Ceramifiable polyurethane fireproof coating and flame-retardant thermal insulation structure

Abstract

The application discloses a ceramic polyurethane fireproof coating and a fire-retardant and heat-insulating structure, and relates to the technical field of fireproof materials.The ceramic polyurethane fireproof coating is composed of component A and component B.The component A comprises the following raw materials in parts by weight: polyhydric alcohol 40-80 parts, chain extender 0-5 parts, fire-retardant powder 50-65 parts, high-temperature melting and low-temperature adhesive 3-10 parts, powder filler 50-65 parts, liquid viscosity reducer 3-10 parts, and auxiliary agent 0-5 parts; and the component B is isocyanate.The fireproof material can expand to form a hard ceramic shell when heated by fire, so as to insulate the flame and heat, and has a long fire resistance time; when used as a fireproof coating, the fireproof coating can play a good fire-retardant role and effectively prevent the spread of fire.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of fireproof materials, and particularly relates to a ceramicizable polyurethane fireproof coating and a fireproof and heat-insulating structure. BACKGROUND

[0002] With the progress of science and technology and the development of society, various new synthetic materials are widely used in people's life and production. At the same time, people pay more and more attention to safety and environmental protection, and the fireproof and flame-retardant performance of these new materials also attracts people's attention. Among various technologies, fireproof coatings have the advantages of heat insulation, flame retardation, environmental protection, high efficiency, convenient use and low price, and are widely used.

[0003] Generally, when the external temperature of a metal steel structure gradually rises, the mechanical properties and the like will decrease, thereby causing the structure to deform and bend, eventually losing the supporting ability and causing collapse and the like. Therefore, a layer of fireproof coating is generally coated on the surface of the metal steel structure to achieve the purpose of flame retardation and heat insulation. The ultra-thin intumescent steel structure fireproof coating refers to a steel structure fireproof coating with a coating thickness of not more than 3 mm. This kind of steel structure fireproof coating can foam and expand when on fire, and can form a dense fire-resistant and heat-insulating layer with a thickness of more than ten times the thickness of itself. This kind of coating is currently the steel structure fireproof coating favored by users. At present, most of the expandable fireproof coatings are achieved by using expandable graphite to achieve the expansion requirement, but the coating thickness of the fireproof coating generally needs to reach 1.5 mm or more to have the effect of flame retardation and heat insulation. In addition, although some ultra-thin fireproof coatings can achieve a spraying thickness of 200-400 μm, because expandable graphite is added, the coating expansion ratio after expansion under heat reaches 30 times or more, which not only causes the carbon layer itself to be thin and easy to break and crack under the impact of the flame, which is not conducive to the implementation of the effect of flame retardation and heat insulation, but also further limits the use range or field of the fireproof coating.

[0004] In addition, the use conditions of some other ultra-thin fireproof coatings (with a thickness of 1.5-3 mm) themselves limit their use in some other aspects. For example, in a new energy automobile battery pack, due to the size limitation and space requirement, the available space for the fireproof coating of the battery pack in the overall design is small, and the maximum gap after expansion under heat is only 3-7 mm. The existing ultra-thin coating has an expansion ratio of several tens of times or even hundreds of times after expansion under heat. Under heat, the ideal expansion ratio may not be reached due to space first, thereby causing the effect of flame retardation and heat insulation to not meet the requirements, and the ultra-thin fireproof coating is not suitable for compact scenarios such as battery packs.

[0005] Patent CN111117458A discloses a kind of ultra-thin steel structure fireproof paint and preparation method thereof, the fireproof paint although has good adhesion to steel, reduces heat transfer, plays the role of heat insulation, but overall heat insulation effect is still poor, the back temperature of steel is more than 350 DEG C above, since using expanded graphite as expansion agent, when coating is impacted by flame, it is easy to form smoke and the expansion ratio of formed expanded carbon layer is too large, and the strength is low.

