Long-lasting photocatalytic coating and method for its preparation and use

Abstract

The application provides a long-acting photocatalyst coating, a manufacturing method and application thereof. The long-acting photocatalyst coating comprises a substrate, an inorganic coating arranged on the surface of the substrate, and a nano-titanium oxide coating arranged on the surface of the inorganic coating. The preparation steps comprise: arranging the inorganic coating on the surface of the substrate; arranging the nano-titanium oxide coating on the surface of the inorganic coating when the inorganic coating is in a wet state; the nano-titanium oxide coating is a water or alcohol dispersion of nano-titanium oxide; the nano-titanium oxide coating is fused with the inorganic coating, dried, and the long-acting photocatalyst coating is obtained. The technical problem to be solved by the application is how to uniformly disperse nano-titanium oxide particles on the surface of an object, so that the long-acting photocatalyst coating has photocatalyst function and is durable and not easy to fall off, thereby being more suitable for practical use.

Description

Technical Field

[0001] This invention belongs to the field of functional coating manufacturing technology, and in particular relates to a long-lasting photocatalytic coating, its manufacturing method, and its application. Background Technology

[0002] Photocatalyst is a general term for photocatalytic semiconductor materials, represented by nano-sized titanium dioxide. It is coated on the surface of a substrate and, under the action of ultraviolet light, produces a strong catalytic degradation function. It can effectively degrade toxic and harmful gases in the air, effectively kill a variety of bacteria, and decompose and render harmless the toxins released by bacteria or fungi. It also has functions such as formaldehyde removal, deodorization, anti-fouling, and air purification.

[0003] Most commercially available photocatalysts disperse nano-titanium dioxide photocatalyst particles along with other additives in resins or emulsions. The resin or emulsion serves two purposes: dispersing the photocatalyst particles and acting as a binder to firmly adhere them to the object's surface. However, the encapsulation in resin or emulsion results in poor sterilization and disinfection effects. Furthermore, under light exposure, the photocatalyst reacts with organic substances like resins or emulsions, damaging the binder and causing the coating to fail, thus preventing long-lasting photocatalytic effects. Summary of the Invention

[0004] The main objective of this invention is to provide a long-lasting photocatalytic coating, its manufacturing method, and its application. The technical problem to be solved is how to uniformly disperse nano-titanium oxide particles on the surface of an object so that it not only has photocatalytic function but is also durable and will not peel off, thus making it more suitable for practical use.

[0005] The objective of this invention and the technical problem it solves are achieved through the following technical solution. A long-lasting photocatalytic coating according to this invention comprises:

[0006] Base;

[0007] An inorganic coating is disposed on the surface of the substrate; the inorganic coating includes a silicon oxide network structure.

[0008] A nano-titanium oxide coating is disposed on the surface of the inorganic coating.

[0009] The objectives of this invention and the technical problems it addresses can be further achieved by the following technical measures.

[0010] Preferably, in the aforementioned long-lasting photocatalytic coating, the thickness of the nano-titanium oxide coating is ≤100nm; and the particle size of the nano-titanium oxide particles in the nano-titanium oxide coating is 5-100nm.

[0011] Preferably, in the aforementioned long-lasting photocatalytic coating, the thickness of the nano-titanium oxide coating is ≤50nm; and the particle size of the nano-titanium oxide particles in the nano-titanium oxide coating is 5-50nm.

[0012] Preferably, in the aforementioned long-lasting photocatalytic coating, the raw materials for forming the inorganic coating include: 39-59 wt% organoalkoxysilane, 39-59 wt% silica sol, and 0.5-2 wt% functional additives; the total amount of the organoalkoxysilane, silica sol, and functional additives is 100%; the organoalkoxysilane has the molecular formula R 1 m Si(OR 2 ) 4-m Indicates; the R 1 Selected from alkyl groups; the R 2 Selected from alkyl groups; the general formula of the alkyl group is C0. n H 2n+1 Where n is a positive integer from 1 to 10; the R 1 and the OR 2 The total number is 4, and m is a natural number from 0 to 3.

[0013] Preferably, in the aforementioned long-lasting photocatalytic coating, the raw materials of the coating forming the inorganic coating include: 70-80 wt% solution; 5-10 wt% functional additives selected from potassium titanate, alumina, or a combination thereof; 10-20 wt% inorganic pigment; and 0.5-2.0 wt% other functional additives. The raw materials of the solution include: 30-40 wt% organoalkoxysilane, 15-20 wt% organic solvent, and 25-30 wt% silica sol. The organoalkoxysilane has the molecular formula R... 1 m Si(OR 2 ) 4-m Indicates; the R 1 Selected from alkyl groups; the R 2 Selected from alkyl groups; the general formula of the alkyl group is C0. n H 2n+1 Where n is a positive integer from 1 to 10; the R 1 and the OR 2 The total quantity is 4, and m is a natural number from 0 to 3; the above percentages are the mass percentages of each raw material in the total weight of the inorganic coating.

[0014] Preferably, in the aforementioned long-lasting photocatalytic coating, the raw materials for forming the inorganic coating include: 30-99.9% inorganic resin; 0.1-70% silicon nitride; 0-10% functional additives; 0-18% inorganic pigments; and 0-2% other functional additives; the total amount of the coating is 100%; wherein the inorganic resin is obtained by mixing and reacting an organoalkoxysilane, an organic solvent, and a silica sol, removing alcohol, and adding deionized water; the mass ratio of the organoalkoxysilane, organic solvent, and silica sol is 1-1.6:0.5-0.8:1; the organoalkoxysilane has the molecular formula R 1 m Si(OR 2 ) 4-m Indicates; the R 1 Selected from alkyl groups; the R 2 Selected from alkyl groups; the general formula of the alkyl group is C0. n H 2n+1 Where n is a positive integer from 1 to 10; the R 1 and the OR 2 The total quantity is 4, and m is a natural number from 0 to 3; the inorganic resin is an acidic cationic system; the VOC content of the inorganic resin is ≤10% by mass percentage; the functional additive is selected from at least one of potassium titanate, alumina and nano-silica.

