Dual formaldehyde-removing antibacterial coating and preparation method thereof

Abstract

The present application belongs to the technical field of building coatings, and relates to a dual formaldehyde-removing and antibacterial coating and a preparation method thereof. The formaldehyde-removing and antibacterial coating prepared by the method can effectively remove formaldehyde under the action of ultraviolet light catalyst, and at the same time, the amino group can react with the negative charge on the bacterial cell membrane to cause the integrity of the bacterial cell membrane to be destroyed, so that the permeability of the bacterial cell membrane is changed, the cell contents are leaked, and finally the cell death is caused. The polyethylene imine grafted sodium alginate is introduced into the surface of titanium dioxide, so that the high adsorption performance of the alginate on formaldehyde and the dual formaldehyde-removing and antibacterial effect are utilized, and the dispersibility of the filler in the coating matrix is improved through the chemical bond and action between the amino group carried by the polyethylene imine and the epoxy resin. Therefore, the agglomeration problem of the inorganic filler is reduced, the formaldehyde-removing and antibacterial performance of the coating is improved, and the efficient and long-lasting application of the functional coating in the natural indoor environment is realized.

Description

Technical Field

[0001] This invention belongs to the field of architectural coatings technology, and relates to a dual formaldehyde-removing and antibacterial coating and its preparation method. Background Technology

[0002] Formaldehyde (HCHO) is an important chemical raw material widely used in the manufacture of resins, polymers, adhesives, preservatives, and building materials. These products and materials can continuously release formaldehyde for months or even years during thermal and chemical decomposition. Short-term exposure to formaldehyde can cause irritation, allergies, red eyes, and liver and immune system damage, while long-term exposure can lead to serious health problems such as nasopharyngeal carcinoma, childhood leukemia, and brain cancer. Bacteria, mold, and other microorganisms easily proliferate on wall surfaces, especially in high-humidity environments. They not only affect indoor air quality but also cause health problems. Therefore, developing a coating with formaldehyde removal and antibacterial functions can not only help manage indoor air quality but also more comprehensively protect people's health.

[0003] Polyethyleneimine (PEI) is a multifunctional polymer with a highly reactive amino structure, commonly used to adsorb and decompose formaldehyde molecules in the air. Due to its rich amino groups in its molecular chain, PEI can effectively react chemically with formaldehyde, fixing it and reducing its volatilization. Furthermore, the antibacterial properties of polyethyleneimine have attracted considerable attention; it can inhibit the growth of bacteria and microorganisms, making it widely applicable in air purification and antibacterial fields. Therefore, PEI is an ideal multifunctional material suitable for improving indoor air quality and environmental protection.

[0004] The active oxygen generated by the photocatalysis of titanium dioxide can effectively decompose formaldehyde molecules adsorbed on the surface of titanium dioxide, converting them into non-toxic water and carbon dioxide, thereby purifying the air.

[0005] Alginate has a porous structure, which effectively adsorbs harmful substances in the air, including formaldehyde. This property makes alginate a natural and effective choice for air purification. Furthermore, alginate maintains its adsorption effect for a long time, is not easily saturated, and thus achieves a sustained air purification effect. Its biodegradability also gives it a unique advantage in environmental protection.

[0006] Because commercially available paints are ineffective at removing formaldehyde, prolonged ventilation is required to reduce formaldehyde levels when used indoors. Combining the three substances mentioned above would undoubtedly solve this technical problem more effectively. Therefore, this patent invention presents a dual-action formaldehyde-removing and antibacterial paint. Summary of the Invention

[0007] To address the aforementioned technical problems, the present invention aims to provide a dual formaldehyde-removing and antibacterial coating and its preparation method. The formaldehyde-removing and antibacterial coating prepared by this method effectively removes formaldehyde using ultraviolet photocatalysis. Simultaneously, through a chemical reaction between amino groups and formaldehyde, it also electrostatically interacts with the negatively charged portions of bacterial cell membranes, disrupting the integrity of the bacterial cell membranes and altering their permeability, leading to leakage of cell contents and ultimately cell death. Introducing polyethyleneimine-grafted sodium alginate onto the surface of titanium dioxide not only utilizes the high formaldehyde adsorption capacity and dual formaldehyde-removing and antibacterial effects of alginate, but also improves the dispersibility of fillers in the coating matrix through the chemical bonding between the amino groups carried by polyethyleneimine and epoxy resin. This reduces the agglomeration problem of inorganic fillers and improves the formaldehyde-removing and antibacterial performance of the coating, enabling the efficient and long-lasting application of functional coatings in natural indoor environments.

[0008] To achieve the above objectives, the present invention adopts the following technical solution.

