Coating material, filter screen and preparation method of filter screen

Abstract

The invention relates to a coating material, a filter screen and a preparation method of the filter screen. The coating material is prepared from the following components in parts by mass: 100 parts of porcelain liquid, 0.01 to 0.5 part of alkali-resistant penetrant and 0.3 to 2 parts of alkyl siloxane, wherein the porcelainizing liquid comprises alkaline silica sol, the alkaline silica sol comprises one or two of branched silica sol and bead-like silica sol, and in the porcelainizing liquid, the silica nanoparticles account for 2%-8% of the mass of the porcelainizing liquid; the alkali-resistant penetrant is selected from one or more of a nonionic penetrant and an anionic penetrant, and the HLB (hydrophile-lipophile balance) value of the alkali-resistant penetrant is 7-16. The coating material is applied to the filter screen, and the prepared coating has good hydrophobicity and can not easily block meshes of the filter screen while having good adhesive force.

Description

Technical Field

[0001] The present application relates to the field of filter screens, and in particular to a coating material, a filter screen, and a preparation method thereof. Background Art

[0002] The pre-filter is the first coarse filtration device for household water. Its filter can filter a small amount of fine mud, rust or other particles in municipal tap water. However, the current filter still has the following problems: after the fine particles in the tap water are intercepted by the filter, they adhere to the filter and even clog the filter. Even if backwashing is turned on, it is difficult to effectively discharge the pollutants, which leads to a decrease in the flow rate of household water and easy damage to the filter. Therefore, the filter needs to be disassembled, cleaned or replaced in time. The disassembly, cleaning and replacement of the filter requires professional personnel, which increases the cost. In order to solve the above problems, the researchers treated the surface of the filter to form a hydrophobic coating on the surface of the filter, and used the hydrophobicity of the coating to prevent fine particles from adhering. However, traditional hydrophobic coatings still have poor adhesion to the filter substrate and are prone to clogging the filter mesh. Summary of the Invention

[0003] Based on this, some embodiments of the present application provide a coating material having good hydrophobicity, which makes it difficult for fine particles to adhere, and the prepared coating can have good adhesion to the filter mesh substrate while not easily clogging the filter mesh.

[0004] In addition, some other embodiments of the present application also provide a filter screen and a method for preparing the same.

[0005] A coating material, comprising, by weight: 100 parts of a porcelainizing liquid, 0.01 to 0.5 parts of an alkali-resistant penetrant, and 0.3 to 2 parts of an alkyl siloxane;

[0006] The porcelainizing liquid comprises alkaline silica sol, and the alkaline silica sol comprises one or both of branched silica sol and beaded silica sol. In the porcelainizing liquid, the mass percentage of silicon dioxide nanoparticles in the porcelainizing liquid is 2% to 8%;

[0007] The alkali-resistant penetrant is selected from one or more of a nonionic penetrant and an anionic penetrant, and has an HLB value of 7-16.

[0008] Optionally, the ceramic liquid satisfies one or more of the following conditions:

[0009] (1) The pH of the porcelainizing solution is 10-13. Optionally, the pH of the porcelainizing solution is 10-12.

[0010] (2) The average particle size of the silica nanoparticles is 2 nm to 50 nm; optionally, the average particle size of the silica nanoparticles is 2 nm to 15 nm;

[0011] (3) The porcelainizing solution also includes a corrosion inhibitor.

[0012] Optionally, the alkali-resistant penetrant is a non-ionic penetrant.

[0013] Optionally, the alkali-resistant penetrant includes one or more of alkyl polyglucoside, fatty alcohol polyoxyethylene polyoxypropylene ether, nonylphenol polyoxyethylene ether, perfluoroalkyl ethoxy ether alcohol, perfluoroalkyl polyoxyethylene ether and perfluoropolyether polyoxyethylene ether.

[0014] Optionally, the alkali-resistant penetrant includes one or more of perfluoroalkyl ethoxy ether alcohol, perfluoroalkyl polyoxyethylene ether and perfluoropolyether polyoxyethylene ether, and the mass fraction of the alkali-resistant penetrant is 0.01 part to 0.1 part.

[0015] Optionally, the general structural formula of the alkylsiloxane is Si(OR 1 )3R 2 , each R 1 Each includes one of C1~C3 alkyl and C2~C3 alkanoyl, R 2 Including C1~C 12 Alkyl and fluorine-substituted C1~C 12 One of the alkyl groups.

[0016] Optionally, R 2 Including C6~C 12 Alkyl and fluorine-substituted C6~C 12 One of the alkyl groups.

[0017] Optionally, the alkylsiloxane includes one or more of heptadecafluorodecyltrimethoxysilane, tridecafluorooctyltrimethoxysilane, nonafluorohexyltrimethoxysilane and dodecyltrimethoxysilane.

[0018] Optionally, the coating material further comprises: 0.2 to 1 part of an adhesion promoter and 1 to 8 parts of a fluoropolymer water-based dispersion.

[0019] Optionally, the adhesion promoter includes a phosphate ester promoter.

[0020] Optionally, the adhesion promoter includes one or more of 2-hydroxyethyl methacrylate phosphate, alkyl acrylate phosphate, di(methacryloyloxyethyl) hydrogen phosphate and polyethylene glycol methacrylate phosphate.

[0021] Optionally, the adhesion promoter comprises 2-hydroxyethyl methacrylate phosphate.

[0022] Optionally, the fluoropolymer water-based dispersion includes a fluoropolymer and a nonionic surfactant, the mass percentage of the fluoropolymer in the fluoropolymer water-based dispersion is 40% to 60%, and the mass percentage of the nonionic surfactant in the fluoropolymer water-based dispersion is 4% to 6%.

[0023] Optionally, the fluoropolymer water-based dispersion includes one of a polytetrafluoroethylene dispersion, a perfluoroalkoxy resin dispersion and a fluorinated ethylene propylene copolymer dispersion.

[0024] Optionally, the aqueous fluoropolymer dispersion comprises a fluorinated ethylene propylene copolymer dispersion.

[0025] A filter screen comprises a filter screen substrate and a coating arranged on the surface of the filter screen substrate, wherein the coating is made of the above-mentioned coating material.

[0026] Optionally, the filter screen substrate is made of one or more materials selected from the group consisting of stainless steel, nylon, polyethylene and polypropylene.

[0027] Optionally, the average pore size of the filter screen substrate is 40 μm to 100 μm.

[0028] Optionally, the coating has a thickness of 1 μm to 10 μm.

[0029] Optionally, the coating has a thickness of 1 μm to 5 μm.

[0030] Optionally, the coating has a thickness of 1 μm to 2 μm.

[0031] A method for preparing a filter screen comprises the following steps:

[0032] A coating material is applied to the surface of a filter screen substrate and solidified to form a coating on the surface of the filter screen substrate to prepare a filter screen. The coating material is as described above.

[0033] Optionally, the step of applying a coating material on the surface of the filter screen substrate includes: soaking the filter screen substrate in the coating material for 60 seconds to 120 seconds, taking it out and drying the surface for 5 minutes to 10 minutes.

[0034] Optionally, the curing step includes: heating at 60°C to 90°C for 10 minutes to 20 minutes, raising the temperature to 150°C to 210°C and heating for 20 minutes to 40 minutes.

[0035] Optionally, before the step of applying the coating material on the surface of the filter screen substrate, the method further comprises performing a surface hydroxylation treatment on the filter screen substrate.

[0036] Optionally, the surface of the filter screen substrate is hydroxylated by plasma treatment.

[0037] Optionally, the step of preparing the coating material includes:

[0038] Mixing and stirring the alkali-resistant penetrant and the porcelainizing liquid;

[0039] The obtained mixture is mixed with the alkylsiloxane and stirred to prepare the coating material.

