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CN-122011939-A - Dual-mechanism antibacterial siloxane coating and application thereof

CN122011939ACN 122011939 ACN122011939 ACN 122011939ACN-122011939-A

Abstract

The invention discloses a double-mechanism antibacterial siloxane coating and application thereof, wherein the coating is formed in situ by hydrolysis polycondensation reaction of precursors containing triethoxy octyl silane, nano titanium dioxide and a film-forming adhesive, wherein partial triethoxy octyl silane is hydrolyzed and polycondensed on the surface of the nano titanium dioxide to form a siloxane coating layer containing hydrophobic octyl side chains, the siloxane coating layer is chemically bonded with the surface of the nano titanium dioxide through Si-O-Ti covalent bonds, the residual triethoxy octyl silane is self-polycondensed to form a continuous three-dimensional siloxane network serving as a film-forming matrix of the coating, and the film-forming adhesive is dispersed in the siloxane network.

Inventors

  • QIU JIA
  • LIANG TAO

Assignees

  • 北京优佳速博生物科技有限公司

Dates

Publication Date
20260512
Application Date
20260324

Claims (10)

  1. 1. A dual-mechanism antibacterial siloxane coating is characterized in that the coating is formed in situ by hydrolysis polycondensation reaction of precursors containing triethoxy octyl silane, nano titanium dioxide and a film-forming binder; Wherein, partial triethoxy octyl silane is hydrolyzed and condensed on the surface of the nano titanium dioxide to form a siloxane coating layer containing hydrophobic octyl side chains, and the siloxane coating layer is chemically bonded with the surface of the nano titanium dioxide through Si-O-Ti covalent bonds; the residual triethoxy octyl silane is self-polycondensed to form a continuous three-dimensional siloxane network which is used as a film forming matrix of the coating; The film-forming binder is dispersed in the silicone network; optionally, the coating further comprises an auxiliary agent selected from at least one of a dispersant, a leveling agent or a defoamer.
  2. 2. The dual-mechanism antimicrobial siloxane coating according to claim 1, wherein the nano titanium dioxide has a particle size of no more than 50nm and is in the anatase form.
  3. 3. The dual-mechanism antimicrobial silicone coating according to claim 1, wherein the film-forming binder is selected from at least one of a fluorosilicone resin, a silicone-acrylic emulsion, or a low molecular weight hydroxyl-terminated polysiloxane, and has a solids content of 10% to 30%.
  4. 4. The dual-mechanism antimicrobial siloxane coating according to claim 1, comprising 3% -8% of nano titanium dioxide by weight of the total dry film of the coating, wherein the surface of the nano titanium dioxide is modified by triethoxy octyl silane, 5% -12% of film forming adhesive by weight of the nano titanium dioxide, and the balance of siloxane network matrix formed by hydrolytic polycondensation of triethoxy octyl silane.
  5. 5. The dual-mechanism antimicrobial silicone coating according to any one of claims 1 to 4, wherein the silicone coating meets one or more of the following properties: The contact angle of the solidified water is more than or equal to 150 degrees; The water vapor transmittance is more than or equal to 800 g/(m 2 .24 h); Under the irradiation of ultraviolet light with the wavelength less than or equal to 400nm, the sterilization rate of the bacillus subtilis for 2 hours is more than or equal to 98 percent.
  6. 6. A method of preparing a dual-regime antimicrobial silicone coating according to any one of claims 1 to 5, comprising the steps of: S1, dissolving triethoxy octyl silane in an alcohol/water mixed solvent, and hydrolyzing for 0.5-4 hours under an acidic condition to obtain a silanol solution; S2, adding nano titanium dioxide powder into a silanol solution, controlling the mass ratio of triethoxy octyl silane to nano titanium dioxide to be (2:1) to (5:1), stirring and reacting for 4-12 hours at 40-70 ℃, and enabling silanol to form a siloxane coating layer on the surface of titanium dioxide by polycondensation, and simultaneously enabling part of silanol to self-polycondense to obtain a siloxane precursor dispersion liquid containing modified titanium dioxide; S3, adding a film forming adhesive and an auxiliary agent into the dispersion liquid, and uniformly mixing to obtain a coating precursor solution; And S4, applying the precursor solution to the surface of the substrate, and performing hydrolytic polycondensation curing to form the siloxane coating.
  7. 7. The process according to claim 6, wherein the alcohol in step S1 is ethanol or isopropanol, the molar ratio of water to triethoxyoctylsilane is (2-4) 1, and the pH is 3-5.
  8. 8. The use of a dual-mechanism antimicrobial siloxane coating according to any one of claims 1-5, wherein the relics are stone, ceramic, brick and tile porous inorganic relics and mural organic matter composite relics.
  9. 9. The use according to claim 8, wherein the coating is applied as a precursor solution to the surface of a clean and dry relic by spraying, brushing or dipping, and cured for 24-72 hours at normal temperature and humidity to form a transparent protective film with a thickness of 0.5-5 μm.
  10. 10. The dual-mechanism antimicrobial silicone coating of claim 1, wherein the silicone coating has a thickness of 1-5nm.

