CN116925569A - Optical pigment and preparation method thereof - Google Patents

Abstract

The application provides an optical pigment and a preparation method thereof. The optical pigment comprises: an opaque substrate, a first dielectric layer and a second dielectric layer; wherein, the first dielectric layer is coated on the surface of the opaque substrate; the second medium layer is coated on the surface of the first medium layer, and the refractive index of the first medium layer is smaller than that of the second medium layer. The optical pigment has better hiding power, can show more obvious effect of angle-dependent color variation, has higher tolerance temperature, and greatly increases the application range of the optical pigment.

Description

Optical pigment and preparation method thereof

Technical Field

The application relates to the field of novel optical pigments, in particular to an optical pigment and a preparation method thereof.

Background

The color is usually realized by using organic pigments or chemical dyes, and the traditional organic pigments or chemical dyes are rich in color and simple to process, so that the price is low; however, they tend to be less weather resistant, easily denatured under ultraviolet light, humid oxygen enrichment, etc., and have a shorter life. Accordingly, there is increasing interest in the field of inorganic pigments. Among them, pearlescent pigments are one of the most rapidly developing and widely accepted types of special optical effect pigments by users.

The pearlescent pigment is coated with one or more layers of metal oxides on the mica flake, and forms a color effect through the interference effect of a multi-layer nano film layer structure on incident light; compared with the traditional pigment, the special pigment structure has the advantages of high brightness, good weather resistance, high temperature resistance, color change along with angles, flash point effect and the like, and is widely applied to the fields of cosmetics, paint, printing ink, printing and dyeing and the like. However, the optical absorption of materials involved in pearlescent is weak; thus, pearlescent pigments tend not to be hiding, and applications in some areas where hiding color is desired are greatly limited.

For this reason, color aluminum pigment gradually goes into the eyes of people; the color aluminum pigment realizes the interference color effect by coating metal oxide nano film layers such as ferric oxide and the like on an opaque aluminum sheet. The color aluminum pigment can solve the covering power problem of the pearlescent pigment to a certain extent; however, the color of the colored aluminum is limited to yellow, orange, red, brown and other warm tone effects due to the strong absorption of the used ferric oxide in blue and green wave bands; and the characteristic that the color aluminum pigment changes color along with angles is inhibited to a great extent because the refractive index of the ferric oxide is too high.

Disclosure of Invention

The optical pigment provided by the application has better covering property and better effect-changing property.

In order to solve the technical problems, the first technical scheme adopted by the application is as follows: an optical pigment is provided. The optical pigment comprises: an opaque substrate, a first dielectric layer and a second dielectric layer; wherein, the first dielectric layer is coated on the surface of the opaque substrate; the second medium layer is coated on the surface of the first medium layer, and the refractive index of the first medium layer is smaller than that of the second medium layer.

Wherein the first dielectric layer covers the outer surface of the whole opaque substrate; the second dielectric layer covers the entire outer surface of the first dielectric layer.

The refractive index of the first dielectric layer is smaller than the threshold value, and the refractive index of the second dielectric layer is larger than the threshold value; wherein the threshold value is in the range of 1.1-2.8.

Wherein the thickness of the first dielectric layer is 5-1000nm, and the thickness of the second dielectric layer is 5-1000nm.

Wherein the opaque substrate has an average particle diameter of 10-100 μm and an average thickness of 0.1-5 μm.

Wherein, the opaque substrate is one or more of graphite sheet, aluminum sheet, silver sheet, gold sheet, titanium sheet, nickel sheet, iron sheet, copper sheet, tin sheet and other metals or alloy materials thereof.

The first dielectric layer is made of one or more of silicon dioxide, aluminum oxide, boron trioxide, magnesium oxide, magnesium fluoride, yttrium oxide and silicon monoxide; the second dielectric layer is made of one or more of titanium dioxide, tin dioxide, ferric oxide, cuprous oxide, ferric oxide, molybdenum oxide, tungsten oxide, zinc oxide, zirconium oxide and tantalum pentoxide.

In order to solve the technical problems, a second technical scheme adopted by the application is as follows: a method for preparing an optical pigment is provided. The method comprises the following steps: adding the opaque substrate into deionized water according to the mass ratio of 3% -10%, stirring and heating to 60-90 ℃, regulating the pH value to 4-9, metering soluble inorganic salt corresponding to the first medium material, stirring for a first preset time, filtering and flushing to obtain a first filtering product, so as to form a first medium layer on the surface of the opaque substrate; adding the first filtering product into deionized water according to the mass ratio of 3% -15%, stirring and heating to 60-90 ℃, regulating the pH value to 1-4, metering the soluble inorganic salt corresponding to the second medium material, stirring for a second preset time, filtering and flushing to obtain a second filtering product, so as to form a second medium layer on the surface of the first medium layer; wherein the refractive index of the first dielectric material is smaller than the refractive index of the second dielectric material.

