Iridescence antibacterial ceramic tile and preparation method thereof

Abstract

The present application relates to the technical field of building ceramics, and particularly relates to a color-changing antibacterial ceramic tile and a preparation method thereof, comprising the following steps: A, preparing a body layer; B, applying color-changing antibacterial glaze on the surface of the body layer to obtain a color-changing antibacterial glaze layer; C, drying and then entering a kiln for calcination, and polishing to obtain the color-changing antibacterial ceramic tile. The color-changing antibacterial ceramic tile and the preparation method thereof ensure that the obtained color-changing antibacterial ceramic tile has antibacterial property and color-changing effect, and also has high wear resistance and transparency, so as to meet the actual use requirement.

Description

Technical Field

[0001] This invention relates to the field of building ceramics technology, and in particular to a multicolored antibacterial ceramic tile and its preparation method. Background Technology

[0002] With social development and the improvement of people's living standards, people have increasingly higher requirements for the quality of life and greater awareness of environmental protection, making antibacterial materials increasingly valued. Iridescent antibacterial ceramic tiles are a new type of functional material that protects the environment. While maintaining the original functionality and decorative effect of ceramic tile products, they add disinfection, sterilization, and chemical degradation functions, and are widely used in hygiene, medical, residential, civil, and industrial construction industries.

[0003] Existing iridescent antibacterial ceramic tiles are typically made by adding silver-based antibacterial agents, such as silver oxide, to the glaze, followed by high-temperature sintering. However, during the high-temperature calcination process, because the decomposition temperature of silver-based antibacterial agents such as silver oxide is usually below 500℃ and their heat resistance is poor, they decompose before a glassy phase that reacts with them forms in the system, generating elemental silver and oxygen (a redox reaction with virtually no antibacterial activity, where Ag...) + Reduced to Ag, O 2- (It is oxidized to O2), which weakens or even eliminates the antibacterial properties of the glaze, resulting in poor antibacterial effect of the prepared iridescent antibacterial tiles, making it difficult to achieve the ideal antibacterial effect in practical applications.

[0004] To address the aforementioned shortcomings, the industry has developed a method of using inorganic materials as a coating layer to coat silver-based antibacterial agents such as silver oxide to obtain high-temperature resistant antibacterial agents, thereby improving the high-temperature resistance of silver-based antibacterial agents. However, the aforementioned high-temperature resistant antibacterial agents have the following shortcomings: (1) Their coating method is only physical coating, which prevents the silver ions in the antibacterial agent silver oxide from being chemically bonded into the inorganic coating material (i.e., the inorganic coating layer). When using the aforementioned high-temperature resistant antibacterial agents to prepare iridescent antibacterial ceramic tiles, under high-temperature calcination conditions, the inorganic coating layer is prone to cracking due to factors such as the limited high-temperature resistance of the inorganic coating layer, the erosion effect of the glaze on the inorganic coating layer, and the mismatch between the thermal expansion coefficients of the inorganic coating layer and the glaze, thus exposing the internal silver oxide. In addition, the glass phase formed in the existing glaze is usually a silicate glass phase. Although the exposed silver ions in the silver oxide can break the Si-O-Si bonds in the silicon-oxygen tetrahedra in the silicate glass phase to form covalent bonds —Si-O-Ag. + However, the rigid silicon-oxygen tetrahedral network structure of silicate glass only allows Ag... + The formation of 4 coordination positions results in relatively weak bonding, and it can only bond to a portion of the exposed Ag in silver oxide. +This means that most of the exposed silver oxide is still easily decomposed into elemental silver and oxygen at high temperatures, resulting in a significant reduction or even complete loss of the antibacterial activity of silver oxide, making it difficult to achieve the ideal antibacterial effect. (2) It is difficult to obtain both antibacterial and iridescent effects at the same time, which is not conducive to meeting the actual application needs. It should be noted that although the elemental silver obtained by calcining and decomposing silver oxide will be re-oxidized, the thermodynamically stable state formed at high temperatures (i.e., elemental Ag) cannot be reconstituted into an effective antibacterial form (i.e., Ag) in the application environment. + This means that silver mainly exists in its elemental form, which has virtually no antibacterial activity.

[0005] In summary, existing high-temperature resistant antibacterial agents generally suffer from the drawback of easily losing their antibacterial activity at high temperatures (i.e., poor high-temperature antibacterial performance) and failing to achieve the desired iridescent effect. This results in tiles made using these agents exhibiting both poor antibacterial properties and the inability to achieve the desired iridescent effect. Furthermore, due to differences in the selection of raw materials in the glaze and the manufacturing process, existing tiles have limited wear resistance and transparency, making it difficult to meet practical usage requirements. Summary of the Invention

[0006] The primary objective of this invention is to propose a color-changing antibacterial ceramic tile and its preparation method, ensuring that the obtained color-changing antibacterial ceramic tile has both antibacterial and color-changing effects, as well as high wear resistance and transparency, to meet practical application needs.

[0007] To achieve this objective, the present invention adopts the following technical solution:

[0008] A method for preparing iridescent antibacterial ceramic tiles includes the following steps:

[0009] A. Prepare ceramic blanks, press the ceramic blanks, and dry them to obtain the blank layer;

[0010] B. Apply iridescent antibacterial glaze to the surface of the body layer to obtain iridescent antibacterial glaze layer;

[0011] According to the mass percentage, the iridescent antibacterial glaze comprises the following raw materials: 5-10 parts iridescent antibacterial frit, 0.5-1.5 parts zircon sand, 5-10 parts kaolin, 15-20 parts quartz, 30-40 parts potassium feldspar, 10-12 parts corundum powder, 3-6 parts calcite, 3-9 parts calcined talc, and 5-10 parts barium carbonate;

[0012] According to the mass fraction, the iridescent antibacterial frit comprises the following raw materials: zirconium silicate, silver-based antibacterial agent, wollastonite, calcium phosphate, perlite, cerium oxide, vanadium dioxide, tungsten trioxide, albite, and boric acid;

[0013] C. After drying, the ceramic tile is fired in a kiln and then polished to obtain iridescent antibacterial ceramic tile.

