A method for preparing an antibacterial self-repairing organic silicon coating

Abstract

The present application discloses a method for preparing an antibacterial self-healing organic silicon coating, belonging to the technical field of organic silicon resin preparation. Octamethylcyclotetrasiloxane, siloxane and / or aminosilane, and a catalyst are sequentially added into a four-necked flask with nitrogen, stirred and heated, and then treated with acid to obtain aminopolysiloxane, and then carbon tetrachloride and methyl acrylate are added. After the addition, sodium hydroxide is added, and the product is heated to reflux and filtered to obtain a liquid product, and then rotary evaporated to obtain an amino acid-modified polysiloxane, the amino acid-modified polysiloxane and a solvent are mixed to obtain component A, an antibacterial cross-linking agent and a solvent are mixed to obtain component B, components A and B are mixed and coated, and the amino acid-modified polysiloxane is obtained after curing for use in a self-healing antibacterial coating; amino acid-modified polysiloxane is synthesized, and the chelation of amino and carboxyl groups to metal ions realizes reversible cross-linking of polysiloxane, which can be repeated many times, and the metal ions have an antibacterial effect, thereby extending the service life of the coating.

Description

Technical Field

[0001] The invention relates to the technical field of organosilicon resin preparation, and in particular to a method for preparing an antibacterial self-repairing organosilicon coating. Background Art

[0002] As people pay more attention to health and the environment, the antibacterial properties of coatings are gradually gaining attention, especially in indoor environments. Antibacterial coatings can inhibit the growth of mold in dark and humid environments, block the growth and spread of bacteria on their surfaces, reduce the spread of diseases, and create a healthier environment. In recent years, they have received more and more attention from the public. However, in current antibacterial coatings, organic antibacterial agents are prone to drug resistance and have poor stability, which limits the application of antibacterial coatings. At the same time, the damage to the coating will also cause the antibacterial agent to leak, which will greatly reduce the antibacterial effect of the coating.

[0003] Silicone coatings have excellent properties such as water resistance, chemical resistance, weather resistance, and high temperature resistance, and they occupy an irreplaceable position in many fields. However, silicone materials are still inevitably susceptible to external damage during use, which shortens their service life and greatly increases the cost of material maintenance and replacement. As a smart material, self-healing materials can repair cracks or local damage caused by external forces during use, thereby restoring their original functions and extending the service life of the material. Since most reversible self-repairs using reversible covalent bonds require external conditions such as energy input (heat, light) or pH changes, which limit the application of self-healing materials, the use of multifunctional metal ligands to achieve high strength, high ductility and room temperature self-healing coatings has extremely high practical application value.

[0004] Chinese patent CN202110840008.9 discloses an antibacterial silicone elastomer and its preparation method and application. This invention uses a monomer derivative B containing catechol residues and a carboxylic acid derivative C containing disulfide bonds to modify the amino-functionalized polysiloxane A to obtain a polysiloxane derivative D containing amide bonds, disulfide bonds and catechol residues; then zinc salt is used to coordinate the catechol residues to obtain a polysiloxane derivative E containing amide bonds, disulfide bonds and metal coordination bonds; the polysiloxane derivative E containing amide bonds, disulfide bonds and metal coordination bonds is mixed evenly with silver nanoparticles, and compounded to obtain a flexible antibacterial conductive silicone composite material. However, considering that traditional silicone composite conductive materials are often prepared by compounding a dynamically cross-linked silicone network with a conductive nanomaterial, but do not have antibacterial properties, and cannot simultaneously have excellent conductivity, sensitive sensing ability, antibacterial ability and long-term stability, the existing technology appears to be slightly insufficient.

[0005] Chinese patent CN202010730258.2 discloses a self-healing, soluble silicone antibacterial elastomer, its preparation method and antibacterial material application. This application uses Schiff base reaction to generate dynamic imine bonds and the N atoms and O atoms on the 1,2,5-oxadiazole heterocycle in 3,4-diaminofurazar to form coordination bonds with zinc ions for reversible crosslinking, and by regulating the molar ratio of metal to ligand, the size of the crosslinking density is adjusted to give it good mechanical properties, solubility and antibacterial properties. However, considering that traditional silicone elastomers form permanent covalent crosslinking networks through peroxide crosslinking, silane hydroaddition crosslinking, etc., and lose self-healing properties and poor solubility, the existing technology appears to be slightly insufficient.

