Composition comprising double-cavity color shifting pigment

Abstract

The invention discloses a composition comprising a double-cavity color shifting pigment and a single-cavity color shifting pigment. Methods of making the compositions are also disclosed.

Description

[0001] This case is a divisional application of the patent application with application number 202080081013.X filed by the present applicant on October 6, 2020 and entitled “A composition comprising dual-cavity color-shifting pigments”. The entire contents of the parent case are incorporated into this divisional by reference. Technical Field

[0002] The present disclosure generally relates to a composition including a dual-cavity color shifting material and a single-cavity color shifting material. Methods of making and using the composition are also disclosed. Technical Background

[0003] Interference pigments typically include a reflective layer, a dielectric layer and an absorber layer. The dielectric layer forms an optical cavity that filters out light of a specific wavelength by destructive interference. In some cases, it is beneficial to add a second cavity on top of the first cavity, thereby forming a double cavity. This is achieved by adding a dielectric layer and an absorber layer. However, the production of double cavity pigments is not simple and double cavity pigments are relatively thick, heavy and expensive. In particular, controlling the exact color (hue, brightness, chroma) in roller coating relies on an extremely high level of layer control that needs to be performed in a closed loop.

[0004] One way to achieve a target color is to intentionally coat to slightly different specifications and blend with sub-batches. Blending has a negative impact on color performance. In addition, blending with dual cavity pigments is not simple because many variables affect color performance in different ways. Therefore, it would be simpler to formulate a composition based on the optimal color performance (provided by the dual cavity pigment) and accept the color difference or otherwise adjust for the color difference.

[0005] Another way to achieve the target color is to use dual cavity pigments but make the internal absorber layer thinner, which will allow some additional energy in the blue wavelengths, i.e., this allows the process path to be moved to a lower hue angle. However, it has been found that a thin internal absorber layer can lead to significant problems with color stability. In particular, this leads to significant color shifts with slight oxidation of the internal absorber layer, resulting in highly undesirable drastic changes in the final color.

[0006] Single cavity color shifting pigments can be easier to manufacture than dual cavity color shifting pigments, for example, it is easier to manufacture single cavity color shifting pigments with a specific hue, lightness and chroma. For this reason, batch-to-batch color variation is smaller. However, single cavity color shifting materials have inferior color performance.

[0007] There is a need for compositions having at least some of the following properties: cost effectiveness, high chroma, and high color stability. Summary of the invention

[0008] In one aspect, the present invention discloses a composition comprising a dual cavity color shifting pigment; and a single cavity color shifting pigment.

[0009] In another aspect, the present invention discloses a method of forming a composition comprising mixing a dual cavity color shifting pigment and a single cavity color shifting pigment.

[0010] Additional features and advantages of various embodiments will be described in part in the following description, and will be apparent in part from the description, or can be understood through the practice of various embodiments. The purposes and other advantages of various embodiments will be realized and obtained through the elements and combinations particularly pointed out in the description herein. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Several aspects and embodiments of the present invention may be more fully understood from the detailed description and accompanying drawings, in which:

[0012] Figure 1 is an L*a*b* diagram showing the process path of a single-cavity color-shifting pigment in three dimensions (3D);

[0013] Figure 2 yes Figure 1 Two-dimensional (2D) version of

[0014] Figure 3 is an L*a*b* diagram showing the process path of dual-chamber color-shifting pigments in three dimensions (3D);

[0015] Figure 4 yes Figure 3 Two-dimensional (2D) version of

[0016] Figure 5 is the L*a*b* diagram, showing the Figure 1 Single-chamber color-shifting pigments and Figure 3 Overlapping process paths for each of the dual-chamber color-shifting pigments;

[0017] Figure 6 yes Figure 5 2D version of

[0018] Figure 7 yes Figure 6 , showing a blending path from red to gold for a composition according to one aspect of the present invention (2D);

[0019] Figure 8 yes Figure 7 3D version of

[0020] Fig. 9 is a L*a*b* plot (2D) showing overlapping process paths for each of the single cavity color shifting pigment, the dual cavity color shifting pigment, and the blending path from violet to bronze for a composition according to another aspect of the present invention.

[0021] In the present specification and drawings, the same reference numerals represent the same elements. DETAILED DESCRIPTION

[0022] It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide explanation of various embodiments of the present teachings.

