Glazing process of pickling-free self-cleaning ceramic tile

Abstract

The invention relates to the technical field of glazing processes, in particular to a glazing process of a pickling-free self-cleaning ceramic tile. The process comprises the following steps: performing low-temperature biscuit firing on a green body, applying basic glaze containing a self-cleaning component, performing triple digital ink jet to construct a stone texture, performing digital glue dry particle molding to form a concave-convex structure, and finally performing stepped heating and high-temperature slow firing without strong acid treatment in the whole process. The process is environment-friendly and safe, the visual sense, the touch sense and the light sensation of the natural acid pickling stone can be accurately re-carved, the ceramic tile has long-acting self-cleaning and high abrasion resistance, process parameters are controllable, the ceramic tile is suitable for large-scale production of an existing production line, the high-end decoration and practical requirements are met, and the problems that a traditional stone and ceramic tile acid pickling process depends on strong acid, pollution is large, safety risks are high, and the like are solved. The problems that an existing stone grain ceramic tile can only present a plane effect, is lack of three-dimensional texture and does not have a self-cleaning function are solved.

Description

Technical Field

[0001] This invention relates to the field of glazing technology, and in particular to a glazing process for acid-free self-cleaning ceramic tiles. Background Technology

[0002] In the field of architectural ceramics decoration, the retro texture and layered luster of natural stone (such as marble and granite) after acid washing are an important choice for high-end decoration scenarios. However, the traditional acid washing process for natural stone has unavoidable defects: it relies on strong acids such as hydrofluoric acid and hydrochloric acid to corrode the stone surface. If the fluorine and chlorine waste liquid generated in the process is not properly treated, it will seriously pollute water and soil, violating environmental protection requirements. At the same time, strong acids are highly corrosive, which can not only easily burn operators, but also damage the internal crystal structure of the stone, resulting in a decrease in the strength of the stone and easy cracking and peeling problems in later use.

[0003] To replace natural stone, existing technologies mostly use high-definition inkjet printing to produce stone-patterned tiles. By printing textures on the glaze or body, the visual effect of stone is simulated. However, these tiles can only present flat patterns and lack the physical texture and gloss gradient of natural acid-washed stone (slightly shiny on raised areas and matte on recessed areas). The texture is hard and cannot meet users' needs for a three-dimensional experience of sight, touch and light.

[0004] While some improved solutions attempt to replicate the texture of stone by acid etching the ceramic glaze, they still rely on strong acids, posing ongoing environmental and safety concerns. Other solutions use dry-granule glaze to create a textured surface, but the accumulation of dry granules easily creates tiny gaps, leading to significant dirt and grime buildup and making cleaning difficult. Furthermore, existing processes generally lack self-cleaning capabilities, failing to meet the ease-of-maintenance requirements of modern homes. In conclusion, the industry urgently needs a tile glazing process that eliminates the need for acid washing, replicates the three-dimensional texture of stone, and possesses self-cleaning properties to address the environmental, safety, and functional deficiencies of existing technologies. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the existing technology and propose a glazing process for acid-free self-cleaning ceramic tiles.

[0006] To achieve the above objectives, the present invention provides a glazing process for acid-free self-cleaning ceramic tiles, comprising the following steps: S1. Biscuit firing: The ceramic tile body is placed in a kiln and heated to 800-900℃ at a heating rate of 5℃ / min. It is then held at this temperature for 2-3 hours for low-temperature biscuit firing. After cooling to room temperature, the surface ash is removed to form a biscuit fired body. S2. Application of base glaze: The base glaze material is ball-milled to a fineness of 325 mesh, deionized water is added to make a glaze slurry with a solid content of 60-65%. The glaze slurry is evenly applied to the surface of the bisque-fired body by glazing, and the thickness of the glaze layer is controlled to be 0.3-0.5 mm. Then it is dried at 120-150℃ for 15-20 minutes to form the base glaze layer. S3. Triple Digital Inkjet Texturing: A triple digital inkjet printer is used to sequentially perform inkjet printing operations on the surface of the base glaze layer: the first inkjet printer sprays base color ink, with an ink layer thickness of 5-8μm; the second inkjet printer sprays texture ink on the surface of the base color ink layer, with an ink layer thickness of 8-12μm; the third inkjet printer sprays crystal simulation ink on the surface of the texture ink layer, with an ink layer thickness of 3-5μm, ultimately forming the texture layer; S4. Digital Adhesive Dry Granule Molding: Digital adhesive is sprayed onto the textured layer surface with a positioning accuracy of ≤0.1mm using a digital mold, and the spraying thickness is 10-15μm; then, the composite functional dry granules are placed in the area covered by digital adhesive using a negative pressure suction method, and the dry granule accumulation thickness is 0.1-0.5mm. After standing for 5-10 minutes, the adhesive and dry granules are initially cured to obtain a preform with an uneven structure. S5. High-temperature slow firing: The green body with concave and convex structure is fed into the roller kiln and a stepped heating mode is adopted: from room temperature to 600℃, the heating rate is 5℃ / min; from 600 to 1100℃, the heating rate is 3℃ / min; from 1100 to 1300℃, the heating rate is 1℃ / min; after heating to 1100-1300℃, it is held for 2-3 hours, and after cooling to room temperature, the glazing process of acid-free self-cleaning ceramic tile is completed.

[0007] Preferably, the base glaze in S2 is made by mixing the following parts by weight: 25-30 parts feldspar, 15-20 parts quartz, 10-15 parts kaolin, 5-8 parts titanium dioxide matting agent, 2-4 parts zinc oxide, 2-4 parts aluminum oxide, and 3-5 parts flux.

[0008] Preferably, the flux in S2 is barium carbonate.

[0009] Preferably, the preparation method of the base color ink in S3 is as follows: by weight, 8-12 parts of inorganic ceramic pigment, 25-30 parts of water-based acrylic resin, 1-2 parts of sodium polycarboxylate, 3-5 parts of glycerol and 55-65 parts of deionized water are mixed, stirred at 800 r / min for 30 min, and then ground in a sand mill until the particle size is ≤1 μm. After filtration and degassing, the base color ink is obtained; the inorganic ceramic pigment is at least one of iron oxide or chromium oxide.

[0010] Preferably, the preparation method of the texture ink in S3 is as follows: by weight, 5-8 parts of inorganic ceramic pigment, 3-5 parts of quartz nanopowder with a particle size of 50-100nm, 20-25 parts of waterborne polyurethane resin, 0.5-1 parts of polyether modified silicone oil, 0.3-0.5 parts of organosilicon defoamer and 60-70 parts of deionized water are mixed, ultrasonically dispersed for 20min, stirred at 600r / min for 40min, and then ground in a sand mill until the particle size is ≤1μm. Then, the mixture is filtered and defoamed to obtain the texture ink; the inorganic ceramic pigment is a mixture of two or more of iron oxide, chromium oxide, cobalt oxide or titanium oxide.

