CN117126585A - High-heat-flow-resistant expansion type fireproof coating and preparation method thereof - Google Patents

Abstract

The invention belongs to the technical field of coating preparation and relates to a high heat flow-resistant expansion fireproof coating and a preparation method thereof. The high heat flow expansion-resistant fire retardant coating is composed of a top coating and a primer. The components of the top coating include: 50 to 80 parts by mass of epoxy resin and 20 to 40 parts of epoxy resin modifier. , 10 to 25 parts of flame retardant, 25 to 45 parts of carbon-forming agent, 20 to 40 parts of foaming agent, 10 to 30 parts of refractory fiber, 10 to 40 parts of inorganic filler, 5 to 15 parts of curing agent, 5 defoaming agents ~10 parts and organic solvent; the components of the primer coating include: 70~90 parts of phosphate base material in terms of parts by mass. The intumescent fireproof coating prepared by the invention is green and non-toxic, can be cured at room temperature, the viscosity of the coating can be adjusted, and the construction method can be sprayed or brushed. The required coating thickness is thin and the bonding strength with the substrate is high, and it can be used in high heat flow applications. It can improve excellent and stable flame retardant effect under working conditions.

Description

A kind of high heat flow expansion type fire retardant coating and preparation method thereof

Technical field

The invention belongs to the technical field of coating preparation, and more specifically relates to a high heat flow expansion resistant fire retardant coating and a preparation method thereof.

Background technique

Fire retardant coating is a material that can improve the fire resistance of buildings. Its function is to form a fire retardant film on the surface of the building, thereby achieving a fire prevention effect. At present, fire retardant coatings have been widely used in construction, transportation, electronic equipment, chemical equipment and other fields.

According to different fire protection principles, fire retardant coatings can be divided into two categories: non-intumescent coatings and intumescent coatings. The principle of fire protection and heat insulation of non-expandive fire retardant coating is to take advantage of the low thermal conductivity of the coating, which delays the speed of heat transfer to the protected substrate. At the same time, the coating acts as a barrier and prevents thermal radiation to the steel components, avoiding flames and high temperatures. Directly attack steel components, but in order to achieve a certain fire protection and heat insulation effect, the non-expandive fire protection coating needs to be thicker to achieve certain fire protection and heat insulation performance requirements.

Intumescent fire-retardant coatings have the characteristics of rapidly expanding under high temperature conditions and forming a thick thermal insulation layer. The loose foam layer isolates oxygen and delays heat transfer, which can effectively protect the surface of the coated object from damage by high-temperature thermal radiation and flames. Compared with traditional fire retardant coatings, intumescent fire retardant coatings can not only improve the fire protection level and fire protection time, but also increase the thermal insulation performance of the coating and prevent the transfer of heat, thus ensuring the safety of buildings and other facilities.

With the continuous advancement of technology and the expansion of application scenarios, researchers have focused on studying the materials, processes and applications of intumescent fire-retardant coatings. Intumescent fire-retardant coatings are being widely used and developed. However, there are certain problems with the performance stability of some intumescent fire-retardant coatings at present. They are easily affected by environmental factors such as humidity and temperature, reducing their service life and effectiveness. In addition, the coating material components include halogen elements, which are Toxic gases will be produced during use, which does not meet the needs of green environmental protection. In addition, because intumescent fire-retardant coatings have high technical content and complex production processes, production and research and development costs are relatively high, which limits their promotion and use in large-scale applications.

Therefore, how to provide a high heat flow resistant expansion type fire retardant coating and its preparation method, which can solve the problems in the existing technology of complex production and construction of intumescent fire retardant coatings and poor fire protection effect under high heat flow conditions, while being green, environmentally friendly and economical , convenient and safe construction, excellent fire prevention and flame retardant effects, etc. are issues that technicians in this field urgently need to solve.

