Arc breakdown resistant insulating coating and its preparation method and application

Abstract

The present invention discloses an arc-breakdown-resistant insulating coating, a preparation method thereof, and an application thereof. The arc-breakdown-resistant insulating coating comprises a first component and a second component, wherein the first component comprises a dimer acid-modified epoxy resin, a silicon-modified epoxy resin, a leveling agent, a dispersant, and a flame retardant, etc.; and the second component comprises an amine resin, a modification aid, and a catalyst, etc. The arc-breakdown-resistant insulating coating of the present invention has good electrical strength, resistivity, elongation at break, and tensile strength. At the same time, it also has the tolerance and protection properties required for vehicles to operate in complex environments, such as excellent flame retardancy, water resistance, thermal conductivity, and corrosion resistance, etc., and is particularly suitable for parts such as the pantograph platform on the roof of rail transit vehicles.

Description

Technical Field

[0001] The present invention relates to an insulating coating, in particular to an arc breakdown resistant insulating coating and its preparation method and application, such as its application in manufacturing a protective structure for a pantograph platform on a rail transit vehicle roof, belonging to the technical field of functional coatings. Background Art

[0002] Currently, arcing in the pantograph and catenary systems is a bottleneck hindering the rapid development of my country's high-speed railways. Applying arc-resistant insulating coatings to the pantograph platform on the roof can significantly improve the pantograph's resistance to arc breakdown and ablation. However, ordinary insulating coatings release heat when exposed to high-voltage arcs. Excessively high temperatures can cause spontaneous combustion and lead to accidents. Therefore, an insulating coating with excellent flame retardancy and thermal conductivity is needed to effectively prevent these accidents.

[0003] Existing protective paints used on pantographs and roof bases generally prioritize corrosion protection over electrical insulation performance. This makes it difficult to simultaneously balance key performance indicators such as electrical performance, mechanical properties, flame retardancy, and thermal conductivity. However, as mentioned above, the electrical insulation performance of pantograph protective paint can directly impact vehicle safety. Therefore, existing insulating coatings used on pantograph platforms on rail transit vehicles pose a significant safety risk. Summary of the Invention

[0004] The main purpose of the present invention is to provide an arc-breakdown-resistant insulating coating, a preparation method and application thereof, so as to overcome the deficiencies in the prior art.

[0005] To achieve the aforementioned object of the invention, the technical solutions adopted by the present invention include:

[0006] A first aspect of an embodiment of the present invention provides an arc breakdown resistant insulating coating, comprising:

[0007] The first component comprises the following components calculated by weight:

[0008]

[0009]

[0010] The second component comprises the following components calculated by weight:

[0011]

[0012] In one embodiment, the silicon-modified epoxy resin includes but is not limited to any one of benzylaminopropyltrimethoxysilane-modified dimer acid-modified epoxy resin and benzylaminopropyltriethoxysilane-modified dimer acid-modified epoxy resin, or a combination of both.

[0013] In one embodiment, the flame retardant includes but is not limited to any one or more combinations of phosphate flame retardants, melamine, dicyandiamide, melamine salts, triazine nitrogen flame retardants, and polysiloxane flame retardants.

[0014] In one embodiment, the rheological additive includes but is not limited to a combination of any one or more of polyethylene wax, fumed silica, hydrogenated castor oil, polyurethane, bentonite, and polyamide wax.

[0015] In one embodiment, the dispersant includes but is not limited to any one or more combinations of alkyl ammonium salts containing high molecular weight copolymers, high polarity linear polymers, and modified polyurethane polymers.

[0016] In one embodiment, the functional filler includes but is not limited to a combination of any one or more of ceramic silicon powder, talc powder, silicon carbide, boron nitride, mica powder, aluminum hydroxide, and magnesium hydroxide.

[0017] In one embodiment, the pigments and fillers include anti-rust pigments and fillers, such as but not limited to any one or more combinations of titanium dioxide and other small amounts of pigments and fillers (such as rust red, chrome black, etc.).

[0018] In one embodiment, the defoaming agent includes but is not limited to any one or more combinations of organosilicon defoaming agents and organosilicon modified defoaming agents.

[0019] In one embodiment, the solvent includes but is not limited to any one or more combinations of benzene solvents (such as xylene), n-butanol, butanone, and BYKOK. Preferably, the solvent in the first component can be 1-3 parts.

[0020] In one embodiment, the amine resin includes but is not limited to a combination of any one or more of a polyetheramine curing agent and a polyamide adduct curing agent.

[0021] In one embodiment, the first catalyst includes but is not limited to any one or more combinations of tertiary amine catalysts, phenol catalysts (such as 2,4,6-tris(dimethylaminomethyl)phenol), and cross-linking catalysts.

[0022] In one embodiment, the modification aid includes a small molecule silane, for example, any one or more combinations of γ-glycidoxytrimethoxysilane and β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, but is not limited thereto.

[0023] In one embodiment, the mass ratio of the first component to the second component is 4-6:1.

