Rail transit vehicle roof arc-resistant coating and preparation method thereof

Abstract

The application discloses a rail transit vehicle roof arc-resistant coating, which comprises 2 parts of A component and 1 part of B component by weight; the A component comprises 10-50 parts of polyol, 10-50 parts of MQ silicone resin, 10-30 parts of flame retardant, 5-10 parts of thixotropic agent, 0.3-2 parts of adhesion promoter and 0.1-1 part of catalyst by mass fraction; the B component is hexamethylene diisocyanate or isofluorane diisocyanate; the functional structure of the MQ silicone resin is (R3SiO 1 / 2 )m(SiO 4 / 2 )n, wherein R is methyl, vinyl, hydrogen or phenyl, and the molecular weight of the MQ silicone resin is 1500-3000, and m / n=0.8. The application further discloses a preparation method of the rail transit vehicle roof arc-resistant coating. The rail transit vehicle roof arc-resistant coating provided by the application realizes the formation of effective thickness on a vertical surface or a top surface by means of blade coating without problems such as sagging, guarantees the insulation and arc-resistant performance of the arc-resistant coating after solidification, and effectively improves the construction performance of the arc-resistant coating on the vertical surface and the top surface.

Description

Technical Field

[0001] This invention belongs to the technical field of rail transit coating materials, specifically relating to an anti-arc coating for the roof of a rail transit vehicle and its preparation method. Background Technology

[0002] With the expansion of China's railway network and the booming development of urban rail transit, the demand for electric locomotives (including subway and high-speed trains) has experienced rapid growth. During this process, research on improving the safety performance of existing electric locomotives has deepened. In operation, existing electric locomotives draw power from the overhead contact line through electrical equipment mounted on the locomotive roof. The load current is transmitted to the locomotive's electric traction system through the contact wire of the contact line and the pantograph of the locomotive's electrical equipment. In this process, parameters such as the contact pressure, transition resistance, and contact area between the contact wire and the pantograph determine the smoothness of current transmission and its safety. The high-voltage electricity in the contact line forms a grounding loop through the discharge point, resulting in a large short-circuit current, typically exceeding 2000A. Simultaneously, the instantaneous high current in the contact line can cause the substation protection system to trip, leading to a power outage in the contact line. When two or more flashovers occur simultaneously on the roof of a locomotive, the current will rise sharply, reaching up to 4000A or more, and extremely high temperatures will be generated between the pantograph and the overhead contact line. If the locomotive is stopped at this time, the large current will be concentrated on one point of the contact line, which will burn out the contact line. This is especially true when the locomotive is stopped on a siding at a station (the siding line is generally thinner and has lower strength than the main line line), which can easily lead to a C14 type accident of burning out the contact line.

[0003] To address this issue, existing technologies propose coating the locomotive roof with an anti-arc coating to handle similar faults. For example, patent documents CN108084868B and CN112029393B disclose an anti-arc insulating coating for the locomotive roof comprising two components, A and B, and its preparation method. Component A is a mixture of polyols and various fillers, while component B is at least one of diphenylmethane diisocyanate and polymethylene polyphenyl polyisocyanate. However, in these patented solutions, the polyisocyanates containing aromatic rings, represented by diphenylmethane diisocyanate and polymethylene polyphenyl polyisocyanate, are susceptible to significant degradation in color and mechanical properties outdoors, especially in areas with strong ultraviolet radiation, due to their internal molecular structure (the aromatic rings form conjugated π bonds with the isocyanate, making them relatively easy to oxidize and form colored quinone structures). Furthermore, their insulation performance cannot meet the requirements of a single maintenance cycle (10-12 years) for railway locomotives.

[0004] In addition, existing anti-arc coatings, which use polyurethane as the main base material, often require multiple layers of application during construction to further improve their aging resistance. This includes adding a topcoat layer and other materials to provide UV protection for the polyurethane material, which is inefficient and unsuitable for scenarios with strict regulations on locomotive parking time windows, such as locomotive preparation and maintenance. Summary of the Invention

[0005] This invention aims to at least partially solve one of the technical problems in related technologies. Therefore, the main objective of this invention is to provide an anti-arc coating for the roof of a rail transit vehicle that simultaneously possesses environmental friendliness, excellent flame retardant properties, electrical properties, and weather resistance; this invention also provides a method for preparing this anti-arc coating for the roof of a rail transit vehicle.