Contents of the invention

In order to solve the above technical problems, the present invention provides a high heat flow expansion-resistant fire retardant coating and a preparation method thereof. The high heat flow expansion-resistant fire retardant coating prepared by the invention is green and environmentally friendly, and the preparation method is simple. In addition, when constructing fire-retardant coatings, a primer combined with a topcoat is used, which can be cured at room temperature, and the viscosity of the coating can be adjusted. The construction method can be brushing or spraying. The required coating thickness is thin and adheres to the substrate. The knot strength is high, which can improve the excellent and stable flame retardant effect under high heat flow conditions.

In order to achieve the above objects, the present invention provides the following technical solutions:

One of the technical solutions of the present invention is to provide a high heat flow-resistant expansion type fire retardant coating, including a primer coating and a top coating coating;

In terms of parts by mass: the components of the topcoat include 50 to 80 parts of epoxy resin, 20 to 40 parts of epoxy resin modifier, 10 to 25 parts of flame retardant, 25 to 45 parts of carbon-forming agent, and hair growth agent. 20 to 40 parts of foaming agent, 10 to 30 parts of refractory fiber, 10 to 40 parts of inorganic filler, 5 to 15 parts of curing agent, 5 to 10 parts of defoaming agent and 30 to 50 parts of organic solvent; the composition of the primer coating Parts include 70 to 90 parts of phosphate base.

Further, the epoxy resin is F51 type unmodified epoxy resin.

Further, the epoxy resin modifier is polymethylphenylsiloxane (organic silicone modifier).

The large amount of methyl groups in the epoxy resin modifier used in the present invention reduces the compatibility between silicone and epoxy resin, and improves the heat resistance and mechanical properties of the modified resin. The silicone reactive group is used to react with the epoxy resin, and the silicone resin is introduced while retaining the epoxy group. The presence of an appropriate amount of phenyl groups further improves the compatibility between the silicone and the epoxy resin.

The epoxy resin selected in the present invention has high epoxy group content and high viscosity. The cured product has high cross-linking density and good heat resistance. After chemical modification with silicone, the cross-linking density of the system increases and the silicon-oxygen bond replaces part of the Carbon-oxygen bond, because the bond energy of silicon-oxygen bond is higher than that of carbon-oxygen bond, and the electronegativity difference of Si-O atoms is large, and the polarity of Si-O bond is large, it acts as a shield for the connected group function, thereby greatly improving the toughness and heat resistance of the modified epoxy resin.

Further, the flame retardant includes at least one of ammonium polyphosphate, phosphoric acid and ammonium dihydrogen phosphate.

Further, the carbon-forming agent includes one of dipentaerythritol, ethylene glycol and pentaerythritol.

In the present invention, the flame retardant and the carbon-forming agent have a synergistic effect. Through the dehydration effect of the flame retardant, the dehydration of the carbon-forming agent can be accelerated after being heated to form a char layer during the combustion process.

Further, the foaming agent includes at least one of melamine, melamine phosphate and urea.

The foaming agent selected in this invention is a halogen-free foaming agent. When it is thermally decomposed, it will produce a large amount of amine gas or nitrogen, and will not produce toxic gases. On the one hand, it promotes the expanded carbon layer to form a loose foam-like structure, and on the other hand, it reduces The thermal conductivity of the expanded carbon layer improves the flame retardant effect.

Further, the refractory fibers are chopped fibers forming a size gradient gradation, including at least one of chopped high silica fibers, chopped alumina fibers and chopped mullite fibers.

Preferably, the size gradient gradation is composed of refractory fibers with lengths of 6mm, 8mm, 10mm and 12mm, and the mass ratio is 2:2:3:3.

The refractory fibers added in the present invention can synergistically enhance the stability of the expanded carbon layer and simultaneously reduce the heat transfer rate, and the gradient gradation of fiber size can ensure better stability of the expanded carbon layer after the coating encounters fire.

Further, the inorganic filler includes at least one of talc, perlite, expanded graphite, aluminum hydroxide, zirconium boride, hafnium carbide and sepiolite.