[0040] The present application has found that the traditional hydrophobic coating is easy to clog the filter mesh, which may be due to its thick thickness. When the thickness is thin, the coating has poor adhesion to the filter substrate and is easy to fall off, resulting in a decrease in hydrophobicity. Therefore, the traditional hydrophobic coating still has the problem of poor adhesion to the filter substrate and easy clogging of the filter mesh. Based on this, the present application provides a coating material, including a certain ratio of porcelain liquid, an alkali-resistant penetrant and an alkyl siloxane. By optimizing each component, the coating material has a good hydrophobic effect. For example, when applied to a filter, the filter can effectively resist the attachment of fine sediment, rust or other particles. Even if attached, the attachments can be effectively removed after turning on the backwash function of the pre-filter. The prepared hydrophobic coating can have good adhesion at a thinner thickness and is not easy to clog the filter mesh, effectively reducing the maintenance costs such as disassembly, cleaning and replacement of the filter, and improving the service life of the product.

[0041] Specifically, the alkylsiloxane in the coating material can be hydrolyzed in an alkaline silica sol system to produce silanols. The surface hydroxyl groups of the silanols condense with the surface Si-OH groups of the silica sol, thereby transferring the hydrophobic alkyl groups in the alkylsiloxane and bonding them to the surface of the silica sol. They can also further undergo polycondensation on the surface of the silica nanoparticles to form a dense film. The remaining Si-OH groups in the silica sol can self-condense into new Si-O-Si links, forming a surface network structure of silica that is cross-linked, so that the prepared coating has excellent hydrophobic properties. The alkaline silica sol selected in a branched and / or beaded form will cross-overlap with each other during the drying and film-forming process, and has good film-forming properties and adhesion to the stainless steel filter. The alkali-resistant penetrant can improve the wettability of the filter, reduce the surface tension, and better disperse the silica nanoparticles in the silica sol on the filter surface, thereby improving the wettability and adhesion. Therefore, the components in the above coating material work together and, when applied to the filter, have good hydrophobicity, making it difficult for fine particles to adhere, and the prepared coating can have good adhesion while not easily clogging the filter mesh. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0043] Figure 1 A schematic diagram of a process flow of a method for preparing a filter screen according to some embodiments of the present application. DETAILED DESCRIPTION

[0044] To facilitate understanding of the present application, the present application will be described more fully below in conjunction with the specific embodiments. Preferred embodiments of the present application are provided in the specific embodiments. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present application more thorough and comprehensive.

[0045] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application pertains. The terms used herein in the specification of this application are for the purpose of describing specific embodiments only and are not intended to limit this application. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0046] Unless otherwise specified or incompatible therewith, terms and phrases used in this application shall have the following meanings:

[0047] In this application, the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of technical features indicated. Therefore, a feature specified as "first" or "second" may explicitly or implicitly include at least one of the features.

[0048] In the description of the present application, “a plurality of” means at least two, for example, two, three, etc., unless otherwise clearly and specifically defined.

[0049] In this application, "one or several" refers to any one, any two, or any two or more of the listed items. Among them, "several" refers to any two or any two or more.

[0050] In this application, the percentage concentration involved, unless otherwise specified, refers to the final concentration. The final concentration refers to the percentage of the added component in the system after the addition of the component.

[0051] In this application, the terms "further," "further," "particularly," "for example," "such as," "example," and "for example" are used for descriptive purposes to indicate that the preceding and following technical solutions are related in terms of their coverage, but should not be construed as limiting the preceding technical solution or the scope of protection of this document. In this document, unless otherwise specified, "A (such as B)" means that B is a non-limiting example of A, and it is understood that A is not limited to B.

[0052] In this application, "optionally", "optional", and "optional" mean optional, that is, any one of the two parallel options of "with" or "without". If multiple "optional" appear in a technical solution, unless otherwise specified and there is no contradiction or mutual restriction, each "optional" is independent. In this application, descriptions such as "optionally contain" and "optionally include" mean "containing or not containing". "Optional component X" means the presence or absence of component X, or means containing or not containing component X.

[0053] When a numerical range is disclosed in this application, the range is considered continuous and includes the minimum and maximum values ​​of the range, as well as every value between such minimum and maximum values. Further, when a range refers to an integer, every integer between the minimum and maximum values ​​of the range is included. In addition, when multiple ranges are provided to describe a feature or characteristic, the ranges can be combined. In other words, unless otherwise indicated, all ranges disclosed in this application should be understood to include any and all subranges subsumed therein.

[0054] In this application, the technical features described in an open manner include closed technical solutions composed of the listed features, and also include open technical solutions containing the listed features.

[0055] The terms "including," "having," and any variations thereof in the embodiments of the present application are intended to cover non-exclusive inclusions. For example, a process, method, system, product, or apparatus comprising a series of steps or units is not limited to the listed steps or units but may optionally include steps or units not listed, or may optionally include other steps or components inherent to the process, method, product, or apparatus.

[0056] References to "embodiments" in this application mean that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described in this application may be combined with other embodiments.

[0057] In the flowchart of the present application, although the various steps are displayed in sequence as indicated by the arrows, these steps are not necessarily performed in the order indicated by the arrows. Unless otherwise specified in the text, there is no strict order restriction for the execution of these steps, and they can be performed in other orders. Moreover, at least part of the steps in the figure may include multiple sub-steps or multiple stages. These sub-steps or stages are not necessarily performed at the same time, but can be performed at different times. Their execution order is not necessarily sequential, but can be performed in turn or alternately with other steps or at least part of other sub-steps or stages.

[0058] A first aspect of the present application provides a coating material comprising, by mass, 100 parts of a porcelainizing liquid, 0.01 to 0.5 parts of an alkali-resistant penetrant, and 0.3 to 2 parts of an alkyl siloxane;

[0059] The porcelainizing liquid includes alkaline silica sol, which includes one or both of branched silica sol and beaded silica sol. In the porcelainizing liquid, the mass percentage of silicon dioxide nanoparticles in the porcelainizing liquid is 2% to 8%.

[0060] The alkali-resistant penetrant is selected from one or more of a non-ionic penetrant and an anionic penetrant, and the HLB value is 7-16.

[0061] The present application provides a coating material, including a certain ratio of porcelain liquid, alkali-resistant penetrant and alkyl siloxane. By optimizing each component, the coating material has a good hydrophobic effect. When applied to a filter net, the filter net can effectively resist the attachment of fine mud, rust or other particles. Even if attached, the attachments can be effectively removed after turning on the backwash function of the pre-filter. The prepared hydrophobic coating can have good adhesion at a thin thickness and is not easy to clog the filter mesh, so that the filter net has good water flow and filtering capacity, effectively reducing the maintenance costs such as disassembly, cleaning and replacement of the filter net, and improving the service life of the product.

[0062] In some embodiments of the present application, the mass percentage of silica nanoparticles in the porcelain liquid is 2% to 8%. If the mass percentage of silica nanoparticles in the porcelain liquid is too low, the rigidity of the coating prepared by the above-mentioned coating material is too low and the wear resistance is poor. If the mass percentage of silica nanoparticles in the porcelain liquid is too high, it will cause the filter mesh to be clogged when used in the filter, affecting the water flow and filtering effect of the pre-filter. In one example, the mass percentage of silica nanoparticles in the porcelain liquid can be, but is not limited to, 2%, 3%, 4%, 5%, 6%, 7%, 8%, or a range consisting of any two of these values.

[0063] In some embodiments of the present application, compared with alkylsiloxane and alkali-resistant penetrant, if the content of the porcelain liquid is too high, there will be more surface hydroxyl groups, making the hydroxyl groups far exceed the hydrophobic groups, which will greatly reduce the surface hydrophobic effect.

[0064] In some embodiments, the alkaline silica sol comprises one or both of branched and beaded silica sols. Branched refers to silica (SiO2) nanoparticles forming a branched structure through chemical bonds or physical interactions, while beaded refers to silica nanoparticles linked end-to-end to form a linear or chain-like structure similar to a "bead string." This can be determined by observing the morphology of the silica nanoparticles under a microscope. Branched and / or beaded silica sols interlock and overlap during the drying and film-forming process, resulting in significantly better film-forming properties and metal adhesion than conventional spherical silica sols or acidic or neutral silica sols. Furthermore, the use of a relatively pure organic silica sol can impart greater rigidity to the hydrophobic coating, improving wear resistance and service life.

