Dual formaldehyde-removing antibacterial coating and preparation method thereof

Abstract

The invention belongs to the technical field of building coatings, and relates to a dual formaldehyde-removing antibacterial coating and a preparation method thereof. According to the formaldehyde-removing antibacterial coating prepared by the method, on the basis that formaldehyde is effectively removed by the ultraviolet light catalyst, the amino group can chemically react with formaldehyde and can also generate electrostatic interaction with a negative charge part on a bacterial cell membrane at the same time, so that the integrity of the bacterial cell membrane is damaged, and the permeability of the bacterial cell membrane is changed; cell contents are leaked, and finally cell death is caused; polyethyleneimine grafted sodium alginate is introduced into the surface of titanium dioxide, so that not only are the high formaldehyde adsorption performance and double formaldehyde removal and antibacterial effects of alginate utilized, but also the dispersity of filler in a coating matrix is improved through the chemical bonding effect of amino carried by polyethyleneimine and epoxy resin; therefore, the problem of inorganic filler agglomeration is reduced, and the formaldehyde-removing and antibacterial properties of the coating are improved; the efficient and lasting application of the functional coating in a natural indoor environment is realized.

Description

Technical Field

[0001] The invention belongs to the technical field of building coatings and relates to a double formaldehyde-removing antibacterial coating and a preparation method thereof. Background Art

[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 will continue to release formaldehyde for months or even years during the process of thermal and chemical decomposition. Short-term exposure to formaldehyde can cause irritation, allergies, red eyes, and liver and immune damage, while long-term exposure may cause serious health problems such as nasopharyngeal cancer, childhood leukemia and brain cancer. Microorganisms such as bacteria and mold can easily breed on the surface of walls, especially in environments with high humidity. They not only affect indoor air quality, but also cause health problems. Therefore, developing a coating with formaldehyde removal and antibacterial functions will not only help indoor air quality management, but also protect people's health more comprehensively.

[0003] Polyethyleneimine (PEI) is a multifunctional polymer with a highly active amino structure, which is often used to adsorb and decompose formaldehyde molecules in the air. Due to the rich amino groups in its molecular chain, PEI can effectively react chemically with formaldehyde, fix it and reduce volatility. In addition, the antibacterial properties of polyethyleneimine have also attracted much attention. It can inhibit the growth of bacteria and microorganisms, making it widely used in the fields of air purification and antibacterial. Therefore, PEI is an ideal multifunctional material for improving indoor air quality and environmental protection.

[0004] The active oxygen produced by the photocatalytic action of titanium dioxide can effectively decompose the 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 that can effectively adsorb harmful substances in the air, including formaldehyde. This property makes alginate a natural and effective choice for air purification. At the same time, alginate can maintain the adsorption effect for a long time and is not easy to saturate, thus achieving a long-lasting air purification effect. Its biodegradability also gives it a unique advantage in terms of environmental protection.

[0006] Since the formaldehyde removal effect of commercial coatings is poor, long-term ventilation is required to reduce the formaldehyde content when used indoors. If the above three substances can be used in combination, this technical problem can definitely be better solved. Therefore, this patent invents a dual formaldehyde removal antibacterial coating. Summary of the invention

[0007] In view of the above-mentioned technical problems, the purpose of the present invention is to provide a dual formaldehyde removal antibacterial coating and a preparation method thereof. The formaldehyde removal antibacterial coating prepared by the method can effectively remove formaldehyde by ultraviolet photocatalysis, and can also electrostatically interact with the negatively charged part of the bacterial cell membrane while reacting chemically with formaldehyde through amino groups, resulting in the destruction of the integrity of the bacterial cell membrane, thereby causing the permeability of the bacterial cell membrane to change, resulting in leakage of cell contents, and ultimately causing cell death; polyethyleneimine is grafted onto sodium alginate and introduced onto the titanium dioxide surface, which not only utilizes the high adsorption performance of alginate for formaldehyde and the dual formaldehyde removal and antibacterial effects, but also improves the dispersibility of the filler in the coating matrix through the chemical bonds and effects of the amino groups carried by polyethyleneimine and the epoxy resin; thereby reducing the agglomeration problem of inorganic fillers and improving the formaldehyde removal and antibacterial performance of the coating; and realizing 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 solutions.

