Ceramic rock plate with recessive light-variable decorative effect and preparation method of ceramic rock plate

Abstract

The invention relates to a ceramic rock plate with a hidden light-variable decorative effect and a preparation method of the ceramic rock plate, and belongs to the technical field of ceramic tile production and manufacturing. The water-based recessive optically variable glaze is prepared from the following raw materials in percentage by mass: 30 to 40 percent of high-refractive-index composite component, 1 to 3 percent of diisooctyl sodium sulfosuccinate, 5 to 10 percent of propylene glycol, 10 to 15 percent of acrylic emulsion, 1 to 2 percent of defoaming agent and 35 to 45 percent of water, wherein the high-refractive-index composite component is a silane coupling agent modified lead frit bead dry particle with the surface coated with a titanium dioxide film. By using the water-based recessive optically variable glaze, the recessive effect of optically variable line textures and accurate positioning of imitation stone patterns are realized.

Description

Technical Field

[0001] This invention relates to a ceramic slab with a hidden light-changing decorative effect and its preparation method, belonging to the field of ceramic tile production and manufacturing technology. Background Technology

[0002] The density of existing building ceramic tiles is approximately 2.3–2.4 g / cm³. 3 Due to their large weight per unit area, applying existing building ceramic tiles to exterior wall decoration not only places a significant burden on the building's exterior walls but also makes them prone to detachment, causing safety accidents. Meanwhile, with the increasing demands for energy conservation and emission reduction in buildings, the construction of low-carbon cities, and the development of low-carbon buildings, high-tech energy conservation, low consumption, and environmental protection have become the development themes of the construction industry.

[0003] Traditional methods primarily employ screen printing to achieve precise alignment of glaze and pattern textures. However, screen printing is only suitable for small-sized ceramic tiles and cannot achieve texture positioning for large-sized ceramic slabs. Furthermore, the screen printing stencil can only create patterns printed on it, which greatly limits the decorative effect. Summary of the Invention

[0004] To address the aforementioned problems, this invention provides a ceramic slab with a subtle optically variable decorative effect and its preparation method. By using a water-based subtle optically variable glaze, the subtle effect of the optically variable lines and textures and the precise positioning of the stone-like pattern are achieved.

[0005] In a first aspect, the present invention provides a water-based invisible photochromic glaze. The raw material composition of the water-based invisible photochromic glaze, by mass percentage, includes: 30-40% high refractive index composite component, 1-3% sodium diisooctyl succinate sulfonate, 5-10% propylene glycol, 10-15% acrylic emulsion, 1-2% defoamer, and 35-45% water; wherein the high refractive index composite component is a silane coupling agent-modified lead frit spherical dry granules coated with a titanium dioxide film.

[0006] Preferably, lead frit is prepared into dry lead frit beads using a melt method; a titanium dioxide film is coated on the surface of the dry lead frit beads; and the surface of the dry lead frit beads coated with titanium dioxide film is modified using a silane coupling agent to obtain a high refractive index composite component.

[0007] Preferably, the chemical composition of the lead ingot, by mass percentage, includes: SiO2: 25-30%, Al2O3: 5-10%, Fe2O3: 0.2-0.6%, PbO: 60-70%, CaO: 0.1-0.5%, MgO: 0.1-0.5%, K2O: 0.2-0.6%, and Na2O: 0.2-0.7%.

[0008] Preferably, the particle size distribution of the dry lead frit beads, by mass percentage, includes: 5-10% for 30-60 mesh, 85-90% for 60-80 mesh, and ≤5% for less than 80 mesh.

[0009] Secondly, the present invention provides a method for preparing a ceramic slab with a subtle optically variable decorative effect. The preparation method includes: Apply a surface glaze to the body; Inkjet printing of patterns on the surface of the blank after glazing; Apply a protective glaze to the surface of the blank after inkjet printing the pattern; Apply any of the above-mentioned water-based invisible optical variable glazes to the surface of the body after applying the protective glaze; The ceramic slab with a hidden light-changing glaze is fired and polished after being coated with water-based invisible light-changing glaze.

