Antibacterial and antifogging coating, preparation method thereof and refrigerator

Abstract

The invention discloses an antibacterial and antifogging coating, a preparation method thereof and a refrigerator, and belongs to the technical field of polymer synthesis. According to the technical scheme, the antibacterial coating comprises an acrylic emulsion, wherein the acrylic emulsion comprises an acrylic monomer, an acrylamide monomer, an acrylate monomer, a quaternary ammonium salt antibacterial agent, N-vinyl pyrrolidone, a cross-linking agent, an initiator, a compound emulsifier and a first pH regulator; the quaternary ammonium salt antibacterial agent is prepared by the following steps: adding alkyl dimethyl tertiary amine and 3-chloropropene into an ethanol solution with the same mass, heating, stirring and refluxing, finally washing with acetone, and drying to obtain the quaternary ammonium salt antibacterial agent. The polymer is applied to antifogging and antibacterial aspects of the refrigerator, solves the problem that the antibacterial and antifogging performance of the existing polymer still cannot meet the use requirements of the refrigerator, and has excellent antibacterial and antifogging performance.

Description

Technical Field

[0001] The present invention belongs to the technical field of polymer synthesis, and particularly relates to an antibacterial and antifogging coating, a preparation method thereof, and a refrigerator. Background Art

[0002] According to the requirements of European and American countries, antibacterial coatings are often applied to the aluminum alloy air duct decorative plates of our company's exported refrigerators. However, when the refrigerator door is opened, due to the temperature difference between the inside and outside, the surface of the aluminum alloy air duct decorative plate often "forms white fog", affecting the user experience.

[0003] Chinese Patent CN117143280A discloses a polymer for reuse of fracturing flowback fluid and a preparation method thereof. In this patent, acrylamide, acrylic acid, 2-acrylamido-2-methylpropanesulfonic acid, octadecyl allyl dimethyl ammonium chloride, and N-vinyl pyrrolidone are subjected to free radical copolymerization, and the hydrophobic association of octadecyl allyl dimethyl ammonium chloride is used to achieve the drag reduction and viscosity increase effects of the polymer. However, the antibacterial and antifogging properties of the polymer prepared by the above patent still cannot meet the use requirements of refrigerators. Summary of the Invention

[0004] Aiming at the deficiencies of the existing technology, the technical problem to be solved by the present invention is to overcome the problem that the antibacterial and antifogging properties of the existing polymer still cannot meet the use requirements of refrigerators, and to provide an antibacterial and antifogging coating with excellent antibacterial and antifogging properties, a preparation method thereof, and a refrigerator.

[0005] To solve the above technical problem, the technical solution adopted by the present invention is as follows:

[0006] On the one hand, the present invention provides an antibacterial and antifogging coating, which comprises an acrylic emulsion. The acrylic emulsion includes: acrylic monomer, acrylamide monomer, acrylate monomer, quaternary ammonium salt antibacterial agent, N-vinyl pyrrolidone, crosslinking agent, initiator, composite emulsifier, first pH regulator; the quaternary ammonium salt antibacterial agent is prepared by the following method: adding alkyl dimethyl tertiary amine and 3-chloropropene to an equal mass of ethanol solution, heating and stirring under reflux, and finally washing with acetone and drying to obtain the quaternary ammonium salt antibacterial agent.

[0007] Preferably, by weight, the acrylic emulsion is composed of 10-25 parts by weight of acrylic monomer, 10-25 parts by weight of acrylamide monomer, 12-30 parts by weight of acrylate monomer, 46-115 parts by weight of quaternary ammonium salt antibacterial agent, 16-40 parts by weight of N-vinyl pyrrolidone, 20-50 parts by weight of crosslinking agent, 0.1-1 part by weight of initiator, 0.5-5 parts by weight of composite emulsifier, 140-200 parts by weight of deionized water, and 0.5-5 parts by weight of first pH regulator.

[0008] Preferably, the quaternary ammonium salt antibacterial agent is prepared by the following method: adding an alkyl dimethyl tertiary amine and 3-chloropropene with a mass molar ratio of 1:1.05 into an equal mass of ethanol solution, stirring and refluxing at 75 °C for 6 h, and finally washing several times with acetone and drying at 60 °C for 12 h to obtain the quaternary ammonium salt antibacterial agent.

[0009] Preferably, the structural formula of the quaternary ammonium salt antibacterial agent is

[0010]

[0011] n = 11, 13, 15, 17.