[0009] A dual formaldehyde-removing and antibacterial coating comprises the following raw materials in parts by weight: 16-20 parts of acid-treated polyethyleneimine-grafted sodium alginate, 1-2 parts of titanium dioxide with self-encapsulated polydopamine on its surface, 100-200 parts of waterborne epoxy resin, and 40-80 parts of epoxy curing agent.

[0010] A method for preparing a dual formaldehyde-removing and antibacterial coating specifically includes the following steps:

[0011] Step 1: After reacting acidified polyethyleneimine-grafted sodium alginate with 4-dimethylaminopyridine, the mixture is filtered, washed, and dried to obtain pyrene-functionalized acidified polyethyleneimine-grafted sodium alginate.

[0012] Step 2: Place titanium dioxide in a buffer solution containing dopamine, stir, centrifuge and dry to obtain titanium dioxide with self-encapsulated polydopamine on the surface.

[0013] Step 3: Disperse the pyrene-functionalized acidified polyethyleneimine-grafted sodium alginate prepared in Step 1 into deionized water containing triethylamine, and then add it to the titanium dioxide dispersion containing self-encapsulated polydopamine on the surface prepared in Step 2 to obtain a ternary catalyst; add the ternary catalyst to a buffer solution for acidification treatment, stir, wash and dry at room temperature to obtain a ternary catalyst carrying protonated amine.

[0014] Step 4: Weigh 16-20 parts of the ternary catalyst carrying protonated amine, then weigh 50-100 parts of deionized water and 100-200 parts of waterborne epoxy resin. Stir at 500 r / min for 30 min, then sonicate for 10 min to obtain a mixed waterborne epoxy resin. Weigh 40-80 parts of epoxy curing agent and 50-100 parts of deionized water, stir magnetically at 100 r / min for 15-20 min, then mix with the mixed waterborne epoxy resin at a mass ratio of 10:7 to obtain a dual formaldehyde-removing antibacterial coating.

[0015] Further, the specific preparation method of the acidified polyethyleneimine-grafted sodium alginate in step 1 is as follows: dissolve 5-10 parts of polyethyleneimine in 50-70 parts of deionized water, and add 16-20 parts of sodium alginate to obtain a mixture; keep the mixture at 60°C and shake at 500 rpm for 8 hours in an incubator; then add 5 parts of 3% (v / v) glutaraldehyde and continue shaking at 60°C for 7 hours to obtain polyethyleneimine-grafted sodium alginate; add 4 parts of concentrated hydrochloric acid to 100 parts of ethanol / water (60 parts: 40 parts) mixture to obtain a hydrochloric acid-alcohol mixture; slowly add 4 parts of polyethyleneimine-grafted sodium alginate to the hydrochloric acid-alcohol mixture and stir vigorously overnight at room temperature; after the reaction is completed, start filtration and thoroughly wash the filter paper with the ethanol / water mixture to remove chloride ions to obtain acidified polyethyleneimine-grafted sodium alginate.

[0016] Further, the specific steps of step 1 are as follows: acidified polyethyleneimine-grafted sodium alginate and 3 parts of 1-pyrene methanol are dissolved in 30 parts of dichloromethane, stirred under N2 atmosphere, and placed in an ice bath; then 2 parts of dicyclohexylcarbodiimide and 2 parts of 4-dimethylaminopyridine are dissolved together in the above dichloromethane, stirred at room temperature for 3 hours, then the mixture is raised to room temperature and the reaction continues for 12 hours, filtered, washed, and dried to obtain pyrene-functionalized acidified polyethyleneimine-grafted sodium alginate.

[0017] Furthermore, in step 2, there are 5 parts titanium dioxide, 2 parts dopamine, and 10 parts buffer solution. The buffer solution is Tris-HCl buffer with a concentration of 1.21 g / L and a pH of 8.5.

[0018] Furthermore, in step 2, the stirring speed is 300-500 r / min, and the stirring time is 24h.

[0019] Further, the specific steps of step 3 are as follows: 16-20 parts of pyrene-functionalized acidified polyethyleneimine-grafted sodium alginate and 20-40 parts of deionized water containing 3-5 parts of triethylamine are mixed and kept under ultrasonic conditions until the pyrene-functionalized acidified polyethyleneimine-grafted sodium alginate dissolves. The resulting solution is added to an aqueous dispersion containing 1-2 parts of titanium dioxide with self-encapsulated polydopamine on its surface. Then, 2 parts of L-ascorbic acid are added to the resulting mixture, and the mixture is stirred at 80°C for 20 hours. The precipitate is collected by filtration and washed three times to obtain a ternary catalyst. The ternary catalyst is added to 3-5 parts of hydrochloric acid buffer solution (pH=5.8) for acidification treatment. After stirring at room temperature for 1 hour, the mixture is washed and dried to obtain a ternary catalyst carrying protonated amines.

[0020] Furthermore, the waterborne epoxy resin is one of DY-128-50 epoxy resin, E51 epoxy emulsion, F0716 epoxy resin, E20 epoxy emulsion, and E44 epoxy emulsion.

