Battery pack fireproof and heat insulation coating and preparation method thereof

Abstract

The application discloses a battery pack fireproof and heat-insulating coating and a preparation method thereof, and relates to the technical field of fireproof coatings. The battery pack fireproof and heat-insulating coating prepared by the application comprises a composite flame-retardant charring agent, modified phenolic resin, fillers, a silane coupling agent and a defoaming agent. The modified phenolic resin is prepared by the reaction of double-end hydroxyl polyphenyl ether, amino-phenolic resin and polythioacetal. The double-end hydroxyl polyphenyl ether is prepared by the reaction of 2,6-dimethylphenol and tetramethyl bisphenol A. The polythioacetal is prepared by the polymerization of 1,3-dimercapto-2-propanol and cinnamaldehyde. The thermal stability is improved, and the coating has the ability of self-repairing. The composite flame-retardant charring agent is prepared by the reaction of a sulfonamide piperazine compound, 4,4'-dimercaptodiphenyl sulfide and diamino diphenyl methane modified ammonium polyphosphate. The sulfonamide piperazine compound is prepared by the reaction of chlorosulfonyl isocyanate and piperazine, and then the reaction with chloroacetyl chloride. The carbonization property and thermal stability of the coating are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of fireproof coating, in particular to a battery pack fireproof and heat insulation coating and a preparation method thereof. BACKGROUND

[0002] The power battery system relates to meeting the power requirements and other designs of the whole vehicle as a prerequisite, while considering the internal structure and safety and management design of the battery system itself. The battery pack shell, as the carrier of the battery module, plays a key role in the safe operation and protection of the battery module. The battery pack is the core energy source of new energy vehicles, providing driving power for the whole vehicle, which is mainly composed of a shell envelope.

[0003] The battery shell is generally installed at the lower part of the vehicle body and is mainly used for protecting the lithium battery from damage when subjected to external impact and extrusion. Due to its special function, its surface is treated for corrosion resistance, insulation and flame retardation. Therefore, the present application studies and prepares a battery pack fireproof and heat insulation coating with excellent flame retardation, heat insulation and thermal stability. SUMMARY

[0004] The present application relates to the technical field of fireproof coating, in particular to a battery pack fireproof and heat insulation coating and a preparation method thereof.

[0005] A technical solution provided by the present application to solve the above technical problems is: a battery pack fireproof and heat insulation coating, comprising the following raw material components in parts by weight: 45-55 parts of a composite flame-retardant charring agent, 100 parts of a modified phenolic resin, 12-18 parts of a filler, 1-3 parts of a silane coupling agent, and 0.5-1 part of a defoaming agent; the modified phenolic resin is prepared by reaction of double-end hydroxyl polyphenyl ether, amino phenolic resin and polythioacetal; and the composite flame-retardant charring agent is prepared by reaction of a sulfonamide piperazine compound, 4,4'-dimercaptodiphenyl sulfide and diamino diphenyl methane modified ammonium polyphosphate.

[0006] Preferably, the modified phenolic resin is prepared by reaction of double-end hydroxyl polyphenyl ether, amino phenolic resin and polythioacetal; the double-end hydroxyl polyphenyl ether is prepared by reaction of 2,6-dimethylphenol and tetramethyl bisphenol A; and the polythioacetal is prepared by polymerization of 1,3-dimercapto-2-propanol and cinnamaldehyde.

[0007] Preferably, the composite flame-retardant charring agent is prepared by reaction of a sulfonamide piperazine compound, 4,4'-dimercaptodiphenyl sulfide and diamino diphenyl methane modified ammonium polyphosphate; and the sulfonamide piperazine compound is prepared by reaction of chlorosulfonyl isocyanate and piperazine, followed by reaction with chloroacetyl chloride.

[0008] Preferably, the filler is a mixture of equal mass of zinc borate and nano-silicon dioxide; the silane coupling agent is KH-550; and the defoaming agent is polydimethylsiloxane.

[0009] Preferably, the preparation method of the fireproof and thermal insulation coating for battery pack comprises the following specific steps:

[0010] S1. Mix the double-end hydroxyl polyphenyl ether with toluene at a mass ratio of 1:0.5-1, heat to 60-70℃, stir uniformly, then add amino phenolic resin with a mass of 0.3-0.5 times that of the double-end hydroxyl polyphenyl ether, continue to react for 1-2h, then add polythioacetal with a mass of 0.2-0.4 times that of the double-end hydroxyl polyphenyl ether and catalyst nickel chloride hexahydrate with a mass of 0.002-0.004 times that of the double-end hydroxyl polyphenyl ether, heat to 80-100℃, react for 2-4h, adjust the pH to 8-9 with triethylamine, add crosslinking agent divinylbenzene with a mass of 0.05-0.1 times that of the double-end hydroxyl polyphenyl ether, heat to 120-140℃, react for 3-5h, precipitate with methanol, filter and wash with deionized water and ethanol for 3-5 times, and dry at 60-70℃ under vacuum to obtain the modified phenolic resin;

[0011] S2. Mix the diamino diphenyl methane modified ammonium polyphosphate with anhydrous N-methyl pyrrolidone at a mass ratio of 2-3:5, heat to 60-70℃, stir uniformly, then cool to 40-50℃, add 4,4'-dimercaptodiphenyl sulfide with a mass of 0.5-0.6 times that of the diamino diphenyl methane modified ammonium polyphosphate, continue to react for 1-2h, then add sulfonamide compound with a mass of 1.6-1.8 times that of the diamino diphenyl methane modified ammonium polyphosphate, and catalyst dibutyltin dilaurate with a mass of 0.01-0.02 times that of the diamino diphenyl methane modified ammonium polyphosphate, heat to 70-80℃, react for 3-4h, precipitate with deionized water after quenching with methanol, wash with deionized water and ethanol for 3-5 times, and dry at 60-70℃ under vacuum to obtain the composite flame-retardant charring agent;

[0012] S3. Mix the composite flame-retardant charring agent, modified phenolic resin, filler, silane coupling agent and defoaming agent by weight parts, and crush to obtain the fireproof and thermal insulation coating for battery pack.

