Protective glaze for rock plate surface and preparation method thereof

Abstract

The present invention discloses a protective glaze for rock slab surfaces and a preparation method thereof. The protective glaze comprises the following components in parts by weight: 10-25 parts potassium feldspar, 10-20 parts sodium feldspar, 10-15 parts quartz, 5-10 parts kaolin, 4-10 parts zinc oxide, 2-6 parts aluminum oxide, 2-8 parts strontium carbonate, 2-6 parts polycarboxylic acid dispersant, 0.1-0.5 parts defoamer, 0.05-0.1 parts leveling agent, and 40-55 parts solvent. The present invention also provides a preparation method thereof. Compared with the prior art, the present invention provides a polycarboxylic acid dispersant that improves the dispersibility of inorganic materials in the glaze in the solvent, thereby improving the adhesion and stability of the glaze.

Description

Technical Field

[0001] The present invention relates to the technical field of rock slab glazes, and in particular to a protective glaze for a rock slab surface and a preparation method thereof. Background Art

[0002] Slate protective glaze is a thin layer of glassy material applied to the surface of a slate. It's made using a specific formula and process, combining oxides such as silicon, aluminum, potassium, sodium, calcium, and magnesium, along with additives like flux, colorants, and opacifiers. This glaze imparts excellent wear resistance to the slate, allowing it to withstand the friction and scrapes of daily use without easily scratching. It also offers excellent acid and alkali resistance, resisting the erosion of various chemicals and preventing chemical reactions that could damage or discolor the surface. It also effectively blocks moisture from penetrating the slate, preventing swelling and deformation caused by water absorption, while also improving the slate's resistance to stains. Depending on the production process and formulation, it can achieve a variety of finishes, including high gloss, matte, and soft sheen, while maintaining a certain degree of transparency, enhancing the clarity and aesthetics of the slate's surface colors and textures.

[0003] The current types include digital glaze, dry particles and "fine carving" ink. Digital glaze is applied by inkjet printing. The glaze layer is thin and uniform, with a fineness reaching the nanometer level. It can achieve a combination of "bright and matte", and can also replace some mold effects and traditional glazes. It has a delicate texture and a matte feel. Dry particles are frits ground to a certain fineness, which become glassy after firing. Depending on the formula and process, it can present a mirror effect, a diamond-like sparkling ice crystal, or a matte or frosted texture with anti-slip and wear-resistant characteristics. "Fine carving" ink is printed onto the surface of the rock slab through an inkjet machine. After firing, it presents a concave and convex texture effect. It is suitable for the expression of modern textures such as geometry, cloth grain, and wood grain, increasing the three-dimensional sense and artistic sense of the rock slab surface.

[0004] Chinese patent publication number CN113387582A discloses a glaze designed specifically for ultra-thin ceramic rock slabs. The system covers a top glaze and a protective glaze, both of which contain ingredients such as water-soluble organic solvents, wetting and leveling agents, defoaming agents, anti-settling agents, and dispersants. Specifically, the dry materials of the top glaze are composed of albite, dolomite, high-alumina bauxite, zirconium silicate, matte frit powder, etc., while the dry materials of the protective glaze include wollastonite, albite, kaolin, calcined talc, calcined zinc oxide, calcined aluminum oxide, bright frit powder, etc., and the dispersant uses a homemade anhydrous polyacrylic acid dispersant. This glaze is suitable for high-pressure glazing technology. When applied to ultra-thin ceramic rock slabs, it can significantly reduce the defect rate after firing while maintaining the strength of the green body. At the same time, the glazing cost is low and the product quality is high.

[0005] Chinese Patent Publication No. CN113444399A discloses a ceramic digital protective glaze ink, its preparation method, and applications. The raw materials for preparing this ceramic digital protective glaze ink include a solvent, a hyperdispersant, a powder, a surfactant, and an anti-settling agent. When printed on the surface of slate tiles, this ceramic digital protective glaze ink exhibits excellent color development, a soft gloss, excellent anti-fouling and wear resistance, and a delicate feel.