[0011] Preferably, the preparation method of the crystal simulation ink in S3 is as follows: by weight, 4-6 parts of aluminum titanate microcrystalline powder with a particle size of 1-3 μm, 0.5-1 parts of pigment, 28-32 parts of water-based epoxy modified resin, 0.8-1.2 parts of hydroxyethyl cellulose, 2-3 parts of polyvinyl alcohol and 55-65 parts of deionized water are mixed, stirred at 500 r / min for 30 min, ultrasonically dispersed for 15 min, and then ground in a sand mill until the particle size is ≤1 μm. Then, the mixture is filtered and degassed to obtain the crystal simulation ink.

[0012] Preferably, the colorant is at least one of vanadium zirconium blue or chrome tin red.

[0013] Preferably, the preparation method of the digital adhesive in S4 is as follows: by weight, 40-45 parts of low molecular weight waterborne polyurethane resin, 1.5-2 parts of xanthan gum, 0.8-1.2 parts of acrylate leveling agent, 0.3-0.6 parts of polyether defoamer, 0.5-1 parts of organic amine accelerator and 45-50 parts of deionized water are mixed, stirred at 300 r / min for 30 min and then stirred at 500 r / min for 20 min, and then ground in a sand mill until the particle size is ≤1 μm, and then filtered and defoamed to obtain the digital adhesive.

[0014] Preferably, the preparation method of the composite functional dry granules in S4 is as follows: by weight, 59.5-63 parts of feldspar powder, 25.5-30.5 parts of quartz powder, 3-5 parts of barium carbonate, 2-3 parts of anatase titanium dioxide, and 0.5-1 parts of calcium stearate are mixed, and 5-7 parts of a 10% polyvinyl alcohol aqueous solution are added as a binder. The mixture is then spray-granulated to form particles with a particle size of 0.1-0.3 mm. After sieving, the particles are calcined in a muffle furnace at 600°C for 1 hour to obtain the composite functional dry granules.

[0015] Preferably, the mechanism of action of each step in the glazing process of the acid-free self-cleaning ceramic tile of the present invention is explained as follows: The initial body is a loose, compacted material with low strength and uneven water absorption, making it prone to breakage or uneven glaze application when glazed directly. Step S1 achieves pre-sintering of the body through low-temperature bisque firing: on the one hand, it allows the mineral particles to initially bond together, forming a bisque-fired body that can support subsequent processes and prevents breakage; on the other hand, it slowly removes moisture, suppresses thermal stress, and prevents cracking and deformation; at the same time, it reduces the body's glaze absorption capacity, laying the foundation for even application of the base glaze layer. After cooling, removing floating ash eliminates impurities and ensures a tight bond between the glaze and the body. In step S2, the base glaze layer is the core of the self-cleaning and acid-washed textured base. In the formula, feldspar and quartz form the glaze skeleton, ensuring density and wear resistance; kaolin enhances the stability of the glaze slurry; titanium dioxide matting agent reduces the base gloss, laying the foundation for the acid-washed matte texture; zinc oxide and aluminum oxide are combined, precipitating microcrystals at high temperatures, enhancing the glaze layer strength and providing self-cleaning active sites; barium carbonate is used as a flux to lower the glaze melting temperature; ball milling to 325 mesh ensures a fine glaze slurry, avoiding a rough glaze surface; controlling the glaze slurry solid content to 60-65% and the glaze thickness to 0.3-0.5mm ensures full glaze coverage without dripping; drying removes moisture to prevent ink bleeding, allowing the base glaze layer to initially solidify and become suitable for subsequent inkjet printing. In step S3, the visual effect of stone is replicated through inkjet printing of base color, texture, and crystals. The base color ink uses high-temperature resistant inorganic pigments for color development and water-based acrylic resin for color carrying, forming a rich stone base color; the texture ink adds 50-100nm quartz nanoparticles to simulate the rough texture of acid washing, and the 8-12μm thick ink layer enhances the texture layer through tonal differences; the crystal simulation ink uses 1-3μm aluminum titanate microcrystalline powder to simulate the mineral crystallization, and the 3-5μm thin ink layer avoids covering the texture, using only crystal shimmer to enrich the texture, ultimately forming the visual effect of natural stone; Step S4 uses physical methods instead of chemical acid etching to create a textured surface. The digital adhesive is primarily low-molecular-weight waterborne polyurethane with suitable adhesion: it can absorb dry granules and completely decompose at high temperatures without residue. Xanthan gum adjusts the viscosity and prevents the adhesive from sagging. The composite functional dry granules are made from feldspar powder and quartz powder, which can fuse with the glaze layer at high temperatures. A 10-15μm adhesive thickness ensures strong adhesion. 0.1-0.3mm dry granules are layered under negative pressure, accumulating to form 0.1-0.5mm protrusions. A 5-10 minute standing period is allowed for initial curing to prevent the dry granules from falling off. Step S5 achieves glaze shaping and functional activation through stepped heating and heat preservation. Slow heating from room temperature to 600℃ removes water and organic impurities, preventing blistering of the glaze surface; at 600-1100℃, the glaze softens and melts, and the dry particles initially fuse with the glaze layer; slow heating from 1100-1300℃ ensures the glaze is dense, and 2-3 hours of heat preservation allows the glaze layer and dry particles to fully fuse, while simultaneously creating a gloss gradient: the raised areas have a smooth glaze surface with a slightly higher gloss, while the recessed areas are enriched with titanium dioxide, resulting in a high-matte structure, replicating the acid-washed texture; finally, cooling and shaping create a glaze surface that combines self-cleaning and acid-washed textures.

[0016] The beneficial effects of this invention are: 1. This invention completely eliminates the reliance on strong acids such as hydrofluoric acid and hydrochloric acid in traditional stone and ceramic acid etching processes. The entire process uses physical methods (digital glue dry granulation) to construct the textured surface, eliminating the generation of acidic waste liquid from the source and preventing waste liquid from polluting water and soil, thus complying with national ceramic industry pollutant emission standards. At the same time, the absence of strong acid operation steps effectively prevents operators from being corroded, ensuring production safety. Furthermore, it eliminates the need to alter the glaze structure through chemical corrosion, avoiding the risk of strength reduction and cracking of the glaze layer due to acid etching, ensuring the overall integrity and stability of the ceramic tile glaze layer. From the perspectives of environmental protection, safety, and product structural stability, this invention solves the core pain points of traditional acid washing processes.

[0017] 2. This invention achieves long-lasting self-cleaning performance on tile surfaces through the synergistic design of a base glaze layer and self-cleaning components in composite functional dry granules. The titanium dioxide matting agent, zinc oxide, and aluminum oxide in the base glaze form uniformly distributed self-cleaning active sites after high-temperature firing. The anatase titanium dioxide in the composite functional dry granules further enhances this activity. Together, they efficiently photocatalytically degrade surface oil, organic matter, and other pollutants. Simultaneously, the dense glaze layer and uneven structure formed by high-temperature slow firing reduce dirt accumulation in pores and possess excellent hydrophobic properties. Stains adhere only to the surface and can be removed with simple wiping or water, significantly reducing the frequency and difficulty of daily cleaning and maintenance, thus meeting the modern home's demand for ease of maintenance.

