Flame-retardant coating as well as preparation method and use method of flame-retardant coating

Abstract

The invention relates to a flame-retardant coating, a preparation method of the flame-retardant coating and a use method of the flame-retardant coating, and relates to the technical field of flame-retardant materials. The component A is prepared from the following components in percentage by weight: 29.95 to 35.00 percent of epoxy resin, 5.99 to 7.00 percent of toughened resin, 9.00 to 11.45 percent of a solvent, 19.64 to 24.00 percent of coated ammonium polyphosphate, 6.55 to 8.00 percent of modified pentaerythritol, 6.55 to 8.00 percent of melamine, 0 to 10.00 percent of graphene oxide, 4.91 to 6.00 percent of an organic flame retardant, 1.64 to 2.00 percent of an inorganic flame retardant and 1.00 to 4.91 percent of an auxiliary agent; and the component B is prepared from the following components in percentage by weight: 47.76 to 58.30 percent of epoxy curing agent and 41.70 to 52.24 percent of solvent. The heat dissipation capability of the flame-retardant coating can be improved, and the flame-retardant coating can maintain a good expansion effect; and moreover, in a high-temperature and humid environment, the attenuation amount of the heat insulation efficiency of the flame-retardant material is relatively small, and the safety of application in a severe scene is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of flame retardant materials, and in particular to a flame retardant coating, a preparation method of the flame retardant coating and a use method thereof. Background Art

[0002] Since 2019, there have been at least hundreds of new energy vehicle fires in China, most of which were caused by power battery failures. Power batteries, especially lithium-ion batteries, are prone to "thermal runaway." Lithium batteries are electrochemical power sources. After a thermal runaway reaction occurs, the reaction speed is fast and almost uncontrollable, accompanied by a strong flame impact force, and the temperature is as high as 1600°C. In other words, fires caused by collision, extrusion and deformation of existing new energy vehicle power batteries, especially lithium-ion batteries, have become an important issue affecting the safety of passengers and property. Therefore, how to improve the fire safety performance of battery packs and thus ensure the safety of passengers in new energy vehicles has become the primary safety issue.

[0003] At present, in order to reduce the probability of thermal runaway reaction of power batteries, most of them are coated with intumescent fire retardant coatings. At present, the intumescent fire retardant coating with ammonium polyphosphate (APP) / pentaerythritol (PERM) / melamine (EL) as the intumescent flame retardant system (IFR) is the mainstream intumescent fire retardant coating. This system mainly relies on the thermal decomposition of IFR and the formation of intumescent carbon layer by esterification reaction and dehydration carbonization reaction of IFR to achieve the purpose of flame retardancy and heat insulation.

[0004] With respect to the above technical solution, the conventional ammonium polyphosphate (APP) / pentaerythritol (PERM) / melamine (EL) intumescent flame retardant system (IFR) has poor heat dissipation effect when the power battery does not experience thermal runaway, that is, during the charging process of the power battery, the heat generated by the power battery is not easily dissipated, but instead increases the probability of thermal runaway of the power battery. Summary of the invention

[0005] In order to improve the heat dissipation effect of a power battery when thermal runaway does not occur, and to provide good protection when thermal runaway occurs in the power battery, the present invention provides a flame retardant coating, a preparation method of the flame retardant coating, and a use method thereof.

[0006] In the first aspect, the present invention provides a flame retardant coating, which adopts the following technical solution: A flame retardant coating, comprising by weight: component A and component B, The weight percentage of component A includes: epoxy resin 29.95-35.00%, toughening resin 5.99-7.00%, solvent 9.00-11.45%, coated polyphosphate amine 19.64-24.00%, modified pentaerythritol 6.55-8.00%, melamine 6.55-8.00%, graphene oxide 0-10.00%, organic flame retardant 4.91-6.00%, inorganic flame retardant 1.64-2.00%, additive 1.00-4.91%; The weight percentages of component B include: 47.76-58.30% of epoxy curing agent and 41.70-52.24% of solvent.

