A high near-infrared reflecting compound, and a preparation method and application thereof

Abstract

The application belongs to the field of near-infrared radiation coatings, and particularly relates to a high near-infrared reflection compound, a preparation method and application thereof. 1‑x‑ y Mn y Fe x O3, wherein 0.4<=x<=0.5, 0.1<=y<=0.5, when the x<=0.3, the YIn 1‑x‑y Mn y Fe x O3 is a crystal structure, the crystal belongs to a hexagonal system, a space group is P63cm (185), a unit cell parameter is alpha=beta=90 degrees, gamma=120 degrees, Z=6, and the application can change the color of the pigment by changing the element content of iron and manganese, and has high near-infrared reflectivity.

Description

Technical Field

[0001] This invention belongs to the field of near-infrared radiation coatings, and particularly relates to a high near-infrared reflectance compound, its preparation method, and its application. Background Technology

[0002] The massive trend of urbanization has led to rapid changes in urban climate. Due to factors such as large amounts of artificial waste heat, high-temperature heat storage bodies like buildings and roads, and the reduction of green spaces, urban temperatures are higher than suburban temperatures. When atmospheric circulation is weak, hot air rises in the city and sinks in the suburbs. This sinking air then flows from near the ground back towards the city center, carrying pollutants emitted by suburban factories into the city, forming an urban heat island circulation between the city and suburbs. Improving energy efficiency, using building insulation materials, and developing personal thermal management technologies can mitigate the impact of the urban heat island.

[0003] Solar radiation includes ultraviolet radiation, visible light radiation, and infrared radiation, which account for 5%, 43%, and 52% of solar radiation, respectively. It is reported that about 60% of solar radiation can be absorbed by building surfaces and transmitted to the interior of buildings through roofs and walls, resulting in heat accumulation, increased temperature, and increased energy consumption for air conditioning in summer.

[0004] Some studies have shown that solar reflective coatings can replace traditional coatings, reflecting most solar radiation, especially the high-heat solar radiation in the near-infrared (NIR) region, thus reducing indoor heat accumulation. It is understood that white pigments such as titanium dioxide have a near-infrared reflectance of over 90%, while black pigments such as carbon black have almost 0%. Although dark pigments have lower solar reflectance, dark tones remain important decorative colors, favored for their aesthetics and practicality. In practical applications, dark pigments with high near-infrared reflectance can replace traditional dark pigments to obtain coatings with similar colors but higher reflectance.

[0005] Currently, there are some studies and reports on black pigments with high near-infrared reflectance. Oka and Masui synthesized Ti-doped pigments using a solid-state synthesis method. 4+ Ca2MnO4 black pigment, Ti 4+ Doping changes the sample's hue from black to dark brown. When Ti... 4+When the doping concentration reaches 0.15%, the obtained pigment not only has good black chromaticity (L* = 23.8, a* = 4.45, b* = 2.83), but also good near-infrared reflectance (R* = 66.2%). Sangwong et al. synthesized a black pigment with high near-infrared reflectance, CoFe2O4. When the molar ratio of alumina and dolomite was 0.5 and 0.25, respectively, the near-infrared reflectance of the pigment increased from 17.5% without doping to 22.5% and 24.5%. Bao et al. prepared a pigment with the general formula Co using the sol-gel method. 0.5 Mg 0.5 Al 2-x Fe x O4 pigments, Fe 3+ Doping changes the hue of the sample from blue to black. The near-infrared reflectance R* of the black pigment (0.8≤x≤1.0) is 43.0-45.7%, with the specific reflectance depending on the amount of iron doping. Bai et al. also introduced a near-infrared reflective black pigment CuCr based on Fe / Mn co-doping. 2-x-y Fe x Mn y O4, depending on the Fe / Mn doping concentration, exhibits brightness values ​​(L*) ranging from 17.72 to 21.21, with the highest near-infrared reflectance (R*) reaching 27.7%; Moriomoto et al. reported a novel black pigment, Ce. 1-x Gd x VO4 (0.2≤x≤0.3) has a luminance value L* ranging from 22.2 to 23.2 and a near-infrared reflectance R* ranging from 66.3 to 67.0%.