[0014] Furthermore, in step B, the silver-based antibacterial agent includes any one of silver nitrite, silver nitrate, and silver oxide.

[0015] Furthermore, the cerium oxide has a particle size of 200–800 nm; the perlite has a particle size of 100–500 nm; and the vanadium dioxide has a particle size of 10–40 μm.

[0016] Further, in step B, the iridescent antibacterial frit comprises the following raw materials according to mass parts: 5-10 parts zirconium silicate, 4-8 parts silver-based antibacterial agent, 5-15 parts wollastonite, 5-12 parts calcium phosphate, 15-25 parts perlite, 3-8 parts cerium oxide, 0.2-2 parts vanadium dioxide, 0.01-0.2 parts tungsten trioxide, 25-35 parts albite, and 1-5 parts boric acid.

[0017] Furthermore, in step B, the particle size of the iridescent antibacterial frit is 150–850 μm.

[0018] Furthermore, in step B, the calcination temperature curve of the iridescent antibacterial frit is as follows:

[0019] It takes 0.3 to 0.5 hours to heat the temperature from room temperature to 250°C.

[0020] The temperature rises from 250℃ to 800℃ in 0.5 to 1 hour.

[0021] The temperature rises from 800℃ to 1480℃, taking 2-3 hours.

[0022] 1480℃, keep warm for 0.3 to 0.5 hours.

[0023] Furthermore, in step B, the zircon sand has a particle size of 30–45 μm.

[0024] Furthermore, in step B, the iridescent antibacterial glaze has a residue of 0.3-0.5 wt% on a 325-mesh sieve, a specific gravity of 1.35-1.55, and a flow rate of 30-50 s.

[0025] Furthermore, in step C, the calcination temperature of the iridescent antibacterial ceramic tile is 1150–1250℃, and the calcination time is 45–60 min.

[0026] A type of iridescent antibacterial ceramic tile is prepared using the aforementioned method for preparing iridescent antibacterial ceramic tiles.

[0027] The technical solution provided by this invention may include the following beneficial effects:

[0028] 1. Cerium oxide, vanadium dioxide, tungsten trioxide, and zirconium silicate can form a Ce-WV-Zr solid solution at high temperatures. The Ce-WV-Zr solid solution (refractive index 2.40–3.50) consists of needle-like crystals with a high refractive index. The glassy components in the iridescent antibacterial frit, after calcination, form a glassy phase with a refractive index of 1.54, creating a refractive index difference between the needle-like crystals and the glassy phase. When incident light shines on the glaze of the iridescent antibacterial ceramic tile, the glaze simultaneously exhibits refraction, reflection, and interference. Furthermore, due to the very small thickness of the precipitated needle-like crystals, strong light scattering occurs, resulting in a striking iridescent effect on the glaze of the iridescent antibacterial ceramic tile.

[0029] 2. This technical solution reduces or even prevents the redox decomposition of silver-based antibacterial agents in the early stage of calcination, and combines this with the use of zirconium pyrophosphate crystals and silicate-borate-phosphate mixed glass in the later stage of calcination to counteract Ag. + Stabilize Ag + It forms a stable antibacterial phase, overcoming the tendency of silver-based antibacterial agents to undergo redox decomposition at high temperatures, leading to Ag... + The defect of being reduced to Ag at high temperatures and losing its antibacterial activity can be addressed by using Ag... + High-temperature stabilization endows the iridescent antibacterial frit with high-temperature antibacterial properties.

[0030] 3. During the high-temperature firing process, kaolin decomposes to produce aluminum oxide and silicon dioxide, quartz provides additional silicon dioxide, calcite decomposes to produce calcium oxide, and calcium oxide reacts with aluminum oxide and silicon dioxide to form anorthite crystals (CaAl2Si2O8). Furthermore, aluminum oxide and silicon dioxide can react to form mullite (3Al2O3·2SiO2). Calcined talc decomposes to produce magnesium oxide, which reacts with aluminum oxide and silicon dioxide in the system to form cordierite crystals (Mg2Al2Si2O8). 18 In addition, the incompletely molten zircon sand (mainly composed of ZrSiO4) and the zircon dioxide produced by the decomposition of molten zircon sand are uniformly dispersed as hard phases in the iridescent antibacterial glaze layer, resisting scratches on the glaze surface and further enhancing wear resistance in synergy with the aforementioned crystals. Detailed Implementation

[0031] This technical solution provides a method for preparing iridescent antibacterial ceramic tiles, including the following steps:

[0032] A. Prepare ceramic blanks, press the ceramic blanks, and dry them to obtain the blank layer;

[0033] B. Apply iridescent antibacterial glaze to the surface of the body layer to obtain iridescent antibacterial glaze layer;

[0034] According to the mass percentage, the iridescent antibacterial glaze comprises the following raw materials: 5-10 parts iridescent antibacterial frit, 0.5-1.5 parts zircon sand, 5-10 parts kaolin, 15-20 parts quartz, 30-40 parts potassium feldspar, 10-12 parts corundum powder, 3-6 parts calcite, 3-9 parts calcined talc, and 5-10 parts barium carbonate;

[0035] According to the mass fraction, the iridescent antibacterial frit comprises the following raw materials: zirconium silicate, silver-based antibacterial agent, wollastonite, calcium phosphate, perlite, cerium oxide, vanadium dioxide, tungsten trioxide, albite, and boric acid;

[0036] C. After drying, the ceramic tile is fired in a kiln and then polished to obtain iridescent antibacterial ceramic tile.

[0037] To address the technical issues of poor high-temperature antibacterial properties and the inability to achieve a iridescent effect in existing high-temperature antibacterial agents, this technical solution proposes iridescent antibacterial ceramic tiles, comprising three steps: A (preparing the body layer), B (applying the iridescent antibacterial glaze), and C (firing and polishing). By optimizing the iridescent antibacterial glaze formula, it is beneficial to improve wear resistance and transparency while ensuring both the antibacterial properties and the iridescent effect of the tiles. It should be noted that the body layer in this solution is made from conventional ceramic blanks that have been pressed and dried; further description of the ceramic blanks is omitted here. Additionally, the polishing process is also a commonly used polishing process in the field and will not be described further here.