[0009] A double formaldehyde-removing antibacterial coating comprises the following raw materials in parts by mass: 16-20 parts of acidified polyethyleneimine-grafted sodium alginate, 1-2 parts of titanium dioxide with self-assembled encapsulated polydopamine on the surface, 100-200 parts of water-based epoxy resin, and 40-80 parts of epoxy curing agent.

[0010] A method for preparing a double formaldehyde-removing antibacterial coating specifically comprises the following steps: Step 1, reacting the acidified polyethyleneimine grafted sodium alginate with 4-dimethylaminopyridine, filtering, washing and drying to obtain the pyrene-functionalized acidified polyethyleneimine grafted sodium alginate; Step 2, placing titanium dioxide in a buffer solution containing dopamine, stirring and centrifuging to obtain titanium dioxide with self-assembled encapsulated polydopamine on the surface; Step 3, dispersing the pyrene-functionalized acidified polyethyleneimine-grafted sodium alginate prepared in step 1 in deionized water containing triethylamine, and then adding the dispersion of titanium dioxide containing self-assembled encapsulated polydopamine on the surface prepared in step 2 to obtain a ternary catalyst; adding the ternary catalyst to a buffer solution for acidification, stirring, washing, and drying at room temperature to obtain a ternary catalyst carrying protonated amine; Step 4, weigh 16-20 parts of a ternary catalyst carrying a protonated amine, then weigh 50-100 parts of deionized water and 100-200 parts of a water-based epoxy resin, stir at a speed of 500 r / min for 30 minutes, and ultrasonicate for 10 minutes to obtain a mixed water-based epoxy resin; weigh 40-80 parts of an epoxy curing agent and 50-100 parts of deionized water, magnetically stir at a speed of 100 r / min for 15-20 minutes, and then mix with the mixed water-based epoxy resin in a mass ratio of 10:7 to obtain a double formaldehyde-removing antibacterial coating.

[0011] Furthermore, the specific preparation method of the acidified polyethyleneimine grafted sodium alginate in step 1 is: dissolving 5-10 parts of polyethyleneimine in 50-70 parts of deionized water, and adding 16-20 parts of sodium alginate to obtain a mixture; keeping the mixture at 60°C and shaking it in an incubator at 500 rpm for 8 hours; then adding 5 parts of 3% (v / v) glutaraldehyde, and continuing to shake at 60°C for 7 hours to obtain polyethyleneimine grafted sodium alginate; adding 4 parts of concentrated hydrochloric acid to 100 parts of ethanol / water (60 parts:40 parts) mixed solution to obtain a hydrochloric acid-alcohol mixture; slowly adding 4 parts of polyethyleneimine grafted sodium alginate to the hydrochloric acid-alcohol mixture, and vigorously stirring at room temperature overnight, starting filtering after the reaction is completed, and thoroughly washing the filter paper with the ethanol / water mixture to remove chloride ions, to obtain acidified polyethyleneimine grafted sodium alginate.

[0012] Furthermore, the specific steps of step 1 are: dissolving acidified polyethyleneimine grafted sodium alginate and 3 parts of 1-pyrene methanol in 30 parts of dichloromethane, stirring under N2 atmosphere, and ice bathing; then dissolving 2 parts of dicyclohexylcarbodiimide and 2 parts of 4-dimethylaminopyridine in the above dichloromethane, and stirring at room temperature for 3 hours, then warming the mixture to room temperature, continuing the reaction for 12 hours, filtering, washing, and drying to obtain pyrene-functionalized acidified polyethyleneimine grafted sodium alginate.

[0013] Furthermore, in step 2, 5 parts of titanium dioxide, 2 parts of dopamine, and 10 parts of buffer solution, the buffer solution is Tris-HCl buffer solution, the buffer solution concentration is: 1.21 g / L, PH=8.5.

[0014] Furthermore, in step 2, the stirring speed is 300-500 r / min, and the stirring time is 24h.

[0015] Furthermore, the specific steps of step 3 are: mixing 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 keeping under ultrasonic conditions until the pyrene-functionalized acidified polyethyleneimine-grafted sodium alginate is dissolved, adding the resulting solution to an aqueous dispersion containing 1-2 parts of titanium dioxide with self-assembled encapsulated polydopamine on the surface, and then adding 2 parts of L-ascorbic acid to the resulting mixture, stirring at 80°C for 20 hours, collecting the precipitate by suction filtration and washing three times to obtain a ternary catalyst; adding the ternary catalyst to 3-5 parts of hydrochloric acid buffer solution (pH=5.8) for acidification, stirring at room temperature for 1 hour, washing and drying to obtain a ternary catalyst carrying protonated amine.

