Self-cleaning ceramic roller and preparation method thereof

Abstract

This invention relates to the field of kiln materials, specifically to a self-cleaning ceramic roller and its preparation method. The self-cleaning ceramic roller includes a roller substrate, and a buffer layer and a self-cleaning layer sequentially disposed on the outer surface of the roller substrate; the buffer layer is obtained by curing an undercoat, and the difference between the thermal expansion coefficient of the buffer layer and the thermal expansion coefficient of the roller substrate is ≤2×10⁻⁶. ‑6 / ℃. Implementing this invention can endow ceramic rollers with a self-cleaning function, thereby effectively reducing the amount of nails adhering to the ceramic rollers in various temperature zones and extending their service life.

Description

Technical Field

[0001] This invention belongs to the field of kiln materials, and particularly relates to a self-cleaning ceramic roller and its preparation method. Background Technology

[0002] Ceramic rollers are the conveying devices in roller kilns, primarily used to transport products to be fired through the various temperature zones of the kiln for firing. Currently, a significant challenge in the use of ceramic rollers is the "rod nail" problem. Rod nails are deposits that gradually accumulate on ceramic rollers during use, significantly shortening their lifespan and causing product defects. For example, in ceramic tile production, rod nails are a key contributing factor to defects such as tile deformation, reduced surface flatness, and color differences (uneven color distribution).

[0003] Research has revealed fundamental differences in the formation mechanisms of nails in different temperature zones. For ceramic wall and floor tile roller kilns, in the low-to-medium temperature zone (approximately 400℃~800℃), the brick slurry and raw powder readily interact and deposit nails in a humid, sulfur-containing atmosphere. In the high-temperature zone (≥900℃), the softened raw material and molten glaze flow, adhere, and may even react with the ceramic rollers to form nails. Currently, nail deposition rates are rapid and have a significant impact in the low-to-medium temperature zone, hence the relatively large amount of research in this field. For example, the applicant previously proposed a corrosion-resistant ceramic roller coating and its preparation method (ZL202011633269.5), which can effectively solve the nail problem in the high and low box areas (i.e., the low-to-medium temperature zone). However, during application, the applicant found that it has a short lifespan and is difficult to effectively reduce nail adhesion in high-temperature zones. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a self-cleaning ceramic roller bar, which can reduce the amount of rod nails adhering in various temperature ranges and significantly extend the service life of the ceramic roller bar.

[0005] Another technical problem that this invention aims to solve is to provide a method for preparing a self-cleaning ceramic roller.

[0006] To solve the above-mentioned technical problems, the present invention discloses a self-cleaning ceramic roller, which includes a roller base, a buffer layer and a self-cleaning layer sequentially disposed on the outer surface of the roller base;

[0007] The buffer layer is formed by curing the base coating, and the difference between the coefficient of thermal expansion of the buffer layer and the coefficient of thermal expansion of the roller substrate is ≤2×10. -6 / ℃.

[0008] As an improvement to the above technical solution, the underlying coating includes a second base material and a second dispersant; the weight ratio of the second base material and the second dispersant is (2~5):(5~8).

[0009] The second base material includes second alumina micro powder, second titanium dioxide, boron nitride, and silicon carbide; or

[0010] The second base material includes second alumina micro powder, calcium carbonate, boron nitride, and second titanium dioxide; or

[0011] The second base material includes second alumina micro powder, calcium carbonate, boron nitride, and cordierite.

[0012] As an improvement to the above technical solution, the roller substrate is a silicon carbide roller, and the second base material comprises the following raw materials in parts by weight:

[0013] The second alumina micro powder consists of 20 to 40 parts, the second titanium dioxide consists of 2 to 10 parts, the boron nitride consists of 20 to 50 parts, and the silicon carbide consists of 10 to 30 parts; the total weight of the second alumina micro powder, the second titanium dioxide, the boron nitride, and the silicon carbide is 100 parts.

[0014] As an improvement to the above technical solution, the roller matrix is ​​a cordierite-mullite roller, and the second base material comprises the following raw materials in parts by weight:

[0015] The second alumina micro powder consists of 10 to 30 parts, calcium carbonate 2 to 10 parts, boron nitride 10 to 40 parts, and cordierite 20 to 40 parts; the total weight of the second alumina micro powder, calcium carbonate, boron nitride, and cordierite is 100 parts.

[0016] As an improvement to the above technical solution, the roller matrix is ​​a corundum-mullite roller, and the second base material comprises the following raw materials in parts by weight:

[0017] The mixture consists of 30 to 60 parts of alumina micro powder, 2 to 10 parts of calcium carbonate, 20 to 50 parts of boron nitride, and 5 to 10 parts of titanium dioxide; the total weight of the alumina micro powder, calcium carbonate, boron nitride, and titanium dioxide is 100 parts.

[0018] As an improvement to the above technical solution, the particle size of the second alumina micro powder is 1μm~2μm; and / or

[0019] The particle size of the second titanium oxide is 1 μm to 4 μm; and / or

[0020] The boron nitride has a particle size of 50 nm to 500 nm; and / or

[0021] The silicon carbide has a particle size of 3 μm to 6 μm; and / or

[0022] The cordierite has a grain size of 4μm to 10μm; and / or

[0023] The calcium carbonate has a particle size ≤48μm.

[0024] As an improvement to the above technical solution, the thickness of the buffer layer is ≥0.05mm.

[0025] As an improvement to the above technical solution, the second dispersion includes water and a dispersant;

[0026] The dispersant is selected from one or more of sodium tripolyphosphate, sodium citrate, sodium alginate, SN-5040, and BYK-163;

[0027] The weight ratio of water to dispersant is (200~500):1.

[0028] As an improvement to the above technical solution, the self-cleaning layer is obtained by curing a surface coating, the surface coating comprising a first base material and a first dispersion material; the weight ratio of the first base material to the first dispersion material is (1~2):(8~9).

[0029] The first base material comprises the following raw materials in parts by weight:

[0030] The ingredients are: 50-80 parts hexagonal boron nitride, 10-30 parts lamellar corundum, and 5-20 parts alumina micro powder; the total weight of the hexagonal boron nitride, lamellar corundum, and alumina micro powder is 100 parts.

