A colored dry granule and its preparation method

Abstract

This invention discloses a colored dry granule and its preparation method, relating to the field of ceramic materials technology. The colored dry granule is composed of a frit base material and a slow-release colorant; its stability under high-temperature conditions is effectively ensured through a double-layer coating of alumina and silica and hydrophobic modification; the alumina / silica shell has good compatibility with the frit base material (silicate-based), and Al... 3+ It can be integrated into the silicate network. The ODS layer adjusts the interfacial tension through hydrophobicity, reducing agglomeration and making the colorant and the base material more tightly bonded. The porous slow-release structure can realize the controllable release of color ions, avoiding the decomposition of colorants or reaction aging caused by high temperature. Hydrophobic modification reduces the agglomeration of colorants, making them more uniformly dispersed in the molten block, avoiding the color spots or batch differences of traditional dry granules. The slow-release mechanism ensures that color ions are released gradually, avoiding crystallization or color shift caused by local oversaturation.

Description

Technical Field

[0001] This invention relates to the field of ceramic materials technology, and in particular to a colored dry granule and its preparation method. Background Technology

[0002] With people's pursuit of quality of life and spatial aesthetics, ceramic tiles, as a mainstay of home decoration, have developed into a rich variety of colors and textures. The problems with traditional glazed ceramic tiles on the market are insufficient glaze smoothness and poor transparency, resulting in unclear designs and an inability to perfectly showcase the textures and details of the designs. Clearly, they no longer meet the market's demands for interior decoration, making product upgrades imperative. Currently, in the ceramic tile industry, many domestic and international companies have launched dry-granule glaze products, such as dry-granule polished tiles, modern antique tiles, and landscape tiles. Compared to glazed ceramic tiles, dry-granule polished tiles have advantages such as strong glaze transparency, good layering of patterns, vibrant colors, and high mirror finish. Modern antique-style tiles utilize a large amount of frit dry granules, resulting in different textures, tactile sensations, and glosses on their surfaces. They can be finished without polishing, semi-polished, or matte-polished, making the product range extremely diverse. Modern antique-style tiles have become a key development direction for major ceramic tile companies. Dry granule glazes have also boosted the development of landscape tiles, garden tiles, and paving stones that imitate granite.

[0003] Colored dry granules, as an important ceramic decorative material, can endow ceramic tiles with unique colors and textures. However, existing colored dry granules have many problems in practical applications. Many colored dry granule products on the market are made from ceramic raw materials used in glazes (such as potassium feldspar, quartz, alumina, calcite, dolomite, calcined talc, barium carbonate, zinc oxide, etc.), colored with inorganic pigments, ball-milled, sprayed with powder, and then heat-treated at a low temperature (approximately 1000℃). Because these colored dry granules have not undergone high-temperature melting, they have significant defects in use. For example, they are easily broken into a slurry when directly mixed with water and suspending agents, seriously affecting their use; their low specific gravity makes them prone to segregation when mixed with other materials, resulting in uneven decorative effects; the particle size is not adjustable, making it difficult to meet diverse design needs; the colors are not bright and glossy enough, and the texture is not transparent enough, failing to bring high-quality decorative effects to ceramic tiles. Furthermore, most pigments lose color at high temperatures, which also limits the application of colored dry granules in some ceramic tile production processes that require high-temperature stability. Summary of the Invention

[0004] One of the objectives of this invention is to provide a colored dry granule to solve the problem of insufficient color vibrancy and gloss.

[0005] The second objective of this invention is to provide a method for preparing colored dry granules.

[0006] The objective of this invention can be achieved through the following technical solutions:

[0007] In a first aspect, a colored dry granule is composed of a frit base material and a slow-release colorant; wherein the slow-release colorant is prepared by the following steps:

[0008] S1. Add the colorant powder to anhydrous ethanol, disperse it by ultrasonication to obtain a uniform suspension, slowly add ethyl silicate (TEOS) / ethanol solution (a mixed solution of ethyl silicate and ethanol), while adjusting the pH to 9-10 with ammonia water, stir the reaction at room temperature (25-30℃) for 5-8 hours, let it stand for 10-20 hours, collect by centrifugation, dry it, grind it and sieve it to obtain the intermediate;

[0009] S2. Disperse the intermediate in a solvent, add aluminum nitrate (Al(NO3)3·9H2O), ultrasonically disperse for 30-60 min, add urea solution dropwise at 60-65℃, control the pH to 8-9, let the reaction stand for 6-10 h, collect by centrifugation, and calcine to obtain the slow-release colorant semi-finished product.