[0016] Furthermore, the water-based epoxy resin is one of DY-128-50 epoxy resin, E51 epoxy emulsion, F0716 epoxy resin, E20 epoxy emulsion, and E44 epoxy emulsion.

[0017] Furthermore, the epoxy curing agent is one of W650, H228B, Aq419, and W651.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows.

[0019] 1. The present invention adopts the covalent bond of polydopamine / titanium dioxide on alginate derivative and a ternary catalyst as the filler of the coating. The chemical bond and action of the amino group carried by polyethyleneimine and the epoxy resin improve the dispersibility of the filler in the coating matrix, avoid the two-phase separation of the inorganic filler and the organic resin, and effectively improve the formaldehyde removal and antibacterial performance of the coating. The chemical bonding between the two makes the coating have excellent mechanical stability, and the cross-linked network structure between the polymers steadily improves the chemical stability.

[0020] 2. The present invention utilizes the photocatalytic properties of titanium dioxide to preliminarily decompose formaldehyde in the air under light conditions. At the same time, the high adsorption performance of alginate in the acidified ternary catalyst for formaldehyde and the irreversible nucleophilic addition reaction between the proton amine of polyethyleneimine and formaldehyde are utilized to achieve secondary degradation of formaldehyde and a two-step formaldehyde removal functional effect, thereby realizing the efficient and long-lasting application of functional coatings in natural indoor environments.

[0021] 3. In addition to having dual formaldehyde removal functionality, the present 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. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a diagram of the formaldehyde removal mechanism of the double formaldehyde removal antibacterial coating prepared by the present invention.

[0023] Figure 2 The formaldehyde removal and carbon dioxide production of the coating prepared in Example 1 of the present invention.

[0024] Figure 3 This is the formaldehyde removal stability of the coating prepared in Example 1 of the present invention.

[0025] Figure 4 Shown are the number and distribution of Escherichia coli colonies in six groups of samples.

[0026] Figure 5 Shown are the colony counts and distribution of Staphylococcus aureus in six groups of samples. DETAILED DESCRIPTION

[0027] Some embodiments of the present invention are disclosed below, and those skilled in the art can appropriately improve the process parameters according to the content of this article. It is particularly important to point out that all similar substitutions and modifications are obvious to those skilled in the art, and they are all considered to be included in the present invention. The methods and applications of the present invention have been described through preferred embodiments, and relevant personnel can obviously modify or appropriately change and combine 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.

[0028] A double formaldehyde-removing antibacterial coating comprises the following raw materials in parts by mass: 16-20 parts of acidified polyethyleneimine-grafted sodium alginate, 1-2 parts of titanium dioxide with self-assembled encapsulated polydopamine on the surface, 100-200 parts of water-based epoxy resin, and 40-80 parts of epoxy curing agent.

[0029] A method for preparing a double formaldehyde-removing antibacterial coating specifically comprises the following steps: Step 1, dissolving the acidified polyethyleneimine grafted sodium alginate and 3 parts of 1-pyrene methanol in 30 parts of dichloromethane, stirring under N2 atmosphere, and ice bathing; then dissolving 2 parts of dicyclohexylcarbodiimide and 2 parts of 4-dimethylaminopyridine in the above dichloromethane, and stirring at room temperature for 3 hours, then warming the mixture to room temperature, continuing the reaction for 12 hours, filtering, washing, and drying to obtain the pyrene functionalized acidified polyethyleneimine grafted sodium alginate; Step 2, placing 5 parts of titanium dioxide in 10 parts of Tris-HCl buffer containing 2 parts of dopamine, rotating at a speed of 300-500 r / min, stirring for 24 hours and then centrifuging and drying to obtain titanium dioxide with self-assembled encapsulated polydopamine on the surface; buffer concentration: 1.21 g / L, pH = 8.5; Step 3, 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 is dissolved, and the resulting solution is added to an aqueous dispersion of 1-2 parts of titanium dioxide containing self-assembled encapsulated polydopamine on the surface, and then 2 parts of L-ascorbic acid are added to the resulting mixture, and stirred at 80°C for 20 hours, and the precipitate is collected by suction filtration and washed three times to obtain a three-way catalyst; the three-way catalyst is added to 3-5 parts of hydrochloric acid buffer solution (pH=5.8) for acidification, stirred at room temperature for 1 hour, and then washed and dried to obtain a three-way catalyst carrying protonated amine; Step 4, weigh 16-20 parts of a ternary catalyst carrying a protonated amine, then weigh 50-100 parts of deionized water and 100-200 parts of a water-based epoxy resin, stir at a speed of 500 r / min for 30 minutes, and ultrasonicate for 10 minutes to obtain a mixed water-based epoxy resin; weigh 40-80 parts of an epoxy curing agent and 50-100 parts of deionized water, magnetically stir at a speed of 100 r / min for 15-20 minutes, and then mix with the mixed water-based epoxy resin in a mass ratio of 10:7 to obtain a double formaldehyde-removing antibacterial coating.