[0006] The objective of this invention is achieved through the following technical solution:

[0007] An anti-arc coating for the roof of a rail transit vehicle, comprising, by weight, 2 parts of component A and 1 part of component B; by weight, component A comprises 10-50 parts of polyol, 10-50 parts of reinforcing MQ silicone resin, 10-30 parts of flame retardant, 5-10 parts of thixotropic agent, 0.3-2 parts of adhesion promoter, and 0.1-1 part of catalyst; component B is hexamethylene diisocyanate or isochlorophenone diisocyanate; the functional structure of the MQ silicone resin is: (R3SiO 1 / 2 )m(SiO 4 / 2 )n, where R is methyl, vinyl, hydrogen, or phenyl, and the molecular weight of MQ silicone resin is 1500-3000, m / n = 0.8.

[0008] In some specific embodiments, the flame retardant includes one or more of aluminum hydroxide, magnesium hydroxide, DOPO, DOPO-HQ, DOPO-DDP, or hexaphenoxycyclotriphosphazene.

[0009] In some specific embodiments, the thixotropic agent is a mixture of organobentonite, asbestos fiber, mica powder, and attapulgite.

[0010] Furthermore, the mass ratio of the organic bentonite, asbestos fiber, mica powder and attapulgite is 2:(1-3):(1-3):(2-4).

[0011] In some specific embodiments, the catalyst comprises one or more of dibutyltin disilicate, stannous octoate, and triethylenediamine.

[0012] In some specific embodiments, the polyol includes polyester polyol and polyether polyol, wherein the relative molecular mass of the polyol is 300-2000 and the hydroxyl value is 20-500 mgKOH / g.

[0013] In some specific embodiments, the adhesion promoter is a modified epoxy silane coupling agent.

[0014] A method for preparing the aforementioned anti-arc coating on the roof of a rail transit vehicle includes the following steps:

[0015] Preparation of component A: In a double planetary mixer, polyol and MQ silicone resin are added according to the mass fraction and mixed evenly. Then, flame retardant, thixotropic agent, adhesion promoter and catalyst are added in sequence. The speed is adjusted to 80-120 rpm and heated to 80-120℃. Vacuum is turned on to remove bubbles and small molecules. The mixture is maintained at 80-120 rpm for 1.5-2 hours to ensure that the materials are mixed evenly. Then, the mixture is cooled and discharged to obtain component A.

[0016] Preparation of component B: Take hexamethylene diisocyanate or isoflurane diisocyanate, mix them evenly to obtain component B;

[0017] Material usage: Mix components A and B evenly at a mass ratio of 2:1, and apply the mixture to the top and / or vertical surfaces of the railway locomotive using a scraper.

[0018] Compared with the prior art, the present invention has at least the following advantages:

[0019] 1) The anti-arc coating for the roof of rail transit vehicles provided by this invention incorporates MQ silicone resin. MQ silicone resin has excellent weather resistance, and its physical properties remain relatively stable under different climatic conditions, without melting or decomposition. Meanwhile, this application selects aliphatic isocyanate as component B, which is not only tough and wear-resistant, and resistant to chemical corrosion, but also flexible, easily adhering to various substrates, and possesses excellent durability and flexibility. By incorporating MQ silicone resin and selecting aliphatic isocyanate with excellent weather resistance as a curing agent, the two work synergistically to give the anti-arc coating for the roof of rail transit vehicles in this application excellent weather resistance and aging resistance, thereby greatly improving its long-term anti-arc properties and insulation.

[0020] 2) For traditional polyurethane materials, in order to further improve their aging resistance, multiple layers of application are often required during construction, including topcoat layers, to provide UV protection. The anti-arc coating for the roof of rail transit vehicles provided in this application reduces the traditional three-layer application standard of polyurethane materials to a single layer, greatly improving work efficiency, reducing labor costs, and providing construction possibilities for scenarios with strict regulations on locomotive parking time windows, such as locomotive preparation and construction.

[0021] 3) The anti-arc coating for the roof of rail transit vehicles provided in this application uses a mixture of organic bentonite, asbestos fiber, mica powder and attapulgite as a thixotropic agent. Through the synergistic effect of the various raw material components with different structural configurations, such as organic bentonite with a lamellar structure, fibrous asbestos fiber, rod-shaped, fibrous and needle-shaped crystals with a layered structure, and mica powder with a layered structure, the anti-arc coating has excellent consistency and viscosity. It can form an effective thickness on the vertical or top surface by scraping without problems such as sagging. It ensures the insulation and anti-arc performance of the anti-arc coating after curing and effectively improves the construction performance of the anti-arc coating on the vertical and top surfaces.