[0013] Preferably, in the step S1, the preparation method of the double-end hydroxyl polyphenyl ether is as follows: mix 2,6-dimethylphenol, tetramethyl bisphenol A, cuprous bromide, di-n-butylamine and toluene at a mass ratio of 10:0.5-3:0.003-0.005:0.004-0.006:30, heat to 45-65℃, pass oxygen at a rate of 0.5-1.0ml / min until the reaction is completed, stir at 200-400rpm for 2-3h, add trisodium nitrilotriacetate with an equal molar mass of cuprous bromide, heat to 70-80℃, continue to react for 40-50min, stand to separate the liquid, then precipitate with methanol, filter and dry at 60-70℃ under vacuum to obtain the double-end hydroxyl polyphenyl ether.

[0014] Preferably, in the step S1, the amino phenolic resin is prepared by the following method: a 37% mass fraction formaldehyde solution is placed in a reaction kettle, the pH is adjusted to 8.5-9.0 by sodium hydroxide, 0.6-0.8 times the mass of the formaldehyde solution of phenol is added, the temperature is raised to 73-75°C, the reaction is stirred at 200-400 rpm for 30-45 min, 0.2-0.4 times the mass of the total mass of phenol of melamine is added in 2-3 times with an interval of 15 min, the reaction is continued for 50-60 min, the pH is adjusted to 4.5-6.0 by hydrochloric acid, the temperature is raised to 80-90°C, the reaction is continued for 2-3 h, the temperature is cooled to room temperature, vacuum dehydration is carried out at 60-80°C, and the amino phenolic resin is prepared.

[0015] Preferably, in the step S1, the polythioacetal is prepared by the following method: 1,3-dimercapto-2-propanol and cinnamaldehyde are mixed in a mass ratio, placed in an ice bath, 0.06-0.08 times the mass of the cinnamaldehyde of a 28-32% mass fraction hydrochloric acid is added at a rate of 1-3 ml / min, the reaction is stirred at 200-400 rpm for 25-35 min, washed with deionized water for 3-5 times, dissolved in tetrahydrofuran, precipitated with n-hexane, purified by gel column with tetrahydrofuran as the eluent, and vacuum dried at room temperature to prepare the polythioacetal.

[0016] Preferably, in the step S2, the sulfonazide compound is prepared by the following method: piperazine is mixed with dichloromethane in a mass ratio of 1:22-25, piperazine is added at a rate of 8-10 ml / min, the reaction is carried out for 1.5-2.5 h, the reaction is quenched with ice water, the reaction is separated, dried with anhydrous magnesium sulfate, concentrated under reduced pressure, transferred to 8-10 times the mass of the piperazine of anhydrous acetonitrile, placed at 0--10°C, 3.4-3.5 times the mass of the piperazine of triethylamine and 3.1-3.2 times the mass of the piperazine of chloroacetyl chloride are added at a rate of 8-10 ml / min, the reaction is continued for 3-4 h, filtered and concentrated under pressure, and column chromatography is carried out with dichloromethane and methanol in a volume ratio of 20:1 as the eluent to prepare the sulfonazide compound.

[0017] Preferably, in the step S2, the diamino diphenyl methane modified ammonium polyphosphate is prepared by the following method: ethanol and deionized water are mixed in a mass ratio of 20:1-2, the temperature is raised to 90-92°C, 0.04-0.05 times the mass of the ethanol of molten diamino diphenyl methane and 0.08-0.1 times the mass of the ethanol of ammonium polyphosphate are added after the mixture is uniformly stirred, the temperature is lowered to 58-62°C, the reaction is carried out for 4-6 h, the mixture is cooled to room temperature, filtered, dried, and ground to prepare the diamino diphenyl methane modified ammonium polyphosphate.

[0018] Compared with the prior art, the present application has the following beneficial effects:

[0019] The battery pack fireproof and heat insulation coating prepared by the application comprises a composite flame-retardant charring agent, modified phenolic resin, filler, silane coupling agent and defoaming agent.

[0020] The modified phenolic resin is prepared by reaction of double-end hydroxyl polyphenyl ether, amino-phenolic resin and polythioacetal, the double-end hydroxyl polyphenyl ether is prepared by reaction of 2,6-dimethylphenol and tetramethyl bisphenol A, and the polythioacetal is prepared by polymerization of 1,3-dimercapto-2-propanol and cinnamaldehyde, the introduction of phosphorus, nitrogen and sulfur can synergistically flame-retard with the composite flame-retardant charring agent, the flexible chain segment of the polythioacetal can also buffer thermal stress and improve thermal stability, and the modified phenolic resin with the double-end hydroxyl polyphenyl ether not only has high temperature resistance and mechanical strength, but also has self-repairing ability due to the dynamic crosslinking points introduced by the Schiff base reaction of the polythioacetal.

