Environment-friendly paint with antibacterial effect and preparation method thereof

Abstract

The invention relates to the technical field of paint. The environment-friendly paint is prepared from the following raw materials in parts by weight: 30 to 50 parts of waterborne acrylic resin, 20 to 30 parts of deionized water, 8 to 10 parts of diatomite, 5 to 7 parts of bamboo charcoal powder, 3 to 5 parts of coalescing agent, 3 to 5 parts of modified eggshell powder, 2 to 3 parts of dispersing agent, 2 to 3 parts of thickening agent and 2 to 3 parts of sodium alginate-chitosan compound. 1-2 parts of a nano-silver antibacterial agent and 1-2 parts of a defoaming agent. According to the environment-friendly paint, chitosan is combined with negatively charged bacterial cell membranes by virtue of positive charges, the membrane structure is destroyed to cause intracellular substance leakage, and the space structure of the compound hinders nutrient uptake of bacteria and waste discharge, so that the antibacterial property of the environment-friendly paint can be remarkably improved.

Description

Technical Field

[0001] The invention relates to the technical field of paints, in particular to an environmentally friendly paint with antibacterial effect and a preparation method thereof. Background Art

[0002] Paint is a chemical mixture coating that can firmly cover the surface of an object for protection, decoration, marking and other special purposes. This material can be applied to the surface of an object using different construction techniques to form a solid film that is firmly adhered, has a certain strength, and is continuous. The film formed in this way is generally called a coating film, also known as a paint film or coating.

[0003] The main components of traditional paints are resins, pigments, solvents and additives. These components themselves do not have antibacterial properties and cannot directly inhibit or kill microorganisms such as bacteria and fungi. They are not stable enough under complex conditions. Therefore, in response to the above problems, a new type of environmentally friendly paint with antibacterial effect and a preparation method thereof are proposed. Summary of the invention

[0004] The purpose of the present invention is to provide an environmentally friendly paint with antibacterial effect and a preparation method thereof. The environmentally friendly paint with antibacterial effect prepared by the present invention has good antibacterial performance and good wear resistance, and the entire formula is green and environmentally friendly.

[0005] To achieve the above purpose, the present invention provides the following technical scheme: an environmentally friendly paint with antibacterial effect, comprising the following raw materials in parts by weight: 30-50 parts of water-based acrylic resin, 20-30 parts of deionized water, 8-10 parts of diatomaceous earth, 5-7 parts of bamboo charcoal powder, 3-5 parts of film-forming aid, 3-5 parts of modified eggshell powder, 2-3 parts of dispersant, 2-3 parts of thickener, 2-3 parts of sodium alginate-chitosan complex, 1-2 parts of nano silver antibacterial agent, and 1-2 parts of defoaming agent.

[0006] Preferably, the solid content of the aqueous acrylic resin is (40-60)%, and the particle size of the nano-silver antibacterial agent is 20-40 nm.

[0007] Preferably, the film-forming aid can be at least one of alcohol ester-12, propylene glycol phenyl ether and diethylene glycol butyl ether, and the dispersant can be at least one of polycarboxylate dispersants, alkyl naphthalene sulfonate dispersants and fatty acid polyoxyethylene ether dispersants.

[0008] Preferably, the defoamer can be at least one of an organosilicon defoamer, a polyether defoamer and a mineral oil defoamer, and the thickener can be at least one of hydroxyethyl cellulose, a polyurethane thickener or a polyacrylic thickener.

[0009] Preferably, the modified eggshell powder is prepared by the following method: fresh eggshells are selected as raw materials, washed with clean water, and then surface impurities and inner membranes are removed, and then placed in an oven to dry to obtain dry eggshells, and then placed in a ball mill to grind to obtain eggshell powder, and then the eggshell powder is placed in an acetic acid solution, heated to 40-60°C, and continuously stirred at 40-60r / min for 1-2h, and then filtered to obtain a crude modified eggshell powder, and then washed with ionized water until neutral, and then placed in an oven for drying to obtain the modified eggshell powder.