Wherein the method further comprises: calcining the second filtered product at a temperature of not less than 600 ℃.

Wherein, the opaque substrate is one or more of graphite sheet, aluminum sheet, silver sheet, gold sheet, titanium sheet, nickel sheet, iron sheet, copper sheet, tin sheet or alloy material thereof; the first dielectric material is one or more of silicon dioxide, aluminum oxide, boron oxide, magnesium fluoride, yttrium oxide, silicon monoxide and the like; the second dielectric material is one or more of titanium dioxide, tin dioxide, ferric oxide, cuprous oxide, ferroferric oxide, molybdenum oxide, tungsten oxide, zinc oxide, zirconium oxide and tantalum pentoxide.

The embodiment of the application provides an optical pigment and a preparation method thereof. The opaque substrate is arranged, so that the optical pigment has better hiding power due to higher light-shielding property; in addition, the first medium layer is coated on the surface of the opaque substrate, the second medium layer is coated on the surface of the first medium layer, and the refractive index of the first medium layer is smaller than that of the second medium layer, so that the optical pigment can display a more obvious effect of angle-dependent color variation by controlling the thickness of the first medium layer with low refractive index, and meanwhile, the second medium layer with high refractive index displays a color with high saturation, so that the optical pigment can be suitable for the color field requiring higher covering property. In addition, the optical pigment has a relatively simple structure only by coating the first dielectric layer and the second dielectric layer on the surface of the opaque substrate, so that the process steps are simplified.

Drawings

FIG. 1 is a schematic diagram of an optical pigment according to an embodiment of the present application;

fig. 2 is a flowchart of a method for preparing an optical pigment according to an embodiment of the present application.

Detailed Description

The following description of the embodiments of the present application will be made clearly and fully with reference to the accompanying drawings, in which it is evident that the embodiments described are only some, but not all embodiments of the application. All other embodiments, which can be made by those skilled in the art based on the embodiments of the application without making any inventive effort, are intended to be within the scope of the application.

The terms "first," "second," "third," and the like in this disclosure are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first", "a second", and "a third" may explicitly or implicitly include at least one such feature. In the description of the present application, the meaning of "plurality" means at least two, for example, two, three, etc., unless specifically defined otherwise. All directional indications (such as up, down, left, right, front, back … …) in embodiments of the present application are merely used to explain the relative positional relationship, movement, etc. between the components in a particular gesture (as shown in the drawings), and if the particular gesture changes, the directional indication changes accordingly. Furthermore, the terms "comprise" and "have," as well as any variations thereof, are intended to cover a non-exclusive inclusion. For example, a process, method, system, article, or apparatus that comprises a list of steps or elements is not limited to only those listed steps or elements but may include other steps or elements not listed or inherent to such process, method, article, or apparatus.

Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the application. The appearances of such phrases in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. Those of skill in the art will explicitly and implicitly appreciate that the embodiments described herein may be combined with other embodiments.

The existing optical color cannot simultaneously give consideration to the characteristics of better light-shielding property and effect, so that the existing optical pigment such as pearlescent pigment has the advantages of high brightness, good weather resistance, high temperature resistance, effect of changing color with angle, flash point effect and the like; however, pearlescent pigments often do not have hiding power, and are limited to a great extent in some fields requiring hiding power; the color aluminum pigment can solve the covering power problem of the pearlescent pigment to a certain extent; however, the characteristic that the color aluminum pigment changes color with angle is greatly inhibited due to the higher refractive index of the ferric oxide used by the color aluminum pigment.

Therefore, the embodiment of the application provides the optical pigment which not only has effect of flop and rich colors, but also has better covering property; meanwhile, the opaque substrate material tolerates higher temperature, so that the optical pigment has better high-temperature resistance and wider application range.

The present application will be described in detail with reference to the accompanying drawings and examples.

Referring to fig. 1, fig. 1 is a schematic structural diagram of an optical pigment according to an embodiment of the application. In this embodiment, the optical pigment comprises an opaque substrate 10, a first dielectric layer 11 and a second dielectric layer 12. Wherein, the first dielectric layer 11 is coated on the surface of the opaque substrate 10, and the second dielectric layer 12 is coated on the surface of the first dielectric layer 11.

Wherein the opaque substrate 10 may have an average particle diameter of 10 to 100 μm and an average thickness of 0.1 to 5 μm. By the arrangement, the diameter thickness of the opaque substrate 10 can be larger, so that the first dielectric layer 11 is easier to coat on the surface of the opaque substrate 10, and the coating rate is higher. In particular, the opaque substrate 10 may be a metal sheet or a graphite sheet; the metal sheet may be one or more of aluminum sheet, silver sheet, gold sheet, titanium sheet, nickel sheet, iron sheet, copper sheet, tin sheet or alloy material thereof. These opaque substrates 10 not only have metallic luster per se, but also the opaque substrates 10 exhibit an opaque visual effect, and thus have better hiding power and better hiding effect. Meanwhile, the opaque substrates 10 have better high temperature resistance due to higher melting point, so that the optical pigment has better high temperature resistance effect, and can be applied to the fields of ceramics, glass, building materials and the like which need high temperature. In addition, by selecting the opaque substrates 10 made of different materials, the optical pigment can have special functions, for example, the opaque substrates 10 with magnetism such as iron, cobalt, nickel and the like are selected, and the optical pigment can have magnetism, so that the optical pigment can be applied to the special fields such as 3D anti-counterfeiting ink and the like.

