An antibacterial silicone rubber and its preparation method

Abstract

This invention discloses an antibacterial silicone rubber and its preparation method, belonging to the field of rubber materials technology. By weight, it comprises the following components: 80-100 parts of silicone rubber matrix, 10-20 parts of nano-composite antibacterial agent, 1-3 parts of crosslinking agent, 0.5-2 parts of stabilizer, and 5-15 parts of filler. The nano-composite antibacterial agent in this invention combines the synergistic antibacterial properties of nano-silver and quaternary ammonium salt, the reinforcing and toughening properties of SiO2, and long-lasting resistance to precipitation, enabling the prepared silicone rubber to be widely used in fields such as medical, food, and electronics where high antibacterial durability is required.

Description

Technical Field

[0001] This invention relates to the field of rubber materials technology, specifically to an antibacterial silicone rubber and its preparation method. Background Technology

[0002] Silicone rubber is widely used in electronics, medical, and food processing due to its excellent resistance to high and low temperatures, electrical insulation, and chemical stability. However, traditional silicone rubber materials are prone to bacterial growth on their surfaces, leading to a decline in material performance and even health problems. To address this issue, various methods for preparing antibacterial silicone rubber have been proposed, such as adding antibacterial agents and surface modification. However, these methods have some drawbacks. For example, antibacterial agents may pollute the environment and are prone to precipitation under high temperature and humidity conditions, resulting in a decrease in antibacterial efficacy. In addition, large amounts of antibacterial agents may negatively affect the mechanical properties of silicone rubber; surface modification methods have poor antibacterial durability, and the modified layer is prone to wear or peeling off during long-term use, leading to a decrease in antibacterial efficacy. Therefore, developing an environmentally friendly silicone rubber material with long-lasting antibacterial properties is of significant practical importance. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to overcome the deficiencies and defects mentioned in the background art above, and to provide an antibacterial silicone rubber and its preparation method. The silicone rubber has good antibacterial properties, biocompatibility and durability, and the preparation method is simple, environmentally friendly and suitable for large-scale production.

[0004] The technical solution of this invention is implemented as follows:

[0005] This invention provides an antibacterial silicone rubber, which is composed of the following raw materials in parts by weight: 80-100 parts of silicone rubber matrix, 10-20 parts of nano-composite antibacterial agent, 1-3 parts of crosslinking agent, 0.5-2 parts of stabilizer, and 5-15 parts of filler.

[0006] As a further improvement of the present invention, the nanocomposite antibacterial agent is prepared by the following method:

[0007] S1. Preparation of nano-flower-like SiO2 spheres: Tetraethyl orthosilicate, cyclohexane, and pentanol were mixed, and an aqueous solution of emulsifier and urea was added. The mixture was stirred at 12,000-20,000 rpm for 10-20 min at room temperature, then heated to 70-80℃ and stirred at 200-300 rpm for 4-8 h. The mixture was then centrifuged, washed, spray-dried, and calcined at 400-600℃ for 1-2 h to obtain nano-flower-like SiO2 spheres.

[0008] Preparation of S2.SiO2@Ag: Nanoflower-shaped SiO2 spheres and AgNO3 were dispersed in ethanol, n-butylamine was added, and the mixture was stirred at 50-60℃ for 30-60 min. After centrifugation and washing, the mixture was spray-dried to obtain SiO2@Ag particles.

[0009] S3. Quaternization modification: SiO2@Ag particles were dispersed in ethanol, and 3-chloropropyltrimethoxysilane and γ-methacryloyloxypropyltrimethoxysilane were added. After stirring at room temperature for 6-12 hours, 30wt% trimethylamine aqueous solution was added, and the reaction was carried out at 20-50℃ for 4-12 hours. After centrifugation and washing, the nanocomposite antibacterial agent was obtained.

[0010] As a further improvement of the present invention, in step S1, the emulsifier is selected from one of hexadecylpyridine bromide, hexadecyltrimethylammonium bromide, and hexadecyltrimethylammonium chloride.

[0011] As a further improvement of the present invention, in step S1, the mass ratio of tetraethyl orthosilicate, cyclohexane, pentanol, emulsifier, urea and water is 1:(10-12):(0.5-1):(0.4-0.5):(0.3-0.5):(12-15).

[0012] As a further improvement of the present invention, in step S2, the mass ratio of the nano-flower-like SiO2 spheres, AgNO3, ethanol, and n-butylamine is 1:(0.5-1):(50-100):(0.4-0.6).

