An environmentally friendly coating containing negative oxygen ions and its preparation method

Abstract

This invention discloses an environmentally friendly coating containing negative oxygen ions and its preparation method, belonging to the technical field of negative oxygen ion coatings. Nano-cerium oxide is obtained by co-precipitating and calcining a ligand and a cerium source; plant straw powder is impregnated with an activator, swollen, dried, and carbonized to obtain an activated carbon carrier; the activated carbon carrier, nano-cerium oxide, nano-tourmaline powder, dispersant, and deionized water are mixed, and a sodium silicate aqueous solution is added, followed by extrusion granulation and heat preservation treatment to obtain a negative oxygen ion agent; the negative oxygen ion agent is grafted with KH570 to obtain a modified negative oxygen ion agent; difunctional polyurethane acrylate, active monomer, active diluent, modified negative oxygen ion agent, wetting and dispersing agent, defoamer, leveling agent, antioxidant, and photoinitiator are mixed and stirred evenly in the dark to obtain an environmentally friendly coating containing negative oxygen ions; this invention improves upon the problems of low release efficiency, poor durability, easy agglomeration and sedimentation of inorganic powders, and poor compatibility with coating resins in existing negative oxygen ion coatings.

Description

Technical Field

[0001] This invention belongs to the field of negative oxygen ion coating technology, specifically relating to an environmentally friendly coating containing negative oxygen ions and its preparation method. Background Technology

[0002] With increasing demands for healthy living environments and green building materials, environmentally friendly coatings that sustainably release negative oxygen ions have become an important development direction for the coating industry. Negative oxygen ions can efficiently settle particulate matter, decompose harmful gases, and improve air quality, thus offering broad application prospects in interior walls, rail transportation, and home decoration coatings. Currently, negative oxygen ion coatings mainly rely on the addition of tourmaline mineral powders to achieve their function. To enhance catalytic and synergistic release effects, the industry often introduces nano-cerium oxide for compounding. However, existing technologies generally suffer from the following significant drawbacks: most existing negative oxygen ion functional materials simply involve the direct mechanical blending of tourmaline powder and nano-cerium oxide without interface design and structural composite processes. This results in uneven dispersion, easy agglomeration, weak interfacial bonding, low negative oxygen ion release efficiency, and poor durability, making it impossible to achieve stable and long-lasting release. Furthermore, both tourmaline and cerium oxide are inorganic powders with high surface polarity, leading to poor compatibility with organic systems such as UV-cured resins, making it impossible to achieve a balance between high loading capacity and high performance.

[0003] In summary, the existing technology of preparing negative ion agents by blending tourmaline powder with cerium oxide has significant limitations and cannot meet the requirements of high-end environmentally friendly functional coatings. Therefore, there is an urgent need in this field for a long-lasting, stable, high-efficiency, resin-compatible, environmentally safe negative ion coating and its preparation method. Summary of the Invention

[0004] The purpose of this invention is to provide an environmentally friendly coating containing negative oxygen ions and its preparation method, which can improve the problems of low release efficiency, poor durability, easy agglomeration and sedimentation of inorganic powders and poor compatibility with coating resins in existing negative oxygen ion coatings.

[0005] The objective of this invention can be achieved through the following technical solutions: A method for preparing an environmentally friendly coating containing negative oxygen ions includes the following steps: S1. After co-precipitation of the ligand and cerium source, nano-cerium oxide is obtained by calcination. S2. After the plant straw powder is impregnated with the activator and swollen, it is dried and then carbonized and activated under an inert atmosphere to obtain an activated carbon carrier. S3. Take the activated carbon carrier, nano-cerium oxide, nano-tourmaline powder, dispersant and deionized water, mix them, add sodium silicate aqueous solution, extrude granulation, and heat preservation treatment to obtain negative oxygen ion agent; S4. Take the negative oxygen ion agent and perform KH570 graft modification treatment to obtain a modified negative oxygen ion agent. S5. Take difunctional polyurethane acrylate, reactive monomer, reactive diluent, modified negative oxygen ion agent, wetting and dispersing agent, defoamer, leveling agent, antioxidant and photoinitiator, mix them in the dark and stir evenly to obtain an environmentally friendly coating containing negative oxygen ions.

