Epoxy resin-based fireproof thermal insulation coating material, preparation method and application thereof

Abstract

The application discloses an epoxy resin-based fireproof thermal insulation coating as well as a preparation method and application thereof, and relates to the technical field of fireproof coating. The epoxy resin-based fireproof thermal insulation coating prepared by the application comprises an epoxy resin base material and modified ammonium polyphosphate; the epoxy resin base material is prepared by the reaction of an epoxy resin and a hyperbranched block copolymer; the hyperbranched block copolymer is prepared by using a hyperbranched polyvinyl hydroxyl as an initiator, and simultaneously introducing a double-end hydroxyl poly-p-dioxanone and a thiophosphoric acid triphenyl isocyanate into the hyperbranched block copolymer under the action of an organic base to chain-extend the hyperbranched block copolymer and the epoxy resin to form a stable crosslinking structure, so that the flame-retardant property is improved, the thermal stability is ensured, the modified ammonium polyphosphate is prepared by coating a polyaldehyde-based polyester and a polyamino polyether on the surface of the ammonium polyphosphate, and the flame-retardant property and the adhesion of the coating are further improved.

Description

Technical Field

[0001] This invention relates to the field of fire-retardant coating technology, specifically to an epoxy resin-based fire-retardant and heat-insulating coating, its preparation method, and its application. Background Technology

[0002] Epoxy resin coatings are a type of high-performance coating that uses epoxy resin as the main film-forming substance. Their core characteristics stem from the epoxy groups and polar bonds in the epoxy resin molecule, which, through cross-linking with a curing agent, form a three-dimensional network structure, endowing the coating with excellent adhesion, mechanical strength, and chemical stability. Epoxy resin coatings occupy an irreplaceable position in fields such as corrosion protection, insulation, and fireproofing, becoming the mainstream choice for industrial protection and functional coatings.

[0003] Epoxy resin coatings also have limitations. When used in the petrochemical and construction fields, they are prone to cracking under frequent impacts, which affects their performance. Furthermore, they have high requirements for flame retardancy and adhesion. Therefore, this invention studies and prepares an epoxy resin-based fireproof and heat-insulating coating that combines high strength, flame retardancy, and high adhesion to solve this problem. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide an epoxy resin-based fireproof and heat-insulating coating, its preparation method and application.

[0005] The present invention provides a technical solution to solve the above-mentioned technical problems: an epoxy resin-based fireproof and heat-insulating coating, comprising the following raw materials by weight: 20-30 parts epoxy resin base material, 50-70 parts flame retardant, 100-200 parts expanded perlite, 2-4 parts glass fiber, 10-30 parts film-forming agent, 2-5 parts curing agent, and 1-3 parts defoamer; wherein the epoxy resin base material is prepared by reacting epoxy resin with a hyperbranched block copolymer; and the flame retardant comprises modified ammonium polyphosphate and melamine in a mass ratio of 5:1-2.

[0006] Preferably, the hyperbranched block copolymer is prepared by reacting hydroxyl hyperbranched polyethylene, dihydroxyl-terminated poly(p-dioxanone), and triphenyl isocyanate thiophosphate.

[0007] Preferably, the modified ammonium polyphosphate is prepared by coating the surface of ammonium polyphosphate with a polyaldehyde polyester and a polyamino polyether; the polyaldehyde polyester is prepared by reacting a hydroxyl-terminated hyperbranched polyester with an aldehyde-modified polyacrylic acid; the aldehyde-modified polyacrylic acid is prepared by polymerizing acrylic acid with acrolein; and the polyamino polyether is prepared by reacting epichlorohydrin, dodecyl alcohol polyether and ammonia.

[0008] Preferably, the film-forming agent is dodecyl alcohol ester; the curing agent is polyamide; and the defoamer is nonylphenol polyoxyethylene ether.

[0009] Preferably, the preparation method of the epoxy resin-based fire-retardant and heat-insulating coating includes the following specific steps:

[0010] S1. Under a nitrogen atmosphere, hydroxyl hyperbranched polyethylene, dihydroxyl-terminated poly(p-dioxane)-co-dioxane, and tetrahydrofuran were mixed at a mass ratio of 0.6:(0.4~0.6):3. After stirring evenly, a tetrahydrofuran solution of dibutyltin dilaurate with a mass fraction of 3~5% was added dropwise at a rate of 1~3 ml / min, which was 0.08~0.1 times the mass of the hydroxyl hyperbranched polyethylene. The reaction was continued with stirring for 15~20 min. Then, triphenyl isocyanate thiophosphate with a mass fraction of 0.4~0.6 times the mass of the hydroxyl hyperbranched polyethylene was added. The temperature was raised to 60~80℃ and the reaction was carried out for 6~7 h. The reaction was quenched with glacial acetic acid, precipitated with methanol, filtered, and washed with methanol 3~5 times. The mixture was then dried under vacuum at 60~70℃ to obtain the hyperbranched block copolymer.

[0011] S2. Mix epoxy resin and hyperbranched block copolymer at a mass ratio of 10:1~3, heat to 60~80℃, stir and mix at 400~600rpm for 30~40min, cool to 48~52℃, add curing agent methylhexahydrophthalic anhydride at 6~7 times the mass of epoxy resin, continue stirring and reacting for 8~15min, then add accelerator 2,4,6-tris(dimethylaminomethyl)phenol at 0.01~0.03 times the mass of epoxy resin, continue stirring and reacting for 8~10min, degas under vacuum, heat to 80~82℃, react for 2~3h, heat to 120~122℃, continue reacting for 2h, heat to 50~52℃, continue reacting for 1~2h, to obtain epoxy resin base material;

[0012] S3. Mix aldehyde-modified polyacrylic acid, ethylene glycol, p-toluenesulfonic acid, and dimethyl sulfoxide in a mass ratio of 2:(1~2):(0.02~0.03):(4~5), heat to 58~62℃, react for 2~3 hours, add 1.1~1.2 times the mass of aldehyde-modified polyacrylic acid terminal hydroxyl hyperbranched polyester, and 0.001~0.002 times the mass of aldehyde-modified polyacrylic acid catalyst 4-dimethylaminopyridine, cool to 48~52℃, and add 1~3 ml / A solution of N,N'-dicyclohexylcarbodiimide in dimethyl sulfoxide with a mass fraction of 30-50% was added dropwise at a rate of 0.22-0.24 times the mass of aldehyde-modified polyacrylic acid at a rate of min. The temperature was raised to 78-82℃ and the reaction was carried out for 8-9 hours. Then, hydrochloric acid with a mass fraction of 0.03-0.04% was added with a mass fraction of 1-1.2 times the mass of aldehyde-modified polyacrylic acid at a rate of 0.03-0.04%. The temperature was lowered to 38-42℃ and the reaction was carried out for 3-4 hours. The mixture was dialyzed and freeze-dried at -40 to -60℃ to obtain polyaldehyde-modified polyester.

