Ceramic-based antibacterial sustained-release ball and preparation method thereof

Abstract

The invention provides a ceramic-based antibacterial sustained-release ball and a preparation method thereof. The antibacterial sustained-release ball is formed by sintering the following raw materials in percentage by mass: 78-85.5% of a ceramic matrix, 10-15% of a pore structure regulating agent, 1.5-3.6% of an antibacterial active component and 2-3% of an auxiliary functional component, the pore structure regulating agent is used for forming a multi-stage pore channel structure in the sintering process and controlling the release rate of the antibacterial active component. A stable three-dimensional network skeleton is constructed through a ceramic matrix, segmented sintering is adopted in the sintering process, a multi-stage pore channel structure is formed firstly, then sintering and curing are performed to form a stable porous ceramic skeleton, and antibacterial components such as silver-loaded zeolite are firmly immobilized in the skeleton and in pore channels. In a water soaking environment, silver ions are slowly and controllably released through the micro-pores, so that short-term failure caused by explosive release is avoided, and a continuous antibacterial effect as long as several months can be realized.

Description

Technical Field

[0001] This invention belongs to the field of antibacterial materials technology, specifically relating to a ceramic-based antibacterial slow-release ball and its preparation method, which is particularly suitable for the clean water tank and wastewater tank of intelligent cleaning equipment such as sweeping robots and mopping robots. Background Technology

[0002] With the increasing popularity of smart homes, robotic vacuum cleaners and mops have become indispensable cleaning tools for modern families. These devices are typically equipped with clean water tanks and waste water tanks. The inside of the water tanks is a constantly damp environment, which easily breeds bacteria, mold, and other microorganisms. The proliferation of microorganisms not only produces odors and affects the home environment, but may also contaminate the water tanks and even re-contaminate the cleaned floors, posing a potential threat to the user's health.

[0003] Currently, common solutions include adding liquid antibacterial agents or using ultraviolet (UV) sterilization modules. However, liquid antibacterial agents are flushed out with each water change, failing to provide long-lasting antibacterial protection and requiring frequent refills, resulting in a poor user experience. UV sterilization modules, on the other hand, suffer from high costs, high energy consumption, and limited effectiveness in sterilizing hard-to-reach areas of the water tank.

[0004] Existing research has focused on fabricating inorganic antibacterial materials into solid particles and evaluating their antibacterial efficacy in static aquatic environments, aiming to develop continuous purification technologies. For example, patent CN 116918831 A discloses a silver-loaded antibacterial slow-release material, but its framework is mainly composed of silica and quartz, with silver existing in the form of silver oxide and metallic silver. Its release rate and long-lasting effect still have room for optimization. Patent CN202410769129A focuses on organic / inorganic composite antibacterial and deodorizing particles, achieving slow release through polymer coating. However, its structural stability under long-term immersion and performance stability in complex water qualities (such as those containing detergent residues) require further investigation.

[0005] Therefore, developing an antibacterial slow-release product that combines long-lasting antibacterial properties, structural stability, safety, and suitability for cleaning equipment tanks is of significant practical importance. Summary of the Invention

[0006] The purpose of this invention is to provide a ceramic-based antibacterial sustained-release ball to solve the above-mentioned technical problems existing in the prior art.

[0007] A ceramic-based antibacterial slow-release ball is formed by sintering the following raw materials in the indicated mass percentages: 78-85.5% ceramic matrix, 10-15% pore structure regulator, 1.5-3.6% antibacterial active component, and 2-3% auxiliary functional component;

[0008] The pore structure regulator is used to form a multi-level pore structure during sintering to control the release rate of antibacterial active components.

[0009] The slow-release spheres of this invention use ceramic as a matrix. By forming a multi-level porous structure and loading antibacterial components during the sintering process, the controlled and slow release of silver ions is achieved, thereby achieving a long-lasting antibacterial effect.

[0010] Furthermore, the ceramic matrix comprises kaolin, aluminum silicate, and aluminum oxide;

[0011] Based on the mass of ceramic-based antibacterial slow-release balls as 100%, the amount of kaolin is 30-40%, the amount of aluminum silicate is 15-25%, and the amount of alumina is 5-10%.