[0024] The silicon-modified epoxy resin used in the arc-breakdown-resistant insulating coating of the present invention is formed by modifying a dimer acid-modified epoxy resin modified with benzylaminopropyltrimethoxysilane or benzylaminopropyltriethoxysilane. On the one hand, the organic silicon modification can enhance the electrical insulation performance of the resin itself under high temperature and humid conditions, so the electrical properties of the silicone resin at high temperature are slightly reduced. Although the resistivity of the silicon-modified resin will also decrease with increasing temperature, the reduction is much smaller than the reduction in the resistivity of the unmodified organic resin with increasing temperature. Under the conditions of the high-voltage arc of the pantograph, it still maintains good insulation. On the other hand, the organic silicon modification can improve the problem of poor miscibility between the organic silicon resin and the epoxy resin, and at the same time improve the wetting and penetration properties of the resin and the functional filler, improve the dispersion performance of the low-polarity filler, improve the thermal stability of the coating, prevent it from flocculating, and improve the coating. On the other hand, due to the large difference in polarity between the dimer acid modified epoxy resin and the amine curing agent, under normal circumstances, it is not easy to mix the two evenly due to the large viscosity, which can easily cause phase separation, affect the curing rate, and lead to uneven components of the coating system, which greatly affects the electrical properties. By adding a small amount of silicon-modified epoxy resin to the second component, the polarity of the amine curing agent can be changed, thereby greatly improving the compatibility of the first component and the second component, so that the various components in the coating can be better mixed evenly, thereby improving the uniformity of the coating cross-linking process, increasing the coating cross-linking density, and thus improving the coating's actual drying speed, long-term resistance and insulation properties.

[0025] It is particularly important to note that in the arc-resistant insulation coating of the present invention, by simultaneously using dimer acid-modified epoxy resin, silicon-modified epoxy resin, dispersant, functional filler, and modified amine resin, which work synergistically with each other and cooperate with the remaining components in the coating, the arc-resistant coating formed by the coating can greatly improve the arc-resistant and ablation-resistant performance of the pantograph when applied to the roof pantograph platform. It also has good thermal conductivity and flame retardant properties, and can prevent excessive temperature and avoid accidents caused by spontaneous combustion when it comes into contact with high-voltage arcs to generate heat. At the same time, the arc-resistant coating also has excellent mechanical properties such as elongation at break and tensile strength, as well as excellent environmental tolerance and protective performance, and can meet the balance of multiple key indicators such as electrical properties, mechanical properties, flame retardancy and thermal conductivity. In addition, the arc-resistant coating has good adhesion to the upper and lower coating systems.

[0026] A second aspect of an embodiment of the present invention provides a method for preparing the arc breakdown resistant insulating coating, comprising:

[0027] preparing raw materials according to the composition of the arc breakdown resistant insulating coating;

[0028] reacting the dimer acid-modified epoxy resin with benzylaminopropyltrimethoxysilane or benzylaminopropyltriethoxysilane in the presence of a second catalyst to prepare a silicon-modified epoxy resin;

[0029] uniformly mixing the silicon-modified epoxy resin with a dimer acid-modified epoxy resin, a rheological additive, a dispersant, a defoamer, a flame retardant, a pigment, a functional filler, and a solvent, which may or may not be added, to obtain a first component;

[0030] Evenly mixing the amine resin, the modification aid, the first catalyst, and a solvent which may be added or not added, to obtain a second component;

[0031] The first component and the second component are mixed to obtain the arc breakdown resistant insulating coating.

[0032] In one embodiment, the preparation method specifically includes: heating the dimer acid-modified epoxy resin to 50-70°C, adding benzylaminopropyltrimethoxysilane or benzylaminopropyltriethoxysilane under stirring, mixing evenly, adding a second catalyst and a diluent at least in batches, and continuing to heat to 60-80°C and maintain for 20-60 minutes to obtain a silicon-modified epoxy resin, wherein the mass ratio of the dimer acid-modified epoxy resin, benzylaminopropyltrimethoxysilane or benzylaminopropyltriethoxysilane, the second catalyst and the diluent is (90-110): (0.5-4.5): (0.1-0.3): (0-5).

[0033] Wherein, the second catalyst includes but is not limited to 2,4,6-tris(dimethylaminomethyl)phenol.

[0034] Wherein, the diluent includes but is not limited to xylene.

[0035] In one embodiment, the preparation method specifically includes: adding a dispersant additive to a modified epoxy resin, a silicon-modified epoxy and a flame retardant, mixing them evenly, and dispersing them at a high speed of 20-25 m / s for 8-15 minutes, then adding a defoamer and stirring until the mixture is evenly mixed, and then continuing to add functional fillers, pigments, and rheological additives under stirring conditions and mixing them evenly, and then dispersing them at a high speed of 20-25 m / s for 20-30 minutes. During the high-speed dispersion, the temperature is kept at 45-55°C. During the stirring process, the paint on the wall needs to be scraped off for 2-3 minutes / time to obtain the first component.