[0021] The composite flame-retardant charring agent is prepared by modification of ammonium polyphosphate by a sulfonyl piperazine compound, 4,4'-dimercaptodiphenyl sulfide and diaminodiphenyl methane, the sulfonyl piperazine compound is prepared by reaction of chlorosulfonylisocyanate and piperazine, and then by reaction with chloroacetyl chloride, the sulfide is generated by reaction of the sulfonyl piperazine compound and mercapto, and then the ammonium polyphosphate with amino introduced by ion exchange reaction is reacted, which enhances the compatibility of the sulfide with the resin matrix, the synergistic effect of multiple elements also provides abundant acid source and gas source, the sulfur oxide generated by oxidation of the sulfide bond at high temperature is combined with the decomposition product of the ammonium polyphosphate to form a dense and high-strength expanded carbon layer, which effectively blocks heat radiation and oxygen diffusion, thereby significantly improving the carbonization and thermal stability of the coating. DETAILED DESCRIPTION

[0022] The application will be described in detail by the following examples, it is necessary to point out that the following examples are only used to further illustrate the application, and cannot be understood as limiting the protection scope of the application, the skilled in the art can make some non-essential improvements and adjustments to the application according to the above content of the application. Unless otherwise defined, all professional and scientific terms used herein have the same meaning as familiar to the skilled in the art.

[0023] In order to more clearly illustrate the method provided by the application, the following examples are used to illustrate the method in detail, the index test method of the battery pack fireproof and heat insulation coating prepared in the examples and comparative examples is as follows:

[0024] Coating preparation: the battery pack fireproof and heat insulation coating prepared in the examples and comparative examples is coated on an aluminum alloy plate with a thickness of 1mm according to GB / T 1727, and the dry film thickness is 1.5mm for performance test.

[0025] Thermal stability: the coating is tested for temperature rise rate on the backfire surface under direct flame impact at 800℃ according to GB 38031.

[0026] Flame resistance: the coating is tested for oxygen index according to GB / T 2406.

[0027] Stone chip resistance: the coating is tested for stone chip resistance according to GB / T 1732 to determine whether the coating has exposed substrate.

[0028] Self-repairing property: the coating is tested for self-repairing property according to GB / T 36377 to determine the repair rate within 24 hours when the scratch width is 50 pm.

[0029] Example 1

[0030] In this example, the components and weight parts of the fireproof and thermal insulation coating for battery pack are as follows: 45 parts of composite flame-retardant charring agent, 100 parts of modified phenolic resin, 12 parts of filler, the filler being equal-mass mixed zinc borate and nano-silicon dioxide, 1 part of silane coupling agent KH-550, and 0.5 part of defoaming agent polydimethylsiloxane.

[0031] In this example, the preparation method of the fireproof and thermal insulation coating for battery pack is as follows:

[0032] S1. 2,6-dimethylphenol, tetramethyl bisphenol A, cuprous bromide, di-n-butylamine and toluene were mixed in a mass ratio of 10:0.5:0.003:0.004:30, and the temperature was raised to 45°C. Oxygen was passed at a rate of 0.5 ml / min until the end of the reaction. The reaction was stirred at 200 rpm for 2 h. An equimolar amount of nitrilotriacetic acid trisodium salt was added to the cuprous bromide. The temperature was raised to 70°C, and the reaction was continued for 40 min. After standing and separating the liquid, methanol was added for precipitation. After filtration, vacuum drying was performed at 60°C to obtain a double-end hydroxyl polyphenyl ether. A 37% mass fraction formaldehyde solution was placed in a reaction kettle. Sodium hydroxide was used to adjust the pH to 8.5. An amount of phenol equal to 0.6 times the mass of the formaldehyde solution was added. The temperature was raised to 73°C. The reaction was stirred at 200 rpm for 30 min. An amount of melamine equal to 0.2 times the mass of the phenol was added in two portions with an interval of 15 min. The reaction was continued for 50 min. Hydrochloric acid was used to adjust the pH to 4.5. The temperature was raised to 80°C. The reaction was continued for 2 h. The temperature was cooled to room temperature. Vacuum dehydration was performed at 60°C to obtain an amino phenolic resin. Under a nitrogen atmosphere, 1,3-dimercapto-2-propanol and cinnamaldehyde were mixed in equal amounts. An amount of 28% mass fraction hydrochloric acid equal to 0.06 times the mass of the cinnamaldehyde was added dropwise at a rate of 1 ml / min. The reaction was stirred at 200 rpm for 25 min. Deionized water was used for washing 3 times. The product was dissolved in tetrahydrofuran and precipitated with n-hexane. Purification was performed by gel column chromatography using tetrahydrofuran as the eluent. Vacuum drying was performed at room temperature to obtain a polythioacetal. The double-end hydroxyl polyphenyl ether and toluene were mixed in a mass ratio of 1:0.5. After uniform stirring at a temperature of 60°C, an amount of amino phenolic resin equal to 0.3 times the mass of the double-end hydroxyl polyphenyl ether was added. The reaction was continued for 1 h. An amount of polythioacetal equal to 0.2 times the mass of the double-end hydroxyl polyphenyl ether and an amount of catalyst nickel chloride hexahydrate equal to 0.002 times the mass of the double-end hydroxyl polyphenyl ether were added. The temperature was raised to 80°C. The reaction was continued for 2 h. Triethylamine was used to adjust the pH to 8. An amount of crosslinking agent divinylbenzene equal to 0.05 times the mass of the double-end hydroxyl polyphenyl ether was added. The temperature was raised to 120°C. The reaction was continued for 3 h. Methanol was added for precipitation. Filtration was performed, and the product was washed with deionized water and ethanol 3 times, respectively. Vacuum drying was performed at 60°C to obtain a modified phenolic resin.