[0006] This invention utilizes a step-by-step preparation process with multiple interconnected steps, combining various materials such as nano-cerium oxide, straw activated carbon, tourmaline powder, inorganic binder, and silane modifier to significantly enhance the release capacity of negative oxygen ions through multi-mechanism synergy. Cerium oxide prepared by coordination calcination with 1,3,5-benzenetricarboxylic acid has fine grains and a lattice rich in oxygen vacancies, exhibiting excellent air catalytic ionization activity and serving as the core catalytic center for generating negative oxygen ions. Tourmaline powder possesses piezoelectric and thermoelectric effects, spontaneously generating a micro-electric field that breaks down air water and oxygen molecules, assisting in the ionization of active ions. The porous structure of the activated carbon carrier can continuously adsorb and store environmental moisture, providing a continuous supply of reaction raw materials for the ionization reaction of cerium oxide and tourmaline. The three form a closed-loop synergistic system of electric field excitation-catalytic decomposition-raw material replenishment, significantly improving ion generation efficiency compared to single negative ion functional powders. Activated carbon porous framework, as a carrier matrix, can uniformly anchor nano-cerium oxide and ultrafine tourmaline powder in the pores and on the surface, avoiding the aggregation and stacking of nanoparticles and allowing more active sites to be exposed to air. In the process, sodium silicate aqueous solution acts as an inorganic binder, binding the three types of powders after dispersion into regular particles, fixing the relative positions of the powders, and preventing the functional components from shifting or falling off during mixing, granulation, and coating stirring. This not only solves the common problem of easy agglomeration of nanomaterials, but also stabilizes the overall structure of the functional system and effectively reduces the ion release decay rate. Activated carbon itself has a rigid framework support, providing basic mechanical strength for the negative ion agent; sodium silicate forms an inorganic cementitious network after curing, which interweaves and encapsulates various functional powders, further enhancing the particles' resistance to compression and breakage; high-strength negative oxygen ion filler is evenly dispersed inside the coating, which can fill and reinforce the polyurethane acrylate paint film. Under the synergistic effect of the system, the coating film has high hardness; at the same time, the particle structure is not easily damaged and loses its effectiveness, avoiding performance degradation caused by the shedding of functional fillers, and simultaneously improving the actual service life of the coating. KH570 silane coupling agent is used to graft and modify the molding negative oxygen ion agent to form a transitional linking layer of inorganic powder-silane intermediate-organic resin. The inorganic end of the silane bonds to the hydroxyl groups on the surface of cerium oxide, activated carbon, and tourmaline, firmly binding the inorganic functional particles; the organic acrylate end of the silane can undergo cross-linking reaction with the subsequent polyurethane acrylate resin and active monomers. This modification step connects the previous inorganic powder preparation process with the subsequent organic coating formulation process, eliminating the interfacial repulsion between inorganic fillers and organic matrix. The fillers are evenly dispersed in the paint without agglomeration, which not only fully retains the negative ion release function, but also ensures the quality of the coating film after curing, achieving a dual balance between negative oxygen ion release function and paint film adhesion performance.

[0007] As a preferred embodiment of the present invention, in step S1, the ligand is 1,3,5-benzenetricarboxylic acid; the concentration of cerium ions in the cerium source is 0.4-0.7 mol / L; and the calcination refers to heating from room temperature to 300-400℃ at a rate of 3-5℃ / min and holding at that temperature for 1.5-2.5 hours.

[0008] As a preferred embodiment of the present invention, in step S2, the carbonization activation refers to heating to 500-600℃ at a rate of 5-10℃ / min and holding for 1.5-2.5h in a nitrogen atmosphere; the activator is a zinc chloride aqueous solution, and the ratio of plant straw powder to zinc chloride aqueous solution is 1g:4-5mL; the concentration of the zinc chloride aqueous solution is 3-5mol / L.