[0036] In one embodiment, the preparation method specifically includes: mixing the dispersant, dimer acid-modified epoxy resin, silicon-modified epoxy resin and flame retardant under stirring, and dispersing them at a linear speed of 20-25 m / s for 8-15 minutes, then adding the defoaming agent and stirring until the mixture is uniformly mixed, and then continuing to add the functional filler and pigment filler, and rheological additive under stirring and mixing them uniformly, and then dispersing them at a linear speed of 20-25 m / s for 20-30 minutes, and controlling the temperature at 45-55°C during the dispersion to obtain the first component.

[0037] In some more specific implementation cases, the preparation method includes the following steps:

[0038] (1) A certain amount of dimer acid-modified epoxy resin is placed in a reaction vessel and heated to 60° C., benzylaminopropyltrimethoxysilane is added under stirring, and after uniform stirring, a certain amount of 2,4,6-tris(dimethylaminomethyl)phenol and an appropriate amount of xylene are added dropwise, and the temperature is continued to be raised to 60-80° C. and maintained for 20-60 minutes, followed by reduced pressure distillation and cooling to obtain a silicon-modified epoxy resin;

[0039] (2) Add dimer acid modified epoxy resin and silicon modified epoxy resin to a stirring tank, start low speed stirring, add dispersant additive under stirring conditions, mix well and disperse at high speed for 10-15 minutes, then add defoamer and stir for more than 5 minutes until uniform;

[0040] (3) Under low-speed stirring conditions, functional fillers, pigment fillers, and rheological additives are sequentially added to the mixture obtained in step (2) and mixed evenly, and then dispersed at a high speed of 20-25 m / s for 20-30 min. During the high-speed dispersion, the temperature is kept at 45-55° C. During the stirring process, the paint on the wall needs to be scraped off for 2-3 minutes / time to obtain the first component.

[0041] (4) The amine resin is placed in a container, and the small molecule silane is slowly added under stirring conditions. The mixture is then stirred at a linear speed of 3-5 m / s for 1.5-2.5 hours. After the exotherm ends and the mixture is cooled to room temperature, the catalyst is added and dispersed evenly to obtain the second component.

[0042] A third aspect of the embodiments of the present invention provides the use of the arc breakdown resistant insulating coating in rail transit, particularly for coating on the pantograph.

[0043] A fourth aspect of the embodiments of the present invention provides a functional coating formed by the arc breakdown resistant insulating coating.

[0044] For example, in one embodiment, a functional coating structure is provided, which includes an arc-resistant coating formed of the arc-breakdown-resistant insulating coating.

[0045] Furthermore, the functional coating structure further includes an epoxy primer layer, which is arranged between the arc-resistant coating and the metal substrate.

[0046] Furthermore, the metal substrate includes but is not limited to a steel substrate.

[0047] A fifth aspect of an embodiment of the present invention provides a protective structure for a pantograph of a rail transit vehicle, comprising an arc-resistant coating formed by the arc-breakdown-resistant insulating coating, wherein the arc-resistant coating covers the surface of a metal substrate of the pantograph.

[0048] Furthermore, the surface of the metal substrate is pre-treated with an epoxy primer, and it can also be considered that an epoxy primer layer is provided between the arc-resistant coating and the metal substrate.

[0049] Furthermore, the metal substrate includes but is not limited to a steel substrate.

[0050] The sixth aspect of an embodiment of the present invention provides a method for protecting a pantograph of a rail transit vehicle, comprising: uniformly mixing the first component and the second component of the arc breakdown resistant insulating coating, then applying them on the surface of a metal substrate treated with epoxy primer and curing to form a protective coating.

[0051] The protective coating has a balance of electrical properties, mechanical properties, flame retardancy, thermal conductivity and other properties.

[0052] Compared with the existing technology, the technical solution provided by the present invention has at least the following advantages:

[0053] (1) The arc-breakdown-resistant insulating coating provided is suitable for coating the pantograph platform on the roof of rail transit vehicles, and the protective coating formed can produce excellent arc-breakdown-resistant insulating effect.

[0054] (2) The arc-breakdown-resistant insulating coating provided has good elongation at break after the coating is formed, overcoming the problem of easy cracking of the existing insulating coating, while having sufficient elastic modulus.

[0055] (3) The functional coating formed by the arc-breakdown resistant insulating coating provided can achieve a balance of electrical properties, mechanical properties, flame retardancy and thermal conductivity by modifying epoxy, balancing electrical strength and elongation, adding fillers with good insulation properties such as silicon carbide, aluminum oxide, aluminum hydroxide or silicon nitride whiskers, and adding halogen-free, low-smoke flame retardants. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0057] Figure 1 The arc breakdown strength test results of the coating of comparative example 1 are shown;

[0058] Figure 2 The test results of arc breakdown strength of the arc-resistant insulating coating material coated with Example 1 are shown. DETAILED DESCRIPTION

[0059] The present invention is further described below with reference to the accompanying drawings and several examples, but the present invention is not limited to the scope of the examples. The reagents and raw materials used in the following examples are all commercially available, for example, the dimer acid modified epoxy resin is Guodu 175LX-90, and the amine resin is Evonik 910 flexible polyamide curing agent. Test methods where specific conditions are not specified generally follow conventional conditions or those recommended by the respective manufacturers. In the following examples, low-speed stirring refers to a linear speed of 10 m / s or less, high-speed stirring refers to a linear speed of 20 m / s or more, and 10-20 m / s is considered medium-speed stirring.

