Silver ion synergistic antibacterial ceramic glaze and preparation method thereof

Abstract

This invention relates to the field of glaze technology and discloses a silver ion-enhanced antibacterial ceramic glaze and its preparation method. The ceramic glaze is mainly composed of the following raw materials in parts by weight: 20-30 parts feldspar powder, 10-20 parts bauxite, 1-5 parts zinc oxide, 10-20 parts kaolin, 2-4 parts borax, 1-2 parts rare earth elements, 1-5 parts polysiliconazine, 1-5 parts organic-hybrid aluminum dihydrogen phosphate, 0.2-0.5 parts sodium tripolyphosphate, and 0.1-0.3 parts carboxymethyl cellulose. This invention prepares a polysiliconazine and an organic-hybrid aluminum dihydrogen phosphate, which undergo an addition reaction under the action of a high-temperature catalyst. This increases the crosslinking density of the glaze layer, thereby improving its compactness. The higher crosslinking density enhances the long-lasting antibacterial properties and toughness.

Description

Technical Field

[0001] This invention relates to the field of glaze technology, specifically to a silver ion-enhanced antibacterial ceramic glaze and its preparation method. Background Technology

[0002] Antibacterial ceramics, as a type of functional ceramic material with hygienic protection function, have broad application prospects in medical, home, and public facilities fields. Their core antibacterial mechanism usually relies on introducing active ingredients with antibacterial function into ceramic glaze, such as metal ions such as silver, copper, and zinc. Among them, silver ions have become one of the most commonly used antibacterial agents due to their broad-spectrum, high-efficiency antibacterial properties and relatively low biotoxicity.

[0003] Traditional silver ion antibacterial ceramic glazes mainly introduce silver-containing compounds (such as silver nitrate, silver-loaded zirconium phosphate, etc.) into the traditional silicate glaze system through physical doping or simple adsorption. However, during the high-temperature firing process of ceramics, silver ions are prone to reduction, aggregation or volatilization, resulting in a large loss of effective antibacterial components. In the later use process, especially after long-term wear or water rinsing, silver ions on the glaze surface are prone to premature precipitation and loss, making it difficult to achieve long-term and stable antibacterial effects.

[0004] Traditional glazes are essentially brittle glass phases. Their hard and brittle properties make ceramic products prone to micro-cracks or even peeling when subjected to impact or rapid temperature changes. These micro-cracks not only affect the appearance and lifespan of the products, but may also become hiding places for bacterial growth and accelerate the unintended release of internal antibacterial components.

[0005] Based on this, the present invention proposes a silver ion-enhanced antibacterial ceramic glaze and its preparation method to solve the above problems. Summary of the Invention

[0006] (a) Technical problems to be solved

[0007] To address the shortcomings of existing technologies, this invention provides a silver ion-enhanced antibacterial ceramic glaze and its preparation method. The prepared glaze exhibits excellent adhesion, long-lasting antibacterial properties, and mechanical properties.

[0008] (II) Technical Solution

[0009] A silver ion-enhanced antibacterial ceramic glaze, wherein the ceramic glaze is mainly composed of the following raw materials in parts by weight:

[0010] 20-30 parts by weight feldspar powder, 10-20 parts by weight bauxite, 1-5 parts by weight zinc oxide, 10-20 parts by weight kaolin, 2-4 parts by weight borax, 1-2 parts by weight rare earth elements, 1-5 parts by weight polysiliconazine, 1-5 parts by weight organic-hybrid aluminum dihydrogen phosphate, 0.2-0.5 parts by weight sodium tripolyphosphate, 0.1-0.3 parts by weight carboxymethyl cellulose;

[0011] The preparation method of the silver ion-enhanced antibacterial ceramic glaze includes the following steps:

[0012] Feldspar powder, bauxite, zinc oxide, kaolin, borax, rare earth elements, polysiliconazine, organic hybrid aluminum dihydrogen phosphate, sodium tripolyphosphate, carboxymethyl cellulose, and cassiterite catalyst were added to a ball mill jar. Zirconia balls were used as the milling medium and deionized water was used as the solvent. The mixture was milled for 24 hours at a ratio of material:ball:water = 1:2:1. The mixture was then passed through a 250-mesh sieve to obtain a high-performance ceramic glaze for antibacterial daily-use porcelain.

[0013] The sodium tripolyphosphate used in this invention is a highly efficient dispersant that can be adsorbed onto the surface of glaze particles, increasing the electrostatic repulsion between particles, preventing particle agglomeration, thereby effectively reducing the viscosity of the glaze slurry and ensuring the stability of the glaze slurry during long-term storage.