[0010] Through the above technical scheme, calcium carbonate, the main component of eggshell powder, is modified with acetic acid to generate calcium acetate on the surface, which changes the surface charge and chemical activity. On the one hand, calcium acetate and the like can ionize into Ca²⁺, which has a high charge density and can interact with the negatively charged phospholipid molecules on the surface of bacterial cell membranes, destroying the integrity and fluidity of the cell membranes, leading to leakage of intracellular substances, and thereby inhibiting bacterial growth and reproduction. On the other hand, the modification process promotes the release of proteins such as lysozyme, a potential antibacterial component in eggshell powder. Lysozyme can hydrolyze the peptidoglycan component of the bacterial cell wall, destroy the cell wall structure, and cause the bacteria to die due to osmotic pressure imbalance. In addition, in the paint system, the modified eggshell powder and the nanosilver antibacterial agent work synergistically. Nanosilver can combine with bacterial enzymes, nucleic acids and other biomacromolecules to interfere with bacterial metabolism and genetic information transmission, and work together with the modified eggshell powder from different chemical pathways to comprehensively enhance the antibacterial properties of the paint.

[0011] Preferably, during the preparation of the modified eggshell powder, the temperature of the oven is set at 100-120°C, the baking time is 2-3h, the speed of the ball mill is set to 200-300r / min, the grinding time is 2-3h, the eggshell powder particle size is 50-100 mesh, and the acetic acid solution is prepared by mixing acetic acid and water in a mass ratio of 1:19.

[0012] Preferably, the sodium alginate-chitosan complex is prepared by the following method: selecting a sodium alginate solution and a chitosan solution, wherein the mass ratio of the sodium alginate solution to the chitosan solution is 1:(1-2), heating the sodium alginate solution to 30-40°C, and continuously stirring at 100-200 r / min, during which the chitosan solution is added dropwise at a dropping speed of 1-2 drops / second, and after the addition is completed, continuously stirring at 200-300 r / min for 1-2 hours to obtain a sodium alginate-chitosan complex.

[0013] Through the above technical solution: negatively charged sodium alginate and positively charged chitosan form a complex through electrostatic interaction. The formation of this complex changes the molecular structure and charge distribution, enhances the adsorption capacity of bacteria, allows more bacteria to contact the complex, and improves the antibacterial effect. On the other hand, the complex can form a physical barrier on the surface of bacteria, hindering bacteria from obtaining nutrients and excreting metabolic waste, inhibiting the growth and reproduction of bacteria. In addition, the active groups contained in sodium alginate and chitosan themselves may act synergistically after the formation of the complex, further interfering with the physiological metabolic process of bacteria, such as affecting the activity of bacterial enzymes, thereby comprehensively improving the antibacterial performance.

[0014] Preferably, the sodium alginate solution is prepared by the following method: weigh sodium alginate agglomerates and deionized water as needed, the mass ratio of the sodium alginate agglomerates to deionized water is 3:97, add deionized water and sodium alginate agglomerates into a mixer, set the speed to 100-200r / min, and continue stirring for 30-60min to obtain a sodium alginate solution.

[0015] Through the above technical scheme: Sodium alginate is a linear polysaccharide formed by connecting β-D-mannuronic acid and α-L-guluronic acid through 1,4-glycosidic bonds, and has polyanionic properties. When prepared alone, the carboxyl groups in its molecules can be partially ionized, so that sodium alginate has a negative charge.

[0016] Preferably, the chitosan solution is prepared by the following method: weigh acetic acid, chitosan and deionized water in a mass ratio of 2:3:95 as required, add acetic acid and deionized water into a mixer, set the speed to 100-150r / min, continue stirring for 30-60min to obtain a first solution, then add chitosan, increase the speed to 200-300r / min, continue stirring for 1-2h to obtain a chitosan solution.

[0017] Through the above technical scheme: Chitosan is a linear polysaccharide obtained by deacetylation of chitin. It contains a large number of amino groups in the molecule and is protonated with a positive charge under acidic conditions. This cationic property makes it easy to interact with the negatively charged bacterial cell membrane, destroying the integrity of the cell membrane, causing leakage of intracellular substances, and thus inhibiting bacterial growth.

[0018] Furthermore, a method for preparing an environmentally friendly paint having an antibacterial effect comprises the following steps: S1: Weigh deionized water as needed and add it into the reactor. Start the reactor and continue stirring at a stirring speed of 300-500r / min. Then add dispersant and defoamer in sequence and continue stirring for 20-30min. S2: Weigh diatomaceous earth and bamboo charcoal powder as needed and add them into the reactor in S1, increase the stirring speed to 800-1000r / min, continue stirring for 30-40min, then add nano-silver antibacterial agent and modified eggshell powder, and continue stirring for 20-30min; S3: Weigh sodium alginate-chitosan complex, water-based acrylic resin, and film-forming aid as needed and add them to the reactor in S2, reduce the stirring speed to 500-700 r / min, continue stirring for 20-30 min, then add the thickener and continue stirring for 10-20 min to obtain an environmentally friendly paint with antibacterial effect.

