Ultrathin dry-hanging ceramic plate and preparation method thereof

Abstract

The invention discloses an ultrathin dry-hanging ceramic plate and a preparation method thereof. The ultrathin dry-hanging ceramic plate is prepared from the following raw materials: kaolin, potassium feldspar, quartz sand, an organic sintering aid and an organic impregnation liquid. The preparation method comprises the following steps: 1) pretreating raw materials; 2) mixing and granulating; 3) molding and pressing; 4) sintering; (5) post-treatment; by designing the organic sintering aid and the organic impregnation liquid, the strength of the green body is enhanced before sintering; the sintering temperature is reduced during sintering; dipping is performed after firing, so that water vapor-sensitive self-repairing capacity is achieved, and the product performance and the service life are greatly improved. The obtained ultra-thin dry-hanging ceramic plate is formed by compounding natural mineral raw materials and functional additives, the thickness can be controlled to range from 3 mm to 6 mm, the thickness deviation does not exceed 0.2 mm, and the ultra-thin dry-hanging ceramic plate is high in strength and toughness, has certain crack self-repairing capacity, is simple in preparation process and has the possibility of large-scale production; a new method and thought are provided for preparation of the ultra-thin dry-hanging ceramic plate.

Description

Technical Field

[0001] This invention relates to the field of dry-hanging terracotta panels, and more particularly to an ultra-thin dry-hanging terracotta panel and its preparation method. Background Technology

[0002] Dry-hanging terracotta panels are a type of building curtain wall material made primarily of natural clay, formed under high pressure and sintered at high temperature. They are directly fixed to the exterior of a building using a metal hanging system, eliminating the need for mortar adhesion.

[0003] The traditional production process of dry-hanging terracotta panels is as follows:

[0004] Raw materials -- Raymond mill -- powder silo -- electronic automatic batching system -- twin-shaft mixer -- chain plate mud silo -- twin-shaft high-intensity mixer -- planetary mixer with water addition -- vacuum extruder -- automatic cutting -- five-layer roller drying -- intensified drying kiln -- pre-roller kiln firing -- edge grinding and packaging. However, this production process will face challenges when producing ultra-thin ceramic panels:

[0005] Insufficient strength of the green body - the particle size of the raw materials used is too large and uneven. After the green body is formed, when the thickness is relatively thin, stress concentration is likely to occur, making the green body too brittle and prone to cracking.

[0006] Extrusion cracks are prone to occur when the surface material is subjected to large friction and additional tensile stress. When the instantaneous stress exceeds its tensile strength, extrusion cracks are generated. Under the action of external force, the cracks extend from the surface to fracture. The impact of extrusion cracks is particularly obvious for ultra-thin dry-hanging terracotta panels.

[0007] Insufficient dimensional accuracy – Traditional ceramic slabs are over 15mm thick, with thickness fluctuations of around 0.5mm. For ultra-thin ceramic slabs, this error fluctuation is too large.

[0008] Meanwhile, as a decorative material that is exposed to the outdoors for a long time, ultra-thin dry-hanging terracotta panels are more prone to cracking and fading than ordinary terracotta panels.

[0009] In summary, to produce an ultra-thin dry-hanging terracotta panel, efforts should be made to enhance the strength of the blank, eliminate extrusion cracks, increase dimensional accuracy, and possess a certain degree of self-healing capability. Summary of the Invention

[0010] The purpose of this invention is to address the shortcomings of existing technologies by proposing an ultra-thin dry-hanging ceramic panel and its preparation method.

[0011] To achieve the above objectives, the present invention adopts the following technical solution:

[0012] An ultra-thin dry-hanging terracotta panel comprises the following raw materials in parts by weight:

[0013] 40-50 parts kaolin; 22-28 parts potassium feldspar; 28-32 parts quartz sand; organic sintering aid; organic impregnation solution;

[0014] The organic sintering aids specifically include: 0.5-0.7 parts of acrylic acid-maleic acid copolymer; 0.15-0.25 parts of 3-aminopropyltriethoxysilane; 0.12-0.18 parts of hydroxyethyl cellulose; 0.03-0.07 parts of aluminum citrate; 0.42-0.72 parts of anhydrous ethanol; and 0.98-1.68 parts of deionized water.

[0015] The organic impregnation solution specifically includes: 0.54-0.66 parts of aminated SiO2-TiO2 hybrid sol; 0.72-0.88 parts of microencapsulated dodecyltrimethoxysilane; 9-11 parts of methyltriethoxysilane; 1.8-2.2 parts of γ-glycidyl etheroxypropyltrimethoxysilane; 0.18-0.22 parts of aluminum acetylacetonate; 0.45-0.55 parts of polyether siloxane; 1.35-1.65 parts of a 1% (w / w) carboxylated carbon nanotube dispersion; 31.5-38.5 parts of anhydrous ethanol; and 40.5-49.5 parts of deionized water.

[0016] Preferably, the organic sintering aid is prepared as follows:

[0017] Prepare a mixed solvent by mixing deionized water and anhydrous ethanol at a volume ratio of 7:3. Adjust the pH to 4.5-5.0 with 0.1 mol / L HCl / NaOH aqueous solution. Take 90% of the mixed solvent, first add hydroxyethyl cellulose (HEC), and disperse by stirring at 500 rpm for 30 min in a 40°C water bath. Then add acrylic acid-maleic acid copolymer (MA / AA), and stir at 500 rpm for 15 min. Finally, add aluminum citrate and stir for 15 min to obtain the main solution.

[0018] 3-Aminopropyltriethoxysilane (APTES) was pre-hydrolyzed alone in 10% solvent at 50°C for 1 hour, and then slowly added dropwise to the main solution at a rate of 1 mL / min. The solution was then circulated three times using a high-pressure homogenizer at 60 MPa, and finally filtered through a 0.45 μm microporous membrane to obtain the organic sintering aid.

[0019] Preferably, the organic impregnation solution is prepared as follows:

[0020] ① Preparation of aminated SiO2-TiO2 hybrid sol

[0021] TEOS was mixed with anhydrous ethanol at a volume ratio of 1:20 and stirred at 25°C for 10 minutes. HNO3 was slowly added dropwise to adjust the pH to 2. The mixture was stirred at 500 rpm for 2 hours in a 40°C water bath to form a transparent SiO2 sol. Tetrabutyl titanate (TBOT) was mixed with anhydrous ethanol at a volume ratio of 1:10 to obtain a TBOT solution, which was then kept in an ice bath at 4°C for later use.

[0022] The SiO2 sol was heated to 60°C, and a TBOT solution was slowly added, wherein the molar ratio of TEOS to TBOT was 3:1; the mixture was stirred at 100 rpm for 3 hours, and the pH was maintained at 2 ± 0.5.

[0023] Add 3-aminopropyltriethoxysilane APTES, wherein the molar ratio of TEOS to APTES is 1:5; continue the reaction for 1 hour to introduce amino functional groups and obtain an aminated SiO2-TiO2 hybrid sol solution; allow the aminated SiO2-TiO2 hybrid sol solution to stand at room temperature for 12 hours to allow the polycondensation reaction to be complete.

[0024] The sol was placed in a dialysis bag and dialyzed in deionized water for 48 hours; then centrifuged at 5000 rpm for 10 minutes and the supernatant was collected, which is the aminated SiO2-TiO2 hybrid sol.

[0025] ② Preparation of microencapsulated dodecyltrimethoxysilane

[0026] Microencapsulated dodecyltrimethoxysilane was prepared using the sol-gel method at a constant temperature of 40°C. Dodecyltrimethoxysilane was added to a mixed solution of dichloromethane and deionized water and stirred at 300 rpm until homogeneous. Alkylphenol polyoxyethylene ether OP-10 and ammonia were added sequentially. TEOS was then slowly added dropwise to the mixture. After reacting for 1 hour, MTES was added dropwise, and the reaction was continued for 4 hours. The mixture was then cooled to room temperature, washed with water and ethanol, and dried at 85°C to obtain a white powder, i.e., microencapsulated dodecyltrimethoxysilane. The mass ratio of dodecyltrimethoxysilane, OP-10, DTMS, TEOS, dichloromethane, and deionized water was 5:0.01:0.4:1:20:50.