[0006] Chinese patent CN 117468239A discloses an amino acid modified polysiloxane fabric fixing agent, a preparation method and an application thereof, which discloses a polysiloxane compound and an amino acid monomer, which are added into a reaction device containing a reaction solvent, a photoinitiator is added, and the amino acid modified polysiloxane compound is obtained by reaction under ultraviolet light, and has a good antibacterial effect; Chinese patent CN108473771A discloses an organopolysiloxane emulsified composition and a resin composition, wherein the organopolysiloxane is an amino acid modified polysiloxane, and an antibacterial agent such as an oxazoline compound, an aromatic carboxylate and a solvent are mixed to prepare the organopolysiloxane emulsified composition. Chinese patent CN101838395A discloses a preparation method and application of a double-terminal amino silicone oil and its emulsion with conditioning function, which discloses that octamethylcyclotetrasiloxane, hexamethyldisiloxane and aminosilane coupling agent are weighed, mixed, heated to 90-150°C, stirred and reacted for 0.5-3h, a weighed catalyst is added, the catalyst is lithium hydroxide and potassium hydroxide, the temperature is kept for 3-9h, and vacuum is drawn for 0.5-3h; the temperature is cooled to room temperature to obtain a double-terminal amino silicone oil with conditioning function; Chinese patent CN103172867A discloses a preparation method of a double-terminal amino silicone oil co-modified by long-chain alkane and epoxy, and Chinese patent CN117815114A discloses High-efficiency repair hair care additives and preparation methods based on self-emulsifying amino silicone oil, Chinese patent CN110698691A discloses a method for preparing a hydrophobic amino silicone oil emulsion, Chinese patent CN105694062A discloses a cross-linked dendritic amino silicone oil and a preparation method thereof, Chinese patent CN104262631A discloses a low molecular weight linear terminal amino silicone oil and a synthesis method thereof, Chinese patent CN103642044A discloses a preparation method for highly active anti-yellowing modified amino silicone oil, and Chinese patent CN103087326A discloses a preparation method for a polyoxyalkyl epoxy modified amino silicone oil softener, all of which disclose methods for preparing amino silicone oil. Compared with the present application, the above patents have the following technical features: a method for preparing aminopolysiloxane from octamethylcyclotetrasiloxane, aminosilane and a catalyst. The present invention sequentially adds octamethylcyclotetrasiloxane, siloxane and / or aminosilane and a catalyst into a four-necked flask filled with nitrogen, stirs and heats, and then treats with an acid to obtain an aminopolysiloxane whose side chain is modified with a quaternary ammonium salt.

[0007] Chinese patent CN111548501A discloses a method for preparing an amino acid-containing organosilicon surfactant, and discloses a method for preparing an amino acid-containing organosilicon surfactant by adding polyether-modified amino silicone oil into a reaction bottle, and dripping methyl acrylate and sodium hydroxide within 1 hour. Chinese patent CN 114133497A discloses an aqueous polymer emulsion and a preparation method and application thereof, and discloses a method for preparing a polymer emulsion by using a fixed or permanent base such as sodium hydroxide, a water-soluble amino silicone oil, and a nonionic monoethylenically unsaturated monomer methyl methacrylate. Chinese patent CN 116731666A discloses a waterproof quick-drying adhesive and a preparation method thereof, and introduces a cyanoacrylic acid acyl group into a long chain of polysiloxane, takes amino silicone oil, and a thickener selected from polymethyl methacrylate. Sodium hydroxide is dissolved in deionized water at room temperature to prepare a saturated solution. The invention patent with application number 201310509861.8 discloses a high-brightness printing adhesive prepared by emulsion polymerization of butyl acrylate, methyl methacrylate, acrylic acid, diacetone acrylamide, glycidyl methacrylate, amino silicone oil, maleic anhydride, sodium hydroxide, methacryloxypropyl trimethoxysilane, vinyl trimethoxysilane, sodium dodecylbenzene sulfonate, emulsifier AFX1080, emulsifier EF-810, tert-dodecyl alcohol, sodium sulfate of fatty alcohol polyoxyethylene ether, modified attapulgite, and water. Compared with the present application, the above patent has the following technical features: a method for preparing amino acid modified polysiloxane, the present invention utilizes amino polysiloxane, then adds carbon tetrachloride and methyl acrylate, then adds sodium hydroxide, heats and refluxes, filters to obtain a liquid product, and then rotary evaporates to obtain amino acid modified polysiloxane. Summary of the invention

[0008] Technical issues solved:

[0009] The purpose of the present invention is to overcome the technical problems existing in the prior art such as short duration of antibacterial effect, short service life, and difficulty in implementing self-repairing conditions in antibacterial coatings. The present application provides a method for preparing an antibacterial self-repairing silicone coating.

