Thin film interference pigments with nanoparticle coatings

Abstract

To provide: an article which includes a thin film interference pigment and a coating including a colored selectively absorbing nanoparticles, where the article can exhibit a change in hue, lightness and / or chroma compared to the thin film interference pigment alone; and methods of making the same.SOLUTION: An article comprises: a thin film interference pigment 12; and a coating 10 including colored selectively absorbing nanoparticles 14 on the thin film interference pigment.SELECTED DRAWING: Figure 22

Description

[Technical Field]

[0001] (Related Applications) This application claims the benefit of priority to U.S. Provisional Application No. 62 / 966,391, filed January 27, 2020, the entire disclosure of which is incorporated herein by reference. (Technical field)

[0002] The present disclosure generally relates to an article comprising a thin film interference pigment and a coating comprising colored selectively absorbing nanoparticles. Methods of making the article are also disclosed. [Background technology]

[0003] Fabry-Perot stacks exhibit color that is primarily dependent on the thickness of the dielectric layers in the structure, thus limiting the color variations that can be produced by the thickness of the dielectric layers.

[0004] One way to manipulate the color produced is to add colorants to the ink or paint vehicle containing the Fabry-Perot layer structure. However, blending colorants with the Fabry-Perot layer structure can be difficult to formulate to achieve the desired final color due to colorant variations in colorant concentration, colorant size, colorant distribution, etc. Additionally, blending colorants with the Fabry-Perot layer structure can be difficult to reproduce from batch to batch.

[0005] Another issue with blends is light scattering. In particular, when large amounts of colorant particles are dispersed in inks or paints, the scattering effects can significantly increase, leading to mutual interactions. Additionally, the colorant-absorbing pigments typically used in blends have large particle sizes, and these large particles can scatter light independently, further increasing light scattering. [Brief explanation of the drawings]

[0006] Features of the present disclosure are illustrated by, but not limited to, the following figures, in which like numerals refer to like elements: [Figure 1] FIG. 10 shows the reflectance of a gold preflake alone, a green spot, and a highly saturated green color. [Figure 2] This is a graph showing the hue of the sample in Figure 1 as a* and b*. [Figure 3] 1 shows low and high angle reflectance plots of thin film interference pigments and the characteristic absorbance of various selectively absorbing nanoparticles. [Figure 4] 4 is a reflectance plot of the thin film interference pigment of FIG. 3 at various angles from low to high angles. [Figure 5] FIG. 1 shows a thin film interference pigment with green to purple color travel and the characteristic absorbance of various selectively absorbing nanoparticles. [Figure 6] FIG. 1 shows thin film interference pigments with magenta to green color travel and the properties of various selectively absorbing nanoparticles. [Figure 7] FIG. 1 shows the reflectance of the red-to-gold color-shifting pigment alone, with three layers of cyan pigment (Exp 3C), and with four layers of cyan pigment (Exp 4C) under diffuse lighting. [Figure 8] FIG. 8 is a graph showing the hue of the sample in FIG. 7 under diffuse lighting using a* and b* graphs. [Figure 9] FIG. 8 is an L*a* graph showing the brightness of the sample in FIG. 7 under diffuse lighting. [Figure 10] 8 shows the color travel from red to gold or magenta to green (Exp 3C and Exp 4C) of the samples of FIG. 7 under direct illumination. [Figure 11] FIG. 8 is a diagram showing the color travel of lightness of the sample in FIG. 7 under direct lighting using an L*a* graph. [Figure 12] FIG. 1 shows the reflectance under diffuse lighting for blue-to-red color-shifting pigment alone, with two multilayers of yellow pigment (Exp 2Y), and with three multilayers of yellow pigment (Exp 3Y). [Figure 13]The hue of the sample in Figure 12 under diffuse lighting is shown in the a* and b* graphs. [Figure 14] FIG. 13 is an L*a* graph showing the brightness of the sample in FIG. 12 under diffuse lighting. [Figure 15] FIG. 13 shows the color travel from blue to red or green to orange (Exp 2Y, Exp 3Y) of the sample of FIG. 12 under direct illumination. [Figure 16] FIG. 13 is a diagram showing the color travel of lightness of the sample in FIG. 12 under direct lighting using an L*a* graph. [Figure 17] FIG. 1 shows the reflectance under diffuse lighting of a blue-to-red color-shifting pigment alone and with a blend containing cyan and magenta nanoparticles. [Figure 18] 18 is a graph showing the hue of the sample in FIG. 17 under diffuse lighting as a* and b*. [Figure 19] FIG. 18 is a diagram showing the lightness of the sample in FIG. 17 under diffuse lighting using an L*a* graph. [Figure 20] FIG. 18 shows the color travel of the sample of FIG. 17 under direct lighting. [Figure 21] FIG. 18 is a diagram showing the color travel of the lightness of the sample in FIG. 17 under direct lighting using an L*a* graph. [Figure 22] FIG. 1 is a cross-sectional view of an article showing reflected and transmitted color with discrete layers of nanoparticles. [Figure 23] FIG. 1 is a cross-sectional view of an article showing reflected and transmitted color in a coating of blended nanoparticles. Summary of the Invention

[0007] In one aspect, an article is disclosed that includes a thin film interference pigment and a coating on the thin film interference pigment that includes colored selectively absorbing nanoparticles.

[0008] In another aspect, a method of making an article is disclosed that includes providing a thin film interference pigment and coating the thin film interference pigment with colored selectively absorbing nanoparticles.