In the present invention, the inorganic filler acts as a flame retardant synergist and can synergistically provide excellent fire protection and high temperature resistance for the coating.

Further, the curing agent includes one of polyamide, alicyclic amine and fatty amine.

Furthermore, the defoaming agent is organic silicon defoaming agent BYK-065.

Further, the organic solvent is at least one of anhydrous ethanol, acetone and neopentyl glycol glycidyl ether.

The addition of organic solvent in the present invention can improve the solubility of epoxy resin and epoxy resin modifier, and adjust the viscosity of the coating.

Further, the phosphate base material is composed of aluminum dihydrogen phosphate, zinc oxide, cerium oxide and water, with a mass ratio of 3:1:1:1.

The phosphate base material is used as a bonding material for primer construction, which can ensure the outstanding bonding performance of the paint and provide fire protection properties. Zinc oxide and cerium oxide can also absorb moisture generated during chemical reactions to prevent the overflow of generated water. , slow-release the acidity of the matrix, and at the same time reduce the curing temperature to facilitate large-scale construction at room temperature.

The second technical solution of the present invention is to provide a method for preparing the above-mentioned high heat flow expansion-resistant fire retardant coating, which includes:

Heat and melt the epoxy resin and then raise the temperature to 70-100°C, then add 1/3 of the total amount of epoxy resin modifier and organic solvent to perform a modification reaction to obtain a modified epoxy resin;

Heat the flame retardant and carbon-forming agent to react, add the foaming agent to continue the reaction, and obtain a white solid after grinding and sieving;

Add refractory fiber, inorganic filler and remaining organic solvent to the modified epoxy resin, heat and stir evenly, and obtain a mixed material after ball milling;

After mixing the mixed material with the white solid, a curing agent and a defoaming agent are added and dispersed by ball milling to obtain the top coating;

Aluminum dihydrogen phosphate, zinc oxide and cerium oxide in the phosphate base material are dispersed by ball milling and then sieved to obtain solid powder;

Under the conditions of heating and stirring in a water bath, the solid powder and water are mixed, and the reaction is stirred until the mixture becomes gel-like, thereby obtaining a primer coating.

Further, the modification reaction time is 0.5 to 1 h.

Further, the temperature of the heating reaction is 120-170°C.

Further, the grinding and sieving is passing through a 100-300 mesh sieve.

Further, the temperature of the heating and stirring is 60 to 90°C.

Further, the ball milling is performed at 300 to 600 r/min for 1 to 3 hours.

Further, the sieving after dispersion is 100-300 mesh sieve.

The third technical solution of the present invention is to provide an application of the above-mentioned high heat flow expansion-resistant fire retardant coating in the fields of building steel structure fire protection and new energy battery fire protection.

The fourth technical solution of the present invention is to provide a fire-retardant coating, which is coated with the above-mentioned high heat flow-resistant expansion-type fire-retardant coating.

Further, the coating is to apply the base coating first and then the top coating.

Preferably, the coating thickness of the primer is 900-1000 μm.

Preferably, the coating thickness of the topcoat is 500-800 μm.

It can be seen from the above technical solution that compared with the existing technology, it has the following beneficial effects:

1. In the present invention, the C-O bonds in the silicone-modified resin structure are replaced by Si-O bonds, which improves the cross-linking density of the system. During the heating process, the Si-O bonds have greater bond energy and polarity. It can shield the surrounding groups, prolong the thermal blocking effect when the material is heated, and reduce the heat transfer inside the material.

2. The flame retardant in the raw materials used in the present invention will thermally degrade before the epoxy resin when exposed to heat. During the thermal degradation process, it will absorb a large amount of heat. At the same time, the gas source component in the intumescent flame retardant will produce non-combustible gas and dilute it. The oxygen concentration in the combustion reaction, while the flame retardant and carbon-forming agent are rapidly dehydrated into charcoal at this time, ultimately forming a protective charcoal layer that can isolate the flame and block heat transfer, thereby achieving the purpose of flame retardancy.

