A highly stable ceramic ink and preparation method thereof

Abstract

The present application provides a highly stable ceramic ink and a preparation method thereof. The highly stable ceramic ink comprises the following components by weight: 30 parts of an inorganic pigment, 2-8 parts of a sulfonic acid block polymer, 1-3 parts of polyvinyl alcohol grafted glycidyl methacrylate, and 50-70 parts of an organic solvent; wherein the polyvinyl alcohol grafted glycidyl methacrylate contains multiple epoxy groups. By constructing a composite system containing a sulfonic acid block polymer dispersant and polyvinyl alcohol grafted glycidyl methacrylate, the highly stable ceramic ink achieves stable dispersion of the inorganic pigment, thermal anchoring of the inkjet pattern area, and optimized glaze layer fusion compatibility. This effectively addresses the issues of blurred pattern boundaries and glaze-ink separation that plague existing ceramic inks during high-temperature sintering. Consequently, the highly stable ceramic ink exhibits excellent storage stability and resistance to glaze-ink separation.

Description

Technical Field

[0001] The present application relates to the technical field of ceramic inks, and in particular to a highly stable ceramic ink and a preparation method thereof. Background Art

[0002] Ceramic inks are widely used in digital ceramic inkjet printing processes, primarily for creating colorful patterns, textures, or functional layers on ceramic tile surfaces. This technology, with its advantages of eliminating the need for platemaking, flexible and variable patterns, and high automation, is gradually replacing traditional screen and roller printing methods and becoming the mainstream technology in tile decoration.

[0003] Existing ceramic inks typically consist of inorganic pigments, organic or inorganic dispersants, organic solvents, and various functional additives (such as wetting agents, leveling agents, and defoamers). The core components are the inorganic pigment and the dispersion system. Commonly used inorganic pigments are metal oxides with particle sizes below 1μm, such as iron oxide red, cobalt blue, copper chromium black, and zirconium yellow. The particle characteristics of these pigments directly determine the ink's jetting performance, pattern definition, and final sintering quality. Since the aperture of inkjet printheads is typically between 20 and 30μm, high requirements are placed on the ink's particle size distribution, dispersion stability, viscosity, and surface tension.

[0004] To ensure stable suspension and uniform distribution of pigments during the printing process and to prevent sedimentation during long-term storage, ceramic inks generally use various polymer dispersants or small molecule surfactants. Commonly used dispersants include polycarboxylates and polyether-modified polymers, which aim to stabilize the dispersion of inorganic pigments through the dual mechanisms of electrostatic repulsion and steric hindrance. However, under high solid content, high-temperature drying and sintering process conditions, existing dispersants often face problems such as insufficient stability and poor anchoring after pyrolysis. These defects can lead to "glaze-ink separation," "blurred edges," or "lack of adhesion" in the patterned area, affecting the final decorative quality.

[0005] Furthermore, the sintering behavior of ceramic inks is also influenced by the degree of pigment surface modification, the residual dispersant structure, and the interfacial synergy between the inkjet pattern and the glaze layer. Current technologies lack effective anchoring or structural locking mechanisms within the printed pattern area. This is particularly true for designs overlaying patterns with transparent glazes, which can lead to post-firing pattern fading, blurred outlines, and ink migration.

[0006] Therefore, how to improve the dispersion stability, pattern thermal stability and post-firing interface fusion effect of ceramic inks is a key technical problem that needs to be urgently solved in the field of ceramic inks. Summary of the Invention

[0007] The present application provides a highly stable ceramic ink and a preparation method thereof. The highly stable ceramic ink achieves stable dispersion of pigments, construction of thermal anchoring structure of inkjet pattern area, and optimization of glaze layer fusion compatibility by constructing a composite system containing a sulfonic acid block polymer dispersant and polyvinyl alcohol grafted glycidyl methacrylate. It effectively solves the problems of blurred pattern boundaries and glaze-ink separation during high-temperature sintering of existing ceramic inks, and improves the imaging stability and post-firing quality consistency of ceramic inkjet patterns.

[0008] In the first aspect, the present application provides a highly stable ceramic ink comprising the following components in parts by mass: 30 parts of inorganic pigment, 2 to 8 parts of sulfonic acid block polymer, 1 to 3 parts of polyvinyl alcohol grafted glycidyl methacrylate, and 50 to 70 parts of organic solvent; wherein the polyvinyl alcohol grafted glycidyl methacrylate contains multiple epoxy groups.

[0009] According to the present application, the highly stable ceramic ink achieves stable dispersion of inorganic pigments, construction of thermal anchoring structure of inkjet pattern area and optimization of glaze layer fusion compatibility by constructing a composite system containing sulfonic acid block polymer dispersant and polyvinyl alcohol grafted glycidyl methacrylate, which effectively solves the problems of blurred pattern boundaries and glaze-ink separation in the high-temperature sintering process of existing ceramic inks. Therefore, the highly stable ceramic ink has good storage stability and resistance to glaze-ink separation.

[0010] Specifically, inorganic pigments are the core coloring components in ceramic inks, and their content in ceramic inks is relatively high. However, they are prone to agglomeration or sedimentation in high solid content systems. In this application, 2 to 8 parts of sulfonic acid block polymers are added as dispersants. Such polymer molecules contain solvent-philic blocks and sulfonic acid adsorption blocks. Since inorganic pigments are generally metal oxides, the sulfonic acid adsorption blocks can be bound to the surface of the inorganic pigments through hydrogen bonds and surface coordination chelation. At the same time, the solvent-philic blocks can promote the dispersion of the inorganic pigments in the system. Therefore, the sulfonic acid block polymers can form a dual stable layer of charge and space steric hindrance on the surface of the inorganic pigments, thereby improving the dispersibility of the inorganic pigments and delaying particle sedimentation.

[0011] The inventors have found that the main means to solve the problem of glaze-ink separation in related technologies is to improve the quick-drying property of ceramic inks by using specific solvents, or to promote the penetration of inorganic pigments into the cosmetic soil layer by adding functional additives. There has been no optimization of dispersants in ceramic inks to reduce the risk of glaze-ink separation by improving the anchoring ability of inorganic pigments. It is understandable that the sulfonic acid block polymers in this application have stronger ionization, higher interfacial adsorption stability and better high-temperature pyrolysis residual anchoring ability compared to polycarboxylates and polyether-modified polymers as dispersants. They are suitable for the dispersion of inorganic pigments and the stable anchoring construction of pattern areas under the high-temperature sintering environment of ceramic inks. Their strong adsorption properties help to inhibit pigment migration and glaze-ink separation during the sintering process, thereby giving ceramic inks good storage stability and resistance to glaze-ink separation.

