Corrosion-resistant composite finned tube and preparation process thereof

Abstract

The present application relates to heat exchanger technical field, specifically to a kind of corrosion-resistant composite finned tube and its preparation process.The present application obtains flame retardant with allyl bisphenol A and 4-nitro phthalonitrile as main raw material.Then with four sulfur alcohol A, four sulfur alcohol B, 1,4-butanediol diacrylate as main raw material, curing agent is obtained.Finally, with epoxy resin E20, epoxy resin E12, polyether polyol, filler, flame retardant, curing agent, defoaming agent, accelerator and photoinitiator as raw material, epoxy resin coating is obtained;The epoxy resin coating is coated to the surface of finned tube, and the finished product is obtained.The finished product obtained by the present application has good flame retardancy, corrosion resistance and mechanical properties, so it has broad application prospect.

Description

Technical Field

[0001] The invention relates to the technical field of heat exchangers, in particular to a corrosion-resistant composite fin tube and a preparation process thereof. Background Art

[0002] Finned tubes are a key component widely used in heat transfer equipment such as heat exchangers, coolers, and radiators. They hold significant value and importance in modern engineering. First, finned tubes provide efficient heat conduction and heat transfer. Their design effectively improves the efficiency of heat exchange equipment by increasing surface area and accelerating heat transfer, making them widely used in thermal management across various fields. Second, finned tubes offer excellent wind resistance. The numerous fins arranged within the tubes not only increase the heat transfer surface area but also enhance the cooling effect of the airflow on the tubes. Furthermore, their compact structure allows them to maintain high heat transfer efficiency while reducing the size and weight of equipment without significantly compromising heat transfer efficiency. However, current finned tube technology still faces challenges and pain points that need to be overcome. In industries such as the chemical industry, marine engineering, and oil exploration, finned tubes often operate under high temperatures, high pressures, and corrosive media. Corrosion under these extreme conditions can reduce the tubes' heat transfer capacity, ultimately severely impacting their performance and lifespan.

[0003] In order to overcome the defects of the prior art, the present invention provides a corrosion-resistant composite fin tube and a preparation process thereof. Summary of the Invention

[0004] The object of the present invention is to provide a corrosion-resistant composite fin tube and a preparation process thereof, so as to solve the problems in the prior art.

[0005] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0006] A preparation process for a corrosion-resistant composite finned tube comprises the following steps:

[0007] Step 1: Allyl bisphenol A, potassium carbonate and dimethyl sulfoxide are mixed, heated to 80-90°C, stirred and reacted for 5-6 hours, and then 4-nitrophthalonitrile is added and the reaction is continued for 4-6 hours. The reaction product is filtered, washed and dried to prepare a flame retardant;

[0008] Step 2: Under a nitrogen environment, tetramercaptan A, tetramercaptan B, phenothiazine and N,N-dimethylacetamide are uniformly mixed, and 1,4-butanediol diacrylate is added dropwise to react at 6-10°C for 2-3 hours. After the reaction is completed, the mixture is extracted, washed, dried, filtered, and rotary evaporated to prepare a curing agent;

[0009] Step 3: Mix epoxy resin E20, epoxy resin E12, polyether polyol, filler, flame retardant, curing agent, defoaming agent, accelerator and photoinitiator to prepare epoxy resin coating; apply the epoxy resin coating to the surface of the fin tube, dry it at 40-60°C for 20-30 minutes, and then irradiate it under ultraviolet light for 600-700 seconds, and then wash and dry it to prepare a finished product.

[0010] More optimally, in step 1, the contents of the flame retardant components are: by mass, 16-20 parts of allyl bisphenol A, 10-15 parts of potassium carbonate, 110-120 parts of dimethyl sulfoxide, and 18-20 parts of 4-nitrophthalonitrile.

[0011] More optimally, in step 2, the molar ratio of tetramercaptan A, tetramercaptan B and 1,4-butanediol diacrylate is 1:(4-5):(4-5); the molar ratio of tetramercaptan A, phenothiazine and N,N-dimethylacetamide is 1:0.02:(15-20).