[0010] S3. Under nitrogen protection, the semi-finished slow-release colorant is added to toluene, and octadecyltrimethoxysilane (ODS) and glacial acetic acid are added dropwise. The mixture is stirred and refluxed at 75-85℃ for 8-12 hours. After centrifugation, washing, vacuum drying, and annealing, the slow-release colorant is obtained.

[0011] Furthermore, the weight ratio of the frit base material to the slow-release colorant is 100:0.5-8.

[0012] Furthermore, the colorant is one or a combination of cobalt oxide, copper oxide, iron oxide, cerium oxide, zirconium oxide, titanium oxide, praseodymium oxide, manganese oxide, cobalt oxide, nickel oxide, and chromium oxide.

[0013] Furthermore, in S1, the weight ratio of the colorant to ethyl silicate is 100:25-35.

[0014] Furthermore, in S1, the solid content of the suspension is 30%-50%.

[0015] Furthermore, in S1, the ratio of ethyl silicate to ethanol in the ethyl silicate / ethanol solution is 1g:1mL.

[0016] Furthermore, in S1, the dropping rate of the ethyl silicate / ethanol solution is 1-1.5 mL / min.

[0017] Furthermore, the stirring speed is 400-500 rpm.

[0018] Furthermore, in S1, the drying temperature is 70-90℃; the grinding sieve mesh size is 400 mesh.

[0019] Furthermore, in S2, the solvent is a mixture of water and ethanol in a 1:1 volume ratio.

[0020] Furthermore, the (Si / Al) molar ratio of ethyl silicate to aluminum nitrate is 2-4:1.

[0021] Furthermore, in S2, the mass fraction of the urea solution is 30%-40%.

[0022] Furthermore, in S2, the calcination temperature is 500℃ and the calcination time is 1-3h.

[0023] Furthermore, in S3, the ratio of the slow-release colorant semi-finished product, octadecyltrimethoxysilane, toluene, and glacial acetic acid is 1g:0.2-0.4mL:50mL:0.04-0.1mL.

[0024] Furthermore, in S3, the vacuum drying temperature is 60°C and the drying time is 10-20h; the annealing temperature is 140-180°C and the annealing time is 1-3h, thereby enhancing the ordered arrangement of the C18 chains through annealing.

[0025] Furthermore, the frit base material comprises the following components by mass fraction: SrO: 0-8%; Al2O3: 12-15%; CaO: 7-10%; MgO: 1-4%; K2O: 3.5-5.5%; Na2O: 2-4.5%; BaO: 0.5-8.5%; ZnO: 4-10%; SiO2: balance.

[0026] Secondly, a method for preparing colored dry granules includes the following steps:

[0027] The frit base material is melted at 1450-1550℃ to obtain a homogeneous liquid phase, which is then quenched in water, dried to remove moisture, and pulverized to 40-80 mesh. A slow-release colorant is then added, melted at 1400-1500℃, quenched in water, dried, and sieved to obtain colored dry granules.

[0028] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0029] 1. This invention provides a colored dry granule composed of a frit base material and a slow-release colorant. Through a double-layer coating of alumina and silica and hydrophobic modification, its stability under high-temperature conditions is effectively ensured. The alumina / silica shell has good compatibility with the frit base material (silicate-based). 3+It can be integrated into the silicate network. The ODS layer adjusts the interfacial tension through hydrophobicity, reduces agglomeration, and makes the colorant and the base material more tightly bonded. The porous slow-release structure can realize the controllable release of color ions, avoiding colorant decomposition or reaction aging caused by high temperature. Hydrophobic modification (ODS) reduces colorant agglomeration, making it more uniformly dispersed in the molten block, avoiding the color spots or batch differences problems of traditional dry granules. The slow-release mechanism ensures that color ions are released gradually, avoiding crystallization or color shift caused by local oversaturation.