[0013] As a further improvement of the present invention, in step S3, the mass ratio of the SiO2@Ag particles, ethanol, 3-chloropropyltrimethoxysilane, γ-methacryloyloxypropyltrimethoxysilane, and trimethylamine aqueous solution is 1:(50-100):(0.2-0.5):(0.05-0.1):(1-5).

[0014] As a further improvement of the present invention, the silicone rubber matrix is ​​methyl vinyl silicone rubber with a molecular weight of 500,000-600,000 and a vinyl content of 0.1-0.3 mol%; the crosslinking agent is a peroxide crosslinking agent; the stabilizer is an antioxidant; and the filler is calcium carbonate or talc.

[0015] As a further improvement of the present invention, the peroxide crosslinking agent is selected from one of dicumyl peroxide, benzoyl peroxide, and di-tert-butyl peroxide.

[0016] As a further improvement of the present invention, the antioxidant is selected from one of N-phenyl-2-naphthylamine, 4,4'-disec-butyldiphenylamine, N,N'-diphenyl-p-phenylenediamine, and N,N'-disec-butyl-p-phenylenediamine.

[0017] This invention further protects a method for preparing the above-mentioned antibacterial silicone rubber, comprising the following steps:

[0018] According to the formula, the silicone rubber matrix, nano-composite antibacterial agent, crosslinking agent, stabilizer, and filler are mixed evenly to obtain a mixture; the mixture is then internally mixed in a mixer at a temperature of 120-160℃ for 10-20 minutes; the internally mixed mixture is then open-milled on a rolling mill at a temperature of 100-140℃ for 5-15 minutes; the open-milled mixture is then vulcanized at a temperature of 140-180℃ for 10-30 minutes to obtain antibacterial silicone rubber.

[0019] The present invention has the following beneficial effects:

[0020] 1. Synergistic Antibacterial Properties: The antibacterial silicone rubber of this invention uses a nano-composite antibacterial agent, with silicon dioxide as the main component, which has excellent antibacterial properties and is environmentally friendly. Nano-silver (Ag) and quaternary ammonium salt have a synergistic antibacterial effect, which can significantly improve the antibacterial effect while reducing the impact on the environment.

[0021] 2. Improved Mechanical Properties: The main component of the nanocomposite antibacterial agent is silicon dioxide, which can not only act as an antibacterial agent but also as a reinforcing agent, improving the mechanical properties of silicone rubber. By optimizing the ratio of the silicone rubber matrix to other additives, the prepared silicone rubber exhibits excellent mechanical properties, including tensile strength, elongation at break, and hardness.

[0022] 3. Enhanced Interfacial Connectivity: Using micelles formed by the self-assembly of emulsifiers as templates, urea induces the hydrolysis and condensation of the silicon precursor within the available space between the self-assembled template molecules, forming a flower-like structure. Calcination removes the emulsifier template, yielding flower-shaped silica spheres. The subsequently prepared nanocomposite antibacterial agent retains this flower-like structure, with petals that can insert into the silicone rubber matrix, forming a tenon-and-mortise structure that enhances the interfacial connectivity between the two. This structure effectively improves the mechanical and antibacterial properties of silicone rubber.

[0023] 4. Chemical Bonding: In the process of preparing nanocomposite antibacterial agents through quaternary ammonium salt modification, γ-methacryloyloxypropyltrimethoxysilane, a silane coupling agent containing double bonds, was added. This ensures that the surface of the silica spheres contains both quaternary ammonium salt groups and double bond groups. These double bond groups can react with the double bonds on the silicone rubber during subsequent preparation, resulting in a tight chemical bond between the antibacterial agent and the silicone rubber matrix, further improving antibacterial and mechanical properties. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a TEM image of the nanoflower-like SiO2 spheres prepared in Example 1 of the present invention.

[0026] Figure 2 This is a TEM image of the nanocomposite antibacterial agent prepared in Example 1 of the present invention. Detailed Implementation

[0027] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] Example 1

[0029] An antibacterial silicone rubber comprises the following raw materials: 80g of silicone rubber matrix, 10g of nano-composite antibacterial agent, 1g of crosslinking agent, 0.5g of stabilizer, and 5g of filler;

[0030] The silicone rubber matrix is ​​methyl vinyl silicone rubber (molecular weight of 500,000, vinyl content of 0.1 mol%), the crosslinking agent is dicumyl peroxide, the stabilizer is N-phenyl-2-naphthylamine, and the filler is calcium carbonate.