[0006] Therefore, it is very necessary to provide a fireproof paint which is ultra-thin (thickness less than 1 mm), expandable (expansion ratio 10-20) and has excellent fire resistance effect. SUMMARY

[0007] In view of the deficiencies of the prior art, the purpose of the present application is to provide a ceramicizable polyurethane fireproof paint and a fire-retardant and heat-insulating structure. The minimum thickness of the fireproof paint is only 350 μm, and the expansion ratio is between 10 and 20. When heated, it can expand to form a hard ceramic shell to isolate flames and heat. It has a long fire resistance time and can play a good fire-retardant role when used as a fireproof paint, effectively preventing the spread of fire. It can not only be used as a fireproof coating for metal steel structures, but also be used as a fireproof coating for compact structures such as battery packs.

[0008] The technical problems solved by the present application are solved by the following technical solutions:

[0009] One of the purposes of the present application is to provide a ceramicizable polyurethane fireproof paint, which is composed of component A and component B.

[0010] The A component includes the following raw materials in parts by weight:

[0011]

[0012] The B component is isocyanate.

[0013] The fire-retardant powder is composed of organic phosphinic acid salt, phosphate and borate in a mass ratio of (4-11):(25-35):(15-27).

[0014] The second purpose of the present application is to provide a fire-retardant and heat-insulating structure, which includes a base structure and a fireproof paint layer coated on the surface of the structure. The fireproof paint layer is prepared from the ceramicizable polyurethane fireproof paint.

[0015] The present application has the following advantages:

[0016] 1、the fireproof coating obtained by adjusting the ratio of each substance in the fire-retardant powder has excellent fire-retardant and fireproof performance, the coating layer with a thickness of 600μm is formed on the 1mm thick Q235 hot-rolled steel, the coating layer is sprayed and burned by the flame with a temperature of 1100-1300℃, the expansion ratio is 10-20 times, the fireproof time of the coating layer is more than 30min, and the temperature of the back of the metal substrate is not more than 350℃ within 30min.

[0017] 2、the fire-retardant powder, the high-temperature melting low-temperature binder and the specific composition and ratio of the powder filler make the fire-retardant grade of the powder material reach V0 level when the adding amount is 45%, and the average value of the bending strength of the porcelainized material is more than 2MPa.

[0018] 3、the solid content of the fireproof coating can be adjusted between 45-65%, and the adhesion and weather resistance of the material itself are less affected. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 the appearance diagram of the sample strip prepared from the fireproof material obtained in example 1 after maturation;

[0020] Figure 2 the appearance and cross-section diagram of the porcelainized sample strip prepared from the fireproof material obtained in example 1 after maturation;

[0021] Figure 3 the appearance diagram of the coating layer formed on the steel plate when the fireproof coating obtained from the fireproof material in example 1 is used, after the surface is sprayed and burned by the flame at 1300℃ for 30min, the ceramic shell is formed on the surface of the fireproof coating after the flame spraying;

[0022] Figure 4 the cross-section diagram of the porcelainized sample strip prepared from the fireproof material obtained in comparative example 14 after maturation;

[0023] Figure 5 the appearance diagram of the porcelainized sample strip prepared from the fireproof material obtained in comparative example 16 after maturation. DETAILED DESCRIPTION

[0024] In order to make the technical means, creative features, purposes and effects of the present application easy to understand, the present application is further described in combination with specific examples and drawings.

[0025] The present application provides a ceramicizable polyurethane fireproof coating, which is composed of component A and component B.

[0026] The component A includes the following raw materials in parts by weight:

[0027]

[0028] The B component is isocyanate;

[0029] The flame-retardant powder is composed of organic phosphite, phosphate and borate in a mass ratio of (4-11):(25-35):(15-27).

[0030] In the present application, the polyol is selected from at least one of polyoxypropylene glycol, polytrimethylene ether glycol, polytetrahydrofuran ether glycol, polycarbonate glycol, castor oil polyol, soybean oil polyol and palm oil polyol, preferably at least one of castor oil polyol with a functionality of 2-4.

[0031] In the present application, the isocyanate is a polyphenyl polymethylene polyisocyanate.

[0032] In the present application, the chain extender is selected from at least one of diethylene glycol, neopentyl glycol, trimethylolpropane, dimethylolpropionic acid and dimethylolbutyric acid.