[0012] Preferably, the acrylate monomer is selected from at least one of methyl acrylate, ethyl acrylate, butyl acrylate, and methyl methacrylate; the initiator is selected from ammonium persulfate; the crosslinking agent is selected from N,N'-methylenebisacrylamide; the composite emulsifier is composed of ammonium 1-allyloxy-3-(4-nonylphenol)-2-propanol polyoxyethylene (10) ether sulfate and alkylphenol polyoxyethylene ether with a mass ratio of 2:1; the first pH regulator is selected from one or more of ammonia water, triethylamine, triethanolamine, and N,N-dimethylethanolamine.

[0013] Preferably, by weight, it is composed of 65 - 80 parts by weight of the acrylic emulsion, 10 - 15 parts by weight of deionized water, 0.5 - 0.7 parts by weight of a thickener, 0.5 - 0.7 parts by weight of a second pH regulator, 0.1 - 1 part by weight of a flash rust inhibitor, and 0.4 - 0.6 parts by weight of an antifoaming agent.

[0014] Preferably, the thickener is a urethane associative thickener; the second pH regulator is selected from one or more of ammonia water, triethylamine, triethanolamine, and N,N-dimethylethanolamine; the flash rust inhibitor is a modified macromolecular organic amine flash rust inhibitor; the antifoaming agent is a silicone antifoaming agent.

[0015] On the other hand, the present invention provides a preparation method of the antibacterial and antifogging coating according to any one of the above technical solutions, including a step of preparing an acrylic emulsion, and the step of preparing the acrylic emulsion sequentially includes the preparation of a pre-emulsion, emulsion polymerization, and a holding stage.

[0016] Preferably, the preparation of the pre-emulsion includes: adding a part of the quaternary ammonium salt antibacterial agent, a part of N-vinylpyrrolidone, and a composite emulsifier to deionized water, and stirring to dissolve them to obtain a pre-emulsion;

[0017] The emulsion polymerization includes: preparing a mixed solution composed of acrylic acid, acrylamide, acrylate, the remaining quaternary ammonium salt antibacterial agent, the remaining N-vinylpyrrolidone, a cross-linking agent and deionized water for standby. Under a nitrogen atmosphere, 1 / 5 of the pre-emulsion is used as a primer and heated in a water bath at 80°C, and an aqueous solution containing an initiator is added dropwise. After the solution turns blue, the above-prepared mixed solution and the remaining 4 / 5 of the pre-emulsion are added dropwise, and the whole process is continuously stirred and refluxed for reaction;

[0018] The heat preservation stage includes: after the reactants are added dropwise, the temperature of the mixed emulsion is raised to 85-90°C for heat preservation. After the heat preservation ends, it is naturally cooled to a temperature below 50°C, and the pH is adjusted to 7-8 with a pH regulator. Finally, it is filtered through a 100-mesh metal filter to obtain the acrylic emulsion.

[0019] The present invention also provides a refrigerator, on the aluminum alloy air duct decorative plate of which the antibacterial and anti-fog coating described in any of the above technical solutions is coated.

[0020] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0021] The present invention provides an antibacterial and anti-fog coating. The acrylic emulsion is copolymerized from acrylic acid, acrylamide, acrylate, a quaternary ammonium salt antibacterial agent and N-vinylpyrrolidone. Among them, the introduction of the quaternary ammonium salt antibacterial agent realizes the antibacterial function of the emulsion, and the introduction of N-vinylpyrrolidone improves the hydrophilicity of the emulsion. The prepared coating has excellent antibacterial and anti-fog properties; specifically, the quaternary ammonium salt antibacterial agent contains a positively charged quaternary amine group, which can rupture the cell membrane of bacteria and cause bacteria to die. However, the hydrophobic alkyl group of the quaternary ammonium salt antibacterial agent reduces the hydrophilicity of the coating. By introducing N-vinylpyrrolidone for copolymerization modification, the hydrophilicity of the antibacterial and anti-fog coating is improved, ensuring the overall effect of the antibacterial and anti-fog coating. Specific embodiments

[0022] The technical solutions in the specific embodiments of the present invention will be described in detail and completely below. Obviously, the described embodiments are only partial specific embodiments of the general technical solution of the present invention, rather than all embodiments. Based on the general concept of the present invention, all other embodiments obtained by those of ordinary skill in the art fall within the protection scope of the present invention.