The material of the first dielectric layer 11 is specifically one or more of silicon dioxide, aluminum oxide, boron trioxide, magnesium oxide, magnesium fluoride, yttrium oxide and silicon monoxide, so that a compact protective layer is formed on the surface of the opaque substrate 10, and the opaque substrate 10 coated inside the first dielectric layer 11 is prevented from being corroded or denatured.

Specifically, the refractive index of the first dielectric layer 11 is smaller than a threshold value, and the threshold value ranges from 1.1 to 2.8; the refractive index of the first medium layer 11 is smaller, so that the optical pigment has angle sensitive characteristic, namely has visual effect of angle-dependent color, and different observation angles, and the pigment presents different colors of brightness and hue. Specifically, the first dielectric layers 11 with different thicknesses have different angle-sensitive characteristics and brightness for the optical pigment. Wherein, the thicker the thickness is, the better the angle sensitivity characteristic is, and the more obvious the effect of the flop is; therefore, the degree of flop of the optical pigment can be changed by adjusting the thickness of the first dielectric layer 11; in a specific embodiment, the first dielectric layer 11 with a preset thickness may be selected according to the requirement, so that the flop effect and the color brightness of the optical pigment meet the requirement.

Specifically, the thickness of the first dielectric layer 11 ranges from 5 nm to 1000nm, and the specific thickness can be set according to actual needs; for example, the effect of flop is more pronounced, a thickness of 200nm may be preferred, if the effect of flop is not significant, a thickness of 20nm may be preferable, which is not particularly limited.

Of course, in some embodiments, in order to meet some special requirements, for example, no flop effect or only a weak flop effect is required, the thickness of the first dielectric layer 11 may be set small, or even the first dielectric layer 11 may not be set, and the second dielectric layer 12 may be directly coated on the outer surface of the opaque substrate 10.

The second dielectric layer 12 covers the entire outer surface of the first dielectric layer 11 to form a second protective layer on the surface of the opaque substrate 10, so as to further protect the opaque substrate 10 from corrosion or denaturation, and further improve the stability of the optical pigment.

Specifically, the refractive index of the second dielectric layer 12 may be greater than a threshold, the threshold may range from 1.1 to 2.8, and the refractive index of the second dielectric layer 12 is greater than the refractive index of the first dielectric layer 11; the incident light generates multiple reflection, transmission and refraction at the interface of the second medium layer 12, so that the pigment generates strong pearlescent luster; meanwhile, the refractive index of the second dielectric layer 12 is greater than a threshold value, which may range from 1.1 to 2.8, so that the color saturation of the optical pigment is higher.

In particular, the thickness of the second dielectric layer 12 may be selected according to actual requirements to meet the color requirements of the optical pigment in the embodiment, because the second dielectric layers 12 with different thicknesses respectively correspond to different colors of the optical pigment. Specifically, the thickness of the second dielectric layer 12 may be 5-1000nm, and the thickness is selected in a larger range, so that the color selection range of the optical pigment is wider, and the specific thickness can be set according to the color requirement.

Specifically, the second dielectric layer 12 is made of one or more of titanium dioxide, tin dioxide, ferric oxide, cuprous oxide, ferric oxide, molybdenum oxide, tungsten oxide, zinc oxide, zirconium oxide, and tantalum pentoxide. The second medium layer 12 with different materials can make the color tone of the optical pigment different, so that the optical pigment can present different color tones, the color range is wider, and the color types are more, and the materials of the second medium layer 12 can be specifically selected according to the needs to obtain the optical pigment with corresponding color. Therefore, the color of the optical pigment can be adjusted by providing the second dielectric layer 12 of different materials or different thicknesses to obtain a desired color.

In this embodiment, the thickness of the first dielectric layer 11 may be greater than that of the second dielectric layer 12, so that the effect of flop of the optical pigment is more obvious. In other embodiments, the thickness of the first dielectric layer 11 may be smaller than or equal to the thickness of the second dielectric layer 12, so as to meet the requirements of different flop effects. Of course, to meet some special requirements, for example, no effect or only a weak effect is required, the thickness of the first dielectric layer 11 may be very small, even 0, that is, the first dielectric layer 11 is not provided, and the second dielectric layer 12 with a certain thickness is directly coated on the outer surface of the opaque substrate 10.

