Preparation method of anti-counterfeiting photochromic high-temperature ceramic pigment as well as product and application of anti-counterfeiting photochromic high-temperature ceramic pigment

Abstract

The invention discloses a preparation method of an anti-counterfeiting photochromic high-temperature ceramic pigment as well as a product and application of the anti-counterfeiting photochromic high-temperature ceramic pigment, calcium nitrate, neodymium nitrate and tetraethoxysilane are used as raw materials, and the photochromic-based calcium-neodymium silicate oxyapatite ceramic pigment capable of resisting the high temperature of 1200-1500 DEG C is formed. The high-temperature ceramic pigment and a glaze layer of a ceramic product are fused into a whole, so that the anti-counterfeiting performance of the ceramic product can be effectively improved. The method is suitable for anti-counterfeiting under sunlight irradiation, can generate a color changing effect along with irradiation of light sources with different wavelengths, is remarkable in anti-counterfeiting performance, is beneficial to popularization and application, and has a positive promoting effect on anti-counterfeiting of high-grade porcelain products.

Description

Technical Field

[0001] The present invention relates to the technical field of ceramic pigments, and in particular to a preparation method of a high-temperature ceramic pigment for anti-counterfeiting, and a product and application thereof. Background Art

[0002] In recent years, with the rapid development of the economy, people's demand for high-end porcelain is getting higher and higher. In order to protect the brand image, maintain market order and consumer rights, and prevent counterfeit and shoddy products, ceramic companies usually put anti-counterfeiting marks on ceramic products. Traditional external anti-counterfeiting labels are easy to be torn off or altered, and cannot play an anti-counterfeiting role. For this reason, anti-counterfeiting materials that can be fired on the surface of ceramic products or melted into the glaze layer are favored by ceramic companies. However, the anti-counterfeiting materials fired on the surface of ceramic products cannot withstand the erosion of high-temperature glaze melts and can only be solidified on the ceramic surface at low temperatures (generally below 600°C), which can be easily removed by physical or chemical methods; the anti-counterfeiting materials melted into the glaze layer are lifelong anti-counterfeiting marks because they are fused into the ceramic products and have strong anti-counterfeiting properties.

[0003] At present, the anti-counterfeiting materials that can be melted into the glaze layer reportedly include photoluminescent powder or fluorescent color-changing powder, but the applicable temperature of most photochromic ceramic powders in the existing technology is lower than 1200℃, and they cannot be called high-temperature ceramic powders. There are also studies and developments of photochromic ceramic powders that can be used above 1200℃, but these powders do not show color under sunlight, and only show specific colors under ultraviolet light. Therefore, they can only be called fluorescent powders, not ceramic colorants. Summary of the invention

[0004] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a method for preparing a photochromic high-temperature ceramic colorant for anti-counterfeiting, using calcium nitrate and neodymium nitrate as raw materials to form a photochromic calcium neodymium silicate oxyapatite ceramic colorant that can withstand high temperatures of 1200 to 1500°C, so that it can be fused with the glaze layer of ceramic products to effectively improve the anti-counterfeiting performance of ceramic products. Another purpose of the present invention is to provide products and applications made using the above preparation method.

[0005] The purpose of the present invention is achieved through the following technical solutions:

[0006] The present invention provides a method for preparing a photochromic high-temperature ceramic pigment for anti-counterfeiting, comprising the following steps:

[0007] (1) dissolving calcium nitrate and neodymium nitrate in deionized water and dissolving tetraethyl orthosilicate in anhydrous ethanol at a molar ratio of calcium nitrate:neodymium nitrate:tetraethyl orthosilicate = 0.7-1:4:3-3.5, and mixing and stirring the two solutions to obtain a mixed solution containing calcium, neodymium and silicon;

[0008] (2) adding a precipitant ammonia water to the mixed solution until the pH value of the solution system is 8 to 9, thereby obtaining a precipitate;

[0009] (3) After aging, the precipitate is centrifuged, washed, and dried to obtain a dry precipitate;

[0010] (4) calcining the dried precipitate at a temperature of 1200-1400° C. for 3-5 hours to obtain a calcium-neodymium silicate oxyapatite high-temperature color-changing ceramic pigment with a chemical formula of Ca2Nd8(SiO4)6O2.

[0011] Furthermore, in the step (1) of the present invention, the volume ratio of deionized water to anhydrous ethanol is 1 to 2:1; the concentration of neodymium ions in the mixed solution containing calcium, neodymium and silicon is 0.2 to 0.8 mol / L. The concentration of ammonia water as a precipitant in the step (2) is 1.5 to 2.5 mol / L. The aging time in the step (3) is 12 to 24 hours; the drying temperature is 60 to 80°C, and the drying time is 6 to 12 hours.