[0012] More optimally, the preparation method of tetramercaptan A is as follows: pentaerythritol, mercaptopropionic acid, p-toluenesulfonic acid and toluene are mixed under a nitrogen environment, reacted at 60-80° C. until the pH remains unchanged, and then washed, dried and filtered to prepare tetramercaptan A.

[0013] More optimally, when preparing tetramercaptan A, the molar ratio of pentaerythritol, mercaptopropionic acid, p-toluenesulfonic acid and toluene is 1:(4-4.5):0.02:6.

[0014] More optimally, the preparation method of tetrathiol B is as follows: under a nitrogen environment, 1-(2-quinoxaline)-1,2,3,4-butanetetrol, mercaptopropionic acid, p-toluenesulfonic acid and toluene are mixed, reacted at 60-80°C until the pH remains unchanged, and then washed, dried and filtered to prepare tetrathiol B.

[0015] More optimally, when preparing tetrathiol B, the molar ratio of 1-(2-quinoxaline)-1,2,3,4-butanetetrol, mercaptopropionic acid, p-toluenesulfonic acid and toluene is 1:(4-5):0.02:6.

[0016] More optimally, in step four, the content of each component of the epoxy resin coating is: in parts by mass, 20-30 parts of epoxy resin E20, 20-30 parts of epoxy resin E12, 6-10 parts of polyether polyol, 10-15 parts of filler, 8-15 parts of flame retardant, 10-15 parts of curing agent, 1-2 parts of defoaming agent, 1-2 parts of accelerator, and 3-5 parts of photoinitiator.

[0017] More optimally, the accelerator is 2-ethyl-4-methylimidazole; the photoinitiator is 2-hydroxy-2-methylpropiophenone, and the filler is silicon dioxide powder.

[0018] More optimally, the material of the finned tube is any one of stainless steel and aluminum alloy.

[0019] Beneficial effects of the present invention:

[0020] The present invention prepares a flame retardant by adding allyl bisphenol A, potassium carbonate, dimethyl sulfoxide, and 4-nitrophthalonitrile. A curing agent is prepared by adding tetramercaptan A, tetramercaptan B, 1,4-butanediol diacrylate, phenothiazine, and N,N-dimethylacetamide. Finally, an epoxy resin coating is prepared using epoxy resin E20, epoxy resin E12, polyether polyol, filler, flame retardant, curing agent, defoamer, accelerator, and photoinitiator as raw materials. The epoxy resin coating is then applied to the surface of a finned tube, dried, irradiated with ultraviolet light, washed, and finally dried to obtain a finished product.

[0021] The present invention is characterized in that, in step 1, a flame retardant is prepared by adding allyl bisphenol A, potassium carbonate, dimethyl sulfoxide, and 4-nitrophthalonitrile. On the one hand, the flame retardant contains a large amount of nitrogen, a flame retardant element, which can effectively improve the flame retardancy of epoxy resin coatings. On the other hand, the flame retardant contains a large number of double bonds, which can undergo a thiol-ene click reaction with the curing agent containing thiol groups on its surface in step 3.

[0022] In step 2, a curing agent is prepared by adding tetramercaptan A, tetramercaptan B, 1,4-butanediol diacrylate, phenothiazine, and N,N-dimethylacetamide. First, tetramercaptan A and tetramercaptan B are prepared through an esterification reaction. Then, a thiol-olefin click reaction is carried out using tetramercaptan A, tetramercaptan B, and 1,4-butanediol diacrylate as the main reactants to prepare a curing agent with a hyperbranched structure. On the one hand, this hyperbranched curing agent can undergo multiple reactions with the main epoxy resin to form a highly cross-linked network structure, significantly improving the coating's hardness, wear resistance, chemical resistance, and heat resistance. Furthermore, the hyperbranched curing agent has multiple reactive functional groups, which can increase the reaction rate and cure the coating faster. This helps improve production efficiency and shorten the coating's drying and processing time. On the other hand, the hyperbranched curing agent contains a large number of thiol groups. Therefore, in step three, by adding a photoinitiator, the curing agent containing thiol groups on the surface can undergo a thiol-ene click reaction with the flame retardant containing double bonds on the surface. This reaction can fully mix the components of the epoxy resin coating, strengthen the interaction between the different components, and improve the mechanical properties, interfacial bonding strength and overall performance of the coating. In addition, the thiol-ene click reaction has the advantages of high efficiency, low temperature and solvent-free, which can ensure the fluidity of the epoxy resin coating, avoid damage to the coating itself caused by high temperature and irritating solvents, and at the same time will not cause deterioration or odor of the coating. DETAILED DESCRIPTION