[0027] ③Prepare the impregnation solution

[0028] Anhydrous ethanol and deionized water were added to the reaction vessel and stirred at 120 rpm. Methyltriethoxysilane (MTES) and γ-glycidoxypropyltrimethoxysilane (GPTMS) were slowly added at a dropping rate of 1 kg / min. The temperature was raised to 50 °C, and the pH was adjusted to 4.8 ± 0.2 with 0.01 mol / L HCl aqueous solution. The reaction was maintained at this temperature for 2 h to obtain a pre-hydrolyzed silane solution. The mass ratio of anhydrous ethanol, deionized water, MTES, and GPTMS was 27-33:40.5-49.5:9-11:1.8-2.2.

[0030] Aminated SiO2-TiO2 hybrid sol and carboxylated carbon nanotube dispersion were mixed and transferred into an ultrasonic bath. Circulating cooling water was turned on, and the ultrasonic parameters were set as follows: amplitude: 60%; probe diameter: Φ20mm; immersion depth: 1 / 3 of the liquid surface. After ultrasonic treatment, the particle size distribution D90 ≤ 100nm was detected. Nanoparticle dispersion was obtained through ultrasonic dispersion. The mass ratio of aminated SiO2-TiO2 hybrid sol to carboxylated carbon nanotube dispersion was 0.54-0.66:1.35-1.65.

[0031] Cool the pre-hydrolyzed silane solution to 40°C and add the nano-dispersion; slowly add a 4% (w / w) aluminum acetylacetonate ethanol solution while stirring at 800 rpm; the mass ratio of the pre-hydrolyzed silane solution, nano-dispersion and aluminum acetylacetonate ethanol solution is 78.3-95.7:1.8-2.2:0.68-5.72.

[0032] After stirring at 800 rpm and cooling to 25°C, polyether siloxane (PES) and microencapsulated dodecyltrimethoxysilane (DTS) are added sequentially; the mass ratio of PES to DTS is 0.45-0.55: 0.72-0.88.

[0033] Switch to planetary stirring mode and set the rotation speed to 30 rpm for revolution and 60 rpm for rotation; after aging in a nitrogen atmosphere for 48 hours, an organic impregnation solution is obtained.

[0034] Preferably, the thickness of the ceramic slab is 3-6 mm.

[0035] A method for preparing an ultrathin dry-hanging ceramic slab includes the following steps:

[0036] S1. Raw material pretreatment

[0037] The Neptune FX series ultra-fine classifying hydrocyclones are used to classify raw materials such as kaolin, potassium feldspar, and quartz sand.

[0038] S2, Mixed Granulation

[0039] Kaolin, potassium feldspar, and quartz sand are loaded into a high-strength nylon mixing tank;

[0040] Organic sintering aids were added to the mixing tank using an atomizing spray device with a nozzle diameter of 0.3 mm, a spray pressure of 0.4 MPa, and a spray angle of 45°. The three-dimensional motion of the mixing tank was set to 10 rpm revolution and 25 rpm rotation, with a motion time of 30 min, to obtain the raw material mixture.

[0041] Adding organic sintering aids to the mixing tank using an atomizing spray device can ensure that the organic sintering aids are evenly dispersed in the raw materials, thereby improving the uniformity of the mixed raw materials.

[0042] The raw material mixture is spray-dried using a centrifugal spray drying tower. Specific parameter settings are as follows:

[0043] The feed pump pressure is 1.2 MPa;

[0044] Inlet temperature is controlled in stages: 320℃ at the top of the tower, 280℃ in the middle of the tower, and 110℃ at the bottom of the tower.

[0045] The negative pressure of the cyclone separator is maintained at 1500Pa. After the product passes through a 40-mesh sieve, a mixed raw material is obtained. The moisture content of the mixed raw material is determined by an infrared rapid moisture analyzer and collected for later use.

[0046] S3, Molding and Pressing

[0047] A tungsten carbide hard alloy mold with a hardness of HRA≥90 is used. The surface of the mold cavity is mirror polished to achieve a roughness Ra≤0.05μm. The mold cavity is cleaned with acetone and then sprayed with polytetrafluoroethylene emulsion. This ensures the wear resistance and demolding performance of the mold, and improves the forming quality and surface finish of the ceramic slab.

[0048] A spiral feeder at 18 rpm, combined with an ultrasonic vibrating screen at 28 kHz, is used to ensure that the mixed raw materials are evenly filled into the mold cavity.

[0049] The mixed raw materials are pressed using a YT-RS series hot press to obtain a green body;

[0050] Press parameters for pressing mixed raw materials:

[0051] Pre-compression stage: The pressure is increased from 0 to 5MPa at a pressurization rate of 5MPa / s, the pressure is vented once, and the pressure is maintained for 1.5s;

[0052] During the main pressure stage, the pressure is increased from 5MPa to 35MPa at a pressurization rate of 3MPa / s, and held for 8s. At pressures of 20MPa and 35MPa, the pressure is vented once each.

[0053] Decompression phase:

[0054] The pressure was reduced from 35 MPa to 20 MPa at a rate of 15 MPa / s;

[0055] The pressure was reduced from 20 MPa to 8 MPa at a rate of 12 MPa / s;

[0056] The pressure was reduced from 8 MPa to complete depressurization at a rate of 8 MPa / s;

[0057] Compared to extrusion molding, dry pressing allows for more precise thickness control and is more suitable for producing small-sized, highly flat ultra-thin ceramic slabs.

[0058] The green billets were placed in a constant temperature and humidity chamber at 30±2℃ and 60±5%RH, and after standing for 12 hours, they were transferred to a chain drying kiln. The chain drying kiln was controlled in three zones:

[0059] Zone 1: Temperature set at 80℃, humidity controlled at 40%RH, wind speed at 1.5m / s, for 20 minutes;

[0060] Zone 2: Temperature set at 105℃, humidity controlled at 25%RH, wind speed at 3m / s, for 40 minutes;

[0061] Zone 3: Temperature set at 60℃, natural humidity, wind speed at 4.5m / s, for 10 minutes;

[0062] Drying is complete to obtain a dry blank;

[0063] S4, sintering

[0064] Cordierite pads are used, and an aluminum oxide isolation layer with a thickness of 0.1mm is pre-sprayed. The blanks are loaded with blanks, and the longitudinal spacing between the blanks is 20mm, and the transverse spacing is 1.2 times the width of the blank.

[0065] The dry blank is sintered at the following temperature:

[0066] The heating rate is 2℃ / min, from room temperature to 200℃;

[0067] Heating rate 1℃ / min, from 200℃ to 500℃

[0068] The heating rate is 5℃ / min, from 500℃ to 900℃;

[0069] The heating rate is 2℃ / min, from 900℃ to 1120℃;

[0070] Keep warm at 1120℃ for 30 minutes;

[0071] The cooling rate is 20℃ / min, and the temperature drops to 700℃.

[0072] The temperature was reduced to room temperature at a rate of 5℃ / min to obtain a rough ceramic slab blank.

[0073] During sintering, kaolin dehydrates to form mineral phases such as mullite and cristobalite, while potassium feldspar decomposes to generate potassium and silicate ions. Quartz sand reacts with kaolin and potassium feldspar to form mullite and other mineral phases. These reactions promote the densification of the raw materials during sintering, reduce porosity, and improve the strength and toughness of the terracotta panels. Organic sintering aids can lower the sintering temperature during the sintering process, promote the melting and reaction of the raw materials, and further improve the densification of the terracotta panels.

[0074] S5, Post-processing

[0075] S5.1 Vacuum impregnation:

[0076] The terracotta blanks were placed into a pressure-resistant container, and a rotary vane vacuum pump was used to evacuate the container to a vacuum level of 0.095 MPa. The container was preheated at 110°C for 30 minutes to remove surface adsorbed water, and then impregnated to obtain impregnated blanks. The program was set as follows:

[0077] Evacuate to -0.095 MPa and hold for 15 minutes;

[0078] Inject the organic impregnation solution, pressurize to 0.4 MPa, maintain the pressure for 25 minutes, and then drain the solution;

[0079] After draining, centrifuge at 800 rpm for 2 minutes to remove the liquid;

[0080] Record the mass of the terracotta slab blank and the impregnated blank, and calculate the weight gain rate.

[0081]

[0082] The organic impregnation solution contains components such as methyltriethoxysilane and nano-silica sol, which can penetrate into the internal pores of the ceramic slab. During the thermosetting process, a hydrolysis-condensation reaction occurs, forming a uniform silicon-oxygen network structure. This silicon-oxygen network structure can fill the pores inside the ceramic slab, improving its strength, wear resistance, and corrosion resistance. It can also improve the surface properties of the ceramic slab, giving it better gloss and hardness.

