/2, wherein a[15] is the a-value measured at an observation value of 15, a[110] is the a-value measured at an observation value of 110, b[15] is the b-value measured at an observation value of 15 and b[110] is the b-value measured at an observation value of 110, wherein the measurement is performed by irradiating in a dark environment a standardized light type onto the system at an angle of incident of 45 with respect to the horizontal direction, wherein the angle of reflection of 135 with respect to the horizontal direction is defined as an observation angle of 0.

26. A system comprising: b) at least one first colour layer (18) containing a dye (26) and/or pigment, c) on the at least one first colour layer (18) an effect layer (20) containing at least one effect pigment (28) and d) on the effect layer (20) at least one second colour layer (22) containing a dye (30) and/or pigment, wherein each of the at least one first colour layer (18) and of the at least one second colour layer (22) contains a dye (26, 30) and/or pigment being no effect pigment, wherein the at least one dye (26) and/or at least one pigment included in the at least one first colour layer (18) is different from the at least one dye (30) and/or at least one pigment included in the at least one second colour layer (22), and wherein, at least if the at least one first colour layer (18) has a sum of reflectance and scattering of less than 40%, the system further comprises: a) below the at least one first colour layer (18) a lower layer (16) containing a pigment (24) and having a sum of reflectance and scattering of at least 40%, wherein: i) the delta a/b of the system is at least 15, wherein the delta a/b is determined according to the equation delta a/b=((a[15]a[110]).sup.2+(b[15]b[110]).sup.2).sup.1/2, wherein a[15] is the a-value measured at an observation value of 15, a[110] is the a-value measured at an observation value of 110, b[15] is the b-value measured at an observation value of 15 and b[110] is the b-value measured at an observation value of 110, wherein the measurement is performed by irradiating in a dark environment a standardized light type onto the system at an angle of incident of 45 with respect to the horizontal direction, wherein the angle of reflection of 135 with respect to the horizontal direction is defined as an observation angle of 0, and/or ii) the delta L of the system is at least 10, wherein the delta L is determined according to the equation delta L=|L[15]L[110]|, wherein L[15] is the L-value measured at an observation value of 15 and L[110] is the L-value measured at an observation value of 110 , wherein the measurement is performed by irradiating in a dark environment a standardized light type onto the system at an angle of incident of 45 with respect to the horizontal direction, wherein the angle of reflection of 135 with respect to the horizontal direction is defined as an observation angle of 0, and/or iii) the delta h of the system is at least 15, wherein the delta h is determined according to the equation delta h=|h[15]h[110]|, wherein h[15] is the h-value measured at an observation value of 15 and h[110] is the h-value measured at an observation value of 110, wherein the measurement is performed by irradiating in a dark environment a standardized light type onto the system at an angle of incident of 45 with respect to the horizontal direction, wherein the angle of reflection of 135 with respect to the horizontal direction is defined as an observation angle of 0, and wherein the system does not contain any interference pigment, wherein an interference pigment is defined to be a pigment which produces an interference of light waves.

27. The system in accordance with claim 26, wherein the delta a/b of the system is at least 15.

28. The system in accordance with claim 15, wherein the at least one platelet-shaped effect pigment is composed of particles having an average thickness of 0.01 to at 1 m.

29. The system in accordance with claim 15, wherein the at least one platelet-shaped effect pigment is composed of particles having a first aspect ratio of the average particle length divided by the average particle width of 1 to 20.

30. The system in accordance with claim 28, wherein the at least one platelet-shaped effect pigment is composed of particles having a first aspect ratio of the average particle length divided by the average particle width of 1 to 20.

31. The system in accordance with claim 16, wherein the at least one platelet-shaped effect pigment is composed of particles having a first aspect ratio of the average particle length divided by the average particle width of 1 to 20.

32. The system in accordance with claim 15, wherein the at least one platelet-shaped effect pigment is composed of particles having a second aspect ratio of the average particle length divided by the average particle thickness of 1 to 75,000.

33. The system in accordance with claim 16, wherein the at least one platelet-shaped effect pigment is composed of particles having a second aspect ratio of the average particle length divided by the average particle thickness of 1 to 75,000.

Description

[0110] Subsequently, the present invention is described by means of illustrating, but not limiting figures, wherein:

[0111] FIG. 1 shows an object comprising a substrate, which is coated with an ink system in accordance with one embodiment of the present invention.