[0021] Furthermore, the epoxy curing agent is one of W650, H228B, Aq419, and W651.

[0022] Compared with the prior art, the beneficial effects of the present invention are as follows.

[0023] 1. This invention uses a ternary catalyst with covalent bonds of polydopamine / titanium dioxide on alginate derivatives as a filler for the coating. The chemical bonding between the amino groups carried by polyethyleneimine and the epoxy resin improves the dispersibility of the filler in the coating matrix, avoids the separation of the inorganic filler and the organic resin, and effectively improves the formaldehyde removal and antibacterial properties of the coating. The chemical bonding between the two components gives the coating excellent mechanical stability, and the cross-linked network structure between the polymers steadily improves chemical stability.

[0024] 2. This invention utilizes the photocatalytic properties of titanium dioxide to initially decompose formaldehyde in the air under light conditions. Simultaneously, it leverages the high adsorption capacity of alginate in the acidified ternary catalyst for formaldehyde and the irreversible nucleophilic addition reaction between the protonated amine of polyethyleneimine and formaldehyde to achieve secondary degradation of formaldehyde. This two-step formaldehyde removal effect enables the efficient and long-lasting application of functional coatings in natural indoor environments.

[0025] 3. In addition to having dual formaldehyde removal functionality, this invention utilizes the high-density cations of polyethyleneimine and the photothermal effect of polydopamine to destroy the cell membrane of bacteria, thereby exerting an antibacterial effect. Attached Figure Description

[0026] Figure 1 This is a diagram illustrating the formaldehyde removal mechanism of the dual formaldehyde-removing and antibacterial coating prepared according to the present invention.

[0027] Figure 2 The formaldehyde removal and carbon dioxide production of the coating prepared in Example 1 of this invention are given.

[0028] Figure 3 The formaldehyde removal stability of the coating prepared in Example 1 of this invention.

[0029] Figure 4 The number and distribution of Escherichia coli colonies in the six groups of samples.

[0030] Figure 5 The number and distribution of Staphylococcus aureus colonies in the six groups of samples are shown. Detailed Implementation

[0031] The following discloses some embodiments of the present invention. Those skilled in the art can appropriately modify the process parameters to achieve the desired results based on the content of this document. It should be particularly noted that all similar substitutions and modifications are obvious to those skilled in the art and are considered to be included in this invention. The methods and applications of the present invention have been described through preferred embodiments. Those skilled in the art can obviously make modifications or appropriate alterations and combinations to the methods and applications described herein without departing from the content, spirit, and scope of the present invention to implement and apply the technology of the present invention.

[0032] A dual formaldehyde-removing and antibacterial coating comprises the following raw materials in parts by weight: 16-20 parts of acid-treated polyethyleneimine-grafted sodium alginate, 1-2 parts of titanium dioxide with self-encapsulated polydopamine on its surface, 100-200 parts of waterborne epoxy resin, and 40-80 parts of epoxy curing agent.

[0033] A method for preparing a dual formaldehyde-removing and antibacterial coating specifically includes the following steps:

[0034] Step 1: Dissolve acidified polyethyleneimine-grafted sodium alginate and 3 parts of 1-pyrene methanol in 30 parts of dichloromethane, stir under N2 atmosphere, and then place in an ice bath; then dissolve 2 parts of dicyclohexylcarbodiimide and 2 parts of 4-dimethylaminopyridine together in the above dichloromethane, stir at room temperature for 3 hours, then raise the mixture to room temperature and continue the reaction for 12 hours, filter, wash and dry to obtain pyrene-functionalized acidified polyethyleneimine-grafted sodium alginate;

[0035] Step 2: Place 5 parts of titanium dioxide in 10 parts of Tris-HCl buffer containing 2 parts of dopamine, stir at 300-500 r / min for 24 h, then centrifuge and dry to obtain titanium dioxide with self-encapsulated polydopamine on the surface; buffer concentration: 1.21 g / L, pH=8.5;

[0036] Step 3: Mix 16-20 parts of pyrene-functionalized acidified polyethyleneimine-grafted sodium alginate and 20-40 parts of deionized water containing 3-5 parts of triethylamine, and maintain the mixture under ultrasonic conditions until the pyrene-functionalized acidified polyethyleneimine-grafted sodium alginate dissolves. Add the resulting solution to an aqueous dispersion containing 1-2 parts of titanium dioxide with self-encapsulated polydopamine on its surface. Then add 2 parts of L-ascorbic acid to the resulting mixture and stir at 80°C for 20 hours. Collect the precipitate by filtration and wash it three times to obtain a ternary catalyst. Add the ternary catalyst to 3-5 parts of hydrochloric acid buffer solution (pH=5.8) for acidification treatment. Stir at room temperature for 1 hour, then wash and dry to obtain a ternary catalyst carrying protonated amines.

