Preparation method of multifunctional coating with corrosion resistance, high temperature resistance and aging resistance

Abstract

The invention relates to the technical field of functional coatings, in particular to a preparation method of an anti-corrosion, high-temperature-resistant and aging-resistant multifunctional coating, which comprises preparation of an organic silicon modified coating and an anti-corrosion, high-temperature-resistant and aging-resistant coating. According to the invention, the silane coupling agent is modified and then is subjected to co-hydrolysis with the organic metal salt to prepare the high-performance coating of organic polymer chain-bridged inorganic nanoparticles, and the selected long-chain organic silicon is used for modifying different silane coupling agents to improve the toughness and hydrophobicity of the coating; the adhesion and corrosion resistance of the coating are improved by introducing epoxy and dopamine structures, and the ageing resistance is improved by the nano particle effect of nano silicon dioxide and metal oxide. The coating integrating multiple functions is prepared through co-hydrolysis of organic silicon and organic metal salt, the defect that multiple functions of an existing coating cannot be considered at the same time is overcome, and the coating has important significance for widening the practical application of the coating.

Description

Technical Field

[0001] The present invention belongs to the technical field of coating preparation, and particularly relates to a preparation method of a multifunctional coating with anti-corrosion, high temperature resistance and aging resistance. Background Art

[0002] In the current era of the rapid development of aerospace, aviation, and navigation industries, the coatings on the surface of the airframe or hull play a crucial role. It not only has to protect the internal materials from various challenges in the complex and harsh external environment such as seawater erosion, high-temperature burning, low-temperature freezing, and strong ultraviolet radiation, but also has to take into account the aesthetic and cleanliness requirements in appearance to meet the strict usage standards in various fields.

[0003] At present, the mainstream coating preparation technologies mainly focus on organic coatings and organic-inorganic composite coatings. However, both of them have obvious drawbacks. For organic coatings, although they have certain advantages in flexibility and chemical stability, and can adapt to material deformation to a certain extent and resist the erosion of some chemical substances, their heat resistance and aging resistance are poor. This means that in high-temperature working conditions or during long-term use, the coatings are prone to problems such as aging and peeling, greatly shortening their protection validity period and unable to provide long-term and reliable protection for the airframe and hull. The preparation of organic-inorganic composite coatings attempts to make up for the shortcomings of organic coatings. Although it has successfully improved the heat resistance and aging resistance of the materials, new problems have been introduced. On the one hand, it is difficult to ensure the uniform distribution of fillers in the composite system, and agglomeration is likely to occur, resulting in uneven local properties of the coatings and leaving hidden dangers for the overall protection effect. On the other hand, it is extremely difficult to achieve an ideal interaction between the fillers and the polymer. Often, a large amount of energy is required for complex filler structure design and chemical modification operations, and specific functional goals such as hydrophobicity, anti-icing property, high temperature resistance, anti-aging property, adhesion, and salt spray resistance can only be achieved after going through cumbersome steps. Such a complex preparation process is not only inefficient but also greatly increases the production cost and R & D cycle, seriously restricting the large-scale application and promotion of high-performance coatings.

[0004] Facing these dilemmas, the sol-gel method shows unique potential. It cleverly converts organic components into inorganic components through hydrolysis and condensation reactions, opening up a new way to improve the heat resistance and aging resistance of materials. Moreover, by precisely controlling the formula, the size of the final nanoparticles can be effectively controlled, and many special effects of nanoparticles, such as surface and interface effects, small size effects, quantum size effects, and macroscopic quantum tunneling effects, can be fully utilized. Theoretically, it provides the possibility to achieve the integration of coating multifunctions and is expected to solve the problems of single function or cumbersome preparation of existing coatings. However, at present, the sol-gel method is still not mature in coating preparation applications, and there is no complete, simple and efficient implementation plan that can fully play its advantages and effectively meet the urgent needs of high-performance and multifunctional integrated coatings in fields such as aerospace, aviation, and navigation.