[0006] Smith et al. prepared a blue pigment YIn with a trigonal bipyramidal (TBP) hexagonal monolayer crystal structure. 1-x Mn x O3, when Mn is introduced 3+ Replaces In with different amounts 3+ When, YIn 1-x Mn x O3 exhibits a range of color variations from blue to black; samples of different colors can be synthesized by replacing the trigonal bipyramidal positions in the YInO3 (white) crystal structure. 3+ Doping with Mn typically darkens the matrix hue; however, during Mn doping... 3+ Or Fe 3+ When doping with YInO3, the cost of the reaction raw materials is high, and the synthesis temperature is also high, making it difficult to use on a large scale. Summary of the Invention

[0007] To address the shortcomings of existing technologies, this invention provides a high near-infrared reflectance compound, its preparation method, and its applications. The compound has the general formula YIn.1-x-y Mn y Fe x O3 (0.4≤x≤0.5, 0.1≤y≤0.5) can change the color of pigments by altering the content of iron and manganese, and it also has a high near-infrared reflectivity.

[0008] In a first aspect, the present invention provides a high near-infrared reflectance compound with the chemical formula YIn. 1-x-y Mn y Fe x O3, where 0.4≤x≤0.5, 0.1≤y≤0.5.

[0009] According to an embodiment of the present invention, when x ≤ 0.3, the YIn 1-x-y Mn y Fe x O3 has a crystal structure, belonging to the hexagonal crystal system, with space group P63cm(185) and unit cell parameters of... α=β=90°, γ=120°, Z=6,

[0010] According to an embodiment of the present invention, when 0.4 ≤ x ≤ 0.5, the YIn 1-x-y Mn y Fe x O3 is a solid solution.

[0011] According to an embodiment of the present invention, the YIn 1-x-y Mn y Fe x O3 is particulate matter, such as the Yin mentioned above. 0.6- y Mn y Fe 0.4 The size of O3 particles ranges from 1 to 50 μm.

[0012] According to an embodiment of the present invention, the YIn 1-x-y Mn y Fe x The luminance value L* of O3 is 23.27 to 32.12.

[0013] According to an embodiment of the present invention, the YIn 1-x-y Mn y Fe x The minimum saturation of O3 is 0.09.

[0014] According to an embodiment of the present invention, when 0.4 ≤ y ≤ 0.5, the YIn 1-x-y Mn y Fe x O3 is a black particulate matter.

[0015] According to an embodiment of the present invention, when 0.4 ≤ x ≤ 0.5, the YIn 1-x-y Mn y Fe x O3 is a black particulate matter.

[0016] According to an embodiment of the present invention, the YIn 1-x-y Mn y Fe x O3 has a near-infrared solar reflectance greater than 30%, preferably YIn. 1-x-y Mn y Fe x O3 has a near-infrared solar reflectance greater than 35%, and more preferably YIn 1-x-y Mn y Fe x O3 has a near-infrared solar reflectance greater than 40%, for example, 35%, 40%, 45%, 50%, 52%, and 53%.

[0017] According to an embodiment of the present invention, the YIn 1-x-y Mn y Fe x O3 has a reflectivity greater than 30% at 1100 nm, and YIn is preferred. 1-x-y Mn y Fe x O3 has a reflectivity greater than 35% at 1100 nm, for example, 40%, 45%, 50%, and 53%.

[0018] According to an embodiment of the present invention, the YIn 1-x-y Mn y Fe x O3 exhibits good stability in 5% H2SO4, HNO3, HCl, NaOH, or deionized water, with a total color difference ΔE* ≤ 2 after 24 hours of soaking, preferably ΔE* ≤ 1.5.

[0019] According to an embodiment of the present invention, the YIn 1-x-y Mn y Fe x O3 has heat insulation properties, and YIn is coated with it under infrared irradiation. 1-x-y Mn y Fe x The temperature difference between O3 and iron black pigment on metal surfaces can reach 20°C.

[0020] According to an embodiment of the present invention, the YIn 1-x-y Mn y Fe x O3 has basic properties such as Figure 1The XRD diffraction pattern shown.

[0021] According to an embodiment of the present invention, the YIn 1-x-y Mn y Fe x O3 has basic properties such as Figure 2 The SEM image shown.

[0022] According to an embodiment of the present invention, the YIn 0.9-x Mn 0.1 Fe x O3 has basic properties such as Figure 4 The UV-Vis diffuse reflectance spectrum is shown.

[0023] According to an embodiment of the present invention, the YIn 0.6-y Mn y Fe 0.4 O3, YIn 0.5-y Mn y Fe 0.5 O3 has basic properties such as Figure 5 The UV-Vis diffuse reflectance spectrum is shown.