[0012] The ceramic matrix, as the main body of the slow-release spheres, forms a stable three-dimensional network framework after high-temperature sintering, providing the main mechanical strength of the product and serving as a carrier for other functional components. Its total content is fundamental to ensuring the structural strength of the product.

[0013] Furthermore, the pore structure regulator includes natural polymers, calcium carbonate, and porous silicates;

[0014] Based on the mass of ceramic-based antibacterial sustained-release balls as 100%, the amount of natural polymer is 5-8%, the amount of calcium carbonate is 3-5%, and the amount of porous silicate is 2-4%.

[0015] In some specific embodiments, the natural polymer is starch or cellulose.

[0016] Starch / cellulose decomposes to form macroscopic pores; calcium carbonate decomposes to form micron-sized channels; porous silicates provide inherent nanoscale pores. These three components work synergistically to control the release rate of silver ions.

[0017] Furthermore, the antibacterial active ingredients include silver-loaded zeolite and nano-silver;

[0018] Based on the mass of ceramic-based antibacterial sustained-release balls as 100%, the amount of silver-loaded zeolite is 0.5-1.5%, and the amount of nano-silver is 0-0.5%.

[0019] In some preferred embodiments, the amount of nano-silver used is ≤0.1%.

[0020] Silver-supported zeolite achieves long-lasting, sustained release of silver ions through ion exchange; nano-silver provides rapid initial bactericidal activity. The two work synergistically to achieve "rapid onset and long-lasting effect." As the main antibacterial component, silver-supported zeolite interacts with other cations in the water (such as Ca) through the silver ions in its zeolite framework. 2+ Mg 2+ The key to achieving long-lasting antibacterial effects in this invention is the slow exchange of silver ions, enabling controlled and sustained release.

[0021] Furthermore, the auxiliary functional components include maifanite and refractory activated carbon;

[0022] Based on the mass of ceramic-based antibacterial slow-release balls as 100%, the amount of maifanite is 1-3%, and the amount of calcinable activated carbon is 0-1%.

[0023] Maifan stone can fine-tune water quality and adsorb harmful substances; calorie-resistant activated carbon is used to assist in adsorbing odor molecules and improve the deodorization effect.

[0024] Furthermore, the particle size of the ceramic-based antibacterial sustained-release spheres is 3-4 mm.

[0025] This invention also provides a method for preparing ceramic-based antibacterial sustained-release spheres, comprising the following steps:

[0026] Step 1) Raw material mixing and fine grinding: Place the ceramic matrix, pore structure regulator, antibacterial active component and auxiliary functional component in a ball mill and mix them evenly. Control the particle size D50 of the mixed powder to be ≤15μm.

[0027] Step 2) Molding and granulation: Add water to the powder, mix it evenly in a plywood machine, and then granulate it through a granulator, controlling the particle size within the range of 3~4 mm;

[0028] Step 3) Segmented sintering: The formed green pellets are placed in a sintering furnace for segmented sintering;

[0029] Step 4) Cooling and post-treatment: Cool to room temperature in the furnace to obtain ceramic-based antibacterial slow-release spheres.

[0030] Furthermore, the specific process of segmented sintering in step 3) is as follows:

[0031] First stage: Increase the temperature from room temperature to 450-550℃ at a rate of 3-5℃ / min, and hold for 30-60 minutes to allow the pore structure regulator to fully decompose and volatilize, forming the initial pores;

[0032] The second stage involves continuing to raise the temperature to 900-1050℃ at a rate of 2-4℃ / min and holding it for 60-120 minutes to allow the ceramic matrix to be fully sintered and solidified, forming a stable porous ceramic framework, and stably immobilizing the antibacterial active components within the porous ceramic framework.

[0033] Furthermore, in step 2), the amount of water used is 15-20% of the powder mass.

[0034] The method of this invention first forms a multi-level porous structure through a first-stage sintering process, and then performs a second-stage high-temperature sintering at 900-1050℃, which gives the ceramic matrix high mechanical strength and chemical stability. Under long-term water immersion, water flow impact and water quality changes (such as weak acid and weak alkali) environments, it can maintain the integrity of the particle shape, without pulverizing or disintegrating, ensuring long-term use.