[0013] S4. Mix ammonium polyphosphate, ethanol, and deionized water at a mass ratio of 1:(2~3):1, sonicate at 40~60kHz for 20~30min, add 0.2~0.3 times the mass of ammonium polyphosphate and polyaldehyde polyester, heat to 60~62℃, react for 6~8h, then add 0.1~0.2 times the mass of ammonium polyphosphate and 0.005~0.007 times the mass of ammonium polyphosphate and p-toluenesulfonic acid catalyst, heat to 80~82℃, react for 8~10h, cool, centrifuge, wash with ethanol 3~5 times, and vacuum dry at 60~70℃ to obtain modified ammonium polyphosphate;

[0014] S5. By weight, mix modified ammonium polyphosphate and melamine to prepare a fire-retardant coating; mix epoxy resin base material and film-forming agent and add to a reactor, stir at 600~800 rpm for 8~10 min, heat to 50~60℃, add fire-retardant coating, disperse at 1000~2000 rpm for 20~30 min, add expanded perlite and glass fiber, stir at 300~500 rpm for 10~13 min, add defoamer and curing agent, continue stirring for 5~8 min, degas under vacuum to obtain epoxy resin-based fireproof and heat-insulating coating.

[0015] Preferably, in step S1, the preparation method of hydroxyl hyperbranched polyethylene is as follows: Under a nitrogen atmosphere, ethylene, hydroxyethyl acrylate, catalyst di-(2,6-dimethylphenyl)hexamethylenediimide nickel bromide and toluene are mixed in a mass ratio of 1:(0.08~0.14):(0.002~0.004):(3~5), heated to 30~40℃, pressure 0.5~1.5MPa, and reacted for 2~6h. Then, 20~30 times the mass of ethylene is added to an ethanol solution of sodium hydroxide with a mass fraction of 20~25%, and the reaction is continued for 30~50min. The mixture is filtered and washed 3~5 times with methanol and deionized water in sequence, and then dried under vacuum at 60~80℃ to obtain hydroxyl hyperbranched polyethylene.

[0016] Preferably, in step S1, the preparation method of the hydroxyl-terminated poly(p-dioxane) is as follows: under a nitrogen atmosphere, p-dioxane and butanediol are mixed at a mass ratio of 20-40:1-3, heated to 80-110°C, stirred evenly, and then a catalyst solution of stannous octoate with a mass fraction of 2-4% (0.3-0.6 times the mass of p-dioxane) is added. The mixture is reacted for 48-72 hours, cooled to room temperature, and pulverized to obtain the hydroxyl-terminated poly(p-dioxane).

[0017] Preferably, in step S1, the preparation method of aldehyde-based polyacrylic acid is as follows: Under a nitrogen atmosphere, acrylic acid and deionized water are mixed at a mass ratio of 1:1~2, stirred and dissolved, and the pH is adjusted to 6.5~7.5 with 30% sodium hydroxide. Acrolein and ammonium persulfate at 0.4~0.8 times the mass of acrylic acid and 0.01~0.03 times the mass of acrylic acid are added. The temperature is raised to 50~60℃ and reacted for 8~12 hours. The pH is adjusted to 2.0~2.2 with hydrochloric acid, and then precipitated with acetone. After dissolving in deionized water, it is precipitated with acetone again. Finally, it is vacuum dried at 40~50℃ to obtain aldehyde-based polyacrylic acid.

[0018] Preferably, in step S3, the preparation method of the polyamino polyether is as follows: under a nitrogen atmosphere, dodecyl alcohol polyether and DMC catalyst are mixed at a mass ratio of 10:0.1~0.2, heated to 115~120℃, and epichlorohydrin with a mass of 1~2 times the mass of dodecyl alcohol polyether is added dropwise at a rate of 1~3 ml / min. The temperature is raised to 125~135℃, and the reaction is carried out for 5~6 h. After vacuum distillation, ammonia water with a mass fraction of 25~28% and toluene with a mass fraction of 0.4~0.6 times the mass of dodecyl alcohol polyether are added. The temperature is raised to 50~52℃, and the reaction is carried out for 3~4 h. The mixture is separated and washed 3~5 times with deionized water, and the polyamino polyether is obtained by rotary evaporation.

[0019] Preferably, the epoxy resin-based fireproof and heat-insulating coating is used in the petrochemical and construction fields.

[0020] Compared with the prior art, the beneficial effects achieved by the present invention are:

[0021] The epoxy resin-based fireproof and heat-insulating coating prepared by the present invention includes an epoxy resin base and modified ammonium polyphosphate; the epoxy resin base is obtained by reacting epoxy resin with hyperbranched block copolymer;

[0022] Hyperbranched block copolymers are prepared by reacting hydroxyl-modified hyperbranched polyethylene, dihydroxyl-terminated poly(p-dioxanone), and triphenyl isocyanate thiophosphate. Using hydroxyl-modified hyperbranched polyethylene as an initiator, the copolymer reacts with dihydroxyl-terminated poly(p-dioxanone) under the action of an organic base. Simultaneously, triphenyl isocyanate thiophosphate is introduced for chain extension, allowing the hyperbranched block copolymer to form a stable cross-linked structure with epoxy resin. This improves flame retardancy while ensuring thermal stability. The introduction of highly branched structures and flexible segments into the epoxy resin enhances the coating's impact resistance and strength. Furthermore, the covalent network formed by the carbamate bonds generated through chain extension of triphenyl isocyanate thiophosphate and the ring-opening of epoxy groups further improves the adhesion between the coating and the substrate.