According to the optical pigment provided by the embodiment, the first medium layer 11 and/or the second medium layer 12 with the nanoscale thickness are/is coated on the outer surface of the opaque substrate 10, so that a color layer with a specific nano structure is formed on the surface of the opaque substrate 10, and meanwhile, the color layer with the nano structure also has the function of protecting the opaque substrate 10, so that the optical pigment has the weather-proof, high-temperature-resistant and acid-alkali-resistant properties; for example, the opaque substrate 10 made of nickel, titanium or graphite is coated to enable the optical pigment to resist the temperature of more than 800 ℃, so that the optical pigment can be applied to high-temperature coloring in the fields of ceramics, building materials, glass and the like. Specifically, the optical pigment has high light-shielding property by exhibiting an opaque effect through the opaque substrate 10, so that the optical pigment has good hiding power; meanwhile, one or more of graphite sheets, aluminum sheets, silver sheets, gold sheets, titanium sheets, nickel sheets, iron sheets, copper sheets, tin sheets or alloy materials thereof are selected as the opaque substrate 10, so that the opaque substrate 10 has better high-temperature resistance, and the optical pigment has better high-temperature resistance and can be applied to the fields requiring high temperature, such as ceramics, glass, building materials and the like. In addition, by coating the first dielectric layer 11 on the surface of the opaque substrate 10, coating the second dielectric layer 12 on the surface of the first dielectric layer 11, and making the refractive index of the first dielectric layer 11 smaller than that of the second dielectric layer 12, the optical pigment can exhibit the effect of flop through the first dielectric layer 11 with low refractive index, and the effect degree of flop of the optical pigment can be changed by adjusting the thickness of the first dielectric layer by making the thickness of the first dielectric layer 11 within the range of 0-1000 nm; the second medium layer 12 with high refractive index presents high saturation color, and the thickness range of the second medium layer 12 is 5-1000nm, so that optical pigments with different colors can be obtained by adjusting the thickness of the second medium layer 12, and the color range is wider, so that the color variety of the optical pigment is richer. In addition, the optical pigment has a relatively simple structure by only coating the first dielectric layer 11 and the second dielectric layer 12 on the surface of the opaque substrate, thereby simplifying the process steps.

In a specific embodiment, the above-mentioned optical pigments can be produced by the following optical pigment production method.

Referring to fig. 2, fig. 2 is a flowchart of a method for preparing an optical pigment according to an embodiment of the application. In this embodiment, there is provided a method for producing an optical pigment, the method comprising:

step S1: adding the opaque substrate 10 into deionized water according to the mass ratio of 3% -10%, stirring and heating to 60-90 ℃, adjusting the pH value to 4-9, metering the soluble inorganic salt corresponding to the first medium material, stirring for a first preset time, filtering and flushing to obtain a first filtering product, and forming a first medium layer 11 on the surface of the opaque substrate 10.

Wherein, the opaque substrate 10 can be selected from metal sheet and/or graphite sheet; the metal sheet can be one or more of aluminum sheet, silver sheet, gold sheet, titanium sheet, nickel sheet, iron sheet, copper sheet, tin sheet and other metals or alloy materials thereof. The opaque substrate 10 has good hiding power and high temperature resistance, and can lead the finally obtained optical pigment to have good hiding effect and high temperature resistance. Meanwhile, through the selection of different opaque substrate 10 materials, the additional special functionality of the optical pigment can be realized, for example, if the magnetic opaque substrate 10 materials such as iron, cobalt, nickel and the like are selected, the finally prepared optical pigment can have magnetism and can be used as special 3D anti-counterfeiting ink.

In a specific embodiment, the opaque substrate 10 is put into deionized water at a mass ratio of 3% -10%, and stirred and heated to 60-90 ℃ to form an opaque substrate 10 suspension, so that the opaque substrate 10 is uniformly distributed in the deionized water, and the first medium is deposited on the outer surface of the opaque substrate 10 as completely and uniformly as possible in the subsequent preparation process.

And then, according to the requirements of the actual toner brightness and the angle sensitivity characteristic, the adding amount of the soluble inorganic salt corresponding to the first dielectric material can be adjusted to adjust the thickness of the finally formed first dielectric layer 11, so that the adjustment of the toner brightness and the angle sensitivity characteristic is realized to form the first dielectric layer 11 with the preset thickness. The first dielectric material may be one or more of silicon dioxide, aluminum oxide, boron oxide, magnesium fluoride, yttrium oxide, silicon monoxide, etc. The refractive index of the first dielectric material is less than a threshold value in the range of 1.1-2.8. The first dielectric layer 11 has a predetermined thickness of 5-1000nm, different thicknesses, the angular sensitivity of the optical pigments finally obtained is different, i.e. the effect of the flop is different, in general, the intensity of the effect of the flop is proportional to the thickness of the first dielectric layer 11, i.e. the thicker the thickness, the more pronounced the effect of the flop, under the condition that the refractive index of the first dielectric layer 11 is unchanged.

