Antibacterial silica gel material and preparation method thereof

Abstract

The invention relates to the technical field of organic silicon materials, in particular to an antibacterial silica gel material and a preparation method thereof, and aims at solving the problems that in an existing antibacterial silica gel material, an antibacterial agent is poor in dispersity, the antibacterial durability is insufficient, and the mechanical property is affected. The antibacterial silica gel material is prepared from the following raw materials: an amino modified silicone rubber matrix, SiO2 coated-Cu coated CuO composite particles, a polyether modified polysiloxane dispersant and a vulcanizing agent, and the preparation method comprises the following steps: preparation of the amino modified silicone rubber matrix, preparation of the SiO2 coated-Cu coated CuO composite particles, segmented mixing of a composite rubber material, and vulcanization molding. Through raw material modification and process optimization, the antibacterial rate of the material to escherichia coli and staphylococcus aureus reaches 99% or above, the antibacterial performance is stable after recycling, the tensile strength is larger than or equal to 8.6 MPa, the elongation at break is larger than or equal to 520%, and the material can be widely applied to the fields of food contact appliances, daily protection articles and the like.

Description

Technical Field

[0001] This invention relates to the field of organosilicon materials technology, and in particular to an antibacterial silicone material and its preparation method. Background Technology

[0002] Silicone materials are widely used in various fields such as medical, food contact, and daily necessities due to their excellent resistance to high and low temperatures, flexibility, and biocompatibility. However, traditional silicone materials do not possess antibacterial properties and can easily become a breeding ground for bacteria, fungi, and other microorganisms during use. This can lead to material aging and deterioration, and may also cause safety hazards such as cross-infection.

[0003] In existing technologies, organic antibacterial agents or inorganic antibacterial particles are often added to impart antibacterial properties to silicone. However, organic antibacterial agents suffer from poor heat resistance, volatility, and insufficient antibacterial durability. Inorganic antibacterial particles, such as copper-based and silver-based particles, while providing long-lasting antibacterial protection, tend to agglomerate in the silicone matrix, exhibiting poor dispersibility. This not only affects the mechanical properties of the silicone material but also leads to uneven antibacterial effects. Furthermore, inorganic antibacterial particles have poor interfacial compatibility with the silicone matrix, and with prolonged use, they are prone to detaching from the matrix, further reducing antibacterial stability.

[0004] Therefore, based on the relevant technologies mentioned above, there is an urgent need to develop an antibacterial silicone material and its preparation method. Summary of the Invention

[0005] In view of this, the purpose of this invention is to provide an antibacterial silicone material and its preparation method, so as to solve the problems of poor dispersibility of antibacterial agents, insufficient antibacterial durability and affected mechanical properties in existing antibacterial silicone materials.

[0006] To achieve the above objectives, the present invention provides an antibacterial silicone material and a method for preparing the same.

[0007] An antibacterial silicone material, wherein the antibacterial silicone material is prepared from the following raw materials in parts by weight: 100 parts of amino-modified silicone rubber matrix, 10-18 parts of SiO2-coated Cu@CuO composite particles, 0.6-1.2 parts of polyether-modified polysiloxane dispersant, and 1.0-1.6 parts of vulcanizing agent; The amino-modified silicone rubber matrix is ​​formed by modifying methyl vinyl silicone rubber with γ-aminopropyltriethoxysilane, with an amino grafting rate of 3.0-4.5 μmol / cm² and a surface hydroxyl conversion rate of ≥80%. The SiO2-coated Cu@CuO composite particles have a core-shell structure. The core is Cu@CuO, and the mass ratio of Cu to CuO in Cu@CuO is 1:3 with a particle size of 60-160 nm. The outer shell is a SiO2 coating layer with a thickness of 10-20 nm.

[0008] Preferably, the preparation process of the SiO2-coated Cu@CuO composite particles is as follows: Step P1. Mix glucose with CuSO4 and reduce CuSO4 with glucose to generate Cu nanoparticles; Step P2. Mix Cu nanoparticles with NaOH and oxidize them with NaOH to form a Cu@CuO core; Step P3. Coating the Cu@CuO core using the tetraethyl orthosilicate sol-gel method; Step P4. The coated particles are modified by γ-aminopropyltriethoxysilane grafting to obtain SiO2-coated Cu@CuO composite particles; The mass ratio of tetraethyl orthosilicate to Cu@CuO is 1:5-7; The SiO2 coating has a pore size of 2-5 nm.

[0009] Preferably, the preparation process of Cu@CuO core in step P2 is as follows: 0.1 mol / L copper sulfate solution and glucose solution are mixed, with a molar ratio of glucose solution to CuSO4 of 1:1. The mixture is stirred at 60°C for 2 hours to generate Cu nanoparticles. Then, the temperature is raised to 80°C, and 0.05 mol / L sodium hydroxide solution is added dropwise at a rate of 1 mL / min. After the addition is completed, the mixture is reacted for 3 hours to obtain Cu@CuO core. The particle size of Cu@CuO core is 60-160 nm.

[0010] Preferably, the coating process in step P3 is as follows: the Cu@CuO core is dispersed in an ethanol-water mixture with a volume ratio of ethanol to water of 4:1. Then, tetraethyl orthosilicate is added with a mass ratio of tetraethyl orthosilicate to Cu@CuO of 1:5-7. The pH of the system is adjusted to 8.0 with ammonia. The mixture is stirred at 40-50°C for 5-7 hours. After the reaction, a SiO2 coating layer is formed with a thickness of 10-20 nm and a porosity of 15%-25%.