[0023] Modified ammonium polyphosphate is prepared by coating the surface of ammonium polyphosphate with polyaldehyde polyester and polyamino polyether. The polyaldehyde polyester is prepared by reacting terminal hydroxyl hyperbranched polyester with aldehyde-modified polyacrylic acid, the aldehyde-modified polyacrylic acid is prepared by polymerizing acrylic acid with acrolein, and the polyamino polyether is prepared by reacting epichlorohydrin, dodecyl alcohol polyether and ammonia. The polyaldehyde polyester and polyamino polyether form a stable cross-linked network on the surface of ammonium polyphosphate, which further improves the flame retardancy and adhesion of the coating. Detailed Implementation

[0024] The present invention will be specifically described below through embodiments. It should be noted that the following embodiments are only used to further illustrate the present invention and should not be construed as limiting the scope of protection of the present invention. Those skilled in the art can make some non-essential improvements and adjustments to the present invention based on the above description. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those skilled in the art.

[0025] The epoxy resin used in this invention is bisphenol A epoxy resin.

[0026] To more clearly illustrate the method provided by the present invention, the following examples will be used to describe in detail the various test methods for the epoxy resin-based fire-retardant and heat-insulating coatings prepared in the examples and comparative examples:

[0027] Oxygen Index: The epoxy resin-based fireproof and heat-insulating coating was sprayed onto the tinplate surface and cured at 120℃ for 5 hours. The coating thickness was 40μm. The oxygen index was tested in accordance with GB / T2406.

[0028] Impact strength: The epoxy resin-based fireproof and heat-insulating coating was placed in a mold and cured at 120℃ for 5 hours. The coating thickness was 40μm. The impact strength was tested in accordance with GB / T2567.

[0029] Thermal stability: The epoxy resin-based fireproof and heat-insulating coating was sprayed onto the tinplate surface and cured at 120℃ for 5 hours. The coating thickness was 40μm. The glass transition temperature was tested in accordance with GB / T19466.

[0030] Adhesion: The epoxy resin-based fireproof and heat-insulating coating is sprayed onto the surface of the steel part, cured at 120℃ for 5 hours, with a coating thickness of 40μm, and the maximum tensile force during the destructive test is determined according to GB / T5210.

[0031] Example 1

[0032] In this embodiment, the components and weight proportions of the epoxy resin-based fireproof and heat-insulating coating are as follows: 20 parts epoxy resin base material, 50 parts flame retardant, 100 parts expanded perlite, 2 parts glass fiber, 10 parts film-forming agent alcohol ester dodecyl, 2 parts curing agent polyamide, and 1 part defoamer nonylphenol polyoxyethylene ether. The flame retardant includes modified ammonium polyphosphate and melamine in a mass ratio of 5:1.

[0033] The preparation method of the epoxy resin-based fireproof and heat-insulating coating in this embodiment is as follows:

[0034] S1. Under a nitrogen atmosphere, ethylene, hydroxyethyl acrylate, catalyst di-(2,6-dimethylphenyl)hexanediimide nickel bromide, and toluene were mixed in a mass ratio of 1:0.08:0.002:3. The mixture was heated to 30°C and the pressure was 0.5 MPa. The reaction was carried out for 2 hours. Then, an ethanol solution of sodium hydroxide with a mass fraction of 20% (20 times the mass of ethylene) was added, and the reaction was continued for 30 minutes. The mixture was filtered and washed three times successively with methanol and deionized water. The mixture was then dried under vacuum at 60°C to obtain hydroxyl hyperbranched polyethylene. Under a nitrogen atmosphere, p-dioxanone and butanediol were mixed in a mass ratio of 20:1. The mixture was heated to 80°C and stirred until homogeneous. Then, stannous octoate catalyst with a mass fraction of 2% (0.3 times the mass of p-dioxanone) was added. A toluene solution was reacted for 48 hours, cooled to room temperature, and pulverized to obtain a hydroxyl-terminated poly(p-dioxane). Under a nitrogen atmosphere, hydroxyl-terminated hyperbranched polyethylene, hydroxyl-terminated poly(p-dioxane), and tetrahydrofuran were mixed at a mass ratio of 0.6:0.4:3 and stirred until homogeneous. Then, a 3% tetrahydrofuran solution of dibutyltin dilaurate was added dropwise at a rate of 1 ml / min, at a mass ratio of 0.08 times that of the hydroxyl-terminated hyperbranched polyethylene. The reaction was continued with stirring for 15 min. Then, a 0.4-times mass ratio of triphenyl isocyanate thiophosphate was added, the temperature was raised to 60 °C, and the reaction was carried out for 6 hours. The reaction was quenched with glacial acetic acid, precipitated with methanol, filtered, and washed three times with methanol. The mixture was then dried under vacuum at 60 °C to obtain a hyperbranched block copolymer.

[0035] S2. Epoxy resin and hyperbranched block copolymer are mixed at a mass ratio of 10:1, heated to 60°C, stirred at 400 rpm for 30 min, cooled to 48°C, and methyl hexahydrophthalic anhydride curing agent (6 times the mass of epoxy resin) is added. The mixture is stirred and reacted for 8 min. Then, 2,4,6-tris(dimethylaminomethyl)phenol accelerator (0.01 times the mass of epoxy resin) is added. The mixture is stirred and reacted for 8 min. Vacuum degassing is performed, the temperature is raised to 80°C, and the reaction is carried out for 2 h. The temperature is raised to 120°C, and the reaction is carried out for 2 h. The temperature is raised to 50°C, and the reaction is carried out for 1 h to obtain epoxy resin base material.

[0036] S3. Under a nitrogen atmosphere, acrylic acid and deionized water were mixed in a 1:1 mass ratio and stirred until dissolved. The pH was adjusted to 6.5 with 30% sodium hydroxide. Acrolein (0.4 times the mass of acrylic acid) and ammonium persulfate (0.01 times the mass of acrylic acid) were added. The mixture was heated to 50°C and reacted for 8 hours. The pH was adjusted to 2.0 with hydrochloric acid, and the mixture was precipitated with acetone. After dissolving in deionized water, the precipitate was precipitated again with acetone. Finally, the mixture was vacuum dried at 40°C to obtain aldehyde-modified polyacrylic acid. Aldehyde-modified polyacrylic acid, ethylene glycol, p-toluenesulfonic acid, and dimethyl sulfoxide were mixed in a 2:1:0.02:4 mass ratio and heated to 50°C. The reaction was carried out at 8℃ for 2 hours. Then, 1.1 times the mass of aldehyde-modified polyacrylic acid terminal hydroxyl hyperbranched polyester and 0.001 times the mass of aldehyde-modified polyacrylic acid catalyst 4-dimethylaminopyridine were added. The temperature was lowered to 48℃, and 0.22 times the mass of aldehyde-modified polyacrylic acid 30% N,N'-dicyclohexylcarbodiimide dimethyl sulfoxide solution was added dropwise at a rate of 1 ml / min. The temperature was raised to 78℃ and the reaction was carried out for 8 hours. Then, 1 times the mass of aldehyde-modified polyacrylic acid 0.03% hydrochloric acid was added, the temperature was lowered to 38℃ and the reaction was carried out for 3 hours. The reaction was dialyzed and freeze-dried at -40℃ to obtain polyaldehyde polyester.