[0038] Specifically, the raw materials for the iridescent antibacterial frit include cerium oxide, vanadium dioxide, tungsten trioxide, and zirconium silicate. Cerium oxide, vanadium dioxide, tungsten trioxide, and zirconium silicate can form a Ce-WV-Zr solid solution at high temperatures. The Ce-WV-Zr solid solution (refractive index 2.40–3.50) consists of needle-like crystals with a high refractive index. The glassy component in the iridescent antibacterial frit, after calcination, forms a glassy phase with a refractive index of 1.54, creating a refractive index difference between the needle-like crystals and the glassy phase. When incident light shines on the glaze of the iridescent antibacterial ceramic tile, the glaze simultaneously exhibits refraction, reflection, and interference. Furthermore, due to the very small thickness of the precipitated needle-like crystals, strong light scattering occurs, resulting in a striking iridescent effect on the glaze of the iridescent antibacterial ceramic tile.

[0039] Furthermore, vanadium dioxide (VO2) is a semiconductor at low temperatures and a metallic state at high temperatures. That is, vanadium dioxide can undergo a metal-semiconductor phase transition, and during this transition, its crystal structure changes from a monoclinic phase (M, semiconductor state) to a tetragonal phase (R, metallic state). This abrupt change in electronic structure can induce the cerium ion in cerium oxide to change from Ce to... 3+ (Reduced state) and Ce 4+ The change in valence state between these states causes a change in the color of the glaze. Specifically:

[0040] Under low temperature and light conditions, VO2 exists in a semiconductor state, exhibiting a monoclinic structure (M phase), and its band gap (approximately 0.7 eV) allows electrons to transfer to neighboring CeO2 via photoexcitation. The CeO2... 4+ (Pale yellow / colorless) The captured electrons are reduced to Ce. 3+ (Yellow / Red), Ce 3+ The yellow-orange color, combined with the light background of VO2, gives the glaze a soft iridescent sheen.

[0041] Under high temperature and light conditions, VO2 abruptly changes from a semiconductor state to a metallic state (R phase). The free electrons of VO2 act as a mediator, promoting the redistribution of electrons within CeO2, resulting in the oxidation state of CeO2. 4+ The proportion increased, while Ce 4+ The light color of the glaze, combined with the high infrared reflectivity of the R-phase VO2, causes the glaze to turn blue-purple.

[0042] Meanwhile, the raw materials for the iridescent antibacterial frit also include tungsten trioxide (WO3). First, doping or intercalation of WO3 introduces structural distortion and electron cloud rearrangement into the VO2 lattice, lowering the energy barrier (ΔG) between the semiconductor and metallic states of VO2. This allows the energy required for the phase transition to match the room-temperature thermal perturbation (~26 meV), thereby promoting the room-temperature phase transition. Second, the defect pinning effect or stress coupling at the WO3-VO2 interface stabilizes the high-symmetry metallic state (tetragonal phase) of VO2, suppressing its relaxation back to the low-symmetry semiconductor state, thus maintaining a metastable state of VO2 at room temperature. The synergistic effect of lattice manipulation and electronic state modulation allows the phase transition temperature of VO2 to be reduced from 68°C to near room temperature (approximately 32°C).

[0043] Furthermore, the raw materials for the iridescent antibacterial frit also include perlite. Perlite can release bound water at high temperatures, thereby generating water vapor. This water vapor creates numerous bubbles and pores within the glaze layer. The unique microstructure formed by these bubbles and pores is the basis for complex optical phenomena such as light scattering, interference, and refraction, thus contributing to the ever-changing iridescent effect of the iridescent antibacterial ceramic tile glaze.

[0044] Secondly, the raw materials for the iridescent antibacterial frit also include zirconium silicate, silver-based antibacterial agents, wollastonite, calcium phosphate, and boric acid. Calcium phosphate [Ca3(PO4)2] decomposes at high temperatures to produce phosphorus pentoxide (P2O5), which reacts with zirconium silicate (ZrSiO4) to form zirconium pyrophosphate (Zr2P2O7) crystals with a stable crystal structure (melting point > 1600℃). Simultaneously, the silver-based antibacterial agent contains silver ions (Ag) with antibacterial activity. + It can replace Zr in the zirconium pyrophosphate lattice. 4+ Silver-loaded zirconium pyrophosphate (Zr) forms a solid solution structure. 2-x Ag x P2O7). The solid solution structure of silver-supported zirconium pyrophosphate avoids the redox decomposition of silver-based antibacterial agents at high temperatures, preventing Ag from being decomposed. + The drawback of easily being reduced to Ag at high temperatures and losing its antibacterial activity can be overcome by using Ag... + The high-temperature stabilization process endows the iridescent antibacterial frit with high-temperature antibacterial properties, thus giving the iridescent antibacterial glaze with the addition of the iridescent antibacterial frit high-temperature antibacterial properties.

[0045] Among them, zirconium pyrophosphate (Zr2P2O7) crystals are effective against Ag. + The specific mechanism of high-temperature stabilization is as follows: (1) Ag + By ion substitution, it enters the lattice of zirconium pyrophosphate (Zr2P2O7) crystal, forming strong chemical bonds (Zr-O-Ag), with bond energies higher than those of physical coating van der Waals forces; (2) The high melting point of zirconium pyrophosphate gives it high lattice energy, and high lattice energy can effectively suppress Ag under high temperature conditions. + The migration and aggregation of Ag in the crystal lattice + Locked, thus preventing Ag + It was reduced to Ag.

[0046] Simultaneously, during high-temperature calcination, both wollastonite and calcium phosphate decompose to form calcium oxide; boric acid also decomposes to form boron-oxygen tetrahedra; the silicon-oxygen tetrahedra, the silicon dioxide generated from the decomposition of wollastonite, and some of the phosphorus pentoxide generated from the decomposition of calcium phosphate can react with the alkaline oxides in the system (such as calcium oxide introduced by calcium phosphate and sodium oxide introduced by albite) to form borate glass phase, silicate glass phase, and phosphate glass phase respectively, thus forming a silicate-borate-phosphate mixed glass phase after high-temperature calcination. This silicate-borate-phosphate mixed glass phase can react with Ag... + This process stabilizes the silver-based antibacterial agent, thus preventing redox decomposition at high temperatures and the resulting Ag... + The drawback of easily being reduced to Ag at high temperatures and losing its antibacterial activity can be overcome by using Ag... + The high-temperature stabilization process endows the iridescent antibacterial frit with high-temperature antibacterial properties, thus giving the iridescent antibacterial glaze with the addition of the iridescent antibacterial frit high-temperature antibacterial properties.