[0023] On the one hand, the present invention provides an antibacterial and antifogging coating, comprising an acrylic emulsion, and the acrylic emulsion includes: acrylic monomers, acrylamide monomers, acrylate monomers, quaternary ammonium salt antibacterial agents, N-vinylpyrrolidone, crosslinking agents, initiators, composite emulsifiers, and a first pH regulator; the quaternary ammonium salt antibacterial agent is prepared by the following method: adding alkyl dimethyl tertiary amine and 3-chloropropene into an ethanol solution of the same mass, heating and stirring under reflux, and finally washing with acetone and drying to obtain the quaternary ammonium salt antibacterial agent. The acrylic emulsion is copolymerized from acrylic acid, acrylamide, acrylate, quaternary ammonium salt antibacterial agent, and N-vinylpyrrolidone. Among them, the introduction of the quaternary ammonium salt antibacterial agent realizes the antibacterial function of the emulsion, and the introduction of N-vinylpyrrolidone improves the hydrophilicity of the emulsion. The prepared coating has excellent antibacterial and antifogging properties; specifically, the quaternary ammonium salt antibacterial agent contains a positively charged quaternary amine group, which can rupture the cell membrane of bacteria, resulting in the death of bacteria. However, the hydrophobic alkyl group of the quaternary ammonium salt antibacterial agent reduces the hydrophilicity of the coating. By introducing N-vinylpyrrolidone for copolymerization modification, the hydrophilicity of the antibacterial and antifogging coating is improved, ensuring the overall effect of the antibacterial and antifogging coating.

[0024] In a preferred embodiment, by weight parts, the acrylic emulsion consists of 10 - 25 parts by weight of acrylic monomers, 10 - 25 parts by weight of acrylamide monomers, 12 - 30 parts by weight of acrylate monomers, 46 - 115 parts by weight of quaternary ammonium salt antibacterial agent, 16 - 40 parts by weight of N-vinylpyrrolidone, 20 - 50 parts by weight of crosslinking agent, 0.1 - 1 part by weight of initiator, 0.5 - 5 parts by weight of composite emulsifier, 140 - 200 parts by weight of deionized water, and 0.5 - 5 parts by weight of the first pH regulator. This technical solution specifically defines the dosages of each component. It can be understood that the dosage of acrylic monomers can also be 12 parts, 14 parts, 16 parts, 18 parts, 20 parts, 22 parts, 24 parts and any point value within this range; the dosage of acrylamide monomers can also be 12 parts, 14 parts, 16 parts, 18 parts, 20 parts, 22 parts, 24 parts and any point value within this range; the dosage of acrylate monomers can also be 14 parts, 16 parts, 18 parts, 20 parts, 22 parts, 24 parts, 26 parts, 28 parts and any point value within this range; the dosage of quaternary ammonium salt antibacterial agent can also be 50 parts, 60 parts, 70 parts, 80 parts, 90 parts, 100 parts, 110 parts and any point value within this range; the dosage of N-vinylpyrrolidone can also be 20 parts, 25 parts, 30 parts, 35 parts and any point value within this range; the dosage of crosslinking agent can also be 25 parts, 30 parts, 35 parts, 40 parts, 45 parts and any point value within this range; the dosage of initiator can also be 0.2 parts, 0.4 parts, 0.6 parts, 0.8 parts and any point value within this range; the dosage of composite emulsifier can also be 1 part, 2 parts, 3 parts, 4 parts and any point value within this range; the dosage of deionized water can also be 150, 160, 170, 180, 190 parts and any point value within this range; the dosage of the first pH regulator can also be 1, 2, 3, 4 and any point value within this range.

[0025] In a preferred embodiment, the quaternary ammonium salt antibacterial agent is prepared by the following method: Add alkyl dimethyl tertiary amine and 3-chloropropene with a mass molar ratio of 1:1.05 to an ethanol solution of the same mass, stir and reflux at 75°C for 6 h, and finally wash several times with acetone and dry at 60°C for 12 h to obtain the quaternary ammonium salt antibacterial agent. During this preparation process, ethanol is used as the reaction solvent. Alkyl dimethyl tertiary amine and 3-chloropropene are insoluble in water but can dissolve in ethanol for reaction. Ethanol of the same mass can ensure the complete dissolution of the two substances.

[0026] In a preferred embodiment, the structural formula of the quaternary ammonium salt antibacterial agent is

[0027]

[0028] n = 11, 13, 15, 17. This technical solution specifically defines the structural formula of the quaternary ammonium salt antibacterial agent. The reason is that such quaternary ammonium salts contain carbon-carbon double bonds and can undergo copolymerization reactions with acrylic acid monomers, acrylamide monomers, and acrylate monomers.