[0010] Preferably, the chemical composition of the glaze, by mass percentage, includes: SiO2: 61-65%, Al2O3: 19-23%, K2O: 3-4%, Na2O: 3.1-3.8%, CaO: 0.5-1.0%, MgO: 0.5-1.0%, ZrO2: 3.2-9.6%, and loss on ignition: 1.5-2%.

[0011] Preferably, the glaze is applied by spraying; the specific gravity of the glaze is 1.3–1.5 g / cm³. 3 The glaze application rate is 500-600 g / m². 2 .

[0012] Preferably, the chemical composition of the protective glaze, by mass percentage, includes: SiO2: 45-50%, Al2O3: 18-22%, CaO: 0.1-1.0%, MgO: 4-6%, BaO: 10-13%, ZnO: 2-4%, K2O: 3-5%, Na2O: 1-2%, and loss on ignition: 3-6%.

[0013] Preferably, the protective glaze is applied by spraying; the specific gravity of the protective glaze is 1.3–1.6 g / cm³. 3 The glaze application rate is 400-500 g / m². 2 .

[0014] Preferably, the billet is a lightweight billet; the raw material composition of the lightweight billet includes basic minerals and added silicon carbide, wherein the basic minerals include, by mass percentage: 35-60% clay, 10-30% high-potassium sand, and 20-40% potassium feldspar; and silicon carbide accounts for 0.3-0.6 wt% of the basic minerals.

[0015] Preferably, the chemical composition of the lightweight blank, by mass percentage, includes: loss on ignition: 4-6%, SiO2: 65-70%, Al2O3: 18-22%, Fe2O3: 0.2-0.6%, TiO2: 0.01-0.05%, CaO: 0.2-0.6%, MgO: 0.1-0.5%, K2O: 4-7%, and Na2O: 1-2%.

[0016] Preferably, the firing temperature is 1135–1160℃ and the firing time is 60–80 min.

[0017] Thirdly, the present invention also provides a ceramic slab with a hidden light-changing decorative effect, which is obtained by any of the preparation methods described above. Attached Figure Description

[0018] Figure 1 This is a diagram showing the light-changing effect of the ceramic rock slab with hidden light-changing decorative effect in Example 1 under light. Figure 2 The left image is the design layout file, and the right image is a line drawing obtained by extracting lines from the left image; Figure 3 This is a rendering of the ceramic slab surface effect in Comparative Example 2. Detailed Implementation

[0019] The present invention is further illustrated by the following embodiments. It should be understood that the following embodiments are for illustrative purposes only and are not intended to limit the present invention. Unless otherwise specified, all percentages refer to mass percentages. The following exemplifies the method for preparing the ceramic slab with a subtle optically variable decorative effect according to the present invention. The subtle effect refers to the fact that the line effect is only visible when the glaze is viewed from a specific angle.

[0020] Preparation of the green body. Commonly used ceramic green bodies in this field can be selected. The chemical composition and raw material composition of the green body are not limited. For example, the chemical composition of the green body, by mass percentage, includes: SiO2: 60–70%, Al2O3: 15–25%, Fe2O3: 0.1–0.8%, TiO2: 0.01–0.1%, CaO: 0.2–0.6%, MgO: 0.2–0.6%, K2O: 2.0–8.0%, Na2O: 1.0–3.5%, and loss on ignition: 3.5–5.5%.

[0021] The green body is preferably a lightweight green body. The raw material composition of the lightweight green body includes base minerals and added silicon carbide. The base minerals of the lightweight green body, by mass percentage, may include: clay 35-60%, high-potassium sand 10-30%, and potassium feldspar 20-40%. Silicon carbide accounts for 0.3-0.6 wt% of the base minerals. The chemical composition of the high-potassium sand, by mass percentage, includes: loss on ignition: 3-5%, SiO2: 65-70%, Al2O3: 17-22%, Fe2O3: 0.5-1%, TiO2: 0.01-0.05%, CaO: 0.01-0.05%, MgO: 0.1-0.5%, K2O: 4-7%, and Na2O: 0.5-1%.

[0022] The chemical composition of the lightweight preform, by mass percentage, may include: loss on ignition: 2-6%, SiO2: 65-70%, Al2O3: 18-22%, Fe2O3: 0.2-0.6%, TiO2: 0.01-0.1%, CaO: 0.2-0.6%, MgO: 0.1-0.5%, K2O: 4-7%, Na2O: 1-2%.