[0047] Among them, silicate-borate-phosphate mixed glass is relative to Ag + The mechanism for achieving stability is as follows: (1) Ag + It can break the Si-O-Si bonds in the silicon-oxygen tetrahedra and the BOB bonds in the boron-oxygen trihedra in the mixed glass phase, forming a covalent bond structure (—Si-O-Ag). + or—BO-Ag +(2) The [PO4] tetrahedrons in the phosphate glass phase provide an open POP network (bond angle 120-180°), providing a larger interstitial space, enabling Ag+ to form a more stable 6-coordinate [AgO6] structure; (3) P 5+ The high charge density generates stronger electrostatic attraction, through [Ag] + The polarization of ←O=P] further stabilizes Ag. + (4) The chain / ring structure of the phosphate glass phase provides more Ag. + The embedding site, and its distortion energy can be dissipated through PO bond vibration, avoiding local stress leading to Ag. + Release; (5) The calcium phosphate, sodium feldspar and boric acid in the iridescent antibacterial frit lower the melting point of the system and promote sintering. In particular, the fluxing effect of boric acid can not only enable the glass phase to begin to form in the formulation system at a lower temperature to resist Ag + Stabilization can also give the formed mixed glass phase melt high-temperature fluidity, and the high-temperature fluidity of the melt promotes Ag + Rapid diffusion and uniform distribution of Ag throughout the glass phase prevents excessively high local concentrations from causing Ag to diffuse and distribute evenly. + They are aggregated and easily reduced.

[0048] Furthermore, silver-based antibacterial agents (decomposition temperature approximately 440℃) have a relatively low decomposition temperature, while zirconium pyrophosphate crystals begin to form at approximately 900℃, and the silicate-borate-phosphate mixed glass phase begins to form at approximately 600℃. Therefore, during the early calcination stage (i.e., room temperature to 600℃) of the iridescent antibacterial frit, silver-based antibacterial agents are highly susceptible to decomposition (essentially a redox reaction), leading to the degradation of Ag... + It is reduced to Ag (i.e., elemental Ag). However, the calcium phosphate and boric acid introduced into the iridescent antibacterial frit of this technical solution delay or even prevent the decomposition of silver-based antibacterial agents, thus ensuring that the silver in the system mainly exists as antibacterial silver ions (Ag). + It exists in the form of ) . The specific principle of delaying the decomposition of silver-based antibacterial agents is as follows: phosphate ions in calcium phosphate can react with Ag + It forms silver phosphate (Ag3PO4), which has high thermal stability. The Ag in this silver phosphate complex... + With PO4 3- The bonding of silver phosphate (primarily electrostatic interactions with secondary ionic interactions, bond energies approximately 200–300 kJ / mol) can enhance the bonding efficiency of Ag. + Its high redox potential makes it difficult to be reduced to elemental silver during the early stage of calcination (room temperature to 600℃). Furthermore, the gaseous products of boric acid decomposition (such as water vapor and boron trioxide vapor) can locally reduce the oxygen partial pressure, creating a dynamic gaseous protective atmosphere, further inhibiting and slowing the reduction kinetics of silver-based antibacterial agents and preventing Ag from being reduced.+ Premature reduction occurs. During the later stages of calcination (600–1480℃), silver phosphate gradually decomposes and releases Ag. + Subsequently Ag + Ag is achieved by ion exchange into the zirconium pyrophosphate lattice (above 900℃) or into the silicate-borate-phosphate glass phase (above 600℃). + Stability.

[0049] In summary, this technical solution reduces or even prevents the redox decomposition of silver-based antibacterial agents in the early stage of calcination, and combines this with the use of zirconium pyrophosphate crystals and silicate-borate-phosphate mixed glass relative to Ag in the later stage of calcination. + Stabilize Ag + It forms a stable antibacterial phase, overcoming the tendency of silver-based antibacterial agents to undergo redox decomposition at high temperatures, leading to Ag... + The defect of being reduced to Ag at high temperatures and losing its antibacterial activity can be addressed by using Ag... + High-temperature stabilization endows the iridescent antibacterial frit with high-temperature antibacterial properties.

[0050] Furthermore, cerium oxide itself is heat-resistant and exhibits antibacterial properties under both light and dark conditions, thus imparting high-temperature antibacterial properties to the iridescent antibacterial frit. The specific antibacterial principle of cerium oxide is as follows: Under conditions of no light, in the acidic environment produced by bacterial metabolism or under the action of reducing substances (such as thiols), Ce... 4+ Can be reduced to Ce 3+ Simultaneously, reactive oxygen species (ROS, such as hydroxyl radicals and superoxide anion radicals) are generated. These ROS can damage bacterial cell membranes, DNA, and proteins, leading to bacterial death. At the same time, cerium oxide nanoparticles can also be adsorbed onto the bacterial surface through electrostatic interactions, disrupting the integrity of the cell membrane, increasing permeability, and causing leakage of cell contents.

[0051] When cerium oxide is irradiated with ultraviolet or visible light, it absorbs photons and generates photogenerated electrons (electrons). - ) and holes (h + Holes possess strong oxidizing properties, directly oxidizing water or hydroxide ions to generate hydroxyl radicals, or oxidizing oxygen to generate superoxide anion radicals; simultaneously, photogenerated electrons reduce oxygen to generate superoxide anion radicals as well. The concentration of these reactive oxygen species is significantly higher than under light-free conditions, thus enhancing the antibacterial effect.