[0007] Optionally, the epoxy resin is selected from at least one of bisphenol A epoxy resin, bisphenol F epoxy resin, and epoxy ester resin.

[0008] Optionally, the toughening resin is selected from at least one of epoxidized soybean oil, DOP, and carboxyl-terminated liquid nitrile rubber.

[0009] Optionally, the solvent is selected from at least one of xylene, isobutanol and n-butanol.

[0010] Optionally, the coated polyphosphate amine is selected from at least one of melamine-coated polyphosphate amine and silane-coated polyphosphate amine.

[0011] Optionally, the melamine is selected from at least one of Sinopharm Reagent melamine and Aladdin Reagent melamine.

[0012] Optionally, the graphene oxide is selected from at least one of microcrystalline technology graphene oxide, sixth element graphene oxide, and two-dimensional carbon graphene oxide.

[0013] Optionally, the organic flame retardant is a halogen-free flame retardant selected from at least one of phosphates and their derivatives, phosphonates, phosphites, phosphorus-containing polyols and phosphorus-nitrogen compounds, and melamine salts.

[0014] Optionally, the inorganic flame retardant is selected from at least one of boehmite, antimony pentoxide, magnesium hydroxide, aluminum oxide, and antimony trioxide.

[0015] Optionally, the auxiliary agent is selected from at least one of a leveling agent, a defoaming agent and a dispersant.

[0016] Optionally, the epoxy curing agent is selected from at least one of polyamide, polyetheramine, aliphatic amine, aromatic amine, alicyclic amine, imidazoles and acid anhydrides.

[0017] Optionally, the modified pentaerythritol is prepared by the following steps: 1 mol of melamine, 2.5 mol of paraformaldehyde and 1 L of deionized water were added to a 2 L three-necked flask equipped with a reflux condenser, a stirrer and a thermometer, and the pH value of the material was adjusted to 9 with a 10% sodium hydroxide solution, and then the temperature was raised to 75°C for reaction for 1 hour, and then the temperature of the material was lowered to 55°C, and 4.5 mol of pentaerythritol was added, and the pH value of the material was adjusted to 1.5 with a 20% hydrochloric acid, and the reaction was carried out at 55±5°C for 2.5 hours, and then the temperature was raised to 80±5°C for further reaction for 2 hours. After the reaction, the pH value of the material was adjusted to 9 with a 10% sodium hydroxide solution, and the material was cooled to room temperature, filtered with a filter cake, and the filter cake was washed with deionized water. The obtained filter cake was dried at 150°C for 3 hours to obtain a modified pentaerythritol product.

[0018] Optionally, the ratio of the coated polyphosphate ammonium, modified pentaerythritol and melamine is 3:1:1.

[0019] In a second aspect, the present invention provides a method for preparing a flame retardant coating, which adopts the following technical solution: A method for preparing component A comprises the following steps: a. Weigh epoxy resin, toughening resin, coated polyphosphate amine, modified pentaerythritol, melamine, graphene oxide, organic flame retardant, inorganic flame retardant and additives according to the proportion of each substance in component A of the flame retardant coating described in the first aspect; b. Add epoxy resin, toughening resin and solvent into a stirring tank, stir at a speed of 500-700 r / min, and add coated polyphosphate amine, modified pentaerythritol, melamine, graphene oxide, organic flame retardant, inorganic flame retardant and additives during stirring; c. Continue stirring at a speed of 1500-2000 r / min and take samples continuously until the fineness is less than 20 μm as tested by a scraper fineness meter; d. Filter with 200-mesh filter cloth and package.

[0020] A method for preparing component B comprises the following steps: e. Weighing the epoxy curing agent and the solvent according to the proportion of the various substances in component B of the flame retardant coating described in the first aspect; f. Add epoxy curing agent and solvent into the stirring tank at a stirring speed of 800-1000 r / min until the epoxy curing agent is completely dissolved; g. Filter through a 300-mesh filter and repackage.