[0083] S5.2, Thermosetting:

[0084] A tunnel curing oven is used to heat-cure the impregnated blanks. The program is set as follows:

[0085] The heating rate was 5℃ / min, the temperature was increased from room temperature to 180℃, the holding time was 40min, and the atmosphere was air.

[0086] The heating rate was 2℃ / min, from 180℃ to 300℃, and the holding time was 90min. The atmosphere was nitrogen.

[0087] The cooling rate is 3℃ / min, reducing the temperature from 300℃ to room temperature through forced air convection;

[0088] After thermosetting, a thermoset blank is obtained;

[0089] S5.3 Surface Finishing

[0090] A five-axis linkage polishing machine with diamond grinding wheels is used for finishing the surface of a thermosetting blank. The program is set as follows:

[0091] Rough grinding stage: Use a 150# grinding wheel at a speed of 2500 rpm and a feed rate of 1.2 m / min for rough grinding. This stage is cooled by water.

[0092] Semi-finish grinding stage: Use a 400# grinding wheel at a speed of 3500 rpm and a feed rate of 0.8 m / min for semi-finish grinding. This stage is cooled by mist cooling.

[0093] Fine polishing stage: Use a 3000# grinding wheel at a speed of 5000 rpm and a feed rate of 0.3 m / min for fine polishing. This stage is dry polishing without cooling.

[0094] After fine grinding, the product is obtained: ultra-thin dry-hanging terracotta panels.

[0095] Preferably, for kaolin grading, the particle size distribution of kaolin needs to be controlled to D90 < 10 μm and 4 μm < D50 < 6 μm, iron impurities need to be removed, and the Fe2O3 content needs to be < 0.5%; for potassium feldspar grading, the particle size distribution of potassium feldspar needs to be controlled to D90 < 15 μm and 5 μm < D50 < 8 μm; for quartz sand grading, the particle size distribution of quartz sand needs to be controlled to D90 < 25 μm and 10 μm < D50 < 15 μm; after grading, kaolin, potassium feldspar, and quartz sand are dried in an oven at 105℃ until the moisture content is < 1%.

[0096] Grading kaolin, controlling particle size distribution, removing iron impurities, and drying the raw material to a moisture content of <1% are all measures that ensure the purity and particle size uniformity of the raw material, thereby improving the quality and performance of the terracotta panels. Controlling the particle size distribution of kaolin helps improve the density and strength of the terracotta panels, while removing iron impurities prevents color differences and defects from occurring during the sintering process.

[0097] Preferably, the moisture content of the mixed raw materials produced by spray drying is controlled at 5.5%-6.2%.

[0098] Preferably, the thickness of the fabric formed by dry pressing is controlled at 2.8-3.2 times the forming thickness.

[0099] Preferably, the weight gain rate of the impregnation treatment is controlled within 1.8%-2.2%.

[0100] During sintering, kaolin dehydrates to form mineral phases such as mullite and cristobalite, while potassium feldspar decomposes to generate potassium ions and silicate ions. Quartz sand reacts with kaolin and potassium feldspar to form mullite and other mineral phases. These reactions promote the densification of the raw materials during sintering, reduce porosity, and improve the strength and toughness of the terracotta panels.

[0101] Acrylic acid-maleic acid copolymer exhibits strong dispersing properties. The acrylic acid-maleic acid copolymer molecular chains form a protective layer on the particle surface. When particles approach each other, the steric hindrance between the molecular chains hinders particle aggregation, improving the uniformity of the mixed raw materials and enhancing the strength and toughness of the terracotta panels. The hydration of hydroxyethyl cellulose forms a three-dimensional gel network, preventing the deposition of some raw materials in the mixture.

[0102] During sintering, before 400℃, the carboxyl groups (-COOH) of the acrylic acid-maleic acid copolymer form a hydrogen bond network with the hydroxyl groups (-OH) on the surface of the clay, which improves the bending strength of the green body.

[0103] The silanol produced by the hydrolysis of the silane structure of γ-aminopropyltriethoxysilane reacts with the particle surface, increasing the stability of the green body.

[0104] NH2(CH2)3Si(OC2H5)3+H2O→NH2(CH2)3Si(OC2H5)2(OH)+C2H5OH

[0105] Si-OH + Al-OH (kaolin) → Si-O-Al + H2O

[0106] At 400℃-800℃, hydroxyethyl cellulose, acrylic acid-maleic acid copolymer, and γ-aminopropyltriethoxysilane decompose upon heating, producing nanoscale carbon particles.

[0107] The decomposition products of aluminum citrate (Al2O3 nanoclusters) form a eutectic with potassium feldspar.

[0108] The K2O-Al2O3-SiO2 system produces a eutectic phenomenon, which lowers the melting point of the mixture (by about 80°C), promotes the early formation of the liquid phase, and is beneficial to the uniformity and density of the green body.

[0109] At 800℃-1120℃, the organic additives decompose the residual nano-carbon particles, which serve as nucleation sites, thereby increasing the growth rate of mullite (3Al2O3·2SiO2) whiskers and promoting grain size homogenization. Silane-derived SiO2 clusters form enrichment zones at the grain boundaries, which accelerate sintering by reducing the local glass phase viscosity, promoting particle rearrangement and mass transfer processes.

[0110] In the impregnation solution, the SiO2 in the aminated SiO2-TiO2 hybrid sol provides hardness and strength to the ceramic slab, while the TiO2 provides ultraviolet shielding, adding anti-aging function to the ceramic slab. The amino group (-NH2) reacts with the hydroxyl group on the surface of the ceramic slab to form chemical bonds, enhancing the interfacial bonding force.

[0111] The added carboxylated carbon nanotubes (CNTs) are dispersed in the impregnation solution, filling microcracks and improving the impact resistance and toughness of the ceramic slab.

[0112] MTES hydrolysis and condensation form a three-dimensional silicon-oxygen network (Si-O-Si), filling the pores of the ceramic plate and improving its density. The epoxy group (-CH2-CHO-CH2) of γ-glycidyl etheroxypropyltrimethoxysilane (GPTMS) reacts with the surface of the ceramic plate, enhancing interfacial bonding and improving chemical corrosion resistance.

[0113] Microencapsulated dodecyltrimethoxysilane can release DTMS by reacting with moisture in the air after cracks appear in the material. The DTMS spreads evenly in the gel network, undergoes a chemical reaction, and fills the cracks, giving the invention a certain degree of self-healing ability. DTMS repairs cracks through the following reactions:

[0114] CH3O-Si-(CH2)3-CH3+H20→Si-OH+CH3OH

[0115] DTMS hydrolyzes to produce silanol (Si-OH) and methanol (CH3OH). The silanol forms a hydrophobic repair layer through a condensation reaction, while the methanol evaporates.

[0116] Si-OH + Si-OH → Si-O-Si + H₂O

[0117] Silanol condenses to form silicon-oxygen bonds (Si-O-Si), and due to the long-chain structure of DTMS itself, it constructs a hydrophobic network at the crack, filling and sealing the crack. Furthermore, the newly generated silanol reacts with the hydroxyl groups (-OH) on the ceramic panel surface to form chemical bonds (Si-O-ceramic panel), enhancing the adhesion of the repair layer. DTMS can hydrolyze and condense at room temperature without additional heating, making it suitable for outdoor environments in building curtain walls. The repaired area is hydrophobic (contact angle > 90°), preventing moisture penetration and secondary cracking. In this process, aluminum acetylacetonate acts as a catalyst for silane hydrolysis and condensation, significantly increasing the speed of DTMS crack repair and substantially improving the long-term service performance of ultra-thin ceramic panels in complex environments.

[0118] Compared with the prior art, the beneficial effects of the present invention are:

[0119] This invention utilizes the eutectic system formed by aluminum citrate and potassium feldspar during sintering to significantly reduce the sintering temperature of traditional ceramic panels from over 1200℃ to 1120℃. Furthermore, the Si and Al in the ceramic panels can fill the voids created by the organic pore-forming agent, improving the density of the ceramic panels and maintaining high flexural strength with a relatively small thickness.