[0010] Technical solution: To achieve the above objectives, this application is implemented through the following technical solutions:

[0011] A method for preparing an antibacterial self-repairing silicone coating comprises the following steps:

[0012] Step 1: weigh 70-80 parts of octamethylcyclotetrasiloxane D4, 10-30 parts of siloxane and / or aminosilane, 0.1-0.2 parts of catalyst, and 2-3 parts of water according to the mass ratio; dissolve the catalyst in water to form a catalyst alkaline solution; add octamethylcyclotetrasiloxane D4, siloxane and / or aminosilane, and the catalyst alkaline solution in a four-necked flask filled with nitrogen in sequence, mix well, stir and heat to 120-150° C. in a constant temperature oil bath, react for 5-12 hours, and treat with acid to obtain aminopolysiloxane:

[0013] Step 2: Take 14-20 parts of aminopolysiloxane, 20-50 parts of carbon tetrachloride, 1.1-2 parts of methyl acrylate, and 0.12-0.22 parts of sodium hydroxide solution by volume; add aminopolysiloxane and carbon tetrachloride to a reaction container, add methyl acrylate dropwise into the reaction container within 1-2 hours, maintain the temperature at 25°C, add sodium hydroxide solution after the addition is completed, heat and reflux for 4-5 hours, filter to obtain a liquid product, and then rotary evaporate to remove the solvent and by-products to obtain amino acid-modified polysiloxane;

[0014] Step 3: Mix 20-50 parts of amino acid modified polysiloxane and 35-60 parts of solvent A according to the mass ratio, and stir evenly to obtain component A;

[0015] Step 4: Mix 1-5 parts of an antibacterial crosslinking agent and 10-80 parts of a solvent B according to the mass ratio, and stir evenly to obtain component B; the antibacterial crosslinking agent is one or more of copper, zinc, and iron salts soluble in alcohol;

[0016] Step 5: Mix component A and component B in a weight ratio of 4-20:1, stir for 10-30 minutes and then apply the coating. After curing, an antibacterial self-healing silicone coating is obtained.

[0017] Preferably, the siloxane in the first step is one or more of methyltrimethoxysilane, methyltriethoxysilane, phenyltrimethoxysilane, n-propyltrimethoxysilane, n-propyltriethoxysilane, dimethyldimethoxysilane and dimethyldiethoxysilane.

[0018] Preferably, the aminosilane in the first step is one or more of γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, N-β (aminoethyl) -γ-propyltrimethoxysilane, N-β (aminoethyl) -γ-aminopropylmethyldimethoxysilane, N-β-(aminoethyl) -γ-aminopropyltriethoxysilane, aminopropyldiethoxymethylsilane, and aminoethylaminopropyltrimethoxysilane.

[0019] Preferably, the catalyst in the first step is one or more of potassium hydroxide, sodium hydroxide, aqueous ammonia, sodium ethoxide, sodium methoxide, and tetramethylammonium hydroxide.

[0020] Preferably, the acid treatment in the first step is to adjust the pH to neutral with an acid, and the acid is acetic acid or sulfuric acid.

[0021] Preferably, the reaction vessel in the second step is a four-necked flask equipped with a thermometer, a reflux condenser and a magnet.

[0022] Preferably, the alcohol-soluble copper, zinc, and iron salts are one or more of zinc bromide, copper bromide, iron bromide, iron tetrafluoroborate, copper tetrafluoroborate, zinc tetrafluoroborate, copper acetate, zinc acetate, and iron acetate.

[0023] Preferably, the solvent A and the solvent B are respectively one or more of ethanol, isopropanol, ethylene glycol monoethyl ether, and ethylene glycol monobutyl ether.

[0024] Preferably, the preparation formula of the amino acid-modified polysiloxane is as follows: ; Wherein: R1 = methyl or methoxy or ethoxy; R2 = propyl or N-propylethyl; R3 = one of methyl, methoxy, ethoxy, phenyl, n-propyl; R4 = one of methyl, methoxy, ethoxy, m = 2 ~ 5, n = 4 ~ 20.