[0052] In summary, this technology achieves Ag through the synergistic effect of various raw materials. +The high-temperature stabilization of cerium oxide, combined with its inherent high-temperature antibacterial properties, endows the iridescent antibacterial frit with high-temperature antibacterial properties, giving the iridescent antibacterial glaze with the addition of the iridescent antibacterial frit high-temperature antibacterial properties. When the iridescent antibacterial glaze is applied to the surface of the body, it still exhibits excellent antibacterial effects after high-temperature firing.

[0053] It should be noted that CeO2 contains Ce. 4+ The reduction of Ag is mainly driven by the delocalized electrons of VO2 (high-temperature metallic R phase), while Ag... + The reduction of CeO2 requires long-range diffusion or local reducing agents. The reduction mechanism of CeO2 is similar to that of Ag. + It is unrelated to the reduction mechanism. Additionally, Ce... 4+ As a strong oxidizing agent, it tends to be reduced to Ce in redox reactions. 3+ (As in reactions with vitamin E or phenothiazine drugs), rather than as a reducing agent donating electrons. The metal-semiconductor phase transition of VO2 involves a redistribution of electronic structure, but its free electrons are not energetic enough to convert Ag. + The reduction is achieved by decreasing Ag in the early stage of calcination and then reducing Ag in the later stage of calcination. + The stabilizing effect of Ag ensures + The stable existence without disturbing Ce 4+ / Ce 3+ Its redox color-changing function.

[0054] Furthermore, when polishing using existing modules, the grinding block easily opens the pores sealed in the iridescent antibacterial glaze, resulting in a micro-nano porous structure on the glaze surface. This micro-nano porous structure is beneficial for improving antibacterial properties. The specific principle is as follows: (1) The micro-nano porous structure of the glaze surface significantly increases its specific surface area, allowing the antibacterial components to be more fully exposed on the glaze surface, thereby providing more abundant reactive sites. The increase in these reactive sites allows the antibacterial components to come into contact with bacteria more efficiently and trigger a reaction, thereby accelerating the killing or growth inhibition process of bacteria. (2) The sharp edges of the micro-nano porous structure can directly pierce the cell wall or biofilm of bacteria when in contact with them, causing physical damage to the bacteria, thus providing additional protection for the antibacterial properties of the glaze surface.

[0055] Finally, in the preparation process of iridescent antibacterial ceramic tiles, the iridescent antibacterial glaze layer formed after high-temperature calcination of the iridescent antibacterial glaze needs to be polished. However, if the wear resistance of the iridescent antibacterial glaze layer formed after calcination is poor, the mechanical grinding action in the subsequent polishing process can easily lead to excessive wear of the iridescent antibacterial glaze layer, resulting in local or even complete removal, which severely damages the integrity and uniformity of the iridescent antibacterial glaze layer, ultimately causing a significant decrease or even complete loss of antibacterial and iridescent properties. Therefore, to solve the above defects, this technical solution adds kaolin, zircon sand, quartz, calcite, and calcined talc to the iridescent antibacterial glaze formula. These raw materials can give the iridescent antibacterial glaze layer obtained after calcination excellent wear resistance, thereby effectively resisting mechanical wear during the polishing process and ensuring the performance of the iridescent antibacterial glaze layer.

[0056] The mechanism for enhancing wear resistance is as follows: During the high-temperature firing process, kaolin decomposes to generate aluminum oxide and silicon dioxide, quartz provides additional silicon dioxide, calcite decomposes to produce calcium oxide, and calcium oxide reacts with aluminum oxide and silicon dioxide to form anorthite crystals (CaAl2Si2O8). Furthermore, aluminum oxide and silicon dioxide can react to form mullite (3Al2O3·2SiO2); calcined talc decomposes to generate magnesium oxide, and magnesium oxide reacts with aluminum oxide and silicon dioxide in the system to form cordierite crystals (Mg2Al2Si2O8). 18 In addition, the incompletely molten zircon sand (mainly composed of ZrSiO4) and the zircon dioxide produced by the decomposition of molten zircon sand are uniformly dispersed as hard phases in the iridescent antibacterial glaze layer, resisting scratches on the glaze surface and further enhancing wear resistance in synergy with the aforementioned crystals.

[0057] Furthermore, this technical solution limits the proportion of raw materials in the iridescent antibacterial glaze, so that the crystals generated in the iridescent antibacterial glaze are mainly composed of anorthite crystals. Anorthite crystals belong to the triclinic crystal system, have a dense crystal structure, and their refractive index is similar to that of the glass phase of the glaze. There are no significant light scattering centers, so anorthite crystals have extremely high transparency, thereby giving the iridescent antibacterial glaze layer high transparency.

[0058] Preferably, in step B, the thickness of the iridescent antibacterial glaze layer is 0.3–0.7 mm.

[0059] This technical solution limits the thickness of the iridescent antibacterial glaze layer, which helps to ensure that the iridescent antibacterial glaze layer still has a certain thickness after polishing while saving costs, thereby ensuring its antibacterial and iridescent properties.

[0060] To further clarify, in step B, the silver-based antibacterial agent includes any one of silver nitrite, silver nitrate, and silver oxide.

[0061] Both silver nitrite and silver nitrate can introduce silver ions into the system at high temperatures, and silver nitrite, silver nitrate, and silver oxide are all readily available and inexpensive. Therefore, this technical solution preferably uses any one of silver-based antibacterial agents, including silver nitrite, silver nitrate, and silver oxide, to ensure product performance.

[0062] To further explain, the cerium oxide has a particle size of 200–800 nm; the perlite has a particle size of 100–500 nm; and the vanadium dioxide has a particle size of 10–40 μm.

[0063] When the particle size of cerium oxide and vanadium dioxide is too large, it easily increases the roughness of the Ce-WV-Zr solid solution, thus affecting the uniformity of the iridescent effect. When the particle size of cerium oxide and vanadium dioxide is too small, it easily increases the difficulty of grinding, reduces production efficiency, and increases production costs. Therefore, this technical solution limits the particle size of cerium oxide and vanadium dioxide to ensure the uniformity of the iridescent effect at a lower cost.

