Environmentally friendly organic silicon intumescent fire retardant coating for substations or converter stations, preparation method and application thereof

Abstract

The invention discloses a kind of environmentally friendly organosilicon intumescent fire retardant coating for transformer substation or converter station and its preparation method and application, the raw material of coating includes organosilicon resin 30 60 parts, intumescent flame retardant 30 45 parts, modified glass powder 5 10 parts, inorganic filler 2 20 parts, auxiliary agent 2 10 parts, curing agent 5 25 parts by mass;The intumescent flame retardant uses phosphazene compound as gas source and acid source;The phosphazene compound is formed by hexachlorocyclotriphosphazene and melamine or dicyandiamide undergoing nucleophilic substitution reaction;The modified glass powder is modified by silane coupling agent after mixing with a variety of glass powders having a melting point of 350 ℃ 700 ℃. In the present invention, the high temperature resistance of organosilicon resin coating is improved by formula design, so as to enhance the service life of steel in high temperature scenes, improve the performance reliability of fire protection facilities in transformer substation or converter station, thereby achieving the purpose of high temperature resistance.

Description

Technical Field

[0001] The present invention relates to the technical field of fire retardant coatings, and in particular to an environmentally friendly organic silicon intumescent fire retardant coating for a transformer substation or a converter station, and a preparation method and application thereof. Background Art

[0002] With the rapid development of ultra-high voltage (UHV) power transmission in my country, fire protection capabilities in UHV stations have become an unavoidable issue. UHV transformers store over 100 tons of oil, and once a fire occurs, flame temperatures can reach over 1200°C. Conventional fire-retardant coatings cannot withstand such high temperatures. Furthermore, with increasingly stringent environmental protection requirements, coatings are increasingly using green and environmentally friendly materials.

[0003] The heat resistance of high-temperature coatings is closely related not only to the base resin but also to the type and content of heat-resistant pigments and fillers used. Pure silicone resins are typically only heat-resistant to 200-300°C. Adding appropriate pigments and fillers can produce coatings capable of withstanding temperatures of 300-700°C. Commonly used heat-resistant pigments and fillers include SiC, ZrO2, Al2O3, TiO2, SiO2, ZnO, mica powder, talc, kaolin, aluminum powder, chromium black, and glass powders of varying melting points. Commonly used solvents include aromatic hydrocarbons, esters, alcohols, and ketones, such as xylene, butyl acetate, butanol, and cyclohexanone. Currently, the performance characteristics of conventional silicone coatings are no longer sufficient to meet the demands of the rapidly evolving industry. Intumescent fire-retardant coatings are applied to substrates and, when exposed to fire, react to form a char layer much thicker than the original coating, thereby reducing heat transfer to the substrate and improving the fire resistance of the protected substrate. Therefore, for application scenarios such as fire substations, based on the principle of expansion flame retardancy, it is expected to further improve the high temperature resistance of silicone coatings (temperature resistance not less than 1200°C). Summary of the Invention

[0004] The technical problem to be solved by the present invention is how to improve the high temperature resistance of the silicone resin coating to meet the performance requirements of fire protection facilities in substations and converter stations.

[0005] The present invention solves the above technical problems through the following technical means:

[0006] An environmentally friendly organic silicon intumescent fire retardant coating for a transformer substation or a converter station, wherein the raw materials thereof include, by weight, 30-60 parts of an organic silicon resin, 30-45 parts of an intumescent flame retardant, 5-10 parts of modified glass powder, 2-20 parts of an inorganic filler, 2-10 parts of an auxiliary agent, and 5-25 parts of a curing agent;

[0007] The intumescent flame retardant uses a phosphazene compound as a gas source and an acid source; the phosphazene compound is formed by a nucleophilic substitution reaction between hexachlorocyclotriphosphazene and melamine or dicyandiamide;

[0008] The modified glass powder is prepared by mixing a plurality of glass powders with melting points of 350° C. to 700° C. and then modifying the mixture with a silane coupling agent.

[0009] Preferably, the silicone resin is an epoxy-modified silicone resin.

[0010] Preferably, the acid source of the intumescent flame retardant further includes ammonium polyphosphate, ammonium polyphosphate or a mixture of the two.

[0011] Preferably, the mass ratio of ammonium polyphosphate, a mixture of one or both of ammonium polyphosphate and the phosphazene compound is 1-2:1-2.