[0005] In summary, there is an urgent need for a coating preparation method that can simply and efficiently prepare a coating integrating multiple excellent functions. Summary of the Invention

[0006] In view of this, the present invention aims to provide a preparation method for a multifunctional coating with anti-corrosion, high temperature resistance and aging resistance. This method uses the sol-gel method to co-hydrolyze a modified silane coupling agent and an organometallic salt. By optimizing the formulation and preparation process, a coating with polymer chain bridging different sizes and different types of inorganic nanoparticles can be simply and efficiently prepared, laying a solid foundation for the preparation of coatings in subsequent different application fields.

[0007] To achieve the above object, the present invention adopts the following technical solutions.

[0008] A preparation method for a multifunctional coating with anti-corrosion, high temperature resistance and aging resistance, which comprises the following steps:

[0009] S1: Preparation of a modified silane coupling agent

[0010] Add a monomer containing an epoxy functional group and a silane coupling agent to an organic solvent, and react in the presence of an organic base catalyst to obtain an epoxy-modified silane coupling agent, wherein the molar ratio of the epoxy functional group to the amino group or mercapto group in the silane coupling agent is (7-5):(3-5), the mass ratio of the monomer containing an epoxy functional group to the organic solvent is 10%-30%, and the mass ratio of the catalyst to the monomer containing an epoxy functional group is 0.001:1;

[0011] S2: Add the epoxy-modified silane coupling agent, the silane coupling agent with a fluorine chain and the organometallic salt obtained in step S1 to a mixed solvent in a mass ratio of (5-9):(0.1-1):(1-4), and react for a certain time under the action of an acid or base catalyst to carry out co-hydrolysis to obtain a sol, and coat the sol on the surface of the substrate to prepare the target functional coating.

[0012] Further, the organic solvent in step S1 includes but is not limited to N,N-dimethylformamide, N,N-dimethylacetamide, dichloromethane, chloroform, tetrahydrofuran, dioxane, pyridine or toluene, or any combination thereof.

[0013] Further, the monomer containing an epoxy functional group is any one or a combination of diglycidyl 4,5-epoxytetrahydrophthalate, glycidyl ether of p-aminophenol, trifunctional glycidylamine epoxy resin, N,N,N',N'-tetraglycidyl-4,4'-diaminodiphenylmethane, isocyanuric acid triglycidyl ester, neopentyl glycol diglycidyl ether, glycerol diglycidyl ether, pentaerythritol glycidyl ether and trimethylolpropane glycidyl ether.

[0014] Further, the silane coupling agent is any one or a combination thereof selected from 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-(2,3-epoxypropoxypropyl)trimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, vinyltris(2-methoxyethoxy)silane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, 3-isocyanatopropyltriethoxysilane, 3-isocyanatopropyltrimethoxysilane, methyl orthosilicate, ethyl orthosilicate, and propyl orthosilicate.

[0015] Further, the organosilicon containing diamine is any one or a combination thereof selected from 1,3-bis(3-aminopropyl)tetramethyldisiloxane and bis(3-aminopropyl)-terminated poly(dimethylsiloxane) with different molecular weights.

[0016] Further, the fluorinated silane coupling agent is any one or a combination thereof selected from heptadecafluorodecyltrimethoxysilane, heptadecafluorodecyltriethoxysilane, tridecafluorooctyltrimethoxysilane, and tridecafluorooctyltriethoxysilane.

[0017] Further, the organometallic salt is any one or a combination thereof selected from tetrabutyl titanate, tetrabutyl zirconate, zinc acetylacetonate, zinc ethyl acetoacetate, magnesium acetylacetonate, and aluminum acetylacetonate.

[0018] Further, in step S2, the mixed solvent is a mixture of water and any one or a combination thereof selected from N,N-dimethylformamide, N,N-dimethylacetamide, acetonitrile, methanol, ethanol, isopropanol, ethylene glycol, n-butanol, acetone, and methyl ethyl ketone. Preferably, water accounts for 5% to 20% in the mixed solvent.

[0019] Further, the acid or base catalyst in step S2 is an inorganic acid, an organic acid, an organic base, or an inorganic base.