[0037] S4. Under a nitrogen atmosphere, dodecyl alcohol polyether and DMC catalyst were mixed at a mass ratio of 10:0.1, heated to 115°C, and epichlorohydrin (1 times the mass of dodecyl alcohol polyether) was added dropwise at a rate of 1 ml / min. The mixture was then heated to 125°C and reacted for 5 h. After vacuum distillation, ammonia solution with a mass fraction of 25% (2 times the mass of dodecyl alcohol polyether) and toluene (0.4 times the mass of dodecyl alcohol polyether) were added. The mixture was heated to 50°C and reacted for 3 h. The mixture was separated and washed three times with deionized water, and then obtained by rotary evaporation. Polyamino polyether: Ammonium polyphosphate, ethanol, and deionized water were mixed in a mass ratio of 1:2:1 and ultrasonicated at 40 kHz for 20 min. Then, 0.2 times the mass of polyaldehyde polyester (based on the mass of ammonium polyphosphate) was added, the mixture was heated to 60 °C, and reacted for 6 h. Next, 0.1 times the mass of polyamino polyether (based on the mass of ammonium polyphosphate) and 0.005 times the mass of p-toluenesulfonic acid (based on the mass of ammonium polyphosphate) were added, the mixture was heated to 80 °C, and reacted for 8 h. After cooling, the mixture was centrifuged, washed three times with ethanol, and vacuum dried at 60 °C to obtain modified ammonium polyphosphate.

[0038] S5. By weight, the modified ammonium polyphosphate and melamine are mixed to prepare the flame retardant; the epoxy resin base material and film-forming agent are mixed and added to the reactor, stirred at 600 rpm for 8 min, heated to 50°C, the flame retardant is added, dispersed at 1000 rpm for 20 min, expanded perlite and glass fiber are added, stirred at 300 rpm for 10 min, defoamer and curing agent are added, stirring is continued for 5 min, and vacuum degassing is performed to obtain the epoxy resin-based fireproof and heat-insulating coating.

[0039] Example 2

[0040] In this embodiment, the components and weight parts of the epoxy resin-based fireproof and heat-insulating coating are as follows: 25 parts epoxy resin base, 60 parts flame retardant, 150 parts expanded perlite, 3 parts glass fiber, 20 parts film-forming agent 12-ol ester, 4 parts curing agent polyamide, and 2 parts defoamer nonylphenol polyoxyethylene ether. The flame retardant includes modified ammonium polyphosphate and melamine in a mass ratio of 5:1.5.

[0041] The preparation method of the epoxy resin-based fireproof and heat-insulating coating in this embodiment is as follows:

[0042] S1. Under a nitrogen atmosphere, ethylene, hydroxyethyl acrylate, catalyst di-(2,6-dimethylphenyl)hexanediimide nickel bromide, and toluene were mixed in a mass ratio of 1:0.11:0.003:4. The mixture was heated to 35°C and the pressure was 1.0 MPa. The reaction was carried out for 4 hours. Then, an ethanol solution of sodium hydroxide with a mass fraction of 23% (25 times the mass of ethylene) was added, and the reaction was continued for 40 minutes. The mixture was filtered and washed four times successively with methanol and deionized water. The mixture was then dried under vacuum at 70°C to obtain hydroxyl hyperbranched polyethylene. Under a nitrogen atmosphere, p-dioxanone and butanediol were mixed in a mass ratio of 30:2. The mixture was heated to 105°C and stirred until homogeneous. Then, stannous octoate catalyst with a mass fraction of 3% (0.45 times the mass of p-dioxanone) was added. A toluene solution was reacted for 64 h, cooled to room temperature, and pulverized to obtain a hydroxyl-terminated poly(p-dioxane). Under a nitrogen atmosphere, hydroxyl-terminated hyperbranched polyethylene, hydroxyl-terminated poly(p-dioxane), and tetrahydrofuran were mixed at a mass ratio of 0.6:0.5:3 and stirred until homogeneous. Then, a tetrahydrofuran solution of 4% dibutyltin dilaurate, with a mass ratio of 0.09 times that of the hydroxyl-terminated hyperbranched polyethylene, was added dropwise at a rate of 2 ml / min. The reaction was continued for 17 min with stirring. Then, a triphenyl isocyanate thiophosphate, with a mass ratio of 0.5 times that of the hydroxyl-terminated hyperbranched polyethylene, was added. The temperature was raised to 70 °C and the reaction was carried out for 6.5 h. The reaction was quenched with glacial acetic acid, precipitated with methanol, filtered, washed four times with methanol, and dried under vacuum at 65 °C to obtain a hyperbranched block copolymer.

[0043] S2. Epoxy resin and hyperbranched block copolymer are mixed at a mass ratio of 10:2, heated to 70℃, stirred at 500 rpm for 35 min, cooled to 50℃, and methyl hexahydrophthalic anhydride curing agent (6.5 times the mass of epoxy resin) is added. The mixture is stirred and reacted for 12 min. Then, 2,4,6-tris(dimethylaminomethyl)phenol accelerator (0.02 times the mass of epoxy resin) is added. The mixture is stirred and reacted for 9 min. Vacuum degassing is performed, the temperature is raised to 81℃, and the reaction is carried out for 2.5 h. The temperature is raised to 121℃, and the reaction is carried out for 2 h. The temperature is raised to 51℃, and the reaction is carried out for 1.5 h to obtain epoxy resin base material.