[0009] In one aspect, an article is disclosed that includes a thin film interference foil and a coating that includes colored selectively absorbing nanoparticles on the thin film interference pigment.

[0010] Additional features and advantages of various embodiments will be set forth in part in the description that follows, and in part will be obvious from the description, or may be learned by practice of various embodiments. The objectives and other advantages of the various embodiments will be realized and attained by means of the elements and combinations particularly pointed out in the description herein. DETAILED DESCRIPTION OF THE INVENTION

[0011] For simplicity and illustrative purposes, the present disclosure will be described primarily by reference to examples thereof. In the following description, numerous specific details are set forth to provide a thorough understanding of the present disclosure. However, it will be readily apparent that the present disclosure may be practiced without being limited to these specific details. In other instances, some methods and structures have not been described in detail so as not to unnecessarily obscure the present disclosure.

[0012] Additionally, the elements shown in the accompanying figures may include additional components, and some of the components depicted in those figures may be deleted and / or modified without departing from the scope of the present disclosure. Additionally, the elements shown in the figures may not be drawn to scale, and therefore, elements may have a different size and / or configuration than that shown in the figures.

[0013] It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are intended to provide a description of various embodiments of the present teachings. Disclosed herein in its wide variety of embodiments are articles, and methods of making and using the articles.

[0014] This disclosure describes articles that include a pigment 12, such as a thin film interference pigment, and a coating 10 that includes colored selectively absorbing nanoparticles 14, as shown in Figures 22 and 23. The coating 10 can manipulate the reflectance of the pigment 12 to enhance chromaticity and / or create colors (at both normal and oblique angles) not possible with the pigment 12 alone. Methods of manufacturing the disclosed articles can be cost-effective and provide high throughput of pigments.

[0015] In one embodiment, pigment 12 may include a core material selected from reflective opaque materials, translucent materials, and transparent materials, depending on the desired optical properties of the resulting pigment.

[0016] Pigment 12 can be a metal, nonmetal, or metal alloy. In one example, the material of pigment 12 can include any material with reflective properties in the desired spectral range. For example, any material with a reflectance in the desired spectral range ranging from 5% to 100%. An example of a reflective material can be aluminum, which has good reflective properties, is inexpensive, and is easy to form or deposit in thin layers. Non-limiting examples of reflective, opaque materials for use in pigment 12 include aluminum, copper, silver, gold, platinum, palladium, nickel, cobalt, niobium, chromium, tin, and iron, and combinations or alloys of these or other metals can also be used as pigments. In one embodiment, the material of pigment 12 can be a white or light-colored metal. In other examples, pigment 12 can include, but is not limited to, transition metals and lanthanide metals and combinations thereof, as well as metal carbides, metal oxides, metal nitrides, metal sulfides, and combinations thereof, or mixtures of metals and one or more of these materials. In one embodiment, pigment 12 can include a transparent or translucent material selected from glass, silica, titania, alumina, natural mica, synthetic mica, and bismuth oxychloride, hi another embodiment, pigment 12 can include a metalloid material selected from silicon, germanium, and molybdenum.

[0017] In another embodiment, pigment 12, such as a thin film interference pigment, can be any special effect pigment, such as a pigment including a reflector layer, a dielectric layer, and an absorber layer, and optionally a magnetic layer. Non-limiting examples of commercially available pigments include SPECTRAFLAIR®, CHROMAFLAIR®, Optical Variable Pigment (OVP), SecureShift, and Optical Variable Magnetic Pigment (OVMP), available from Viavi Solutions, Inc. (San Jose, Calif.).

[0018] A pigment 12, such as a thin-film interference pigment, can be coated with colored selectively absorbing nanoparticles 14. The nanoparticles 14 can selectively absorb any undesirable high- or low-angle colors from the reflectance spectrum of the pigment 12, such as a thin-film interference pigment. The undesirable colors can be located along the color travel path of the thin-film interference pigment 12 and can be located between different desired colors. In addition, the nanoparticles 14 can modify the desired color of the article at different viewing angles. Finally, the nanoparticles 14 can change the color shift of the pigment 12, such as a thin-film interference pigment, so that the color shift of the article is from low wavelength to high wavelength.

[0019] The selectively absorbing nanoparticles 14 may be colored and / or function as color filters. The selectively absorbing nanoparticles 14 may be nanoparticles selected from pigments, dyes, metal nanoparticles, metal oxides, metal carbides, metal sulfides, metal nitrides, and combinations thereof. Non-limiting examples of selectively absorbing nanoparticles 14 include titanium dioxide, zinc oxide, silicon dioxide, aluminum oxide, iron (II, III) oxide, zirconium dioxide, indium tin oxide, CeO2, zinc nitride, gold, silver, carbon black, iron oxide, mixed metal oxides, zinc sulfide, iron sulfide, copper sulfide, perylene, perinone, quinacridone, quinacridonequinone, anthrapyrimidine, anthraquinone, anthanthrone, benzimidazolone, disazo condensates, azo, quinolone, xanthene, azomethine, quinophthalone, indanthrone, phthalocyanine, triallyl carbonium, dioxazine, aminoanthraquinone, isoindoline, diketopyrrolopyrrole, thioindigo, thiazineindigo, isoindoline, isoindolinone, pyranthrone, isoviolanthrone, myosimethane, triallylmethane, and mixtures thereof. In one embodiment, the selectively absorbing nanoparticles 14 can be electrically charged.