[0012] Preferably, the carbon source of the intumescent flame retardant is a mixture of one or more of pentaerythritol, dipentaerythritol, starch, and expanded graphite.

[0013] Preferably, the carbon source of the intumescent flame retardant is pentaerythritol.

[0014] Preferably, the mass ratio of the phosphazene compound to the intumescent flame retardant carbon source is 1-4:1.

[0015] Preferably, the modified glass powder is formed by mixing three glass powders with melting points of 350° C., 500° C., and 700° C. and then modifying the mixture with a silane coupling agent.

[0016] Preferably, the mass ratio of the three glass powders with melting points of 350° C., 500° C., and 700° C. is 1:1:1.

[0017] Preferably, the preparation process of the modified glass powder includes the following steps: grinding and sieving a variety of glass powders with melting points of 350°C-700°C, mixing and ball milling, mixing with ethanol and water, adding a silane coupling agent, heating for reaction, and drying to obtain the modified glass powder.

[0018] Preferably, the heating reaction temperature is 60° C. and the time is 12 h.

[0019] Preferably, the silane coupling agent is an amino-functional silane coupling agent.

[0020] Preferably, the silane coupling agent is silane coupling agent KH-570.

[0021] Preferably, the mass ratio of the silane coupling agent to the glass powder is 1:1-5.

[0022] Preferably, the inorganic filler is a mixture of one or more of talc, Mxene, graphene, expanded graphite, vermiculite, Al2O3, and nano-titanium dioxide.

[0023] Preferably, the inorganic filler is talc powder, expanded graphite or a mixture of the two.

[0024] Preferably, the auxiliary agent is an adhesion promoter.

[0025] Preferably, the adhesion promoter includes a mixture of one or more of polyester phosphate 5063A adhesion promoter, 5140B water-based adhesion promoter, and AKN-6618 adhesion promoter.

[0026] Preferably, the curing agent is a mixture of one or more of polyurethane, amino compound, and organopolysilazane.

[0027] Preferably, the raw materials of the environmentally friendly organic silicon intumescent fire retardant coating for the substation or converter station also include water.

[0028] Preferably, the mass ratio of the silicone resin to water is 3-5:5-7.

[0029] The present invention also proposes a method for preparing the environmentally friendly organic silicon intumescent fire retardant coating for substations or converter stations, comprising the following steps: mixing an inorganic filler, an intumescent flame retardant and a modified glass powder by ball milling to obtain a composite filler; preparing an aqueous solution of an organic silicon resin, adding the composite filler and an auxiliary agent, heating and stirring, and then adding a curing agent and stirring to obtain the environmentally friendly organic silicon intumescent fire retardant coating for substations or converter stations.

[0030] Preferably, the mass concentration of the organic silicone resin aqueous solution is 30-50%.

[0031] Preferably, the curing agent is added after heating to 50° C. and stirring for 60 minutes.

[0032] The present invention also provides a coating, which is prepared using the environmentally friendly organic silicon intumescent fire retardant coating for transformer substations or converter stations.

[0033] The present invention also proposes an application of the environmentally friendly organic silicon intumescent fire retardant coating for a transformer substation or a converter station in the transformer substation or the converter station.

[0034] The advantages of the present invention are:

[0035] In the present invention, the high temperature resistance of the silicone resin coating is improved through formula design, so as to enhance the service life of steel in high temperature scenarios and improve the performance reliability of fire protection facilities in substations or converter stations, thereby achieving the purpose of high temperature resistance.

[0036] The environmentally friendly organic silicon intumescent fire retardant coating provided by the present invention can withstand temperatures of 1200°C in the short term and 700°C in the long term, and will not generate a large amount of toxic gas and smoke when burned.

[0037] In the present invention, the modified glass powder significantly impacts the coating's high-temperature resistance. The high-temperature-resistant inorganic filler, in synergy with the silicone resin, can enhance the coating's high-temperature resistance. The addition of an adhesion promoter improves both the coating's adhesion and dispersibility. The present invention effectively enhances the coating's high-temperature resistance through the synergistic combination of the silicone resin, intumescent flame retardant, modified glass powder, and high-temperature-resistant inorganic filler.

[0038] The present invention utilizes an intumescent flame retardant system and realizes secondary film formation of an organic silicon intumescent flame retardant coating at high temperature by compounding and modifying glass powders with different melting points, thereby improving the high temperature resistance of the organic silicon intumescent flame retardant coating.