[0037] Step 4: Weigh 16-20 parts of the ternary catalyst carrying protonated amine, then weigh 50-100 parts of deionized water and 100-200 parts of waterborne epoxy resin. Stir at 500 r / min for 30 min, then sonicate for 10 min to obtain a mixed waterborne epoxy resin. Weigh 40-80 parts of epoxy curing agent and 50-100 parts of deionized water, stir magnetically at 100 r / min for 15-20 min, then mix with the mixed waterborne epoxy resin at a mass ratio of 10:7 to obtain a dual formaldehyde-removing antibacterial coating.

[0038] Further, the specific preparation method of the acidified polyethyleneimine-grafted sodium alginate in step 1 is as follows: dissolve 5-10 parts of polyethyleneimine in 50-70 parts of deionized water, and add 16-20 parts of sodium alginate to obtain a mixture; keep the mixture at 60°C and shake at 500 rpm for 8 hours in an incubator; then add 5 parts of 3% (v / v) glutaraldehyde and continue shaking at 60°C for 7 hours to obtain polyethyleneimine-grafted sodium alginate; add 4 parts of concentrated hydrochloric acid to 100 parts of ethanol / water (60 parts: 40 parts) mixture to obtain a hydrochloric acid-alcohol mixture; slowly add 4 parts of polyethyleneimine-grafted sodium alginate to the hydrochloric acid-alcohol mixture and stir vigorously overnight at room temperature; after the reaction is completed, start filtration and thoroughly wash the filter paper with the ethanol / water mixture to remove chloride ions to obtain acidified polyethyleneimine-grafted sodium alginate.

[0039] Furthermore, the waterborne epoxy resin is one of DY-128-50 epoxy resin, E51 epoxy emulsion, F0716 epoxy resin, E20 epoxy emulsion, and E44 epoxy emulsion.

[0040] Furthermore, the epoxy curing agent is one of W650, H228B, Aq419, and W651.

[0041] Example 1.

[0042] A method for preparing a dual formaldehyde-removing and antibacterial coating, comprising the following steps:

[0043] Step 1: Dissolve 5 parts of polyethyleneimine in 50 parts of deionized water and add 16 parts of sodium alginate to obtain a mixture; keep the mixture at 60°C and shake at 500 rpm for 8 hours in an incubator; then add 5 parts of 3% (v / v) glutaraldehyde and continue shaking at 60°C for 7 hours to obtain polyethyleneimine-grafted sodium alginate; add 4 parts of concentrated hydrochloric acid to 100 parts of ethanol / water (60 parts: 40 parts) mixture to obtain a hydrochloric acid-alcohol mixture; slowly add 4 parts of polyethyleneimine-grafted sodium alginate to the hydrochloric acid-alcohol mixture and stir vigorously overnight at room temperature; after the reaction is complete, start filtration and thoroughly wash the filter paper with the ethanol / water mixture to remove chloride ions to obtain acidified polyethyleneimine-grafted sodium alginate.

[0044] 16 parts of acidified polyethyleneimine-grafted sodium alginate and 3 parts of 1-pyrene methanol were dissolved in 30 parts of dichloromethane and stirred under N2 atmosphere in an ice bath. Then, 2 parts of dicyclohexylcarbodiimide and 2 parts of 4-dimethylaminopyridine were dissolved together in the above dichloromethane and stirred at room temperature for 3 hours. The mixture was then raised to room temperature and reacted for another 12 hours. The mixture was filtered, washed, and dried to obtain pyrene-functionalized acidified polyethyleneimine-grafted sodium alginate.

[0045] Step 2: Place 5 parts of titanium dioxide in 10 parts of Tris-HCl buffer containing 2 parts of dopamine (buffer concentration: 1.21 g / L, pH=8.5), stir at 300-500 r / min for 24 h, centrifuge and dry to obtain titanium dioxide with self-encapsulated polydopamine on the surface.

[0046] Step 3: Mix 16 parts of pyrene-functionalized acidified polyethyleneimine-grafted sodium alginate with 20 parts of deionized water containing 3 parts of triethylamine, and maintain the mixture under ultrasonic conditions until the pyrene-functionalized acidified polyethyleneimine-grafted sodium alginate dissolves. Add the resulting solution to 1 part of an aqueous dispersion of titanium dioxide containing self-encapsulated polydopamine on its surface. Then add 2 parts of L-ascorbic acid to the resulting mixture and stir at 80 °C for 20 hours. Collect the precipitate by vacuum filtration and wash it three times to obtain a ternary catalyst. Add the ternary catalyst to 3 parts of hydrochloric acid buffer solution (pH = 5.8) for acidification treatment. Stir at room temperature for 1 hour, then wash and dry to obtain a ternary catalyst carrying protonated amines.