[0018] 3. This invention achieves precise replication of the three-dimensional texture of natural acid-washed stone through a synergistic process of triple digital inkjet texturing and digital glue dry granulation. In the triple digital inkjet process, the base ink establishes the basic color tone of the stone, the texture ink outlines the details of the natural acid-washed texture, and the crystal simulation ink simulates the transparency and smoothness of mineral crystals. The three layers are superimposed to form a rich visual hierarchy. The digital glue dry granulation process constructs a regular and adaptable concave-convex structure through precise positioning and dry granule stacking. Combined with the gloss gradient formed by the stepped temperature firing (slightly brighter on the raised areas and matte on the recessed areas), it perfectly restores the three-dimensional visual, tactile, and light-sensory experience of natural acid-washed stone. Compared with the rigid texture of traditional flat inkjet tiles, the decorative effect is closer to natural stone and can meet the high requirements of high-end decoration scenarios for texture.

[0019] 4. The process parameters of this invention are clear and controllable. From the firing temperature and holding time of the ceramic body, the fineness and application thickness of the base glaze, to the ink layer thickness and positioning accuracy of triple digital inkjet printing, the spraying and stacking parameters of digital adhesive granules, and the stepped heating rate and holding time of high-temperature slow firing, a standardized control system is formed. This effectively ensures product quality consistency and reduces the defect rate during production. Furthermore, the process does not require the introduction of large-scale specialized equipment and can be adapted to existing tile production lines for upgrading. Enterprises do not need to invest heavily in equipment, facilitating rapid large-scale production and flexibly meeting production orders with different batches and texture requirements, thereby improving enterprise production efficiency and market responsiveness.

[0020] 5. This invention endows ceramic tiles with excellent durability through a scientific glaze formula and high-temperature slow-firing process. Feldspar and quartz in the base glaze form a continuous and dense glassy phase framework, while zinc oxide and aluminum oxide precipitate microcrystals at high temperatures to fill the glaze pores. Combined with the complete melting of composite functional dry granules and the glaze layer, this significantly improves the hardness and wear resistance of the glaze layer, enabling it to withstand long-term daily friction wear. The dense glaze structure also effectively isolates the penetration of acid and alkali solutions, reducing the erosion of the glaze surface by acidic and alkaline environments and minimizing problems such as loss of gloss and discoloration. Furthermore, the textured structure has no small gaps, making it less prone to dirt accumulation and structural stability, preventing it from flaking off due to long-term use. It is widely adaptable to various scenarios such as homes, commercial spaces, and public areas, extending the lifespan of the tiles and improving the product's cost-effectiveness. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments.

[0022] The raw materials used in this invention are sourced from the following sources: Feldspar, quartz, and kaolin were purchased from Shanggao Xintai Non-metallic Mineral Powder Processing Plant. Titanium dioxide matting agent was purchased from Foshan Shunde Sansheng Trading Co., Ltd. Zinc oxide was purchased from Anhui Dalin Zinc & Carbon Materials Co., Ltd. Alumina was purchased from Shanghai Yuanjiang Chemical Co., Ltd. Barium carbonate was purchased from Langfang Qianyao Technology Co., Ltd. Iron oxide, chromium oxide, cobalt oxide, and titanium oxide were purchased from Shanghai Maclean Biochemical Technology Co., Ltd. Waterborne acrylic resin was purchased from Guangdong Xidun New Material Technology Co., Ltd. Sodium polycarboxylate was purchased from Hubei Shuaiyan Ligao Biomedical Co., Ltd. Glycerol was purchased from Shanghai Maclean Biochemical Technology Co., Ltd. Quartz nanoparticles with a particle size of 50-100nm were purchased from Jiangsu Jingshengyuan New Material Technology Co., Ltd. Waterborne polyurethane resin was purchased from Guangdong Xidun New Material Technology Co., Ltd. Polyether-modified silicone oil was purchased from [unclear - likely a company name or source]. The following products were purchased from Zhuhai Xiande New Material Technology Co., Ltd.: silicone defoamer (purchased from Shandong Punio Water Treatment Technology Co., Ltd.), aluminum titanate microcrystalline powder (1-3μm particle size) (purchased from Zhejiang Yamei Nanotechnology Co., Ltd.), vanadium zirconium blue (purchased from Hunan Xinno Technology Co., Ltd.), chromium tin red (purchased from Hunan Xinno Technology Co., Ltd.), waterborne epoxy modified resin (purchased from Shandong Ruisan Chemical Technology Co., Ltd.), hydroxyethyl cellulose (purchased from Shanghai Maclean Biochemical Technology Co., Ltd.), polyvinyl alcohol (purchased from Shanghai Maclean Biochemical Technology Co., Ltd.), low molecular weight waterborne polyurethane resin (6000 molecular weight) from Guangdong Xidun New Material Technology Co., Ltd., xanthan gum (purchased from Shanghai Maclean Biochemical Technology Co., Ltd.), acrylate leveling agent (purchased from Foshan Kening New Material Technology Co., Ltd.), polyether defoamer (purchased from Shandong Punio Water Treatment Technology Co., Ltd.), organic amine accelerator (purchased from Hebi Yuanhao New Material Technology Co., Ltd.), anatase titanium dioxide (purchased from Hubei Huifu Nanomaterials Co., Ltd.), and calcium stearate (purchased from Shanghai Maclean Biochemical Technology Co., Ltd.).

[0023] Preparation Examples 1-3: Specific preparation methods for basic glazes: Preparation Example 1: The specific preparation method of the basic glaze includes the following steps: Add 250g feldspar, 150g quartz, 100g kaolin, 50g titanium dioxide matting agent, 20g zinc oxide, 20g aluminum oxide, and 30g barium carbonate to a mixer and stir until homogeneous to obtain the base glaze.

[0024] Preparation Example 2: The specific preparation method of the base glaze includes the following steps: Add 270g of feldspar, 170g of quartz, 130g of kaolin, 65g of titanium dioxide matting agent, 30g of zinc oxide, 30g of aluminum oxide, and 40g of barium carbonate to a mixer and stir until homogeneous to obtain the base glaze.

[0025] Preparation Example 3: The specific preparation method of the basic glaze includes the following steps: Add 300g of feldspar, 200g of quartz, 150g of kaolin, 80g of titanium dioxide matting agent, 40g of zinc oxide, 40g of aluminum oxide, and 50g of flux to a mixer and stir until homogeneous to obtain the base glaze.

[0026] Preparation Example 4-6: Specific preparation method of base color ink: Preparation Example 4: The specific preparation method of the base color ink includes the following steps: Mix 80g iron oxide, 250g water-based acrylic resin, 10g sodium polycarboxylate, 30g glycerol and 550g deionized water, stir at 800r / min for 30min, grind in a sand mill until the particle size is ≤1μm, and then filter to remove bubbles to obtain the base color ink.

[0027] Preparation Example 5: The specific preparation method of the base color ink includes the following steps: Mix 100g of inorganic ceramic pigment (made by mixing iron oxide and chromium oxide in a weight ratio of 1:1), 270g of water-based acrylic resin, 15g of sodium polycarboxylate, 40g of glycerin and 600g of deionized water, stir at 800r / min for 30min, then grind in a sand mill until the particle size is ≤1μm, and then filter and degas to obtain the base color ink.

[0028] Preparation Example 6: The specific preparation method of the base color ink includes the following steps: Mix 120g chromium oxide, 300g water-based acrylic resin, 20g sodium polycarboxylate, 50g glycerin and 650g deionized water, stir at 800r / min for 30min, then grind in a sand mill until the particle size is ≤1μm, and then filter to remove bubbles to obtain the base color ink.