[0015] Preferably, in the aforementioned long-lasting photocatalytic coating, the coating forming the nano-titanium oxide coating is an aqueous and / or alcoholic dispersion of nano-titanium oxide.

[0016] The objective of this invention and the technical problem it solves are further achieved by the following technical solution. A method for preparing a long-lasting photocatalytic coating according to this invention includes the following steps:

[0017] S11 applies inorganic coating to the surface of the substrate;

[0018] S12 When the inorganic coating is in a wet state, a nano-titanium oxide coating is applied to the surface of the inorganic coating; the nano-titanium oxide coating is an aqueous and / or alcoholic dispersion of nano-titanium oxide.

[0019] S13 nano-titanium oxide coating is fused with inorganic coating and dried to obtain a long-lasting photocatalytic coating.

[0020] The objectives of this invention and the technical problems it addresses can be further achieved by the following technical measures.

[0021] Preferably, in the aforementioned preparation method, the inorganic coating being in a wet state refers to the state when the inorganic coating has not yet dried to the touch.

[0022] The objective of this invention and the solution to its technical problems are also achieved by the following technical solution: The application of a long-lasting photocatalytic coating proposed in this invention in the fields of sterilization, disinfection, or self-cleaning.

[0023] By employing the above technical solution, the long-lasting photocatalytic coating, its manufacturing method, and its application proposed in this invention have at least the following advantages:

[0024] The long-lasting photocatalytic coating, its manufacturing method, and its application provided by this invention involve setting an inorganic coating on a substrate material, and then setting a nano-titanium oxide coating on the inorganic coating. By limiting the preparation process of setting the nano-titanium oxide coating while the inorganic coating is still wet, the nano-titanium oxide particles in the nano-titanium oxide coating can be uniformly spread on the surface of the inorganic coating, overcoming the defect in the prior art that nano-titanium oxide particles are difficult to spread uniformly on the surface of an object. Regarding the applicant's discovery, the applicant speculates that the reason may be as follows: Since the inorganic coating that forms the inorganic coating includes organic alkoxysilanes and silica sols, the two can form water and / or alcohol solvents during the self-condensation reaction; the nano-titanium oxide coating that forms the nano-titanium oxide coating is a water and / or alcohol dispersion of nano-titanium oxide, and the nano-titanium oxide coating is set when the inorganic coating is still wet, the water and / or alcohol solvents added to the inorganic coating or generated by the self-condensation reaction and the dispersion medium water and / or alcohol solvents in the nano-titanium oxide dispersion can be mixed under the action of water-alcohol solvent mutual wetting, so that the nano-titanium oxide particles in the dispersion are uniformly spread on the surface of the inorganic coating by the liquid phase fusion method. The above-mentioned technical solution of the present invention allows nano-titanium oxide particles to be uniformly spread on the surface of an inorganic coating, and the two are completely fused together before drying. On the one hand, the nano-titanium oxide particles can be physically embedded in the inorganic coating; on the other hand, the titanium element in the nano-titanium oxide particles can exist in a tetravalent state, and it is chemically bonded to the silicon-oxygen bonds in the silicon oxide network structure of the inorganic coating, so that the nano-titanium oxide particles are firmly bonded to the surface of the inorganic coating. After the two are fused together and dried, the nano-titanium oxide particles are firmly bonded to the surface of the object, forming a long-lasting photocatalytic coating. At the same time, since the preparation process involves first preparing the inorganic coating and then placing the nano-titanium oxide particles on the surface of the inorganic coating, the nano-titanium oxide particles are in an upper position, which can effectively avoid the nano-titanium oxide particles being embedded, thereby greatly avoiding or reducing the loss of the technical effect of the nano-titanium oxide particles as a photocatalyst and the efficiency of sterilization, disinfection, and decomposition of organic pollutants. Furthermore, since the bonding medium between the substrate surface and the nano-titanium oxide particles is an inorganic coating, it can completely prevent the nano-titanium oxide particles from acting on the bonding medium and being damaged when they decompose organic matter under light. This makes the inorganic coating difficult to damage, greatly extending its bonding and fixing time for the nano-titanium oxide particles, thereby greatly extending the service life of the nano-titanium oxide particles as a photocatalyst, and enabling them to effectively perform their bactericidal, disinfecting, and organic pollutant decomposition functions for a long time.

[0025] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, the preferred embodiments of the present invention are described in detail below. Attached Figure Description

[0026] Figure 1 These are the energy dispersive spectroscopy (EDS) spectra of the inorganic coatings and varnishes prepared in Examples 1-3 of this invention. Detailed Implementation

[0027] To further illustrate the technical means and effects adopted by the present invention to achieve the intended purpose, the following detailed description, in conjunction with preferred embodiments, details the specific implementation, structure, features, and effects of a long-lasting photocatalytic coating and its manufacturing method and application based on the present invention.

[0028] This invention proposes a long-lasting photocatalytic coating, which sequentially comprises a substrate, an inorganic coating, and a nano-titanium oxide coating. Wherein:

[0029] The substrate is primarily used as a carrier for the long-lasting photocatalytic coating. This carrier can be any organic or inorganic material, such as glass, plastic, paint, or metal, as long as it can support the coating; this invention does not impose any specific limitations. Because photocatalysts can decompose organic matter under light, they have been limited to applications on surfaces of non-organic materials such as glass and metal for many years. However, this invention, by first setting an inorganic coating on the substrate surface, physically isolates and blocks the reaction of the nano-titanium oxide coating on the substrate. This allows the long-lasting photocatalytic coating of this invention to be widely applied to various organic and inorganic materials, greatly expanding the application scenarios of photocatalysts. In other words, the technical solution of this invention can not only set the long-lasting photocatalytic coating on the surfaces of glass, metal, and stainless steel, but also on organic coatings, such as existing automotive paint and train paint, to achieve a self-cleaning effect.