[0024] According to an embodiment of the present invention, the YIn 0.6-y Mn y Fe 0.4 O3, YIn 0.5-y Mn y Fe 0.5 O3 has basic properties such as Figure 8 The near-infrared reflectance map and the near-infrared solar reflectance map are shown.

[0025] Secondly, the present invention also provides the above-mentioned compound YIn 1-x-y Mn y Fe x Methods for preparing O3 include those using methods known in the art, such as sol-gel methods, hydrothermal methods, co-precipitation methods, and solid-phase synthesis methods, for example, using YIn 1-y Mn y YIn was prepared via solid-state synthesis using O3 as the matrix and iron oxide as the iron source. 1-x-y Mn y Fe x O3.

[0026] According to an embodiment of the present invention, the solid-state synthesis of compound YIn 1-x-y Mn y Fe x O3 includes the following steps:

[0027] S1. Mix and dry the iron source, manganese source and yttrium source;

[0028] S2. React the dried mixture at a temperature of 600–1300℃ for 200–400 min.

[0029] According to an embodiment of the present invention, the iron source, manganese source, and yttrium source are selected from at least one of the corresponding carbonates, nitrates, chlorides, and oxides, preferably the corresponding oxides, such as iron oxide, manganese oxide, and yttrium oxide.

[0030] According to an embodiment of the present invention, the molar ratio of the iron source, manganese source and yttrium source is (1-5):(1-5):10.

[0031] According to an embodiment of the present invention, step S1 includes the following steps: adding an iron source, a manganese source, and a yttrium source to a solvent for grinding, and then drying.

[0032] According to an embodiment of the present invention, the solvent is selected from volatile solvents ethanol and / or acetone, for example, acetone.

[0033] According to an embodiment of the present invention, the grinding includes grinding until the solvent evaporates, repeating several times. For example, an iron source, a manganese source, and a yttrium source are added to acetone and ground until the acetone evaporates, then acetone is added again and ground until it evaporates, repeating this process 3-4 times.

[0034] According to an embodiment of the invention, the drying includes drying at a temperature of 40–70°C for 50–120 min, for example, drying in an oven at 60°C for 100 min. According to an embodiment of the invention, the reaction in step S2 includes first heating the dried mixture to 600–1000°C and holding it at that temperature for 100–150 min, and then heating it to 1100–1300°C and holding it at that temperature for 100–150 min.

[0035] According to an embodiment of the present invention, after step S2, the following steps are further included: cooling the reaction product to room temperature and grinding it, for example, cooling the reaction product to room temperature and then wet grinding it 2 to 5 times.

[0036] Thirdly, the present invention also provides the above-mentioned compound YIn 1-x-y Mn y Fe x The application of O3 in near-infrared reflection is preferably in vehicles, building walls, etc.

[0037] Fourthly, the present invention also provides a near-infrared reflective pigment, the pigment comprising the compound YIn as described above. 1-x-y Mn y Fe x O3.

[0038] According to an embodiment of the present invention, the pigment is black, and preferably the pigment further includes a dispersion solution selected from those capable of dispersing YIn1-x-y Mn y Fe x A liquid in which O3 is uniformly dispersed.

[0039] Fifthly, the present invention also provides a near-infrared reflective coating, the coating comprising the compound YIn as described above. 1-x-y Mn y Fe x O3.

[0040] According to an embodiment of the present invention, the coating is black.

[0041] According to an embodiment of the present invention, the coating further includes a solvent selected from resins, oils and / or emulsions.

[0042] According to an embodiment of the present invention, the coating further includes auxiliary materials selected from at least one of dispersing agents, binders, film-forming agents, preservatives, leveling agents, and dispersants.

[0043] According to an embodiment of the present invention, the near-infrared reflective coating comprises the compound YIn 1-x-y Mn y Fe x O3 and existing coatings, such as the near-infrared reflective coating, include the compound YIn. 1-x-y Mn y Fe x O3, alkyd resin and / or protective coating.

[0044] Beneficial effects

[0045] (1) The compound YIn of the present invention 1-x-y Mn y Fe x O3 has good black chromaticity, with an L* value between 23.27 and 32.12 and a minimum saturation C* of 0.09. It also has good near-infrared reflectance properties, with a maximum near-infrared solar reflectance R* of 53.44%. Therefore, it can be used as a cool-color pigment in the fields of architecture, automobiles and ceramics.

