A photosensitive invisible anti-counterfeiting ceramic ink and its preparation method and application

Abstract

The present invention belongs to the field of ceramic ink technology, and specifically discloses a photosensitive invisible anti-counterfeiting ceramic ink and its preparation method and application. The raw material components of the ceramic ink include, by weight: 35-45 parts of photosensitive material, 55-60 parts of organic solvent, 3-8 parts of dispersant, and 0.5-1.5 parts of defoaming agent; wherein: the photosensitive material is a rare earth metal oxide. The photosensitive invisible anti-counterfeiting ceramic ink of the present invention uses pure rare earth metal oxide as the photosensitive material, and utilizes the characteristics that rare earth elements have an unfilled 4f electron shell and the 4f electrons are shielded by the outer 5s and 5p electrons. When the pure rare earth metal oxide is excited by external energy, the electrons transition from the ground state energy level to the excited state energy level and then return to the ground state energy level, forming an instantaneous luminescence phenomenon; therefore, the afterglow problem existing in traditional synthetic luminescent materials as invisible anti-counterfeiting identification codes is solved, and the influence of the photosensitive material on the decorative effect of ceramic tiles is avoided.

Description

Technical Field

[0001] The present invention belongs to the technical field of ceramic inks, and in particular relates to a photosensitive invisible anti-counterfeiting ceramic ink and a preparation method and application thereof. Background Art

[0002] With the widespread application of inkjet printing decoration technology in the building ceramics industry, the decoration of ceramic tiles has become more homogenized, which has also led to frequent incidents of counterfeiting, substandard products, and mixed goods. In order to trace ceramic tile products, a series of anti-counterfeiting related technologies have been developed. The original anti-counterfeiting traceability information was attached to the product packaging, and the information could be easily erased by changing the packaging. Currently, the most widely used method is to print traditional ink coding information on the bottom or side of the ceramic tile. However, due to the high degree of sintering of many ceramic tiles, the printed ink information only exists on the bottom or side surface and can be easily polished off with polishing equipment. At the same time, once the ceramic tiles formed by this solution are laid, the information cannot be obtained.

[0003] Existing invisible anti-counterfeiting technologies for ceramic tiles often suffer from complex processes, high costs, or impacts on the decorative effect of the tiles. For example, a Chinese invention patent (publication number: CN105544921A) discloses a method for manufacturing ceramic information identification tiles and ceramic tiles. This method involves punching holes in the side of the ceramic tile and encapsulating a radio frequency card containing information within the hole using curing adhesive. However, this method compromises the product's structure and affects its mechanical properties. A Chinese invention patent (publication number: CN114349542A) discloses a method for producing ceramic tiles with invisible anti-counterfeiting features. This method provides an invisible ink using a silicate-coated anti-counterfeiting material as the ink's solid phase, resulting in a complex preparation process. A Chinese invention patent (publication number: CN115433004A) discloses a photoluminescent ceramic powder, its preparation method, ceramic glaze, ink, and applications. The powder uses a high-temperature synthesized rare earth-doped high-temperature luminescent powder as a stealth material. This process is complex and costly. Furthermore, the use of luminescent powder as a stealth material can affect the decorative effect of ceramic tiles due to the afterglow brightness. That is, after the external light source is removed, the invisible anti-counterfeiting code information will continue to display for a certain period of time due to the afterglow effect, significantly affecting the decorative effect of the product.

[0004] Therefore, there is an urgent need to develop an invisible anti-counterfeiting ceramic ink that not only does not affect the decorative effect of ceramic tiles, but also has a simple and easy preparation method and is suitable for industrial production. Summary of the Invention

[0005] The present invention aims to address at least one of the technical problems existing in the aforementioned prior art. To this end, the present invention provides a photosensitive invisible anti-counterfeiting ceramic ink, its preparation method, and its application. This ceramic ink utilizes the transient luminescence properties of rare earth metal oxides as an anti-counterfeiting mark, effectively resolving the issue of afterglow in existing rare earth-doped or rare earth compound luminescent materials, which can affect the decorative effect of products. Furthermore, the ceramic ink has low raw material costs and is simple to prepare.

