A solvent-free high-temperature-resistant silicone-modified epoxy anticorrosive coating and a preparation method thereof

Abstract

The present application relates to the technical field of building coatings, in particular to a solvent-free high-temperature-resistant organic silicon modified epoxy anticorrosive coating and a preparation method thereof. In view of the problems of the existing epoxy coating resin structure being difficult to control, poor heat resistance, loose paint film, and weak comprehensive performance of corrosion resistance and weather resistance, the present application takes tetra(dimethylsiloxy)silane as the core, and synthesizes the four-arm fluorosilicon modified epoxy resin through step-by-step synthesis of carboxyl protection, silicon hydrogen addition, deprotection and fluorine epoxy grafting. The Si-O-Si skeleton has high bond energy, which significantly improves the heat resistance, thermal oxygen resistance and ultraviolet resistance of the coating; the four-arm branched structure reduces the curing internal stress, solves the hard and brittle easy cracking defect of the traditional epoxy, the siloxane skeleton is matched with high crosslinking density to form a dense shielding layer, the fluorine chain gives the hydrophobic, stain-resistant, acid, alkali and salt mist resistant properties, the fluorine, silicon and epoxy three-phase synergistically constructs a multiple corrosion protection mechanism, so that the salt mist resistance, wet heat resistance and weather resistance of the coating are greatly improved, and the coating is suitable for petrochemical and marine high-temperature strong corrosion working conditions.

Description

Technical Field

[0001] This invention relates to the field of architectural coatings technology, specifically to a solvent-free, high-temperature resistant, silicone-modified epoxy anticorrosive coating and its preparation method. Background Technology

[0002] Solvent-free epoxy resin coatings are the most widely used anti-corrosion coating resin materials in the industrial field due to their excellent adhesion, mechanical strength, chemical corrosion resistance, and insulation properties. They are widely used in corrosion protection scenarios such as steel structures, petrochemical equipment, marine engineering, and high-temperature pipelines. However, traditional bisphenol A type epoxy resins have obvious technical shortcomings, including limited curing crosslinking density, high internal stress in the paint film, poor heat aging resistance, brittleness at high temperatures, and insufficient weather resistance and stain resistance. Under harsh conditions such as high temperature, high salt spray, and strong corrosion, they are prone to failure problems such as paint film chalking, cracking, blistering, and peeling, resulting in a significant shortened service life.

[0003] To improve the heat resistance and weather resistance of epoxy resins, current technologies generally employ linear organosilicon monomers to physically blend or simply chemically modify epoxy resins, utilizing the flexibility, high-temperature resistance, and UV resistance of the silicon-oxygen chain segments to compensate for the shortcomings of epoxy. However, conventionally modified resins generally suffer from uneven crosslinking, limited improvement in high-temperature resistance, and insufficient corrosion protection. Therefore, it is necessary to address these shortcomings to further improve the performance of epoxy coatings. Summary of the Invention

[0004] The purpose of this invention is to provide a solvent-free, high-temperature resistant silicone-modified epoxy anticorrosive coating and its preparation method, so as to solve the problem of insufficient heat resistance of solvent-free epoxy coatings.

[0005] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0006] In a first aspect, the present invention provides a method for preparing a solvent-free, high-temperature resistant, organosilicon-modified epoxy anticorrosive coating, comprising the following steps:

[0007] S1. After mixing 4-pentenoic acid with anhydrous dichloromethane, the mixture was cooled to a constant temperature in an ice-water bath. DMAP (4-dimethylaminopyridine) was added, followed by di-tert-butyl dicarbonate. After reacting at low temperature, deionized water was added, the organic phase was separated, and the mixture was washed with deionized water and saturated brine until neutral. After drying by rotary evaporation to constant weight, tert-butyl 4-pentenoic acid was obtained.

[0008] S2. Under nitrogen atmosphere protection, tetra(dimethylsiloxy)silane, Karstedt catalyst and anhydrous toluene were mixed, and 4-pentenoic acid tert-butyl ester was added dropwise. After the addition was completed, the reaction was heated and the solvent was removed by rotary evaporation to obtain the tetra-armed tert-butyl ester protected intermediate.