[0033] In some preferred embodiments of the present application, the organic phosphite is selected from at least one of aluminum diethylphosphinate, aluminum isobutylphosphinate and aluminum diisobutylphosphinate; preferably, the phosphate is selected from at least one of ammonium polyphosphate, silane-coated ammonium polyphosphate, melamine-coated ammonium polyphosphate; preferably, the borate is selected from at least one of sodium borate, ammonium borate, aluminum borate and zinc borate.

[0034] In the present application, the high-temperature melting low-temperature binder is a low-melting-point glass powder, preferably a glass powder with an initial melting point of 380-400℃.

[0035] In the present application, the powder filler is selected from at least one of aluminum phosphate, calcium silicate, silicon powder, kyanite powder and molecular sieve powder.

[0036] In a further technical solution, the molecular sieve powder is 4A type molecular sieve activated powder with a particle size of 1.6-2.5μm.

[0037] In the present application, the liquid viscosity reducer is selected from at least one of dioctyl terephthalate, dioctyl phthalate, triethyl phosphate and tributyl phosphate.

[0038] In the present application, the auxiliary agent includes a catalyst and a defoaming agent.

[0039] In a further technical solution, the catalyst is selected from at least one of organic tin catalyst and organic bismuth catalyst, preferably organic tin catalyst such as dibutyl tin dilaurate and stannous octoate; the defoaming agent is selected from at least one of BYK-1790, BYK-066N and BYK-555.

[0040] The application further provides a preparation method of the ceramicizable polyurethane fireproof coating, comprising the following steps:

[0041] S1, the fire-retardant powder, high-temperature melting low-temperature binder and powder filler are weighed according to the proportion, mixed uniformly, dried and dehydrated to obtain a powder material;

[0042] S2, the polyol, chain extender, powder material, liquid viscosity reducer and auxiliary agent are weighed according to the proportion, mixed uniformly, vacuum defoamed to obtain component A, and sealed and stored;

[0043] S3, the isocyanate is weighed and recorded as component B;

[0044] S4, when used, the components A and B are mixed uniformly according to the set R value, and then the construction can be performed.

[0045] The skilled in the art can determine the value range of the R value according to the actual situation, for example, the R value can be 1-1.2:1, and exemplarily, the R value can be 1.05:1.

[0046] The application further provides a fire-retardant and heat-insulating structure, comprising a base structure and a fireproof coating layer coated on the surface of the base structure, wherein the fireproof coating layer is prepared from the ceramicizable polyurethane fireproof coating. Preferably, the expansion ratio of the fireproof coating layer is 10-20 times.

[0047] Preferably, the base structure is a metal steel structure or a battery pack.

[0048] According to the application, the ceramicizable polyurethane fireproof coating can be used as a fireproof coating for steel structures, and can also be used as a fireproof coating for compact structures such as battery packs. The skilled in the art can select a suitable thickness according to the actual application scene. When used as a fireproof coating for indoor thin steel structures, the thickness of the fireproof coating layer can be at least 350 microns, for example, 350 microns, 400 microns, 500 microns, 600 microns, 800 microns, 1 mm, 2 mm, 3 mm or thicker.

[0049] The inventors of the application find that the expansion ratio of the ceramicizable polyurethane fireproof coating after expansion should be controlled within the range of 10-20 times. When the expansion ratio of the carbon layer is less than 10 times, the gap between the carbon layer and the bottom metal material is small, and the heat-insulating effect is poor. When the expansion ratio of the carbon layer exceeds 20 times, on the one hand, the carbon layer itself is too thin and is easy to break and crack under the impact of the flame, which is not conducive to fire-retardant and heat-insulating, and on the other hand, it is not suitable for special scene applications. Therefore, the expansion ratio of the carbon layer of the coating of the application is controlled within the range of 10-20 times.

[0050] The inventors of the present application also found that the ceramicizable polyurethane fireproof coating can be applied in some fireproof fields which limit the coating thickness and expansion ratio, and can be a new energy battery pack fireproof coating: the coating itself has a thin coating thickness (350-1000 μm), the carbon layer has an expansion ratio of 10-20 times after heat expansion, the surface strength is high after being turned into porcelain by heat, the fireproof and heat insulation effects are prominent (the steel plate back temperature is less than 350℃ after 30 min of flame impact).