[0029] In a preferred embodiment, the acrylate monomer is selected from at least one of methyl acrylate, ethyl acrylate, butyl acrylate, and methyl methacrylate; the initiator is selected from ammonium persulfate; the crosslinking agent is selected from N,N'-methylenebisacrylamide; the composite emulsifier is composed of ammonium 1-allyloxy-3-(4-nonylphenol)-2-propanol polyoxyethylene (10) ether sulfate and alkylphenol polyoxyethylene ether with a mass ratio of 2:1; the first pH regulator is selected from one or more of ammonia water, triethylamine, triethanolamine, and N,N-dimethylethanolamine.

[0030] In a preferred embodiment, by weight, it is composed of 65 - 80 parts by weight of the acrylic emulsion, 10 - 15 parts by weight of deionized water, 0.5 - 0.7 parts by weight of a thickener, 0.5 - 0.7 parts by weight of a second pH regulator, 0.1 - 1 part by weight of a flash rust inhibitor, and 0.4 - 0.6 parts by weight of an antifoaming agent. For the specific amounts of the components in this technical solution, it can be understood that the amount of the acrylic emulsion can also be 70 parts, 75 parts, and any point value within this range; the amount of deionized water can also be 11 parts, 12 parts, 13 parts, 14 parts, and any point value within this range; the amount of the thickener can also be 0.6 parts and any point value within this range; the amount of the second pH regulator can also be 0.6 parts and any point value within this range; the amount of the flash rust inhibitor can also be 0.2 parts, 0.4 parts, 0.6 parts, 0.8 parts, and any point value within this range; the amount of the antifoaming agent can also be 0.5 parts and any point value within this range.

[0031] In a preferred embodiment, the thickener is an ethyl carbamate associative thickener; the second pH regulator is selected from one or more of ammonia water, triethylamine, triethanolamine, and N,N-dimethylethanolamine; the flash rust inhibitor is a modified macromolecular organic amine-based flash rust inhibitor; the antifoaming agent is a silicone antifoaming agent.

[0032] On the other hand, the present invention provides a preparation method of the antibacterial and antifogging coating according to any of the above technical solutions, including a step for preparing an acrylic emulsion, and the step for preparing the acrylic emulsion sequentially includes the preparation of a pre-emulsion, emulsion polymerization, and a holding stage.

[0033] In a preferred embodiment, the preparation of the pre-emulsion includes: adding a part of quaternary ammonium salt antibacterial agent, a part of N-vinylpyrrolidone and a composite emulsifier to deionized water, and stirring to dissolve them to obtain the pre-emulsion; in this preparation process, the pre-emulsion is prepared first because, for the stability of the synthesis reaction, if pre-emulsification is not carried out and the monomers are directly subjected to polymerization reaction, a gel effect is likely to occur.

[0034] The emulsion polymerization includes: preparing a mixed solution composed of acrylic acid, acrylamide, acrylate, the remaining quaternary ammonium salt antibacterial agent, the remaining N-vinylpyrrolidone, a cross-linking agent and deionized water for standby. Under a nitrogen atmosphere, 1 / 5 of the pre-emulsion is used as a primer and heated in a water bath at 80 °C, and an aqueous solution containing an initiator is added dropwise. After the solution turns blue, the above-prepared mixed solution and the remaining 4 / 5 of the pre-emulsion are added dropwise. The whole process is continuously stirred and refluxed; this step also defines adding the pre-emulsion in two steps and the relationship of the addition amounts. The reason is that the seed emulsion polymerization method can obtain polymers with different structures and excellent performance stability. Compared with ordinary emulsion polymerization, it has more excellent performance in terms of rheology, adhesiveness, etc. Adding the emulsifier as a primer for the first time is to avoid the gel effect; adding the emulsion for the second time is to control the reaction rate and the latex particle size. By adding the pre-emulsion dropwise, no new latex particles will be generated during the polymerization process, the rate of the polymerization reaction will no longer change, the polymerization reaction can proceed continuously, and the latex particle size is small and the rheology is good.

[0035] The heat preservation stage includes: after the reactants are added dropwise, raising the temperature of the mixed emulsion to 85 - 90 °C for heat preservation. After the heat preservation is completed, it is naturally cooled to the emulsion temperature below 50 °C, and the pH is adjusted to 7 - 8 with a pH regulator, and finally filtered through a 100-mesh metal filter screen to obtain the acrylic emulsion.

[0036] The present invention also provides a refrigerator, on the aluminum alloy air duct decorative plate of which the antibacterial and anti-fog coating described in any of the above technical solutions is coated. When the refrigerator door is opened, there will be no fogging, and at the same time, it also has a lasting antibacterial property.

[0037] In order to introduce the antibacterial and anti-fog coating, its preparation method and the refrigerator provided by the embodiments of the present invention more clearly and in detail, the following will be described in combination with specific embodiments.