[0065] In some embodiments, the ceramic coating solution comprises an alkaline silica sol containing 2% to 8% by mass of silica nanoparticles, wherein the alkaline silica sol comprises one or both of branched silica sol and beaded silica sol. In other embodiments, the ceramic coating solution further comprises an additive, such as, but not limited to, a corrosion inhibitor. The addition of a corrosion inhibitor to the ceramic coating solution can improve the corrosion resistance of the resulting coating. The specific amount of the corrosion inhibitor used is not particularly limited and may be any commonly used agent in the art, and will not be further described here.

[0066] In some embodiments, the average particle size of the silica nanoparticles is 2 nm to 50 nm. For example, the average particle size of the silica nanoparticles can be, but is not limited to, 2 nm, 3 nm, 5 nm, 6 nm, 7 nm, 8 nm, 9 nm, 10 nm, 11 nm, 12 nm, 13 nm, 14 nm, 15 nm, 16 nm, 20 nm, 25 nm, 30 nm, 40 nm, 45 nm, 50 nm, or a range consisting of any two of these values.

[0067] In some embodiments, the pH value of the ceramic liquid is 10 to 13. For example, the pH value of the ceramic liquid can be, but is not limited to, 10, 10.5, 11, 11.5, 12, 12.5, 13, or a range consisting of any two of these values.

[0068] Alkali-resistant penetrants can improve the wettability of the filter substrate, reduce surface tension, and better disperse the silica nanoparticles in the silica sol on the surface of the filter substrate, improving wettability and adhesion. Without the addition of alkali-resistant penetrants, the filter will have poor or no hydrophobic properties in some areas.

[0069] In some embodiments, the alkali-resistant penetrant is selected from one or more of a nonionic penetrant and an anionic penetrant. Using such an alkali-resistant penetrant facilitates better dispersion of the silica nanoparticles in the silica sol on the surface of the filter substrate, improving wettability and adhesion while also enhancing system stability and preventing instabilities such as flocculation and precipitation.

[0070] In some embodiments, the alkali-resistant penetrant is a nonionic penetrant. Excessive addition of anionic penetrants can result in excessively high ionic strength, which can have adverse effects. Furthermore, the highly charged environment of the alkaline silica sol interacts with the anionic penetrant, resulting in wetting barriers. Therefore, in some embodiments of the present application, the alkali-resistant penetrant is preferably a nonionic penetrant.

[0071] In some embodiments, the alkali-resistant penetrant includes one or more of alkyl polyglucoside, fatty alcohol polyoxyethylene polyoxypropylene ether, nonylphenol polyoxyethylene ether, perfluoroalkyl ethoxy ether alcohol, perfluoroalkyl polyoxyethylene ether, and perfluoropolyether polyoxyethylene ether.

[0072] Specifically, the HLB value of alkyl polyglucoside is 10-14. The HLB value of fatty alcohol polyoxyethylene polyoxypropylene ether is 8-15. The HLB value of nonylphenol polyoxyethylene ether is 13.3. The HLB value of perfluoroalkyl ethoxy ether alcohol is 8-12. The HLB value of perfluoroalkyl polyoxyethylene ether is 7-9. The HLB value of perfluoropolyether polyoxyethylene ether is 10-15.

[0073] In one example, the perfluoroalkyl polyoxyethylene ether can be Chemours FS-65, the perfluoropolyether polyoxyethylene ether can be Chemours FS-3100, and the perfluoroalkyl ethoxylate alcohol can be Chemours FS-200.

[0074] Specifically, the alkyl polyglucoside may be, but is not limited to, a C6~C8 alkyl polyglucoside.

[0075] In one example, the mass fraction of the alkali-resistant penetrant can be, but is not limited to, 0.01 parts, 0.02 parts, 0.05 parts, 0.1 parts, 0.2 parts, 0.3 parts, 0.4 parts, 0.5 parts, or a range consisting of any two of these values.

[0076] In some embodiments, the alkali-resistant penetrant includes one or more of perfluoroalkyl ethoxylate alcohol, perfluoroalkyl polyoxyethylene ether, and perfluoropolyether polyoxyethylene ether, and the weight fraction of the alkali-resistant penetrant is 0.01 to 0.1 parts. Experiments have shown that the use of the above-mentioned alkali-resistant penetrant at a weight fraction of 0.01 to 0.1 parts further improves the hydrophobicity.

[0077] Alkylsiloxane can be hydrolyzed into silanol under acidic or alkaline conditions. The surface hydroxyl groups of silanol condense with the surface hydroxyl groups of silica sol, thereby attaching hydrophobic alkyl or fluorine-substituted alkyl groups to the surface of silica sol. It can also be further polycondensed on the surface of silica nanoparticles to form a dense film, which greatly improves the hydrophobic properties of silica sol. Normally, alkylsiloxane will hydrolyze more completely under acidic conditions, but this application uses alkaline silica sol, and alkylsiloxane is hydrolyzed under alkaline conditions. The amount of alkylsiloxane added is 0.3 to 2 parts to complete the hydrolysis. However, in actual practice, the hydrolysis of alkylsiloxane should not be increased by adding acid to adjust the pH to acidic. On the one hand, it will reduce the stability of silica sol. Over time, inorganic silica nanoparticles will agglomerate and precipitate in large quantities, causing the coating to fail. On the other hand, acidic conditions will also greatly reduce the adhesion of the coating.

[0078] In one example, the mass fraction of alkyl siloxane can be, but is not limited to, 0.3 parts, 0.4 parts, 0.5 parts, 0.6 parts, 0.7 parts, 0.8 parts, 0.9 parts, 1 part, 1.1 parts, 1.2 parts, 1.3 parts, 1.4 parts, 1.5 parts, 1.6 parts, 1.7 parts, 1.8 parts, 1.9 parts, 2 parts, or a range consisting of any two of these values.

[0079] In some embodiments, the general structural formula of alkylsiloxane is Si(OR 1 )3R 2 , each R 1 Each includes one of C1~C3 alkyl and C2~C3 alkanoyl, R 2 Including C1~C 12 Alkyl and fluorine-substituted C1~C 12 Specifically, the alkylsiloxane includes one or more of heptafluorodecyltrimethoxysilane, tridecafluorooctyltrimethoxysilane, nonafluorohexyltrimethoxysilane, dodecyltrimethoxysilane and methyltriacetoxysilane.

[0080] In some embodiments, R 2 Including C6~C 12 Alkyl and fluorine-substituted C6~C 12 One of the alkyl groups.

[0081] Furthermore, R 2 Including fluorine-substituted C6~C 12 The use of fluorinated alkylsiloxanes is beneficial to further improve the hydrophobic properties.

[0082] In some embodiments, the coating material further comprises: 0.2 to 1 part of an adhesion promoter and 1 to 8 parts of a fluoropolymer aqueous dispersion. Adding the adhesion promoter to the coating material is beneficial for further improving the adhesion of the prepared coating.

[0083] In some embodiments, the adhesion promoter includes a phosphate ester promoter. Such adhesion promoters exhibit good solubility in aqueous systems, and their highly polar PO bonds have a high affinity for metal ions, further enhancing the coating's adhesion to the metal substrate surface. Furthermore, alkaline silica sols with branched and / or beaded morphologies cross-link and overlap during the drying and film-forming process, exhibiting excellent film-forming properties and adhesion to stainless steel filters. Combined with an organic phosphate ester adhesion promoter, the highly polar PO bonds exhibit a high affinity for metal ions, further enhancing adhesion and imparting excellent film-forming properties and adhesion to the filter substrate surface.

[0084] In some embodiments, the adhesion promoter includes one or more of 2-hydroxyethyl methacrylate phosphate, alkyl acrylate phosphate, di(methacryloyloxyethyl) hydrogen phosphate, and polyethylene glycol methacrylate phosphate.

[0085] In some embodiments, the adhesion promoter includes a phosphate ester, which also contains a hydroxyl group. Specifically, the adhesion promoter includes 2-hydroxyethyl methacrylate phosphate. In addition to providing high-affinity PO bonds, the surface hydroxyl groups of 2-hydroxyethyl methacrylate phosphate can also undergo a condensation reaction with the Si-OH groups of the silica sol, further improving the film-forming and adhesion properties of the system.

[0086] In one example, the mass fraction of the adhesion promoter can be, but is not limited to, 0.1 part, 0.2 part, 0.3 part, 0.4 part, 0.5 part, or a range consisting of any two of these values.