[0011] Preferably, the preparation process of the amino-modified silicone rubber matrix is ​​as follows: Methyl vinyl silicone rubber was immersed in an ethanol-water mixture of 6-8 wt% γ-aminopropyltriethoxysilane, wherein the vinyl content of the methyl vinyl silicone rubber was 0.2-0.4 wt%, and the volume ratio of ethanol to water in the ethanol-water mixture was 9:1. The reaction was carried out at 55-65℃ with shaking at 150 rpm for 4-6 hours. After the reaction, the rubber was washed three times with deionized water and then vacuum dried at 60℃ for 8 hours to obtain an amino-modified silicone rubber matrix.

[0012] Preferably, the polyether-modified polysiloxane dispersant has a number average molecular weight of 4000-6000, and the polyether segment in the polyether-modified polysiloxane dispersant is an ethylene oxide segment, with the ethylene oxide segment accounting for 35-45 wt%.

[0013] Preferably, the vulcanizing agent is a compound of dicumyl peroxide and triallyl isocyanurate in a mass ratio of 4:1.

[0014] A method for preparing an antibacterial silicone material includes the following steps: Step S1. Preparation of amino-modified silicone rubber matrix; Step S2. Preparation of SiO2-coated Cu@CuO composite particles; Step S3. Preparation of composite rubber compound: The amino-modified silicone rubber matrix is ​​added to a two-roll mill for mixing. The rolling temperature of the two-roll mill is 45-55℃ and the rolling gap is 0.8-1.2mm. The mixing time is 4-6min. Then, a dispersant is added and mixing is continued for 2-3min. Then, SiO2-coated Cu@CuO composite particles are added in 2-3 batches, and mixing is carried out for 4-5min after each addition of SiO2-coated Cu@CuO composite particles. Finally, a vulcanizing agent is added and mixing is carried out for 6-8min to obtain the composite rubber compound. Step S4. Vulcanization molding: The composite rubber compound is first pre-pressed at a temperature of 70-80℃ and a pressure of 2-4MPa for 8-12 minutes, and then vulcanized at a temperature of 140-150℃ and a pressure of 6-8MPa for 20-25 minutes; after vulcanization, it is cooled and demolded to obtain antibacterial silicone material.

[0015] Preferably, the mixing parameters of the open mill in step S3 are: roll temperature fluctuation ≤ ±2℃, roll gap fluctuation ≤ ±0.1mm.

[0016] Preferably, the heating rate during vulcanization in step S4 is 8-12℃ / min, the cooling rate is 4-6℃ / min, and the pressure fluctuation during vulcanization is ≤±0.2MPa.

[0017] The core function of amino-modified silicone rubber matrix is ​​to improve interfacial compatibility with antibacterial particles. The amino groups on the modified matrix surface can form hydrogen bonds or chemical interactions with the hydroxyl groups (SiO2 layer) or amino groups (grafted modification layer) on the surface of SiO2-coated Cu@CuO composite particles, reducing the aggregation of antibacterial particles in the matrix. Simultaneously, the high hydroxyl conversion rate (≥80%) ensures sufficient modification of the matrix surface, avoiding the weak interfacial bonding caused by unmodified hydroxyl groups, thus laying the foundation for the material's excellent mechanical properties and antibacterial stability. The core (Cu@CuO) of the SiO2-coated Cu@CuO composite particles primarily provides antibacterial activity, where Cu and CuO slowly release Cu 2+It kills pathogenic bacteria such as Escherichia coli and Staphylococcus aureus by disrupting bacterial cell membranes and inhibiting enzyme activity. A Cu to CuO mass ratio of 1:3 and a particle size of 60-160 nm optimize antibacterial activity and dispersibility, preventing agglomeration due to excessively large particle size or loss due to excessively small particle size. The outer shell (SiO2 coating layer) provides a dual function of "protection + controlled release." The 10-20 nm thick SiO2 layer prevents the Cu@CuO core from corroding or detaching during processing / use, improving antibacterial durability. A 2-5 nm pore size and 15%-25% porosity of Cu... 2+ It provides a slow release channel to avoid the short-term failure problem caused by the one-time release of antibacterial ingredients; the final surface grafting modification further enhances the compatibility with the amino-modified silicone rubber matrix, and further reduces the risk of particle agglomeration through the interaction of amino groups.

[0018] The core function of polyether-modified polysiloxane dispersants is to optimize the dispersibility of antibacterial particles. A number-average molecular weight of 4000-6000 balances the dispersant's solubility and adsorption capacity in a silica matrix, avoiding unstable dispersion due to excessively small molecular weight and decreased matrix compatibility due to excessively large molecular weight. The 35-45 wt% ethylene oxide segments possess both hydrophilic and siloxane-philic properties, allowing them to adsorb onto the surface of SiO2-coated -Cu@CuO particles, forming a steric hindrance effect to prevent particle aggregation and ensure uniform distribution of the antibacterial effect without affecting the material's mechanical properties.