[0025] The technical principle of the present invention is: the present application modifies aminopolysiloxane through the addition reaction of amino groups to double bonds to synthesize amino acid-modified polysiloxane, and utilizes the strong complexing ability of amino groups and carboxyl groups in amino acid-modified polysiloxane to transition metals to achieve reversible crosslinking of polysiloxane. The metal coordination reaction can achieve intrinsic self-repair of the coating without the need for external conditions (light / heat, etc.); this patent uses metal ions as antibacterial crosslinking agents, which can achieve reversible self-repair on the one hand, and use metal ions to achieve antibacterial and antifungal effects on the other hand, thereby increasing the service life of the coating.

[0026] Beneficial effects:

[0027] The present application provides a method for preparing an antibacterial self-repairing silicone coating, which has the following beneficial effects:

[0028] 1. This application utilizes the multifunctional metal coordination chelation effect to achieve high-strength room temperature self-repair;

[0029] 2. The present application synthesizes amino acid-modified polysiloxane and utilizes the chelation of amino and carboxyl groups to metal ions to achieve reversible cross-linking of polysiloxane. This metal coordination effect does not require external heating or pH conditions and can be repeated many times. In addition, the metal ions have antibacterial effects, which greatly prolongs the service life of the coating.

[0030] 3. Compared with the antibacterial silicone elastomer and its preparation method and application disclosed in CN202110840008.9, this application adopts amino acid-modified silicone coordinated with metal ions, without adding additional silver nanoparticles, which reduces the cost and has a simple system;

[0031] 4. Compared with the self-repairing, soluble organosilicon antibacterial elastomer and its preparation method and antibacterial material application disclosed in CN202010730258.2, the self-repairing group of this application is different. The Schiff base reaction generates a dynamic imine bond, while the amino acid modified siloxane used in this patent is cross-linked with the coordination bond of the metal;

[0032] 5. Compared with the preparation method of a high-strength self-healing silicone-modified polyurea marine antifouling coating containing disulfide bonds disclosed in CN117820949A, the present application fixes the antibacterial agent in the coating by chelation, which is not easy to lose and the antibacterial effect is maintained for a long time. DETAILED DESCRIPTION

[0033] The present invention is described in detail below in conjunction with specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those of ordinary skill in the art, several variations and improvements may be made without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

[0034] Embodiment 1: A method for preparing an antibacterial self-repairing silicone coating, comprising the following steps:

[0035] Step 1: Weigh 75 parts of octamethylcyclotetrasiloxane D4, 10 parts of aminopropyldiethoxymethylsilane, 2 parts of water and 0.1 parts of catalyst KOH according to the mass ratio, dissolve the catalyst in water to form a catalyst alkaline solution, add octamethylcyclotetrasiloxane D4, aminopropyldiethoxymethylsilane and the catalyst alkaline solution in a four-necked flask with nitrogen in turn, mix well, stir and heat to 140°C in a constant temperature oil bath, react for 10 hours, and adjust the pH to neutral with acetic acid to obtain aminopolysiloxane:

[0036] Step 2: Add 14 parts of aminopolysiloxane and 50 parts of carbon tetrachloride by volume into a four-necked flask equipped with a thermometer, a reflux condenser and a magnet, and dropwise add 1.2 parts of methyl acrylate into the reaction vessel within 0.5 h, maintain the temperature at 25° C., add 0.15 parts of sodium hydroxide solution after the reaction is completed, heat and reflux for 5 h, filter to obtain a liquid product, and then rotary evaporate to remove the solvent and by-products to obtain amino acid-modified polysiloxane;

[0037] Step 3: Mix 20 parts of amino acid-modified polysiloxane and 40 parts of isopropanol solvent according to the mass ratio, and stir evenly to obtain component A;

[0038] Step 4: Mix 3 parts of antibacterial cross-linking agent copper bromide and 20 parts of solvent isopropanol according to the mass ratio, and stir evenly to obtain component B;

[0039] Step 5: Component A and component B are mixed in a weight ratio of 10:1, and the mixture is coated after stirring for 30 minutes. After curing, an antibacterial self-healing silicone coating S1 is obtained.