[0019] Through the above technical scheme: the modified eggshell powder is composed of calcium carbonate, and the surface properties are optimized after modification, and the dispersibility is good. It not only serves as a filling material to increase the thickness and hardness of the paint film and resist physical impact and wear, but also the surface active groups can chemically bond with the resin matrix to enhance cohesion and adhesion. At the same time, it can also form micro-roughness on the paint surface, disperse friction, and reduce wear. The sodium alginate-chitosan complex can be cross-linked with the resin matrix through electrostatic action to construct a three-dimensional network structure, enhance cohesion and elastic modulus, and the complex has both the flexibility of chitosan and the stability of sodium alginate. It can absorb energy when subjected to external force to avoid cracking and peeling. The two complement each other. The modified eggshell powder provides hardness and rigidity, and the complex enhances flexibility to achieve a balance between rigidity and flexibility. In addition, chemical bonding and cross-linking reactions work together to strengthen cohesion and adhesion, and jointly optimize the microstructure of the paint, which has the effect of greatly improving the physical and wear resistance of environmentally friendly paints.

[0020] Compared with the prior art, the present invention has the following beneficial effects: 1. In the present invention, modified eggshell powder and sodium alginate-chitosan complex are added in the process of preparing environmentally friendly paint with antibacterial effect. Since sodium alginate is a polyanionic polysaccharide, contains ionizable carboxyl groups and is negatively charged, and chitosan is rich in amino groups and is protonated and positively charged under acidic conditions, when the two are compounded, a stable structure is formed through electrostatic action. Chitosan combines with the negatively charged bacterial cell membrane by virtue of its positive charge, destroying the membrane structure and causing leakage of intracellular substances. In addition, the spatial structure of the complex hinders bacterial nutrient uptake and waste discharge, thereby significantly improving the antibacterial performance of the environmentally friendly paint.

[0021] 2. The modified eggshell powder in the present invention is modified by acetic acid to generate calcium acetate on the surface. The Ca²⁺ has a high charge density and can react with the phospholipid molecules of the bacterial cell membrane to destroy the membrane stability. At the same time, the modification promotes the release or activation of potential antibacterial components such as proteins and polypeptides, and can cooperate with the sodium alginate-chitosan complex. The sodium alginate-chitosan complex mainly interferes with the bacterial cell membrane and metabolism, and the modified eggshell powder focuses on destroying the cell membrane and releasing antibacterial components, inhibiting bacterial growth and reproduction in multiple ways and in all directions. It has a high efficiency of inhibiting common Escherichia coli, Staphylococcus aureus, etc., and further improves the antibacterial properties of environmentally friendly paints.

[0022] 3. In the present invention, water-based acrylic resin is used as the base material, and deionized water, an environmentally friendly solvent, is used to significantly reduce VOC emissions, and all raw materials meet environmental protection requirements. In addition, diatomaceous earth and bamboo charcoal powder can absorb harmful gases, further improving environmental performance. The modified eggshell powder comes from discarded eggshells, and sodium alginate and chitosan are both natural polymer materials. The entire formula is green and environmentally friendly.

[0023] 4. In the present invention, the modified eggshell powder composed of calcium carbonate can increase the thickness and hardness of the environmentally friendly paint film, resist physical impact and wear, and the surface active group can chemically bond with the resin matrix to enhance cohesion and adhesion, and the sodium alginate-chitosan complex can be cross-linked with the resin matrix through electrostatic action to construct a three-dimensional network structure, improve cohesion and elastic modulus, and the two complement each other. The modified eggshell powder provides hardness and rigidity, and the complex enhances flexibility to achieve a balance between rigidity and flexibility. In addition, chemical bonding and cross-linking reactions work together to strengthen cohesion and adhesion, and jointly optimize the paint microstructure, which has the effect of greatly improving the physical and wear resistance of environmentally friendly paints. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 The invention proposes an environmentally friendly paint with antibacterial effect and a flow chart of its preparation method. DETAILED DESCRIPTION

[0025] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0026] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the accompanying drawings.

