Dust-free easy-to-clean whiteboard material and method for making the same

Abstract

The application provides a dust-free and easy-to-clean whiteboard material and a preparation method thereof, and belongs to the technical field of materials. After C / N doped TiO2 mesoporous nanospheres are prepared, mixed with carbon quantum dots and sodium borohydride, and ball milled, the product is heated and treated, added into paint containing an aqueous acrylic emulsion, sprayed on a whiteboard substrate, and solidified, and then subjected to surface plasma treatment, washed, and dried to obtain the dust-free and easy-to-clean whiteboard material. The dust-free and easy-to-clean whiteboard material prepared by the application has good photocatalytic degradation and antibacterial effects, can better decompose ink residue of a paintbrush on the whiteboard, has good self-cleaning effect, prevents deep layer penetration of ink stains, and prevents dust adsorption, so that the whiteboard has the effects of easy-to-clean and dust-free.

Description

Technical Field

[0001] This invention relates to the field of materials technology, specifically to a dust-free, easy-to-clean whiteboard material and its preparation method. Background Technology

[0002] With the development of modern technology, green concepts such as "paperless," "dust-free," "environmentally friendly," and "healthy" have gradually entered people's lives. Whiteboards and whiteboard markers have emerged to replace traditional blackboards, avoiding the dust pollution caused by writing with chalk on blackboards and saving paper. People can apply whiteboard paint to relatively flat substrates (walls, wood surfaces, etc.) to create a whiteboard effect based on their own preferences and needs.

[0003] Currently, the whiteboard paints commonly used on the market include solvent-based two-component whiteboard paints and traditional water-based whiteboard paints. Although solvent-based whiteboard paints have an advantage in terms of service life, because they are two-component solvents, they emit an irritating odor during or after the coating process, and also contain volatile organic compounds that are harmful to human health. In addition, two-component systems also face problems such as complicated construction. Therefore, the defects of solvent-based whiteboard paints are very obvious, and their application areas are greatly limited.

[0004] Chinese patent publication CN104152002A discloses an epoxy blackboard paint with excellent writing performance, high hardness, good mechanical properties, strong adhesion, and the ability to prevent mold growth, as well as a good paint film effect. Chinese patent application 201010566670.1 discloses a UV-curable coating for whiteboards, which solves the defect of ink shrinkage when the paint film has high hardness, and has good repeated writing and erasing capabilities, as well as good weather resistance. However, these paint films have the problem that the writing on the whiteboard remains for a long time and becomes difficult to erase after drying. Summary of the Invention

[0005] The purpose of this invention is to propose a dust-free and easy-to-clean whiteboard material and its preparation method. It has good photocatalytic degradation and antibacterial effects, can effectively decompose ink residue from brushes on the whiteboard, has good self-cleaning effect, prevents ink stains from penetrating deeply, and prevents dust adsorption. Therefore, it is easy to clean and dust-free.

[0006] The technical solution of this invention is implemented as follows: This invention provides a method for preparing a dust-free and easy-to-clean whiteboard material. After preparing C / N-doped TiO2 mesoporous nanospheres, the nanospheres are mixed with carbon quantum dots and sodium borohydride and ball-milled. The mixture is then heated and the product is added to an aqueous acrylic emulsion paint. The mixture is then sprayed onto a whiteboard substrate, cured, and then subjected to surface plasma treatment, washed, and dried to obtain the dust-free and easy-to-clean whiteboard material.

[0007] As a further improvement to the present invention, the following steps are included: S1. Tetrabutyl titanate, melamine, hexadecylamine, potassium chloride, water and methanol were mixed evenly, stirred and reacted, allowed to stand, centrifuged and dried, the product was added to an ethanol aqueous solution, hydrothermally reacted, centrifuged, washed, dried and calcined to obtain C / N doped TiO2 mesoporous nanospheres. Lattice doping and crystal defects significantly alter the lattice, surface state, dispersion, strain, and electronic structure of nanomaterials, thereby affecting the photocatalytic pathway and performance. This invention, by doping TiO2 with C and N elements during its preparation, can narrow the band gap, improve light absorption efficiency, enhance carrier separation efficiency, and generate coupled states through C and N co-doping, resulting in a synergistic effect.