[0009] S3. The tetra-armed tert-butyl ester protected intermediate was mixed with DCM (anhydrous dichloromethane), cooled to constant temperature in an ice-water bath, and then trifluoroacetic acid was added dropwise. After the addition was completed, the reaction was carried out at low temperature. The organic phase was washed repeatedly with saturated sodium bicarbonate solution until the pH value was neutral. The organic phase was collected and dried by rotary evaporation to constant weight to obtain the tetra-armed carboxyl intermediate.

[0010] S4. Add the four-armed carboxyl intermediate to the co-solvent, add triphenylphosphine, cool in an ice-water bath, and dropwise add it to 1,4-bis(2',3'-epoxypropyl)perfluorobutane. After the dropwise addition is complete, heat the reaction, and evaporate the excess solvent and unreacted monomers under vacuum to obtain the four-armed fluorosilicone modified epoxy resin.

[0011] S5. Mix bisphenol A type epoxy resin, four-arm fluorosilicone modified epoxy resin, and reactive diluent, stir and disperse evenly, then add dispersant, defoamer, titanium dioxide, and barium sulfate, mix evenly, and obtain the main agent;

[0012] 1,3-cyclohexanediamine was used as a curing agent; the main agent and the curing agent were mixed evenly to obtain a solvent-free epoxy anti-corrosion coating.

[0013] Furthermore, in S1, the mass ratio of 4-pentenoic acid, DMAP, and di-tert-butyl dicarbonate is 1:(0.025~0.04):(2.4~2.9).

[0014] During low-temperature reactions, the reaction system temperature is maintained at 0~5℃, and the reaction is stirred for 4~5 hours.

[0015] Furthermore, in S2, the mass ratio of tetrakis(dimethylsiloxy)silane to tert-butyl 4-pentenoate is 1:(2.1~2.15).

[0016] The amount of Karstedt catalyst added is 6~10 ppm;

[0017] During the heating reaction, the temperature is raised to 60~65℃, and the reaction is stirred for 4.5~5.5 hours.

[0018] Furthermore, in S3, the mass ratio of the tetra-arm tert-butyl ester protecting intermediate to trifluoroacetic acid is 1:(5~15).

[0019] During the low-temperature reaction, maintain the reaction system temperature at 0~5℃ and stir the reaction for 1.5~2 hours.

[0020] Furthermore, in S4, the mass ratio of the tetra-armed carboxyl intermediate, 1,4-bis(2',3'-epoxypropyl)perfluorobutane, and triphenylphosphine is 1:(2~2.15):(0.005~0.01).

[0021] When heating the reaction, raise the temperature to 110~115℃ and stir the reaction for 5~6 hours.

[0022] Furthermore, in S4, the co-solvent is a mixed solvent of anhydrous toluene and methyl perfluorobutyl ether, wherein the volume ratio of anhydrous toluene to methyl perfluorobutyl ether is (2~3):1.

[0023] Furthermore, in S5, the mass ratio of bisphenol A type epoxy resin, tetra-arm fluorosilicone modified epoxy resin, reactive diluent, dispersant, defoamer, titanium dioxide, and barium sulfate is (25~40): (10~20): (3~5): (0.2~0.5): (0.4~0.5): (10~15): (15~30).

[0024] Furthermore, in S5, the mass ratio of the main agent to the curing agent is (63.6~111):(7~11.5).

[0025] Furthermore, in S5, the active diluent is 1,4-butanediol diglycidyl ether.

[0026] Secondly, the present invention also provides a solvent-free, high-temperature resistant organosilicon-modified epoxy anticorrosive coating prepared by the above preparation method.

[0027] Compared with the prior art, the beneficial effects achieved by the present invention are:

[0028] This invention addresses the shortcomings of existing technologies, such as poor controllability of resin structure, insufficient high-temperature resistance, poor film density, high VOC content, and weak overall performance in terms of weather resistance, stain resistance, and corrosion prevention. It prepares a solvent-free, high-temperature resistant organosilicon-modified epoxy anticorrosive coating. Firstly, using tetra(dimethylsiloxy)silane as a stable four-armed silicon-oxygen core, a step-by-step controllable process of carboxyl protection, hydrosilylation, low-temperature deprotection, and precise epoxy ring-opening grafting is employed to prepare a four-armed fluorosilicone-modified epoxy resin. The Si-O-Si silicon-oxygen bond energy in the core is much higher than that of carbon-carbon bonds, exhibiting excellent high-temperature resistance, thermal aging resistance, and UV aging resistance, significantly improving the coating's high-temperature service stability. The four-armed star-shaped topology significantly reduces the internal stress during resin curing, avoiding the hard and brittle defects caused by excessively high crosslinking density in traditional epoxy coatings. This allows the coating to possess both high strength and high flexibility, making it less prone to cracking and peeling under high-temperature conditions, and significantly improving its high-temperature corrosion resistance and durability. The silicon-oxygen skeleton enhances film density, effectively blocking moisture and corrosion. The coating utilizes a high cross-linking density in its four-armed star-shaped structure to penetrate corrosive media, creating a multi-layered physical shielding anti-corrosion system. Compared to ordinary silicone-modified epoxy coatings, this system significantly improves anti-corrosion lifespan, weather resistance, and chemical resistance. Furthermore, the introduction of fluorine imparts excellent hydrophobicity, stain resistance, acid and alkali resistance, and salt spray resistance. The fluorine layer provides stain and weather resistance, the silica layer toughens and stabilizes the structure, and the epoxy layer provides adhesion and strength. These three elements form a synergistic multi-layered anti-corrosion mechanism, significantly enhancing the coating's cross-linking density after curing compared to traditional bisphenol A type epoxy coatings. High viscosity, strong molecular chain rigidity, and large residual stress within the paint film make it prone to microcracks under alternating hot and cold temperatures and high temperatures. This invention addresses these defects with a four-arm fluorosilicone modified epoxy resin possessing multi-branched flexible silicone side chains. Introduced into the paint film system, these chains buffer the internal stress generated by crosslinking shrinkage, preventing brittleness and hardness. Simultaneously, the multi-epoxy side chains can undergo multi-point crosslinking with the 1,3-cyclohexanediamine curing agent, resulting in a higher overall crosslinking density and a stable pencil hardness of ≥1H for the paint film. This provides both scratch-resistant mechanical strength and high-temperature crack-resistant flexibility. Furthermore, traditional epoxy resins with carbon-carbon backbones are prone to photodegradation due to UV absorption, leading to rapid chalking, loss of gloss, and cracking with long-term outdoor use. Ordinary linear silicone-modified epoxy resins lack sufficient UV shielding capabilities, while fluoropolymer-modified epoxy resins exhibit poor compatibility with epoxy groups, resulting in easy precipitation and limited improvement in weather resistance. The silicon-oxygen segments grafted onto the four-arm macromolecules of this invention can absorb and dissipate ultraviolet light energy, blocking the photo-oxidative chain scission of epoxy groups; the perfluoroalkyl group has extremely strong resistance to ultraviolet light, ozone, and rain erosion. The two work together to inhibit chalking, loss of gloss, and discoloration of the paint film, so that the coating prepared by this invention has significantly improved salt spray resistance, ultraviolet aging resistance, and damp heat aging resistance, making it suitable for strong corrosive extreme working conditions such as marine, petrochemical, and high-temperature chemical industries. Attached Figure Description

[0029] Figure 1 This is a photograph of the solvent-free, high-temperature resistant organosilicon-modified epoxy anticorrosive coating prepared in Example 3 of this invention after undergoing a 240-hour neutral salt spray test.

[0030] Figure 2 This is a chemical reaction equation diagram for step S1 in embodiment 3 of the present invention;

[0031] Figure 3 This is a chemical reaction equation diagram for step S2 in Example 3 of the present invention;

[0032] Figure 4 This is a chemical reaction equation diagram for step S3 in Example 3 of the present invention;

[0033] Figure 5 This is a chemical reaction equation diagram for step S4 in embodiment 3 of the present invention. Detailed Implementation

[0034] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0035] Example 1

[0036] A method for preparing a solvent-free, high-temperature resistant, silicone-modified epoxy anticorrosive coating includes the following steps:

[0037] S1. After mixing 4-pentenoic acid with anhydrous dichloromethane, the mixture was cooled to a constant temperature in an ice-water bath. DMAP was added, and then di-tert-butyl dicarbonate was added in three equal batches with a 5-minute interval between each batch. After the addition was completed, the reaction system temperature was maintained at 0°C, and the mixture was stirred for 5 hours. Deionized water was added, the organic phase was separated, and the mixture was washed with deionized water and saturated brine until neutral. After drying by rotary evaporation to a constant weight, tert-butyl 4-pentenoic acid was obtained.