[0012] Another object of the present invention is achieved by the following technical solutions:

[0013] The product is prepared by the above-mentioned preparation method of the photochromic high-temperature ceramic pigment for anti-counterfeiting. The application of the product comprises the following steps:

[0014] (1) mixing 4 to 15 wt % of the ceramic colorant and 85 to 96 wt % of a transparent glaze slurry having a sintering temperature of 1200° C. or higher, grinding and sieving to obtain a glaze slurry containing a photochromic ceramic colorant having a solid content of 50 to 65 wt %;

[0015] (2) The glaze slurry containing the photochromic ceramic colorant is applied to the glazed and dried glaze blank by printing, spraying, or smearing, with a coating thickness of 1 to 2 mm. After drying, the glaze slurry is fired in a kiln to obtain a ceramic product that changes color when irradiated with light sources of different wavelengths.

[0016] The present invention has the following beneficial effects:

[0017] (1) The photochromic ceramic pigment prepared by the present invention can withstand the erosion of glaze melt at 1200-1500°C when applied to high-end porcelain anti-counterfeiting technology. Conventional ceramic firing technology can be used. The anti-counterfeiting mark and the glaze layer are fused together, avoiding the shortcomings of existing low-temperature anti-counterfeiting materials that are easy to remove from the product surface or easy to be imitated, and has strong anti-counterfeiting performance.

[0018] (2) The calcium neodymium silicate oxyapatite photochromic ceramic pigment prepared by the present invention has four different absorption peak groups (437nm, 475nm, 519-533nm, 581-591nm) in the visible light range. When the incident light of different wavelengths is changed, the wavelength of its reflected light will also change to produce a color-changing effect.

[0019] (3) The ceramic colorant of the present invention is mixed with the transparent glaze slurry with a sintering temperature of 1200°C or above in the prior art to obtain a photochromic high-temperature (applicable to temperatures above 1200°C) glaze slurry. The ceramic product obtained after glazing and firing can present different colors when illuminated by different light sources within the visible light range, and has significant anti-counterfeiting performance. The present invention is suitable for anti-counterfeiting under sunlight, is conducive to promotion and application, and has a positive role in promoting the anti-counterfeiting of high-end porcelain products. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The present invention will be further described in detail below with reference to the embodiments and accompanying drawings:

[0021] Figure 1 is an XRD diagram of a high temperature ceramic pigment prepared in an embodiment of the present invention;

[0022] Figure 2 is a UV-visible absorption spectrum of the high temperature ceramic pigment prepared in the embodiment of the present invention;

[0023] Figure 3 This is the light discoloration effect of the ceramic product obtained by applying the high-temperature ceramic pigment prepared in Example 1 of the present invention (a: sunlight; b: incandescent lamp; c: fluorescent lamp; d: tri-color fluorescent lamp). DETAILED DESCRIPTION

[0024] Embodiment 1:

[0025] This embodiment provides a method for preparing a photochromic high-temperature ceramic pigment for anti-counterfeiting, and the steps are as follows:

[0026] (1) 3.28 g of calcium nitrate and 26.42 g of neodymium nitrate were added to 100 mL of deionized water and stirred until dissolved; 12.5 g of tetraethyl orthosilicate was added to 100 mL of anhydrous ethanol and stirred until dissolved; the two solutions were mixed and stirred to obtain a clear and transparent mixed solution containing calcium, neodymium and silicon;

[0027] (2) adding a 1.5 mol / L ammonia solution dropwise to the mixed solution until the pH value of the solution system is 8 to obtain a precipitate;

[0028] (3) After aging for 12 h, the precipitate was centrifuged, washed (twice with water and once with alcohol), and dried at 75 °C for 6 h to obtain a dry precipitate;

[0029] (4) The dried precipitate is calcined at 1100°C for 5 hours to obtain a calcium neodymium silicate oxyapatite high temperature color-changing ceramic pigment with a chemical formula of Ca2Nd8(SiO4)6O2.

[0030] Embodiment 2:

[0031] This embodiment provides a method for preparing a photochromic high-temperature ceramic pigment for anti-counterfeiting, and the steps are as follows:

[0032] (1) Add 6.56 g of calcium nitrate and 52.84 g of neodymium nitrate to 100 mL of deionized water and stir until dissolved; add 29.17 g of tetraethyl orthosilicate to 100 mL of anhydrous ethanol and stir until dissolved; mix and stir the two solutions to obtain a clear and transparent mixed solution containing calcium, neodymium and silicon;

[0033] (2) adding a 2 mol / L ammonia solution dropwise to the mixed solution until the pH value of the solution system is 9 to obtain a precipitate;

[0034] (3) After aging for 20 h, the precipitate was centrifuged, washed (twice with water and once with alcohol), and dried at 75 °C for 12 h to obtain a dry precipitate;

[0035] (4) The dried precipitate is calcined at 1300°C for 5 hours to obtain a calcium neodymium silicate oxyapatite high temperature color-changing ceramic pigment with a chemical formula of Ca2Nd8(SiO4)6O2.