[0014] Preferably, the rare earth element is one of europium, lanthanum, and cerium; wherein europium ions combine with negatively charged groups on the bacterial cell membrane, changing the membrane permeability, causing the contents to flow out and killing the bacteria.

[0015] Preferably, the preparation method of the polysilicon silazane includes the following steps:

[0016] Polysilazane was added to tetrahydrofuran solvent and stirred to disperse it. Then silver nitrate was added and the mixture was magnetically stirred for 10-12 hours. After the reaction was completed, the mixture was allowed to stand, filtered, and distilled to obtain polysilazane. Polysilazane contains -NH-, which can coordinate with silver ions in silver nitrate to form coordinate bonds. This tightly confines the silver ions in the physical network structure of polysilazane, reducing the precipitation effect of silver ions and improving the long-lasting antibacterial properties.

[0017] Preferably, the amount of silver nitrate used is 1-5% of the mass of the polysilazane.

[0018] Preferably, the method for preparing the organic-hybrid aluminum dihydrogen phosphate includes the following steps:

[0019] Aluminum dihydrogen phosphate was added to a beaker, followed by the addition of triethoxysilane. The mixture was stirred and mixed for 1-2 hours. After the reaction was complete, the mixture was allowed to stand and dried to obtain organic-hybrid aluminum dihydrogen phosphate. During this process, aluminum dihydrogen phosphate was acidic. Triethoxysilane hydrolyzed under acidic conditions to produce silanol groups, which then condensed with aluminum dihydrogen phosphate to form PO-Si bonds. This process grafted organosiloxane groups onto the surface of aluminum dihydrogen phosphate, achieving an organic-inorganic hybrid process. An organosilane film was formed on the surface of aluminum dihydrogen phosphate, and this film contained a large number of silane-hydrogen structures to facilitate subsequent reactions.

[0020] Preferably, the amount of triethoxysilane used is 5-10% of the mass of aluminum dihydrogen phosphate.

[0021] A method for glazing using the aforementioned silver ion-enhanced antibacterial ceramic glaze: The silver ion-enhanced antibacterial ceramic glaze is uniformly coated onto the surface of a cleaned blank. The blank is then dried in an oven at 50-60°C for 3-4 hours. It is then placed in a high-temperature electric furnace for firing, with the heating rate controlled at 10°C / min. The temperature is raised to 300-500°C and held for 3-4 hours. The temperature is then raised to 1000-1200°C for firing. Finally, the blank is cooled to 300-400°C at 5°C / min and then cooled to room temperature with the furnace to obtain a fired sample.

[0022] Under the action of a high-temperature catalyst, a large number of silicon-hydrogen structures on the surface of aluminum dihydrogen phosphate undergo an addition reaction with the alkenyl groups contained in polysiliconazine to form a cross-linked network structure. The increased degree of cross-linking of the ceramic sample not only further enhances the antibacterial durability of antibacterial components such as silver and rare earth elements, but also brings a denser ceramic structure to the denser cross-linked structure, thereby improving the toughness of the sample.

[0023] (iii) Beneficial technical effects

[0024] This invention grafts siloxane groups onto the surface of aluminum dihydrogen phosphate, reducing the agglomeration degree of the aluminum dihydrogen phosphate surface and forming a silane film on the aluminum dihydrogen phosphate surface. The silane provides chemical bonding and steric hindrance. Then, by using sodium tripolyphosphate, the particles are stabilized by electrostatic repulsion. The two work together to disperse the aluminum dihydrogen phosphate, avoiding agglomeration that causes brittleness of the glaze layer and improving the adhesion performance between the glaze and the body.

[0025] This invention employs a two-stage heating process. The first stage of heating serves two purposes: firstly, to slowly and thoroughly remove residual water and other small molecules from the body and glaze. Rapid heating leads to a sudden increase in internal pressure, potentially causing cracking or blistering. Holding the temperature ensures sufficient heat penetration, allowing water and small organic molecules to evaporate smoothly, preventing defects at later high temperatures. Secondly, during sintering, when the temperature reaches the point where the polymer begins its cross-linking reaction, sufficient holding time allows the polymer to fully cross-link and solidify, forming a three-dimensional network structure. This prevents excessive decomposition of the polymer due to incomplete cross-linking during heating, resulting in low ceramicization. In the second stage of heating, the polymer's organic network transforms into inorganic ceramic. Feldspar and borax in the glaze fully melt at this temperature, forming a stable body-glaze interlayer on the body surface, enhancing ceramic strength. Directly and rapidly heating from a low temperature to the final high temperature could prematurely seal the glaze surface, hindering internal gas escape and leading to defects such as pinholes, bubbles, and cracks. Attached Figure Description