[0020] In particular, the coating 10 can include selectively absorbing nanoparticles 14 in a suitable matrix. The coating 10 can include a plurality of colored selectively absorbing nanoparticles 14. In one embodiment, the coating 10 can also include non-colored selectively absorbing nanoparticles. In one embodiment, the coating 10 can also include non-colored organic polymer nanoparticles. In one embodiment, the coating 10 can include a plurality of selectively absorbing nanoparticles 14, all of which are the same color.

[0021] The coating 10 may be multi-layered, including two or more layers, each layer having colored selectively absorbing nanoparticles 14. For example, a layer may include cyan pigment nanoparticles 14, or a layer may include yellow pigment nanoparticles 14. The multi-layers may include two or more layers of selectively absorbing nanoparticles 14 of a first color and two or more layers of selectively absorbing nanoparticles 14 of a second color, where the first color is different from the second color. For example, a first layer may include cyan pigment nanoparticles 14 and a second layer may include yellow pigment nanoparticles 14.

[0022] The coating 10 may include two or more layers of colored, selectively absorbing nanoparticles 14, such as a first layer having a first proportion of colored, selectively absorbing nanoparticles 14 and a second layer having a second proportion of colored, selectively absorbing nanoparticles 14. For example, the first layer may include 30% by weight cyan pigment nanoparticles and the second layer may include 40% by weight cyan pigment nanoparticles 14.

[0023] In another embodiment, the coating 10 can include multiple selectively absorbing nanoparticles of different colors. In one embodiment, the coating 10 can be a layer including a blend of two or more differently colored selectively absorbing nanoparticles 14. The blend can include equal proportions of the two or more differently colored selectively absorbing nanoparticles 14. As an example, the blend can include a 50 / 50 split of cyan pigment nanoparticles 14 and yellow pigment nanoparticles 14. In another embodiment, the blend can include different proportions of the two or more differently colored selectively absorbing nanoparticles 14. For example, the blend can be an 80 / 20 split of cyan pigment nanoparticles 14 and yellow pigment nanoparticles 14. Any ratio of the two or more differently colored selectively absorbing nanoparticles 14 can be used in the coating 10.

[0024] Coating 10 may be multiple layers, with each layer containing a blend of two or more different colored selectively absorbing nanoparticles 14. For example, coating 10 may include a first layer having a blend of cyan / yellow pigment nanoparticles 14 and a second layer having a blend of magenta / yellow pigment nanoparticles 14.

[0025] The selectively absorbing nanoparticles 14 present in the coating 10 can be the same or different in terms of the nanoparticle 14 material, the average particle size of the nanoparticles 14, the concentration (volume percent) of the nanoparticles 14 in the coating 10, etc. In one embodiment, the coating 10 includes multiple selectively absorbing nanoparticles 14 that are different from one another. One skilled in the art can adjust the above-mentioned variables to achieve an article with a desired resulting color, including a desired brightness and saturation. For example, one skilled in the art can select a high concentration of weakly colored nanoparticles 14 with a large average particle size in the coating 10 to achieve a resulting color in the article with high saturation. Additionally and / or alternatively, one skilled in the art can select a moderate concentration of highly colored nanoparticles 14 with a small average particle size in the coating 10 and still achieve a resulting color in the article with high saturation.

[0026] The selectively absorbing nanoparticles 14 can have an average particle size in the range of less than about 300 nm, such as about 2 nm to about 100 nm, such as about 4 nm to about 95 nm, or even about 6 nm to about 90 nm. The average particle size can affect the color saturation of the resulting article. For example, a larger average particle size can increase the intensity and / or saturation of the resulting color of the article because the article achieves color saturation more quickly, i.e., with less material.

[0027] The concentration of the selectively absorbing nanoparticles 14 can also affect the color intensity and / or saturation of the resulting article. The selectively absorbing nanoparticles 14 can be present in the coating 10 in an amount greater than about 40% by volume, such as greater than about 65% by volume, and as a further example, greater than about 70% by volume. For example, a coating 10 having more than about 70% by volume of selectively absorbing nanoparticles 14 will have a higher color saturation compared to a coating 10 having about 65% by volume of selectively absorbing nanoparticles 14. As a further example, the color intensity of the article is increased with a high concentration of selectively absorbing nanoparticles 14 in the coating 10.

[0028] The coating 10 of selectively absorbing nanoparticles 14 can be a single layer or multiple layers. In one embodiment, the disclosed article can include a thin film interference pigment 12 having a coating 10 with multiple layers of selectively absorbing nanoparticles 14, each layer in the multiple layers containing a plurality of different selectively absorbing nanoparticles 14. The use of multiple layers can also increase the color saturation of the article.

[0029] The coating 10 of selectively absorbing nanoparticles 14 can be applied continuously or discontinuously to the surface of the pigment 12, such as a thin film interference pigment. In one embodiment, the coating 10 is continuous on the surface of the pigment 12. In another embodiment, the coating 10 is discontinuous on the surface, reducing the effect on light scattering. The coating 10 of selectively absorbing nanoparticles 14 can be present on more than about 90% of the surface of the pigment 12, such as more than about 95% of the pigment 12, or even, for example, on the entire surface of the pigment 12 (100% continuous / sealed). In one embodiment, the coating 10 of selectively absorbing nanoparticles 14 can be discontinuous, such as in the form of spots, lines, etc. A fully sealed coating can increase the color intensity of the article.

[0030] In one embodiment, coating 10 may, but should not, adversely affect the hiding properties of thin film interference pigment 12 .