It should be noted that, the above metering of the soluble inorganic salt corresponding to the first medium refers to the mass of the soluble inorganic salt corresponding to the first medium material required for the first medium layer 11 corresponding to the preset thickness. In some embodiments, to meet some special requirements, if no effect or only a weak effect is required, the thickness of the corresponding first dielectric layer 11 may be very small, even 0, that is, the first dielectric layer 11 is not required to be formed, and the soluble inorganic salt corresponding to the first dielectric material is not required to be added.

Generally, the soluble inorganic salt corresponding to the dielectric material may be one or more, which is related to the material of the specific dielectric layer, and may be selected according to the requirement.

Specifically, in the process of adding the soluble inorganic salt corresponding to the first medium, sodium hydroxide or dilute hydrochloric acid solution with a certain concentration can be added at the same time, so as to ensure that the pH value in the solution system is constant. The specific concentration of sodium hydroxide or dilute hydrochloric acid can be prepared according to the requirement. After the charging is completed, stirring at constant temperature for a first preset time; the first preset time can be 10-30min, and can be flexibly adjusted according to actual needs, and the first preset time is not particularly limited.

Step S2: adding the first filtering product into deionized water according to the mass ratio of 3% -15%, stirring and heating to 60-90 ℃, regulating the pH value to 1-4, metering soluble inorganic salt corresponding to the material of the second medium layer, stirring for a second preset time, filtering and flushing to obtain a second filtering product, so as to form a second medium layer 12 on the surface of the first medium layer 11.

The first filtering product is added into deionized water according to the mass ratio of 3% -15%, the temperature is raised to 60-90 ℃ through stirring, so that a second filtering product suspension is formed, the second filtering product is uniformly distributed in the deionized water, and the second oxide is deposited on the outer surface of the first medium layer 11 as completely and uniformly as possible in the subsequent process.

Specifically, the refractive index of the second dielectric material is larger than that of the first dielectric layer material; and the refractive index of the second dielectric material may specifically be greater than a threshold value, which may range from 1.1 to 2.8. The second dielectric material can be one or more of titanium dioxide, tin dioxide, ferric oxide, cuprous oxide, ferric oxide, molybdenum oxide, tungsten oxide, zinc oxide, zirconium oxide, tantalum pentoxide and the like. In a specific implementation process, the addition amount of the soluble inorganic salt corresponding to the second dielectric material may be set according to the color of the optical pigment actually required, so as to form the second dielectric layer 12 with a preset thickness, thereby obtaining the optical pigment with the corresponding color. It will be appreciated that different thicknesses of the second dielectric layer 12 correspond to different colors of optical pigments. In a specific embodiment, the second dielectric layer 12 has a predetermined thickness of 5-1000nm.

It should be noted that, similar to the first dielectric layer 11, the metering refers to the mass of the soluble inorganic salt corresponding to the second dielectric material required for the second dielectric layer 12 corresponding to the preset thickness. Specifically, the soluble inorganic salt corresponding to the second medium material is a soluble inorganic salt containing a metal element in the second medium material, for example, the soluble inorganic salt corresponding to titanium dioxide may be titanium tetrachloride.

In the same step S1, in the process of adding the soluble inorganic salt corresponding to the second medium material, sodium hydroxide or dilute hydrochloric acid solution with a certain concentration can be added at the same time so as to ensure that the pH value in the solution system is constant. After the addition is complete, the second preset time may be stirred at constant temperature. The second preset time may be the same as or different from the first preset time, and may be specifically and flexibly adjusted according to actual needs, which is not particularly limited.

In a specific implementation process, the preparation method of the optical pigment further comprises the following steps:

step S3: calcining the second filtered product at a temperature of not less than 600 ℃.

Specifically, the second filtering product is placed in an oven to be dried at the temperature of 100-150 ℃, and then calcined at the high temperature of not lower than 600 ℃ for 30-60 minutes, so as to promote the crystal form transformation of the material of the second medium layer 12, further improve the refractive index of the second medium layer 12, and further improve the color saturation of the finally obtained optical pigment.

The preparation method of the optical pigment provided in this embodiment is to coat the nano-structure film layer made of multi-layer dielectric layer on the outer surface of the opaque substrate 10 by chemical liquid deposition. Wherein, the opaque substrate 10 is adopted to show an opaque effect and has higher light-shielding property, so that the finally obtained optical pigment has better hiding power; meanwhile, one or more of graphite sheets, aluminum sheets, silver sheets, gold sheets, titanium sheets, nickel sheets, iron sheets, copper sheets, tin sheets or alloy materials thereof with better high temperature resistance are adopted as the opaque substrate 10, so that the optical pigment has better high temperature resistance and can be applied to the fields requiring high temperature, such as ceramics, glass, building materials and the like. By coating the first medium layer 11 on the surface of the opaque substrate 10 and coating the second medium layer 12 on the surface of the first medium layer 11, the refractive index of the first medium layer 11 is smaller than that of the second medium layer 12, so that the optical pigment can show effect of flop through the first medium layer 11 with low refractive index, and show color with high saturation through the second medium layer 12 with high refractive index, and the optical pigment can be suitable for the field requiring covering color. Specifically, the brightness and angle sensitivity of the optical pigment can be adjusted by adjusting the thickness of the first dielectric layer 11, and the color of the optical pigment can be adjusted by adjusting the thickness of the second dielectric layer 12 or selecting the corresponding material of the second dielectric layer 12, so that the color variety of the optical pigment is richer.