[0008] S2. Carbon quantum dots, sodium borohydride, and C / N-doped TiO2 mesoporous nanospheres were mixed and ball-milled, then heated in an inert gas atmosphere to obtain carbon quantum dots / doped TiO2 nanospheres. n Mesoporous nanospheres, n<2; This invention involves mixing carbon quantum dots and a reducing agent with C / N-doped TiO2 mesoporous nanospheres, followed by heating and reduction to prepare carbon quantum dot-doped TiO2 nanospheres with oxygen-containing defects. n Materials, through defect doping, can have their band structure tuned, extending the optical response from the ultraviolet to the near-infrared region; secondly, Ti 3+ Oxygen vacancies act as shallow donors, promoting rapid separation of photogenerated carriers and increasing their conductivity by creating localized states within the band gap. Third, the introduction of oxygen vacancies further alters the lattice spacing, disrupting the symmetry of the crystal structure and changing the electronic structure of the active sites. Modification of the active sites also affects the adsorption stability of the material surface. This leads to changes in the fabricated carbon quantum dots / doped TiO₂. n Mesoporous nanospheres exhibit excellent utilization efficiency in the visible light region, thus demonstrating superior photocatalytic degradation and antibacterial effects. Carbon quantum dots are stable under an inert atmosphere and can act as a structural protectant to prevent structural collapse. Simultaneously, they can absorb visible light and convert it into ultraviolet light waves usable by titanium dioxide, thereby synergistically enhancing the photocatalytic effect. Therefore, they can effectively decompose ink residue on whiteboards and possess good self-cleaning properties.

[0009] S3. Combine aqueous acrylic emulsion, film-forming agent, pH adjuster, additives, modifier, and carbon quantum dots / doped TiO2. n Mesoporous nanospheres are added to water and stirred until homogeneous to obtain a base coating. Carbon quantum dots / doped TiO nThe hydroxyl groups on the surface of mesoporous nanospheres can react with silane coupling agents, thereby improving their dispersibility and compatibility in coatings. They also have good mechanical modification effects. In addition, the nanosphere structure forms a "micro-nano" structure on the surface of the whiteboard substrate, which increases the roughness and allows the ink solvent to spread quickly but not penetrate, thus providing better writing performance.

[0010] S4. Spray a base paint onto the whiteboard substrate, cure it, and then treat the surface with plasma, wash it, and dry it to obtain a dust-free and easy-to-clean whiteboard material.

[0011] After plasma treatment, an ultra-thin oxide layer is formed on the surface, preventing ink stains from penetrating deeply. Cleaning only requires wiping the surface, while also strengthening the adhesion between the coating and the substrate. At the same time, it neutralizes surface static electricity, preventing dust adsorption.

[0012] As a further improvement of the present invention, the mass ratio of tetrabutyl titanate, melamine, hexadecylamine, potassium chloride and water is 10-14:1-2:3-4:0.02-0.05:5-6.

[0013] As a further improvement of the present invention, the stirring reaction time in step S1 is 1-3 hours, the standing time is 15-20 hours, the hydrothermal reaction temperature is 150-170°C, and the time is 12-18 hours.

[0014] As a further improvement of the present invention, the mass ratio of the carbon quantum dots, sodium borohydride and C / N doped TiO2 mesoporous nanospheres is 1-2:8-10:8-10.

[0015] As a further improvement of the present invention, the ball milling time in step S2 is 20-40 min; the heat treatment temperature is 200-250℃ and the time is 0.5-1.5 h.

[0016] As a further improvement of the present invention, the aqueous acrylic emulsion, film-forming agent, pH adjuster, additives, modifier, and carbon quantum dots / doped TiO2 are described. n The mass ratio of the mesoporous nanospheres is 60-70:3-5:0.1-0.5:1.5-2:0.1-0.3:8-10.