[0009] As a preferred embodiment of the present invention, in step S3, the mass ratio of the activated carbon carrier, nano-cerium oxide, nano-tourmaline powder, dispersant, deionized water, and sodium silicate aqueous solution is 50-60:5-8:25-30:0.4-0.6:20-28:4-6; the mass fraction of the sodium silicate aqueous solution is 30%, and the modulus is 2.4; the heat preservation treatment refers to heat preservation at 80℃ for 1.5-2.5h, followed by heating to 180-220℃ and heat preservation for 2-3h; the dispersant is sodium polyacrylate.

[0010] As a preferred embodiment of the present invention, in step S4, the mass ratio of the negative oxygen ion agent to KH570 is 4-6:1.2-1.4.

[0011] As a preferred embodiment of the present invention, in step S5, the mass ratio of the difunctional polyurethane acrylate, reactive monomer, reactive diluent, modified negative oxygen ion agent, photoinitiator, leveling agent, antioxidant, defoamer and wetting and dispersing agent is 40-50:10-15:8-12:3-8:1.0-1.5:0.5-0.8:0.2-0.4:0.3-0.5:0.5-0.8.

[0012] Another objective of this invention is to provide an environmentally friendly coating containing negative oxygen ions.

[0013] As a preferred embodiment of the present invention, the leveling agent is BYK-333, the antioxidant is antioxidant 1010, the defoamer is BYK-019, the wetting and dispersing agent is BYK-190 dispersant, the active monomer is trimethylolpropane triacrylate, and the active diluent is 1,6-hexanediol diacrylate.

[0014] The beneficial effects of this invention are: This invention enhances the release performance of negative oxygen ions through multi-dimensional synergistic design: 1,3,5-phenyltricarboxylic acid is used as a co-precipitant with a cerium source, combined with a specific rate of heating and heat preservation calcination process, which can precisely control the microstructure of nano-cerium oxide, making its grains finer and its specific surface area larger, thereby improving the intrinsic activity of catalytic ionization of air to generate negative oxygen ions. The prepared plant straw-based activated carbon carrier has a rich porous structure, which can not only serve as a dispersion carrier for functional components, avoiding the agglomeration of nano-cerium oxide and nano-tourmaline, but also enrich water vapor molecules in the air, providing sufficient reactants for the ionization reaction, and forming a synergistic effect with the functional powder; the piezoelectric effect of nano-tourmaline powder and the catalytic effect of nano-cerium oxide are superimposed, further enhancing the air ionization efficiency; the synergy of these three factors improves the steady-state negative oxygen ion release concentration and long-term release stability of the coating. This invention achieves simultaneous improvement in functional and mechanical properties through interface modification and formulation optimization: KH570 is used to graft-modify the negative ion agent, allowing its organic ends to crosslink with the double bonds of the polyurethane acrylate resin, while its inorganic ends combine with the hydroxyl groups on the surface of the functional powder, effectively improving the interfacial compatibility between the inorganic powder and the organic resin matrix and avoiding coating defects caused by powder agglomeration; sodium silicate aqueous solution, as an inorganic binder, forms a stable gel phase after heat preservation treatment, enhancing both the structural stability of the negative ion agent particles and the interfacial bonding force between the composite powder and the resin system; simultaneously, by optimizing the ratio of difunctional polyurethane acrylate, reactive monomers, and reactive diluents, and combining with additives, the coating exhibits excellent pencil hardness and adhesion properties. Detailed Implementation

[0015] To further illustrate the technical means and effects of the present invention in achieving its intended purpose, the following detailed description of the specific implementation methods, structures, features, and effects of the present invention, in conjunction with embodiments, is provided below.

