Multi-effect flame retardant, high flash point fire retardant coating and their preparation method

Abstract

The application discloses a multi-effect flame retardant, a high-flash-point fireproof coating and a preparation method thereof, and belongs to the technical field of fireproof coatings. The high-flash-point fireproof coating comprises the following components in mass fractions: 100-120 parts of polyether polyol, 70-90 parts of isocyanate, 10-25 parts of multi-effect flame retardant, 2-5 parts of catalyst, 5-12 parts of defoaming agent and 5-15 parts of flame-retardant auxiliary agent. The multi-effect flame retardant is prepared from hexachlorocyclotriphosphazene and 3-bromo-4-chloroaniline. The multi-effect flame retardant is used to synergistically improve the fireproof effect of the polyurethane fireproof coating by virtue of multiple flame-retardant effects, and the prepared fireproof coating has good flame-retardant effect and high flash point.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of fireproof coating, more particularly, relates to a multi-effect flame retardant, a high-flash-point fireproof coating and a preparation method thereof. BACKGROUND

[0002] Steel structure fireproof coating refers to a kind of functional engineering material coated on the surface of steel, which can play a decorative role in general conditions; when fire occurs, it can prevent flame propagation, isolate the source of fire, increase the heat insulation performance of steel, avoid the destruction of steel structure building and even collapse, and play a time-delaying and protective role for personnel escape, rescue and fire extinguishing. According to different fireproof mechanisms, it can be divided into gas phase flame retardant and condensed phase flame retardant. Among them, the condensed phase flame retardant uses the heat-melting softening of the film-forming material, the reaction of the catalytic dehydration agent and the carbonization agent to generate viscous esterification products, the thermal decomposition of the foaming agent to produce inert gas, and the expansion of the mixture of the molten film-forming material and the viscous esterification products to form a dense fireproof and heat insulation layer, the expansion ratio can reach 10-100 times of the coating thickness, forming a heat insulation barrier between the flame and the steel structure, slowing down the inward heat transfer and improving the fire resistance of the steel structure. However, the condensed phase flame retardant mainly plays a heat insulation role, and the fire suppression effect is poor, and it is still necessary to further improve its flame retardant and fireproof efficiency. Therefore, there is an urgent need for a flame retardant with multi-effect flame retardant effect to enhance the fireproof performance of the fireproof coating.

[0003] According to the search, the patent with the publication number CN103923294A discloses a preparation method of a single-component flame-retardant polyurethane foam sealant, which is prepared by using the following raw materials: flame-retardant polyester polyol, flame-retardant polyether polyol, polyester polyol, polyether polyol, flame retardant, foam stabilizer, catalyst, foaming agent. Although the patent uses flame-retardant elements containing chlorine, bromine, phosphorus and nitrogen, the foaming layer is relatively thick, and it is not suitable for steel structures with small thickness requirements.

[0004] The patent with the publication number CN108976370A discloses a preparation method of a hydrophobic flame-retardant polyurethane elastomer, which includes the following steps: adding pentaerythritol into phosphorus oxychloride, heating and reacting to obtain material a, adding toluene and triethylamine, heating, and dropping dimethyl phosphine oxide to obtain material b; adding hexadecyl trimethyl ammonium bromide into water, adding carbon nanotubes, white carbon black and nano calcium carbonate, ultrasonicating and ball milling to obtain material c; adding material b and 4,4'-diphenyl methane diisocyanate into poly caprolactone diol, stirring and reacting to obtain a polyurethane prepolymer; adding dibutyl tin dilaurate, 1,4-butanediol, polyether polyol 330N, pentaerythritol, hydroxyl fluorine propylene emulsion, material c and dimethyl phthalate into the prepolymer, stirring and reacting, pouring into a mold, drying and curing to obtain the polyurethane elastomer. However, the C content is relatively low, and the ratio of the flame-retardant elements is unreasonable, which is not conducive to the formation of fireproof coating with better flame-retardant performance. SUMMARY

[0005] 1. PROBLEMS TO BE SOLVED

[0006] In order to solve the problem that the fire-retardant elements in the existing fire-retardant agent are not reasonably matched, resulting in poor fire-retardant performance of the fire-retardant coating, the application provides a multi-effect fire-retardant agent and a preparation method thereof.

[0007] Another purpose of the application is to provide a high-flash-point fire-retardant coating containing the above-mentioned fire-retardant agent, and the prepared fire-retardant coating has good fire-retardant performance and high flash point.