[0112] FIG. 2 shows schematically a method for measuring the angle dependent colour measurement of a system in accordance with one embodiment of the present invention.

[0113] FIG. 3 shows the results of angle dependent colour measurements of four different systems in accordance with one embodiment of the present invention.

[0114] FIG. 4a, b show sample holders, which are suitable for fixing longitudinal sections or cross-sectional sections of a system in accordance with the present invention or of a layer thereof for SEM analysis for determining the particle length, particle width and particle thickness.

[0115] FIG. 4c shows an exemplary schematic pigment particle showing the particle length and particle width.

[0116] FIG. 5a,b show the principle of the determination of the average particle area ratio of a layer of the system in accordance with the present invention.

[0117] FIG. 6 shows the principle of the determination of the reflectance and scattering of a layer of the system in accordance with the present invention.

[0118] FIG. 1 shows a system 10, which comprises a substrate 12, which is coated with an ink sequence 14 in accordance with one embodiment of the present invention. The ink sequence 14 comprises from the bottom up a lower layer 16, a first colour layer 18, an effect layer 20 and a second colour layer 22. The lower layer 16 contains white pigment 24 preferably consisting of titanium oxide having an average diameter of 0.1 to 50 m in a concentration of about 30 to 90% by weight of white pigment based on the total weight of the dried lower layer 16. Moreover, the first colour layer 18 contains about 0.001 to 5% by weight of dye 26 and/or about 0.1 to 50% of pigment, based on the total weight of the dry first colour layer 18, whereas the effect layer 20 includes 10 to 70% by weight of metallic effect pigment, e.g, platelet-shaped aluminium effect particles, 28 consisting of aluminium having an average particle length of about 10 m, an average particle width of about 5 m, an average thickness of about 0.5 m and thus a first aspect ratio of 2 and a second aspect ratio of 20, based on the total weight of the dried effect layer 20 and the second colour layer 22 contains about 0.001 to 5% by weight of dye 30 and/or 0.1 to 50% of pigment based on the total weight of the dried second colour layer 22.

[0119] FIG. 2 shows schematically a method for measuring the angle dependent colour appearance of a system in accordance with one embodiment of the present invention. In a dark environment, a visible light beam 40 with an adjusted intensity and wavelength range is irradiated onto a system 10 as described for instance with regard to FIG. 1 at an angle of 45 with respect to the horizontal direction. Since the angle of incidence with regard to the horizontal direction is the same as the angle of reflection 42 of the irradiated light beam, the angle of reflection 42 is 135 with respect to the horizontal direction. This angle of reflection 42 is defined for the measurement of the angle dependent colour appearance of the system in accordance with the present invention as an observation angle of 0. In order to measure the angle dependent colour appearance of the system 10, the sum of reflectance and scattering is measured at different observation angles 44, 44, 44, for instance as shown in FIG. 2at observation angles of 15, 15, 25, 45, 75 and 110. Of course, it is also possible to measure the colour appearance at more than six different observation angles or at less than six different observation angles, such as at five different observation angles, such as at observation angles of 15, 25, 45, 75 and 110. For these measurements, for example a Byk mac i instrument from Byk Garnder, Geretsried, Germany can be used, with D50 light incidence and a six angle measurement at the observation angles describes above. It is most suitable to measure rectangular samples with a minimum width of 2 cm and a minimum length of 5 cm. It is especially preferred that at least 10 samples are measured, even more preferred is the measurement of 100 or even 600 samples.

[0120] FIG. 3 shows the results of angle dependent colour measurements of four different systems in accordance with one embodiment of the present invention. The angle dependent colour measurements of the four different systems have been performed as described above with regard to FIG. 2 at observation angles of 15, 15, 25, 45, 75 and 110. At each observation angle, the a-value as well as the b-value of each system have been determined. The respective values are plotted in FIG. 3 for any of the four systems, wherein the largest triangle of each graph represents the value measured at an observation angle of 15. The further markers in each graph starting from the largest triangle represent the respective values determined at observation angles of 15, 25, 45, 75 and 110. The horizontal axis of FIG. 3 shows the measured a-values, whereas the vertical axis of FIG. 3 shows the measured b-values. As it can be seen from FIG. 3, the a-values and b-values of all four samples differ depending of the observation angle at which they have been determined. This shows, that all four systems showed a flip-flop effect.