[0023] The lightweight green body achieves lightweighting by introducing a small amount of silicon carbide to induce micro-foaming of the green body and combining it with a high-potassium formula, which can reduce the density of the green body and ensure mechanical strength at the same time.

[0024] The raw materials are batched (weighed) according to their composition. After mixing, water is added, and the mixture is ball-milled, sieved to remove iron, spray-dried, and aged to obtain a green body slurry. The ball mill speed can be adjusted as needed. The ball milling time can be 10–15 hours. The fineness of the green body slurry passing through a 250-mesh sieve can reach 0.3–0.5 wt%. The slurry is then spray-granulated to obtain green body powder.

[0025] The raw material powder is pressed into a blank to obtain a blank. A press can be used for pressing. There are no restrictions on the forming method, including but not limited to dry pressing.

[0026] Dry the billet. The drying temperature can be 150–200℃, and the drying time can be 40–60 min. The moisture content of the dried billet can be 0.2–0.3 wt%.

[0027] The bulk density of the lightweight preform can be 1.5–1.95 g / cm³. 3 With a strength ≥35MPa, it meets the industry standards for ceramic tiles.

[0028] High-sodium billets were also used. The raw material composition of the high-sodium billets included base minerals and added silicon carbide. The base minerals of the high-sodium billets, by mass percentage, included: clay 40%, medium-temperature sand 20%, and albite 40%. Silicon carbide accounted for 0.5 wt% of the base minerals. The chemical composition of the billet, by mass percentage, included: loss on ignition: 4.3%, SiO2: 67.56%, Al2O3: 20.54%, Fe2O3: 0.28%, TiO2: 0.07%, CaO: 0.35%, MgO: 0.28%, K2O: 0.8%, and Na2O: 5%. The bulk density of the high-sodium billet was 1.80 g / cm³. 3 The strength is 29 MPa and the water absorption rate is 0.05 wt%. Due to the low viscosity of the high-sodium green body at high temperatures, a large number of large pores are formed after firing, thus reducing the strength of the green body.

[0029] Apply a top coat of glaze to the dried body. Conventional glazes in this field can be used. The purpose of the glaze is to cover the base color and imperfections of the body and promote the color development of the inkjet pattern.

[0030] The chemical composition of the glaze, by mass percentage, includes: SiO2: 61-65%, Al2O3: 19-23%, K2O: 3-4%, Na2O: 3.1-3.8%, CaO: 0.5-1.0%, MgO: 0.5-1.0%, ZrO2: 3.2-9.6%, and loss on ignition: 1.5-2%.

[0031] The mineral composition of the glaze, by mass percentage, includes: 10-15% kaolin, 30-40% potassium feldspar, 20-30% sodium feldspar, 5-10% zirconium silicate, and 5-35% calcined clay.

[0032] Weigh each raw material according to the mineral composition of the glaze, mix it with sodium tripolyphosphate, sodium carboxymethyl cellulose, and water, ball mill until homogeneous, and sieve to remove iron to obtain the glaze slurry. For example, the glaze slurry comprises, by mass percentage: 50-80% glaze minerals, 0.1-0.5% sodium tripolyphosphate, 0.1-0.5% sodium carboxymethyl cellulose, and 20-40% water. The residue of the glaze slurry passing through a 325-mesh sieve is ≤0.8wt%. Water can be added to the glaze slurry during application to adjust the final desired glaze specific gravity.

[0033] The surface glaze can be applied by spraying. Preferably, the specific gravity of the surface glaze is 1.3–1.5 g / cm³. 3 The glaze application rate is 500-600 g / m². 2 Controlling the specific gravity and amount of glaze within the above range allows the glaze to evenly cover the body, which is beneficial for the color development of inkjet patterns.

[0034] The pattern is printed using inkjet printing on the surface of the glazed body. Digital inkjet printers can be used. Inkjet printing colors include, but are not limited to, blue, reddish-brown, orange, golden yellow, lemon yellow, black, and red. The texture and color effects of the inkjet-printed pattern will vary according to design requirements.