[0006] Both digital glaze and ink are printed using an inkjet printer. Digital glaze creates a thin, uniform layer, achieving a combination of gloss and matte finishes. High-viscosity ink builds up, creating a concave and convex texture on the slab surface. After firing, it creates a three-dimensional feel and visual depth. However, both contain inorganic pigments, which have poor dispersibility in solvents, making them prone to agglomeration and sedimentation, affecting the final glaze's finish. Summary of the Invention

[0007] In view of the above-mentioned defects of the prior art, the technical problem to be solved by the present invention is to provide a protective glaze for the surface of a rock slab and a preparation method thereof.

[0008] To address the dispersibility issues of inorganic materials in glazes, dispersants are often added to enhance dispersion. Polycarboxylates are currently the most widely used in existing technologies. Polycarboxylates offer a strong steric hindrance, reducing particle agglomeration, providing excellent dispersion, strong stability, and resistance to pH and electrolyte interference. However, they carry the risk of decomposition at high temperatures, as glazes ultimately require high-temperature firing, and most polycarboxylates can carbonize and become ineffective at high temperatures.

[0009] Therefore, the present invention provides a polycarboxylate dispersant, which can not only better solve the dispersibility problem of inorganic pigments, but also has better high-temperature stability, and its dispersing effect will not be affected even when fired at high temperatures. Acrylic acid, functional monomers and 4-vinyl-2-pyridinecarboxylic acid are subjected to free radical polymerization under the action of an initiator to obtain a polycarboxylate dispersant. In an aqueous solution, carboxylate ions will be ionized, making the polycarboxylate itself negatively charged, thereby adsorbing on the surface of the particles. Since polycarboxylic acid has a long chain of steric hindrance and electrostatic repulsion effect, it can form "obstacles" between inorganic particles, reducing agglomeration, so it is not easy to settle in the solvent. In addition, polycarboxylates can reduce the surface tension of the glaze and water interface, making the glaze particles more easily wetted by water. This helps to disperse the glaze particles in water and also improves the stability of the glaze slurry. The polycarboxylates provided by the present invention have pyridine groups and contain lone pairs of electrons, so they can form coordination bonds with metal ions, which can further improve the adsorption of the dispersant on the surface of the glaze particles, thereby making the dispersing effect better, which is beneficial to the molding of the glaze in the later stage.

[0010] To achieve the above-mentioned purpose, the present invention provides a protective glaze for the surface of a rock slab, comprising the following components in parts by weight: 10 to 25 parts of potassium feldspar, 10 to 20 parts of sodium feldspar, 10 to 15 parts of quartz stone, 5 to 10 parts of kaolin, 4 to 10 parts of zinc oxide, 2 to 6 parts of aluminum oxide, 2 to 8 parts of strontium carbonate, 2 to 6 parts of a polycarboxylic acid dispersant, 0.1 to 0.5 parts of a defoaming agent, 0.05 to 0.1 parts of a leveling agent, and 40 to 55 parts of a solvent.

[0011] The preparation method of the polycarboxylic acid dispersant comprises the following steps:

[0012] Add acrylic acid, functional monomer and 4-vinyl-2-pyridinecarboxylic acid to N,N-dimethylformamide, stir evenly, then add benzoyl peroxide dropwise, stir at 80-90°C under an inert atmosphere for 3-4 hours, cool to room temperature and adjust the pH to obtain a polycarboxylic acid dispersant.

[0013] Furthermore, the functional monomer is one of ethyl acrylate, butyl acrylate or 3-methacryloxypropylmethyldimethoxysilane.

[0014] Furthermore, the molar ratio of acrylic acid, functional monomer, 4-vinyl-2-pyridinecarboxylic acid and benzoyl peroxide is 1:1~1.2:0.5~1.5:0.001~0.01.

[0015] Furthermore, the pH range is 6-7.

[0016] Furthermore, the defoaming agent is a silicone defoaming agent.

[0017] Furthermore, the leveling agent is a silicone leveling agent.