[0047] Step 4: Weigh 16 parts of the ternary catalyst carrying protonated amine and add it to a beaker. Then weigh 50 parts of deionized water and 100 parts of DY-128-50 epoxy resin and add them to the beaker. Stir at 500 r / min for 30 min and then sonicate for 10 min to obtain mixed DY-128-50 epoxy resin. Weigh 40 parts of W650 epoxy curing agent and 50 parts of deionized water and stir magnetically at 100 r / min for 15 min. Then mix them with the mixed DY-128-50 epoxy resin at a mass ratio of 10:7 to obtain a dual formaldehyde-removing antibacterial coating.

[0048] Example 2.

[0049] A method for preparing a dual formaldehyde-removing and antibacterial coating, comprising the following steps:

[0050] Step 1: Dissolve 5 parts of polyethyleneimine in 50 parts of deionized water and add 18 parts of sodium alginate to obtain a mixture; keep the mixture at 60°C and shake at 500 rpm for 8 hours in an incubator; then add 5 parts of 3% (v / v) glutaraldehyde and continue shaking at 60°C for 7 hours to obtain polyethyleneimine-grafted sodium alginate; add 4 parts of concentrated hydrochloric acid to 100 parts of ethanol / water (60 parts: 40 parts) mixture to obtain a hydrochloric acid-alcohol mixture; slowly add 4 parts of polyethyleneimine-grafted sodium alginate to the hydrochloric acid-alcohol mixture and stir vigorously overnight at room temperature; after the reaction is complete, start filtration and thoroughly wash the filter paper with the ethanol / water mixture to remove chloride ions to obtain acidified polyethyleneimine-grafted sodium alginate.

[0051] 16 parts of acidified polyethyleneimine-grafted sodium alginate and 3 parts of 1-pyrene methanol were dissolved in 30 parts of dichloromethane and stirred under N2 atmosphere in an ice bath. Then, 2 parts of dicyclohexylcarbodiimide and 2 parts of 4-dimethylaminopyridine were dissolved together in the above dichloromethane and stirred at room temperature for 3 hours. The mixture was then raised to room temperature and reacted for another 12 hours. The mixture was filtered, washed, and dried to obtain pyrene-functionalized acidified polyethyleneimine-grafted sodium alginate.

[0052] Step 2: Place 5 parts of titanium dioxide in 10 parts of Tris-HCl buffer containing 2 parts of dopamine (buffer concentration: 1.21 g / L, pH=8.5), stir at 300-500 r / min for 24 h, centrifuge and dry to obtain titanium dioxide with self-encapsulated polydopamine on the surface.

[0053] Step 3: Mix 16 parts of pyrene-functionalized acidified polyethyleneimine-grafted sodium alginate with 20 parts of deionized water containing 3 parts of triethylamine, and maintain the mixture under ultrasonic conditions until the pyrene-functionalized acidified polyethyleneimine-grafted sodium alginate dissolves. Add the resulting solution to 1 part of an aqueous dispersion of titanium dioxide containing self-encapsulated polydopamine on its surface. Then add 2 parts of L-ascorbic acid to the resulting mixture and stir at 80 °C for 20 hours. Collect the precipitate by vacuum filtration and wash it three times to obtain a ternary catalyst. Add the ternary catalyst to 3 parts of hydrochloric acid buffer solution (pH = 5.8) for acidification treatment. Stir at room temperature for 1 hour, then wash and dry to obtain a ternary catalyst carrying protonated amines.

[0054] Step 4: Weigh 16 parts of the ternary catalyst carrying protonated amine and add it to a beaker. Then weigh 50 parts of deionized water and 100 parts of DY-128-50 epoxy resin and add them to the beaker. Stir at 500 r / min for 30 min and then sonicate for 10 min to obtain mixed DY-128-50 epoxy resin. Weigh 40 parts of W650 epoxy curing agent and 50 parts of deionized water and stir magnetically at 100 r / min for 15 min. Then mix them with the mixed DY-128-50 epoxy resin at a mass ratio of 10:7 to obtain a dual formaldehyde-removing antibacterial coating.

[0055] Example 3.

[0056] A method for preparing a dual formaldehyde-removing and antibacterial coating includes the following steps:

[0057] Step 1: Dissolve 5 parts of polyethyleneimine in 50 parts of deionized water and add 20 parts of sodium alginate to obtain a mixture; keep the mixture at 60°C and shake at 500 rpm for 8 hours in an incubator; then add 5 parts of 3% (v / v) glutaraldehyde and continue shaking at 60°C for 7 hours to obtain polyethyleneimine-grafted sodium alginate; add 4 parts of concentrated hydrochloric acid to 100 parts of ethanol / water (60 parts: 40 parts) mixture to obtain a hydrochloric acid-alcohol mixture; slowly add 4 parts of polyethyleneimine-grafted sodium alginate to the hydrochloric acid-alcohol mixture and stir vigorously overnight at room temperature; after the reaction is complete, start filtration and thoroughly wash the filter paper with the ethanol / water mixture to remove chloride ions to obtain acidified polyethyleneimine-grafted sodium alginate.