[0030] Furthermore, the specific preparation method of the acidified polyethyleneimine grafted sodium alginate in step 1 is: dissolving 5-10 parts of polyethyleneimine in 50-70 parts of deionized water, and adding 16-20 parts of sodium alginate to obtain a mixture; keeping the mixture at 60°C and shaking it in an incubator at 500 rpm for 8 hours; then adding 5 parts of 3% (v / v) glutaraldehyde, and continuing to shake at 60°C for 7 hours to obtain polyethyleneimine grafted sodium alginate; adding 4 parts of concentrated hydrochloric acid to 100 parts of ethanol / water (60 parts:40 parts) mixed solution to obtain a hydrochloric acid-alcohol mixture; slowly adding 4 parts of polyethyleneimine grafted sodium alginate to the hydrochloric acid-alcohol mixture, and vigorously stirring at room temperature overnight, starting filtering after the reaction is completed, and thoroughly washing the filter paper with the ethanol / water mixture to remove chloride ions, to obtain acidified polyethyleneimine grafted sodium alginate.

[0031] Furthermore, the water-based epoxy resin is one of DY-128-50 epoxy resin, E51 epoxy emulsion, F0716 epoxy resin, E20 epoxy emulsion, and E44 epoxy emulsion.

[0032] Furthermore, the epoxy curing agent is one of W650, H228B, Aq419, and W651.

[0033] Example 1.

[0034] A preparation method of a double formaldehyde-removing antibacterial coating, comprising the following specific steps: Step 1, dissolving 5 parts of polyethyleneimine in 50 parts of deionized water, and adding 16 parts of sodium alginate to obtain a mixture; keeping the mixture at 60°C, and shaking it at 500 rpm in an incubator for 8 hours; then adding 5 parts of 3% (v / v) glutaraldehyde, and continuing to shake at 60°C for 7 hours to obtain polyethyleneimine-grafted sodium alginate; adding 4 parts of concentrated hydrochloric acid to 100 parts of ethanol / water (60 parts:40 parts) mixed solution to obtain a hydrochloric acid-alcohol mixture; slowly adding 4 parts of polyethyleneimine-grafted sodium alginate to the hydrochloric acid-alcohol mixture, and vigorously stirring at room temperature overnight, starting filtering after the reaction is completed, and thoroughly washing the filter paper with the ethanol / water mixture to remove chloride ions, to obtain acidified polyethyleneimine-grafted sodium alginate.

[0035] 16 parts of acidified polyethyleneimine grafted sodium alginate and 3 parts of 1-pyrene methanol were dissolved in 30 parts of dichloromethane, stirred under N2 atmosphere, and ice-bathed; then 2 parts of dicyclohexylcarbodiimide and 2 parts of 4-dimethylaminopyridine were dissolved in the above dichloromethane together and stirred at room temperature for 3 hours, then the mixture was warmed to room temperature and the reaction was continued for 12 hours, filtered, washed and dried to obtain pyrene-functionalized acidified polyethyleneimine grafted sodium alginate.

[0036] Step 2: Place 5 parts of titanium dioxide in 10 parts of Tris-HCl buffer (buffer concentration: 1.21 g / L, PH=8.5) containing 2 parts of dopamine, stir at 300-500 r / min for 24 hours, and centrifuge and dry to obtain titanium dioxide with self-assembled encapsulated polydopamine on the surface.