[0021] In a third aspect, the present invention provides a method for using a flame retardant coating, which adopts the following technical solution: A method for using a flame retardant coating comprises the following steps: h. Wipe the surface of the object to be coated with alcohol, and then treat the surface of the object to be coated with a coupling agent to remove all kinds of oil and dust on the surface of the object to be coated; i. Mix component A and component B in a mass ratio of 1:0.3; spray on the workpiece with a high-pressure spray gun, the coating thickness is between 2 and 3 mm, and cure at room temperature for 48 hours.

[0022] Optionally, in step i, three sprayings are performed, and the total thickness after three sprayings is between 2 and 3 mm. After the first spraying and the second spraying, they are cured at room temperature for 24 hours, and after the third spraying, they are cured at room temperature for 48 hours.

[0023] In a fourth aspect, the present invention provides a product using a flame retardant coating, which adopts the following technical solution: A product using a flame retardant coating, which is coated with the coating film as described in the third aspect.

[0024] In summary, the present invention includes at least one of the following beneficial technical effects: 1. By using pentaerythritol coated with ammonium polyphosphate and modified with melamine formaldehyde resin, the water resistance of the flame retardant material can be improved, and it is not easy to lose performance in a high humidity and water environment; when a collision occurs and thermal runaway occurs, the flame retardant coating can expand rapidly to block the air, and the insulation layer is not prone to defects, which slows down the burning speed of the battery and provides sufficient time for people in the car to escape.

[0025] 2. By using graphene oxide, graphene can only dissipate heat without conducting electricity, so that the flame retardant coating has good heat dissipation under normal conditions, reducing the probability of thermal runaway during the charging and discharging process, thereby reducing the probability of spontaneous combustion of the car during charging. DETAILED DESCRIPTION

[0026] The present invention is further described in detail below with reference to the embodiments.

[0027] Existing intumescent fire retardant coatings with ammonium polyphosphate (APP) / pentaerythritol (PERM) / melamine (EL) as intumescent flame retardant system (IFR) mainly rely on the thermal decomposition of IFR and the formation of an intumescent carbon layer by esterification and dehydration carbonization reaction of IFR to achieve the purpose of flame retardancy and heat insulation. Intumescent flame retardants have three basic elements, namely, acid source-ammonium polyphosphate (APP), carbon source-pentaerythritol (PERM) and gas source-melamine (EL).

[0028] Acid source is also called dehydrating agent or carbonization accelerator. It is generally an inorganic acid or a compound that can generate acid in situ during combustion, such as phosphoric acid, boric acid, sulfuric acid and phosphate ester. Carbon source is also called carbonizing agent. It is the basis for forming the foam carbonization layer. It is mainly some polyhydroxy compounds with high carbon content, such as starch, sucrose, dextrin, pentaerythritol, ethylene glycol, phenolic resin, etc. Gas source is also called foaming source. It is a nitrogen-containing compound, such as urea, melamine, polyamide, etc. Among the three components, the acid source is the most important and has the largest proportion. The flame retardant elements are contained in the acid source, so the acid source is a true flame retardant, and the carbon source and foaming agent are synergists.

[0029] The flame retardant effect of IFR mainly relies on the formation of a porous foam carbon layer on the surface of the material. It is a multiphase system containing solid, liquid and gaseous products. The flame retardant properties of the carbon layer are mainly reflected in: making it difficult for heat to penetrate the condensed phase, preventing oxygen from entering the combustion area, and preventing the gaseous or liquid products generated by degradation from overflowing the surface of the material. The process of char layer formation is: at about 150°C, the acid source produces an acid that can esterify polyols and can be used as a dehydrating agent; at a slightly higher temperature, the acid and the carbon source undergo an esterification reaction, and the amine group in the intumescent flame retardant system acts as a catalyst for the esterification reaction to accelerate the reaction; the intumescent flame retardant system melts before and during the esterification reaction, and the non-flammable gas produced during the reaction causes the system that is already in a molten state to expand and foam. At the same time, the polyols and esters are dehydrated and carbonized to form inorganic substances and carbon residues, and the system further foams; when the reaction is close to completion, the system gels and solidifies, and finally forms a porous foam carbon layer.