[0044] S3. Under a nitrogen atmosphere, acrylic acid and deionized water were mixed at a mass ratio of 1:1.5, stirred and dissolved, and the pH was adjusted to 7.0 with 30% sodium hydroxide. Acrolein (0.6 times the mass of acrylic acid) and ammonium persulfate (0.02 times the mass of acrylic acid) were added, the mixture was heated to 55°C, and reacted for 10 hours. The pH was adjusted to 2.1 with hydrochloric acid, and the mixture was precipitated with acetone. After dissolving in deionized water, the precipitate was precipitated again with acetone. Finally, the mixture was vacuum dried at 45°C to obtain aldehyde-modified polyacrylic acid. Aldehyde-modified polyacrylic acid, ethylene glycol, p-toluenesulfonic acid, and dimethyl sulfoxide were mixed at a mass ratio of 2:1.5:0.025:4.5 and heated to 60°C. After reacting for 2.5 h, 1.15 times the mass of aldehyde-modified polyacrylic acid was added to the terminal hydroxyl hyperbranched polyester, and 0.0015 times the mass of aldehyde-modified polyacrylic acid was added to the catalyst 4-dimethylaminopyridine. The temperature was lowered to 50 °C, and 0.23 times the mass of aldehyde-modified polyacrylic acid was added dropwise to a 40% N,N'-dicyclohexylcarbodiimide dimethyl sulfoxide solution at a rate of 2 ml / min. The temperature was raised to 80 °C, and the reaction was carried out for 8.5 h. 1.1 times the mass of aldehyde-modified polyacrylic acid was added to a 0.035% hydrochloric acid solution, and the temperature was lowered to 40 °C, and the reaction was carried out for 3.5 h. The reaction was dialyzed and freeze-dried at -50 °C to obtain polyaldehyde polyester.

[0045] S4. Under a nitrogen atmosphere, dodecyl alcohol polyether and DMC catalyst were mixed at a mass ratio of 10:0.15, heated to 118°C, and epichlorohydrin (1.5 times the mass of dodecyl alcohol polyether) was added dropwise at a rate of 2 ml / min. The mixture was then heated to 130°C and reacted for 5.5 h. After vacuum distillation, 2.5 times the mass of 26% ammonia and 0.5 times the mass of dodecyl alcohol polyether toluene were added. The mixture was then heated to 51°C and reacted for 3.5 h. The mixture was separated and washed four times with deionized water, and then rotary evaporated. Polyamino polyether was prepared by mixing ammonium polyphosphate, ethanol, and deionized water at a mass ratio of 1:2.5:1 and sonicating at 50 kHz for 25 min. Then, 0.25 times the mass of ammonium polyphosphate and polyaldehyde polyester were added, and the mixture was heated to 61 °C and reacted for 7 h. Next, 0.15 times the mass of ammonium polyphosphate and 0.006 times the mass of ammonium polyphosphate and p-toluenesulfonic acid catalyst were added, and the mixture was heated to 81 °C and reacted for 9 h. After cooling, the mixture was centrifuged, washed four times with ethanol, and dried under vacuum at 65 °C to obtain modified ammonium polyphosphate.

[0046] S5. By weight, the modified ammonium polyphosphate and melamine are mixed to prepare the flame retardant; the epoxy resin base material and film-forming agent are mixed and added to the reactor, stirred at 700 rpm for 9 min, heated to 55℃, the flame retardant is added, dispersed at 1500 rpm for 25 min, expanded perlite and glass fiber are added, stirred at 400 rpm for 12 min, defoamer and curing agent are added, stirring is continued for 7 min, and vacuum degassing is performed to obtain the epoxy resin-based fireproof and heat-insulating coating.

[0047] Example 3

[0048] In this embodiment, the components and weight proportions of the epoxy resin-based fireproof and heat-insulating coating are as follows: 30 parts epoxy resin base, 70 parts flame retardant, 200 parts expanded perlite, 4 parts glass fiber, 30 parts film-forming agent 12-ol ester, 5 parts curing agent polyamide, and 3 parts defoamer nonylphenol polyoxyethylene ether. The flame retardant includes modified ammonium polyphosphate and melamine in a mass ratio of 5:2.

[0049] The preparation method of the epoxy resin-based fireproof and heat-insulating coating in this embodiment is as follows:

[0050] S1. Under a nitrogen atmosphere, ethylene, hydroxyethyl acrylate, catalyst di-(2,6-dimethylphenyl)hexanediimide nickel bromide, and toluene were mixed in a mass ratio of 1:0.14:0.004:5, heated to 40°C, and reacted at a pressure of 1.5 MPa for 6 hours. Then, an ethanol solution of sodium hydroxide (25% by mass) at 30 times the mass of ethylene was added, and the reaction was continued for 50 minutes. The mixture was filtered and washed five times successively with methanol and deionized water, and then dried under vacuum at 80°C to obtain hydroxyl hyperbranched polyethylene. Under a nitrogen atmosphere, p-dioxanone and butanediol were mixed in a mass ratio of 40:3, heated to 110°C, and stirred until homogeneous. Then, octanoic acid ester catalyst (4% by mass) at 0.6 times the mass of p-dioxanone was added. A tin-toluene solution was reacted for 72 hours, cooled to room temperature, and pulverized to obtain a hydroxyl-terminated poly(p-dioxane). Under a nitrogen atmosphere, hydroxyl-terminated hyperbranched polyethylene, hydroxyl-terminated poly(p-dioxane), and tetrahydrofuran were mixed at a mass ratio of 0.6:0.6:3 and stirred until homogeneous. Then, a 5% tetrahydrofuran solution of dibutyltin dilaurate was added dropwise at a rate of 3 ml / min, equal to 0.1 times the mass of the hydroxyl-terminated hyperbranched polyethylene. The reaction was continued for 20 minutes, followed by the addition of 0.6 times the mass of the hydroxyl-terminated hyperbranched polyethylene, and the mixture was heated to 80°C and reacted for 7 hours. The reaction was quenched with glacial acetic acid, precipitated with methanol, filtered, washed five times with methanol, and dried under vacuum at 70°C to obtain a hyperbranched block copolymer.

[0051] S2. Epoxy resin and hyperbranched block copolymer are mixed at a mass ratio of 10:3, heated to 80℃, stirred at 600 rpm for 40 min, cooled to 52℃, methyl hexahydrophthalic anhydride curing agent (7 times the mass of epoxy resin) is added, and stirring is continued for 15 min. Then, 2,4,6-tris(dimethylaminomethyl)phenol accelerator (0.03 times the mass of epoxy resin) is added, and stirring is continued for 10 min. Vacuum degassing is performed, the temperature is raised to 82℃, and the reaction is carried out for 3 h. The temperature is raised to 122℃, and the reaction is continued for 2 h. The temperature is raised to 52℃, and the reaction is continued for 2 h to obtain epoxy resin base material.