[0030] The inorganic coating is disposed on the surface of the substrate; the nano-titanium oxide coating is disposed on the surface of the inorganic coating. The inorganic coating includes a silicon oxide network structure. It should be specifically noted that the silicon oxide included in the inorganic coating in this invention is not silicon oxide particles, but a silicon-oxygen-silicon network structure formed by the self-condensation of silanol; to illustrate the morphology and structure of the silicon oxide in the inorganic coating of this invention, in a specific embodiment of this invention, the inorganic coating is made into a varnish, and after its self-condensation to form a film, energy dispersive spectroscopy (EDS) analysis is performed on the formed inorganic coating, and the spectrum is attached. Figure 1 As shown in Table 1, the results of the energy dispersive spectroscopy (EDS) component analysis are as follows:

[0031] Table 1

[0032] OK 33.26 46.66 Si K 66.74 53.34

[0033] Note: The testing area is the surface of the transparent coating.

[0034] The spectrum was processed as follows:

[0035] Potentially overlooked peak: 2.150 keV

[0036] Processing options: All analyzed elements (normalized)

[0037] Repeated 3 times

[0038] Standard samples: O SiO2, Si SiO2

[0039] To avoid the nano-titanium oxide particles being encapsulated and thus affecting their photocatalytic effect, the coating used to form the nano-titanium oxide coating is preferably an aqueous and / or alcoholic dispersion of nano-titanium oxide, without the addition of other pigments, fillers, resins, or other raw materials. In this invention, the nano-titanium oxide particles are in a dispersed rather than dissolved state in the aqueous and / or alcoholic solvents. Although the resulting dispersion appears transparent, it is actually a suspension. Alternatively, the nano-titanium oxide particles are in a titanium sol state similar to a silica sol structure in the aqueous and / or alcoholic solvents. Although the resulting dispersion appears transparent, it is actually a sol. While the solid content of the nano-titanium oxide dispersion may affect the gloss of the coating, it does not affect its photocatalytic effect. Therefore, this invention does not strictly limit the solid content of the dispersion, as long as it allows for stable storage and easy, uniform spreading on the surface of the inorganic coating.

[0040] This invention specifies that the nano-titanium oxide coating is applied to the surface of an inorganic coating. This is partly because the applicant surprisingly discovered that a dispersion of nano-titanium oxide can easily and uniformly spread on the surface of a still-wet inorganic coating. Although the exact mechanism is not yet fully determined, the applicant speculates that the possible reasons are: the solvent used in the inorganic coating forming the inorganic coating is an alcohol solvent; or, even without adding any solvent, the inorganic coating will generate alcohol solvents during the silanol self-condensation reaction. The nano-titanium oxide coating forming the nano-titanium oxide coating is an aqueous and / or alcohol dispersion of nano-titanium oxide. Due to the physical and / or chemical properties of alcohol solvents and water, they can mutually wet under wet conditions. During the fusion process, the nano-titanium oxide particles in the dispersion are evenly spread on the surface of the inorganic coating, overcoming the technical difficulty of the nano-titanium oxide particles being difficult to spread evenly on the surface of an object; it may also be due to the positive and negative charge interaction between the inorganic coating and the nano-titanium oxide dispersion, or the presence of anionic and cation interaction; on the other hand, the unique composition of the inorganic coating itself is different from that of general resins, emulsions and other organic binders, and it will not be decomposed and destroyed by the nano-titanium oxide particles under the action of light, so that it can maintain the bonding and fixing effect of the inorganic coating on the nano-titanium oxide particles for a long time, and exert the photocatalytic effect for a long time. That is, the long-lasting photocatalytic coating of the present invention is a semi-permanent coating.

[0041] To enable the long-lasting photocatalytic coating of this invention to be applied to the surface of transparent materials such as glass, and to avoid or reduce the impact on the transparency of the substrate, the inorganic coating of this invention is preferably a transparent coating, and the nano-titanium oxide coating is also a transparent coating. Preferably, the raw materials for forming the inorganic coating include: 39-59 wt% organoalkoxysilane, 39-59 wt% silica sol, and 0.5-2 wt% functional additives; the total amount of the organoalkoxysilane, silica sol, and functional additives is 100%; the organoalkoxysilane has the molecular formula R... 1 m Si(OR 2 ) 4-m Indicates; the R 1 Selected from alkyl groups; the R 2 Selected from alkyl groups; the general formula of the alkyl group is C0. n H 2n+1 Where n is a positive integer from 1 to 10; the R 1 and the OR 2 The total quantity is 4, and m is a natural number from 0 to 3; the functional additives include, but are not limited to, wetting agents, leveling agents, etc.