[0033] S2. Piperazine is mixed with dichloromethane at a mass ratio of 1:22 and placed in an ice bath. Chlorosulfonyl isocyanate is added at a rate of 8 ml / min, with the amount being 1.95 times the molar mass of piperazine. The reaction is allowed to proceed for 1.5 h, after which the reaction mixture is separated by adding ice water, dried with anhydrous magnesium sulfate, and concentrated under reduced pressure. The concentrated product is transferred to anhydrous acetonitrile in an amount 8 times the mass of piperazine, and placed in a temperature range of 0 to -10℃. Triethylamine is added at a rate of 8 ml / min, with the amount being 3.4 times the mass of piperazine, followed by the addition of chloroacetyl chloride at a rate of 8 ml / min, with the amount being 3.1-3.2 times the mass of piperazine. The reaction is allowed to proceed for 3 h, after which the product is filtered and concentrated under pressure. The product is then purified by column chromatography using dichloromethane and methanol at a volume ratio of 20:1 as the eluent to obtain a sulfonylpiperazine compound. Ethanol and deionized water are mixed at a mass ratio of 20:1, and the mixture is heated to 90℃. After being stirred uniformly, fused diamino diphenyl methane is added in an amount of 0.04 times the mass of ethanol, and ammonium polyphosphate is added in an amount of 0.08 times the mass of ethanol. The mixture is cooled to 58℃ and allowed to react for 4 h. After being cooled to room temperature, the mixture is filtered and dried, and then ground to obtain diamino diphenyl methane modified ammonium polyphosphate. The diamino diphenyl methane modified ammonium polyphosphate is mixed with anhydrous N-methyl pyrrolidone at a mass ratio of 2:5, and the mixture is heated to 60℃. After being stirred uniformly, the mixture is cooled to 40℃. 4,4'-dimercaptodiphenyl sulfide is added in an amount of 0.5 times the mass of the diamino diphenyl methane modified ammonium polyphosphate, and the reaction is allowed to proceed for 1 h. Then, the sulfonylpiperazine compound is added in an amount of 1.6 times the mass of the diamino diphenyl methane modified ammonium polyphosphate, and the catalyst dibutyltin dilaurate is added in an amount of 0.01 times the mass of the diamino diphenyl methane modified ammonium polyphosphate. The mixture is heated to 70℃ and allowed to react for 3 h. After being quenched with methanol, the product is precipitated by deionized water, washed with deionized water and ethanol three times in sequence, and dried under vacuum at 60℃ to obtain a composite flame-retardant charring agent.

[0034] S3. The composite flame-retardant charring agent, modified phenolic resin, filler, silane coupling agent, and defoaming agent are mixed and ground to obtain a battery pack fireproof and heat-insulating coating.

[0035] Example 2

[0036] In this example, the components and weight fractions of the battery pack fireproof and heat-insulating coating are as follows: 50 parts of the composite flame-retardant charring agent, 100 parts of the modified phenolic resin, 16 parts of the filler, which is a mixture of zinc borate and nano-silicon dioxide in equal mass, 2 parts of the silane coupling agent KH-550, and 0.8 parts of the defoaming agent polydimethylsiloxane.

[0037] In this example, the preparation method of the battery pack fireproof and heat-insulating coating is as follows:

[0038] S1. 2,6-dimethylphenol, tetramethyl bisphenol A, cuprous bromide, di-n-butylamine and toluene were mixed in a mass ratio of 10:1.8:0.004:0.005:30, and the temperature was raised to 50°C. Oxygen was passed at a rate of 0.8 ml / min until the end of the reaction. The reaction was stirred at 300 rpm for 2.5 h. An equimolar amount of nitrilotriacetic acid trisodium salt was added to the cuprous bromide. The temperature was raised to 75°C, and the reaction was continued for 45 min. After standing and separation, methanol was added for precipitation. After filtration, the product was dried at 65°C under vacuum to obtain a double-end hydroxyl polyphenyl ether. A 37% mass fraction formaldehyde solution was placed in a reaction kettle, and the pH was adjusted to 8.8 with sodium hydroxide. An amount of phenol equal to 0.7 times the mass of the formaldehyde solution was added, and the temperature was raised to 74°C. The reaction was stirred at 300 rpm for 35 min. An amount of melamine equal to 0.3 times the mass of the phenol was added in two portions with an interval of 15 min. The reaction was continued for 55 min. The pH was adjusted to 5.5 with hydrochloric acid. The temperature was raised to 85°C, and the reaction was continued for 2.5 h. The temperature was cooled to room temperature, and the product was dehydrated under vacuum at 70°C to obtain an amino phenolic resin. Under a nitrogen atmosphere, 1,3-dimercapto-2-propanol and cinnamaldehyde were mixed in equal amounts. An amount of 30% mass fraction hydrochloric acid equal to 0.07 times the mass of the cinnamaldehyde was added dropwise at a rate of 2 ml / min. The reaction was stirred at 300 rpm for 30 min. The product was washed with deionized water four times, dissolved in tetrahydrofuran, and precipitated with n-hexane. The product was purified by gel column chromatography using tetrahydrofuran as the eluent, and dried under vacuum at room temperature to obtain a polythioacetal. The double-end hydroxyl polyphenyl ether and toluene were mixed in a mass ratio of 1:0.8. After stirring uniformly at a temperature of 65°C, an amount of amino phenolic resin equal to 0.4 times the mass of the double-end hydroxyl polyphenyl ether was added. The reaction was continued for 1.5 h. An amount of polythioacetal equal to 0.3 times the mass of the double-end hydroxyl polyphenyl ether and an amount of catalyst nickel chloride hexahydrate equal to 0.003 times the mass of the double-end hydroxyl polyphenyl ether were added. The temperature was raised to 90°C, and the reaction was continued for 3 h. The pH was adjusted to 8.5 with triethylamine. An amount of crosslinking agent divinylbenzene equal to 0.08 times the mass of the double-end hydroxyl polyphenyl ether was added. The temperature was raised to 130°C, and the reaction was continued for 4 h. The product was precipitated with methanol, filtered, and washed with deionized water and ethanol four times, respectively. The product was dried under vacuum at 65°C to obtain a modified phenolic resin.