[0016] Example 1

[0017] 1,3,5-Benzotricarboxylic acid was dissolved in anhydrous ethanol. A cerium nitrate aqueous solution was added under reflux heating at 60°C with stirring. The mixture was stirred for 3 hours, centrifuged, and the solid phase was collected, washed, dried, and calcined to obtain nano-cerium oxide. The mass ratio of 1,3,5-Benzotricarboxylic acid, anhydrous ethanol, and cerium nitrate aqueous solution was 3:80:90. The concentration of cerium ions in the cerium nitrate aqueous solution was 0.4 mol / L. The calcination refers to heating from room temperature to 300°C at a rate of 3°C / min and holding at that temperature for 2.5 hours. Corn stalks were washed, dried, crushed, and passed through a 30-mesh sieve to obtain stalk powder. The stalk powder was then immersed in a zinc chloride aqueous solution, stirred for 30 minutes, allowed to stand for 8 hours, dried at 100°C to constant weight, carbonized and activated, washed with 1 mol / L hydrochloric acid to remove ash, and washed with water until neutral to obtain an activated carbon carrier. The carbonization and activation involved heating to 500°C at a rate of 5°C / min and holding for 1.5 hours in a nitrogen atmosphere. The ratio of stalk powder to zinc chloride aqueous solution was 1 g: 4 mL, and the concentration of the zinc chloride aqueous solution was 3 mol / L. The activated carbon carrier, nano-cerium oxide, and nano-tourmaline powder were added to a high-speed mixer and dry-mixed for 10 minutes. Sodium polyacrylate and deionized water were added and stirred for another 15 minutes. A sodium silicate aqueous solution was added and stirred for 8 minutes. The mixture was then extruded and granulated under an extrusion pressure of 2 MPa and a die orifice diameter of 0.5 mm. The mixture was then kept at 80°C for 1.5 hours and then heated to 180°C and kept at 180°C for 3 hours to obtain a negative oxygen ion agent. The mass ratio of the activated carbon carrier, nano-cerium oxide, nano-tourmaline powder, sodium polyacrylate, deionized water, and sodium silicate aqueous solution was 50:5:25:0.4:20:4. The sodium silicate aqueous solution had a mass fraction of 30% and a modulus of 2.4. The dried and dehydrated negative oxygen ion agent was added to anhydrous ethanol and ultrasonically stirred for 30 min. 0.1 mol / L hydrochloric acid solution was slowly added dropwise to adjust the pH to 4. KH570 was added, and the mixture was refluxed at 60°C with stirring for 3 h. After centrifugation, the solid phase was collected, washed, dried, and ground to obtain the modified negative oxygen ion agent. The mass ratio of the negative oxygen ion agent, anhydrous ethanol, and KH570 was 4:20:1.2. A difunctional polyurethane acrylate XH-120J (Guangdong Xinhui Chemical Co., Ltd., hereinafter the same), trimethylolpropane triacrylate, 1,6-hexanediol diacrylate, modified negative oxygen ion agent, wetting and dispersing agent, and defoamer were added to a reaction vessel and stirred at 400 r / min for 1 h. Then, a leveling agent, antioxidant, and photoinitiator 1173 were added, and the mixture was stirred at 500 r / min in the dark for 2 h to obtain an environmentally friendly coating containing negative oxygen ions. The difunctional polyurethane acrylate... The mass ratio of XH-120J, trimethylolpropane triacrylate, 1,6-hexanediol diacrylate, modified negative oxygen ion agent, photoinitiator 1173, leveling agent, antioxidant, defoamer, and wetting and dispersing agent is 40:10:8:3:1.0:0.5:0.2:0.3:0.5; the leveling agent is BYK-333, the antioxidant is antioxidant 1010, the defoamer is BYK-019, and the wetting and dispersing agent is BYK-190 dispersant.