[0051] The preparation method of the fireproof and heat insulation structure is as follows: the ceramicizable polyurethane fireproof coating prepared in the present application is coated on a base structure as a coating, so that a fireproof coating is formed, which can expand to form a hard ceramic shell when heated by fire, so as to insulate the flame and heat, and effectively reduce the back temperature of the metal substrate, thereby protecting the metal substrate well.

[0052] The performance test method of the fireproof material is as follows:

[0053] The fireproof performance and bending strength test: the fireproof material is poured into a mold with a size of 150*150*3mm and cured (60℃ / 3h), and then demolded to obtain a sample. The fireproof performance of the sample is determined according to GB / T 2408. Five sample strips with a size of 80*10*3mm are cut, and are calcined in a muffle furnace at 950℃ for 45 min. The sample strips to be tested are obtained; the sample strips to be tested are knocked to hear whether there is a ceramic sound, and if yes, the sample strips are ceramic, and if not, the sample strips are not ceramic; then the bending strength of the sample strips is determined according to GB / T 14452-93, and the average value of the five sample strips is taken.

[0054] The fire resistance time and back temperature test: the fireproof coating is coated on a 1mm thick Q235 hot-rolled steel to form a coating with a thickness of 600μm, and after the coating is completely cured, a spray gun with a flame temperature of 1300℃ is used to spray and burn until the surface carbon layer is damaged and a cavity appears, and the spray time at this time is recorded as the fire resistance time; a thermocouple is used to measure the change of the back temperature of the steel plate, and the highest temperature before the surface carbon layer is damaged is recorded as the highest back temperature, and the state of the surface carbon layer and the expanded thickness H1 of the carbon layer are observed and measured.

[0055] The carbon layer expansion ratio test: the thickness H0 of the fireproof coating is measured first, and then the thickness H1 of the carbon layer after expansion by flame spraying is measured, and the carbon layer expansion ratio is calculated by the ratio of the height of the expanded carbon layer to the thickness of the coating, and the calculation formula is as follows: carbon layer expansion ratio = H1 / H0.

[0056] Example 1

[0057] The fireproof material is prepared according to the raw material composition and ratio in Table 1, including the following steps:

[0058] S1, the flame-retardant powder, high-temperature melting low-temperature binder and powder filler were weighed according to the ratio, mixed at 1000 r / min for 10 min, and dried at 105°C for 24 h to remove water to obtain the powder material;

[0059] S2, the polyol, chain extender, powder material, liquid viscosity reducer and auxiliary agent were weighed according to the ratio, mixed at 2000 r / min for 5 min, and vacuum degassed to obtain component A, which was sealed and stored;

[0060] S3, isocyanate was weighed and denoted as component B;

[0061] S4, when used, components A and B were mixed at 2000 r / min for 4 min according to the set R value = 1.05, and then construction was performed.

[0062] The total addition amount of the powder material in this embodiment was 55%.

[0063] Table 1

[0064]

[0065]

[0066] Examples 2-5 and Comparative Examples 1-2

[0067] According to the method of Example 1, except that the total addition amount of the powder material (the composition of the powder material and the ratio of each component were unchanged) was different, which was shown in Table 2.

[0068] Table 2

[0069]

[0070] From Table 2, it can be seen that: (1) with the increase of the total addition amount of the powder material, the bending strength and fire resistance time of the coating had a trend of increasing; (2) when the total addition amount of the powder material was 55%, the porcelain strength and heat insulation effect were the best; (3) when the total addition amount of the powder material was 45%, the flame-retardant grade of the coating could reach V0 level, and the bending strength reached 2.52 MPa; (4) when the total addition amount of the powder material was 40%, the flame-retardant grade of the coating was only V1 level, although the strength after porcelainization also exceeded 2 MPa, but the heat insulation effect and fireproof performance were poor; (5) with the increase of the total addition amount of the powder material, the carbon layer expansion ratio gradually decreased, and the fire resistance time gradually increased, because the more the powder content in the coating of the same thickness, the longer the fire resistance time, and the carbon layer expansion ratio decreased; (6) when the total addition amount of the powder material exceeded 65% to 70%, the dispersion effect of the powder material in component A was poor, the overall dispersion was uneven, the viscosity increased, which led to the subsequent use.