[0029] Preparation Example 7-9: Specific preparation method of texture ink: Preparation Example 7: The specific preparation method of textured ink includes the following steps: 50g of inorganic ceramic pigment (made by mixing iron oxide and cobalt oxide in a weight ratio of 1:1), 30g of quartz nanopowder with a particle size of 50-100nm, 200g of waterborne polyurethane resin, 5g of polyether modified silicone oil, 3g of organosilicon defoamer and 600g of deionized water were mixed, ultrasonically dispersed for 20min, stirred at 600r / min for 40min and then ground in a sand mill until the particle size was ≤1μm. After filtration and degassing, texture ink was obtained.

[0030] Preparation Example 8: The specific preparation method of texture ink includes the following steps: 65g of inorganic ceramic pigment (made by mixing iron oxide, chromium oxide, cobalt oxide and titanium oxide in a weight ratio of 1:1:1:1), 40g of quartz nanopowder with a particle size of 50-100nm, 225g of waterborne polyurethane resin, 7g of polyether modified silicone oil, 4g of organosilicon defoamer and 650g of deionized water were mixed, ultrasonically dispersed for 20min, stirred at 600r / min for 40min and then ground in a sand mill until the particle size was ≤1μm. After filtration and degassing, textured ink was obtained.

[0031] Preparation Example 9: The specific preparation method of texture ink includes the following steps: 80g of inorganic ceramic pigment (made by mixing chromium oxide, cobalt oxide and titanium oxide in a weight ratio of 1:1:1), 50g of quartz nanopowder with a particle size of 50-100nm, 250g of waterborne polyurethane resin, 10g of polyether modified silicone oil, 5g of organosilicon defoamer and 700g of deionized water are mixed, ultrasonically dispersed for 20min, stirred at 600r / min for 40min and then ground in a sand mill until the particle size is ≤1μm. After filtration and degassing, texture ink is obtained. The inorganic ceramic pigment is a mixture of two or more of iron oxide, chromium oxide, cobalt oxide or iron oxide.

[0032] Preparation Examples 10-12: Specific preparation method of crystal simulation ink: Preparation Example 10: The specific preparation method of crystal simulation ink includes the following steps: 40g of aluminum titanate microcrystalline powder with a particle size of 1-3μm, 5g of vanadium zirconium blue, 280g of waterborne epoxy modified resin, 8g of hydroxyethyl cellulose, 20g of polyvinyl alcohol and 550g of deionized water were mixed, stirred at 500r / min for 30min and ultrasonically dispersed for 15min, and then ground in a sand mill until the particle size was ≤1μm. After filtration and degassing, crystal simulation ink was obtained.

[0033] Preparation Example 11: The specific preparation method of crystal simulation ink includes the following steps: 50g of aluminum titanate microcrystalline powder with a particle size of 1-3μm, 7g of pigment (vanadium zirconium blue and chromium tin red mixed in a weight ratio of 1:1), 300g of water-based epoxy modified resin, 10g of hydroxyethyl cellulose, 25g of polyvinyl alcohol and 600g of deionized water were mixed, stirred at 500r / min for 30min, ultrasonically dispersed for 15min and then ground in a sand mill until the particle size was ≤1μm. After filtration and degassing, crystal simulation ink was obtained.

[0034] Preparation Example 12: The specific preparation method of crystal simulation ink includes the following steps: 60g of aluminum titanate microcrystalline powder with a particle size of 1-3μm, 10g of chrome tin red, 320g of water-based epoxy modified resin, 12g of hydroxyethyl cellulose, 30g of polyvinyl alcohol and 650g of deionized water were mixed, stirred at 500r / min for 30min and ultrasonically dispersed for 15min, and then ground in a sand mill until the particle size was ≤1μm. After filtration and degassing, crystal simulation ink was obtained.

[0035] Preparation Examples 13-15: Preparation Method of Digital Adhesive Preparation Example 13: A specific preparation method for digital adhesive, including the following steps: 400g of low molecular weight waterborne polyurethane resin, 15g of xanthan gum, 8g of acrylate leveling agent, 3g of polyether defoamer, 5g of organic amine accelerator and 450g of deionized water were mixed, stirred at 300r / min for 30min and then at 500r / min for 20min. The mixture was then ground in a sand mill until the particle size was ≤1μm. After filtration and degassing, digital adhesive was obtained.

[0036] Preparation Example 14: A specific method for preparing digital adhesive, including the following steps: 430g of low molecular weight waterborne polyurethane resin, 17g of xanthan gum, 10g of acrylate leveling agent, 4.5g of polyether defoamer, 7g of organic amine accelerator and 475g of deionized water were mixed, stirred at 300r / min for 30min and then at 500r / min for 20min. The mixture was then ground in a sand mill until the particle size was ≤1μm. After filtration and degassing, digital adhesive was obtained.

[0037] Preparation Example 15: A specific method for preparing digital adhesive, including the following steps: 450g of low molecular weight waterborne polyurethane resin, 20g of xanthan gum, 12g of acrylate leveling agent, 6g of polyether defoamer, 10g of organic amine accelerator and 500g of deionized water were mixed, stirred at 300r / min for 30min and then stirred at 500r / min for 20min. The mixture was then ground in a sand mill until the particle size was ≤1μm. After filtration and degassing, digital adhesive was obtained.

[0038] Preparation Examples 16-18: Specific preparation methods for composite functional dry granules: Preparation Example 16: A specific method for preparing composite functional dry granules, including the following steps: 595g of feldspar powder was mixed with 255g of quartz powder, 30g of barium carbonate, 20g of anatase titanium dioxide, and 5g of calcium stearate. 50g of a 10% polyvinyl alcohol aqueous solution was added as a binder. The mixture was spray-granulated to produce particles with a diameter of 0.1-0.3mm. After sieving, the particles were calcined in a muffle furnace at 600℃ for 1 hour to obtain composite functional dry granules.

[0039] Preparation Example 17: A specific method for preparing composite functional dry granules, including the following steps: 610g of feldspar powder was mixed with 280g of quartz powder, 40g of barium carbonate, 25g of anatase titanium dioxide, and 7g of calcium stearate. 60g of a 10% polyvinyl alcohol aqueous solution was added as a binder. The mixture was spray-granulated to produce particles with a diameter of 0.1-0.3mm. After sieving, the particles were calcined in a muffle furnace at 600℃ for 1 hour to obtain composite functional dry granules.

[0040] Preparation Example 18: A specific method for preparing composite functional dry granules, including the following steps: 630g of feldspar powder was mixed with 305g of quartz powder, 50g of barium carbonate, 30g of anatase titanium dioxide, and 10g of calcium stearate. 70g of 10% polyvinyl alcohol aqueous solution was added as a binder. The mixture was spray-granulated to form particles with a diameter of 0.1-0.3mm. After sieving, the particles were calcined in a muffle furnace at 600℃ for 1 hour to obtain composite functional dry granules.

[0041] Comparative Preparation Example 1: The difference between Comparative Preparation Example 1 and Preparation Example 2 is that titanium dioxide matting agent, zinc oxide and aluminum oxide are not added, while the other components remain unchanged.