[0017] As a further improvement of the present invention, the aqueous acrylic emulsion is at least one of pure acrylic emulsion, styrene-acrylic emulsion, silicone-acrylic emulsion, and vinyl acetate-acrylic emulsion; the film-forming agent is selected from at least one of ethylene glycol butyl ether acetate, butylene glycol butyl ether acetate, or hexanediol butyl ether acetate; the pH adjuster is an organic amine; the additives include defoamers, rheology modifiers, and wetting agents; and the modifier is a silane coupling agent selected from at least one of KH550, KH602, and KH792.

[0018] As a further improvement of the present invention, the curing method in step S4 is to heat to 60-80℃ and cure for 1-2 hours; the parameters of the surface plasma treatment are: air flow rate 50-100mL / min, power 200-300W, vacuum degree 400-600Pa, and treatment time 1500-2000s.

[0019] This invention further protects a dust-free, easy-to-clean whiteboard material prepared by the above-described preparation method.

[0020] The present invention has the following beneficial effects: 1. The dust-free and easy-to-clean whiteboard material prepared by the present invention, through the reduction of C / N doped TiO2 mesoporous nanospheres and simultaneous composite with carbon quantum dots, has a good utilization rate in the visible light region, and exhibits good photocatalytic degradation, antibacterial and other effects. It can effectively decompose the ink residue of the pen on the whiteboard and has a good self-cleaning effect.

[0021] 2. The present invention relates to carbon quantum dots / doped TiO₂ n After being treated with a modifier, mesoporous nanospheres can be more dispersed in coatings, forming a "micro-nano" structure that improves roughness and provides better writing performance. After plasma treatment, an ultra-thin oxide layer is formed on the surface to prevent ink from penetrating deeply. At the same time, it neutralizes surface static electricity and prevents dust adsorption, thus providing easy cleaning and dust-free effects. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 The carbon quantum dots / doped TiO2 prepared in Example 1 n TEM image of mesoporous nanospheres; Figure 2 To prepare TiO2 mesoporous nanospheres, C / N-doped TiO2 mesoporous nanospheres and carbon quantum dots / doped TiO2 nanospheres n Steady-state photoluminescence spectrum of mesoporous nanospheres. Detailed Implementation

[0024] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] Carbon quantum dots, brownish-black powder, particle size 2-5nm.

[0026] Example 1 This embodiment provides a method for preparing a dust-free and easy-to-clean whiteboard material, including the following steps: S1. Mix 10g tetrabutyl titanate, 1g melamine, 3g hexadecylamine, 0.02g potassium chloride, 5mL water and 700mL methanol evenly, stir and react for 1h, let stand for 15h, centrifuge, dry, add the product to 800mL ethanol aqueous solution (volume ratio 1:1), hydrothermally react at 150℃ for 12h, centrifuge, wash, dry, calcine at 400℃ for 2h to obtain C / N doped TiO2 mesoporous nanospheres; S2. Mix 1g of carbon quantum dots, 8g of sodium borohydride, and 8g of C / N-doped TiO2 mesoporous nanospheres and ball mill for 20 min. Then, heat to 200℃ in a nitrogen atmosphere and treat for 1.5 h to obtain carbon quantum dots / doped TiO2 nanospheres. n Mesoporous nanospheres, n<2 Figure 1 The TEM image shows that the nanospheres have a particle size between 400 and 600 nm. Figure 2 The prepared TiO2 mesoporous nanospheres (prepared in step S1 of Comparative Example 1), C / N-doped TiO2 mesoporous nanospheres (prepared in step S1 of this embodiment), and carbon quantum dots / doped TiO2 nanospheres were prepared. n Steady-state photoluminescence spectrum of mesoporous nanospheres (prepared in step S2 of this embodiment). The main peak around 415 nm in the steady-state photoluminescence spectrum is due to the interband transition of anatase TiO2. The emission band around 520 nm is formed by the superposition of captured excitons and various defect-related emission bands. The lower the photoluminescence intensity, the lower the photoelectron-hole recombination rate, and the higher the photocatalytic efficiency. C / N-doped TiO2 mesoporous nanospheres and carbon quantum dots / doped TiO2 nanospheres are also mentioned. n The luminescence intensity of mesoporous nanospheres was lower than that of TiO2 mesoporous nanospheres, indicating that their photocatalytic efficiency was higher than that of TiO2 mesoporous nanospheres. Among these, carbon quantum dots / doped TiO2 nanospheres exhibited higher luminescence intensity. n Mesoporous nanospheres exhibit the lowest luminescence intensity, indicating that carbon quantum dots / doped TiO₂ have the highest luminescence intensity. n Mesoporous nanospheres have the most appropriate defect content and the least strain, which effectively reduces the recombination of photo-induced charge carriers and can maximize the utilization of light energy to achieve high photocatalytic efficiency.