[0087] In some embodiments, the coating material further comprises: 1 to 8 parts of a fluoropolymer aqueous dispersion. The fluoropolymer aqueous dispersion comprises a fluoropolymer and a nonionic surfactant, with the fluoropolymer comprising 40% to 60% by weight and the nonionic surfactant comprising 4% to 6% by weight. Adding the fluoropolymer aqueous dispersion to the coating material not only helps to create a micro-nano rough structure with the silica nanoparticles in the silica sol, but also helps to further enhance the hydrophobic properties of the resulting coating. Furthermore, the low surface energy of the fluoropolymer can further improve the coating's wear resistance.

[0088] In some embodiments, the fluoropolymer water-based dispersion includes one of a PTFE (polytetrafluoroethylene) dispersion, a PFA (perfluoroalkoxy resin) dispersion, and a FEP (fluorinated ethylene propylene copolymer) dispersion.

[0089] In some embodiments, the aqueous fluoropolymer dispersion includes an FEP dispersion. The aqueous fluoropolymer dispersion can be effectively dispersed in an alkaline silica sol system containing a penetrant. After high-temperature baking in the coexistence of alkylsiloxane and silica sol, the unmelted portion of the FEP and the silica nanoparticles in the silica sol jointly construct a micro-nano rough structure, laying the microstructural foundation for hydrophobicity. The nano-silica has high hardness, providing mechanical strength, and the low surface energy of the FEP further reduces the surface energy of the coating. The alkylsiloxane bonds with the Si-OH groups on the silica sol surface, and the melted portion of the FEP fills the pores of the silica sol, forming a continuous fluorocarbon phase, further constructing a hydrophobic layer.

[0090] In one example, the weight fraction of the fluoropolymer aqueous dispersion may be, but is not limited to, 1 part, 2 parts, 3 parts, 4 parts, 5 parts, 6 parts, 7 parts, 8 parts, or a range consisting of any two of these values.

[0091] A second aspect of the present application provides a filter screen, comprising a filter screen substrate and a coating provided on the surface of the filter screen substrate, wherein the coating is made of the coating material of the first aspect.

[0092] In some embodiments, the filter substrate is made of one or more materials selected from the group consisting of stainless steel, nylon, polyethylene, and polypropylene. In one embodiment, the filter substrate is made of stainless steel. The surface of stainless steel typically contains a large number of hydroxyl groups, which facilitates the strong adhesion of the coating. In other embodiments, the filter substrate is made of one or more materials selected from the group consisting of nylon, polyethylene, and polypropylene. Nylon, polyethylene, and polypropylene do not have hydroxyl groups on their surfaces. In order for the coating to firmly adhere to the surface of the filter substrate, the filter substrate is typically subjected to a surface hydroxylation treatment, such as plasma treatment, to impart hydroxyl groups to the surface of the filter substrate.

[0093] In some embodiments, the average pore size of the filter substrate is 40 μm to 100 μm. For example, the average pore size of the filter substrate can be, but is not limited to, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, or a range consisting of any two of these values.

[0094] In some embodiments, the coating has a thickness of 1 μm to 10 μm. For example, the coating thickness may be, but is not limited to, 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, or a range consisting of two of these values. At these coating thicknesses, the coating will not clog the filter substrate mesh and will exhibit good adhesion and wear resistance.

[0095] A third aspect of the present application provides a method for preparing a filter screen, comprising the following steps:

[0096] A coating material is applied to the surface of the filter substrate and solidified to form a coating on the surface of the filter substrate to prepare the filter. The coating material is the same as the first aspect mentioned above.

[0097] In some embodiments, the step of applying the coating material on the surface of the filter screen substrate includes: soaking the filter screen substrate in the coating material for 60 seconds to 120 seconds, taking it out, and drying the surface for 5 minutes to 10 minutes.

[0098] In some embodiments, the curing step includes heating at 60°C to 90°C for 10 to 20 minutes, then heating at 150°C to 210°C for 20 to 40 minutes. Curing under the above conditions allows the solvent to fully evaporate and improves the curing effect.

[0099] In some embodiments, before applying the coating material on the surface of the filter screen substrate, the method further includes subjecting the filter screen substrate to a surface hydroxylation treatment to further improve the adhesion of the coating.

[0100] Optionally, the surface of the filter screen substrate is hydroxylated by plasma treatment.

[0101] In some embodiments, the filter screen substrate is made of one or more materials selected from the group consisting of stainless steel, nylon, polyethylene, and polypropylene. In one embodiment, the filter screen substrate is made of stainless steel. The surface of stainless steel generally contains a large amount of hydroxyl groups, which facilitates the strong adhesion of the coating. Therefore, surface hydroxylation treatment is not required. In other embodiments, the filter screen substrate is made of one or more materials selected from the group consisting of nylon, polyethylene, and polypropylene. The surfaces of nylon, polyethylene, and polypropylene do not have hydroxyl groups. In order to ensure that the coating can be firmly adhered to the surface of the filter screen substrate, the filter screen substrate is generally required to be subjected to surface hydroxylation treatment, such as plasma treatment, so that the surface of the filter screen substrate contains hydroxyl groups.

[0102] In some embodiments, before performing the surface hydroxylation treatment on the filter screen substrate, the step further includes degreasing and decontaminating the surface of the filter screen substrate.

[0103] In some embodiments, the steps of preparing the coating material include:

[0104] Mix the alkali-resistant penetrant and the porcelain liquid;

[0105] The obtained mixture is mixed with alkylsiloxane and stirred to prepare a coating material.

[0106] In some embodiments, the step of mixing the resulting mixture with the alkyl siloxane is performed at a stirring speed of 300 rpm to 500 rpm for a time of 60 to 120 minutes. These conditions facilitate thorough mixing of the alkyl siloxane with the mixture and prevent further reaction of the alkyl siloxane. If the reaction time is too long, the alkyl siloxane may react further, resulting in a small amount of gel forming at the bottom.

[0107] In other embodiments, the coating material further comprises: an adhesion promoter and a fluoropolymer water-based dispersion, and the steps of preparing the coating material include:

[0108] Mix the alkali-resistant penetrant and the porcelain liquid;

[0109] The obtained mixture is mixed with the fluoropolymer dispersion, and then the alkylsiloxane and adhesion promoter are added and mixed to prepare a coating material. Figure 1 , the preparation method of the filter screen comprises the following steps:

[0110] Step S110: mixing and stirring the alkali-resistant penetrant and the porcelainizing liquid.

[0111] Step S120: mixing the obtained mixture with a fluoropolymer dispersion, and then adding alkyl siloxane and an adhesion promoter, mixing and stirring to prepare a coating material.

[0112] Step S130: performing surface hydroxylation treatment on the filter screen substrate.

[0113] Step S140: Soak the filter screen substrate after surface hydroxylation treatment in the coating material for 60s~120s, take it out, dry the surface for 5min~10min, heat it at 60℃~90℃ for 10min~20min, raise the temperature to 150℃~210℃ and heat it for 20min~40min to obtain the filter screen.

[0114] In order to make the purpose and advantages of the present application clearer, the coating material, filter screen and its effects of the present application are further described in detail below in conjunction with specific examples. It should be understood that the specific examples described here are only used to explain the present application and shall not be used to limit the present application. The following examples do not include other components except unavoidable impurities unless otherwise specified. The drugs and instruments used in the examples are all conventionally selected in the art unless otherwise specified. The experimental methods for which specific conditions are not specified in the examples are implemented according to conventional conditions, such as the conditions described in the literature, books or the methods recommended by the manufacturer.

[0115] Example 1

[0116] This embodiment provides a stainless steel filter screen, comprising a filter screen substrate and a coating disposed on the surface of the filter screen substrate, the coating being made of a coating material. The coating material comprises, by weight, 100 parts of a ceramic liquid, 0.4 parts of a C6-C8 alkyl polyglucoside as an alkali-resistant penetrant, 0.8 parts of a tridecafluorooctyltrimethoxysilane as an alkyl siloxane, 0.5 parts of a 2-hydroxyethyl methacrylate phosphate as an adhesion promoter, and 4 parts of a FEP dispersion (50% by weight) as a fluoropolymer aqueous dispersion. The ceramic liquid is prepared using an alkaline silica sol containing 4% by weight of silica nanoparticles. The particles are branched, have an average particle size of 8 nm, and a pH of 12.