[0031] The selectively absorbing nanoparticles 14 may have other properties other than or in addition to absorbing ultraviolet (UV) light. In one embodiment, the selectively absorbing nanoparticles 14 may have a property selected from fluorescent, phosphorescent, thermochromic, photochromic, and infrared (IR) fluorescent (anti-Stokes).

[0032] Exposure to ultraviolet light can degrade the nanoparticles. In one embodiment, coating 10 can include other particles that can protect the nanoparticles, such as particles that absorb ultraviolet light and / or reduce the photocatalytic activity inherent in some nanoparticles. Coating 10 can include other particles such as titanium dioxide, zinc oxide, silicon dioxide, Al2O3, CeO2, etc.

[0033] Nanoparticles can also exhibit metallic resonant plasmonic effects, which can be enhanced by local magnetic fields, resulting in nanoparticles exhibiting different spectral responses depending on the light source (e.g., polarized or unpolarized).

[0034] In one embodiment, instead of a thin film interference pigment, the article can include a thin film interference foil and a coating 10 of selectively absorbing nanoparticles 14 on the thin film interference foil. This article can be used as a thread for security applications. The coating 10 of selectively absorbing nanoparticles 14 can be as described herein. The article can include a substrate (PET) and have the following structure: PET / absorber / dielectric / reflector / coating 10 of selectively absorbing nanoparticles 14. In another embodiment, the article can have the following structure: PET / reflector / dielectric / absorber / coating of selectively absorbing nanoparticles.

[0035] The disclosed methods for manufacturing the articles can be carried out using techniques such as layer-by-layer technology. In one embodiment, the method can include providing a post-treated thin film interference pigment. In another embodiment, the method can include fabricating the thin film interference pigments 12 and 10 using selectively absorbing nanoparticles.

[0036] A method of making an article disclosed herein may include providing a pigment 12, such as a thin film interference pigment, and coating 10 the thin film interference pigment with colored selectively absorbing nanoparticles 14. The coating step may include providing a first layer of charged nanoparticles 14 on the pigment 12; rinsing; providing a second layer of charged nanoparticles 14 on the first layer of charged nanoparticles 14, where the second charged nanoparticle 14 material is oppositely charged from the first charged nanoparticle material 14; and rinsing, whereby a coating 10 of selectively absorbing nanoparticles 14 is formed on the surface of the pigment 12. The steps of providing a first layer of charged nanoparticles 14 and providing a second layer of charged nanoparticles 14 may be repeated such that the coating 10 of selectively absorbing nanoparticles 14 is a stacked coating 10.

[0037] The coating step may also include providing a layer of a first charged polymer on the pigment; rinsing; providing a layer of first charged nanoparticles on the first charged polymer layer, where the first charged nanoparticle material is oppositely charged from the first charged polymer material; and rinsing, whereby a selectively absorbing nanoparticle coating 10 is formed. The steps of providing a layer of a first charged polymer and providing a layer of first charged nanoparticles may be repeated such that the selectively absorbing nanoparticle coating 10 is a laminated coating 10.

[0038] The coating step may also include a final step of providing a charged polymer to the final coating 10 containing the charge-selectively absorbing nanoparticles in layers to provide a specific surface functionalization of the pigment.

[0039] The coating 10 of selectively absorbing nanoparticles 14 can completely encapsulate a pigment, such as the thin film interference pigment 12. The coating 10 is continuous on all surfaces of the pigment. Alternatively, the coating 10 of selectively absorbing nanoparticles 14 can encapsulate only a portion of a pigment, such as the thin film interference pigment 12. The coating 10 can be continuous but encapsulate only a portion of the pigment. The coating 10 can be discontinuous and encapsulate only a portion of the pigment.

[0040] Alternatively, the layered coating 10 can be created by alternating layers of selectively absorbing nanoparticles with layers of charged polymers (polyelectrolytes) or other molecules with interacting binding sites. That is, the layered configuration comprises one or more materials with ionic groups of opposite charge. A simple layered configuration can be ABAB(AB)n, where n is an integer greater than 1. Note that even though they are labeled as different materials A and B, the two materials can be the same material with oppositely charged surfaces. The layered coating 10 can also use more materials. The layered coating 10 can include any material, depending only on the choice of charge for each material.

[0041] The step of providing a layer of first or second charged nanoparticles can use any technique, such as filtration, sedimentation, or centrifugation. These processes can involve sequential application of the first charged nanoparticles (A), a rinsing step, and resuspension / application of the second charged nanoparticles (B), followed by settling of the nanoparticles or filtration or centrifugation (faster processes). Other processes can include continuous filtration using systems such as filter reactors, trickle-bed reactors, upflow reactors, and membrane reactors. Alternatively, the pigment can be forced (i.e., sprayed) into an area containing an atomized solution of the first charged nanoparticles (A), a rinsing medium, and the second charged nanoparticles (B). Alternative deposition techniques include wet coating methods, including dip coating, spin coating, flow coating, spray coating, roll coating, gravure coating, and similar methods.

[0042] The rinsing step can be carried out using any solvent, such as a polar solvent. Non-limiting examples of solvents include water; acetates such as ethyl acetate, propyl acetate, and butyl acetate; acetone; ketones such as dimethyl ketone (DMK), methyl ethyl ketone (MEK), sec-butyl methyl ketone (SBMK), tert-butyl methyl ketone (TBMK), cyclopentanone, and anisole; glycols and glycol derivatives such as propylene glycol methyl ether and propylene glycol methyl ether acetate; alcohols such as isopropyl alcohol and diacetone alcohol; esters such as malonates; heterocyclic solvents such as n-methylpyrrolidone; hydrocarbons such as toluene and xylene; coalescing solvents such as glycol ethers; and mixtures thereof.