[0027] S3. Mix 60g of aqueous acrylic emulsion (Yoshida Chemical E0503), 3g of hexanediol butyl ether acetate, 0.1g of triethylamine, 1.5g of additives, 0.1g of silane coupling agent KH550, and 8g of carbon quantum dots / doped TiO2. nMesoporous nanospheres were added to 100 mL of water and stirred until homogeneous to obtain the base coating. The additives include polysiloxane emulsion defoamers, cellulose ether rheology modifiers, and organosilicon surfactant wetting agents in a mass ratio of 1:1:1.

[0028] S4. Spray a base coat of paint onto the whiteboard substrate at a rate of 200 mL / m. 2 After curing at 60℃ for 2 hours, the surface is treated with plasma, washed, and dried to obtain a dust-free and easy-to-clean whiteboard material. The parameters for surface plasma treatment were: air flow rate 50 mL / min, power 200 W, vacuum degree 400 Pa, and treatment time 1500 s.

[0029] Example 2 This embodiment provides a method for preparing a dust-free and easy-to-clean whiteboard material, including the following steps: S1. Mix 14g tetrabutyl titanate, 2g melamine, 4g hexadecylamine, 0.05g potassium chloride, 6mL water and 800mL methanol evenly, stir and react for 3h, let stand for 20h, centrifuge, dry, add the product to 800mL ethanol aqueous solution (volume ratio 1:1), hydrothermally react at 170℃ for 18h, centrifuge, wash, dry, calcine at 500℃ for 2h to obtain C / N doped TiO2 mesoporous nanospheres; S2. 2g of carbon quantum dots, 10g of sodium borohydride, and 10g of C / N-doped TiO2 mesoporous nanospheres were mixed and ball-milled for 40 min. The mixture was then heated to 250℃ in a nitrogen atmosphere and treated for 0.5 h to obtain carbon quantum dots / doped TiO2 nanospheres. n Mesoporous nanospheres, n<2; S3. Mix 70g of aqueous acrylic emulsion (Yoshida Chemical E0503), 5g of butanediol butyl ether acetate, 0.5g of triethylamine, 2g of additives, 0.3g of silane coupling agent KH602, and 10g of carbon quantum dots / doped TiO2. n Mesoporous nanospheres were added to 100 mL of water and stirred until homogeneous to obtain the base coating. The additives include polysiloxane emulsion defoamers, cellulose ether rheology modifiers, and organosilicon surfactant wetting agents in a mass ratio of 1:1:1.

[0030] S4. Spray a base coat of paint onto the whiteboard substrate at a rate of 300 mL / m. 2 After curing at 80℃ for 2 hours, the surface is treated with plasma, washed, and dried to obtain a dust-free and easy-to-clean whiteboard material. The parameters for surface plasma treatment were: air flow rate 100 mL / min, power 300 W, vacuum degree 600 Pa, and treatment time 2000 s.