[0035] The beneficial effects of this invention are as follows:

[0036] This invention constructs a stable three-dimensional network framework using a ceramic matrix, and firmly immobilizes antibacterial components such as silver-loaded zeolite within the framework and its pores. Under water immersion conditions, silver ions are slowly and controllably released through the micropores, avoiding short-term failure caused by explosive release, and achieving a continuous antibacterial effect for several months.

[0037] The raw materials used in this invention are all environmentally friendly, and the release concentration is within the range commonly used in published literature and related products. The introduction of maifan stone can also fine-tune water quality and adsorb some harmful substances. Moreover, it is easy to use; the granular product can be directly added to the water tank of the cleaning equipment without changing the original structure of the equipment or requiring frequent additions or replacements, greatly improving the user experience. Attached Figure Description

[0038] Figure 1 This is a picture of the sample's appearance;

[0039] Figure 2 The effect of different dosages and soaking times of antibacterial balls on the concentration of silver ions released;

[0040] Figure 3 Silver ion release curve under daily water changes:

[0041] Figure 4 The effect of water quality on the release of silver ions;

[0042] Figure 5 This is a test of the long-term release stability of the antibacterial sustained-release balls in Example 1;

[0043] Figure 6 These are electron microscope scans of Example 1 and Comparative Example 1. Detailed Implementation

[0044] The following specific embodiments illustrate the implementation of the invention. Those skilled in the art can easily understand other advantages and effects of the invention from the content disclosed in this specification.

[0045] Exemplary embodiments of the invention are now described with reference to the accompanying drawings. However, the invention may be embodied in many different forms and is not limited to the embodiments described herein. These embodiments are provided to fully and completely disclose the invention and to fully convey its scope to those skilled in the art. The terminology used in the exemplary embodiments illustrated in the drawings is not intended to limit the invention.

[0046] Unless otherwise stated, the terms used herein (including technical terms) have their common meaning as understood by one of ordinary skill in the art. Furthermore, it is understood that terms defined in commonly used dictionaries should be understood to have a meaning consistent with the context of their relevant field, and not to be interpreted as having an idealized or overly formal meaning.

[0047] Example 1

[0048] This embodiment provides a ceramic-based antibacterial sustained-release ball, which is formed by sintering the following raw materials in the following mass percentages: 80% ceramic matrix, 15% pore structure regulator, 2% antibacterial active component, and 3% auxiliary functional component.

[0049] In this embodiment, based on the mass of the ceramic-based antibacterial sustained-release spheres as 100%, the ceramic matrix consists of 40% kaolin, 25% aluminum silicate, and 15% alumina; the pore structure regulator consists of 7% starch, 5% calcium carbonate, and 3% porous silicate; the antibacterial active component is 2% silver-supported zeolite; and the auxiliary functional component consists of 2% maifanite and 1% heat-resistant activated carbon.

[0050] Preparation method:

[0051] S1. Place the above raw materials in a planetary ball mill and ball mill for 2 hours using deionized water as the medium to obtain a uniform slurry. After spray drying, obtain a mixed powder with a particle size D50 of about 10 μm.

[0052] S2. Add about 15% deionized water to the powder, mix it evenly in a ply mill, and then granulate it through an extrusion granulator to make spherical green bodies with a diameter of about 3-4 mm.

[0053] S3. Place the green billet in a sintering furnace, first raise the temperature to 500℃ at 4℃ / min and hold for 45 minutes; then raise the temperature to 980℃ at 3℃ / min and hold for 90 minutes.

[0054] S4. After sintering, the ceramic antibacterial slow-release balls are cooled to room temperature in the furnace to obtain the finished product.

[0055] Example 2

[0056] This embodiment provides a ceramic-based antibacterial sustained-release ball, which is formed by sintering the following raw materials in the indicated mass percentages: 79.5% ceramic matrix, 15% pore structure regulator, 2.5% antibacterial active component, and 3% auxiliary functional component.