[0012] To enhance the anchoring effect of the inorganic pigment in synergistic effect with the sulfonic acid block polymer, 1–3 parts of polyvinyl alcohol grafted glycidyl methacrylate (PVA-g-GMA) are added to the ceramic ink. PVA-g-GMA contains multiple epoxy groups, which undergo thermally induced cross-linking reactions with the hydroxyl groups on the pigment surface and the hydroxyl groups on the surfaces of metal and non-metal oxides in the cosmetic layer and glaze layer during the initial heating process of sintering, thereby forming heat-cured anchoring points in the patterned area. This structure not only improves pattern adhesion but also inhibits interfacial slip during the vitrification flow of the inkjet pattern during the glaze layer, reducing the risk of glaze-ink separation. Furthermore, the PVA-g-GMA backbone is rich in hydroxyl groups and exhibits a certain degree of segmental flexibility. It can form a stable colloidal dispersion in highly polar ether-ester solvents (such as propylene glycol methyl ether acetate) and exhibits good interfacial wettability and stability. In the ceramic ink system, PVA-g-GMA can form a flexible coating on the surface of the pigment particles, enhancing interparticle repulsion and alleviating agglomeration caused by concentration or local shear. This structure can synergize with sulfonic acid block polymers to construct a dispersed-anchored composite interface: the sulfonic acid block provides strong adsorption capacity, and PVA-g-GMA provides flexible chain segment coating and interface viscoelastic buffering, thereby improving the stability and anti-sedimentation ability of the dispersed layer, thereby synergizing with the sulfonic acid block polymer to improve the storage stability of the ceramic ink.

[0013] It should be noted that although the sulfonic acid block polymer and PVA-g-GMA will gradually decompose during the sintering process, since they have formed carbonized structural residues, cross-linked network locking and interfacial condensation reactions with the glaze layer or makeup soil layer in the early heating stage, even if they are pyrolyzed, their structural traces can still build a stable anchoring environment in the pattern area, effectively limiting the migration, diffusion or interfacial separation of the pigment during the sintering process, thereby achieving improved pattern adhesion and post-firing conformality.

[0014] The organic solvent serves as a transfer medium and rheology control component. Its ratio of 50 to 70 parts ensures that the ink has suitable jetting rheology, stable physical dispersion state, and good wettability and drying properties. It can synergize with the above-mentioned sulfonic acid dispersant and PVA-g-GMA to maintain ink droplet formability and pattern stability.

[0015] In summary, the above components are collaboratively designed with clear division of labor and complementary functions, so that the ceramic ink provided in this application not only has excellent storage stability and resistance to glaze-ink separation during use, but also exhibits excellent pattern conformality and interface fusion ability with the glaze layer after sintering, thereby significantly improving the clarity of the ceramic surface pattern and having good industrial adaptability and promotion value.

[0016] In some embodiments, the sulfonic acid block polymer further contains epoxy groups.

[0017] In some of the aforementioned embodiments, the introduction of epoxy groups into the sulfonic acid block polymer not only retains its function as a highly effective dispersant but also further enables it to participate in cross-linking reactions during the sintering temperature rise phase. The inventors have discovered that the surface of pigment particles is typically rich in metal oxide hydroxyl functional groups, and that cosmetic and glaze layers often contain aluminosilicate structures such as kaolin, talc, and quartz. These components also contain a large number of structural or adsorptive hydroxyl groups. When an epoxy structure is introduced into the sulfonic acid block polymer, the epoxy group can undergo a ring-opening reaction at a temperature between 150 and 250°C, synergizing with PVA-g-GMA to form ether bonds or alcohol ether structures with the aforementioned hydroxyl groups, thereby constructing a microscale cross-linked anchoring network in situ in the pattern area. This network can lock the position of the pigment particles early in the sintering process. Even if the dispersant partially pyrolyzes during the later sintering stages, the anchoring structure it has formed can still retain the original arrangement of the pigment in the pattern area, significantly inhibiting the displacement, diffusion, and floating of the pigment caused by the vitrification flow of the glaze layer, thereby reducing the risk of glaze-ink separation, improving pattern conformality, and post-firing pattern boundary clarity. In addition, compared to dispersant structures containing only sulfonic acid groups, the sulfonic acid-epoxy bifunctional block polymer has stronger interfacial reactivity and can produce a synergistic reaction with PVA-g-GMA, constructing a complex cross-linking pathway in the multi-component system, further enhancing the structural stability and adhesion of the ceramic ink.

[0018] Therefore, the sulfonic acid block polymer after the introduction of epoxy groups not only realizes the integration of dispersion and anchoring functions, but also synergizes with the subsequent thermosetting cross-linking network and interfacial reaction structure to construct multiple anchoring pathways from the pigment surface to the inside of the pattern layer and then to the glaze interface, further enhancing the ceramic ink's ability to resist glaze-ink separation.

[0019] In some embodiments, the method for preparing the sulfonic acid block polymer comprises the following steps:

[0020] S1: methyl methacrylate, glycidyl methacrylate and 4-cyano-4-(phenylthioformylthio) valeric acid are subjected to a free radical polymerization reaction initiated by an initiator to obtain a P(MMA-co-GMA)-RAFT prepolymer;

[0021] S2: P(MMA-co-GMA)-RAFT prepolymer and sodium styrene sulfonate are subjected to free radical polymerization to obtain P(MMA-co-GMA)-b-PSSNa as a sulfonic acid block polymer.

[0022] In some of the aforementioned embodiments, the preparation method utilizes a RAFT controlled radical polymerization strategy to first synthesize a P(MMA-co-GMA) prepolymer with a precise functional monomer distribution. The prepolymer retains a RAFT chain transfer structure at its terminus, serving as an active initiation center for subsequent block polymerization. By copolymerizing glycidyl methacrylate (GMA) into the backbone, epoxy functional sites are introduced into the backbone structure, laying the structural foundation for thermal crosslinking and anchoring of the subsequent patterned regions. Subsequently, through a RAFT chain propagation mechanism, sodium styrene sulfonate (NaSS) is polymerized in a hydrophilic system to construct a sulfonic acid block, resulting in P(MMA-co-GMA)-b-PSSNa, which possesses an amphiphilic block structure and crosslinkable sites. In this structure, the PSSNa segment provides strong adsorption capacity and can produce hydrogen bond adsorption and coordination adsorption with the surface of metal oxide pigments, while the GMA segment in the P(MMA-co-GMA) main chain can participate in the heat-induced cross-linking reaction and chemically bond with other hydroxyl-containing structures in the pattern area, further enhancing the anchoring ability of the pigment; at the same time, the P(MMA-co-GMA) main chain has good compatibility with organic solvents, thereby improving the dispersibility of inorganic pigments in ceramic inks.