[0023] The following will provide a clear and complete description of the technical solutions of the present invention in conjunction with the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of them. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0024] Source of raw materials:

[0025] The finned tube is made of stainless steel, model 316L; the defoaming agent is provided by Foshan 3F You Chemical Co., Ltd., model AKN-3386; the epoxy resin E12 is provided by Hubei Maidehao Chemical Co., Ltd., model MDH; the epoxy resin E20 is provided by Henan Chiao Trading Co., Ltd., model NPES-901; the silicon dioxide powder is provided by Qinghe Chaotai Metal Materials Co., Ltd., with a particle size of 5000 mesh; the polyether polyol is polypropylene glycol with a molecular weight of 600; in terms of mass, one portion is 1 g.

[0026] Example 1: Step 1: 16 g of allyl bisphenol A, 10 g of potassium carbonate and 110 g of dimethyl sulfoxide were mixed, and the mixture was continuously heated to 90° C. and stirred for reaction for 6 h. 18 g of 4-nitrophthalonitrile was then added and the reaction was continued for 6 h. The reaction product was filtered, washed and dried to prepare a flame retardant.

[0027] Step 2: Under a nitrogen environment, 1 mol of pentaerythritol, 4 mol of mercaptopropionic acid, 0.02 mol of p-toluenesulfonic acid and 6 mol of toluene are mixed, reacted at 80°C until the pH remains unchanged, and then washed, dried and filtered to prepare tetramercaptan A; under a nitrogen environment, 1 mol of 1-(2-quinoxaline)-1,2,3,4-butanetetrol, 4 mol of mercaptopropionic acid, 0.02 mol of p-toluenesulfonic acid and 6 mol of toluene are mixed, reacted at 80°C until the pH remains unchanged, and then washed, dried and filtered to prepare tetramercaptan B;

[0028] Step 3: Under a nitrogen environment, 1 mol of tetramercaptan A, 4 mol of tetramercaptan B, 0.02 mol of phenothiazine and 15 mol of N,N-dimethylacetamide were mixed evenly, and then 4 mol of 1,4-butanediol diacrylate was added dropwise and reacted at 10°C for 3 hours. After the reaction, the mixture was extracted, washed, dried, filtered, and rotary evaporated to prepare a curing agent;

[0029] Step 4: 20g of epoxy resin E20, 30g of epoxy resin E12, 6g of polyether polyol, 10g of silica powder, 8g of flame retardant, 10g of curing agent, 1g of defoaming agent, 1g of 2-ethyl-4-methylimidazole and 3g of 2-hydroxy-2-methylpropiophenone are mixed to prepare an epoxy resin coating; the epoxy resin coating is applied to the surface of the fin tube, and then dried at 60°C for 30min, and then irradiated under ultraviolet light for 700s, and then washed and dried to prepare a finished product.

[0030] Example 2: Step 1: 16 g of allyl bisphenol A, 10 g of potassium carbonate, and 110 g of dimethyl sulfoxide were mixed, and the mixture was continuously heated to 87° C. and stirred for reaction for 5.7 h. 18 g of 4-nitrophthalonitrile was then added, and the reaction was continued for 5.5 h. The reaction product was filtered, washed, and dried to prepare a flame retardant.

[0031] Step 2: Under a nitrogen environment, 1 mol of pentaerythritol, 4 mol of mercaptopropionic acid, 0.02 mol of p-toluenesulfonic acid and 6 mol of toluene are mixed, reacted at 75° C. until the pH remains unchanged, and then washed, dried and filtered to prepare tetramercaptan A; under a nitrogen environment, 1 mol of 1-(2-quinoxaline)-1,2,3,4-butanetetrol, 4 mol of mercaptopropionic acid, 0.02 mol of p-toluenesulfonic acid and 6 mol of toluene are mixed, reacted at 75° C. until the pH remains unchanged, and then washed, dried and filtered to prepare tetramercaptan B;