[0030] However, since the power battery generates heat when charging, and the flame retardant nature of the carbon layer makes it difficult for heat to penetrate the condensed phase, the original IFR has poor heat dissipation effect when the power battery does not have thermal runaway, which further leads to a high temperature inside the power battery. As the temperature of the power battery rises, it will cause a slow esterification reaction between the acid and the carbon source, which will easily lead to a large attenuation of the IFR thermal insulation efficiency.

[0031] The reagents and instruments used in the following examples can all be purchased from commercial sources.

[0032] The epoxy resin is selected from any one or more of E-51, E-44, F-51, F-44, 128 of Sanmu Group and Nanya Group.

[0033] The toughening resin is selected from any one or more of the carboxyl-terminated nitrile liquid rubber CTBN produced by Hubei Xinyuhong Biomedical Technology Co., Ltd., epoxidized soybean oil produced by Yancheng Xinjinyuan Oil Technology Co., Ltd., chlorinated paraffin-52, and environmentally friendly plasticizer T60.

[0034] The solvent is selected from any one or more of xylene with a purity of ≥99.0%, n-butanol with a purity of ≥99.0%, and isobutanol with a purity of ≥99.0% produced by Sinopharm Chemical Reagent Co., Ltd.

[0035] The coated amine polyphosphate is selected from the melamine-coated ammonium polyphosphate produced by Shenzhen Zhongherun Technology Co., Ltd.

[0036] Pentaerythritol was selected from pentaerythritol with a purity of ≥99.0% from Sinopharm Chemical Reagent Co., Ltd.

[0037] Paraformaldehyde was selected from Sinopharm Chemical Reagent Co., Ltd. with a purity of ≥95.0%.

[0038] Melamine is selected from melamine with a purity of ≥99.0% produced by Sinopharm Chemical Reagent Co., Ltd.

[0039] The graphene oxide is selected from the graphene oxide of the sixth element material technology co., LTD. in suzhou with pH value of 5.0-7.0, carbon mass fraction of 55-65%, D50 particle size of 10-20 μm, model SE2431.

[0040] The organic flame retardant is selected from Dongguan Doher Chemical Co., Ltd.'s halogen-free environmentally friendly silicone rubber flame retardant doher-601R, halogen-free phosphorus fire retardant 601, tape flame retardant Doher-831, and ultra-fine environmentally friendly powder fire retardant 101.

[0041] The inorganic flame retardant is selected from boehmite produced by Anhui Yishitong Materials Technology Co., Ltd.

[0042] The additive is selected from BYK-333 organosilicon leveling agent and TEGO-450 organosilicon leveling agent; the defoamer is any one or more of BYK-077 organosilicon defoamer and TEGO Foamex N organosilicon defoamer, Shenzhu SN-1831 dispersant and Shenzhu SN-2011 dispersant.

[0043] The epoxy curing agent is selected from any one or more of 650 polyamide curing agent, 651 polyamide curing agent of Sanmu Group, D-2000 polyetheramine curing agent, D-5000 polyetheramine curing agent and H-113B aromatic amine modified curing agent of Chuzhou Huisheng Electronic Materials Co., Ltd.

[0044] Example 1: This example discloses a flame retardant coating, a preparation method of the flame retardant coating and a use method thereof, wherein the flame retardant coating comprises component A and component B, and the weight percentages of component A include: 33.86% epoxy resin, 6.77% toughening resin, 9.67% solvent, 23.22% coated polyphosphate amine, 7.74% modified pentaerythritol, 7.74% melamine, 2.00% graphene oxide, 5.80% organic flame retardant, 1.93% inorganic flame retardant, and 1.27% additive.