[0019] Compound vulcanizing agents can achieve efficient crosslinking and optimized mechanical properties of silicone matrix. Dicumyl peroxide, as an initiator, can decompose at the vulcanization temperature to generate free radicals, initiating crosslinking of silicone rubber molecular chains; triallyl isocyanurate, as a crosslinking aid, can increase crosslinking density and reduce crosslinking defects; the 4:1 compounding ratio balances vulcanization speed and crosslinking uniformity, avoiding insufficient vulcanization (low mechanical strength) or over-vulcanization (material embrittlement), ultimately improving the tensile strength and elongation at break of antibacterial silicone.

[0020] In the compound rubber preparation process, an open mill with a roller temperature of 45-55℃ (fluctuation ≤ ±2℃) and a roller gap of 0.8-1.2mm (fluctuation ≤ ±0.1mm) is used. The mixing sequence is "matrix (4-6min) → dispersant (2-3min) → antibacterial granules (in 2-3 batches, 4-5min each time) → vulcanizing agent (6-8min)". This operation ensures uniform mixing of all components and avoids agglomeration and premature vulcanization. The 45-55℃ roller temperature prevents the matrix from overheating and sticking to the rollers or the vulcanizing agent from decomposing prematurely. Roller temperature / roller gap fluctuation control (≤ ±2℃ / ±0.1mm) ensures process stability and avoids batch differences. The core logic of the segmented mixing sequence is: first, plasticize the matrix, then add the dispersant to make it evenly distributed; adding antibacterial granules in batches avoids agglomeration caused by adding them all at once; and finally, adding the vulcanizing agent reduces crosslinking loss during the mixing process.

[0021] The vulcanization molding process involves pre-compression at 70-80℃ and 2-4MPa for 8-12 minutes, followed by vulcanization at 140-150℃ and 6-8MPa for 20-25 minutes. The heating rate is 8-12℃ / min, the cooling rate is 4-6℃ / min, and the pressure fluctuation is ≤±0.2MPa. During the pre-compression stage, the low temperature of 70-80℃ and the low pressure of 2-4MPa help to expel air bubbles from the rubber compound, preventing porosity in the finished product. The 8-12 minute pre-compression time ensures that the air bubbles are fully released and allows the rubber compound to initially conform to the mold shape. Post-curing stage: High temperature of 140-150℃ and high pressure of 6-8MPa provide sufficient energy for the crosslinking reaction, and a reaction time of 20-25min ensures complete crosslinking of the matrix; controlling the heating rate (8-12℃ / min) can avoid uneven crosslinking caused by excessive local temperature, and controlling the cooling rate (4-6℃ / min) can prevent internal stress caused by excessive temperature difference in the finished product, reducing the risk of cracking or deformation; controlling pressure fluctuation (≤±0.2MPa) ensures uniform density and stable mechanical properties of the finished product.

[0022] The beneficial effects of this invention are: This invention provides an antibacterial silicone material and its preparation method. By using amino-modified silicone rubber as a matrix and combining it with SiO2-coated Cu@CuO composite particles, the interaction between amino groups and the surface groups of the antibacterial particles significantly improves the dispersion stability and interfacial compatibility of the antibacterial particles in the silicone matrix. The SiO2 coating layer not only protects the core antibacterial components from loss but also allows for slow release of the antibacterial components through its porous structure, prolonging the antibacterial effect. Simultaneously, a specific compound of vulcanizing agents and dispersants further optimizes the mechanical and processing properties of the material. Compared with existing technologies, the antibacterial silicone material prepared by this invention achieves an antibacterial rate of over 99% against common pathogenic bacteria such as Escherichia coli and Staphylococcus aureus, and its antibacterial performance remains stable after multiple cycles of use. It also possesses good tensile strength and flexibility, making it widely applicable in medical catheters, food contact devices, and daily protective equipment, with broad application prospects. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments.

