Photosensitive invisible anti-counterfeiting ceramic ink as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of ceramic ink, and particularly discloses photosensitive invisible anti-counterfeiting ceramic ink as well as a preparation method and application thereof. The ceramic ink comprises the following raw material components in parts by weight: 35-45 parts of a photosensitive material, 55-60 parts of an organic solvent, 3-8 parts of a dispersing agent and 0.5-1.5 parts of a defoaming agent, wherein the photosensitive material is a rare earth metal oxide. According to the photosensitive invisible anti-counterfeiting ceramic ink, the pure rare-earth metal oxide is used as a photosensitive material, the characteristics that rare-earth elements have an unfilled 4f electron shell layer and 4f electrons are shielded by 5s and 5p electrons on the outer layer are utilized, and when the pure rare-earth metal oxide is excited by external energy, the electrons jump from a ground state energy level to an excited state energy level and then return to the ground state energy level, so that the anti-counterfeiting effect is achieved. An instantaneous luminescence phenomenon can be formed; therefore, the problem of afterglow of a traditional synthetic luminescent material serving as an invisible anti-counterfeiting identification code is solved, and the influence of a photosensitive material on the decorative effect of the ceramic tile 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 counterfeiting, shoddy goods and mixed goods. In order to trace ceramic tile products, a series of anti-counterfeiting related technologies have been formed. The initial 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, since many ceramic tiles have a high degree of sintering, the printed ink information only exists on the bottom or side surface, which can be easily polished off with polishing equipment. At the same time, once the ceramic tiles formed by this scheme are laid, the information cannot be obtained.

[0003] Most of the existing invisible anti-counterfeiting technologies for ceramic tiles have problems such as complex processes, high costs, or impact on the decorative effects of ceramic tiles. For example, a Chinese invention patent (publication number: CN105544921A) discloses a method for making ceramic information identification and a ceramic tile, which punches holes on the side of the ceramic tile and encapsulates the radio frequency card containing information in the hole with curing glue. The ceramic tile prepared by this method destroys the structure of the product and affects the mechanical properties of the product. A Chinese invention patent (publication number: CN114349542A) discloses a method for producing ceramic tiles with invisible anti-counterfeiting functions, which provides an invisible ink, uses an anti-counterfeiting material wrapped in silicate as the solid phase of the ink, and has a complex preparation process. A Chinese invention patent (publication number: CN115433004A) discloses a photoluminescent ceramic powder and its preparation method, ceramic glaze and ink and application. It uses high-temperature synthesized rare earth doped high-temperature luminescent powder as a stealth material. Not only is the process complicated and the cost high; but the use of luminescent powder as a stealth material has the effect of afterglow brightness on the decorative effect of ceramic tiles. That is, when the external light source is withdrawn, due to the afterglow effect, the invisible anti-counterfeiting code information will continue to be displayed for a certain period of time, which has a great impact on 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 solve at least one of the technical problems existing in the above-mentioned prior art. To this end, the present invention proposes a photosensitive invisible anti-counterfeiting ceramic ink and its preparation method and application, which uses the transient luminescence characteristics of rare earth metal oxides as an anti-counterfeiting mark, and can effectively solve the problem that the decorative effect of the product is affected by the afterglow of the existing rare earth doping or rare earth compound luminescent materials; and the raw material cost of the ceramic ink is low and the preparation method is simple.