[0117] The method for preparing the stainless steel filter screen of this embodiment includes the following steps:

[0118] (1) Weigh 0.4 parts of alkali-resistant penetrant and add it to 100 parts of porcelain liquid and stir evenly so that the alkali-resistant penetrant is evenly dispersed in the porcelain liquid.

[0119] (2) Slowly add 4 parts of the fluoropolymer water-based dispersion to the mixture of step (1), and stir at a stirring speed of 300 rpm for 60 minutes to ensure that the fluoropolymer water-based dispersion is evenly dispersed in the porcelain liquid containing the alkali-resistant penetrant.

[0120] (3) Weigh 0.8 parts of alkyl siloxane and 0.5 parts of adhesion promoter and add them to the mixture of step (2), and stir at a stirring speed of 400 rpm for 50 minutes to prepare a coating material.

[0121] (4) After degreasing and cleaning the surface of the stainless steel filter mesh substrate, the substrate was immersed in the coating material of step (4) for 70 seconds, taken out and dried for 10 minutes, baked in a 65°C oven for 15 minutes, and then transferred to a 190°C oven for 30 minutes to obtain the stainless steel filter mesh of this embodiment.

[0122] Example 2

[0123] This embodiment provides a stainless steel filter screen, which is similar to the stainless steel filter screen of Example 1, except that the alkylsiloxane in the coating material is different. Specifically, the stainless steel filter screen of this embodiment includes a filter screen substrate and a coating provided on the surface of the filter screen substrate, and the coating is made of a coating material. Among them, the coating material includes, by mass, 100 parts of a ceramic liquid, 0.4 parts of a C6-C8 alkyl polyglucoside as an alkali-resistant penetrant, 0.8 parts of a dodecyltrimethoxysilane as an alkylsiloxane, 0.5 parts of a 2-hydroxyethyl methacrylate phosphate as an adhesion promoter, and 4 parts of a FEP dispersion (50% by mass of a fluoropolymer) as a water-based fluoropolymer dispersion. Among them, the ceramic liquid is prepared using an alkaline silica sol containing 4% by mass of silica nanoparticles, the particles are branched in morphology, the average particle size is 8 nm, and the pH is 12.

[0124] The preparation method of the stainless steel filter screen of this embodiment is the same as that of embodiment 1 and will not be repeated here.

[0125] Example 3

[0126] This embodiment provides a stainless steel filter screen, which is similar to the stainless steel filter screen of Example 1, except that the coating material does not contain an adhesion promoter. Specifically, the stainless steel filter screen of this embodiment includes a filter screen substrate and a coating provided on the surface of the filter screen substrate, and the coating is made of a coating material. Among them, the coating material includes, by mass, 100 parts of a porcelain liquid, 0.4 parts of a C6-C8 alkyl polyglucoside as an alkali-resistant penetrant, 0.8 parts of a tridecafluorooctyltrimethoxysilane as an alkyl siloxane, and 4 parts of a FEP dispersion (50% by mass of a fluoropolymer) as a water-based fluoropolymer dispersion. The porcelain liquid is prepared using an alkaline silica sol containing 4% by mass of silica nanoparticles, the particles are branched in morphology, the average particle size is 8 nm, and the pH is 12.

[0127] The preparation method of the stainless steel filter screen of this embodiment is the same as that of embodiment 1 and will not be repeated here.

[0128] Example 4

[0129] This embodiment provides a stainless steel filter screen, which is similar to the stainless steel filter screen of Example 1, except that the adhesion promoter in the coating material is an alkyl acrylate phosphate. Specifically, the stainless steel filter screen of this embodiment includes a filter screen substrate and a coating provided on the surface of the filter screen substrate, and the coating is made of a coating material. The coating material comprises, by weight, 100 parts of a ceramic liquid, 0.4 parts of a C6-C8 alkyl polyglucoside as an alkali-resistant penetrant, 0.8 parts of a tridecafluorooctyltrimethoxysilane as an alkyl siloxane, 0.5 parts of an alkyl acrylate phosphate as an adhesion promoter, and 4 parts of a FEP dispersion (50% by weight of a fluoropolymer aqueous dispersion) as a fluoropolymer aqueous dispersion. The ceramic liquid is prepared using an alkaline silica sol containing 4% by weight of silica nanoparticles, the particles are branched, the average particle size is 8 nm, and the pH is 12.

[0130] The preparation method of the stainless steel filter screen of this embodiment is the same as that of embodiment 1 and will not be repeated here.

[0131] Example 5

[0132] This embodiment provides a stainless steel filter screen, comprising a filter screen substrate and a coating disposed on the surface of the filter screen substrate, wherein the coating is made of a coating material. The coating material comprises, by weight, 100 parts of a ceramic liquid, 0.01 parts of a perfluoroalkyl polyoxyethylene ether as an alkali-resistant penetrant, 1.5 parts of heptadecafluorodecyltrimethoxysilane as an alkyl siloxane, 0.3 parts of di(methacryloyloxyethyl) hydrogen phosphate as an adhesion promoter, and 4 parts of a PTFE dispersion (containing 50% by weight of a fluoropolymer) as an aqueous fluoropolymer dispersion. The ceramic liquid is prepared using an alkaline silica sol containing 4% by weight of silica nanoparticles. The particles are beaded in shape, have an average particle size of 15 nm, and a pH of 11.

[0133] The method for preparing the stainless steel filter screen of this embodiment includes the following steps:

[0134] (1) Weigh 0.01 parts of alkali-resistant penetrant and add it to 100 parts of porcelainizing liquid and stir evenly so that the alkali-resistant penetrant is evenly dispersed in the alkaline silica sol.

[0135] (2) Slowly add 4 parts of the fluoropolymer water-based dispersion to the mixture of step (1), and stir at a stirring speed of 300 rpm for 60 minutes to ensure that the fluoropolymer water-based dispersion is evenly dispersed in the porcelain liquid containing the alkali-resistant penetrant.

[0136] (3) Weigh 1.5 parts of alkyl siloxane and 0.3 parts of adhesion promoter and add them to the mixture of step (2), and stir at a stirring speed of 500 rpm for 60 minutes to prepare a coating material.

[0137] (4) After degreasing and cleaning the surface of the stainless steel filter mesh substrate, the substrate was immersed in the coating material of step (3) for 60 seconds, taken out and dried for 10 minutes, baked in an 80°C oven for 15 minutes, and then transferred to a 200°C oven for 40 minutes to obtain the stainless steel filter mesh of this embodiment.

[0138] Example 6

[0139] This embodiment provides a stainless steel filter screen, comprising a filter screen substrate and a coating disposed on the surface of the filter screen substrate, the coating being made of a coating material. The coating material comprises, by weight, 100 parts of a ceramic liquid, 0.4 parts of a C6-C8 alkyl polyglucoside as an alkali-resistant penetrant, 0.6 parts of nonafluorohexyltrimethoxysilane and 0.1 parts of methylacetoxysilane as alkyl siloxanes, 0.5 parts of 2-hydroxyethyl methacrylate phosphate as an adhesion promoter, and 4 parts of a FEP dispersion (50% by weight) as a fluoropolymer aqueous dispersion. The ceramic liquid is prepared using an alkaline silica sol containing 6% by weight of silica nanoparticles. The particles are beaded in shape, have an average particle size of 3 nm, and a pH of 12.

[0140] The method for preparing the stainless steel filter screen of this embodiment includes the following steps:

[0141] (1) Weigh 0.4 parts of alkali-resistant penetrant and add it to 100 parts of porcelainizing liquid and stir evenly so that the alkali-resistant penetrant is evenly dispersed in the alkaline silica sol.

[0142] (2) Slowly add 4 parts of the fluoropolymer water-based dispersion to the mixture of step (1), and stir at a stirring speed of 300 rpm for 60 minutes to ensure that the fluoropolymer water-based dispersion is evenly dispersed in the porcelain liquid containing the alkali-resistant penetrant.