[0042] To ensure that the dispersion of nano-titanium oxide can be evenly spread on the surface of the inorganic coating, the inorganic coating can also be a colored paint; preferably, the raw materials of the coating forming the inorganic coating include: 70-80 wt% solution; 5-10 wt% functional additives, wherein the functional additives are selected from potassium titanate, alumina, or a combination of the two; 10-20 wt% inorganic pigment; and 0.5-2.0 wt% other functional additives; the raw materials of the solution include the following components: 30-40 wt% organoalkoxysilane, 15-20 wt% organic solvent, and 25-30 wt% silica sol; wherein the organoalkoxysilane has the molecular formula R 1 m Si(OR 2 ) 4-m Indicates; the R 1 Selected from alkyl groups; the R 2 Selected from alkyl groups; the general formula of the alkyl group is C0. n H 2n+1 Where n is a positive integer from 1 to 10; the R 1 and the OR 2The total quantity is 4, and m is a natural number from 0 to 3; the above percentages are the mass percentages of each raw material in the total weight of the inorganic coating; for details, please refer to the applicant's prior related patent: publication number CN105038335B, patent name "A room temperature curing inorganic coating and its manufacturing method". Alternatively, the raw materials of the coating forming the inorganic coating of the present invention preferably include: 30-99.9% inorganic resin; 0.1-70% silicon nitride; 0-10% functional additives; 0-18% inorganic pigments; 0-2% other functional additives; the total amount of the coating is 100%; wherein, the inorganic resin is obtained by mixing and reacting an organoalkoxysilane, an organic solvent and a silica sol, extracting alcohol and adding deionized water; the mass ratio of the organoalkoxysilane, the organic solvent and the silica sol is 1-1.6:0.5-0.8:1; the organoalkoxysilane has the molecular formula R 1 m Si(OR 2 ) 4-m Indicates; the R 1 Selected from alkyl groups; the R 2 Selected from alkyl groups; the general formula of the alkyl group is C0. n H 2n+1 Where n is a positive integer from 1 to 10; the R 1 and the OR 2 The total quantity is 4, and m is a natural number from 0 to 3; the inorganic resin is an acidic cationic system; the VOC content of the inorganic resin is ≤10% by mass percentage; the functional additives are selected from at least one of potassium titanate, alumina and nano-silica; for details, please refer to the applicant's prior related patent: publication number CN112280344B, patent name "Ceramic Composite Coating, Antiviral Ceramic Composite Coating and its Preparation Method and Coating".

[0043] When the inorganic coating is still wet, the alcohol solvent contained in the inorganic coating or the alcohol solvent generated by the self-condensation of the inorganic coating can mutually wet the water and / or alcohol solvent in the nano-titanium oxide dispersion. Under the liquid fusion effect, the nano-titanium oxide particles in the dispersion are evenly spread on the surface of the inorganic coating, thereby achieving the uniform spreading of nano-titanium oxide particles on the surface of the object. As the coating dries and forms, the nano-titanium oxide particles are firmly bonded to the surface of the object by the inorganic coating. Furthermore, after drying, the nano-titanium oxide coating contains only nano-titanium oxide particles, which are located on the outermost surface of the coating. Therefore, the nano-titanium oxide particles are not embedded by any other substance, allowing them to maximize their photocatalytic effect. Moreover, since nano-titanium oxide particles can decompose organic matter under light conditions when acting as a photocatalyst, and the material binding the nano-titanium oxide particles is an inorganic coating that does not contain traditional organic substances such as emulsions or resins, the nano-titanium oxide particles do not affect the inorganic coating when they are working as a photocatalyst. In other words, the inorganic coating binding the nano-titanium oxide particles is not damaged, thus greatly extending the adhesion time of the nano-titanium oxide particles to the object surface, allowing them to exert their photocatalytic effect for a long time.

[0044] To better realize the long-lasting photocatalytic effect of nano-titanium oxide particles, the present invention preferably uses nano-titanium oxide particles with a particle size of 5-100 nm. If the particle size of nano-titanium oxide particles is less than 5 nm, they may be embedded in the inorganic coating due to their small particle size, affecting their effectiveness as a photocatalyst. If the particle size of nano-titanium oxide particles is greater than 100 nm, they may be too large to be embedded in the silicon-oxygen-silicon network structure of the inorganic coating, thereby affecting their bonding strength with the inorganic coating and causing the nano-titanium oxide particles to easily fall off, affecting their service life as a photocatalyst.

[0045] Through extensive experiments, the applicant discovered that the particle size of the nano-titanium oxide particles is more preferably 5–50 nm, 50–100 nm; more preferably 5–20 nm, 20–40 nm, 40–60 nm, 60–80 nm, 80–100 nm; and more preferably 5–10 nm, 10–15 nm, 15–20 nm, 20–25 nm, 25–30 nm, 30–35 nm, 35–40 nm, 40–45 nm, 45–50 nm, 50–55 nm, 55–60 nm, 60–65 nm, 65–70 nm, 70–75 nm, 75–80 nm, 80–85 nm, 85–90 nm, 90–95 nm, and 95–100 nm.

[0046] To better achieve the photocatalytic efficiency of the nano-titanium oxide particles, the thickness of the nano-titanium oxide coating is preferably ≤100nm. If the thickness of the nano-titanium oxide coating is too thick, the overlapping and embedding of the nano-titanium oxide particles may affect its photocatalytic efficacy. Therefore, the thickness should be as thin as possible while matching the particle size of the nano-titanium oxide particles to improve its efficiency. Through extensive experiments, the applicant has found that the thickness of the nano-titanium oxide coating is more preferably ≤80nm, ≤60nm, ≤40nm, or ≤20nm.

[0047] This invention also proposes a method for preparing a long-lasting photocatalytic coating, which includes the following steps:

[0048] S11. An inorganic coating is applied to the surface of a substrate. The inorganic coating can be a varnish as described above or a colored paint as described above. When the inorganic coating is a varnish, no solvent is added. When the inorganic coating is a colored paint, the added solvent is an alcohol solvent. Specific implementations of the inorganic coating and colored paint can be found in the applicant's prior applications: CN105038335B, entitled "A Room Temperature Curing Inorganic Coating and Its Manufacturing Method," and CN112280344B, entitled "Ceramic Composite Coating, Antiviral Ceramic Composite Coating and Its Preparation Method and Coating." Any inorganic coating formulation in these patents, provided that its solvent can wet with water to uniformly spread the nano-oxidized particles, and includes a silicon-oxygen-silicon network structure, can, on the one hand, allow the nano-oxidized particles to be physically embedded and bonded, and on the other hand, allow the titanium in the nano-oxidized particles to be chemically bonded to the silicon-oxygen-silicon network structure, thereby improving the bonding strength of the inorganic coating to the nano-oxidized particles.