[0031] Example 3 This embodiment provides a method for preparing a dust-free and easy-to-clean whiteboard material, including the following steps: S1. Mix 12g tetrabutyl titanate, 1.5g melamine, 3.5g hexadecylamine, 0.03g potassium chloride, 6mL water and 750mL methanol evenly, stir and react for 2h, let stand for 17h, centrifuge, dry, add the product to 800mL ethanol aqueous solution (volume ratio 1:1), hydrothermally react at 160℃ for 15h, centrifuge, wash, dry, calcine at 450℃ for 2h to obtain C / N doped TiO2 mesoporous nanospheres; S2. Mix 1.5g carbon quantum dots, 9g sodium borohydride, and 9g C / N-doped TiO2 mesoporous nanospheres and ball mill for 30 min. Then, heat to 220℃ in a nitrogen atmosphere and treat for 1 h to obtain carbon quantum dots / doped TiO2 nanospheres. n Mesoporous nanospheres, n<2; S3. Mix 65g of aqueous acrylic emulsion (Yoshida Chemical E0503), 4g of ethylene glycol butyl ether acetate, 0.3g of triethylamine, 1.7g of additives, 0.2g of silane coupling agent KH792, and 9g of carbon quantum dots / doped TiO2. n Mesoporous nanospheres were added to 100 mL of water and stirred until homogeneous to obtain the base coating. The additives include polysiloxane emulsion defoamers, cellulose ether rheology modifiers, and organosilicon surfactant wetting agents in a mass ratio of 1:1:1.

[0032] S4. Spray a base coat onto the whiteboard substrate at a rate of 250 mL / m. 2 After curing at 70℃ for 1.5 hours, the surface is treated with plasma, washed, and dried to obtain a dust-free and easy-to-clean whiteboard material. The parameters for surface plasma treatment were: air flow rate 70 mL / min, power 250 W, vacuum degree 500 Pa, and treatment time 1700 s.

[0033] Comparative Example 1 The difference from Example 3 is that melamine was not added in step S1.

[0034] Includes the following steps: S1. Mix 12g tetrabutyl titanate, 3.5g hexadecylamine, 0.03g potassium chloride, 6mL water and 750mL methanol evenly, stir and react for 2h, let stand for 17h, centrifuge, dry, add the product to 800mL ethanol aqueous solution (volume ratio 1:1), hydrothermally react at 160℃ for 15h, centrifuge, wash, dry, calcine at 450℃ for 2h to obtain TiO2 mesoporous nanospheres; S2. Mix 1.5g carbon quantum dots, 9g sodium borohydride, and 9g TiO2 mesoporous nanospheres and ball mill for 30 min. Then, heat to 220℃ and treat for 1 h in a nitrogen atmosphere to obtain carbon quantum dot / TiO2 nanospheres. n Mesoporous nanospheres, n<2; S3. Mix 65g of aqueous acrylic emulsion (Yoshida Chemical E0503), 4g of ethylene glycol butyl ether acetate, 0.3g of triethylamine, 1.7g of additives, 0.2g of silane coupling agent KH792, and 9g of carbon quantum dots / TiO2. n Mesoporous nanospheres were added to 100 mL of water and stirred until homogeneous to obtain the base coating. The additives include polysiloxane emulsion defoamers, cellulose ether rheology modifiers, and organosilicon surfactant wetting agents in a mass ratio of 1:1:1.

[0035] S4. Spray a base coat onto the whiteboard substrate at a rate of 250 mL / m. 2 After curing at 70℃ for 1.5 hours, the surface is treated with plasma, washed, and dried to obtain a dust-free and easy-to-clean whiteboard material. The parameters for surface plasma treatment were: air flow rate 70 mL / min, power 250 W, vacuum degree 500 Pa, and treatment time 1700 s.

[0036] Comparative Example 2 The difference from Example 3 is that carbon quantum dots were not added in step S2.