3. The refractory fibers and inorganic fillers added to the coating of the present invention provide mechanical support for the protective carbon layer, reducing the heat transfer rate between the coating and the protected object. The size of the refractory fibers presents a gradient gradation, which can ensure a greater degree of protection. The stability of the expanded carbon layer enables the coating to work normally under high heat flow conditions.

4. The high heat flow expansion-resistant fire retardant coating prepared by the present invention can achieve excellent heat insulation and fire retardant effects when the coating thickness is 1400-1800 μm.

5. The intumescent fire-retardant coating prepared by the present invention is green and non-toxic, can be cured at room temperature, the viscosity of the coating can be adjusted, and the construction method can be sprayed or brushed.

Description of the drawings

The drawings that form a part of this application are used to provide a further understanding of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an improper limitation of this application. In the attached picture:

Figure 1 is a test piece coated with the fire retardant coating of Examples 1-3.

Figure 2 shows the combustion back temperature test device in the test example.

Figure 3 is a picture of the expanded carbon layer of the test piece in Example 3 after the combustion back temperature test.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present invention.

The refractory fibers in the present invention are chopped fibers forming a size gradient gradation. The size gradient gradation is composed of refractory fibers with lengths of 6 mm, 8 mm, 10 mm and 12 mm, and the mass ratio is 2:2:3:3.

Example 1

High heat flow expansion resistant fire retardant coating includes the following components in terms of parts by mass:

Top coating: 70 parts of epoxy resin, 30 parts of epoxy resin modifier, 20 parts of flame retardant, 20 parts of carbon-forming agent, 25 parts of foaming agent, 20 parts of refractory fiber, 25 parts of inorganic filler, 10 parts of curing agent 5 parts of defoaming agent and 40 parts of organic solvent.

Primer coating: 80 parts of phosphate base.

Among them, the epoxy resin is F51 unmodified epoxy resin, the epoxy resin modifier is polymethylphenylsiloxane, the flame retardant is phosphoric acid, the carbon-forming agent is dipentaerythritol, and the foaming agent is melamine. The refractory fiber is chopped high silica fiber, the inorganic filler is a mixture of aluminum hydroxide powder and zirconium boride powder with a mass ratio of 1:1, the curing agent is polyamide, the defoaming agent is BYK-065, and the organic solvent is anhydrous Ethanol; the phosphate base material is composed of aluminum dihydrogen phosphate, zinc oxide, cerium oxide and deionized water, with a mass ratio of 3:1:1:1.

Preparation method of high heat flow expansion-resistant fire retardant coating:

S1. Preparation of primer paint

Mix the phosphate base material in proportion, use absolute ethanol as the medium, ball mill at 300r/min for 1 hour to fully disperse, dry and pass through a 200 mesh sieve after dispersion, heat and stir in a water bath at 90°C, grind, disperse and sieve Add deionized water to the final powder, stir and react until it becomes gel-like, and the primer is obtained.

S2. Preparation of topcoat paint

1) Heat and melt the epoxy resin, raise the temperature to 80°C, add epoxy resin modifier and 1/3 of the total amount of organic solvent, react for 1 hour, and cool to room temperature to obtain the modified epoxy resin, which is ready for use.

2) Stir the flame retardant and carbon-forming agent evenly and heat to 120°C. React at 120°C for 4 hours to obtain a colorless transparent liquid. Then add the foaming agent to the transparent liquid and continue the reaction for 4 hours. Finally, the reaction is completed. After grinding, pass through a 200-mesh sieve to obtain a white solid, which is set aside.

3) Mix the modified epoxy resin with refractory fiber, inorganic filler, and remaining organic solvent, raise the temperature to 80°C, stir evenly, and ball-mill at 300 r/min for 1.5 hours to obtain a mixed material for later use.