[0023]

[0013] In a broad and varied embodiment of the present application, disclosed herein is a composition comprising a dual cavity color shifting pigment; and a single cavity color shifting pigment.

[0024] "Single cavity" is understood to mean a core, a dielectric layer and optionally an absorber layer on a single side of an article such as a pigment or flake. For example, a single cavity may comprise a core and a dielectric layer on each side of the core. "Core" is understood to mean a layer selected from the group consisting of a reflective layer, a magnetic layer or a combination of a reflective layer and a magnetic layer, for example the following structure: reflective layer / magnetic layer / reflective layer. "Dual cavity" is understood to mean a core, a first dielectric layer, an absorber layer, a second dielectric layer and optionally a second absorber layer on a single side of an article such as a pigment or flake. For example, a dual cavity may comprise the following structure and variations thereof: dielectric / absorber / dielectric / core / dielectric.

[0025] The composition can achieve improved color performance that cannot be achieved by using either the dual cavity color shifting pigment or the single cavity color shifting pigment alone. In particular, the dual cavity color shifting pigment and the single cavity color shifting pigment exhibit color shifting with angle, although the color shift is not the same. Although non-optically variable pigments or other colorants can be used with single cavity color shifting pigments or dual cavity color shifting pigments to improve color performance, non-optically variable pigments or other colorants do not exhibit color shifting and are not within the scope of the present invention.

[0026] The composition can produce surface colors that cannot be achieved using a single-chamber color-shifting pigment alone. The composition can produce surface colors that cannot be achieved using a dual-chamber color-shifting pigment alone. Therefore, the composition can display new colors that have never been seen before.

[0027] The composition exhibits improved color stability compared to compositions of dual cavity color shifting pigments having a thinner inner absorber layer.

[0028] The composition may include a dual-chamber color-shifting pigment. In one aspect, the composition may include a major amount of a dual-chamber color-shifting pigment to provide improved color performance and / or color stability. A major amount is understood herein to be greater than or equal to 50% by weight based on the total weight of the composition. In one aspect, the composition may include a dual-chamber color-shifting pigment in an amount of about 50% by weight to about 99% by weight, such as about 55% by weight to about 90% by weight, and as a further example, about 60% by weight to about 85% by weight based on the total weight of the composition.

[0029] In other aspects, the composition can include any amount of dual-chamber color-shifting pigment suitable for producing a new surface color. The composition can include the dual-chamber color-shifting pigment in an amount of about 20 wt %, such as about 40 wt %, such as about 60 wt %, and as a further example, about 80 wt %, based on the total weight of the composition. The composition can include any amount of dual-chamber color-shifting pigment, including any amount between 0 wt % and 100 wt %, based on the total weight of the composition.

[0030] The composition may include a single-chamber color-shifting pigment. In one aspect, the composition may include a minor amount of a single-chamber color-shifting pigment to adjust the color and / or improve color stability. Herein, a minor amount is understood to be less than 50% by weight based on the total weight of the composition. In one aspect, the composition may include a single-chamber color-shifting pigment in an amount of about 1% by weight to about 49% by weight, such as about 5% by weight to about 45% by weight, and as a further example, about 10% by weight to about 40% by weight based on the total weight of the composition.

[0031] In other aspects, the composition can include any amount of single cavity color shifting pigment suitable for producing a new surface color. The composition can include a single cavity color shifting pigment in an amount of about 20 wt %, such as about 40 wt %, such as about 60 wt %, and as a further example, about 80 wt %, based on the total weight of the composition. The composition can include any amount of single cavity color shifting pigment, including any amount between 0 wt % and 100 wt %, based on the total weight of the composition.

[0032] Single cavity color shifting pigments can be used in compositions to control brightness, hue, and chroma. Single cavity color shifting pigments can affect the color of a composition over angle. Single cavity color shifting pigments can include a core, a dielectric layer, and optionally an absorber layer. The layers of single cavity color shifting pigments will be discussed in detail below.

[0033] The dual cavity color shifting pigment may include a core, a first dielectric layer, an absorber layer, a second dielectric layer, and optionally a second absorber layer. The alternating dielectric layers and absorber layers may include any number of layers to form a stack. The stack of alternating dielectric layers and absorber layers may be present on one side of the core or on both sides of the core.