[0042] Comparative Preparation Example 2: The difference between Comparative Preparation Example 2 and Preparation Example 17 is that no anatase titanium dioxide is added, while the other components remain unchanged.

[0043] Example 1: A glazing process for acid-free self-cleaning ceramic tiles, specifically including the following steps: S1. Biscuit firing: The ceramic tile body is placed in a kiln and heated to 800℃ at a heating rate of 5℃ / min. It is then held at that temperature for 2 hours for low-temperature biscuit firing. After cooling to room temperature, the surface ash is removed to form a biscuit fired body. S2. Application of base glaze: The base glaze material prepared according to Preparation Example 1 is ball-milled to a fineness of 325 mesh, deionized water is added to make a glaze slurry with a solid content of 60%, and the glaze slurry is evenly applied to the surface of the bisque-fired body by glazing. The thickness of the glaze layer is controlled to be 0.3 mm. Then it is dried at 120°C for 15 min to form the base glaze layer. S3. Triple digital inkjet texturing: Using a triple digital inkjet printer, inkjet printing operations are performed sequentially on the surface of the base glaze layer: The first inkjet printer sprays the base color ink prepared according to Preparation Example 4, with an ink layer thickness of 5μm; the second inkjet printer sprays the texture ink prepared according to Preparation Example 7 onto the surface of the base color ink layer, with an ink layer thickness of 8μm; the third inkjet printer sprays the crystal simulation ink prepared according to Preparation Example 10 onto the surface of the texture ink layer, with an ink layer thickness of 3μm, finally forming the texture layer; S4. Digital Adhesive Dry Granule Molding: The digital adhesive prepared according to Preparation Example 13 was sprayed onto the textured layer surface with a positioning accuracy of ≤0.1mm using a digital mold, and the spraying thickness was 10μm; then, the composite functional dry granules prepared according to Preparation Example 16 were placed on the digital adhesive-covered area using a negative pressure suction method, and the dry granule accumulation thickness was 0.1mm. After standing for 5min, the adhesive and dry granules were initially cured to obtain a preform with an uneven structure. S5. High-temperature slow firing: The green body with concave and convex structure is fed into the roller kiln and a stepped heating mode is adopted: from room temperature to 600℃, the heating rate is 5℃ / min; from 600 to 1100℃, the heating rate is 3℃ / min; from 1100 to 1300℃, the heating rate is 1℃ / min; after heating to 1100-1300℃, it is held for 2 hours, and after cooling to room temperature, the glazing process of acid-free self-cleaning ceramic tile is completed.

[0044] Example 2: A glazing process for acid-free self-cleaning ceramic tiles, specifically including the following steps: S1. Bisque firing of the body: The ceramic tile body is placed in a kiln and heated to 850°C at a heating rate of 5°C / min. It is then held at this temperature for 2.5 hours for low-temperature bisque firing. After cooling to room temperature, the surface ash is removed to form a bisque fired body. S2. Application of base glaze: The base glaze material prepared according to Preparation Example 2 is ball-milled to a fineness of 325 mesh, deionized water is added to make a glaze slurry with a solid content of 63%, and the glaze slurry is evenly applied to the surface of the bisque-fired body by glazing. The thickness of the glaze layer is controlled to be 0.4 mm. Then it is dried at 135°C for 18 min to form the base glaze layer. S3. Triple digital inkjet texturing: Using a triple digital inkjet printer, inkjet printing operations are performed sequentially on the surface of the base glaze layer: The first inkjet printer sprays the base color ink prepared according to Preparation Example 5, with an ink layer thickness of 6μm; the second inkjet printer sprays the texture ink prepared according to Preparation Example 8 onto the surface of the base color ink layer, with an ink layer thickness of 10μm; the third inkjet printer sprays the crystal simulation ink prepared according to Preparation Example 11 onto the surface of the texture ink layer, with an ink layer thickness of 4μm, finally forming the texture layer; S4. Digital Adhesive Dry Granule Molding: The digital adhesive prepared according to Preparation Example 14 was sprayed onto the textured layer surface with a positioning accuracy of ≤0.1mm using a digital mold, and the spraying thickness was 13μm; then, the composite functional dry granules prepared according to Preparation Example 17 were placed on the digital adhesive-covered area using a negative pressure suction method, and the dry granule accumulation thickness was 0.3mm. After standing for 7 minutes, the adhesive and dry granules were initially cured to obtain a preform with an uneven structure. S5. High-temperature slow firing: The green body with concave and convex structure is fed into the roller kiln and a stepped heating mode is adopted: from room temperature to 600℃, the heating rate is 5℃ / min; from 600 to 1100℃, the heating rate is 3℃ / min; from 1100 to 1300℃, the heating rate is 1℃ / min; after heating to 1100-1300℃, it is held for 2.5 hours, and after cooling to room temperature, the glazing process of acid-free self-cleaning ceramic tile is completed.

[0045] Example 3: A glazing process for acid-free self-cleaning ceramic tiles, specifically including the following steps: S1. Biscuit firing: The ceramic tile body is placed in a kiln and heated to 900℃ at a heating rate of 5℃ / min. It is then held at that temperature for 3 hours for low-temperature biscuit firing. After cooling to room temperature, the surface ash is removed to form a biscuit fired body. S2. Application of base glaze: The base glaze material prepared according to Preparation Example 3 is ball-milled to a fineness of 325 mesh, deionized water is added to make a glaze slurry with a solid content of 65%, and the glaze slurry is evenly applied to the surface of the bisque-fired body by glazing. The thickness of the glaze layer is controlled to be 0.5 mm, and then dried at 150°C for 20 min to form the base glaze layer. S3. Triple Digital Inkjet Texturing: Using a triple digital inkjet printer, inkjet printing operations are performed sequentially on the surface of the base glaze layer: The first inkjet printer sprays the base color ink prepared according to Preparation Example 6, with an ink layer thickness of 8μm; the second inkjet printer sprays the texture ink prepared according to Preparation Example 9 onto the surface of the base color ink layer, with an ink layer thickness of 12μm; the third inkjet printer sprays the crystal simulation ink prepared according to Preparation Example 12 onto the surface of the texture ink layer, with an ink layer thickness of 5μm, finally forming the texture layer; S4. Digital Adhesive Dry Granule Molding: The digital adhesive prepared according to Preparation Example 15 was sprayed onto the textured layer surface with a positioning accuracy of ≤0.1mm using a digital mold, and the spraying thickness was 15μm; then, the composite functional dry granules prepared according to Preparation Example 18 were placed on the digital adhesive-covered area using a negative pressure suction method, and the dry granule accumulation thickness was 0.5mm. After standing for 10min, the adhesive and dry granules were initially cured to obtain a preform with an uneven structure. S5. High-temperature slow firing: The green body with concave and convex structure is fed into the roller kiln and a stepped heating mode is adopted: from room temperature to 600℃, the heating rate is 5℃ / min; from 600 to 1100℃, the heating rate is 3℃ / min; from 1100 to 1300℃, the heating rate is 1℃ / min; after heating to 1100-1300℃, it is held for 3 hours, and after cooling to room temperature, the glazing process of acid-free self-cleaning ceramic tile is completed.