[0038] The mass ratio of 4-pentenoic acid, DMAP, and di-tert-butyl dicarbonate is 1:0.025:2.4.

[0039] S2. Under nitrogen atmosphere protection, tetra(dimethylsiloxy)silane, Karstedt catalyst and anhydrous toluene were mixed, and 4-pentenoic acid tert-butyl ester was added dropwise. After the addition was completed, the mixture was heated to 60°C and stirred for 5.5 h. After the solvent was removed by rotary evaporation, the tetra-armed tert-butyl ester protected intermediate was obtained.

[0040] The mass ratio of tetra(dimethylsiloxy)silane to tert-butyl 4-pentenoate is 1:2.1; the amount of Karstedt catalyst added is 6 ppm.

[0041] S3. The tetra-armed tert-butyl ester protected intermediate was mixed with DCM, cooled to constant temperature in an ice-water bath, and then trifluoroacetic acid was added dropwise. After the addition was completed, the reaction system temperature was maintained at 0℃, and the reaction was stirred for 2 hours. The organic phase was washed several times with saturated sodium bicarbonate solution until the pH value was neutral. The organic phase was collected and dried by rotary evaporation to constant weight to obtain the tetra-armed carboxyl intermediate.

[0042] The mass ratio of the tetra-arm tert-butyl ester protecting intermediate to trifluoroacetic acid is 1:5.

[0043] S4. Add the four-armed carboxyl intermediate to the co-solvent, add triphenylphosphine, mix well, cool to a constant temperature in an ice-water bath, and then dropwise add it to 1,4-bis(2',3'-epoxypropyl)perfluorobutane. During the dropwise addition, control the temperature of the reaction system to be maintained within 0~5℃. After the dropwise addition is completed, raise the temperature to 110℃, stir the reaction for 6h, and then evaporate the excess solvent and unreacted monomers under vacuum to obtain the four-armed fluorosilicone modified epoxy resin.

[0044] The mass ratio of the tetra-armed carboxyl intermediate, 1,4-bis(2',3'-epoxypropyl)perfluorobutane, and triphenylphosphine is 1:2:0.005.

[0045] The co-solvent is a mixture of anhydrous toluene and methyl perfluorobutyl ether, wherein the volume ratio of anhydrous toluene to methyl perfluorobutyl ether is 2:1.

[0046] S5. Mix bisphenol A type epoxy resin, four-arm fluorosilicone modified epoxy resin, and reactive diluent, stir and disperse evenly, then add dispersant, defoamer, titanium dioxide, and barium sulfate, mix evenly, and obtain the main agent;

[0047] The mass ratio of bisphenol A type epoxy resin, four-arm fluorosilicone modified epoxy resin, reactive diluent, dispersant, defoamer, titanium dioxide, and barium sulfate is 25:10:3:0.2:0.4:10:15.

[0048] 1,3-cyclohexanediamine was used as a curing agent; the main agent and the curing agent were mixed evenly at a mass ratio of 63.6:7 to obtain a solvent-free epoxy anti-corrosion coating.

[0049] Example 2

[0050] A method for preparing a solvent-free, high-temperature resistant, silicone-modified epoxy anticorrosive coating includes the following steps:

[0051] S1. After mixing 4-pentenoic acid with anhydrous dichloromethane, the mixture was cooled to a constant temperature in an ice-water bath. DMAP was added, and then di-tert-butyl dicarbonate was added in three equal batches with a 5-minute interval between each batch. After the addition was completed, the reaction system temperature was maintained at 2°C, and the mixture was stirred for 4.5 hours. Deionized water was added, the organic phase was separated, and the mixture was washed with deionized water and saturated brine until neutral. The mixture was then dried by rotary evaporation to a constant weight to obtain tert-butyl 4-pentenoic acid.

[0052] The mass ratio of 4-pentenoic acid, DMAP, and di-tert-butyl dicarbonate is 1:0.03:2.7.

[0053] S2. Under nitrogen atmosphere protection, tetra(dimethylsiloxy)silane, Karstedt catalyst and anhydrous toluene were mixed, and 4-pentenoic acid tert-butyl ester was added dropwise. After the addition was completed, the temperature was raised to 63°C, and the reaction was stirred for 5 hours. After the solvent was removed by rotary evaporation, the tetra-armed tert-butyl ester protected intermediate was obtained.

