High-adhesion high-temperature-resistant synergistic curing resin, preparation method thereof and preparation method of anticorrosive coating of high-adhesion high-temperature-resistant synergistic curing resin

Abstract

The invention belongs to the field of metal high-temperature resistance and corrosion prevention, and particularly relates to high-adhesion high-temperature-resistant synergistic curing resin, a preparation method and a preparation method of an anticorrosive coating of the resin. The high-adhesion high-temperature-resistant synergistic curing resin is prepared from cyano resin, epoxy resin and a silane coupling agent, the mass ratio of the epoxy resin to the cyano resin is 1: (1-3), and the adding amount of the silane coupling agent accounts for 1%-3% of the mass fraction of all the resin raw materials. The coating disclosed by the invention is high in interface bonding strength with a matrix, and a coating layer has relatively good adhesion capacity and can be kept not to fall off or gelatinize for more than 300 hours in an acid-base environment of 180 DEG C. The method is high in technological operability, mild in reaction condition, low in cost and environmentally friendly, the problem that a current metal protective coating is prone to falling off and gelatinizing at high temperature can be solved, and potential industrial production application value is achieved.

Description

Technical Field

[0001] This invention belongs to the field of high-temperature corrosion resistance of metals, and particularly relates to a high-adhesion, high-temperature synergistic curing resin, its preparation method, and its anti-corrosion coating preparation method. Background Technology

[0002] Metallic materials, as commonly used engineering materials, play an indispensable role in fields such as machinery manufacturing, aerospace, construction, civil engineering, and chemical engineering. However, metal corrosion is prevalent in industrial production. If metal corrosion is not prevented and controlled, it will not only cause huge losses to the economy and society but also lead to serious pollution problems and even various catastrophic accidents. According to research data from the National Association of Corrosion Engineers (NACE), the annual losses caused by metal corrosion worldwide can reach US$2.5 trillion, accounting for approximately 3.4% of global GDP. Effective methods to inhibit or delay metal corrosion can reduce this amount by 15%-35%, thereby saving approximately US$375-875 billion. Anti-corrosion coatings, with their convenient application and excellent anti-corrosion performance, are widely used in the field of metal corrosion protection.

[0003] The main anti-corrosion mechanisms include shielding and isolation, passivation and corrosion inhibition, and electrochemical protection. Shielding and isolation is a simple and common anti-corrosion method. Applying an anti-corrosion coating with a shielding effect to a metal material can effectively isolate the corrosive medium from the protected metal, thus protecting the metal material from corrosion. The base resin of the coating needs to be selected with good mechanical properties and uniform film formation to form a stable coating and obtain better anti-corrosion effect. The resin, after being cross-linked and cured by adding a curing agent, has strong cohesion, excellent mechanical properties, excellent adhesion, and excellent chemical stability. It can be widely used as a coating for the anti-corrosion of metal materials and can solve corrosion problems in the field of materials. Generally, anti-corrosion thermosetting resins choose epoxy resins, which are relatively inexpensive and have high adhesion. However, due to the disadvantages such as high internal stress and brittleness after curing, its fracture toughness is low, making it more sensitive to microcracks and limiting its further application. By uniformly dispersing inorganic fillers in an epoxy resin system, the resin forms a continuous phase while the inorganic fillers act as the dispersed phase, creating an "island structure." This significantly improves the toughness of the cured system, thus providing a toughening effect. Furthermore, epoxy resin undergoes molecular chain breakage at high temperatures, leading to gelatinization and deterioration, and loss of its anti-corrosion properties. Cyano resins are a new type of resin containing nitrogen-containing heterocyclic cross-linked structures. They can withstand instantaneous temperatures exceeding 400℃ and possess excellent mechanical properties, but they suffer from high curing temperatures and insufficient adhesion. Therefore, research on the application of cyano resins as anti-corrosion coatings is rarely reported. Summary of the Invention

[0004] The purpose of this invention is to provide a high-adhesion, high-temperature resistant, synergistically curing resin, its preparation method, and a method for preparing an anti-corrosion coating. While retaining the high-temperature resistance of cyano resin, epoxy resin is introduced to improve its processability and adhesion. Simultaneously, the hydroxyl groups formed during the pre-curing process of the epoxy resin can synergistically catalyze a high-temperature cyanolation reaction for cross-linking and curing. This eliminates the need for post-curing agents, reducing process steps and costs. The coating can be stored at room temperature for extended periods. Furthermore, the addition of an inorganic ceramizable reinforcing agent allows for the formation of a ceramicized protective layer at high temperatures, improving the coating's thermo-oxidative protection performance.