[0030] 2. This invention utilizes a sol-gel method, where ethyl silicate hydrolyzes under alkaline conditions to generate SiO2, which uniformly coats the surface of colorant particles, forming a porous silicon shell. This layer structure delays the decomposition of the colorant during high-temperature melting and avoids direct reaction with the frit base material. Urea hydrolysis provides OH-. - It reacts with aluminum nitrate to form Al(OH)3, which, upon calcination, transforms into an Al2O3 coating layer. The high melting point (2050℃) and chemical inertness of Al2O3 further protect the colorant, preventing it from reacting with the molten metal at high temperatures. Octadecyltrimethoxysilane (ODS) bonds to the particle surface via silanol groups, forming a hydrophobic long-chain layer. This treatment reduces colorant agglomeration during melting, improves dispersibility, and simultaneously lowers the interfacial energy with the molten metal at high temperatures.

[0031] 3. In the preparation of colored base material, this invention uses stepwise melting and composite dispersion. The molten base material is first melted at a high temperature of 1450-1550℃ to form a uniform liquid phase, and then rapidly cooled with water to obtain glassy particles (to avoid component segregation). After pulverization, it provides a suitable particle size (40-80 mesh) for subsequent mixing with colorants. After adding the slow-release colorant, it is melted a second time at 1400-1500℃ (the temperature is lower than the first time to avoid excessive decomposition of the colorant). At this time, the multi-layer shell of the slow-release colorant gradually "releases" the colorant (the ODS layer decomposes slowly at high temperature, and the alumina / silica shell layer controls the diffusion rate of the colorant), so that the colorant is uniformly dispersed in the molten base material. The multi-layer inorganic shell (silica / alumina, melting points of about 1723℃ and 2054℃ respectively) can withstand the secondary melting temperature of 1400-1500℃, effectively blocking the damage of the core colorant by high temperature. It can also resist acid and alkali corrosion and water vapor corrosion during long-term use, and the color is not easy to fade. Detailed Implementation

[0032] The specific embodiments of the present invention will be described in detail below, but it should be understood that the scope of protection of the present invention is not limited to the specific embodiments.

[0033] The terminology used in the embodiments of this application is for the purpose of describing particular implementations only and is not intended to be limiting of this application. The singular forms “a,” “the,” and “the” used in the implementations of this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

[0034] It should be understood that in the various embodiments of this application, the sequence number of each process does not imply the order of execution. Some or all steps may be executed in parallel or sequentially. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the implementation regulations of this application.

[0035] The weights of the relevant components mentioned in the embodiments of this application can refer not only to the specific content of each component, but also to the proportional relationship between the weights of the components. Therefore, any scaling up or down of the content of the relevant components according to the embodiments of this application is within the scope disclosed in the embodiments of this application. Specifically, the mass described in the embodiments of this application can be a mass unit known in the chemical industry, such as μg, mg, g, or kg.

[0036] Unless otherwise defined, all technical terms used herein have the same meaning as commonly understood by those skilled in the art. The technical terms used herein are for the purpose of describing particular embodiments only and are not intended to limit the scope of the invention.

[0037] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this application are available on the market or can be prepared by existing methods.

[0038] The following description, in conjunction with specific embodiments, provides further details.

[0039] Preparation Example 1

[0040] A method for preparing a sustained-release colorant includes the following steps:

[0041] S1. Add 100g of colorant powder (cobalt oxide) to anhydrous ethanol and ultrasonically disperse for 45min to obtain a uniform suspension with a solid content of 45%. Slowly add a mixed solution of 30g TEOS and 30mL ethanol at a rate of 1mL / min, while adjusting the pH to 9.5 with ammonia. Stir the mixture at 450rpm for 6h at room temperature, let it stand for 14h, collect it by centrifugation, dry it at 80℃, grind it through a 400-mesh sieve, and obtain the intermediate.