[0018] Example 2

[0019] 1,3,5-Benzotricarboxylic acid was dissolved in anhydrous ethanol. A cerium nitrate aqueous solution was added under reflux heating at 60°C with stirring. The mixture was stirred for 3.5 hours, centrifuged, and the solid phase was collected, washed, dried, and calcined to obtain nano-cerium oxide. The mass ratio of 1,3,5-Benzotricarboxylic acid, anhydrous ethanol, and cerium nitrate aqueous solution was 3.5:85:100. The concentration of cerium ions in the cerium nitrate aqueous solution was 0.55 mol / L. The calcination referred to heating from room temperature to 350°C at a rate of 4°C / min and holding at that temperature for 2.0 hours. Corn stalks were washed, dried, crushed, and passed through a 35-mesh sieve to obtain stalk powder. The stalk powder was then immersed in a zinc chloride aqueous solution, stirred for 35 minutes, allowed to stand for 10 hours, dried at 105°C to constant weight, carbonized and activated, washed with 1 mol / L hydrochloric acid to remove ash, and washed with water until neutral to obtain an activated carbon carrier. The carbonization and activation involved heating to 550°C at a rate of 8°C / min and holding for 2.0 hours in a nitrogen atmosphere. The ratio of stalk powder to zinc chloride aqueous solution was 1 g: 4.5 mL, and the concentration of the zinc chloride aqueous solution was 4 mol / L. The activated carbon carrier, nano-cerium oxide, and nano-tourmaline powder were added to a high-speed mixer and dry-mixed for 12 minutes. Sodium polyacrylate and deionized water were added and stirring continued for 20 minutes. A sodium silicate aqueous solution was added and stirred for 10 minutes. The mixture was then extruded and granulated under an extrusion pressure of 4 MPa and a die aperture of 1.5 mm. The mixture was kept at 80°C for 2.0 h and then heated to 200°C and kept at 2.5 h to obtain a negative oxygen ion agent. The mass ratio of the activated carbon carrier, nano-cerium oxide, nano-tourmaline powder, sodium polyacrylate, deionized water, and sodium silicate aqueous solution was 55:7:28:0.5:24:5. The sodium silicate aqueous solution had a mass fraction of 30% and a modulus of 2.4. The dried and dehydrated negative oxygen ion agent was added to anhydrous ethanol and ultrasonically stirred for 35 min. 0.1 mol / L hydrochloric acid solution was slowly added dropwise to adjust the pH to 4.5. KH570 was added, and the mixture was refluxed at 60℃ with stirring for 4 h. After centrifugation, the solid phase was collected, washed, dried, and ground to obtain the modified negative oxygen ion agent. The mass ratio of the negative oxygen ion agent, anhydrous ethanol, and KH570 was 5:25:1.3. A difunctional polyurethane acrylate XH-120J, trimethylolpropane triacrylate, 1,6-hexanediol diacrylate, modified negative ion agent, wetting and dispersing agent, and defoamer were added to a reaction vessel and stirred at 500 rpm for 1.5 h. Then, a leveling agent, antioxidant, and photoinitiator 1173 were added, and the mixture was stirred at 600 rpm in the dark for 2.5 h to obtain an environmentally friendly coating containing negative ions. The difunctional polyurethane acrylate XH-120J... J. The mass ratio of trimethylolpropane triacrylate, 1,6-hexanediol diacrylate, modified negative ion agent, photoinitiator 1173, leveling agent, antioxidant, defoamer, and wetting and dispersing agent is 45:12:10:5:1.3:0.7:0.3:0.4:0.6; the leveling agent is BYK-333, the antioxidant is antioxidant 1010, the defoamer is BYK-019, and the wetting and dispersing agent is BYK-190 dispersant.