[0040] Embodiment 2: A method for preparing an antibacterial self-repairing silicone coating, comprising the following steps:

[0041] Step 1: Weigh 80 parts of octamethylcyclotetrasiloxane D4, 30 parts of aminopropyldiethoxymethylsilane, 3 parts of water and 0.1 parts of catalyst KOH according to the mass ratio, dissolve the catalyst in water to form a catalyst alkaline solution; add octamethylcyclotetrasiloxane D4, aminopropyldiethoxymethylsilane and catalyst alkaline solution in a four-necked flask with nitrogen in turn, mix well, stir and heat to 120°C in a constant temperature oil bath, react for 10 hours, and adjust the pH to neutral with acetic acid to obtain aminopolysiloxane:

[0042] Step 2: Add 20 parts of aminopolysiloxane and 50 mL of carbon tetrachloride according to volume ratio into a four-necked flask equipped with a thermometer, a reflux condenser and a magnet, and dropwise add 2 parts of methyl acrylate into the reaction container within 1 hour, maintaining the temperature at 25°C. After the reaction is completed, add 0.22 parts of sodium hydroxide solution, heat and reflux for 5 hours, filter to obtain a liquid product, and then rotary evaporate to remove the solvent and by-products to obtain amino acid-modified polysiloxane;

[0043] Step 3: Mix 20 parts of amino acid-modified polysiloxane and 60 parts of isopropanol solvent according to the mass ratio, and stir for 15 minutes until the mixture is evenly dispersed to obtain component A;

[0044] Step 4: Mix 3 parts of antibacterial crosslinking agent zinc tetrafluoroborate and 30 parts of solvent ethanol according to the mass ratio, and stir evenly to obtain component B;

[0045] Step 5: Mix component A and component B in a weight ratio of 5:1, stir for 30 minutes and then apply a coating. After curing, an antibacterial self-healing silicone coating S2 is obtained.

[0046] Embodiment 3: A method for preparing an antibacterial self-repairing silicone coating, comprising the following steps:

[0047] Step 1: Weigh 70 parts of octamethylcyclotetrasiloxane D4, 20 parts of γ-aminopropyltrimethoxysilane, 2 parts of water and 0.1 parts of catalyst KOH according to the mass ratio, dissolve the catalyst in water to form a catalyst alkaline solution; add octamethylcyclotetrasiloxane D4, γ-aminopropyltrimethoxysilane and catalyst alkaline solution in a four-necked flask with nitrogen in turn, mix well, stir and heat to 140°C in a constant temperature oil bath, react for 6 hours, and adjust the pH to neutral with sulfuric acid to obtain aminopolysiloxane:

[0048] Step 2: Add 15 parts of aminopolysiloxane and 50 mL of carbon tetrachloride according to volume ratio into a four-necked flask equipped with a thermometer, a reflux condenser and a magnet, and dropwise add 1.7 parts of methyl acrylate into the reaction container within 0.5 h, maintain the temperature at 25° C., add 0.22 parts of sodium hydroxide solution after the reaction is completed, heat and reflux for 4 h, filter to obtain a liquid product, and then rotary evaporate to remove the solvent and by-products to obtain amino acid-modified polysiloxane;

[0049] Step 3: Mix 20 parts of amino acid modified polysiloxane and 50 parts of ethylene glycol monobutyl ether according to the mass ratio, and stir evenly to obtain component A;

[0050] Step 4: Mix 2 parts of antibacterial cross-linking agent copper bromide and 30 parts of solvent ethanol according to the mass ratio, and stir evenly to obtain component B;

[0051] Step 5: Mix component A and component B in a weight ratio of 7:1, stir for 30 minutes and then apply a coating, and after curing, obtain an antibacterial self-healing silicone coating S3.

[0052] Embodiment 4: A method for preparing an antibacterial self-repairing silicone coating, comprising the following steps:

[0053] Step 1: Weigh 75 parts of octamethylcyclotetrasiloxane D4, 20 parts of γ-aminopropyltriethoxysilane, 2 parts of water and 0.2 parts of catalyst KOH according to the mass ratio, dissolve the catalyst in water to form a catalyst alkaline solution; add octamethylcyclotetrasiloxane D4, γ-aminopropyltriethoxysilane and catalyst alkaline solution in a four-necked flask with nitrogen in turn, mix well, stir and heat to 140°C in a constant temperature oil bath, react for 10 hours, and adjust the pH to neutral with acetic acid to obtain aminopolysiloxane:

[0054] Step 2: Add 10 parts of aminopolysiloxane and 50 mL of carbon tetrachloride according to volume ratio into a four-necked flask equipped with a thermometer, a reflux condenser and a magnet, and dropwise add 1.1 parts of methyl acrylate into the reaction container within 1 hour, maintain the temperature at 25°C, add 0.12 parts of sodium hydroxide solution after the reaction is completed, heat and reflux for 5 hours, filter to obtain a liquid product, and then rotary evaporate to remove the solvent and by-products to obtain amino acid-modified polysiloxane;

[0055] Step 3: Take 20 parts of amino acid modified polysiloxane and 50 parts of solvent ethanol according to the mass ratio, mix them, and stir them evenly to obtain component A;

[0056] Step 4: Mix 2 parts of antibacterial cross-linking agent copper acetate and 30 parts of solvent ethanol according to the mass ratio, and stir evenly to obtain component B;

[0057] Step 5: Mix component A and component B in a weight ratio of 10:1, stir for 30 minutes and then apply a coating, and after curing, obtain an antibacterial self-healing silicone coating S4.

[0058] Embodiment 5: A method for preparing an antibacterial self-repairing silicone coating, comprising the following steps:

[0059] Step 1: Weigh 70 parts of octamethylcyclotetrasiloxane D4, 15 parts of aminopropyldiethoxymethylsilane, 2 parts of water and 0.2 parts of catalyst KOH according to the mass ratio, dissolve the catalyst in water to form a catalyst alkaline solution; add octamethylcyclotetrasiloxane D4, aminopropyldiethoxymethylsilane and catalyst alkaline solution in a four-necked flask with nitrogen in turn, mix well, stir and heat to 140°C in a constant temperature oil bath, react for 6 hours, and adjust the pH to neutral with acetic acid to obtain aminopolysiloxane:

[0060] Step 2: Add 15 parts of aminopolysiloxane and 20 mL of carbon tetrachloride to a four-necked flask equipped with a thermometer, a reflux condenser and a magnet by volume, and dropwise add 1.4 parts of methyl methacrylate into the reaction vessel within 1 hour, maintaining the temperature at 25°C. After the reaction is completed, add 0.15 parts of sodium hydroxide solution, heat and reflux for 5 hours, filter to obtain a liquid product, and then rotary evaporate to remove the solvent and by-products to obtain amino acid-modified polysiloxane;

[0061] Step 3: Mix 30 parts of amino acid-modified polysiloxane and 50 parts of isopropanol solvent according to the mass ratio, and stir evenly to obtain component A;

[0062] Step 4: Mix 2 parts of antibacterial cross-linking agent ferric tetrafluoroborate and 30 parts of solvent isopropanol according to the mass ratio, and stir evenly to obtain component B;

[0063] Step 5: Mix component A and component B in a weight ratio of 8:1, stir for 30 minutes and then apply a coating. After curing, an antibacterial self-healing silicone coating S5 is obtained.

[0064] Embodiment 6: A method for preparing an antibacterial self-repairing silicone coating, comprising the following steps:

[0065] Step 1: Weigh 70 parts of octamethylcyclotetrasiloxane D4, 25 parts of aminopropyldiethoxymethylsilane, 5 parts of methyltrimethoxysilane, 2 parts of water and 0.1 parts of catalyst KOH according to the mass ratio, dissolve the catalyst in water to form a catalyst alkaline solution; add octamethylcyclotetrasiloxane D4, aminopropyldiethoxymethylsilane, methyltrimethoxysilane and catalyst alkaline solution in a four-necked flask with nitrogen in turn, mix well, stir and heat to 140°C in a constant temperature oil bath, react for 12 hours, and adjust the pH to neutral with acetic acid to obtain aminopolysiloxane:

[0066] Step 2: Add 15 parts of aminopolysiloxane and 50 mL of carbon tetrachloride according to volume ratio into a four-necked flask equipped with a thermometer, a reflux condenser and a magnet, and dropwise add 2 parts of methyl acrylate into the reaction container within 1 hour, maintaining the temperature at 25°C. After the reaction is completed, add 0.22 parts of sodium hydroxide solution, heat and reflux for 5 hours, filter to obtain a liquid product, and then remove the solvent and by-products by rotary evaporation to obtain amino acid-modified polysiloxane;

[0067] Step 3: Mix 30 parts of amino acid-modified polysiloxane and 60 parts of solvent ethanol according to the mass ratio, and stir evenly to obtain component A;

[0068] Step 4: Mix 1 part of antibacterial crosslinking agent zinc tetrafluoroborate and 30 parts of solvent ethanol according to the mass ratio, and stir evenly to obtain component B;

[0069] Step 5: Mix component A and component B in a weight ratio of 7:1, apply film after stirring for 30 minutes, and cure for 24 hours to obtain the antibacterial self-healing silicone coating S6.