[0020] Further, the inorganic acid is trifluoroacetic acid, hydrochloric acid, or sulfuric acid; the organic acid is glacial acetic acid or p-toluenesulfonic acid; the organic base is triethylamine, ethylenediamine, tetramethylammonium hydroxide, or tetraethylammonium hydroxide; and the inorganic base is sodium hydroxide or potassium hydroxide.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] The present invention provides a method for preparing a modified silane coupling agent and a method for preparing an anti-corrosion, high-temperature resistant, and aging-resistant coating by sol-gel method. This method is different from the previous method of preparing a composite coating by blending a polymer and an inorganic filler. The above method is to prepare a coating with polymer chain-bridged inorganic nanoparticles by co-hydrolyzing a modified silane coupling agent and an organometallic salt. The process is simple, and the overall structure is uniform and stable, avoiding the problems of insufficient filler distribution uniformity and organic-inorganic interaction force in the previous composite materials. This preparation strategy has simple and efficient operation steps, and the coating function is easy to control, providing a new strategy for coating preparation and facilitating industrial production applications.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] 1) The present invention realizes the preparation of an organic-inorganic hybrid coating through the modification of a silane coupling agent and its co-hydrolysis with an organometallic salt. The whole preparation process is simple and easy for batch production.

[0025] 2) In the coating prepared by the present invention, the nanoparticles are bridged together by polymer chains, forming a coating with a uniform and stable structure, avoiding the deficiency of non-uniform structure in the composite coating.

[0026] 3) The size of the nanoparticles in the present invention is easy to control. By utilizing the differences in the properties of nanoparticles with different sizes, the coating is endowed with various functions, such as anti-corrosion, high-temperature resistance, anti-aging, hydrophobicity, anti-icing, adhesion, and salt spray resistance. The performance of the prepared coating shows no obvious change after salt spray test and anti-aging test under national standard conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 The schematic diagram showing the hydrophobic property of the coating prepared in the embodiment of the present invention.

[0028] Figure 2 The comparison diagram showing the coating prepared in the embodiment of the present invention before and after high-temperature treatment.

[0029] Figure 3 The schematic diagram showing the anti-icing property of the coating prepared in the embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0030] Hereinafter, the technical solutions in the present invention will be clearly and completely described in conjunction with the embodiments and the accompanying drawings in the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0031] Example 1

[0032] Add N,N-dimethylformamide, diglycidyl 4,5-epoxytetrahydrophthalate, 3-aminopropyltrimethoxysilane and triethylamine into a container equipped with a magnetic stirrer in sequence. The molar ratio of epoxy functional groups to amino groups in the silane coupling agent is 2:1, and the mass ratio of monomer to solvent is 0.2. The mass ratio of catalyst to monomer is 0.001. After reacting at 50 °C for 12 h, an epoxy-modified silane coupling agent is obtained. Add the modified silane coupling agent, a silane coupling agent with a fluorine chain, tetrabutyl zirconate and an organic base catalyst into an aqueous solution of N,N-dimethylformamide simultaneously according to a molar ratio of 1:1:0.001. After reacting under magnetic stirring for 2 h, the obtained gel is coated to prepare the target functional coating.

[0033] Example 2

[0034] Add N,N-dimethylacetamide, p-aminophenol glycidyl ether trifunctional glycidylamine epoxy resin, 3-aminopropyltriethoxysilane and ethylenediamine into a container equipped with a magnetic stirrer in sequence. The molar ratio of epoxy functional groups to amino groups in the silane coupling agent is 2:1, and the mass ratio of monomer to solvent is 0.2. The mass ratio of catalyst to monomer is 0.001. After reacting at 50 °C for 12 h, an epoxy-modified silane coupling agent is obtained. Add the modified silane coupling agent, tetrabutyl zirconate and an acid catalyst into an aqueous solution of N,N-dimethylacetamide simultaneously according to a molar ratio of 1:1:0.001. After reacting under magnetic stirring for 2 h, the obtained gel is coated to prepare the target functional coating.