[0018] Furthermore, the solvent is one of ethanol, isopropanol, glycerol, butyl acetate or diethylene glycol monobutyl ether.

[0019] Preferably, the preparation method of the polycarboxylic acid dispersant comprises the following steps:

[0020] Acrylic acid, functional monomer and 4-vinyl-2-pyridinecarboxylic acid are added to N,N-dimethylformamide with a volume 4 to 8 times the total volume of the three, and after stirring evenly, benzoyl peroxide is added dropwise. The molar ratio of acrylic acid, functional monomer, 4-vinyl-2-pyridinecarboxylic acid and benzoyl peroxide is 1:1 to 1.2:0.5 to 1.5:0.001 to 0.01. Stir at 80 to 90° C. under an inert atmosphere for 3 to 4 hours, cool to room temperature, and adjust the pH to 6 to 7 to obtain the product.

[0021] A method for preparing a protective glaze on the surface of a rock plate comprises the following steps:

[0022] Mix all the components evenly according to the proportions and grind them to obtain the protective glaze on the surface of the rock slab.

[0023] Furthermore, the grinding time is 4 to 6 hours.

[0024] Furthermore, the grinding speed is 1000-1500 rpm.

[0025] Beneficial effects of the present invention:

[0026] 1. The present invention produces a polycarboxylate dispersant by free radical polymerization of acrylic acid, functional monomers, and 4-vinyl-2-pyridinecarboxylic acid in the presence of an initiator. This polycarboxylate creates a barrier between inorganic particles through steric hindrance and electrostatic repulsion, reducing aggregation and thus preventing sedimentation in solvents. Furthermore, the polycarboxylate can reduce the surface tension at the glaze-water interface, making the glaze particles more easily wetted by water. This facilitates the dispersion of the glaze particles in water and improves the stability of the glaze slurry.

[0027] 2. Compared with the prior art, the polycarboxylate provided by the present invention has a pyridine group and contains lone pairs of electrons, so it can form a coordination bond with the metal ions, which can further improve the adsorption of the dispersant on the surface of the glaze particles, thereby achieving a better dispersion effect, which is beneficial to the later glaze molding.

[0028] 3. Compared with the prior art, the polycarboxylate dispersant provided by the present invention can not only better solve the dispersibility problem of inorganic pigments, but also has better high-temperature stability, and its dispersion effect will not be affected even when sintered at high temperatures. DETAILED DESCRIPTION

[0029] Defoamer BYK-052, from BYK Chemical.

[0030] Leveling agent BYK-306 comes from BYK Chemical.

[0031] Polyacrylamide, model: AN 923 PGO, sourced from Eisen, France.

[0032] Example 1

[0033] A method for preparing a protective glaze on the surface of a rock plate comprises the following steps:

[0034] In parts by weight, 20 parts of potassium feldspar, 15 parts of sodium feldspar, 12 parts of quartz stone, 8 parts of kaolin, 6 parts of zinc oxide, 4 parts of aluminum oxide, 3 parts of strontium carbonate, 4 parts of polycarboxylic acid dispersant, 0.4 parts of BYK-052, 0.06 parts of BYK-306 and 50 parts of isopropyl alcohol are mixed evenly and ground at 1200 rpm for 4 hours to obtain a protective glaze on the surface of the rock slab.

[0035] The preparation method of the polycarboxylic acid dispersant comprises the following steps:

[0036] Acrylic acid, ethyl acrylate, and 4-vinyl-2-pyridinecarboxylic acid are added to N,N-dimethylformamide (5 times the total volume of the three), stirred evenly, and then benzoyl peroxide is added dropwise. The molar ratio of acrylic acid, ethyl acrylate, 4-vinyl-2-pyridinecarboxylic acid, and benzoyl peroxide is 1:1.1:1:0.005. Stir at 85°C under an inert atmosphere for 4 hours, cool to room temperature, and adjust the pH to 7 to obtain the product.