[0022] 4) The method for preparing the anti-arc coating on the roof of rail transit vehicles provided by this invention uses readily available raw materials, is environmentally friendly, has simple process steps, high repeatability and stability, and is suitable for industrial application. Detailed Implementation

[0023] The present invention will be further described in detail below with reference to specific embodiments. The following embodiments are merely descriptive and not limiting, and should not be used to limit the scope of protection of the present invention.

[0024] When a quantity, concentration, or other value or parameter is described as a range, preferred range, or preferred upper and lower limits, it should be understood that it is equivalent to specifically disclosing any range by combining any pair of upper or preferred values ​​with any lower or preferred values, regardless of whether the range is specifically disclosed. Unless otherwise stated, the numerical range values ​​listed herein include the endpoints of the range and all integers and fractions within that range.

[0025] Unless otherwise stated, all percentages, parts, ratios, etc. in this document are by weight.

[0026] The materials, methods, and embodiments described herein are exemplary and should not be construed as limiting unless otherwise stated.

[0027] An anti-arc coating for the roof of a rail transit vehicle, comprising, by weight, 2 parts of component A and 1 part of component B; by weight, component A comprises 10-50 parts of polyol, 10-50 parts of reinforcing MQ silicone resin, 10-30 parts of flame retardant, 5-10 parts of thixotropic agent, 0.3-2 parts of adhesion promoter, and 0.1-1 part of catalyst; component B is hexamethylene diisocyanate or isochlorophenone diisocyanate; the functional structure of the MQ silicone resin is: (R3SiO 1 / 2 )m(SiO 4 / 2)n, where R is methyl, vinyl, hydrogen, or phenyl, and the molecular weight of MQ silicone resin is 1500-3000, m / n = 0.8; in the following examples, the molecular weight of MQ silicone resin is 1800, m / n = 0.8.

[0028] In some specific embodiments, the flame retardant includes one or more of aluminum hydroxide, magnesium hydroxide, DOPO, DOPO-HQ, DOPO-DDP, or hexaphenoxycyclotriphosphazene.

[0029] In some specific embodiments, the thixotropic agent is a mixture of organobentonite, asbestos fiber, mica powder, and attapulgite.

[0030] In the following embodiments, the organic bentonite (mesh size 180 mesh) is an inorganic mineral / organic ammonium composite material. It is made by inserting an organic covering agent through ion exchange technology, utilizing the lamellar structure of montmorillonite in bentonite and its ability to swell and disperse into colloidal particles in water or organic solvents.

[0031] Asbestos fiber (500 mesh) is a natural fibrous silica mineral fiber;

[0032] Attapulgite is a hydrous magnesium-aluminate silicate rare clay mineral with a layered chain structure. Its crystal form is rod-shaped, needle-shaped, or fibrous, with a length of 0.5-5 micrometers (μm) and a width of 0.05-0.15 micrometers (μm). It is a 2:1 type clay mineral, that is, two layers of silicon-oxygen tetrahedra and one layer of aluminum-oxygen octahedra. It appears as a grayish-white or bluish-gray powder with a greasy luster. It is odorless and tasteless. Each gram of attapulgite can produce more than 350 m². It is chemically stable and was purchased from Gansu Rongwan Technology Co., Ltd.

[0033] Mica powder is a layered silicate with a complex silicon-oxygen layer consisting of two silicon-oxygen tetrahedra sandwiching a layer of aluminum-oxygen octahedra. The particle size of mica powder is 400 mesh.

[0034] The organic bentonite, asbestos fiber, mica powder and attapulgite used in this application can all be purchased commercially, and other raw materials not specifically mentioned in this application can also be purchased commercially.

[0035] In some specific embodiments, the catalyst comprises one or more of dibutyltin disilicate, stannous octoate, and triethylenediamine.

[0036] In some specific embodiments, the polyol includes polyester polyol and polyether polyol, wherein the relative molecular mass of the polyol is 300-2000 and the hydroxyl value is 20-500 mgKOH / g.

[0037] In some specific embodiments, the adhesion promoter is a modified epoxy silane coupling agent; in the following examples, the modified epoxy silane coupling agent is A-187 (3-(2,3-epoxypropoxy)propyltrimethoxysilane).