[0037] Step 3, 16 parts of pyrene-functionalized acidified polyethyleneimine-grafted sodium alginate and 20 parts of deionized water containing 3 parts of triethylamine are mixed, and kept under ultrasonic conditions until the pyrene-functionalized acidified polyethyleneimine-grafted sodium alginate is dissolved, and the resulting solution is added to 1 part of an aqueous dispersion of titanium dioxide containing self-assembled encapsulated polydopamine on the surface, and 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 suction filtration and washed three times to obtain a ternary catalyst; the ternary catalyst is added to 3 parts of hydrochloric acid buffer solution (pH = 5.8) for acidification, stirred at room temperature for 1 hour, washed and dried to obtain a ternary catalyst carrying protonated amine.

[0038] Step 4, weigh 16 parts of a ternary catalyst carrying a protonated amine and add them 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 a speed of 500 r / min for 30 minutes, and ultrasonicate for 10 minutes to obtain a mixed DY-128-50 epoxy resin; weigh 40 parts of W650 epoxy curing agent and 50 parts of deionized water, magnetically stir at a speed of 100 r / min for 15 minutes, and then mix with the mixed DY-128-50 epoxy resin in a mass ratio of 10:7 to obtain a double formaldehyde-removing antibacterial coating.

[0039] Example 2.

[0040] A preparation method of a double formaldehyde-removing antibacterial coating, comprising the following specific steps: Step 1, dissolving 5 parts of polyethyleneimine in 50 parts of deionized water, and adding 18 parts of sodium alginate to obtain a mixture; keeping the mixture at 60°C, and shaking it at 500 rpm in an incubator for 8 hours; then adding 5 parts of 3% (v / v) glutaraldehyde, and continuing to shake at 60°C for 7 hours to obtain polyethyleneimine-grafted sodium alginate; adding 4 parts of concentrated hydrochloric acid to 100 parts of ethanol / water (60 parts:40 parts) mixed solution to obtain a hydrochloric acid-alcohol mixture; slowly adding 4 parts of polyethyleneimine-grafted sodium alginate to the hydrochloric acid-alcohol mixture, and vigorously stirring at room temperature overnight, starting filtering after the reaction is completed, and thoroughly washing the filter paper with the ethanol / water mixture to remove chloride ions, to obtain acidified polyethyleneimine-grafted sodium alginate.

[0041] 16 parts of acidified polyethyleneimine grafted sodium alginate and 3 parts of 1-pyrene methanol were dissolved in 30 parts of dichloromethane, stirred under N2 atmosphere, and ice-bathed; then 2 parts of dicyclohexylcarbodiimide and 2 parts of 4-dimethylaminopyridine were dissolved in the above dichloromethane together and stirred at room temperature for 3 hours, then the mixture was warmed to room temperature and the reaction was continued for 12 hours, filtered, washed and dried to obtain pyrene-functionalized acidified polyethyleneimine grafted sodium alginate.

[0042] Step 2: Place 5 parts of titanium dioxide in 10 parts of Tris-HCl buffer (buffer concentration: 1.21 g / L, PH=8.5) containing 2 parts of dopamine, stir at 300-500 r / min for 24 hours, and centrifuge and dry to obtain titanium dioxide with self-assembled encapsulated polydopamine on the surface.

[0043] Step 3, 16 parts of pyrene-functionalized acidified polyethyleneimine-grafted sodium alginate and 20 parts of deionized water containing 3 parts of triethylamine are mixed, and kept under ultrasonic conditions until the pyrene-functionalized acidified polyethyleneimine-grafted sodium alginate is dissolved, and the resulting solution is added to 1 part of an aqueous dispersion of titanium dioxide containing self-assembled encapsulated polydopamine on the surface, and 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 suction filtration and washed three times to obtain a ternary catalyst; the ternary catalyst is added to 3 parts of hydrochloric acid buffer solution (pH = 5.8) for acidification, stirred at room temperature for 1 hour, washed and dried to obtain a ternary catalyst carrying protonated amine.