[0035] The blank after inkjet printing is dried. The drying temperature can be 100-150℃.

[0036] A protective glaze is applied to the surface of the ceramic tile after the inkjet-printed pattern has dried. Conventional protective glazes in this field can be used. The purpose of the protective glaze is to improve the surface stain resistance and wear resistance of the ceramic tile.

[0037] The chemical composition of the protective glaze, by mass percentage, includes: SiO2: 45-50%, Al2O3: 18-22%, CaO: 0.1-1.0%, MgO: 4-6%, BaO: 10-13%, ZnO: 2-4%, K2O: 3-5%, Na2O: 1-2%, and loss on ignition: 3-6%.

[0038] The mineral composition of the protective glaze, by mass percentage, includes: 50-60% potassium feldspar, 10-15% kaolin, 10-15% barium carbonate, 6-11% calcined talc, 2-5% zinc oxide, and 10-15% quartz powder.

[0039] Weigh each raw material according to the mineral composition of the protective glaze, mix it with sodium tripolyphosphate, sodium carboxymethyl cellulose, and water, ball mill until homogeneous, and sieve to remove iron to obtain a protective glaze slurry. For example, the protective glaze slurry comprises, by mass percentage: 50-80% protective glaze minerals, 0.1-0.5% sodium tripolyphosphate, 0.1-0.5% sodium carboxymethyl cellulose, and 20-40% water. The residue of the protective glaze slurry passing through a 325-mesh sieve is ≤0.8wt%. When applying the protective glaze, water can be added to the glaze slurry to adjust the final desired specific gravity.

[0040] The protective glaze can be applied by spraying. Preferably, the specific gravity of the protective glaze is 1.3–1.6 g / cm³. 3 The glaze application rate is 400-500 g / m². 2 Controlling the specific gravity and amount of protective glaze within the above range can prevent incomplete polishing after ceramic tile polishing.

[0041] A high-refractive-index composite component was prepared. High-refractive-index lead frit was processed into spherical dry granules using a melt method. A high-refractive-index titanium dioxide film was then coated onto the surface of the granules. Further surface modification of the titanium dioxide film was performed using a silane coupling agent to obtain the high-refractive-index composite component. This high-refractive-index composite component can be used as a reflective enhancement component for glazed mirrors, thereby achieving a subtle optical variable decorative effect.

[0042] A high-refractive-index lead molten ingot is prepared into spherical dry granules using a melt method. The chemical composition of the lead molten ingot, by mass percentage, includes: SiO2: 25-30%, Al2O3: 5-10%, Fe2O3: 0.2-0.6%, PbO: 60-70%, CaO: 0.1-0.5%, MgO: 0.1-0.5%, K2O: 0.2-0.6%, and Na2O: 0.2-0.7%. Lead has a high atomic number, therefore the lead molten ingot can provide a high refractive index (reaching 1.8-2.0). The lead molten ingot is injected with a high-pressure gas stream, forming fibrous strip-shaped particles in a furnace tower. Under the combined action of the high-pressure flame and its own surface tension, the fibrous strip-shaped particles shrink into spherical granules. After cooling, the granules are sieved to remove the fibrous strip-shaped particles, obtaining the lead molten ingot spherical dry granules.

[0043] The particle size distribution of the lead frit granules, by mass percentage, includes: 5-10% for 30-60 mesh, 85-90% for 60-80 mesh, and ≤5% for below 80 mesh. Below 80 mesh refers to the portion that passes through an 80-mesh sieve. If the granules are too fine, the subtle optical variable effect is weakened; if the granules are too coarse, they easily clog the nozzle, leading to sedimentation.

[0044] If lead frit is prepared into non-circular irregular particles, the fluidity of the water-based invisible photochromic glaze will be reduced, and it will also be more prone to clogging the nozzle.