[0031] As an improvement to the above technical solution, the first dispersion comprises the following raw materials in parts by weight:

[0032] 40-60 parts of polyurethane acrylate, 5-18 parts of photoinitiator, 8-20 parts of diluent, and 1-8 parts of additives;

[0033] The thickness of the self-cleaning layer is ≤0.5mm.

[0034] As an improvement to the above technical solution, the photoinitiator is a mixture of photoinitiator Irgacure 2959 and photoinitiator ITX, wherein the weight ratio of photoinitiator Irgacure 2959 to photoinitiator ITX is (1~2):1; or

[0035] The photoinitiator is selected as a mixture of photoinitiator Irgacure 2959 and photoinitiator EDAB, wherein the weight ratio of photoinitiator Irgacure 2959 to photoinitiator EDAB is (1~2):1; and / or

[0036] The diluent is a mixture of ethoxylated trimethylolpropane triacrylate and dipentaerythritol hexaacrylate, wherein the weight ratio of ethoxylated trimethylolpropane triacrylate to dipentaerythritol hexaacrylate is (1~2):1; and / or

[0037] The additive is a mixture of ethylene glycol butyl ether and isopropanol, with a weight ratio of ethylene glycol butyl ether to isopropanol of (1.2~5):1.

[0038] As an improvement to the above technical solution, the thickness of the buffer layer is 0.1mm~0.3mm;

[0039] The thickness of the self-cleaning layer is 0.1mm to 0.3mm.

[0040] As an improvement to the above technical solution, the particle size of the hexagonal boron nitride is 20nm~100nm; and / or

[0041] The particle size of the platy corundum is 1μm~10μm; and / or

[0042] The particle size of the first alumina micro powder is 1μm~2μm.

[0043] Accordingly, the present invention also discloses a method for preparing a self-cleaning ceramic roller, which includes:

[0044] A base coat is applied to the surface of the roller substrate and cured to form a buffer layer;

[0045] A surface coating is applied to the buffer layer and cured to form a self-cleaning layer.

[0046] As an improvement to the above technical solution, in the step of coating the buffer layer with a surface coating and curing it to form a self-cleaning layer:

[0047] The surface coating is cured by ultraviolet light. The process parameters for ultraviolet curing include: light intensity of 80 mW / cm². 2 ~120mW / cm 2 The exposure time is 10s to 30s.

[0048] As an improvement to the above technical solution, the step of coating the roller substrate with a base layer and curing it to form a buffer layer includes:

[0049] The surface of the roller substrate is wetted, and then a base coat is sprayed to form a first coating.

[0050] The first coating is dried to a preset moisture content to obtain the buffer layer;

[0051] The preset moisture content is 0.5wt%~2wt%.

[0052] Implementing this invention has the following beneficial effects:

[0053] In one embodiment of the present invention, a self-cleaning ceramic roller includes a roller substrate and a buffer layer and a self-cleaning layer sequentially disposed on its outer surface; the buffer layer is obtained by curing an undercoat, and the difference between the coefficient of thermal expansion of the buffer layer and the coefficient of thermal expansion of the roller substrate is ≤2×10. -6 / ℃; The buffer layer and the roller substrate have good thermal compatibility and bonding force, effectively absorbing and buffering thermal stress, preventing cracking and peeling of the self-cleaning layer caused by stress concentration. This allows the self-cleaning layer to be used in medium and low temperature zones as well as high temperature zones. The self-cleaning layer effectively reduces impurity adsorption and remains stable in high-temperature and highly corrosive environments. This double-layer structure effectively reduces the amount of rod nails adhering to the ceramic rollers in each temperature zone, greatly improving the service life and reliability of the ceramic rollers. Detailed Implementation

[0054] To facilitate understanding of the present invention, it will be described in more detail below. However, it should be understood that the present invention can be implemented in many different forms and is not limited to the embodiments or examples described herein. Rather, these embodiments or examples are provided to make the disclosure of the present invention more thorough and complete.

[0055] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the specification of this invention is for the purpose of describing particular embodiments or examples only and is not intended to limit the invention. The optional range of the term "and / or" as used herein includes any one of two or more of the related listed items, as well as any and all combinations of the related listed items, including any two related listed items, any more related listed items, or a combination of all related listed items.

[0056] The following embodiments are provided for the purpose of illustrating various embodiments of the present invention and are not intended to limit the invention in any way. Those skilled in the art will understand that variations and other uses as defined in the claims are included within the spirit and scope of the invention. Unless otherwise specified, the materials, reagents, etc., used in the following embodiments are commercially available.

[0057] In this invention, terms such as "first aspect" and "second aspect" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or quantity, nor should they be construed as implicitly indicating the importance or quantity of the indicated technical features.

[0058] In this invention, the technical features described in an open-ended manner include both closed-ended technical solutions composed of the listed features and open-ended technical solutions that include the listed features.

[0059] Unless otherwise specified, the percentage content involved in this invention refers to mass percentage for solid-liquid mixtures and solid-phase-solid mixtures, and volume percentage for liquid-phase-liquid mixtures.

[0060] Unless otherwise specified, all percentage concentrations mentioned in this invention refer to the final concentration. The final concentration refers to the proportion of the added component in the system after the addition of that component.

[0061] Unless otherwise specified, the temperature parameters in this invention can be either constant temperature processing or processing within a certain temperature range. The constant temperature processing allows temperature fluctuations within the precision range controlled by the instrument.

[0062] As a first aspect of the present invention, a self-cleaning ceramic roller is disclosed, comprising a roller substrate, a buffer layer and a self-cleaning layer sequentially disposed on the outer surface of the roller substrate. The buffer layer is obtained by curing an undercoat, and the difference between the coefficient of thermal expansion of the buffer layer and the coefficient of thermal expansion of the roller substrate is ≤2×10⁻⁶. -6 / ℃. Based on the aforementioned self-cleaning ceramic rollers, firstly, the self-cleaning layer significantly reduces the possibility of various contaminants adhering to the ceramic rollers in the roller kiln, improving self-cleaning performance, greatly reducing the probability of rod stud formation, lowering the difficulty of cleaning and maintaining the ceramic rollers, and increasing the yield of ceramic products. Secondly, by setting a buffer layer with good thermal compatibility with the roller substrate, thermal stress can be effectively absorbed and buffered, preventing stress concentration from causing cracking and peeling of the self-cleaning layer. This allows the self-cleaning layer to be applied in both medium and low temperature zones and high temperature zones. This double-layer structure effectively reduces the amount of rod studs adhering to the ceramic rollers in each temperature zone, greatly improving the service life and reliability of the ceramic rollers.