[0037] Includes the following steps: S1. Mix 12g tetrabutyl titanate, 1.5g melamine, 3.5g hexadecylamine, 0.03g potassium chloride, 6mL water and 750mL methanol evenly, stir and react for 2h, let stand for 17h, centrifuge, dry, add the product to 800mL ethanol aqueous solution (volume ratio 1:1), hydrothermally react at 160℃ for 15h, centrifuge, wash, dry, calcine at 450℃ for 2h to obtain C / N doped TiO2 mesoporous nanospheres; S2. Mix 9g of sodium borohydride and 9g of C / N-doped TiO2 mesoporous nanospheres and ball mill for 30 min. Then, heat to 220℃ in a nitrogen atmosphere and treat for 1 h to obtain doped TiO2 nanospheres. n Mesoporous nanospheres, n<2; S3. Mix 65g of aqueous acrylic emulsion (Yoshida Chemical E0503), 4g of ethylene glycol butyl ether acetate, 0.3g of triethylamine, 1.7g of additives, 0.2g of silane coupling agent KH792, and 9g of doped TiO2. n Mesoporous nanospheres were added to 100 mL of water and stirred until homogeneous to obtain the base coating. The additives include polysiloxane emulsion defoamers, cellulose ether rheology modifiers, and organosilicon surfactant wetting agents in a mass ratio of 1:1:1.

[0038] S4. Spray a base coat onto the whiteboard substrate at a rate of 250 mL / m. 2 After curing at 70℃ for 1.5 hours, the surface is treated with plasma, washed, and dried to obtain a dust-free and easy-to-clean whiteboard material. The parameters for surface plasma treatment were: air flow rate 70 mL / min, power 250 W, vacuum degree 500 Pa, and treatment time 1700 s.

[0039] Comparative Example 3 The difference from Example 3 is that sodium borohydride was not added in step S2, and heating reduction was not performed.

[0040] Includes the following steps: S1. Mix 12g tetrabutyl titanate, 1.5g melamine, 3.5g hexadecylamine, 0.03g potassium chloride, 6mL water and 750mL methanol evenly, stir and react for 2h, let stand for 17h, centrifuge, dry, add the product to 800mL ethanol aqueous solution (volume ratio 1:1), hydrothermally react at 160℃ for 15h, centrifuge, wash, dry, calcine at 450℃ for 2h to obtain C / N doped TiO2 mesoporous nanospheres; S2. Mix 1.5g of carbon quantum dots and 9g of C / N-doped TiO2 mesoporous nanospheres and ball mill for 30min to obtain the composite. S3. Add 65g of waterborne acrylic emulsion (Yoshida Chemical E0503), 4g of ethylene glycol butyl ether acetate, 0.3g of triethylamine, 1.7g of additives, 0.2g of silane coupling agent KH792 and 9g of complex to 100mL of water, stir and mix evenly to obtain the base paint. The additives include polysiloxane emulsion defoamers, cellulose ether rheology modifiers, and organosilicon surfactant wetting agents in a mass ratio of 1:1:1.

[0041] S4. Spray a base coat onto the whiteboard substrate at a rate of 250 mL / m. 2 After curing at 70℃ for 1.5 hours, the surface is treated with plasma, washed, and dried to obtain a dust-free and easy-to-clean whiteboard material. The parameters for surface plasma treatment were: air flow rate 70 mL / min, power 250 W, vacuum degree 500 Pa, and treatment time 1700 s.

[0042] Comparative Example 4 The difference from Example 3 is that step S2 was not performed.

[0043] Includes the following steps: S1. Mix 12g tetrabutyl titanate, 1.5g melamine, 3.5g hexadecylamine, 0.03g potassium chloride, 6mL water and 750mL methanol evenly, stir and react for 2h, let stand for 17h, centrifuge, dry, add the product to 800mL ethanol aqueous solution (volume ratio 1:1), hydrothermally react at 160℃ for 15h, centrifuge, wash, dry, calcine at 450℃ for 2h to obtain C / N doped TiO2 mesoporous nanospheres; S2. Add 65g of waterborne acrylic emulsion (Yoshida Chemical E0503), 4g of ethylene glycol butyl ether acetate, 0.3g of triethylamine, 1.7g of additives, 0.2g of silane coupling agent KH792 and 9g of C / N doped TiO2 mesoporous nanospheres to 100mL of water, stir and mix evenly to obtain the base paint. The additives include polysiloxane emulsion defoamers, cellulose ether rheology modifiers, and organosilicon surfactant wetting agents in a mass ratio of 1:1:1.