Specific examples of the preparation method of the optical pigment are as follows:

example 1:

40 is added into a 1L reaction kettle0ml deionized water, and 15g of flaky titanium powder is added, wherein the thickness of the titanium flakes is 0.25um, the average particle size is 60 mu m, and the mixture is stirred and heated to 75 ℃; the pH was adjusted to 8.1 using 5% by mass of dilute hydrochloric acid and 10% by mass of NaOH solution, 40ml of 20% by mass of Na was metered in dropwise ₂ SiO ₃ ·9H ₂ O solution is added dropwise with 5 percent of dilute hydrochloric acid to maintain constant pH, and after the addition is completed, the mixture is stirred for 30 minutes at constant temperature to form SiO on the outer surface of the titanium sheet ₂ The layers were filtered and rinsed 3 times with water to give a first filtered product, wherein SiO ₂ The thickness of the layer was about 20nm.

The first filtered product was added to 400ml deionized water, stirred and added to 75 ℃. The pH of the suspension was adjusted to 2.0 using 5% by mass of dilute hydrochloric acid and 10% by mass of NaOH solution, and 150ml of TiCl having a concentration of 2mol/L was metered in dropwise ₄ The solution was simultaneously added dropwise with 25% by mass of NaOH solution to maintain the pH constant, and after the addition was completed, stirred at constant temperature for 30 minutes to obtain a solution containing SiO ₂ Forming TiO on the outer surface of the layer ₂ The layers were filtered and rinsed 3 times with water to finally obtain a second filtered product, wherein TiO ₂ The thickness of the layer was about 150nm.

And (3) drying the final second filtered product in a baking oven at 120 ℃, and calcining at 800 ℃ for 1h to obtain the blue pigment.

Example 2:

400ml of deionized water is added into a 1L reaction kettle, and 15g of flaky titanium powder is added, wherein the thickness of titanium flakes is 0.25um, the average particle size is 60 mu m, and the mixture is stirred and heated to 75 ℃; the pH was adjusted to 8.1 using 5% by mass of dilute hydrochloric acid and 10% by mass of NaOH solution, 40ml of 20% by mass of Na was metered in dropwise ₂ SiO ₃ ·9H ₂ O solution is added dropwise with 5 percent of dilute hydrochloric acid to maintain constant pH, and after the addition is completed, the mixture is stirred for 30 minutes at constant temperature to form SiO on the outer surface of the titanium sheet ₂ The layers were filtered and rinsed 3 times with water to give a first filtered product, wherein SiO ₂ The thickness of the layer was about 20nm.

Adding the first filtered product into 400ml deionized waterStirred and added to 75 ℃. The pH of the suspension was adjusted to 2.0 using 5% by mass of dilute hydrochloric acid and 10% by mass of NaOH solution, and 200ml of TiCl having a concentration of 2mol/L was metered in dropwise ₄ The solution was simultaneously added dropwise with 25% by mass of NaOH solution to maintain the pH constant, and after the addition was completed, stirred at constant temperature for 30 minutes to obtain a solution containing SiO ₂ Forming TiO on the outer surface of the layer ₂ The layers were filtered and rinsed 3 times with water to finally obtain a second filtered product, wherein TiO ₂ The thickness of the layer was about 200nm.

And (3) drying the final second filtered product in a 120 ℃ oven, and calcining at 800 ℃ for 1h to obtain the golden pigment.

Comparative example 1 and example 2: the second dielectric layer 12 of the optical pigment finally obtained in example 1 had a thickness of 150nm and a color of blue; the second dielectric layer 12 of the optical pigment finally obtained in example 2 had a thickness of 200nm and a gold color. It is easy to find that, under the same conditions, the thickness of the second dielectric layer 12 is different, and the color of the finally obtained optical pigment is different, that is, the color exhibited by the optical pigment is different through the second dielectric layer 12 with different thickness, and the required color can be obtained through adjusting the thickness of the second dielectric layer 12.