[0023] Unlike traditional single-chain structure dispersants, this block structure not only spatially separates the solvent-philic segment and the adsorption segment through segmented control, thereby improving the solubility and dispersion stability in the ink system, but also gives the dispersant molecules reactive and functional controllable properties during the heating process. It is a high-performance functional dispersant structure with adsorption, fluidity and cross-linking properties.

[0024] Therefore, the sulfonic acid block polymer obtained by this preparation method not only has good dispersion properties and interface adsorption capacity, but can also participate in the formation of the pattern anchoring network in the inkjet pattern area, constructing functional continuity from the solution phase to the heat treatment process, and further ensuring the structural stability and imaging consistency of the ceramic ink pattern.

[0025] In some embodiments, the method for preparing the sulfonic acid block polymer comprises the following steps:

[0026] S1: 10 parts of methyl methacrylate, 2-4 parts of glycidyl methacrylate, 0.1-0.5 parts of 4-cyano-4-(phenylthiocarbamoylthio)valeric acid, and 0.01-0.1 parts of azobisisobutyronitrile were dissolved in 30-50 parts of toluene, and the mixture was reacted at 60-70°C for 5-8 hours under a nitrogen atmosphere to obtain a P(MMA-co-GMA)-RAFT prepolymer;

[0027] S2: Take 10 parts of the P(MMA-co-GMA)-RAFT prepolymer, 5-10 parts of sodium styrene sulfonate, 0.01-0.1 parts of sodium persulfate, and 0.2-1 parts of sodium lauryl sulfate and disperse them in 50-80 parts of water. Under a nitrogen atmosphere, react at 60-70°C and pH 5.5-6.5 for 5-8 hours to obtain P(MMA-co-GMA)-b-PSSNa.

[0028] In some of the above embodiments, in step S1, the mass ratio of methyl methacrylate to glycidyl methacrylate is controlled at about 10:2~4, which helps to introduce a sufficient number of epoxy groups for the subsequent cross-linking reaction of the pattern area while maintaining the solvophilicity and flexibility of the polymer main chain, thereby improving the dispersion effect of the inorganic pigment.

[0029] The dosage of RAFT chain transfer agent (4-cyano-4-(phenylthiocarbamoylthio) valeric acid) is controlled at 0.1-0.5 parts, and the dosage of initiator (AIBN) is 0.01-0.1 parts. This ensures a stable polymerization rate and a controllable degree of polymerization, suppresses side reactions and excessively broad molecular weight distribution, and produces a prepolymer with a uniform molecular structure and a well-defined functional group distribution.

[0030] In step S2, the sodium styrene sulfonate dosage is controlled between 5 and 10 parts per million. This allows the formation of sulfonic acid blocks of a defined length under the guidance of the RAFT chain transfer agent, ensuring strong adsorption on the pigment surface while preventing molecular self-entanglement or reduced dispersibility due to excessively long chains. Sodium persulfate, used as an initiator, in an amount ranging from 0.01 to 0.1 parts per million helps ensure a stable free radical concentration, enabling efficient polymerization of the hydrophilic NaSS monomer under relatively mild polymerization conditions (60–70°C, pH 5.5–6.5), while avoiding crosslinking and hydrolysis side reactions. Sodium dodecyl sulfate, used as an emulsifier, forms a stable micellar environment in water, promoting uniform dispersion of the hydrophobic P(MMA-co-GMA)-RAFT prepolymer in the aqueous phase and ensuring that the NaSS polymer grows at its ends, thereby constructing a clear diblock structure.

[0031] Toluene, the reaction solvent, is used for the controlled polymerization of the backbone segments, fully dissolving MMA and GMA while maintaining a uniform reaction temperature and moderate viscosity, ensuring controllable RAFT polymerization. The aqueous emulsion system used for the polymerization of the PSSNa block facilitates the dissolution of NaSS and facilitates charge stabilization during polymerization. The entire process utilizes a two-stage reaction to construct the organophilic and hydrophilic adsorption segments, achieving structural-functional separation and unit control. The resulting block polymer offers excellent design freedom and functional programmability, making it suitable for ceramic inks requiring both dispersibility and thermal reactivity.

[0032] Therefore, by setting the process with the above-mentioned specific ratios and conditions, not only can a sulfonic acid block polymer with uniform structure, moderate segment length and clear functional groups be obtained, but also its dispersion stability and high-temperature pattern anchoring ability in the ceramic ink system can be improved.

[0033] In some embodiments, the PVA-g-GMA is prepared by the following method:

[0034] Polyvinyl alcohol and glycidyl methacrylate are reacted with Fenton's reagent to graft the hydroxyl groups of the polyvinyl alcohol segments with the double bonds of glycidyl methacrylate to obtain PVA-g-GMA.

[0035] In some of the aforementioned embodiments, the PVA-g-GMA is prepared by grafting polyvinyl alcohol (PVA) containing multiple hydroxyl structures with glycidyl methacrylate (GMA) having double bonds and epoxy groups under mild free radical conditions. The Fenton reagent (comprising hydrogen peroxide and ferrous ions) generates hydroxyl radicals, which attack the hydroxyl groups on the PVA backbone to form free radical active sites. The hydroxyl radicals then introduce the double bonds of GMA into the PVA backbone via free radical addition, while preserving the epoxy functional groups on the GMA molecules from hydrolysis or ring opening, thereby forming a PVA-g-GMA structure with a PVA backbone and epoxy groups on the side chains.

[0036] Among them, the PVA main chain has good flexibility, film-forming properties and polarity, which helps it form a stable colloidal dispersion in polar organic solvents (such as ether ester solvents); the grafted GMA structure retains unreacted epoxy groups, which can undergo ring-opening etherification or esterification reactions with various hydroxyl groups present in the inkjet pattern area (including surface hydroxyl groups of inorganic pigments, kaolin structure hydroxyl groups in cosmetic soil, surface hydroxyl groups of metal oxides in glazes, etc.) during the early heating process of ceramic sintering, forming an in situ cross-linked anchoring network in the pattern area.

[0037] Furthermore, the residual hydroxyl groups on the PVA chain segments can also synergistically react with the epoxy groups in the sulfonic acid block polymer, further strengthening the anchoring network structure. This cross-linked structure exerts a dual physical and chemical restraint on the pigment particles in the inkjet pattern, effectively reducing interfacial drag, boundary diffusion, or floating of the pigment during the vitrification flow of the glaze layer, thereby significantly inhibiting glaze-ink separation and improving pattern adhesion and clarity.

[0038] Therefore, the PVA-g-GMA prepared by the above method not only has good colloidal dispersibility and epoxy reaction activity, but also can cooperate with the sulfonic acid block polymer to construct a thermally induced anchoring structure in the pattern area, while improving the storage stability of ceramic ink and effectively enhancing its ability to resist glaze ink separation.