[0044] S3. Spray a base coat onto the whiteboard substrate at a rate of 250 mL / m. 2 After curing at 70℃ for 1.5 hours, the surface is treated with plasma, washed, and dried to obtain a dust-free and easy-to-clean whiteboard material. The parameters for surface plasma treatment were: air flow rate 70 mL / min, power 250 W, vacuum degree 500 Pa, and treatment time 1700 s.

[0045] Comparative Example 5 The difference from Example 3 is that plasma treatment was not performed in step S4.

[0046] Includes the following steps: S1. Mix 12g tetrabutyl titanate, 1.5g melamine, 3.5g hexadecylamine, 0.03g potassium chloride, 6mL water and 750mL methanol evenly, stir and react for 2h, let stand for 17h, centrifuge, dry, add the product to 800mL ethanol aqueous solution (volume ratio 1:1), hydrothermally react at 160℃ for 15h, centrifuge, wash, dry, calcine at 450℃ for 2h to obtain C / N doped TiO2 mesoporous nanospheres; S2. Mix 1.5g carbon quantum dots, 9g sodium borohydride, and 9g C / N-doped TiO2 mesoporous nanospheres and ball mill for 30 min. Then, heat to 220℃ in a nitrogen atmosphere and treat for 1 h to obtain carbon quantum dots / doped TiO2 nanospheres. n Mesoporous nanospheres, n<2; S3. Mix 65g of aqueous acrylic emulsion (Yoshida Chemical E0503), 4g of ethylene glycol butyl ether acetate, 0.3g of triethylamine, 1.7g of additives, 0.2g of silane coupling agent KH792, and 9g of carbon quantum dots / doped TiO2.n Mesoporous nanospheres were added to 100 mL of water and stirred until homogeneous to obtain the base coating. The additives include polysiloxane emulsion defoamers, cellulose ether rheology modifiers, and organosilicon surfactant wetting agents in a mass ratio of 1:1:1.

[0047] S4. Spray a base coat onto the whiteboard substrate at a rate of 250 mL / m. 2 After curing at 70℃ for 1.5 hours, a dust-free and easy-to-clean whiteboard material is obtained.

[0048] Test Example 1 The dust-free and easy-to-clean whiteboard materials prepared in Examples 1-3 and Comparative Examples 1-5 were subjected to performance tests, and the results are shown in Table 1.

[0049] (1) Adhesion index: Refer to the national standard GB / T9286 "Cross-cut test of paint and varnish film"; (2) Ink shrinkage: How the ink shrinks when the whiteboard marker is writing on the template: 0 points - the whiteboard marker cannot write on it; 1 point - the whiteboard marker can write, but some areas will shrink severely; 2 points - the whiteboard marker can write, but some areas will shrink slightly; 3 points - the whiteboard marker can write, and there is no ink shrinkage at all.

[0050] (3) Antibacterial properties: Refer to the national standard GB / T21866-2008 "Determination of antibacterial properties and antibacterial effects of antibacterial coatings (films)"; the bacterial species is ATCC25922 Escherichia coli, and the test time is 1 month later.

[0051] (4) Stain resistance: How well carbon black powder leaves stains when wiped with a paper towel: 0 points - carbon black powder cannot be wiped clean; 1 point - carbon black powder can be wiped vigorously with a wet paper towel and less than 10% of the residue remains; 2 points - carbon black powder can be wiped with a wet paper towel and no residue remains; 3 points - carbon black powder can be wiped vigorously with a dry paper towel and less than 10% of the residue remains; 4 points - carbon black powder can be wiped vigorously with a dry paper towel and no residue remains; 5 points - carbon black powder can be easily wiped with a dry paper towel and no residue remains.

[0052] Table 1

[0053] As can be seen from the table above, the dust-free and easy-to-clean whiteboard materials prepared in Examples 1-3 of the present invention have good comprehensive performance.