[0006] To solve the above technical problems, the first aspect of the present invention provides a photosensitive invisible anti-counterfeiting ceramic ink, whose raw material components include, by weight: 35-45 parts of photosensitive material, 55-60 parts of organic solvent, 3-8 parts of dispersant, and 0.5-1.5 parts of defoaming agent; the photosensitive material is a rare earth metal oxide.

[0007] Research has found that rare earth elements exhibit extremely complex, quasi-linear spectra due to their unfilled 4f electron shells and the shielding of 4f electrons by outer 5s and 5p electrons. For pure rare earth oxides (including single rare earth oxides or mixtures of several rare earth oxides), when excited by external energy, electrons transition from the ground state to the excited state and then back to the ground state, resulting in transient luminescence. For rare earth compounds (including rare earth-containing compounds formed by the high-temperature reaction of rare earth oxides with other non-rare earth raw materials, or rare earth-doped compounds formed by the high-temperature reaction of several rare earth oxides), when excited by external energy, electrons form trap levels between the ground and excited states. During the process of electrons returning from the excited state to the ground state, some electrons become trapped in the trap levels. The return of trapped electrons to the ground state produces afterglow, resulting in the formation of an afterglow effect. Therefore, doped or multi-component rare earth compounds are prone to the afterglow effect. The ceramic ink of the present invention uses pure rare earth metal oxide as a photosensitive material, which can effectively solve the afterglow problem existing in traditional synthetic luminescent materials used as invisible anti-counterfeiting identification codes, thereby affecting the decorative effect of the product.

[0008] In some embodiments of the present invention, the photosensitive material is selected from at least one of scandium oxide, yttrium oxide, lanthanum oxide, lutetium oxide, cerium oxide, europium oxide, gadolinium oxide, terbium oxide, ytterbium oxide, praseodymium oxide, neodymium oxide, promethium oxide, samarium oxide, dysprosium oxide, holmium oxide, erbium oxide, and thulium oxide.

[0009] Specifically, rare earth ions have different absorption peaks in the visible light wavelength range, resulting in different colors. Scandium (Sc), yttrium (Y), lanthanum (La), lutetium (Lu), cerium (Ce), europium (Eu), gadolinium (Gd), terbium (Tb), and ytterbium (Yb) do not absorb light in the visible light range, making these nine rare earth ions colorless. Praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), dysprosium (Dy), holmium (Ho), erbium (Er), and thulium (Tm) absorb light in different visible light wavelength ranges, resulting in these eight rare earth ions having different colors: praseodymium appears green, neodymium appears purple-red, promethium appears pink, samarium appears yellow, dysprosium appears yellow, holmium appears pink, erbium appears reddish, and thulium appears green. Therefore, the photosensitive material can be selected based on the desired color.

[0010] In some embodiments of the present invention, the maximum particle size of the photosensitive invisible anti-counterfeiting ceramic ink does not exceed 300 nm, and the average particle size of the photosensitive invisible anti-counterfeiting ceramic ink is 50-180 nm. That is, the maximum particle size of the photosensitive material in the ceramic ink does not exceed 300 nm, and the average particle size is 50-180 nm. An appropriate particle size of the photosensitive material not only facilitates transient luminescence but also improves the stability of the ink. Studies have found that when the particle size of the photosensitive material is too large, after high-temperature firing, its invisible effect under visible light is poor, which will have a certain impact on the decorative effect of the product.

[0011] In some embodiments of the present invention, the organic solvent is a polyisomeric alkane having 13 to 22 carbon atoms, that is, from tridecanes to eicosanes.

[0012] Specifically, the morphology of traditional high-temperature synthetic photosensitive materials is difficult to control, and many sharp corners easily appear during the grinding process. This results in the ink's flow and dispersibility requiring various additives, such as anti-flattening agents and leveling agents. However, the rare earth metal oxides of the present invention have simple compositions and are not subjected to high-temperature treatment, resulting in a relatively low hardness. After grinding, they form granules that are easily dispersed and stable, thus eliminating the need for excessive additives in the ink. Research has found that multi-carbon isoalkanes can improve the flow of inks containing rare earth metal oxides, enabling smoother inkjet printing.