[0034] The first dielectric layer may comprise the same or different physical thickness as the second dielectric layer. The thickness of the second dielectric layer may be selected to match at least one of the reflectance peaks of the first dielectric layer. The physical thickness of the second dielectric layer may be from about 5 nm to about 1000 nm, for example from about 350 nm to 800 nm, and as a further example from about 380 nm to about 500 nm, and as a further example from about 590 nm to about 740 nm.

[0035] The layers in the single cavity color shifting pigment and the dual cavity color shifting pigment are disclosed below.

[0036] As described above, the core can include at least one layer selected from a reflective layer, a magnetic layer, and a combination thereof. In one aspect, the core is a reflective layer. In another aspect, the core is a magnetic layer. In another aspect, the core is a magnetic reflective layer. In yet another aspect, the core is a combination including a first reflective layer, a magnetic layer, and a second reflective layer. Materials for the core are discussed below.

[0037] The reflective layer can be a broadband reflector, for example, a spectral and Lambertian reflector (e.g., white TiO 2 ). The reflective layers may each independently comprise a metal, a non-metal and / or a metal blend or alloy. Unless otherwise indicated, the term "metal" or "metal layer" as used herein is intended to include all metals, metal blends and alloys, materials containing pure metals or metal alloys, compounds, compositions and / or layers.

[0038] In one example, the material for the reflective layer may include any material having reflective properties within the desired spectral range. For example, any material having a reflectivity range of 50% to 100% within the desired spectral range. An example of a reflective material may be aluminum, which has good reflective properties, is inexpensive, and is easy to form or deposit as a thin layer. Other materials may also be used instead of aluminum. For example, copper, silver, gold, platinum, palladium, nickel, cobalt, niobium, chromium, tin, and combinations, mixtures, or alloys of these or other metals may be used as reflective materials. In one aspect, the material for the reflective layer may be a white or light-colored metal. In other examples, the reflective layer may 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 with one or more of these materials.

[0039] The thickness of the reflective layer is in the range of about 5 nm to about 5000 nm, although this range should not be considered limiting. For example, a lower thickness can be selected so that the reflective layer provides a maximum transmittance of 0.8. Additionally or alternatively, for a reflective layer comprising aluminum, the minimum optical density (OD) at a wavelength of 550 nm can be about 0.1 to about 4.

[0040] The magnetic layer may include magnetically permeable materials, magnetically orientable materials, magnetic materials, and combinations thereof. Magnetic materials such as ferromagnetic and ferrimagnetic materials include, but are not limited to, nickel, cobalt, iron, gadolinium, terbium, dysprosium, erbium, and blends, alloys, or oxides thereof. Other examples of blends or alloys include, but are not limited to, Fe / Si, Fe / Ni, Fe / Co, Fe / Ni / Mo, Fe / Cr, Ni / Cr, and combinations thereof. In one aspect, the magnetic layer may include a polymer containing iron oxide particles. SmCo may also be used. 5 、NdCo 5 、Sm 2 Co17 、Nd 2 Fe 14 B. Sr 6 Fe 2 O 3 , TbFe 2 , Al-Ni-Co type hard magnets and their combinations, and Fe 3 O 4 、NiFe 2 O 4 、MnFe 2 O 4 、CoFe 2 O 4 The magnetic layer may be a spinel ferrite of the YIG or GdlG type, or a garnet of the YIG or GdlG type, and combinations thereof. In one aspect, the magnetic material may be a ferritic stainless steel. The magnetic material may be selected based on its reflective, absorptive or magnetic properties. The magnetic layer may be formed of a material having magnetic and non-magnetic particles, or magnetic particles in a non-magnetic medium, such as a cobalt-doped zinc oxide film deposited on a substrate. The magnetic layer may be a different layer or may be used as a reflective layer (magnetic reflective layer) or an absorber layer.

[0041] Although such a wide range of magnetic materials can be used, in one aspect, "soft" magnets can be used. As used herein, the term "soft magnet" refers to any material that exhibits ferromagnetic properties but has essentially zero residual magnetism after being exposed to a magnetic force. Soft magnets can exhibit a rapid response to an applied magnetic field, but have very low (coercive field (Hc) = 0.05-300 Oersted (Oe)) or zero magnetic characteristics, or maintain very low magnetic lines of force after removing the magnetic field. Similarly, as used herein, the term "hard magnet" (also called a permanent magnet) refers to any material that exhibits ferromagnetic properties and has a persistent residual magnetism after being exposed to a magnetic force. Ferromagnetic material is any material having a magnetic permeability significantly greater than 1 and exhibiting hysteresis properties. In one aspect, any magnetic material can be used for the magnetic layer as long as the material is capable of orienting the pigment in a magnetic field.