Example 3:

400ml of deionized water is added into a 1L reaction kettle, and 15g of flaky titanium powder is added, wherein the thickness of titanium flakes is 0.25um, the average particle size is 60 mu m, and the mixture is stirred and heated to 75 ℃; the pH was adjusted to 8.1 using 5% by mass of dilute hydrochloric acid and 10% by mass of NaOH solution, 400ml of 20% by mass of Na was metered in dropwise ₂ SiO ₃ ·9H ₂ O solution is added dropwise with 5 percent of dilute hydrochloric acid to maintain constant pH, and after the addition is completed, the mixture is stirred for 30 minutes at constant temperature to form SiO on the outer surface of the titanium sheet ₂ The layers were filtered and rinsed 3 times with water to give a first filtered product, wherein SiO ₂ The thickness of the layer was about 200nm.

The first filtered product was added to 400ml deionized water, stirred and added to 75 ℃. The pH of the suspension is adjusted by using 5 percent of dilute hydrochloric acid and 10 percent of NaOH solutionTo 2.0, 50ml of TiCl at a concentration of 2mol/L are metered in ₄ The solution was simultaneously added dropwise with 25% by mass of NaOH solution to maintain the pH constant, and after the addition was completed, stirred at constant temperature for 30 minutes to obtain a solution containing SiO ₂ Forming TiO on the outer surface of the layer ₂ The layers were filtered and rinsed 3 times with water to finally obtain a second filtered product, wherein TiO ₂ The thickness of the layer was about 50nm.

And (3) drying the final second filtering product in a baking oven at 120 ℃, and calcining at 800 ℃ for 1h to obtain the blue-violet color-changing pigment with different effect.

Example 4:

400ml of deionized water is added into a 1L reaction kettle, and 15g of flaky titanium powder is added, wherein the thickness of titanium flakes is 0.25um, the average particle size is 60 mu m, and the mixture is stirred and heated to 75 ℃; the pH was adjusted to 8.1 using 5% by mass of dilute hydrochloric acid and 10% by mass of NaOH solution, and 40ml of 20% by mass of Na was metered in dropwise ₂ SiO ₃ ·9H ₂ O solution is added dropwise with 5 percent of dilute hydrochloric acid to maintain constant pH, and after the addition is completed, the mixture is stirred for 30 minutes at constant temperature to form SiO on the outer surface of the titanium sheet ₂ The layers were filtered and rinsed 3 times with water to give a first filtered product, wherein SiO ₂ The thickness of the layer was about 20nm.

The first filtered product was added to 400ml deionized water, stirred and added to 75 ℃. The pH of the suspension is adjusted to 2.0 by using 5% by mass of dilute hydrochloric acid and 10% by mass of NaOH solution, and 50ml of TiCl with the concentration of 2mol/L is metered and added dropwise ₄ The solution was simultaneously added dropwise with 25% by mass of NaOH solution to maintain the pH constant, and after the addition was completed, stirred at constant temperature for 30 minutes to obtain a solution containing SiO ₂ Forming TiO on the outer surface of the layer ₂ The layers were filtered and rinsed 3 times with water to finally obtain a second filtered product, wherein TiO ₂ The thickness of the layer was about 50nm.

And (3) drying the final second filtered product in a baking oven at 120 ℃, and calcining at 800 ℃ for 1h to obtain the light blue pigment with no different angle.

Comparative example 3 and example 4: the thickness of the first dielectric layer 11 of the optical pigment finally obtained in example 3 was 200nm, and the color was bluish violet and flop; the thickness of the first dielectric layer 11 of the optical pigment finally obtained in example 4 was 20nm, the color was light blue, and the effect was not different; it is easy to find that the thickness of the first dielectric layer 11 is different and the effect of the flop of the obtained optical pigment is different under the same other conditions; when the thickness of the first dielectric layer 11 is relatively thick, the angle sensitivity characteristic of the finally obtained optical pigment is stronger, and the effect of showing the effect of angle-dependent color variation is more obvious; the angle-sensitive properties of the optical pigment can thus be adjusted by adjusting the thickness of the first dielectric layer 11, resulting in an optical pigment with a desired degree of flop effect.

Example 5:

400ml of deionized water is added into a 1L reaction kettle, and 15g of flaky titanium powder is added, wherein the thickness of titanium flakes is 0.25um, the average particle size is 60 mu m, and the mixture is stirred and heated to 75 ℃; the pH is adjusted to 8.1 by using dilute hydrochloric acid with the mass fraction of 5% and NaOH solution with the mass fraction of 10%; 40ml of Na with mass fraction of 20% is added dropwise in a metering manner ₂ SiO ₃ ·9H ₂ O solution is added dropwise with 5 percent of dilute hydrochloric acid to maintain constant pH, and after the addition is completed, the mixture is stirred for 30 minutes at constant temperature to form SiO on the outer surface of the titanium sheet ₂ The layers were filtered and rinsed 3 times with water to give a first filtered product, wherein SiO ₂ The thickness of the layer was about 20nm.