[0035] Example 3

[0036] Add dichloromethane, N,N,N',N'-tetraglycidyl-4,4'-diaminodiphenylmethane, 3-(2,3-epoxypropoxypropyl)trimethoxysilane and tetramethylammonium hydroxide into a container equipped with a magnetic stirrer in sequence. The molar ratio of epoxy functional groups to amino groups in the silane coupling agent is 1:1, and the mass ratio of monomer to solvent is 0.2. The mass ratio of catalyst to monomer is 0.001. After reacting at 50 °C for 12 h, an epoxy-modified silane coupling agent is obtained. Add the modified silane coupling agent, tetrabutyl zirconate and an organic base catalyst into an acetonitrile solution simultaneously according to a molar ratio of 1:1:0.001. After reacting under magnetic stirring for 2 h, the obtained gel is coated to prepare the target functional coating.

[0037] Example 4

[0038] N,N-dimethylformamide, triglycidyl isocyanurate, 3-mercaptopropyltriethoxysilane, and tetraethylammonium hydroxide were successively added to a container equipped with a magnetic stirrer. The molar ratio of epoxy functional groups to amino groups in the silane coupling agent was 1:1, the mass ratio of monomer to solvent was 0.2, and the mass ratio of catalyst to monomer was 0.001. After reacting at 50 °C for 12 h, an epoxy-modified silane coupling agent was obtained. The modified silane coupling agent, tetrabutyl zirconate, and acid catalyst were simultaneously added to methanol in a molar ratio of 1:1:0.001. After reacting under magnetic stirring for 2 h, the resulting gel was coated to prepare the target functional coating.

[0039] Example 5

[0040] Tetrahydrofuran, neopentyl glycol diglycidyl ether, 3-mercaptopropyltrimethoxysilane, and tetraethylammonium hydroxide were successively added to a container equipped with a magnetic stirrer. The molar ratio of epoxy functional groups to amino groups in the silane coupling agent was 1:1, the mass ratio of monomer to solvent was 0.2, and the mass ratio of catalyst to monomer was 0.001. After reacting at 50 °C for 12 h, an epoxy-modified silane coupling agent was obtained. The modified silane coupling agent, tetrabutyl titanate, and organic base catalyst were simultaneously added to methanol in a molar ratio of 1:1:0.001. After reacting under magnetic stirring for 2 h, the resulting gel was coated to prepare the target functional coating.

[0041] Example 6

[0042] Chloroform, glycerol diglycidyl ether, vinyltris(2-methoxyethoxy)silane, and tetraethylammonium hydroxide were successively added to a container equipped with a magnetic stirrer. The molar ratio of epoxy functional groups to amino groups in the silane coupling agent was 1:1, the mass ratio of monomer to solvent was 0.2, and the mass ratio of catalyst to monomer was 0.001. After reacting at 50 °C for 12 h, an epoxy-modified silane coupling agent was obtained. The modified silane coupling agent, tetrabutyl titanate, and acid catalyst were simultaneously added to an acetone solution in a molar ratio of 1:1:0.001. After reacting under magnetic stirring for 2 h, the resulting gel was coated to prepare the target functional coating.

[0043] Example 7

[0044] N,N-dimethylacetamide, pentaerythritol glycidyl ether, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane and tetraethylammonium hydroxide were added to a container equipped with a magnetic stirrer in sequence, wherein the molar ratio of the epoxy functional group to the amino group in the silane coupling agent was 1:1, and the mass ratio of the monomer to the solvent was 0.2. The mass ratio of the catalyst to the monomer was 0.001. After reacting at 50°C for 12 hours, an epoxy-modified silane coupling agent was obtained. The modified silane coupling agent, zinc acetylacetonate and an acid catalyst were added to the acetone solution at a molar ratio of 1:1:0.001 at the same time, and after reacting for 2 hours under magnetic stirring, the obtained gel was coated to prepare a functional coating.