[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 have extremely complex quasi-linear spectra due to the unfilled 4f electron shell and the shielding of 4f electrons by the outer 5s and 5p electrons. For pure rare earth metal oxides (including single rare earth metal oxides or mixtures of several rare earth metal oxides), under external energy excitation, electrons transition from the ground state energy level to the excited state energy level and then return to the ground state energy level, which will form an instantaneous luminescence phenomenon. For rare earth compounds (including rare earth-containing compounds formed by high-temperature reaction of rare earth metal oxides and other non-rare earth raw materials, or rare earth-doped compounds formed by high-temperature reaction of several rare earth metal oxides), under external energy excitation, electrons will form trap energy levels between the ground state energy level and the excited state energy level. In the process of electrons returning from the excited state energy level to the ground state energy level, some electrons will be confined in the trap energy level. The return of electrons in the trap energy level to the ground state will form afterglow, so doped or multi-component rare earth compounds are prone to produce 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 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, causing different ions to show different colors. Among them, scandium (Sc), yttrium (Y), lanthanum (La), lutetium (Lu), cerium (Ce), europium (Eu), gadolinium (Gd), terbium (Tb) and ytterbium (Yb) have no absorption in the visible light wave range, so these 9 rare earth ions are colorless. Praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), dysprosium (Dy), holmium (Ho), erbium (Er) and thulium (Tm) have absorption in different visible light wave ranges, so these 8 rare earth ions have colors, among which praseodymium is green, neodymium is purple-red, promethium is pink, samarium is yellow, dysprosium is yellow, holmium is pink, erbium is slightly red, and thulium is green. Therefore, the photosensitive material can be selected accordingly according to the actual color needs.

[0010] In some embodiments of the present invention, the maximum particle size of the photosensitive invisible anti-counterfeiting ceramic ink does not exceed 300nm, and the average particle size of the photosensitive invisible anti-counterfeiting ceramic ink is 50-180nm. That is, the maximum particle size of the photosensitive material in the ceramic ink does not exceed 300nm, and the average particle size is 50-180nm. The particle size of the appropriate photosensitive material is not only conducive to achieving transient luminescence, but also conducive to improving 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 is not good under visible light, 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 13 carbon isomeric alkanes to 20 carbon isomeric alkanes.

[0012] Specifically, the morphology of traditional high-temperature synthetic photosensitive materials is difficult to control, and many edges and corners are likely to appear during the grinding process, resulting in the need for a variety of additives to regulate the flow and dispersibility of the ink, such as the need to add anti-leveling agents and leveling agents. The rare earth metal oxides of the present invention have simple ingredients and are not subjected to high-temperature treatment. They have low hardness and are granular after grinding. They are easy to disperse and stabilize, so there is no need to add too many additives to the ink. Studies have found that multi-carbon isomeric alkanes are beneficial to improving the fluidity of inks containing rare earth metal oxides, making inkjet printing smoother.

[0013] In some embodiments of the present invention, the dispersant is selected from at least one of poly(hexamethylenediamine terephthalic acid), poly(hexamethylenediamine terephthalic acid), and poly(meta-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] The second aspect of the present invention provides a method for preparing the above-mentioned photosensitive invisible anti-counterfeiting ceramic ink, comprising the following steps: (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 ceramic ink.

[0017] 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.

[0018] 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%.

[0019] In some embodiments of the present invention, in step (2), the pore size of the filtering filter is 500 nm.

[0020] 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.

[0021] 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.

[0022] 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 .

[0023] The third aspect of the present invention provides the application of the above-mentioned photosensitive invisible anti-counterfeiting ceramic ink.

[0024] In some embodiments of the present invention, the application is a photosensitive invisible anti-counterfeiting ceramic tile, including an invisible anti-counterfeiting code, and the invisible anti-counterfeiting code is inkjet printed by the above-mentioned ceramic ink.

[0025] 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 arranged between the pattern layer and the protective glaze layer.

[0026] The invisible anti-counterfeiting code of the present invention has no specific requirements on the raw material components of the surface glaze layer and the protective glaze layer, and the surface glaze and protective glaze of ordinary glazed ceramic tiles can be used.

[0027] Compared with the prior art, the above technical solution of the present invention has at least the following technical effects or advantages: (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 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 jump from the ground state energy level to the excited state energy level and then return to the ground state energy level, which will form 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 photosensitive materials on the decorative effect of ceramic tiles is avoided.