[0038] A method for preparing the aforementioned anti-arc coating on the roof of a rail transit vehicle includes the following steps:

[0039] Preparation of component A: In a double planetary stirred tank, polyol and MQ silicone resin are added according to the mass parts and mixed evenly. Then, flame retardant, thixotropic agent, adhesion promoter and catalyst are added in sequence. The speed is adjusted to 80-120 rpm and heated to 80-120℃. Vacuum is turned on to remove bubbles and small molecules. The mixture is maintained at 80-120 rpm for 1.5-2 hours to make the material evenly mixed. Then, the material is cooled and discharged to obtain component A.

[0040] Preparation of component B: Take hexamethylene diisocyanate or isoflurane diisocyanate, mix them evenly to obtain component B;

[0041] Material usage: Mix components A and B evenly at a mass ratio of 2:1, and apply the mixture to the top and / or vertical surfaces of the railway locomotive using a scraper.

[0042] Example 1

[0043] The method for preparing the anti-arc coating on the roof of a rail transit vehicle provided by the present invention includes the following steps:

[0044] Preparation of component A: In a double planetary stirred tank, add 25 parts of polyol and 15 parts of MQ silicone resin by weight and mix evenly. Then add 10 parts of flame retardant, 10 parts of thixotropic agent, 0.8 parts of adhesive accelerator and 0.6 parts of catalyst in sequence. Adjust the speed to 100 rpm and heat to 120°C. Then turn on the vacuum to remove bubbles and small molecules. Maintain the speed at 100 rpm for 1.5 hours to make the material mix evenly. Then cool down and discharge to obtain component A.

[0045] Preparation of component B: Component B is isoflurone diisocyanate;

[0046] Material usage: Mix components A and B evenly at a mass ratio of 1:1, and apply the mixture to the top and vertical surfaces of the railway locomotive using a scraper.

[0047] The functional structure of the MQ silicone resin is: (R3SiO) 1 / 2 )m(SiO 4 / 2The composition is as follows: R is phenyl (molecular weight 1800m / n = 0.8); the flame retardant is aluminum hydroxide and magnesium hydroxide in a mass ratio of 2:1; the thixotropic agent is a mixture of organobentonite, asbestos fiber, mica powder and attapulgite in a mass ratio of 2:2:1:3; the catalyst is dibutyltin disilicate; the polyol is a polyester polyol with a relative molecular mass of 1800 and a hydroxyl value of 300 mgKOH / g; the adhesion promoter is a modified epoxy silane coupling agent.

[0048] Example 2

[0049] The method for preparing the anti-arc coating on the roof of a rail transit vehicle provided by the present invention includes the following steps:

[0050] Preparation of component A: In a double planetary stirred tank, add 40 parts of polyol and 10 parts of MQ silicone resin by weight and mix evenly. Then add 20 parts of flame retardant, 6 parts of thixotropic agent, 1 part of adhesive accelerator and 0.6 parts of catalyst in sequence. Adjust the speed to 120 rpm and heat to 80°C. Then turn on the vacuum to remove bubbles and small molecules. Maintain the speed at 120 rpm for 1.5 hours to make the material mix evenly. Then cool down and discharge to obtain component A.

[0051] Preparation of component B: Component B is isoflurone diisocyanate;

[0052] Material usage: Mix components A and B evenly at a mass ratio of 2:1, and apply the mixture to the top and vertical surfaces of the railway locomotive using a scraper.

[0053] The functional structure of the MQ silicone resin is: (R3SiO) 1 / 2 )m(SiO 4 / 2 The composition is as follows: R is vinyl (molecular weight 1800m / n = 0.8); the flame retardant is hexaphenoxycyclotriphosphazene; the thixotropic agent is a mixture of organobentonite, asbestos fiber, mica powder and attapulgite in a mass ratio of 2:1:3:2; the catalyst is stannous octoate; the polyol is a polyether polyol with a relative molecular mass of 1000 and a hydroxyl value of 200 mgKOH / g; the adhesion promoter is a modified epoxy silane coupling agent.

[0054] Example 3

[0055] The method for preparing the anti-arc coating on the roof of a rail transit vehicle provided by the present invention includes the following steps:

[0056] Preparation of component A: In a double planetary stirred tank, add 50 parts of polyol and 5 parts of MQ silicone resin by weight and mix evenly. Then add 30 parts of flame retardant, 5 parts of thixotropic agent, 1.5 parts of adhesive accelerator and 0.6 parts of catalyst in sequence. Adjust the speed to 100 rpm and heat to 105℃. Then turn on the vacuum to remove bubbles and small molecules. Maintain the speed at 100 rpm for 1.5 hours to make the material mix evenly. Then cool down and discharge to obtain component A.