[0031] A method for preparing antibacterial silicone rubber includes the following steps:

[0032] S1. Preparation of nanoflower-like SiO2 spheres: 10g tetraethyl orthosilicate, 100g cyclohexane, and 5g pentanol were mixed, and 130g of an aqueous solution containing 4g hexadecylpyridine bromide and 3g urea was added. The mixture was stirred at 12000rpm for 10min at room temperature, heated to 70℃, stirred at 200rpm for 4h, centrifuged and washed, spray-dried, and calcined at 400℃ for 2h to obtain nanoflower-like SiO2 spheres. Figure 1 The TEM image shows the nanoflower-like structure of the SiO2 spheres.

[0033] Preparation of S2.SiO2@Ag: 10g of nano-flower-shaped SiO2 spheres and 5g of AgNO3 were dispersed in 500g of ethanol, 4g of n-butylamine was added, and the mixture was stirred at 50℃ for 30min. After centrifugation and washing, the mixture was spray-dried to obtain SiO2@Ag particles. Figure 2 The TEM image shows SiO2@Ag particles, clearly revealing numerous nanoscale Ag particles growing on the surface of the nanoflower-like SiO2 spheres.

[0034] S3. Quaternization modification: 10g SiO2@Ag particles were dispersed in 500g ethanol, 2g 3-chloropropyltrimethoxysilane and 0.5g γ-methacryloyloxypropyltrimethoxysilane were added, and the mixture was stirred at room temperature for 6h. Then, 10g 30wt% trimethylamine aqueous solution was added, and the mixture was reacted at 50℃ for 4h. After centrifugation and washing, the mixture was spray-dried to obtain the nanocomposite antibacterial agent.

[0035] S4. According to the formula, mix the silicone rubber matrix, nano-composite antibacterial agent, crosslinking agent, stabilizer, and filler evenly to obtain a mixture; mix the mixture in an internal mixer at a temperature of 120℃ for 20 minutes; mix the internally mixed mixture in a two-roll mill at a temperature of 140℃ for 10 minutes; vulcanize the two-roll mixture at a temperature of 180℃ for 10 minutes to obtain antibacterial silicone rubber.

[0036] Example 2

[0037] An antibacterial silicone rubber comprises the following raw materials: 100g silicone rubber matrix, 20g nano-composite antibacterial agent, 3g crosslinking agent, 2g stabilizer, and 15g filler;

[0038] The silicone rubber matrix is ​​methyl vinyl silicone rubber (molecular weight of 500,000, vinyl content of 0.1 mol%), the crosslinking agent is dicumyl peroxide, the stabilizer is N-phenyl-2-naphthylamine, and the filler is calcium carbonate.

[0039] A method for preparing antibacterial silicone rubber includes the following steps:

[0040] S1. Preparation of nanoflower-like SiO2 spheres: 10g tetraethyl orthosilicate, 100g cyclohexane, and 5g pentanol were mixed, and 130g of an aqueous solution containing 4g hexadecylpyridine bromide and 3g urea was added. The mixture was stirred at 12000rpm for 10min at room temperature, heated to 70℃, stirred at 200rpm for 4h, centrifuged and washed, spray-dried, and calcined at 400℃ for 2h to obtain nanoflower-like SiO2 spheres.

[0041] Preparation of S2.SiO2@Ag: 10g of nano-flower-shaped SiO2 spheres and 5g of AgNO3 were dispersed in 500g of ethanol, 4g of n-butylamine was added, and the mixture was stirred at 50℃ for 30min. After centrifugation and washing, the mixture was spray-dried to obtain SiO2@Ag particles.

[0042] S3. Quaternization modification: 10g SiO2@Ag particles were dispersed in 500g ethanol, 2g 3-chloropropyltrimethoxysilane and 0.5g γ-methacryloyloxypropyltrimethoxysilane were added, and the mixture was stirred at room temperature for 6h. Then, 10g 30wt% trimethylamine aqueous solution was added, and the mixture was reacted at 50℃ for 4h. After centrifugation and washing, the mixture was spray-dried to obtain the nanocomposite antibacterial agent.

[0043] S4. According to the formula, mix the silicone rubber matrix, nano-composite antibacterial agent, crosslinking agent, stabilizer, and filler evenly to obtain a mixture; mix the mixture in an internal mixer at a temperature of 120℃ for 20 minutes; mix the internally mixed mixture in a two-roll mill at a temperature of 140℃ for 10 minutes; vulcanize the two-roll mixture at a temperature of 180℃ for 10 minutes to obtain antibacterial silicone rubber.