[0028] (2) When preparing the photosensitive invisible anti-counterfeiting ceramic ink of the present invention, it is not necessary to synthesize the photosensitive material at high temperature, which reduces the difficulty of grinding processing, and the particles after grinding have 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, the preparation process is simple, and it has good industrial application prospects. DETAILED DESCRIPTION

[0029] The present invention is described in detail below in conjunction with the examples, so that the technical personnel of the relevant technical field can understand the present invention. It is necessary to point out here that the examples are only used to further illustrate the present invention and cannot be understood as limiting the scope of protection of the present invention. The non-essential improvements and adjustments made to the present invention by the skilled person in the relevant field according to the above invention content should still belong to 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.

[0030] Example 1 A photosensitive invisible anti-counterfeiting ceramic ink, whose raw material components include, by weight: 35 parts of scandium oxide, 60 parts of carbon 20-isoalkane, 3 parts of polyhexamethylenediamine sebacic acid (number average molecular weight is 800), and 0.5 parts of octylphenol polyoxyethylene ether.

[0031] 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.

[0032] A method for preparing a photosensitive invisible anti-counterfeiting ceramic ink comprises the following steps: (1) Weigh scandium oxide and poly(hexamethylenediamine) sebacic acid according to weight, add them into carbon 20-isoparaffin, and mix and stir with a low-speed stirrer to obtain slurry A; (2) introducing the slurry A prepared in step (1) into a circulating sand mill and grinding for 2.5 hours, wherein 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%; then filtering the ground slurry (the filter element pore size is 500 nm) to obtain slurry B; (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.

[0033] Example 2 A photosensitive invisible anti-counterfeiting ceramic ink, whose raw material components include, by weight: 45 parts of ytterbium oxide, 58 parts of carbon tridecanoids, 8 parts of poly(m-phenylenediamine terephthalic acid) (number average molecular weight is 500), and 1.5 parts of nonylphenol polyoxyethylene ether.

[0034] 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.

[0035] A method for preparing a photosensitive invisible anti-counterfeiting ceramic ink comprises the following steps: (1) Weighing ytterbium oxide and poly(m-phenylenediamine terephthalic acid) in parts by weight, adding them to tridecaned isoparaffin, and mixing and stirring with a low-speed stirrer to obtain slurry A; (2) introducing the slurry A prepared in step (1) into a circulating sand mill and grinding for 3 hours, wherein the grinding medium is zirconia ceramic microbeads with a particle size of 0.3-0.5 mm, and the grinding medium filling rate is 85%; then filtering the ground slurry (the filter element pore size is 500 nm) to obtain slurry B; (3) Add nonylphenol polyoxyethylene ether to the slurry B obtained 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.

[0036] Example 3 A photosensitive invisible anti-counterfeiting ceramic ink, whose raw material components include, by weight: 40 parts of dysprosium oxide, 56 parts of hexadecane, 5 parts of polyhexamethylene terephthalic acid (number average molecular weight is 600), and 1 part of octylphenol polyoxyethylene ether.

[0037] 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.

[0038] A method for preparing a photosensitive invisible anti-counterfeiting ceramic ink comprises the following steps: (1) Weighing dysprosium oxide and poly(hexamethylenediamine terephthalic acid) by weight, adding them into hexadecane, and mixing and stirring with a low-speed stirrer to obtain slurry A; (2) introducing the slurry A prepared in step (1) into a circulating sand mill and grinding for 2.5 hours, wherein the grinding medium is zirconia ceramic microbeads with a particle size of 0.3-0.5 mm, and the grinding medium filling rate is 80%; then filtering the ground slurry (the filter element pore size is 500 nm) to obtain slurry B; (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.

[0039] Example 4 A photosensitive invisible anti-counterfeiting ceramic ink, whose raw material components include, by weight, 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.

[0040] 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.