[0027] An environmentally friendly paint with antibacterial effect comprises the following raw materials in parts by weight: 30-50 parts of water-based acrylic resin, 20-30 parts of deionized water, 8-10 parts of diatomaceous earth, 5-7 parts of bamboo charcoal powder, 3-5 parts of film-forming aid, 3-5 parts of modified eggshell powder, 2-3 parts of dispersant, 2-3 parts of thickener, 2-3 parts of sodium alginate-chitosan complex, 1-2 parts of nano silver antibacterial agent and 1-2 parts of defoamer.

[0028] The solid content of the water-based acrylic resin is (40-60)%, and the particle size of the nano-silver antibacterial agent is 20-40 nm.

[0029] The film-forming aid may be at least one of alcohol ester-12, propylene glycol phenyl ether and diethylene glycol butyl ether, and the dispersant may be at least one of polycarboxylate dispersants, alkyl naphthalene sulfonate dispersants and fatty acid polyoxyethylene ether dispersants.

[0030] The defoamer may be at least one of an organosilicon defoamer, a polyether defoamer and a mineral oil defoamer, and the thickener may be at least one of hydroxyethyl cellulose, a polyurethane thickener or a polyacrylic thickener.

[0031] Among them, the modified eggshell powder is prepared by the following method: fresh eggshells are selected as raw materials, washed with clean water, and then surface impurities and inner membranes are removed, and then placed in an oven to dry to obtain dry eggshells, and then placed in a ball mill to grind to obtain eggshell powder, and then the eggshell powder is placed in an acetic acid solution, heated to 40-60°C, and continuously stirred at 40-60r / min for 1-2h, and then filtered to obtain a crude modified eggshell powder, and then washed with ionized water to neutrality, and then placed in an oven for drying to obtain the modified eggshell powder.

[0032] In the preparation process of modified eggshell powder, the temperature of the oven is set at 100-120°C, the baking time is 2-3h, the speed of the ball mill is set at 200-300r / min, the grinding time is 2-3h, the particle size of the eggshell powder is 50-100 mesh, and the acetic acid solution is made by mixing acetic acid and water in a mass ratio of 1:19.

[0033] The sodium alginate-chitosan complex is prepared by the following method: sodium alginate solution and chitosan solution are selected, the mass ratio of the sodium alginate solution to the chitosan solution is 1: (1-2), the sodium alginate solution is heated to 30-40°C, and is continuously stirred at 100-200r / min, during which the chitosan solution is added dropwise at a dropping speed of 1-2 drops / second, and after the addition is completed, the solution is continuously stirred at 200-300r / min for 1-2h to obtain the sodium alginate-chitosan complex.

[0034] The sodium alginate solution is prepared by the following method: weigh sodium alginate agglomerates and deionized water as needed, the mass ratio of sodium alginate agglomerates to deionized water is 3:97, add deionized water and sodium alginate agglomerates into a mixer, set the speed to 100-200r / min, and continue stirring for 30-60min to obtain a sodium alginate solution.

[0035] The chitosan solution is prepared by the following method: acetic acid, chitosan and deionized water in a mass ratio of 2:3:95 are weighed as needed, acetic acid and deionized water are added to a mixer, the speed is set to 100-150 r / min, stirring is continued for 30-60 min to obtain a first solution, chitosan is then added, the speed is increased to 200-300 r / min, stirring is continued for 1-2 h to obtain a chitosan solution.

[0036] A method for preparing an environmentally friendly paint with antibacterial effect comprises the following steps: S1: Weigh deionized water as needed and add it into the reactor. Start the reactor and continue stirring at a stirring speed of 300-500r / min. Then add dispersant and defoamer in sequence and continue stirring for 20-30min. S2: Weigh diatomaceous earth and bamboo charcoal powder as needed and add them into the reactor in S1, increase the stirring speed to 800-1000r / min, continue stirring for 30-40min, then add nano-silver antibacterial agent and modified eggshell powder, and continue stirring for 20-30min; S3: Weigh sodium alginate-chitosan complex, water-based acrylic resin, and film-forming aid as needed and add them to the reactor in S2, reduce the stirring speed to 500-700 r / min, continue stirring for 20-30 min, then add the thickener and continue stirring for 10-20 min to obtain an environmentally friendly paint with antibacterial effect.

[0037] Based on the above embodiments, the inventors also conducted the following experiments:

[0038] It should be noted that the raw materials used in the following experiments are all commercially available raw materials.