[0042] The magnetic layer can have a thickness ranging from about 10 nm to about 100 nm, for example, about 35 nm to about 45 nm, and as a further example, about 40 nm. The magnetic layer can be deposited to a thickness such that it is substantially opaque. In one aspect, the magnetic layer can be deposited to a thickness such that it is not substantially opaque.

[0043] Suitable materials for the dielectric layer include those having a "high" refractive index, defined herein as greater than about 1.65, and those having a "low" refractive index, defined herein as about 1.65 or less. The refractive index of the dielectric layer can be selected to provide a desired degree of color travel, where color travel can be defined as the change in hue angle measured in the L*a*b* color space with viewing angle. For example, gold (about 90 degree hue angle) can be achieved at optical thicknesses of 140 nm (2 / 4 wavelength), 280 nm (4 / 4 wavelength), and 430 nm (6 / 4 wavelength). Some colors are less attractive to the human eye due to low chroma or low brightness.

[0044] Examples of suitable high refractive index materials for the dielectric layer include zinc sulfide (ZnS), zinc oxide (ZnO), zirconium oxide (ZrO 2 ), titanium dioxide (TiO 2 )、Carbon (C), Indium oxide (In 2 O 3 ), indium tin oxide (ITO), tantalum pentoxide (Ta 2 O 5 ), cerium oxide (CeO 2 ), yttrium oxide (Y 2 O 3 ), europium oxide (Eu 2 O 3 ), iron oxides such as (II) iron (III) oxide (Fe 3 O 4 ) and ferric oxide (Fe 2 O 3 ), hafnium nitride (HfN), hafnium carbide (HfC), hafnium oxide (HfO 2 ), lanthanum oxide (La 2 O 3 ), magnesium oxide (MgO), neodymium oxide (Nd 2 O 3 ), praseodymium oxide (Pr 6 O 11 ), samarium oxide (Sm 2 O 3 ), antimony trioxide (Sb 2 O 3 ), silicon carbide (SiC), silicon nitride (Si 3 N 4 ), silicon monoxide (SiO), selenium trioxide (Se 2 O 3) , Tin Oxide (SnO 2 ), tungsten trioxide (WO 3 ) and their combinations, etc.

[0045] Examples of suitable low refractive index materials for the dielectric layer include silicon dioxide (SiO 2 ), aluminum oxide (Al 2 O 3 ), metal fluorides such as magnesium fluoride (MgF 2 ), aluminum fluoride (AlF 3 ), cerium fluoride (CeF 3 ), lanthanum fluoride (LaF 3 ), sodium aluminum fluoride (such as Na 3 AlF 6 Or Na 5 Al 3 F 14 ), Neodymium fluoride (NdF 3 ), samarium fluoride (SmF 3 ), barium fluoride (BaF 2 ), calcium fluoride (CaF 2 ), lithium fluoride (LiF), and combinations thereof, or any other low refractive index material having a refractive index of about 1.65 or less. For example, organic monomers and polymers can be used as low refractive index materials, including dienes or olefins, such as acrylates (e.g., methacrylates), perfluoroolefins, polytetrafluoroethylene (Teflon), fluorinated ethylene propylene (FEP), and combinations thereof, etc.

[0046] The dielectric layers may be deposited as a dielectric stack having a predetermined number of layers. In this example, the stack may include one or more layers of a low refractive index material and one or more layers of a high refractive index material. The layers having a low refractive index material (low refractive index layers) and the layers having a high refractive index material (high refractive index layers) may be alternating. For example, a high refractive index layer may be deposited on a reflective layer. A low refractive index layer may then be deposited on the high refractive index layer. The alternating layers of high refractive index layers and low refractive index layers may be repeated as many times as desired to form the dielectric layers as a dielectric stack. The alternating layers may be stacked in any order, for example, (H / L) may be arranged in a sequence of (H / L). n 、(H / L) n H or L (H / L) n The optical design can be made of a plurality of layers of dielectric materials. ...