[0063] Specifically, the thickness of the buffer layer is ≥0.05mm. If its thickness is <0.05mm, the buffering effect is poor, resulting in a shorter service life of the ceramic roller in the high-temperature zone. Preferably, in some embodiments, the thickness of the buffer layer is 0.05mm~0.5mm, exemplarily 0.08mm, 0.15mm, 0.22mm, 0.3mm or 0.4mm, but not limited thereto. Preferably, it is 0.1mm~0.3mm.

[0064] Specifically, the difference between the thermal expansion coefficient of the buffer layer and the thermal expansion coefficient of the roller substrate is the absolute value of the difference. That is, the thermal expansion coefficient of the buffer layer can be greater than that of the roller substrate, or the thermal expansion coefficient of the buffer layer can be less than that of the roller substrate.

[0065] Specifically, in some embodiments, the undercoat includes a second base material and a second dispersant; the weight ratio of the second base material to the second dispersant is (2~5):(5~8); wherein, the second dispersant may be a water-based aqueous dispersion system, such as a dispersion system formed by water and a dispersant or water and an aqueous resin. The dispersant may be carboxymethyl cellulose, sodium alginate, but is not limited to these. The aqueous resin may be an aqueous epoxy resin, an aqueous polyurethane, but is not limited to these. The second dispersant may also be an organic solvent-based dispersion system, such as a dispersion system formed by an organic solvent and epoxy resin, polyurethane resin, phenolic resin, acrylic resin, alkyd resin, etc., but is not limited to these. For example, the weight ratio of the second base material to the second dispersant is 3.5:6.5, 4:6, 4.5:5.5, or 4.8:5.2, but is not limited to these.

[0066] Specifically, the second base material includes second alumina micro powder, second titanium dioxide, boron nitride and silicon carbide; or the second base material includes second alumina micro powder, calcium carbonate, boron nitride and second titanium dioxide; or the second base material includes second alumina micro powder, calcium carbonate, boron nitride and cordierite.

[0067] More specifically, in some embodiments, the roller substrate is a silicon carbide roller, and the second base material comprises the following raw materials in parts by weight:

[0068] 20-40 parts of alumina micro powder, 2-10 parts of titanium dioxide, 20-50 parts of boron nitride, and 10-30 parts of silicon carbide; the total weight of alumina micro powder, titanium dioxide, boron nitride, and silicon carbide is 100 parts.

[0069] More specifically, in some embodiments, the roller matrix is ​​a cordierite-mullite roller, and the second base material comprises the following raw materials in parts by weight:

[0070] The ingredients are: 10-30 parts of alumina micro powder, 2-10 parts of calcium carbonate, 10-40 parts of boron nitride, and 20-40 parts of cordierite; the total weight of the alumina micro powder, calcium carbonate, boron nitride, and cordierite is 100 parts.

[0071] More specifically, in some embodiments, the roller matrix is ​​a corundum-mullite roller, and the second base material comprises the following raw materials in parts by weight:

[0072] 30-60 parts of alumina micro powder, 2-10 parts of calcium carbonate, 20-50 parts of boron nitride, and 5-10 parts of titanium dioxide; the total weight of alumina micro powder, calcium carbonate, boron nitride, and titanium dioxide is 100 parts.

[0073] Specifically, in the second base material, the second alumina micro powder refers to micron- or submicron-sized powder obtained from industrial alumina through mechanical grinding and / or high-temperature calcination, with a particle size of 1μm to 5μm. Preferably, it is 1μm to 2μm.

[0074] Specifically, in the second base material, the second titanium dioxide is rutile titanium dioxide or anatase titanium dioxide, preferably rutile titanium dioxide, to prevent thermal stress concentration caused by lattice transformation at high temperatures. The particle size of the second titanium dioxide is 1μm to 5μm, preferably 1μm to 4μm.

[0075] Specifically, in the second base material, boron nitride can be hexagonal boron nitride or cubic boron nitride, and it can be nanoparticles or submicron-sized powders. Preferably, the particle size of boron nitride is 50 nm to 800 nm, more preferably 50 nm to 500 nm.

[0076] Specifically, in the second base material, the particle size of silicon carbide is 3μm~10μm, preferably 3μm~6μm.

[0077] Specifically, in the second base material, the particle size of calcium carbonate is ≤48μm, preferably 5μm~30μm.

[0078] Specifically, in the second base material, the particle size of cordierite is 4μm~20μm, preferably 4μm~10μm.

[0079] The buffer layer prepared based on the above-mentioned base coating not only has good thermal compatibility with roller substrates of different textures, but also has good corrosion resistance. In synergy with the self-cleaning layer, it significantly extends the service life of ceramic rollers.

[0080] Preferably, in some embodiments, the second dispersion comprises water and a dispersant; the dispersant is selected from one or more of sodium tripolyphosphate, sodium citrate, sodium alginate, SN-5040 (Nopco), and BYK-163 (BYK); the weight ratio of water to dispersant is (200~500):1, exemplarily 250:1, 300:1, 350:1, 400:1 or 450:1, but not limited thereto.

[0081] Specifically, the self-cleaning layer is obtained by curing a surface coating, which may be the corrosion-resistant ceramic roller coating in ZL202011633269.5, but is not limited thereto. Preferably, in some embodiments, the surface coating includes a first base material and a first dispersion; the weight ratio of the first base material to the first dispersion is (1~2):(8~9);

[0082] The first base material comprises the following raw materials in parts by weight:

[0083] The formulation consists of 50-80 parts hexagonal boron nitride, 10-30 parts lamellar corundum, and 5-20 parts alumina micropowder; the total weight of hexagonal boron nitride, lamellar corundum, and alumina micropowder is 100 parts. This formulation creates a self-cleaning surface coating, reducing the likelihood of adhesion between the brick base slurry (powder), brick powder, molten glaze, and partially molten brick body. Furthermore, this surface coating exhibits excellent thermal stability, maintaining good mechanical strength and structural stability across various temperature ranges (400℃~1300℃). This results in a long service life for the self-cleaning layer itself, which in turn extends the service life of the ceramic roller.