[0049] S12 When the inorganic coating is in a wet state, a nano-titanium oxide coating is applied to the surface of the inorganic coating; the nano-titanium oxide coating is a water and / or alcohol dispersion of nano-titanium oxide; the present invention limits the solvent of the nano-titanium oxide coating to water and / or alcohol, and specifically limits the timing of the application of the nano-titanium oxide coating to when the inorganic coating is in a wet state. On the one hand, this is to allow the nano-oxidized particles uniformly dispersed in the nano-titanium oxide dispersion to spread evenly on the surface of the object by the combined action of the water and / or alcohol in the nano-titanium oxide coating and the alcohol solvent in the inorganic coating. On the other hand, by limiting the nano-titanium oxide coating to a dispersion of nano-titanium oxide, it is ensured that it does not contain other raw materials, so as to avoid or reduce the encapsulation of nano-oxidized particles by other raw materials and thus affect its effectiveness as a photocatalyst.

[0050] S13, through the limitations of the aforementioned two steps, the nano-titanium oxide coating and the inorganic coating are deeply integrated through physical intercalation and chemical bonding. After drying, a long-lasting photocatalytic coating can be obtained.

[0051] To facilitate better interaction between the inorganic coating and the nano-titanium oxide coating, and to promote the uniform spreading of the nano-oxidized particles, the present invention preferably states that the inorganic coating is in a wet state, meaning it is not yet surface-dry. In specific operation, the nano-titanium oxide coating can generally be applied within 10 minutes after the inorganic coating is applied, so that the nano-titanium oxide coating is applied to its surface before the inorganic coating is surface-dry. This allows for more thorough wetting of the alcohol solvent and water, and through liquid-phase fusion, the nano-oxidized particles are uniformly spread on the surface of the inorganic coating.

[0052] The present invention also proposes an application of the aforementioned long-lasting photocatalytic coating in the fields of sterilization, disinfection, or self-cleaning.

[0053] The present invention will be further described below with reference to specific embodiments, but this should not be construed as a limitation on the scope of protection of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the above description of the present invention still fall within the scope of protection of the present invention.

[0054] Unless otherwise specified, all materials and reagents mentioned below are commercially available products well known to those skilled in the art; unless otherwise specified, all methods described are methods known in the art. Unless otherwise defined, the technical or scientific terms used should have the ordinary meaning understood by those skilled in the art to which this invention pertains.

[0055] Preparation Example 1-1

[0056] This preparation example provides an inorganic coating varnish, prepared by the following method:

[0057] 1) Preparation of inorganic solution: 59 parts of methyltrimethoxysilane and 39 parts of silica sol are mixed together and stirred at 40-50°C for 5-10 minutes. The mixture of alkoxysilane and silica sol undergoes a chemical reaction and generates heat. As the reaction proceeds, it gradually changes from a turbid state to a transparent liquid, thus obtaining an inorganic solution in sol state.

[0058] 2) Stirring the mixed solution: Add 2 parts of organosilicon wetting agent and leveling agent to the inorganic solution, mix them together and stir to form an inorganic coating mixture;

[0059] 3) Extracting the coating: The above-mentioned well-stirred material is filtered through a filter screen of a certain size to extract the particles, and the coating is finally completed.

[0060] Preparation Examples 1-2

[0061] This preparation example provides an inorganic coating varnish, which is prepared in the same way as in Preparation Example 1-1. Its raw materials include the following components: 39 parts of tetraethoxysilane, 59 parts of silica sol, 2 parts of organosilicon wetting agent and leveling agent.

[0062] Preparation Examples 1-3

[0063] This preparation example provides an inorganic coating varnish, prepared using the same method as in Preparation Example 1-1. The raw materials include the following components: 20 parts methyltrimethoxysilane, 30 parts tetraethoxysilane, 49.5 parts silica sol, and 0.5 parts organosilicon wetting agent and leveling agent. Energy dispersive spectroscopy (EDS) analysis was performed on the inorganic coating varnish of this preparation example, and the results are shown in the appendix. Figure 1 As shown.

[0064] Preparation Example 2-1

[0065] This preparation example provides an inorganic coating paint, and the preparation method is as follows:

[0066] 1) Preparation of inorganic solution: Select one or a mixture of two organosilicones, namely methyltrimethoxysilane or tetraethoxysilane, and use 28 parts of organosilicon. In this preparation example, methyltrimethoxysilane is used. Mix 14 parts of ethanol and 28 parts of silica sol together and stir at 40-50°C for 5-10 minutes. The mixture of alkoxysilane and silica sol will undergo a chemical reaction and generate heat. As the reaction proceeds, it will gradually change from a turbid state to a transparent liquid, thus obtaining an inorganic solution in sol state.

[0067] 2) Preparation of inorganic resin: The above inorganic solution is vacuumed at 40-50°C for 5 minutes, while deionized water is added to replenish the amount of solvent separated by the alcohol extraction, to obtain inorganic resin; the inorganic resin has a VOC content of 8.7% and a solid content of 28%.

[0068] 3) Stirring the mixed solution: The inorganic resin and other raw materials are mixed together and stirred to form an inorganic ceramic mixture; by mass percentage, the inorganic ceramic mixture includes: 70% inorganic resin, 8% silicon nitride, 2% of a mixture of one or two of potassium titanate, alumina or nano-silica, in this preparation example, potassium titanate 1% and alumina 1%; titanium dioxide 18%, rare earth mineral powder 2%; the silicon nitride has a particle size of 1μm to 3μm; the particle size of the other added powders is less than 800nm;

[0069] 4) Homogenization: The inorganic ceramic mixture is placed in a homogenizer and stirred at high speed for 0.1 to 2 hours to homogenize the particles;

[0070] 5) Extracting the coating: The above-mentioned well-stirred material is filtered through a filter screen of a certain size to extract the particles, and the coating is finally completed.

[0071] Preparation Example 2-2

[0072] This preparation example provides an inorganic coating, which is prepared by the same method as in Preparation Example 2-1, and its raw materials include the following components:

[0073] 85% inorganic resin; the raw materials of the inorganic resin include the following components: 40.8 parts tetraethoxysilane, 18.7 parts ethanol, and 25.5 parts silica sol; the silica particles in the silica sol have a particle size of 10-50 nm; the VOC content of the inorganic resin is 9.6%, and the solid content is 25%.