[0020] Example 3

[0021] 1,3,5-Benzotricarboxylic acid was dissolved in anhydrous ethanol. A cerium nitrate aqueous solution was added under reflux heating at 60°C with stirring. The mixture was stirred for 4 hours, centrifuged, and the solid phase was collected, washed, dried, and calcined to obtain nano-cerium oxide. The mass ratio of 1,3,5-Benzotricarboxylic acid, anhydrous ethanol, and cerium nitrate aqueous solution was 4:90:110. The concentration of cerium ions in the cerium nitrate aqueous solution was 0.7 mol / L. The calcination referred to heating from room temperature to 400°C at a rate of 5°C / min and holding at that temperature for 1.5 hours. Corn stalks were washed, dried, crushed, and passed through a 40-mesh sieve to obtain stalk powder. The stalk powder was then immersed in a zinc chloride aqueous solution, stirred for 40 minutes, allowed to stand for 12 hours, dried at 110°C to constant weight, carbonized and activated, washed with 1 mol / L hydrochloric acid to remove ash, and washed with water until neutral to obtain an activated carbon carrier. The carbonization and activation involved heating to 600°C at a rate of 10°C / min and holding for 2.5 hours in a nitrogen atmosphere. The ratio of stalk powder to zinc chloride aqueous solution was 1 g: 5 mL, and the concentration of the zinc chloride aqueous solution was 5 mol / L. The activated carbon carrier, nano-cerium oxide, and nano-tourmaline powder were added to a high-speed mixer and dry-mixed for 15 minutes. Sodium polyacrylate and deionized water were added and stirring continued for 25 minutes. A sodium silicate aqueous solution was added and stirred for 12 minutes. The mixture was then extruded and granulated under an extrusion pressure of 5 MPa and a die aperture of 2.0 mm. The mixture was kept at 80°C for 2.5 hours and then heated to 220°C and kept at 2 hours to obtain a negative oxygen ion agent. The mass ratio of the activated carbon carrier, nano-cerium oxide, nano-tourmaline powder, sodium polyacrylate, deionized water, and sodium silicate aqueous solution was 60:8:30:0.6:28:6. The sodium silicate aqueous solution had a mass fraction of 30% and a modulus of 2.4. The dried and dehydrated negative oxygen ion agent was added to anhydrous ethanol and ultrasonically stirred for 40 min. 0.1 mol / L hydrochloric acid solution was slowly added dropwise to adjust the pH to 5. KH570 was added, and the mixture was refluxed at 60℃ with stirring for 5 h. After centrifugation, the solid phase was collected, washed, dried, and ground to obtain the modified negative oxygen ion agent. The mass ratio of the negative oxygen ion agent, anhydrous ethanol, and KH570 was 6:30:1.4. A difunctional polyurethane acrylate XH-120J, trimethylolpropane triacrylate, 1,6-hexanediol diacrylate, modified negative ion agent, wetting and dispersing agent, and defoamer were added to a reaction vessel and stirred at 600 rpm for 2 hours. Then, a leveling agent, antioxidant, and photoinitiator 1173 were added, and the mixture was stirred at 700 rpm in the dark for 3 hours to obtain an environmentally friendly coating containing negative ions. The difunctional polyurethane acrylate XH-120J, ... The mass ratio of trimethylolpropane triacrylate, 1,6-hexanediol diacrylate, modified negative ion agent, photoinitiator 1173, leveling agent, antioxidant, defoamer, and wetting and dispersing agent is 50:15:12:8:1.5:0.8:0.4:0.5:0.8; the leveling agent is BYK-333, the antioxidant is antioxidant 1010, the defoamer is BYK-019, and the wetting and dispersing agent is BYK-190 dispersant.

[0022] Comparative Example 1 The difference from Example 2 is that the nano-cerium oxide does not use 1,3,5-benzenetricarboxylic acid for coordination, but is directly prepared by calcining cerium nitrate.

[0023] Comparative Example 2 The difference from Example 2 is that the activated carbon carrier is removed during the preparation of this negative oxygen ion agent.

[0024] Comparative Example 3 The difference from Example 2 is that the preparation process of this negative oxygen ion agent does not involve the addition of sodium silicate aqueous solution.

[0025] Comparative Example 4 The difference from Example 2 is that this negative oxygen ion agent has not undergone KH570 grafting modification treatment.

[0026] Performance testing The environmentally friendly coatings containing negative oxygen ions prepared in Examples 1-3 and Comparative Examples 1-4 were spin-coated onto glass slides and cured in a UV curing lamp box under standard conditions (temperature 23±2℃, humidity 50±5%RH) (dry film thickness 60μm). 1. Empty the residual air in the sealed chamber and reset the initial value of the detector to zero; place the coating sample to be tested into the test chamber and seal it for 30 minutes; for each group of samples, use the COM-3010PRO air negative oxygen ion detector probe 2cm away from the paint film surface, and select 5 points evenly from the center and four corners of each sample to read the steady-state negative oxygen ion concentration.