[0044] Example 3

[0045] An antibacterial silicone rubber comprises the following raw materials: 90g of silicone rubber matrix, 15g of nano-composite antibacterial agent, 2g of crosslinking agent, 1.2g of stabilizer, and 10g of filler;

[0046] The silicone rubber matrix is ​​methyl vinyl silicone rubber (molecular weight of 500,000, vinyl content of 0.1 mol%), the crosslinking agent is dicumyl peroxide, the stabilizer is N-phenyl-2-naphthylamine, and the filler is calcium carbonate.

[0047] A method for preparing antibacterial silicone rubber includes the following steps:

[0048] S1. Preparation of nanoflower-like SiO2 spheres: 10g tetraethyl orthosilicate, 100g cyclohexane, and 5g pentanol were mixed, and 130g of an aqueous solution containing 4g hexadecylpyridine bromide and 3g urea was added. The mixture was stirred at 12000rpm for 10min at room temperature, heated to 70℃, stirred at 200rpm for 4h, centrifuged and washed, spray-dried, and calcined at 400℃ for 2h to obtain nanoflower-like SiO2 spheres.

[0049] Preparation of S2.SiO2@Ag: 10g of nano-flower-shaped SiO2 spheres and 5g of AgNO3 were dispersed in 500g of ethanol, 4g of n-butylamine was added, and the mixture was stirred at 50℃ for 30min. After centrifugation and washing, the mixture was spray-dried to obtain SiO2@Ag particles.

[0050] S3. Quaternization modification: 10g SiO2@Ag particles were dispersed in 500g ethanol, 2g 3-chloropropyltrimethoxysilane and 0.5g γ-methacryloyloxypropyltrimethoxysilane were added, and the mixture was stirred at room temperature for 6h. Then, 10g 30wt% trimethylamine aqueous solution was added, and the mixture was reacted at 50℃ for 4h. After centrifugation and washing, the mixture was spray-dried to obtain the nanocomposite antibacterial agent.

[0051] S4. According to the formula, mix the silicone rubber matrix, nano-composite antibacterial agent, crosslinking agent, stabilizer, and filler evenly to obtain a mixture; mix the mixture in an internal mixer at a temperature of 120℃ for 20 minutes; mix the internally mixed mixture in a two-roll mill at a temperature of 140℃ for 10 minutes; vulcanize the two-roll mixture at a temperature of 180℃ for 10 minutes to obtain antibacterial silicone rubber.

[0052] Example 4

[0053] An antibacterial silicone rubber comprises the following raw materials: 80g of silicone rubber matrix, 10g of nano-composite antibacterial agent, 1g of crosslinking agent, 0.5g of stabilizer, and 5g of filler;

[0054] The silicone rubber matrix is ​​methyl vinyl silicone rubber (molecular weight of 600,000, vinyl content of 0.2 mol%), the crosslinking agent is dicumyl peroxide, the stabilizer is N-phenyl-2-naphthylamine, and the filler is calcium carbonate.

[0055] A method for preparing antibacterial silicone rubber includes the following steps:

[0056] S1. Preparation of nanoflower-like SiO2 spheres: 10g tetraethyl orthosilicate, 100g cyclohexane, and 5g pentanol were mixed, and 130g of an aqueous solution containing 4g hexadecyltrimethylammonium bromide and 3g urea was added. The mixture was stirred at 20,000 rpm for 10 min at room temperature, then heated to 70℃ and stirred at 300 rpm for 8 h. After centrifugation and washing, the mixture was spray-dried and calcined at 600℃ for 1 h to obtain nanoflower-like SiO2 spheres.

[0057] Preparation of S2.SiO2@Ag: 10g of nano-flower-shaped SiO2 spheres and 5g of AgNO3 were dispersed in 500g of ethanol, 4g of n-butylamine was added, and the mixture was stirred at 50℃ for 30min. After centrifugation and washing, the mixture was spray-dried to obtain SiO2@Ag particles.

[0058] S3. Quaternization modification: 10g SiO2@Ag particles were dispersed in 500g ethanol, 2g 3-chloropropyltrimethoxysilane and 0.5g γ-methacryloyloxypropyltrimethoxysilane were added, and the mixture was stirred at room temperature for 6h. Then, 10g 30wt% trimethylamine aqueous solution was added, and the mixture was reacted at 50℃ for 4h. After centrifugation and washing, the mixture was spray-dried to obtain the nanocomposite antibacterial agent.