[0039] The coating of the present invention has a simple and environmentally friendly preparation process. The functional filler used in the coating is thoroughly mixed by ball milling an intumescent flame retardant, a high-temperature-resistant inorganic filler, and modified glass powder. The filler and silicone resin are then fully reacted using an aqueous solution and a silane coupling agent. The coating preparation process and components are both environmentally friendly and harmless to the human body.

[0040] The environmentally friendly organic silicon intumescent fire-retardant coating prepared by the present invention has a temperature resistance of 1200° C., generates an intumescent flame-retardant carbon layer, and can play a good fire-proofing role on the base material.

[0041] The organic silicon intumescent fire retardant coating prepared by the present invention can be cured at room temperature. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 is an infrared spectrum of the phosphazene compound prepared in Example 1 of the present invention;

[0043] Figure 2 is the XRD spectrum of the phosphazene compound prepared in Example 1 of the present invention;

[0044] Figure 3 is the thermogravimetric curve of the phosphazene compound prepared in Example 1 of the present invention;

[0045] Figure 4 is a scanning electron microscope image of the phosphazene compound prepared in Example 1 of the present invention;

[0046] Figure 5 This is a back temperature test diagram of the organosilicon intumescent fire retardant coating prepared in Examples 1-4 of the present invention;

[0047] Figure 6 This is a digital image of the coating and char layer of the organosilicon intumescent fire retardant coating prepared in Example 1 of the present invention;

[0048] Figure 7 The digital image (left) and scanned image (right) of the expanded carbon layer of the organosilicon intumescent fire retardant coating prepared in Example 2 of the present invention;

[0049] Figure 8 This is a digital image of the coating of the fire retardant coating prepared in Comparative Example 2 of the present invention;

[0050] Figure 9 This is a back temperature test diagram of the coatings prepared in Comparative Examples 1-7 of the present invention. DETAILED DESCRIPTION

[0051] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0052] Unless otherwise specified, the test materials and reagents used in the following examples can be obtained from commercial sources.

[0053] If no specific techniques or conditions are specified in the examples, they can be carried out according to the techniques or conditions described in the literature in the field or according to the product instructions.

[0054] In the following examples and comparative examples, the melting point of the glass powder is the temperature at which the glass powder begins to melt;

[0055] The glass powder with a melting point of 350°C is GT-35 low-melting-point glass powder, and the manufacturer is Anmi Micro-Nano New Materials (Guangzhou) Co., Ltd.

[0056] The glass powder with a melting point of 500°C is GT-50 low-melting-point glass powder, manufactured by Anmi Micro-Nano New Materials (Guangzhou) Co., Ltd.

[0057] The glass powder with a melting point of 700°C is GT-70 low-melting-point glass powder, and the manufacturer is Anmi Micro-Nano New Materials (Guangzhou) Co., Ltd.

[0058] The SJ-804 epoxy modified silicone resin is sourced from Zongyang County Sanjin Pigment Co., Ltd.

[0059] The polyurethane curing agent is WANNATE HT-100 produced by Wanhua Chemical Group Co., Ltd.

[0060] The polyester phosphate 5063A adhesion promoter is sourced from Guangdong Nuoyi Chemical Co., Ltd.

[0061] Example 1

[0062] Disclosed is an environmentally friendly organic silicon intumescent fire retardant coating for use in substations or converter stations. The raw materials thereof include, by weight, 40 parts of SJ-804 epoxy-modified organic silicon resin, 40 parts of intumescent flame retardant, 8 parts of modified glass powder, 5 parts of talc, 4 parts of polyester phosphate 5063A adhesion promoter, and 10 parts of polyurethane curing agent.

[0063] Among them, the intumescent flame retardant is a phosphazene compound as an integrated gas source and acid source, ammonium polyphosphate as an acid source, and pentaerythritol as a carbon source. The mass ratio of the phosphazene compound, ammonium polyphosphate and pentaerythritol is 2:2:1.

[0064] The preparation steps of the phosphazene compound are as follows: hexachlorocyclotriphosphazene and melamine (the mass ratio of hexachlorocyclotriphosphazene to melamine is 1:1) are refluxed in a pyridine solution (the mass concentration of hexachlorocyclotriphosphazene in the pyridine solution is 30%) at 100° C. for 12 hours to perform nucleophilic substitution, and the phosphazene compound is obtained after centrifugal drying.