[0071] The appearance of the sample bar prepared from the fireproof material obtained in Example 1 after maturation is shown in Figure 1 The appearance and cross section of the sample bar after vitrification are shown in Figure 2 It can be seen from Figure 1 and Figure 2 that the fireproof material can expand to form a hard ceramic shell and the cellular structure is complete after calcination in a muffle furnace at a vitrification condition of 950℃ / 45min, which can well play a role in isolating flame and heat.

[0072] The appearance of the coating layer formed on the steel plate by using the fireproof material obtained in Example 1 as a fireproof coating after flame spraying on the surface of the coating layer at 1300℃ for 30min is shown in Figure 3 It can be seen from Figure 3 that the coating layer expands to form a hard ceramic shell after flame spraying on the surface of the coating layer at 1300℃ for 30min, which prevents the spread of fire and effectively reduces the back temperature of the steel plate, thereby achieving excellent protection effect on the steel plate.

[0073] Examples 6-14 and Comparative Examples 3-6

[0074] The method of Example 1 was used, except that the weight fraction of the silane-coated crystalline type II ammonium polyphosphate (APP) in the flame-retardant powder was gradually increased from 25 parts to 35 parts, and the amounts of aluminum diethylphosphinate (ADEP) and zinc borate were as shown in Table 3 (the total amount of the flame-retardant powder was unchanged).

[0075] Table 3

[0076]

[0077] It can be seen from Table 3 that when the weight fraction of APP is gradually increased from 25 to 35, and the weight fractions of ADEP and zinc borate are increased or decreased accordingly, the fireproof material can achieve a flame-retardant grade of V0 level, the surface of the carbon layer is ceramicized after flame spraying, and the carbon layer has a good expansion ratio; this is mainly because APP is decomposed by heat to generate phosphoric acid and pyrophosphoric acid with strong dehydration effect, which makes the polyurethane coating dehydrate and carbonize, and the water vapor and non-combustible gas generated by the reaction make the carbon layer expand, and finally form a layer of microporous expanded carbon layer, which isolates air and heat conduction, protects the polymer main body, and achieves the purpose of flame retardation, thereby improving the flame-retardant effect. Among them, the nitrogen-containing compound plays the role of foaming agent and coke reinforcing agent.

[0078] In addition, when the ratio of the amounts of ADEP, APP and zinc borate is 5:29:22, the fire-retardant and heat-insulating effect of the fireproof coating is optimal. In this case, as shown in Example 1, Example 7 and Example 11, even if the total amount of the fire-retardant powder and the ratio of ADEP and zinc borate in the fire-retardant powder are kept unchanged, adjusting the amount of APP in the composition (the composition of ADEP and zinc borate) will reduce the fire-retardant and heat-insulating effect of the fireproof coating.

[0079] Examples 15-18 and Comparative Examples 7-9

[0080] The method of Example 1 was followed, except that the amount of ADEP in the fire-retardant powder was gradually increased from 4 to 11 parts by weight, and the amounts of APP and zinc borate were as shown in Table 4 (the total amount of the fire-retardant powder was kept unchanged).

[0081] Table 4

[0082]

[0083]

[0084] As can be seen from Table 4, the fire-retardant grade of the fireproof material added with ADEP can all reach the V0 level. This is because ADEP is first decomposed to generate phosphoric acid, metaphosphoric acid and the like in the process of flame combustion, and then the metaphosphoric acid continues to polymerize to generate poly-metaphosphoric acid. In this process, not only does the covering layer generated from phosphoric acid play a covering effect, but also the generated poly-metaphosphoric acid, which is a strong acid and a very strong dehydrating agent, causes the polyurethane coating to dehydrate and carbonize, changes the mode of the polymer combustion process and forms a carbon film on the surface to insulate air, thereby playing a stronger fire-retardant effect. In addition, free radicals PO· exist throughout the combustion process, which can combine with hydrogen atoms in the flame area to inhibit the flame, thereby better playing a fire-retardant effect.