[0045] The weight percentages of component B include: 56.43% epoxy curing agent and 43.57% solvent.

[0046] Wherein, the modified pentaerythritol in component A is prepared by the following method: 1 mol of melamine, 2.5 mol of paraformaldehyde and 1 L of deionized water were added to a 2 L three-necked flask equipped with a reflux condenser, a stirrer and a thermometer, and the pH value of the material was adjusted to 9 with a 10% sodium hydroxide solution, and then the temperature was raised to 75°C for reaction for 1 hour, and then the temperature of the material was lowered to 55°C, and 4.5 mol of pentaerythritol was added, and the pH value of the material was adjusted to 1.5 with a 20% hydrochloric acid, and the reaction was continued at 55±5°C for 2.5 hours, and then the temperature was raised to 80±5°C for further reaction for 2 hours. After the reaction, the pH value of the material was adjusted to 9 with a 10% sodium hydroxide solution, and the material was cooled to room temperature, filtered with 3 1 L filter cakes, and the filter cake was washed with deionized water for 3 times. The obtained filter cake was dried at 150°C for 3 hours to obtain the modified pentaerythritol product.

[0047] The component A of the flame retardant coating of this embodiment is prepared by the following steps: a. Epoxy resin, toughening resin, coated polyphosphate amine, modified pentaerythritol, melamine, graphene oxide, organic flame retardant, inorganic flame retardant and auxiliary agent are weighed according to the proportion of each substance in component A of the flame retardant coating of Example 1; b. Add epoxy resin, toughening resin and solvent into a stirring tank, stir at a speed of 500-700 r / min, and add coated polyphosphate amine, modified pentaerythritol, melamine, graphene oxide, organic flame retardant, inorganic flame retardant and additives during stirring; c. Continue stirring at a speed of 1500-2000 r / min and take samples continuously until the fineness is less than 20 μm as tested by a scraper fineness meter; d. Filter with 200-mesh filter cloth and package.

[0048] In the process of preparing component A, the epoxy resin and toughening resin are first mixed and stirred evenly, and then other components are added during the stirring process; this method of adding and stirring can fully stir and disperse all the substances evenly. Then, filter cloth or filter screen is used to remove particles or impurities in the components that have not been stirred and dispersed.

[0049] The B component of the flame retardant coating of this embodiment is prepared by the following steps: e. Weigh the epoxy curing agent and solvent according to the proportion of each substance in component B of the flame retardant coating in Example 1; f. Add epoxy curing agent and solvent into the stirring tank at a stirring speed of 800-1000 r / min until the epoxy curing agent is completely dissolved; g. Filter through a 300-mesh filter and repackage.

[0050] The method of using the flame retardant coating in this embodiment is as follows: the flame retardant material is applied to a power battery pack.

[0051] First, pre-treat the surface of the power battery pack, wipe it with alcohol to eliminate all kinds of oil and dust on the surface of the object to be coated, and brush the coupling agent solution on the surface of the power battery pack to make the coupling agent fully contact with the treated surface. Then mix component A and component B in a ratio of 1:0.3, and spray them on the workpiece with a high-pressure spray gun. The thickness of each spray is about 1mm. After curing for 24 hours, the next spray is carried out. After three sprayings, the coating thickness is between 2~3mm, and it is cured at room temperature for 48 hours. When spraying once, defects such as pinholes and pitting are prone to occur. After three sprayings, the defects of the coating can be basically completely covered, thereby ensuring the protective effect of the flame retardant material.

[0052] Example 2: This example discloses a flame retardant coating, a preparation method and a use method of the flame retardant coating. The ratio of component A to component B in this example is different from that in Example 1. During the preparation of component A and component B, except that the ratio of each raw material changes according to the actual content of this example, everything else is the same as in Example 1.