[0143] (3) Weigh 0.7 parts of alkylsiloxane (0.6 parts of nonafluorohexyltrimethoxysilane and 0.1 parts of methylacetoxysilane) and 0.3 parts of adhesion promoter and add them to the mixture of step (2). Stir at a stirring speed of 400 rpm for 120 minutes to prepare a coating material.

[0144] (4) After degreasing and cleaning the surface of the stainless steel filter mesh substrate, immerse it in the coating material of step (3) for 80 seconds, take it out and dry the surface for 8 minutes, bake it in an 80°C oven for 20 minutes, and then bake it in a 200°C oven for 30 minutes to obtain the stainless steel filter mesh of this embodiment.

[0145] Example 7

[0146] The present embodiment provides a stainless steel filter screen, which is similar to the stainless steel filter screen of Example 1, except that no fluoropolymer water-based dispersion is added to the coating material. Specifically, the stainless steel filter screen of the present embodiment includes a filter screen substrate and a coating provided on the surface of the filter screen substrate, and the coating is made of a coating material. Among them, in parts by mass, the coating material includes: 100 parts of porcelain liquid, 0.4 parts of C6~C8 alkyl polyglucoside as an alkali-resistant penetrant, 0.8 parts of tridecafluorooctyltrimethoxysilane as an alkyl siloxane, and 0.5 parts of 2-hydroxyethyl methacrylate phosphate as an adhesion promoter. Among them, the porcelain liquid is prepared from alkaline silica sol with a mass percentage of 4% of silica nanoparticles, the particle morphology is branched, the average particle size is 8nm, and the pH is 12.

[0147] The preparation method of the stainless steel filter screen of this embodiment is the same as that of embodiment 1 and will not be repeated here.

[0148] Comparative Example 1

[0149] Comparative Example 1 provides a stainless steel filter screen, similar to the stainless steel filter screen of Example 1, except that the coating material does not contain a porcelainizing liquid. Specifically, the stainless steel filter screen of Comparative Example 1 comprises a filter screen substrate and a coating disposed on the surface of the filter screen substrate, the coating being made of a coating material. The coating material comprises, by weight, 0.4 parts of a C6-C8 alkyl polyglucoside as an alkali-resistant penetrant, 0.8 parts of a tridecafluorooctyltrimethoxysilane as an alkyl siloxane, 0.5 parts of a 2-hydroxyethyl methacrylate phosphate as an adhesion promoter, and 4 parts of a FEP dispersion (50% by weight) as a fluoropolymer aqueous dispersion.

[0150] The preparation method of the stainless steel filter screen of Comparative Example 1 is the same as that of Example 1 and will not be repeated here.

[0151] Comparative Example 2

[0152] Comparative Example 2 provides a stainless steel filter screen, similar to the stainless steel filter screen of Example 2, except that the particles in the porcelainizing liquid of the coating material are spherical. Specifically, the stainless steel filter screen of Comparative Example 2 comprises a filter screen substrate and a coating disposed on the surface of the filter screen substrate, the coating being made of a coating material. The coating material comprises, by weight, 100 parts of porcelainizing liquid, 0.4 parts of a C6-C8 alkyl polyglucoside as an alkali-resistant penetrant, 0.8 parts of dodecyltrimethoxysilane as an alkyl siloxane, 0.5 parts of 2-hydroxyethyl methacrylate phosphate as an adhesion promoter, and 4 parts of a fluoropolymer aqueous dispersion (50% by weight of FEP dispersion). The porcelainizing liquid is prepared using an alkaline silica sol containing 4% by weight of silica nanoparticles. The particles are spherical, with an average particle size of 8 nm and a pH of 12.

[0153] The preparation method of the stainless steel filter screen of Comparative Example 2 is the same as that of Example 2 and will not be repeated here.

[0154] Comparative Example 3

[0155] Comparative Example 3 provides a stainless steel filter screen, similar to the stainless steel filter screen of Example 2, except that the coating material replaces the porcelainizing solution in Example 2 with a fumed nanosilica aqueous solution. Specifically, the stainless steel filter screen of Comparative Example 3 includes a filter screen substrate and a coating disposed on the surface of the filter screen substrate, the coating being made of a coating material. The coating material comprises, by weight, 100 parts of a fumed nanosilica aqueous solution, 0.4 parts of a C6-C8 alkyl polyglucoside as an alkali-resistant penetrant, 0.8 parts of dodecyltrimethoxysilane as an alkyl siloxane, 0.5 parts of 2-hydroxyethyl methacrylate phosphate as an adhesion promoter, and 4 parts of a FEP dispersion (50% solids content) as a fluoropolymer aqueous dispersion. The nanosilica in the fumed nanosilica aqueous solution has a mass percentage of 4%, spherical particles with an average particle size of 8 nm, and a pH of 12.

[0156] The preparation method of the stainless steel filter screen of Comparative Example 3 is the same as that of Example 2 and will not be repeated here.

[0157] Comparative Example 4

[0158] Comparative Example 4 provides a stainless steel filter screen similar to the stainless steel filter screen of Example 4, except that the coating material replaces the porcelainizing solution in Example 4 with an acidic silica sol having a pH of 5. Specifically, the stainless steel filter screen of Comparative Example 4 comprises a filter screen substrate and a coating disposed on the surface of the filter screen substrate, the coating being made of a coating material. The coating material comprises, by weight, 100 parts of the porcelainizing solution, 0.4 parts of a C6-C8 alkyl polyglucoside as an alkali-resistant penetrant, 0.8 parts of a tridecafluorooctyltrimethoxysilane as an alkyl siloxane, 0.5 parts of an alkyl acrylate phosphate as an adhesion promoter, and 4 parts of an FEP dispersion (50% by weight) as an aqueous fluoropolymer dispersion. The porcelainizing solution is prepared using an acidic silica sol containing 2% by weight of silica nanoparticles. The particles are branched, have an average particle size of 8 nm, and have a pH of 5.

[0159] The preparation method of the stainless steel filter screen of Comparative Example 4 is the same as that of Example 4 and will not be repeated here.

[0160] Comparative Example 5

[0161] Comparative Example 5 provides a stainless steel filter screen, similar to the stainless steel filter screen of Example 5, except that the mass percentage of silica nanoparticles in the porcelainizing liquid of the coating material is 10%. Specifically, the stainless steel filter screen of Comparative Example 5 includes a filter screen substrate and a coating disposed on the surface of the filter screen substrate, the coating being made of a coating material. The coating material comprises, by mass, 100 parts of porcelainizing liquid, 0.01 parts of perfluoroalkyl polyoxyethylene ether as an alkali-resistant penetrant, 1.5 parts of heptadecafluorodecyltrimethoxysilane as an alkyl siloxane, 0.3 parts of di(methacryloyloxyethyl) hydrogen phosphate as an adhesion promoter, and 4 parts of PTFE dispersion (50% by mass of fluoropolymer) as an aqueous fluoropolymer dispersion. The porcelainizing liquid is prepared using an alkaline silica sol containing 10% by mass of silica nanoparticles. The particles are branched, with an average particle size of 15 nm and a pH of 11.

[0162] The preparation method of the stainless steel filter screen of Comparative Example 5 is the same as that of Example 5 and will not be repeated here.

[0163] Comparative Example 6

[0164] Comparative Example 6 provides a stainless steel filter screen, similar to the stainless steel filter screen of Example 6, except that the alkali-resistant penetrant is 0.8 parts. Specifically, the stainless steel filter screen of Comparative Example 6 includes a filter screen substrate and a coating disposed on the surface of the filter screen substrate, the coating being made of a coating material. The coating material comprises, by weight, 100 parts of a ceramic liquid, 0.8 parts of a C6-C8 alkyl polyglucoside as the alkali-resistant penetrant, 0.6 parts of nonafluorohexyltrimethoxysilane and 0.1 parts of methylacetoxysilane as the alkyl siloxane, 0.5 parts of 2-hydroxyethyl methacrylate phosphate as the adhesion promoter, and 4 parts of a FEP dispersion (50% by weight) as the aqueous fluoropolymer dispersion. The ceramic liquid is prepared using an alkaline silica sol containing 6% by weight of silica nanoparticles. The particles are beaded, with an average particle size of 3 nm and a pH of 12.

[0165] The preparation method of the stainless steel filter screen of Comparative Example 6 is the same as that of Example 6 and will not be repeated here.