Description

Dual-mechanism antibacterial siloxane coating and application thereof Technical Field The invention relates to the technical field of cultural heritage protection materials, in particular to a double-mechanism antibacterial siloxane coating and application thereof. Background The stone cultural relics are exposed in natural environment for a long time and are easy to be influenced by moisture permeation, microbial corrosion and ultraviolet ageing, traditional protective agents such as acrylic resin and fluorocarbon materials are waterproof, but the air permeability is seriously insufficient, industry data show that the natural water vapor permeability of untreated limestone and other base materials is generally 800-1500 g/(m 2.24 h), the water vapor permeability value of the untreated limestone and other base materials is suddenly reduced after the traditional protective agents are coated, wherein the cured film of the acrylic resin (such as Paraloid B-72) is compact, the water vapor permeability is generally only 10-50 g/(m 2.24 h), the fluorocarbon resins are excellent in weather resistance, but the air permeability is worse due to the highly crystalline molecular structure, the water vapor permeability is often lower than 10 g/(m 2.24 h), and the barrier rate of the two to water vapor exchange is as high as 90% -99%. In recent years, nanometer titanium dioxide is widely studied for cultural relic protection due to excellent photocatalytic activity, self-cleaning performance and ultraviolet resistance, however, the titanium dioxide is difficult to uniformly disperse on a hydrophobic substrate and easy to agglomerate in practical application, the effective specific surface area is reduced, the hole pair recombination rate is high, the antibacterial efficiency is limited, and the strong oxidizing property can potentially damage organic cultural relic components. In order to solve the above problems, researchers have tried to regulate the interfacial properties of titanium dioxide by surface modification, wherein siloxane compounds become ideal modifying media due to their good film forming property, air permeability and chemical compatibility with inorganic substrates, triethoxy octyl silane is used as a typical long-chain alkylsilane, and after hydrolytic polycondensation, a three-dimensional siloxane network with hydrophobic side chains can be formed, which can provide physical barriers and anchor functional particles. However, in the prior art, there is no report of the cooperative construction of a coating system with physical barrier and chemical sterilization dual-mechanism antibacterial functions by using siloxane modified titanium dioxide and an adhesive, and successful application of the coating system to cultural relic body protection. Disclosure of Invention The invention aims to provide a double-mechanism antibacterial siloxane coating, a preparation method and application thereof, and the coating has super-hydrophobic, self-cleaning, ultraviolet-resistant and long-acting antibacterial properties, keeps good air permeability, and is suitable for green, safe and long-acting protection of the surface of porous cultural relics. In order to achieve the above purpose, the present invention provides the following technical solutions: A kind of dual-mechanism antibacterial siloxane coating, this coating is formed by precursor comprising triethoxyoctyl silane, nanometer titanium dioxide and film-forming adhesive through hydrolytic polycondensation reaction in situ; Wherein, partial triethoxy octyl silane is hydrolyzed and condensed on the surface of the nano titanium dioxide to form a siloxane coating layer containing hydrophobic octyl side chains, and the siloxane coating layer is chemically bonded with the surface of the nano titanium dioxide through Si-O-Ti covalent bonds; the residual triethoxy octyl silane is self-polycondensed to form a continuous three-dimensional siloxane network which is used as a film forming matrix of the coating; The film-forming binder is dispersed in the silicone network; optionally, the coating further comprises an auxiliary agent selected from at least one of a dispersant, a leveling agent or a defoamer. Further, the particle size of the nano titanium dioxide is not more than 50nm, preferably 1-30 nm, and the crystal form is anatase. Further, the film-forming binder is at least one selected from fluorosilicone resin, silicone-acrylic emulsion or low molecular weight hydroxyl-terminated polysiloxane, and has a solid content of 10% -30%. Further, the coating comprises 3-8% of nano titanium dioxide by weight of the total mass of the coating dry film, wherein the surface of the nano titanium dioxide is modified by triethoxy octyl silane by weight of the nano titanium dioxide, 5-12% of film forming adhesive is formed, and the balance is a siloxane network matrix formed by hydrolytic polycondensation of the triethoxy octyl silane. Further, the silicone coating may meet one or