[0024] Example 1: A method for preparing an antibacterial silicone material, comprising the following steps: S1. Preparation of amino-modified silicone rubber matrix: Methyl vinyl silicone rubber was immersed in an ethanol-water mixture of 6 wt% γ-aminopropyltriethoxysilane, wherein the vinyl content of the methyl vinyl silicone rubber was 0.2 wt%, and the volume ratio of ethanol to water in the ethanol-water mixture was 9:1. The reaction was carried out at 55℃ with shaking at 150 rpm for 4 h. After the reaction, the mixture was washed three times with deionized water and then vacuum dried at 60℃ for 8 h to obtain an amino-modified silicone rubber matrix. The amino grafting rate of the amino-modified silicone rubber matrix was 3.0 μmol / cm², and the surface hydroxyl conversion rate was ≥80%. Preparation of S2.SiO2-coated Cu@CuO composite particles: 0.1 mol / L copper sulfate solution and glucose solution were mixed, with a glucose solution to CuSO4 molar ratio of 1:1. The mixture was stirred at 60℃ for 2 h to generate Cu nanoparticles. Then, the temperature was raised to 80℃, and 0.05 mol / L sodium hydroxide solution was added dropwise at a rate of 1 mL / min. After the addition was complete, the reaction was carried out for 3 h to obtain Cu@CuO cores. The particle size of the Cu@CuO cores was 60-160 nm. The Cu@CuO cores were dispersed in an ethanol-water mixture. The volume ratio of ethanol to water in the ethanol-water mixture was 4:1. Then, tetraethyl orthosilicate was added, and the mass ratio of tetraethyl orthosilicate to Cu@CuO was 1:5. The pH of the system was adjusted to 8.0 with ammonia. The mixture was stirred at 40°C for 5 hours to form a SiO2 coating layer. The thickness of the SiO2 coating layer was 10-20 nm and the porosity was 15%-25%. The particles formed after coating were grafted with γ-aminopropyltriethoxysilane to obtain SiO2-coated Cu@CuO composite particles. The pore size of the SiO2 coating layer was 2-5 nm. S3. Preparation of composite compound: 100 parts of amino-modified silicone rubber matrix are added to a two-roll mill for mixing. The rolling temperature of the two-roll mill is 45℃ and the rolling gap is 0.8-1.2mm. The mixing time is 4min. Then, 0.6 parts of polyether-modified polysiloxane dispersant are added and the mixing continues for 2min. Then, SiO2-coated Cu@CuO composite particles are added in 2-3 batches. After each addition of SiO2-coated Cu@CuO composite particles, the mixing is carried out for 4min. The total amount of SiO2-coated Cu@CuO composite particles added is 10 parts. Finally, 1.0 part of vulcanizing agent was added and mixed for 6 minutes to obtain a composite rubber compound. The dispersant was a polyether-modified polysiloxane dispersant with a number average molecular weight of 4000-6000. The polyether segments in the polyether-modified polysiloxane dispersant were ethylene oxide segments, and the proportion of the ethylene oxide segments was 35 wt%. The vulcanizing agent was a compound of dicumyl peroxide and triallyl isocyanurate in a mass ratio of 4:1. The mixing parameters of the open mill were: roller temperature fluctuation ≤ ±2℃, and roller gap fluctuation ≤ ±0.1mm. S4. Vulcanization molding: The composite rubber compound is first pre-pressed at 70℃ and 2MPa for 8 minutes, and then vulcanized at 140℃ and 6MPa for 20 minutes. After vulcanization, it is cooled and demolded to obtain antibacterial silicone material. The heating rate during vulcanization is 8℃ / min, the cooling rate is 4℃ / min, and the pressure fluctuation during vulcanization is ≤±0.2MPa.

[0025] Example 2: A method for preparing an antibacterial silicone material, comprising the following steps: S1. Preparation of amino-modified silicone rubber matrix: Methyl vinyl silicone rubber was immersed in an ethanol-water mixture of 6.5 wt% γ-aminopropyltriethoxysilane, wherein the vinyl content of the methyl vinyl silicone rubber was 0.25 wt%, and the volume ratio of ethanol to water in the ethanol-water mixture was 9:1. The reaction was carried out at 58°C with shaking at 150 rpm for 4.5 h. After the reaction, the mixture was washed three times with deionized water and then vacuum dried at 60°C for 8 h to obtain an amino-modified silicone rubber matrix. The amino grafting rate of the amino-modified silicone rubber matrix was 3.5 μmol / cm², and the surface hydroxyl conversion rate was ≥80%. Preparation of S2.SiO2-coated Cu@CuO composite particles: 0.1 mol / L copper sulfate solution and glucose solution were mixed, with a glucose solution to CuSO4 molar ratio of 1:1. The mixture was stirred at 60℃ for 2 h to generate Cu nanoparticles. Then, the temperature was raised to 80℃, and 0.05 mol / L sodium hydroxide solution was added dropwise at a rate of 1 mL / min. After the addition was complete, the reaction was carried out for 3 h to obtain Cu@CuO cores. The particle size of the Cu@CuO cores was 60-160 nm. The Cu@CuO cores were dispersed in an ethanol-water mixture. The volume ratio of ethanol to water in the alcohol-water mixture is 4:1. Then, tetraethyl orthosilicate is added, and the mass ratio of tetraethyl orthosilicate to Cu@CuO is 1:5.5. The pH of the system is adjusted to 8.0 with ammonia. The mixture is stirred at 43°C for 5.5 hours. After the reaction, a SiO2 coating layer is formed with a thickness of 10-20 nm and a porosity of 15%-25%. The particles formed after coating are grafted with γ-aminopropyltriethoxysilane to obtain SiO2-coated Cu@CuO composite particles with a pore size of 2-5 nm. S3. Preparation of Composite Compound: 100 parts of amino-modified silicone rubber matrix were added to a two-roll mill for mixing. The two-roll mill temperature was 49℃ and the roll gap was 0.8-1.2mm. The mixing time was 5min. Then, 0.8 parts of polyether-modified polysiloxane dispersant were added and the mixture was mixed for another 2.5min. SiO2-coated Cu@CuO composite particles were then added in 2-3 batches, with each addition followed by 4.5min of mixing. The total amount of SiO2-coated Cu@CuO composite particles added was 13... 1.2 parts of vulcanizing agent were added and mixed for 7 minutes to obtain a composite rubber compound. The dispersant was a polyether-modified polysiloxane dispersant with a number average molecular weight of 4000-6000. The polyether segments in the polyether-modified polysiloxane dispersant were ethylene oxide segments, with the proportion of ethylene oxide segments being 39 wt%. The vulcanizing agent was a compound of dicumyl peroxide and triallyl isocyanurate in a mass ratio of 4:1. The mixing parameters of the open mill were: roller temperature fluctuation ≤ ±2℃, roller gap fluctuation ≤ ±0.1mm. S4. Vulcanization molding: The composite rubber compound is first pre-pressed at 73℃ and 3MPa for 9 minutes, and then vulcanized at 143℃ and 7MPa for 22 minutes. After vulcanization, the material is cooled and demolded to obtain antibacterial silicone material. The heating rate during vulcanization is 9℃ / min, the cooling rate is 4.5℃ / min, and the pressure fluctuation during vulcanization is ≤±0.2MPa.