[0038] (1) Preparation of acrylic emulsion

[0039] Example 1

[0040] The preparation method of the acrylic emulsion includes the following steps:

[0041] (1) Weigh 20 parts by weight of quaternary ammonium salt antibacterial agent, 7 parts by weight of N-vinylpyrrolidone, and 0.5 part by weight of compound emulsifier, add them to 60 parts by weight of deionized water, stir to dissolve them, with a stirring speed of 1000 - 1200 r / min, and emulsify for 30 min to prepare a pre-emulsion.

[0042] (2) Emulsion polymerization

[0043] Prepare a mixed solution composed of 10 parts by weight of acrylic acid, 10 parts by weight of acrylamide, 12 parts by weight of acrylate, 26 parts by weight of quaternary ammonium salt antibacterial agent, 9 parts by weight of N-vinylpyrrolidone, 20 parts by weight of crosslinking agent, and 80 parts by weight of deionized water for standby. Under a nitrogen atmosphere, take 1 / 5 of the pre-emulsion in step (1) as a primer, heat it in a water bath at 80 °C, and gradually dropwise add an aqueous solution containing 0.1 part by weight of initiator. After 15 min, the solution turns blue, and then start to gradually dropwise add the above-prepared mixed solution and the remaining 4 / 5 of the pre-emulsion. Stir and reflux the reaction for 1 h throughout the process.

[0044] (3) Heat preservation stage

[0045] After the reactants are added dropwise, raise the temperature of the mixed emulsion to 85 - 90 °C and keep it warm for 1 h. After the heat preservation is completed, naturally cool it until the emulsion temperature is below 50 °C, adjust the pH to 7 - 8 with 0.5 part by weight of pH regulator, and finally filter it through a 100-mesh metal filter to obtain the acrylic emulsion.

[0046] Example 2

[0047] A preparation method of acrylic emulsion, comprising the following steps:

[0048] (1) Weigh 30 parts by weight of quaternary ammonium salt antibacterial agent, 10 parts by weight of N-vinylpyrrolidone, and 1.5 parts by weight of compound emulsifier, add them to 70 parts by weight of deionized water, stir to dissolve them, with a stirring speed of 1000 - 1200 r / min, and emulsify for 30 min to prepare a pre-emulsion.

[0049] (2) Emulsion polymerization

[0050] Prepare a mixed solution composed of 15 parts by weight of acrylic acid, 15 parts by weight of acrylamide, 18 parts by weight of acrylate, 39 parts by weight of quaternary ammonium salt antibacterial agent, 14 parts by weight of N-vinylpyrrolidone, 30 parts by weight of crosslinking agent, and 90 parts by weight of deionized water for standby. Under a nitrogen atmosphere, take 1 / 5 of the pre-emulsion in step (1) as a primer, heat it in a water bath at 80 °C, and gradually dropwise add an aqueous solution containing 0.4 part by weight of initiator. After 15 min, the solution turns blue, and then start to gradually dropwise add the above-prepared mixed solution and the remaining 4 / 5 of the pre-emulsion. Stir and reflux the reaction for 1 h throughout the process.

[0051] (3) Heat preservation stage

[0052] After the reactants are completely added dropwise, raise the temperature of the mixed emulsion to 85 - 90 °C and keep it warm for 1 h. After the heat preservation is completed, naturally cool it to below 50 °C of the emulsion temperature, adjust the pH to 7 - 8 with 2 parts by weight of pH regulator, and finally filter it with a 100 - mesh metal filter screen to obtain the acrylic emulsion.

[0053] Example 3

[0054] A method for preparing an acrylic emulsion, comprising the following steps:

[0055] (1) Weigh 40 parts by weight of quaternary ammonium salt antibacterial agent, 14 parts by weight of N - vinylpyrrolidone, and 4 parts by weight of composite emulsifier, add them to 80 parts by weight of deionized water, stir to dissolve them, with a stirring speed of 1000 - 1200 r / min, and emulsify for 30 min to prepare a pre - emulsion.

[0056] (2) Emulsion polymerization

[0057] Prepare a mixed solution composed of 20 parts by weight of acrylic acid, 20 parts by weight of acrylamide, 24 parts by weight of acrylate, 52 parts by weight of quaternary ammonium salt antibacterial agent, 18 parts by weight of N - vinylpyrrolidone, 40 parts by weight of cross - linker and 100 parts by weight of deionized water for standby. Under a nitrogen atmosphere, take 1 / 5 of the pre - emulsion in step (1) as the primer, heat it in a water bath at 80 °C, and gradually add dropwise an aqueous solution containing 0.8 parts by weight of initiator. After 15 min, the solution turns blue, and then gradually add dropwise the above - prepared mixed solution and the remaining 4 / 5 of the pre - emulsion, and continuously stir and reflux for 1 h during the whole process.