[0065] The modified glass powder is prepared by compounding glass powders with melting points of 350°C, 500°C, and 700°C in a mass ratio of 1:1:1 and then modifying with silane. The specific preparation process of the modified glass powder is as follows:

[0066] (1) Grinding glass powders with melting points of 350°C, 500°C, and 700°C in a mass ratio of 1:1:1, sieving and mixing, and ball milling for 30 minutes to obtain a composite glass powder;

[0067] (2) Dispersing 10 parts by mass of the composite glass powder in an ethanol / water solution to prepare an ethanol / water mixed solution (volume ratio of ethanol:water = 8:2, the mass concentration of the glass powder in the solution is 25%), then adding 2 parts by mass of silane coupling agent KH570, and mechanically stirring for 30 minutes to ensure that the glass powder is evenly mixed;

[0068] (3) The temperature of the modified system was kept constant at 60°C, the reaction was carried out for 12 hours, and the modified glass powder was obtained after freeze-drying.

[0069] The preparation process of environmentally friendly silicone intumescent fire retardant coating for substations or converter stations is as follows:

[0070] (1) Grinding an intumescent flame retardant, modified glass powder, and talc powder, sieving, and ball milling for 30 minutes to obtain a composite filler;

[0071] (2) preparing a 40% by mass SJ-804 epoxy modified silicone resin aqueous solution, adding the composite filler and polyester phosphate 5063A adhesion promoter prepared in step (1), and stirring at 50° C. for 60 min;

[0072] (3) Add polyurethane curing agent and stir for 30 minutes to obtain a uniformly mixed organic silicone intumescent fire retardant coating, which is then applied by brush. The substrate is stainless steel and the coating thickness is 3 mm.

[0073] Example 2

[0074] Disclosed is an environmentally friendly organic silicon intumescent fire retardant coating for use in substations or converter stations. The raw materials thereof include, by mass, 40 parts of SJ-804 epoxy-modified organic silicon resin, 35 parts of intumescent flame retardant, 8 parts of modified glass powder, 3 parts of talc, 4 parts of polyester phosphate 5063A adhesion promoter, and 10 parts of polyurethane curing agent.

[0075] Among them, the intumescent flame retardant is a phosphazene compound as a gas source and an acid source, ammonium polyphosphate as an acid source, and expanded graphite as a carbon source. The mass ratio of the phosphazene compound, ammonium polyphosphate and expanded graphite is 2:1:1.

[0076] The synthesis steps of the phosphazene compound are as follows: hexachlorocyclotriphosphazene and dicyandiamide (molar ratio of 1:3) are refluxed in a pyridine solution (the mass concentration of hexachlorocyclotriphosphazene in the pyridine solution is 30%) at 100°C for 12 hours for nucleophilic substitution. After centrifugal drying, the phosphazene compound is obtained, which serves as the gas source and acid source of the intumescent flame retardant.

[0077] The modified glass powder is prepared by compounding glass powders with melting points of 350°C, 500°C, and 700°C in a mass ratio of 1:1:1 and then modifying the glass powder with silane. The specific preparation process of the modified glass powder is as follows:

[0078] (1) Grinding glass powders with melting points of 350°C, 500°C, and 700°C in a mass ratio of 1:1:1, sieving and mixing, and ball milling for 30 minutes to obtain a composite glass powder;

[0079] (2) 10 parts by mass of the composite glass powder were weighed according to the proportion and dispersed in an ethanol / water solution (volume ratio of ethanol: water = 8:2, the mass concentration of the glass powder in the solution was 25%), 8 parts by mass of silane coupling agent KH-570 were added, refluxed at 60°C for 12 hours, and freeze-dried to obtain the modified glass powder.

[0080] The preparation process of environmentally friendly silicone intumescent fire retardant coating for substations or converter stations is as follows:

[0081] (1) Grinding an intumescent flame retardant, modified glass powder, and talc powder, sieving, and ball milling for 30 minutes to obtain a composite filler;

[0082] (2) preparing a 40% by mass SJ-804 epoxy modified silicone resin aqueous solution, adding the composite filler and polyester phosphate 5063A adhesion promoter prepared in step (1), and stirring at 50° C. for 60 min;

[0083] (3) Add polyurethane curing agent and stir for 30 minutes to obtain a uniformly mixed organic silicone intumescent fire retardant coating, which is then applied by brush. The substrate is stainless steel and the coating thickness is 3 mm.