[0052] S3. Under a nitrogen atmosphere, acrylic acid and deionized water were mixed at a mass ratio of 1:2, stirred and dissolved, and the pH was adjusted to 7.5 with 30% sodium hydroxide. Acrolein (0.8 times the mass of acrylic acid) and ammonium persulfate (0.03 times the mass of acrylic acid) were added, the temperature was raised to 60°C, and the reaction was carried out for 12 hours. The pH was adjusted to 2.2 with hydrochloric acid, and then precipitated with acetone. The precipitate was dissolved in deionized water and then precipitated with acetone again. Finally, the mixture was vacuum dried at 50°C to obtain aldehyde-modified polyacrylic acid. Aldehyde-modified polyacrylic acid, ethylene glycol, p-toluenesulfonic acid, and dimethyl sulfoxide were mixed at a mass ratio of 2:2:0.03:5 and heated to 62°C. The reaction was carried out at ℃ for 3 hours. Then, 1.2 times the mass of aldehyde-modified polyacrylic acid terminal hydroxyl hyperbranched polyester and 0.002 times the mass of aldehyde-modified polyacrylic acid catalyst 4-dimethylaminopyridine were added. The temperature was lowered to 52℃, and 0.24 times the mass of aldehyde-modified polyacrylic acid 50% N,N'-dicyclohexylcarbodiimide dimethyl sulfoxide solution was added dropwise at a rate of 3 ml / min. The temperature was raised to 82℃ and the reaction was carried out for 9 hours. Then, 1.2 times the mass of aldehyde-modified polyacrylic acid 0.04% hydrochloric acid was added, the temperature was lowered to 42℃ and the reaction was carried out for 4 hours. The reaction was dialyzed and freeze-dried at -60℃ to obtain polyaldehyde polyester.

[0053] S4. Under a nitrogen atmosphere, dodecyl alcohol polyether and DMC catalyst were mixed at a mass ratio of 10:0.2, heated to 120°C, and epichlorohydrin (2 times the mass of dodecyl alcohol polyether) was added dropwise at a rate of 3 ml / min. The mixture was then heated to 135°C and reacted for 6 h. After vacuum distillation, ammonia solution with a mass fraction of 28% (3 times the mass of dodecyl alcohol polyether) and toluene (0.6 times the mass of dodecyl alcohol polyether) were added. The mixture was heated to 52°C and reacted for 4 h. The mixture was separated and washed 5 times with deionized water. The final product was obtained by rotary evaporation. Amino polyether: Ammonium polyphosphate, ethanol, and deionized water were mixed in a mass ratio of 1:3:1 and ultrasonicated at 60 kHz for 30 min. Then, 0.3 times the mass of polyaldehyde polyester was added, the temperature was raised to 62 °C, and the reaction was carried out for 8 h. Next, 0.2 times the mass of polyamino polyether and 0.007 times the mass of p-toluenesulfonic acid catalyst were added, the temperature was raised to 82 °C, and the reaction was carried out for 10 h. After cooling, the mixture was centrifuged, washed 5 times with ethanol, and vacuum dried at 70 °C to obtain modified ammonium polyphosphate.

[0054] S5. By weight, the modified ammonium polyphosphate and melamine are mixed to prepare the flame retardant; the epoxy resin base material and film-forming agent are mixed and added to the reactor, stirred at 800 rpm for 10 min, heated to 60℃, the flame retardant is added, dispersed at 2000 rpm for 30 min, expanded perlite and glass fiber are added, stirred at 500 rpm for 13 min, defoamer and curing agent are added, stirring is continued for 8 min, and vacuum degassing is performed to obtain the epoxy resin-based fireproof and heat-insulating coating.

[0055] Comparative Example 1

[0056] The preparation method of Comparative Example 1 is the same as that of Example 2. The difference between this epoxy resin-based fireproof and heat-insulating coating and Example 2 is that the hyperbranched block copolymer is prepared by reacting hydroxyl hyperbranched polyethylene with triphenyl isocyanate thiophosphate.

[0057] Comparative Example 2

[0058] The preparation method of Comparative Example 2 is the same as that of Example 2. The difference between this epoxy resin-based fireproof and heat-insulating coating and Example 2 is that the hyperbranched block copolymer is prepared by reacting bi-hydroxyl-terminated poly(p-dioxanone) with triphenyl isocyanate thiophosphate.

[0059] Comparative Example 3

[0060] The preparation method of Comparative Example 3 is the same as that of Example 2. The difference between this epoxy resin-based fireproof and heat-insulating coating and Example 2 is that the epoxy resin base material is only epoxy resin.

[0061] Comparative Example 4

[0062] The preparation method of Comparative Example 4 is the same as that of Example 2. The difference between this epoxy resin-based fireproof and heat-insulating coating and Example 2 is that the modified ammonium polyphosphate is prepared by coating the surface of the ammonium polyphosphate with a polyaldehyde polyester.

[0063] Comparative Example 5

[0064] The preparation method of Comparative Example 5 is the same as that of Example 2. The difference between this epoxy resin-based fireproof and heat-insulating coating and Example 2 is that the modified ammonium polyphosphate is prepared by coating the surface of ammonium polyphosphate with polyamino polyether.

[0065] Comparative Example 6

[0066] The preparation method of Comparative Example 6 is the same as that of Example 2. The difference between this epoxy resin-based fire-retardant and heat-insulating coating and Example 2 is that the flame retardant only includes ammonium polyphosphate and melamine.

[0067] Example of effect

[0068] Table 1 below shows the performance test results of the epoxy resin-based fireproof and heat-insulating coatings prepared in the examples and comparative examples;

[0069] Table 1

[0070]

[0071] As can be seen from the performance data comparison in Table 1, the epoxy resin-based fireproof and heat-insulating coating prepared by the present invention is not only lightweight, but also has excellent strength, thermal stability and adhesion.