[0084] Specifically, the first dispersion can be a water-based aqueous dispersion system, such as a dispersion system formed by water and a dispersant or water and an aqueous resin. The dispersant can be carboxymethyl cellulose, sodium alginate, etc., but is not limited to these. The aqueous resin can be an aqueous epoxy resin, an aqueous polyurethane, etc., but is not limited to these. The first dispersion can also be an organic solvent-based dispersion system, such as a dispersion system formed by an organic solvent and epoxy resin, polyurethane resin, phenolic resin, acrylic resin, alkyd resin, etc., but is not limited to these. For example, the weight ratio of the first base material to the first dispersion is 1.2:8.8, 1.4:8.6, 1.6:8.4, or 1.8:8.2, but is not limited to these.

[0085] Specifically, in the surface coating, hexagonal boron nitride exhibits a layered structure. Working in conjunction with lamellar corundum, it forms a slightly rough, hydrophobic surface, reducing the adhesion of molten glaze and semi-molten brick blanks to the ceramic roller surface. This slightly rough structure also lowers the surface friction coefficient of the self-cleaning layer formed by the self-cleaning ceramic roller coating, making it easier for the brick base slurry (powder), brick powder, molten glaze, and partially molten brick blanks to slide when in contact with the self-cleaning layer, reducing the possibility of adhesion. Combined, these factors achieve a self-cleaning effect on the ceramic roller surface, significantly extending the service life of the ceramic roller. Furthermore, hexagonal boron nitride possesses excellent chemical stability, resisting high temperatures, strong acids, strong alkalis, and oxidation. It can resist corrosion from molten glaze and partially softened brick blanks under high temperatures, and also resist corrosion from various corrosive gases in high and low temperature chambers (400℃~800℃). Hexagonal boron nitride also exhibits excellent thermal stability, with a coefficient of thermal expansion of only 2×10⁻⁶. -6 / ℃~6×10 -6The temperature range of / ℃ effectively maintains the stability of the self-cleaning layer formed by the self-cleaning roller coating, preventing it from peeling off. This significantly extends the service life after a single coat and prevents large-scale adhesion of rods due to the self-cleaning layer peeling off. Specifically, the amount of hexagonal boron nitride used is 50 to 80 parts. If the amount is too high, the overall hardness of the self-cleaning layer will be low, making it prone to wear and causing it to wear off during use. If the amount is too low, impurities will still easily adhere, forming rods. For example, the amount of hexagonal boron nitride used is 50, 55, 60, or 65 parts, but is not limited to these. Preferably, it is 60 to 80 parts.

[0086] Specifically, in the surface coating, lamellar corundum is produced by remelting industrial alumina in an electric furnace. The crystals of lamellar corundum are arranged in a two-dimensional, plate-like pattern. The micro-roughened surface formed by the interpenetration of lamellar corundum and hexagonal boron nitride significantly improves its self-cleaning properties. Furthermore, lamellar corundum itself possesses excellent refractoriness and thermal shock resistance, especially with a Mohs hardness of 9. When combined with hexagonal boron nitride (Mohs hardness only 2-3), it reduces wear on the self-cleaning layer and extends its service life. Specifically, the amount of lamellar corundum used is 10 to 30 parts. If the amount is too large, the surface roughness will be too high, which may lead to excessive rod-like defects in high-temperature areas; if the amount is too small, the self-cleaning performance will be weak, and the self-cleaning layer will be easily worn. Examples of lamellar corundum amounts include 12, 16, 20, 24, or 28 parts, but these are not limited to these. Preferably, the amount of flake corundum used is 10 to 25 parts, more preferably 10 to 20 parts.

[0087] Specifically, in the surface coating, the primary alumina micro powder refers to micron- or submicron-sized powder obtained from industrial alumina through mechanical grinding and / or high-temperature calcination. It has high hardness and strong thermal stability, and can be used as a filler matrix, working in conjunction with hexagonal boron nitride and lamellar corundum to improve thermal shock resistance and corrosion resistance. The amount of primary alumina micro powder used is 5 to 20 parts, exemplarily 8, 11, 14, 17, or 19 parts, but not limited to these. Preferably, it is 10 to 20 parts.

[0088] Specifically, in the surface coating, hexagonal boron nitride is a nanoparticle, meaning its particle size is <1μm, and it exhibits a layered structure at the microscopic level. Preferably, in some embodiments, the particle size of hexagonal boron nitride is 20nm~200nm, more preferably 20nm~100nm. The boron nitride content in the hexagonal boron nitride is ≥99.9wt%.

[0089] Specifically, in the surface coating, the particle size of the flake-shaped corundum is 1μm~50μm, its Al2O3 content is ≥99wt%, and the total content of Fe2O3, Na2O, MgO, K2O, and CaO is ≤0.5wt%. Preferably, the particle size of the flake-shaped corundum is 1μm~10μm, its Al2O3 content is ≥99.2wt%, and the total content of Fe2O3, Na2O, MgO, K2O, and CaO is ≤0.42wt%. This type of flake-shaped corundum has stronger high-temperature resistance, which is beneficial to further improving the stability of the self-cleaning layer.

[0090] Specifically, in the surface coating, the particle size of the first alumina micro powder is 1μm to 10μm, and its Al2O3 content is ≥99wt%. Preferably, the particle size of the first alumina micro powder is 1μm to 2μm, and its Al2O3 content is ≥99.3wt%.

[0091] Preferably, in some embodiments, the first base material further includes chromium oxide and titanium oxide, but is not limited thereto. Chromium oxide can further improve corrosion resistance. Titanium oxide has high hardness and high temperature resistance; when used together with the first alumina micropowder as a matrix, it can significantly optimize the thermal shock resistance and corrosion resistance of the self-cleaning layer.