[0039] S2. Piperazine is mixed with dichloromethane at a mass ratio of 1:24 and placed in an ice bath. Chlorosulfonyl isocyanate with a molar mass of 2 times that of piperazine is added dropwise at a rate of 9 ml / min. The reaction is carried out for 2 h, and after quenching with ice water, the mixture is separated into two layers, dried with anhydrous magnesium sulfate, and concentrated under reduced pressure. The residue is transferred to anhydrous acetonitrile with a mass of 9 times that of piperazine, placed in a -5℃ environment, and then 3.45 times the mass of piperazine of triethylamine and 3.15 times the mass of piperazine of chloroacetyl chloride are added dropwise at a rate of 9 ml / min, respectively. The reaction is continued for 3.5 h, and then the mixture is filtered and concentrated under pressure. The product, a sulfonated piperazine compound, is obtained by column chromatography using dichloromethane and methanol (20:1 by volume) as the eluent. Ethanol and deionized water are mixed at a mass ratio of 20:1.5, heated to 91℃, and stirred until uniform. Then, 0.045 times the mass of ethanol of molten diaminodiphenylmethane and 0.09 times the mass of ethanol of ammonium polyphosphate are added. The temperature is lowered to 60℃, and the reaction is carried out for 5 h. After cooling to room temperature, the mixture is filtered and dried, and then ground to obtain diaminodiphenylmethane-modified ammonium polyphosphate. The diaminodiphenylmethane-modified ammonium polyphosphate is mixed with anhydrous N-methylpyrrolidone at a mass ratio of 2.5:5, heated to 65℃, and stirred until uniform. Then, the temperature is lowered to 45℃, and 0.55 times the mass of diaminodiphenylmethane-modified ammonium polyphosphate of 4,4'-dimercaptodiphenyl sulfide is added. The reaction is continued for 1.5 h, and then 1.7 times the mass of diaminodiphenylmethane-modified ammonium polyphosphate of the sulfonated piperazine compound and 0.015 times the mass of diaminodiphenylmethane-modified ammonium polyphosphate of dibutyltin dilaurate are added. The temperature is raised to 75℃, and the reaction is carried out for 3.5 h. After quenching with methanol, the product is precipitated by deionized water, washed with deionized water and ethanol four times, respectively, and dried under vacuum at 65℃ to obtain a composite flame-retardant charring agent.

[0040] S3. The composite flame-retardant charring agent, modified phenolic resin, filler, silane coupling agent, and defoaming agent are mixed and ground to obtain a battery pack fireproof and heat-insulating coating.

[0041] Example 3

[0042] In this example, the components and weight fractions of the battery pack fireproof and heat-insulating coating are as follows: 55 parts of the composite flame-retardant charring agent, 100 parts of the modified phenolic resin, 18 parts of the filler, which is an equal mass mixture of zinc borate and nano-silicon dioxide, 3 parts of the silane coupling agent KH-550, and 1 part of the defoaming agent polydimethylsiloxane.

[0043] In this example, the preparation method of the battery pack fireproof and heat-insulating coating is as follows:

[0044] S1. 2,6-dimethylphenol, tetramethyl bisphenol A, cuprous bromide, di-n-butylamine and toluene were mixed in a mass ratio of 10:3:0.005:0.006:30, and the temperature was raised to 65°C. Oxygen was passed at a rate of 1.0 ml / min until the end of the reaction. The reaction was stirred at 400 rpm for 3 h. An equimolar amount of trisodium nitrilotriacetate was added to the cuprous bromide. The temperature was raised to 80°C, and the reaction was continued for 50 min. After standing and separating the liquid, methanol was added for precipitation. After filtration, the product was dried at 70°C under vacuum to obtain a double-end hydroxyl polyphenyl ether. A 37% mass fraction formaldehyde solution was placed in a reaction kettle. The pH was adjusted to 9.0 with sodium hydroxide. An amount of phenol equal to 0.8 times the mass of the formaldehyde solution was added. The temperature was raised to 75°C. The reaction was stirred at 400 rpm for 45 min. An amount of melamine equal to 0.4 times the mass of the phenol was added in three portions at 15 min intervals. The reaction was continued for 60 min. The pH was adjusted to 6.0 with hydrochloric acid. The temperature was raised to 90°C. The reaction was continued for 3 h. The temperature was cooled to room temperature. The product was dehydrated under vacuum at 80°C to obtain an amino phenolic resin. Under a nitrogen atmosphere, 1,3-dimercapto-2-propanol and cinnamaldehyde were mixed in equal amounts. An amount of 32% mass fraction hydrochloric acid equal to 0.08 times the mass of the cinnamaldehyde was added dropwise at a rate of 3 ml / min. The reaction was stirred at 400 rpm for 35 min. The product was washed with deionized water 5 times. It was dissolved in tetrahydrofuran and precipitated with n-hexane. The product was purified by gel column chromatography using tetrahydrofuran as the eluent. The product was dried under vacuum at room temperature to obtain a polythioacetal. The double-end hydroxyl polyphenyl ether and toluene were mixed in a mass ratio of 1:1. After stirring uniformly at a temperature of 70°C, an amount of amino phenolic resin equal to 0.5 times the mass of the double-end hydroxyl polyphenyl ether was added. The reaction was continued for 2 h. An amount of polythioacetal equal to 0.4 times the mass of the double-end hydroxyl polyphenyl ether and an amount of catalyst nickel chloride hexahydrate equal to 0.004 times the mass of the double-end hydroxyl polyphenyl ether were added. The temperature was raised to 100°C. The reaction was continued for 4 h. The pH was adjusted to 9 with triethylamine. An amount of crosslinking agent divinylbenzene equal to 0.1 times the mass of the double-end hydroxyl polyphenyl ether was added. The temperature was raised to 140°C. The reaction was continued for 5 h. The product was precipitated with methanol. It was filtered and washed with deionized water and ethanol 5 times, respectively. The product was dried at 70°C under vacuum to obtain a modified phenolic resin.