[0005] To achieve the above objectives, the present invention employs the following technical solution:

[0006] A high-adhesion, high-temperature resistant, synergistically curing resin is prepared from raw materials including cyano resin, epoxy resin, and silane coupling agent. The mass ratio of epoxy resin to cyano resin is 1:(1-3), and the amount of silane coupling agent added accounts for 1% to 3% of the total mass fraction of the resin raw materials.

[0007] Furthermore, the silane coupling agent is one of KH550, KH560, KH570, TESPT, and VTES; the epoxy resin is a bisphenol A type epoxy resin.

[0008] A method for preparing a high-adhesion, high-temperature resistant, synergistically curing resin includes the following steps:

[0009] 1) Dissolve cyano resin and epoxy resin in an organic solvent, heat and stir until uniformly mixed, and the heating temperature is 60-80℃.

[0010] 2) Add a silane coupling agent to the composite resin obtained in step 1) at a temperature of 60–80°C and mix. The silane coupling agent undergoes a chemical cross-linking reaction with the hydroxyl groups in the resin to form a stable hydrogen bond network; simultaneously, the nitrogen atoms on the coupling agent can chelate with the metal surface, thus firmly adhering to the metal surface. This dual action significantly improves the adhesion of the coating. The high-adhesion, high-temperature resistant, synergistically cured resin achieves an adhesion level as high as 0, and the resin does not gelatinize or fail at high temperatures.

[0011] The cyano resin used in this invention is derived from the existing patent ZL202111663564.X, entitled "A low-melting-point self-catalytic curing resin oligomer, cured product and preparation method thereof".

[0012] Furthermore, the organic solvent is one or more mixed solvents selected from DMSO, DMAc, DMF, and NMP.

[0013] A method for preparing a high-adhesion, high-temperature resistant, synergistically curing resin anti-corrosion coating specifically includes the following steps:

[0014] 1) Add high-adhesion, high-temperature resistant, synergistic curing resin, filler, and dispersant to a flask, heat and stir at 60-80°C, then add leveling agent, stir evenly, stop heating, cool to room temperature, add defoamer and accelerator, stir evenly, let stand to defoam, discharge, and obtain high-adhesion, high-temperature resistant, synergistic curing resin anti-corrosion coating.

[0015] 2) Apply the high-adhesion, high-temperature resistant, synergistic curing resin anti-corrosion coating obtained in step 1) to the metal surface and perform two-stage curing. The pre-curing temperature is 120-150℃ and the time is 0.5-2h; the high-temperature curing temperature is 180-230℃ and the time is 1-5h to obtain a high-temperature resistant anti-corrosion coating.

[0016] Furthermore, the filler is one or more of graphite, ceramic powder, glass powder, talc powder, wollastonite, Si3N4, TiO2, SiC, SiO2 and Al2O3, and the amount of filler added is 5% to 75% of the total mass fraction of cyano resin and epoxy resin.

[0017] Furthermore, the dispersant is one or more of PVP, PEG, PVA, PAA and SDS, and the amount of the dispersant added is 1% to 2.5% of the total mass fraction of cyano resin and epoxy resin.

[0018] Furthermore, the leveling agent is one of AG-105, AG-108, AG-120, AG-195, BYK-333, BYK-354, BYK-358N, and BYK-370, and the defoamer is one of FAG470, GP330, and SXP-107-1. The addition amount of the leveling agent and the defoamer is 0.3% to 1.5% of the total mass fraction of cyano resin and epoxy resin.

[0019] Furthermore, the accelerator is one of o-hydroxybenzyl dimethylamine, 2,4,6-tris(dimethylaminomethyl)phenol, N,N-dimethylbenzylamine, and ethanolamine, and the amount of accelerator added is 1% to 5% of the total mass fraction of cyano resin and epoxy resin.

[0020] The high-adhesion, high-temperature resistant, synergistically cured resin anti-corrosion coating has a thickness of 20–100 μm; the coating adhesion is grade 0–2; and after 350 hours of acid and alkali resistance testing at 180°C, no cracking, peeling, or flaking was observed, and no corrosion was observed.

[0021] Compared with existing technologies, the beneficial effects of this invention are:

[0022] The resin-based anti-corrosion coating prepared by this invention can be stored at room temperature, and the curing process can be initiated by raising the temperature as needed. The addition of an epoxy accelerator generates hydroxyl groups during the high-temperature catalytic ring-opening polymerization of epoxy, simultaneously catalyzing the cross-linking and curing of cyano groups, giving the resin high-temperature synergistic curing properties. The hydroxyl groups during the epoxy resin ring-opening process synergistically catalyze the formation of a heterocyclic cross-linking network of cyano groups, eliminating the need for additional curing agents. After curing, the coating exhibits high-temperature corrosion resistance. The added silane coupling agent, while cross-linking with the modified composite resin, also chelates with the metal surface, enhancing the interfacial bonding strength between the coating and the substrate. The coating has good adhesion and can remain in an acidic or alkaline environment at 180℃ for over 300 hours without peeling or gelatinizing. The invented process is highly operable, has mild reaction conditions, low cost, and is environmentally friendly, solving the current problems of high-temperature peeling and gelatinization of metal protective coatings, and has potential value for industrial production applications.