[0092] Preferably, in some embodiments, the first base material is composed of the following raw materials in parts by weight:

[0093] The formula comprises 50-80 parts hexagonal boron nitride, 10-20 parts lamellar corundum, 10-20 parts alumina micropowder, and 5-10 parts titanium dioxide; the total weight of the hexagonal boron nitride, lamellar corundum, alumina micropowder, and titanium dioxide is 100 parts. This formulation further extends the service life of the self-cleaning layer, especially in high-temperature regions. Specifically, the particle size of the titanium dioxide is 1μm-5μm, preferably 2μm-5μm. Specifically, the titanium dioxide can be rutile or anatase, but is not limited to these. Preferably, the titanium dioxide is rutile, which generates less thermal stress at high temperatures.

[0094] Preferably, in some embodiments, the first dispersion comprises the following raw materials in parts by weight:

[0095] The composition comprises 40-60 parts polyurethane acrylate (PUA), 5-18 parts photoinitiator, 8-20 parts diluent, and 1-8 parts additives. Based on the above-mentioned first dispersion, the self-cleaning ceramic roller coating can be cured by ultraviolet light curing, improving production efficiency. This allows for the rapid formation of a self-cleaning layer on the ceramic roller without stopping the roller kiln, enabling rapid surface renewal and replacement of the ceramic roller, and extending the service life of the ceramic roller. Furthermore, it should be noted that when using the above-mentioned first dispersion, the thickness of the self-cleaning layer should be controlled to ≤0.5mm. If the thickness is too large, firstly, the organic matter in the first dispersion decomposes at high temperatures, which may temporarily affect the roller kiln atmosphere and the yield of ceramic products. Secondly, the cured self-cleaning layer will generate too many pores after the organic matter decomposes at high temperatures, which is detrimental to the stability of the self-cleaning layer. Preferably, the thickness of the self-cleaning layer is 0.1mm-0.3mm, more preferably 0.15mm-0.25mm.

[0096] For example, the amount of polyurethane acrylate (PUA) in the first dispersion is 42 parts, 44 parts, 46 parts, 48 ​​parts, 50 parts, 52 parts, 54 parts, 56 parts, or 58 parts, but is not limited thereto. Preferably, it is 50 to 60 parts.

[0097] The photoinitiator is selected from one or more of photoinitiator Irgacure 2959, photoinitiator ITX, and photoinitiator EDAB, but is not limited thereto. For example, the amount of photoinitiator used is 6 parts, 7 parts, 8 parts, 9 parts, 10 parts, 11 parts, 12 parts, 13 parts, or 14 parts, but is not limited thereto. Preferably, the photoinitiator is selected from photoinitiator Irgacure 2959 and photoinitiator ITX / EDAB, and the weight ratio of photoinitiator Irgacure 2959 to photoinitiator ITX / EDAB is (1~2):1. Alternatively, the photoinitiator is selected from a mixture of photoinitiator Irgacure 2959 and photoinitiator EDAB, and the weight ratio of photoinitiator Irgacure 2959 to photoinitiator EDAB is (1~2):1.

[0098] The diluent may be an organic solvent, but is not limited thereto. Preferably, the diluent is a mixture of ethoxylated trimethylolpropane triacrylate (EO-TMPTA) and dipentaerythritol hexaacrylate (DPHA), with a weight ratio of EO-TMPTA to DPHA of (1~2):1. Exemplarily, the amount of diluent used in the first dispersion is 8 parts, 10 parts, 12 parts, 14 parts, 16 parts, or 18 parts, but is not limited thereto.

[0099] Specifically, the first dispersion may also include some commonly used additives in the art, such as wetting agents, leveling agents, and defoamers, but is not limited to these. Among them, the wetting agent may be glycerol, alkyl polyoxyethylene ether, etc., but is not limited to these. Preferably, in some embodiments, the additive is a mixture of ethylene glycol butyl ether and isopropanol, with a weight ratio of ethylene glycol butyl ether to isopropanol of (1.2~5):1, but is not limited to this. This additive can create a gradient evaporation, reducing the risk of surface skinning. Exemplarily, the amount of additive in the first dispersion is 1 part, 2 parts, 3 parts, 4 parts, 5 parts, 6 parts, or 7 parts, but is not limited to this.

[0100] Accordingly, as a second aspect of the present invention, the present invention also provides a method for preparing the above-mentioned self-cleaning ceramic roller, comprising:

[0101] (1) Apply a base coat to the surface of the roller substrate and cure it to form a buffer layer;

[0102] Specifically, the base coat can be applied to the surface of the roller substrate by spraying, brushing, dipping, or other methods, but is not limited to these. Preferably, in some embodiments, the surface of the roller substrate is first moistened by spraying water, and then the base coat is sprayed to form a first coating layer; then the first coating layer is dried to a moisture content of 0.5wt% to 2wt%, thus obtaining a buffer layer.

[0103] (2) Apply a surface coating to the buffer layer and cure it to form a self-cleaning layer.

[0104] Specifically, the surface coating can be applied to the buffer layer by spraying, brushing, dipping, or other methods, but is not limited to these. After application, a self-cleaning layer is formed by light curing or heat curing. In some embodiments, the surface coating is cured by ultraviolet light curing; the process parameters for ultraviolet light curing include: a light intensity of 80 mW / cm². 2 ~120mW / cm 2 The exposure time is 10s to 30s. Specifically, the wavelength of the ultraviolet light can be 300nm to 380nm, exemplarily 313nm, 365nm, or 385nm, but is not limited to these. Based on this photocuring process, the curing speed can be improved and production efficiency can be accelerated.

[0105] The present invention will now be described with reference to specific embodiments:

[0106] Example 1

[0107] This embodiment provides a self-cleaning ceramic roller, which includes a roller substrate (corundum-mullite roller), and a buffer layer and a self-cleaning layer are sequentially disposed on the outer surface of the roller substrate. The thickness of the buffer layer is 0.2 mm, and the thickness of the self-cleaning layer is 0.3 mm.

[0108] The buffer layer is obtained by curing the base coating, which includes a second base material and a second dispersant. The formula of the second base material is as follows: 460g of alumina micro powder (1μm~2μm), 80g of titanium dioxide (1μm~4μm), 400g of cubic boron nitride (200nm~500nm), and 60g of calcium carbonate (10μm~40μm). The formula of the second dispersant is as follows: 12g of sodium citrate and 2500g of water. All the above raw materials are added to a ball mill according to the formula, ball-milled for 50 minutes, and then sieved to obtain the base coating.