[0037] Example 2

[0038] A method for preparing a protective glaze on the surface of a rock plate comprises the following steps:

[0039] In parts by weight, 20 parts of potassium feldspar, 15 parts of sodium feldspar, 12 parts of quartz stone, 8 parts of kaolin, 6 parts of zinc oxide, 4 parts of aluminum oxide, 3 parts of strontium carbonate, 4 parts of polycarboxylic acid dispersant, 0.4 parts of BYK-052, 0.06 parts of BYK-306 and 50 parts of isopropyl alcohol are mixed evenly and then ground. The mixture is ground at 1200 rpm for 4 hours to obtain a protective glaze on the surface of the rock slab.

[0040] The preparation method of the polycarboxylic acid dispersant comprises the following steps:

[0041] Acrylic acid, butyl acrylate, and 4-vinyl-2-pyridinecarboxylic acid are added to N,N-dimethylformamide (5 times the total volume of the three), stirred evenly, and then benzoyl peroxide is added dropwise. The molar ratio of acrylic acid, butyl acrylate, 4-vinyl-2-pyridinecarboxylic acid, and benzoyl peroxide is 1:1.1:1:0.005. Stir at 85°C under an inert atmosphere for 4 hours, cool to room temperature, and adjust the pH to 7 to obtain the product.

[0042] Example 3

[0043] A method for preparing a protective glaze on the surface of a rock plate comprises the following steps:

[0044] In parts by weight, 20 parts of potassium feldspar, 15 parts of sodium feldspar, 12 parts of quartz stone, 8 parts of kaolin, 6 parts of zinc oxide, 4 parts of aluminum oxide, 3 parts of strontium carbonate, 4 parts of polycarboxylic acid dispersant, 0.4 parts of BYK-052, 0.06 parts of BYK-306 and 50 parts of isopropyl alcohol are mixed evenly and ground at 1200 rpm for 4 hours to obtain a protective glaze on the surface of the rock slab.

[0045] The preparation method of the polycarboxylic acid dispersant comprises the following steps:

[0046] Acrylic acid, 3-methacryloxypropylmethyldimethoxysilane, and 4-vinyl-2-pyridinecarboxylic acid are added to N,N-dimethylformamide (5 times the total volume of the three), stirred evenly, and then benzoyl peroxide is added dropwise; the molar ratio of acrylic acid, 3-methacryloxypropylmethyldimethoxysilane, 4-vinyl-2-pyridinecarboxylic acid, and benzoyl peroxide is 1:1.1:1:0.005, stirred at 85°C under an inert atmosphere for 4 hours, cooled to room temperature, and then the pH is adjusted to 7 to obtain the product.

[0047] Comparative Example 1

[0048] A method for preparing a protective glaze on the surface of a rock plate comprises the following steps:

[0049] In parts by weight, 20 parts of potassium feldspar, 15 parts of sodium feldspar, 12 parts of quartz stone, 8 parts of kaolin, 6 parts of zinc oxide, 4 parts of aluminum oxide, 3 parts of strontium carbonate, 4 parts of polyacrylamide, 0.4 parts of BYK-052, 0.06 parts of BYK-306 and 50 parts of isopropyl alcohol are mixed evenly and ground at 1200 rpm for 4 hours to obtain a protective glaze on the surface of the rock slab.

[0050] Comparative Example 2

[0051] A method for preparing a protective glaze on the surface of a rock plate comprises the following steps:

[0052] In parts by weight, 20 parts of potassium feldspar, 15 parts of sodium feldspar, 12 parts of quartz stone, 8 parts of kaolin, 6 parts of zinc oxide, 4 parts of aluminum oxide, 3 parts of strontium carbonate, 4 parts of polycarboxylic acid dispersant, 0.4 parts of BYK-052, 0.06 parts of BYK-306 and 50 parts of isopropyl alcohol are mixed evenly and ground at 1200 rpm for 4 hours to obtain a protective glaze on the surface of the rock slab.