[0027] 2. Record the initial steady-state negative oxygen ion concentration of each group of samples, denoted as C0. Keep the samples in their original position in the sealed chamber, maintain constant temperature and humidity, and let them stand continuously for 24 hours. After 24 hours, measure the negative oxygen ion concentration of each group of samples again according to the steady-state concentration detection method, denoted as C1. Calculate the 24-hour release attenuation rate according to the formula: Attenuation rate (%) = [(C0-C1) / C0] × 100%.

[0028] 3. Conduct the coating adhesion test according to standard GB / T 9286-2021.

[0029] 4. Conduct pencil hardness testing according to standard GB / T 6739-2022.

[0030] The test results are shown in Table 1 below.

[0031] Table 1 The test results above show that the negative oxygen ion-containing coatings prepared in Examples 1-3 of this invention have good negative oxygen ion release performance, and the film layer formed has good hardness and adhesion. As the amount of modified negative oxygen ion agent added increases, the release source increases and the concentration of negative oxygen ions increases. The negative oxygen ion release attenuation rate of each comparative example is higher than that of the examples, indicating poor stability. Adding a rigid modified negative oxygen ion agent to UV polyurethane acrylate will significantly improve the modulus and hardness of the coating, but at the same time, the high filler content leads to a decrease in coating adhesion. Comparative Example 1: Nano-cerium oxide was prepared without coordination with 1,3,5-benzenetricarboxylic acid. Without coordination constraints, direct calcination of cerium nitrate easily forms large-sized, highly aggregated cerium oxide particles. The aggregated cerium oxide is unevenly dispersed in the composite system, further reducing the overall effective catalytic area and ultimately leading to a sharp drop in the concentration of negative oxygen ions. The surface active sites of large cerium oxide particles are easily covered by water vapor and impurities, and the aggregated structure is prone to local deactivation, resulting in poor stability of negative oxygen ion release and a significant increase in the decay rate. However, the coordination modification of cerium oxide mainly affects its catalytic activity and has little effect on the crosslinking density and compactness of the coating, so the pencil hardness remains unchanged. However, particle agglomeration leads to local interface defects and a decrease in adhesion.

[0032] Comparative Example 2: Removing the activated carbon carrier. The porous activated carbon structure can adsorb water vapor molecules in the air, providing sufficient reactants for the ionization reaction of cerium oxide / tourmaline. Removing the activated carbon leads to a decrease in the concentration of negative oxygen ions and an increase in the attenuation rate. At the same time, the activated carbon plays a skeletal supporting role in the system, which helps to improve the density and cross-linking degree of the coating film. After removal, the powder formability deteriorates, the coating density decreases, and therefore the pencil hardness decreases. In addition, the lack of a carrier weakens the interfacial bonding force between the negative oxygen ion agent and the resin, resulting in a decrease in adhesion.

[0033] In Comparative Example 3, without the addition of sodium silicate aqueous solution, the negative oxygen ion agent particles had a loose and easily broken structure, resulting in uneven dispersion in the coating. Some active components were encapsulated or lost by the resin, leading to a decrease in negative ion concentration. Furthermore, the loose structure easily caused rapid deactivation of active components, significantly increasing the attenuation rate. Without sodium silicate, the compatibility between the composite powder and the resin deteriorated, and the cohesive strength and interfacial adhesion of the coating film were severely insufficient, resulting in a decrease in pencil hardness and adhesion.

[0034] Comparative Example 4, without KH570 silane modification, resulted in powder agglomeration leading to uneven dispersion of active components, thus decreasing the concentration of negative ions, deteriorating long-term release stability, and increasing the decay rate. KH570 silane modification significantly improved the interfacial bonding force between the powder and the resin. Without modification, the interfacial tension between the powder and the resin was high, resulting in insufficient cohesive strength of the coating and insufficient adhesion to the substrate, thus reducing adhesion and hardness.

