Long-acting fluorescent antibacterial coating and preparation method thereof

Abstract

The invention discloses a long-acting fluorescent antibacterial coating and a preparation method thereof, and belongs to the technical field of chemical materials. The coating consists of polyurethane and SrAl2O4: Eu < 3 + > and Dy < 3 + > powder dispersed in the polyurethane, according to the invention, the polyurethane-strontium aluminate coating is formed on the surface of the substrate, so that the adhesive force of the coating on the surface of the substrate can be enhanced, the SrAl2O4: Eu < 3 + > and Dy < 3 + > powder can continuously release trace active oxygen free radicals in an illumination environment, and the SrAl2O4: Eu < 3 + > and Dy < 3 + > powder can emit fluorescence in the dark and continuously release the active oxygen free radicals for 2 hours, thereby realizing continuous antibacterial effect. The polyurethane-strontium aluminate coating is prepared in the mode that the polyurethane coating and the SrAl2O4: Eu < 3 + > and Dy < 3 + > powder are mixed and coated, lasting fluorescence is achieved, meanwhile, the long-acting antibacterial effect is achieved, and the existence of the antibacterial effect of the coating can be verified through the existence of fluorescence when no illumination exists; and moreover, no heavy metal ions are released, the environment-friendly effect is achieved, and the problems of bacterium attachment and pollution on the surface of a solid base material are effectively solved.

Description

Technical Field

[0001] The invention belongs to the technical field of chemical materials and specifically relates to a preparation method of a long-lasting fluorescent antibacterial coating. Background Art

[0002] Bacterial pollution mainly refers to the process in which common bacteria or bacteria existing in a specific environment release secretions that have adverse effects on the surrounding environment, causing changes in the physical and chemical properties of the environment. This process often leads to health crises and economic losses. From a health perspective, the World Health Organization announced in 2019 that about 700,000 people die directly or indirectly from infections caused by bacteria each year. It is estimated that this number will increase to 10 million by the middle of this century. From an economic perspective, it is estimated that the economic losses caused by bacterial pollution will reach 100 trillion by 2050. In response to the above problems, the development of antibacterial related technologies at home and abroad is as follows: 1. Antibiotics β-lactam antibiotics can kill bacteria by inhibiting the synthesis of bacterial cell walls, causing defects in bacterial cell walls and thus losing their support and barrier functions. Its representative drugs include penicillin, cephalosporin and their respective derivatives or ionic salts, etc. It is also one of the earliest antibacterial drugs used in the world, and its use time has exceeded 80 years. Its main advantage is that due to the relatively simple mechanism of action, the effect is relatively clear and controllable; the main body is synthesized by organisms (Penicillium), eliminating many cumbersome chemical synthesis processes. However, the disadvantages are also very obvious. In the decades since the discovery and application of antibiotics, bacterial resistance has become increasingly higher: this means that without changing the type of drug, the amount of drug required to achieve a certain antibacterial effect will become higher and higher. At present, considering the development speed of new antibiotics and the growth rate of drug resistance of conventional pathogens, the cost of using this method to fight bacteria is high and the benefits are low.

[0003] 2. Metal Nanoparticles The earliest antibacterial method is to use metal products for antibacterial purposes. Now, with the development of nanoparticle-related technologies, metal nanoparticles for antibacterial purposes, such as silver nanoparticles, are widely used in fields such as stomatology. Silver nanoparticles can slowly release silver ions in aqueous solution, and silver ions can pass through the cell wall of bacteria, enter the cell and combine or react with proteins, enzymes and other substances, causing bacteria to be damaged and inactivated. Its advantages are good antibacterial effects and a broad antibacterial spectrum; but its disadvantages are that it is dependent on the aqueous solution environment, and it takes a long time to work. In addition, compared with other methods, the cost of silver nanoparticles for antibacterial purposes is also higher.

[0004] 3. Structural sterilization By constructing nanostructures, structures with different characteristics are formed on the surface of the substrate, such as zinc oxide nanopillars, to physically kill bacteria. This antibacterial method of constructing structures has developed rapidly in recent years. Its main advantage is that it will not be affected by bacterial resistance, and there is no pollution or release; but its disadvantage is that the construction process of its antibacterial structure is relatively complicated and costly, and generally has strict requirements on the substrate, so the scope of application is relatively limited.