[0058] (3) Heat preservation stage

[0059] After the reactants are completely added dropwise, raise the temperature of the mixed emulsion to 85 - 90 °C and keep it warm for 1 h. After the heat preservation is completed, naturally cool it to below 50 °C of the emulsion temperature, adjust the pH to 7 - 8 with 4 parts by weight of pH regulator, and finally filter it with a 100 - mesh metal filter screen to obtain the acrylic emulsion.

[0060] Comparative Example 1

[0061] A method for preparing an acrylic emulsion, comprising the following steps:

[0062] (1) Weigh 7 parts by weight of N - vinylpyrrolidone and 0.5 parts by weight of composite emulsifier, add them to 60 parts by weight of deionized water, stir to dissolve them, with a stirring speed of 1000 - 1200 r / min, and emulsify for 30 min to prepare a pre - emulsion.

[0063] (2) Emulsion polymerization

[0064] Prepare a mixed solution composed of 10 parts by weight of acrylic acid, 10 parts by weight of acrylamide, 12 parts by weight of acrylate, 9 parts by weight of N-vinylpyrrolidone, 20 parts by weight of crosslinking agent and 80 parts by weight of deionized water for standby. Under a nitrogen atmosphere, take 1 / 5 of the pre-emulsion in step (1) as the base, heat it in a water bath at 80 °C, and dropwise add an aqueous solution containing 0.1 part by weight of initiator. After 15 minutes, the solution turns blue, and then start to dropwise add the above-prepared mixed solution and the remaining 4 / 5 of the pre-emulsion. Stir and reflux the reaction for 1 hour throughout the process.

[0065] (3) Heat preservation stage

[0066] After the reactants are added dropwise, raise the temperature of the mixed emulsion to 85 - 90 °C and keep it warm for 1 hour. After the heat preservation is completed, naturally cool it to a temperature below 50 °C, adjust the pH to 7 - 8 with 0.5 part by weight of pH regulator, and finally filter it through a 100-mesh metal filter to obtain the acrylic emulsion.

[0067] Comparative Example 2

[0068] A preparation method of an acrylic emulsion, comprising the following steps:

[0069] (1) Weigh 20 parts by weight of quaternary ammonium salt antibacterial agent and 0.5 part by weight of composite emulsifier, add them to 60 parts by weight of deionized water, stir to dissolve them, with a stirring speed of 1000 - 1200 r / min, and emulsify for 30 minutes to prepare a pre-emulsion.

[0070] (2) Emulsion polymerization

[0071] Prepare a mixed solution composed of 10 parts by weight of acrylic acid, 10 parts by weight of acrylamide, 12 parts by weight of acrylate, 26 parts by weight of quaternary ammonium salt antibacterial agent, 20 parts by weight of crosslinking agent and 80 parts by weight of deionized water for standby. Under a nitrogen atmosphere, take 1 / 5 of the pre-emulsion in step (1) as the base, heat it in a water bath at 80 °C, and dropwise add an aqueous solution containing 0.1 part by weight of initiator. After 15 minutes, the solution turns blue, and then start to dropwise add the above-prepared mixed solution and the remaining 4 / 5 of the pre-emulsion. Stir and reflux the reaction for 1 hour throughout the process.

[0072] (3) Heat preservation stage

[0073] After the reactants are added dropwise, raise the temperature of the mixed emulsion to 85 - 90 °C and keep it warm for 1 hour. After the heat preservation is completed, naturally cool it to a temperature below 50 °C, adjust the pH to 7 - 8 with 0.5 part by weight of pH regulator, and finally filter it through a 100-mesh metal filter to obtain the acrylic emulsion.

[0074] Comparative Example 3

[0075] A preparation method of an acrylic emulsion, comprising the following steps:

[0076] (1) Weigh 0.5 parts by weight of the composite emulsifier and add it to 60 parts by weight of deionized water. Stir to dissolve it, with a stirring speed of 1000 - 1200 r / min, and emulsify for 30 min to obtain a pre-emulsion.