[0013] In some embodiments of the present invention, the dispersant is selected from at least one of polyhexamethylenediamine sebacic acid, polyhexamethylenediamine terephthalic acid, and poly(m-phenylenediamine terephthalic acid).

[0014] In some embodiments of the present invention, the number average molecular weight of the dispersant is 500-800.

[0015] In some embodiments of the present invention, the defoaming agent is octylphenol polyoxyethylene ether and / or nonylphenol polyoxyethylene ether.

[0016] A second aspect of the present invention provides a method for preparing the above-mentioned photosensitive invisible anti-counterfeiting ceramic ink, comprising the following steps:

[0017] (1) Adding a photosensitive material and a dispersant into an organic solvent and mixing them to obtain slurry A;

[0018] (2) Grinding and filtering the slurry A to obtain slurry B;

[0019] (3) Add a defoaming agent to the slurry B and mix them to obtain the ceramic ink.

[0020] In some embodiments of the present invention, in step (1), the maximum particle size of the photosensitive material does not exceed 30 μm, that is, the initial particle size of the photosensitive material does not exceed 30 μm, so as to improve the grinding efficiency.

[0021] In some embodiments of the present invention, in step (2), the grinding is performed using ultrafine grinding equipment (such as a circulating sand mill), the grinding medium is zirconia ceramic microbeads with a particle size of 0.3-0.5 mm, and the grinding medium filling rate is 75-85%.

[0022] In some embodiments of the present invention, in step (2), the pore size of the filtration filter is 500 nm.

[0023] In some embodiments of the present invention, in step (3), the mixing is carried out by stirring with a high-speed stirrer, and the stirring speed is 600-800 rpm.

[0024] In some embodiments of the present invention, in step (3), the viscosity of the photosensitive invisible anti-counterfeiting ceramic ink at room temperature (25° C.) is 5-25 mPa·s.

[0025] In some embodiments of the present invention, in step (3), the surface tension of the photosensitive invisible anti-counterfeiting ceramic ink is 30-35 mN·m -1 .

[0026] The third aspect of the present invention provides the application of the above-mentioned photosensitive invisible anti-counterfeiting ceramic ink.

[0027] In some embodiments of the present invention, the application is a photosensitive invisible anti-counterfeiting ceramic tile, including an invisible anti-counterfeiting code, which is inkjet printed by the above-mentioned ceramic ink.

[0028] In some embodiments of the present invention, the photosensitive invisible anti-counterfeiting ceramic tile includes, from bottom to bottom, a body, a surface glaze layer, a pattern layer and a protective glaze layer, and the invisible anti-counterfeiting code is provided between the pattern layer and the protective glaze layer.

[0029] The invisible anti-counterfeiting code of the present invention has no special requirements on the raw material components of the surface glaze layer and the protective glaze layer, and can adopt the surface glaze and protective glaze of ordinary glazed ceramic tiles.

[0030] Compared with the prior art, the above technical solution of the present invention has at least the following technical effects or advantages:

[0031] (1) The photosensitive invisible anti-counterfeiting ceramic ink of the present invention uses pure rare earth metal oxide as the photosensitive material. It utilizes the characteristics that rare earth elements have unfilled 4f electron shells and 4f electrons are shielded by the outer 5s and 5p electrons. When the pure rare earth metal oxide is excited by external energy, the electrons jump from the ground state energy level to the excited state energy level and then return to the ground state energy level, forming an instantaneous luminescence phenomenon. Therefore, it solves the afterglow problem existing in traditional synthetic luminescent materials as invisible anti-counterfeiting identification codes and avoids the influence of photosensitive materials on the decorative effect of ceramic tiles.