4) Mix the white solid with the mixed materials, add curing agent and defoaming agent, stir and disperse evenly to obtain the top coating.

Example 2

High heat flow expansion resistant fire retardant coating includes the following components in terms of parts by mass:

Top coating: 70 parts of epoxy resin, 30 parts of epoxy resin modifier, 30 parts of flame retardant, 15 parts of carbon-forming agent, 15 parts of foaming agent, 20 parts of refractory fiber, 30 parts of inorganic filler, 10 parts of curing agent 5 parts of defoaming agent and 40 parts of organic solvent.

Primer coating: 80 parts of phosphate base.

Among them, the epoxy resin is F51 unmodified epoxy resin, the epoxy resin modifier is polymethylphenylsiloxane, the flame retardant is ammonium polyphosphate, the carbon forming agent is dipentaerythritol, and the foaming agent is Urea, the refractory fiber is chopped high silica fiber, the inorganic filler is sepiolite powder, the curing agent is polyamide, the defoaming agent is BYK-065, the organic solvent is absolute ethanol; the phosphate base material is aluminum dihydrogen phosphate , zinc oxide, cerium oxide and deionized water, with a mass ratio of 3:1:1:1.

Preparation method of high heat flow expansion-resistant fire retardant coating:

Compared with Example 1, the difference lies in that the heating temperature in step 2) during the preparation of the topcoat coating is 150°C, and the mixture is ground through a 300-mesh sieve, and the rest is the same as in Example 1.

Example 3

High heat flow expansion resistant fire retardant coating includes the following components in terms of parts by mass:

Top coating: 70 parts of epoxy resin, 30 parts of epoxy resin modifier, 30 parts of flame retardant, 15 parts of carbon-forming agent, 20 parts of foaming agent, 25 parts of refractory fiber, 30 parts of inorganic filler, 10 parts of curing agent 5 parts of defoaming agent and 40 parts of organic solvent.

Primer coating: 70 parts of phosphate base.

Among them, the epoxy resin is F51 unmodified epoxy resin, the epoxy resin modifier is polymethylphenylsiloxane, the flame retardant is phosphoric acid, the carbon-forming agent is pentaerythritol, the foaming agent is melamine, and the fire resistance The fiber is chopped mullite fiber, the inorganic filler is a mixture of sepiolite powder and aluminum hydroxide powder with a mass ratio of 1:1, the curing agent is polyamide, the defoaming agent is BYK-065, and the organic solvent is absolute ethanol. ; The phosphate base material is composed of aluminum dihydrogen phosphate, zinc oxide, cerium oxide and deionized water, with a mass ratio of 3:1:1:1.

The preparation method of the high heat flow expansion-resistant fire retardant coating is the same as in Example 1.

Comparative example 1

Compared with Example 3, the only difference lies in the white solid product prepared by using expanded graphite instead of the flame retardant, carbon-forming agent and foaming agent.

Test example

The primer paints prepared in Examples 1 to 3 and Comparative Example 1 were evenly coated on a 150mm×70mm standard test steel plate with a coating thickness of 900 μm, and dried at room temperature for 8 hours. After drying, the topcoat paint was evenly applied. Coating on the surface of the primer coating, the coating thickness is 500 μm. After 72 hours, the coating is completely cured at room temperature, and a test piece coated with a fire retardant coating is obtained. As shown in Figure 1, from left to right are coating example 1 and implementation. Test pieces of Example 2 and Example 3 coatings.

In order to examine the thermal insulation performance of the material in practical applications, the device shown in Figure 2 was used for testing.