[0039] Experiment 1:

[0040] Raw material preparation: 30 parts of water-based acrylic resin, 20 parts of deionized water, 8 parts of diatomaceous earth, 5 parts of bamboo charcoal powder, 3 parts of film-forming aid, 3 parts of modified eggshell powder, 2 parts of dispersant, 2 parts of thickener, 2 parts of sodium alginate-chitosan complex, 1 part of nano-silver antibacterial agent, 1 part of defoamer, the solid content of the water-based acrylic resin is 40%, the particle size of the nano-silver antibacterial agent is 20nm, the film-forming aid is alcohol ester-12, the dispersant is polycarboxylate dispersant, the defoamer is silicone defoamer, and the thickener is hydroxyethyl cellulose.

[0041] Modified eggshell powder: fresh eggshells are selected as raw materials, washed with clean water, and then surface impurities and inner membranes are removed, and then placed in an oven at a temperature set at 100°C for 2 hours to obtain dry eggshells, which are then placed in a ball mill with a speed set at 200r / min for 2 hours of grinding. The eggshell powder particle size is 50 mesh. After grinding, the eggshell powder is obtained, and then the eggshell powder is placed in an acetic acid solution, which is prepared by mixing acetic acid and water in a mass ratio of 1:19. The temperature is raised to 40°C, and the reaction is continuously stirred at 40r / min for 1 hour. After that, the crude modified eggshell powder is filtered, and then washed with ionized water until neutral, and then put into an oven for drying to obtain the modified eggshell powder; The sodium alginate-chitosan composite was prepared by the following method: sodium alginate agglomerates and deionized water were weighed as needed, the mass ratio of sodium alginate agglomerates to deionized water was 3:97, deionized water and sodium alginate agglomerates were added to a mixer, the speed was set to 100 r / min, and stirring was continued for 30 min to obtain a sodium alginate solution, acetic acid, chitosan and deionized water were weighed as needed in a mass ratio of 2:3:95, acetic acid and deionized water were added to a mixer, the speed was set to 100 r / min, The mixture was stirred for 30 min to obtain the first solution, and then chitosan was added. The rotation speed was increased to 200 r / min and the mixture was stirred for 1 h to obtain a chitosan solution. The mass ratio of the sodium alginate solution to the chitosan solution was 1:1. The sodium alginate solution was heated to 30°C and stirred at 100 r / min. The chitosan solution was added dropwise at a dropping speed of 1 drop / second. After the addition was completed, the mixture was stirred at 200 r / min for 1 h to obtain a sodium alginate-chitosan complex. Preparation of environmentally friendly paint with antibacterial effect: deionized water is weighed as needed and added to the reactor, the reactor is started, and stirring is continued at a stirring speed of 300 r / min, then dispersant and defoaming agent are added in sequence, and stirring is continued for 20 minutes, diatomaceous earth and bamboo charcoal powder are weighed as needed and added to the reactor, the stirring speed is increased to 800 r / min, and stirring is continued for 30 minutes, then nano silver antibacterial agent and modified eggshell powder are added, and stirring is continued for 20 minutes, sodium alginate-chitosan complex, water-based acrylic resin, and film-forming aid are weighed as needed and added to the reactor, the stirring speed is reduced to 500 r / min, and stirring is continued for 20 minutes, then thickener is added and stirring is continued for 10 minutes, and environmentally friendly paint with antibacterial effect is obtained.

[0042] Experiment 2:

[0043] Raw material preparation: 40 parts of water-based acrylic resin, 25 parts of deionized water, 9 parts of diatomaceous earth, 6 parts of bamboo charcoal powder, 4 parts of film-forming aid, 4 parts of modified eggshell powder, 2.5 parts of dispersant, 2.5 parts of thickener, 2.5 parts of sodium alginate-chitosan complex, 1.5 parts of nano-silver antibacterial agent, 1.5 parts of defoamer, the solid content of the water-based acrylic resin is 50%, the particle size of the nano-silver antibacterial agent is 30nm, the film-forming aid is propylene glycol phenyl ether, the dispersant is alkyl naphthalene sulfonate dispersant, the defoamer is polyether defoamer, and the thickener is polyurethane thickener.