[0064] Furthermore, if the perlite particle size is too large, the bound water released by the perlite at high temperatures can easily form isolated large pores, resulting in an excessively long light scattering path, sudden changes in light intensity in local areas, and damage to the uniformity of the iridescent effect. If the perlite particle size is too small, the bound water released by the perlite at high temperatures can easily form dense micropores, resulting in overly uniform light scattering, a bland iridescent effect, and a lack of visual impact.

[0065] To further explain, in step B, the iridescent antibacterial frit, calculated by mass, comprises the following raw materials: 5-10 parts zirconium silicate, 4-8 parts silver-based antibacterial agent, 5-15 parts wollastonite, 5-12 parts calcium phosphate, 15-25 parts perlite, 3-8 parts cerium oxide, 0.2-2 parts vanadium dioxide, 0.01-0.2 parts tungsten trioxide, 25-35 parts sodium feldspar, and 1-5 parts boric acid.

[0066] This technical solution optimizes the proportions of each raw material in the high-temperature antibacterial frit formulation, allowing each raw material in the formulation system to fully exert its performance, thereby achieving superior performance of the high-temperature antibacterial frit.

[0067] Preferably, the iridescent antibacterial frit comprises the following raw materials in parts by weight: 8 parts zirconium silicate, 6 parts silver-based antibacterial agent, 10 parts wollastonite, 8 parts calcium phosphate, 20 parts perlite, 5 parts cerium oxide, 0.5 parts vanadium dioxide, 0.02 parts tungsten trioxide, 30 parts albite, and 2 parts boric acid.

[0068] To further explain, in step B, the particle size of the iridescent antibacterial frit is 150–850 μm.

[0069] Because the iridescent antibacterial frit with a particle size of 150–850 μm has a moderate specific surface area, it is beneficial for the slow release of silver ions. Therefore, this technical solution limits the particle size of the iridescent antibacterial frit to 150–850 μm to ensure its performance.

[0070] To further explain, in step B, the calcination temperature curve of the iridescent antibacterial frit is as follows:

[0071] It takes 0.3 to 0.5 hours to heat the temperature from room temperature to 250°C.

[0072] The temperature rises from 250℃ to 800℃ in 0.5 to 1 hour.

[0073] The temperature rises from 800℃ to 1480℃, taking 2-3 hours.

[0074] 1480℃, keep warm for 0.3 to 0.5 hours.

[0075] This technical solution employs a rapid heating approach to the calcination temperature curve of the high-temperature antibacterial frit, thereby reducing the exposure time of silver ions in their unstable high-temperature state. Specifically, the decomposition temperature of silver-based antibacterial agents is typically below 500℃, while this technical solution utilizes a rapid heating strategy from room temperature to 250℃ and from 250℃ to 800℃, significantly reducing the decomposition of silver-based antibacterial agents. Simultaneously, this technical solution shortens the holding time at 1480℃ to 0.3–0.5 hours, ensuring sufficient calcination and maturation of the high-temperature antibacterial frit while minimizing the high-temperature holding time. This allows for the thorough stabilization of silver ions in the silver-based antibacterial agent, thereby enhancing its high-temperature antibacterial performance.

[0076] To further clarify, in step B, the zircon sand has a particle size of 30–45 μm.

[0077] The opacifying effect of zircon sand (whose main chemical composition is ZrSiO4) depends on the ZrO2 nanoparticles (which have a high refractive index and scatter visible light) generated by its high-temperature decomposition. However, when the particle size of zircon sand is limited to 30–45 μm, it is not easy for zircon sand to completely decompose into ZrO2 nanoparticles at high temperatures, which significantly reduces its opacifying effect and helps to ensure the transparency of the iridescent antibacterial glaze layer.

[0078] To further explain, in step B, the iridescent antibacterial glaze has a residue of 0.3-0.5 wt% on a 325-mesh sieve, a specific gravity of 1.35-1.55, and a flow rate of 30-50 s.

[0079] To achieve better antibacterial effects, this technical solution adjusts the fineness, specific gravity, and flow rate of the iridescent antibacterial glaze, ensuring that the tiles have better antibacterial and iridescent effects while improving the quality and stability of the tiles.

[0080] To further explain, in step C, the calcination temperature of the iridescent antibacterial ceramic tile is 1150–1250℃, and the calcination time is 45–60 min.

[0081] This technical solution, by limiting the calcination temperature and time of the iridescent antibacterial ceramic tile, facilitates the formation of a sufficient amount of low-viscosity liquid phase to fill the interparticle gaps, promoting sintering densification. This not only ensures the relative stability of the mixed glass phase relative to Ag... + It stabilizes the structure and improves the density and wear resistance of iridescent antibacterial tiles.

[0082] A type of iridescent antibacterial ceramic tile is prepared using the aforementioned method for preparing iridescent antibacterial ceramic tiles.

[0083] An iridescent antibacterial tile prepared by the above-mentioned method for preparing iridescent antibacterial tiles can improve wear resistance and transparency while ensuring the antibacterial properties and iridescent effect of the iridescent antibacterial tiles.

[0084] The technical solution of the present invention will be further illustrated below through specific embodiments.

[0085] Performance testing:

[0086] Antibacterial properties: The antibacterial properties were tested according to the test method of "JC / T 897-2014 Antibacterial Ceramic Products".

[0087] Antibacterial durability test: The antibacterial durability was tested according to the test method of "JC / T 897-2014 Antibacterial Ceramic Products Antibacterial Properties".

[0088] Iridescent effect: The iridescent effect of the antibacterial tiles at 35℃ and 25℃, as observed with the naked eye under ultraviolet light.

[0089] Abrasion resistance: The abrasion resistance was tested using the test method in GB / T3810.7-2016 Test Methods for Ceramic Tiles Part 7: Determination of Abrasion Resistance of Glazed Tiles Surface.

[0090] Transparency: Observe the transparency of the glaze with the naked eye.