1. Combustion back temperature test

Test Methods:

The test pieces prepared in Examples 1 to 3 and Comparative Example 1 were fixed on the test bench respectively using brackets, and then a thermocouple for measuring temperature was fixed on the back of the test piece, and a methane spray gun was used to burn the front of the sample. The burning temperature is 1200°C and lasts for 10 minutes. Record the temperature of the backside when burning for 5 minutes and 10 minutes, and record them as T ₁ and T ₂ . The combustion back temperature test data is shown in Table 1:

Table 1

It can be seen from the data in Table 1 that after continuous burning with a 1200°C flame for 10 minutes, the back surface temperature of the samples in Examples 1 to 3 did not exceed 500°C, showing a relatively obvious heat insulation effect and being able to burn under actual flame conditions. This ensures that the back material is not damaged by high temperatures.

By comparing the T ₁ and T ₂ data of Example 3 and Comparative Example 1, it can be seen that the back temperature after burning for 5 minutes in Example 3 dropped by 44.8%, and the back temperature after burning for 10 minutes dropped by 38.9%. , it can be seen that the fire retardant coating prepared by this application has excellent heat insulation performance.

2. Thermal stability performance test

Test method: Thermogravimetric-differential thermal (TG-DSC) analysis is used to conduct thermal analysis at a rate of 10°C/min. The temperature is raised to 1200°C to test the cured coating material and analyze its thermal response.

Record the heating temperature when the sample loses 10% and 50% weight and the residual weight rate of the sample at 600°C and 1200°C. The results are shown in Table 2.

Table 2

Judging from the numerical values of the residual weight ratio of the data in Table 2, the residual weight ratios of the coating materials of the present invention are all above 50% at 600°C, and the residual weight ratios at 1200°C are all above 20%, indicating that the coating materials prepared by the present invention are Intumescent fire retardant coatings have excellent char-forming properties during heating.

3. Thermal conductivity test

Laser flash method: The laser method is used to test the thermal conductivity of the fire-retardant coating at room temperature under the action of a 0.3ms pulse. The average test results are shown in Table 3. It can be seen that the fire-retardant coating prepared by the present invention has good heat insulation. performance.

table 3

4. Adhesion test

Test method: Use the PosiTest adhesion tester to test the adhesion of the fire retardant coating on the steel plate in Example 1-3 according to the CB/T 5210-2006 standard, as shown in Table 4.

Table 4

It can be seen from the data in Table 4 that the adhesion of the fire-retardant coating of the present invention is greater than 2.9MPa, indicating that the fire-retardant coating of the present invention has excellent adhesion.

5. Expanded carbon layer height test

After the combustion back temperature test, a certain corner of the intact coating of Example 3 was randomly cut, and the maximum value h _max and the minimum value h _min of the thickness of the expanded carbon layer of the coating were measured. The test results are shown in Table 5.

table 5

It can be seen from Table 5 that Examples 1-3 of the present invention expanded by 2.5-3.2cm, 2.3-3.6cm, and 2.2-3.4cm respectively at 1200°C. It can be seen that the high heat flow-resistant expansion type fire retardant coating prepared by the examples of the present invention has It has excellent expansion performance after encountering fire, and the thick expanded carbon layer can ideally resist heat flow and prevent the spread of flames.

Figure 3 is a diagram of the expanded carbon layer, which is a physical photo of the test piece of Example 3 after the combustion back temperature test. It can be seen from the picture that after combustion, the coating formed an obvious expanded carbon layer, and the carbon layer was continuous. There is no damage in the distribution, indicating that the coating can produce expansion well, and the carbon layer can withstand high heat flow and block heat flow transfer. The coating has excellent high heat flow resistance.

Each embodiment in this specification is described in a progressive manner. Each embodiment focuses on its differences from other embodiments. The same and similar parts between the various embodiments can be referred to each other. In addition, the inventor of the present case also conducted experiments with other raw materials, process operations, and process conditions mentioned in this specification with reference to the aforementioned embodiments, and all achieved relatively ideal results.