[0045] A high-refractive-index titanium dioxide film is coated onto the surface of lead fused pellets. The titanium dioxide film is deposited on the pellet surface using a pulsed magnetron sputtering titanium target. By adjusting the sample holder's oscillation frequency (e.g., 20–25 times / min) and ultrasonic vibration power (e.g., 10–12 W), each pellet vibrates continuously while rolling, ensuring full surface exposure. The magnetron sputtering process parameters include: working pressure in the vacuum chamber 0.7–1 Pa, pulse power 750–800 W, hydrogen flow rate 10–12 sccm, oxygen flow rate 2–3 sccm, sputtering temperature 250–300 °C, and sputtering time 30–40 min. The thickness of the titanium dioxide film can be 1–3 mm.

[0046] Lead frit has a relatively low refractive index, while titanium dioxide has a relatively high refractive index. By coating the surface of dry lead frit beads with a titanium dioxide film, the refractive index of the composite component can be increased. If only the dry lead frit beads and titanium dioxide particles are physically mixed, the overall refractive index of the resulting composite will be low, and the desired subtle optical variable effect cannot be achieved.

[0047] High-refractive-index composite components were obtained by surface modification of lead fused pellets coated with a titanium dioxide film using a silane coupling agent. The type of silane coupling agent is not limited; commonly used silane coupling agents in the art can be used. The silane coupling agent includes, but is not limited to, at least one of 3-aminopropyltriethoxysilane, γ-(2,3-epoxypropoxy)propyltrimethoxysilane, γ-(methacryloyloxy)propyltrimethoxysilane, γ-methacryloyloxypropyl, and γ-mercaptopropyltrimethoxysilane. For example, 3-aminopropyltriethoxysilane was specifically used in the examples and comparative examples.

[0048] For example, lead fused pellets coated with a titanium dioxide film are immersed in anhydrous ethanol to obtain a dry pellet mixture. The volume ratio of the lead fused pellets coated with titanium dioxide film to anhydrous ethanol is 1:5–10. A silane coupling agent, 3-aminopropyltriethoxysilane, is mixed with water at a volume ratio of 1:1–3 to obtain a silane coupling agent mixture. The silane coupling agent mixture and the dry pellet mixture are further mixed at a mass ratio of 5–8:1, and then heated to 70–90°C with stirring for 3–5 hours. After the reaction is complete, the residual silane coupling agent on the surface of the dry pellets is washed off with water, and the pellets are dried again to obtain a high refractive index composite component.

[0049] A water-based invisible photochromic glaze was prepared. The raw material composition of the water-based invisible photochromic glaze, by mass percentage, includes: 30-40% high refractive index composite component, 1-3% sodium diisooctyl succinate sulfonate, 5-10% propylene glycol, 10-15% acrylic emulsion, 1-2% defoamer, and 35-45% water. The solid content of the acrylic emulsion can be 40-60%, and the solvent is water. For example, in the examples and comparative examples, SHYT-828 acrylic emulsion provided by Polychem Chemicals was specifically used. Commonly used defoamers in the art can be used, including but not limited to alcohol defoamers, fatty acid and fatty acid ester defoamers, amide defoamers, phosphate ester defoamers, silicone defoamers, polyether defoamers, and polyether-modified polysiloxane defoamers. For example, a polyether defoamer was specifically used in the examples and comparative examples.

[0050] In the aforementioned water-based invisible optically variable glaze, sodium diisooctyl succinate sulfonate serves as an aqueous dispersant, and propylene glycol as a moisturizing solvent. Based on the synergistic effect of electrostatic stability and steric hindrance, a water-based invisible optically variable glaze with good suspension properties and stability is obtained. The viscosity of the water-based invisible optically variable glaze is 40–60 mPa·s, and the pH value is 7–8. In some embodiments, the solid content of the water-based invisible optically variable glaze is 45 wt%, and the slurry sedimentation rate after 24 hours is <5%.

[0051] Apply a water-based, invisible, photochromic glaze to the surface of the body after applying a protective glaze. For example, a 2D digital cloth system can be used to apply the water-based, invisible, photochromic glaze to the surface of the body after applying a protective glaze. Figure 3As shown, lines are first extracted from the original layout design to form an effect image, and then the line texture of the invisible photochromic glaze is printed according to the effect image. This allows for precise positioning of the invisible photochromic line texture and the imitation stone pattern. The 2D digital cloth system used in the embodiments and comparative examples is manufactured by Sepfit Technology Co., Ltd. In use, the water-based invisible photochromic glaze is loaded into the 2D digital cloth system and then operated according to the instructions. This invention places the water-based invisible photochromic glaze on top of the protective glaze layer. Because the melting point of lead frit is low, pinholes can be avoided after the water-based invisible photochromic glaze is fired due to the protective glaze covering it.