[0060] Example 1 A method for preparing an arc-breakdown-resistant insulating coating comprises the following steps:

[0061] (1) 100 g of dimer acid-modified epoxy resin 175LX-90 was placed in a four-necked flask equipped with a thermometer, a stirrer, a constant pressure dropping funnel and a reflux condenser. The condensing water was opened and the temperature was raised to 60 ° C. 2.0 g of benzylaminopropyltrimethoxysilane was added under stirring. After stirring evenly, 0.15 g of 2,4,6-tris(dimethylaminomethyl)phenol and 2 g of xylene were added dropwise. The temperature was continued to rise to 70 ° C and maintained for 25 min. The reflux condenser was removed and the mixture was distilled under reduced pressure. After cooling, the silicon-modified epoxy resin was obtained.

[0062] (2) Add 70 g of the silicon-modified epoxy resin prepared in step (1) and 200 g of the dimer acid-modified epoxy resin into a stirring kettle and start stirring at a low speed. Add 100 g of triphenyl phosphate flame retardant and 17 g of DISPRBYK-110 dispersant under stirring, mix well and disperse at high speed for 15 minutes, then add 2 g of silicone defoamer BYK-066N and 43 g of xylene and stir for 5 minutes until uniform.

[0063] (3) Under low-speed stirring conditions, 50 g of magnesium hydroxide, 300 g of aluminum hydroxide, 200 g of aluminum oxide, and 15 g of titanium dioxide were added to the mixture obtained in step (2) in sequence, and dispersed at high speed for 25 minutes. During this period, the temperature was controlled at 55°C and maintained for 15 minutes. After cooling, the viscosity of the material was about 150,000 cps / 25°C, and the first component was obtained.

[0064] (4) 900g Evonik 910 flexible polyamide curing agent was put into a container, and 10g of β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane was slowly added under stirring. The mixture was stirred at a low speed for 2h. After the exotherm was completed and the mixture was cooled to room temperature, 30g of 2,4,6-tris(dimethylaminomethyl)phenol, 18g of n-butanol, and 42g of xylene were added. The mixture was dispersed for 5min until uniform, thereby obtaining the second component.

[0065] (5) The first component and the second component are mixed uniformly in a mass ratio of 5:1 to obtain an arc-breakdown-resistant insulating coating.

[0066] Example 2 A method for preparing an arc breakdown resistant insulating coating comprises the following steps:

[0067] (1) 100 g of dimer acid-modified epoxy resin 175LX-90 was placed in a four-necked flask equipped with a thermometer, a stirrer, a constant pressure dropping funnel and a reflux condenser. The condensing water was opened and the temperature was raised to 60 ° C. 2.0 g of benzylaminopropyltriethoxysilane was added under stirring. After stirring evenly, 0.15 g of 2,4,6-tris(dimethylaminomethyl)phenol and 2 g of xylene were added dropwise. The temperature was continued to rise to 70 ° C and maintained for 25 min. The reflux condenser was removed and the mixture was distilled under reduced pressure. After cooling, the silicon-modified epoxy resin was obtained.

[0068] (2) Add 72 g of the silicon-modified epoxy resin prepared in step (1) and 200 g of the dimer acid-modified epoxy resin into a stirring kettle and start stirring at a low speed. Add 100 g of tri(2-isopropylphenyl)phosphate flame retardant and 15 g of DISPERBYK-2155 dispersant under stirring, mix well and disperse at high speed for 15 minutes. Then add 2 g of silicone defoamer BYKA530 and 43 g of xylene and stir for 5 minutes until uniform.

[0069] (3) Under low-speed stirring conditions, 50 g of magnesium hydroxide, 300 g of aluminum hydroxide, 200 g of aluminum oxide, and 12 g of titanium dioxide were added to the mixture obtained in step (2) in sequence, and dispersed at high speed for 25 minutes. During this period, the temperature was kept at 50°C for 15 minutes. After cooling, the viscosity of the material was about 200,000 cps / 25°C, and the first component was obtained.

[0070] (4) 900g of Evonik epoxy resin 910 flexible polyamide curing agent was put into a container, 10g of β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane was slowly added under stirring, and stirring was continued at a low speed for 2h. After the exotherm ended and the mixture was cooled to room temperature, 30g of catalyst 2,4,6-tris(dimethylaminomethyl)phenol, 18g of n-butanol, and 42g of xylene were added, and the mixture was dispersed for 5min until uniform, thereby obtaining the second component.