[0036] Embodiment three:

[0037] This embodiment provides a method for preparing a photochromic high-temperature ceramic pigment for anti-counterfeiting, and the steps are as follows:

[0038] (1) 1.32 g of calcium nitrate and 13.21 g of neodymium nitrate were added to 100 mL of deionized water and stirred until dissolved; 6.67 g of tetraethyl orthosilicate was added to 100 mL of anhydrous ethanol and stirred until dissolved; the two solutions were mixed and stirred to obtain a clear and transparent mixed solution containing calcium, neodymium and silicon;

[0039] (2) adding a 2 mol / L ammonia solution dropwise to the mixed solution until the pH value of the solution system is 9 to obtain a precipitate;

[0040] (3) After aging for 18 h, the precipitate was centrifuged, washed (twice with water and once with alcohol), and dried at 75 °C for 10 h to obtain a dry precipitate;

[0041] (4) The dried precipitate is calcined at 1200°C for 5 hours to obtain a calcium-neodymium silicate oxyapatite high-temperature color-changing ceramic pigment with a chemical formula of Ca2Nd8(SiO4)6O2.

[0042] like Figure 1 As shown, the high temperature ceramic pigment prepared in the embodiment of the present invention is a calcium neodymium silicate oxyapatite of Ca2Nd8(SiO4)6O2, which is pure in phase and free of impurities. Figure 2 As shown, in the visible light range, there are four different absorption peak groups (437nm, 475nm, 519-533nm, 581-591nm respectively). When the incident light of different wavelengths is changed, the wavelength of the reflected light will also change to produce a color-changing effect.

[0043] Embodiment 4:

[0044] The product obtained by the preparation method of Example 1 is used as follows:

[0045] (1) Weighing 5 g of the ceramic colorant prepared in Example 1 and 95 g of a transparent glaze slurry having a sintering temperature of 1200° C. or higher, mixing them, ball milling for 15 min, and then sifting through a 250-mesh sieve to obtain a glaze slurry having a solid content of 65 wt% and containing a photochromic high-temperature ceramic colorant; wherein the raw material composition of the transparent glaze slurry is 40 wt% of potassium feldspar, 16 wt% of kaolinite, 16 wt% of limestone, 25 wt% of quartz, and 3 wt% of zinc oxide;

[0046] (2) A glaze slurry containing a photochromic high-temperature ceramic colorant is applied to the surface of the glazed and dried glaze blank by spraying, with a coating thickness of 1.5 mm. After drying at 80°C for 12 hours, the glaze slurry is placed in a muffle furnace and calcined at 1270°C to obtain a ceramic product that changes color when irradiated with light sources of different wavelengths.

[0047] like Figure 3 As shown, the ceramic product prepared in this embodiment, when the light sources from left to right are sunlight, incandescent lamp, fluorescent lamp, and three-primary-color fluorescent lamp, the colors are purple, purple-red, light gray-white, and blue, respectively.

Claims

1. A method for preparing a photochromic high-temperature ceramic pigment for anti-counterfeiting, characterized in that The following steps are involved: (1) dissolving calcium nitrate and neodymium nitrate in deionized water and dissolving tetraethyl orthosilicate in anhydrous ethanol at a molar ratio of calcium nitrate:neodymium nitrate:tetraethyl orthosilicate = 0.7-1:4:3-3.5, and mixing and stirring the two solutions to obtain a mixed solution containing calcium, neodymium and silicon; (2) adding a precipitant ammonia water to the mixed solution until the pH value of the solution system is 8 to 9, thereby obtaining a precipitate; (3) After aging, the precipitate is centrifuged, washed, and dried to obtain a dry precipitate; (4) calcining the dried precipitate at a temperature of 1200-1400° C. for 3-5 hours to obtain a calcium-neodymium silicate oxyapatite high-temperature color-changing ceramic pigment with a chemical formula of Ca2Nd8(SiO4)6O2.

2. The method for preparing the anti-counterfeiting photochromic high-temperature ceramic pigment according to claim 1, characterized in that: In the step (1), the volume ratio of deionized water to anhydrous ethanol is 1-2:1; the concentration of neodymium ions in the mixed solution containing calcium, neodymium and silicon is 0.2-0.8 mol / L.

3. The method for preparing the anti-counterfeiting photochromic high-temperature ceramic pigment according to claim 1, characterized in that: The concentration of the precipitant ammonia water in the step (2) is 1.5 to 2.5 mol / L.

4. The method for preparing the anti-counterfeiting photochromic high-temperature ceramic pigment according to claim 1, characterized in that: In the step (3), the aging time is 12 to 24 hours; the drying temperature is 60 to 80° C., and the drying time is 6 to 12 hours.

5. A product obtained by the method for preparing the photochromic high-temperature ceramic pigment for anti-counterfeiting according to any one of claims 1 to 4.

6. Use of the product according to claim 5, characterized in that The following steps are involved: (1) mixing 4 to 15 wt % of the ceramic colorant and 85 to 96 wt % of a transparent glaze slurry having a sintering temperature of 1200° C. or higher, grinding and sieving to obtain a glaze slurry containing a photochromic ceramic colorant having a solid content of 50 to 65 wt %; (2) The glaze slurry containing the photochromic ceramic colorant is applied to the glazed and dried glaze blank by printing, spraying, or smearing, with a coating thickness of 1 to 2 mm. After drying, the glaze slurry is fired in a kiln to obtain a ceramic product that changes color when irradiated with light sources of different wavelengths.

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