[0053] The weight percentages of component A include: 32.62% epoxy resin, 6.52% toughening resin, 10.25% solvent, 22.37% coated polyphosphate amine, 7.46% modified pentaerythritol, 7.46% melamine, 4.00% graphene oxide, 5.59% organic flame retardant, 1.86% inorganic flame retardant, and 1.87% additive.

[0054] The weight percentages of component B include: 54.37% epoxy curing agent and 45.63% solvent.

[0055] Example 3: This example discloses a flame retardant coating, a preparation method and a use method of the flame retardant coating. The ratio of component A to component B in this example is different from that in Example 1. During the preparation of component A and component B, except that the ratio of each raw material changes according to the actual content of this example, everything else is the same as Example 1.

[0056] The weight percentages of component A include: 31.33% epoxy resin, 6.27% toughening resin, 10.74% solvent, 21.49% coated polyphosphate amine, 7.16% modified pentaerythritol, 7.16% melamine, 6.00% graphene oxide, 5.37% organic flame retardant, 1.79% inorganic flame retardant, and 2.69% additive.

[0057] The weight percentages of component B include: 52.22% epoxy curing agent and 47.78% solvent.

[0058] Example 4: This example discloses a flame retardant coating, a preparation method and a use method of the flame retardant coating. The ratio of component A to component B in this example is different from that in Example 1. During the preparation of component A and component B, except that the ratio of each raw material changes according to the actual content of this example, everything else is the same as in Example 1.

[0059] The weight percentages of component A include: 29.95% epoxy resin, 5.99% toughening resin, 11.13% solvent, 20.54% coated polyphosphate amine, 6.85% modified pentaerythritol, 6.85% melamine, 8.00% graphene oxide, 5.13% organic flame retardant, 1.71% inorganic flame retardant, and 3.85% additive.

[0060] The weight percentages of component B include: 49.92% epoxy curing agent and 50.08% solvent.

[0061] Comparative Example 1: This comparative example discloses a flame retardant coating, a preparation method and a use method of the flame retardant coating. The ratio of component A to component B in this comparative example is different from that in Example 1. During the preparation of component A and component B, except that the ratio of each raw material changes according to the actual content of this comparative example, everything else is the same as in Example 1.

[0062] The weight percentages of component A include: 35.00% epoxy resin, 7.00% toughening resin, 9.00% solvent, 24.00% coated polyphosphate amine, 8.00% modified pentaerythritol, 8.00% melamine, 0% graphene oxide, 6.00% organic flame retardant, 2.00% inorganic flame retardant, and 1.00% additive.

[0063] The weight percentages of component B include: 58.30% epoxy curing agent and 41.70% solvent.

[0064] Comparative Example 2: This comparative example discloses a flame retardant coating, a preparation method and a use method of the flame retardant coating. The ratio of component A to component B in this comparative example is different from that in Example 1. During the preparation of component A and component B, except that the ratio of each raw material changes according to the actual content of this comparative example, everything else is the same as in Example 1.

[0065] The weight percentages of component A include: 29.95% epoxy resin, 5.99% toughening resin, 11.45% solvent, 19.64% coated polyphosphate amine, 6.55% modified pentaerythritol, 6.55% melamine, 10.00% graphene oxide, 4.91% organic flame retardant, 1.64% inorganic flame retardant, and 3.32% additives.

[0066] The weight percentages of component B include: 47.76% epoxy curing agent and 52.24% solvent.

[0067] Comparative Example 3: This comparative example discloses a flame retardant coating, a preparation method and a use method of the flame retardant coating. The ratio of component A to component B in this comparative example is different from that in Example 1. During the preparation of component A and component B, except that the ratio of each raw material changes according to the actual content of this comparative example, everything else is the same as in Example 1.