[0045] Example 8

[0046] Dichloromethane, hydroxymethylpropane glycidyl ether, 3-isocyanatepropyl triethoxysilane and triethylamine were added to a container equipped with a magnetic stirrer in sequence, wherein the molar ratio of the epoxy functional group to the amino group in the silane coupling agent was 1:1, and the mass ratio of the monomer to the solvent was 0.2. The mass ratio of the catalyst to the monomer was 0.001. After reacting at 50°C for 12 hours, an epoxy-modified silane coupling agent was obtained. The modified silane coupling agent, ethyl acetoacetate zinc and an alkali catalyst were added simultaneously to an aqueous solution of N,N-dimethylformamide in a molar ratio of 1:1:0.001, reacted for 2 hours under magnetic stirring, and the obtained gel was coated to prepare a functional coating.

[0047] Example 9

[0048] N,N-dimethylformamide, 4,5-epoxytetrahydrophthalic acid diglycidyl ester, 3-isocyanatepropyltrimethoxysilane and triethylamine were added to a container equipped with a magnetic stirrer in sequence, wherein the molar ratio of epoxy functional group to amino group in silane coupling agent was 1:1, and the mass ratio of monomer to solvent was 0.2. The mass ratio of catalyst to monomer was 0.001. After reacting at 50°C for 12 hours, an epoxy-modified silane coupling agent was obtained. The modified silane coupling agent, magnesium acetylacetonate and alkaline catalyst were added to the N,N-dimethylformamide aqueous solution at a molar ratio of 1:1:0.001 at the same time, and after reacting for 2 hours under magnetic stirring, the obtained gel was coated to prepare a functional coating.

[0049] Example 10

[0050] N,N-dimethylacetamide, triglycidylamine epoxy resin of p-aminophenol glycidyl ether, methyl orthosilicate and triethylamine were successively added into a container equipped with a magnetic stirrer. The molar ratio of epoxy functional groups to amino groups in the silane coupling agent was 1:1, the mass ratio of monomer to solvent was 0.2, and the mass ratio of catalyst to monomer was 0.001. After reacting at 50 °C for 12 h, an epoxy-modified silane coupling agent was obtained. The modified silane coupling agent, silane coupling agent with fluorine chain, aluminum acetylacetonate, zinc acetylacetonate, tetrabutyl titanate and base catalyst were simultaneously added into an aqueous N,N-dimethylformamide solution according to the molar ratio of silane coupling agent, organometallic salt and catalyst of 1:1:0.001. After reacting under magnetic stirring for 2 h, the obtained gel was coated to prepare a functional coating.

[0051] The anti-corrosion, high-temperature resistant and aging-resistant coatings obtained in Examples 1 to 10 were subjected to an acidic atmosphere test according to GJB 150.28-2009. After the test, there was no obvious corrosion on the coating surface; tested according to the neutral salt spray test of GJB 150.11A-2009, there was no corrosion on the coating surface after the test; tested according to the mold resistance test of GJB 150.10A-2009, there was no obvious mold attachment on the coating surface after the test, which was grade 0. After 1000 h of ultraviolet accelerated aging, the contact angle of the coating remained above 100°. After the coating was calcined at 500 °C for 2 h, the surface properties did not change significantly, and the contact angle of the coating remained above 100°. Figures 1 to 3 The schematic diagrams of the hydrophobic property, high-temperature resistance property and anti-icing property of the coatings prepared in the examples of the present invention are respectively shown.

[0052] It should be noted that the above-mentioned embodiments are only the preferred embodiments of the present invention. For those of ordinary skill in the art, without departing from the principle of the present invention, several modifications, improvements and equivalent replacements can be made to the present invention, and these modifications, improvements and equivalent replacements are also regarded as falling within the protection scope of the claims of the present invention.

Claims

1. A method for preparing a multifunctional coating that is corrosion-resistant, high-temperature-resistant and aging-resistant, characterized in that: The steps include: S1: Preparation of modified silane coupling agent Adding a monomer containing an epoxy functional group and a silane coupling agent into an organic solvent and reacting them in the presence of an organic base catalyst to obtain an epoxy-modified silane coupling agent, wherein the molar ratio of the epoxy functional group to the amino group or the mercapto group in the silane coupling agent is (7-5):(3-5), the mass ratio of the monomer containing the epoxy functional group to the organic solvent is 10%-30%, and the mass ratio of the catalyst to the monomer containing the epoxy functional group is 0.001:1; S2: adding the epoxy-modified silane coupling agent, the silane coupling agent with a fluorine chain and the organic metal salt obtained in step S1 into a mixed solvent in a mass ratio of (5-9):(0.1-1):(1-4), reacting for a certain period of time under the action of an acid or base catalyst to perform co-hydrolysis to obtain a sol, and applying the sol to the surface of the substrate to prepare a target functional coating.