[0005] Although the above methods can solve the problem of bacterial contamination to a certain extent, they have limitations to varying degrees in terms of cost, action conditions and application scenarios. Summary of the invention

[0006] In view of the limitations of the above-mentioned antibacterial materials and methods, the present invention proposes a long-lasting fluorescent antibacterial coating and a preparation method thereof. The coating is formed by adhering to SrAl2O4:Eu 3+ ,Dy 3+ The active oxygen free radicals occasionally produced by the powder under light conditions kill bacteria.

[0007] The first aspect of the present invention provides a long-lasting fluorescent antibacterial coating, which comprises a polyurethane coating and SrAl2O4:Eu dispersed in the polyurethane coating. 3+ ,Dy 3+ Powder; wherein the molar ratio of Sr: Al: Eu: Dy is 1: (1.8~2.2): (0.08~0.12): (0.12~0.16).

[0008] Preferably, based on the mass of the antibacterial coating being 100%, the mass content of the polyurethane coating is 90-99%, SrAl2O4:Eu 3+ ,Dy 3+ The mass content of the powder is 1-10%, and the thickness of the antibacterial coating is 5-15 μm.

[0009] The second aspect of the present invention provides a method for preparing a long-lasting fluorescent antibacterial coating, comprising the following steps: (1) Preparation of SrAl2O4:Eu 3+ ,Dy 3+ powder; (2) Preparation of polyurethane solution: The diol is dissolved in an organic solvent, shaken to make it fully dissolved, and then the diisocyanate is added and mixed to prepare a polyurethane, and the two are shaken at room temperature to mix them evenly to obtain a polyurethane solution; (3) Preparation of long-lasting fluorescent antibacterial coating The SrAl2O4:Eu 3+ ,Dy 3+The powder is ground to a particle size of 1-10 μm, and then doped into the polyurethane solution of step (2) according to 1-10% of the total mass of the coating, ultrasonicated at room temperature for 1-5 min, and then coated on the substrate, and heated and cured to obtain a long-lasting fluorescent antibacterial coating.

[0010] Preferably, the diol is a combination of one or more of polyethylene glycol with a molecular weight of 200-2000 and polyester diol with a molecular weight of 3000-5000; the diisocyanate is a combination of one or more of 2,6-toluene diisocyanate (TDI), hexamethylene diisocyanate (MDI), and naphthalene diisocyanate; and the organic solvent is one of acetone, butyl acetate, dimethylformamide, and toluene.

[0011] Further preferably, the mass ratio of the diol to the diisocyanate is 1:(1-0.5); the mass ratio of the diol to the organic solvent is 1:(2-5).

[0012] Preparation of SrAl2O4:Eu in step (1) 3+ ,Dy 3+ The powder method, the steps are as follows: SrCO3, Al2O3, Eu2O3, Dy2O3 and boric acid were mixed and ground until the mixture was uniform and free of particles, and then loaded into a crucible. The whole was placed in a high-temperature box-type electric furnace, and a carbon block was used to create and maintain a CO gas atmosphere. SrAl2O4:Eu was obtained by heating to 1400 °C and keeping the temperature for 6 to 7 hours. 3+ ,Dy 3+ Powder; the molar ratio of SrCO3 to Al2O3 is 1: (0.9~1.1), the molar ratio of SrCO3 to Eu2O3 is 1: (0.04~0.06), the molar ratio of SrCO3 to Dy2O3 is 1: (0.06~0.08), and the molar ratio of SrCO3 to boric acid is 1: (0.05~0.08).