[0044] Modified eggshell powder: fresh eggshells are selected as raw materials, washed with clean water, and then surface impurities and inner membranes are removed, and then placed in an oven at a temperature set at 150°C for 2.5 hours to obtain dry eggshells, which are then placed in a ball mill with a speed set at 250r / min for 2.5 hours of grinding. The eggshell powder particle size is 80 mesh. After grinding, the eggshell powder is obtained, and then the eggshell powder is placed in an acetic acid solution, which is prepared by mixing acetic acid and water in a mass ratio of 1:19, heated to 50°C, and stirred at 50r / min for 1.5 hours, and then filtered to obtain a crude modified eggshell powder, which is then washed with ionized water until neutral, and then placed in an oven for drying to obtain the modified eggshell powder; The sodium alginate-chitosan composite was prepared by the following method: sodium alginate agglomerates and deionized water were weighed as needed, the mass ratio of sodium alginate agglomerates to deionized water was 3:97, deionized water and sodium alginate agglomerates were added to a mixer, the speed was set to 150 r / min, and stirring was continued for 45 min to obtain a sodium alginate solution, acetic acid, chitosan and deionized water were weighed as needed in a mass ratio of 2:3:95, acetic acid and deionized water were added to the mixer, the speed was set to 125 r / min, and stirring was continued 45min, to obtain the first solution, then add chitosan, increase the speed to 250r / min, continue stirring for 1.5h, to obtain chitosan solution, the mass ratio of sodium alginate solution to chitosan solution is 1:1.5, the sodium alginate solution is heated to 35°C, and continued stirring at 150r / min, during which chitosan solution is added dropwise at a dropping speed of 1.5 drops / second, and after the addition is completed, continue stirring at 250r / min for 1.5h to obtain a sodium alginate-chitosan complex; Preparation of environmentally friendly paint with antibacterial effect: deionized water is weighed as needed and added to the reactor, the reactor is started, and stirring is continued at a stirring speed of 400 r / min, then dispersant and defoaming agent are added in sequence, and stirring is continued for 25 minutes, diatomaceous earth and bamboo charcoal powder are weighed as needed and added to the reactor, the stirring speed is increased to 900 r / min, and stirring is continued for 35 minutes, then nano silver antibacterial agent and modified eggshell powder are added, and stirring is continued for 25 minutes, sodium alginate-chitosan complex, water-based acrylic resin, and film-forming aid are weighed as needed and added to the reactor, the stirring speed is reduced to 600 r / min, and stirring is continued for 25 minutes, then thickener is added and stirring is continued for 15 minutes, and environmentally friendly paint with antibacterial effect is obtained.

[0045] Experiment 3:

[0046] Raw material preparation: 50 parts of water-based acrylic resin, 30 parts of deionized water, 10 parts of diatomaceous earth, 7 parts of bamboo charcoal powder, 5 parts of film-forming aid, 5 parts of modified eggshell powder, 3 parts of dispersant, 3 parts of thickener, 3 parts of sodium alginate-chitosan complex, 2 parts of nano-silver antibacterial agent, 2 parts of defoaming agent, the solid content of the water-based acrylic resin is 60%, the particle size of the nano-silver antibacterial agent is 40nm, the film-forming aid is diethylene glycol butyl ether, the dispersant is fatty acid polyoxyethylene ether dispersant, the defoamer is mineral oil defoamer, and the thickener is polyacrylic acid thickener.