[0039] In some embodiments, the PVA-g-GMA is prepared by the following method:

[0040] 10 parts of polyvinyl alcohol with a weight-average molecular weight of 30,000-50,000 was dissolved in 80-150 parts of water. An ethanol solution containing 0.5-2 parts of glycidyl methacrylate was added dropwise to the above solution at 50-60°C. Then, 0.01-0.1 parts of hydrogen peroxide and 0.005-0.05 parts of ferrous sulfate were added. The mixture was reacted at 50-60°C and pH 4-5 under a nitrogen atmosphere for 2-4 hours to obtain PVA-g-GMA.

[0041] In some of the above embodiments, the weight of polyvinyl alcohol is 10 parts, and the molecular weight of the PVA used is controlled to be between 30,000 and 50,000, ensuring good ink dispersion compatibility while also providing a certain degree of molecular chain flexibility, enabling it to collaborate with the dispersant to stabilize the colorant distribution in the ink system. The amount of dissolved water is controlled between 80 and 150 parts, which can adjust the viscosity of the system, maintain uniform heat transfer and a stable solution state during the reaction, and facilitate the control of the GMA dropwise addition reaction. The amount of GMA is 0.5 to 2 parts, and the degree of grafting with the PVA chain segment is controlled by dropwise addition. Within this range, a sufficient number of epoxy groups are introduced for the subsequent crosslinking reaction while avoiding the problem of excessive introduction leading to decreased solution phase stability before crosslinking. The reaction temperature is maintained between 50 and 60°C, and the reaction pH is maintained between 4 and 5. This allows the Fenton reagent to generate hydroxyl radicals to initiate the reaction, while also reducing the hydrolysis of epoxy groups under alkaline conditions, reducing GMA self-polymerization, and inhibiting the degradation of the PVA backbone.

[0042] In the PVA-g-GMA produced under these reaction conditions, GMA can be grafted onto the PVA segments via free radical addition, maintaining the hydroxyl structure and flexibility of the main chain and epoxy groups on the side chains. In ceramic ink systems, this polymer not only synergizes with the sulfonic acid block polymer to enhance system stability, but also acts as a crosslinker to form a heat-induced anchoring network in the patterned area, thereby enhancing the pattern's boundary retention and post-firing adhesion.

[0043] Therefore, the above preparation parameters were optimized to make the obtained PVA-g-GMA structure stable and have clear performance, which is suitable for constructing a cross-linked anchoring network in the pattern area and improving the pattern's anti-drift ability and imaging clarity during the ceramic sintering process.

[0044] In some embodiments, the inorganic pigment includes a modified pigment obtained by modifying a metal oxide pigment using an epoxy silane coupling agent.

[0045] In some of the aforementioned embodiments, the modified pigment is based on a metal oxide pigment (such as copper chrome black, iron oxide red, and zirconium yellow). Surface modification with an epoxysilane coupling agent introduces functional groups reactive with dispersants or PVA-g-GMA. Upon hydrolysis, the silane groups in the epoxysilane coupling agent undergo condensation reactions with the pigment's surface hydroxyl groups or adsorbed water, forming stable Si-O-Me bonds (where Me represents the metal oxide surface site). The epoxy groups then serve as potential crosslinking sites in the subsequent system. This modification eliminates the inert inorganic particle surface and forms a "functionalized shell" with interfacial reactivity and enhanced polymer affinity. This shell structure not only helps enhance the adsorption match between the pigment and the sulfonic acid block polymer, improving the dispersion uniformity and stability of the pigment in the system, but also undergoes an epoxy-hydroxyl cross-linking reaction with hydroxyl-containing substances in the system during the sintering temperature rise phase, thereby forming an anchoring structure of the pigment-organic layer-interface network. The presence of the epoxysilane coating also serves to establish an interfacial compatibility bridge between the pigment and the glazing layer. On the one hand, it can undergo a condensation reaction with the hydroxyl structures in the cosmetic soil layer, and on the other hand, it can fuse with the applied transparent glaze during the vitrification process, improving the interfacial adhesion of the pattern area and reducing the probability of floating color and peeling of the pattern after firing.

[0046] Therefore, by using epoxy silane coupling agent to modify the surface of metal oxide pigments, the dispersion stability, interfacial reaction activity and structural fusion ability between the pattern area and the glaze layer of the pigment can be significantly improved. In the ceramic ink system provided in this application, it synergizes with the dispersant and PVA-g-GMA to effectively enhance the pattern anchoring effect, improve the pattern imaging clarity and post-firing adhesion strength.

[0047] In some embodiments, the preparation method of the modified colorant includes the following steps: dispersing 30 parts of metal oxide colorant and 1 to 5 parts of γ-glycidyloxypropyltrimethoxysilane in a mixed solvent of 70 to 100 parts of ethanol and water, reacting at 40 to 60° C. and pH 4.5 to 5.5 for 2 to 4 hours to obtain the modified colorant.

[0048] In some of the aforementioned embodiments, γ-glycidyloxypropyltrimethoxysilane undergoes partial hydrolysis in a water-alcohol system, generating an intermediate with Si-OH activity. This intermediate can undergo a condensation reaction with hydroxyl groups or hydration layers on the surface of metal oxide pigments, forming stable silanol bridges. The unreacted epoxy groups within the γ-glycidyloxypropyltrimethoxysilane structure remain stably on the pigment surface, allowing them to participate in chemical reactions with PVA-g-GMA or hydroxyl-containing molecules in subsequent ceramic ink systems. This modification method offers gentle operation, high coupling efficiency, and strong adaptability, making it suitable for a variety of metal oxide inorganic pigments. The resulting pigment powder surface exhibits excellent dispersion affinity and thermally induced reactivity, making it suitable for use in ceramic inkjet printing ink systems requiring high pattern anchoring performance.

[0049] In some embodiments, the particle size D100 of the inorganic pigment is 0.5 to 1 μm. Based on the above embodiment, it helps to reduce the risk of sedimentation, aggregation or nozzle clogging caused by large particles. In the pre-high-temperature sintering stage, a moderate particle size range can also enhance the coating synergy between the inorganic pigment and the sulfonic acid block polymer and PVA-g-GMA, so that the pigment forms a dense distribution in the pattern area while having good interfacial reactivity and structural retention. As an example, the particle size D100 of the inorganic pigment in one embodiment of the present application is 0.6 μm.

[0050] In some embodiments, the organic solvent includes at least one of methyl propionate, dipropylene glycol butyl ether, propylene glycol methyl ether acetate, and isopropyl alcohol. Based on the above embodiments, these solvents have both moderate volatility and good polarity compatibility, forming a uniform dissolution system with the sulfonic acid block dispersant, PVA-g-GMA, and modified colorant. For example, propylene glycol methyl ether acetate is used as the organic solvent in one embodiment of the present application.