[0091] Example 1

[0092] A. Prepare ceramic blanks, press the ceramic blanks, and dry them to obtain the blank layer;

[0093] B. Apply the iridescent antibacterial glaze to the surface of the body layer to obtain an iridescent antibacterial glaze layer with a thickness of 0.5 mm; wherein, the iridescent antibacterial glaze has a sieve residue of 0.3 wt% after passing through a 325-mesh sieve, a specific gravity of 1.45, and a flow rate of 40 s; calculated by mass parts, the iridescent antibacterial glaze includes the following raw materials: 8 parts iridescent antibacterial frit, 1 part zircon sand with a particle size of 40 μm, 8 parts kaolin, 18 parts quartz, 35 parts potassium feldspar, 11 parts corundum powder, 5 parts calcite, 6 parts calcined talc, and 7 parts barium carbonate; calculated by mass parts, the iridescent antibacterial frit includes the following raw materials: silicate The composition includes 8 parts zirconium, 6 parts silver oxide, 10 parts wollastonite, 8 parts calcium phosphate, 20 parts perlite with a particle size of 300 nm, 5 parts cerium oxide with a particle size of 400 nm, 0.5 parts vanadium dioxide with a particle size of 20 μm, 0.02 parts tungsten trioxide, 30 parts albite, and 2 parts boric acid; the particle size of the iridescent antibacterial frit is 400 μm; the calcination temperature curve of the iridescent antibacterial frit is as follows: from room temperature to 250℃, it takes 0.3 h; from 250℃ to 800℃, it takes 0.5 h; from 800℃ to 1480℃, it takes 2 h; and at 1480℃, it is held for 0.3 h.

[0094] C. After drying, the ceramic tile is fired in a kiln and then polished to obtain a colorful antibacterial ceramic tile. The firing temperature of the colorful antibacterial ceramic tile is 1200℃ and the firing time is 45min.

[0095] Example 2

[0096] A. Prepare ceramic blanks, press the ceramic blanks, and dry them to obtain the blank layer;

[0097] B. Apply the iridescent antibacterial glaze to the surface of the body layer to obtain an iridescent antibacterial glaze layer with a thickness of 0.4 mm; wherein, the iridescent antibacterial glaze has a sieve residue of 0.5 wt% after passing through a 325-mesh sieve, a specific gravity of 1.35, and a flow rate of 30 s; calculated by mass parts, the iridescent antibacterial glaze includes the following raw materials: 5 parts iridescent antibacterial frit, 0.5 parts zircon sand with a particle size of 45 μm, 10 parts kaolin, 20 parts quartz, 38 parts potassium feldspar, 12 parts corundum powder, 5 parts calcite, 8 parts calcined talc, and 9 parts barium carbonate; calculated by mass parts, the iridescent antibacterial frit includes the following raw materials: silicate The composition includes 8 parts zirconium, 4 parts silver nitrite, 12 parts wollastonite, 10 parts calcium phosphate, 18 parts perlite with a particle size of 100 nm, 4 parts cerium oxide with a particle size of 300 nm, 0.4 parts vanadium dioxide with a particle size of 15 μm, 0.05 parts tungsten trioxide, 25 parts albite, and 1 part boric acid; the particle size of the iridescent antibacterial frit is 200 μm; the calcination temperature curve of the iridescent antibacterial frit is as follows: from room temperature to 250℃, it takes 0.5 h; from 250℃ to 800℃, it takes 0.8 h; from 800℃ to 1480℃, it takes 2.5 h; and at 1480℃, it is held for 0.4 h.

[0098] C. After drying, the ceramic tile is fired in a kiln and then polished to obtain a colorful antibacterial ceramic tile. The firing temperature of the colorful antibacterial ceramic tile is 1150℃ and the firing time is 50min.

[0099] Example 3

[0100] A. Prepare ceramic blanks, press the ceramic blanks, and dry them to obtain the blank layer;

[0101] B. Apply the iridescent antibacterial glaze to the surface of the body layer to obtain an iridescent antibacterial glaze layer with a thickness of 0.7 mm; wherein, the iridescent antibacterial glaze has a sieve residue of 0.3 wt% after passing through a 325-mesh sieve, a specific gravity of 1.55, and a flow rate of 50 s; calculated by mass parts, the iridescent antibacterial glaze includes the following raw materials: 10 parts iridescent antibacterial frit, 1.5 parts zircon sand with a particle size of 30 μm, 5 parts kaolin, 15 parts quartz, 30 parts potassium feldspar, 10 parts corundum powder, 4 parts calcite, 4 parts calcined talc, and 6 parts barium carbonate; calculated by mass parts, the iridescent antibacterial frit includes the following raw materials. Materials: 10 parts zirconium silicate, 8 parts silver nitrate, 6 parts wollastonite, 12 parts calcium phosphate, 25 parts perlite with a particle size of 500 nm, 8 parts cerium oxide with a particle size of 600 nm, 1 part vanadium dioxide with a particle size of 40 μm, 0.2 parts tungsten trioxide, 35 parts albite, and 5 parts boric acid; the particle size of the iridescent antibacterial frit is 600 μm; the calcination temperature curve of the iridescent antibacterial frit is as follows: from room temperature to 250℃, it takes 0.4 h; from 250℃ to 800℃, it takes 1 h; from 800℃ to 1480℃, it takes 3 h; 1480℃, held for 0.5 h;

[0102] C. After drying, the ceramic tile is fired in a kiln and then polished to obtain a colorful antibacterial ceramic tile. The firing temperature of the colorful antibacterial ceramic tile is 1250℃ and the firing time is 50min.

[0103] Comparative Example 1

[0104] Comparative Example 1 is a high-temperature resistant antibacterial agent obtained by coating silver oxide with silica in the prior art; the specific preparation method of the high-temperature resistant antibacterial agent is as follows:

[0105] A. Disperse 10 parts by weight of silver oxide evenly in 200 parts by weight of dichloromethane, then add 18 parts by weight of tetraethyl orthosilicate, stir and mix for 10 minutes to obtain the oil phase;

[0106] B. Dissolve 0.5 parts by weight of Tween-20 and 1 part by weight of hexadecyltrimethylammonium bromide in 500 parts by weight of water to obtain an aqueous phase;

[0107] C. Add the oil phase dropwise to the aqueous phase, emulsify at 6000 r / min for 15 min, adjust the pH to 9, heat to 40℃ and stir for 5 h, and obtain a high-temperature resistant antibacterial agent after centrifugation, washing and drying.

