An aerogel antibacterial coating and its preparation method

Abstract

This invention relates to the field of coating technology and proposes an aerogel antibacterial coating and its preparation method. An aerogel antibacterial coating comprises the following components by weight: 35-45 parts epoxy resin, 8-12 parts quaternized SiO2 aerogel, 1-1.5 parts antibacterial agent, 15-20 parts curing agent, 2-3 parts wetting agent, 0.5-1 part defoamer, and 25-28 parts water; the antibacterial agent includes ε-polylysine. This technical solution solves the problem of poor antibacterial properties of existing aerogel coatings.

Description

Technical Field

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

[0002] Aerogels, with their extremely low density, ultra-high specific surface area, and three-dimensional porous nanostructure, are widely used in coating systems to impart functional properties such as heat insulation, lightweight, and adsorption. As an important category of functional coatings, antibacterial coatings are seeing a continuous increase in demand in fields such as construction, home furnishing, medical devices, and food processing. Combining aerogels with antibacterial functions to prepare aerogel antibacterial coatings has become a research hotspot in the coatings field.

[0003] Existing technologies have attempted to incorporate SiO2 aerogel into antibacterial coating systems, but several technical shortcomings remain in practical applications, making it difficult to balance the antibacterial and mechanical properties of the coating, thus limiting its industrial application. On one hand, unmodified SiO2 aerogels are rich in hydroxyl groups, exhibiting strong polarity and poor interfacial compatibility with organic epoxy resin matrices. This leads to agglomeration in coating systems, resulting in structural defects such as micropores and stress concentration within the coating. This not only significantly reduces the coating's tensile strength and hardness but also decreases its density, allowing external moisture and microorganisms to easily penetrate and weaken the antibacterial effect. On the other hand, existing aerogel antibacterial coatings often use a single antibacterial component, resulting in a limited antibacterial effect that fails to meet the requirements for antibacterial performance in practical applications. Summary of the Invention

[0004] This invention proposes an aerogel antibacterial coating and its preparation method, which solves the problem of poor antibacterial properties of aerogel coatings in related technologies.

[0005] The technical solution of the present invention is as follows: This invention proposes an aerogel antibacterial coating, comprising the following components by weight: 35-45 parts epoxy resin, 8-12 parts quaternized SiO2 aerogel, 1-1.5 parts antibacterial agent, 15-20 parts curing agent, 2-3 parts wetting agent, 0.5-1 part defoamer, and 25-28 parts water. The antibacterial agent includes ε-polylysine.

[0006] As a further technical solution, the quaternized SiO2 aerogel is obtained by modifying SiO2 aerogel with a quaternized silane coupling agent.

[0007] As a further technical solution, the preparation method of the quaternized SiO2 aerogel includes the following steps: SiO2 aerogel was dispersed in a solvent, a quaternized silane coupling agent was added, the reaction was carried out, solid-liquid separation was performed to obtain a solid, which was then washed and dried to obtain quaternized SiO2 aerogel.

[0008] As a further technical solution, the quaternized silane coupling agent includes any one of dimethyloctadecyl[3-(trimethoxysilyl)propyl]ammonium chloride and tetradecyldimethyl[3-(trimethoxysilyl)propyl]ammonium chloride; Preferably, the quaternized silane coupling agent comprises dimethyloctadecyl[3-(trimethoxysilyl)propyl]ammonium chloride.

[0009] As a further technical solution, the reaction temperature is 20~30℃ and the reaction time is 20~24h.

[0010] As a further technical solution, the epoxy resin includes aliphatic epoxy resin and / or phenolic epoxy resin.

[0011] In this invention, the strength of the aerogel antibacterial coating is improved by using aliphatic epoxy resin and / or phenolic epoxy resin in combination. Phenolic epoxy resin is rich in aromatic rigid framework and high-functionality reactive sites, resulting in high curing crosslinking density and the ability to construct a high-strength, dense three-dimensional paint film network. Aliphatic epoxy resin has flexible molecular chains, low internal stress, and excellent aging resistance, balancing the rigidity and toughness of the paint film. The synergistic effect of these two resins significantly improves the interfacial compatibility between quaternized SiO2 aerogel powder and the organic resin. The resin matrix can fully impregnate and encapsulate the modified aerogel particles, further enhancing dispersion uniformity, eliminating stress concentration and microporous defects in the paint film, and strengthening the overall mechanical properties of the coating.