[0032] (2) The photosensitive invisible anti-counterfeiting ceramic ink of the present invention does not require high-temperature synthesis of the photosensitive material during preparation, which reduces the difficulty of grinding processing. The particles after grinding have a regular morphology, thereby improving the stability of the ceramic ink and reducing the phenomenon of nozzle clogging during inkjet printing. At the same time, the raw materials of the ceramic ink are simple and easy to obtain, and the preparation process is simple, which has good prospects for industrial application. DETAILED DESCRIPTION

[0033] The present invention is described in detail below with reference to the examples to facilitate understanding of the present invention by those skilled in the art. It is necessary to point out that the examples are only used to further illustrate the present invention and are not to be construed as limiting the scope of protection of the present invention. Non-essential improvements and adjustments made to the present invention by those skilled in the art based on the above-mentioned invention should still fall within the scope of protection of the present invention. At the same time, the raw materials mentioned below that are not described in detail are all commercially available products; the process steps or preparation methods that are not mentioned in detail are all process steps or preparation methods known to those skilled in the art.

[0034] Example 1

[0035] A photosensitive invisible anti-counterfeiting ceramic ink, whose raw material components include, by weight, 35 parts of scandium oxide, 60 parts of carbon 2-isoparaffin, 3 parts of polyhexamethylenediamine sebacic acid (number average molecular weight of 800), and 0.5 parts of octylphenol polyoxyethylene ether.

[0036] Among them: the maximum particle size of the photosensitive invisible anti-counterfeiting ceramic ink does not exceed 300nm, and the average particle size is 50nm.

[0037] A method for preparing a photosensitive invisible anti-counterfeiting ceramic ink comprises the following steps:

[0038] (1) Scandium oxide and poly(hexamethylenediamine) sebacic acid were weighed in parts by weight, added to 20-isoparaffin, and mixed with a low-speed stirrer to obtain slurry A;

[0039] (2) Slurry A prepared in step (1) was introduced into a circulating sand mill and ground for 2.5 hours, wherein the grinding medium was zirconia ceramic microbeads with a particle size of 0.3-0.5 mm and the grinding medium filling rate was 75%; the ground slurry was then filtered (the filter element pore size was 500 nm) to obtain slurry B;

[0040] (3) Octylphenol polyoxyethylene ether was added to the slurry B obtained in step (2), and stirred at 600 rpm using a high-speed stirrer to obtain a viscosity of 25 mPa·s and a surface tension of 32 mN·m at room temperature. -1 Photosensitive invisible anti-counterfeiting ceramic ink.

[0041] Example 2

[0042] A photosensitive invisible anti-counterfeiting ceramic ink, whose raw material components include, by weight, 45 parts of ytterbium oxide, 58 parts of carbon 13 isoparaffin, 8 parts of poly(m-phenylenediamine terephthalic acid) (number average molecular weight of 500), and 1.5 parts of nonylphenol polyoxyethylene ether.

[0043] Among them: the maximum particle size of the photosensitive invisible anti-counterfeiting ceramic ink does not exceed 300nm, and the average particle size is 180nm.

[0044] A method for preparing a photosensitive invisible anti-counterfeiting ceramic ink comprises the following steps:

[0045] (1) Weighing ytterbium oxide and poly(m-phenylenediamine terephthalic acid) by weight, adding them to tridecanol, and mixing with a low-speed stirrer to obtain slurry A;

[0046] (2) Slurry A prepared in step (1) was introduced into a circulating sand mill and ground for 3 hours, wherein the grinding medium was zirconia ceramic microbeads with a particle size of 0.3-0.5 mm and the grinding medium filling rate was 85%; the ground slurry was then filtered (the filter pore size was 500 nm) to obtain slurry B;

[0047] (3) Add nonylphenol polyoxyethylene ether to the slurry B prepared in step (2), and stir at 800 rpm using a high-speed stirrer to obtain a viscosity of 5 mPa·s and a surface tension of 30 mN·m at room temperature. -1 Photosensitive invisible anti-counterfeiting ceramic ink.

[0048] Example 3

[0049] A photosensitive invisible anti-counterfeiting ceramic ink, whose raw material components, measured by weight, include: 40 parts of dysprosium oxide, 56 parts of hexadecane, 5 parts of polyhexamethylene terephthalic acid (number average molecular weight of 600), and 1 part of octylphenol polyoxyethylene ether.

[0050] Among them: the maximum particle size of the photosensitive invisible anti-counterfeiting ceramic ink does not exceed 300nm, and the average particle size is 100nm.