[0059] S4. According to the formula, mix the silicone rubber matrix, nano-composite antibacterial agent, crosslinking agent, stabilizer, and filler evenly to obtain a mixture; mix the mixture in an internal mixer at a temperature of 120℃ for 20 minutes; mix the internally mixed mixture in a two-roll mill at a temperature of 140℃ for 10 minutes; vulcanize the two-roll mixture at a temperature of 180℃ for 10 minutes to obtain antibacterial silicone rubber.

[0060] Comparative Example 1

[0061] The only difference between this comparative example and Example 1 is that hexadecylpyridine bromide was not added in step S1, as detailed below:

[0062] An antibacterial silicone rubber comprises the following raw materials: 80g of silicone rubber matrix, 10g of nano-composite antibacterial agent, 1g of crosslinking agent, 0.5g of stabilizer, and 5g of filler;

[0063] The silicone rubber matrix is ​​methyl vinyl silicone rubber (molecular weight of 500,000, vinyl content of 0.1 mol%), the crosslinking agent is dicumyl peroxide, the stabilizer is N-phenyl-2-naphthylamine, and the filler is calcium carbonate.

[0064] A method for preparing antibacterial silicone rubber includes the following steps:

[0065] S1. Preparation of nano-flower-like SiO2 spheres: 10g tetraethyl orthosilicate, 100g cyclohexane, and 5g pentanol were mixed and 130g of an aqueous solution containing 3g urea was added. The mixture was stirred at 12000rpm for 10min at room temperature, heated to 70℃, stirred at 200rpm for 4h, centrifuged and washed, spray-dried, and calcined at 400℃ for 2h to obtain nano-flower-like SiO2 spheres.

[0066] Preparation of S2.SiO2@Ag: 10g of nano-flower-shaped SiO2 spheres and 5g of AgNO3 were dispersed in 500g of ethanol, 4g of n-butylamine was added, and the mixture was stirred at 50℃ for 30min. After centrifugation and washing, the mixture was spray-dried to obtain SiO2@Ag particles.

[0067] S3. Quaternization modification: 10g SiO2@Ag particles were dispersed in 500g ethanol, 2g 3-chloropropyltrimethoxysilane and 0.5g γ-methacryloyloxypropyltrimethoxysilane were added, and the mixture was stirred at room temperature for 6h. Then, 10g 30wt% trimethylamine aqueous solution was added, and the mixture was reacted at 50℃ for 4h. After centrifugation and washing, the mixture was spray-dried to obtain the nanocomposite antibacterial agent.

[0068] S4. According to the formula, mix the silicone rubber matrix, nano-composite antibacterial agent, crosslinking agent, stabilizer, and filler evenly to obtain a mixture; mix the mixture in an internal mixer at a temperature of 120℃ for 20 minutes; mix the internally mixed mixture in a two-roll mill at a temperature of 140℃ for 10 minutes; vulcanize the two-roll mixture at a temperature of 180℃ for 10 minutes to obtain antibacterial silicone rubber.

[0069] Comparative Example 2

[0070] The only difference between this comparative example and Example 1 is that γ-methacryloyloxypropyltrimethoxysilane is not added in step S3, as detailed below:

[0071] An antibacterial silicone rubber comprises the following raw materials: 80g of silicone rubber matrix, 10g of nano-composite antibacterial agent, 1g of crosslinking agent, 0.5g of stabilizer, and 5g of filler;

[0072] The silicone rubber matrix is ​​methyl vinyl silicone rubber (molecular weight of 500,000, vinyl content of 0.1 mol%), the crosslinking agent is dicumyl peroxide, the stabilizer is N-phenyl-2-naphthylamine, and the filler is calcium carbonate.

[0073] A method for preparing antibacterial silicone rubber includes the following steps:

[0074] S1. Preparation of nanoflower-like SiO2 spheres: 10g tetraethyl orthosilicate, 100g cyclohexane, and 5g pentanol were mixed, and 130g of an aqueous solution containing 4g hexadecylpyridine bromide and 3g urea was added. The mixture was stirred at 12000rpm for 10min at room temperature, heated to 70℃, stirred at 200rpm for 4h, centrifuged and washed, spray-dried, and calcined at 400℃ for 2h to obtain nanoflower-like SiO2 spheres.