[0109] The self-cleaning layer is obtained by curing a surface coating, which includes a first base material and a first dispersion. The formulation and preparation method of the first base material are as follows: 700g of hexagonal boron nitride (20nm~50nm), 200g of flake corundum (2μm~5μm), 100g of alumina micro powder (1μm~2μm), and 7500g of water are added to a ball mill, ball-milled for 30 minutes, then sieved, dried, and pulverized to obtain the first base material. The formulation and preparation method of the first dispersion are as follows: 5600g of polyurethane acrylate (PUA), 500g of photoinitiator Irgacure 2959, 250g of photoinitiator ITX, 1000g of diluent EO-TMPTA, 600g of diluent DPHA, 300g of ethylene glycol butyl ether, and 200g of isopropanol are mixed evenly to obtain the first dispersion. The surface coating is obtained by mixing and grinding the first base material and the first dispersion.

[0110] The method for preparing the self-cleaning ceramic roller in this embodiment is as follows:

[0111] (1) Spray water to wet the roller substrate, spray the base coat, and dry it until the moisture content is 1wt%~2wt% to obtain the buffer layer;

[0112] (2) Apply the surface coating 2 to 3 times to the buffer layer and cure it under ultraviolet light to form a self-cleaning layer. The ultraviolet curing process parameters include: ultraviolet wavelength of 365nm and light intensity of 100mW / cm². 2 The exposure time is 20 seconds.

[0113] Example 2

[0114] This embodiment provides a self-cleaning ceramic roller, which includes a roller substrate (corundum-mullite roller), and a buffer layer and a self-cleaning layer are sequentially disposed on the outer surface of the roller substrate. The thickness of the buffer layer is 0.2 mm, and the thickness of the self-cleaning layer is 0.3 mm.

[0115] The buffer layer is formed by curing the base coating, which includes a second base material and a second dispersant. The formula for the second base material is as follows: 460g of alumina micro powder (1μm~2μm), 80g of titanium dioxide (1μm~4μm), 400g of cubic boron nitride (200nm~500nm), and 60g of calcium carbonate (10nm~40μm). The formula for the second dispersant is as follows: 12g of sodium citrate and 2500g of water. All the above raw materials are added to a ball mill according to the formula, ball-milled for 50 minutes, and then sieved to obtain the base coating.

[0116] The self-cleaning layer is obtained by curing a surface coating, which includes a first base material and a first dispersion. The formulation and preparation method of the first base material are as follows: 700g of hexagonal boron nitride (20nm~50nm), 140g of flake corundum (2μm~5μm), 110g of alumina micro powder (1μm~2μm), 50g of titanium dioxide (1μm~4μm) and 7500g of water are added to a ball mill, ball milled for 30min, sieved, dried and pulverized to obtain the first base material. The formulation and preparation method of the first dispersion are as follows: 5200g of polyurethane acrylate (PUA), 580g of photoinitiator Irgacure 2959, 290g of photoinitiator EDAB, 1100g of diluent EO-TMPTA and 550g of diluent DPHA, 280g of ethylene glycol butyl ether and 150g of isopropanol are mixed evenly to obtain the first dispersion. The first base material and the first dispersion are mixed and ground to obtain the surface coating.

[0117] The method for preparing the self-cleaning ceramic roller in this embodiment is as follows:

[0118] (1) Spray water to wet the roller substrate, spray the base coat, and dry it until the moisture content is 1wt%~2wt% to obtain the buffer layer;

[0119] (2) Apply the surface coating 2 to 3 times to the buffer layer and cure it under ultraviolet light to form a self-cleaning layer. The ultraviolet curing process parameters include: ultraviolet wavelength of 365nm and light intensity of 100mW / cm². 2 The exposure time is 20 seconds.

[0120] Example 3

[0121] This embodiment provides a self-cleaning composite ceramic roller, which includes a roller substrate (cordierite-mullite roller), and a buffer layer and a self-cleaning layer are sequentially disposed on the outer surface of the roller substrate. The thickness of the buffer layer is 0.25 mm, and the thickness of the self-cleaning layer is 0.25 mm.

[0122] The buffer layer is obtained by curing the base coating, which includes a second base material and a second dispersant. The formula of the second base material is as follows: 250g of alumina micro powder (1μm~2μm), 50g of calcium carbonate (10μm~40μm), 350g of cubic boron nitride (200nm~500nm), and 350g of cordierite (4μm~8μm). The formula of the second dispersant is as follows: 14g of sodium tripolyphosphate and 2900g of water. All the above raw materials are added to a ball mill according to the formula, ball-milled for 50 minutes, and then sieved to obtain the base coating.

[0123] The self-cleaning layer is obtained by curing a surface coating, which includes a first base material and a first dispersion. The formulation and preparation method of the first base material are as follows: 650g of hexagonal boron nitride (20nm~80nm), 200g of flake corundum (1μm~4μm), 150g of alumina micro powder (1μm~2μm), and 7500g of water are added to a ball mill, ball-milled for 30 minutes, then sieved, dried, and pulverized to obtain the first base material. The formulation and preparation method of the first dispersion are as follows: 5000g of polyurethane acrylate (PUA), 600g of photoinitiator Irgacure 2959, 300g of photoinitiator ITX, 1200g of diluent EO-TMPTA, 600g of diluent DPHA, 300g of ethylene glycol butyl ether, and 100g of isopropanol are mixed evenly to obtain the first dispersion. The surface coating is obtained by mixing and grinding the first base material and the first dispersion.

[0124] The method for preparing the self-cleaning ceramic roller in this embodiment is as follows:

[0125] (1) Spray water to wet the roller substrate, spray the base coat, and dry it until the moisture content is 1wt%~2wt% to obtain the buffer layer;

[0126] (2) Apply the surface coating 2 to 3 times to the buffer layer and cure it under ultraviolet light to form a self-cleaning layer. The ultraviolet curing process parameters include: ultraviolet wavelength of 365nm and light intensity of 100mW / cm². 2 The exposure time is 15 seconds.