[0121] FIGS. 4a and 4b show sample holders, which are suitable for fixing longitudinal sections or cross-sectional sections, respectively, of a system in accordance with the present invention or of a layer thereof for SEM analysis for determining the particle length, particle width and particle thickness. The sample holder shown in FIG. 4a is suitable for longitudinal sections of a layer or a system (for frontal view), whereas the sample holder shown in FIG. 4b is suitable for cross-sectional sections of a layer or a system. The sections are placed onto the respective sample holder area as shown by the blue arrow.

[0122] FIG. 4c shows an exemplary schematic pigment particle 46 showing the particle length 48 and particle width 50. The particle length 48 is the longest extension of the particle 46, whereas the particle width 50 is defined in this connection as the longest extension of the particle 46 in the direction being perpendicular to the particle length 48. The particle thickness is the shortest extension of the particle 46 in the direction being perpendicular to the two-dimensional plane being defined by the particle length 48 and the particle width 50, i.e. the extension of the particle perpendicular to the paper plane.

[0123] FIGS. 5a and 5b show the principle of the determination of the average particle area ratio of a layer of the system in accordance with the present invention by SEM from a longitudinal section of the concerned layer of the system being prepared as described above. The particles 46 are colored with the software tool

[0124] ParticleMetric as shown in FIG. 5a and then the sum of the area in the longitudinal section which is covered by particles 46 as shown in FIG. 5b is evaluated and divided by the total area of the longitudinal section analyzed by scanning electron microscopy so as to obtain the average particle area ratio in percent.

[0125] FIG. 6 shows the principle of the determination of the reflectance and scattering of a layer of the system in accordance with the present invention. A piece of the prepared layer, such as a longitudinal section thereof or the layer itself, having for instance an area of 10 cm.sup.2 is cut out of the system and placed in the measurement apparatus, which is preferably the Haze-Gloss instrument from Byk Garnder,

[0126] Geretsried, Germany. Norm light D65 shown by the reference number 52 is irradiated in defined angle of 20 from the vertical direction onto the surface of the layer 54 to be analyzed and the reflected (which corresponds to gloss 56, as described in DIN 67530) as well as the scattered light (which corresponds to haze 58) is detected by a sensor 60.

[0127] Subsequently, the present invention is described by means of illustrating, but not limiting examples.

EXAMPLE

[0128] Solvent-based: flexographic inks based on nitrocellulose and polyurethane (NC/PU) have been printed on 30 m thick foils of oriented polypropylene (OPP). The following inks from the hubergroup Deutschland. GmbH: 61GU336812 (Yellow; abbreviated subsequently as Y), 62GU336816 (Magenta; abbreviated subsequently as M), 63GU336821 (Cyan; abbreviated subsequently as C), 69GU336827 (Black; abbreviated subsequently as Bk), 77GU289376 (White; abbreviated subsequently as W) and 76GU318960 (Silver; abbreviated subsequently as S) were printed onto the foils at a print viscosity 20s in a DIN 4 cup. The inks have been diluted with ethanol/ethyl acetate 9:1. The pigment-binder ratio in the dry ink film was 0,9: 1 to 1.5:1 for the inks Y, M, C and Bk, 1:0.3 for W and 0.9:1 for S, wherein between 0.7 and 1.5 g/m.sup.2 of dry ink (for each ink) have been applied. The following ink sequences have been printed, from the bottom up:

TABLE-US-00001 System Layer 1 Layer 2 Layer 3 Layer 4 Layer 5 Layer 6 1 White Yellow Silver Magenta Cyan Black 2 White Yellow Silver Magenta Black 3 White Magenta Silver Yellow Cyan Black 4 White Magenta Silver Yellow Black 5 White Cyan Silver Yellow Magenta Black 6 White Cyan Silver Yellow White Black

[0129] The layers, which correspond to the respective print forms, were as follows:

TABLE-US-00002 Layer 1 Layer 2 Layer 3 Layer 4 Layer 5 Layer 6 Lines/cm 360 360 360 220 360 120 Ink volume 4.0 3.9 3.9 8.0 3.9 16.4 [cm.sup.3/m.sup.2]

[0130] The flip-flop effects for each system were measured with a Byk mac I instrument.