[0120] This invention also utilizes an organic impregnation solution to perform vacuum impregnation treatment on the ceramic slab blank. The aminated SiO2-TiO2 hybrid sol and carbon nanotubes contained in the impregnation solution can further strengthen the ceramic slab and form a coating containing microencapsulated dodecyltrimethoxysilane on the surface of the ceramic slab.

[0121] The silicon-titanium sol and silane coupling agent penetrate into the pores of the ceramic slab blank. After high-temperature hardening, they form a cross-linked Si-O or Ti-O network structure, making the ceramic denser and significantly increasing its strength. Before heat curing, SiO2 is attached to the ceramic slab in the form of a sol, and the microcapsules are also evenly spread on the surface of the ceramic slab along with the sol. After heat curing, the shell of the microcapsule forms silicon-oxygen bonds with the main body of the ceramic slab, and is then wrapped by the dehydrated hybrid sol. The microcapsules are embedded on the surface of the ceramic slab, forming a hydrophobic protective layer on the surface of the dry blank.

[0122] When water penetrates the ceramic substrate or cracks appear in the ceramic substrate, the microcapsule shell swells and releases DTMS. DTMS hydrolyzes to generate silanol (Si-OH) and methanol (CH3OH). The silanol forms a hydrophobic repair layer through a condensation reaction, while the methanol evaporates.

[0123] Silanols condense to form silicon-oxygen bonds (Si-O-Si), and due to the long-chain structure of dodecyltrimethoxysilane itself, a new hydrophobic network is constructed at the crack, filling and sealing the crack. In addition, the newly generated silanols will also react with the hydroxyl groups (-OH) on the surface of the ceramic plate to form chemical bonds (Si-O-ceramic plate), enhancing the adhesion of the repair layer.

[0124] In summary, this invention uses organic sintering aids and organic impregnation liquid, combined with dry pressing technology, to solve the problems of insufficient strength, excessive brittleness, easy extrusion cracks, and insufficient dimensional accuracy of ultra-thin dry-hanging ceramic products. It also enables the ceramic slab to have a self-healing function, resulting in ultra-thin dry-hanging ceramics with a thickness of 3-6mm and high strength. Attached Figure Description

[0125] Figure 1 This invention provides a production flow diagram for producing an ultra-thin dry-hanging ceramic panel. Detailed Implementation

[0126] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0127] The purity and manufacturers of the various drugs used in the experiment are shown in Table 1.

[0128] Table 1. Raw Material Drug Information

[0129] Raw material name Specification Manufacturer Kaolin packing grade Shandong Xinheng Chemical Co., Ltd. Potassium feldspar 800-1000 mesh Qiyuan (Guangdong) Pharmaceutical & Chemical Co., Ltd. Quartz sand 800-1000 mesh Qianshi Environmental Protection Technology (Yichang) Co., Ltd. Acrylic acid-maleic acid copolymer Industrial grade Tianjin Xiens Biochemical Technology Co., Ltd. 3-Aminopropyltriethoxysilane Industrial grade Jiangxi Yikai Industrial Co., Ltd. Hydroxyethyl cellulose Industrial grade Tianjin Xiens Biochemical Technology Co., Ltd. Aluminum citrate Industrial grade Hubei Hengjie Chemical Co., Ltd. Anhydrous ethanol Industrial grade Shanghai McLean Biochemical Technology Co., Ltd. Methyltriethoxysilane Industrial grade Suzhou Sisu New Materials Co., Ltd. γ-glycidoxypropyltrimethoxysilane Industrial grade Shanghai Xinyu Biotechnology Co., Ltd. Carboxylated carbon nanotube dispersion Industrial grade Condis Chemical (Hubei) Co., Ltd. Aluminum acetylacetonate Industrial grade Wuhan Yuqing Jiaheng Pharmaceutical Co., Ltd. Polyether modified siloxane Industrial grade Hubei Zhonglong Kangcheng Fine Chemical Co., Ltd. dodecyltrimethoxysilane Industrial grade Huangshan Jiahe Organosilicon Technology Co., Ltd. Ethyl silicate Industrial grade Zhangjiagang Longtai Chemical Co., Ltd. Tetrabutyl titanate Industrial grade Nanjing Tengchuan Technology Co., Ltd. dichloromethane Industrial grade Jiangsu Runfeng Synthetic Technology Co., Ltd. Alkylphenol polyoxyethylene ether Industrial grade Wuhan Xinyang Ruihe Chemical Technology Co., Ltd.

[0130] Example 1:

[0131] The preparation method of the organic sintering aid is as follows: Prepare a mixed solvent by mixing 0.98L of deionized water and 0.42L of anhydrous ethanol at a volume ratio of 7:3. Adjust the pH to 4.5 with 0.1mol / L HCl / NaOH aqueous solution. Take 90% of the mixed solvent, first add 0.12kg of hydroxyethyl cellulose (HEC), and disperse by stirring at 500rpm for 30min in a 40℃ water bath. Then add 0.5kg of acrylic acid-maleic acid copolymer (MA / AA), stir at 500rpm for 15min, and finally add 0.03kg of aluminum citrate and stir for 15min.

[0132] 0.15 kg of 3-aminopropyltriethoxysilane APTES was pre-hydrolyzed alone in 10% solvent at 50 °C for 1 h, and then slowly added dropwise to the main solution at a rate of 1 mL / min.

[0133] The organic sintering aid was obtained by cyclically processing the material three times using a high-pressure homogenizer at 60 MPa and finally filtering it through a 0.45 μm microporous membrane.

[0134] The organic impregnation solution was prepared as follows: 33 L of anhydrous ethanol and 40.5 L of deionized water were added to the reaction vessel and stirred at 120 rpm; 9 kg of methyltriethoxysilane (MTES) and 2.2 kg of γ-glycidoxypropyltrimethoxysilane (GPTMS) were slowly added at a dropping rate of 1 kg / min; the temperature was raised to 50 °C; the pH was adjusted to 4.8 with 0.01 mol / L HCl aqueous solution; and the reaction was maintained at this temperature for 2 h to obtain the pre-hydrolyzed silane solution.

[0135] 0.54 kg of aminated SiO2-TiO2 hybrid sol was mixed with 1.35 kg of carboxylated carbon nanotube dispersion, and then transferred to an ultrasonic bath. The circulating cooling water was turned on, and the ultrasonic parameters were set as follows: amplitude: 60%; probe diameter: Φ20 mm; immersion depth: 1 / 3 of the liquid surface; after ultrasonic treatment, the particle size distribution D90 ≤ 100 nm was detected; the nano-dispersion was obtained by ultrasonic dispersion.

[0136] The pre-hydrolyzed silane solution was cooled to 40°C, and the nano-dispersion was added. 4.5 kg of 4% aluminum acetylacetone ethanol solution was slowly added while stirring at 800 rpm. After the temperature was cooled to 25°C while stirring at 800 rpm, 0.55 kg of polyether siloxane (PES) and 0.88 kg of microencapsulated dodecyltrimethoxysilane were added in sequence.

[0137] Switch to planetary stirring mode and set the rotation speed to 30 rpm for revolution and 60 rpm for rotation; after aging in a nitrogen atmosphere for 48 hours, an organic impregnation solution is obtained.

[0138] S1. Raw material pretreatment: The raw materials kaolin, potassium feldspar and quartz sand are classified using the Neptunus FX series ultrafine hydrocyclone.

[0139] S2. Mixing and granulation: 50 kg of kaolin, 22 kg of potassium feldspar, and 32 kg of quartz sand are loaded into a high-strength nylon mixing tank; organic sintering aids are added to obtain a raw material mixture; the raw material mixture is spray-dried using a centrifugal spray drying tower.

[0140] S3. Molding and pressing: A tungsten carbide hard alloy mold with a hardness of HRA of 95 is used. The surface of the mold cavity is mirror polished to make the roughness Ra of 0.04μm. The mold cavity is cleaned with acetone and sprayed with polytetrafluoroethylene emulsion.

[0141] A spiral feeder at 18 rpm, combined with an ultrasonic vibrating screen at 28 kHz, is used to ensure that the mixed raw materials are evenly filled into the mold cavity.

[0142] The mixed raw materials are pressed using a YT-RS series hot press to obtain a green body;

[0143] The green billet is placed in a constant temperature and humidity chamber at 30℃ and 60%RH, and after standing for 12 hours, it is transferred to a chain drying kiln to obtain the dried billet.