[0053] The preparation method of the polycarboxylic acid dispersant comprises the following steps:

[0054] Acrylic acid, 3-methacryloxypropylmethyldimethoxysilane and 5-hexenoic acid are added to N,N-dimethylformamide with a volume 5 times the total volume of the three, and after stirring evenly, benzoyl peroxide is added dropwise. The molar ratio of acrylic acid, 3-methacryloxypropylmethyldimethoxysilane, 5-hexenoic acid and benzoyl peroxide is 1:1.1:1:0.005. Stir at 85°C under an inert atmosphere for 4 hours, cool to room temperature, and adjust the pH to 7 to obtain the product.

[0055] Test Example 1

[0056] The glazes of the examples and comparative examples were tested for sedimentation rate. The glazes were placed in bottles and sealed at 70°C for 7 days. The samples were then inverted for 5 minutes to allow any glaze clinging to the bottle walls to drip. The remaining glaze in the bottle was weighed and recorded. The ratio of the remaining glaze weight to the total glaze weight was calculated to determine the sedimentation rate. The results are shown in Table 1.

[0057] Table 1

[0058]

[0059] The sedimentation rate directly reflects the stability of the glaze in suspension. A low sedimentation rate indicates that the glaze particles are evenly suspended in the medium and are not prone to sinking, indicating good suspension stability. A high sedimentation rate indicates poor suspension stability, with particles easily settling under gravity. This can cause stratification of the glaze slurry, affecting the subsequent glazing process and glaze surface quality. When the glaze has good dispersibility, the particles are evenly distributed in the medium. The interaction between them prevents them from agglomerating and settling, resulting in a low sedimentation rate.

[0060] As can be seen from Table 1, compared with Comparative Example 1, the glaze prepared in Example has a lower sedimentation rate. This may be due to the relatively low charge density of polyacrylamide and the weak electrostatic repulsion. In the glaze system, for some particles with higher charges, polyacrylamide may not provide sufficient electrostatic repulsion to achieve good dispersion, and the dispersion effect may be limited. Compared with Comparative Example 2, Example 2 uses 4-vinyl-2-pyridinecarboxylic acid to participate in the preparation of polycarboxylate. Pyridine contains lone pairs of electrons and can therefore form coordination bonds with metal ions. This can further enhance the adsorption of the dispersant on the surface of the glaze particles, thereby achieving a better dispersion effect.

[0061] The polycarboxylic acid dispersant in the embodiment will ionize carboxylate ions in aqueous solution, making itself negatively charged, thereby adsorbing on the surface of the particles. Since polycarboxylic acid has long-chain steric hindrance and electrostatic repulsion effect, it can form "obstructions" between inorganic particles, reducing agglomeration, and is therefore not easy to settle in the solvent. In addition, polycarboxylates can reduce the surface tension of the glaze and water interface, making the glaze particles more easily wetted by water. This helps to disperse the glaze particles in water and also improves the stability of the glaze slurry. In Example 3, 3-methacryloxypropylmethyldimethoxysilane is used as a functional monomer. The addition of 3-methacryloxypropylmethyldimethoxysilane can better enhance the steric hindrance effect of the polycarboxylic acid dispersant, thereby enhancing the dispersion effect. Therefore, the glaze sedimentation rate of Example 3 is the lowest.

[0062] Test Example 2

[0063] The glazes prepared in the embodiment and the control example were glazed on the same rock slab body by inkjet process, with a spraying amount of 50g / m 2 After firing at 1200℃, the obtained glaze surface was subjected to a wear resistance test. The test method refers to GB / T 3810.7-2016 Ceramic Tile Test Methods Part 7: Determination of Surface Abrasion Resistance of Glazed Tiles. The test results are shown in Table 2.