[0042] S2. Disperse the intermediate in an ethanol / water solution (V 乙醇 V 水In a mixture of S1 and TEOS, aluminum nitrate (Al(NO3)3·9H2O, 18.01 g) with a Si / Al molar ratio of 3:1 to that in S1 was added; after ultrasonic dispersion for 50 min, 38% urea solution was added dropwise at 62℃, the pH was controlled at 8.5, the mixture was allowed to stand for 8 h, centrifuged and collected, and calcined at 500℃ for 1.5 h to obtain a semi-finished product;

[0043] S3. Under nitrogen protection, 100g of the colorant semi-finished product was added to 5000mL of toluene, 30mLODS and 6mL of glacial acetic acid were added dropwise, and the mixture was stirred and refluxed at 80℃ for 10h. After centrifugation, washing, vacuum drying at 60℃ for 15h, and annealing at 160℃ for 2h, the slow-release cobalt oxide colorant was obtained.

[0044] Preparation Example 2

[0045] A method for preparing a sustained-release colorant includes the following steps:

[0046] S1. Add 100g of colorant powder (titanium oxide) to anhydrous ethanol and ultrasonically disperse for 45min to obtain a uniform suspension with a solid content of 45%. Slowly add a mixed solution of 25g TEOS and 30mL ethanol at a rate of 1mL / min, while adjusting the pH to 9.5 with ammonia. Stir the mixture at 450rpm for 6h at room temperature, let it stand for 14h, collect it by centrifugation, dry it at 80℃, grind it through a 400-mesh sieve, and obtain the intermediate.

[0047] S2. Disperse the intermediate in an ethanol / water solution (V 乙醇 V 水 In a mixture of S1 and TEOS, aluminum nitrate (Al(NO3)3·9H2O, 15.01 g) with a Si / Al molar ratio of 3:1 to that in S1 was added to the mixture. After ultrasonic dispersion for 50 min, 38% urea solution was added dropwise at 62℃, the pH was controlled at 8.5, the mixture was allowed to stand for 8 h, centrifuged and collected, and calcined at 500℃ for 1.5 h to obtain a semi-finished product.

[0048] S3. Under nitrogen protection, 100g of the colorant semi-finished product was added to 5000mL of toluene, 30mLODS and 6mL of glacial acetic acid were added dropwise, and the mixture was stirred and refluxed at 80℃ for 10h. After centrifugation, washing, vacuum drying at 60℃ for 15h, and annealing at 160℃ for 2h, the slow-release cobalt oxide colorant was obtained.

[0049] Preparation Example 3

[0050] A method for preparing a sustained-release colorant includes the following steps:

[0051] S1. Add 100g of colorant powder (cerium oxide) to anhydrous ethanol and ultrasonically disperse for 45min to obtain a uniform suspension with a solid content of 45%. Slowly add a mixed solution of 35g TEOS and 30mL ethanol at a rate of 1mL / min, while adjusting the pH to 9.5 with ammonia. Stir the mixture at 450rpm for 6h at room temperature, let it stand for 14h, collect it by centrifugation, dry it at 80℃, grind it through a 400-mesh sieve, and obtain the intermediate.

[0052] S2. Disperse the intermediate in an ethanol / water solution (V 乙醇 V 水 In a mixture of S1 and TEOS, aluminum nitrate (Al(NO3)3·9H2O, 20.01 g) with a Si / Al molar ratio of 3:1 to that in S1 was added to the mixture. After ultrasonic dispersion for 50 min, 38% urea solution was added dropwise at 62℃, the pH was controlled at 8.5, the mixture was allowed to stand for 8 h, centrifuged and collected, and calcined at 500℃ for 1.5 h to obtain a semi-finished product.

[0053] S3. Under nitrogen protection, 100g of the colorant semi-finished product was added to 5000mL of toluene, 30mLODS and 6mL of glacial acetic acid were added dropwise, and the mixture was stirred and refluxed at 80℃ for 10h. After centrifugation, washing, vacuum drying at 60℃ for 15h, and annealing at 160℃ for 2h, the slow-release cobalt oxide colorant was obtained.