[0023] The high-adhesion, high-temperature resistant, synergistic curing resin anti-corrosion coating prepared by this invention has a thickness of 20-100 μm; the coating adhesion is grade 0-2; and no cracking, peeling, or flaking or corrosion was observed during a 300-hour acid and alkali resistance test at 180℃. Attached Figure Description

[0024] Figure 1 This is a macroscopic view of the resin coating obtained in Embodiment 1 of the present invention.

[0025] Figure 2 This is a cross-cut test pattern of the resin coating prepared in Embodiment 1 of the present invention.

[0026] Figure 3 This is a macroscopic view of the resin coating obtained in Embodiment 2 of the present invention.

[0027] Figure 4 This is a cross-cut adhesion test pattern of the resin coating obtained in Example 2 of the present invention.

[0028] Figure 5 This is a macroscopic view of the resin coating obtained in Embodiment 3 of the present invention.

[0029] Figure 6 This is a cross-cut adhesion test pattern of the resin coating obtained in Embodiment 3 of the present invention. Detailed Implementation

[0030] The present invention is further illustrated below by way of embodiments, but these embodiments are not intended to limit the invention to the scope of the embodiments described. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0031] This invention uses epoxy-modified cyano resin as the matrix and inorganic non-metallic or metal oxides as reinforcements to synergistically cure the resin-based coating material. The resulting coating has a dense and smooth surface, high adhesion, and high-temperature resistance. The production process of this invention is highly operable, has mild reaction conditions, low cost, and is environmentally friendly. The prepared resin coating can meet the requirements for high-temperature corrosion protection of metal surfaces. See the following examples for details.

[0032] Example 1:

[0033] 50 g of cyano resin and 25 g of E51 were placed in 150 ml of NMP solvent and heated and stirred at 70°C for 2 h. Then, 1.2 g of KH550 was added, and stirring was continued for 1 h to obtain a homogeneous and stable composite resin solution. 15 g of graphite, 1 g of PEG, and 0.5 g of BYK-333 were added to the composite resin in sequence. The mixture was heated and stirred at 70°C for 1 h, then the heating was turned off, and stirring was continued until room temperature. Then, 0.5 g of FAG470 and 2.5 g of 2,4,6-tris(dimethylaminomethyl)phenol were added, and the mixture was stirred for 1 h and allowed to stand for 1 h to obtain a high-adhesion, high-temperature resistant, synergistically curing resin anticorrosive coating. The anticorrosive coating was applied to the metal surface by brushing, and the temperature was increased to 120°C and held for 1 h to complete the curing and form a coating. The final resin coating is shown in the figure below. Figure 1 As shown, the 100-square test is as follows Figure 2 As shown, the coating performance results are shown in Table 1.

[0034] Example 2:

[0035] 50 g of cyano resin and 25 g of E44 were placed in 200 ml of DMSO solvent and heated and stirred at 80°C for 1 h. Then, 1.5 g of KH560 was added, and stirring was continued for 1 h to obtain a homogeneous and stable composite resin solution. 35 g of SiC, 1.5 g of PVP, and 0.5 g of AG-105 were added to the composite resin sequentially, and stirred for 2 h. After heating was turned off, stirring was continued until room temperature. Then, 0.75 g of FAG470 and 3.5 g of ethanolamine were added, and stirring was carried out for 0.5 h. After standing for 1 h, a high-adhesion, high-temperature resistant, synergistically curing resin anticorrosive coating was obtained. The anticorrosive coating was applied to the metal surface by roller coating, and the temperature was increased to 125°C and held for 1 h. The temperature was then increased to 190°C and held for 1.5 h to complete the curing and form a coating. The final resin coating is shown in the figure below. Figure 3 As shown, the 100-square test is as follows Figure 4 As shown, the coating performance results are shown in Table 1.

[0036] Example 3:

[0037] 50 g of cyano resin and 50 g of E51 were placed in 200 ml of DMAc solvent and heated and stirred at 70°C for 1 h. Then, 2 g of KH550 was added, and stirring was continued for 1 h to obtain a homogeneous and stable composite resin solution. 20 g of SiO2, 1 g of PVP, and 0.5 g of AG-120 were added to the composite resin sequentially, and stirred for 2 h. After heating was turned off, stirring was continued until room temperature. Then, 0.75 g of GP330 and 3 g of N,N-dimethylbenzylamine were added, and stirring was carried out for 0.75 h. After standing for 1 h, a high-adhesion, high-temperature resistant, synergistically curing resin anticorrosive coating was prepared. The anticorrosive coating was applied to the metal surface by dip-coating, and the temperature was increased to 130°C and held for 1 h to complete curing and form a coating. The final resin coating is shown in the figure below. Figure 5 As shown, the 100-square test is as follows Figure 6 As shown, the coating performance results are shown in Table 1.