[0045] S2. Piperazine is mixed with dichloromethane at a mass ratio of 1:25, and placed in an ice bath. Chlorosulfonyl isocyanate is added at a rate of 10 ml / min, with a molar mass of 2.05 times that of piperazine. The reaction is allowed to proceed for 2.5 h, and then quenched with ice water. The mixture is separated, dried with anhydrous magnesium sulfate, and concentrated under reduced pressure. The concentrate is transferred to anhydrous acetonitrile in an amount of 10 times that of piperazine, and placed in a -10℃ environment. Triethylamine is added at a rate of 10 ml / min, in an amount of 3.5 times that of piperazine, followed by chloroacetyl chloride in an amount of 3.2 times that of piperazine. The reaction is allowed to proceed for 4 h, and then filtered and concentrated under pressure. The product is purified by column chromatography, using dichloromethane and methanol at a volume ratio of 20:1 as the eluent, to obtain a sulfonated piperazine compound. Ethanol and deionized water are mixed at a mass ratio of 20:2, and heated to 92℃. After stirring until uniform, 0.05 times the mass of the ethanol is added as molten diamino diphenyl methane, and 0.1 times the mass of the ethanol is added as ammonium polyphosphate. The temperature is lowered to 62℃, and the reaction is allowed to proceed for 4-6 h. The mixture is cooled to room temperature, filtered, and dried, and then ground to obtain diamino diphenyl methane modified ammonium polyphosphate. The diamino diphenyl methane modified ammonium polyphosphate is mixed with anhydrous N-methyl pyrrolidone at a mass ratio of 3:5, and heated to 70℃. After stirring until uniform, the temperature is lowered to 50℃. 0.6 times the mass of the diamino diphenyl methane modified ammonium polyphosphate is added as 4,4'-dimercaptodiphenyl sulfide, and the reaction is allowed to proceed for 2 h. 1.8 times the mass of the diamino diphenyl methane modified ammonium polyphosphate is added as the sulfonated piperazine compound, and 0.02 times the mass of the diamino diphenyl methane modified ammonium polyphosphate is added as the catalyst dibutyltin dilaurate. The temperature is raised to 80℃, and the reaction is allowed to proceed for 4 h. The reaction is quenched with methanol, and then precipitated with deionized water. The precipitate is washed with deionized water and ethanol five times in succession, and dried under vacuum at 70℃, to obtain a composite flame-retardant charring agent.

[0046] S3. The composite flame-retardant charring agent, modified phenolic resin, filler, silane coupling agent, and defoaming agent are mixed and ground, to obtain a battery pack fireproof and heat-insulating coating.

[0047] Comparative Example 1

[0048] The preparation method of Comparative Example 1 is the same as that of Example 2. The battery pack fireproof and heat-insulating coating of Comparative Example 1 differs from that of Example 2 in that the modified phenolic resin is obtained by reacting a double-end hydroxyl polyphenyl ether with an amino phenolic resin.

[0049] Comparative Example 2

[0050] The preparation method of Comparative Example 2 is the same as that of Example 2. The battery pack fireproof and heat-insulating coating of Comparative Example 2 differs from that of Example 2 in that the modified phenolic resin is obtained by reacting an amino phenolic resin with a polythioacetal.

[0051] Comparative Example 3

[0052] The preparation method of Comparative Example 3 is the same as that of Example 2. The battery pack fireproof and heat-insulating coating of Comparative Example 3 differs from that of Example 2 in that the modified phenolic resin is only an amino phenolic resin.

[0053] Comparative Example 4

[0054] The preparation method of Comparative Example 4 is the same as that of Example 2. The battery pack fireproof thermal insulation coating is different from that of Example 2 in that the composite flame-retardant charring agent is prepared by reacting 4,4'-dimercaptodiphenyl sulfide and diamino diphenyl methane modified ammonium polyphosphate.

[0055] Comparative Example 5

[0056] The preparation method of Comparative Example 5 is the same as that of Example 2. The battery pack fireproof thermal insulation coating is different from that of Example 2 in that the composite flame-retardant charring agent is prepared by reacting a sulfonamide compound and diamino diphenyl methane modified ammonium polyphosphate.

[0057] Comparative Example 6

[0058] The preparation method of Comparative Example 6 is the same as that of Example 2. The battery pack fireproof thermal insulation coating is different from that of Example 2 in that the composite flame-retardant charring agent is only diamino diphenyl methane modified ammonium polyphosphate.