2. The method for preparing the anti-corrosion, high temperature and aging resistant multifunctional coating according to claim 1, characterized in that: The organic solvent in step S1 includes, but is not limited to, N,N-dimethylformamide, N,N-dimethylacetamide, dichloromethane, chloroform, tetrahydrofuran, dioxane, pyridine or toluene, or any combination thereof.

3. The method for preparing the anti-corrosion, high temperature and aging resistant multifunctional coating according to claim 1, characterized in that: The monomer containing epoxy functional groups is any one of 4,5-epoxytetrahydrophthalic acid diglycidyl ester, p-aminophenol glycidyl ether trifunctional glycidyl amine epoxy resin, N,N,N',N'-tetraepoxypropyl-4,4'-diaminodiphenylmethane, isocyanuric acid triglycidyl ester, neopentyl glycol diglycidyl ether, glycerol diglycidyl ether, pentaerythritol glycidyl ether and hydroxymethylpropane glycidyl ether or a combination thereof.

4. The method for preparing the anti-corrosion, high temperature and aging resistant multifunctional coating according to claim 1, characterized in that: The silane coupling agent is any one of 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-(2,3-epoxypropyl)trimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, vinyltri(2-methoxyethoxy)silane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, 3-isocyanatepropyltriethoxysilane, 3-isocyanatepropyltrimethoxysilane, methyl orthosilicate, ethyl orthosilicate and propyl orthosilicate, or a combination thereof.

5. The method for preparing the anti-corrosion, high temperature and aging resistant multifunctional coating according to claim 1, characterized in that: The diamine-containing organosilicon is any one of 1,3-bis(3-aminopropyl)tetramethyldisiloxane and bis(3-aminopropyl)-terminated poly(dimethylsiloxane) of different molecular weights or a combination thereof.

6. The method for preparing the anti-corrosion, high temperature and aging resistant multifunctional coating according to claim 1, characterized in that: The fluorine-containing silane coupling agent is any one of heptadecafluorodecyltrimethoxysilane, heptadecafluorodecyltriethoxysilane, tridecafluorooctyltrimethoxysilane and tridecafluorooctyltriethoxysilane or a combination thereof.

7. The method for preparing the anticorrosion, high temperature and aging resistant multifunctional coating according to claim 1, characterized in that: The organic metal salt is any one of tetrabutyl titanate, tetrabutyl zirconate, zinc acetylacetonate, ethyl zinc acetylacetonate, magnesium acetylacetonate and aluminum acetylacetonate or a combination thereof.

8. The method for preparing the anti-corrosion, high temperature and aging resistant multifunctional coating according to claim 1, characterized in that: In step S2, the mixed solvent is a mixture of water and any one of N,N-dimethylformamide, N,N-dimethylacetamide, acetonitrile, methanol, ethanol, isopropanol, ethylene glycol, n-butanol, acetone and butanone, or a combination thereof.

9. The method for preparing the anti-corrosion, high temperature and aging resistant multifunctional coating according to claim 1, characterized in that: The acid or base catalyst described in step S2 is an inorganic acid, an organic acid, an organic base or an inorganic base.

10. The method for preparing the anti-corrosion, high temperature and aging resistant multifunctional coating according to claim 9, characterized in that: The inorganic acid is trifluoroacetic acid, hydrochloric acid or sulfuric acid; the organic acid is glacial acetic acid or p-toluenesulfonic acid; the organic base is triethylamine, ethylenediamine, tetramethylammonium hydroxide or tetraethylammonium hydroxide; the inorganic base is sodium hydroxide or potassium hydroxide.

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