[0058] 16 parts of acidified polyethyleneimine-grafted sodium alginate and 3 parts of 1-pyrene methanol were dissolved in 30 parts of dichloromethane and stirred under N2 atmosphere in an ice bath. Then, 2 parts of dicyclohexylcarbodiimide and 2 parts of 4-dimethylaminopyridine were dissolved together in the above dichloromethane and stirred at room temperature for 3 hours. The mixture was then raised to room temperature and reacted for another 12 hours. The mixture was filtered, washed, and dried to obtain pyrene-functionalized acidified polyethyleneimine-grafted sodium alginate.

[0059] Step 2: Place 5 parts of titanium dioxide in 10 parts of Tris-HCl buffer containing 2 parts of dopamine (buffer concentration: 1.21 g / L, pH=8.5), stir at 300-500 r / min for 24 h, centrifuge and dry to obtain titanium dioxide with self-encapsulated polydopamine on the surface.

[0060] Step 3: Mix 16 parts of pyrene-functionalized acidified polyethyleneimine-grafted sodium alginate with 20 parts of deionized water containing 3 parts of triethylamine, and maintain the mixture under ultrasonic conditions until the pyrene-functionalized acidified polyethyleneimine-grafted sodium alginate dissolves. Add the resulting solution to 1 part of an aqueous dispersion of titanium dioxide containing self-encapsulated polydopamine on its surface. Then add 2 parts of L-ascorbic acid to the resulting mixture and stir at 80 °C for 20 hours. Collect the precipitate by vacuum filtration and wash it three times to obtain a ternary catalyst. Add the ternary catalyst to 3-5 parts of hydrochloric acid buffer solution (pH = 5.8) for acidification treatment. Stir at room temperature for 1 hour, then wash and dry to obtain a ternary catalyst carrying protonated amines.

[0061] Step 4: Weigh 16 parts of the ternary catalyst carrying protonated amine and add it to a beaker. Then weigh 50 parts of deionized water and 100 parts of DY-128-50 epoxy resin and add them to the beaker. Stir at 500 r / min for 30 min and then sonicate for 10 min to obtain mixed DY-128-50 epoxy resin. Weigh 40 parts of W650 epoxy curing agent and 50 parts of deionized water and stir magnetically at 100 r / min for 15 min. Then mix them with the mixed DY-128-50 epoxy resin at a mass ratio of 10:7 to obtain a dual formaldehyde-removing antibacterial coating.

[0062] Comparative Example 1.

[0063] A method for preparing a waterborne epoxy resin coating includes the following steps:

[0064] Weigh 50 parts of deionized water and 100 parts of DY-128-50 epoxy resin and add them to a beaker. Stir at 500 r / min for 30 min and then sonicate for 10 min to obtain a mixed DY-128-50 epoxy resin. Weigh 40 parts of W650 epoxy curing agent and 50 parts of deionized water and stir magnetically at 100 r / min for 15 min. Then mix them with the mixed DY-128-50 epoxy resin at a mass ratio of 10:7 to obtain a water-based epoxy resin coating.

[0065] Comparative Example 2.

[0066] A method for preparing a water-based formaldehyde-removing and antibacterial epoxy resin coating includes the following steps:

[0067] 16 parts of titanium dioxide containing self-encapsulated polydopamine from Example 1 were weighed and added to a beaker. Then, 50 parts of deionized water and 100 parts of DY-128-50 epoxy resin were weighed and added to the beaker. The mixture was stirred at 500 r / min for 30 min and then sonicated for 10 min to obtain mixed DY-128-50 epoxy resin. 40 parts of W650 epoxy curing agent and 50 parts of deionized water were weighed and magnetically stirred at 100 r / min for 15 min. Then, the mixture was mixed with the mixed DY-128-50 epoxy resin at a mass ratio of 10:7 to obtain a water-based formaldehyde-removing and antibacterial epoxy resin coating.

[0068] Comparative Example 3.

[0069] A method for preparing a water-based formaldehyde-removing and antibacterial epoxy resin coating includes the following steps:

[0070] 16 parts of pyrene-functionalized acidified polyethyleneimine-grafted sodium alginate from Example 1 were weighed and added to a beaker. Then, 50 parts of deionized water and 100 parts of DY-128-50 epoxy resin were weighed and added to the beaker. The mixture was stirred at 500 r / min for 30 min and then sonicated for 10 min to obtain mixed DY-128-50 epoxy resin. 40 parts of W650 epoxy curing agent and 50 parts of deionized water were weighed and magnetically stirred at 100 r / min for 15 min. Then, the mixture was mixed with the mixed DY-128-50 epoxy resin at a mass ratio of 10:7 to obtain a water-based formaldehyde-removing antibacterial coating.