[0026] Example 3: A method for preparing an antibacterial silicone material, comprising the following steps: S1. Preparation of amino-modified silicone rubber matrix: Methyl vinyl silicone rubber was immersed in an ethanol-water mixture of 7 wt% γ-aminopropyltriethoxysilane, wherein the vinyl content of the methyl vinyl silicone rubber was 0.3 wt%, and the volume ratio of ethanol to water in the ethanol-water mixture was 9:1. The reaction was carried out at 60℃ with shaking at 150 rpm for 5 h. After the reaction, the mixture was washed three times with deionized water and then vacuum dried at 60℃ for 8 h to obtain an amino-modified silicone rubber matrix. The amino grafting rate of the amino-modified silicone rubber matrix was 4 μmol / cm², and the surface hydroxyl conversion rate was ≥80%. Preparation of S2.SiO2-coated Cu@CuO composite particles: 0.1 mol / L copper sulfate solution and glucose solution were mixed, with a glucose solution to CuSO4 molar ratio of 1:1. The mixture was stirred at 60℃ for 2 h to generate Cu nanoparticles. Then, the temperature was raised to 80℃, and 0.05 mol / L sodium hydroxide solution was added dropwise at a rate of 1 mL / min. After the addition was complete, the reaction was carried out for 3 h to obtain Cu@CuO cores. The particle size of the Cu@CuO cores was 60-160 nm. The Cu@CuO cores were dispersed in an ethanol-water mixture. The volume ratio of ethanol to water in the ethanol-water mixture was 4:1. Then, tetraethyl orthosilicate was added, and the mass ratio of tetraethyl orthosilicate to Cu@CuO was 1:6. The pH of the system was adjusted to 8.0 with ammonia. The mixture was stirred at 46°C for 6 hours to form a SiO2 coating layer. The thickness of the SiO2 coating layer was 10-20 nm and the porosity was 15%-25%. The particles formed after coating were grafted with γ-aminopropyltriethoxysilane to obtain SiO2-coated Cu@CuO composite particles. The pore size of the SiO2 coating layer was 2-5 nm. S3. Preparation of Composite Compound: 100 parts of amino-modified silicone rubber matrix were added to a two-roll mill for mixing. The two-roll mill temperature was 52℃ and the roll gap was 0.8-1.2 mm. The mixing time was 5 min. Then, 1.0 part of polyether-modified polysiloxane dispersant was added and mixing was continued for 3 min. Then, SiO2-coated Cu@CuO composite particles were added in 2-3 batches, and mixing was carried out for 5 min after each addition of SiO2-coated Cu@CuO composite particles. The total amount of SiO2-coated Cu@CuO composite particles added was 16 parts. Then, 1.4 parts of vulcanizing agent were added and mixed for 7.5 minutes to obtain a composite rubber compound. The dispersant was a polyether-modified polysiloxane dispersant with a number average molecular weight of 4000-6000. The polyether segments in the polyether-modified polysiloxane dispersant were ethylene oxide segments, and the proportion of the ethylene oxide segments was 42 wt%. The vulcanizing agent was a compound of dicumyl peroxide and triallyl isocyanurate in a mass ratio of 4:1. The mixing parameters of the open mill were: roller temperature fluctuation ≤ ±2℃, and roller gap fluctuation ≤ ±0.1mm. S4. Vulcanization molding: The composite rubber compound is first pre-pressed at 76℃ and 3MPa for 10 minutes, and then vulcanized at 146℃ and 7MPa for 24 minutes. After vulcanization, the material is cooled and demolded to obtain antibacterial silicone material. The heating rate during vulcanization is 10℃ / min, the cooling rate is 5℃ / min, and the pressure fluctuation during vulcanization is ≤±0.2MPa.