[0038] Table 1 Performance indicators of composite resins in the examples

[0039]

[0040] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, shall still fall within the scope of protection of the present invention.

Claims

1. A high adhesion high temperature resistant synergistically cured resin, characterized in that, The preparation raw materials include cyanogen-based resin, epoxy resin and silane coupling agent, the mass ratio of the epoxy resin to the cyanogen-based resin is 1: (1-3), and the silane coupling agent is added in an amount of 1%-3% of the total mass of the resin raw materials.

2. A high adhesion high temperature resistant synergistically cured resin according to claim 1, characterized in that, The silane coupling agent is one of KH550, KH560, KH570, TESPT and VTES; and the epoxy resin is bisphenol A type epoxy resin.

3. A process for the preparation of high adhesion high temperature resistant co-cured resin as claimed in claim 1 or 2, wherein the said process comprises of the steps of: The method comprises the following steps: 1) Dissolve the cyanogen-based resin and the epoxy resin in an organic solvent, and heat and stir until mixed uniformly, with the heating temperature being 60-80 DEG C; 2) Add the silane coupling agent to the composite resin obtained in step 1) at a temperature of 60-80 DEG C and mix and stir.

4. The method for preparing a high-adhesion, high-temperature resistant, synergistically curing resin according to claim 4, characterized in that, The organic solvent is one or a mixture of two or more of DMSO, DMAc, DMF and NMP.

5. A process for the preparation of high adhesion high temperature resistant synergistically cured resin anticorrosive coating as claimed in claim 1 wherein, The method comprises the following steps: 1) Put the high-adhesion high-temperature-resistant synergistic curing resin, fillers and dispersants into a flask, heat and stir, with the heating temperature being 60-80 DEG C, then add a leveling agent, stir uniformly, stop heating, cool to room temperature, then add a defoaming agent and an accelerator, stir uniformly, stand for defoaming, and discharge to obtain the high-adhesion high-temperature-resistant synergistic curing resin anticorrosive coating; 2) Apply the high-adhesion high-temperature-resistant synergistic curing resin anticorrosive coating obtained in step 1) to a metal surface, and perform two-stage curing, with the pre-curing temperature being 120-150 DEG C and the time being 0.5-2 h; The high-temperature curing temperature is 180-230 DEG C, and the time is 1-5 h.

6. The method for preparing a high-adhesion, high-temperature resistant, synergistically curing resin anti-corrosion coating according to claim 6, characterized in that, The fillers are one or more of graphite, ceramic powder, glass powder, talc powder, wollastonite, Si3N4, TiO2, SiC, SiO2 and Al2O3, and the fillers are added in an amount of 5%-75% of the total mass of the cyanogen-based resin and the epoxy resin.

7. The method for preparing a high-adhesion, high-temperature resistant, synergistically curing resin anti-corrosion coating according to claim 6, characterized in that, The dispersants are one or more of PVP, PEG, PVA, PAA and SDS, and the dispersants are added in an amount of 1%-2.5% of the total mass of the cyanogen-based resin and the epoxy resin.

8. The method for preparing a high-adhesion, high-temperature resistant, synergistically curing resin anti-corrosion coating according to claim 6, characterized in that, The leveling agent is one of AG-105, AG-108, AG-120, AG-195, BYK-333, BYK-354, BYK-358N and BYK-370, the defoaming agent is one of FAG470, GP330 and SXP-107-1, and the leveling agent and the defoaming agent are added in an amount of 0.3%-1.5% of the total mass of the cyanogen-based resin and the epoxy resin.

9. The method for preparing a high-adhesion, high-temperature resistant, synergistically curing resin anti-corrosion coating according to claim 6, characterized in that, The accelerator is one of ortho-hydroxybenzyl dimethylamine, 2,4,6-tris (dimethylaminomethyl) phenol, N, N-dimethylbenzylamine and ethanolamine, and the accelerator is added in an amount of 1%-5% of the total mass of the cyanogen-based resin and the epoxy resin.

10. The method of claim 6, wherein the method is characterized by: The high-adhesion high-temperature-resistant synergistic curing resin anticorrosive coating has a thickness of 20-100 microns, an adhesion of 0-2 grade, and no cracking, peeling, peeling and corrosion phenomenon after acid and alkali resistance test at 180 DEG C for 300 hours.

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