[0054] The mass ratio of tetra(dimethylsiloxy)silane to tert-butyl 4-pentenoate is 1:2.15; the amount of Karstedt catalyst added is 8 ppm.

[0055] S3. The tetra-armed tert-butyl ester protected intermediate was mixed with DCM, cooled to a constant temperature in an ice-water bath, and then trifluoroacetic acid was added dropwise. After the addition was completed, the reaction system temperature was maintained at 3°C, and the reaction was stirred for 1.5 h. The organic phase was washed several times with saturated sodium bicarbonate solution until the pH value was neutral. The organic phase was collected and dried by rotary evaporation to constant weight to obtain the tetra-armed carboxyl intermediate.

[0056] The mass ratio of the tetra-arm tert-butyl ester protecting intermediate to trifluoroacetic acid is 1:10.

[0057] S4. Add the four-armed carboxyl intermediate to the co-solvent, add triphenylphosphine, mix well, cool to a constant temperature in an ice-water bath, and then add it dropwise to 1,4-bis(2',3'-epoxypropyl)perfluorobutane. During the dropwise addition, control the temperature of the reaction system to be maintained within 0~5℃. After the dropwise addition is completed, raise the temperature to 112℃, stir the reaction for 5.5h, and evaporate the excess solvent and unreacted monomers under vacuum to obtain the four-armed fluorosilicone modified epoxy resin.

[0058] The mass ratio of the tetra-armed carboxyl intermediate, 1,4-bis(2',3'-epoxypropyl)perfluorobutane, and triphenylphosphine is 1:2.1:0.008.

[0059] The co-solvent is a mixture of anhydrous toluene and methyl perfluorobutyl ether, wherein the volume ratio of anhydrous toluene to methyl perfluorobutyl ether is 2.5:1.

[0060] S5. Mix bisphenol A type epoxy resin, four-arm fluorosilicone modified epoxy resin, and reactive diluent, stir and disperse evenly, then add dispersant, defoamer, titanium dioxide, and barium sulfate, mix evenly, and obtain the main agent;

[0061] The mass ratio of bisphenol A type epoxy resin, four-arm fluorosilicone modified epoxy resin, reactive diluent, dispersant, defoamer, titanium dioxide, and barium sulfate is 32:15:4:0.3:0.45:12:25.

[0062] 1,3-cyclohexanediamine was used as a curing agent; the main agent and the curing agent were mixed evenly at a mass ratio of 88.75:9.5 to obtain a solvent-free epoxy anti-corrosion coating.

[0063] Example 3

[0064] A method for preparing a solvent-free, high-temperature resistant, silicone-modified epoxy anticorrosive coating includes the following steps:

[0065] S1. 4-Pentenoic acid was mixed with anhydrous dichloromethane and cooled to a constant temperature in an ice-water bath. DMAP was added, followed by the addition of di-tert-butyl dicarbonate in three equal batches, with a 5-minute interval between each batch. After the addition was complete, the reaction system temperature was maintained at 5°C, and the mixture was stirred for 4 hours. Deionized water was added, and the organic phase was separated. The organic phase was washed with deionized water and saturated brine until neutral, and then dried by rotary evaporation to constant weight to obtain tert-butyl 4-pentenoic acid (its chemical reaction equation is as follows). Figure 2 (as shown)

[0066] The mass ratio of 4-pentenoic acid, DMAP, and di-tert-butyl dicarbonate is 1:0.04:2.9.

[0067] S2. Under a nitrogen atmosphere, tetra(dimethylsiloxy)silane, Karstedt catalyst, and anhydrous toluene were mixed, and tert-butyl 4-pentenoate was added dropwise. After the addition was complete, the mixture was heated to 65°C and stirred for 4.5 hours. The solvent was then removed by rotary evaporation to obtain the tetra-armed tert-butyl ester protected intermediate (its chemical reaction equation is as follows). Figure 3 (as shown)

[0068] The mass ratio of tetra(dimethylsiloxy)silane to tert-butyl 4-pentenoate is 1:2.15; the amount of Karstedt catalyst added is 10 ppm.