[0144] S4. Sintering: Cordierite pads are used, and an alumina isolation layer with a thickness of 0.1mm is pre-sprayed. The blanks are loaded, and the longitudinal spacing between the blanks is 20mm, and the transverse spacing is 1.2 times the width of the blank.

[0145] The dry blank is sintered to obtain a rough ceramic slab blank;

[0146] S5. Post-processing: The terracotta blank is placed into a pressure-resistant container, and a rotary vane vacuum pump is used to evacuate to a vacuum degree of 0.095MPa. After preheating at 110℃ for 30 minutes to remove surface adsorbed water, the blank is then impregnated to obtain an impregnated blank.

[0147] A tunnel-type curing oven is used to thermally cure the impregnated blank to obtain a thermocured blank.

[0148] A five-axis linkage polishing machine with diamond grinding wheels is used to finely process the surface of the thermosetting blank. After fine grinding, a product with a thickness of 3mm is obtained, namely an ultra-thin dry-hanging ceramic slab.

[0149] The moisture content of the spray-dried mixed raw materials is controlled at 6.2%. The thickness of the dry-pressed fabric is controlled at 2.8 times the forming thickness. The weight gain of the impregnation treatment is controlled at 1.8%.

[0150] Example 2

[0151] The preparation method of the organic sintering aid is as follows: Prepare a mixed solvent by mixing 1.4L of deionized water and 0.6L of anhydrous ethanol at a volume ratio of 7:3. Adjust the pH to 4.7 with 0.1mol / L HCl / NaOH aqueous solution. Take 90% of the mixed solvent, first add 0.15kg of hydroxyethyl cellulose (HEC), stir and disperse at 500rpm for 30min in a 40℃ water bath, then add 0.6kg of acrylic acid-maleic acid copolymer (MA / AA), stir at 500rpm for 15min, then add 0.05kg of aluminum citrate, and stir for 15min.

[0152] 0.2 kg of 3-aminopropyltriethoxysilane APTES was pre-hydrolyzed alone in 10% solvent at 50 °C for 1 h, and then slowly added dropwise to the main solution at a rate of 1 mL / min.

[0153] The organic sintering aid was obtained by cyclically processing the material three times using a high-pressure homogenizer at 60 MPa and finally filtering it through a 0.45 μm microporous membrane.

[0154] The organic impregnation solution is prepared as follows: 30 L of anhydrous ethanol and 45 L of deionized water are added to the reaction vessel and stirred at 120 rpm; 10 kg of methyltriethoxysilane (MTES) and 2 kg of γ-glycidoxypropyltrimethoxysilane (GPTMS) are slowly added at a dropping rate of 1 kg / min; the temperature is raised to 50 °C; the pH is adjusted to 4.8 with 0.01 mol / L HCl aqueous solution; the reaction is maintained at this temperature for 2 h to obtain the pre-hydrolyzed silane solution.

[0155] 0.6 kg of aminated SiO2-TiO2 hybrid sol was mixed with 1.5 kg of carboxylated carbon nanotube dispersion, and then transferred to an ultrasonic bath. The circulating cooling water was turned on, and the ultrasonic parameters were set as follows: amplitude: 60%; probe diameter: Φ20 mm; immersion depth: 1 / 3 of the liquid surface; after ultrasonic treatment, the particle size distribution D90 ≤ 100 nm was detected; the nano-dispersion was obtained by ultrasonic dispersion.

[0156] The pre-hydrolyzed silane solution was cooled to 40°C and the nano-dispersion was added. 5 kg of 4% aluminum acetylacetone ethanol solution was slowly added while stirring at 800 rpm. After the temperature was cooled to 25°C while stirring at 800 rpm, 0.5 kg of polyether siloxane (PES) and 0.8 kg of microencapsulated dodecyltrimethoxysilane were added in sequence.

[0157] Switch to planetary stirring mode and set the rotation speed to 30 rpm for revolution and 60 rpm for rotation; after aging in a nitrogen atmosphere for 48 hours, an organic impregnation solution is obtained.

[0158] S1. Raw material pretreatment: The raw materials kaolin, potassium feldspar, and quartz sand are classified.

[0159] S2. Mixing and granulation: 45 kg of kaolin, 25 kg of potassium feldspar, and 30 kg of quartz sand are loaded into a high-strength nylon mixing tank; organic sintering aids are added to obtain a raw material mixture; the raw material mixture is spray-dried using a centrifugal spray drying tower.

[0160] S3, molding and pressing; S4, sintering; and S5, post-treatment: using steps S3-S5 of Example 1, dry blanks, terracotta panel rough blanks, and ultra-thin dry-hanging terracotta panels are obtained sequentially; the difference is that the thickness of the ultra-thin dry-hanging terracotta panel is 4.5 mm; the moisture content of the mixed raw materials produced by spray drying is controlled at 5.9%; the thickness of the fabric for dry pressing is controlled at 3 times the forming thickness; and the weight gain rate of the impregnation treatment is controlled at 2%.

[0161] Example 3:

[0162] The preparation method of the organic sintering aid is as follows: Prepare a mixed solvent by mixing 1.68L of deionized water and 0.72L of anhydrous ethanol at a volume ratio of 7:3. Adjust the pH to 5.0 with 0.1mol / L HCl / NaOH aqueous solution. Take 90% of the mixed solvent, first add 0.18kg of hydroxyethyl cellulose (HEC), stir and disperse at 500rpm for 30min in a 40℃ water bath, then add 0.7kg of acrylic acid-maleic acid copolymer (MA / AA), stir at 500rpm for 15min, then add 0.07kg of aluminum citrate, and stir for 15min.

[0163] 0.25 kg of 3-aminopropyltriethoxysilane APTES was pre-hydrolyzed alone in 10% solvent at 50 °C for 1 h, and then slowly added dropwise to the main solution at a rate of 1 mL / min.

[0164] The organic sintering aid was obtained by cyclically processing the material three times using a high-pressure homogenizer at 60 MPa and finally filtering it through a 0.45 μm microporous membrane.

[0165] The organic impregnation solution was prepared as follows: 27 L of anhydrous ethanol and 49.5 L of deionized water were added to the reaction vessel and stirred at 120 rpm; 11 kg of methyltriethoxysilane (MTES) and 1.8 kg of γ-glycidoxypropyltrimethoxysilane (GPTMS) were slowly added at a dropping rate of 1 kg / min; the temperature was raised to 50 °C; the pH was adjusted to 4.9 with 0.01 mol / L HCl aqueous solution; and the reaction was maintained at this temperature for 2 h to obtain the pre-hydrolyzed silane solution.

[0166] 0.66 kg of aminated SiO2-TiO2 hybrid sol was mixed with 1.65 kg of carboxylated carbon nanotube dispersion, and then transferred to an ultrasonic bath. The circulating cooling water was turned on, and the ultrasonic parameters were set as follows: amplitude: 60%; probe diameter: Φ20 mm; immersion depth: 1 / 3 of the liquid surface; after ultrasonic treatment, the particle size distribution D90 ≤ 100 nm was detected; and the nano-dispersion was obtained by ultrasonic dispersion.

[0167] The pre-hydrolyzed silane solution was cooled to 40°C, and the nano-dispersion was added. 4.5 kg of 4% aluminum acetylacetone ethanol solution was slowly added while stirring at 800 rpm. After the temperature was cooled to 25°C while stirring at 800 rpm, 0.45 kg of polyether siloxane (PES) and 0.72 kg of microencapsulated dodecyltrimethoxysilane were added in sequence.

[0168] Switch to planetary stirring mode and set the rotation speed to 30 rpm for revolution and 60 rpm for rotation; after aging in a nitrogen atmosphere for 48 hours, an organic impregnation solution is obtained.

[0169] S1. Raw material pretreatment: The raw materials kaolin, potassium feldspar, and quartz sand are classified.

[0170] S2. Mixing and granulation: 40 kg of kaolin, 28 kg of potassium feldspar, and 28 kg of quartz sand are loaded into a high-strength nylon mixing tank; organic sintering aids are added to obtain a raw material mixture; the raw material mixture is spray-dried using a centrifugal spray drying tower.