[0046] (2) The compound YIn prepared in this invention 1-x-y Mn y Fe x The O3 method is relatively simple, and the raw materials are readily available and the cost is low. Attached Figure Description

[0047] Figure 1 YIn prepared in Example 1 of this invention 0.9-x Mn 0.1 Fe x XRD diffraction pattern and magnified view of O3 pigment powder;

[0048] Figure 2 For YIn in this test case 1 0.6-y Mn y Fe 0.4 XRD pattern of O3 (y = 0.1-0.5) pigment powder;

[0049] Figure 3 For YIn in this test case 2 0.6-y Mn y Fe 0.4 SEM images of O3 (y = 0.1-0.5) pigment powder;

[0050] Figure 4 (a) YIn in test example 1 0.6-y Mn y Fe 0.4 Particle size distribution diagram of O3 pigment; Figure 4 (b) YIn in Test Example 1 0.5-y Mn y Fe 0.5 Particle size distribution diagram of O3 pigment;

[0051] Figure 5 For YIn in test example 3 0.9-x Mn 0.1 Fe x UV-Vis diffuse reflectance spectra of O3 (x = 0-0.5) pigment samples;

[0052] Figure 6 The above shows YIn corresponding to different y values ​​in test example 3. 0.6-y Mn y Fe 0.4 The ultraviolet-visible diffuse reflectance spectrum of O3 pigment powder; Figure 6 Below is the YIn corresponding to different y values ​​in Test Example 3. 0.5-y Mn y Fe 0.5 The ultraviolet-visible diffuse reflectance spectrum of O3 pigment powder;

[0053] Figure 7 For test example 4, the different x and y values ​​corresponding to YIn 1-x-y Mn y Fe x Chromaticity coordinate diagram of O3 (x = 0.4-0.5, y = 0.1-0.5) pigment;

[0054] Figure 8 For test example 4, the different x values ​​correspond to YIn 0.9-x Mn 0.1 Fe x A physical image of an O3 pigment sample;

[0055] Figure 9 (a) YIn in test example 5 0.6-y Mn y Fe 0.4 Near-infrared reflectance diagram of O3 pigment; Figure 9 (b) YIn in test example 5 0.5-y Mn y Fe 0.5 Near-infrared reflectance diagram of O3 pigment; Figure 9 (c) YIn in test example 5 0.6-y Mn y Fe 0.4 Near-infrared solar reflectance of O3 pigment; Figure 9 (d) is YIn in test example 5 0.5-y Mn y Fe 0.5 Near-infrared solar reflectance of O3 pigment;

[0056] Figure 10 For example 6, YIn was coated 0.5 Mn 0.1 Fe 0.4 Actual image of the interior air temperature test of a car model using O3 pigment (T1) and commercial iron black pigment (T2). Detailed Implementation

[0057] The compounds, their preparation methods, and applications of the present invention will be further described in detail below with reference to specific embodiments. It should be understood that the following embodiments are merely illustrative and explanatory of the present invention and should not be construed as limiting the scope of protection of the present invention. All technologies implemented based on the above content of the present invention are covered within the scope of protection intended by the present invention.

[0058] Unless otherwise stated, the raw materials and reagents used in the following examples are commercially available products or can be prepared by known methods.

[0059] reagents

[0060] The reagents Y2O3 and In2O3 used in the following examples were obtained from Energy Chemical (Shanghai) Co., Ltd., MnO2 was provided by Shanghai Maclean Biochemical Co., Ltd., and Fe2O3 was purchased from Aladdin Reagent (Shanghai) Co., Ltd. The purity of the above oxides is all above 99%.

[0061] Test and characterization methods

[0062] The pigments synthesized in the following examples were tested and characterized using the following instruments and methods:

[0063] The crystal and phase information of the synthesized sample was measured using a Rigaku MiniFlex 600 X-ray diffractometer (CuK-α radiation). The test conditions included 40 kV and 15 mA, a scanning speed of 8° / θ, a scanning step size of 0.02, and a scanning range of 10–80°. Diffraction spectrum data were obtained.

[0064] The morphology, structure, and elemental distribution of the pigment powder samples were analyzed using Apreo S LoVac field emission scanning electron microscopy (FESEM) and energy-dispersive X-ray spectroscopy (EDS).

[0065] The particle size distribution of the sample was detected using a Brookaven Omni particle size analyzer. The test method included immersing a small amount of pigment sample in anhydrous ethanol, dispersing it ultrasonically, and then adding it to the particle size analyzer for testing.