[0074] 5% silicon nitride; the silicon nitride particle size is 1μm to 3μm;

[0075] Potassium titanate 5%, nano-silica 1%, alumina 4%; the particle size of the other added powders is less than 800nm.

[0076] Preparation Examples 2-3

[0077] This preparation example provides an inorganic coating, which is prepared by the same method as in Preparation Example 2-1, and its raw materials include the following components:

[0078] 80% inorganic resin; the raw materials of the inorganic resin include the following components: 26.6 parts tetraethoxysilane and 11.4 parts methyltrimethoxysilane, 18 parts ethanol, and 24 parts silica sol; the silica particles in the silica sol have a particle size of 10-50 nm; the VOC content of the inorganic resin is 7.3%, and the solid content is 30%.

[0079] 13% silicon nitride; the silicon nitride particle size is 0.5μm to 3μm;

[0080] The composition includes 3% alumina, 1% nano-silica, 2% potassium titanate, and 1% rare earth mineral powder; the particle size of the other added powders is less than 800 nm.

[0081] Preparation Examples 2-4

[0082] This preparation example provides an inorganic coating, which is prepared using the same method as in Preparation Example 2-1, and its raw materials include the following components:

[0083] 99.9% inorganic resin; the raw materials of the inorganic resin include the following components: 43.9 parts tetraethoxysilane, 21 parts ethanol, and 35 parts silica sol; the silica particles in the silica sol have a particle size of 10-50 nm; the VOC content of the inorganic resin is 7.0%, and the solid content is 32%.

[0084] 0.1% silicon nitride; the silicon nitride particle size is 100-200 nm.

[0085] Preparation Examples 2-5

[0086] This preparation example provides an inorganic coating, which is prepared using the same method as in Preparation Example 2-1, and its raw materials include the following components:

[0087] 50 wt% inorganic resin; the raw materials of the inorganic resin include the following components: 12 parts methyltriethoxysilane and 12 parts tetraethoxysilane, 11 parts ethanol, and 15 parts silica sol; the silica particles in the silica sol have a particle size of 10-50 nm; the VOC content of the inorganic resin is 8.4%, and the solid content is 29%.

[0088] 50% silicon nitride; the silicon nitride particle size is 2μm to 6μm.

[0089] Preparation Examples 2-6

[0090] This preparation example provides an inorganic coating, which is prepared using the same method as in Preparation Example 2-1, and its raw materials include the following components:

[0091] 30 wt% inorganic resin; the raw materials of the inorganic resin include the following components: 13 parts methyltriethoxysilane, 7 parts ethanol, and 10 parts silica sol; the silica particles in the silica sol have a particle size of 10-50 nm; the VOC content of the inorganic resin is 9.3%, and the solid content is 26%.

[0092] 70% silicon nitride; the silicon nitride particle size is 2μm to 6μm.

[0093] Preparation Example 3-1

[0094] This preparation example provides an inorganic coating paint, the preparation method of which is as follows:

[0095] 1) In the stage of preparing the inorganic solution according to this invention, 30 wt% of an organosilane (selected from methyltrimethoxysilane or tetraethoxysilane or a mixture thereof), 15 wt% of ethanol, and 30 wt% of silica sol (abbreviated as silica gel) are mixed together and stirred at 40-50°C for about 5-10 minutes. The mixture of alkoxysilane and silica sol undergoes a chemical reaction, resulting in heat generation. As the reaction proceeds, the solution gradually changes from a turbid state to a transparent liquid. At this point, to adjust the viscosity and reaction rate of the solution, one of methanol, ethanol, isopropanol, or a mixture thereof is added. Through these steps, a sol-like inorganic solution is prepared.

[0096] 2) In the mixing stage of this invention, one of the inorganic solution, potassium titanate or alumina produced in the previous stage is selected as a functional additive (9wt%), 15wt% titanium dioxide pigment powder and 1wt% other functional additives are mixed together and stirred to form an inorganic coating mixture.

[0097] 3) In the homogenization stage, put the stirred material into a homogenizer and stir at high speed for 1-2 hours to homogenize the particles.

[0098] 4) In the coating extraction stage, the homogenized material from the above stage is filtered through a filter screen of a certain size to extract particles, and the coating is finally completed.

[0099] Preparation Example 3-2

[0100] This preparation example provides an inorganic coating, which is prepared using the same method as in Preparation Example 3-1. The raw materials for the inorganic coating include the following components:

[0101] 70 wt% inorganic solution; the raw materials of the inorganic solution include the following components: 30 wt% tetraethoxysilane, 15 wt% ethanol, and 25 wt% silica sol.

[0102] 10 wt% of functional additives, wherein the functional additives are a composition of potassium titanate and alumina, wherein the content of potassium titanate is 3%;

[0103] 19.5 wt% inorganic pigments;

[0104] 0.5 wt% of other functional additives; said other functional additives are tourmaline.

[0105] The percentages mentioned above represent the weight percentage of each raw material in the total weight of the inorganic coating.

[0106] Preparation Example 3-3

[0107] This preparation example provides an inorganic coating, which is prepared using the same method as in Preparation Example 3-1. The raw materials for the inorganic coating include the following components:

[0108] 80 wt% inorganic solution; the raw materials of the inorganic solution include the following components: 40 wt% tetraethoxysilane and methyltrimethoxysilane composition, the weight ratio of tetraethoxysilane and methyltrimethoxysilane is 1:1, 15 wt% ethanol, and 25 wt% silica sol.

[0109] 5 wt% of functional additives, wherein the functional additives are a composition of potassium titanate and alumina, wherein the content of potassium titanate is 4%;

[0110] 13 wt% inorganic pigments;

[0111] 2 wt% of other functional additives; the other functional additives are tourmaline.

[0112] The percentages mentioned above represent the weight percentage of each raw material in the total weight of the inorganic coating.