The first filtered product was added to 400ml deionized water, stirred and added to 75 ℃. The pH of the suspension was adjusted to 3.3 using 5% by mass of dilute hydrochloric acid and 10% by mass of NaOH solution, and 300ml of FeCl with a concentration of 60g/L was metered in ₃ The solution was simultaneously added dropwise with 25% by mass of NaOH solution to maintain the pH constant, and after the addition was completed, stirred at constant temperature for 30 minutes to obtain a solution containing Al ₂ O ₃ Forming Fe on the outer surface of the layer ₂ O ₃ The layers were filtered and rinsed 3 times with water to finally obtain a second filtered product, wherein TiO ₂ The thickness of the layer was about 150nm.

The final second filtered product was dried in an oven at 120 ℃ and calcined at 800 ℃ for 1h to give an orange pigment.

Comparative example 1 and example 5: the second dielectric layer 12 of the optical pigment obtained in example 1 is TiO ₂ A layer, eventually yielding a blue pigment; the second dielectric layer 12 of the optical pigment obtained in example 5 is Fe ₂ O ₃ A layer, eventually resulting in an orange pigment; it is easy to see that, under the same conditions, the color of the optical pigment, that is, the second dielectric layer 12 of different materials, can be changed by changing the material of the second dielectric layer 12, and the color of the obtained optical pigment is different correspondingly, and it is clear that, in combination with comparative example 1 and example 2, the desired color can be obtained by adjusting the thickness of the second dielectric layer 12 and/or selecting the second dielectric layer 12 of different materials.

The foregoing is only the embodiments of the present application, and therefore, the patent scope of the application is not limited thereto, and all equivalent structures or equivalent processes using the descriptions of the present application and the accompanying drawings, or direct or indirect application in other related technical fields, are included in the scope of the application.

Claims (10)

1. An optical pigment, comprising:

an opaque substrate;

the first dielectric layer is coated on the surface of the opaque substrate;

the second medium layer is coated on the surface of the first medium layer, and the refractive index of the first medium layer is smaller than that of the second medium layer.

2. The optical pigment of claim 1, wherein the first dielectric layer covers the entire outer surface of the opaque substrate; the second dielectric layer covers the whole outer surface of the first dielectric layer.

3. The optical pigment of claim 1, wherein the refractive index of the first dielectric layer is less than a threshold value and the refractive index of the second dielectric layer is greater than the threshold value; wherein the threshold value is in the range of 1.1-2.8.

4. The optical pigment of claim 1, wherein the first dielectric layer has a thickness of 5-1000nm and the second dielectric layer has a thickness of 5-1000nm.

5. The optical pigment according to claim 1, wherein the opaque substrate has an average particle diameter of 10 to 100 μm and an average thickness of 0.1 to 5 μm.

6. The optical pigment of claim 1, wherein the opaque substrate is one or more of graphite flakes, aluminum flakes, silver flakes, gold flakes, titanium flakes, nickel flakes, iron flakes, copper flakes, tin flakes, or alloys thereof.

7. The optical pigment according to claim 1, wherein the first dielectric layer is one or more of silica, aluminum oxide, boron trioxide, magnesium oxide, magnesium fluoride, yttrium trioxide, and silicon monoxide;

the second dielectric layer is made of one or more of titanium dioxide, tin dioxide, ferric oxide, cuprous oxide, ferric oxide, molybdenum oxide, tungsten oxide, zinc oxide, zirconium oxide and tantalum pentoxide.

8. A method of preparing an optical pigment comprising:

adding an opaque substrate into deionized water according to the mass ratio of 3% -10%, stirring and heating to 60-90 ℃, regulating the pH value to 4-9, metering soluble inorganic salt corresponding to a first medium material, stirring for a first preset time, filtering and flushing to obtain a first filtering product, so as to form a first medium layer on the surface of the opaque substrate;

adding the first filtering product into deionized water according to the mass ratio of 3% -15%, stirring and heating to 60-90 ℃, regulating the pH value to 1-4, metering the soluble inorganic salt corresponding to the second medium material, stirring for a second preset time, filtering and flushing to obtain a second filtering product, so as to form a second medium layer on the surface of the first medium layer; wherein the refractive index of the first dielectric material is smaller than the refractive index of the second dielectric material.

9. The method of preparing an optical pigment according to claim 8, further comprising:

calcining the second filtered product at a temperature of not less than 600 ℃.

10. The method of producing an optical pigment according to claim 8, wherein the opaque substrate is one or more of graphite flakes, aluminum flakes, silver flakes, gold flakes, titanium flakes, nickel flakes, iron flakes, copper flakes, tin flakes, or an alloy thereof;

the first dielectric material is one or more of silicon dioxide, aluminum oxide, boron oxide, magnesium fluoride, yttrium oxide and silicon monoxide;

the second dielectric material is one or more of titanium dioxide, tin dioxide, ferric oxide, cuprous oxide, ferric oxide, molybdenum oxide, tungsten oxide, zinc oxide, zirconium oxide and tantalum pentoxide.