[0044] Step 4, weigh 16 parts of a ternary catalyst carrying a protonated amine and add them 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 a speed of 500 r / min for 30 minutes, and ultrasonicate for 10 minutes to obtain a mixed DY-128-50 epoxy resin; weigh 40 parts of W650 epoxy curing agent and 50 parts of deionized water, magnetically stir at a speed of 100 r / min for 15 minutes, and then mix with the mixed DY-128-50 epoxy resin in a mass ratio of 10:7 to obtain a double formaldehyde-removing antibacterial coating.

[0045] Example 3.

[0046] A method for preparing a double formaldehyde-removing antibacterial coating comprises the following steps: Step 1, dissolving 5 parts of polyethyleneimine in 50 parts of deionized water, and adding 20 parts of sodium alginate to obtain a mixture; keeping the mixture at 60°C, and shaking it at 500 rpm in an incubator for 8 hours; then adding 5 parts of 3% (v / v) glutaraldehyde, and continuing to shake at 60°C for 7 hours to obtain polyethyleneimine-grafted sodium alginate; adding 4 parts of concentrated hydrochloric acid to 100 parts of ethanol / water (60 parts:40 parts) mixed solution to obtain a hydrochloric acid-alcohol mixture; slowly adding 4 parts of polyethyleneimine-grafted sodium alginate to the hydrochloric acid-alcohol mixture, and vigorously stirring at room temperature overnight, starting filtering after the reaction is completed, and thoroughly washing the filter paper with the ethanol / water mixture to remove chloride ions, to obtain acidified polyethyleneimine-grafted sodium alginate.

[0047] 16 parts of acidified polyethyleneimine grafted sodium alginate and 3 parts of 1-pyrene methanol were dissolved in 30 parts of dichloromethane, stirred under N2 atmosphere, and ice-bathed; then 2 parts of dicyclohexylcarbodiimide and 2 parts of 4-dimethylaminopyridine were dissolved in the above dichloromethane together and stirred at room temperature for 3 hours, then the mixture was warmed to room temperature and the reaction was continued for 12 hours, filtered, washed and dried to obtain pyrene-functionalized acidified polyethyleneimine grafted sodium alginate.

[0048] Step 2: Place 5 parts of titanium dioxide in 10 parts of Tris-HCl buffer (buffer concentration: 1.21 g / L, PH=8.5) containing 2 parts of dopamine, stir at 300-500 r / min for 24 hours, and centrifuge and dry to obtain titanium dioxide with self-assembled encapsulated polydopamine on the surface.

[0049] Step 3, 16 parts of pyrene-functionalized acidified polyethyleneimine-grafted sodium alginate and 20 parts of deionized water containing 3 parts of triethylamine are mixed, and kept under ultrasonic conditions until the pyrene-functionalized acidified polyethyleneimine-grafted sodium alginate is dissolved, and the resulting solution is added to 1 part of an aqueous dispersion of titanium dioxide containing self-assembled encapsulated polydopamine on the surface, and 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 suction 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, stirred at room temperature for 1 hour, washed and dried to obtain a ternary catalyst carrying protonated amine.

[0050] Step 4, weigh 16 parts of a ternary catalyst carrying a protonated amine and add them 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 a speed of 500 r / min for 30 minutes, and ultrasonicate for 10 minutes to obtain a mixed DY-128-50 epoxy resin; weigh 40 parts of W650 epoxy curing agent and 50 parts of deionized water, magnetically stir at a speed of 100 r / min for 15 minutes, and then mix with the mixed DY-128-50 epoxy resin in a mass ratio of 10:7 to obtain a double formaldehyde-removing antibacterial coating.

[0051] Comparative example 1.

[0052] A method for preparing a water-based epoxy resin coating comprises the following steps: Weigh 50 parts of deionized water and 100 parts of DY-128-50 epoxy resin into a beaker, stir at 500 r / min for 30 minutes, and ultrasonicate for 10 minutes to obtain a mixed DY-128-50 epoxy resin; weigh 40 parts of W650 epoxy curing agent and 50 parts of deionized water, magnetically stir at 100 r / min for 15 minutes, and then mix with the mixed DY-128-50 epoxy resin in a mass ratio of 10:7 to obtain a water-based epoxy resin coating.

[0053] Comparative example 2.