[0008] 2. TECHNICAL SCHEME

[0009] In order to solve the above-mentioned problems, the technical scheme adopted by the application is as follows:

[0010] The application discloses a multi-effect fire-retardant agent, and a structural formula of the multi-effect fire-retardant agent is

[0011]

[0012] In the formula, the content of C is 15wt%-25wt%, the content of P is 2wt%-6wt%, the content of N is 4wt%-8wt%, the content of Cl is 15wt%-25wt%, and the content of Br is 40wt%-50wt%.

[0013] The application discloses a preparation method of the above-mentioned multi-effect fire-retardant agent, and the preparation method comprises the following steps:

[0014] Step S1, mixing: mixing hexachlorocyclotriphosphazene and 3-bromo-4-chloroaniline; wherein the mass ratio of hexachlorocyclotriphosphazene to 3-bromo-4-chloroaniline is (20-30):(200-250);

[0015] Step S2, reaction: stirring and reacting the mixture obtained in step S1 in an inert atmosphere; wherein the reaction temperature is 100-120 DEG C, the reaction time is 2-4 hours, and the inert atmosphere is nitrogen, helium or neon, which is used for protecting the amino group from being oxidized and improving the yield of the product;

[0016] Step S3, evaporation: vacuum rotary evaporation of the mixture obtained in step S2, which is used for removing unreacted hexachlorocyclotriphosphazene and 3-bromo-4-chloroaniline and reducing the generation of by-products; the evaporation temperature is 180-200 DEG C, and the evaporation time is 2-4 hours;

[0017] Step S4, washing: washing and filtering three times by using a dilute acid solution with a concentration of 0.1-0.2 mol / L; the dilute acid solution can be dilute hydrochloric acid or dilute nitric acid, which is used for removing residual hexachlorocyclotriphosphazene and 3-bromo-4-chloroaniline.

[0018] Step S5, drying: the product is continuously dried in a 70℃ oven for 24h, finally obtaining a multi-effect flame retardant.

[0019] The above multi-effect flame retardant is added into the fireproof paint to prepare a high flash point fireproof paint, the high flash point fireproof paint comprises the following components in mass fraction: polyether polyol 100-120 parts, isocyanate 70-90 parts, multi-effect flame retardant 10-25 parts, catalyst 2-5 parts, defoaming agent 5-12 parts, and flame retardant aid 5-15 parts.

[0020] According to the provisions of the national standard GB / T13690-92 "Classification and Marking of Common Hazardous Chemicals", the liquid with a flash point lower than 60℃ is a dangerous product, and there is a safety hazard in the process of transportation and storage, which limits the application of the paint thinner as a market commodity. Therefore, the flash point (closed) > 60℃ is referred to as a high flash point, and the polyether polyol is used as a base material in the present application, and the flash point is 230°F, i.e. 110℃, the flash point of the prepared fireproof paint is greater than 60℃, which is a high flash point indoor steel structure fireproof paint.

[0021] The catalyst comprises one or more of dibutyltin dilaurate, stannous octoate and bis(dodecylthio)dibutyltin, which is used to catalyze the reaction of isocyanate and polyether polyol to form the base material of the paint. The isocyanate is selected from one or more of toluene diisocyanate, diphenylmethane-4,4'-diisocyanate or polymethylene polyphenyl polyisocyanate. The polyether polyol is preferably a low molecular weight polyether polyol with di-functionality or tri-functionality, with a molecular weight of 200-5000 and a hydroxyl value of 20-100mgKOH / g.

[0022] The flame retardant aid is a mixture of pentaerythritol, di-pentaerythritol and melamine, with a mass ratio of 5:5:2.

[0023] The defoaming agent is one or more of phosphoric acid ester, amide and silicone. The phosphoric acid ester is selected from one or more of tributyl phosphate, monoalkyl phosphate or dialkyl phosphate, the amide is selected from one or more of monoamide or diamide, and the silicone is selected from one or more of polydimethylsiloxane or silyl ether copolymer.