[0075] Preparation of S2.SiO2@Ag: 10g of nano-flower-shaped SiO2 spheres and 5g of AgNO3 were dispersed in 500g of ethanol, 4g of n-butylamine was added, and the mixture was stirred at 50℃ for 30min. After centrifugation and washing, the mixture was spray-dried to obtain SiO2@Ag particles.

[0076] S3. Quaternization modification: 10g SiO2@Ag particles were dispersed in 500g ethanol, 2g 3-chloropropyltrimethoxysilane was added, and the mixture was stirred at room temperature for 6h. Then, 10g 30wt% trimethylamine aqueous solution was added, and the mixture was reacted at 50℃ for 4h. After centrifugation and washing, the mixture was spray-dried to obtain a nanocomposite antibacterial agent.

[0077] S4. According to the formula, mix the silicone rubber matrix, nano-composite antibacterial agent, crosslinking agent, stabilizer, and filler evenly to obtain a mixture; mix the mixture in an internal mixer at a temperature of 120℃ for 20 minutes; mix the internally mixed mixture in a two-roll mill at a temperature of 140℃ for 10 minutes; vulcanize the two-roll mixture at a temperature of 180℃ for 10 minutes to obtain antibacterial silicone rubber.

[0078] Comparative Example 3

[0079] The only difference between this comparative example and Example 1 is that Ag particles are not introduced into the nano-flower-like SiO2 spheres, as detailed below:

[0080] An antibacterial silicone rubber comprises the following raw materials: 80g of silicone rubber matrix, 10g of nano-composite antibacterial agent, 1g of crosslinking agent, 0.5g of stabilizer, and 5g of filler;

[0081] The silicone rubber matrix is ​​methyl vinyl silicone rubber (molecular weight of 500,000, vinyl content of 0.1 mol%), the crosslinking agent is dicumyl peroxide, the stabilizer is N-phenyl-2-naphthylamine, and the filler is calcium carbonate.

[0082] A method for preparing antibacterial silicone rubber includes the following steps:

[0083] S1. Preparation of nanoflower-like SiO2 spheres: 10g tetraethyl orthosilicate, 100g cyclohexane, and 5g pentanol were mixed, and 130g of an aqueous solution containing 4g hexadecylpyridine bromide and 3g urea was added. The mixture was stirred at 12000rpm for 10min at room temperature, heated to 70℃, stirred at 200rpm for 4h, centrifuged and washed, spray-dried, and calcined at 400℃ for 2h to obtain nanoflower-like SiO2 spheres.

[0084] S2. Quaternization modification: 10g of nano-flower-like SiO2 spheres were dispersed in 500g of ethanol, 2g of 3-chloropropyltrimethoxysilane and 0.5g of γ-methacryloyloxypropyltrimethoxysilane were added, and the mixture was stirred at room temperature for 6h. Then, 10g of 30wt% trimethylamine aqueous solution was added, and the mixture was reacted at 50℃ for 4h. After centrifugation and washing, the mixture was spray-dried to obtain a nano-composite antibacterial agent.

[0085] S3. According to the formula, mix the silicone rubber matrix, nano-composite antibacterial agent, crosslinking agent, stabilizer, and filler evenly to obtain a mixture; mix the mixture in an internal mixer at a temperature of 120℃ for 20 minutes; mix the internally mixed mixture in a two-roll mill at a temperature of 140℃ for 10 minutes; vulcanize the two-roll mixture at a temperature of 180℃ for 10 minutes to obtain antibacterial silicone rubber.

[0086] Comparative Example 4

[0087] The only difference between this comparative example and Example 1 is that the nanocomposite antibacterial agent is not modified with quaternary ammonium salts during preparation, as detailed below:

[0088] An antibacterial silicone rubber comprises the following raw materials: 80g of silicone rubber matrix, 10g of nano-composite antibacterial agent, 1g of crosslinking agent, 0.5g of stabilizer, and 5g of filler;

[0089] The silicone rubber matrix is ​​methyl vinyl silicone rubber (molecular weight of 500,000, vinyl content of 0.1 mol%), the crosslinking agent is dicumyl peroxide, the stabilizer is N-phenyl-2-naphthylamine, and the filler is calcium carbonate.

[0090] A method for preparing antibacterial silicone rubber includes the following steps:

[0091] S1. Preparation of nanoflower-like SiO2 spheres: 10g tetraethyl orthosilicate, 100g cyclohexane, and 5g pentanol were mixed, and 130g of an aqueous solution containing 4g hexadecylpyridine bromide and 3g urea was added. The mixture was stirred at 12000rpm for 10min at room temperature, heated to 70℃, stirred at 200rpm for 4h, centrifuged and washed, spray-dried, and calcined at 400℃ for 2h to obtain nanoflower-like SiO2 spheres.