[0013] Beneficial effects of the present invention: According to the preparation method of the present invention, a long-lasting fluorescent antibacterial coating is constructed on a substrate by spin coating; since the polyurethane coating can be firmly bonded to most solid surfaces, the antibacterial coating can be applied to various common solid surfaces and has universal applicability. 3+ ,Dy 3+ Eu and Dy, as doped ions, produce electron transfer. This reversible reaction process can react with O2 in the air to continuously generate trace amounts of active oxygen free radicals, which in turn kill various bacteria attached to the coating, thus having a broad-spectrum antibacterial effect. At the same time, since the generated active oxygen free radicals are always maintained at a low concentration level, it is biosafe. The coating prepared by the present invention is not affected by bacterial resistance; it can exert antibacterial effect when exposed to light in the air, and has a wide range of applications; the fluorescence and antibacterial effects can continue to exist for more than 2 hours after the light is stopped, and the antibacterial effect lasts for a long time; in addition, the coating is chemically inert, not easy to physically or chemically react with other substances, no heavy metal ions are released, and it is environmentally friendly; the preparation process is relatively simple and low in cost; the chemical properties of the antibacterial body are stable and not easy to fail. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 :SrAl2O4:Eu 3+ ,Dy 3+ Powder fluorescent effect picture; Figure 2 :SrAl2O4:Eu 3+ ,Dy 3+ Powder fluorescence intensity-time variation diagram; Figure 3 : Schematic diagram of the structure of long-lasting fluorescent antibacterial coating; Figure 4 : Comparison chart of antibacterial experimental effects. DETAILED DESCRIPTION

[0016] In order to better illustrate the purpose, implementation mode and technical means of the present invention, the present invention is further described in detail below in conjunction with several specific embodiments. It should be noted that the protection scope of the present invention should not be limited to the following embodiments.

[0017] Example 1 1. SrAl2O4:Eu 3+ ,Dy 3+ Powder synthesis Accurately weigh 1.25 g SrCO3, 1.00 g Al2O3, 0.09 g Eu2O3, 0.20 g Dy2O3, and 0.10 g H3BO3 solids, grind them in a mortar to make them fully and evenly mixed, put the resulting mixture into a small crucible and open it into a large crucible with a built-in carbon block, put the whole into a high-temperature box-type electric furnace, heat it to 1400 ° C and keep it warm for 6.5 h to allow the reaction to proceed fully. After cooling, take out the solid product in the small crucible, crush it and grind it until there are no obvious particles, and then put it into a ball mill for 24 h to obtain 99% SrAl2O4:Eu with a particle size between 1 and 10 μm. 3+ ,Dy 3+ powder.

[0018] 2. Preparation of polyurethane Accurately weigh 2.00 g of polyethylene glycol with a molecular weight of 2000, add 4.00 g of butyl acetate, shake to fully dissolve it, then add 1.00 g of hexamethylene diisocyanate (MDI), and shake thoroughly to mix it evenly.

[0019] 3. Preparation of long-lasting fluorescent antibacterial coating Accurately weigh 0.03 g of prepared SrAl2O4:Eu 3+ ,Dy 3+ The powder was doped into the prepared polyurethane. After ultrasonic treatment for 3 min, the mixture was sucked with a rubber-tipped dropper and a drop of the mixture was added to a glass sheet of 2.5 cm × 2.5 cm fixed on a spin coater. The speed was set to 3000 rpm and the time was 15 s. After the spin coating was completed, the glass sheet was moved to an oven and heated and cured at 50 ° C for 10 h to obtain a long-lasting fluorescent antibacterial coating with a powder loading of 1 wt%.

[0020] Example 2 1. SrAl2O4:Eu 3+ ,Dy 3+ Powder synthesis Accurately weigh 1.20 g SrCO3, 1.00 g Al2O3, 0.10 g Eu2O3, 0.22 g Dy2O3, and 0.08 g H3BO3 solids, grind them in a mortar to make them fully and evenly mixed, put the resulting mixture into a small crucible and open it into a large crucible with a built-in carbon block, put the whole into a high-temperature box-type electric furnace, heat it to 1400 ° C and keep it warm for 6 hours to allow the reaction to proceed fully. After cooling, take out the solid product in the small crucible, crush it and grind it until there are no obvious particles, and then put it into a ball mill for 20 hours to obtain 99% SrAl2O4:Eu with a particle size between 1 and 10 μm. 3+ ,Dy 3+ powder.

[0021] 2. Preparation of polyurethane Accurately weigh 2.00 g of polyether diol with a molecular weight of 3000, add 4.00 g of acetone, shake to fully dissolve it, then add 1.00 g of naphthalene diisocyanate, shake thoroughly to mix it evenly.

[0022] 3. Preparation of long-lasting fluorescent antibacterial coating Accurately weigh 0.09 g of prepared SrAl2O4:Eu 3+ ,Dy 3+The powder was doped into the prepared polyurethane. After ultrasonic treatment for 5 min, the mixture was sucked with a rubber-tipped dropper and dropped on a glass sheet of 2.5 cm × 2.5 cm in size. The drop was allowed to stand at room temperature for 10 min to allow the drop to spread evenly over the entire surface. The glass sheet was moved to an oven and heated and cured at 60 °C for 12 h to obtain a long-lasting fluorescent antibacterial coating with a powder loading of 3 wt%.