[0047] Modified eggshell powder: fresh eggshells are selected as raw materials, washed with clean water, and then surface impurities and inner membranes are removed, and then placed in an oven at a temperature set at 120°C for 3 hours to obtain dry eggshells, which are then placed in a ball mill with a speed set at 300r / min for 3 hours of grinding. The eggshell powder particle size is 100 mesh. After grinding, the eggshell powder is obtained, and then the eggshell powder is placed in an acetic acid solution, which is prepared by mixing acetic acid and water in a mass ratio of 1:19. The temperature is raised to 60°C, and the reaction is continuously stirred at 60r / min for 2 hours. After that, the crude modified eggshell powder is filtered, and then washed with ionized water until neutral, and then put into an oven for drying to obtain the modified eggshell powder; The sodium alginate-chitosan composite was prepared by the following method: sodium alginate agglomerates and deionized water were weighed as needed, the mass ratio of sodium alginate agglomerates to deionized water was 3:97, deionized water and sodium alginate agglomerates were added to a mixer, the speed was set to 200 r / min, and stirring was continued for 60 min to obtain a sodium alginate solution, acetic acid, chitosan and deionized water were weighed as needed in a mass ratio of 2:3:95, acetic acid and deionized water were added to the mixer, and the speed was set to 150 r / min. The mixture was stirred for 60 min to obtain the first solution, and then chitosan was added. The rotation speed was increased to 300 r / min and the mixture was stirred for 2 h to obtain a chitosan solution. The mass ratio of the sodium alginate solution to the chitosan solution was 1:2. The sodium alginate solution was heated to 40°C and stirred at 200 r / min. The chitosan solution was added dropwise at a dropping speed of 2 drops / second. After the addition was completed, the mixture was stirred at 300 r / min for 2 h to obtain a sodium alginate-chitosan complex. Preparation of environmentally friendly paint with antibacterial effect: deionized water is weighed as needed and added to the reactor, the reactor is started, and stirring is continued at a stirring speed of 500 r / min, then dispersant and defoaming agent are added in sequence, and stirring is continued for 30 minutes, diatomaceous earth and bamboo charcoal powder are weighed as needed and added to the reactor, the stirring speed is increased to 1000 r / min, and stirring is continued for 40 minutes, then nano silver antibacterial agent and modified eggshell powder are added, and stirring is continued for 30 minutes, sodium alginate-chitosan complex, water-based acrylic resin, and film-forming aid are weighed as needed and added to the reactor, the stirring speed is reduced to 700 r / min, and stirring is continued for 30 minutes, then thickener is added and stirring is continued for 20 minutes, and environmentally friendly paint with antibacterial effect is obtained.

[0048] Comparative Example 1: The difference between this comparative example and Experiment 1 is that: This comparative example does not contain modified eggshell powder.

[0049] Comparative Example 2: The difference between this comparative example and Experiment 1 is that: This comparative example does not contain sodium alginate-chitosan complex.

[0050] Comparative Example 3: The difference between this comparative example and Experiment 1 is that: This comparative example does not contain modified eggshell powder and sodium alginate-chitosan complex.

[0051] Comparative Example 4: Paint was prepared using the process of Examples 1-5 of the Chinese patent application document “A composite environmentally friendly paint” (publication number: CN104893473A).

[0052] Performance test: The environmentally friendly paints with antibacterial effect prepared in Experiment 1, Experiment 2, Experiment 3, Comparative Example 1, Comparative Example 2, Comparative Example 3 and Comparative Example 4 were tested for performance, and the test data obtained are recorded in the following table:

[0053] Note: The antibacterial performance of the environmentally friendly paint is tested according to the national standard GBT21510-2008 to detect the killing rate of Escherichia coli or Staphylococcus aureus, and the national standard GBT21510-2008 stipulates 90%. The number of times of oil-resistant pen wiping is obtained by the oil-resistant pen wiping experiment. The wiping conditions are as follows: Examples 1-3 and Comparative Examples 1-7 are applied on glass, cured under 1000w ultraviolet light, and a 3cm*3cm "positive" character is written with an oil-based pen. After waiting for 5 minutes at room temperature, the character is wiped with a dust-free cloth, and the results of the number of wiping resistance are counted in turn.

[0054] It can be seen that the antibacterial performance and wear resistance of the environmentally friendly paints with antibacterial effect prepared in Comparative Examples 1, 2, 3 and 4 are lower than those in Experiments 1, 2 and 3; this shows that the antibacterial performance and wear resistance of the environmentally friendly paints can be effectively improved by adding modified eggshell powder and sodium alginate-chitosan complex in the process of preparing the environmentally friendly paints with antibacterial effect, which shows that the environmentally friendly paints with antibacterial effect and the preparation method thereof provided by the present invention have broader market prospects and are more suitable for promotion.

[0055] In the description of this specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0056] The preferred embodiments of the present invention disclosed above are only used to help illustrate the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to the specific implementation methods described. Obviously, many modifications and changes can be made according to the content of this specification. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and use the present invention well. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. An environmentally friendly paint with antibacterial effect, characterized in that: The invention comprises the following raw materials in parts by weight: 30-50 parts of water-based acrylic resin, 20-30 parts of deionized water, 8-10 parts of diatomaceous earth, 5-7 parts of bamboo charcoal powder, 3-5 parts of film-forming aid, 3-5 parts of modified eggshell powder, 2-3 parts of dispersant, 2-3 parts of thickener, 2-3 parts of sodium alginate-chitosan complex, 1-2 parts of nano silver antibacterial agent and 1-2 parts of defoaming agent.