[0026] Figure 1 This is a low-magnification scanning electron microscope image of Example 2;

[0027] Figure 2 This is a low-magnification scanning electron microscope image of Comparative Example 3. Detailed Implementation

[0028] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments are merely illustrative of the invention and should not be considered as specific limitations thereof. Unless otherwise defined, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used in this specification is for the purpose of describing specific embodiments only and is not intended to limit the invention.

[0029] Polysilazane was purchased from the Institute of Chemistry, Chinese Academy of Sciences. Its structural formula is as follows:

[0030] ;

[0031] All other raw materials are commercially available products.

[0032] Example 1

[0033] (1) Add 20g of polysilazane to tetrahydrofuran solvent, stir and disperse, then add 0.2g of silver nitrate, stir magnetically for 12h, after the reaction is completed, let stand, filter, and distill to obtain polysilazane;

[0034] (2) Add 20g of aluminum dihydrogen phosphate to a beaker, add 1g of triethoxysilane, stir and mix for 2h, after the reaction is complete, let stand and dry to obtain organic hybrid aluminum dihydrogen phosphate;

[0035] (3) By weight, 20 parts feldspar powder, 20 parts bauxite, 1 part zinc oxide, 20 parts kaolin, 4 parts borax, 2 parts europium, 1 part polysiliconazine, 1 part organic hybrid aluminum dihydrogen phosphate, 0.3 parts sodium tripolyphosphate, 0.1 parts carboxymethyl cellulose, and 2% caster catalyst are added to a ball mill jar. Zirconia balls are used as the ball milling medium and deionized water is used as the solvent. The mixture is ball milled for 24 hours at a ratio of material:ball:water = 1:2:1. The mixture is then passed through a 250-mesh sieve to obtain a high-performance ceramic glaze for antibacterial daily-use porcelain.

[0036] (4) The silver ion enhanced antibacterial ceramic glaze is evenly coated on the surface of the cleaned blank. It is dried in an oven at 55°C for 4 hours, and then placed in a high-temperature electric furnace for firing. The heating rate is controlled at 10°C / min. The temperature is raised to 300°C and held for 3 hours. Then the temperature is raised to 1000°C and fired for 5 hours. Finally, it is cooled to 300°C at 5°C / min and cooled to room temperature with the furnace to obtain the fired sample.

[0037] Example 2

[0038] (1) Add 20g of polysilazane to tetrahydrofuran solvent, stir and disperse, then add 0.5g of silver nitrate, stir magnetically for 11h, after the reaction is completed, let stand, filter, and distill to obtain polysilazane;

[0039] (2) Add 20g of aluminum dihydrogen phosphate to a beaker, add 1.5g of triethoxysilane, stir and mix for 2h, after the reaction is complete, let stand and dry to obtain organic hybrid aluminum dihydrogen phosphate;

[0040] (3) By weight, 25 parts feldspar powder, 15 parts bauxite, 3 parts zinc oxide, 10 parts kaolin, 2 parts borax, 1 part europium, 3 parts polysiliconazine, 3 parts organic hybrid aluminum dihydrogen phosphate, 0.2 parts sodium tripolyphosphate, 0.2 parts carboxymethyl cellulose, and 2% caster catalyst are added to a ball mill jar. Zirconia balls are used as the ball milling medium and deionized water is used as the solvent. The mixture is ball milled for 24 hours at a ratio of material:ball:water = 1:2:1. The mixture is then passed through a 250-mesh sieve to obtain a high-performance ceramic glaze for antibacterial daily-use porcelain.

[0041] (4) The silver ion enhanced antibacterial ceramic glaze is evenly coated on the surface of the cleaned blank. It is dried in an oven at 60°C for 3 hours, and then placed in a high-temperature electric furnace for firing. The heating rate is controlled at 10°C / min. The temperature is raised to 300°C and held for 4 hours. The temperature is then raised to 1000°C and fired for 5 hours. Finally, it is cooled to 350°C at 5°C / min and cooled to room temperature with the furnace to obtain the fired sample.

[0042] Example 3

[0043] (1) Add 20g of polysilazane to tetrahydrofuran solvent, stir and disperse, then add 1g of silver nitrate, stir magnetically for 10h, after the reaction is completed, let stand, filter, and distill to obtain polysilazane.