[0066] The absorption and reflectance spectra of the samples were determined using an Agilent Carry 5000 UV-Vis-NIR spectrophotometer. The test method included: placing an appropriate amount of sample into a sample container and flattening it; using BaSO4 as a baseline standard; measuring the reflectance of the pigment powder in the wavelength range of 200–2500 nm; and determining the average reflectance R of the pigment sample in the range of 700–2500 nm. The near-infrared reflectance R* of the sample was calculated using equation (1):

[0067]

[0068] In equation (1), r(λ) represents the experimentally measured spectral reflectance, and i(λ) represents the solar spectral irradiance according to the ASTM (American Society for Testing and Materials) standard.

[0069] The band gap is defined by equation (2):

[0070]

[0071] In equation (2), λ represents the absorption edge of the ultraviolet-visible (UV-VIS) spectral region.

[0072] Based on the average reflectance R of the pigment sample in the UV-Vis region, the band gap energy F(R) is calculated using the Kubelka-Munk formula (Formula 3):

[0073]

[0074] With (F(R)) 2 E is the ordinate. g Plot the curve on the x-axis; the intersection of the tangent line to the x-axis represents the absorption limit of the sample.

[0075] Colorimetric tests were performed using a CS-580A (Hangzhou CHN Spec) spectrophotometer under D65 standard light source and a 10° observation angle. The chromaticity coordinates of the pigment samples were described using the CIEL*a*b* (1976) color space system. In this system, L* ranges from 0 to 100, representing the change in brightness from black to white. The values ​​of A* and b* represent the red (+)-green (-) and yellow (+)-blue (-) attributes of the pigment samples, respectively, with values ​​ranging from -128 to +128. The value of C* represents the color saturation of the sample, calculated as shown in Formula 4.

[0076]

[0077] Example 1: YIn was prepared by solid-state synthesis. 1-x-y Mn y Fe x O3 is a black pigment.

[0078] S1. Mix Y2O3, In2O3, Fe2O3 and MnO2 according to the mass shown in Table 1. Put the mixture into agate mortar and wet grind it with 1-2 mL of acetone. Grind the mixture in the presence of acetone until the acetone evaporates. Repeat the grinding 3-4 times to obtain the ground mixture.

[0079] Table 1 Reactants in different proportions

[0080]

[0081] S2. Dry the ground mixture in an oven at 60°C for 100 minutes to obtain a dried sample.

[0082] S3. Place the dried sample into a corundum crucible and place it in a muffle furnace for solid-phase synthesis: first heat to 800℃ at a heating rate of 10℃ / min and hold for 120 minutes, then heat to 1150℃ at a heating rate of 10℃ / min and hold for 120 minutes, then cool to room temperature to obtain the calcined product.

[0083] S4. Add 1-2 mL of acetone to the calcined product and wet-mill 3-4 times to obtain the pigment sample.

[0084] Test Example 1 Phase Analysis

[0085] See Figure 1 As shown, this represents the YIn synthesized in Example 1 after calcination at 1150℃ for 2 hours, with y = 0.1, and corresponding values ​​for y = 0.1, 0.2, 0.3, 0.4, and 0.5. 0.9-x Mn 0.1 Fex The X-ray diffraction pattern of the O3 pigment sample shows that the main diffraction peak is sharp and high, indicating that the sample has good crystallinity.

[0086] Low Fe 3+ The X-ray diffraction pattern of the doped sample (x≤0.3) is consistent with that of the standard card PFD70-0133 (YInO3), indicating low Fe content. 3+ The doped sample belongs to the hexagonal crystal system, space group P63cm(185), and unit cell parameters are... α=β=90°, γ=120°, Z=6,

[0087] With Fe 3+ With increasing doping concentration, the intensity of the main diffraction peak of YInO3 gradually decreased, and a main diffraction peak reflecting the phase transition (x≥0.4) appeared. The decrease in the intensity of the main diffraction peak indicates a decrease in the crystallinity of the sample, which mainly depends on the change in the radius of the metal ions before and after doping. At the same time, with increasing doping concentration, the (221) and (222) crystal planes shifted to higher angles in the range of 2θ=58.8~62.4°. According to Bragg's law: 2dsinθ=nλ, when the iron ion with a smaller radius ( ) Replaces In with a larger radius 3+ ( When the crystal lattice contracts to a certain extent and the crystal planes shift at large angles, it indicates that the solid solution has been successfully formed. The absence of major diffraction peaks for Y₂O₃, Fe₂O₃, In₂O₃, and MnO₂ in the X-ray diffraction pattern further confirms that the raw material has completely formed YIn. 0.9-x Mn 0.1 Fe x O3 solid solution.