[0072] A comparison of the experimental data from Examples 1, 2, and 3 and Comparative Examples 1, 2, and 3 reveals that using hydroxyl-terminated hyperbranched polyethylene as an initiator, under the action of an organic base, and simultaneously introducing triphenyl isocyanate thiophosphate for chain extension, allows the hyperbranched block copolymer to form a stable cross-linked structure with the epoxy resin. This improves flame retardant performance while ensuring thermal stability. Introducing highly branched structures and flexible segments into the epoxy resin enhances the coating's impact resistance and strength. Furthermore, the covalent network formed by the urethane bonds generated by the chain extension of triphenyl isocyanate thiophosphate and the ring-opening of epoxy groups further improves the adhesion between the coating and the substrate.

[0073] A comparison of the experimental data from Examples 1, 2, 3 and Comparative Examples 4, 5, and 6 reveals that the polyaldehyde polyester prepared by reacting terminal hydroxyl hyperbranched polyester with aldehyde-based polyacrylic acid, and the polyamino polyether prepared by reacting epichlorohydrin, dodecyl alcohol polyether, and ammonia water, form a stable cross-linking network on the surface of ammonium polyphosphate. This further enhances the flame retardancy and adhesion of the coating, while also increasing its hydrophobicity and ensuring the performance stability of the coating in humid environments.

[0074] Obviously, the above embodiments are merely examples to clearly illustrate the embodiments of the present invention, and are not intended to limit the embodiments of the present invention. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively list all embodiments here. However, these obvious variations or modifications derived from the spirit of the present invention are still within the protection scope of the present invention.

Claims

1. An epoxy resin-based fire-retardant and heat-insulating coating, characterized in that, The raw materials comprise the following components by weight: 20-30 parts epoxy resin base, 50-70 parts flame retardant, 100-200 parts expanded perlite, 2-4 parts glass fiber, 10-30 parts film-forming agent, 2-5 parts curing agent, and 1-3 parts defoamer; the epoxy resin base is prepared by reacting epoxy resin with a hyperbranched block copolymer; the flame retardant comprises modified ammonium polyphosphate and melamine in a mass ratio of 5:1-2; the hyperbranched block copolymer is hydroxyl hyperbranched polyethylene glycol. The hyperbranched block copolymer was prepared by reacting olefin, dihydroxylated poly(p-dioxanone), and triphenyl isocyanate thiophosphate. The preparation method of the hyperbranched block copolymer is as follows: Under a nitrogen atmosphere, hydroxyl-modified hyperbranched polyethylene, dihydroxylated poly(p-dioxanone), and tetrahydrofuran were mixed at a mass ratio of 0.6:(0.4~0.6):3, stirred until homogeneous, and then tetrahydrofuran containing 3~5% dibutyltin dilaurate was added dropwise at a rate of 1~3 ml / min, at a mass ratio of 0.08~0.1 times that of the hydroxyl-modified hyperbranched polyethylene. The solution was stirred for 15-20 minutes, and 0.4-0.6 times the mass of hydroxyl hyperbranched polyethylene triphenyl isocyanate thiophosphate was added. The temperature was raised to 60-80℃, and the reaction was carried out for 6-7 hours. The reaction was quenched with glacial acetic acid, precipitated with methanol, filtered, and washed 3-5 times with methanol. The mixture was then vacuum dried at 60-70℃ to obtain the hyperbranched block copolymer. The modified ammonium polyphosphate was prepared by mixing ammonium polyphosphate, ethanol, and deionized water at a mass ratio of 1:(2-3):1 at 40℃. The mixture was ultrasonically treated at ~60kHz for 20-30 minutes, then 0.2-0.3 times the mass of ammonium polyphosphate and polyaldehyde polyester were added. The temperature was raised to 60-62℃ and the reaction was carried out for 6-8 hours. Then, 0.1-0.2 times the mass of ammonium polyphosphate and 0.005-0.007 times the mass of ammonium polyphosphate and p-toluenesulfonic acid as a catalyst were added. The temperature was raised to 80-82℃ and the reaction was carried out for 8-10 hours. After cooling, the mixture was centrifuged, washed with ethanol 3-5 times, and vacuum dried at 60-70℃ to obtain modified ammonium polyphosphate.

2. The epoxy resin-based fireproof and heat-insulating coating according to claim 1, characterized in that, The modified ammonium polyphosphate is prepared by coating the surface of ammonium polyphosphate with a polyaldehyde polyester and a polyamino polyether; the polyaldehyde polyester is prepared by reacting a hydroxyl-terminated hyperbranched polyester with an aldehyde-modified polyacrylic acid; the aldehyde-modified polyacrylic acid is prepared by polymerizing acrylic acid with acrolein; and the polyamino polyether is prepared by reacting epichlorohydrin, dodecyl alcohol polyether and ammonia.

3. The epoxy resin-based fireproof and heat-insulating coating according to claim 1, characterized in that, The film-forming agent is 12-ol ester; the curing agent is polyamide; and the defoamer is nonylphenol polyoxyethylene ether.

4. A method for preparing an epoxy resin-based fire-retardant and heat-insulating coating according to any one of claims 1-3, characterized in that, The specific steps include the following: S1. Under a nitrogen atmosphere, hydroxyl hyperbranched polyethylene, dihydroxyl-terminated poly(p-dioxane)-co-dioxane, and tetrahydrofuran were mixed at a mass ratio of 0.6:(0.4~0.6):