[0043] The method may further include providing a layer on the surface of the pigment prior to providing the nanoparticle coating 10. The layer may be positioned between the thin-film interference pigment and the coating 10 to protect the thin-film interference pigment or provide a receiving surface for the coating 10. In one aspect of the present invention, distributing a receiving layer on the surface of the pigment may allow for controlled distribution of the selectively absorbing nanoparticle-containing coating 10. In particular, this layer may inhibit oxidation of the pigment when exposed to the selectively absorbing nanoparticle coating 10. This layer may include, for example, a sol-gel layer of a material such as silica, titania, alumina, zirconia, ceria, or a combination thereof, or a polymer layer. In one aspect, a method for manufacturing an article may include providing a pigment; providing a first layer of charged nanoparticles on the pigment; rinsing; providing a layer of charged polymer (polyelectrolyte) or other molecules with interactive binding sites; rinsing; providing a second layer of charged nanoparticles on the layer of charged polymer (polyelectrolyte) or other molecules with interactive binding sites; and rinsing.

[0044] The method can further include providing a second protective layer on top of the nanoparticle coating 10. The second protective layer can include a layer of charged polymers (polyelectrolytes) or other organic molecules with interactive binding sites, or a sol-gel layer. In one embodiment, a second protective layer of charged polymers (polyelectrolytes) or other organic molecules with interactive binding sites can provide the pigment with a functionalized outer surface whose properties, such as hydrophilicity, hydrophobicity, oleophilicity, permeability, hardness, and rigidity, can be tuned.

[0045] In an additional aspect, the method may further include encapsulating the selectively absorbing nanoparticles coated on the pigment with a protective layer.

[0046] The method can include preparing a thin film interference pigment on a substrate having a release layer, which can be compatible with liquid coating processes and vacuum deposition.

[0047] The method may include several post-processing steps such as stripping the article from the release layer / substrate, polishing, etc. [Example]

[0048] (Example)

[0049] Example 1 Gold thin film interference pigment 12 (gold preflake) was coated to varying degrees to produce different levels of intensity depending on the saturation / intensity of the coated selectively absorbing nanoparticles 14. The data are shown in Figures 1 and 2. The thin film interference pigment 12 was based on a Cr / ZnS / Al / ZnS / Cr structure. The gold thin film interference pigment 12 was fully encapsulated with a continuous coating 10 of selectively absorbing nanoparticles 14, i.e., a cyan pigment with a high concentration (high green saturation). The same gold thin film interference pigment 12 was fully encapsulated with a continuous coating 10 of selectively absorbing nanoparticles 14, i.e., the same cyan pigment, but with a lower concentration of selectively absorbing nanoparticles 14 in the coating, e.g., 65% by volume (not shown). The gold thin film interference pigment 12 was partially encapsulated with a discontinuous coating 10 of selectively absorbing nanoparticles 14, i.e., the same cyan pigment, but with a larger average particle size (not shown) compared to the other two samples with continuous coatings. The high green saturation article and the green spot article each exhibit green in reflection, but with different hues and varying intensities and saturations. The high green saturation has a higher intensity / color saturation than the green spot. The green spot has a less saturated color, i.e., a lighter color, due to the total reflected light coming from areas of the thin film interference pigment 12 that are not filtered by the coating 10. The high concentration of selectively absorbing nanoparticles 14 in the coating 10 increases the color intensity of the article. Additionally, adding layers to the coating 10 increases the color intensity of the article.

[0050] Optical characterization of the three samples was performed using paint drawdowns on Leneta cards and analyzed under diffuse illumination using a DC650 photospectrometer. Table 1 shows the lightness (L*), a*, b*, chroma (c*), and hue of the articles. As can be seen, the lightness (L*) decreases and the hue increases with increasing coating 10 of selectively absorbing nanoparticles 14.

[0051] [Table 1]

[0052] Figure 1 shows the reflectance of the gold thin film interference pigment 12 (gold preflake) alone, the green spot, and the green high saturation. Figure 2 illustrates the hue of the samples in Figure 1 using an a*, b* graph. Looking at Figures 1 and 2, it can be seen that the color develops as the concentration and / or encapsulation of the coating 10 of selectively absorbing nanoparticles 14 (cyan pigment) increases. As reported in Table 1 and shown in Figure 2, the green high saturation article was green with a high hue value of 162.88, followed by the green spot article, which visually appeared as a yellow-green with a hue value of 111.48, and the gold preflake was gold with a hue value of 89.8 (without the coating 10 of selectively absorbing nanoparticles 14 (e.g., cyan pigment)).

[0053] Example 2 The normal and high-angle (60°) color of commercially available pigments (cyan, magenta, yellow, and green) coated with selectively absorbing nanoparticles 14 was used to determine the expected dominant spectral color. However, depending on the variables discussed above, such as intensity, absorption, and nanoparticle concentration, the color shift trajectory of the coated thin-film interference pigment 12 may vary. Furthermore, the optical properties of the selectively absorbing nanoparticles 14 may have small spectral changes that alter the observed visual color. For example, many cyan pigments exhibit a band tail that produces a yellow component in the visible range. Therefore, the spectral absorption of the selectively absorbing nanoparticles 14 can be used to better predict the final color travel of an article (thin-film interference pigment 12 coated with selectively absorbing nanoparticles 14).