[0088] YIn 0.5-y Mn y Fe 0.5 The X-ray diffraction pattern of the O3 (y = 0.1–0.5) sample is as follows: Figure 2 As shown, with the increase of manganese content, the main phase of the sample changes from the coexistence of YInO3 and YFeO3 phases to the YFeO3 phase. In addition, a small number of unreacted Y2O3 diffraction peaks exist in the range of y = 0.3 to 0.5.

[0089] Test Example 2 Morphology Analysis

[0090] YIn prepared in Example 1 was observed using a field emission scanning electron microscope. 0.6-y- Mn y Fe 0.4 The morphological characteristics of O3 (y = 0.1-0.5) black pigment, such as Figure 3As shown, all pigment samples corresponding to different y values ​​have similar and irregular morphologies. Samples with different y values ​​all contain large particles, that is, there is a certain degree of agglomeration. The size of the agglomerated particles is 1-50 μm. As the y value increases, the amount of small particles gradually increases. This may be related to the grinding method and the quenching, heat treatment and time of the synthesis method.

[0091] In subsequent coating processes, the uniformity of pigment particles plays a crucial role in the smoothness of the coating. (See...) Figure 4 As shown, YIn 0.6-y Mn y Fe 0.4 O3 and YIn 0.5-y Mn y Fe 0.5 The average particle size (D50) of the O3 (y = 0.1, 0.2, 0.3, 0.4, 0.5) pigment samples was less than 3 μm, among which YIn 0.5 Mn 0.1 Fe 0.4 O3 pigment particles are the smallest and most evenly distributed. The D10, D50 and D90 data of different samples are shown in Table 2. Under the premise of constant iron content, the D50 of the samples increases with the increase of manganese content.

[0092] Table 2 YIn 1-x-y Mn y Fe x O3 (x = 0.4-0.5, y = 0.1-0.5) black pigment powder, D10, D50, D90

[0093]

[0094] Test Example 3: UV-Vis Diffuse Reflectance Analysis

[0095] To understand the absorption characteristics of different pigment samples in the 200-800 nm (UV-Vis) wavelength range, YIn was measured. 0.9-x Mn 0.1 Fe x The diffuse reflectance spectra of O3 samples (x = 0, 0.1, 0.2, 0.3, 0.4, 0.5), such as... Figure 5 As shown, the sample has two main absorption peaks near 2 eV and 3.5-6.2 eV, respectively. With the increase of Fe... 3+ With increasing doping concentration, the weak absorption peak at 2.5-3 eV increases, and the low-energy absorption peak near 2 eV broadens. When x ≥ 0.4, the sample absorbs almost all visible light, and the corresponding pigment gradually changes from blue to black. The change in pigment color can be attributed to the sub-bandgap energy level caused by a large number of surface and interface defects in the aggregated particles.

[0096] The results show that the generation of the low-energy absorption peak is related to Mn 3+ e′(d x 2 -y 2 d xy ) to a′(D z 2 The absorption peak is related to the transition, with slight fluctuations around 2.2 eV, mainly depending on the 3d phase transition. xz up to 3 dz 2 The weak bandgap transition from O 2p to Mn 3d z 2 Charge transfer in YIn leads to the formation of high-energy absorption peaks (3.5-6.2 eV) in the sample. 0.9-x Mn 0.1 Fe x The high-energy absorption peaks of the O3 samples (x = 0, 0.1, 0.2, 0.3, 0.4, 0.5) are similar.

[0097] Figure 6 Showing YIn 1-x-y Mn y Fe x UV-Vis diffuse reflectance spectra of O3 (x = 0.4, 0.5, y = 0.1, 0.1, 0.2, 0.3, 0.4, 0.5) black pigment samples. The results show that with the increase of manganese content, the absorption peak in the visible light region of the black samples tends to be flat, and the high-energy absorption peak (3.5-6.2 eV) decreases.