[0171] S3, molding and pressing; S4, sintering; and S5, post-treatment: using steps S3-S5 of Example 1, dry blanks, terracotta panel blanks, and ultra-thin dry-hanging terracotta panels are obtained sequentially; the difference is that the thickness of the ultra-thin dry-hanging terracotta panel is 6 mm; the moisture content of the mixed raw materials produced by spray drying is controlled at 5.6%; the thickness of the fabric for dry pressing is controlled at 3.2 times the forming thickness; and the weight gain rate of the impregnation treatment is controlled at 2.2%.

[0172] Comparative Examples 1-36 were also designed based on this, and their specific formulations are shown in Tables 2, 3, and 4:

[0173] Table 2. Dry blank formula for ultra-thin dry-hanging terracotta panels

[0174]

[0175] Table 3. Organic Impregnation Solution Formula for Ultra-thin Dry-hanging Ceramic Panels

[0176]

[0177] Table 4. Production process of ultra-thin dry-hanging terracotta panels

[0178]

[0179] According to GB / T 39156-2020 "Technical Requirements and Test Methods for Large-Size Ceramic Plates", the performance of the ceramic plates was tested, as shown in Table 5:

[0180] Table 5. Performance test data of dry-hanging terracotta panels

[0181]

[0182] Of the 36 comparative examples, examples 2, 4, 6, 16, 18, 30, 32, and 36 failed to form ceramic slabs. Data analysis shows that:

[0183] By comparing Examples 1, 2, and 3, as well as Comparative Examples 1 and 2, it can be seen that kaolin is one of the main raw materials for ceramics. Without kaolin, ceramic sintering will fail. Kaolin dehydration to form mullite requires high temperature. When there is too much kaolin, local shrinkage is uneven and porosity increases. Excessive kaolin will lead to a decrease in the sintering performance of the product, a decrease in mechanical strength, and an increase in water absorption.

[0184] By comparing Examples 1, 2, and 3, as well as Comparative Examples 3 and 4, it can be seen that the absence of potassium feldspar will lead to ceramic sintering failure. As a flux, excessive potassium feldspar will excessively reduce viscosity, destroy the particle skeleton, and also lower the sintering temperature, resulting in deformation, reduced strength, and poorer weather resistance of the ceramic slab.

[0185] By comparing Examples 1, 2, and 3, as well as Comparative Examples 5 and 6, it can be seen that not adding quartz stone will lead to ceramic sintering failure. Excessive quartz sand will result in insufficient reaction with the melt at high temperature, and the residual particles will become stress concentration points, thereby increasing the brittleness of the product, leading to sintering difficulties and surface roughness.

[0186] By comparing Examples 1, 2, and 3, and Comparative Examples 7 and 8, it can be seen that an excessive amount of acrylic acid-maleic acid copolymer will result in an overly thick binder coating, difficulty in venting during pressing, uneven green density, and consequently low green strength, sintering residue, and cost waste. Conversely, an insufficient amount will significantly reduce particle dispersibility, leading to uneven mixing of raw materials, resulting in decreased density during sintering, reduced flexural strength, and increased surface roughness.

[0187] By comparing Examples 1, 2, 3, 9, and 10, it can be seen that an excess of γ-aminopropyltriethoxysilane will lead to the formation of large molecular clusters due to self-condensation and deterioration of dispersibility, resulting in surface hydrophobicity, uneven curing, and a sharp increase in cost. Insufficient γ-aminopropyltriethoxysilane will reduce the interfacial bonding energy, exacerbate the stress concentration phenomenon inside the sintered body, and damage the product performance.

[0188] By comparing Examples 1, 2, and 3, as well as Comparative Examples 11 and 12, it can be seen that excessive hydroxyethyl cellulose results in excessively high viscosity of the mixture, uneven atomization, and difficulty in spray drying. At the same time, high viscosity hinders solvent evaporation, leading to more carbonized cellulose residue during sintering, as well as sticking to the mold, making demolding difficult and reducing surface smoothness. Insufficient hydroxyethyl cellulose, on the other hand, leads to slurry sedimentation, increased unevenness in sintering shrinkage, resulting in warping deformation and large thickness deviation.

[0189] By comparing Examples 1, 2, and 3, as well as Comparative Examples 13 and 14, it can be seen that excessive aluminum citrate leads to the enrichment of aluminum ions, local over-sintering, warping deformation, and decreased flatness. At the same time, excessive cross-linking of aluminum ions with the silicon-oxygen network and the dense surface layer prevent the penetration of organic impregnation liquid, resulting in a decrease in the product's antioxidant capacity. When the amount is insufficient, the amount of mullite generated decreases and the elastic modulus decreases.

[0190] Comparative examples 1, 2, 3, and Comparative Examples 15 and 16 show that the main function of the aminated SiO2-TiO2 hybrid sol is to improve the mechanical strength, wear resistance, and weather resistance of the ceramic slab. Its amino functional groups can chemically react with the ceramic slab matrix to form chemical bonds, thereby enhancing the bonding force. SiO2 provides hardness and strength, while TiO2 provides UV shielding and photocatalytic properties, resisting UV aging. Excessive amounts will result in excessively high viscosity of the impregnation solution, making it difficult to penetrate the pores of the ceramic slab, and also leading to large shrinkage after curing, causing surface cracking. Conversely, insufficient amounts will lead to decreased mechanical properties, brittleness, inadequate pore filling, increased water absorption, and weakened weather resistance.

[0191] Comparative studies of Examples 1, 2, 3, and Comparative Examples 17 and 18 show that the function of microencapsulated dodecyltrimethoxysilane (DTMS) is to release DTMS during the thermosetting stage, forming a hydrophobic surface, reducing the water absorption rate of the ceramic panel, preventing water droplets and oil stains from adhering, and improving stain resistance. Excessive amounts result in an overly thick hydrophobic layer, reducing its adhesion to the substrate and making it prone to peeling during polishing. It may also cause uncontrolled release, leading to concentrated release during the thermosetting stage and forming surface oil spots or uneven hydrophobicity. Conversely, insufficient amounts lead to increased water absorption, making the ceramic panel more susceptible to moisture absorption and reducing stain resistance.

[0192] Comparative studies of Examples 1, 2, 3, and Comparative Examples 19 and 20 show that methyltriethoxysilane (MTES) primarily functions to form a silicon-oxygen network, enhancing the density and strength of the terracotta panel. Excessive amounts can lead to over-polymerization, premature gelation of the impregnation solution, and blockage of the vacuum impregnation equipment. Furthermore, an overly dense silicon-oxygen network reduces the impact resistance of the terracotta panel, making it prone to edge chipping during dry-hanging installation. Insufficient amounts result in the terracotta panel's internal pores not being effectively filled, significantly reducing its strength and corrosion resistance, and causing insufficient impregnation solution penetration, leading to a weight gain rate below the standard range.

[0193] Comparative studies of Examples 1, 2, 3, and Comparative Examples 21 and 22 show that glycidyl etheroxypropyltrimethoxysilane (GPTMS) provides epoxy groups, enhancing the interfacial bonding between the impregnation liquid and the ceramic substrate, and improving the chemical resistance of the ceramic panel. Excessive amounts lead to over-crosslinking, increased internal stress during curing, and decreased flexural strength of the ceramic panel. Furthermore, excessive epoxy groups can adsorb environmental dust, affecting aesthetics. Conversely, a deficiency weakens the interfacial bonding, reduces the adhesion between the ceramic panel and the impregnation layer, making it prone to delamination or peeling, and reduces acid and alkali resistance, making the ceramic panel susceptible to corrosion in acidic and alkaline environments.

[0194] Comparative studies of Examples 1, 2, 3, 23, and 24 show that aluminum acetylacetonate is a catalyst. Its main function is to catalyze the hydrolysis and condensation reaction of silanes, regulate the curing rate, prevent cracking, and improve the uniformity of crosslinking density distribution within the ceramic panel. Excessive amounts can lead to overly rapid catalysis, causing the impregnation solution to gel in the storage tank, shortening the shelf life. Simultaneously, it can cause excessively rapid surface hardening during heat curing, hindering the evaporation of internal solvents and resulting in blistering. Conversely, insufficient amounts can lead to uneven curing, uncontrolled reaction rates, potentially resulting in localized excessive shrinkage or cracking, fluctuations in mechanical properties, and inconsistent strength distribution within the ceramic panel.