[0068] The weight percentages of component A include: 31.33% epoxy resin, 6.27% toughening resin, 10.74% solvent, 21.49% polyphosphate amine, 7.16% pentaerythritol, 7.16% melamine, 6.00% graphene oxide, 5.37% organic flame retardant, 1.79% inorganic flame retardant, and 2.69% additive.

[0069] The weight percentages of component B include: 52.22% epoxy curing agent and 47.78% solvent.

[0070] In the above embodiments and comparative examples, tinplate was used as the experimental object, and the test conditions were 85°C and 85% humidity for 168 hours, after which the thermal insulation efficiency attenuation was detected to highlight the gain effect of the conventional heat dissipation and water treatment of the present application over the conventional expansion fire retardant coating. The experimental results of the thermal insulation efficiency attenuation were tested in accordance with the national standard GB14907-2018 "Steel Structure Fire Retardant Coating".

[0071] In GB14907-2018 "Steel Structure Fire Retardant Coatings", the thermal insulation efficiency attenuation of steel structure fire retardant coatings is calculated using the following formula: θ = (T0-T) / T0×100% Where: θ- thermal insulation efficiency attenuation, %; T0-benchmark thermal insulation efficiency, in minutes (min); T-Insulation efficiency of the large specimen after the durability test, in minutes (min).

[0072] When T≥T0, it means that the thermal insulation efficiency of the specimen has not decayed.

[0073]

[0074] From the above table we can know that: 1. There is not much difference in thermal insulation efficiency between the embodiments and the comparative examples, and they can be used as a basis for comparison.

[0075] 2. It can be seen from Example 1, Example 2, Example 3, Example 4, Comparative Example 1, and Comparative Example 2 that the addition of graphene oxide greatly improves the heat dissipation effect; however, due to the graphene flake structure, the paint film strength can be increased and the gas barrier function can be achieved, so the addition of graphene will reduce the expansion coefficient. In Comparative Example 2, the expansion coefficient is less than 300%, which proves that the amount of graphene added is excessive.

[0076] 3. It can be seen from Example 3 and Comparative Example 3 that Example 3 using melamine-coated ammonium polyphosphate and modified pentaerythritol replaces Comparative Example 3 of ammonium polyphosphate and pentaerythritol. After being treated with double 85, the thermal insulation efficiency attenuation of Example 3 is small, the water resistance is improved, and a safer scenario for preventing power battery explosion is provided.

[0077] 4. Embodiment 3 is preferred from the embodiments and comparative examples. Embodiment 3 has good heat dissipation capability and good thermal expansion capability. In a humid environment, the thermal insulation attenuation is low. Therefore, Embodiment 3 can improve the heat dissipation capability of the power battery during charging and reduce the probability of thermal runaway due to heat accumulation during the charging process. At the same time, compared with conventional expansion flame retardant coatings, it is safer and its performance is maintained longer. In automotive application scenarios, water and water vapor are often encountered. The present application is not easily affected by water and water vapor, which improves the safety of application in harsh scenarios.

[0078] The implementation principles of a flame retardant coating, a preparation method of the flame retardant coating, and a use method of the flame retardant coating in this embodiment are as follows: By adding graphene oxide, the flame retardant coating has good thermal conductivity, which can improve the heat dissipation capacity of the power battery during charging and reduce the probability of thermal runaway caused by heat accumulation during charging. The addition ratio of graphene oxide in component A is 0-10.00%, so that the flame retardant coating can still maintain a good expansion effect. By using coated polyphosphate amine and modified pentaerythritol, the thermal insulation efficiency of the flame retardant material is less attenuated in a high temperature and humid environment, which improves the safety of application in harsh scenarios.