[0027] Example 4: A method for preparing an antibacterial silicone material, comprising the following steps: S1. Preparation of amino-modified silicone rubber matrix: Methyl vinyl silicone rubber was immersed in an ethanol-water mixture of 8 wt% γ-aminopropyltriethoxysilane, wherein the vinyl content of the methyl vinyl silicone rubber was 0.4 wt%, and the volume ratio of ethanol to water in the ethanol-water mixture was 9:1. The reaction was carried out at 65℃ with shaking at 150 rpm for 6 h. After the reaction, the mixture was washed three times with deionized water and then vacuum dried at 60℃ for 8 h to obtain an amino-modified silicone rubber matrix. The amino grafting rate of the amino-modified silicone rubber matrix was 4.5 μmol / cm², and the surface hydroxyl conversion rate was ≥80%. Preparation of S2.SiO2-coated Cu@CuO composite particles: 0.1 mol / L copper sulfate solution and glucose solution were mixed, with a glucose solution to CuSO4 molar ratio of 1:1. The mixture was stirred at 60℃ for 2 h to generate Cu nanoparticles. Then, the temperature was raised to 80℃, and 0.05 mol / L sodium hydroxide solution was added dropwise at a rate of 1 mL / min. After the addition was complete, the reaction was carried out for 3 h to obtain Cu@CuO cores. The particle size of the Cu@CuO cores was 60-160 nm. The Cu@CuO cores were dispersed in an ethanol-water mixture. The volume ratio of ethanol to water in the ethanol-water mixture was 4:1. Then, tetraethyl orthosilicate was added, and the mass ratio of tetraethyl orthosilicate to Cu@CuO was 1:7. The pH of the system was adjusted to 8.0 with ammonia. The mixture was stirred at 50°C for 7 hours to form a SiO2 coating layer. The thickness of the SiO2 coating layer was 10-20 nm and the porosity was 15%-25%. The particles formed after coating were grafted with γ-aminopropyltriethoxysilane to obtain SiO2-coated Cu@CuO composite particles. The pore size of the SiO2 coating layer was 2-5 nm. S3. Preparation of composite compound: 100 parts of amino-modified silicone rubber matrix were added to a two-roll mill for mixing. The rolling temperature of the two-roll mill was 55℃ and the rolling gap was 0.8-1.2 mm. The mixing time was 6 min. Then, 1.2 parts of polyether-modified polysiloxane dispersant were added and the mixture was mixed for another 3 min. Then, SiO2-coated Cu@CuO composite particles were added in 2-3 batches. After each addition of SiO2-coated Cu@CuO composite particles, the mixture was mixed for 5 min. The total amount of SiO2-coated Cu@CuO composite particles added was 18 parts. Finally, 1.6 parts of vulcanizing agent were added and mixed for 8 minutes to obtain a composite rubber compound. The dispersant was a polyether-modified polysiloxane dispersant with a number average molecular weight of 4000-6000. The polyether segments in the polyether-modified polysiloxane dispersant were ethylene oxide segments, and the proportion of the ethylene oxide segments was 45 wt%. The vulcanizing agent was a compound of dicumyl peroxide and triallyl isocyanurate in a mass ratio of 4:1. The mixing parameters of the open mill were: roller temperature fluctuation ≤ ±2℃, and roller gap fluctuation ≤ ±0.1mm. S4. Vulcanization molding: The composite rubber compound is first pre-pressed at 80℃ and 4MPa for 12 minutes, and then vulcanized at 150℃ and 8MPa for 25 minutes. After vulcanization, the material is cooled and demolded to obtain antibacterial silicone material. The heating rate during vulcanization is 12℃ / min, the cooling rate is 4-6℃ / min, and the pressure fluctuation during vulcanization is ≤±0.2MPa.

[0028] Comparative Example 1: Compared with Example 1, this comparative example did not add SiO2-coated Cu@CuO composite particles during the preparation of the antibacterial silicone material. All other steps and parameters were the same, and will not be repeated here. The final antibacterial silicone material was obtained.

[0029] Comparative Example 2: Compared with Example 1, this comparative example only replaces "SiO2-coated Cu@CuO composite particles" with "ordinary CuO particles". All other steps and parameters are the same, and will not be repeated in this comparative example. Finally, an antibacterial silicone material is obtained.

[0030] Comparative Example 3: Compared with Example 1, this comparative example modifies the silicone rubber matrix by directly using unmodified methyl vinyl silicone rubber. All other steps and parameters are the same, and will not be repeated here. The final product is an antibacterial silicone material.

[0031] Comparative Example 4: Compared with Example 1, this comparative example uses a single vulcanizing agent, dicumyl peroxide, instead of a compound vulcanizing agent. All other steps and parameters are the same, and will not be repeated here. The final product is an antibacterial silicone material.

[0032] Comparative Example 5: Compared with the examples, this comparative example uses polyethylene glycol with a number average molecular weight of 5000 to replace the polyether-modified polysiloxane dispersant. All other steps and parameters are the same, and will not be repeated in this comparative example. Finally, an antibacterial silicone material is obtained.

[0033] Performance testing: 1. Antibacterial performance test Reference standard: GB / T31402-2015 Test strains: Escherichia coli (ATCC25922), Staphylococcus aureus (ATCC6538) Test procedure: Cut the sample into 25mm × 25mm squares, sterilize with ultraviolet light, and then mix with bacterial suspension (concentration 1 × 10⁻⁶). 6The samples were cultured in contact with the plate count method for 24 hours (CFU / mL) to calculate the antibacterial rate. At the same time, the samples were subjected to 50 cycles of friction test (load 5N, friction distance 10cm / cycle), and the above steps were repeated to test the antibacterial rate after the cycle.

[0034] 2. Mechanical property testing Reference standard: GB / T528-2009 Testing equipment: Universal testing machine (model CMT6104, MTES Industrial Systems Co., Ltd.) Test procedure: Prepare the sample as a dumbbell-shaped No. 1 specimen, tensile speed 500 mm / min, and test tensile strength and elongation at break; at the same time, perform hot air aging test (100℃, 72h) according to GB / T3512-2014, and test the tensile strength retention rate after aging.

[0035] 3. Dispersion stability test Test equipment: Scanning electron microscope (SEM, model SU8010, Hitachi High Technology Co., Ltd.) Test procedure: Freeze the sample to break it into brittle fragments, sputter-coated it with gold, observe the microstructure of the cross section, and count the percentage of agglomerated particles (particle size > 500 nm) in the field of view.

[0036] 4. Antibacterial durability test Test method: Immerse the sample in deionized water (37℃, 30 days), take samples periodically to test the antibacterial rate of E. coli, and record the time when the antibacterial rate drops below 90%.