[0069] S3. The tetra-armed tert-butyl ester protected intermediate was mixed with DCM, cooled to a constant temperature in an ice-water bath, and then trifluoroacetic acid was added dropwise. After the addition was complete, the reaction system temperature was maintained at 5°C, and the mixture was stirred for 1.5 h. The organic phase was washed several times with saturated sodium bicarbonate solution until the pH was neutral. The organic phase was then collected and dried by rotary evaporation to constant weight to obtain the tetra-armed carboxyl intermediate (its chemical reaction equation is as follows). Figure 4 (as shown)

[0070] The mass ratio of the tetra-arm tert-butyl ester protecting intermediate to trifluoroacetic acid is 1:15.

[0071] S4. The four-armed carboxyl intermediate was added to the co-solvent, followed by triphenylphosphine. After thorough mixing, the mixture was cooled to a constant temperature in an ice-water bath and then added dropwise to 1,4-bis(2',3'-epoxypropyl)perfluorobutane. During the addition, the temperature of the reaction system was maintained between 0 and 5°C. After the addition was completed, the temperature was raised to 115°C, and the reaction was stirred for 5 hours. Excess solvent and unreacted monomers were evaporated under vacuum to obtain the four-armed fluorosilicone modified epoxy resin (its chemical reaction equation is as follows). Figure 5 (as shown)

[0072] The mass ratio of the tetra-armed carboxyl intermediate, 1,4-bis(2',3'-epoxypropyl)perfluorobutane, and triphenylphosphine is 1:2.15:0.01.

[0073] The co-solvent is a mixture of anhydrous toluene and methyl perfluorobutyl ether, wherein the volume ratio of anhydrous toluene to methyl perfluorobutyl ether is 3:1.

[0074] S5. Mix bisphenol A type epoxy resin, four-arm fluorosilicone modified epoxy resin, and reactive diluent, stir and disperse evenly, then add dispersant, defoamer, titanium dioxide, and barium sulfate, mix evenly, and obtain the main agent;

[0075] The mass ratio of bisphenol A type epoxy resin, four-arm fluorosilicone modified epoxy resin, reactive diluent, dispersant, defoamer, titanium dioxide, and barium sulfate is 40:20:5:0.5:0.5:15:30.

[0076] 1,3-cyclohexanediamine was used as a curing agent; the main agent and the curing agent were mixed evenly at a mass ratio of 111:11.5 to obtain a solvent-free epoxy anti-corrosion coating.

[0077] Comparative Example 1

[0078] Compared with Example 3, this comparative example did not prepare a four-arm fluorosilicone modified epoxy resin, but only used an equal mass of bisphenol A type epoxy resin as a replacement, and the remaining steps were the same as in Example 3.

[0079] Comparative Example 2

[0080] Compared with Example 3, this comparative example did not perform steps S1 and S3, but only used an equimolar amount of 4-pentenoic acid to participate in the S2 reaction;

[0081] A method for preparing a solvent-free, high-temperature resistant, silicone-modified epoxy anticorrosive coating includes the following steps:

[0082] S2. Under nitrogen atmosphere protection, tetra(dimethylsiloxy)silane, Karstedt catalyst and anhydrous toluene were mixed, and 4-pentenoic acid was added dropwise. After the addition was completed, the mixture was heated to 65°C and stirred for 4.5 h. After the solvent was removed by rotary evaporation, a four-armed carboxyl intermediate was obtained.

[0083] The mass ratio of tetra(dimethylsiloxy)silane to 4-pentenoic acid is 1:1.37; the amount of Karstedt catalyst added is 10 ppm.

[0084] S4. Add the four-armed carboxyl intermediate to the co-solvent, add triphenylphosphine, mix well, cool to a constant temperature in an ice-water bath, and then dropwise add it to 1,4-bis(2',3'-epoxypropyl)perfluorobutane. During the dropwise addition, control the temperature of the reaction system to be maintained within 0~5℃. After the dropwise addition is completed, raise the temperature to 115℃, stir the reaction for 5h, and then evaporate the excess solvent and unreacted monomers under vacuum to obtain the four-armed fluorosilicone modified epoxy resin.

[0085] The mass ratio of the tetra-armed carboxyl intermediate, 1,4-bis(2',3'-epoxypropyl)perfluorobutane, and triphenylphosphine is 1:2.15:0.01.

[0086] The co-solvent is a mixture of anhydrous toluene and methyl perfluorobutyl ether, wherein the volume ratio of anhydrous toluene to methyl perfluorobutyl ether is 3:1.