[0051] A method for preparing a photosensitive invisible anti-counterfeiting ceramic ink comprises the following steps:

[0052] (1) Weighing dysprosium oxide and poly(hexamethylenediamine terephthalic acid) by weight, adding them to hexadecane, and mixing them with a low-speed stirrer to obtain slurry A;

[0053] (2) Slurry A prepared in step (1) was introduced into a circulating sand mill and ground for 2.5 hours, wherein the grinding medium was zirconia ceramic microbeads with a particle size of 0.3-0.5 mm and the grinding medium filling rate was 80%; the ground slurry was then filtered (the filter pore size was 500 nm) to obtain slurry B;

[0054] (3) Octylphenol polyoxyethylene ether was added to the slurry B obtained in step (2), and stirred at 700 rpm using a high-speed stirrer to obtain a viscosity of 15 mPa·s and a surface tension of 32 mN·m at room temperature. -1 Photosensitive invisible anti-counterfeiting ceramic ink.

[0055] Example 4

[0056] A photosensitive invisible anti-counterfeiting ceramic ink, whose raw material components, measured by weight, include: 15 parts of lanthanum oxide, 25 parts of europium oxide, 60 parts of carbon 2-isoparaffin, 3 parts of polyhexamethylenediamine sebacic acid (number average molecular weight of 700), 2 parts of polyhexamethylenediamine terephthalic acid (number average molecular weight of 600), and 0.5 parts of nonylphenol polyoxyethylene ether.

[0057] Among them: the maximum particle size of the photosensitive invisible anti-counterfeiting ceramic ink does not exceed 300nm, and the average particle size is 150nm.

[0058] A method for preparing a photosensitive invisible anti-counterfeiting ceramic ink comprises the following steps:

[0059] (1) Weigh lanthanum oxide, europium oxide, poly(hexamethylenediamine terephthalic acid) and poly(hexamethylenediamine terephthalic acid) in parts by weight, add them to 20-isoparaffin, and mix and stir with a low-speed stirrer to obtain slurry A;

[0060] (2) Slurry A prepared in step (1) was introduced into a circulating sand mill and ground for 2 hours, wherein the grinding medium was zirconia ceramic microbeads with a particle size of 0.3-0.5 mm and the grinding medium filling rate was 83%; the ground slurry was then filtered (the filter pore size was 500 nm) to obtain slurry B;

[0061] (3) Add nonylphenol polyoxyethylene ether to the slurry B prepared in step (2), and stir at 600 rpm using a high-speed stirrer to obtain a viscosity of 20 mPa·s and a surface tension of 35 mN·m at room temperature. -1 Photosensitive invisible anti-counterfeiting ceramic ink.

[0062] Example 5

[0063] A photosensitive invisible anti-counterfeiting ceramic ink, the raw material components of which are calculated by weight: 5 parts of lutetium oxide, 32 parts of samarium oxide, 56 parts of octadecyl isoparaffin, 6 parts of polyhexamethylenediamine terephthalic acid (number average molecular weight of 500), 0.5 parts of octylphenol polyoxyethylene ether, and 0.5 parts of nonylphenol polyoxyethylene ether.

[0064] Among them: the maximum particle size of the photosensitive invisible anti-counterfeiting ceramic ink does not exceed 300nm, and the average particle size is 85nm.

[0065] A method for preparing a photosensitive invisible anti-counterfeiting ceramic ink comprises the following steps:

[0066] (1) Lutetium oxide, samarium oxide, and poly(hexamethylenediamine terephthalic acid) were weighed in parts by weight, added to 18-isoparaffin, and mixed with a low-speed stirrer to obtain slurry A;

[0067] (2) Slurry A prepared in step (1) was introduced into a circulating sand mill and ground for 2.5 hours, wherein the grinding medium was zirconia ceramic microbeads with a particle size of 0.3-0.5 mm and the grinding medium filling rate was 75%; the ground slurry was then filtered (the filter element pore size was 500 nm) to obtain slurry B;

[0068] (3) Octylphenol polyoxyethylene ether and nonylphenol polyoxyethylene ether were added to the slurry B prepared in step (2), and stirred at 750 rpm using a high-speed stirrer to obtain a viscosity of 5 mPa·s and a surface tension of 31 mN·m at room temperature. -1 Photosensitive invisible anti-counterfeiting ceramic ink.