[0054] Example 1

[0055] A colored dry granule is composed of a frit base material and a slow-release colorant prepared in Preparation Example 1 in a weight ratio of 100:4, wherein the frit base material comprises the following components by mass fraction: SrO: 4%; Al2O3: 13%; CaO: 8%; MgO: 2.5%; K2O: 4%; Na2O: 3%; BaO: 6%; ZnO: 8%; SiO2: balance;

[0056] The method for preparing the colored dry granules includes the following steps:

[0057] The frit base material was melted at 1500℃ to obtain a homogeneous liquid phase, which was then quenched in water, dried to remove moisture, and pulverized to 80 mesh. The slow-release colorant prepared in Preparation Example 1 was then added, melted at 1450℃, quenched in water, dried, and sieved to obtain colored dry granules.

[0058] Example 2

[0059] A type of colored dry granules, differing from Example 1 only in that the slow-release colorant is prepared from Preparation Example 2.

[0060] Example 3

[0061] A type of colored dry granules, differing from Example 1 only in that the slow-release colorant is prepared from Preparation Example 3.

[0062] Example 4

[0063] A colored dry granule, differing from Example 1 only in that the weight ratio of the frit base material to the slow-release colorant prepared in Preparation Example 1 is 100:0.5.

[0064] Example 5

[0065] A colored dry granule, differing from Example 1 only in that the weight ratio of the frit base material to the slow-release colorant prepared in Example 1 is 100:8.

[0066] Comparative Preparation Example 1

[0067] A method for preparing a sustained-release colorant differs from that in Preparation Example 1 in that step S3 is omitted.

[0068] Comparative Preparation Example 2

[0069] A method for preparing a sustained-release colorant differs from that in Preparation Example 1 in that step S2 is omitted.

[0070] Comparative Example 1

[0071] A type of colored dry granules, differing from Example 1 only in that the slow-release colorant is prepared from Comparative Preparation Example 1.

[0072] Comparative Example 2

[0073] A type of colored dry granules, differing from Example 1 only in that the slow-release colorant is prepared from Comparative Preparation Example 2.

[0074] Comparative Example 3

[0075] A colored dry granule, differing from Example 1 only in that the slow-release colorant is replaced with cobalt oxide powder.

[0076] Performance tests were conducted on the colored dry granules prepared in Examples 1-5 and Comparative Examples 1-3:

[0077] The colored dry granules prepared in each implementation case were refined and passed through a 200-mesh sieve. 20 parts colored dry granules, 75 parts suspending agent, 4 parts water, 2 parts protective glaze, and 400 grams of defoamer (100 kg + 400 g) were added to the dry granule glaze and thoroughly mixed to obtain a colored dry granule glaze slurry. This slurry was then applied to the body containing the surface glaze layer using a glazing method to form a colored dry granule glaze layer with a glaze specific gravity of 1.18 g / cm³. 3 The flow rate is 32s, and the glaze application rate is 280g / m³. 2 Firing in a kiln at 1230℃, followed by edge grinding to obtain ceramic tile products;

[0078] (1) Color rendering index: Three parallel batches of the same batch of ceramic tile samples were prepared and placed at room temperature and 60°C humidity for 24 hours. Five different areas (avoiding the edges) were randomly selected on the surface of the ceramic tile using a colorimeter and tested. Brightness, Red-green bias The color difference ΔEab is calculated by taking the average value of the yellow and blue bias. The smaller the ΔE, the higher the color intensity.

[0079] (2) Lightfastness: Referring to GB / T 16422.3-2014, the ceramic tile samples were placed in an ultraviolet aging test chamber (UVB-313 lamp, simulating short-wave ultraviolet light), with the temperature controlled at 60±3℃ and the relative humidity at 50±5%, and continuously irradiated for 1000h (equivalent to 1-2 years outdoors). The Lab value was measured with a colorimeter every 200h, ΔE was calculated, and the gray scale was rated according to ISO 105-B02 (Level 5: no change; Level 1: severe fading).

[0080] (3) Weather resistance: Referring to GB / T 1865-2009, a xenon lamp aging test chamber (simulating full-spectrum sunlight) was used, and the cycle conditions were set as follows: 102 min of light exposure (blackboard temperature 63±3℃, relative humidity 50%) + 18 min of spraying (simulating rainfall), with a total exposure of 1000 h; the color difference ΔE was measured before and after the test.