[0024] The present application uses hexachlorocyclotriphosphazene and 3-bromo-4-chloroaniline as raw materials to generate a highly symmetrical flame retardant, and the reaction formula is as follows Figure 2As shown, the prior art has a C, N, P, Cl, Br synergistic effect, improve the flame retardant performance of phosphorus-containing flame retardant, enhance the flame retardant effect. But on the one hand, the mechanism of the flame retardant can not realize the uniform distribution of elements, such as patent CN108976370A although the integration of C, N, P, Cl, Br element, but the distribution of each element in the molecule is uneven, on the other hand, the C content in the flame retardant is not high, which leads to the flame retardant performance can not be further improved. Therefore, the present application introduces C, P, N, Br, Cl elements in the molecular formula of the flame retardant, to realize the uniform distribution of elements in the flame retardant with high symmetry molecular structure; on the other hand, the C content in the nitrogen and phosphorus flame retardant compound is controlled to be 15wt%-25wt%, the P content is 2wt%-6wt%, the N content is 4wt%-8wt%, the Cl content is 15wt%-25wt%, and the Br content is 40wt%-50wt%, the C content is increased, and the C content is controlled by selecting appropriate flame retardant additives. The C content in the phosphorus-containing chlorine flame retardant of the present application is 15-25%, which is small, so the high carbon content of pentaerythritol, melamine, melamine phosphate is selected as the flame retardant additive, the C content of the fireproof coating is increased, the carbon source is supplemented, and the synthesized multi-effect flame retardant is used, which is beneficial to form a more solid and thicker carbon layer to protect the matrix. In addition, during the test, the flame retardant performance of the coating is adjusted, such as heat release rate, smoke production, when used, the higher C content is beneficial to the formation of carbon layer, P improves the carbonization rate, N produces N-containing gas (NO, NO2, HCN, etc.) during thermal decomposition, which can dilute the oxygen content around the burning object and prevent burning; on the other hand, the generated nitrogen-containing gas realizes the expansion of the carbon layer, and the phosphorus contained in the flame retardant can promote the generation of more carbon, increase the volume of the carbon layer, and improve the thickness of the carbon layer to insulate heat. At the same time, a small amount of Cl is added to play a role in capturing free radicals in the expanded carbon layer and blocking the combustion chain, achieving the synergistic effect of gas phase flame retardation and condensed phase flame retardation. But there is still the problem of low gas phase flame retardation efficiency. Therefore, the present application introduces Br, which uses the free radical flame retardation mechanism to improve the flame retardation effect, and controls the proportion of Br. If the proportion of Br is too high, the solid phase flame retardation efficiency will be affected, and if the proportion of Br is too low, the flame retardation efficiency will be affected. In this process, too high or too low of some components in C, N, P, Cl will lead to insufficient density or thickness of the carbon layer.

[0025] Compared with the C, N, P, Cl, Br-containing flame retardant in the prior art, the C content in the flame retardant is controlled to be 15wt%-25wt%, but the N and P improve the carbonization effect, so the N and P content is high, the N and P and C synergistic effect is used to improve the carbonization effect, and the halogens Cl and Br are introduced to form a flame retardant with better flame retardation effect.

[0026] The application also discloses a method for preparing the high-flash-point fireproof paint.

[0027] Step a, adding the multi-effect fire retardant into the polyether polyol and treating with an ultrasonic instrument for 20-40 min.

[0028] Step b, slowly adding a catalyst, a fire retardant aid, an antifoaming agent and isocyanate and continuously stirring for 3-6 min.

[0029] Step c, coating the prepared sample on a mild steel plate with a knife blade film coater, the coating thickness is 195-205 mu m, curing the sample in an oven at 40-60 DEG C for 2-4 h at room temperature overnight to obtain the high-flash-point fireproof paint.

[0030] 3. Beneficial effects

[0031] Compared with the prior art, the application has the beneficial effects that:

[0032] (1) The application controls the C content of the fire retardant compound to be 15wt%-25wt%, the P content to be 2wt%-6wt%, the N content to be 4wt%-8wt%, the Cl content to be 15wt%-25wt% and the Br content to be 40wt%-50wt%, improves the C content, and meanwhile, by selecting a suitable fire retardant aid, the C content is regulated, which is beneficial to forming a carbon layer with better heat insulation performance and improving the fire retardant performance.

[0033] (2) The application has a high degree of symmetry in the molecular formula of the fire retardant compound, the C, P, N, Cl and Br elements are uniformly distributed in the fire retardant, the elements synergistically act to improve the fire retardant performance. BRIEF DESCRIPTION OF DRAWINGS

[0034] The technical solutions of the application will be further described in detail below in combination with the drawings and examples, but it should be known that the drawings are only designed for the purpose of explanation, thus not as the limitation of the scope of the application. In addition, unless specifically indicated, the drawings are only intended to conceptually illustrate the structural configuration described herein, and are not necessarily drawn in proportion.