[0054] New color travel as a function of illumination and viewing angle can be predicted based on a plot of reflectance versus wavelength for the thin-film interference pigment 12 and the wavelength and intensity absorbed by the coating 10 of selectively absorbing nanoparticles 14. Figure 3 shows the reflectance plots for the thin-film interference pigment 12 at low (10°) and high (55°) angles, demonstrating color travel from green to blue. Figure 3 also shows the absorption of several other selectively absorbing nanoparticles 14 in cyan, yellow, magenta, red, blue, and black. This figure shows that a coating 10 of selectively absorbing nanoparticles 14, such as a yellow pigment that is a blue light absorber, can partially or completely eliminate the blue reflection at high angles, shifting the article to a very dark or black appearance. Figure 4 shows the reflectance curve for the thin-film interference pigment 12 when viewed from normal to high angles. The coating 10 of selectively absorbing nanoparticles 14 (i.e., yellow pigment) not only interferes with reflectance at angles greater than 45°, but can also affect color at other angles. It was also determined that the design of the thin film interference pigment 12 could be modified to change the color peak position at different angles, changing the angle at which some reflection peaks are blocked.

[0055] Example 3 Color travel from special effect pigments based on thin film interference varies from high wavelengths to low wavelengths as the viewing angle changes from normal (low) to high. Table 2 below lists four selectively absorbing nanoparticles 14 and the wavelength colors absorbed by each. Table 2 also lists two thin film interference pigments 12 and their wavelength colors at normal (low) and high angles. Table 2 also lists the predicted reflected color of an article including the thin film interference pigment 12 and a coating 10 with selectively absorbing nanoparticles 14.

[0056] [Table 2]

[0057] Figure 5 shows the color travel of a thin-film interference pigment 12, shifting from green to purple. Because there were two reflectance peaks at high angles, it was possible to select a suitable single selectively absorbing nanoparticle 14, such as a yellow pigment, or a suitable blend of nanoparticles to force the color travel in the opposite direction, such as from green to red. Figure 5 also shows the absorption of several other selectively absorbing nanoparticles 14: cyan, yellow, magenta, red, blue, and black.

[0058] Figure 6 shows the color travel of a thin film interference pigment 12 that is color-shifted from magenta to green, essentially the opposite of the pigment illustrated in Figure 5. Thus, there are typically two reflectance peaks. To force color travel in the opposite direction, such as from magenta (blue) to red, it was possible to select appropriate selectively absorbing nanoparticles 14, such as a cyan pigment, or an appropriate blend of nanoparticles 14.

[0059] The following examples illustrate that the article can exhibit changes in hue, lightness, and saturation compared to thin film interference pigment 12. For example, the article can exhibit a decrease in lightness and an increase in saturation, or an increase in lightness and a decrease in saturation, compared to thin film interference pigment 12. Furthermore, the color travel of the article can be different from the color travel of thin film interference pigment 12.

[0060] Example 4 Red-to-gold thin film interference pigment 12 (CFWR) was coated with three layers (EXP 3C) of cyan pigment (selectively absorbing nanoparticles) and four layers (EXP 4C) of cyan pigment (selectively absorbing nanoparticles). Each coating completely covered the thin film interference pigment 12. The reflectance of the thin film interference pigment and the two articles is shown in Figure 7. Figures 8 and 9 show the hue and lightness of the thin film interference pigment 12 and the two articles, respectively. Table 3 below shows the lightness (L*), a*, b*, chroma (c*), and hue.

[0061] [Table 3]

[0062] The data in Figures 7-9 and Table 3 show that the red color of thin film interference pigment 12 became more magenta with the addition of coating 10 containing colored selectively absorbing nanoparticles (cyan pigment). The change in hue, as shown in Figure 8, was accompanied by a decrease in lightness, as shown in Figure 9.

[0063] Figures 10 and 11 show the color travel of the thin film interference pigment 12 and the two articles under direct lighting. Figure 10 shows that the red-to-gold color travel of the thin film interference pigment 12 shifted to a magenta to green hue with three multi-layer coatings of cyan pigment 10 and four multi-layer coatings of cyan pigment 10. As shown in Figure 11, the addition of the coatings reduced the lightness compared to the thin film interference pigment alone. Furthermore, the effect of increasing the number of coatings (layers) was greater at near-normal angles (15 degrees) compared to high-angle angles (65 degrees).

[0064] Example 5 A blue-to-red thin film interference pigment 12 (CFWR) was coated with two multilayers of yellow pigment (selectively absorbing nanoparticles) (EXP 2Y) and three multilayers of yellow pigment (selectively absorbing nanoparticles) (EXP 3Y). Each coating completely covered the thin film interference pigment 12. The reflectance of the thin film interference pigment 12 and the two articles is shown in Figure 12. Figures 13 and 14 show the hue and lightness for the thin film interference pigment 12 and the two articles, respectively. Table 4 below shows the lightness (L*), a*, b*, chroma (c*), and hue.

[0065] [Table 4]

[0066] According to the data in Figures 12-14 and Table 4, the blue coloration of thin film interference pigment 12 became a neutral blue when a coating containing two layers of yellow pigment was added, and became more greenish when a coating containing three layers of yellow pigment 10 was added. The decrease in hue, as shown in Figure 13, was accompanied by a decrease in lightness, as shown in Figure 14.