[0052] The body after applying water-based invisible photochromic glaze is dried. The drying temperature can be 100-120℃, and the drying time can be 10-20 minutes.

[0053] Firing in a kiln. The firing temperature can be 1135–1160℃, and the firing time can be 60–80 minutes.

[0054] Polishing. Waxing. Packaging.

[0055] This invention uses a melt method to prepare high-refractive-index lead frit into spherical dry granules. A high-refractive-index titanium dioxide film is then coated onto the surface of these granules to form a high-reflectivity component. This high-reflectivity component is further modified using a silane coupling agent to form a high-refractive-index composite component. More importantly, this invention utilizes the aforementioned high-refractive-index composite component, combined with composite additives, to develop a water-based, invisible optically variable glaze with excellent stability and a subtle optically variable decorative effect. A 2D digital fabric system is used to imbue it with a specific texture; after firing, the lines and textures exhibit higher brightness under sidelight, creating an invisible optically variable effect.

[0056] The following examples further illustrate the present invention in detail. It should also be understood that the following examples are only for further explanation of the present invention and should not be construed as limiting the scope of protection of the present invention. Any non-essential improvements and adjustments made by those skilled in the art based on the above description of the present invention are within the scope of protection of the present invention. The specific process parameters, etc., in the following examples are merely examples within a suitable range; that is, those skilled in the art can make appropriate selections within the appropriate range based on the description herein, and are not intended to be limited to the specific values ​​in the examples below.

[0057] Example 1

[0058] Methods for preparing ceramic slabs with subtle optically variable decorative effects include:

[0059] Step 1. Prepare a lightweight green body. The raw material composition of the lightweight green body includes base minerals and added silicon carbide, wherein the base minerals, by mass percentage, include: clay 52%, high-potassium sand 10%, and potassium feldspar 38%. Silicon carbide accounts for 0.5 wt% of the base minerals. The chemical composition of the lightweight green body, by mass percentage, includes: loss on ignition: 3.8%, SiO2: 69.2%, Al2O3: 18.8%, Fe2O3: 0.26%, TiO2: 0.06%, CaO: 0.44%, MgO: 0.2%, K2O: 6%, and Na2O: 1.24%.

[0060] Step 2. Apply a surface glaze to the surface of the blank. The chemical composition of the surface glaze, by mass percentage, includes: SiO2: 61.0%, Al2O3: 23%, K2O: 4%, Na2O: 3.5%, CaO: 1.0%, MgO: 0.5%, ZrO2: 5%, and loss on ignition: 2%. The surface glaze is applied by spraying. The specific gravity of the surface glaze is 1.4 g / cm³. 3 Glazing amount is 500g / m 2 .

[0061] Step 3. Print a pattern on the surface of the glazed body using inkjet printing.

[0062] Step 4. Dry the blank after inkjet printing pattern.

[0063] Step 5. Apply a protective glaze to the surface of the inkjet-printed and dried blank. The chemical composition of the protective glaze, by mass percentage, includes: SiO2: 50%, Al2O3: 20%, CaO: 0.1%, MgO: 4%, BaO: 13%, ZnO: 4%, K2O: 3%, Na2O: 2%, and loss on ignition: 3.9%. The protective glaze is applied by spraying. The specific gravity of the protective glaze is 1.5 g / cm³. 3 Glazing amount is 400g / m 2 .