2. The environmentally friendly paint with antibacterial effect according to claim 1, characterized in that: The solid content of the water-based acrylic resin is (40-60)%, and the particle size of the nano silver antibacterial agent is 20-40 nm.

3. The environmentally friendly paint with antibacterial effect according to claim 1, characterized in that: The film-forming aid may be at least one of alcohol ester-12, propylene glycol phenyl ether and diethylene glycol butyl ether, and the dispersant may be at least one of polycarboxylate dispersants, alkyl naphthalene sulfonate dispersants and fatty acid polyoxyethylene ether dispersants.

4. The environmentally friendly paint with antibacterial effect according to claim 1, characterized in that: The defoamer may be at least one of an organosilicon defoamer, a polyether defoamer and a mineral oil defoamer, and the thickener may be at least one of hydroxyethyl cellulose, a polyurethane thickener or a polyacrylic thickener.

5. The environmentally friendly paint with antibacterial effect according to claim 1, characterized in that: The modified eggshell powder is prepared by the following method: fresh eggshells are selected as raw materials, washed with clean water, and then surface impurities and inner membranes are removed, and then dried in an oven to obtain dry eggshells, and then ground in a ball mill to obtain eggshell powder, and then the eggshell powder is placed in an acetic acid solution, heated to 40-60°C, and continuously stirred at 40-60r / min for 1-2h, and then filtered to obtain a crude modified eggshell powder, and then washed with ionized water until neutral, and then dried in an oven to obtain the modified eggshell powder.

6. The environmentally friendly paint with antibacterial effect according to claim 5, characterized in that: During the preparation of the modified eggshell powder, the temperature of the oven is set at 100-120°C, the baking time is 2-3 hours, the speed of the ball mill is set at 200-300 r / min, the grinding time is 2-3 hours, the particle size of the eggshell powder is 50-100 mesh, and the acetic acid solution is prepared by mixing acetic acid and water in a mass ratio of 1:

19.

7. The environmentally friendly paint with antibacterial effect according to claim 1, characterized in that: The sodium alginate-chitosan complex is prepared by the following method: selecting a sodium alginate solution and a chitosan solution, wherein the mass ratio of the sodium alginate solution to the chitosan solution is 1:(1-2), heating the sodium alginate solution to 30-40°C, and continuously stirring at 100-200 r / min, during which the chitosan solution is added dropwise at a dropping speed of 1-2 drops / second, and after the addition is completed, continuously stirring at 200-300 r / min for 1-2 hours to obtain the sodium alginate-chitosan complex.

8. The environmentally friendly paint with antibacterial effect according to claim 7, characterized in that: The sodium alginate solution is prepared by the following method: sodium alginate agglomerates and deionized water are weighed as needed, the mass ratio of the sodium alginate agglomerates to the deionized water is 3:97, the deionized water and the sodium alginate agglomerates are added into a mixer, the speed is set to 100-200 r / min, and stirring is continued for 30-60 min to obtain the sodium alginate solution.

9. The environmentally friendly paint with antibacterial effect according to claim 7, characterized in that: The chitosan solution is prepared by the following method: acetic acid, chitosan and deionized water are weighed in a mass ratio of 2:3:95 as required, acetic acid and deionized water are added to a mixer, the speed is set to 100-150 r / min, stirring is continued for 30-60 min to obtain a first solution, chitosan is then added, the speed is increased to 200-300 r / min, stirring is continued for 1-2 h to obtain a chitosan solution.

10. A method for preparing an environmentally friendly paint with antibacterial effect as claimed in any one of claims 1 to 9, characterized in that: The following steps are involved: S1: Weigh deionized water as needed and add it into the reactor. Start the reactor and continue stirring at a stirring speed of 300-500r / min. Then add dispersant and defoamer in sequence and continue stirring for 20-30min. S2: Weigh diatomaceous earth and bamboo charcoal powder as needed and add them into the reactor in S1, increase the stirring speed to 800-1000r / min, continue stirring for 30-40min, then add nano-silver antibacterial agent and modified eggshell powder, and continue stirring for 20-30min; S3: Weigh sodium alginate-chitosan complex, water-based acrylic resin, and film-forming aid as needed and add them to the reactor in S2, reduce the stirring speed to 500-700 r / min, continue stirring for 20-30 min, then add the thickener and continue stirring for 10-20 min to obtain an environmentally friendly paint with antibacterial effect.

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