[0057] Preparation of component B: Component B is hexamethylene diisocyanate;

[0058] Material usage: Mix components A and B evenly at a mass ratio of 2:1, and apply the mixture to the top and vertical surfaces of the railway locomotive using a scraper.

[0059] The functional structure of the MQ silicone resin is: (R3SiO) 1 / 2 )m(SiO 4 / 2 The composition is as follows: R is methyl (molecular weight 1800m / n = 0.8); the flame retardant is magnesium hydroxide; the thixotropic agent is a mixture of organobentonite, asbestos fiber, mica powder and attapulgite in a mass ratio of 2:3:2:2; the catalyst includes dibutyltin disilicate; the polyol includes polyester polyol, the polyester polyol having a relative molecular mass of 600 and a hydroxyl value of 100 mgKOH / g; the adhesion promoter is a modified epoxy silane coupling agent.

[0060] Comparative Example 1

[0061] The method for preparing an anti-arc coating on the roof of a rail transit vehicle provided in this comparative example has the same components and proportions as in Example 2, except that MQ silicone resin is not added; the process steps are the same as in Example 2.

[0062] Comparative Example 2

[0063] The method for preparing an anti-arc coating on the roof of a rail transit vehicle provided in this comparative example has the same components and proportions as in Example 2, except that diphenylmethane diisocyanate is used as component B; the process steps are the same as in Example 2.

[0064] Comparative Example 3

[0065] The method for preparing an anti-arc coating on the roof of a rail transit vehicle provided in this comparative example has the same components and proportions as in Example 2, except that no organic bentonite is added; the process steps are the same as in Example 2.

[0066] Comparative Example 4

[0067] The method for preparing an anti-arc coating on the roof of a rail transit vehicle provided in this comparative example has the same components and proportions as in Example 2, except that asbestos fibers are not added; the process steps are the same as in Example 2.

[0068] Comparative Example 5

[0069] The preparation method of the anti-arc coating on the roof of a rail transit vehicle provided in this comparative example has the same components and proportions as in Example 2, except that mica powder is not added; the process steps are the same as in Example 2.

[0070] Comparative Example 6

[0071] The method for preparing an anti-arc coating on the roof of a rail transit vehicle provided in this comparative example has the same components and proportions as in Example 2, except that attapulgite is not added; the process steps are the same as in Example 2.

[0072] This application presents performance tests on the anti-arc coatings prepared in Examples 1-3 and Comparative Examples 1-6:

[0073] 1) Weather resistance test:

[0074] This application tested the weather resistance of the arc-resistant coatings prepared in Examples 1-3 and Comparative Examples 1-6 using a method of accelerated aging (GB / T 14522-2008) followed by an arc resistance test (GB / T6553-2014). The results are shown in Table 1.

[0075] Table 1. Weather resistance of the anti-arc coating in each embodiment and comparative example.

[0076]

[0077] As shown in Table 1, the anti-arc coatings for the roofs of rail transit vehicles provided in this application all exhibit excellent aging resistance and anti-arc properties. The addition of MQ silicone resin significantly improves the aging resistance and anti-arc properties of the anti-arc coating. When diphenylmethane diisocyanate is used as component B, the anti-arc coating prepared by using diphenylmethane diisocyanate, which is an isocyanate containing an aromatic ring, suffers from severe yellowing, discoloration, and aging, failing to meet the requirements for use. Furthermore, as shown in Comparative Examples 5 and 6, the addition of mica powder and attapulgite to the coating system can also effectively improve the aging resistance of the anti-arc coating.

[0078] In addition, this application also selected similar products currently available in the domestic and Japanese (imported) markets and conducted comparative tests with the anti-arc coating prepared in this application. The results are shown in Table 2:

[0079] Table 2 Performance comparison between Example 2 and similar products

[0080]

[0081]

[0082] As shown in Table 2, the anti-arc coating for the roof of rail transit vehicles provided in this application has better overall performance compared with similar products on the market.

[0083] 2) Construction performance test

[0084] The application tests the construction performance of the anti-arc coatings for the roofs of rail transit vehicles prepared in Examples 1-3 and Comparative Examples 3-6 of this application. This example uses a 2mm thick anti-arc coating as an example. The test method is as follows: after applying a 2mm thick layer of material to a vertical surface, the surface is left upright until the material cures. The downward flow, appearance, and Ti value of the coating are observed. The results are shown in Table 3.