[0023] Example 3 1. SrAl2O4:Eu 3+ ,Dy 3+ Powder synthesis Accurately weigh 1.20 g SrCO3, 1.00 g Al2O3, 0.10 g Eu2O3, 0.22 g Dy2O3, and 0.08 g H3BO3 solids, grind them in a mortar to make them fully and evenly mixed, put the resulting mixture into a small crucible and open it into a large crucible with a built-in carbon block, put the whole into a high-temperature box-type electric furnace, heat it to 1400 ° C and keep it warm for 6 hours to allow the reaction to proceed fully. After cooling, take out the solid product in the small crucible, crush it and grind it until there are no obvious particles, and then put it into a ball mill for 24 hours to obtain 99% SrAl2O4:Eu with a particle size between 1 and 10 μm. 3+ ,Dy 3+ powder.

[0024] 2. Preparation of polyurethane Accurately weigh 2.00 g of polyether diol with a molecular weight of 4000, add 5 g of toluene, shake to fully dissolve it, then add 1.00 g of 2,6-toluene diisocyanate (TDI), and shake thoroughly to mix it evenly.

[0025] 3. Preparation of long-lasting fluorescent antibacterial coating Accurately weigh 0.15 g of prepared SrAl2O4:Eu 3+ ,Dy 3+ The powder was doped into the prepared polyurethane, and after ultrasonic treatment for 5 min, the mixture was brushed on a glass sheet of 2.5 cm × 2.5 cm and left at room temperature for 10 min to make the surface flat. The glass sheet was moved to an oven and heated and cured at 60 °C for 12 h to obtain a long-lasting fluorescent antibacterial coating with a powder loading of 5 wt%.

[0026] Comparative Example In order to better demonstrate the antibacterial effect of the long-lasting fluorescent antibacterial coating, a glass sheet coated only with a polyurethane coating was designed as a comparative example, and its preparation process was as follows: Accurately weigh 2.00 g of polyether diol with a molecular weight of 4000, add 5 g of toluene, shake to fully dissolve it, then add 1.00 g of 2,6-toluene diisocyanate (TDI), shake to mix it evenly to obtain polyurethane. The polyurethane is brushed on a glass sheet of 2.5 cm×2.5 cm in size, and allowed to stand at room temperature for 10 min. The glass sheet is moved to an oven and heated at 60°C for 12 h for curing.

[0027] Antibacterial performance test The long-lasting fluorescent antibacterial coating prepared by the above-mentioned Example 1 and Example 2 was used for antibacterial experiments, and a pure glass sheet was used as a blank control group 1, and a glass sheet coated with polyurethane as described in the comparative example was used as a control group 2. The selected bacteria in the experiment were Escherichia coli (G-) and Staphylococcus aureus (G+). Since the antibacterial mode of active oxygen free radicals is free diffusion sterilization, the expected result of the experiment is that Staphylococcus aureus with a larger specific surface area is more easily killed. This test was conducted by the film pasting method, which meets the requirements of the national standard.

[0028] The test experimental steps are as follows: take the glass pieces coated with the long-lasting fluorescent antibacterial coating prepared in the above-mentioned Examples 1 and 2, and the above-mentioned blank control group 1 and control group 2, respectively, use 75% ethanol ultrasonic cleaning for 3 min, and then use ultraviolet light to disinfect for 30 minutes; drip 50 μL of 1×10 6 CFU / ml of bacterial solution, and then cover the sample with a 2 cm×2 cm PET film. Care should be taken to avoid bacterial solution seepage from the edge of the PET film, and ensure that there are no obvious bubbles between the PET film and the sample to ensure maximum contact between the bacterial solution and the coating. Culture under light for 5 h, then place each in 5 ml phosphate buffer (pH=7.4) for 3 min of ultrasound, take 100 μL of the liquid after ultrasound from each group and spread it on solid LB medium, place it in a 37 ℃ incubator for 16 h, and observe the growth of colonies in each group and count them.

