A self-cleaning coating and a method for its preparation

Abstract

The application relates to the technical field of self-cleaning coating, in particular to a self-cleaning coating and a preparation method thereof, which comprises the following raw materials: organic fluorosilicon modified resin, B-type nanometer silicon dioxide, a leveling agent, a defoaming agent and a solvent; the preparation method comprises the following steps: (1) adding the solvent, the leveling agent and the defoaming agent into a dispersing machine, then adding the organic fluorosilicon modified resin and fully mixing to obtain a mixture; (2) adding the B-type nanometer silicon dioxide into the mixture and uniformly stirring to prepare the self-cleaning coating. In the application, the large-particle-size nanometer silicon dioxide is ultrasonically treated with an initiator azobisisobutyronitrile, part of the azobisisobutyronitrile is attached to the surface of the nanometer particles to form an initiating core, polymerization reactions of monomers occur on the surface of the initiating core, the large-particle-size nanometer silicon dioxide is fully mixed and dispersed, the large-particle-size nanometer silicon dioxide plays the role of a connecting node, and finally the overall quality of the coating is improved.

Description

Technical Field

[0001] This invention relates to the field of self-cleaning coating technology, specifically to a self-cleaning coating and its preparation method. Background Technology

[0002] Superhydrophobic self-cleaning coatings have attracted widespread attention because dust and dirt on their surfaces can be automatically removed by natural forces such as wind, rain, and gravity. Low surface energy coatings with excellent self-cleaning properties can be produced by forming copolymers of organofluorine and organosilicon.

[0003] However, fluorosilicone copolymer resins have poor abrasion resistance, and significant wear severely reduces their hydrophobic properties, limiting their applications. Adding nanofillers to fluorosilicone copolymer resins can improve the abrasion resistance and hydrophobicity of the coating. However, if the nanofillers are directly added to the resin mixture, they are difficult to disperse fully in the resin matrix, and the bonding effect between the nanofillers and the resin matrix is ​​also poor, resulting in limited improvement in coating performance. Therefore, this paper provides a self-cleaning coating and its preparation method. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a self-cleaning coating and its preparation method. Using large-particle-size nano-silica as the initiating core, the monomers undergo polymerization reactions on their surfaces, which facilitates their full dispersion and acts as a connecting node, ultimately improving the overall quality of the coating.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a self-cleaning coating comprising the following raw materials in parts by weight: 60-70 parts of organofluorine-silica modified resin, 10-15 parts of type B nano silica, 1-3 parts of leveling agent, 0.5-1 part of defoamer, and 25-35 parts of solvent.

[0006] Preferably, the organofluorosilicone modified resin is prepared as follows: S1, azobisisobutyronitrile is dissolved in anhydrous ethanol, then type A nano silica is added, and ultrasonic treatment is performed to obtain a premix; S2, methyl isobutyl ketone is added to the reactor, followed by trifluoroethyl methacrylate, γ-(methacryloyloxy)propyltrimethoxysilane and butyl acrylate, and the mixture is stirred; S3, the premix is ​​poured into the reactor, and the reaction is continued by stirring to obtain the organofluorosilicone modified resin.

[0007] Preferably, in step S1, the ratio of azobisisobutyronitrile to anhydrous ethanol is 1:1 g / ml, and the mass ratio of azobisisobutyronitrile to type A nano silica is 1:1.5.

[0008] Preferably, in steps S1-S2, the mass ratio of trifluoroethyl methacrylate, γ-(methacryloyloxy)propyltrimethoxysilane, butyl acrylate and azobisisobutyronitrile is 1.5:1:4:0.15.

[0009] Preferably, in step S3, the stirring reaction temperature is controlled at 70-75℃ and the stirring reaction time is 2-3h.

[0010] Preferably, the leveling agent is polymethyl methacrylate; the defoamer is polydimethylsiloxane; and the solvent is xylene.

[0011] Preferably, type B nano silica is prepared as follows: the surface of the nano silica is coated with silane coupling agent KH-550.

[0012] Preferably, the particle size of type A nano silica is 300-500 nm, and the particle size of type B nano silica is 50-100 nm.