[0195] Comparing Examples 1, 2, and 3, as well as Comparative Examples 25 and 26, it is evident that the main function of polyether siloxane (PES) is to improve the leveling of the impregnation solution and the smoothness of the ceramic tile surface. Excessive use will make the surface too slippery, causing the diamond grinding wheel to slip during polishing and reducing finishing efficiency. Conversely, insufficient use will lead to surface defects, such as orange peel and pinholes, affecting the decorative effect. Simultaneously, it will reduce processing performance, increase resistance during polishing, and decrease finishing efficiency.

[0196] Comparative studies of Examples 1, 2, 3, 27, and 28 show that the main function of the carboxylated carbon nanotube dispersion is to improve the impact resistance and thermal conductivity of the terracotta panel, alleviate thermal stress, and enhance thermal stability. Excessive amounts can lead to dispersion difficulties, making it hard to achieve the desired dispersion degree through ultrasonic treatment, resulting in agglomerates that become stress concentration points. Simultaneously, increased conductivity may interfere with building lightning protection systems. Conversely, insufficient amounts can lead to reduced toughness, increased brittleness of the terracotta panel, easy edge chipping during dry-hanging installation, decreased thermal stability, and increased risk of thermal deformation.

[0197] By comparing Examples 1, 2, and 3, as well as Comparative Examples 29 and 30, it can be seen that the moisture content of spray drying affects the particle flowability of the raw material mixture. When the moisture content is >6.5%, the particles stick together, and when it is <5.0%, the dust increases. Both of these will increase the unevenness of sintering shrinkage, thereby affecting the strength of the green body.

[0198] By comparing Examples 1, 2, and 3, as well as Comparative Examples 31 and 32, it can be seen that the thickness of the fabric affects the pressure transmission gradient and density uniformity during dry pressing. When the fabric is too thin, the strength of the blank is insufficient, making it difficult to form. When the fabric is too thick, there is not only a risk of delamination, but also a decrease in dimensional accuracy.

[0199] By comparing Examples 1, 2, and 3, as well as Comparative Examples 33 and 34, it can be seen that the weight gain rate of vacuum impregnation affects the surface quality of the product, especially the degree of color difference under ultraviolet aging, and deviations from the standard lead to differences in gloss.

[0200] By comparing Examples 1, 2, and 3, as well as Comparative Examples 35 and 36, it can be seen that although producing thinner and stronger terracotta panels is an inevitable trend, terracotta panels are still ceramic materials after all. With the current level of technology, it is still difficult to mass-produce 1mm terracotta panels.

[0201] In summary, Embodiment 2 of the present invention exhibits optimal performance. In terms of raw material usage, the proportions of each raw material are reasonable; in terms of process, the key parameters are well set, and the produced ultra-thin dry-hanging terracotta panels demonstrate excellent performance in all aspects, making it the preferred choice for producing terracotta panel products.

Claims

1. An ultra-thin dry-hanging terracotta panel, characterized in that, The raw materials include the following parts by weight: 40-50 parts kaolin; 22-28 parts potassium feldspar; 28-32 parts quartz sand; organic sintering aid; organic impregnation solution; The organic sintering aids specifically include: 0.5-0.7 parts of acrylic acid-maleic acid copolymer; 0.15-0.25 parts of 3-aminopropyltriethoxysilane; 0.12-0.18 parts of hydroxyethyl cellulose; 0.03-0.07 parts of aluminum citrate; and 0.42-0.72 parts of anhydrous ethanol. 0.98-1.68 parts of deionized water; The organic impregnation solution specifically includes: 0.54-0.66 parts of aminated SiO2-TiO2 hybrid sol; 0.72-0.88 parts of microencapsulated dodecyltrimethoxysilane; 9-11 parts of methyltriethoxysilane; 1.8-2.2 parts of γ-glycidyl etheroxypropyltrimethoxysilane; 0.18-0.22 parts of aluminum acetylacetonate; 0.45-0.55 parts of polyether siloxane; 1.35-1.65 parts of a 1% (w / w) carboxylated carbon nanotube dispersion; 31.5-38.5 parts of anhydrous ethanol; and 40.5-49.5 parts of deionized water.

2. The ultra-thin dry-hanging terracotta panel according to claim 1, characterized in that: The preparation method of the organic sintering aid is as follows: Prepare a mixed solvent by mixing deionized water and anhydrous ethanol at a volume ratio of 7:

3. Adjust the pH to 4.5-5.0 with 0.1 mol / L HCl / NaOH aqueous solution. Take 90% of the mixed solvent, first add hydroxyethyl cellulose (HEC), and disperse by stirring at 500 rpm for 30 min in a 40°C water bath. Then add acrylic acid-maleic acid copolymer (MA / AA), and stir at 500 rpm for 15 min. Finally, add aluminum citrate and stir for 15 min to obtain the main solution. 3-Aminopropyltriethoxysilane APTES was pre-hydrolyzed alone in 10% solvent at 50°C for 1 h, and then slowly added dropwise to the main solution at a rate of 1 mL / min. The organic sintering aid was obtained by cyclically processing the material three times using a high-pressure homogenizer at 60 MPa and finally filtering it through a 0.45 μm microporous membrane.

3. The ultra-thin dry-hanging terracotta panel according to claim 1, characterized in that: The organic impregnation solution is prepared as follows: ① Preparation of aminated SiO2-TiO2 hybrid sol TEOS was mixed with anhydrous ethanol at a volume ratio of 1:20 and stirred at 25°C for 10 minutes. HNO3 was slowly added dropwise to adjust the pH to 2. The mixture was stirred at 500 rpm for 2 hours in a 40°C water bath to form a transparent SiO2 sol. Tetrabutyl titanate (TBOT) was mixed with anhydrous ethanol at a volume ratio of 1:10 to obtain a TBOT solution, which was then kept in an ice bath at 4°C for later use. The SiO2 sol was heated to 60°C, and a TBOT solution was slowly added, wherein the molar ratio of TEOS to TBOT was 3:1; the mixture was stirred at 100 rpm for 3 hours, and the pH was maintained at 2 ± 0.

5. Add 3-aminopropyltriethoxysilane APTES, wherein the molar ratio of TEOS to APTES is 1:5; continue the reaction for 1 hour to introduce amino functional groups and obtain an aminated SiO2-TiO2 hybrid sol solution; allow the aminated SiO2-TiO2 hybrid sol solution to stand at room temperature for 12 hours to allow the polycondensation reaction to be complete. The sol was placed in a dialysis bag and dialyzed in deionized water for 48 hours; then centrifuged at 5000 rpm for 10 minutes and the supernatant was collected, which is the aminated SiO2-TiO2 hybrid sol. ② Preparation of microencapsulated dodecyltrimethoxysilane Microencapsulated dodecyltrimethoxysilane was prepared using the sol-gel method at a constant temperature of 40°C. Dodecyltrimethoxysilane was added to a mixed solution of dichloromethane and deionized water and stirred at 300 rpm until homogeneous. Alkylphenol polyoxyethylene ether OP-10 and ammonia were added sequentially, followed by the slow addition of TEOS dropwise. After reacting for 1 hour, MTES was added dropwise, and the reaction was continued for 4 hours. The mixture was then cooled to room temperature, washed with water and ethanol, and dried at 85°C to obtain a white powder, i.e., microencapsulated dodecyltrimethoxysilane. The mass ratio of dodecyltrimethoxysilane, OP-10, DTMS, TEOS, dichloromethane, and deionized water was 5:0.01:0.4:1:20:

50. ③Prepare the impregnation solution Anhydrous ethanol and deionized water were added to the reaction vessel and stirred at 120 rpm. Methyltriethoxysilane (MTES) and γ-glycidoxypropyltrimethoxysilane (GPTMS) were slowly added at a dropping rate of 1 kg / min. The temperature was raised to 50 °C, and the pH was adjusted to 4.8 ± 0.2 with 0.01 mol / L HCl aqueous solution. The reaction was maintained at this temperature for 2 h to obtain a pre-hydrolyzed silane solution. The mass ratio of anhydrous ethanol, deionized water, MTES, and GPTMS was 27-33:40.5-49.5:9-11:1.8-2.

2. Aminated SiO2-TiO2 hybrid sol and carboxylated carbon nanotube dispersion were mixed and transferred into an ultrasonic bath. Circulating cooling water was turned on, and the ultrasonic parameters were set as follows: amplitude: 60%; probe diameter: Φ20mm; immersion depth: 1 / 3 of the liquid surface. After ultrasonic treatment, the particle size distribution D90 ≤ 100nm was detected. Nanoparticle dispersion was obtained through ultrasonic dispersion. The mass ratio of aminated SiO2-TiO2 hybrid sol to carboxylated carbon nanotube dispersion was 0.54-0.66:1.35-1.