[0035] Figure 1 is the structural formula of the multi-effect fire retardant of the application;

[0036] Figure 2 is the preparation reaction formula of the multi-effect fire retardant of the application;

[0037] Figure 3 is the infrared spectrum of the multi-effect fire retardant prepared in Example 1. DETAILED DESCRIPTION

[0038] The following detailed description of example embodiments of the application references the drawings, which form a part thereof, and in which are shown by way of illustration, example embodiments in which the application can be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the application, and it is to be understood that other embodiments can be utilized and that changes can be made without departing from the spirit and scope of the present application. The following detailed description is, therefore, not to be taken in a limiting sense, as the scope of the application is defined by the appended claims.

[0039] The polyether polyols of Examples 1-3 were purchased from Guangzhou Hengyu Chemical Co., Ltd. 230 series polyether polyols.

[0040] Example 1

[0041] A high flash point fire-retardant coating, comprising the following components in mass fraction: polyether polyol 100 parts, isocyanate 70 parts, multi-effect flame retardant 10 parts, catalyst 2 parts, defoaming agent 5 parts, flame retardant aid 5 parts.

[0042] The isocyanate is toluene diisocyanate, and the defoaming agent is monoamide.

[0043] The flame retardant aid is a mixture of pentaerythritol, di-pentaerythritol and melamine, and the mass ratio is 5:5:2.

[0044] The catalyst is a mixture of dibutyl tin diacetate, stannous octoate and di(dodecylthio) dibutyl tin, and the mass ratio is 1:2:2.

[0045] The preparation process of the multi-effect flame retardant comprises the following steps:

[0046] Step S1, mixing: 20 g of hexachlorocyclotriphosphazene is mixed with 200 g of 3-bromo-4-chloroaniline;

[0047] Step S2, reaction: the mixture is stirred at 100°C under nitrogen atmosphere for 2 h;

[0048] Step S3, evaporation: vacuum rotary evaporation at 180°C for 2 h;

[0049] Step S4, washing: washing with 0.1 mol / L hydrochloric acid and filtering 3 times;

[0050] Step S5, drying: the product is continuously dried in an oven at 70°C for 24 h, and finally the multi-effect flame retardant is obtained.

[0051] The infrared spectrum of the prepared multi-effect flame retardant is as follows:Figure 3 CH3 2860 cm -1 -NH- 1610 cm -1 Br-C 530 cm -1 Cl-C 625 cm -1 .

[0052] The preparation process of the high flash point fire-retardant coating comprises the following steps:

[0053] Step a, adding a multi-effect flame retardant into a polyether polyol, and ultrasonically treating for 20 min by using an ultrasonic instrument;

[0054] Step b, slowly adding a catalyst, a flame-retardant aid, an antifoaming agent and isocyanate, and continuously stirring for 3 min;

[0055] Step c, coating the prepared sample on a mild steel plate by using a knife blade film coater, the coating thickness is 195 μm, the sample is left overnight at room temperature, and is cured in a 40℃ oven for 2 hours, thereby obtaining the high flash point fire-retardant coating.

[0056] Example 2

[0057] A high flash point fire-retardant coating comprises the following components in mass fraction: polyether polyol 110 parts, isocyanate 80 parts, multi-effect flame retardant 20 parts, catalyst 3 parts, antifoaming agent 10 parts, and flame-retardant aid 10 parts.

[0058] The isocyanate is phenylmethane-4,4'-diisocyanate, and the antifoaming agent is tributyl phosphate.

[0059] The flame-retardant aid is a mixture of pentaerythritol, di-pentaerythritol and melamine, and the mass ratio is 5:5:2.

[0060] The catalyst is a mixture of dibutyl tin diacetate, stannous octoate and di(dodecylthio) dibutyl tin, and the mass ratio is 1:2:2.