[0046] Comparative Example 1: The difference between Comparative Example 1 and Example 2 is that step S4 is omitted, and after the texture layer is formed in step S3, it is directly sent into the roller kiln for firing.

[0047] Comparative Example 2: The difference between Comparative Example 2 and Example 2 is that the base glaze prepared according to Preparation Example 2 and the composite functional dry granules prepared according to Preparation Example 17 used in Example 2 are replaced with the base glaze prepared according to Comparative Preparation Example 1 and the composite functional dry granules prepared according to Comparative Preparation Example 2.

[0048] Comparative Example 3: The difference between Comparative Example 3 and Example 2 is that the triple digital inkjet texturing in step S3 is changed to double digital inkjet texturing, that is, the crystal simulation ink prepared according to Preparation Example 12 is not sprayed on the surface of the texture ink layer without the use of a third-stage inkjet printer.

[0049] Comparative Example 4: The difference between Comparative Example 4 and Example 2 is that step S4 is omitted. After completing step S3, the blank is immersed in a 10% hydrofluoric acid solution for 8 minutes for corrosion, then neutralized with a 5% sodium bicarbonate solution for 10 minutes, rinsed with clean water, and then subjected to step S5 for high-temperature slow firing.

[0050] Comparative Example 5: The difference between Comparative Example 5 and Example 2 is that the stepped heating mode is replaced with a uniform heating mode. Specifically, the temperature is raised directly from room temperature to 1300℃ at a uniform rate of 3℃ / min and held for 2.5 hours. After cooling to room temperature, the glazing process of the acid-free self-cleaning ceramic tile is completed.

[0051] Performance testing: 1. Stain Resistance Test: Referring to GB / T 4100-2015 "Ceramic Tiles", ceramic tile samples from Examples 1-3 and Comparative Examples 1-5 were taken, each measuring 300mm × 300mm. The surfaces were cleaned with deionized water and dried. Three common contaminants were selected: coffee (5% concentration), soy sauce (commercially available light soy sauce), and machine oil (SAE 5W-30). 0.5mL of each contaminant was dropped onto the ceramic tile surface using a pipette. The samples were left to stand for 24 hours at 25℃ and 60% relative humidity. After standing, the surface was wiped three times with a dry cloth, then wiped three times with a damp cloth (soaked in deionized water). Finally, the surface moisture was absorbed with lint-free paper. The contamination residue was observed under natural light and rated according to the stain resistance level standard: Level 5 indicates no contamination residue, Level 4 indicates very slight residue (visible upon close observation), Level 3 indicates slight residue, Level 2 indicates obvious residue, and Level 1 indicates severe residue. The experimental results are shown in Table 1.

[0052] 2. Anti-slip performance test: A pendulum friction coefficient measuring instrument (model BM-Ⅲ) was used to test the ceramic tile samples of Examples 1-3 and Comparative Examples 1-5 in a wet state (surface sprayed with 0.1 ml / cm²). 2The friction coefficient of deionized water was tested according to the EN 14411 standard. The anti-slip grade R9 corresponds to a wet friction coefficient ≥0.4, and R10 corresponds to ≥0.48. By comparing the friction coefficient obtained from the test with the standard threshold, it was determined whether the sample reached the target R9 grade. The experimental results are shown in Table 1.

[0053] 3. Self-cleaning performance test: Take ceramic tile samples from Examples 1-3 and Comparative Examples 1-5, each 100mm × 100mm in size, clean the surface with anhydrous ethanol and dry it, then uniformly coat the sample surface with 0.1ml / cm² of the self-cleaning agent. 2 Oil stains (a mixture of cooking oil and benzene, mass ratio 1:1) were placed in an ultraviolet aging chamber (wavelength 254nm, illuminance 10mW / cm²). 2 The samples were irradiated for 4 hours. The mass of the samples was weighed using a precision electronic balance (accuracy 0.0001g) before and after irradiation. The oil degradation rate was calculated as (mass of oil before irradiation - mass of residual oil after irradiation) / mass of oil before irradiation × 100%. The experimental results are shown in Table 1.

[0054] 4. Texture Simulation Test: The unevenness (height difference between protrusions and depressions) of the ceramic tile samples of Examples 1-3 and Comparative Examples 1-5 was measured using a surface profilometer (model ContourGT-K). Five areas were measured for each sample, and the average value was taken to evaluate whether the tactile texture conformed to the 0.1-0.5mm unevenness range of natural acid-washed stone. At the same time, a gloss meter (model HG60) was used to test the gloss of the protruding and depressed areas of the samples (incident angle 60°), and the gloss gradient (protruding gloss - depressed gloss) was recorded. The experimental results are shown in Table 1.

[0055] 5. Glaze Physical Properties Test: Referring to GB / T 3810.7-2016 "Test Methods for Ceramic Tiles Part 7: Abrasion Resistance of Glazed Tiles", an abrasion testing machine (model MN600) was used to test the ceramic tile samples of Examples 1-3 and Comparative Examples 1-5. The sample surface was rubbed with silicon carbide abrasive under a load of 175g and 500 revolutions. After the test, the glaze wear was observed, and the wear amount (mg) was recorded. Ceramic tile samples of Examples 1-3 and Comparative Examples 1-5, each 100mm × 100mm in size, were immersed in 5% hydrochloric acid solution and 5% sodium hydroxide solution, respectively, and left to stand at 25℃ for 24 hours. After removal, they were rinsed with deionized water and dried. The change rate of gloss before and after immersion was measured using a gloss meter: |Gloss after immersion - Gloss before immersion| / Gloss before immersion × 100%. The experimental results are shown in Table 1.

[0056] Table 1 Performance Test Results Performance Analysis: As can be seen from the experimental data in Table 1, Examples 1-3 of this invention all adopt a complete process of bisque firing of the body → application of basic glaze → triple digital inkjet printing → digital glue dry granulation → step-heating slow firing. The synergistic effect of each core link makes the ceramic tile perform excellently in terms of stain resistance, slip resistance, self-cleaning, texture, wear resistance and acid and alkali resistance, fully meeting the design goals. Among them, the process parameters of Example 2 are optimally matched within a reasonable range, the self-cleaning component is more evenly dispersed, the glaze layer is more fully melted, and the concave and convex structure and texture are more matched. Therefore, the overall performance is the best among the examples.

[0057] Example 2 exhibits five levels of anti-fouling performance, primarily due to the combined effect of synergistic self-cleaning components and physical structure adaptation: the titanium dioxide matting agent in the base glaze and the anatase titanium dioxide in the dry granules form a globally distributed self-cleaning active layer that can actively degrade organic oil stains; simultaneously, the shallow convex and wide concave structure constructed by the digital adhesive dry granules has no small gaps, so oil stains only adhere to the surface of the glaze, making it difficult for them to penetrate and hide, and they can be easily removed by wiping; comparing the comparative examples, Comparative Example 1, lacking the digital adhesive dry granule forming step and without the support of the concave and convex structure, although the flat glaze surface has self-cleaning components, oil stains are easily removed due to surface tension. The accumulation of residue reduces the stain resistance level. Comparative Example 2, due to the removal of self-cleaning components, lacks active degradation ability, making it difficult to completely remove oil stains by wiping after they adhere, resulting in a significant decrease in stain resistance. Comparative Example 4, by using uniform heating instead of stepped heating, causes a sudden escape of moisture and organic components at low temperatures, forming glaze bubbles. These bubbles easily trap dirt and grime, leading to poorer stain resistance. Comparative Example 5, by using traditional acid etching instead of digital dry particles, creates irregular micropores during the acid etching process, which become hiding places for oil stains, resulting in a weaker stain resistance than Example 2. Only Comparative Example 3, lacking only crystal simulation ink, has the same stain resistance level as Example 2, but other properties still differ.