[0071] (5) The first component and the second component are mixed uniformly in a mass ratio of 5:1 to obtain an arc-breakdown-resistant insulating coating.

[0072] Comparative Example 1 The preparation method of an insulating coating provided in this comparative example is substantially the same as that of Example 1, except that step (1) is omitted and 270 g of dimer acid-modified epoxy resin is used in step (2) instead of adding silicon-modified epoxy resin.

[0073] Comparative Example 2 The preparation method of an insulating coating provided in this comparative example is basically the same as that in Example 1, with the only difference being that β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane is not added in step (4).

[0074] Comparative Example 3 The preparation method of an insulating coating provided in this comparative example is basically the same as that in Example 1, except that:

[0075] Omit step (1).

[0076] (2) Add 1 g of benzylaminopropyltrimethoxysilane and 270 g of dimer acid-modified epoxy resin to a stirring kettle and start stirring at a low speed. Add 100 g of triphenyl phosphate flame retardant and 17 g of DISPRBYK-110 dispersant under stirring, mix well and disperse at high speed for 15 minutes, then add 2 g of silicone defoamer BYK-066N and 43 g of xylene and stir for 5 minutes until uniform.

[0077] Comparative Example 4 The preparation method of an insulating coating provided in this comparative example is basically the same as that in Example 1, except that:

[0078] Step (1) was omitted. 270 g of dimer acid-modified epoxy resin was used in step (2) without adding silicon-modified epoxy resin. Also, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane was not added in step (4).

[0079] Comparative Example 5 The preparation method of an insulating coating provided in this comparative example is basically the same as that in Example 1, except that:

[0080] Step (1) was omitted. In step (2), 250 g of 100% solids XA545 Jiadida elastic epoxy resin was used, and no silicon-modified epoxy resin was added. In step (4), β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane was not added. Furthermore, in step (5), the mass ratio of the first component to the second component was 4:1.

[0081] Comparative Example 6 The preparation method of an insulating coating provided in this comparative example is basically the same as that of Comparative Example 5, with the only difference being:

[0082] In step (2), no tri(2-isopropylphenyl)phosphate flame retardant was added; and in step (3), 50 g of talc and 300 g of barium sulfate were used, but magnesium hydroxide and aluminum hydroxide were not added.

[0083] Example 3 A method for preparing an arc-breakdown-resistant insulating coating comprises the following steps:

[0084] (1) 100 g of dimer acid-modified epoxy resin was placed in a four-necked flask equipped with a thermometer, a stirrer, a constant pressure dropping funnel and a reflux condenser, the condensing water was opened and the temperature was raised to 50°C, 2.5 g of benzylaminopropyltriethoxysilane was added under stirring, 0.15 g of 2,4,6-tris(dimethylaminomethyl)phenol and 2 g of xylene were added dropwise after stirring, the temperature was continued to be raised to 60°C and maintained for 60 min, the reflux condenser was removed and the mixture was distilled under reduced pressure, and the silicon-modified epoxy resin was obtained after cooling.

[0085] (2) Add 70 g of the silicon-modified epoxy resin prepared in step (1) and 200 g of the dimer acid-modified epoxy resin into a stirring kettle and start stirring at a low speed. Add 100 g of a triazine nitrogen flame retardant and 17 g of a DISPRBYK-110 dispersant under stirring, mix well, and disperse at a high speed for 15 minutes. Then, add 2 g of an organosilicon defoamer BYK-066N and 43 g of xylene and stir for 5 minutes until uniform.

[0086] (3) Under low-speed stirring conditions, 50 g of magnesium hydroxide, 300 g of aluminum hydroxide, 200 g of aluminum oxide, and 10 g of chrome black were added to the mixture obtained in step (2) in sequence, and the mixture was dispersed at high speed for 25 minutes. During this period, the temperature was controlled at 50-55°C and maintained for 15 minutes. After cooling, the viscosity of the material was about 200,000 cps / 25°C, thereby obtaining the first component.

[0087] (4) 900g of Evonik epoxy resin 910 flexible polyamide curing agent was put into a container, and 10g of β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane was slowly added under stirring. The mixture was stirred at a low speed for 2h. After the exotherm was completed and the mixture was cooled to room temperature, 30g of 2,4,6-tris(dimethylaminomethyl)phenol, 18g of n-butanol, and 42g of xylene were added. The mixture was dispersed for 5min until uniform, thereby obtaining the second component.

[0088] (5) The first component and the second component are mixed uniformly in a mass ratio of 5:1 to obtain an arc-breakdown-resistant insulating coating.