[0061] The preparation process of the multi-effect flame retardant comprises the following steps:

[0062] Step S1, mixing: mixing 25 g of hexachlorotriphosphazene with 220 g of 3-bromo-4-chloroaniline;

[0063] Step S2, reaction: stirring the mixture at 110℃ under nitrogen atmosphere for 3 h;

[0064] Step S3, evaporation: vacuum rotary evaporation at 190℃ for 3 h;

[0065] Step S4, washing: washing and filtering 3 times by using 0.15 mol / L hydrochloric acid;

[0066] Step S5, drying: continuously drying the product in an oven at 70℃ for 24h, finally obtaining the multi-effect flame retardant.

[0067] The preparation process of the high-flash-point fire-retardant coating comprises the following steps:

[0068] Step a, adding the multi-effect flame retardant into the polyether polyol, and ultrasonic treatment for 30min by using an ultrasonic instrument;

[0069] Step b, slowly adding the catalyst, flame-retardant aid, amide and isocyanate, continuously stirring for 5min;

[0070] Step c, coating the prepared sample on a mild steel plate by using a blade film coater, the coating thickness is 200μm, the sample is left at room temperature overnight, and is cured in an oven at 50℃ for 3h, thus obtaining the high-flash-point fire-retardant coating.

[0071] Example 3

[0072] A high-flash-point fire-retardant coating comprises the following components in mass fraction: polyether polyol 120 parts, isocyanate 90 parts, multi-effect flame retardant 25 parts, catalyst 5 parts, defoaming agent 12 parts, flame-retardant aid 15 parts.

[0073] The isocyanate is a multi-methylene multi-phenyl polyisocyanate, and the defoaming agent is a polydimethylsiloxane.

[0074] The flame-retardant aid is a mixture of pentaerythritol, di-pentaerythritol and melamine, and the mass ratio is 5:5:2.

[0075] The catalyst is a mixture of dibutyl tin diacetate, stannous octoate and di(dodecylthio) dibutyl tin, and the mass ratio is 1:2:2.

[0076] The preparation process of the multi-effect flame retardant comprises the following steps:

[0077] Step S1, mixing: mixing 30g of hexachlorocyclotriphosphazene with 250g of 3-bromo-4-chloroaniline;

[0078] Step S2, reaction: stirring the mixture at 120℃ under nitrogen atmosphere for 4h;

[0079] Step S3, evaporation: vacuum rotary evaporation at 200℃ for 4h;

[0080] Step S4, washing: washing and filtering 3 times by using 0.2mol / L hydrochloric acid;

[0081] Step S5, drying: continuously drying the product in an oven at 70℃ for 24h, finally obtaining the multi-effect flame retardant.

[0082] The preparation process of the high-flash-point fire-retardant coating comprises the following steps:

[0083] Step a, adding the multi-effect flame retardant into the polyether polyol, and treating with an ultrasonic instrument for 40 min;

[0084] Step b, slowly adding the catalyst, the flame retardant aid, the defoaming agent and the isocyanate, and continuously stirring for 6 min;

[0085] Step c, coating the prepared sample on a mild steel plate with a doctor blade, the coating thickness is 205 μm, curing the sample in an oven at 60℃ for 4 hours, and preparing the high flash point fireproof coating.

[0086] Comparative Example

[0087] A fireproof coating, comprising the following components in mass fraction: polyether polyol 120 parts, isocyanate 90 parts, catalyst 5 parts, defoaming agent 12 parts, and flame retardant aid 15 parts.

[0088] The isocyanate is a multi-methylene multi-phenyl polyisocyanate, and the defoaming agent is a silyl ether copolymer.

[0089] The flame retardant aid is a mixture of pentaerythritol, di-pentaerythritol and melamine, and the mass ratio is 5:5:2.

[0090] The catalyst is a mixture of stannous octoate and di(dodecylthio) dibutyl tin, and the mass ratio is 1:1.

[0091] The preparation process of the fireproof coating comprises the following steps:

[0092] Step a, adding the flame retardant aid into the polyether polyol, and treating with an ultrasonic instrument for 40 min;

[0093] Step b, slowly adding the catalyst, the defoaming agent and the isocyanate, and continuously stirring for 6 min;

[0094] Step c, coating the prepared sample on a mild steel plate with a doctor blade, the coating thickness is 200 μm, curing the sample in an oven at 60℃ for 4 hours, and preparing the fireproof coating.