[0051] In some embodiments, the highly stable ceramic ink further includes 1-3 parts of a defoaming agent. Based on the above embodiments, the introduction of a defoaming agent can effectively suppress microbubbles formed by dispersant structure, pigment surface activity, or shear disturbances, thereby preventing defects such as ink breakage and ink skewing caused by bubble accumulation in the ink nozzle. For example, tributyl phosphate is used as the defoaming agent in one embodiment of the present application.

[0052] In a second aspect, the present application provides a method for preparing a highly stable ceramic ink, comprising: providing components of the highly stable ceramic ink according to any embodiment of the first aspect; and mixing the components to obtain a highly stable ceramic ink.

[0053] According to the present application, the preparation method has a simple operational process and mild process conditions, making it suitable for industrial continuous production. By sequentially mixing and dispersing the inorganic pigment, sulfonic acid block polymer, PVA-g-GMA, organic solvent, and optional defoaming agent in a proportionate weight ratio, not only can the pigment particles be efficiently coated and stably suspended, but a multiphase synergistic structure can also be initially established within the system during the mixing process, providing a good interfacial foundation for the subsequent anchoring reaction in the patterned area.

[0054] In this method, the components can be added sequentially at room or low temperatures, achieving uniform dispersion without the need for high shear or high temperatures. This helps preserve the integrity of the epoxy groups and dispersant structure, avoiding premature reaction and potential functional loss. The resulting ceramic ink exhibits excellent storage stability, uniform dispersion, and sprayability, making it suitable for currently widely used industrial inkjet printing systems. It is particularly well-suited for printing ceramic tile layers where high pattern adhesion is required and the risk of glaze-ink separation is high.

[0055] In a third aspect, the present application provides a ceramic tile comprising: a brick layer, a cosmetic layer, an inkjet printed layer and a glaze layer, wherein the inkjet printed layer is obtained by inkjet printing the highly stable ceramic ink according to any embodiment of the first aspect or the highly stable ceramic ink prepared by the method described in any embodiment of the second aspect onto the cosmetic layer and sintering the inkjet printed layer.

[0056] According to the present application, by applying the highly stable ceramic ink to a ceramic tile structure, the resulting inkjet-printed layer exhibits excellent pattern imaging accuracy, adhesion, and sintering stability. The sulfonic acid block polymer in the ink firmly adsorbs onto the surface of the metal oxide pigment during the early stages of sintering, preventing pigment particle migration, agglomeration, or floating, thereby maintaining clear pattern boundaries. During heating, the PVA-g-GMA undergoes a thermally induced cross-linking reaction with the hydroxyl functional groups on the cosmetic layer, glaze layer, or pigment surface, further establishing a localized anchoring structure within the patterned area and inhibiting glaze-ink separation.

[0057] Furthermore, after glazing and firing, the inkjet-printed layer in the tile forms a well-integrated interface with the polished glaze layer, ensuring the integrity and transparency of the glaze surface while also preventing blurring or loss of adhesion caused by flow deformation during the high-temperature vitrification phase. This results in long-term pattern stability, consistent color, and high visual resolution after firing. This tile structure is particularly suitable for high-end digital inkjet ceramics, such as those creating highly realistic patterns like simulated stone and wood grain patterns and gradient layers.

[0058] Compared with the prior art, the present invention has the following advantages:

[0059] The use of sulfonic acid block polymers and PVA-g-GMA to synergistically construct a highly stable ceramic ink formula can significantly improve the ink's dispersion stability, pattern adhesion and post-firing imaging quality, effectively reduce the risk of glaze-ink separation, and is suitable for high-resolution inkjet printing applications of complex patterns. It has good industrial practicality and promotion value. DETAILED DESCRIPTION

[0060] The various embodiments or implementation schemes in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments.

[0061] Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples" means that a specific feature, structure, material, or characteristic described in conjunction with an embodiment or example is included in at least one embodiment or example of the present application. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0062] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of such features. Throughout the description of this application, "plurality" means at least two, for example, two, three, etc., unless otherwise specifically defined.

[0063] In the description of this specification, unless otherwise specified, "parts" refer to "parts by mass".

[0064] Below, the embodiment of the present application is described. The embodiment described below is exemplary and is only used to explain the present application, and is not to be construed as limiting the present application. Where specific techniques or conditions are not specified in the embodiments, the techniques or conditions described in the literature in this area or the product specifications are used. Reagents or instruments used that do not specify the manufacturer are conventional products that can be obtained commercially.

[0065] Polyvinyl alcohol, weight average molecular weight of 40,000, alcoholysis degree ≥98%;

[0066] Copper chrome black, D100 is 0.6μm.

[0067] Preparation Example 1

[0068] 10 parts of methyl methacrylate, 2 parts of glycidyl methacrylate, 0.3 parts of 4-cyano-4-(phenylthiocarbamoylthio)valeric acid, and 0.05 parts of azobisisobutyronitrile were dissolved in 40 parts of toluene and reacted in an oil bath at 65°C under a nitrogen atmosphere for 6 hours. After the reaction, the reaction solution was poured into an excess of anhydrous methanol for precipitation, filtered, washed twice with ethanol, and dried in vacuo at 50°C to obtain a P(MMA-co-GMA)-RAFT prepolymer.

[0069] Ten parts of a P(MMA-co-GMA)-RAFT prepolymer, six parts of sodium styrene sulfonate, 0.04 parts of sodium persulfate, and 0.8 parts of sodium lauryl sulfate were dispersed in 60 parts of water. The pH was adjusted to 6 and ultrasonically treated to form an emulsion. The mixture was then reacted in an oil bath at 70°C under a nitrogen atmosphere for 6 hours. After the reaction was completed, the mixture was cooled to room temperature and precipitated by adding anhydrous ethanol. The product was recovered by centrifugation, washed three times with ethanol, and dried under vacuum at 50°C to obtain P(MMA-co-GMA)-b-PSSNa-1.

[0070] Preparation Example 2

[0071] 10 parts of methyl methacrylate, 4 parts of glycidyl methacrylate, 0.3 parts of 4-cyano-4-(phenylthiocarbamoylthio)valeric acid, and 0.05 parts of azobisisobutyronitrile were dissolved in 40 parts of toluene and reacted in an oil bath at 65°C under a nitrogen atmosphere for 6 hours. After the reaction, the reaction solution was poured into an excess of anhydrous methanol for precipitation, filtered, washed twice with ethanol, and dried in a vacuum at 50°C to obtain a P(MMA-co-GMA)-RAFT prepolymer.