[0057] In this embodiment, based on the mass of the ceramic-based antibacterial sustained-release spheres as 100%, the ceramic matrix consists of 38% kaolin, 25% aluminum silicate, and 16.5% alumina; the pore structure regulator consists of 8% cellulose, 4% calcium carbonate, and 3% porous silicate; the antibacterial active component consists of 2% silver-supported zeolite and 0.5% nano-silver; and the auxiliary functional component consists of 2% maifanite and 1% heat-resistant activated carbon.

[0058] Preparation method:

[0059] Example 2 differs from Example 1 in that it involves segmented sintering, but the rest of the process is the same. The specific process of segmented sintering is as follows:

[0060] The green billet is placed in a sintering furnace and heated from room temperature to 550°C at a rate of 5°C / min, held for 30 minutes, and then heated to 1050°C at a rate of 4°C / min, held for 60 minutes.

[0061] Example 3

[0062] This embodiment provides a ceramic-based antibacterial sustained-release ball, which is formed by sintering the following raw materials in the indicated mass percentages: 85.5% ceramic matrix, 10% pore structure regulator, 1.5% antibacterial active component, and 3% auxiliary functional component.

[0063] In this embodiment, based on the mass of the ceramic-based antibacterial sustained-release spheres as 100%, the ceramic matrix consists of 42% kaolin, 28.5% aluminum silicate, and 15% alumina; the pore structure regulator consists of 5% starch, 3% calcium carbonate, and 2% zeolite powder (porous silicate); the antibacterial active component is 1.5% silver-loaded zeolite; and the auxiliary functional component is 3% maifanite.

[0064] Preparation method:

[0065] Example 3 differs from Example 1 in that it involves segmented sintering, but the rest of the process is the same. The specific process of segmented sintering is as follows:

[0066] The green blanks are placed in a sintering furnace and heated from room temperature to 450°C at a rate of 3°C / min, held for 60 minutes, and then heated to 900°C at a rate of 2°C / min, held for 120 minutes.

[0067] Comparative Example 1

[0068] Compared with Example 1, Comparative Example 1 did not add pore structure regulators (starch, calcium carbonate, porous silicate), while the remaining components and preparation process remained unchanged. The resulting product had extremely low porosity, an excessively rapid silver ion release rate, and good initial antibacterial effect, but the antibacterial rate significantly decreased to below 70% after 30 days.

[0069] Comparative Example 2

[0070] Compared to Example 1, Comparative Example 2 reduced the maximum sintering temperature to 850°C, while keeping the other components and preparation process unchanged. The resulting product had an insufficiently sintered ceramic skeleton with poor mechanical strength. After being soaked in water for one month, it exhibited significant pulverization, its structural integrity was compromised, and it showed no antibacterial effect.

[0071] Comparative Example 3

[0072] Compared to Example 1, Comparative Example 3 did not use silver-supported zeolite; instead, equal amounts of silver nitrate powder were directly physically mixed. During the sintering process, a large amount of silver nitrate decomposed and volatilized, resulting in a final product with extremely low and unevenly distributed silver content, weak antibacterial effect, and no antibacterial effect against Escherichia coli and Candida albicans.

[0073] To further illustrate the effects of the present invention, the ceramic antibacterial balls prepared in Examples 1-3 and Comparative Examples 1-3 (such as...) were compared. Figure 1 The following performance tests were conducted (as shown in the figure). The experimental results are shown in Table 1 and Table 2.

[0074] I. Antibacterial properties:

[0075] Referring to the standard QB / T 2738-2023, the effective concentration was 1 g / L. The antibacterial rates against Escherichia coli, Candida albicans, and Staphylococcus aureus were tested after 24 hours and after continuous soaking for 30 and 60 days.

[0076] II. Long-lasting antibacterial performance: Referring to the standard QB / T 2738-2023, the effective concentration was 1g / L, and the antibacterial rate against Escherichia coli was tested after continuous soaking for 30 days and 60 days.

[0077] III. Structural stability: The sample was placed in a simulated wastewater solution (containing surfactants) from a sweeping robot and soaked at room temperature for 3 months. The changes in particle morphology were observed and the breakage rate was tested.