[0089] Example 4 A method for preparing an arc breakdown resistant insulating coating comprises the following steps:

[0090] (1) 100 g of dimer acid-modified epoxy resin was placed in a four-necked flask equipped with a thermometer, a stirrer, a constant pressure dropping funnel and a reflux condenser, the condensing water was opened and the temperature was raised to 70°C, 2.5 g of benzylaminopropyltriethoxysilane was added under stirring, 0.15 g of 2,4,6-tris(dimethylaminomethyl)phenol and 2 g of xylene were added dropwise after stirring, the temperature was continued to be raised to 80°C and maintained for 20 min, the reflux condenser was removed and the mixture was distilled under reduced pressure, and the silicon-modified epoxy resin was obtained after cooling.

[0091] (2) Add 90 g of the silicon-modified epoxy resin and 240 g of the dimer acid-modified epoxy resin obtained in step (1) into a stirring kettle and start stirring at a low speed. Add 100 g of tri(2-isopropylphenyl)phosphate flame retardant and 15 g of DISPERBYK-2155 dispersant under stirring, mix well and disperse at high speed for 15 minutes, then add 2 g of silicone defoamer BYKA530 and 30 g of xylene and stir for 5 minutes until uniform.

[0092] (3) Under low-speed stirring conditions, 50 g of magnesium hydroxide, 256 g of aluminum hydroxide, 200 g of aluminum oxide, and 12 g of rust red were added to the mixture obtained in step (2) in sequence, and the mixture was dispersed at high speed for 25 minutes. During this period, the temperature was controlled at 50-55°C and maintained for 15 minutes. After cooling, the viscosity of the material was about 180,000 cps / 25°C, and the first component was obtained.

[0093] (4) 900g of Evonik epoxy resin 910 flexible polyamide curing agent was put into a container, 10g of γ-glycidoxytrimethoxysilane was slowly added under stirring, and stirring was continued at a low speed for 2h. After the exotherm ended and the mixture was cooled to room temperature, 30g of catalyst 2,4,6-tris(dimethylaminomethyl)phenol, 18g of n-butanol, and 43g of xylene were added, and the mixture was dispersed for 5min until uniform, thereby obtaining the second component.

[0094] (5) The first component and the second component are mixed uniformly in a mass ratio of 4:1 to obtain an arc-breakdown-resistant insulating coating.

[0095] Various properties of the arc breakdown resistant insulating coatings and the paint films formed therefrom according to Examples 1-4 and Comparative Examples 1-6 were tested, and the results are shown in Tables 1-2 below. The individual tests in Table 1 were conducted on multiple products according to Examples 1-4, and the test results for items 1-11 of these multiple products were consistent. The test results are the average of the relevant test data for these multiple products.

[0096] Table 1 Performance test results of the coatings and paint films of Examples 1-4

[0097]

[0098]

[0099] The properties of the paint films formed by the arc breakdown resistant insulating coatings of Examples 1-4 and the insulating coatings of Comparative Examples 1-6 were further tested, and the corresponding test results are shown in Table 2. The test results in Table 2 are the average values ​​of the test results of multiple batches of products.

[0100] Table 2 Test results of the paint film properties formed by the insulating coatings of Examples 1-4 and Comparative Examples 1-6

[0101]

[0102]

[0103] To obtain the test results shown in Tables 1 and 2, the test methods used in this manual are as follows:

[0104] The non-volatile matter content is tested according to GB / T 1725-2007; the drying time is tested according to GB / T 1728-1979; the performance during the trial period is tested according to HG / T 5367.2-2020; the tensile strength is tested according to GB / T 528-2009; the elongation at break is tested according to GB / T 528-2009; the appearance of the coating is tested according to HG / T 5367.2-2020; the flexibility is tested according to GB / T 1731-1993; the impact resistance is tested according to GB / T 1732-19930; the volume resistivity is tested according to GB / T 1410-2006; the electrical strength is tested according to GB / T 1408.1-2016; the heat resistance (100±2)℃ is tested according to GB / T 1735-2009; the water resistance is tested according to GB / T 1733-1993; liquid resistance is tested according to GB / T 9274-1988; the cross-scratch test is tested according to GB / T 31586.2-2015; and pull-off adhesion is tested according to GB / T 5210-2006. Flame retardancy is tested according to UL94-2020; thermal conductivity is measured according to GB / T10297-2015.

[0105] For the fracture productivity and tensile strength tests shown in Table 2, two coats were applied, 12 to 24 hours apart. The dry film thickness of each coat was essentially the same, with a total dry film thickness of (2000 ± 200) μm. The coats were then removed from the mold after 7 days of aging. The specimens were placed face-up in a (50 ± 2)°C drying oven, with a minimum distance of 50 mm between the specimen and the oven wall. After 7 days of constant temperature, the specimens were removed and tested for performance after 24 hours of aging. For the volume resistivity and electrical strength tests, flexibility, impact resistance, heat resistance, film appearance, scratch test, and acid and alkali resistance, each coat was applied with a dry film thickness of (1000 ± 100) μm. Steel plates were used as the substrate for the coating appearance, impact resistance, heat resistance, and dielectric resistance tests; tinplate plates were used for flexibility testing. Thin sheets of polytetrafluoroethylene sheeting were used for the volume resistivity, electrical strength, tensile strength, and elongation at break.