[0085] As can be seen from Table 4, when the ratio of the amounts of ADEP, APP and zinc borate is 5:29:22, the fire-retardant and heat-insulating effect of the fireproof coating is optimal. In this case, as shown in Example 7, Example 14 and Example 15, even if the total amount of the fire-retardant powder and the amount of ADEP are kept unchanged, changing the ratio of APP and zinc borate will reduce the fire-retardant and heat-insulating effect of the fireproof coating.

[0086] Comparative Examples 10-12

[0087] The method of Example 1 was followed, except that the amount of zinc borate in the fire-retardant powder was gradually increased from 15 to 27 parts by weight, and the amounts of ADEP and APP were as shown in Table 5 (the total amount of the fire-retardant powder was kept unchanged).

[0088] Table 5

[0089]

[0090]

[0091] As can be seen from Table 5, when the amount of zinc borate is 15-27 parts, the porcelain state and bending strength of the fireproof material are both good, because zinc borate begins to release crystal water at 300°C, and forms a solid phase cover layer to isolate the surrounding oxygen, prevent the flame from continuing to burn and have a smoke suppression effect; in addition, zinc borate can also synergistically flame retard with ADEP and increase the strength of the carbon layer, and has a good promoting effect on the flame retardant effect.

[0092] In addition, when the amount ratio of ADEP, APP and zinc borate is 5:29:22, the flame-retardant and heat-insulating effect of the fireproof coating is optimal, and even if the total amount of the flame-retardant powder and the ratio of ADEP and APP in the flame-retardant powder are kept unchanged, adjusting the amount of zinc borate and the composition (combination of ADEP and APP) will reduce the flame-retardant and heat-insulating effect of the fireproof coating, as shown in Example 1, Example 6 and Example 14.

[0093] As can also be seen from Table 4, when the amount ratio of ADEP, APP and zinc borate is 5:29:22, the flame-retardant and heat-insulating effect of the fireproof coating is optimal. Even if the total amount of the flame-retardant powder and the amount of zinc borate are kept unchanged, changing the ratio of APP and ADEP will reduce the flame-retardant and heat-insulating effect of the fireproof coating, as shown in Example 1 and Comparative Examples 10-11.

[0094] From Tables 3-5, it can be seen that, when the total amount of the powder material and the components are unchanged, controlling the weight ratio of ADEP, APP and zinc borate in the flame-retardant powder in the range of (4-11):(25-35):(15-27) can make the fireproof material reach the V0 flame-retardant level, and the bending strength after calcination into porcelain in a muffle furnace is more than 2 MPa on average, the fire resistance time is more than 30 min, the back temperature of the steel plate is not more than 350°C, and the expansion ratio of the expanded carbon layer is 10-20 times. When the three powder materials in the flame-retardant powder are increased or decreased respectively to more than the above-mentioned ratio, the flame-retardant and / or heat-insulating effect of the coating cannot reach the design expectation. This is because, in the process of burning the coating, ADEP mainly plays a role in inhibiting the combustion reaction by releasing free radicals, APP mainly plays a role in condensed phase flame retardation by forming an expanded carbon layer to increase the amount of residual carbon, and the addition of zinc borate can react with ADEP to generate boron-aluminum compounds to increase the carbon layer; and there is a good synergistic flame-retardant effect among the three, and finally the low-melting-point glass powder binds the powder at high temperature without melting, and forms a hard ceramic shell to further isolate the flame and heat conduction. Therefore, the change of the content of any of the three flame-retardant powder materials will have different effects on the overall flame retardation and porcelain formation.

[0095] Comparative Example 13

[0096] The method of Example 1 was followed, except that 6 parts of expandable graphite was also added to the fireproof coating. The specific raw material composition and ratio and product performance are shown in Table 6.