[0032] Step 3: Under a nitrogen environment, 1 mol of tetramercaptan A, 4 mol of tetramercaptan B, 0.02 mol of phenothiazine and 15 mol of N,N-dimethylacetamide were mixed evenly, and then 4 mol of 1,4-butanediol diacrylate was added dropwise and reacted at 9°C for 2.7 hours. After the reaction, the mixture was extracted, washed, dried, filtered, and rotary evaporated to prepare a curing agent;

[0033] Step 4: 20g of epoxy resin E20, 30g of epoxy resin E12, 6g of polyether polyol, 10g of silica powder, 8g of flame retardant, 10g of curing agent, 1g of defoaming agent, 1g of 2-ethyl-4-methylimidazole and 3g of 2-hydroxy-2-methylpropiophenone are mixed to prepare an epoxy resin coating; the epoxy resin coating is applied to the surface of the fin tube, and then dried at 55°C for 27min, and then irradiated under ultraviolet light for 670s, and then washed and dried to prepare a finished product.

[0034] Example 3: Step 1: 16 g of allyl bisphenol A, 10 g of potassium carbonate and 110 g of dimethyl sulfoxide were mixed, and the mixture was continuously heated to 85° C. and stirred for reaction for 5.5 h. 18 g of 4-nitrophthalonitrile was then added and the reaction was continued for 5 h. The reaction product was filtered, washed and dried to prepare a flame retardant.

[0035] Step 2: Under a nitrogen environment, 1 mol of pentaerythritol, 4 mol of mercaptopropionic acid, 0.02 mol of p-toluenesulfonic acid and 6 mol of toluene are mixed, reacted at 70°C until the pH remains unchanged, and then washed, dried and filtered to prepare tetramercaptan A; under a nitrogen environment, 1 mol of 1-(2-quinoxaline)-1,2,3,4-butanetetrol, 4 mol of mercaptopropionic acid, 0.02 mol of p-toluenesulfonic acid and 6 mol of toluene are mixed, reacted at 70°C until the pH remains unchanged, and then washed, dried and filtered to prepare tetramercaptan B;

[0036] Step 3: Under a nitrogen environment, 1 mol of tetramercaptan A, 4 mol of tetramercaptan B, 0.02 mol of phenothiazine and 15 mol of N,N-dimethylacetamide were mixed evenly, and then 4 mol of 1,4-butanediol diacrylate was added dropwise and reacted at 8°C for 2.5 hours. After the reaction, the mixture was extracted, washed, dried, filtered, and rotary evaporated to prepare a curing agent;

[0037] Step 4: 20g of epoxy resin E20, 30g of epoxy resin E12, 6g of polyether polyol, 10g of silica powder, 8g of flame retardant, 10g of curing agent, 1g of defoaming agent, 1g of 2-ethyl-4-methylimidazole and 3g of 2-hydroxy-2-methylpropiophenone are mixed to prepare an epoxy resin coating; the epoxy resin coating is applied to the surface of the fin tube, and then dried at 50°C for 25min, and then irradiated under ultraviolet light for 650s, and then washed and dried to prepare a finished product.

[0038] Example 4: Step 1: 16 g of allyl bisphenol A, 10 g of potassium carbonate and 110 g of dimethyl sulfoxide were mixed, and the mixture was continuously heated to 83° C. and stirred for reaction for 5.2 h. 18 g of 4-nitrophthalonitrile was then added and the reaction was continued for 4.5 h. The reaction product was filtered, washed and dried to prepare a flame retardant.

[0039] Step 2: Under a nitrogen environment, 1 mol of pentaerythritol, 4 mol of mercaptopropionic acid, 0.02 mol of p-toluenesulfonic acid and 6 mol of toluene are mixed, reacted at 65° C. until the pH remains unchanged, and then washed, dried and filtered to prepare tetramercaptan A; under a nitrogen environment, 1 mol of 1-(2-quinoxaline)-1,2,3,4-butanetetrol, 4 mol of mercaptopropionic acid, 0.02 mol of p-toluenesulfonic acid and 6 mol of toluene are mixed, reacted at 65° C. until the pH remains unchanged, and then washed, dried and filtered to prepare tetramercaptan B;