[0058] Example 2 achieves an R10 anti-slip performance primarily due to the uniform uneven structure created by the digital adhesive dry granule molding: the dry granules are precisely positioned and controlled, resulting in unevenness within a suitable range, effectively increasing the friction area between the tile surface and the contact object. Especially in humid environments, the uneven structure can prevent water film formation and maintain a high coefficient of friction. In comparison, Comparative Example 1 lacks the digital dry granule step, resulting in a flat tile surface with a small friction area, making it prone to water film formation in humid environments, thus reducing the coefficient of friction and lowering the anti-slip level. Comparative Example 5 uses an acid etching process, where the acid etching creates… The uneven structure is irregular and the edges are rough. The unevenness in some areas is insufficient, and the overall friction coefficient is lower than that of Example 2, resulting in a reduced anti-slip level. Although Comparative Examples 2, 3, and 4 retain or partially retain the uneven structure, Comparative Example 2 has a slightly lower glaze hardness due to the lack of self-cleaning components. After long-term use, the unevenness is easily worn, resulting in poor anti-slip stability. Comparative Example 4 has uneven melting of dry particles and glaze due to uniform heating, causing some protrusions to collapse and reducing the friction coefficient. Only the anti-slip structure of Comparative Example 3 is unaffected, and its anti-slip level is close to that of Example 2. However, due to the lack of other processes, there are still differences in overall performance.

[0059] Example 2 exhibits significantly higher oil stain degradation capacity than the comparative examples. The core mechanism lies in the uniform dispersion of the self-cleaning components and sufficient high-temperature activation. Zinc oxide and aluminum oxide in the base glaze act as active carriers, promoting the uniform dispersion of anatase titanium dioxide, preventing its aggregation and deactivation, and forming sufficient active sites. During the stepped heating and slow firing process, the high-temperature stage optimizes the titanium dioxide crystal structure, enhances photocatalytic activity, and ensures complete integration of the active components with the glaze layer, fully covering the tile surface and efficiently degrading organic oil stains. In contrast, Comparative Example 2, due to the removal of the self-cleaning functional components, lacks sufficient active sites and relies solely on the adsorption of a small amount of impurities. The degradation efficiency of Comparative Example 1 was significantly reduced due to the lack of digital dry granules, resulting in the self-cleaning components being distributed only on a flat surface, reducing the contact area with oil stains and thus decreasing the degradation efficiency. In Comparative Example 4, due to uniform heating, residual organic components affected the dispersion of active components at low temperatures, while uneven melting of the glaze at high temperatures led to local aggregation of active sites, reducing the degradation efficiency. In Comparative Example 5, the acid etching process damaged some of the self-cleaning components, and the acid etching pores caused the loss of active components, resulting in a lower degradation efficiency than Example 2. Comparative Example 3 only lacked crystal simulation ink, which had no effect on the distribution and activity of active components, and its degradation efficiency was only slightly lower than that of Example 2.

[0060] Example 2 exhibits a texture highly matched to natural acid-washed stone in terms of both unevenness and gloss gradient. This is attributed to the precise digital shape control and stepped heating differentiation. Digital glue dry granule molding, through targeted spraying and negative pressure control, ensures uniform granule thickness, forming a regular and suitable uneven structure. During the stepped heating process, impurities are slowly removed at the low temperature stage to prevent glaze deformation, while the high temperature stage allows the dry granules and glaze in the raised areas to fully melt (resulting in a smoother surface and higher gloss), while the recessed areas are enriched with titanium dioxide matting agent (resulting in lower gloss), creating a clear gloss gradient. In comparison, Comparative Example 1 lacks digital dry granules, has no uneven structure, and exhibits a uniform gloss without gradient. The texture of the two examples is completely different from that of natural stone. Comparative Example 2, due to the lack of self-cleaning components (containing titanium dioxide matting agent), has a higher gloss in the recessed areas, a smaller gloss gradient, and insufficient texture. Comparative Example 4, due to uniform heating, has uneven melting of the glaze, resulting in partial collapse of the raised areas and unstable gloss in the recessed areas, with both the unevenness and gloss gradient decreasing. Comparative Example 5, due to the acid etching process, has uncontrollable unevenness and irregular edges, and the acid etching also causes the glaze to lose its overall gloss, resulting in a smaller gloss gradient. Comparative Example 3 only lacks crystal simulation ink, which does not affect the unevenness structure and gloss differentiation mechanism. The unevenness and gloss gradient are only slightly lower than those of Example 2, and the texture is similar but lacks crystal shimmer details.

[0061] Example 2 exhibits superior wear resistance compared to the comparative examples. This may be due to the synergistic effect of sufficient glaze densification and microcrystalline reinforcement. Feldspar and quartz in the base glaze are fully melted through step-heating and slow firing, forming a continuous and dense glassy phase framework. Zinc oxide and aluminum oxide precipitate microcrystals at high temperatures, filling glaze pores and enhancing glaze hardness. Simultaneously, the digital dry particles are completely integrated with the glaze layer, resulting in higher hardness in raised areas due to the added dry particles, thus improving overall wear resistance. In contrast to the comparative examples, Comparative Example 2, lacking self-cleaning components (containing microcrystalline forming agents), exhibits a glaze layer deficiency... The lack of microcrystalline reinforcement resulted in slightly higher porosity, reduced hardness, and increased wear. In Comparative Example 4, due to uniform heating, the glaze did not melt sufficiently, the glass phase skeleton was discontinuous, the glaze layer density decreased, and the wear resistance was reduced. In Comparative Example 5, due to the acid etching process, the glaze layer thickness was partially corroded and thinned, and the acid etching pores destroyed the integrity of the glaze layer, resulting in a significant reduction in wear resistance. Although Comparative Examples 1 and 3 retained some wear-resistant mechanisms, Comparative Example 1 lacked dry particle-reinforced protrusion areas, and Comparative Example 3 had a slightly thinner surface glaze due to the lack of crystalline ink, and the wear was higher than that of Example 2.