[0098] Test Example 4: Study on Color Properties

[0099] The color properties of synthetic pigments are defined by the CIE L*a*b* (1976) color space system. See also Figure 7 and Figure 8 As shown, YIn 1-x-y Mn y Fe x The chromaticity parameters of the O3 (x / y = 0.1, 0.1, 0.2, 0.3, 0.4, 0.5) series pigments are given. When x = 0 and y = 0.1, the sample is undoped with Fe. 3+ At the initial concentration, the sample exhibited a bright blue color, with the highest blue hue (b* = -45.91) and brightness value (L* = 44.13). As the x content increased (y = 0.1), the sample color gradually changed from bright blue to dark blue, and finally to black.

[0100] See Figure 7 As shown, with the manganese content remaining constant, it can be observed that as the Fe content increases... 3+Increasing the doping concentration leads to a decrease in the L* value and an increase in the b* value, indicating a reduction in both the brightness and blue hue of the sample. As the y content increases, the range of L* and b* values ​​gradually decreases with increasing x, while the a* and b* values ​​approach 0, suggesting that increasing the manganese content also darkens the pigment sample color. When Fe... 3+ When the doping amount is 0.4 (x≥0.4), the sample appears black.

[0101] The chromaticity parameters of the black pigment are shown in Table 3. The L* value of the black pigment ranges from 23.27 to 32.12, and the minimum saturation C* is 0.09 (x = 0.5, y = 0.2). 3+ or Fe 3+ An increase in content will cause the sample to darken in color.

[0102] Table 3 YIn 1-x-y Mn y Fe x Chromaticity coordinates and band gap of O3 pigment (x = 0.4-0.5, y = 0.1-0.5)

[0103]

[0104] Test Example 5: Near-infrared reflectance study

[0105] The reflectivity of synthetic pigments can reflect their heat insulation capabilities. Near-infrared reflectance of the samples was measured in the wavelength range of 700-2500 nm. (See [reference needed]). Figure 9 From a and 9b, we can see that Mn 3+ and Fe 3+ The doping of YIn has a significant effect on the near-infrared reflectance of black pigments. 1-x-y Mn y Fe x The near-infrared reflectance of O3 samples (x = 0.4, 0.5, y = 0.1, 0.2, 0.3, 0.4, 0.5) varies with Fe. 3+ or Mn 3+ The doping concentration gradually decreases with increasing doping concentration, which may be related to the increase in free carrier concentration.

[0106] The reflectance and average reflectance (R%) of the black pigment at 1100 nm are shown in Table 4. The near-infrared reflectance of the sample is highest when x = 0.4 and y = 0.1. The near-infrared solar reflectance curve calculated according to ASTM standard G173-03 is shown in Table 4. Figure 9 As shown in c and 9d, the maximum value of the near-infrared solar reflectance (R*) can reach 53.44% (x = 0.4, y = 0.1), indicating that the synthesized black pigment has significantly better reflective properties than commercial black pigment.

[0107] Table 5 shows a comparison between the synthesized black pigment and other black pigments. The results indicate that the synthesized YIn 1-x- y Mn y Fe x O3 black pigments have high near-infrared reflectance at similar chromaticity coordinates, making them potential candidates for use as cool-toned pigments in the construction, automotive, and ceramics industries.

[0108] Table 4. Near-infrared reflectance and near-infrared solar reflectance values ​​of black pigment samples.

[0109]

[0110] Table 5. Comparison of L*a*b* coordinates and near-infrared reflectance of the synthetic pigment with other black pigment samples.

[0111]

[0112]

[0113] Test Example 6: Thermal Insulation Performance Study

[0114] The study of the thermal insulation properties of synthetic pigments can more intuitively reflect their reflectivity in practical applications. This test example uses YIn prepared in Example 1. 0.5 Mn 0.1 Fe 0.4 O3 and commercially available iron black pigment powder were mixed with alkyd resin at a 1:1 mass ratio and evenly coated onto a 15*8.5*9.5cm iron car model. The model was then air-dried. The top of the model was kept 15cm vertically from a 100W infrared lamp, and the location and temperature of the highest point on the coating were observed using an infrared thermal imager. The air temperature inside the car was measured using a UT320D thermocouple thermometer. The coated model was then placed under the infrared lamp for 90 minutes under ventilated conditions, and the air temperature inside the car model was measured using a thermocouple thermometer. The air temperature inside the model was recorded at 2, 4, 6, 8, 10, 30, 60, and 90 minutes. During the irradiation process, the car windows were opened to ensure ventilation between the car body and the outside air, preventing heat buildup inside.