[0131] A five angle measurement for alb travel evaluation was carried out at observation angles of 15/15/25/45/75/110. In order to assess the degree of the flip-flop effect for each system, the a- and b-values of the L*a*b* colour space were measured at observation angles of 15 and of 110 and therefrom the ratio delta alb has been determined according to the following equation:

Delta a/b=((a[15]a[110]).sup.2+(b[15]b[110]).sup.2).sup.1/2

[0132] The higher the numeric value of delta at, the higher the flip-flop effect.

[0133] For seven different trials, the following results were obtained:

TABLE-US-00003 Colour/Ink Coverage of Layer No. Delta a/b 1 2 3 4 5 6 15/110 Trial 1 (Coverage) White 100 Yellow 100 Silver 90 Magenta 10 Cyan 30 Black 0 50.9 Trial 2 (Coverage) White 100 Magenta 100 Silver 100 Yellow 10 Cyan 50 Black 0 41.1 Trial 3 (Coverage) White 100 Cyan 90 Silver 80 Yellow 40 Magenta 20 Black 0 38.9 Trial 4 (Coverage) White 100 Cyan 90 Silver 100 Yellow 40 Magenta 0 Black 10 38.9 Trial 5 (Coverage) White 100 Yellow 70 Silver 90 Magenta 30 Cyan 20 Black 20 19.9 Trial 6 (Coverage) White 100 Magenta 70 Silver 90 Yellow 20 Cyan 10 Black 30 16.6 Trial 7 (Coverage) White 100 Cyan 70 Silver 100 Yellow 10 Magenta 10 Black 20 17.0

[0134] Thus, the highest colour flip-flop effects have been achieved for 90 to 100% ink coverage for the colour ink printed between the white and silver layers, for 80 to 100% ink coverage for the silver layer, for 0 to 10% coverage for the optional black layer and sum of ink coverage of 40 to 60% for all inks printed on the side above the silver, i.e. effect layer.

[0135] In an additional trial, the colours Y, M and C have been extended by 100% with extender 60GU319987, resulting in pigment binder ratios of 0.9:2 to 1.5:2. Also by using these colours, the flip-flop effect was observed.

EXAMPLE 2

[0136] In another trial, solvent-based inks based on NC/PU have been tested in gravure printing: Cyan 63GU514973, Magenta 62GU514969, Yellow 61GU515076, Black 69GU515074, White 67GU515182, Silver 66GU515184, and Extender 70GU504288 (hubergroup Deutschland GmbH).

[0137] Cyan and Magenta were extended by 120%. Yellow, Silver and white were printed without extender. The inks have again been diluted to 20s in a DIN 4 cup with ethanol/ethylacetate 9:1. The inks were applied on corona treated OPP film with a

[0138] Roto Hand Proofer (Pamarco). The following ink sequences have been investigated from bottom to up:

[0139] W-Y-S-M-C-Bk, W-S-Y-M-C, W-Y-S-M-Bk and W-S-Y-M-C-Bk.

[0140] W is the abbreviation for White, Y for Yellow, S for Silver, M for Magenta, C for Cyan and Bk for Black.

[0141] In this trial it was observed that inks with a higher pigmentation showed less visible flip-flop effect, indicating that transparency was not sufficient at the ink film thickness achieved with gravure printing with standard pigment content. Between 0.7 and 1.5 g/m.sup.2 of ink (for each ink) have been applied. The pigment binder ratio was 1.5:2 to 3:2 for Yellow, Cyan, Magenta and Silver, and 2:3 for White. Delta alb 15/110 values of up to 40 have been achieved when yellow was printed between white and silver, and the other inks above or before silver.

EXAMPLE 3

[0142] In a third trial the inks from example 2 have been applied using a K-printing-proofer 100 I/cm (RK Print Coat Instruments). The same inks and ink sequences have been applied as in example 2, resulting in an ink film of 0.13 to 0.8g/m.sup.2. It was observed that the inks had to be further extended by another 100% to observe an optimal flip-flop effect, resulting in a pigment binder ratio of 1:2 to 1:6 for Yellow, 1:8 to 1:10 for Cyan and Magenta, 1:1.5 for Silver and 1:0.7 for White. A delta alb 15/110 of 27 has been achieved with the ink sequence white, yellow, silver, cyan, and of 35 for the ink sequence white, yellow, silver, magenta.