[0062] Example 2 exhibits excellent acid and alkali resistance due to the synergistic effect of a dense glaze layer and stable components. Stepped heating and slow firing allow the glaze to fully melt, forming a dense glaze layer without obvious pores, which can effectively block the penetration of acid and alkali solutions. The feldspar, quartz and other components in the base glaze are chemically stable and have low reactivity with acids and alkalis, ensuring that the glaze surface is not prone to loss of gloss, discoloration or peeling in acidic or alkaline environments. Compared with the comparative examples, Comparative Example 2, due to the absence of a microcrystal forming agent, has a slightly higher glaze layer porosity, making it easier for acid and alkali solutions to penetrate, resulting in a greater rate of change in gloss. In Comparative Example 4, the uneven melting of the glaze layer due to uniform heating resulted in the formation of tiny bubbles, which became channels for acid and alkali penetration, thus reducing the acid and alkali resistance. In Comparative Example 5, due to the acid etching process, the glaze layer had irregular pores, allowing acid and alkali solutions to penetrate the interior of the glaze layer through the pores, resulting in a significant increase in the rate of change in gloss. Although Comparative Examples 1 and 3 retained a dense glaze layer base, Comparative Example 1 lacked a dry particle-reinforced surface layer, and Comparative Example 3 had a slightly thinner surface glaze due to the absence of crystalline ink, making the surface layer more susceptible to slight damage under acid and alkali conditions. The rate of change in gloss in both examples was higher than that in Example 2.

[0063] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A glazing process for acid-free self-cleaning ceramic tiles, characterized in that, Includes the following steps: S1. Biscuit firing: The ceramic tile body is placed in a kiln and heated to 800-900℃ at a heating rate of 5℃ / min. It is then held at this temperature for 2-3 hours for low-temperature biscuit firing. After cooling to room temperature, the surface ash is removed to form a biscuit fired body. S2. Application of base glaze: The base glaze material is ball-milled to a fineness of 325 mesh, deionized water is added to make a glaze slurry with a solid content of 60-65%. The glaze slurry is evenly applied to the surface of the bisque-fired body by glazing, and the thickness of the glaze layer is controlled to be 0.3-0.5 mm. Then it is dried at 120-150℃ for 15-20 minutes to form the base glaze layer. S3. Triple Digital Inkjet Texturing: A triple digital inkjet printer is used to sequentially perform inkjet printing operations on the surface of the base glaze layer: the first inkjet printer sprays base color ink, with an ink layer thickness of 5-8μm; the second inkjet printer sprays texture ink on the surface of the base color ink layer, with an ink layer thickness of 8-12μm; the third inkjet printer sprays crystal simulation ink on the surface of the texture ink layer, with an ink layer thickness of 3-5μm, ultimately forming the texture layer; S4. Digital Adhesive Dry Granule Molding: Digital adhesive is sprayed onto the textured layer surface with a positioning accuracy of ≤0.1mm using a digital mold, and the spraying thickness is 10-15μm; then, the composite functional dry granules are placed in the area covered by digital adhesive using a negative pressure suction method, and the dry granule accumulation thickness is 0.1-0.5mm. After standing for 5-10 minutes, the adhesive and dry granules are initially cured to obtain a preform with an uneven structure. S5. High-temperature slow firing: The green body with concave and convex structure is fed into the roller kiln and a stepped heating mode is adopted: from room temperature to 600℃, the heating rate is 5℃ / min; from 600 to 1100℃, the heating rate is 3℃ / min; from 1100 to 1300℃, the heating rate is 1℃ / min; after heating to 1100-1300℃, it is held for 2-3 hours, and after cooling to room temperature, the glazing process of acid-free self-cleaning ceramic tile is completed.

2. The glazing process for acid-free self-cleaning ceramic tiles according to claim 1, characterized in that, The base glaze in S2 is made by mixing the following parts by weight: 25-30 parts feldspar, 15-20 parts quartz, 10-15 parts kaolin, 5-8 parts titanium dioxide matting agent, 2-4 parts zinc oxide, 2-4 parts aluminum oxide, and 3-5 parts flux; the flux is barium carbonate.

3. The glazing process for acid-free self-cleaning ceramic tiles according to claim 1, characterized in that, The preparation method of the base color ink in S3 is as follows: by weight, 8-12 parts of inorganic ceramic pigment, 25-30 parts of water-based acrylic resin, 1-2 parts of sodium polycarboxylate, 3-5 parts of glycerol and 55-65 parts of deionized water are mixed, stirred at 800 r / min for 30 min, and then ground in a sand mill until the particle size is ≤1 μm. After filtration and degassing, the base color ink is obtained.

4. The glazing process for acid-free self-cleaning ceramic tiles according to claim 3, characterized in that, The inorganic ceramic colorant is at least one of iron oxide or chromium oxide.

5. The glazing process for acid-free self-cleaning ceramic tiles according to claim 1, characterized in that, The preparation method of the texture ink in S3 is as follows: by weight, 5-8 parts of inorganic ceramic pigment, 3-5 parts of quartz nanopowder with a particle size of 50-100nm, 20-25 parts of waterborne polyurethane resin, 0.5-1 parts of polyether modified silicone oil, 0.3-0.5 parts of organosilicon defoamer and 60-70 parts of deionized water are mixed, ultrasonically dispersed for 20min, stirred at 600r / min for 40min, and then ground in a sand mill until the particle size is ≤1μm. After filtration and degassing, the texture ink is obtained.

6. The glazing process for acid-free self-cleaning ceramic tiles according to claim 5, characterized in that, The inorganic ceramic colorant is a mixture of two or more of iron oxide, chromium oxide, cobalt oxide, or titanium oxide.

7. The glazing process for acid-free self-cleaning ceramic tiles according to claim 1, characterized in that, The preparation method of the crystal simulation ink in S3 is as follows: by weight, 4-6 parts of aluminum titanate microcrystalline powder with a particle size of 1-3μm, 0.5-1 parts of pigment, 28-32 parts of water-based epoxy modified resin, 0.8-1.2 parts of hydroxyethyl cellulose, 2-3 parts of polyvinyl alcohol and 55-65 parts of deionized water are mixed, stirred at 500r / min for 30min, ultrasonically dispersed for 15min, and then ground in a sand mill until the particle size is ≤1μm. After filtration and degassing, the crystal simulation ink is obtained.

8. The glazing process for acid-free self-cleaning ceramic tiles according to claim 7, characterized in that, The colorant is at least one of vanadium zirconium blue or chrome tin red.

9. The glazing process for acid-free self-cleaning ceramic tiles according to claim 1, characterized in that, The preparation method of the digital adhesive in S4 is as follows: by weight, 40-45 parts of low molecular weight waterborne polyurethane resin, 1.5-2 parts of xanthan gum, 0.8-1.2 parts of acrylate leveling agent, 0.3-0.6 parts of polyether defoamer, 0.5-1 parts of organic amine accelerator and 45-50 parts of deionized water are mixed, stirred at 300 r / min for 30 min and then stirred at 500 r / min for 20 min. After stirring, the mixture is ground in a sand mill until the particle size is ≤1 μm. Then, it is filtered and defoamed to obtain the digital adhesive.

10. The glazing process for acid-free self-cleaning ceramic tiles according to claim 1, characterized in that, The preparation method of the composite functional dry granules in S4 is as follows: by weight, 59.5-63 parts of feldspar powder, 25.5-30.5 parts of quartz powder, 3-5 parts of barium carbonate, 2-3 parts of anatase titanium dioxide, and 0.5-1 parts of calcium stearate are mixed, and 5-7 parts of 10% polyvinyl alcohol aqueous solution are added as a binder. The mixture is then spray-granulated to form particles with a particle size of 0.1-0.3 mm. After sieving, the particles are calcined in a muffle furnace at 600℃ for 1 hour to obtain the composite functional dry granules.

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