[0072] Ten parts of a P(MMA-co-GMA)-RAFT prepolymer, six parts of sodium styrene sulfonate, 0.04 parts of sodium persulfate, and 0.8 parts of sodium lauryl sulfate were dispersed in 60 parts of water. The pH was adjusted to 6 and ultrasonically treated to form an emulsion. The mixture was then reacted in an oil bath at 70°C under a nitrogen atmosphere for 6 hours. After the reaction was completed, the mixture was cooled to room temperature and precipitated by adding anhydrous ethanol. The product was recovered by centrifugation, washed three times with ethanol, and dried under vacuum at 50°C to obtain P(MMA-co-GMA)-b-PSSNa-2.

[0073] Preparation Example 3

[0074] 10 parts of methyl methacrylate, 5 parts of glycidyl methacrylate, 0.3 parts of 4-cyano-4-(phenylthiocarbamoylthio)valeric acid, and 0.05 parts of azobisisobutyronitrile were dissolved in 40 parts of toluene and reacted in an oil bath at 65°C under a nitrogen atmosphere for 6 hours. After the reaction, the reaction solution was poured into an excess of anhydrous methanol for precipitation, filtered, washed twice with ethanol, and dried in vacuo at 50°C to obtain a P(MMA-co-GMA)-RAFT prepolymer.

[0075] Ten parts of the aforementioned P(MMA-co-GMA)-RAFT prepolymer, 6 parts of sodium styrene sulfonate, 0.04 parts of sodium persulfate, and 0.8 parts of sodium lauryl sulfate were dispersed in 60 parts of water. The pH was adjusted to 6 and ultrasonically treated to form an emulsion. The mixture was then reacted in an oil bath at 70°C under a nitrogen atmosphere for 6 hours. After the reaction was completed, the mixture was cooled to room temperature and precipitated by adding anhydrous ethanol. The product was recovered by centrifugation, washed three times with ethanol, and dried under vacuum at 50°C to obtain P(MMA-co-GMA)-b-PSSNa-3.

[0076] Preparation Example 4

[0077] 12 parts of methyl methacrylate, 0.3 parts of 4-cyano-4-(phenylthiocarbamoylthio)valeric acid, and 0.05 parts of azobisisobutyronitrile were dissolved in 40 parts of toluene and reacted in an oil bath at 65°C under a nitrogen atmosphere for 6 hours. After the reaction, the reaction solution was poured into an excess of anhydrous methanol for precipitation, filtered, washed twice with ethanol, and dried in a vacuum at 50°C to obtain a PMMA-RAFT prepolymer.

[0078] Ten parts of the PMMA-RAFT prepolymer, 6 parts of sodium styrene sulfonate, 0.04 parts of sodium persulfate, and 0.8 parts of sodium lauryl sulfate were dispersed in 60 parts of water. The pH was adjusted to 6 and ultrasonically treated to form an emulsion. The mixture was then reacted in an oil bath at 70°C under a nitrogen atmosphere for 6 hours. After the reaction was completed, the mixture was cooled to room temperature and precipitated by adding anhydrous ethanol. The product was recovered by centrifugation, washed three times with ethanol, and dried under vacuum at 50°C to obtain PMMA-b-PSSNa.

[0079] Preparation Example 5

[0080] 10 parts of polyvinyl alcohol were added to 120 parts of water, heated in a water bath at 90°C with stirring until completely dissolved, and cooled to 55°C. 1 part of glycidyl methacrylate was dissolved in 15 parts of ethanol to obtain an ethanol solution of glycidyl methacrylate. The above-mentioned ethanol solution of glycidyl methacrylate was added dropwise under stirring, and the pH was adjusted to 4.5. An aqueous solution containing 0.05 parts of hydrogen peroxide and 0.025 parts of ferrous sulfate was added, and the mixture was reacted at 55°C under a nitrogen atmosphere for 2 hours. Excess cold ethanol was added to precipitate the product, which was recovered by centrifugation, washed three times with ethanol, and dried in vacuo at 50°C to obtain PVA-g-GMA-1.

[0081] Preparation Example 6

[0082] 10 parts of polyvinyl alcohol were added to 120 parts of water, heated in a water bath at 90°C with stirring until completely dissolved, and cooled to 55°C. 4 parts of glycidyl methacrylate were dissolved in 15 parts of ethanol to obtain an ethanol solution of glycidyl methacrylate. The above-mentioned ethanol solution of glycidyl methacrylate was added dropwise under stirring, and the pH was adjusted to 4.5. An aqueous solution containing 0.05 parts of hydrogen peroxide and 0.025 parts of ferrous sulfate was added, and the mixture was reacted at 55°C under a nitrogen atmosphere for 2 hours. Excess cold ethanol was added to precipitate the product, which was recovered by centrifugation, washed three times with ethanol, and dried in vacuo at 50°C to obtain PVA-g-GMA-2.

[0083] Preparation Example 7

[0084] 30 parts of copper chrome black were dispersed in 90 parts of a mixed solution of ethanol and water in a volume ratio of 2:1, and then 3 parts of γ-glycidyloxypropyltrimethoxysilane were added. The pH was adjusted to 5, and the system was heated to 50°C. The reaction was carried out under constant temperature stirring for 3 hours. After the reaction was completed, the product was collected by centrifugation, washed twice with ethanol, and vacuum dried at 50°C to obtain modified copper chrome black.

[0085] Comparative Preparation Example 1

[0086] 10 parts of methyl methacrylate, 2 parts of glycidyl methacrylate, 0.3 parts of 4-cyano-4-(phenylthiocarbamoylthio)valeric acid, and 0.05 parts of azobisisobutyronitrile were dissolved in 40 parts of toluene and reacted in an oil bath at 65°C under a nitrogen atmosphere for 6 hours. After the reaction, the reaction solution was poured into an excess of anhydrous methanol for precipitation, filtered, washed twice with ethanol, and dried in vacuo at 50°C to obtain a P(MMA-co-GMA)-RAFT prepolymer.

[0087] Ten parts of the aforementioned P(MMA-co-GMA)-RAFT prepolymer, 6 parts of methacrylic acid, 0.04 parts of sodium persulfate, and 0.8 parts of sodium lauryl sulfate were dispersed in 60 parts of water. The pH was adjusted to 6 and ultrasonically treated to form an emulsion. The emulsion was then reacted in an oil bath at 70°C under a nitrogen atmosphere for 6 hours. After the reaction was completed, the mixture was cooled to room temperature and precipitated by adding anhydrous ethanol. The product was recovered by centrifugation, washed three times with ethanol, and dried under vacuum at 50°C to obtain P(MMA-co-GMA)-b-PMAA.