[0097] Table 6

[0098] Expandable graphite Ceramming Carbon layer expansion ratio Fire resistance time Maximum back temperature of steel sheet Unit Part / / min ℃ Example 1 0 Yes 16.2 46 294 Comparative Example 13 6 No 65.4 34 486

[0099] As can be seen from Table 6, after adding expandable graphite to the ceramicizable polyurethane fireproof coating, although the fire resistance time of the fireproof coating is not greatly affected, the expansion ratio of the carbon layer is increased to 65.4, resulting in a decrease in the overall thickness of the carbon layer and a decrease in the surface strength of the carbon layer, which cannot completely form a ceramic shell, and the overall fireproof and heat insulation effect is reduced, with a steel plate back temperature increase of 486°C, which is significantly lower than that of Example 1.

[0100] Examples 19-22 and Comparative Examples 14-17

[0101] The method of Example 1 was followed, except that the weight fractions of the high-temperature melting low-temperature binder, the powder filler, and the fire-retardant powder were adjusted (the total amount of the powder material and its components were unchanged), as shown in Table 7.

[0102] Table 7

[0103]

[0104]

[0105] As can be seen from Table 7:

[0106] (1) Compared with Example 1, Examples 19 and 20 respectively reduce and increase the low-melting glass powder content to the limit of the ratio, and although the comprehensive performance of the obtained fireproof material also meets the design requirements, the fire-retardant and heat insulation effect of the obtained fireproof coating is significantly worse;

[0107] (2) Comparative Example 14 shows that when no low-melting glass powder is added, i.e., in the absence of a high-temperature melting low-temperature binder, although the ceramic bending strength of the sample is good and the overall fire-retardant grade also reaches the V0 level, the fire resistance time is short and the carbon layer expansion ratio is small, and the overall effect is poor, because in the absence of low-melting glass powder, a high-temperature binder is needed to bind the powder that does not melt at high temperatures into a whole during flame spraying, and because the gas generated by the fire-retardant powder easily escapes, the carbon layer expansion ratio is reduced ( Figure 3 ), and cavities are easily produced under the impact of the flame, affecting the fire resistance time of the coating;

[0108] ​(3) In the comparative example 15, the content of low melting point glass powder is increased, but the low melting point glass powder itself is not flame-retardant, which leads to the decrease of the flame-retardant grade of the coating and the back temperature of the steel plate exceeding 350°C;

[0109] (4) In the comparative example 16, the content of the powder filler is decreased, which leads to the increase of the content of the flame-retardant powder in the fireproof material, the expansion of the coating after being fired at high temperature is too large Figure 4 ), the shape cannot be maintained, the bending strength is low, the carbon layer is thin and fragile, and the temperature resistance time is short;

[0110] (5) In the comparative example 17, the content of the powder filler is increased, the sample maintains the shape after being fired, but the whole is fluffy and cannot be fired, in addition, the flame-retardant effect is decreased and the fire resistance time is shortened.

[0111] Example 23

[0112] According to the method of example 1, except that the thickness of the coating is 350 μm.

[0113] Table 8

[0114] Coating thickness Ceramming Carbon layer expansion ratio Fire resistance time Maximum back temperature of steel sheet Unit pm / / min ℃ Example 1 600 Yes 16.2 46 294 Example 23 350 Yes 19.2 31 348

[0115] From table 8, it can be seen that when the thickness of the coating is decreased from 600 μm to 350 μm, the maximum back temperature of the steel plate is close to but less than 350°C within the effective fire resistance time, the expansion ratio of the carbon layer reaches 19.2 times, and the heat conduction of the flame can be effectively prevented.

[0116] Example 24

[0117] According to the method of example 1, the amount and composition of the powder material are kept unchanged, the R value is kept unchanged at 1.05:1, except that the amount of the liquid component is adjusted, which is shown in table 9.

[0118] Table 9

[0119]

[0120] The fire resistance performance test is shown in table 10.

[0121] Table 10

[0122] Coating thickness Ceramming Carbon layer expansion ratio Fire resistance time Maximum back temperature of steel sheet Unit pm / / min ℃ Example 1 600 Yes 16.2 46 294 Example 24 600 Yes 15.9 39 336

[0123] From table 10, it can be seen that the decrease of the amount of the liquid viscosity reducer has the greatest influence on the viscosity of the coating, and has little influence on the fire resistance performance.