[0092] Preparation of S2.SiO2@Ag: 10g of nano-flower-shaped SiO2 spheres and 5g of AgNO3 were dispersed in 500g of ethanol, 4g of n-butylamine was added, and the mixture was stirred and reacted at 50℃ for 30min. After centrifugation and washing, the mixture was spray-dried to obtain SiO2@Ag particles, i.e., nano-composite antibacterial agent.

[0093] S3. According to the formula, mix the silicone rubber matrix, nano-composite antibacterial agent, crosslinking agent, stabilizer, and filler evenly to obtain a mixture; mix the mixture in an internal mixer at a temperature of 120℃ for 20 minutes; mix the internally mixed mixture in a two-roll mill at a temperature of 140℃ for 10 minutes; vulcanize the two-roll mixture at a temperature of 180℃ for 10 minutes to obtain antibacterial silicone rubber.

[0094] Test Example 1: Mechanical Property Test

[0095] Mechanical properties were tested in accordance with GB / T 528-2009, using type 1 dumbbell-shaped specimens (narrow section 25mm×6mm, thickness 2mm), tensile rate 500mm·min1, temperature 25℃, relative humidity 50%RH.

[0096] Test Example 2: Antibacterial Performance Test

[0097] Referring to GB / T 20944.3-2008, Escherichia coli (ATCC 25922) and Staphylococcus aureus (ATCC 6538) were selected, with a bacterial concentration of 1.0 × 10⁻⁶. 5 CFU·mL1, cultured at 37℃ for 24 hours with a film, and the average inhibition rate of the two bacteria was taken as the "inhibition rate" report value.

[0098] Test Example 3: Accelerated Aging Test with Hot Water

[0099] According to ASTM D471-16, the sample was completely immersed in deionized water at 85°C for 168 hours, then removed and air-dried at 23°C for 24 hours before testing.

[0100] Test Example 4: Antibacterial Durability Test

[0101] The antibacterial rate of the samples after hot water aging was re-determined under the conditions of Test Example 2.

[0102] The antibacterial silicone rubbers prepared in Examples 1-4 and Comparative Examples 1-4 of the present invention were subjected to performance tests according to Test Examples 1-4, and the results are shown in Table 1.

[0103] Table 1

[0104]

[0105] As shown in Table 1, the antibacterial silicone rubbers prepared in Examples 1-4 all exhibited an immediate antibacterial rate of greater than 99%, and the antibacterial rate was still greater than 95% after aging in hot water for 168 hours. This demonstrates that the "nano silver + quaternary ammonium salt" synergistic system and the chemical bonding interface are significantly superior to the comparative examples in terms of long-term antibacterial effect.

[0106] The only difference between Comparative Example 1 and Example 1 is that hexadecylpyridine bromide was not added in step S1. This resulted in the nanocomposite antibacterial agent prepared in Example 1 not having a flower-like structure, reducing the surface area of ​​the antibacterial agent, decreasing the number of Ag and quaternary ammonium salt groups that could be modified later, and consequently reducing the antibacterial effect. Furthermore, the petal structure could not form a tenon-and-mortise structure with the silicone rubber matrix, leading to a decrease in tensile strength.

[0107] The only difference between Comparative Example 2 and Example 1 is that γ-methacryloyloxypropyltrimethoxysilane is not added in step S3. The Ag and quaternary ammonium salt modification steps are still complete. Therefore, the surface of the nanocomposite antibacterial agent still retains the dual antibacterial system of Ag + quaternary ammonium salt, which can exert a bactericidal effect instantly upon contact with bacteria. The immediate antibacterial rate can be maintained at a level similar to that of the Example. However, the antibacterial rate will drop to about 72% after hot water aging. This is mainly because the nanocomposite antibacterial agent and silicone rubber cannot form a chemical bond connection, which will lead to the loss of antibacterial agent during long-term hot water aging tests.

[0108] The only difference between Comparative Example 3 and Example 1 is that Ag particles are not introduced into the nano-flower-shaped SiO2 spheres, resulting in a lack of Ag antibacterial effect and an immediate antibacterial rate of only 75.6%.