[0067] Figures 15 and 16 show the color travel of the thin film interference pigment 12 and the two articles under direct lighting. Figure 15 shows that the color travel of the thin film interference pigment 12 from blue to red became more neutral with two multi-layer coatings 10 of yellow pigment, and changed to a darker blue / green to orange with three multi-layer coatings 10 of yellow pigment. The color at high angles (65 degrees) did not change significantly with the number of multi-layer coatings 10. As shown in Figure 16, the addition of the colored selectively absorbing nanoparticle coatings 10 decreased the brightness. The color near normal (15 degrees) was more affected by the addition of the coatings than the color at high angles (65 degrees).

[0068] Example 6 A blue-to-red thin film interference pigment 12 (CFWR) was coated with three layers of a blend of cyan and magenta selectively absorbing nanoparticles. Each layer of the blend contained 66% by weight cyan pigment and 33% by weight magenta pigment. The reflectance of the thin film interference pigment 12 and the blend is shown in Figure 17. Figures 18 and 19 show the hue and lightness, respectively, for an article having a blend of thin film interference pigment 12 and coating 10. Table 5 below shows the lightness (L*), a*, b*, chroma (c*), and hue.

[0069] [Table 5]

[0070] The data in Figures 17-19 and Table 5 show that the inherent blue / magenta color development of thin film interference pigment 12 was not significantly affected by coating 10. In particular, there was minimal change in hue, as shown in Figure 18 and Table 5. There was also a slight decrease in lightness, as shown in Figure 19, and an increase in saturation, as shown in Table 5.

[0071] Figures 20 and 21 show the color travel of the thin film interference pigment 12 and the article under direct lighting. Figure 20 shows that the blue-to-red color travel of the thin film interference pigment 12 was not significantly affected by the coating 10 at near-normal (15-degree) angles. The color at high angles (65 degrees) showed a larger change at high angles (65 degrees). As shown in Figure 21, the article with the blend coating 10 was darker than the thin film interference pigment 12 alone. Figures 20 and 15 clearly demonstrate how the choice of thin film interference pigment 12, such as selectively absorbing nanoparticles 14 and color-shifting preflakes, can affect the color of the article at normal or high angles. The article exhibits different colors at near-normal and high angles compared to the thin film interference pigment 12.

[0072] Example 7 FIG. 22 shows an article including a coating 10 containing a thin film interference pigment 12 and colored selectively absorbing nanoparticles 14. The coating 10 is multilayered, including two or more layers, each containing colored selectively absorbing nanoparticles 14. Layer 22 contains a cyan pigment as the colored selectively absorbing nanoparticles 14. Layer 24 contains a yellow pigment as the colored selectively absorbing nanoparticles 14. An incident light beam 16 is received by the article, resulting in reflected light 18 and transmitted light 20. Reflected light 18 is the same color as the last applied layer of coating 10, which in this example was cyan. Transmitted light 20 is magenta. The order of two or more layers changes the color in reflection while maintaining the color in transmission.

[0073] Example 8 Figure 23 shows an article including a thin film interference pigment 12 and a coating 10 including a blend of two or more different colored selectively absorbing nanoparticles 14. In this example, the blend has cyan and yellow pigments as the colored selectively absorbing nanoparticles 14. An incident light beam 16 was received by the article, resulting in reflected light 18 and transmitted light 20. The reflected light 18 was a blend of the cyan and yellow nanoparticles; in this case, the reflected light 18 was green, and the transmitted light 20 was magenta.

[0074] In comparison, standard translucent special effect pigments (e.g., all dielectric pigments, dichroic pigments, pearlescent pigments) transmit a color that is complementary to the color they reflect. For example, a standard translucent special effect pigment reflects red and transmits green. The articles disclosed herein can be designed to exhibit different reflected / transmitted colors other than complementary colors.

[0075] From the foregoing description, those skilled in the art will appreciate that the present teachings can be embodied in a variety of forms. Accordingly, while these teachings have been described with reference to specific embodiments and examples thereof, the true scope of the present teachings should not be so limited. Various changes and modifications can be made without departing from the scope of the teachings herein.

[0076] The disclosure of this scope may be broadly construed. This disclosure is intended to disclose equivalents, means, systems, and methods for implementing the coatings, devices, functions, and mechanical actions disclosed herein. For each disclosed coating, device, article, method, means, mechanical element, or mechanism, this disclosure is also intended to teach equivalents, means, systems, and methods for implementing the many aspects, mechanisms, and apparatuses encompassed by that disclosure and disclosed herein. Furthermore, this disclosure relates to coatings and their many aspects, features, and elements. Such coatings may be dynamic in their use and operation, and this disclosure is intended to encompass equivalents, means, systems, and methods of use of the apparatus of manufacture and / or optical devices, and their many aspects, that are consistent with the description and spirit of the operation and functions disclosed herein. The claims of this application may likewise be broadly construed. The description of many embodiments of the invention herein is merely exemplary in nature, and thus, variations that do not depart from the gist of the invention are intended to be within its scope. Such variations are not considered to depart from the spirit and scope of the invention. [Explanation of symbols]

[0077] 10 Coating 12 Pigments 14. Selectively Absorbing Nanoparticles 16 Incident light 18 Reflected light 20 Transmitted light 22 layers 24 layers