[0143] In addition, the present invention refers to the following feature combinations or aspects, respectively. Each of the following aspects may be combined with the aforementioned embodiments.

EXAMPLE 4

[0144] Solvent-based flexographic inks based on NC/PU have been printed on 30 m thick foils of white oriented polypropylene (OPP). The following inks from the hubergroup Deutschland GmbH: 61GU336812 (Yellow; abbreviated subsequently as Y), 62GU336816 (Magenta; abbreviated subsequently as M), 63GU336821 (Cyan; abbreviated subsequently as C) and 76GU318960 (Silver; abbreviated subsequently as S) were printed onto the foils at a print viscosity 20s in a DIN 4 cup. The inks have been diluted with ethanol/ethyl acetate 9:1. The pigment-binder ratio in the dry ink film was 0.9: 1 to 1.5:1 for the inks Y, M and C and 0.9:1 for S, wherein between 0.7 and 1.5 g/m.sup.2 of dry ink (for each ink) have been applied. The following ink sequences have been printed, from the bottom up:

TABLE-US-00004 Layer 1 Layer 2 Layer 3 Layer 4 Layer 5 Layer 6 Layer 7 Yellow Magenta Cyan Silver Yellow Magenta Cyan Layer 1 Layer 2 Layer 3 Layer 4 Layer 5 Layer 6 Layer 7 Lines/cm 360 360 360 220 360 360 360 Ink volume [cm.sup.3/m.sup.2] 3.9 3.9 3.9 8.0 3.5 3.5 3.5

[0145] The flip-flop effects for each system were measured with a Byk mac I instrument. A five angle measurement for a/b travel evaluation was carried out at observation angles of +15/15/25/45/75/110. In order to assess the degree of the flip-flop effect for each system, the h-values of the HCL colour space were measured at observation angles of 15 and of 110.sup.0 and therefrom the ratio delta h has been determined according to the following equation:

h=|h[110]h[15]|,

[0146] which equals the absolute difference between these two h values.

[0147] For different ink sequences and ink coverages the following numbers were obtained:

TABLE-US-00005 Colours below Colours above silver = Layer b silver = Layer d Sum of Delta Y M C Silver Y M C layer d h-15P h15P h25P h45P h75P h110P h(15/110) 50 0 0 33 0 67 33 100 325.5 328 333 357 6.45 8.71 41 50 0 0 33 0 67 0 67 0.34 3.61 5.88 18.9 23.6 25.05 21 50 0 0 33 0 33 0 33 19.53 26.3 37 50.2 53.4 54.31 28 50 0 0 33 0 0 67 67 212.3 214 202 183 178 178.8 35 0 50 0 33 0 0 67 67 238.8 240 249 262 266 266.7 26 0 50 0 33 33 0 0 33 66.94 71.7 55.8 39.9 35.2 34.65 37 0 50 0 33 67 0 33 100 114.1 112 107 91.9 83.1 80.57 31 0 50 0 33 0 0 33 33 254.1 255 270 294 300 301 46 0 0 50 33 0 33 0 33 312.8 310 293 275 269 267.8 42 0 0 50 33 67 0 0 67 105 108 116 131 137 138.5 30 0 0 50 33 67 33 0 100 78.98 79.1 85.3 104 115 117 38 0 0 50 33 33 67 0 100 21.64 13.8 1.4 342 331 328.8 45 50 0 0 67 0 67 0 67 3.28 0.81 6.15 19.2 24 25.87 25 50 0 0 67 0 0 100 100 233.6 216 211 199 194 194.5 21 50 0 0 67 0 67 33 100 330.5 333 322 345 359 1.84 29 50 0 0 67 0 33 0 33 8.11 12.6 22.6 46.9 54.2 56.02 43 100 0 0 67 0 0 33 33 206.4 198 162 124 116 114.5 84 100 0 0 67 0 33 100 133 232.8 227 219 190 173 170.8 56 100 0 0 67 0 0 67 67 216.5 213 196 158 142 140.2 73 100 0 0 67 0 100 0 100 357.3 355 0.55 20 31.3 34.2 39 0 50 50 67 33 0 0 33 97.25 104 102 116 172 202 98 0 100 0 67 33 0 0 33 78.18 71.2 51.6 25.2 17.5 17.39 54 0 100 0 67 100 0 67 167 128.9 127 126 116 98.4 89.77 37 0 100 0 67 0 0 100 100 230 229 233 255 277 282.3 53 0 100 50 67 67 0 0 67 94.68 95.2 91.8 75.9 51.7 45.22 50 0 100 0 67 67 0 33 100 109.3 111 101 55.6 28.4 25.14 86 0 100 0 67 0 0 67 67 235.5 237 251 285 302 304.9 67 0 100 0 67 67 0 0 67 83.74 80.5 69.1 45.2 34.8 33.85 47 0 50 100 67 67 0 0 67 101.1 101 107 133 161 166.6 65 0 0 100 67 67 33 0 100 86.42 89.7 105 150 170 173.2 84 0 0 100 67 0 67 0 67 326.6 330 315 291 278 275.3 54 0 0 100 100 67 0 0 67 99.46 101 111 141 161 164.2 63 0 0 100 100 100 67 0 167 64.15 66 64 72.5 95 104.8 39 0 100 0 100 0 0 33 33 254.2 248 254 306 328 332.4 85 0 50 0 100 0 0 100 100 232.9 228 235 245 250 250.5 22 0 0 100 100 33 0 0 33 110.6 114 137 182 194 196.8 83 0 0 50 100 33 67 0 100 16.19 21.9 12.4 2.18 350 347.4 35 0 100 0 100 100 0 0 100 89.93 87.5 82.8 68.4 57.8 56.19 31 0 100 0 100 67 0 100 167 187.3 186 188 197 212 217.6 32 0 100 0 100 33 0 100 133 210.8 210 212 228 250 256.9 47 0 100 100 100 100 0 0 100 95.19 94.7 96.7 104 117 119 24 0 0 100 100 33 100 0 133 5.29 29.4 2.39 350 332 325.5 64 0 100 0 100 100 0 0 100 89.03 87.4 83 68.3 56.9 54.77 33 0 50 0 100 33 0 67 100 200.5 199 202 211 219 222.2 23 0 0 100 100 100 0 0 100 97.45 97.1 103 123 141 144.1 47 0 0 50 100 100 33 0 133 82.86 83 85.6 94.6 102 102.9 20 0 0 50 100 0 67 0 67 338.6 336 330 318 310 307.9 28 0 50 0 100 67 0 0 67 89.8 86.8 81.4 70.2 64.7 63.51 23 0 100 0 100 0 0 100 100 227.8 227 233 254 277 282.3 55 0 0 100 100 0 33 0 33 319.3 315 295 267 257 255.7 59 0 0 50 100 100 0 0 100 96.58 96.5 101 114 122 122.7 26 0 0 100 100 0 100 0 100 341.6 341 337 326 315 312.5 29 Remark: The h values are polar coordinates of between 0 and 360.

EXAMPLE 5

[0148] In this experiment automotive coatings have been applied to sheet metal substrates. The following recipes based on standard products from the Nexa Autocolor Aquabase colour mixing system have been used:

TABLE-US-00006 Silver, silver, Silver, Compound Red Blue Green fine medium coarse Clear P990-8999 50 50 40 40 40 Red P993-8941 30 Blue P990-8957 2 Transparent Green 2 P991-8952 Extra fine 2 Aluminium P998-8985 Medium bright 2 Aluminium P-998-8988 Extra coarse 2 Aluminium P998-8989 Wasser 2 3 3 8 8 8 Sum 32 55 55 50 50 50 Pigment binder ratio 1:2 1:13 1:13 1:5 1:5 1:5 D.sub.90/D.sub.10-Particel 5-25 10-40 25-75 size [m] D10 and D90 are the intercepts for 10% and 90% of the cumulative mass of the particles.

[0149] The lacquers have been applied using a Sata Jet 5000, pressure 1.6 bar for application of first colour Red, 1.9 bar for allocation of Silver types, Blue and Green.

[0150] The following layer sequences have been applied:

TABLE-US-00007 First layer Second Layer Third Layer Red Silver, fine Blue Red Silver, medium Blue Red Silver, coarse Blue Red Silver, fine Green Red Silver, medium Green Red Silver, coarse Green

[0151] In a last step a clear coat, solvent based product from Nexa, was applied on the substrates.