[0047] In one aspect, the disclosed pigments (single cavity color shifting or dual cavity color shifting) can use a high refractive index material as an outer layer, avoiding the use of an absorber outer layer such as a second absorber layer (dual cavity color shifting). The high refractive index material as an outer layer can cause partial reflection with the liquid medium used to produce the color shifting colorant to produce a dual cavity. In this aspect, the liquid medium can have a different refractive index than the high refractive index material to cause partial reflection.

[0048] The absorber layer may be deposited on the dielectric layer. The absorber layer may independently include a metal, a non-metal or a metal blend or alloy. In one example, the material for the absorber layer may include any absorber material, including selectively absorbing materials and non-selectively absorbing materials. For example, the absorber layer may be made of a non-selectively absorbing metal material, which is deposited to a thickness where the layer is at least partially absorbing or semi-opaque. Examples of non-selectively absorbing materials may be gray metals such as chromium or nickel. An example of a selectively absorbing material may be copper or gold. In one aspect, the absorbing material may be chromium. Non-limiting examples of suitable absorber materials include metal absorbers such as chromium, aluminum, silver, nickel, palladium, platinum, titanium, vanadium, cobalt, iron, tin, tungsten, molybdenum, rhodium, niobium, copper, and other absorbers such as carbon, graphite, silicon, germanium, cermets, iron oxide or other metal oxides, metals mixed in a dielectric matrix, and other substances that can act as uniform or selective absorbers in the visible spectrum. Various combinations, mixtures, compounds or alloys of the above substances that can be used to form the absorber layer.

[0049] Examples of suitable alloys of the above absorber materials may include Inconel (Ni—Cr—Fe), stainless steel, Hastelloy (Ni—Mo—Fe; Ni—Mo—Fe—Cr; Ni—Si—Cu), and titanium-based alloys such as titanium mixed with carbon (Ti / C), titanium mixed with tungsten (Ti / W), titanium mixed with niobium (Ti / Nb), titanium mixed with silicon (Ti / Si), and combinations thereof. Other examples of suitable compounds for the absorber layer include, but are not limited to, titanium-based compounds such as titanium silicide (TiSi 2 ), titanium boride (TiB 2 ) and combinations thereof. Alternatively, the absorber layer may consist of a titanium-based alloy deposited in a Ti matrix, or may consist of Ti deposited in a matrix of a titanium-based alloy or blend. For example, the absorber layer may include chromium.

[0050] The absorber layer may also be composed of a magnetic material, such as a cobalt-nickel alloy or blend or an iron-chromium alloy or blend.The manufacture of a magnetic color-shifting device or structure may be simplified by reducing the amount of material required.

[0051] Depending on the optical constants of the absorber layer material and the desired peak shift, the absorber layer can be formed to have a physical thickness in the range of about 1 nm to about 50 nm, such as about 5 nm to about 10 nm. If there is more than one absorber layer, such as in a dual-cavity color shifting pigment, the absorber layers can be composed of the same material or different materials, and each layer can have the same or different physical thickness.

[0052] The composition may further include a liquid medium. The composition may be a color shifting colorant. The color shifting colorant may be, for example, an ink, a coating or a paint. Non-limiting examples of liquid media may include solvents, such as acetates such as ethyl acetate, propyl acetate and butyl acetate; acetone; water; ketones such as dimethyl ketone (DMK), methyl ethyl ketone (MEK), sec-butyl methyl ketone (SBMK), tert-butyl methyl ketone (TBMK), cyclopentane 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 malonic esters; heterocyclic solvents such as n-methylpyrrolidone; hydrocarbons such as toluene and xylene; coalescing solvents such as glycol ethers; and mixtures thereof. In one aspect, the liquid medium may be present in an amount of about 0% by weight to about 99.9% by weight relative to the total weight of the color shifting colorant, such as about 0.005% by weight to about 99% by weight, and as a further example about 0.05% by weight to about 90% by weight.

[0053] Each color shifting pigment (single cavity and / or dual cavity) disclosed can be altered, such as mechanically altered by crushing, etc. to form flakes, foils, sheets. The color shifting pigment can be formed into flakes, foils, or sheets having a size range of about 2 microns to about 40 microns. The color shifting pigment can have a D50 of 20 microns (50% of the pigment is greater than 20 microns and 50% of the pigment is less than 20 microns), a D0.01 of 4 microns (99.9% of the pigment is greater than 4 microns), and a D99.99 of 80 microns (0.01% of the pigment is less than 80 microns).