[0087] S5. Mix bisphenol A type epoxy resin, four-arm fluorosilicone modified epoxy resin, and reactive diluent, stir and disperse evenly, then add dispersant, defoamer, titanium dioxide, and barium sulfate, mix evenly, and obtain the main agent;

[0088] The mass ratio of bisphenol A type epoxy resin, four-arm fluorosilicone modified epoxy resin, reactive diluent, dispersant, defoamer, titanium dioxide, and barium sulfate is 40:20:5:0.5:0.5:15:30.

[0089] 1,3-cyclohexanediamine was used as a curing agent; the main agent and the curing agent were mixed evenly at a mass ratio of 111:11.5 to obtain a solvent-free epoxy anti-corrosion coating.

[0090] Detection method:

[0091] The solvent-free epoxy anti-corrosion coatings prepared in Examples 1-3 and Comparative Examples 1-2 were sprayed onto the surface of carbon steel plates and cured into a film to obtain test samples.

[0092] According to the GB / T 1771-2007 testing standard, the test samples prepared in Examples 1-3 and Comparative Examples 1-2 were subjected to neutral salt spray resistance testing.

[0093] According to the GB / T 9274-1988 testing standard, the water resistance of the test samples prepared in Examples 1-3 and Comparative Examples 1-2 was tested.

[0094] According to the GB / T 14522-2008 testing standard, the aging resistance performance of the test samples prepared in Examples 1-3 and Comparative Examples 1-2 was tested.

[0095] According to the GB / T 1735-2009 testing standard, the heat resistance of the test samples prepared in Examples 1-3 and Comparative Examples 1-2 was tested. The test conditions were: heat preservation at 280℃ for 3 hours, and then color difference was tested.

[0096] According to the GB / T 6739-2006 testing standard, the hardness of the test samples prepared in Examples 1-3 and Comparative Examples 1-2 was tested.

[0097] The test results are shown in Table 1 below.

[0098] Table 1. Performance test results of solvent-free epoxy anticorrosion coatings prepared in Examples 1-3 and Comparative Examples 1-2 after sample preparation.

[0099]

[0100] As shown in the table above, in Examples 1-3 of this invention, as the proportion of the four-arm fluorosilicone modified epoxy resin increased (10→15→20 parts) and the process parameters moved closer to the high end of the preferred range, the coating performance improved simultaneously—the heat resistance color difference decreased from ≤0.7 to ≤0.5, the neutral salt spray resistance increased from ≥2200h to ≥2700h, and the water resistance increased from ≥900h to ≥1200h. This indicates that the core component and the step-by-step process have a positive synergistic effect on heat resistance and corrosion resistance.

[0101] Comparative Example 1 data shows that without the addition of four-arm fluorosilicone modified epoxy resin, the neutral salt spray resistance drops sharply to ≤1000h before blistering, water resistance to ≤300h before blistering and peeling, aging powdering resistance reaches level 3, and heat resistance color difference ≥0.8. Compared to Example 3, the overall performance deteriorates significantly, directly proving that this component is key to improving coating density, corrosion resistance life, and weather resistance. Comparative Example 2, by omitting the S1 / S3 stepwise protection-deprotection steps, leads to further deterioration in coating performance in terms of neutral salt spray resistance. Even if the final formulation contains fluorosilicone components, without the stepwise controllable process of "protection-addition-deprotection-grafting," an effective four-arm star topology cannot be formed, further demonstrating the necessity of the stepwise process.