[0012] As a further technical solution, when the epoxy resin includes aliphatic epoxy resin and phenolic epoxy resin, the mass ratio of the aliphatic epoxy resin to the phenolic epoxy resin is 7:3~4.

[0013] In this invention, by optimizing the mass ratio of aliphatic epoxy resin to phenolic epoxy resin to 7:3~4, the characteristics of flexible molecular chains and low internal stress of aliphatic epoxy resin are fully utilized, effectively alleviating the problem of brittle film caused by excessive rigidity of phenolic epoxy resin. At the same time, the high crosslinking density and rigid skeleton of phenolic epoxy resin provide sufficient mechanical support for the coating.

[0014] As a further technical solution, the wetting agent includes a polyether-modified organosilicon wetting agent.

[0015] As a further technical solution, the defoamer includes nonionic polyether modified silicone defoamer and / or mineral oil defoamer; Preferably, the defoamer includes a nonionic polyether-modified silicone defoamer.

[0016] This invention also proposes a method for preparing an aerogel antibacterial coating, comprising the following steps: After mixing epoxy resin, quaternized SiO2 aerogel, antibacterial agent and water, wetting agent and defoamer are added and mixed, and finally curing agent is added and mixed to obtain the aerogel antibacterial coating.

[0017] The working principle and beneficial effects of this invention are as follows: In this invention, the antibacterial properties of the aerogel coating are improved by using quaternized SiO2 aerogel and ε-polylysine in combination. Quaternized SiO2 aerogel can capture negatively charged bacterial cell membranes through electrostatic adsorption. The organic quaternary ammonium salt grafted on the surface is a cationic group that can penetrate the phospholipid bilayer of the bacterial cell membrane, destroying the membrane structure and denaturing intracellular proteins and nucleic acids, causing bacterial lysis and apoptosis, thus achieving contact killing. Furthermore, the quaternization modification improves the dispersibility of silica aerogel in epoxy resin substrates, avoids aggregation defects, improves coating density, and blocks the invasion of external microorganisms and moisture. ε-polylysine is a cationic polypeptide that can penetrate into the bacterial cell, inhibiting the synthesis of microbial nucleic acids and proteins, and hindering bacterial proliferation and metabolism, thus compensating for the insufficient long-term antibacterial effect of a single quaternary ammonium salt. Detailed Implementation

[0018] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. 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 of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0019] In the following examples and comparative examples, dimethyloctadecyl[3-(trimethoxysilyl)propyl]ammonium chloride was a methanol solution of dimethyloctadecyl[3-(trimethoxysilyl)propyl]ammonium chloride with a concentration of 60 wt%. The wetting agent is model number BYK-349; The defoamer's model number is HY-6803; The aliphatic epoxy resin is designated as AG-80. The phenolic epoxy resin is designated as F-51. The type of bisphenol A epoxy resin is E-44; The preparation method of SiO2 aerogel includes the following steps: mixing tetraethoxysilane, anhydrous ethanol and water (the mass ratio of tetraethoxysilane, anhydrous ethanol and water is 1:1.2:0.25), adjusting the pH to 2, hydrolyzing for 12 h, then adjusting the pH to 6 again, aging for 48 h, soaking in n-hexane and drying to obtain SiO2 aerogel.

[0020] Example 1 A method for preparing an aerogel antibacterial coating includes the following steps: After mixing 35 parts epoxy resin, 8 parts quaternized SiO2 aerogel, 1 part ε-polylysine and 25 parts water evenly, 2 parts wetting agent and 0.5 parts defoamer are added and mixed evenly. Finally, 5 parts curing agent 7002S are added and mixed to obtain an aerogel antibacterial coating. The epoxy resin is composed of aliphatic epoxy resin and phenolic epoxy resin in a mass ratio of 7:3. The preparation method of quaternized SiO2 aerogel includes the following steps: 5g of SiO2 aerogel was dispersed in 500mL of a mixed solvent (the mixed solvent consisted of water and anhydrous ethanol in a volume ratio of 1:1), and 2.5mL of dimethyloctadecyl[3-(trimethoxysilyl)propyl]ammonium chloride was added. The mixture was reacted at 20℃ for 24h. The solid was separated from the liquid and washed and dried to obtain quaternized SiO2 aerogel.