[0124] The above shows and describes the basic principles and main features of the present application and the advantages of the present application. Those skilled in the art should understand that the present application is not limited to the above embodiments, and the above embodiments and descriptions in the specification are only to illustrate the principles of the present application. Without departing from the spirit and scope of the present application, various changes and improvements can be made to the present application, and these changes and improvements all fall within the scope of the claimed present application. The scope of protection of the present application is defined by the appended claims and their equivalents.

Claims

1. A ceramifiable polyurethane fireproofing coating consisting of a component A and a component B, characterized in that: The A component comprises raw materials in the following weight proportions: Polyol 40-80 parts Chain extender 0-5 parts Flame-retardant powder 50-65 parts Low-melting-point glass powder 3-10 parts Powder filler 50-65 parts Liquid viscosity reducer 3-10 parts Auxiliary agent 0-5 parts The B component is isocyanate. The flame-retardant powder is composed of organic phosphite, phosphate and borate in a mass ratio of (4-11) : (25-35) : (15-27).

2. The ceramifiable polyurethane fireproofing coating according to claim 1, characterized in that, The organic phosphite is at least one of diethylaluminum phosphite, isobutylaluminum phosphite and diisobutylaluminum phosphite.

3. The ceramifiable polyurethane fireproofing coating of claim 1, wherein, The phosphate is at least one of crystalline type II ammonium polyphosphate and melamine-coated ammonium polyphosphate.

4. The ceramifiable polyurethane fireproofing coating of claim 1, wherein, The borate is at least one of sodium borate, ammonium borate, aluminum borate and zinc borate.

5. The ceramifiable polyurethane fireproofing coating of claim 1, wherein, The low-melting-point glass powder has an initial melting point of 350-400℃.

6. The ceramifiable polyurethane fireproofing coating of claim 1, wherein: The polyol is at least one of polyoxypropylene glycol, polytrimethylene ether glycol, polytetrahydrofuran ether glycol, polycarbonate glycol, castor oil polyol, soybean oil polyol and palm oil polyol.

7. The ceramifiable polyurethane fireproofing coating of claim 6, wherein: The polyol is at least one of castor oil polyols with a functionality of 2-4.

8. The ceramifiable polyurethane fireproofing coating of claim 1, wherein: The isocyanate is polyphenyl polymethylene polyisocyanate.

9. The ceramifiable polyurethane fireproofing coating of claim 1, wherein: The chain extender is at least one of diethylene glycol, neopentyl glycol, trimethylolpropane, dimethylolpropionic acid and dimethylolbutyric acid.

10. The ceramifiable polyurethane fireproofing coating of claim 1, wherein: The powder filler is at least one of aluminum phosphate, calcium silicate, silicon powder, kyanite powder and molecular sieve powder.

11. The ceramifiable polyurethane fireproofing coating of claim 1, wherein: The liquid viscosity reducer is at least one of dioctyl terephthalate, dioctyl phthalate, triethyl phosphate and tributyl phosphate.

12. The ceramifiable polyurethane fireproofing coating of claim 1, wherein: The auxiliary agent comprises a catalyst and a defoaming agent.

13. The ceramifiable polyurethane fireproofing coating of claim 12, wherein: The catalyst is at least one of organic tin catalyst and organic bismuth catalyst.

14. The ceramifiable polyurethane fireproofing coating of claim 12, wherein: The defoaming agent is at least one of BYK-1790, BYK-066N and BYK-555.

15. A fire-retardant and heat-insulating structure comprising a base structure and a fireproof paint layer coated on the surface of the base structure, characterized in that, The fireproof coating layer is prepared from the ceramicizable polyurethane fireproof coating material according to any one of claims 1-14.

16. The fire resistant thermal barrier structure of claim 15, wherein, The thickness of the fireproof coating layer is greater than 350μm.

17. The fire resistant thermal barrier structure of claim 15, wherein, The expansion ratio of the fireproof coating layer is 10-20 times.

18. The fire resistant thermal barrier structure of claim 15, wherein, The base structure is a metal steel structure or a battery pack.

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