[0152] The coatings had the following thicknesses:

[0153] Red: was applied twice, final red layer thickness was about 30 m

[0154] Silver: was applied once/twice, final silver layer thickness was about 15/30 m

[0155] Blue/Green: was applied once/twice, final blue/green layer thickness was about 20/40 m

[0156] Clearcoat: was applied twice, final clear coat layer thickness was 90-100 m. As clearcoat, 2K HS Plus Clearcoat P190-6570 (2 parts) plus hardener P210-8645 (1 part) both from Nexa Autocolor, from PPG Industries, Ohio was used.

[0157] The coated substrates were measured with a Byk mac I instrument as described above, some exemplary measurement results are listed in the following table:

TABLE-US-00008 L* h 1st colour Silver 2nd colour 15 15 25 45 75 110 L 15 15 25 45 75 110 h Red, twice fine, once green, once 67 61 48 32 26 23 38 109 88 51 33 35 35 53 Red, twice fine, twice green, once 80 74 58 38 28 24 50 136 127 94 39 32 32 95 Red, twice medium, once green, twice 74 65 41 26 23 21 43 130 110 45 33 36 36 74 Red, twice medium, twice green, twice 96 85 56 30 23 21 64 146 143 108 32 31 31 111 Red, twice coarse, twice green, twice 53 46 29 23 22 20 26 102 71 36 36 37 36 35 Red, twice coarse, twice green, once 57 50 32 24 24 22 28 89 61 34 37 38 38 23 Red, twice fine, once blue, once 56 52 38 22 16 13 38 219 226 266 356 16 18 152 Red, twice fine, twice blue, once 73 68 50 28 18 14 54 216 220 238 326 6 10 150 Red, twice medium, once blue, once 52 47 33 18 13 11 36 215 221 256 347 7 6 145 Red, twice medium, twice blue, once 48 44 31 16 11 9 35 215 220 245 327 354 353 133 Red, twice coarse, twice blue, once 37 33 20 13 11 9 24 222 235 321 0 9 5 130 Red, twice coarse, twice blue, twice 37 32 19 12 10 8 24 221 235 313 355 4 359 124 L = Delta L = |L[15] L[110]| h = Delta h = |h[15] h[110]|

[0158] Colour flop was observed for all investigated combinations. The use of small and medium size aluminium pigment particle showed a more intensive flip-flop effect.

[0159] When bigger aluminium particles are used the colour flop is pretty good visible on the particles themselves, but it cannot be properly measured and evaluated.