[0166] Comparative Example 7

[0167] The comparative example provides a stainless steel filter screen, which is similar to the stainless steel filter screen of Example 1, except that the coating material does not contain an alkali-resistant penetrant. Specifically, the stainless steel filter screen of Comparative Example 7 includes a filter screen substrate and a coating disposed on the surface of the filter screen substrate, wherein the coating is made of a coating material. The coating material comprises, by weight, 100 parts of a ceramic liquid, 0.8 parts of tridecafluorooctyltrimethoxysilane as an alkyl siloxane, 0.5 parts of 2-hydroxyethyl methacrylate phosphate as an adhesion promoter, and 4 parts of an FEP dispersion (50% by weight of a fluoropolymer) as an aqueous fluoropolymer dispersion. The ceramic liquid is prepared using an alkaline silica sol containing 4% by weight of silica nanoparticles, the particles are branched, have an average particle size of 8 nm, and a pH of 12.

[0168] The preparation method of the stainless steel filter screen of Comparative Example 7 is the same as that of Example 1 and will not be repeated here.

[0169] Comparative Example 8

[0170] Comparative Example 8 provides a stainless steel filter screen, similar to the stainless steel filter screen of Example 1, except that the alkali-resistant penetrant in the coating material is different. Specifically, the stainless steel filter screen of Comparative Example 8 includes a filter screen substrate and a coating disposed on the surface of the filter screen substrate, the coating being made of a coating material. The coating material comprises, by weight, 100 parts of a ceramic liquid, 0.4 parts of octadecyltrimethylammonium chloride, 0.8 parts of tridecafluorooctyltrimethoxysilane as an alkyl siloxane, 0.5 parts of 2-hydroxyethyl methacrylate phosphate as an adhesion promoter, and 4 parts of an FEP dispersion (50% by weight) as a fluoropolymer aqueous dispersion. The ceramic liquid is prepared using an alkaline silica sol containing 4% by weight of silica nanoparticles. The particles are branched, with an average particle size of 8 nm and a pH of 12.

[0171] The preparation method of the stainless steel filter screen of Comparative Example 8 is the same as that of Example 1 and will not be repeated here.

[0172] Comparative Example 9

[0173] Comparative Example 9 provides a stainless steel filter screen, similar to the stainless steel filter screen of Example 1, except that the amount of alkylsiloxane used in the coating material is different. Specifically, the stainless steel filter screen of Comparative Example 9 includes a filter screen substrate and a coating disposed on the surface of the filter screen substrate, the coating being made of a coating material. The coating material comprises, by weight, 100 parts of a ceramic liquid, 0.4 parts of a C6-C8 alkyl polyglucoside as an alkali-resistant penetrant, 0.1 parts of a tridecafluorooctyltrimethoxysilane as an alkylsiloxane, 0.5 parts of a 2-hydroxyethyl methacrylate phosphate as an adhesion promoter, and 4 parts of a FEP dispersion (50% by weight) as a fluoropolymer aqueous dispersion. The ceramic liquid is prepared using an alkaline silica sol containing 4% by weight of silica nanoparticles. The particles are branched, with an average particle size of 8 nm and a pH of 12.

[0174] The preparation method of the stainless steel filter screen of Comparative Example 9 is the same as that of Example 1 and will not be repeated here.

[0175] The stainless steel filter screens of the above embodiments and comparative examples were tested to obtain the experimental data shown in Table 1 below.

[0176] The test of the hydrophobic static contact angle is carried out according to the following steps:

[0177] a) Take three pre-filter screens treated with a hydrophobic coating and test them at five different locations on each screen. The screens should not rotate during the test, and water should fall on the highest point of the screen.

[0178] b) Use grade 3 water that complies with GB / T 6682 as the reagent, with a reagent volume of 4 μL to 5 μL for each test, and conduct the test in accordance with the provisions of GB / T 30693;

[0179] c) The arithmetic mean of the five test points of each filter sample is taken as the contact angle value of the filter sample;

[0180] d) The test results are expressed as the arithmetic mean of the test results of three filter samples.

[0181] The test method for wear resistance is:

[0182] a) Use a wet friction tester. The total mass of the fixture, weight, and sieve is 500 ± 10 g. The brush is a 90 mm × 38 mm × 25 mm (length × width × thickness) black boar bristle brush with 60 ± 1 holes, a 3 mm aperture, and a bristle length of approximately 19 mm.

[0183] b) Cut the filter along the weld seam and fix it horizontally on the test bench of the wet friction tester.

[0184] c) Place the pretreated brush on the hydrophobic coating surface of the sample, allowing the brush to hang naturally and contact the filter coating. Add 2mL~5mL of distilled water or deionized water to the test area of ​​the sample.

[0185] d) Start the wet abrasion tester and rub the hydrophobic coating on the specimen back and forth while simultaneously adding distilled or deionized water at a rate of approximately 0.04 mL per second to keep the abrasion surface moist. Record the number of scrubbing cycles using a counter. Stop the test when the specified number of scrubbing cycles is reached. Remove the specimen and immediately rinse with tap water. After it is completely dry, wipe it clean with alcohol.

[0186] e) Static contact angle after friction testing.

[0187] The test method for boiling water resistance is:

[0188] Place the filter into a constant temperature water tank filled with (65±1)℃ distilled water and soak it for 100h±10min. Check the coating surface for discoloration, bubbles, shedding, cracking, powdering, etc.

[0189] The water flow test method is:

[0190] Install the stainless steel filter mesh onto the pre-filter element and install the pre-filter according to the requirements. Test with tap water at room temperature at an inlet pressure of (0.2±0.02) MPa. Close the drain outlet and allow the water to flow normally for 5 minutes. Collect water at the outlet sampling port for (60±1) seconds. Weigh and calculate the water flow rate and convert it into L / min.

[0191] Table 1

[0192]

[0193] It can be seen from the experimental data of the above embodiments and comparative examples that the filter screen prepared using the coating material of the embodiment of the present application has good hydrophobicity, making it difficult for fine particles to adhere, and the prepared coating can have good adhesion to the filter screen substrate while not easily clogging the filter screen mesh.

[0194] Specifically, it can be seen from the comparison between Example 1 and Example 2 that the selection of fluorine-containing alkylsiloxane is conducive to further increasing the hydrophobic static contact angle, thereby improving the hydrophobic performance.

[0195] From the comparison between Example 1 and Example 3, it can be seen that the addition of an adhesion promoter is beneficial to further improving the adhesion and wear resistance of the coating.

[0196] From the comparison between Example 1 and Example 4, it can be seen that by further improving the adhesion promoter, using an organic phosphate adhesion promoter, utilizing its high polarity PO bond with high affinity for metal ions, and combining it with branched and / or beaded alkaline silica sol, which cross-overlaps with each other during the drying and film-forming process, it is beneficial to further improve the adhesion and wear resistance of the coating.

[0197] From the comparison between Example 1 and Example 7, it can be seen that by adding a fluoropolymer water-based dispersion and cooperating with the silica nanoparticles in the silica sol to jointly construct a micro-nano rough structure, it is beneficial to further improve the contact angle and hydrophobic properties of the prepared coating; in addition, utilizing the low surface energy characteristics of the fluoropolymer is beneficial to further improve the wear resistance of the coating.

[0198] From the comparison between Example 1 and Comparative Example 1, it can be seen that in Comparative Example 1, no porcelainizing liquid was added, and the surface rigidity of the prepared coating was insufficient, and the wear resistance and adhesion were poor.

[0199] A comparison of Example 2 and Comparative Example 2 shows that the spherical inorganic silica nanoparticles used in Comparative Example 2 exhibit a good initial contact angle, but poor abrasion resistance, and the coating easily falls off. In contrast, the branched and / or beaded silica sols used in the examples exhibit cross-linking during the drying and film-forming process, resulting in significantly better film-forming performance and metal adhesion than conventional spherical silica sols.

[0200] From the comparison of Example 2 and Comparative Example 3, it can be seen that in Comparative Example 3, the use of a fumed nano-silica aqueous solution instead of the porcelain solution in Example 1 results in poor film-forming properties and adhesion. Although a micro-nano structure can be formed to improve the hydrophobicity, for example, the initial contact angle of the prepared coating is very good, the coating is very easy to fall off and lose its hydrophobicity, and the wear resistance is extremely poor. For example, if it is lightly wiped by hand, the hydrophobicity of the coating disappears, resulting in it being unable to be used normally.