[0021] Example 2 A method for preparing an aerogel antibacterial coating includes the following steps: After mixing 45 parts epoxy resin, 12 parts quaternized SiO2 aerogel, 1.5 parts ε-polylysine and 28 parts water evenly, 3 parts wetting agent and 1 part defoamer are added and mixed evenly. Finally, 7 parts curing agent 7002S are added and mixed to obtain an aerogel antibacterial coating. The epoxy resin is composed of aliphatic epoxy resin and phenolic epoxy resin in a mass ratio of 7:4. The preparation method of quaternized SiO2 aerogel includes the following steps: 5g of SiO2 aerogel was dispersed in 500mL of a mixed solvent (the mixed solvent consisted of water and anhydrous ethanol in a volume ratio of 1:1), and 2.5mL of dimethyloctadecyl[3-(trimethoxysilyl)propyl]ammonium chloride was added. The mixture was reacted at 30℃ for 20h. The solid was separated from the liquid and washed and dried to obtain quaternized SiO2 aerogel.

[0022] Example 3 A method for preparing an aerogel antibacterial coating includes the following steps: After mixing 40 parts epoxy resin, 12 parts quaternized SiO2 aerogel, 1.2 parts ε-polylysine and 26 parts water evenly, 2.5 parts wetting agent and 0.8 parts defoamer are added and mixed evenly. Finally, 6 parts curing agent 7002S are added and mixed to obtain an aerogel antibacterial coating. The epoxy resin is composed of aliphatic epoxy resin and phenolic epoxy resin in a mass ratio of 7:4. The preparation method of quaternized SiO2 aerogel includes the following steps: 5g of SiO2 aerogel was dispersed in 500mL of a mixed solvent (the mixed solvent consisted of water and anhydrous ethanol in a volume ratio of 1:1), and 2.5mL of dimethyloctadecyl[3-(trimethoxysilyl)propyl]ammonium chloride was added. The mixture was reacted at 25℃ for 24h. The solid was separated from the liquid and washed and dried to obtain quaternized SiO2 aerogel.

[0023] Example 4 The only difference between this embodiment and Embodiment 3 is that the epoxy resin is composed of aliphatic epoxy resin and phenolic epoxy resin in a mass ratio of 7:3.

[0024] Example 5 The only difference between this embodiment and Embodiment 3 is that the epoxy resin is composed of aliphatic epoxy resin and phenolic epoxy resin in a mass ratio of 7:2.

[0025] Example 6 The only difference between this embodiment and Embodiment 3 is that the epoxy resin is composed of aliphatic epoxy resin and phenolic epoxy resin in a mass ratio of 7:5.

[0026] Example 7 The only difference between this embodiment and Embodiment 3 is that the epoxy resin is composed of aliphatic epoxy resin and bisphenol A type epoxy resin in a mass ratio of 7:4.

[0027] Comparative Example 1 The only difference between this comparative example and Example 3 is that the quaternized SiO2 aerogel is replaced with an equal amount of SiO2 aerogel.

[0028] Comparative Example 2 The only difference between this comparative example and Example 3 is that ε-polylysine is replaced with an equal amount of quaternized SiO2 aerogel.