[0115] See Figure 10 It can be seen that it is coated with YIn 0.5 Mn 0.1 Fe 0.4 The internal air temperature of the iron car model with O3 pigment and iron black pigment rose rapidly within 10 minutes, and then gradually slowed down as the irradiation time increased. Finally, the internal air temperature difference between the two stabilized at 7℃ (ΔT=T2-T1).

[0116] Meanwhile, the surface temperature of the car model was observed using an infrared thermal imager. The results showed that the highest temperature was consistently found on the roof coated with iron black pigment. After 90 minutes of infrared irradiation, the temperature difference on the roof could reach 20°C. This phenomenon is attributed to the high near-infrared absorption rate of commercial iron black pigment, leading to significant heat accumulation. The synthesized pigment can reflect more near-infrared radiation, reducing the indoor temperature and thus lowering energy consumption. In summary, the YIn synthesized in this invention… 0.5 Mn 0.1 Fe 0.4 O3 pigments have better heat insulation properties than commercial black pigments in practical applications.

[0117] Test Example 7 Chemical Stability Study

[0118] The chemical stability of pigments is an important indicator of their durability in practical applications. To evaluate the chemical stability of synthetic pigments, equal masses of YIn were taken... 0.5 Mn 0.1 Fe 0.4 O3 pigment was soaked in 5% H2SO4, HNO3, HCl, NaOH, and deionized water solutions for 24 hours, respectively. The soaking solutions were then filtered, washed, and dried. The chromaticity coordinates of the soaked pigment powder were measured and compared with those of the original pigment.

[0119] Referring to Table 6, the color coordinate difference and total color difference (ΔE*) of the synthesized pigment powder before and after soaking are shown. When ΔE* ≤ 5, it can be considered that the pigment powder can still maintain its original color after soaking in acid and alkaline solutions. In this invention, ΔE* ≤ 2 for all samples, indicating that the color of the samples prepared in this invention hardly changes after soaking in acid and alkaline solutions, confirming the effectiveness of the synthesized YIn in this invention. 0.5 Mn 0.1 Fe 0.4 O3 pigments have good chemical stability.

[0120] Table 6. L*a*b*chromaticity coordinate difference and total color difference of pigment powder

[0121]

[0122] The specific embodiments of the present invention have been described above by way of example. However, the scope of protection of the present invention is not limited to the above exemplary embodiments. Any modifications, equivalent substitutions, improvements, etc., made by those skilled in the art within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A method of preparing a high near infrared reflecting compound, characterized by, The chemical formula of the compound is YIn 1-x- y Mn y Fe x O3, wherein x = 0.4 or 0.5, y = 0.1, 0.2, 0.3; Preparation of compound YIn 1-x-y Mn y Fe x O3 includes the following steps: S1, grinding Y2O3, In2O3, MnO2, Fe2O3 with solvent, and then drying; S2, reacting the dry mixture at a temperature of 600-1300℃ for 200-400min.

2. The method of preparing a high near infrared reflecting compound according to claim 1, wherein, The YIn 1-x- y Mn y Fe x The brightness value L* of the YIn 1-x-y Mn y Fe x The minimum saturation C* of the YIn 3. The method of making a high near-infrared reflecting compound according to claim 1, wherein, The YIn 1-x- y Mn y Fe x O3 is particulate matter.

4. The method of making a high near-infrared reflecting compound according to claim 1, wherein, The YIn 1-x- y Mn y Fe x O3 has a reflectivity greater than 30% at 1100 nm.

5. The method of making a high near-infrared reflecting compound according to any one of claims 1-4, wherein, The reaction in step S2 includes first heating the dry mixture to 600-1000℃ and keeping the temperature for 100-150min, and then heating to 1100-1300℃ and keeping the temperature for 100-150min.

6. The method of making a high near-infrared reflecting compound according to any one of claims 1-4, wherein, After step S2, the following step is included: wet grinding the reaction product for 2-5 times after cooling to room temperature.

7. A compound YIn prepared by the process of any one of claims 1-6. 1-x-y Mn y Fe x O3 in near infrared reflection.

8. A near infrared reflecting pigment, characterized in that, The pigments comprise the compound YIn prepared according to the preparation method of any one of claims 1 to 6 1-x-y Mn y Fe x O3.

9. The near infrared reflective pigment according to claim 8, wherein The pigment is black.

10. The near infrared reflective pigment according to claim 8, wherein The pigments also include a dispersion solution selected from the group consisting of a liquid capable of uniformly dispersing YIn 1-x-y Mn y Fe x O3.

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