[0071] test:

[0072] Test 1: The formaldehyde removal performance of the coatings prepared from Examples 1, 2, and 3 and Comparative Examples 1, 2, and 3 (referred to as Group A, Group B, Group C, Group D, Group E, and Group F, respectively) was compared. Test conditions: Temperature (20±2)℃, relative humidity (50±10)%, cubic test chamber: 1m 3 The equipment included a 300W fluorescent lamp and a 15W air fan. The coating was applied to one side of the inside of the test chamber to a thickness of (2±0.02) mm. After air drying at room temperature for 7 days, the experiment was conducted by introducing a certain concentration of formaldehyde, and then measuring the formaldehyde concentration after 24 hours.

[0073] Analysis: The formaldehyde degradation rates of the six groups of samples are shown in Table 1. The formaldehyde degradation rates of the three examples are all greater than 96%, which shows that they have high formaldehyde removal efficiency. This is the result of the ternary catalyst as a functional material, where the protonated amines on its surface and the active oxygen on the surface work together to remove formaldehyde. The three comparative examples have poorer formaldehyde degradation effects compared to the examples because they lack or have only one formaldehyde removal functional filler.

[0074] Table 1. Formaldehyde concentration adsorbed by the coating.

[0075]

[0076] Test 2: Six groups of samples underwent bacterial adsorption tests against *E. coli* and *Staphylococcus aureus*. All samples were sterilized with UV light for half an hour before the experiment. Samples were placed into 25 mL of 1×10⁻⁶ solution. 5 The samples were co-cultured in CFU / mL Escherichia coli and Staphylococcus aureus at 37 °C in the dark for 3 h. After incubation, the samples were gently rinsed with sterile physiological saline to remove any unattached bacteria. The samples were then placed in new centrifuge tubes, 25 mL of physiological saline was added, and the mixture was sonicated for 3 min. 100 μL of the bacterial culture was then inoculated onto nutrient agar plates and incubated at 37 °C for 18 h. The colony count was then performed. Figure 4 , Figure 5 As shown.

[0077] CFU: Colony forming unit, refers to each colony formed on an agar plate after incubation at a certain temperature and time. It is a unit for counting the number of bacteria or fungi.

Claims

1. A dual-action formaldehyde-removing and antibacterial coating, characterized in that, The raw materials include the following parts by weight: 16-20 parts of acid-treated polyethyleneimine-grafted sodium alginate, 1-2 parts of titanium dioxide with self-encapsulated polydopamine on the surface, 100-200 parts of water-based epoxy resin, and 40-80 parts of epoxy curing agent. The preparation method of the dual formaldehyde-removing and antibacterial coating specifically includes the following steps: Step 1: Dissolve acidified polyethyleneimine-grafted sodium alginate and 3 parts of 1-pyrene methanol in 30 parts of dichloromethane, stir under N2 atmosphere, and then place in an ice bath; then dissolve 2 parts of dicyclohexylcarbodiimide and 2 parts of 4-dimethylaminopyridine together in the above dichloromethane, stir at room temperature for 3 hours, then raise the mixture to room temperature and continue the reaction for 12 hours, filter, wash and dry to obtain pyrene-functionalized acidified polyethyleneimine-grafted sodium alginate; Step 2: Place titanium dioxide in a buffer solution containing dopamine, stir, centrifuge and dry to obtain titanium dioxide with self-encapsulated polydopamine on the surface. Step 3: Disperse the pyrene-functionalized acidified polyethyleneimine-grafted sodium alginate prepared in Step 1 into deionized water containing triethylamine, and then add it to the titanium dioxide dispersion containing self-encapsulated polydopamine on the surface prepared in Step 2 to obtain a ternary catalyst; add the ternary catalyst to a buffer solution for acidification treatment, stir, wash and dry at room temperature to obtain a ternary catalyst carrying protonated amine. Step 4: Weigh 16-20 parts of the ternary catalyst carrying protonated amine, then weigh 50-100 parts of deionized water and 100-200 parts of waterborne epoxy resin. Stir at 500 r / min for 30 min, then sonicate for 10 min to obtain a mixed waterborne epoxy resin. Weigh 40-80 parts of epoxy curing agent and 50-100 parts of deionized water, stir magnetically at 100 r / min for 15-20 min, then mix with the mixed waterborne epoxy resin at a mass ratio of 10:7 to obtain a dual formaldehyde-removing antibacterial coating.