[0044] (2) Add 20g of aluminum dihydrogen phosphate to a beaker, add 2g of triethoxysilane, stir and mix for 1h, after the reaction is complete, let stand and dry to obtain organic hybrid aluminum dihydrogen phosphate;

[0045] (3) By weight, 30 parts feldspar powder, 10 parts bauxite, 5 parts zinc oxide, 15 parts kaolin, 3 parts borax, 2 parts europium, 5 parts polysiliconazine, 5 parts organic hybrid aluminum dihydrogen phosphate, 0.5 parts sodium tripolyphosphate, 0.3 parts carboxymethyl cellulose, and 2% caster catalyst are added to a ball mill jar. Zirconia balls are used as the ball milling medium and deionized water is used as the solvent. The mixture is ball milled for 24 hours at a ratio of material:ball:water = 1:2:1. The mixture is then passed through a 250-mesh sieve to obtain a high-performance ceramic glaze for antibacterial daily-use porcelain.

[0046] (4) The silver ion enhanced antibacterial ceramic glaze is evenly coated on the surface of the cleaned blank. It is dried in an oven at 50°C for 4 hours, and then placed in a high-temperature electric furnace for firing. The heating rate is controlled at 10°C / min. The temperature is raised to 300°C and held for 4 hours. The temperature is then raised to 1100°C and fired for 5 hours. Finally, it is cooled to 400°C at 5°C / min and cooled to room temperature with the furnace to obtain the fired sample.

[0047] Comparative Example 1

[0048] The difference between this comparative example and Example 1 is that polymethylsilane is used instead of polysilazane in step (1), while the remaining steps are the same as in Example 1.

[0049] Comparative Example 2

[0050] The difference between this comparative example and Example 1 is that aluminum dihydrogen phosphate is replaced by organic hybrid aluminum dihydrogen phosphate in step (3), while the remaining steps are the same as in Example 1.

[0051] Comparative Example 3

[0052] The difference between this comparative example and Example 1 is as follows:

[0053] The silver ion-enhanced antibacterial ceramic glaze was evenly coated on the cleaned surface of the blank. It was then dried in an oven at 55°C for 4 hours, and then placed in a high-temperature electric furnace for firing. The heating rate was controlled at 10°C / min, and the temperature was raised to 1000°C for 5 hours. Finally, it was cooled to 300°C at 5°C / min and then cooled to room temperature with the furnace to obtain the fired sample.

[0054] According to GB / T3810.7-2016, the wear resistance was tested;

[0055] Antibacterial tests were conducted in accordance with the JC / T897-2014 standard "Antibacterial Properties of Antibacterial Ceramic Products". The test strain was Escherichia coli. The sample was then rinsed in deionized water for one week to test the antibacterial rate.

[0056] Table 1:

[0057]

[0058] As shown in the table, the ceramic samples prepared by this invention have good wear resistance. The antibacterial test results show that the embodiments with dense cross-linked network structures have higher antibacterial durability. This is because the cross-linked network structure can firmly anchor antibacterial ions (silver ions, rare earth elements) in the cross-linked network structure of the glaze. During the ceramicization process, the antibacterial ions can also be encapsulated, reducing the high-temperature volatilization and reduction of antibacterial ions, improving the high-temperature stability of antibacterial ions and their retention rate in the glaze layer, thereby improving the antibacterial durability.

[0059] Observe whether the glaze sample is smooth, or whether there are cracks or holes.

[0060] The fracture toughness of the specimen was tested using a universal testing machine and the single-sided notched beam method. The specimen size was 25mm × 5mm × 2.5mm.

[0061] Table 2:

[0062]

[0063] As shown in Table 2, the ceramic glaze prepared by this invention has a relatively complete ceramic structure. Comparative Example 1 uses polymethylsilane instead of polysilazane, which does not contain an alkenyl structure. Comparative Example 2 uses aluminum dihydrogen phosphate instead of organic-hybrid aluminum dihydrogen phosphate, which does not contain a silane-hydrogen structure. Neither can form a dense cross-linked network structure; therefore, the degree of ceramicization is low, the ceramic structure is incomplete, and the surface is rough. Comparative Example 3 involves directly heating the temperature to 1000℃ for firing, without a heat-holding reaction stage. Therefore, moisture and small organic molecules cannot volatilize smoothly, the polymer reaction degree is low, defects occur at high temperatures, and the integrity of the ceramic structure is poor.