[0029] Experimental Example 1 Antibacterial performance test: The aerogel antibacterial coatings prepared in Examples 1-3 and Comparative Examples 1-2 were prepared according to GB / T 1727-2021 "General Method for Preparation of Coating Films". The test substrate was a sterilized aluminum plate with dimensions of 70mm×150mm×1mm. The antibacterial rate of the prepared aerogel antibacterial coatings was tested according to the method specified in GB / T 21866-2025 "Determination of Antiviral Activity and Antibacterial Properties of Coating Films". Staphylococcus aureus was selected as the test species. The test results are shown in Table 1. Table 1. Antibacterial performance test results

[0030] By comparing the data of Examples 1-3 and Comparative Examples 1-2, it was found that the antibacterial rate of the aerogel coating obtained by Examples 1-3 by adding quaternized SiO2 aerogel and ε-polylysine was greater than that of Comparative Examples 1-2. This indicates that the antibacterial performance of aerogel coatings can be improved by combining quaternized SiO2 aerogel and ε-polylysine.

[0031] Experimental Example 2 The aerogel antibacterial coatings obtained in Examples 1-8 were prepared according to GB / T 1727-2021 "General Method for Preparing Paint Films". Sterilized aluminum plates with dimensions of 70mm × 150mm × 1mm were selected as the test substrate. Tensile strength was tested according to the method specified in standard JG / T172-2014 "Elastic Building Coatings". The test results are shown in Table 2. Table 2 Tensile strength test results

[0032] By comparing the data from Examples 1-7, the tensile strength of the aerogel antibacterial coating obtained by compounding aliphatic epoxy resin and phenolic epoxy resin in Examples 1-6 was greater than that in Example 7. This indicates that the strength of the aerogel antibacterial coating can be improved by compounding aliphatic epoxy resin and phenolic epoxy resin. By further comparing the data from Examples 1-6, the strength of the aerogel antibacterial coating in Examples 4-5 was further improved by adjusting the mass ratio of aliphatic epoxy resin to phenolic epoxy resin to 7:2-3.

[0033] The above are merely preferred embodiments of the present invention and are 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 aerogel antibacterial coating, characterized in that, It includes the following components by weight: 35-45 parts epoxy resin, 8-12 parts quaternized SiO2 aerogel, 1-1.5 parts antibacterial agent, 15-20 parts curing agent, 2-3 parts wetting agent, 0.5-1 part defoamer, and 25-28 parts water. The antibacterial agent includes ε-polylysine.

2. The aerogel antibacterial coating according to claim 1, characterized in that, The quaternized SiO2 aerogel is obtained by modifying SiO2 aerogel with a quaternized silane coupling agent.

3. The aerogel antibacterial coating according to claim 2, characterized in that, The preparation method of the quaternized SiO2 aerogel includes the following steps: SiO2 aerogel was dispersed in a solvent, a quaternized silane coupling agent was added, the reaction was carried out, solid-liquid separation was performed to obtain a solid, which was then washed and dried to obtain quaternized SiO2 aerogel.

4. The aerogel antibacterial coating according to claim 3, characterized in that, The quaternized silane coupling agent includes any one of dimethyloctadecyl[3-(trimethoxysilyl)propyl]ammonium chloride and tetradecyldimethyl[3-(trimethoxysilyl)propyl]ammonium chloride.

5. The aerogel antibacterial coating according to claim 3, characterized in that, The reaction temperature is 20~30℃, and the reaction time is 20~24h.

6. The aerogel antibacterial coating according to claim 1, characterized in that, The epoxy resin includes aliphatic epoxy resin and / or phenolic epoxy resin.

7. The aerogel antibacterial coating according to claim 6, characterized in that, When the epoxy resin includes aliphatic epoxy resin and phenolic epoxy resin, the mass ratio of the aliphatic epoxy resin to the phenolic epoxy resin is 7:3~4.

8. The aerogel antibacterial coating according to claim 1, characterized in that, The wetting agent includes a polyether-modified silicone wetting agent.

9. The aerogel antibacterial coating according to claim 1, characterized in that, The defoamer includes nonionic polyether-modified silicone defoamers and / or mineral oil-based defoamers.

10. A method for preparing an aerogel antibacterial coating, used to prepare the aerogel antibacterial coating according to any one of claims 1 to 9, characterized in that, Includes the following steps: After mixing epoxy resin, quaternized SiO2 aerogel, antibacterial agent and water, wetting agent and defoamer are added and mixed, and finally curing agent is added and mixed to obtain the aerogel antibacterial coating.

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