[0059] Effect Example

[0060] Table 1 below is the performance test results of the battery pack fireproof thermal insulation coatings prepared in the examples and comparative examples;

[0061] Table 1

[0062] Thermal weight loss rate (%) Limiting oxygen index (LOI) Resistance to stone impact Temperature rise rate (°C / min) Example 1 3 45 No bare spots 62 Example 2 2 48 No bare spots 59 Example 3 2 43 No bare spots 64 Comparative Example 1 10 36 No bare spots 87 Comparative Example 2 8 38 Bare spots 89 Comparative Example 3 12 40 No bare spots 94 Comparative Example 4 11 38 No bare spots 91 Comparative Example 5 14 37 No bare spots 95 Comparative Example 6 19 34 No bare spots 105

[0063] As can be seen from the performance data in Table 1, the battery pack fireproof thermal insulation coating prepared by the present application not only has light quality, but also has excellent mechanical strength, flame retardancy and thermal stability;

[0064] As can be seen from the experimental data of Example 1, Example 2, Example 3 and Comparative Example 1, Comparative Example 2 and Comparative Example 3, the modified phenolic resin prepared by reacting double-end hydroxyl polyphenyl ether, amino phenolic resin and polythioacetal can synergistically flame retard with the composite flame-retardant charring agent due to the introduction of phosphorus, nitrogen and sulfur. The flexible segment introduced by polythioacetal can also buffer thermal stress and improve thermal stability. The modified phenolic resin with double-end hydroxyl polyphenyl ether not only has high temperature resistance and mechanical strength, but also has self-repairing ability through the dynamic crosslinking points introduced by the Schiff base reaction of polythioacetal.

[0065] From the experimental data comparison of Example 1, Example 2, Example 3 and Comparative Example 4, Comparative Example 5, Comparative Example 6, it can be found that the sulfide generated by the reaction of the sulfonamide piperazine compound with the mercapto group, and the polyammonium phosphate introduced by the ion exchange reaction, enhances the compatibility with the resin matrix, and the synergistic effect of multiple elements also provides abundant acid source and gas source, the sulfur oxide generated by the oxidation of the sulfide bond at high temperature combines with the decomposition product of the polyammonium phosphate to form a dense, high-strength expanded carbon layer, effectively blocking the heat radiation and oxygen diffusion, thereby significantly improving the carbonization and thermal stability of the coating.

[0066] Obviously, the above embodiments are only examples for clearly illustrating the embodiments of the present application, and are not intended to limit the embodiments of the present application. Based on the above description, other different forms of changes or variations can be made by those skilled in the art. Here, it is not necessary and also impossible to enumerate all the embodiments. The changes or variations which are obviously extended from the spirit of the present application are still within the protection scope of the present application.

Claims

1. A fireproof thermal barrier coating for a battery pack, characterized by, The raw material components include the following by weight: 45-55 parts of a composite flame-retardant charring agent, 100 parts of a modified phenolic resin, 12-18 parts of a filler, 1-3 parts of a silane coupling agent, and 0.5-1 part of an antifoaming agent; the modified phenolic resin is prepared by reacting a double-end hydroxyl polyphenyl ether, an amino phenolic resin, and a polythioacetal; the composite flame-retardant charring agent is prepared by reacting a sulfonamide piperazine compound, 4,4'-dimercaptodiphenyl sulfide, and diamino diphenyl methane modified ammonium polyphosphate; the modified phenolic resin is prepared by reacting a double-end hydroxyl polyphenyl ether, an amino phenolic resin, and a polythioacetal; the double-end hydroxyl polyphenyl ether is prepared by reacting 2,6-dimethyl phenol and tetramethyl bisphenol A; the polythioacetal is prepared by polymerizing 1,3-dimercapto-2-propanol and cinnamaldehyde; the composite flame-retardant charring agent is prepared by reacting a sulfonamide piperazine compound, 4,4'-dimercaptodiphenyl sulfide, and diamino diphenyl methane modified ammonium polyphosphate; the sulfonamide piperazine compound is prepared by reacting chlorosulfonyl isocyanate with piperazine, and then reacting with chloroacetyl chloride.

2. The fireproof and thermal insulation coating for battery pack according to claim 1, characterized in that, The filler is an equal mass mixture of zinc borate and nano-silicon dioxide; the silane coupling agent is KH-550; and the antifoaming agent is polydimethylsiloxane.