[0077] (2) Emulsion polymerization

[0078] Prepare a mixed solution composed of 10 parts by weight of acrylic acid, 10 parts by weight of acrylamide, 12 parts by weight of acrylate, 20 parts by weight of crosslinking agent and 80 parts by weight of deionized water for standby. Under a nitrogen atmosphere, take 1 / 5 of the pre-emulsion in step (1) as the primer, heat it in a water bath at 80 °C, and gradually dropwise add an aqueous solution containing 0.1 part by weight of initiator. After 15 min, the solution turns blue, and then gradually dropwise add the above-prepared mixed solution and the remaining 4 / 5 of the pre-emulsion. Stir and reflux the reaction for 1 h throughout the process.

[0079] (3) Heat preservation stage

[0080] After the reactants are completely added, raise the temperature of the mixed emulsion to 85 - 90 °C and keep it warm for 1 h. After the heat preservation is completed, naturally cool it to a temperature below 50 °C for the emulsion, and adjust the pH to 7 - 8 with 0.5 part by weight of pH regulator. Finally, filter it through a 100-mesh metal filter screen to obtain the acrylic emulsion.

[0081] (II) Preparation of antibacterial and antifogging coating

[0082] Example 4

[0083] Mix 65 parts by weight of the acrylic emulsion in Example 1, 10 parts by weight of deionized water, 0.1 part by weight of anti-flash rust agent, 0.4 part by weight of defoamer, 0.5 part by weight of pH regulator, and 0.5 part by weight of thickener, and stir for 30 min to make it uniformly mixed to obtain the coating.

[0084] Example 5

[0085] Mix 70 parts by weight of the acrylic emulsion in Example 2, 12 parts by weight of deionized water, 0.3 part by weight of anti-flash rust agent, 0.5 part by weight of defoamer, 0.6 part by weight of pH regulator, and 0.6 part by weight of thickener, and stir for 30 min to make it uniformly mixed to obtain the coating.

[0086] Example 6

[0087] Mix 80 parts by weight of the acrylic emulsion in Example 3, 15 parts by weight of deionized water, 1 part by weight of anti-flash rust agent, 0.6 part by weight of defoamer, 0.7 part by weight of pH regulator, and 0.7 part by weight of thickener, and stir for 30 min to make it uniformly mixed to obtain the coating.

[0088] Comparative Example 4

[0089] Mix 65 parts by weight of the acrylic emulsion of Comparative Example 1, 10 parts by weight of deionized water, 0.1 part by weight of anti-corrosion agent for preventing flash rust, 0.4 part by weight of defoamer, 0.5 part by weight of pH regulator, and 0.5 part by weight of thickener, and stir for 30 min to make the mixture uniform, thereby preparing a coating material.

[0090] Comparative Example 5

[0091] Mix 65 parts by weight of the acrylic emulsion of Comparative Example 2, 10 parts by weight of deionized water, 0.1 part by weight of anti-corrosion agent for preventing flash rust, 0.4 part by weight of defoamer, 0.5 part by weight of pH regulator, and 0.5 part by weight of thickener, and stir for 30 min to make the mixture uniform, thereby preparing a coating material.

[0092] Comparative Example 6

[0093] Mix 65 parts by weight of the acrylic emulsion of Comparative Example 3, 10 parts by weight of deionized water, 0.1 part by weight of anti-corrosion agent for preventing flash rust, 0.4 part by weight of defoamer, 0.5 part by weight of pH regulator, and 0.5 part by weight of thickener, and stir for 30 min to make the mixture uniform, thereby preparing a coating material.

[0094] Performance Test

[0095] The antibacterial rates of the coating materials prepared in Examples 4 - 6 and Comparative Examples 4 - 6 were determined according to GB / T 21510 - 2008. The coating materials prepared in Examples 4 - 6 and Comparative Examples 4 - 6 were applied to a metal substrate, left to dry at room temperature to form a film, and the contact angle of the coating was measured using a water contact angle tester. According to the requirements of GB / T 31726 - 2015, a thermal fog experiment was carried out. The coating sample was placed 20 s above hot water at 80 °C, and the anti-fogging effect of the coating was observed. The test results are shown in Table 1.

[0096] Table 1 Test Results

[0097]

[0098]

[0099] As can be seen from the above table, the antibacterial and anti-fogging coating prepared by the present invention has a high antibacterial rate and a low water contact angle, and at the same time exhibits excellent anti-fogging performance.

Claims

1. An antibacterial and anti-fog coating, characterized in that, It includes an acrylic emulsion, and the acrylic emulsion includes: acrylic monomers, acrylamide monomers, acrylate monomers, quaternary ammonium salt antibacterial agents, N-vinylpyrrolidone, crosslinking agents, initiators, composite emulsifiers, and a first pH regulator; the quaternary ammonium salt antibacterial agent is prepared by the following method: Alkyl dimethyl tertiary amine and 3-chloropropene are added to an ethanol solution of the same mass, heated and stirred under reflux, and finally washed with acetone and then dried to prepare the quaternary ammonium salt antibacterial agent.