The above description of the disclosed embodiments enables those skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be practiced in other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (10)

1. The high heat flow expansion-resistant fireproof paint is characterized by comprising a primer paint and a top-coating paint;

the weight portions are as follows: the components of the top-coating paint comprise 50-80 parts of epoxy resin, 20-40 parts of epoxy resin modifier, 10-25 parts of flame retardant, 25-45 parts of carbonizing agent, 20-40 parts of foaming agent, 10-30 parts of refractory fiber, 10-40 parts of inorganic filler, 5-15 parts of curing agent, 5-10 parts of defoaming agent and 30-50 parts of organic solvent; the components of the primer coating comprise 70-90 parts of phosphate base stock;

the epoxy resin is F51 type unmodified epoxy resin;

the epoxy resin modifier is polymethylphenylsiloxane;

the phosphate base material consists of aluminum dihydrogen phosphate, zinc oxide, cerium oxide and water.

2. The high heat flow expansion resistant fire retardant coating according to claim 1, wherein the flame retardant comprises at least one of ammonium polyphosphate, phosphoric acid and monoammonium phosphate;

the carbon forming agent comprises one of dipentaerythritol, ethylene glycol and pentaerythritol;

the foaming agent comprises at least one of melamine, melamine phosphate and urea.

3. The high heat flow expansion resistant fire retardant coating according to claim 1, wherein the refractory fibers are chopped fibers forming a size gradient gradation;

the inorganic filler comprises at least one of talcum powder, perlite, expanded graphite, aluminum hydroxide, zirconium boride, hafnium carbide and sepiolite;

the curing agent comprises one of polyamide, alicyclic amine and aliphatic amine;

the defoaming agent is an organosilicon defoaming agent BYK-065;

the organic solvent includes at least one of absolute ethanol, acetone, and neopentyl glycol glycidyl ether.

4. The high heat flow expansion resistant fire retardant coating according to claim 3, wherein said chopped fibers comprise at least one of chopped high silica fibers, chopped alumina fibers and chopped mullite fibers; the gradient grading is composed of refractory fibers with lengths of 6mm, 8mm, 10mm and 12mm, and the mass ratio is 2:2:3:3.

5. the high heat flow expansion resistant fire retardant coating according to claim 1, wherein the mass ratio of aluminum dihydrogen phosphate, zinc oxide, cerium oxide and water in the phosphate base material is 3:1:1:1.

6. a method of preparing the high heat flow expansion resistant fire retardant coating according to any one of claims 1 to 5, comprising:

heating and melting epoxy resin, heating to 70-100 ℃, adding 1/3 of the total amount of an epoxy resin modifier and an organic solvent, and carrying out a modification reaction to obtain modified epoxy resin;

heating the flame retardant and the carbon forming agent for reaction, adding the foaming agent for continuous reaction, grinding and sieving to obtain white solid;

adding refractory fiber, inorganic filler and the balance of organic solvent into the modified epoxy resin, heating and stirring uniformly, and ball milling to obtain a mixed material;

mixing the mixed material with the white solid, adding a curing agent and a defoaming agent, and performing ball milling and dispersing to obtain the surface coating;

carrying out ball milling and dispersing on aluminum dihydrogen phosphate, zinc oxide and cerium oxide in a phosphate base material, and sieving to obtain solid powder;

and under the condition of heating and stirring in a water bath, mixing the solid powder with water, and stirring for reacting to gel to obtain the primer coating.

7. The method according to claim 6, wherein the time for the modification reaction is 0.5 to 1 hour; the temperature of the heating reaction is 120-170 ℃; the grinding and sieving are carried out by sieving with a 100-300 mesh sieve; the temperature of the heating and stirring is 60-90 ℃; the ball milling is carried out for 1-3 hours under the condition of 300-600 r/min.

8. The method of claim 6, wherein the post-dispersion sieving is 100-300 mesh sieving.

9. Use of the high heat flow expansion resistant fire retardant coating according to any one of claims 1-5 in the fire protection of construction steel structures and in the fire protection of new energy batteries.

10. A fire-resistant coating prepared using the high heat flow expansion resistant fire-resistant coating according to any one of claims 1 to 5.