[0035] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A method for preparing an environmentally friendly coating containing negative oxygen ions, characterized in that, Includes the following steps: S1. After co-precipitation of the ligand and cerium source, nano-cerium oxide is obtained by calcination. S2. After the plant straw powder is impregnated with the activator and swollen, it is dried and then carbonized and activated under an inert atmosphere to obtain an activated carbon carrier. S3. Take the activated carbon carrier, nano-cerium oxide, nano-tourmaline powder, dispersant and deionized water, mix them, add sodium silicate aqueous solution, extrude granulation, heat preservation treatment, and obtain negative oxygen ion agent; S4. Take the negative oxygen ion agent and perform KH570 graft modification treatment to obtain a modified negative oxygen ion agent. S5. Take difunctional polyurethane acrylate, reactive monomer, reactive diluent, modified negative oxygen ion agent, wetting and dispersing agent, defoamer, leveling agent, antioxidant and photoinitiator, mix them in the dark and stir evenly to obtain an environmentally friendly coating containing negative oxygen ions.

2. The method for preparing an environmentally friendly coating containing negative oxygen ions according to claim 1, characterized in that, In step S1, the ligand is 1,3,5-benzenetricarboxylic acid; the concentration of cerium ions in the cerium source is 0.4-0.7 mol / L; the calcination refers to heating from room temperature to 300-400℃ at a rate of 3-5℃ / min and holding at that temperature for 1.5-2.5h.

3. The method for preparing an environmentally friendly coating containing negative oxygen ions according to claim 1, characterized in that, In step S2, the carbonization activation refers to heating to 500-600℃ at a rate of 5-10℃ / min and holding for 1.5-2.5h in a nitrogen atmosphere; the activator is a zinc chloride aqueous solution, and the ratio of plant straw powder to zinc chloride aqueous solution is 1g:4-5mL; the concentration of the zinc chloride aqueous solution is 3-5mol / L.

4. The method for preparing an environmentally friendly coating containing negative oxygen ions according to claim 1, characterized in that, In step S3, the mass ratio of the activated carbon carrier, nano-cerium oxide, nano-tourmaline powder, dispersant, deionized water, and sodium silicate aqueous solution is 50-60:5-8:25-30:0.4-0.6:20-28:4-6; the mass fraction of the sodium silicate aqueous solution is 30%, and the modulus is 2.4; the heat preservation treatment refers to keeping the temperature at 80℃ for 1.5-2.5h, then raising the temperature to 180-220℃ and keeping it at 180-220℃ for 2-3h; the dispersant is sodium polyacrylate.

5. The method for preparing an environmentally friendly coating containing negative oxygen ions according to claim 1, characterized in that, In step S4, the mass ratio of the negative oxygen ion agent to KH570 is 4-6:1.2-1.

4.

6. The method for preparing an environmentally friendly coating containing negative oxygen ions according to claim 1, characterized in that, In step S5, the mass ratio of the difunctional polyurethane acrylate, reactive monomer, reactive diluent, modified negative oxygen ion agent, photoinitiator, leveling agent, antioxidant, defoamer, and wetting and dispersing agent is 40-50:10-15:8-12:3-8:1.0-1.5:0.5-0.8:0.2-0.4:0.3-0.5:0.5-0.

8.

7. An environmentally friendly coating containing negative oxygen ions, characterized in that, It is prepared using the method for preparing an environmentally friendly coating containing negative oxygen ions as described in any one of claims 1-6.

8. The environmentally friendly coating containing negative oxygen ions according to claim 7, characterized in that, The leveling agent is BYK-333, the antioxidant is antioxidant 1010, the defoamer is BYK-019, the wetting and dispersing agent is BYK-190 dispersant, the active monomer is trimethylolpropane triacrylate, and the active diluent is 1,6-hexanediol diacrylate.

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