2. The antibacterial and anti-fog coating according to claim 1, characterized in that By weight, the acrylic emulsion consists of 10-25 parts by weight of acrylic monomers, 10-25 parts by weight of acrylamide monomers, 12-30 parts by weight of acrylate monomers, 46-115 parts by weight of quaternary ammonium salt antibacterial agents, 16-40 parts by weight of N-vinylpyrrolidone, 20-50 parts by weight of crosslinking agents, 0.1-1 part by weight of initiators, 0.5-5 parts by weight of composite emulsifiers, 140-200 parts by weight of deionized water, and 0.5-5 parts by weight of the first pH regulator.

3. The antibacterial and antifogging coating according to claim 1, wherein The quaternary ammonium salt antibacterial agent is prepared by the following method: Alkyl dimethyl tertiary amine and 3-chloropropene with a mass molar ratio of 1:1.05 are added to an ethanol solution of the same mass, stirred and refluxed at 75°C for 6 h, and finally washed several times with acetone and dried at 60°C for 12 h to prepare the quaternary ammonium salt antibacterial agent.

4. The antibacterial and anti-fog coating according to claim 1, wherein The structural formula of the quaternary ammonium salt antibacterial agent is n＝11，13，15，17。 5. The antibacterial and anti-fog coating according to claim 1, wherein The acrylate monomer is selected from at least one of methyl acrylate, ethyl acrylate, butyl acrylate, and methyl methacrylate; the initiator is selected from ammonium persulfate; the crosslinking agent is selected from N,N'-methylenebisacrylamide; the composite emulsifier consists of ammonium 1-allyloxy-3-(4-nonylphenol)-2-propanol polyoxyethylene (10) ether sulfate and alkylphenol polyoxyethylene ether with a mass ratio of 2:1; the first pH regulator is selected from one or more of ammonia water, triethylamine, triethanolamine, and N,N-dimethylethanolamine.

6. The antibacterial and anti-fog coating according to claim 1, wherein By weight, it consists of 65-80 parts by weight of the acrylic emulsion, 10-15 parts by weight of deionized water, 0.5-0.7 part by weight of a thickener, 0.5-0.7 part by weight of a second pH regulator, 0.1-1 part by weight of a flash rust inhibitor, and 0.4-0.6 part by weight of an antifoaming agent.

7. The antibacterial and anti-fog coating according to claim 6, characterized in that, The thickener is an ethyl carbamate associative thickener; the second pH regulator is selected from one or more of ammonia water, triethylamine, triethanolamine, and N,N-dimethylethanolamine; the flash rust inhibitor is a modified macromolecular organic amine type flash rust inhibitor; the antifoaming agent is a silicone antifoaming agent.

8. The preparation method of the antibacterial and anti-fog coating according to any one of claims 1-7, characterized in that, It includes the preparation steps of the acrylic emulsion, and the preparation steps of the acrylic emulsion successively include the preparation of a pre-emulsion, emulsion polymerization, and a heat preservation stage.

9. The preparation method of the antibacterial and anti-fog coating according to claim 8, wherein, The preparation of the pre-emulsion includes: adding part of the quaternary ammonium salt antibacterial agent, part of N-vinylpyrrolidone, and a composite emulsifier to deionized water, stirring to dissolve them, and preparing a pre-emulsion; The emulsion polymerization includes: preparing a mixed solution composed of acrylic acid, acrylamide, acrylate, the remaining quaternary ammonium salt antibacterial agent, the remaining N-vinyl pyrrolidone, a cross-linking agent and deionized water. Under a nitrogen atmosphere, 1 / 5 of the pre-emulsion is used as a primer and heated in a water bath at 80 °C, and an aqueous solution containing an initiator is added dropwise. After the solution turns blue, the above-prepared mixed solution and the remaining 4 / 5 of the pre-emulsion are added dropwise, and the whole process is continuously stirred and refluxed. The heat preservation stage includes: after the addition of the reactants is completed, the temperature of the mixed emulsion is raised to 85 - 90 °C for heat preservation. After the heat preservation is completed, it is naturally cooled to a temperature below 50 °C, and the pH is adjusted to 7 - 8 with a pH regulator. Finally, it is filtered through a 100-mesh metal filter screen to obtain the acrylic emulsion.

10. A refrigerator, characterized in that, The antibacterial and anti-fog coating according to any one of claims 1 - 7 is coated on the aluminum alloy air duct decorative plate of the refrigerator.

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