2. A method for preparing a dual formaldehyde-removing and antibacterial coating as described in claim 1, characterized in that, Specifically, the following steps are included: Step 1: Dissolve acidified polyethyleneimine-grafted sodium alginate and 3 parts of 1-pyrene methanol in 30 parts of dichloromethane, stir under N2 atmosphere, and place in an ice bath. Then, dissolve 2 parts of dicyclohexylcarbodiimide and 2 parts of 4-dimethylaminopyridine together in the above dichloromethane and stir at room temperature for 3 hours. Then, raise the mixture to room temperature and continue the reaction for 12 hours. Filter, wash, and dry to obtain pyrene-functionalized acidified polyethyleneimine-grafted sodium alginate. Step 2: Place titanium dioxide in a buffer solution containing dopamine, stir, centrifuge and dry to obtain titanium dioxide with self-encapsulated polydopamine on the surface. Step 3: Disperse the pyrene-functionalized acidified polyethyleneimine-grafted sodium alginate prepared in Step 1 into deionized water containing triethylamine, and then add it to the titanium dioxide dispersion containing self-encapsulated polydopamine on the surface prepared in Step 2 to obtain a ternary catalyst. The three-way catalyst was added to a buffer solution for acidification, and then stirred, washed, and dried at room temperature to obtain a three-way catalyst carrying protonated amines. Step 4: Weigh 16-20 parts of the ternary catalyst carrying protonated amine, then weigh 50-100 parts of deionized water and 100-200 parts of waterborne epoxy resin. Stir at 500 r / min for 30 min, then sonicate for 10 min to obtain a mixed waterborne epoxy resin. Weigh 40-80 parts of epoxy curing agent and 50-100 parts of deionized water, stir magnetically at 100 r / min for 15-20 min, then mix with the mixed waterborne epoxy resin at a mass ratio of 10:7 to obtain a dual formaldehyde-removing antibacterial coating.

3. The preparation method of the dual formaldehyde-removing and antibacterial coating according to claim 2, characterized in that, In step 1, the specific preparation method of acidified polyethyleneimine-grafted sodium alginate is as follows: 5-10 parts of polyethyleneimine are dissolved in 50-70 parts of deionized water, and 16-20 parts of sodium alginate are added to obtain a mixture; the mixture is kept at 60°C and shaken at 500 rpm for 8 hours in an incubator; then 5 parts of 3% v / v glutaraldehyde are added, and shaking is continued at 60°C for 7 hours to obtain polyethyleneimine-grafted sodium alginate; 4 parts of concentrated hydrochloric acid are added to a 100-part ethanol / water 60-part:40 mixture to obtain a hydrochloric acid-alcohol mixture; 4 parts of polyethyleneimine-grafted sodium alginate are slowly added to the hydrochloric acid-alcohol mixture, and the mixture is stirred vigorously overnight at room temperature. After the reaction is completed, filtration is started, and the filter paper is thoroughly washed with an ethanol / water mixture to remove chloride ions to obtain acidified polyethyleneimine-grafted sodium alginate.

4. The preparation method of the dual formaldehyde-removing and antibacterial coating according to claim 2, characterized in that, In step 2, 5 parts titanium dioxide and 2 parts dopamine are used; 10 parts buffer solution is used, and the buffer solution is Tris-HCl buffer solution with the following concentration: 1.21 g / L, pH=8.

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5. The preparation method of the dual formaldehyde-removing and antibacterial coating according to claim 2, characterized in that, In step 2, the stirring speed is 300-500 r / min, and the stirring time is 24h.

6. The preparation method of the dual formaldehyde-removing and antibacterial coating according to claim 2, characterized in that, The specific steps of step 3 are as follows: 16-20 parts of pyrene-functionalized acidified polyethyleneimine-grafted sodium alginate and 20-40 parts of deionized water containing 3-5 parts of triethylamine are mixed and kept under ultrasonic conditions until the pyrene-functionalized acidified polyethyleneimine-grafted sodium alginate dissolves. The resulting solution is added to an aqueous dispersion containing 1-2 parts of titanium dioxide with self-encapsulated polydopamine on the surface. Then, 2 parts of L-ascorbic acid are added to the resulting mixture and stirred at 80°C for 20 hours. The precipitate is collected by filtration and washed three times to obtain a ternary catalyst. The ternary catalyst was added to 3-5 parts of hydrochloric acid buffer solution for acidification treatment. The hydrochloric acid buffer solution had a pH of 5.

8. After stirring at room temperature for 1 hour, the catalyst was washed and dried to obtain a ternary catalyst carrying protonated amines.

7. The preparation method of the dual formaldehyde-removing and antibacterial coating according to claim 2, characterized in that, The waterborne epoxy resin is one of DY-128-50 epoxy resin, E51 epoxy emulsion, F0716 epoxy resin, E20 epoxy emulsion, and E44 epoxy emulsion.

8. The preparation method of the dual formaldehyde-removing and antibacterial coating according to claim 2, characterized in that, The epoxy curing agent is one of W650, H228B, Aq419, and W651.

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