[0088] Example 1

[0089] Preparation of highly stable ceramic ink:

[0090] 5 parts of P(MMA-co-GMA)-b-PSSNa-1 and 2 parts of PVA-g-GMA-1 are dispersed in 40 parts of propylene glycol methyl ether acetate, and then 30 parts of modified copper chromium black and 2 parts of tributyl phosphate are added to obtain a mixture. The mixture is added to a spherical ink tank, and zirconium oxide grinding beads with a diameter of 0.3 mm are added. The mixture is ground at 500 rpm for 2 hours to mix evenly. After passing through a 5 μm stainless steel filter, 20 parts of propylene glycol methyl ether acetate are added to obtain a highly stable ceramic ink.

[0091] Example 2

[0092] Preparation of highly stable ceramic ink:

[0093] The process is substantially the same as Example 1, except that P(MMA-co-GMA)-b-PSSNa-2 is used instead of P(MMA-co-GMA)-b-PSSNa-1.

[0094] Example 3

[0095] Preparation of highly stable ceramic ink:

[0096] The process is substantially the same as Example 1, except that P(MMA-co-GMA)-b-PSSNa-3 is used instead of P(MMA-co-GMA)-b-PSSNa-1.

[0097] Example 4

[0098] Preparation of highly stable ceramic ink:

[0099] The process is substantially the same as Example 1, except that PMMA-b-PSSNa is used instead of P(MMA-co-GMA)-b-PSSNa-1.

[0100] Example 5

[0101] Preparation of highly stable ceramic ink:

[0102] The process is substantially the same as Example 1, except that PVA-g-GMA-2 is used instead of PVA-g-GMA-1.

[0103] Example 6

[0104] Preparation of highly stable ceramic ink:

[0105] The process is substantially the same as Example 1, except that unmodified copper chrome black is used instead of modified copper chrome black.

[0106] Comparative Example 1

[0107] Preparation of highly stable ceramic ink:

[0108] The process is substantially the same as Example 1, except that P(MMA-co-GMA)-b-PMAA is used instead of P(MMA-co-GMA)-b-PSSNa-1.

[0109] Comparative Example 2

[0110] Preparation of highly stable ceramic ink:

[0111] 7 parts of P(MMA-co-GMA)-b-PSSNa-1 were dispersed in 40 parts of propylene glycol methyl ether acetate, and then 30 parts of modified copper chromium black and 2 parts of tributyl phosphate were added to obtain a mixture. The mixture was added to a spherical ink tank, and zirconia grinding beads with a diameter of 0.3 mm were added. The mixture was ground at 500 rpm for 2 hours to mix evenly. After passing through a 5 μm stainless steel filter, 20 parts of propylene glycol methyl ether acetate were added to obtain a highly stable ceramic ink.

[0112] Comparative Example 3

[0113] Preparation of highly stable ceramic ink:

[0114] 7 parts of PVA-g-GMA-1 were dispersed in 40 parts of propylene glycol methyl ether acetate, and then 30 parts of modified copper chromium black and 2 parts of tributyl phosphate were added to obtain a mixture. The mixture was added to a spherical ink tank, and zirconium oxide grinding beads with a diameter of 0.3 mm were added. The mixture was ground at 500 rpm for 2 hours to mix evenly. After passing through a 5 μm stainless steel filter, 20 parts of propylene glycol methyl ether acetate were added to obtain a highly stable ceramic ink.

[0115] Test section

[0116] Stability Test: The highly stable ceramic inks obtained in each example and comparative example were stored at 25°C for 30, 60, and 120 days, and then observed for delamination and precipitation. The highly stable ceramic inks after storage for 30, 60, and 120 days were then tested for printing using an inkjet printer. Printing was continued for 5 hours, and the inkjet printer was observed for inkjet clogging. The results are shown in Table 1.

[0117] Anti-glaze ink separation test: The highly stable ceramic inks obtained in each example and comparative example were printed using a digital inkjet printer onto ceramic tiles with a surface coating. The pattern was a standard pure black block (50 mm × 50 mm). After printing, the ink was dried and glaze was applied. The glaze specific gravity was 1.20 g / mL and the glaze amount was 300 g / m. 2 Then, the temperature was raised to 250°C at 5°C / min in a box-type resistance furnace, and then raised to 1200°C at 10°C / min, and fired for 30 minutes to obtain tile samples.

[0118] Preparation of glaze slurry: Accurately weigh 100 parts of glaze (formula: 49 parts of albite, 6.5 parts of limestone, 10.7 parts of wollastonite, 5.5 parts of dolomite, 6.4 parts of zinc oxide, 3.8 parts of aluminum oxide, 7 parts of white corundum, 4.5 parts of quartz powder, 4.6 parts of kaolin, and 2 parts of frit), 0.1 part of carboxymethyl cellulose, 0.2 part of sodium hexametaphosphate, 100 parts of water, and 300 parts of ball stone, and put them into a clean ball mill. Place the ball mill in a fast ball mill and ball mill for three minutes to obtain glaze slurry.

[0119] A camera was used to acquire pattern images under a fixed light source and fixed angle. The images were converted to grayscale using ImageJ software. A grayscale threshold with an L value of >50 was designed to identify “bright spots,” “floating colors,” and “empty glaze areas.” The areas of these areas were counted as A1, and the overall projection area of ​​the pattern was A0. The proportion of the glaze-ink separation area was calculated as A1 / A0×100%. The results are shown in Table 2.

[0120] Table 1

[0121]

[0122] Table 2

[0123]

[0124] According to Table 1 and Table 2, the storage stability, printing continuity and glaze-ink separation area ratio of the ceramic ink obtained in each embodiment are better than those of the comparative examples, indicating that the ceramic ink provided by the present application has good storage stability and resistance to glaze-ink separation. Specifically, in comparative example 1, a PMAA block dispersant without a sulfonic acid anchoring structure is used, resulting in poor dispersant adsorption stability, stratification during the storage period, discontinuous printing performance, and an increase in the glaze-ink separation area ratio to 17.4%; in comparative example 2, a single high-content dispersant is used but PVA-g-GMA is not added, and there are also problems of stratification and boundary loss, with a glaze-ink separation area ratio as high as 19.6%; in comparative example 3, only PVA-g-GMA is added, which is not tightly adsorbed with the colorant and is dispersed only through steric hindrance. Its stability is poor, the printing performance is discontinuous, the glaze-ink separation area ratio is discontinuous, and the resistance to glaze-ink separation is very poor.