[0054] According to various embodiments, the single-cavity color-shifting pigment and the dual-cavity color-shifting pigment can each independently form a flake, foil or sheet. One of ordinary skill in the art will understand that each of the disclosed color-shifting pigments can include any number and any order of layers. The disclosed color-shifting pigments (single-cavity color-shifting pigments and / or dual-cavity color-shifting pigments) can each be symmetrical, that is, there are the same layers on each side of a central layer such as a core. The color-shifting pigments (single-cavity color-shifting pigments and / or dual-cavity color-shifting pigments) can each be asymmetrical, that is, there are different layers on each side of a central layer such as a core. In addition, the materials in any particular layer can be the same or different from the materials in any other layer. It is also contemplated that the color-shifting pigments disclosed herein may include additional layers, such as intermediate or intervening layers.

[0055] The compositions disclosed herein can provide a balance between cost and color performance. That is, a single cavity color shifting pigment can be manufactured at a lower cost, but exhibits low color performance. Alternatively, a dual cavity color shifting pigment can be manufactured at a higher cost, but exhibits high color performance. The disclosed compositions include two color shifting pigments that can be optimized to obtain the best characteristics of each pigment according to a specific application. In addition, the disclosed compositions can achieve surface colors that are not possible using either color shifting pigment alone.

[0056] The single cavity color shifting pigment may have a structure selected from any of the following structures, wherein the layers are defined as above:

[0057] Dielectric / core / dielectric;

[0058] absorber / dielectric / core / dielectric; or

[0059] Absorber / dielectric / core / dielectric / absorber.

[0060] The dual-chamber color shifting pigment may have a structure selected from any of the following structures, wherein the layers are defined as above:

[0061] dielectric / absorber / dielectric / core / dielectric;

[0062] absorber / dielectric / absorber / dielectric / core / dielectric;

[0063] dielectric / absorber / dielectric / core / dielectric / absorber;

[0064] absorber / dielectric / absorber / dielectric / core / dielectric / absorber;

[0065] dielectric / absorber / dielectric / core / dielectric / absorber / dielectric;

[0066] absorber / dielectric / absorber / dielectric / core / dielectric / absorber / dielectric; or

[0067] Absorber / dielectric / absorber / dielectric / core / dielectric / absorber / dielectric / absorber.

[0068] Also disclosed is a method for making a composition as described herein. The method may include mixing a dual-cavity color-shifting pigment and a single-cavity color-shifting pigment. A person skilled in the art may identify a target surface color, such as a pure red of low brightness (L*). A person skilled in the art may also develop a dual-cavity color-shifting pigment and draw its process path on a dual-cavity CIE L*a*b* chromaticity diagram. A person skilled in the art may also develop a single-cavity color-shifting pigment and draw its process path on a single-cavity CIE L*a*b* chromaticity diagram. A person skilled in the art may select a process path position for a composition having similar or identical brightness (L*) for each of the dual-cavity color-shifting pigment and the single-cavity color-shifting pigment to obtain a target surface color. A person skilled in the art may then mix different amounts of dual-cavity color-shifting pigments and single-cavity color-shifting pigments to match a specific a*b* target. For example, if a person skilled in the art requires high color performance, the composition may include a major amount of dual-cavity color-shifting pigments and a minor amount of single-cavity color-shifting pigments. If a person skilled in the art requires a new surface color that cannot be obtained with either pigment alone, the composition may include different amounts of dual-cavity color-shifting pigments and a minor amount of single-cavity color-shifting pigments. The single and dual cavity chromaticity diagrams show that many color ranges and L*a*b* combinations cannot be achieved by single cavity color shifting pigments or dual cavity color shifting pigment designs alone. The use of a mixture of two disclosed color shifting pigments opens up several areas that cannot be achieved by single cavity color shifting pigments or dual cavity color shifting pigments alone.

[0069] Example 1

[0070] The figure shows calculated optical properties where the interval markers on the curve defining the process path versus dielectric physical thickness represent 5 nm physical thickness intervals for theoretical magnesium fluoride dielectric layers, aluminum reflective layers, and chromium absorber layers with a refractive index of 1.38 in the visible spectrum.