[0064] Step 6. Preparation of high refractive index composite components. High refractive index lead molten metal is prepared into spherical dry granules using a melt method. The chemical composition of the lead molten metal, by mass percentage, includes: SiO2: 25%, Al2O3: 5%, Fe2O3: 0.2%, PbO: 69.2%, CaO: 0.1%, MgO: 0.1%, K2O: 0.2%, Na2O: 0.2%. The particle size distribution of the lead molten metal spherical dry granules, by mass percentage, includes: 30-60 mesh 7%, 60-80 mesh 90%, and below 80 mesh 3%. A titanium dioxide thin film is deposited on the surface of the spherical dry granules using pulsed magnetron sputtering on a titanium target. The magnetron sputtering process parameters include: working pressure in the vacuum chamber 0.7 Pa, pulse power 750 W, hydrogen flow rate 10 sccm, oxygen flow rate 2 sccm, sputtering temperature 250℃, and sputtering time 30 min. The thickness of the titanium dioxide film is 1 mm. Lead fused pellets coated with a titanium dioxide film were immersed in anhydrous ethanol to obtain a dry pellet mixture. The volume ratio of the lead fused pellets coated with titanium dioxide film to anhydrous ethanol was 1:5. A silane coupling agent, 3-aminopropyltriethoxysilane, was mixed with water at a volume ratio of 1:2 to obtain a silane coupling agent mixture. The silane coupling agent mixture and the dry pellet mixture were further mixed at a mass ratio of 5:1, and then heated to 70°C and stirred for 3 hours. After the reaction was completed, the residual silane coupling agent on the surface of the dry pellets was washed off with water, and the pellets were dried again to obtain the high refractive index composite component.

[0065] Step 7. Prepare the water-based invisible photochromic glaze. The raw material composition of the water-based invisible photochromic glaze, by mass percentage, includes: high refractive index composite component: 40%, sodium diisooctyl succinate sulfonate: 3%, propylene glycol: 5%, acrylic emulsion: 10%, defoamer: 2%, and water: 40%.

[0066] Step 8. Apply a water-based invisible optical variable glaze to the surface of the body after the protective glaze has been applied using a 2D digital cloth system.

[0067] Step 9. Dry the body after applying the water-based invisible light-changing glaze.

[0068] Step 10. Firing. The firing temperature is 1140℃, and the firing time is 60 minutes.

[0069] Step 11. Polish, wax, and pack.

[0070] Figure 1 This is an image showing the light-changing effect of the ceramic slab with the subtle light-changing decorative effect in Example 1 under light. It can be seen that the gloss of the lines and textures is higher than that of the surrounding glaze, and the lines appear subtly visible from different angles. That is, the line effect is only visible when observing the glaze from a specific angle.

[0071] Comparative Example 1

[0072] The process is basically the same as in Example 1, except that the particle size distribution of the dry lead frit beads, by mass percentage, includes: 5% for 30-60 mesh, 5% for 60-80 mesh, and 90% for less than 80 mesh.

[0073] Because the dry granules of the round beads are too fine, the latent optical variable effect of Comparative Example 1 is weakened.

[0074] Comparative Example 2

[0075] It is basically the same as Example 1, except that the high refractive index composite component is replaced with zircon sand.

[0076] Figure 3 This is a comparison image of the ceramic slab brick surface effect. It can be seen that numerous pinholes appear on the brick surface after firing. This is because the initial melting temperature of the zircon sand particles is relatively high, increasing the viscosity of the local glaze, making it difficult for gas to escape, causing bubbles to easily form on the glaze surface, resulting in pinholes after polishing.

[0077] Comparative Example 3

[0078] It is basically the same as Example 1, except that the high refractive index composite component is replaced with titanium dioxide.

[0079] The light-changing ability of the corresponding ratio is also weakened. This is because the initial melting temperature of titanium dioxide particles is also relatively high, which increases the viscosity of the local glaze, making it difficult for gas to escape. The glaze is prone to bubbles, and pinholes are likely to appear after polishing.

[0080] Comparative Example 4

[0081] It is basically the same as Example 1, except that the order of applying the protective glaze and the water-based invisible light-changing glaze is changed.

[0082] The light-changing effect is weakened in the comparison ratio because the water-based invisible light-changing glaze has a higher density. When it is covered on the protective glaze, it will sink to a certain depth during the firing process. After polishing, the light-changing lines will be exposed. Therefore, if the protective glaze covers the water-based invisible light-changing glaze, it will affect the reflection of light on the glaze surface and affect the light-changing effect.