[0127] Example 4

[0128] This embodiment provides a self-cleaning composite ceramic roller, which includes a roller substrate (silicon carbide roller), and a buffer layer and a self-cleaning layer are sequentially disposed on the outer surface of the roller substrate. The thickness of the buffer layer is 0.3 mm, and the thickness of the self-cleaning layer is 0.2 mm.

[0129] The buffer layer is obtained by curing the base coating, which includes a second base material and a second dispersant. The formula of the second base material is as follows: 300g of second alumina micro powder (1μm~2μm), 60g of second titanium dioxide (1μm~4μm), 400g of cubic boron nitride (200nm~500nm), and 240g of silicon carbide (3μm~6μm). The formula of the second dispersant is as follows: 5g of BYK-163 and 2400g of water. All the above raw materials are added to a ball mill according to the formula, ball-milled for 50 minutes, and then sieved to obtain the base coating.

[0130] The self-cleaning layer is obtained by curing the surface coating. The surface coating includes a first base material and a first dispersion. The formulation and preparation method of the first base material are as follows: 700g of hexagonal boron nitride (20nm~60nm), 180g of flake corundum (1μm~5μm), 120g of alumina micro powder (1μm~2μm) and 7500g of water are added to a ball mill, ball-milled for 30min, then sieved, dried, and pulverized to obtain the first base material. The formulation and preparation method of the first dispersion are as follows: 5500g of polyurethane acrylate (PUA), 510g of photoinitiator Irgacure 2959, 260g of photoinitiator EDAB, 900g of diluent EO-TMPTA and 500g of diluent DPHA, 260g of ethylene glycol butyl ether, and 130g of isopropanol are mixed evenly to obtain the first dispersion. The surface coating is obtained by mixing and grinding the first base material and the first dispersion.

[0131] The method for preparing the self-cleaning ceramic roller in this embodiment is as follows:

[0132] (1) Spray water to wet the roller substrate, spray the base coat, and dry it until the moisture content is 1wt%~2wt% to obtain the buffer layer;

[0133] (2) Apply self-cleaning ceramic roller coating 2-3 times to the buffer layer and cure under ultraviolet light to form a self-cleaning layer. The ultraviolet curing process parameters include: ultraviolet wavelength of 365nm and light intensity of 100mW / cm². 2 The exposure time is 20 seconds.

[0134] Comparative Example 1

[0135] This comparative example provides a ceramic roller, which is a corundum-mullite roller with a protective layer on its surface. This protective layer is made of roller coating. The thickness of the protective layer is 0.4 mm. The roller coating includes a matrix component and a suspension component.

[0136] The matrix components, by weight, are: 4 parts of wurtzite-type boron nitride, 10 parts of aluminum chromium slag, 60 parts of fused white corundum, 21 parts of calcined alumina, and 5 parts of kaolin.

[0137] Among them, the maximum particle size of wurtzite-type boron nitride is 1.8 μm, and the BN content is 99.5 wt%; the Cr2O3 content in aluminum chromium slag is 18.4 wt%, the Al2O3 content is 76.5 wt%, and the solid solution content is 94 wt%; its maximum particle size is 35 μm; the Al2O3 content in fused white corundum is 99.5 wt%, the Fe2O3 content is 0.05 wt%, and the maximum particle size is 40 μm; the Al2O3 content in calcined alumina is 99.5 wt%, the Fe2O3 content is 0.05 wt%, and the maximum particle size is 4 μm; the Al2O3 content in kaolin is 34 wt%, the Fe2O3 content is 0.5 wt%, and the maximum particle size is 0.5 μm.

[0138] The formulation of the suspended component by weight is as follows: 40 parts water, 0.8 parts carboxymethyl cellulose, and 20 parts 50% aluminum dihydrogen phosphate.

[0139] The weight ratio of the matrix component to the suspension component is 4:6.

[0140] The ceramic roller in this comparative example is prepared by brushing a roller coating onto the roller substrate and then drying and curing it to form a protective layer.

[0141] Comparative Example 2

[0142] This comparative example provides a ceramic roller bar, which differs from Example 1 in that the ceramic roller bar does not have a buffer layer, but only forms a self-cleaning layer with a thickness of 0.4 mm.

[0143] Everything else is the same as in Example 1.

[0144] The ceramic rollers obtained in Examples 1-4 and Comparative Examples 1-2 were tested using the following methods: They were used in a conventional fully polished glazed kiln (firing temperature 1200℃-1210℃) at temperatures ranging from 500℃ to 1210℃; the MgO content in the brick slurry was 84%, and the CaO content was 1.8%. The condition of the rollers was monitored after 3, 6, and 9 months of use. Specifically, five ceramic rollers were taken from each temperature range, and after removing dust and other contaminants, they were weighed to evaluate the amount of roller adhesion. A completely uncoated corundum-mullite roller was used as a blank control. The specific results are shown in the table below.

[0145] Table 1. Stick adhesion amount (%) in each embodiment and comparative example

[0146]

[0147] In the table, "-" indicates that the rod has too much adhesive and must be replaced, making it difficult to measure the amount of adhesive.

[0148] As can be seen from the table, the self-cleaning ceramic roller of the present invention has a small amount of sticky rods adhering to it when used in various temperature zones, and has a long service life.

[0149] The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as the combination of these technical features does not contradict each other, it should be considered within the scope of this specification. The above embodiments only illustrate several implementation methods of the present invention to facilitate a specific and detailed understanding of the technical solution of the present invention, but should not be construed as limiting the scope of protection of the invention patent. It should be noted that for those skilled in the art, several modifications and improvements can be made without departing from the concept of the present invention, and these all fall within the protection scope of the present invention.

[0150] It should be understood that any technical solutions obtained by those skilled in the art based on the technical solutions provided in this invention through logical analysis, reasoning, or limited experimentation are all within the scope of protection of the appended claims. Therefore, the scope of protection of this patent should be determined by the content of the appended claims, and the specification can be used to interpret the content of the claims.