[0064] Table 2

[0065]

[0066] As can be seen from Table 1, the glaze prepared in Example 3 finally has better glaze wear resistance, which may be because the dispersant can make the glaze particles evenly dispersed in the glaze slurry, avoiding agglomeration. During the firing process, the evenly dispersed particles will melt and crystallize more evenly, and the formed glaze layer will have a uniform microstructure, dense texture, and no obvious defects, thereby improving the wear resistance of the glaze layer. The polycarboxylate dispersant can evenly disperse the glaze particles through electrostatic repulsion and steric hindrance, and the glaze layer after firing has a uniform structure and good wear resistance. In Example 3, 3-methacryloxypropylmethyldimethoxysilane is used as a functional monomer, which can effectively improve the stability of the dispersant at high temperatures, thereby ensuring the effectiveness of the dispersant.

[0067] Dispersants evenly disperse glaze particles, helping the glaze slurry spread and adhere evenly to the surface of the green body, forming a good bond with the green body during firing. This excellent bond prevents the glaze layer from detaching from the green body surface when subjected to external friction, thereby improving the glaze's overall wear resistance. Dispersants also adjust the glaze's rheological properties, ensuring optimal fluidity at high temperatures. During firing, a glaze with good fluidity can better fill in the subtle irregularities on the green body surface, forming a smooth, even glaze layer. A smooth glaze surface reduces friction, minimizes wear, and improves wear resistance.

[0068] However, Examples 1-2 and the control example may have poor stability at high temperatures, which affects the dispersion effect of the glaze, further affecting the rheological properties of the glaze and the bonding with the body, so the wear resistance is not as good as that of Example 3.

[0069] The above describes in detail the preferred embodiments of the present invention. It should be understood that those skilled in the art can make numerous modifications and variations based on the concepts of the present invention without inventive effort. Therefore, any technical solutions that can be derived by those skilled in the art through logical analysis, reasoning, or limited experimentation based on the concepts of the present invention and the prior art should be within the scope of protection defined by the claims.

Claims

1. A protective glaze for the surface of a rock plate, characterized in that: The invention comprises the following components in parts by weight: 10-25 parts of potassium feldspar, 10-20 parts of sodium feldspar, 10-15 parts of quartz stone, 5-10 parts of kaolin, 4-10 parts of zinc oxide, 2-6 parts of aluminum oxide, 2-8 parts of strontium carbonate, 2-6 parts of polycarboxylic acid dispersant, 0.1-0.5 parts of defoaming agent, 0.05-0.1 parts of leveling agent and 40-55 parts of solvent; The preparation method of the polycarboxylic acid dispersant comprises the following steps: Acrylic acid, 3-methacryloyloxypropylmethyldimethoxysilane and 4-vinyl-2-pyridinecarboxylic acid are added to N,N-dimethylformamide, stirred evenly, and then benzoyl peroxide is added dropwise. The mixture is stirred at 80-90°C under an inert atmosphere for 3-4 hours. After cooling to room temperature, the pH is adjusted to obtain a polycarboxylic acid dispersant.

2. The protective glaze for the surface of the rock plate according to claim 1, characterized in that: The molar ratio of the acrylic acid, the functional monomer, the 4-vinyl-2-pyridinecarboxylic acid and the benzoyl peroxide is 1:1-1.2:0.5-1.5:0.001-0.

01.

3. The protective glaze for the surface of the rock plate according to claim 1, characterized in that: The pH range is 6-7.

4. The protective glaze for the surface of a rock plate according to claim 1, characterized in that: The defoaming agent is an organosilicon defoaming agent.

5. The protective glaze for the surface of a rock plate according to claim 1, characterized in that: The leveling agent is an organic silicon leveling agent.

6. The protective glaze for the surface of a rock plate according to claim 1, characterized in that: The solvent is one of ethanol, isopropanol, glycerol, butyl acetate or diethylene glycol monobutyl ether.

7. The method for preparing the protective glaze for the surface of a rock plate according to any one of claims 1 to 6, characterized in that: The following steps are involved: Mix all the components evenly according to the proportions and grind them to obtain the protective glaze on the surface of the rock slab.

8. The method for preparing the protective glaze for the surface of the rock plate according to claim 7, characterized in that: The grinding time is 4 to 6 hours.

9. The method for preparing the protective glaze for the surface of the rock plate according to claim 7, characterized in that: The grinding speed is 1000-1500 rpm.

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