[0013] This invention also provides a method for preparing a self-cleaning coating, comprising the following steps:

[0014] (1) Add solvent, leveling agent and defoamer to a disperser, then add organofluorosilicone modified resin and mix thoroughly to obtain a mixture;

[0015] (2) Add type B nano silica to the mixture and stir evenly to obtain a self-cleaning coating.

[0016] This invention provides a self-cleaning coating and its preparation method, which has the following advantages compared with the prior art:

[0017] In this invention, large-particle-size nano-silica and initiator azobisisobutyronitrile are first ultrasonically treated. Some azobisisobutyronitrile adheres to the surface of the nanoparticles, forming initiation nuclei, allowing the monomers to undergo polymerization reactions on their surfaces. This facilitates the full dispersion of the large-particle-size nano-silica and also acts as a connecting node, ultimately improving the overall quality of the coating.

[0018] The present invention adds small-particle-size modified nano-silica to the prepared organofluorosilicone modified resin, allowing it to fill the voids formed by large-particle-size nano-silica, thereby forming a more continuous micro-rough surface structure on the coating and improving the hydrophobicity of the coating. Detailed Implementation

[0019] The following embodiments are provided to illustrate the implementation of this application in detail, so that the process of how this application uses technical means to solve technical problems and achieve technical effects can be fully understood and implemented accordingly.

[0020] Example 1

[0021] A method for preparing an organofluorosilicone modified resin includes the following steps:

[0022] S1. Dissolve azobisisobutyronitrile in anhydrous ethanol at a material-to-liquid ratio of 1:1 g / ml, then add nano-silica with a particle size of 300-500 nm (i.e., type A nano-silica), and sonicate to obtain a premix. The mass ratio of azobisisobutyronitrile to type A nano-silica is 1:1.5.

[0023] S2. Add methyl isobutyl ketone to the reactor, followed by trifluoroethyl methacrylate, γ-(methacryloyloxy)propyltrimethoxysilane, and butyl acrylate, and stir. The mass ratio of trifluoroethyl methacrylate, γ-(methacryloyloxy)propyltrimethoxysilane, butyl acrylate, and azobisisobutyronitrile is 1.5:1:4:0.15.

[0024] S3. Pour the premix into the reactor, continue stirring and reacting, control the stirring and reaction temperature at 75℃, and the stirring and reaction time at 2h to obtain the organofluorosilicone modified resin.

[0025] Example 2

[0026] A self-cleaning coating comprises the following raw materials in parts by weight: 70 parts of organofluorosilicone modified resin, 10 parts of type B nano silica, 3 parts of leveling agent polymethyl methacrylate, 0.5 parts of defoamer polydimethylsiloxane, and 35 parts of solvent xylene.

[0027] The preparation of type B nano silica is as follows: the surface of nano silica is coated with silane coupling agent KH-550; the particle size of type B nano silica is 50-100nm.

[0028] A method for preparing a self-cleaning coating includes the following steps:

[0029] (1) Add solvent, leveling agent and defoamer to a disperser, then add organofluorosilicone modified resin and mix thoroughly to obtain a mixture;

[0030] (2) Add type B nano silica to the mixture and stir evenly to obtain a self-cleaning coating.

[0031] In this embodiment, the organofluorosilicone modified resin from Example 1 is used.

[0032] Example 3

[0033] A self-cleaning coating comprises the following raw materials in parts by weight: 60 parts of organofluorosilicone modified resin, 15 parts of type B nano silica, 1 part of leveling agent polymethyl methacrylate, 1 part of defoamer polydimethylsiloxane, and 25 parts of solvent xylene.

[0034] The preparation of type B nano silica is as follows: the surface of nano silica is coated with silane coupling agent KH-550; the particle size of type B nano silica is 50-100nm.

[0035] A method for preparing a self-cleaning coating includes the following steps:

[0036] (1) Add solvent, leveling agent and defoamer to a disperser, then add organofluorosilicone modified resin and mix thoroughly to obtain a mixture;

[0037] (2) Add type B nano silica to the mixture and stir evenly to obtain a self-cleaning coating.