[0106] The arc-breakdown-resistant insulating coatings prepared in Examples 1-4 above have a volume resistivity greater than 10 11 Ω·m, electrical strength greater than 15kV / mm, tensile strength greater than 2.0MPa, elongation at break greater than 50%, and normal coating appearance. This may be due to the improved compatibility between the silicone-modified epoxy resin and the dimer acid-modified epoxy resin, which also improves the coating of the powder, reduces internal stress, and achieves a more uniform paint film.

[0107] The insulating coatings prepared in the above control examples 1-6 have paint films that are slightly inferior to the test results of the paint films of Examples 1-4 in terms of conventional physical properties, and are far lower than Examples 1-4 in terms of various key resistance tests, especially the volume resistivity and electrical strength. The appearance of the paint film is worse than that of Examples 1-4. Although control example 4 uses all modified resins, it has a higher viscosity, uneven mixing during scraping, and low electrical properties.

[0108] The high arc breakdown resistant insulating coatings prepared in Examples 1-4 all have good performance, and the volume resistivity of the paint films is greater than 5*10 11 Ω·m, electrical strength greater than 20KV / mm, tensile strength greater than 3.0MPa, and elongation at break greater than 150%; the coating is applied to the pantograph platform on the roof of rail transit vehicles, and its performance balance surpasses similar products on the market.

[0109] The flame retardancy of the highly arc-breakdown-resistant insulating coatings prepared in Examples 1-4 is significantly better than that of Control Examples 5-6.

[0110] The high arc breakdown resistant insulating coating of Example 1 and the insulating coating of Control Example 1 were coated on a polytetrafluoroethylene sheet to form a paint film. The paint film was applied in two coats, with an interval of 12h to 24h. The dry film thickness of each coat was basically the same, and the total dry film thickness was (2000±200)μm. The dry film thickness of each coat was basically the same. After 7 days of placement, the mold was removed. After demoulding, the reverse side was upward and placed in a drying oven at (50±2)℃. The distance between the test piece and the drying oven wall was not less than 50mm. After 7 days of constant temperature, the test piece was taken out. The surface of the coating of Control Example 1 had rust spots. Figure 1 , while the coating surface of Example 1 is intact, see Figure 2 .

[0111] The above-described embodiments merely illustrate several implementations of the present invention, and while their descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the patent for this invention shall be determined by the appended claims.

Claims

1. An arc-breakdown-resistant insulating coating, characterized in that: include: The first component comprises the following components calculated by weight: 20-35 parts of dimer acid modified epoxy resin 1-10 parts of silicon-modified epoxy resin 5-10 parts flame retardant Rheological additive 0-2 parts Dispersant 0.1-1 part 40-75 parts of functional filler 0-2 parts of pigments and fillers 0.1-3 parts defoaming agent 0-4 parts of solvent; The second component comprises the following components calculated by weight: 75-95 parts of amine resin 0.5-5 parts of modification additive 1-5 parts of the first catalyst 0-12 parts of solvent; The preparation method of the silicon-modified epoxy resin is as follows: heating the dimer acid-modified epoxy resin to 50-70°C, adding benzylaminopropyltrimethoxysilane or benzylaminopropyltriethoxysilane under stirring, mixing evenly, adding the second catalyst and diluent in batches, and continuing to heat to 60-80°C and maintaining for 20-60 minutes to obtain the silicon-modified epoxy resin.

2. The arc-breakdown-resistant insulating coating according to claim 1, characterized in that: The silicon-modified epoxy resin includes any one of a benzylaminopropyltrimethoxysilane-modified dimer acid-modified epoxy resin and a benzylaminopropyltriethoxysilane-modified dimer acid-modified epoxy resin.

3. The arc-breakdown-resistant insulating coating according to claim 1, characterized in that: The flame retardant includes any one or more combinations of phosphate flame retardants, melamine, dicyandiamide, melamine salts, triazine nitrogen flame retardants, and polysiloxane flame retardants.

4. The arc-breakdown-resistant insulating coating according to claim 1, characterized in that: The rheological additive includes any one or more combinations of polyethylene wax, fumed silica, hydrogenated castor oil, polyurethane, bentonite, and polyamide wax.

5. The arc-breakdown-resistant insulating coating according to claim 1, characterized in that: The dispersant includes any one or more combinations of alkylammonium salts containing high molecular weight copolymers, high polarity linear polymers, and modified polyurethane polymers.

6. The arc-breakdown-resistant insulating coating according to claim 1, characterized in that: The functional filler includes any one or more combinations of ceramic silicon micropowder, talc powder, silicon carbide, boron nitride, mica powder, aluminum hydroxide, magnesium hydroxide, aluminum oxide, and magnesium oxide.

7. The arc-breakdown-resistant insulating coating according to claim 1, characterized in that: The defoaming agent includes any one or more combinations of organosilicon defoaming agents and organosilicon modified defoaming agents.