[0040] Step 3: Under a nitrogen environment, 1 mol of tetramercaptan A, 4 mol of tetramercaptan B, 0.02 mol of phenothiazine and 15 mol of N,N-dimethylacetamide were mixed evenly, and then 4 mol of 1,4-butanediol diacrylate was added dropwise and reacted at 7°C for 2.3 hours. After the reaction, the mixture was extracted, washed, dried, filtered, and rotary evaporated to prepare a curing agent;

[0041] Step 4: 20g of epoxy resin E20, 30g of epoxy resin E12, 6g of polyether polyol, 10g of silica powder, 8g of flame retardant, 10g of curing agent, 1g of defoaming agent, 1g of 2-ethyl-4-methylimidazole and 3g of 2-hydroxy-2-methylpropiophenone are mixed to prepare an epoxy resin coating; the epoxy resin coating is applied to the surface of the fin tube, and then dried at 45°C for 23min, and then irradiated under ultraviolet light for 625s, and then washed and dried to prepare a finished product.

[0042] Example 5: Step 1: 16 g of allyl bisphenol A, 10 g of potassium carbonate and 110 g of dimethyl sulfoxide were mixed, and the mixture was continuously heated to 80° C. and stirred for reaction for 5 h. 18 g of 4-nitrophthalonitrile was then added and the reaction was continued for 4 h. The reaction product was filtered, washed and dried to prepare a flame retardant.

[0043] Step 2: Under a nitrogen environment, 1 mol of pentaerythritol, 4 mol of mercaptopropionic acid, 0.02 mol of p-toluenesulfonic acid and 6 mol of toluene are mixed, reacted at 60°C until the pH remains unchanged, and then washed, dried and filtered to prepare tetramercaptan A; under a nitrogen environment, 1 mol of 1-(2-quinoxaline)-1,2,3,4-butanetetrol, 4 mol of mercaptopropionic acid, 0.02 mol of p-toluenesulfonic acid and 6 mol of toluene are mixed, reacted at 60°C until the pH remains unchanged, and then washed, dried and filtered to prepare tetramercaptan B;

[0044] Step 3: Under a nitrogen environment, 1 mol of tetramercaptan A, 4 mol of tetramercaptan B, 0.02 mol of phenothiazine and 15 mol of N,N-dimethylacetamide were mixed evenly, and then 4 mol of 1,4-butanediol diacrylate was added dropwise and reacted at 6°C for 2 hours. After the reaction, the mixture was extracted, washed, dried, filtered, and rotary evaporated to prepare a curing agent;

[0045] Step 4: 20g of epoxy resin E20, 30g of epoxy resin E12, 6g of polyether polyol, 10g of silica powder, 8g of flame retardant, 10g of curing agent, 1g of defoaming agent, 1g of 2-ethyl-4-methylimidazole and 3g of 2-hydroxy-2-methylpropiophenone are mixed to prepare an epoxy resin coating; the epoxy resin coating is applied to the surface of the fin tube, and then dried at 40°C for 20min, and then irradiated under ultraviolet light for 600s, and then washed and dried to prepare a finished product.

[0046] Comparative Example 1: The preparation step of the flame retardant is removed, and the rest is the same as Example 1, and the specific steps are as follows: Step 1: Under a nitrogen environment, 1 mol of pentaerythritol, 4 mol of mercaptopropionic acid, 0.02 mol of p-toluenesulfonic acid and 6 mol of toluene are mixed, reacted at 80° C. until the pH remains unchanged, and then washed, dried, and filtered to prepare tetramercaptan A; Under a nitrogen environment, 1 mol of 1-(2-quinoxaline)-1,2,3,4-butanetetrol, 4 mol of mercaptopropionic acid, 0.02 mol of p-toluenesulfonic acid and 6 mol of toluene are mixed, reacted at 80° C. until the pH remains unchanged, and then washed, dried, and filtered to prepare tetramercaptan B;

[0047] Step 2: Under a nitrogen environment, 1 mol of tetramercaptan A, 4 mol of tetramercaptan B, 0.02 mol of phenothiazine and 15 mol of N,N-dimethylacetamide were mixed evenly, and then 4 mol of 1,4-butanediol diacrylate was added dropwise and reacted at 10°C for 3 hours. After the reaction, the mixture was extracted, washed, dried, filtered, and rotary evaporated to prepare a curing agent;

[0048] Step 3: 20g of epoxy resin E20, 30g of epoxy resin E12, 6g of polyether polyol, 10g of silica powder, 10g of curing agent, 1g of defoaming agent, 1g of 2-ethyl-4-methylimidazole and 3g of 2-hydroxy-2-methylpropiophenone are mixed to prepare an epoxy resin coating; the epoxy resin coating is applied to the surface of the fin tube, and then dried at 60°C for 30min, and then irradiated under ultraviolet light for 700s, and then washed and dried to prepare a finished product.