[0038] In this embodiment, the organofluorosilicone modified resin from Example 1 is used.

[0039] Example 4

[0040] A self-cleaning coating comprises the following raw materials in parts by weight: 65 parts of organofluorosilicone modified resin, 12 parts of type B nano silica, 2 parts of leveling agent polymethyl methacrylate, 1 part of defoamer polydimethylsiloxane, and 30 parts of solvent xylene.

[0041] The preparation of type B nano silica is as follows: the surface of nano silica is coated with silane coupling agent KH-550; the particle size of type B nano silica is 50-100nm.

[0042] A method for preparing a self-cleaning coating includes the following steps:

[0043] (1) Add solvent, leveling agent and defoamer to a disperser, then add organofluorosilicone modified resin and mix thoroughly to obtain a mixture;

[0044] (2) Add type B nano silica to the mixture and stir evenly to obtain a self-cleaning coating.

[0045] In this embodiment, the organofluorosilicone modified resin from Example 1 is used.

[0046] Comparative Example 1

[0047] This is basically the same as Example 4, except for the preparation method of the organofluorosilicone modified resin.

[0048] S1. Dissolve azobisisobutyronitrile in anhydrous ethanol at a material-to-liquid ratio of 1:1 g / ml, and then sonicate to obtain a premix.

[0049] S2. Add methyl isobutyl ketone to the reactor, followed by trifluoroethyl methacrylate, γ-(methacryloyloxy)propyltrimethoxysilane, and butyl acrylate, and stir. The mass ratio of trifluoroethyl methacrylate, γ-(methacryloyloxy)propyltrimethoxysilane, butyl acrylate, and azobisisobutyronitrile is 1.5:1:4:0.15.

[0050] S3. Pour the premix into the reactor, continue stirring and reacting, control the stirring and reaction temperature at 75℃, and the stirring and reaction time at 2h to obtain the organofluorosilicone modified resin.

[0051] Comparative Example 2

[0052] This is basically the same as Example 4, except for the preparation method of the organofluorosilicone modified resin.

[0053] S1. Dissolve azobisisobutyronitrile in anhydrous ethanol at a material-to-liquid ratio of 1:1 g / ml, then add type A nano-silica with a particle size of 50-100 nm, and sonicate to obtain a premix. The mass ratio of azobisisobutyronitrile to type A nano-silica is 1:1.5.

[0054] S2. Add methyl isobutyl ketone to the reactor, followed by trifluoroethyl methacrylate, γ-(methacryloyloxy)propyltrimethoxysilane, and butyl acrylate, and stir. The mass ratio of trifluoroethyl methacrylate, γ-(methacryloyloxy)propyltrimethoxysilane, butyl acrylate, and azobisisobutyronitrile is 1.5:1:4:0.15.

[0055] S3. Pour the premix into the reactor, continue stirring and reacting, control the stirring and reaction temperature at 75℃, and the stirring and reaction time at 2h to obtain the organofluorosilicone modified resin.

[0056] Comparative Example 3

[0057] A self-cleaning coating comprises the following raw materials in parts by weight: 65 parts of organofluorosilicone modified resin, 2 parts of leveling agent polymethyl methacrylate, 1 part of defoamer polydimethylsiloxane, and 30 parts of solvent xylene.

[0058] A method for preparing organofluorosilicone modified resin: S1. Azobisisobutyronitrile (AIB) is dissolved in anhydrous ethanol at a material-to-liquid ratio of 1:1 g / ml, and ultrasonically treated to obtain a premix. S2. Methyl isobutyl ketone (MBE) is added to a reactor, followed by trifluoroethyl methacrylate (TMA), γ-(methacryloyloxy)propyltrimethoxysilane (MAS), and butyl acrylate, and the mixture is stirred. The mass ratio of MDA, MAS, γ-(methacryloyloxy)propyltrimethoxysilane, butyl acrylate, and AIB is 1.5:1:4:0.15. S3. The premix is ​​poured into the reactor, and the reaction is continued with stirring. The reaction temperature is controlled at 75℃, and the reaction time is 2 hours to obtain the organofluorosilicone modified resin.