[0102] 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 foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing a solvent-free high-temperature-resistant silicone-modified epoxy anticorrosive coating, characterized in that, Includes the following steps: S1. After mixing 4-pentenoic acid with anhydrous dichloromethane, the mixture was cooled to a constant temperature in an ice-water bath. DMAP was added, followed by di-tert-butyl dicarbonate. After reacting at low temperature, deionized water was added, the organic phase was separated, and the mixture was washed with deionized water and saturated brine until neutral. The mixture was then dried by rotary evaporation to a constant weight to obtain tert-butyl 4-pentenoic acid. S2. Under nitrogen atmosphere protection, tetra(dimethylsiloxy)silane, Karstedt catalyst and anhydrous toluene were mixed, and 4-pentenoic acid tert-butyl ester was added dropwise. After the addition was completed, the reaction was heated and the solvent was removed by rotary evaporation to obtain the tetra-armed tert-butyl ester protected intermediate. S3. The tetra-armed tert-butyl ester protected intermediate was mixed with DCM, cooled to constant temperature in an ice-water bath, and then trifluoroacetic acid was added dropwise. After the addition was completed, the reaction was carried out at low temperature. The organic phase was washed several times with saturated sodium bicarbonate solution until the pH value of the organic phase was neutral. The organic phase was collected and dried by rotary evaporation to constant weight to obtain the tetra-armed carboxyl intermediate. S4. Add the four-armed carboxyl intermediate to the co-solvent, add triphenylphosphine, cool in an ice-water bath, and dropwise add it to 1,4-bis(2',3'-epoxypropyl)perfluorobutane. After the dropwise addition is complete, heat the reaction, and evaporate the excess solvent and unreacted monomers under vacuum to obtain the four-armed fluorosilicone modified epoxy resin. S5. Mix bisphenol A type epoxy resin, four-arm fluorosilicone modified epoxy resin, and reactive diluent, stir and disperse evenly, then add dispersant, defoamer, titanium dioxide, and barium sulfate, mix evenly, and obtain the main agent; 1,3-cyclohexanediamine was used as a curing agent; the main agent and the curing agent were mixed evenly to obtain a solvent-free epoxy anti-corrosion coating.

2. The preparation method of the solvent-free high-temperature-resistant silicone-modified epoxy anticorrosive coating according to claim 1, characterized in that: In S1, the mass ratio of 4-pentenoic acid, DMAP, and di-tert-butyl dicarbonate is 1:(0.025~0.04):(2.4~2.9). During low-temperature reactions, the reaction system temperature is maintained at 0~5℃, and the reaction is stirred for 4~5 hours.

3. The preparation method of the solvent-free high-temperature-resistant silicone-modified epoxy anticorrosive coating of claim 1, characterized in that: In S2, the mass ratio of tetra(dimethylsiloxy)silane to tert-butyl 4-pentenoate is 1:(2.1~2.15). The amount of Karstedt catalyst added is 6~10 ppm; During the heating reaction, the temperature is raised to 60~65℃, and the reaction is stirred for 4.5~5.5 hours.

4. The preparation method of a solvent-free, high-temperature resistant, organosilicon-modified epoxy anticorrosive coating according to claim 1, characterized in that: In S3, the mass ratio of the tetra-arm tert-butyl ester protecting intermediate to trifluoroacetic acid is 1:(5~15). During the low-temperature reaction, maintain the reaction system temperature at 0~5℃ and stir the reaction for 1.5~2 hours.

5. The method for preparing a solvent-free, high-temperature resistant organosilicon-modified epoxy anticorrosive coating according to claim 1, characterized in that: In S4, the mass ratio of the four-armed carboxyl intermediate, 1,4-bis(2',3'-epoxypropyl)perfluorobutane, and triphenylphosphine is 1:(2~2.15):(0.005~0.01). When heating the reaction, raise the temperature to 110~115℃ and stir the reaction for 5~6 hours.

6. The method for preparing a solvent-free, high-temperature resistant organosilicon-modified epoxy anticorrosive coating according to claim 1, characterized in that: In S4, the co-solvent is a mixed solvent of anhydrous toluene and methyl perfluorobutyl ether, wherein the volume ratio of anhydrous toluene to methyl perfluorobutyl ether is (2~3):

1.

7. The method for preparing a solvent-free, high-temperature resistant organosilicon-modified epoxy anticorrosive coating according to claim 1, characterized in that: In S5, the mass ratio of bisphenol A type epoxy resin, four-arm fluorosilicone modified epoxy resin, reactive diluent, dispersant, defoamer, titanium dioxide, and barium sulfate is (25~40): (10~20): (3~5): (0.2~0.5): (0.4~0.5): (10~15): (15~30).

8. The method for preparing a solvent-free, high-temperature resistant, organosilicon-modified epoxy anticorrosive coating according to claim 1, characterized in that: In S5, the mass ratio of the main agent to the curing agent is (63.6~111):(7~11.5).

9. The method for preparing a solvent-free, high-temperature resistant organosilicon-modified epoxy anticorrosive coating according to claim 1, characterized in that: In S5, the active diluent is 1,4-butanediol diglycidyl ether.

10. A solvent-free, high-temperature resistant, silicone-modified epoxy anticorrosive coating, characterized in that, It is prepared using the preparation method described in any one of claims 1 to 9.

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