[0160] Further aspects of the present invention are described below. [0161] Aspect 1. A system comprising: [0162] a) a lower layer (16) containing white pigment (24), [0163] b) on the lower layer (16) at least one first colour layer (18) containing a dye (24) and/or pigment being different from the white pigment (24) contained in the lower layer (16) and being no metallic pigment, [0164] c) on the at least one first colour layer (18) a metallic layer (20) containing at least one metallic pigment (28) and [0165] d) on the metallic layer (20) at least one second colour layer (22) containing a dye (30) and/or pigment being different from the white pigment (24) contained in the lower layer (16) and being no metal effect pigment. [0166] Aspect 2. The system in accordance with aspect 1, wherein at least at an angle of 0 to 45 with respect to the horizontal direction the colour shade of the visible light (34) being reflected and scattered by the metallic layer (20) is different to the colour shade of the visible light (38) being reflected by the lower layer (16). [0167] Aspect 3. The system in accordance with aspect 1 or 2, wherein the white pigment (24) included in the lower layer (16) is selected from the group consisting of titanium dioxide, barium sulfate, zinc oxide, zinc sulfide, lead carbonate, calcium carbonate, aluminium oxide, aluminium silicate and arbitrary combinations of two or more of the aforementioned substances. [0168] Aspect 4. The system in accordance with any of the preceding aspects, wherein the lower layer (16): [0169] i) is a foil/film and contains 0.1 to 10% by weight, preferably 0.25 to 4% by weight and more preferably 0.75 to 1.5% by weight of white pigment (24) based on the total weight of the lower layer (16), wherein the foil/film has preferably a thickness of 1 to 100 m, more preferably of 2 to 50 m and most preferably of 10 to 30 m, or [0170] ii) is a paper or cardboard and contains 0.1 to 50% by weight, preferably 1 to 10% by weight and more preferably 3 to 7% by weight of white pigment (24) based on the total weight of the lower layer (16) or [0171] iii) is an ink and contains 10 to 90% by weight and preferably 30 to 90% by weight of white pigment (24) based on the total weight of the lower layer (16), wherein the ink has preferably a thickness of 1 to 10,000 m. [0172] Aspect 5. The system in accordance with any of the preceding aspects, wherein the white pigment (24) included in the lower layer (16) is titanium oxide and preferably rutile and present in the form of particles having an average d.sub.50 particle size of 0.1 to 50 m, preferably of 0.1 to 10 m and more preferably of 0.2 to 0.5 m. [0173] Aspect 6. The system in accordance with any of the preceding aspects, wherein the metallic layer (20) is an ink having a ratio of pigment to binder in the metallic layer (20) is 0,3:1 to 2:1, preferably 0,7:1 to 2:1 and more preferably 0,7:1 to 1,8:1. [0174] Aspect 7. The system in accordance with any of the preceding aspects, wherein the metallic pigment (28) included in the metallic layer (20) is present in the form of platelets having an average d.sub.50 size of 2 m to 3000 m. [0175] Aspect 8. The system in accordance with any of the preceding aspects, wherein the metallic layer (20) has a thickness of 0.1 to 50 m, more preferably of 0.5 to 20 m and most preferably of 1 to 10 m. [0176] Aspect 9. The system in accordance with any of the preceding aspects, wherein the ink coverage of the metallic layer (20) on the at least one first colour layer (18) is 40 to 100%, more preferably 70 to 100%, even more preferably 80 to 100% and most preferably 90 to 100%, wherein the ink coverage is the percentage of the area of the upperst of the first colour layer(s) (18), which is covered by the metallic layer (20). [0177] Aspect 10. The system in accordance with any of the preceding aspects, wherein the dry laydown of the metallic layer (20) is 0.2 to 2 gsm, more preferably 0.3 to 1.5 gam and most preferably 0.4 to 1.2 gsm. [0178] Aspect 11. The system in accordance with any of the preceding aspects, wherein the weight ratio of pigment to binder in the metallic layer (20) is 0.3:1 to 2:1, more preferably 0.7:1 to 2:1 and most preferably 0.7:1 to 1.8:1. [0179] Aspect 12. The system in accordance with any of the preceding aspects, wherein any of the first colour layer (18) and of the at least one second colour layer (22) contains 0.001 to 5% by weight of at least one dye (26, 30) and/or 0.1 to 50% by weight of at least one pigment being no white pigment and no metallic pigment, based on the total dry weight of the first colour layer (18) and/or second colour layer (22). [0180] Aspect 13. The system in accordance with any of the preceding aspects, wherein the at least one dye (26) and/or at least one pigment included in the first colour layer (18) is different from the at least one dye (30) and/or at least one pigment included in the at least one second colour layer (22). [0181] Aspect 14. The system in accordance with any of the preceding aspects, which does not contain any interference pigment. [0182] Aspect 15. The system in accordance with any of the preceding aspects, wherein the delta a/b is at least 15, more preferably at least 30 and most preferably at least 38, wherein the delta a/b is determined according to the equation delta a/b=((a[15]a[110]).sup.2(b[15]+b[110]).sup.2).sup.1/2, wherein a[15] is the a-value measured at an observation value of 15, a[110] is the a-value measured at an observation value of 110, b[15] is the b-value measured at an observation value of 15 and b[110] is the b-value measured at an observation value of 110, wherein the measurement is performed by irradiating in a dark environment a standardized light type onto the system at an angle of incident of 45 with respect to the horizontal direction, wherein the angle of reflection of 135 with respect to the horizontal direction is defined as an observation angle of 0.

LIST OF REFERENCES

[0183] 10 System/Coated object [0184] 12 Substrate [0185] 14 Ink Sequence [0186] 16 Lower layer [0187] 18 First colour layer [0188] 20 Effect layer [0189] 22Second colour layer [0190] 24 White pigment [0191] 26 First dye [0192] 28 Platelet-shaped effect pigment [0193] 30 Second dye [0194] 40 Irradiated light beam [0195] 42 Angle of reflection of the irradiated light beam [0196] 44, 44, 44 Angle of measurement of reflectance/scattering/colour shade [0197] 46 Pigment particle [0198] 48 Particle length [0199] 50 Particle width [0200] 52 Norm light [0201] 54 Surface of layer [0202] 56 Gloss [0203] 58 Haze [0204] 60 Sensor [0205] Angle of incidence of norm light