[0071] To produce the most colorful red, the dielectric layer based on the use of magnesium fluoride as the dielectric material must not be thicker than 215 nm without a sharp drop in chromaticity at a hue angle of about 40 degrees. The desired surface color is red with a hue angle of nearly 30 degrees without any reduction in chromaticity or color stability.

[0072] The single-cavity color-shifting pigment in the composition includes: absorber-chromium (6.0nm) / dielectric-magnesium fluoride (440nm) / reflector-aluminum (40nm) / magnetic body-stainless steel (26nm) / reflector-aluminum (40nm) / dielectric-magnesium fluoride (440nm) / absorber-chromium (6.0nm). This exemplary single-cavity color-shifting pigment changes from magenta to green, such as Figure 1 and 2 The process path shown.

[0073] The dual-cavity color-shifting pigment (vermilion) includes: absorber-chromium (3.7 nm) / dielectric-magnesium fluoride (220 nm) / absorber-chromium (8.3 nm) / dielectric-magnesium fluoride (220 nm) / reflector-aluminum (40 nm) / magnetic body-stainless steel (26 nm) / reflector-aluminum (40 nm) / dielectric-magnesium fluoride (220 nm) / absorber-chromium (8.3 nm) / dielectric-magnesium fluoride (220 nm) / absorber-chromium (3.7 nm). This exemplary dual-cavity color-shifting pigment changes its surface color from vermilion (red) to gold with angle, as shown in FIG. Figure 3 and 4 The surface color shown in the process path.

[0074] The composition is made of a dual cavity color shifting pigment and a single cavity color shifting pigment. In a particular position, the a* and b* values ​​of the two disclosed color shifting pigments are the same, such as Figure 6 and 7 L* is different, as shown in Figure 8 As shown, the higher L* in the red spectrum of the single cavity pigment makes it a "dirty" red. The dual cavity color shifting pigment has a pure red color, but is darker and has a low L*. A mixture of a dual cavity color shifting pigment and a single cavity color shifting pigment can meet the option of adjusting the color to what is considered attractive. To achieve higher brightness in this case, the dual cavity color shifting pigment is made with a hue angle closer to orange, and the single cavity color shifting pigment is selected to be closer to a magenta color. A selected combination of the two disclosed pigments can produce a red color that is considered more attractive. It should be noted that mixing to this specific red color depends on the specific spectral response of the human eye. Orange light mixed with a small amount of blue is seen as red, provided that the blue energy level is low enough not to make it a magenta hue. Those skilled in the art have the skill to adjust the reflectance spectrum of the composition to a response close to the desired perceived color as a compromise. Pure red is a color that is extremely difficult to achieve through interference techniques. Ideally, it requires high reflection levels in the long wavelength part of the visible spectrum, and drops sharply to no reflection in any other part of the visible spectrum. This ideal situation cannot be achieved with either single cavity color shifting pigments or dual cavity color shifting pigments alone, and the combination of dual cavity color shifting pigments and single cavity color shifting pigments provides an additional means to obtain a color that is slightly closer to being considered pure red.

[0075] The weight of each pigment in the composition is varied, i.e., 0%, 20%, 40%, 60%, 80% and 100%, the total weight of the composition being equal to 100%, such as Figure 7 and 8As shown. Thus, for example, the composition includes 100% single-cavity pigments and 0% dual-cavity pigments (the "X" in the lower right corner is marked as "100%"). In another example, the composition includes 80% single-cavity pigments and 20% dual-cavity pigments. In another example, the composition includes 60% single-cavity pigments and 40% dual-cavity pigments. In another example, the composition includes 40% single-cavity pigments and 60% dual-cavity pigments (the "X" is marked as "40%"). In another example, the composition includes 20% single-cavity pigments and 80% dual-cavity pigments. In another example, the composition includes 0% single-cavity pigments and 100% dual-cavity pigments (the "X" is marked as "0%").

[0076] The composition exhibits a more colorful surface color that cannot be achieved by dual-chamber color-changing pigments or single-chamber color-changing pigments alone.

[0077] Example 2

[0078] The above composition was also prepared to obtain a blue surface color. The same single cavity color shifting pigment and the same dual cavity color shifting pigment were used in the same mixed composition, but the emphasis was on the color shift from violet to bronze at the other end of the wavelength spectrum. Fig. 9 Overlapping process paths for single cavity color shifting pigments, dual cavity color shifting pigments, and a mixture path are described. The composition exhibits surface colors that are unachievable using either single cavity color shifting pigments or dual cavity color shifting pigments alone.