[0108] Comparative Example 2

[0109] The preparation method and raw materials of Comparative Example 2 are the same as those of Example 1, except that calcium phosphate was not added to the raw materials of the iridescent antibacterial frit of Comparative Example 2.

[0110] Comparative Example 3

[0111] The preparation method and raw materials of Comparative Example 3 are the same as those of Example 1, except that cerium oxide, vanadium dioxide, tungsten trioxide and zirconium silicate were not added to the raw materials of the iridescent antibacterial frit of Comparative Example 3.

[0112] The performance of the iridescent antibacterial ceramic tiles prepared in the examples and comparative examples was tested, and the results are shown in Table 1 below:

[0113] Table 1. Performance test results of iridescent antibacterial ceramic tiles in the examples and comparative examples.

[0114]

[0115] As can be seen from the test data in Table 1, the iridescent antibacterial ceramic tile obtained by this technical solution exhibits a soft iridescent color at 25℃ and a bluish-purple glaze at 35℃. It has a wear resistance rating of ≥4 (2100 revolutions), high transparency, and an antibacterial rate of ≥99.8% against Escherichia coli and ≥99.5% against Staphylococcus aureus. Its antibacterial durability against Escherichia coli is ≥90%, and its antibacterial durability against Staphylococcus aureus is ≥88%. Therefore, the iridescent antibacterial ceramic tile obtained by this technical solution combines antibacterial properties and an iridescent effect with high wear resistance and transparency to meet practical application needs.

[0116] Comparative Example 1 shows that the iridescent antibacterial ceramic tile obtained by using a high-temperature resistant antibacterial agent in the existing technology has poor antibacterial and iridescent properties.

[0117] In Comparative Example 2, the absence of calcium phosphate not only reduced the redox decomposition of silver-based antibacterial agents in the early stages of calcination, but also prevented the formation of zirconium pyrophosphate and phosphate glass phases using calcium phosphate, thus affecting the activity against Ag. + The fixing effect is not conducive to achieving Ag + High-temperature stabilization affects the antibacterial properties of ceramic tiles.

[0118] In Comparative Example 3, the absence of cerium oxide, vanadium dioxide, tungsten trioxide, and zirconium silicate prevented the formation of a high-refractive-index Ce-WV-Zr solid solution, thus hindering the formation of the iridescent effect. Furthermore, the lack of zirconium silicate also prevented the formation of zirconium pyrophosphate, affecting the reaction with Ag. + The stabilizing effect of Ag is not conducive to achieving Ag +The high-temperature stabilization process affects the antibacterial properties of the tiles. Furthermore, the absence of cerium oxide in the system prevents the utilization of its antibacterial properties in the formulation, further contributing to a decline in antibacterial performance.

[0119] It should be noted that the antibacterial effect of the iridescent antibacterial tiles obtained under no-light conditions was measured in this technical solution. However, given that cerium oxide has a better antibacterial effect under light, it can be predicted that the antibacterial effect of the iridescent antibacterial tiles obtained by this technical solution can at least reach the antibacterial effect tested in this technical solution.

Claims

1. A method for preparing iridescent antibacterial ceramic tiles, characterized in that, Includes the following steps: A. Prepare ceramic blanks, press the ceramic blanks, and dry them to obtain the blank layer; B. Apply iridescent antibacterial glaze to the surface of the body layer to obtain iridescent antibacterial glaze layer; According to the mass percentage, the iridescent antibacterial glaze comprises the following raw materials: 5-10 parts iridescent antibacterial frit, 0.5-1.5 parts zircon sand, 5-10 parts kaolin, 15-20 parts quartz, 30-40 parts potassium feldspar, 10-12 parts corundum powder, 3-6 parts calcite, 3-9 parts calcined talc, and 5-10 parts barium carbonate; According to the mass percentage, the iridescent antibacterial frit comprises the following raw materials: 5-10 parts zirconium silicate, 4-8 parts silver-based antibacterial agent, 5-15 parts wollastonite, 5-12 parts calcium phosphate, 15-25 parts perlite, 3-8 parts cerium oxide, 0.2-2 parts vanadium dioxide, 0.01-0.2 parts tungsten trioxide, 25-35 parts albite, and 1-5 parts boric acid; The calcination temperature curve of the iridescent antibacterial frit is as follows: It takes 0.3 to 0.5 hours to heat the temperature from room temperature to 250°C. The temperature rises from 250℃ to 800℃ in 0.5 to 1 hour. The temperature rises from 800℃ to 1480℃, taking 2-3 hours. 1480℃, heat preservation for 0.3–0.5 hours; C. After drying, the ceramic tile is fired in a kiln and then polished to obtain iridescent antibacterial ceramic tile.

2. The method for preparing a multicolored antibacterial ceramic tile according to claim 1, characterized in that, In step B, the silver-based antibacterial agent includes any one of silver nitrite, silver nitrate, and silver oxide.

3. The method for preparing a multicolored antibacterial ceramic tile according to claim 1, characterized in that, The cerium oxide has a particle size of 200–800 nm; the perlite has a particle size of 100–500 nm; and the vanadium dioxide has a particle size of 10–40 μm.

4. The method for preparing a multicolored antibacterial ceramic tile according to claim 1, characterized in that, In step B, the particle size of the iridescent antibacterial frit is 150–850 μm.

5. The method for preparing a multicolored antibacterial ceramic tile according to claim 1, characterized in that, In step B, the zircon sand has a particle size of 30–45 μm.

6. The method for preparing a multicolored antibacterial ceramic tile according to claim 1, characterized in that, In step B, the iridescent antibacterial glaze has a residue of 0.3-0.5 wt% on a 325-mesh sieve, a specific gravity of 1.35-1.55, and a flow rate of 30-50 s.

7. The method for preparing a multicolored antibacterial ceramic tile according to claim 1, characterized in that, In step C, the calcination temperature of the iridescent antibacterial ceramic tile is 1150–1250℃, and the calcination time is 45–60 min.

8. A multicolored antibacterial ceramic tile, characterized in that, It is prepared using the method for preparing iridescent antibacterial ceramic tiles according to any one of claims 1 to 7.

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