[0079] The above are all preferred embodiments of the present invention, and are not intended to limit the protection scope of the present invention. Therefore, any equivalent changes made based on the structure, shape, and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A flame retardant coating, characterized in that: The weight percentage of the composition includes: component A and component B, The weight percentage of component A includes: epoxy resin 29.95-35.00%, toughening resin 5.99-7.00%, solvent 9.00-11.45%, coated polyphosphate amine 19.64-24.00%, modified pentaerythritol 6.55-8.00%, melamine 6.55-8.00%, graphene oxide 0-10.00%, organic flame retardant 4.91-6.00%, inorganic flame retardant 1.64-2.00%, additive 1.00-4.91%; The weight percentages of component B include: 47.76-58.30% of epoxy curing agent and 41.70-52.24% of solvent.

2. A flame retardant coating according to claim 1, characterized in that: The modified pentaerythritol is prepared by the following steps: 1 mol of melamine, 2.5 mol of paraformaldehyde and 1 L of deionized water were added to a 2 L three-necked flask equipped with a reflux condenser, a stirrer and a thermometer, and the pH value of the material was adjusted to 9 with a 10% sodium hydroxide solution, and then the temperature was raised to 75°C for reaction for 1 hour, and then the temperature of the material was lowered to 55°C, and 4.5 mol of pentaerythritol was added, and the pH value of the material was adjusted to 1.5 with a 20% hydrochloric acid, and the reaction was carried out at 55±5°C for 2.5 hours, and then the temperature was raised to 80±5°C for further reaction for 2 hours. After the reaction, the pH value of the material was adjusted to 9 with a 10% sodium hydroxide solution, and the material was cooled to room temperature, filtered with a filter cake, and the filter cake was washed with deionized water. The filter cake was dried at 150°C for 3 hours to obtain a modified pentaerythritol product.

3. A flame retardant coating according to claim 2, characterized in that: The ratio of the coated polyphosphate amine, modified pentaerythritol and melamine is 3:1:

1.

4. A method for preparing component A as claimed in any one of claims 1 to 3, characterized in that: The following steps are involved: a. Weigh epoxy resin, toughening resin, coated polyphosphate amine, modified pentaerythritol, melamine, graphene oxide, organic flame retardant, inorganic flame retardant and additives according to the proportion of each substance in component A of the flame retardant coating according to any one of claims 1 to 3; b. Add epoxy resin, toughening resin and solvent into a stirring tank, stir at a speed of 500-700 r / min, and add coated polyphosphate amine, modified pentaerythritol, melamine, graphene oxide, organic flame retardant, inorganic flame retardant and additives during stirring; c. Continue stirring at a speed of 1500-2000 r / min and take samples continuously until the fineness is less than 20 μm as tested by a scraper fineness meter; d. Filter with 200-mesh filter cloth and package.

5. A method for preparing component B as claimed in any one of claims 1 to 3, characterized in that: The following steps are involved: e. Weigh the epoxy curing agent and the solvent according to the proportion of each substance of component B in the flame retardant coating according to any one of claims 1 to 3; f. Add epoxy curing agent and solvent into the stirring tank at a stirring speed of 800-1000 r / min until the epoxy curing agent is completely dissolved; g. Filter through a 300-mesh filter and repackage.

6. A method for using the flame retardant coating according to any one of claims 1 to 3, characterized in that: The following steps are involved: h. Wipe the surface of the object to be coated with alcohol, and then treat the surface of the object to be coated with a coupling agent to remove all kinds of oil and dust on the surface of the object to be coated; i. Mix component A and component B in a mass ratio of 1:0.3; Spray it on the workpiece with a high-pressure spray gun, the coating thickness is between 2 and 3 mm, and cure at room temperature for 48 hours.

7. A method of use according to claim 6, characterized in that: In the step i, three sprayings are carried out, and the total thickness after three sprayings is between 2 and 3 mm. After the first spraying and the second spraying, they are cured at room temperature for 24 hours, and after the third spraying, they are cured at room temperature for 48 hours.

8. A product using a flame retardant coating, characterized in that: The product is coated with the coating film as claimed in claim 6 or 7.

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