[0069] Example 6

[0070] A photosensitive invisible anti-counterfeiting ceramic ink, whose raw material components, measured by weight, include: 10 parts of europium oxide, 30 parts of dysprosium oxide, 55 parts of octadecyl isoparaffin, 8 parts of polyhexamethylenediamine terephthalic acid (number average molecular weight of 800), 0.5 parts of octylphenol polyoxyethylene ether, and 1 part of nonylphenol polyoxyethylene ether.

[0071] Among them: the maximum particle size of the photosensitive invisible anti-counterfeiting ceramic ink does not exceed 300nm, and the average particle size is 150nm.

[0072] A method for preparing a photosensitive invisible anti-counterfeiting ceramic ink comprises the following steps:

[0073] (1) Weighing europium oxide, dysprosium oxide, and poly(hexamethylenediamine terephthalic acid) by weight, adding them to 18-isoparaffin, and mixing with a low-speed stirrer to obtain slurry A;

[0074] (2) Slurry A prepared in step (1) was introduced into a circulating sand mill and ground for 2.5 hours, wherein the grinding medium was zirconia ceramic microbeads with a particle size of 0.3-0.5 mm and the grinding medium filling rate was 80%; the ground slurry was then filtered (the filter pore size was 500 nm) to obtain slurry B;

[0075] (3) Octylphenol polyoxyethylene ether and nonylphenol polyoxyethylene ether were added to the slurry B prepared in step (2), and stirred at 700 rpm using a high-speed stirrer to obtain a viscosity of 20 mPa·s and a surface tension of 35 mN·m at room temperature. -1 Photosensitive invisible anti-counterfeiting ceramic ink.

[0076] Comparative Example 1

[0077] The difference between Comparative Example 1 and Example 1 is that the photosensitive material in the photosensitive invisible anti-counterfeiting ceramic ink is different. Comparative Example 1 replaces the scandium oxide in Example 1 with an equal amount of commercially available rare earth-doped luminescent powder SrAl2O4:Eu,Dy. The maximum particle size of the ceramic ink does not exceed 300 nm, and the average particle size is 50 nm.

[0078] Comparative Example 2

[0079] The difference between Comparative Example 2 and Example 1 is that the photosensitive material in the photosensitive invisible anti-counterfeiting ceramic ink is different. Comparative Example 2 replaces the scandium oxide in Example 1 with an equal amount of commercially available rare earth-doped luminescent powder Ca2MgSi2O7:Eu,Dy. The maximum particle size of the ceramic ink does not exceed 300 nm, and the average particle size is 50 nm.

[0080] Comparative Example 3

[0081] The difference between Comparative Example 3 and Example 1 is that the maximum particle size of the photosensitive invisible anti-counterfeiting ceramic ink does not exceed 750 nm, and the average particle size is 450 nm.

[0082] Application Examples

[0083] The invisible anti-counterfeiting ceramic inks prepared in Examples 1-6 and Comparative Examples 1-3 are used to inkjet print invisible anti-counterfeiting codes to produce photosensitive invisible anti-counterfeiting ceramic tiles. The specific steps are as follows:

[0084] The surface of the blank is sequentially coated with top glaze, pattern is inkjet printed, invisible anti-counterfeiting code is inkjet printed using the above-mentioned photosensitive invisible anti-counterfeiting ceramic ink, and protective glaze is applied to form top glaze layer, pattern layer, invisible anti-counterfeiting code layer and protective glaze layer in sequence. After drying and firing at 1200°C, photosensitive invisible anti-counterfeiting ceramic tiles are obtained.

[0085] Among them: the body, surface glaze and protective glaze are all the body, surface glaze and protective glaze of ordinary glazed tiles on the market.