[0113] Preparation Examples 3-4

[0114] This preparation example provides an inorganic coating, which is prepared using the same method as in Preparation Example 3-1. The raw materials for the inorganic coating include the following components:

[0115] An 80 wt% inorganic solution; the raw materials of the inorganic solution include the following components: 30 wt% methyltrimethoxysilane, 20 wt% ethanol, and 30 wt% silica sol.

[0116] 6 wt% of functional additives, wherein the functional additives are a composition of potassium titanate and alumina, wherein the content of potassium titanate is 5%;

[0117] 13 wt% inorganic pigments;

[0118] 1 wt% of other functional additives; the other functional additives are rare earth raw ores.

[0119] The percentages mentioned above represent the weight percentage of each raw material in the total weight of the inorganic coating.

[0120] Preparation Examples 3-5

[0121] This preparation example provides an inorganic coating, which is prepared using the same method as in Preparation Example 3-1. The raw materials for the inorganic coating include the following components:

[0122] 74.5 wt% inorganic solution; the raw materials of the inorganic solution include the following components: 30 wt% methyltriethoxysilane, 15 wt% ethanol, and 29.5 wt% silica sol;

[0123] 5 wt% of functional additives, wherein the functional additives are potassium titanate;

[0124] 20wt% inorganic pigments;

[0125] 0.5 wt% of other functional additives; the other functional additives are rare earth raw ores.

[0126] The percentages mentioned above represent the weight percentage of each raw material in the total weight of the inorganic coating.

[0127] Preparation Examples 3-6

[0128] This preparation example provides an inorganic coating, which is prepared using the same method as in Preparation Example 3-1. The raw materials for the inorganic coating include the following components:

[0129] 77 wt% inorganic solution; the raw materials of the inorganic solution include the following components: 35 wt% alkoxysilane, 15 wt% ethanol, and 27 wt% silica sol.

[0130] 7 wt% of functional additives, wherein the functional additives are potassium titanate;

[0131] 15wt% inorganic pigments;

[0132] 1 wt% of other functional additives; the other functional additives are a combination of tourmaline and rare earth minerals in a weight ratio of 1:1.

[0133] The percentages mentioned above represent the weight percentage of each raw material in the total weight of the inorganic coating.

[0134] The alkoxysilane has the molecular formula R1mSi(OR2). 4-m This indicates that R2 is phenyl and m is 0.

[0135] Preparation Example 4-1

[0136] This preparation example provides a nano-titanium oxide dispersion. Under stirring conditions, a dispersant is added to deionized water, and then nano-titanium oxide particles are added and stirred evenly. The nano-titanium oxide dispersion includes the following components: nano-titanium oxide, 0.5%, with a particle size of 30 nm; deionized water, 98.5%; and dispersant, 1%. The above percentages are the weight percentages of each raw material in the total weight of the nano-titanium oxide dispersion.

[0137] Preparation Example 4-2

[0138] This preparation example provides a nano-titanium oxide dispersion, which is prepared by the same method as in Preparation Example 4-1. The nano-titanium oxide dispersion includes the following components: nano-titanium oxide, 1%, with a particle size of 20 nm; deionized water, 99%; and dispersant, 1%. The above percentages are the weight percentages of each raw material in the total weight of the nano-titanium oxide aqueous dispersion.

[0139] Preparation Example 4-3

[0140] This preparation example provides a nano-titanium oxide dispersion, which is prepared by the same method as in Preparation Example 4-1. The nano-titanium oxide dispersion includes the following components: nano-titanium oxide, 5%, with a particle size of 10 nm; ethanol, 85%; dispersant, 10%; the above percentages are the weight percentages of each raw material in the total weight of the nano-titanium oxide aqueous dispersion.

[0141] Examples 1-15

[0142] The long-lasting photocatalytic coating was prepared according to the material configuration and process in the table below. First, an inorganic coating was applied to the surface of the substrate material. Then, a nano-titanium oxide coating was applied to the surface of the inorganic coating within 10 minutes. After drying, the long-lasting photocatalytic coating was obtained.

[0143] The performance of the long-lasting photocatalytic coating in decomposing organic matter was tested. The specific procedure was as follows: a saturated ethanol solution of methyl red (analytical grade) was prepared. The solution was then applied lightly to the test panel with a brush, and cured in the dark for 4 hours. The cured test panel was then placed in a test chamber for ultraviolet light irradiation testing. The light source was UVA-340, and the irradiance was 0.68 W / m². 2The blackboard thermometer temperature was 60±3℃. After 300 hours of ultraviolet light irradiation, the test plate was removed and compared with a blank test plate without methyl red saturated ethanol solution. The color difference value was determined according to 4.2.1 of GB / T1766.

[0144] The adhesion performance of the long-lasting photocatalytic coating after aging was tested. The specific procedure was as follows: Test samples were prepared using the test panels from the above-mentioned organic matter decomposition test and blank test panels. The test was conducted according to the cross-cut test for paint and varnish coatings in GB / T 9286. The sample was placed on a hard, flat surface to avoid deformation. A knife was used perpendicular to the sample surface, applying uniform force to the cutting blade. Using a suitable spacing guide device, six parallel horizontal cutting lines and six parallel vertical cutting lines were formed on the coating at a uniform cutting rate. All cuts should penetrate to the substrate surface. A soft brush was used to gently sweep backwards and then forwards several times along each diagonal of the grid pattern. The center point of 3M tape was placed above the grid, parallel to one set of cutting lines. The tape was then pressed flat above the grid area with the fingers, ensuring the tape length exceeded the grid by at least 20mm. Within 5 minutes of applying the tape, hold one end of the tape suspended in the air and peel it off smoothly and steadily over 0.5 to 1.0 seconds at an angle of approximately 60°. Inspect the coated area under good lighting conditions.