[0049] Comparative Example 2: The curing agent was replaced with p-phenylenediamine, a commonly used curing agent for epoxy resins. The rest was the same as in Example 1, and the specific steps were as follows: Step 1: 16 g of allyl bisphenol A, 10 g of potassium carbonate, and 110 g of dimethyl sulfoxide were mixed, and the mixture was continuously heated to 90° C. and stirred for reaction for 6 h. 18 g of 4-nitrophthalonitrile was then added and the reaction was continued for 6 h. The reaction product was filtered, washed, and dried to prepare a flame retardant.

[0050] Step 2: 20g of epoxy resin E20, 30g of epoxy resin E12, 6g of polyether polyol, 10g of silica powder, 8g of flame retardant, 10g of p-phenylenediamine curing agent, 1g of defoaming agent, 1g of 2-ethyl-4-methylimidazole and 3g of 2-hydroxy-2-methylpropiophenone are mixed to prepare an epoxy resin coating; the epoxy resin coating is applied to the surface of the fin tube, and then dried at 60°C for 30min, and then irradiated under ultraviolet light for 700s, and then washed and dried to prepare a finished product.

[0051] Detection test:

[0052] Corrosion resistance test: The finished product prepared by the present invention was used as a sample, and the sample was immersed in 3.5wt% NaCl as an electrolyte. The electrochemical performance of the coating was characterized using an electrochemical workstation, and then the corrosion rate was calculated according to the formula.

[0053] Flame retardant performance test: Epoxy resin coating was prepared according to the above method, poured into a polytetrafluoroethylene mold, dried at 60°C for 30 minutes, and then irradiated under ultraviolet light for 700 seconds to prepare a sample with a size of 100 mm × 13 mm × 3 mm. The sample was tested using a vertical combustion apparatus.

[0054] Acid resistance test: The finished product prepared by the present invention was used as a sample. The acid resistance of the sample was tested according to the national standard GB / T9274-1988. The sample was immersed in a 10% sulfuric acid solution for 2 days and then taken out for observation. The results are shown in the following table.

[0055]

[0056]

[0057] Conclusion: The dosage of Examples 1 to 5 remains unchanged, and only some reaction parameters are modified. The experimental data show that there is no significant fluctuation in the performance of the samples. Comparative Example 1: The preparation steps of the flame retardant are removed, and the rest are the same as Example 1. The experimental data show that compared with Example 1, the corrosion rate is 9.1×10 -5 mm / y, the combustion grade changed from V-0 to V-2, and the acid resistance passed. The reason was analyzed as follows: the flame retardant contained a large amount of flame retardant element nitrogen, so after removing it, the flame retardant performance decreased and the combustion grade of the sample became V-2.

[0058] Comparative Example 2: The curing agent was replaced with p-phenylenediamine, a common curing agent for epoxy resin, and the rest was the same as in Example 1. From the experimental data, it can be seen that compared with Example 1, the corrosion rate became 13.2×10 -5mm / y, the combustion grade changed from V-0 to V-1, and blistering occurred during the acid resistance test for 30 hours. The reason for this was that the dosage range of 1,4-butanediol diacrylate was adjusted to a smaller amount, and the dosage was not even enough to allow the thiol and 1,4-butanediol diacrylate to fully undergo a thiol-ene click reaction to generate a hyperbranched curing agent. Therefore, compared with Example 1, the overall mechanical properties of the prepared sample were reduced, the corrosion resistance was reduced, the flame retardancy was reduced, and the acid resistance was also reduced.

[0059] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "include," "comprise," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, method, article, or apparatus comprising a series of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus.