[0084] Example 3

[0085] Disclosed is an environmentally friendly organic silicon intumescent fire retardant coating for use in substations or converter stations. The raw materials thereof include, by weight, 40 parts of SJ-804 epoxy-modified organic silicon resin, 45 parts of intumescent flame retardant, 5 parts of modified glass powder, 2 parts of talc, 2 parts of polyester phosphate 5063A adhesion promoter, and 6 parts of polyurethane curing agent.

[0086] Among them, the intumescent flame retardant is a phosphazene compound as a gas source and an acid source, ammonium polyphosphate as an acid source, and starch as a carbon source. The mass ratio of the phosphazene compound, ammonium polyphosphate and starch is 1:2:1.

[0087] Synthesis of phosphazene compounds: Hexachlorocyclotriphosphazene and melamine (molar ratio of 1:2) are refluxed in a pyridine solution (the mass concentration of hexachlorocyclotriphosphazene in the pyridine solution is 30%) at 100°C for 12 hours for nucleophilic substitution. After centrifugation and drying, the phosphazene compound is obtained, which serves as the gas source and acid source of the intumescent flame retardant.

[0088] The modified glass powder is glass powder with melting points of 350° C., 500° C., and 700° C. (mass ratio 1:1:1) and is modified with silane according to the method in Example 1.

[0089] The preparation process of environmentally friendly silicone intumescent fire retardant coating for substations or converter stations is as follows:

[0090] (1) Grinding an intumescent flame retardant, modified glass powder, and talc powder, sieving, and ball milling for 30 minutes to obtain a composite filler;

[0091] (2) preparing a 40% by mass fraction of an SJ-804 epoxy-modified silicone resin aqueous solution, adding the composite filler and polyester phosphate 5063A adhesion promoter prepared in step (1), and stirring at 50° C. for 60 min;

[0092] (3) Add polyurethane curing agent and stir for 30 minutes to obtain a uniformly mixed organic silicone intumescent fire retardant coating, which is then applied by brush. The substrate is stainless steel and the coating thickness is 4 mm.

[0093] Example 4

[0094] Disclosed is an environmentally friendly organic silicon intumescent fire retardant coating for use in substations or converter stations. The raw materials thereof include, by weight, 35 parts of SJ-804 epoxy-modified organic silicon resin, 45 parts of intumescent flame retardant, 5 parts of modified glass powder, 5 parts of nano-titanium dioxide, 2 parts of talc, 2 parts of polyester phosphate 5063A adhesion promoter, and 6 parts of polyurethane curing agent.

[0095] The intumescent flame retardant comprises a phosphazene compound as a gas source and an acid source, pentaerythritol as a carbon source, and the mass ratio of the phosphazene compound to the pentaerythritol is 4:1. The preparation process of the phosphazene compound is as described in Example 1.

[0096] The modified glass powder is glass powder with melting points of 350° C., 500° C., and 700° C. (mass ratio 1:1:1) and is modified with silane according to the method in Example 1.

[0097] The preparation process of environmentally friendly silicone intumescent fire retardant coating for substations or converter stations is as follows:

[0098] (1) Grinding an intumescent flame retardant, modified glass powder, nano titanium dioxide, and talc, sieving, and ball milling for 30 minutes to obtain a composite filler;

[0099] (2) preparing a 35% by mass fraction of an SJ-804 epoxy-modified silicone resin aqueous solution, adding the composite filler and polyester phosphate 5063A adhesion promoter prepared in step (1), and stirring at 50° C. for 60 min;

[0100] (3) Add polyurethane curing agent and stir for 30 minutes to obtain a uniformly mixed organic silicone intumescent fire retardant coating, which is then applied by brush. The substrate is stainless steel and the coating thickness is 4 mm.

[0101] Comparative Example 1

[0102] A silicone fire retardant coating, which differs from Example 1 only in that the mass ratio of each raw material is changed. The raw materials include 65 parts of SJ-804 epoxy modified silicone resin, 25 parts of intumescent flame retardant, 4 parts of modified glass powder, 2 parts of talcum powder, 4 parts of polyester phosphate 5063A adhesion promoter, and 15 parts of polyurethane curing agent in parts by mass.

[0103] The preparation process of the organic silicon fire retardant coating was the same as in Example 1, with the corresponding parameters changed. The substrate was stainless steel, and the coating thickness was 3 mm.