Claims

1. An article, a thin film interference pigment; a coating comprising multiple layers of colored selectively absorbing nanoparticles on said thin film interference pigment; Equipped with the article is an interference pigment; i) each layer of the plurality of layers comprises a blend of selectively absorbing nanoparticles of two or more different colors; or ii) the plurality of layers comprises two or more layers of selectively absorbing nanoparticles of a first color and two or more layers of selectively absorbing nanoparticles of a second color, wherein the first color is different from the second color; The selective absorption nanoparticles include dyes, metal carbides, metal sulfides, metal nitrides, zinc oxide, aluminum oxide, zirconium dioxide, indium tin oxide, CeO ２ , zinc nitride, carbon black, iron oxide, mixed metal oxides, perylene, perinone, quinacridone, quinacridonequinone, anthrapyrimidine, anthraquinone, anthanthrone, benzimidazolone, azo compounds, quinolones, xanthenes, quinophthalones, indanthrones, phthalocyanines, triallylcarbonium, dioxazines, aminoanthraquinones, isoindolines, diketopyrrolopyrroles, thioindigo, thiazineindigo, isoindolines, isoindolinones, pyranthrone, isoviolanthrone, miyoshimethane, and triallylmethane; The article, wherein the selectively absorbing nanoparticles have an average particle size of less than 300 nm.

2. The article of claim 1 , wherein the blend comprises two or more different colored selectively absorbing nanoparticles in equal weight percentages.

3. The article of claim 1 , wherein the blend comprises two or more different colored selectively absorbing nanoparticles in different weight percentages.

4. 10. The article of claim 1, wherein the sequence of the two or more layers changes color in reflection and maintains color in transmission.

5. 10. The article of claim 1, wherein the plurality of layers includes a first layer having a first proportion of colored, selectively absorbing nanoparticles and a second layer having a second proportion of colored, selectively absorbing nanoparticles.

6. The article of claim 1 , wherein the coating is continuous.

7. The article of claim 1 , wherein the selectively absorbing nanoparticle coating is discontinuous.

8. 10. The article of claim 1, wherein the selectively absorbing nanoparticles are nanoparticles selected from pigments, dyes, metal oxides, metal carbides, metal sulfides, and combinations thereof.

9. 1. A method of manufacturing an article, comprising: providing a thin film interference pigment; coating the thin film interference pigment with colored selectively absorbing nanoparticles; Including, the coating is multi-layered, comprising two or more layers of colored selectively absorbing nanoparticles; the article is an interference pigment; i) each layer of the plurality of layers comprises a blend of selectively absorbing nanoparticles of two or more different colors; or ii) the plurality of layers comprises two or more layers of selectively absorbing nanoparticles of a first color and two or more layers of selectively absorbing nanoparticles of a second color, wherein the first color is different from the second color; The selective absorption nanoparticles include dyes, metal carbides, metal sulfides, metal nitrides, zinc oxide, aluminum oxide, zirconium dioxide, indium tin oxide, CeO ２ , zinc nitride, carbon black, iron oxide, mixed metal oxides, perylene, perinone, quinacridone, quinacridonequinone, anthrapyrimidine, anthraquinone, anthanthrone, benzimidazolone, azo compounds, quinolones, xanthenes, quinophthalones, indanthrones, phthalocyanines, triallylcarbonium, dioxazines, aminoanthraquinones, isoindolines, diketopyrrolopyrroles, thioindigo, thiazineindigo, isoindolines, isoindolinones, pyranthrone, isoviolanthrone, miyoshimethane, and triallylmethane; The method of making an article, wherein the selectively absorbing nanoparticles have an average particle size of less than 300 nm.

10. The method of claim 9 , wherein the coating completely encapsulates the thin film interference pigment.

11. The method of claim 9 , wherein the coating encapsulates a portion of the thin film interference pigment.

12. 10. The method of claim 9, wherein the color travel of the article is different from the color travel of the thin film interference pigment.

13. The method of claim 9 , wherein each layer of the plurality of layers comprises a blend of two or more different colored selectively absorbing nanoparticles.

14. 14. The method of claim 13, wherein the article exhibits a change in hue, a decrease in lightness, and an increase in chroma compared to the thin film interference pigment, or wherein the article exhibits a change in hue, an increase in lightness, and a decrease in chroma compared to the thin film interference pigment.

15. a thin film interference foil; a coating comprising colored selectively absorbing nanoparticles on said thin film interference foil; the coating is multi-layered, including two or more layers of colored selectively absorbing nanoparticles; i) each layer of the plurality of layers comprises a blend of selectively absorbing nanoparticles of two or more different colors; or ii) the plurality of layers comprises two or more layers of selectively absorbing nanoparticles of a first color and two or more layers of selectively absorbing nanoparticles of a second color, wherein the first color is different from the second color; The selective absorption nanoparticles include dyes, metal carbides, metal sulfides, metal nitrides, zinc oxide, aluminum oxide, zirconium dioxide, indium tin oxide, CeO ２ , zinc nitride, carbon black, iron oxide, mixed metal oxides, perylene, perinone, quinacridone, quinacridonequinone, anthrapyrimidine, anthraquinone, anthanthrone, benzimidazolone, azo compounds, quinolones, xanthenes, quinophthalones, indanthrones, phthalocyanines, triallylcarbonium, dioxazines, aminoanthraquinones, isoindolines, diketopyrrolopyrroles, thioindigo, thiazineindigo, isoindolines, isoindolinones, pyranthrone, isoviolanthrone, miyoshimethane, and triallylmethane; The article, wherein the selectively absorbing nanoparticles have an average particle size of less than 300 nm.

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