[0081] (4) Gloss: Using a WGG60-E4 photometer, after turning on the instrument, first adjust the 0 gloss point and the 97.0 gloss point using a standard plate, and then place the gloss meter on the sample to be measured to obtain the gloss data.

[0082] The test results are shown in Table 1.

[0083] Table 1

[0084]

[0085] As can be seen from Table 1, the colored dry granules prepared by this invention have high color rendering, strong color stability (anti-fading ability), and excellent gloss, and have a wide range of applications.

[0086] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0087] The above-disclosed embodiments are merely a few specific examples of the present invention. However, the embodiments of the present invention are not limited thereto, and any variations that can be conceived by those skilled in the art should fall within the protection scope of the present invention.

Claims

1. A colored dry granule, characterized by, Composed of frit base material and slow-release colorant; The frit base material is melted at 1450-1550℃, quenched in water, dried to remove moisture, and pulverized to 40-80 mesh; then a slow-release colorant is added, melted at 1400-1500℃, quenched in water, dried, and sieved to obtain colored dry granules. The sustained-release colorant is prepared by the following steps: S1. The colorant is dispersed in ethanol, and a mixed solution of ethyl silicate and ethanol is added dropwise. At the same time, the pH is adjusted to 9-10 with ammonia. The mixture is stirred at room temperature for 5-8 hours, allowed to stand for 10-20 hours, and then centrifuged and dried to obtain the intermediate. S2. The intermediate is dispersed in a solvent, aluminum nitrate is added, and the mixture is ultrasonically dispersed until uniform. Urea solution is added dropwise at 60-65℃, and the pH is controlled at 8-9. The mixture is allowed to stand for 6-10 hours, and then centrifuged and calcined to obtain the semi-finished product. S3. Under nitrogen protection, the semi-finished product is added to toluene, and octadecyltrimethoxysilane and glacial acetic acid are added dropwise. The mixture is stirred and refluxed at 75-85℃ for 8-12 hours, centrifuged, washed, vacuum dried and annealed to obtain the slow-release colorant. The colorant is one or a combination of several of the following: cobalt oxide, copper oxide, iron oxide, cerium oxide, zirconium oxide, titanium oxide, praseodymium oxide, manganese oxide, nickel oxide, and chromium oxide. In step S2, the calcination temperature is 500℃ and the calcination time is 1-3 hours; In step S3, the annealing temperature is 140-180℃ and the annealing time is 1-3h.

2. The colored dry granule according to claim 1, wherein The weight ratio of the frit base material to the slow-release colorant is 100:0.5-8.

3. The colored dry granule according to claim 1, wherein The frit base material comprises the following components by mass fraction: SrO: 0-8%; Al2O3: 12-15%; CaO: 7-10%; MgO: 1-4%; K2O: 3.5-5.5%; Na2O: 2-4.5%; BaO: 0.5-8.5%; ZnO: 4-10%; SiO2: Balance.

4. The colored dry granules according to claim 1, characterized in that, In S1, the weight ratio of the colorant to ethyl silicate is 100:25-35.

5. The colored dry granules according to claim 1, characterized in that, In S1, the dropping rate of the mixed solution of ethyl silicate and ethanol is 1-1.5 mL / min.

6. The colored dry granules according to claim 1, characterized in that, The molar ratio of ethyl silicate to aluminum nitrate is 2-4:

1.

7. The colored dry granules according to claim 1, characterized in that, In S3, the ratio of the semi-finished product, octadecyltrimethoxysilane, toluene, and glacial acetic acid is 1g:0.2-0.4mL:50mL:0.04-0.1mL.

8. A method for preparing colored dry granules, used to prepare the colored dry granules as described in any one of claims 1-7, characterized in that, Includes the following steps: The frit base material is melted at 1450-1550℃, quenched in water, dried to remove moisture, and pulverized to 40-80 mesh; then a slow-release colorant is added, melted at 1400-1500℃, quenched in water, dried, and sieved to obtain colored dry granules.

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