[0095] The parameters of the fireproof coating prepared in Examples 1-3 are compared with the requirements of the national standards and industry standards for the parameters of the fireproof coating, wherein the maximum heat release rate: ASTM D7309-2007a decomposition residue ratio, decomposition peak temperature: GBT27761-2011, flash point: GB / T 261-2008 determination of flash point by Pensky-Martin closed cup method, and the test results are shown in Table 1:

[0096] Table 1 Test results of the parameters of the fireproof coating of the comparative example and experimental examples 1-3

[0097]

[0098] From Table 1, the detection data of the decomposition residue ratio and the decomposition peak temperature of the coating prepared in Examples 1-3 are all greater than those of the comparative examples, and the maximum heat release rate of the coating prepared in Examples 1-3 is less than that of the comparative examples. It can be known that the fireproof coating prepared in the present application has excellent fireproof performance. The flash point of the fireproof coating of Examples 1-3 is all > 60℃, which meets the requirements of non-dangerous chemical identification in the Safety Regulations for Dangerous Chemicals, and belongs to non-dangerous chemicals, which is beneficial to the storage and transportation of the fireproof coating.

[0099] The above description is only the preferred embodiments of the present application, and is not used to limit the present application. For those skilled in the art, the present application can have various changes, improvements or equivalent replacements of some technical features. Any changes, improvements or equivalent replacements made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A high flash point fire retardant coating characterized in that, The polyether polyol 100-120 parts, isocyanate 70-90 parts, multi-effect flame retardant 10-25 parts, catalyst 2-5 parts, defoaming agent 5-12 parts, flame retardant aid 5-15 parts, the structural formula of the multi-effect flame retardant is ； The coating thickness of the fireproof coating is 195-205 μm, and the flash point is >60℃. The preparation method of the multi-effect flame retardant comprises the following steps: Step S1, mixing: mixing hexachlorocyclotriphosphazene and 3-bromo-4-chloroaniline; Step S2, reaction: stirring and reacting the mixture obtained in step S1 in an inert atmosphere, the reaction temperature is 100-120℃, and the reaction time is 2-4h; Step S3, evaporation: vacuum rotary evaporation of the mixture obtained in step S2, the evaporation temperature is 180-200℃, and the evaporation time is 2-4h; Step S4, washing: washing and filtering with a dilute acid solution; Step S5, drying: drying, and finally obtaining the multi-effect flame retardant.

2. The high flash point fire resistant coating of claim 1, wherein, In the multi-effect flame retardant, the content of C is 15 wt%-25 wt%, the content of P is 2 wt%-6 wt%, the content of N is 4 wt%-8 wt%, the content of Cl is 15 wt%-25 wt%, and the content of Br is 40 wt%-50 wt%.

3. The high flash point fire resistant coating of claim 1, wherein, In step S1, the mass ratio of the hexachlorocyclotriphosphazene to the 3-bromo-4-chloroaniline is (20-30):(200-250); in step S2, the inert atmosphere is nitrogen, helium or neon; in step S4, the dilute acid solution is dilute hydrochloric acid or dilute nitric acid with a concentration of 0.1-0.2 mol / L; and in step S5, the drying temperature is 70℃, and the drying time is 24h.

4. The high flash point fire resistant coating of claim 1, wherein, The flame retardant aid is a mixture of pentaerythritol, di-pentaerythritol and melamine with a mass ratio of 5:5:

2.

5. The high flash point fire resistant coating of claim 1, wherein, The catalyst is one or more of dibutyltin dilaurate, stannous octoate and bis(dodecylthio)dibutyltin, and the defoaming agent is one or more of phosphate ester, amide and silicone.

6. The high flash point fire resistant coating of claim 1, wherein, The isocyanate is selected from one or more of toluene diisocyanate, diphenylmethane-4,4'-diisocyanate or polymethylene polyphenyl polyisocyanate.

7. A process for the preparation of the high flash point fire retardant coating according to any one of claims 1 to 6, characterized in that, The method comprises the following steps: Step a, adding the multi-effect flame retardant into the polyether polyol and mixing uniformly; Step b, slowly adding the catalyst, flame retardant aid, defoaming agent and isocyanate and stirring uniformly; Step c, coating the prepared sample on a mild steel plate, the coating thickness is 195-205 μm, the sample is cured at room temperature overnight to prepare the high-flash-point fireproof coating.

8. The method for preparing a high flash point fire-retardant coating according to claim 7, characterized in that, In step a, ultrasonic treatment is performed for 20-40 min; in step b, the stirring time is 3-6 min; and in step c, the thickness of the coating is 195-205 μm, and the curing is performed at 40-60℃ for 2-4h.

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