[0059] A method for preparing a self-cleaning coating includes the following steps:

[0060] (1) Add solvent, leveling agent and defoamer to a disperser, then add organofluorosilicone modified resin and mix thoroughly to obtain a mixture;

[0061] (2) Add type B nano silica to the mixture and stir evenly to obtain a self-cleaning coating.

[0062] Quality Inspection

[0063] 1. The self-cleaning coatings described in Examples 2-4 and Comparative Examples 1-3 were sprayed onto a plastic board and dried to obtain the corresponding coatings. The contact angle and roll-off angle of the corresponding coatings were measured using a contact angle measuring instrument (SDC-100S). The specific results are shown in the table below.

[0064] Table 1 Hydrophobicity

[0065]

[0066] In the friction test: load 10N / 100mm 2 The rotation speed is 100 r / min.

[0067] From the table above, we can see that:

[0068] (1) Compared with Example 4, the difference in hydrophobicity and wear resistance of the coating in Comparative Example 1 indicates that with type A nano silica as the initiating core, each monomer is directly polymerized on its surface, which is beneficial to the uniform dispersion of type A nano silica and acts as a connecting node, thus improving the hydrophobicity and wear resistance of the final coating.

[0069] (2) Compared with Example 4, the hydrophobicity and wear resistance of the coating in Comparative Example 2 are slightly worse, indicating that the use of Type A nano silica and Type B nano silica with different particle sizes, wherein the small-sized particles fill the spaces between the large particles, forming a micro-rough structure on the coating surface, thereby improving the hydrophobicity.

[0070] (3) Compared with Example 4 and Comparative Example 1, the coating performance in Comparative Example 3 was the worst, indicating that the combined use of Type A nano silica and Type B nano silica can further improve the coating quality.

[0071] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A self-cleaning coating, characterized in that, The following raw materials by weight are included: organic fluorosilicon modified resin 60-70 parts, type B nano-silica 10-15 parts, leveling agent 1-3 parts, defoaming agent 0.5-1 part, solvent 25-35 parts; The organic fluorosilicon modified resin is prepared as follows: S1, dissolve azobisisobutyronitrile in anhydrous ethanol, then add type A nano-silica, and ultrasonically treat to obtain a premix; S2, add methyl isobutyl ketone to a reactor, then add trifluoroethyl methacrylate, γ-(methacryloyloxy) propyl trimethoxysilane and butyl acrylate, and stir; S3, pour the premix into the reactor, continue to stir and react to obtain the organic fluorosilicon modified resin; The type B nano-silica is prepared as follows: the surface of the nano-silica is coated with silane coupling agent KH-550; The particle size of the type A nano-silica is 300-500 nm, and the particle size of the type B nano-silica is 50-100 nm.

2. The self-cleaning coating according to claim 1, characterized in that, In step S1, the liquid ratio of azobisisobutyronitrile to anhydrous ethanol is 1:1 g / ml, and the mass ratio of azobisisobutyronitrile to type A nano-silica is 1:1.

5.

3. The self-cleaning coating according to claim 1, wherein In steps S1-S2, the mass ratio of trifluoroethyl methacrylate, γ-(methacryloyloxy) propyl trimethoxysilane, butyl acrylate and azobisisobutyronitrile is 1.5:1:4:0.

15.

4. The self-cleaning coating according to claim 1, wherein In step S3, the stirring reaction temperature is controlled at 75°C, and the stirring reaction time is 2 h.

5. The self-cleaning coating according to claim 1, wherein The leveling agent is polymethyl acrylate, the defoaming agent is polydimethylsiloxane, and the solvent is dimethylbenzene.

6. The method of claim 1-5, wherein the self-cleaning coating is prepared by a method comprising: The following steps are included: (1) add the solvent, leveling agent and defoaming agent to a dispersing machine, then add the organic fluorosilicon modified resin and mix well to obtain a mixture; (2) add the type B nano-silica to the mixture, stir until uniform, and obtain the self-cleaning paint.

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