[0070] Comparative Example 1: A method for preparing an antibacterial self-repairing silicone coating, comprising the following steps:

[0071] Step 1: Weigh 75 parts of octamethylcyclotetrasiloxane D4, 20 parts of aminopropyldiethoxymethylsilane, 2 parts of water and 0.1 parts of catalyst KOH according to the mass ratio, dissolve the catalyst in water to form a catalyst alkaline solution; add octamethylcyclotetrasiloxane D4, aminopropyldiethoxymethylsilane and catalyst alkaline solution in a four-necked flask with nitrogen in turn, mix well, stir and heat to 140°C in a constant temperature oil bath, react for 10 hours, and adjust the pH to neutral with acetic acid to obtain aminopolysiloxane with quaternary ammonium salt modified side chain:

[0072] Step 2: Add 15 parts of aminopolysiloxane with quaternary ammonium salt as the side chain and 50 mL of carbon tetrachloride to a four-necked flask equipped with a thermometer, a reflux condenser and a magnet by volume, add 2.1 parts of methyl acrylate dropwise into the reaction vessel within 1 hour, maintain the temperature at 25°C, add 0.22 parts of sodium hydroxide solution after the reaction is completed, heat and reflux for 5 hours, filter to obtain a liquid product, and then remove the solvent and by-products by rotary evaporation to obtain amino acid-modified polysiloxane;

[0073] Step 3: Mix 3 parts of amino acid-modified polysiloxane and 9 parts of solvent ethanol according to the mass ratio, stir for 15 minutes until evenly dispersed to obtain component A; add 1 part of ethanol solution of magnesium chloride to the above solution (the mass ratio of magnesium chloride to amino acid-modified polysiloxane is 1:4), mix evenly and apply film, and dry for 24 hours to obtain the self-healing antibacterial coating CS1.

[0074] Comparative Example 2: A method for preparing a silicone coating, comprising the following steps:

[0075] Step 1: Weigh 50 parts of octamethylcyclotetrasiloxane D4, 20 parts of aminopropyldiethoxymethylsilane, 2 parts of water and 0.1 parts of catalyst KOH by mass, dissolve the catalyst in water to form a catalyst alkaline solution; add octamethylcyclotetrasiloxane D4, aminopropyldiethoxymethylsilane and catalyst alkaline solution in a four-necked flask filled with nitrogen in sequence, mix well, stir and heat to 140°C in a constant temperature oil bath, react for 10 hours, and adjust the pH to neutral with acetic acid to obtain aminopolysiloxane with quaternary ammonium salt modified side chain:

[0076] Step 2: 50 parts of octamethylcyclotetrasiloxane D4, 20 parts of KH560, 2 parts of water and 0.1 parts of catalyst KOH were added in a four-necked flask filled with nitrogen in accordance with the mass ratio, and after being evenly mixed, the mixture was stirred and heated to 140°C in a constant temperature oil bath for 10 hours, and the pH was adjusted to neutral with acetic acid to obtain aminopolysiloxane with epoxy modified side chains;

[0077] Step 3: Mix the above two polysiloxanes in equal proportions and then apply the coating, dry and cure for 24 hours to obtain the self-organic silicone coating CS2.

[0078] Performance Test:

[0079] Self-healing performance:

[0080] A scratch with a width of less than 50 μm was made on the completely cured coatings of the self-healing coating materials S1-S6 prepared in Examples 1-6 and the coating materials CS1 and CS2 prepared in Comparative Examples 1 and 2 using a sharp blade, and the time taken for self-healing of each sample was recorded.

[0081] Antibacterial effect:

[0082] sample Room temperature repair time 50℃ repair time Escherichia coli inhibition rate Staphylococcus aureus inhibition rate Candida albicans inhibition rate S1 5h 1h 99.9% 99.9% 99.9% S2 4h 30min 99.9% 99.9% 99.9% S3 3h 30min 99.9% 99.9% 99.9% S4 4h 40min 99.7% 99.8% 99.7% S5 6h 1h20min 99.9% 99.5% 99.9% S6 4h 50 min 99.9% 99.9% 99.9% CS1 —— —— 78.7% 60.2% 65.3% CS2 —— —— 50.5% 45.7% 50.9% The embodiment is an amino acid-modified polysiloxane resin with zinc / copper / iron ion chelation reversible crosslinking. Compared with the magnesium ion chelation crosslinking in Comparative Example 1, there is no empty d orbital for coordination, so the self-repair of Comparative Example 1 is difficult to achieve. At the same time, the antibacterial effect of magnesium ions is worse than that of zinc ions, and the antibacterial rates of Escherichia coli in Comparative Example 1 are worse than those of the embodiment. In Comparative Example 2, the reaction of amino groups and epoxy groups is used to produce non-dynamic chemical bond crosslinking. This crosslinking method is irreversible, so it does not have the ability to self-repair after scratching. At the same time, since zinc ions with antibacterial ability are not added, the coating does not have a good antibacterial effect.

[0083] The above description of the examples is to facilitate the understanding and use of the invention by those skilled in the art. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative work. Therefore, the present invention is not limited to the above embodiments, and improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the present invention should be within the scope of protection of the present invention.

Claims

1. A method for preparing an antibacterial self-repairing silicone coating, characterized in that: The following steps are involved: Step 1: Weigh 70-80 parts of octamethylcyclotetrasiloxane D4, 10-30 parts of aminosilane, 0.1-0.2 parts of catalyst, and 2-3 parts of water according to the mass ratio, and dissolve the catalyst in water to form a catalyst alkaline solution; add octamethylcyclotetrasiloxane D4, aminosilane, and catalyst alkaline solution in a four-necked flask with nitrogen in turn, mix well, stir and heat to 120-150°C in a constant temperature oil bath, react for 5-12 hours, and treat with acid to obtain aminopolysiloxane: Step 2: Take 14-20 parts of aminopolysiloxane, 20-50 parts of carbon tetrachloride, 1.1-2 parts of methyl acrylate, and 0.12-0.22 parts of sodium hydroxide solution by volume; add aminopolysiloxane and carbon tetrachloride to a reaction container, add methyl acrylate dropwise into the reaction container within 1-2 hours, maintain the temperature at 25°C, add sodium hydroxide solution after the addition is completed, heat and reflux for 4-5 hours, filter to obtain a liquid product, and then rotary evaporate to remove the solvent and by-products to obtain amino acid-modified polysiloxane; Step 3: Mix 20-50 parts of amino acid modified polysiloxane and 35-60 parts of solvent A according to the mass ratio, and stir evenly to obtain component A; Step 4: Mix 1-5 parts of an antibacterial crosslinking agent and 10-80 parts of a solvent B according to the mass ratio, and stir evenly to obtain component B; the antibacterial crosslinking agent is one or more of copper, zinc, and iron salts soluble in alcohol; Step 5: Mix component A and component B in a weight ratio of 4-20:1, stir for 10-30 minutes and then apply the coating, and after curing, obtain an antibacterial self-healing silicone coating; The solvent A and the solvent B are respectively one or more of ethanol, isopropanol, ethylene glycol monoethyl ether, and ethylene glycol monobutyl ether.

2. The method for preparing the antibacterial self-repairing silicone coating according to claim 1, characterized in that: The aminosilane in the first step is one or more of γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, N-β-(aminoethyl)-γ-aminopropylmethyldimethoxysilane, N-β-(aminoethyl)-γ-aminopropyltriethoxysilane, aminopropyldiethoxymethylsilane, and aminoethylaminopropyltrimethoxysilane.

3. The method for preparing the antibacterial self-repairing silicone coating according to claim 1, characterized in that: The catalyst in the first step is one or more of potassium hydroxide, sodium hydroxide, aqueous ammonia, sodium ethoxide, sodium methoxide, and tetramethylammonium hydroxide.

4. The method for preparing the antibacterial self-repairing silicone coating according to claim 1, characterized in that: The acid treatment in the first step is to adjust the pH to neutral with an acid, and the acid is acetic acid or sulfuric acid.

5. The method for preparing the antibacterial self-repairing silicone coating according to claim 1, characterized in that: The reaction vessel in the second step is a four-necked flask equipped with a thermometer, a reflux condenser and a magnet.

6. The method for preparing the antibacterial self-repairing silicone coating according to claim 1, characterized in that: The alcohol-soluble copper, zinc and iron salts are one or more of zinc bromide, copper bromide, iron bromide, iron tetrafluoroborate, copper tetrafluoroborate, zinc tetrafluoroborate, copper acetate, zinc acetate and iron acetate.