[0041] A method for preparing a photosensitive invisible anti-counterfeiting ceramic ink comprises the following steps: (1) Weigh lanthanum oxide, europium oxide, poly(hexamethylenediamine terephthalic acid) and poly(hexamethylenediamine terephthalic acid) by weight, add them into 20-carbon isoparaffin, and mix and stir with a low-speed stirrer to obtain slurry A; (2) introducing the slurry A prepared in step (1) into a circulating sand mill and grinding for 2 hours, wherein the grinding medium is zirconia ceramic microbeads with a particle size of 0.3-0.5 mm, and the grinding medium filling rate is 83%; then filtering the ground slurry (the filter element pore size is 500 nm) to obtain slurry B; (3) Add nonylphenol polyoxyethylene ether to the slurry B obtained 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.

[0042] Example 5 A photosensitive invisible anti-counterfeiting ceramic ink, whose raw material components include, by weight: 5 parts of lutetium oxide, 32 parts of samarium oxide, 56 parts of octadecanoic acid, 6 parts of polyhexamethylene terephthalic acid (number average molecular weight is 500), 0.5 parts of octylphenol polyoxyethylene ether, and 0.5 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 85nm.

[0044] A method for preparing a photosensitive invisible anti-counterfeiting ceramic ink comprises the following steps: (1) Lutetium oxide, samarium oxide and poly(hexamethylenediamine terephthalic acid) were weighed in parts by weight, added into 18-isoparaffin, and mixed with a low-speed stirrer to obtain slurry A; (2) introducing the slurry A prepared in step (1) into a circulating sand mill and grinding for 2.5 hours, wherein 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%; then filtering the ground slurry (the filter element pore size is 500 nm) to obtain slurry B; (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.

[0045] Example 6 A photosensitive invisible anti-counterfeiting ceramic ink, whose raw material components include, by weight, 10 parts of europium oxide, 30 parts of dysprosium oxide, 55 parts of carbon 18 isoparaffin, 8 parts of polyhexamethylene terephthalic acid (number average molecular weight is 800), 0.5 parts of octylphenol polyoxyethylene ether, and 1 part of nonylphenol polyoxyethylene ether.

[0046] 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.

[0047] A method for preparing a photosensitive invisible anti-counterfeiting ceramic ink comprises the following steps: (1) Weighing europium oxide, dysprosium oxide and poly(hexamethylenediamine terephthalic acid) by weight, adding them into 18-carbon isoparaffin, and mixing and stirring with a low-speed stirrer to obtain slurry A; (2) introducing the slurry A prepared in step (1) into a circulating sand mill and grinding for 2.5 hours, wherein the grinding medium is zirconia ceramic microbeads with a particle size of 0.3-0.5 mm, and the grinding medium filling rate is 80%; then filtering the ground slurry (the filter element pore size is 500 nm) to obtain slurry B; (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 slurry with a viscosity of 20 mPa·s and a surface tension of 35 mN·m at room temperature. -1 Photosensitive invisible anti-counterfeiting ceramic ink.

[0048] Comparative Example 1 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 300nm, and the average particle size is 50nm.

[0049] Comparative Example 2 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 300nm, and the average particle size is 50nm.

[0050] Comparative Example 3 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.

[0051] Application Examples The invisible anti-counterfeiting ceramic ink prepared in the above-mentioned embodiments 1-6 and comparative examples 1-3 is used to inkjet print invisible anti-counterfeiting codes to make photosensitive invisible anti-counterfeiting ceramic tiles. The specific steps are as follows: The surface of the blank is sequentially poured with top glaze, patterns are inkjet printed, invisible anti-counterfeiting codes are inkjet printed using the above-mentioned photosensitive invisible anti-counterfeiting ceramic ink, and protective glaze is applied to sequentially form a top glaze layer, a pattern layer, an invisible anti-counterfeiting code layer and a protective glaze layer. After drying and firing at 1200°C, photosensitive invisible anti-counterfeiting ceramic tiles are obtained.

[0052] Among them: the body, glaze and protective glaze are all the body, glaze and protective glaze of ordinary glazed tiles on the market.