3. After stirring evenly, a tetrahydrofuran solution of dibutyltin dilaurate with a mass fraction of 3~5% was added dropwise at a rate of 1~3 ml / min, which was 0.08~0.1 times the mass of the hydroxyl hyperbranched polyethylene. The reaction was continued with stirring for 15~20 min. Then, triphenyl isocyanate thiophosphate with a mass fraction of 0.4~0.6 times the mass of the hydroxyl hyperbranched polyethylene was added. The temperature was raised to 60~80℃ and the reaction was carried out for 6~7 h. The reaction was quenched with glacial acetic acid, precipitated with methanol, filtered, and washed with methanol 3~5 times. The mixture was then dried under vacuum at 60~70℃ to obtain the hyperbranched block copolymer. S2. Mix epoxy resin and hyperbranched block copolymer at a mass ratio of 10:1~3, heat to 60~80℃, stir and mix at 400~600rpm for 30~40min, cool to 48~52℃, add curing agent methylhexahydrophthalic anhydride at 6~7 times the mass of epoxy resin, continue stirring and reacting for 8~15min, then add accelerator 2,4,6-tris(dimethylaminomethyl)phenol at 0.01~0.03 times the mass of epoxy resin, continue stirring and reacting for 8~10min, degas under vacuum, heat to 80~82℃, react for 2~3h, heat to 120~122℃, continue reacting for 2h, heat to 50~52℃, continue reacting for 1~2h, to obtain epoxy resin base material; S3. Mix aldehyde-modified polyacrylic acid, ethylene glycol, p-toluenesulfonic acid, and dimethyl sulfoxide in a mass ratio of 2:(1~2):(0.02~0.03):(4~5), heat to 58~62℃, react for 2~3 hours, add 1.1~1.2 times the mass of aldehyde-modified polyacrylic acid terminal hydroxyl hyperbranched polyester, and 0.001~0.002 times the mass of aldehyde-modified polyacrylic acid catalyst 4-dimethylaminopyridine, cool to 48~52℃, and add 1~3 ml / A solution of N,N'-dicyclohexylcarbodiimide in dimethyl sulfoxide with a mass fraction of 30-50% was added dropwise at a rate of 0.22-0.24 times the mass of aldehyde-modified polyacrylic acid at a rate of min. The temperature was raised to 78-82℃ and the reaction was carried out for 8-9 hours. Then, hydrochloric acid with a mass fraction of 0.03-0.04% was added with a mass fraction of 1-1.2 times the mass of aldehyde-modified polyacrylic acid at a rate of 0.03-0.04%. The temperature was lowered to 38-42℃ and the reaction was carried out for 3-4 hours. The mixture was dialyzed and freeze-dried at -40 to -60℃ to obtain polyaldehyde-modified polyester. S4. Mix ammonium polyphosphate, ethanol, and deionized water at a mass ratio of 1:(2~3):1, sonicate at 40~60kHz for 20~30min, add 0.2~0.3 times the mass of ammonium polyphosphate and polyaldehyde polyester, heat to 60~62℃, react for 6~8h, then add 0.1~0.2 times the mass of ammonium polyphosphate and 0.005~0.007 times the mass of ammonium polyphosphate and p-toluenesulfonic acid catalyst, heat to 80~82℃, react for 8~10h, cool, centrifuge, wash with ethanol 3~5 times, and vacuum dry at 60~70℃ to obtain modified ammonium polyphosphate; S5. By weight, mix modified ammonium polyphosphate and melamine to prepare a fire-retardant coating; mix epoxy resin base material and film-forming agent and add to a reactor, stir at 600~800 rpm for 8~10 min, heat to 50~60℃, add fire-retardant coating, disperse at 1000~2000 rpm for 20~30 min, add expanded perlite and glass fiber, stir at 300~500 rpm for 10~13 min, add defoamer and curing agent, continue stirring for 5~8 min, degas under vacuum to obtain epoxy resin-based fireproof and heat-insulating coating.

5. The method for preparing an epoxy resin-based fire-retardant and heat-insulating coating according to claim 4, characterized in that, In step S1, the preparation method of hydroxyl hyperbranched polyethylene is as follows: Under a nitrogen atmosphere, ethylene, hydroxyethyl acrylate, catalyst di-(2,6-dimethylphenyl)hexamethylenediimide nickel bromide and toluene are mixed in a mass ratio of 1:(0.08~0.14):(0.002~0.004):(3~5), heated to 30~40℃, pressure 0.5~1.5MPa, and reacted for 2~6h. Then, 20~30 times the mass of ethylene is added to an ethanol solution of sodium hydroxide with a mass fraction of 20~25%, and the reaction is continued for 30~50min. The mixture is filtered and washed 3~5 times with methanol and deionized water in sequence, and then dried under vacuum at 60~80℃ to obtain hydroxyl hyperbranched polyethylene.

6. The method for preparing an epoxy resin-based fire-retardant and heat-insulating coating according to claim 4, characterized in that, In step S1, the preparation method of hydroxyl-terminated poly(p-dioxane) is as follows: under a nitrogen atmosphere, p-dioxane and butanediol are mixed at a mass ratio of (20~40):(1~3), heated to 80~110℃, stirred evenly, and then 0.3~0.6 times the mass of p-dioxane and a catalyst stannous octoate toluene solution with a mass fraction of 2~4% are added. The reaction is carried out for 48~72h, cooled to room temperature, and pulverized to obtain hydroxyl-terminated poly(p-dioxane).

7. The method for preparing an epoxy resin-based fire-retardant and heat-insulating coating according to claim 4, characterized in that, In step S3 above, the preparation method of aldehyde-based polyacrylic acid is as follows: Under a nitrogen atmosphere, acrylic acid and deionized water are mixed at a mass ratio of 1:1~2, stirred and dissolved, and the pH is adjusted to 6.5~7.5 with 30% sodium hydroxide. Acrolein and ammonium persulfate (0.01~0.03 times the mass of acrylic acid) are added. The temperature is raised to 50~60℃ and reacted for 8~12 hours. The pH is adjusted to 2.0~2.2 with hydrochloric acid, and then precipitated with acetone. After dissolving in deionized water, it is precipitated with acetone again. Finally, it is vacuum dried at 40~50℃ to obtain aldehyde-based polyacrylic acid.

8. The method for preparing an epoxy resin-based fire-retardant and heat-insulating coating according to claim 4, characterized in that, In step S4, the preparation method of polyamino polyether is as follows: Under a nitrogen atmosphere, dodecyl alcohol polyether and DMC catalyst are mixed at a mass ratio of 10:0.1~0.2, heated to 115~120℃, and epichlorohydrin with a mass of 1~2 times the mass of dodecyl alcohol polyether is added dropwise at a rate of 1~3 ml / min. The temperature is raised to 125~135℃, and the reaction is carried out for 5~6 h. After vacuum distillation, ammonia water with a mass fraction of 25~28% and toluene with a mass fraction of 0.4~0.6 times the mass of dodecyl alcohol polyether are added. The temperature is raised to 50~52℃, and the reaction is carried out for 3~4 h. The mixture is separated and washed 3~5 times with deionized water. Polyamino polyether is obtained by rotary evaporation.

9. The application of the epoxy resin-based fire-retardant and heat-insulating coating according to claim 1, characterized in that, The epoxy resin-based fireproof and heat-insulating coating is used in the petrochemical and construction industries.

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