[0078] Table 1 Antibacterial rate

[0079]

[0080]

[0081] As shown in Tables 1 and 2, the ceramic-based antibacterial sustained-release spheres prepared in Examples 1, 2, and 3 of this invention are significantly superior to the comparative examples in terms of antibacterial longevity, structural stability, and silver ion sustained-release performance, fully meeting the long-term antibacterial requirements of water tanks in cleaning equipment. Comparative Example 1, due to the lack of a pore structure modifier, resulted in extremely low porosity, obstructing the silver ion release channels. Initially, only surface-exposed silver species dissolved, exhibiting a temporary high antibacterial effect; due to the lack of internal interconnected channels, internal silver could not continuously migrate outwards, leading to a rapid decline in antibacterial performance and poor longevity. This demonstrates that a multi-level pore structure is crucial for achieving sustained release. Figure 6 As shown in the scanning electron microscope images of Example 1 and Comparative Example 1, Example 1 exhibits abundant, interconnected micron- and submicron-sized channels. These channels are uniformly distributed, forming a typical three-dimensional network structure. This hierarchical channel structure provides ideal pathways for water molecule wetting and the slow diffusion of silver ions. In contrast, Comparative Example 1 displays an extremely dense, almost poreless microstructure. The ceramic particles are fully fused together due to high-temperature sintering, but lack inherent channels created by the decomposition of the pore-forming agent.

[0082] Comparative Example 2, due to insufficient sintering temperature, failed to fully form the ceramic framework, resulting in a loose structure. It easily pulverized in water, leading to the loss of antibacterial components and particle disintegration, demonstrating the necessity of high-temperature sintering for obtaining a stable framework. Comparative Example 3, by directly mixing silver nitrate, caused the silver nitrate to decompose at the high sintering temperature (2AgNO3 → 2Ag + 2NO2 + O2), resulting in significant silver loss and uneven distribution. The remaining silver could not be released sustainably, demonstrating the superiority of using thermally stable silver-supported zeolite as an antibacterial precursor.

[0083] Both Example 2 (containing nano-silver) and Example 1 (without nano-silver) exhibited excellent antibacterial rates, with no significant difference between them. This indicates that silver-supported zeolite is the key component for long-lasting antibacterial action in the system of this invention. The addition of nano-silver aims to improve the initial bactericidal rate, but its contribution to the antibacterial rate after 24 hours is limited; its superior effect may be reflected in antibacterial tests at shorter time intervals (e.g., 2 hours).

[0084] Table 2 Antibacterial rates after 30 days and 60 days

[0085]

[0086] The antibacterial sustained-release beads prepared in Example 1 were soaked in deionized water at concentrations of 1 g / L, 1.5 g / L, and 2 g / L, respectively. The silver ion content in the solution was measured by ICP-OES at different soaking times. The results showed that the silver ion concentration was positively correlated with time and dosage. As the soaking time increased (0.5 h → 168 h), the silver ion concentration continuously increased, indicating that Example 1 has sustained-release properties in water. Furthermore, at the same soaking time, the higher the dosage of Example 1 (1 g / L → 2 g / L), the higher the release concentration. Figure 2 As shown, different dosages and soaking times affect the concentration of silver ions released.

[0087] The antibacterial sustained-release beads prepared in Example 1 were soaked in deionized water at a dosage of 1 g / L, with the water changed daily, and the silver ion concentration in the solution measured. The results showed that the daily concentration remained stable between 0.042 and 0.052 ppm, maintaining a stable low-concentration release. The results are as follows... Figure 3 As shown.

[0088] The antibacterial sustained-release beads prepared in Example 1 were soaked in different water qualities at a dosage of 1 g / L, and the concentration of silver ions in the solution was measured after 24 hours. Figure 4 As shown, the results indicate that the higher the TDS, the more inhibited the release of silver ions. This is because water bodies with higher TDS contain more Cl... - SO4 2- Anions readily aggregate with the silver ions released in Example 1, leading to a decrease in the concentration of free silver ions in the solution. However, even in tap water with a high TDS of 600-700 ppm, the concentration of silver ions released in Example 1 can reach 0.0341 ppm, demonstrating a significant antibacterial effect.