[0085] Table 3. Construction performance tests of anti-arc coatings in each embodiment and comparative example.

[0086] Ti value Final thickness Flowing Number of constructions Apparent Example 1 7.6 3mm none 1 Smooth Example 2 8.1 3mm none 1 Smooth Example 3 8.9 4mm none 1 Smooth Comparative Example 1 9.0 4mm none 1 Smooth Comparative Example 2 8.1 3mm none 1 Smooth Comparative Example 3 3.4 0.5mm Flowing 1 Severe sagging Comparative Example 4 4.3 1mm Flowing 1 Flowing Comparative Example 5 5.6 1.5mm Flowing 1 Flowing Comparative Example 6 6.1 1 Flowing 1 Flowing

[0087] As can be seen from the data in Table 3, the anti-arc coating for the roof of rail transit vehicles provided in this application has excellent consistency and viscosity, enabling the formation of an effective thickness on the vertical or top surface of the vehicle roof through a scraping method without sagging. This results in a uniform thickness on the vertical or top surface of the vehicle roof, and the coating is free of pores and pinholes, ensuring the quality of the coating and greatly improving construction efficiency. Furthermore, due to the excellent weather resistance of this anti-arc coating, there is no need for intermediate and topcoat coatings, significantly reducing the number of coats and improving construction efficiency. A comparison of Example 2 with Comparative Examples 3, 4, 5, and 6 shows that the thixotropic agent composed of organic bentonite, asbestos fiber, mica powder, and attapulgite works synergistically to give the anti-arc coating a specific consistency and viscosity, thus enabling the formation of a uniformly thick anti-arc coating on the vertical or top surface of the vehicle roof in a single application, greatly improving construction efficiency while ensuring construction quality.

[0088] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be covered within the scope of the claims and specification of the present invention.

Claims

1. An anti-arc coating for the roof of a rail transit vehicle, characterized in that, By weight, it comprises 2 parts of component A and 1 part of component B; by mass, component A comprises 10-50 parts of polyol, 10-50 parts of MQ silicone resin, 10-30 parts of flame retardant, 5-10 parts of thixotropic agent, 0.3-2 parts of adhesion promoter, and 0.1-1 part of catalyst; component B is hexamethylene diisocyanate or isofluorine diisocyanate; the functional structure of the MQ silicone resin is: (R3SiO 1 / 2 )m(SiO 4 / 2 )n, where R is methyl, vinyl, hydrogen, or phenyl, and the molecular weight of MQ silicone resin is 1500-3000, m / n = 0.8; wherein the thixotropic agent is a mixture of organobentonite, asbestos fiber, mica powder, and attapulgite in a mass ratio of 2:(1-3):(1-3):(2-4).

2. The anti-arc coating for the roof of a rail transit vehicle according to claim 1, characterized in that, The flame retardant includes one or more of aluminum hydroxide, magnesium hydroxide, DOPO, DOPO-HQ, DOPO-DDP or hexaphenoxycyclotriphosphazene.

3. The anti-arc coating for the roof of a rail transit vehicle according to claim 1, characterized in that, The catalyst includes one or more of dibutyltin disilicate, stannous octoate, and triethylenediamine.

4. The anti-arc coating for the roof of a rail transit vehicle according to claim 1, characterized in that, The polyols include polyester polyols and polyether polyols, and the relative molecular mass of the polyols is 300-2000, and the hydroxyl value is 20-500 mgKOH / g.

5. The anti-arc coating for the roof of a rail transit vehicle according to claim 4, characterized in that, The adhesion promoter is a modified epoxy silane coupling agent.

6. A method for preparing an anti-arc coating on the roof of a rail transit vehicle according to any one of claims 1-5, characterized in that, Includes the following steps: Preparation of component A: In a double planetary stirred tank, polyol and MQ silicone resin are added according to the mass parts and mixed evenly. Then, flame retardant, thixotropic agent, adhesion promoter and catalyst are added in sequence. The speed is adjusted to 80-120 rpm and heated to 80-120℃. Vacuum is turned on to remove bubbles and small molecules. The mixture is maintained at 80-120 rpm for 1.5-2 hours to make the material evenly mixed. Then, the material is cooled and discharged to obtain component A. Preparation of component B: Take hexamethylene diisocyanate or isoflurane diisocyanate, mix them evenly to obtain component B; Material usage: Mix components A and B evenly at a mass ratio of 2:1, and apply the mixture to the top and / or vertical surfaces of the railway locomotive using a scraper.

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