[0054] A method for preparing a water-based formaldehyde-removing antibacterial epoxy resin coating comprises the following steps: Weigh 16 parts of titanium dioxide containing self-assembled encapsulated polydopamine on the surface of Example 1 and add them 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 a speed of 500 r / min for 30 minutes, and ultrasonicate for 10 minutes to obtain a mixed DY-128-50 epoxy resin; weigh 40 parts of W650 epoxy curing agent and 50 parts of deionized water, magnetically stir at a speed of 100 r / min for 15 minutes, and then mix with the mixed DY-128-50 epoxy resin in a mass ratio of 10:7 to obtain a water-based formaldehyde-removing antibacterial epoxy resin coating.

[0055] Comparative example 3.

[0056] A method for preparing a water-based formaldehyde-removing antibacterial epoxy resin coating comprises the following steps: Weigh 16 parts of pyrene-functionalized acidified polyethyleneimine-grafted sodium alginate of Example 1 and add them into a beaker, then weigh 50 parts of deionized water and 100 parts of DY-128-50 epoxy resin and add them into a beaker, stir at 500 r / min for 30 min, and ultrasonicate 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, magnetically stir at 100 r / min for 15 min, and then mix with the mixed DY-128-50 epoxy resin in a mass ratio of 10:7 to obtain a water-based formaldehyde-removing antibacterial coating.

[0057] test: Test 1: The formaldehyde removal performance of the formaldehyde removal coatings prepared from the coatings of Examples 1, 2, 3 and Comparative Examples 1, 2, 3 (respectively referred to as Group A, Group B, Group C, Group D, Group E, and Group F) was compared. Test conditions: temperature (20±2)°C, relative humidity (50±10)%, cube test chamber: 1m 3 , 300W fluorescent lamp, 15W air fan. The coating was applied on one side of the test box, with a coating thickness of (2±0.02) mm. After natural drying for 7 days at room temperature, the experiment was carried out. The experimental process was to introduce a certain concentration of formaldehyde, and then detect the formaldehyde concentration after 24 hours.

[0058] Analysis: The formaldehyde degradation rates of the six groups of samples are shown in Table 1. The degradation rates of formaldehyde in the three groups of examples are all greater than 96%, which have efficient formaldehyde removal performance. This is the result of the three-way catalyst as a functional material, and the protonated amines on its surface and the active oxygen acting together on formaldehyde. The three groups of comparative examples have poor formaldehyde degradation effects relative to the examples due to the lack or single formaldehyde removal functional filler.

[0059] Table 1 Formaldehyde concentration adsorbed by coatings.

[0060] Test 2: Six groups of samples were tested for bacterial adsorption of Escherichia coli and Staphylococcus aureus: All samples were sterilized by UV for half an hour before the experiment. The samples were placed in 25 mL of 1×10 5 CFU / mL of Escherichia coli and Staphylococcus aureus were co-cultured at 37 °C in the dark for 3 h. After the culture was completed, the sample was gently rinsed with sterile saline to remove the unapplied bacteria. The sample was then placed in a new centrifuge tube, added with 25 mL of saline for ultrasonic treatment for 3 min, and 100 μL of the bacterial solution was inoculated on the nutrient agar plate. After constant temperature culture at 37 °C for 18 h, the number of colonies was counted; Figure 4 , Figure 5 shown.

[0061] CFU: Colony forming unit, refers to each colony formed on the agar plate after cultivation at a certain temperature and time. It is the unit for calculating the number of bacteria or molds.

Claims

1. A double formaldehyde-removing antibacterial coating, characterized in that: The invention comprises the following raw materials in parts by weight: 16-20 parts of acidified polyethyleneimine grafted sodium alginate, 1-2 parts of titanium dioxide with self-assembled encapsulated polydopamine on the surface, 100-200 parts of waterborne epoxy resin, and 40-80 parts of epoxy curing agent.