[0079] The composition exhibits improved color performance compared to a single cavity color shifting material alone. The composition exhibits improved color stability compared to a dual cavity color shifting pigment with a thinner absorber layer. The mixing step further includes preparing a single cavity color shifting pigment and mapping a process path for the single cavity color shifting pigment. The mixing step further includes preparing a dual cavity color shifting pigment and mapping a process path for the dual cavity color shifting pigment. The mixing step further includes selecting a process path along the same brightness for each of the single cavity color shifting pigment and the dual cavity color shifting pigment to obtain a target surface color.

[0080] As can be seen from the foregoing description, those skilled in the art will appreciate that this teaching can be applied in various forms. Therefore, although these teachings have been described in conjunction with specific embodiments and examples thereof, the true scope of this teaching should not be limited thereto. Various changes and modifications may be made without departing from the scope of this teaching.

[0081] The scope of the present disclosure is to be interpreted broadly. The present disclosure is intended to disclose equivalents, means, systems and methods for implementing the devices, activities and mechanical modes of operation described herein. For each composition, pigment, method, means, mechanical element or mechanism disclosed, it is intended that the present disclosure encompasses the disclosed content and teaches equivalents, means, systems and methods for practicing many aspects, mechanisms and compositions disclosed herein. In addition, the present disclosure relates to compositions and many aspects, features and elements thereof. Such compositions can be dynamic in use and operation, and the present disclosure is intended to include equivalents, means, systems and methods for the use of compositions, and / or pigment production and many aspects thereof consistent with the description and spirit of the operations and functions disclosed herein. The claims of the present application should also be interpreted broadly.

[0082] The description of the invention in its many embodiments is merely exemplary in nature and thus variations that do not depart from the gist of the invention are intended to be within the scope of the invention. Such variations should not be regarded as a departure from the spirit and scope of the invention.

Claims

1. A composition comprising a dual-chamber color-shifting pigment; and a single-chamber color-shifting pigment.

2. The composition of claim 1, wherein the single cavity color shifting pigment comprises a core and a dielectric layer.

3. The composition of claim 2, wherein the core is selected from the group consisting of a reflective layer, a magnetic layer, and combinations thereof.

4. The composition of claim 2, wherein the single cavity color shifting pigment comprises a core, a dielectric layer, and an absorber layer.

5. The composition of claim 1, wherein the single cavity color shifting pigment may have a structure selected from any of the following structures: Dielectric / core / dielectric; absorber / dielectric / core / dielectric; or Absorber / dielectric / core / dielectric / absorber.

6. The composition of claim 1, wherein the single cavity color shifting pigment is symmetrical.

7. The composition of claim 1, wherein the single cavity color shifting pigment is asymmetric.

8. The composition of claim 1, wherein the dual cavity color shifting pigment comprises a core, a first dielectric layer, an absorber layer, and a second dielectric layer.

9. The composition of claim 1, wherein the dual-chamber color shifting pigment can have a structure selected from any of the following structures: dielectric / absorber / dielectric / core / dielectric; absorber / dielectric / absorber / dielectric / core / dielectric; dielectric / absorber / dielectric / core / dielectric / absorber; absorber / dielectric / absorber / dielectric / core / dielectric / absorber; dielectric / absorber / dielectric / core / dielectric / absorber / dielectric; absorber / dielectric / absorber / dielectric / core / dielectric / absorber / dielectric; or Absorber / dielectric / absorber / dielectric / core / dielectric / absorber / dielectric / absorber.

10. The composition of claim 1, wherein the dual cavity color shifting pigment is present in the composition in a major amount.

11. The composition of claim 1, wherein the dual cavity color shifting pigment is present in the composition in an amount ranging from about 50% to about 99% by weight based on the total weight of the composition.

12. The composition of claim 1, wherein the single cavity color shifting pigment is present in the composition in a minor amount.

13. The composition of claim 1, wherein the single cavity color shifting pigment is present in the composition in an amount ranging from about 1% to about 49% by weight based on the total weight of the composition.

14. The composition of claim 1, wherein the composition exhibits a color that is not achievable with either the dual cavity color shifting pigment or the single cavity color shifting pigment alone.

15. A method of forming a composition, comprising: Mix dual cavity color shifting pigments with single cavity color shifting pigments.

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