[0054] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing a dust-free and easy-to-clean whiteboard material, characterized in that, C / N-doped TiO2 mesoporous nanospheres were prepared using tetrabutyl titanate, melamine, hexadecylamine, potassium chloride, water, and methanol. These nanospheres were then mixed with carbon quantum dots and sodium borohydride, ball-milled, and heat-treated to obtain carbon quantum dot / doped TiO2 nanospheres. n Mesoporous nanospheres, n<2, products: carbon quantum dots / doped TiO n Mesoporous nanospheres are added to an aqueous acrylic emulsion paint, sprayed onto a whiteboard substrate, cured, and then subjected to surface plasma treatment, washed, and dried to obtain a dust-free and easy-to-clean whiteboard material.

2. The preparation method according to claim 1, characterized in that, Includes the following steps: S1. Tetrabutyl titanate, melamine, hexadecylamine, potassium chloride, water and methanol were mixed evenly, stirred and reacted, allowed to stand, centrifuged and dried, the product was added to an ethanol aqueous solution, hydrothermally reacted, centrifuged, washed, dried and calcined to obtain C / N doped TiO2 mesoporous nanospheres. S2. Carbon quantum dots, sodium borohydride, and C / N-doped TiO2 mesoporous nanospheres were mixed and ball-milled, then heated in an inert atmosphere to obtain carbon quantum dots / doped TiO2 nanospheres. n Mesoporous nanospheres, n<2; S3. Combine aqueous acrylic emulsion, film-forming agent, pH adjuster, additives, modifier, and carbon quantum dots / doped TiO2. n Mesoporous nanospheres are added to water and stirred until homogeneous to obtain a base coating. S4. Spray a base paint onto the whiteboard substrate, cure it, and then treat the surface with plasma, wash it, and dry it to obtain a dust-free and easy-to-clean whiteboard material.

3. The preparation method according to claim 2, characterized in that, The mass ratio of tetrabutyl titanate, melamine, hexadecylamine, potassium chloride, and water is 10-14:1-2:3-4:0.02-0.05:5-6.

4. The preparation method according to claim 2, characterized in that, The stirring reaction time in step S1 is 1-3 hours, the settling time is 15-20 hours, the hydrothermal reaction temperature is 150-170℃, and the time is 12-18 hours.

5. The preparation method according to claim 2, characterized in that, The mass ratio of the carbon quantum dots, sodium borohydride, and C / N-doped TiO2 mesoporous nanospheres is 1-2:8-10:8-10.

6. The preparation method according to claim 2, characterized in that, The ball milling time in step S2 is 20-40 min; the heat treatment temperature is 200-250℃ and the time is 0.5-1.5 h.

7. The preparation method according to claim 2, characterized in that, The aqueous acrylic emulsion, film-forming agent, pH adjuster, additives, modifier, and carbon quantum dots / doped TiO2 are described. n The mass ratio of the mesoporous nanospheres is 60-70:3-5:0.1-0.5:1.5-2:0.1-0.3:8-10.

8. The preparation method according to claim 2, characterized in that, The aqueous acrylic emulsion is at least one of pure acrylic emulsion, styrene-acrylic emulsion, silicone-acrylic emulsion, and vinyl acetate-acrylic emulsion; the film-forming agent is selected from at least one of ethylene glycol butyl ether acetate, butylene glycol butyl ether acetate, or hexanediol butyl ether acetate; the pH adjuster is an organic amine; the additives include defoamers, rheology modifiers, and wetting agents; the modifier is a silane coupling agent selected from at least one of KH550, KH602, and KH792.

9. The preparation method according to claim 2, characterized in that, The curing method described in step S4 is to heat to 60-80℃ and cure for 1-2 hours; the parameters for the surface plasma treatment are: air flow rate 50-100mL / min, power 200-300W, vacuum degree 400-600Pa, and treatment time 1500-2000s.

10. A dust-free, easy-to-clean whiteboard material prepared by the preparation method according to any one of claims 1-9.

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