2. A method for preparing a double formaldehyde-removing antibacterial coating, characterized in that: The specific steps include: Step 1, reacting the acidified polyethyleneimine grafted sodium alginate with 4-dimethylaminopyridine, filtering, washing and drying to obtain the pyrene-functionalized acidified polyethyleneimine grafted sodium alginate; Step 2, placing titanium dioxide in a buffer solution containing dopamine, stirring and centrifuging to obtain titanium dioxide with self-assembled encapsulated polydopamine on the surface; Step 3, dispersing the pyrene-functionalized acidified polyethyleneimine-grafted sodium alginate prepared in step 1 into deionized water containing triethylamine, and then adding the dispersion to the titanium dioxide containing self-assembled encapsulated polydopamine on the surface prepared in step 2 to obtain a three-way catalyst; The ternary catalyst is added into a buffer solution for acidification treatment, stirred, washed and dried at room temperature to obtain a ternary catalyst carrying a protonated amine; Step 4, weigh 16-20 parts of a ternary catalyst carrying a protonated amine, then weigh 50-100 parts of deionized water and 100-200 parts of a water-based epoxy resin, stir at a speed of 500 r / min for 30 minutes, and ultrasonicate for 10 minutes to obtain a mixed water-based epoxy resin; weigh 40-80 parts of an epoxy curing agent and 50-100 parts of deionized water, magnetically stir at a speed of 100 r / min for 15-20 minutes, and then mix with the mixed water-based epoxy resin in a mass ratio of 10:7 to obtain a double formaldehyde-removing antibacterial coating.

3. The preparation method of the double formaldehyde removal antibacterial coating according to claim 2, characterized in that: In the step 1, the specific preparation method of the acidified polyethyleneimine grafted sodium alginate is as follows: dissolving 5-10 parts of polyethyleneimine in 50-70 parts of deionized water, and adding 16-20 parts of sodium alginate to obtain a mixture; keeping the mixture at 60°C and shaking it in an incubator at 500 rpm for 8 hours; then adding 5 parts of 3% (v / v) glutaraldehyde, and continuing to shake at 60°C for 7 hours to obtain polyethyleneimine grafted sodium alginate; adding 4 parts of concentrated hydrochloric acid to 100 parts of ethanol / water (60 parts:40 parts) mixed solution to obtain a hydrochloric acid-alcohol mixture; slowly adding 4 parts of polyethyleneimine grafted sodium alginate to the hydrochloric acid-alcohol mixture, and vigorously stirring at room temperature overnight, starting filtering after the reaction is completed, and thoroughly washing the filter paper with the ethanol / water mixture to remove chloride ions, to obtain acidified polyethyleneimine grafted sodium alginate.

4. The preparation method of the double formaldehyde removal antibacterial coating according to claim 2, characterized in that: The specific steps of step 1 are: dissolving acidified polyethyleneimine grafted sodium alginate and 3 parts of 1-pyrene methanol in 30 parts of dichloromethane, stirring under N2 atmosphere, and ice bathing; then dissolving 2 parts of dicyclohexylcarbodiimide and 2 parts of 4-dimethylaminopyridine in the above dichloromethane, and stirring at room temperature for 3 hours, then warming the mixture to room temperature, continuing the reaction for 12 hours, filtering, washing, and drying to obtain pyrene-functionalized acidified polyethyleneimine grafted sodium alginate.

5. The preparation method of the double formaldehyde removal antibacterial coating according to claim 2, characterized in that: In step 2, 5 parts of titanium dioxide, 2 parts of dopamine, and 10 parts of buffer, wherein the buffer is Tris-HCl buffer, and the buffer concentration is: 1.21g / L, PH=8.

5.

6. The method for preparing the double formaldehyde-removing antibacterial coating according to claim 2, characterized in that: In the step 2, the stirring speed is 300-500 r / min, and the stirring time is 24 hours.

7. The method for preparing the double formaldehyde-removing antibacterial coating according to claim 2, characterized in that: The specific steps of step 3 are: mixing 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 keeping under ultrasonic conditions until the pyrene-functionalized acidified polyethyleneimine-grafted sodium alginate is dissolved, adding the obtained solution to an aqueous dispersion containing 1-2 parts of titanium dioxide with self-assembled encapsulated polydopamine on the surface, and then adding 2 parts of L-ascorbic acid to the obtained mixture, stirring at 80° C. for 20 hours, collecting the precipitate by suction filtration and washing 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, stirred at room temperature for 1 hour, washed and dried to obtain the ternary catalyst carrying protonated amine.

8. The method for preparing the double formaldehyde-removing antibacterial coating according to claim 2, characterized in that: The water-based epoxy resin is one of DY-128-50 epoxy resin, E51 epoxy emulsion, F0716 epoxy resin, E20 epoxy emulsion, and E44 epoxy emulsion.

9. The method for preparing the double formaldehyde-removing 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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