[0109] The only difference between Comparative Example 4 and Example 1 is that the nanocomposite antibacterial agent is not modified with quaternary ammonium salt during preparation, thus lacking the antibacterial effect of quaternary ammonium salt. At the same time, without the protection of the quaternary ammonium salt shell, Ag comes into direct contact with the medium, accelerating oxidation and aggregation, which leads to a deterioration in long-lasting antibacterial performance.

[0110] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An antibacterial silicone rubber, characterized in that, It is composed of the following raw materials in parts by weight: 80-100 parts silicone rubber matrix, 10-20 parts nanocomposite antibacterial agent, 1-3 parts crosslinking agent, 0.5-2 parts stabilizer, and 5-15 parts filler; the nanocomposite antibacterial agent is prepared by the following method: S1. Preparation of nano-flower-like SiO2 spheres: Tetraethyl orthosilicate, cyclohexane, and pentanol were mixed, and an aqueous solution of emulsifier and urea was added. The mixture was stirred at 12,000-20,000 rpm for 10-20 min at room temperature, then heated to 70-80℃ and stirred at 200-300 rpm for 4-8 h. The mixture was then centrifuged, washed, spray-dried, and calcined at 400-600℃ for 1-2 h to obtain nano-flower-like SiO2 spheres. S2. Preparation of SiO2@Ag: Nanoflower-shaped SiO2 spheres and AgNO3 were dispersed in ethanol, n-butylamine was added, and the mixture was stirred at 50-60℃ for 30-60 min. After centrifugation and washing, the mixture was spray-dried to obtain SiO2@Ag particles. S3. Quaternization modification: SiO2@Ag particles were dispersed in ethanol, and 3-chloropropyltrimethoxysilane and γ-methacryloyloxypropyltrimethoxysilane were added. After stirring at room temperature for 6-12 hours, 30wt% trimethylamine aqueous solution was added, and the reaction was carried out at 20-50℃ for 4-12 hours. After centrifugation and washing, the nanocomposite antibacterial agent was obtained by spray drying.

2. The antibacterial silicone rubber according to claim 1, characterized in that, In step S1, the emulsifier is selected from one of hexadecylpyridine bromide, hexadecyltrimethylammonium bromide, and hexadecyltrimethylammonium chloride.

3. The antibacterial silicone rubber according to claim 1, characterized in that, In step S1, the mass ratio of tetraethyl orthosilicate, cyclohexane, pentanol, emulsifier, urea, and water is 1:(10-12):(0.5-1):(0.4-0.5):(0.3-0.5):(12-15).

4. The antibacterial silicone rubber according to claim 1, characterized in that, In step S2, the mass ratio of the nanoflower-shaped SiO2 spheres, AgNO3, ethanol, and n-butylamine is 1:(0.5-1):(50-100):(0.4-0.6).

5. The antibacterial silicone rubber according to claim 1, characterized in that, In step S3, the mass ratio of the SiO2@Ag particles, ethanol, 3-chloropropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, and trimethylamine aqueous solution is 1:(50-100):(0.2-0.5):(0.05-0.1):(1-5).

6. The antibacterial silicone rubber according to claim 1, characterized in that, The silicone rubber matrix is ​​methyl vinyl silicone rubber with a molecular weight of 500,000-600,000 and a vinyl content of 0.1-0.3 mol%; the crosslinking agent is a peroxide crosslinking agent, the stabilizer is an antioxidant, and the filler is calcium carbonate or talc.

7. The antibacterial silicone rubber according to claim 6, characterized in that, The peroxide crosslinking agent is selected from one of dicumyl peroxide, benzoyl peroxide, and di-tert-butyl peroxide.

8. The antibacterial silicone rubber according to claim 6, characterized in that, The antioxidant is selected from one of N-phenyl-2-naphthylamine, N,N'-diphenyl-p-phenylenediamine, and N,N'-di-sec-butyl-p-phenylenediamine.

9. A method for preparing antibacterial silicone rubber according to any one of claims 1-8, characterized in that, Includes the following steps: According to the formula, the silicone rubber matrix, nano-composite antibacterial agent, crosslinking agent, stabilizer, and filler are mixed evenly to obtain a mixture; the mixture is then internally mixed in a mixer at a temperature of 120-160℃ for 10-20 minutes; the internally mixed mixture is then open-milled on a rolling mill at a temperature of 100-140℃ for 5-15 minutes; the open-milled mixture is then vulcanized at a temperature of 140-180℃ for 10-30 minutes to obtain antibacterial silicone rubber.

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