65. Cool the pre-hydrolyzed silane solution to 40°C and add the nano-dispersion; slowly add a 4% (w / w) aluminum acetylacetonate ethanol solution while stirring at 800 rpm; the mass ratio of the pre-hydrolyzed silane solution, nano-dispersion and aluminum acetylacetonate ethanol solution is 78.3-95.7:1.8-2.2:0.68-5.

72. After stirring at 800 rpm and cooling to 25°C, polyether siloxane (PES) and microencapsulated dodecyltrimethoxysilane (DTS) are added sequentially; the mass ratio of PES to DTS is 0.45-0.55: 0.72-0.

88. Switch to planetary stirring mode and set the rotation speed to 30 rpm for revolution and 60 rpm for rotation; after aging in a nitrogen atmosphere for 48 hours, an organic impregnation solution is obtained.

4. The ultra-thin dry-hanging terracotta panel according to claim 1, characterized in that: The thickness of the ceramic slab is 3-6 mm.

5. A method for preparing an ultra-thin dry-hanging ceramic slab according to any one of claims 1-4, characterized in that: Includes the following steps: S1. Raw material pretreatment The Neptune FX series ultra-fine classifying hydrocyclones are used to classify raw materials such as kaolin, potassium feldspar, and quartz sand. S2, Mixed Granulation Kaolin, potassium feldspar, and quartz sand are loaded into a high-strength nylon mixing tank; Organic sintering aids were added to the mixing tank using an atomizing spray device with a nozzle diameter of 0.3 mm, a spray pressure of 0.4 MPa, and a spray angle of 45°. The three-dimensional motion of the mixing tank was set to 10 rpm revolution and 25 rpm rotation, with a motion time of 30 min, to obtain the raw material mixture. The raw material mixture is spray-dried using a centrifugal spray drying tower. Specific parameter settings are as follows: The feed pump pressure is 1.2 MPa; Inlet temperature is controlled in stages: 320℃ at the top of the tower, 280℃ in the middle of the tower, and 110℃ at the bottom of the tower. The negative pressure of the cyclone separator is maintained at 1500Pa. After the product passes through a 40-mesh sieve, a mixed raw material is obtained. The moisture content of the mixed raw material is determined by an infrared rapid moisture analyzer and collected for later use. S3, Molding and Pressing A tungsten carbide hard alloy mold with a hardness of HRA≥90 is used. The surface of the mold cavity is mirror polished to make the roughness Ra≤0.05μm. The mold cavity is cleaned with acetone and then sprayed with polytetrafluoroethylene emulsion. A spiral feeder at 18 rpm, combined with an ultrasonic vibrating screen at 28 kHz, is used to ensure that the mixed raw materials are evenly filled into the mold cavity. The mixed raw materials are pressed using a YT-RS series hot press to obtain a green body; Press parameters for pressing mixed raw materials: Pre-compression stage: The pressure is increased from 0 to 5MPa at a pressurization rate of 5MPa / s, the pressure is vented once, and the pressure is maintained for 1.5s; During the main pressure stage, the pressure is increased from 5MPa to 35MPa at a pressurization rate of 3MPa / s, and held for 8s. At pressures of 20MPa and 35MPa, the pressure is vented once each. Decompression phase: The pressure was reduced from 35 MPa to 20 MPa at a rate of 15 MPa / s; The pressure was reduced from 20 MPa to 8 MPa at a rate of 12 MPa / s; The pressure was reduced from 8 MPa to complete depressurization at a rate of 8 MPa / s; The green billets were placed in a constant temperature and humidity chamber at 30±2℃ and 60±5%RH, and after standing for 12 hours, they were transferred to a chain drying kiln. The chain drying kiln was controlled in three zones: Zone 1: Temperature set at 80℃, humidity controlled at 40%RH, wind speed at 1.5m / s, for 20 minutes; Zone 2: Temperature set at 105℃, humidity controlled at 25%RH, wind speed at 3m / s, for 40 minutes; Zone 3: Temperature set at 60℃, natural humidity, wind speed at 4.5m / s, for 10 minutes; Drying is complete to obtain a dry blank; S4, sintering Cordierite pads are used, and an aluminum oxide isolation layer with a thickness of 0.1mm is pre-sprayed. The blanks are loaded with blanks, and the longitudinal spacing between the blanks is 20mm, and the transverse spacing is 1.2 times the width of the blank. The dry blank is sintered at the following temperature: The heating rate is 2℃ / min, from room temperature to 200℃; Heating rate 1℃ / min, from 200℃ to 500℃ The heating rate is 5℃ / min, from 500℃ to 900℃; The heating rate is 2℃ / min, from 900℃ to 1120℃; Keep warm at 1120℃ for 30 minutes; The cooling rate is 20℃ / min, and the temperature drops to 700℃. The temperature was reduced to room temperature at a rate of 5℃ / min to obtain a rough ceramic slab blank. S5, Post-processing S5.1 Vacuum impregnation: The terracotta blanks were placed into a pressure-resistant container, and a rotary vane vacuum pump was used to evacuate the container to a vacuum level of 0.095 MPa. The container was preheated at 110°C for 30 minutes to remove surface adsorbed water, and then impregnated to obtain impregnated blanks. The program was set as follows: Evacuate to -0.095 MPa and hold for 15 minutes; Inject the organic impregnation solution, pressurize to 0.4 MPa, maintain the pressure for 25 minutes, and then drain the solution; After draining, centrifuge at 800 rpm for 2 minutes to remove the liquid; Record the mass of the terracotta slab blank and the impregnated blank, and calculate the weight gain rate. S5.2, Thermosetting: A tunnel curing oven is used to heat-cure the impregnated blanks. The program is set as follows: The heating rate was 5℃ / min, the temperature was increased from room temperature to 180℃, the holding time was 40min, and the atmosphere was air. The heating rate was 2℃ / min, from 180℃ to 300℃, and the holding time was 90min. The atmosphere was nitrogen. The cooling rate is 3℃ / min, reducing the temperature from 300℃ to room temperature through forced air convection; After thermosetting, a thermoset blank is obtained; S5.3 Surface Finishing A five-axis linkage polishing machine with diamond grinding wheels is used for finishing the surface of a thermosetting blank. The program is set as follows: Rough grinding stage: Use a 150# grinding wheel at a speed of 2500 rpm and a feed rate of 1.2 m / min for rough grinding. This stage is cooled by water. Semi-finish grinding stage: Use a 400# grinding wheel at a speed of 3500 rpm and a feed rate of 0.8 m / min for semi-finish grinding. This stage is cooled by mist cooling. Fine polishing stage: Use a 3000# grinding wheel at a speed of 5000 rpm and a feed rate of 0.3 m / min for fine polishing. This stage is dry polishing without cooling. After fine grinding, the product is obtained: ultra-thin dry-hanging terracotta panels.

6. The method for preparing an ultra-thin dry-hanging ceramic slab according to claim 5, characterized in that: In step S1, the kaolin is graded by controlling the particle size distribution of kaolin (D90 < 10 μm, 4 μm < D50 < 6 μm), removing iron impurities, and ensuring the Fe2O3 content is < 0.5%; the potassium feldspar is graded by controlling the particle size distribution of potassium feldspar (D90 < 15 μm, 5 μm < D50 < 8 μm); and the quartz sand is graded by controlling the particle size distribution of quartz sand (D90 < 25 μm, 10 μm < D50 < 15 μm). After grading, the kaolin, potassium feldspar, and quartz sand are dried in an oven at 105℃ until the moisture content is < 1%.

7. The method for preparing an ultra-thin dry-hanging ceramic slab according to claim 5, characterized in that: In step S2.2, the moisture content of the mixed raw materials produced by spray drying is controlled at 5.5%-6.2%.

8. The method for preparing an ultra-thin dry-hanging ceramic slab according to claim 5, characterized in that: In step S3.2, the thickness of the fabric formed by dry pressing is controlled to be 2.8-3.2 times the forming thickness.

9. The method for preparing an ultra-thin dry-hanging ceramic slab according to claim 5, characterized in that: In step S5.1, the weight gain rate of the impregnation treatment is controlled between 1.8% and 2.2%.

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