[0037] The results are shown in Tables 1-3 below: Table 1 Summary of performance test data for Examples 1-3

[0038] Table 2 Summary of performance test data for Example 4 and Comparative Examples 1-2

[0039] Table 3 Summary of performance test data for Comparative Examples 3-5

[0040] Data Analysis: 1. Antibacterial Performance Analysis: The antibacterial performance of Examples 1-4 of this invention is excellent. The initial antibacterial rate against Escherichia coli and Staphylococcus aureus both exceed 99.5%, and it remains above 99% after 50 cycles, with antibacterial durability exceeding 180 days. This is attributed to the core-shell structure design of the SiO2-coated Cu@CuO composite particles: the core Cu@CuO continuously releases Cu 2+The outer shell SiO2 layer enables the slow release of antibacterial components, while amino grafting modification ensures that the particles are evenly dispersed in the matrix, avoiding antibacterial dead zones. In contrast, Comparative Example 1, which did not add antibacterial particles, had an antibacterial rate of only about 14%, which was completely ineffective in terms of practical antibacterial effect, proving that antibacterial particles are the core source of the antibacterial performance of this invention. Comparative Example 2 used ordinary CuO particles, which had a high initial antibacterial rate, but the antibacterial rate dropped to 95.3% after repeated use, and the durability was only 90 days. The reason is that ordinary CuO particles lack SiO2 coating protection, are easily corroded and lost, and have severe agglomeration in the matrix (agglomeration rate of 12.5%), resulting in unstable antibacterial effect; Comparative Example 3 did not modify the silicone rubber matrix with amino, resulting in poor compatibility between the antibacterial particles and the matrix, with an agglomeration rate of 10.8%, which not only affected the uniformity of antibacterial action but also reduced the antibacterial durability to 105 days; Comparative Example 5 used ordinary polyethylene glycol instead of the special dispersant, resulting in poor dispersion of antibacterial particles (agglomeration rate of 11.2%) and an antibacterial durability of only 110 days, indicating that polyether-modified polysiloxane dispersant is crucial for improving antibacterial stability.

[0041] 2. Mechanical property analysis: The tensile strength of Examples 1-4 of the present invention is all above 8.6 MPa, the elongation at break is more than 520%, and the tensile strength retention rate after heat aging is more than 92%, which shows excellent mechanical properties and aging resistance. This is because: the amino-modified silicone rubber matrix and the antibacterial particles have a tight interface, reducing stress concentration; the compounded vulcanizing agent (dicumyl peroxide and triallyl isocyanurate 4:1) optimizes the crosslinking structure and improves the mechanical stability of the material; while Comparative Example 4 uses a single vulcanizing agent, resulting in uneven crosslinking density, a tensile strength of only 7.0 MPa, an elongation at break of 460%, and a retention rate of 80% after heat aging, proving that the compounded vulcanizing agent can effectively balance the crosslinking quality and mechanical properties of the material; Comparative Examples 2, 3, and 5 suffer from poor dispersion of antibacterial particles or insufficient interfacial compatibility, leading to a decline in mechanical properties, with tensile strengths all below 8.0 MPa, elongation at break below 500%, and significantly worse aging resistance (heat aging retention rate ≤87%), further illustrating the key influence of the synergistic effect of raw material modification, additive selection, and process design on mechanical properties in this invention.

[0042] 3. Dispersion Stability Analysis: The agglomeration rate of antibacterial particles in Examples 1-4 of this invention was all less than 3.5%, indicating that the amino-modified silicone rubber matrix, polyether-modified polysiloxane dispersant, and surface grafting modification of the antibacterial particles formed a synergistic dispersion effect: the amino groups in the matrix and the amino groups on the particle surface formed hydrogen bonds, and the dispersant prevented particle agglomeration through steric hindrance, ensuring the uniform distribution of particles in the matrix. In contrast, the agglomeration rate of Comparative Examples 2, 3, and 5 all exceeded 10%. Among them, Comparative Example 2 had the most severe agglomeration due to the lack of SiO2 coating and grafting modification, resulting in strong interparticle forces. Comparative Example 3 had weak interfacial bonding due to the lack of amino modification in the matrix, making particle aggregation easy. Comparative Example 5 had poor dispersant compatibility and could not effectively exert its dispersion effect. All of these findings verify the rationality of the dispersion system design of this invention.

[0043] This invention achieves simultaneous optimization of antibacterial properties, mechanical properties, and dispersion stability through the synergistic design of an amino-modified silicone rubber matrix, SiO2-coated Cu@CuO composite antibacterial particles, a specialized dispersant, and a compounded vulcanizing agent, along with a precisely controlled preparation process. Test data from various comparative examples fully demonstrate that the core technical features of this invention (raw material modification, core-shell structured antibacterial particles, and compounded additives) are key to solving problems such as poor antibacterial agent dispersion, insufficient durability, and impaired mechanical properties in existing technologies, significantly enhancing the overall practical value of antibacterial silicone materials.

[0044] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of the invention is limited to these examples; within the framework of the invention, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of the different aspects of the invention as described above, which are not provided in detail for the sake of brevity.