[0104] Comparative Example 2

[0105] A silicone fire retardant coating, which differs from Example 4 only in that the mass ratio of each raw material is changed: the raw materials include, in parts by mass, 25 parts of SJ-804 epoxy modified silicone resin, 50 parts of intumescent flame retardant, 12 parts of modified glass powder, 12 parts of nano titanium dioxide, 8 parts of talc, 10 parts of polyester phosphate 5063A adhesion promoter, and 5 parts of polyurethane curing agent; the rest are the same as Example 4.

[0106] The preparation process of the organic silicon fire retardant coating is as described in Example 4 above, with the corresponding parameters changed. The substrate is stainless steel and the coating thickness is 4 mm. The coating adhesion is very poor, the coating cracks and falls off, as shown in the following figure. Figure 8 shown.

[0107] Comparative Example 3

[0108] This comparative example is a silicone resin coating containing uncompounded glass powder. The only difference from Example 1 is that glass powder with a melting point of 350°C is used instead of the glass powders with melting points of 350°C, 500°C, and 700°C in Example 1. In the specific preparation process of the modified glass powder, the glass powder with a melting point of 350°C is ground, sieved, and ball-milled for 30 minutes. The remaining steps are the same as in Example 1.

[0109] Comparative Example 4

[0110] This comparative example is a silicone resin coating containing uncompounded glass powder. The only difference from Example 1 is that glass powder with a melting point of 500°C is used instead of the glass powders with melting points of 350°C, 500°C, and 700°C in Example 1. In the specific preparation process of the modified glass powder, the glass powder with a melting point of 500°C is ground, sieved, and ball-milled for 30 minutes. The remaining steps are the same as in Example 1.

[0111] Comparative Example 5

[0112] This comparative example is a silicone resin coating containing uncompounded glass powder. The only difference from Example 1 is that glass powder with a melting point of 700°C is used instead of the glass powders with melting points of 350°C, 500°C, and 700°C in Example 1. In the specific preparation process of the modified glass powder, the glass powder with a melting point of 700°C is ground, sieved, and ball-milled for 30 minutes. The remaining steps are the same as in Example 1.

[0113] Comparative Example 6

[0114] This comparative example presents a silicone resin coating with an intumescent flame retardant added alone. The only difference from Example 1 is the omission of modified glass frit. The raw materials, in parts by mass, include 40 parts of SJ-804 epoxy-modified silicone resin, 48 parts of intumescent flame retardant, 5 parts of talc, 4 parts of polyester phosphate 5063A adhesion promoter, and 10 parts of polyurethane curing agent. The remaining steps are the same as in Example 1.

[0115] Comparative Example 7

[0116] This comparative example involves a silicone resin coating with modified glass powder added alone. The only difference from Example 1 is that the raw materials, by weight, include 40 parts of SJ-804 epoxy-modified silicone resin, 48 parts of modified glass powder, 5 parts of talc, 4 parts of polyester phosphate 5063A adhesion promoter, and 10 parts of polyurethane curing agent. The remaining steps are the same as in Example 1.

[0117] The organic silicon intumescent fire retardant coatings obtained in Examples 1-4 were compared with the organic silicon coatings obtained in Comparative Examples 1-7. An acetylene burner was used to provide a stable fire source at 1200°C. The coatings were applied to a stainless steel substrate. A thermocouple was used to record the back surface temperature of the plate after burning the 11 coatings at 1200°C for 60 minutes. The relevant data obtained are shown in Tables 1 and Figure 5 and Figure 9 shown.

[0118] Table 1 Back surface temperature of eleven silicone flame retardant coatings

[0119]

[0120] Among them, in Comparative Example 2 in the table, since the paint fell off during the burning process, there was no stable temperature and carbon layer expansion multiple on the back side, which was expressed as / ; since the blank sample surface was not coated with paint, there was no carbon layer expansion multiple, and the carbon layer expansion multiple was expressed as / .

[0121] From Table 1 and Figure 7 It can be seen that the carbon layer of the silicone coating with the addition of an intumescent flame retardant and glass powder expands, and the backside temperature is significantly lower than that of the control. In the 300-500°C range, the intumescent flame retardant pyrolyzes to generate a large amount of gas, which acts as the carbon source to expand the carbon layer. The compounded glass powder melts at different temperatures to form a secondary film, repairing cracks caused by high-temperature filling of the silicone resin.