[0089] The antibacterial sustained-release beads prepared in Example 1 were soaked in deionized water at a dosage of 1 g / L. The water was checked and changed every 7 days. During the long-term soaking test of 64 days, the silver ion release concentration fluctuated between 0.0407 and 0.0517 ppm, without a significant decreasing trend. This indicates that Example 1 has good long-term sustained-release performance.

[0090] The examples above are merely illustrative of the invention and do not constitute a limitation on the scope of protection of the invention. Any design that is the same as or similar to the invention falls within the scope of protection of the invention.

Claims

1. A ceramic-based antibacterial sustained-release ball, characterized in that, It is formed by sintering the following raw materials in the indicated mass percentages: ceramic matrix 78~85.5%, pore structure regulator 10~15%, antibacterial active component 1.5~3.6%, and auxiliary functional component 2~3%; The pore structure regulator is used to form a multi-level pore structure during sintering to control the release rate of antibacterial active components.

2. The ceramic-based antibacterial sustained-release ball according to claim 1, characterized in that, The ceramic matrix includes kaolin, aluminum silicate and aluminum oxide; Based on the mass of ceramic-based antibacterial slow-release balls as 100%, the amount of kaolin is 30-40%, the amount of aluminum silicate is 15-25%, and the amount of alumina is 5-10%.

3. The ceramic-based antibacterial sustained-release ball according to claim 1, characterized in that: The pore structure regulator includes natural polymers, calcium carbonate, and porous silicates; Based on the mass of ceramic-based antibacterial sustained-release balls as 100%, the amount of natural polymer is 5-8%, the amount of calcium carbonate is 3-5%, and the amount of porous silicate is 2-4%.

4. The ceramic-based antibacterial sustained-release ball according to claim 1, characterized in that: The antibacterial active ingredients include silver-loaded zeolite and nano-silver; Based on the mass of ceramic-based antibacterial sustained-release balls as 100%, the amount of silver-loaded zeolite is 0.5-1.5%, and the amount of nano-silver is 0-0.5%.

5. The ceramic-based antibacterial sustained-release ball according to claim 1, characterized in that: The auxiliary functional components include maifanite and refractory activated carbon; Based on the mass of ceramic-based antibacterial slow-release balls as 100%, the amount of maifanite is 1-3%, and the amount of calcinable activated carbon is 0-1%.

6. A ceramic-based antibacterial sustained-release ball according to any one of claims 1 to 5, characterized in that: The ceramic-based antibacterial sustained-release spheres have a particle size of 3-4 mm.

7. A method for preparing ceramic-based antibacterial sustained-release spheres as described in any one of claims 1 to 6, characterized in that, Includes the following steps: Step 1) Raw material mixing and fine grinding: Place the ceramic matrix, pore structure regulator, antibacterial active component and auxiliary functional component in a ball mill and mix them evenly. Control the particle size D50 of the mixed powder to be ≤15μm. Step 2) Molding and granulation: Add water to the powder, mix it evenly in a plywood machine, and then granulate it through a granulator, controlling the particle size within the range of 3~4 mm; Step 3) Segmented sintering: The formed green pellets are placed in a sintering furnace for segmented sintering; Step 4) Cooling and post-treatment: Cool to room temperature in the furnace to obtain ceramic-based antibacterial slow-release spheres.

8. The method for preparing a ceramic-based antibacterial sustained-release ball according to claim 7, characterized in that: Step 3) The specific process of segmented sintering is as follows: First stage: Increase the temperature from room temperature to 450-550℃ at a rate of 3-5℃ / min, and hold for 30-60 minutes to allow the pore structure regulator to fully decompose and volatilize, forming the initial pores; The second stage involves continuing to raise the temperature to 900-1050℃ at a rate of 2-4℃ / min and holding it for 60-120 minutes to allow the ceramic matrix to be fully sintered and solidified, forming a stable porous ceramic framework, and stably immobilizing the antibacterial active components within the porous ceramic framework.

9. The method for preparing a ceramic-based antibacterial sustained-release ball according to claim 7, characterized in that: In step 2), the amount of water used is 15-20% of the powder mass.

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