[0064] The greater the fracture toughness, the less brittle. The fracture toughness test results show that the ceramic sample prepared in this invention has good toughness. In Comparative Example 1, polymethylsilane was used instead of polysilazane, which does not contain alkenyl structures, thus failing to form a dense cross-linked network structure. During the ceramization process, a continuous homogeneous structure could not be formed. A homogeneous structure can withstand some loads and prevent dislocation within the glaze layer, thus strengthening the load-bearing capacity of the glaze layer and improving mechanical properties such as toughness. Therefore, Comparative Example 1 has lower toughness. In Comparative Example 2, aluminum dihydrogen phosphate was used instead of organic hybrid aluminum dihydrogen phosphate, which does not contain silane structures. On the one hand, it cannot form a cross-linked network structure; on the other hand, aluminum dihydrogen phosphate is brittle after sintering, affecting the toughness of the ceramic, thus resulting in poor fracture toughness. Comparative Example 3 lacks a heat-holding stage, has a low degree of polymer reaction, more small molecule structures, and a low degree of ceramization, thus resulting in lower toughness.

[0065] Depend on Figure 1 , Figure 2 It can be seen that the ceramic glaze prepared by this invention can form a dense and continuous ceramic material after being kept at a constant temperature and then sintered at a high temperature.

[0066] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A silver ion synergistic antibacterial ceramic glaze, characterized in that, The ceramic glaze is mainly composed of the following raw materials in parts by weight: 20-30 parts by weight feldspar powder, 10-20 parts by weight bauxite, 1-5 parts by weight zinc oxide, 10-20 parts by weight kaolin, 2-4 parts by weight borax, 1-2 parts by weight rare earth elements, 1-5 parts by weight polysiliconazine, 1-5 parts by weight organic-hybrid aluminum dihydrogen phosphate, 0.2-0.5 parts by weight sodium tripolyphosphate, 0.1-0.3 parts by weight carboxymethyl cellulose; The preparation method of the silver ion-enhanced antibacterial ceramic glaze includes the following steps: Feldspar powder, bauxite, zinc oxide, kaolin, borax, rare earth elements, polysiliconazine, organic hybrid aluminum dihydrogen phosphate, sodium tripolyphosphate, carboxymethyl cellulose, and cassiterite catalyst were added to a ball mill jar. Zirconia balls were used as the milling medium and deionized water was used as the solvent. The mixture was milled for 24 hours at a ratio of material:ball:water = 1:2:

1. The mixture was then passed through a 250-mesh sieve to obtain a high-performance ceramic glaze for antibacterial daily-use porcelain.

2. The silver ion synergistic antibacterial ceramic glaze according to claim 1, characterized in that, The rare earth element is one of europium, lanthanum, and cerium.

3. The silver ion synergistic antibacterial ceramic glaze according to claim 1, characterized in that, The preparation method of the polysilazane includes the following steps: Polysilazane was added to tetrahydrofuran solvent, stirred and dispersed, and then silver nitrate was added. The mixture was magnetically stirred and reacted for 10-12 hours. After the reaction was completed, the mixture was allowed to stand, filtered, and distilled to obtain polysilazane.

4. The silver ion synergistic antibacterial ceramic glaze according to claim 3, characterized in that, The amount of silver nitrate used is 1-5% of the mass of the polysilazane.

5. The silver ion synergistic antibacterial ceramic glaze of claim 1, wherein, The method for preparing the organic-hybrid aluminum dihydrogen phosphate includes the following steps: Aluminum dihydrogen phosphate was added to a beaker, and triethoxysilane was added to it. The mixture was stirred for 1-2 hours. After the reaction was completed, the mixture was allowed to stand and dried to obtain organic-hybrid aluminum dihydrogen phosphate.

6. The silver ion synergistic antibacterial ceramic glaze according to claim 5, characterized in that, The amount of triethoxysilane used is 5-10% of the mass of aluminum dihydrogen phosphate.

7. A method of glazing using the silver ion synergistic antibacterial ceramic glaze according to any one of claims 1 to 6, characterized in that: The silver ion-enhanced antibacterial ceramic glaze was evenly coated on the cleaned surface of the blank. It was then dried in an oven at 50-60℃ for 3-4 hours. After that, it was placed in a high-temperature electric furnace for firing, with the heating rate controlled at 10℃ / min. The temperature was raised to 300-500℃ and held for 3-4 hours. Then, the temperature was raised to 1000-1200℃ for firing. Finally, it was cooled to 300-400℃ at 5℃ / min and cooled to room temperature with the furnace to obtain the fired sample.

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