[0086] Performance Testing

[0087] The temporal stability and photosensitivity of the photosensitive invisible anti-counterfeiting ceramic ink samples prepared in Examples 1-6 and Comparative Examples 1-3 were tested, and their grinding time was recorded. Simultaneously, the photosensitivity of the photosensitive invisible anti-counterfeiting ceramic tiles prepared in the application examples was tested. Temporal stability was tested according to the CBMF16-2016 "Solvent-Based Ceramic Inkjet Printing Inks" standard, measuring the viscosity deviation and surface tension deviation of the ink. Greater viscosity and surface tension deviations indicate poorer ink stability. Grinding time refers to the time required to grind the ceramic ink to the appropriate particle size. Photosensitivity refers to luminescence under ultraviolet and visible light. The results are shown in Table 1.

[0088] Table 1:

[0089]

[0090] As shown in Table 1, the photosensitive invisible anti-counterfeiting ceramic inks prepared in Examples 1-6 of the present invention require a short grinding time of only 2-3 hours, significantly less than the grinding time of the ceramic inks in Comparative Examples 1-2, which utilize commercially available rare earth-doped luminescent powders sintered at high temperatures. Furthermore, the inks exhibit superior stability. Furthermore, the photosensitive invisible anti-counterfeiting ceramic inks prepared using rare earth metal oxides in Examples 1-6, and the invisible anti-counterfeiting ceramic tiles prepared therefrom, exhibit transient luminescence under ultraviolet light, without any afterglow. Furthermore, the outline of the invisible anti-counterfeiting code is not visible under visible light, thus negatively impacting the decorative effect of the product. In contrast, the ceramic inks prepared using rare earth-doped luminescent powders in Comparative Examples 1-2 exhibit an afterglow under ultraviolet light, and the outline of the invisible anti-counterfeiting code in Comparative Example 3, due to the relatively large particle size of the photosensitive material, is visible under visible light after high-temperature sintering, impacting the decorative effect of the product.

[0091] For those skilled in the art to which the present invention belongs, a number of simple deductions or substitutions can be made without departing from the concept of the present invention, without having to resort to creative work. Therefore, based on the disclosure of the present invention, simple improvements made by those skilled in the art to the present invention should be within the scope of protection of the present invention. The above embodiments are preferred embodiments of the present invention, and all processes similar to the present invention and equivalent changes made should fall within the scope of protection of the present invention.

Claims

1. A photosensitive invisible anti-counterfeiting ceramic ink, characterized in that: The raw material components include, by weight: 35-45 parts of photosensitive material, 55-60 parts of organic solvent, 3-8 parts of dispersant, and 0.5-1.5 parts of defoaming agent; The photosensitive material is selected from at least one of scandium oxide, lanthanum oxide, europium oxide, and ytterbium oxide; The maximum particle size of the photosensitive invisible anti-counterfeiting ceramic ink does not exceed 300 nm, and the average particle size of the photosensitive invisible anti-counterfeiting ceramic ink is 50-180 nm; The organic solvent is a polyisomeric hydrocarbon having 13 to 22 carbon atoms, the defoaming agent is octylphenol polyoxyethylene ether and / or nonylphenol polyoxyethylene ether, and the dispersant is selected from at least one of polyhexamethylenediamine sebacic acid, polyhexamethylenediamine terephthalic acid, and poly(m-phenylenediamine terephthalic acid); The surface tension of the photosensitive invisible anti-counterfeiting ceramic ink is 30-35 mN·m -1 .

2. A method for preparing the photosensitive invisible anti-counterfeiting ceramic ink according to claim 1, characterized in that: The following steps are involved: (1) Adding a photosensitive material and a dispersant into an organic solvent and mixing them to obtain slurry A; (2) Grinding and filtering the slurry A to obtain slurry B; (3) Add a defoaming agent to the slurry B and mix them to obtain the photosensitive invisible anti-counterfeiting ceramic ink.

3. The method for preparing the photosensitive invisible anti-counterfeiting ceramic ink according to claim 2, characterized in that: The viscosity of the photosensitive invisible anti-counterfeiting ceramic ink at room temperature is 5-25 mPa·s.

4. A photosensitive invisible anti-counterfeiting ceramic tile, characterized in that: The invention comprises an invisible anti-counterfeiting code, wherein the invisible anti-counterfeiting code is formed by inkjet printing using the photosensitive invisible anti-counterfeiting ceramic ink according to claim 1.

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