3. The preparation method of the fireproof and thermal insulation coating for battery pack according to claim 1, characterized in that, The method includes the following specific steps: S1. A double-end hydroxyl polyphenyl ether is mixed with toluene at a mass ratio of 1:0.5-1, heated to 60-70 DEG C, stirred until uniform, then 0.3-0.5 times the mass of the double-end hydroxyl polyphenyl ether of an amino phenolic resin is added, and the reaction is continued for 1-2 hours, then 0.2-0.4 times the mass of the double-end hydroxyl polyphenyl ether of a polythioacetal and 0.002-0.004 times the mass of the double-end hydroxyl polyphenyl ether of a catalyst, nickel chloride hexahydrate, are added, heated to 80-100 DEG C, and the reaction is continued for 2-4 hours, then the pH is adjusted to 8-9 with triethylamine, 0.05-0.1 times the mass of the double-end hydroxyl polyphenyl ether of a crosslinking agent, divinyl benzene, is added, heated to 120-140 DEG C, and the reaction is continued for 3-5 hours, then methanol is added to precipitate, the product is filtered and washed with deionized water and ethanol 3-5 times, and vacuum dried at 60-70 DEG C to obtain a modified phenolic resin; S2. Diamino diphenyl methane modified ammonium polyphosphate is mixed with anhydrous N-methyl pyrrolidone at a mass ratio of 2-3:5, heated to 60-70 DEG C, stirred until uniform, then cooled to 40-50 DEG C, 0.5-0.6 times the mass of the diamino diphenyl methane modified ammonium polyphosphate of 4,4'-dimercaptodiphenyl sulfide is added, and the reaction is continued for 1-2 hours, then 1.6-1.8 times the mass of the diamino diphenyl methane modified ammonium polyphosphate of a sulfonamide piperazine compound and 0.01-0.02 times the mass of the diamino diphenyl methane modified ammonium polyphosphate of a catalyst, dibutyl tin dilaurate, are added, heated to 70-80 DEG C, and the reaction is continued for 3-4 hours, then quenched with methanol, precipitated with deionized water, washed with deionized water and ethanol 3-5 times, and vacuum dried at 60-70 DEG C to obtain a composite flame-retardant charring agent; S3. The composite flame-retardant charring agent, the modified phenolic resin, the filler, the silane coupling agent, and the antifoaming agent are mixed and ground to obtain a battery pack fireproof and heat insulation coating.

4. The preparation method of the fireproof and thermal insulation coating for battery pack according to claim 3, characterized in that, In the step S1, the preparation method of the double-end hydroxyl polyphenyl ether is as follows: 2,6-dimethylphenol, tetramethyl bisphenol A, cuprous bromide, di-n-butylamine and toluene are mixed in a mass ratio of 10:0.5-3:0.003-0.005:0.004-0.006:30, heated to 45-65℃, oxygen is passed at a rate of 0.5-1.0 ml / min until the reaction is completed, the reaction is stirred at 200-400 rpm for 2-3 h, equimolar amount of ammonia triacetic acid trisodium of cuprous bromide is added, heated to 70-80℃, and the reaction is continued for 40-50 min, and then the reaction is allowed to stand and separated, and then precipitated with methanol, filtered and vacuum dried at 60-70℃ to obtain the double-end hydroxyl polyphenyl ether.

5. The preparation method of the fireproof and thermal insulation coating for battery pack according to claim 3, characterized in that, In the step S1, the preparation method of the amino phenolic resin is as follows: a formaldehyde solution with a mass fraction of 37% is placed in a reaction kettle, the pH is adjusted to 8.5-9.0 with sodium hydroxide, phenol with a mass of 0.6-0.8 times that of the formaldehyde solution is added, heated to 73-75℃, and the reaction is stirred at 200-400 rpm for 30-45 min, and then the total mass of melamine with a mass of 0.2-0.4 times that of the phenol is added in 2-3 portions with an interval of 15 min, and the reaction is continued for 50-60 min, the pH is adjusted to 4.5-6.0 with hydrochloric acid, heated to 80-90℃, and the reaction is continued for 2-3 h, cooled to room temperature, and vacuum dehydrated at 60-80℃ to obtain the amino phenolic resin.

6. The preparation method of the fireproof and thermal insulation coating for battery pack according to claim 3, characterized in that, In the step S1, the preparation method of the polythioacetal is as follows: 1,3-dimercapto-2-propanol and cinnamaldehyde are mixed in equal mass under nitrogen atmosphere, and the mass fraction of 28-32% hydrochloric acid with a mass of 0.06-0.08 times that of the cinnamaldehyde is added dropwise at a rate of 1-3 ml / min, the reaction is stirred at 200-400 rpm for 25-35 min, washed with deionized water for 3-5 times, dissolved in tetrahydrofuran, precipitated with n-hexane, purified by gel column with tetrahydrofuran as the eluent, and vacuum dried at room temperature to obtain the polythioacetal.

7. The preparation method of the fireproof and thermal insulation coating for battery pack according to claim 3, characterized in that, In the step S2, the preparation method of the sulfonamide piperazine compound is as follows: piperazine and dichloromethane are mixed in a mass ratio of 1:22-25, and placed in an ice bath, and chlorosulfonyl isocyanate with a molar mass of 1.95-2.05 times that of the piperazine is added dropwise at a rate of 8-10 ml / min for 1.5-2.5 h, and then the reaction is quenched with ice water, separated, dried with anhydrous magnesium sulfate, concentrated under reduced pressure, transferred to anhydrous acetonitrile with a mass of 8-10 times that of the piperazine, placed at 0-10℃, and then triethylamine with a mass of 3.4-3.5 times that of the piperazine and chloroacetyl chloride with a mass of 3.1-3.2 times that of the piperazine are added dropwise at a rate of 8-10 ml / min, respectively, and the reaction is continued for 3-4 h, filtered and concentrated under pressure, and then column chromatography is performed with dichloromethane and methanol in a volume ratio of 20:1 as the eluent to obtain the sulfonamide piperazine compound.

8. The method for preparing a fire-retardant and heat-insulating coating for a battery pack according to claim 3, characterized in that, In the step S2, the preparation method of the diamino diphenyl methane modified ammonium polyphosphate is as follows: mixing ethanol and deionized water in a mass ratio of 20:1~2, heating to 90~92℃, stirring uniformly, then adding 0.04~0.05 times of the mass of ethanol of molten diamino diphenyl methane and 0.08~0.1 times of the mass of ethanol of ammonium polyphosphate, cooling to 58~62℃, reacting for 4~6h, cooling to room temperature, filtering, drying, and grinding to obtain the diamino diphenyl methane modified ammonium polyphosphate.