8. The arc-breakdown-resistant insulating coating according to claim 1, characterized in that: The solvent includes any one or more combinations of benzene solvents, n-butanol, and butanone.

9. The arc-breakdown-resistant insulating coating according to claim 1, characterized in that: The amine resin includes any one or more combinations of polyetheramine curing agents or polyamide adduct curing agents.

10. The arc-breakdown-resistant insulating coating according to claim 1, characterized in that: The first catalyst includes any one or more combinations of tertiary amine catalysts, phenol catalysts, or cross-linking catalysts.

11. The arc-breakdown-resistant insulating coating according to claim 1, characterized in that: The modification aid includes any one or more combinations of γ-glycidoxytrimethoxysilane and β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane.

12. The arc-breakdown-resistant insulating coating according to claim 1, characterized in that: The mass ratio of the first component to the second component is 4-6:

1.

13. A method for preparing an arc-breakdown-resistant insulating coating, characterized in that: include: The composition and preparation of raw materials according to any one of claims 1 to 12 of the arc-breakdown resistant insulating coating; reacting the dimer acid-modified epoxy resin with benzylaminopropyltrimethoxysilane or benzylaminopropyltriethoxysilane in the presence of a second catalyst to prepare a silicon-modified epoxy resin; The silicon-modified epoxy resin is mixed evenly with a dimer acid-modified epoxy resin, a rheological additive, a dispersant, a defoamer, a flame retardant, a pigment, a functional filler and a solvent, or the silicon-modified epoxy resin is mixed evenly with a dimer acid-modified epoxy resin, a dispersant, a defoamer, a flame retardant, a pigment, a functional filler and a solvent, or the silicon-modified epoxy resin is mixed evenly with a dimer acid-modified epoxy resin, a rheological additive, a dispersant, a defoamer, a flame retardant, a pigment, a functional filler and a solvent, or the silicon-modified epoxy resin is mixed evenly with a dimer acid-modified epoxy resin, a dispersant, a defoamer, a flame retardant, a pigment, a functional filler and a solvent, to obtain a first component; The amine resin, the modification aid, the first catalyst and the solvent are uniformly mixed, or the amine resin, the modification aid and the first catalyst are uniformly mixed to obtain a second component; The first component and the second component are mixed to obtain the arc breakdown resistant insulating coating.

14. The preparation method according to claim 13, characterized in that Specifically include: The dimer acid-modified epoxy resin is heated to 50-70° C., and benzylaminopropyltrimethoxysilane or benzylaminopropyltriethoxysilane is added under stirring. After mixing evenly, a second catalyst and a diluent are added in batches, and the temperature is continued to be raised to 60-80° C. and maintained for 20-60 minutes to obtain a silicon-modified epoxy resin, wherein the mass ratio of the dimer acid-modified epoxy resin, benzylaminopropyltrimethoxysilane or benzylaminopropyltriethoxysilane, the second catalyst and the diluent is (90-110):(0.5-4.5):(0.1-0.3):(0-5).

15. The preparation method according to claim 13, characterized in that Specifically include: At room temperature and with stirring, a dispersant, a dimer acid-modified epoxy resin, a silicon-modified epoxy resin, and a flame retardant are mixed uniformly and dispersed at a linear speed of 20-25 m / s for 8-15 minutes. A defoamer is then added and stirred until the mixture is uniformly mixed. Subsequently, functional fillers, pigments, and rheological additives are added and mixed uniformly under stirring. The mixture is then dispersed at a linear speed of 20-25 m / s for 20-30 minutes, and the temperature is controlled at 45-55° C. during the dispersion period to obtain the first component.

16. The preparation method according to claim 13, characterized in that Specifically include: At room temperature and with stirring, the modification aid is slowly added to the amine resin, and then stirred continuously at a linear speed of 3-5 m / s for 1.5-2.5 hours. After the exotherm ends and the mixture is cooled to room temperature, the first catalyst is added and dispersed evenly to obtain the second component.

17. A functional coating structure, characterized in that: The invention comprises an arc-resistant coating formed by the arc-breakdown-resistant insulating coating material according to any one of claims 1 to 12.

18. The functional coating structure according to claim 17, characterized in that: The invention also includes an epoxy primer layer, which is disposed between the arc-resistant coating and the metal substrate.

19. The functional coating structure according to claim 18, characterized in that: The metal substrate includes a steel substrate.

20. A protective structure for a pantograph of a rail transit vehicle, characterized in that: The invention comprises an arc-resistant coating formed by the arc-breakdown-resistant insulating coating according to any one of claims 1 to 12, wherein the arc-resistant coating covers the surface of the metal substrate of the pantograph.

21. The pantograph protection structure of a rail transit vehicle according to claim 20, characterized in that: An epoxy primer layer is provided between the arc-resistant coating and the metal substrate.

22. The pantograph protection structure of a rail transit vehicle according to claim 20, characterized in that: The metal substrate includes a steel substrate.

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