[0122] Figure 1 The infrared spectrum of the phosphazene compound of Example 1 shows that the infrared absorption of the P=N and PN bonds in the phosphazene compound is located at 1214 cm -1 and 870cm -1 Nearby, the stretching vibration peaks of CN and C=N of the triazine ring structure in the phosphazene compound are 1673 cm -1 and 1508cm -1 These infrared characteristics indicate that the phosphazene compound was successfully prepared.

[0123] Figure 2This is the XRD spectrum of the phosphazene compound of Example 1. It can be seen that compared with the raw materials melamine and hexachlorocyclotriphosphazene, the structural regularity and order of the phosphazene compound are reduced after the copolymerization reaction of melamine and hexachlorocyclotriphosphazene. The crystal diffraction of the phosphazene compound is located near 27°, indicating an amorphous crystalline state.

[0124] Figure 3 This is the thermogravimetric curve of the phosphazene compound of Example 1. The temperatures at which the phosphazene compound loses 5 wt% of its weight under nitrogen and air are 323.0°C and 351.0°C, respectively. The pyrolysis range is consistent with the gas source and acid source in the intumescent flame retardant system.

[0125] Figure 4 This is a scanning electron microscope image of the phosphazene compound of Example 1, from which it can be seen that the microscopic morphology of the phosphazene compound is solid particles of 1-2 μm.

[0126] Figure 5 Figure 2 shows the backside temperature curves of the silicone intumescent fire-retardant coatings prepared in Examples 1-4. The backside temperature curve represents the backside temperature at the center of the coating exposed to fire. The final stable center temperature maintained on the backside of the coatings in Examples 1-4 was below 300°C.

[0127] Figure 6 The following are digital images of the organic silicon intumescent fire retardant coating (left) and the char layer (right) prepared in Example 1. The coating surface is dense and crack-free, while the char layer appears white due to the presence of glass powder.

[0128] Figure 7 This is a scan of the expanded carbon layer of the organosilicon intumescent fire retardant coating prepared in Example 2. The carbon layer of the coating is expanded and porous.

[0129] Figure 8 This is a digital image of the fire retardant coating prepared in Comparative Example 2, and the coating surface is powdering.

[0130] Figure 9Figure 1 shows the backside temperature test results for the organosilicon intumescent flame-retardant fire-retardant coatings prepared in Comparative Examples 1-7. The blank sample shows the backside temperature of the uncoated substrate. The backside temperature results for Comparative Examples 1-7 are shown in Table 1. Due to the increased mass fraction of the organosilicon resin film-forming agent in Comparative Example 1, the mass fraction of the high-temperature resistant components (intumescent flame retardant and modified glass powder) in the coating is lower, resulting in poorer high-temperature resistance than in the examples. Due to the reduced mass fraction of the organosilicon film-forming agent in Comparative Example 2, the coating adhesion is reduced, and the coating falls off during the burning test. In Comparative Examples 3-5, the glass frit had a single melting point. When the glass frit melted at 350°C, it melted too quickly, causing meltthrough and cracking in the coating, reducing its high-temperature resistance. When the glass frit melted at 500°C, the initial temperature of its melt flow failed to cover the decomposition process of the intumescent flame retardant, leading to cracking in the coating. When the glass frit melted at 700°C, the temperature of its melt flow was too high to allow for secondary film formation after the decomposition of the silicone resin film-forming agent. Therefore, the heat resistance of the coatings containing single-melting-point glass frit was inferior to that of the composite glass frit. In Comparative Examples 6-7, when the intumescent flame retardant was added alone, the char layer of the coating expanded, resulting in superior high-temperature resistance, but fine cracking during burning. However, when the composite glass frit was added alone, the char layer of the coating expanded poorly, and the back-temperature insulation performance exceeded 300°C. Therefore, the combined action of the composite glass frit and intumescent flame retardant significantly improved the high-temperature resistance and heat insulation performance of the coating.

[0131] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. An environmentally friendly organic silicon intumescent fire retardant coating for a transformer substation or a converter station, characterized by: The raw materials include, by mass: 30-60 parts of epoxy modified silicone resin, 30-45 parts of intumescent flame retardant, 5-10 parts of modified glass powder, 2-20 parts of inorganic filler, 2-10 parts of auxiliary agent, and 5-25 parts of polyurethane curing agent; The intumescent flame retardant uses a phosphazene compound as a gas source and an acid source; the phosphazene compound is formed by a nucleophilic substitution reaction between hexachlorocyclotriphosphazene and melamine or dicyandiamide; The modified glass powder is prepared by mixing three kinds of glass powders with melting points of 350°C, 500°C and 700°C and then modifying them with a silane coupling agent.