[0125] Comparing Examples 1 to 4, it can be seen that in Examples 1 and 2, when suitable P(MMA-co-GMA)-b-PSSNa is used in conjunction with PVA-g-GMA and matched with a surface-modified inorganic pigment, the ceramic ink prepared still has no stratification or precipitation after storage for 120 days, and there is no clogging phenomenon during continuous printing for 5 hours. The inkjet pattern and the glaze layer have good fusion, and the glaze-ink separation area accounts for as low as 2.1% and 1.9%. The pattern has high clarity and strong adhesion. In Example 3, when the proportion of GMA in the functional dispersant P(MMA-co-GMA)-b-PSSNa is further increased, although the short-term stability is acceptable, long-term storage has problems. There was no delamination phenomenon, and the nozzle was clogged after 120 days of printing. At the same time, the proportion of glaze-ink separation area increased to 6.2%, indicating that the excessive introduction of epoxy groups would affect the reaction uniformity and thermal anchoring effect; in Example 4, when the functional dispersant used PMMA-b-PSSNa and did not contain GMA, although its stability was high and no clogging occurred, the sintered pattern had obvious floating color, and the proportion of glaze-ink separation area increased to 9.8%; this shows that controlling the appropriate GMA content in the P (MMA-co-GMA) segment in the functional dispersant is helpful to achieve a balance between maintaining solvent affinity and thermal reactivity, and can improve the stability of the ceramic ink and its ability to resist glaze-ink separation.

[0126] By comparing Examples 1 and 5, it can be seen that the epoxy group content in PVA-g-GMA in Example 5 is relatively high, which will affect the long-term stability and resistance to glaze-ink separation of the ceramic ink. The reason may be that during the sintering temperature increase process, the high-density epoxy groups are prone to premature self-crosslinking or uneven reaction with the colorant / base layer, forming local over-crosslinking in the pattern area, causing the structure of the local area of ​​the pattern to become rigid and lose its soft adhesion ability. On the contrary, it is more likely to be pushed or floated during the vitrification flow stage of the glaze layer, resulting in typical glaze-ink separation phenomena such as floating color at the pattern boundary and edge diffusion. This shows that controlling the epoxy group content in PVA-g-GMA can improve the stability and resistance to glaze-ink separation of the ceramic ink.

[0127] By comparing Examples 1 and 6, it can be seen that the colorant in Example 6 uses unmodified copper chromium black, and its resistance to glaze ink separation is poorer than that in Example 1. The reason may be that although the sulfonic acid block polymer adsorbed on the surface of the inorganic colorant can participate in subsequent thermal cross-linking through the grafted epoxy group, the unmodified copper chromium black lacks sufficient interface fixing points for effective anchoring. During the sintering process, it is difficult to form a uniform and stable cross-linked network structure inside the pattern area, the anchoring ability of the colorant particles is weak, and boundary migration and floating color phenomena occur. This shows that further epoxidation modification of the colorant can improve the resistance of the ceramic ink to glaze ink separation.

[0128] In summary, this application significantly improves the structural stability and anti-glaze ink separation performance of ceramic ink during the entire process of storage, printing and sintering through the synergistic optimization of three aspects: dispersant molecular structure design, cross-linking reaction ability regulation and pigment interface synergistic modification.

[0129] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some or all of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A highly stable ceramic ink, characterized in that: The composition comprises the following components in parts by weight: 30 parts of inorganic pigment, 2-8 parts of sulfonic acid block polymer, 1-3 parts of polyvinyl alcohol grafted glycidyl methacrylate, 50-70 parts of organic solvent; The preparation method of the sulfonic acid block polymer comprises the following steps: S1: 10 parts of methyl methacrylate, 2-4 parts of glycidyl methacrylate and 0.1-0.5 parts of 4-cyano-4-(phenylthioformylthio) valeric acid are subjected to a free radical polymerization reaction under the initiation of an initiator to obtain a P(MMA-co-GMA)-RAFT prepolymer; S2: 10 parts of P(MMA-co-GMA)-RAFT prepolymer and 5-10 parts of sodium styrene sulfonate are subjected to free radical polymerization under the initiation of an initiator to obtain P(MMA-co-GMA)-b-PSSNa as a sulfonic acid block polymer; The polyvinyl alcohol grafted glycidyl methacrylate is prepared by the following method: Dissolve 10 parts of polyvinyl alcohol having a weight-average molecular weight of 30,000 to 50,000 in 80 to 150 parts of water, add dropwise 0.5 to 2 parts of an ethanol solution containing glycidyl methacrylate to the solution at 50 to 60° C., then add 0.01 to 0.1 parts of hydrogen peroxide and 0.005 to 0.05 parts of ferrous sulfate, and react under a nitrogen atmosphere at 50 to 60° C. and a pH of 4 to 5 for 2 to 4 hours to obtain polyvinyl alcohol grafted glycidyl methacrylate; The inorganic pigment includes a modified pigment obtained by modifying a metal oxide pigment using an epoxy silane coupling agent.

2. The highly stable ceramic ink according to claim 1, characterized in that The preparation method of the sulfonic acid block polymer comprises the following steps: S1: 10 parts of methyl methacrylate, 2-4 parts of glycidyl methacrylate, 0.1-0.5 parts of 4-cyano-4-(phenylthiocarbamoylthio)valeric acid, and 0.01-0.1 parts of azobisisobutyronitrile were dissolved in 30-50 parts of toluene, and the mixture was reacted at 60-70°C for 5-8 hours under a nitrogen atmosphere to obtain a P(MMA-co-GMA)-RAFT prepolymer; S2: Take 10 parts of the P(MMA-co-GMA)-RAFT prepolymer, 5-10 parts of sodium styrene sulfonate, 0.01-0.1 parts of sodium persulfate, and 0.2-1 parts of sodium lauryl sulfate and disperse them in 50-80 parts of water. Under a nitrogen atmosphere, react at 60-70°C and pH 5.5-6.5 for 5-8 hours to obtain P(MMA-co-GMA)-b-PSSNa.

3. The highly stable ceramic ink according to claim 1 or 2, characterized in that: The highly stable ceramic ink satisfies at least one of the following conditions: 1) The particle size D100 of the inorganic pigment is 0.5-1 μm; 2) The organic solvent includes at least one of methyl propionate, dipropylene glycol butyl ether, propylene glycol methyl ether acetate, and isopropyl alcohol; 3) The highly stable ceramic ink further comprises: 1 to 3 parts of a defoaming agent.

4. A method for preparing a highly stable ceramic ink, characterized in that: include: Providing components of the highly stable ceramic ink according to any one of claims 1 to 3; The components are mixed to obtain a highly stable ceramic ink.

5. A ceramic tile, characterized in that: include: A brick layer, a cosmetic layer, an inkjet-printed layer, and a glaze layer, wherein the inkjet-printed layer is obtained by inkjet printing the highly stable ceramic ink according to any one of claims 1 to 3 or the highly stable ceramic ink prepared according to the method of claim 4 onto the cosmetic layer and sintering the inkjet-printed layer.

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