[0060] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art will be able to modify the technical solutions described in the aforementioned embodiments or substitute equivalents for some of the technical features. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A process for preparing a corrosion-resistant composite finned tube, characterized in that: The following steps are involved: Step 1: Allyl bisphenol A, potassium carbonate and dimethyl sulfoxide are mixed, heated to 80-90°C, stirred and reacted for 5-6 hours, and then 4-nitrophthalonitrile is added and the reaction is continued for 4-6 hours. The reaction product is filtered, washed and dried to prepare a flame retardant; Step 2: Under a nitrogen environment, tetramercaptan A, tetramercaptan B, phenothiazine and N,N-dimethylacetamide are uniformly mixed, and 1,4-butanediol diacrylate is added dropwise and reacted at 6-10°C for 2-3 hours. After the reaction is completed, the mixture is extracted, washed, dried, filtered, and rotary evaporated to prepare a curing agent; the molar ratio of tetramercaptan A, tetramercaptan B and 1,4-butanediol diacrylate is 1:(4-5):(4-5); the molar ratio of tetramercaptan A, phenothiazine and N,N-dimethylacetamide is 1:0.02:(15-20); Step 3: Mix epoxy resin E20, epoxy resin E12, polyether polyol, filler, flame retardant, curing agent, defoaming agent, accelerator and photoinitiator to prepare epoxy resin coating; apply the epoxy resin coating to the surface of the fin tube, dry it at 40-60°C for 20-30 minutes, and then irradiate it under ultraviolet light for 600-700 seconds, and then wash and dry it to prepare a finished product.

2. The process for preparing a corrosion-resistant composite finned tube according to claim 1, wherein: In step 1, the contents of the flame retardant components are as follows: by mass: 16-20 parts of allyl bisphenol A, 10-15 parts of potassium carbonate, 110-120 parts of dimethyl sulfoxide, and 18-20 parts of 4-nitrophthalonitrile.

3. The process for preparing a corrosion-resistant composite finned tube according to claim 1, wherein: The preparation method of tetramercaptan A is as follows: pentaerythritol, mercaptopropionic acid, p-toluenesulfonic acid and toluene are mixed under a nitrogen environment, reacted at 60-80° C. until the pH remains unchanged, and then washed, dried and filtered to prepare tetramercaptan A.

4. The process for preparing a corrosion-resistant composite finned tube according to claim 3, wherein: When preparing tetramercaptan A, the molar ratio of pentaerythritol, mercaptopropionic acid, p-toluenesulfonic acid and toluene is 1:(4-4.5):0.02:

6.

5. The process for preparing a corrosion-resistant composite finned tube according to claim 1, wherein: The preparation method of tetrathiol B is as follows: under a nitrogen environment, 1-(2-quinoxaline)-1,2,3,4-butanetetrol, mercaptopropionic acid, p-toluenesulfonic acid and toluene are mixed, reacted at 60-80° C. until the pH remains unchanged, and then washed, dried and filtered to prepare tetrathiol B.

6. The process for preparing a corrosion-resistant composite finned tube according to claim 5, characterized in that: When preparing tetramercaptan B, the molar ratio of 1-(2-quinoxaline)-1,2,3,4-butanetetrol, mercaptopropionic acid, p-toluenesulfonic acid and toluene is 1:(4-5):0.02:

6.

7. The process for preparing a corrosion-resistant composite finned tube according to claim 1, characterized in that: In step three, the contents of each component of the epoxy resin coating are: in parts by mass, 20-30 parts of epoxy resin E20, 20-30 parts of epoxy resin E12, 6-10 parts of polyether polyol, 10-15 parts of filler, 8-15 parts of flame retardant, 10-15 parts of curing agent, 1-2 parts of defoaming agent, 1-2 parts of accelerator, and 3-5 parts of photoinitiator.

8. The process for preparing a corrosion-resistant composite finned tube according to claim 7, characterized in that: The accelerator is 2-ethyl-4-methylimidazole; the photoinitiator is 2-hydroxy-2-methylpropiophenone; and the filler is silicon dioxide powder.

9. The process for preparing a corrosion-resistant composite finned tube according to claim 8, characterized in that: The material of the fin tube is any one of stainless steel and aluminum alloy.

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