[0029] For the glass sheets coated with polyurethane, considering the adhesion of polyurethane to bacteria, the bacteria will be damaged to a certain extent during the ultrasound process. Therefore, it is necessary to separately compare the antibacterial effects of the blank control group 1 and the control group 2. Detailed antibacterial effect data analysis is shown in the attached figure. Figure 4 As shown, it can be seen that no matter compared with the pure glass sheet group or the polyurethane-coated glass sheet group, the long-lasting fluorescent antibacterial coating group showed excellent antibacterial effect, and the killing rate against Staphylococcus aureus was higher than that against Escherichia coli, which was in line with the expected results of the experiment.

[0030] In summary, the long-lasting fluorescent antibacterial coating prepared by the present application has good antibacterial properties and can be applied to a variety of solid surfaces. The above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention shall be included in the protection scope of the present invention.

Claims

1. A long-lasting fluorescent antibacterial coating, characterized in that: The coating comprises a polyurethane coating and SrAl2O4:Eu dispersed in the polyurethane coating. 3+ ,Dy 3+ Powder; wherein the molar ratio of Sr: Al: Eu: Dy is 1: (1.8~2.2): (0.08~0.12): (0.12~0.16).

2. The long-lasting fluorescent antibacterial coating according to claim 1, characterized in that: Taking the mass of the antibacterial coating as 100%, the mass content of the polyurethane coating is 90-99%, SrAl2O4:Eu 3+ ,Dy 3+ The mass content of the powder is 1-10%, and the thickness of the antibacterial coating is 5-15 μm.

3. A method for preparing the long-lasting fluorescent antibacterial coating according to claim 1, characterized in that: The method comprises the following steps: (1) Preparation of SrAl2O4:Eu 3+ ,Dy 3+ Powder, wherein the molar ratio of Sr: Al: Eu: Dy is 1: (1.8-2.2): (0.08-0.12): (0.12-0.16); (2) Preparation of polyurethane solution: The diol is dissolved in an organic solvent, shaken to make it fully dissolved, and then the diisocyanate is added and mixed to prepare a polyurethane, and the two are shaken at room temperature to mix them evenly to obtain a polyurethane solution; (3) Preparation of long-lasting fluorescent antibacterial coating The SrAl2O4:Eu 3+ ,Dy 3+ The powder is ground to a particle size of 1-10 μm, and then doped into the polyurethane solution of step (2) according to 1-10% of the total mass of the coating, ultrasonicated at room temperature for 1-5 min, and then coated on the substrate, and heated and cured to obtain a long-lasting fluorescent antibacterial coating.

4. The method for preparing the long-lasting fluorescent antibacterial coating according to claim 3, characterized in that: The diol is a combination of one or more of polyethylene glycol with a molecular weight of 200-2000 and polyester diol with a molecular weight of 3000-5000; the diisocyanate is a combination of one or more of 2,6-toluene diisocyanate (TDI), hexamethylene diisocyanate (MDI), and naphthalene diisocyanate.

5. The method for preparing the long-lasting fluorescent antibacterial coating according to claim 3, characterized in that: The organic solvent is one of acetone, butyl acetate, dimethylformamide and toluene.

6. The method for preparing the long-lasting fluorescent antibacterial coating according to claim 4, characterized in that: The mass ratio of the diol to the diisocyanate is 1:(1-0.5); the mass ratio of the diol to the organic solvent is 1:(2-5).

7. The method for preparing the long-lasting fluorescent antibacterial coating according to claim 3, characterized in that: Preparation of SrAl2O4:Eu in step (1) 3+ ,Dy 3+ The powder method, the steps are as follows: SrCO3, Al2O3, Eu2O3, Dy2O3 and boric acid were mixed and ground until the mixture was uniform and free of particles, then loaded into a crucible and placed in a high-temperature box-type electric furnace. Carbon blocks were used to create and maintain a CO gas atmosphere. SrAl2O4:Eu was obtained by heating to 1400 °C and keeping the temperature for 6 to 7 h. 3+ ,Dy 3+ Powder; the molar ratio of SrCO3 to Al2O3 is 1: (0.9~1.1), the molar ratio of SrCO3 to Eu2O3 is 1: (0.04~0.06), the molar ratio of SrCO3 to Dy2O3 is 1: (0.06~0.08), and the molar ratio of SrCO3 to boric acid is 1: (0.05~0.08).

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