[0053] Performance Testing The time stability and photosensitivity of the photosensitive invisible anti-counterfeiting ceramic ink samples prepared in the above Examples 1-6 and Comparative Examples 1-3 were tested, and the grinding time was recorded. At the same time, the photosensitivity of the photosensitive invisible anti-counterfeiting ceramic tiles prepared in the application example was tested. Among them: the time stability is based on the CBMF16-2016 "Solvent-based Ceramic Inkjet Printing Ink" standard to test the viscosity value deviation and surface tension deviation of the ink. The greater the viscosity value deviation and surface tension deviation, the worse the stability of the ink; the grinding time refers to the time to grind the ceramic ink to the corresponding particle size; the photosensitivity effect refers to the luminescence under ultraviolet light and visible light. The results are shown in Table 1.

[0054] Table 1:

[0055] As can be seen from Table 1, the photosensitive invisible anti-counterfeiting ceramic ink prepared in Examples 1-6 of the present invention has a short grinding time of only 2-3 hours, which is much lower than the grinding time of the ceramic ink using commercial rare earth doped luminescent powder fired at high temperature in Comparative Example 1-2, and the stability of the ink is also better. At the same time, the photosensitive invisible anti-counterfeiting ceramic ink prepared with rare earth metal oxides in Examples 1-6 and the invisible anti-counterfeiting ceramic tiles prepared therefrom have transient luminescence characteristics under ultraviolet light irradiation, without afterglow; and under visible light, no invisible anti-counterfeiting code outline is visible, and the decorative effect of the product will not be affected. However, the ceramic ink prepared with rare earth doped luminescent powder in Comparative Examples 1-2 will produce afterglow under ultraviolet light irradiation; Comparative Example 3 has a relatively large particle size of the photosensitive material, resulting in the outline of the invisible anti-counterfeiting code being visible under visible light after high temperature firing, which has a certain impact on the decorative effect of the product.

[0056] For ordinary technicians in the technical field to which the present invention belongs, several simple deductions or substitutions can be made without departing from the concept of the present invention, without having to go through creative labor. Therefore, simple improvements made to the present invention by those skilled in the art based on the disclosure of the present invention should be within the protection scope 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 belong to the protection scope 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 rare earth metal oxide.

2. The photosensitive invisible anti-counterfeiting ceramic ink according to claim 1, characterized in that: 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.

3. The photosensitive invisible anti-counterfeiting ceramic ink according to claim 1 or 2, characterized in that: 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.

4. The photosensitive invisible anti-counterfeiting ceramic ink according to claim 1, characterized in that: The organic solvent is a polyisomeric alkane having 13 to 22 carbon atoms.

5. The photosensitive invisible anti-counterfeiting ceramic ink according to claim 1, characterized in that: The dispersant is selected from at least one of polyhexamethylenediamine sebacic acid, polyhexamethylenediamine terephthalic acid and poly-m-phenylenediamine terephthalic acid.

6. The photosensitive invisible anti-counterfeiting ceramic ink according to claim 1, characterized in that: The defoaming agent is octylphenol polyoxyethylene ether and / or nonylphenol polyoxyethylene ether.

7. A method for preparing the photosensitive invisible anti-counterfeiting ceramic ink according to any one of claims 1 to 6, 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.

8. The method for preparing the photosensitive invisible anti-counterfeiting ceramic ink according to claim 7, characterized in that: The viscosity of the photosensitive invisible anti-counterfeiting ceramic ink at room temperature is 5-25 mPa·s.

9. The method for preparing the photosensitive invisible anti-counterfeiting ceramic ink according to claim 7, characterized in that: The surface tension of the photosensitive invisible anti-counterfeiting ceramic ink is 30-35 mN·m -1 .

10. A photosensitive invisible anti-counterfeiting ceramic tile, characterized in that: It comprises an invisible anti-counterfeiting code, which is formed by inkjet printing of the photosensitive invisible anti-counterfeiting ceramic ink according to any one of claims 1 to 6.

Images