2. The environmentally friendly organic silicon intumescent fire retardant coating for a transformer substation or converter station according to claim 1, characterized in that: The acid source of the intumescent flame retardant further comprises ammonium polyphosphate.

3. The environmentally friendly organic silicon intumescent fire retardant coating for a transformer substation or converter station according to claim 2, characterized in that: The mass ratio of ammonium polyphosphate to the phosphazene compound is 1-2:1-2.

4. The environmentally friendly organic silicon intumescent fire retardant coating for a transformer substation or converter station according to claim 1, characterized in that: The carbon source of the intumescent flame retardant is a mixture of one or more of pentaerythritol, dipentaerythritol, starch and expanded graphite.

5. The environmentally friendly organic silicon intumescent fire retardant coating for a transformer substation or converter station according to claim 1, characterized in that: The mass ratio of the phosphazene compound to the intumescent flame retardant carbon source is 1-4:

1.

6. The environmentally friendly organic silicon intumescent fire retardant coating for a transformer substation or converter station according to claim 1, characterized in that: The mass ratio of the three glass powders with melting points of 350°C, 500°C and 700°C is 1:1:

1.

7. The environmentally friendly organic silicon intumescent fire retardant coating for a transformer substation or converter station according to claim 1, characterized in that: The preparation process of the modified glass powder includes the following steps: grinding and sieving three types of glass powder with melting points of 350°C, 500°C and 700°C, mixing and ball milling, mixing with ethanol and water, adding a silane coupling agent, heating for reaction, and drying to obtain the modified glass powder.

8. The environmentally friendly organic silicon intumescent fire retardant coating for a transformer substation or converter station according to claim 7, characterized in that: The reaction temperature was 60°C and the reaction time was 12 h.

9. The environmentally friendly organic silicon intumescent fire retardant coating for a transformer substation or converter station according to claim 1, characterized in that: The silane coupling agent is an amino functional silane coupling agent.

10. The environmentally friendly organic silicon intumescent fire retardant coating for a transformer substation or converter station according to claim 1, characterized in that: The mass ratio of the silane coupling agent to the glass powder is 1:1-5.

11. The environmentally friendly organic silicon intumescent fire retardant coating for a transformer substation or converter station according to claim 1, characterized in that: The inorganic filler is a mixture of one or more of talc, Mxene, graphene, expanded graphite, vermiculite, Al2O3, and nano titanium dioxide.

12. The environmentally friendly organic silicon intumescent fire retardant coating for a transformer substation or converter station according to claim 1, characterized in that: The auxiliary agent is an adhesion promoter.

13. The environmentally friendly organic silicon intumescent fire retardant coating for a transformer substation or converter station according to claim 12, characterized in that: The adhesion promoter includes a mixture of one or more of polyester phosphate 5063A adhesion promoter, 5140B water-based adhesion promoter, and AKN-6618 adhesion promoter.

14. A method for preparing an environmentally friendly organic silicon intumescent fire retardant coating for a transformer substation or converter station according to any one of claims 1 to 13, characterized in that: The method comprises the following steps: mixing an inorganic filler, an intumescent flame retardant and a modified glass powder by ball milling to obtain a composite filler; preparing an epoxy-modified organic silicon resin aqueous solution, adding the composite filler and an auxiliary agent, heating and stirring, then adding a polyurethane curing agent and stirring to obtain the environmentally friendly organic silicon intumescent fire retardant coating for a transformer substation or a converter station.

15. The method for preparing the environmentally friendly organic silicon intumescent fire retardant coating for a transformer substation or a converter station according to claim 14, characterized in that: The mass concentration of the epoxy-modified silicone resin aqueous solution is 30-50%.

16. The method for preparing the environmentally friendly organic silicon intumescent fire retardant coating for transformer substations or converter stations according to claim 14 or 15, characterized in that: Heat to 50°C and stir for 60 minutes, then add the polyurethane curing agent.

17. A coating, characterized in that: The invention is prepared by using the environmentally friendly organic silicon intumescent fire retardant coating for a transformer substation or a converter station according to any one of claims 1 to 13.

18. Use of the environmentally friendly organic silicon intumescent fire retardant coating for a transformer substation or a converter station according to any one of claims 1 to 13 in a transformer substation or a converter station.

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