[0145] In Examples 1-15 above, both the inorganic coating and the nano-titanium oxide dispersion were applied using a spraying process; the specific process parameters and test results are shown in Table 2 below.

[0146] Table 2

[0147]

[0148] As can be seen from the above test data, after ultraviolet light irradiation, the color difference ΔE between the test panel coated with methyl red and the blank test panel without methyl red is less than 3.0. That is, the long-lasting photocatalytic coating of the present invention has good performance in decomposing organic matter and high efficiency in decomposing organic matter.

[0149] The test data above also show that after 300 hours of ultraviolet light irradiation, the coating on the methyl red-coated test plate remained unchanged, the nano-oxidized particles remained firmly attached, and there was no reduction in adhesion.

[0150] The technical features in the claims and / or specification of this invention can be combined, and the combination is not limited to the combinations obtained through reference in the claims. Technical solutions obtained by combining the technical features in the claims and / or specification are also within the scope of protection of this invention.

[0151] The above description is merely a preferred preparation example of the present invention and is not intended to limit the present invention in any way. Any simple modifications, equivalent changes and alterations made to the above preparation examples based on the technical essence of the present invention shall still fall within the scope of the technical solution of the present invention.

Claims

1. A long-lasting photocatalytic coating, characterized in that, It includes: Base; An inorganic coating is applied to the surface of the substrate; The inorganic coating comprises a silicon oxide network structure formed by the self-condensation reaction of an organoalkoxysilane and a silica sol. A nano-titanium oxide coating is disposed on the surface of the inorganic coating; The method for preparing the long-lasting photocatalytic coating includes the following steps: S11 applies inorganic coating to the surface of the substrate; S12 When the inorganic coating is in a wet state, a nano-titanium oxide coating is applied to the surface of the inorganic coating; the nano-titanium oxide coating is an aqueous and / or alcoholic dispersion of nano-titanium oxide, and does not contain a binder; S13 nano-titanium oxide coating is fused with inorganic coating and dried to obtain a long-lasting photocatalytic coating.

2. The long-lasting photocatalytic coating according to claim 1, characterized in that, The thickness of the nano-titanium oxide coating is ≤100nm; the particle size of the nano-titanium oxide particles in the nano-titanium oxide coating is 5~100nm.

3. The long-lasting photocatalytic coating according to claim 2, characterized in that, The thickness of the nano-titanium oxide coating is ≤50nm; the particle size of the nano-titanium oxide particles in the nano-titanium oxide coating is 5~50nm.

4. The long-lasting photocatalytic coating according to claim 1, characterized in that, The raw materials for forming the inorganic coating include: 39-59 wt% organoalkoxysilane, 39-59 wt% silica sol, and 0.5-2 wt% functional additives; the total amount of the organoalkoxysilane, silica sol, and functional additives is 100 wt%; the organoalkoxysilane has the molecular formula R 1 m Si(OR 2 ) 4-m Indicates; the R 1 Selected from alkyl groups; the R 2 Selected from alkyl groups; the general formula of the alkyl group is C0. n H 2n+1 Where n is a positive integer from 1 to 10; the R 1 and the OR 2 The total number is 4, and m is a natural number from 0 to 3.

5. The long-lasting photocatalytic coating according to claim 1, characterized in that, The raw materials for forming the inorganic coating include: 70-80 wt% solution; 5-10 wt% functional additives selected from potassium titanate, alumina, or a combination thereof; 10-20 wt% inorganic pigment; and 0.5-2.0 wt% other functional additives. The solution comprises: 30-40 wt% organoalkoxysilane, 15-20 wt% organic solvent, and 25-30 wt% silica sol. The organoalkoxysilane has the molecular formula R... 1 m Si(OR 2 ) 4-m Indicates; the R 1 Selected from alkyl groups; the R 2 Selected from alkyl groups; the general formula of the alkyl group is C0. n H 2n+1 Where n is a positive integer from 1 to 10; the R 1 and the OR 2 The total quantity is 4, and m is a natural number from 0 to 3; the above percentages are the mass percentages of each raw material in the total weight of the inorganic coating.

6. The long-lasting photocatalytic coating according to claim 1, characterized in that, The raw materials for forming the inorganic coating include: 30-99.9% inorganic resin; 0.1-70% silicon nitride; 0-10% functional additives; 0-18% inorganic pigments; and 0-2% other functional additives; the total amount of the coating is 100%; wherein the inorganic resin is obtained by mixing and reacting an organoalkoxysilane, an organic solvent, and a silica sol, removing alcohol, and adding deionized water; the mass ratio of the organoalkoxysilane, organic solvent, and silica sol is 1-1.6:0.5-0.8:1; the organoalkoxysilane has the molecular formula R 1 m Si(OR 2 ) 4-m Indicates; the R 1 Selected from alkyl groups; the R 2 Selected from alkyl groups; the general formula of the alkyl group is C0. n H 2n+1 Where n is a positive integer from 1 to 10; the R 1 and the OR 2 The total quantity is 4, and m is a natural number from 0 to 3; the inorganic resin is an acidic cationic system; the VOC content of the inorganic resin is ≤10% by mass percentage; the functional additives are selected from at least one of potassium titanate, alumina and nano-silica.

7. A method for preparing a long-lasting photocatalytic coating according to any one of claims 1 to 6, characterized in that, It includes the following steps: S11 applies inorganic coating to the surface of the substrate; S12 When the inorganic coating is in a wet state, a nano-titanium oxide coating is applied to the surface of the inorganic coating; the nano-titanium oxide coating is an aqueous and / or alcoholic dispersion of nano-titanium oxide. S13 nano-titanium oxide coating is fused with inorganic coating and dried to obtain a long-lasting photocatalytic coating.

8. The preparation method according to claim 7, characterized in that, The inorganic coating being in a wet state refers to the state of the inorganic coating before it has dried to the touch.

9. The application of a long-lasting photocatalytic coating according to any one of claims 1 to 6 in the fields of sterilization, disinfection, or self-cleaning.

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