Claims

1. A water-based invisible optically variable glaze, characterized in that, The raw material composition of the water-based invisible photochromic glaze, by mass percentage, includes: 30-40% high refractive index composite component, 1-3% sodium diisooctyl succinate sulfonate, 5-10% propylene glycol, 10-15% acrylic emulsion, 1-2% defoamer, and 35-45% water; wherein, the high refractive index composite component is a dry lead frit bead coated with a titanium dioxide film and modified with a silane coupling agent.

2. The water-based invisible optically variable glaze according to claim 1, characterized in that, Lead frit is prepared into dry lead frit beads using a melt method; a titanium dioxide film is coated on the surface of the dry lead frit beads; the surface of the dry lead frit beads coated with titanium dioxide film is modified with a silane coupling agent to obtain a high refractive index composite component.

3. The water-based invisible optically variable glaze according to claim 2, characterized in that, The chemical composition of the lead ingot, by mass percentage, includes: SiO2: 25-30%, Al2O3: 5-10%, Fe2O3: 0.2-0.6%, PbO: 60-70%, CaO: 0.1-0.5%, MgO: 0.1-0.5%, K2O: 0.2-0.6%, and Na2O: 0.2-0.7%.

4. The water-based invisible optically variable glaze according to claim 2 or 3, characterized in that, The particle size distribution of the dry lead frit beads, by mass percentage, includes: 5-10% for 30-60 mesh, 85-90% for 60-80 mesh, and ≤5% for below 80 mesh.

5. A method for preparing a ceramic slab with a subtle optically variable decorative effect, characterized in that, The preparation method includes: applying a surface glaze to the surface of the blank; Inkjet printing of patterns on the surface of the blank after glazing; Apply a protective glaze to the surface of the blank after inkjet printing the pattern; Apply a water-based invisible optical variable glaze according to any one of claims 1 to 4 to the surface of the body after applying a protective glaze; The ceramic slab with a hidden light-changing glaze is fired and polished after being coated with water-based invisible light-changing glaze.

6. The preparation method according to claim 5, characterized in that, The chemical composition of the glaze, by mass percentage, includes: SiO2: 61-65%, Al2O3: 19-23%, K2O: 3-4%, Na2O: 3.1-3.8%, CaO: 0.5-1.0%, MgO: 0.5-1.0%, ZrO2: 3.2-9.6%, and loss on ignition: 1.5-2%.

7. The preparation method according to claim 5 or 6, characterized in that, The glaze is applied by spraying; the specific gravity of the glaze is 1.3–1.5 g / cm³. 3 The glaze application rate is 500-600 g / m². 2 .

8. The preparation method according to any one of claims 5 to 7, characterized in that, The chemical composition of the protective glaze, by mass percentage, includes: SiO2: 45-50%, Al2O3: 18-22%, CaO: 0.1-1.0%, MgO: 4-6%, BaO: 10-13%, ZnO: 2-4%, K2O: 3-5%, Na2O: 1-2%, and loss on ignition: 3-6%.

9. The preparation method according to any one of claims 5 to 8, characterized in that, The protective glaze is applied by spraying; the specific gravity of the protective glaze is 1.3–1.6 g / cm³. 3 The glaze application rate is 400-500 g / m². 2 .

10. The preparation method according to any one of claims 5 to 9, characterized in that, The billet is a lightweight billet; the raw material composition of the lightweight billet includes basic minerals and added silicon carbide, wherein the basic minerals include, by mass percentage: 35-60% clay, 10-30% high-potassium sand, and 20-40% potassium feldspar; and silicon carbide accounts for 0.3-0.6 wt% of the basic minerals.

11. The preparation method according to claim 10, characterized in that, The chemical composition of the lightweight preform, by mass percentage, includes: loss on ignition: 2-6%, SiO2: 65-70%, Al2O3: 18-22%, Fe2O3: 0.2-0.6%, TiO2: 0.01-0.1%, CaO: 0.2-0.6%, MgO: 0.1-0.5%, K2O: 4-7%, and Na2O: 1-2%.

12. The preparation method according to any one of claims 5 to 11, characterized in that, The firing temperature is 1135~1160℃, and the firing time is 60~80min.

13. A ceramic slab with a subtle optically variable decorative effect, characterized in that, The ceramic slab with the hidden light-changing decorative effect is obtained by the preparation method according to any one of claims 5 to 12.

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