[0201] From the comparison between Example 4 and Comparative Example 4, it can be seen that in Comparative Example 4, the acidic silica sol is used to prepare a coating with a good initial contact angle and a certain hydrophobic property. However, after the wear resistance test, the contact angle decreases significantly, indicating that its adhesion is insufficient.

[0202] From the comparison between Example 5 and Comparative Example 5, it can be seen that in Comparative Example 5, the mass percentage of silicon dioxide nanoparticles in the porcelainizing solution is too high, the water flow rate is significantly reduced, and the filter mesh is blocked.

[0203] From the comparison between Example 6 and Comparative Example 6, it can be seen that in Comparative Example 6, the amount of the penetrant used is too high, and the hydrophobicity of the prepared coating is poor.

[0204] From the comparison between Example 1 and Comparative Example 7, it can be seen that no alkali-resistant penetrant was added in Comparative Example 7, and the prepared stainless steel filter screen had poor or no local hydrophobicity, resulting in a low average contact angle and uneven hydrophobicity.

[0205] From the comparison between Example 1 and Comparative Example 8, it can be seen that the alkali-resistant penetrant in Comparative Example 8 is improperly selected. For example, the cationic penetrant will react with SiO2 in the silica sol. - The reaction will cause the silica sol system to become unstable, resulting in turbidity, precipitation or flocculation, and the inability to form a film, resulting in a very small contact angle and poor hydrophobicity. In addition, if the HLB value of the added alkali-resistant penetrant is too high and the hydrophilicity is too strong, a small amount of penetrant will still remain after the coating is heated and cured, resulting in hydrophilic points on the filter surface and poor hydrophobicity.

[0206] From the comparison between Example 1 and Comparative Example 9, it can be seen that the amount of alkylsiloxane used in Comparative Example 9 is too small, the hydrophobicity of the prepared coating is poor, and the contact angle decreases significantly during repeated friction.

[0207] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0208] The embodiments described above only express several implementation methods of the present application, which are convenient for understanding the technical solutions of the present application in a specific and detailed manner, but they cannot be understood as limiting the scope of protection of the invention patent. It should be pointed out that for ordinary technicians in this field, without departing from the concept of the present application, several variations and improvements can be made, which all fall within the scope of protection of the present application. It should be understood that the technical solutions obtained by those skilled in the art through logical analysis, reasoning or limited experiments on the basis of the technical solutions provided in the present application are all within the scope of protection of the claims attached to the present application. Therefore, the scope of protection of the patent of this application shall be based on the content of the attached claims, and the description and drawings can be used to interpret the content of the claims.

Claims

1. A coating material, characterized in that: Calculated by mass, it includes: 100 parts of porcelain liquid, 0.01 to 0.5 parts of alkali-resistant penetrant and 0.3 to 2 parts of alkyl siloxane; The porcelainizing liquid comprises alkaline silica sol, and the alkaline silica sol comprises one or both of branched silica sol and beaded silica sol. In the porcelainizing liquid, the mass percentage of silicon dioxide nanoparticles in the porcelainizing liquid is 2% to 8%; The alkali-resistant penetrant is selected from one or more of a nonionic penetrant and an anionic penetrant, and has an HLB value of 7-16.

2. The coating material according to claim 1, characterized in that The porcelainizing liquid satisfies one or more of the following conditions: (1) The pH of the porcelainizing solution is 10-13. Optionally, the pH of the porcelainizing solution is 10-12. (2) The average particle size of the silica nanoparticles is 2 nm to 50 nm; optionally, the average particle size of the silica nanoparticles is 2 nm to 15 nm; (3) The porcelainizing solution also includes a corrosion inhibitor.

3. The coating material according to claim 1, characterized in that The alkali-resistant penetrant is a non-ionic penetrant; Optionally, the alkali-resistant penetrant includes one or more of alkyl polyglucoside, fatty alcohol polyoxyethylene polyoxypropylene ether, nonylphenol polyoxyethylene ether, perfluoroalkyl ethoxy ether alcohol, perfluoroalkyl polyoxyethylene ether and perfluoropolyether polyoxyethylene ether; Optionally, the alkali-resistant penetrant includes one or more of perfluoroalkyl ethoxy ether alcohol, perfluoroalkyl polyoxyethylene ether and perfluoropolyether polyoxyethylene ether, and the mass fraction of the alkali-resistant penetrant is 0.01 part to 0.1 part.

4. The coating material according to claim 1, characterized in that The general structural formula of the alkylsiloxane is Si(OR 1 )3R 2 , each R 1 Each includes one of C1~C3 alkyl and C2~C3 alkanoyl, R 2 Including C1~C 12 Alkyl and fluorine-substituted C1~C 12 One of the alkyl groups; Optionally, R 2 Including C6~C 12 Alkyl and fluorine-substituted C6~C 12 One of the alkyl groups; Optionally, the alkylsiloxane includes one or more of heptadecafluorodecyltrimethoxysilane, tridecafluorooctyltrimethoxysilane, nonafluorohexyltrimethoxysilane and dodecyltrimethoxysilane.

5. The coating material according to any one of claims 1 to 4, characterized in that The coating material further comprises: 0.2 to 1 part of an adhesion promoter and 1 to 8 parts of a fluoropolymer water-based dispersion.

6. The coating material according to claim 5, characterized in that The adhesion promoter includes a phosphate ester promoter; Optionally, the adhesion promoter includes one or more of 2-hydroxyethyl methacrylate phosphate, alkyl acrylate phosphate, di(methacryloyloxyethyl) hydrogen phosphate and polyethylene glycol methacrylate phosphate; Optionally, the adhesion promoter comprises 2-hydroxyethyl methacrylate phosphate.

7. The coating material according to claim 5, characterized in that The fluoropolymer water-based dispersion comprises a fluoropolymer and a nonionic surfactant, wherein the mass percentage of the fluoropolymer in the fluoropolymer water-based dispersion is 40% to 60%, and the mass percentage of the nonionic surfactant in the fluoropolymer water-based dispersion is 4% to 6%. Optionally, the fluoropolymer water-based dispersion includes one of a polytetrafluoroethylene dispersion, a perfluoroalkoxy resin dispersion, and a fluorinated ethylene propylene copolymer dispersion; Optionally, the aqueous fluoropolymer dispersion comprises a fluorinated ethylene propylene copolymer dispersion.

8. A filter screen, characterized in that: The invention comprises a filter screen substrate and a coating arranged on the surface of the filter screen substrate, wherein the coating is made of the coating material according to any one of claims 1 to 7.

9. The filter screen according to claim 8, characterized in that The filter screen substrate is made of one or more materials selected from stainless steel, nylon, polyethylene and polypropylene; and / or, the average pore size of the filter substrate is 40 μm to 100 μm; And / or, the thickness of the coating is 1 μm to 10 μm; optionally, the thickness of the coating is 1 μm to 2 μm.

10. A method for preparing a filter screen, characterized in that: The steps include: Applying a coating material on the surface of a filter substrate and curing the coating material to form a coating on the surface of the filter substrate to prepare a filter, wherein the coating material is as described in any one of claims 1 to 7; Optionally, the step of applying a coating material on the surface of the filter screen substrate comprises: soaking the filter screen substrate in the coating material for 60 seconds to 120 seconds, taking it out and drying the surface for 5 minutes to 10 minutes; Optionally, the curing step includes: heating at 60°C to 90°C for 10 minutes to 20 minutes, raising the temperature to 150°C to 210°C and heating for 20 minutes to 40 minutes.

11. The method for preparing a filter screen according to claim 10, characterized in that: Before applying the coating material on the surface of the filter screen substrate, the step further includes performing a surface hydroxylation treatment on the filter screen substrate; Optionally, the surface of the filter screen substrate is hydroxylated by plasma treatment; And / or, the steps of preparing the coating material include: Mixing and stirring the alkali-resistant penetrant and the porcelainizing liquid; The obtained mixture is mixed with the alkylsiloxane and stirred to prepare the coating material.

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