[0045] This invention is intended to cover all such substitutions, modifications, and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. An antibacterial silicone material and its preparation method, characterized in that, The antibacterial silicone material is prepared from the following raw materials in parts by weight: 100 parts of amino-modified silicone rubber matrix, 10-18 parts of SiO2-coated Cu@CuO composite particles, 0.6-1.2 parts of polyether-modified polysiloxane dispersant, and 1.0-1.6 parts of vulcanizing agent; The amino-modified silicone rubber matrix is ​​formed by modifying methyl vinyl silicone rubber with γ-aminopropyltriethoxysilane, with an amino grafting rate of 3.0-4.5 μmol / cm² and a surface hydroxyl conversion rate of ≥80%. The SiO2-coated Cu@CuO composite particles have a core-shell structure. The core is Cu@CuO, in which the mass ratio of Cu to CuO is 1:3 and the particle size is 60-160nm. The outer shell is a SiO2 coating layer with a thickness of 10-20nm.

2. The antibacterial silicone material according to claim 1, characterized in that, The preparation process of the SiO2-coated Cu@CuO composite particles is as follows: Step P1. Mix glucose with CuSO4 and reduce CuSO4 with glucose to generate Cu nanoparticles; Step P2. Mix Cu nanoparticles with NaOH and oxidize them with NaOH to form a Cu@CuO core; Step P3. Coating the Cu@CuO core using the tetraethyl orthosilicate sol-gel method; Step P4. The coated particles are modified by γ-aminopropyltriethoxysilane grafting to obtain SiO2-coated Cu@CuO composite particles; The mass ratio of tetraethyl orthosilicate to Cu@CuO is 1:5-7; The SiO2 coating has a pore size of 2-5 nm.

3. The antibacterial silicone material according to claim 1, characterized in that, The preparation process of Cu@CuO core in step P2 is as follows: 0.1 mol / L copper sulfate solution and glucose solution are mixed, with a molar ratio of glucose solution to CuSO4 of 1:

1. The mixture is stirred at 60°C for 2 h to generate Cu nanoparticles. Then, the temperature is raised to 80°C, and 0.05 mol / L sodium hydroxide solution is added dropwise at a rate of 1 mL / min. After the addition is complete, the mixture is reacted for 3 h to obtain Cu@CuO core. The particle size of Cu@CuO core is 60-160 nm.

4. The antibacterial silicone material according to claim 1, characterized in that, The coating process described in step P3 is as follows: the Cu@CuO core is dispersed in an ethanol-water mixture with a volume ratio of ethanol to water of 4:

1. Then, tetraethyl orthosilicate is added with a mass ratio of tetraethyl orthosilicate to Cu@CuO of 1:5-7. The pH of the system is adjusted to 8.0 with ammonia. The mixture is stirred at 40-50°C for 5-7 hours. After the reaction, a SiO2 coating layer is formed with a thickness of 10-20 nm and a porosity of 15%-25%.

5. The antibacterial silicone material according to claim 1, characterized in that, The preparation process of the amino-modified silicone rubber matrix is ​​as follows: Methyl vinyl silicone rubber was immersed in an ethanol-water mixture of 6-8 wt% γ-aminopropyltriethoxysilane, wherein the vinyl content of the methyl vinyl silicone rubber was 0.2-0.4 wt%, and the volume ratio of ethanol to water in the ethanol-water mixture was 9:

1. The reaction was carried out at 55-65℃ with shaking at 150 rpm for 4-6 hours. After the reaction, the rubber was washed three times with deionized water and then vacuum dried at 60℃ for 8 hours to obtain an amino-modified silicone rubber matrix.

6. The antibacterial silicone material according to claim 1, characterized in that, The polyether-modified polysiloxane dispersant has a number average molecular weight of 4000-6000, and the polyether segment in the polyether-modified polysiloxane dispersant is an ethylene oxide segment, with the ethylene oxide segment accounting for 35-45 wt%.

7. The antibacterial silicone material according to claim 1, characterized in that, The vulcanizing agent is a compound of dicumyl peroxide and triallyl isocyanurate in a mass ratio of 4:

1.

8. The method for preparing the antibacterial silicone material according to any one of claims 1-7, characterized in that, Includes the following steps: Step S1. Preparation of amino-modified silicone rubber matrix; Step S2. Preparation of SiO2-coated Cu@CuO composite particles; Step S3. Preparation of composite rubber compound: The amino-modified silicone rubber matrix is ​​added to a two-roll mill for mixing. The rolling temperature of the two-roll mill is 45-55℃ and the rolling gap is 0.8-1.2mm. The mixing time is 4-6min. Then, a dispersant is added and mixing is continued for 2-3min. Then, SiO2-coated Cu@CuO composite particles are added in 2-3 batches, and mixing is carried out for 4-5min after each addition of SiO2-coated Cu@CuO composite particles. Finally, a vulcanizing agent is added and mixing is carried out for 6-8min to obtain the composite rubber compound. Step S4. Vulcanization molding: The composite rubber compound is first pre-pressed at a temperature of 70-80℃ and a pressure of 2-4MPa for 8-12 minutes, and then vulcanized at a temperature of 140-150℃ and a pressure of 6-8MPa for 20-25 minutes; after vulcanization, it is cooled and demolded to obtain antibacterial silicone material.

9. The method for preparing the antibacterial silicone material according to claim 8, characterized in that, The mixing parameters of the open mill mentioned in step S3 are: roll temperature fluctuation ≤ ±2℃, roll gap fluctuation ≤ ±0.1mm.

10. The method for preparing the antibacterial silicone material according to claim 8, characterized in that, The heating rate during vulcanization in step S4 is 8-12℃ / min, the cooling rate is 4-6℃ / min, and the pressure fluctuation during vulcanization is ≤±0.2MPa.

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