Claims

1. A self-cleaning ceramic roller, characterized in that, It includes a roller base, and a buffer layer and a self-cleaning layer sequentially disposed on the outer surface of the roller base; The buffer layer is obtained by curing the bottom coating, which includes a second base material and a second dispersion; the second base material includes second alumina micro powder, second titanium dioxide, boron nitride and silicon carbide; or the second base material includes second alumina micro powder, calcium carbonate, boron nitride and second titanium dioxide; or the second base material includes second alumina micro powder, calcium carbonate, boron nitride and cordierite; The difference between the thermal expansion coefficient of the buffer layer and the thermal expansion coefficient of the roller substrate is ≤2×10. -6 / ℃; The self-cleaning layer is obtained by curing a surface coating, which includes a first base material and a first dispersion material; the first base material includes hexagonal boron nitride, lamellar corundum, and first alumina micro powder.

2. The self-cleaning ceramic roller as described in claim 1, characterized in that, The weight ratio of the second base material to the second dispersion is (2~5):(5~8).

3. The self-cleaning ceramic roller as described in claim 2, characterized in that, The roller base is a silicon carbide roller, and the second base material comprises the following raw materials in parts by weight: The second alumina micro powder consists of 20 to 40 parts, the second titanium dioxide consists of 2 to 10 parts, the boron nitride consists of 20 to 50 parts, and the silicon carbide consists of 10 to 30 parts; the total weight of the second alumina micro powder, the second titanium dioxide, the boron nitride, and the silicon carbide is 100 parts.

4. The self-cleaning ceramic roller as described in claim 2, characterized in that, The roller base is a cordierite-mullite roller, and the second base material comprises the following raw materials in parts by weight: The second alumina micro powder consists of 10 to 30 parts, calcium carbonate 2 to 10 parts, boron nitride 10 to 40 parts, and cordierite 20 to 40 parts; the total weight of the second alumina micro powder, calcium carbonate, boron nitride, and cordierite is 100 parts.

5. The self-cleaning ceramic roller as described in claim 2, characterized in that, The roller base is a corundum-mullite roller, and the second base material comprises the following raw materials in parts by weight: The mixture consists of 30 to 60 parts of alumina micro powder, 2 to 10 parts of calcium carbonate, 20 to 50 parts of boron nitride, and 5 to 10 parts of titanium dioxide; the total weight of the alumina micro powder, calcium carbonate, boron nitride, and titanium dioxide is 100 parts.

6. The self-cleaning ceramic roller as described in claim 2, characterized in that, The particle size of the second alumina micro powder is 1 μm to 2 μm; and / or The particle size of the second titanium oxide is 1 μm to 4 μm; and / or The boron nitride has a particle size of 50 nm to 500 nm; and / or The silicon carbide has a particle size of 3 μm to 6 μm; and / or The cordierite has a grain size of 4μm to 10μm; and / or The calcium carbonate has a particle size ≤48μm.

7. The self-cleaning ceramic roller as described in any one of claims 1 to 6, characterized in that, The thickness of the buffer layer is ≥0.05mm.

8. The self-cleaning ceramic roller as described in any one of claims 2 to 6, characterized in that, The second dispersion comprises water and a dispersant; The dispersant is selected from one or more of sodium tripolyphosphate, sodium citrate, sodium alginate, SN-5040, and BYK-163; The weight ratio of water to dispersant is (200~500):

1.

9. The self-cleaning ceramic roller as described in claim 1, characterized in that, The weight ratio of the first base material to the first dispersion is (1~2):(8~9); The first base material comprises the following raw materials in parts by weight: The ingredients are: 20-80 parts hexagonal boron nitride, 10-30 parts lamellar corundum, and 5-20 parts alumina micro powder; the total weight of the hexagonal boron nitride, lamellar corundum, and alumina micro powder is 100 parts.

10. The self-cleaning ceramic roller as described in claim 9, characterized in that, The first dispersion comprises the following raw materials in parts by weight: 40-60 parts of polyurethane acrylate, 5-18 parts of photoinitiator, 8-20 parts of diluent, and 1-8 parts of additives; The thickness of the self-cleaning layer is ≤0.5mm.

11. The self-cleaning ceramic roller as described in claim 10, characterized in that, The photoinitiator is a mixture of photoinitiator Irgacure 2959 and photoinitiator ITX, wherein the weight ratio of photoinitiator Irgacure 2959 to photoinitiator ITX is (1~2):1; or The photoinitiator is selected as a mixture of photoinitiator Irgacure 2959 and photoinitiator EDAB, wherein the weight ratio of photoinitiator Irgacure 2959 to photoinitiator EDAB is (1~2):1; and / or The diluent is a mixture of ethoxylated trimethylolpropane triacrylate and dipentaerythritol hexaacrylate, wherein the weight ratio of ethoxylated trimethylolpropane triacrylate to dipentaerythritol hexaacrylate is (1~2):1; and / or The additive is a mixture of ethylene glycol butyl ether and isopropanol, with a weight ratio of ethylene glycol butyl ether to isopropanol of (1.2~5):

1.

12. The self-cleaning ceramic roller as described in claim 1 or 9, characterized in that, The thickness of the buffer layer is 0.1mm to 0.3mm; The thickness of the self-cleaning layer is 0.1mm to 0.3mm.

13. The self-cleaning ceramic roller as described in claim 9, characterized in that, The hexagonal boron nitride has a particle size of 20 nm to 100 nm; and / or The particle size of the platy corundum is 1μm~10μm; and / or The particle size of the first alumina micro powder is 1μm~2μm.

14. A method for preparing a self-cleaning ceramic roller, used to prepare the self-cleaning ceramic roller as described in any one of claims 1 to 13, characterized in that, include: A base coat is applied to the surface of the roller substrate and cured to form a buffer layer; A surface coating is applied to the buffer layer and cured to form a self-cleaning layer.

15. The method for preparing the self-cleaning ceramic roller as described in claim 14, characterized in that, In the step of applying a surface coating to the buffer layer and curing it to form a self-cleaning layer: The surface coating is cured by ultraviolet light. The process parameters for ultraviolet curing include: light intensity of 80 mW / cm². 2 ~120mW / cm 2 The exposure time is 10s to 30s.

16. The method for preparing the self-cleaning ceramic roller as described in claim 14, characterized in that, The step of coating the roller substrate surface with a base coat and curing it to form a buffer layer includes: The surface of the roller substrate is wetted, and then a base coat is sprayed to form a first coating. The first coating is dried to a preset moisture content to obtain the buffer layer; The preset moisture content is 0.5wt%~2wt%.

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