Micro-expansion insulating flame-retardant coating for ultra-thin coating, preparation method and application thereof

Abstract

The application discloses a micro-expansion insulating fire-retardant coating capable of being used for ultrathin coating, and a preparation method and application thereof. Raw materials for forming the coating contain the following components in parts by mass: 15-45 parts of film-forming resin, 0.5-30 parts of fire retardant, 5-40 parts of high-temperature-resistant filler, and 5-30 parts of solvent. The fire-retardant coating is simple in construction, high in stability, good in electric insulation performance, excellent in fire-retardant and heat-insulating performance, and capable of being used for light and thin coating, and can well solve the problems in the field of fire-retardant coatings for new energy automobile batteries.

Description

Technical Field

[0001] This invention relates to the field of flame-retardant coatings for batteries. More specifically, it relates to a micro-expansion insulating and heat-insulating flame-retardant coating that can be used for ultra-thin coatings, its preparation method, and its application. Background Technology

[0002] Currently, the power systems of new energy vehicles mainly rely on lithium-ion batteries. After years of development, the performance of lithium-ion batteries has been significantly improved, but under certain conditions, the risk of combustion and explosion still exists. Accidents involving fires and explosions in electric vehicles caused by the "thermal runaway" of power batteries are also common.

[0003] To improve the thermal safety of lithium-ion batteries, new materials with insulation, flame retardancy, and heat insulation functions are widely used in lithium-ion battery cells, modules, and systems. Examples include flame-retardant plastic foam, mica boards, aerogel felt pads, composite ceramic fiber cotton, ceramicized silicone pads, polyurethane foam, silicone foam, and flame-retardant coatings. Among these, flame-retardant coatings are functional materials that effectively delay the spread of fire, improve the fire resistance limit of the substrate, and are easy to apply. Of the various flame-retardant coatings, intumescent flame-retardant coatings are widely used in building structure fire protection due to their excellent heat insulation and fireproofing effects. After the intumescent flame-retardant coating forms a film, it expands under open flame or high temperature, rapidly forming a porous expanded char layer. This char layer effectively reduces the thermal conductivity, isolates oxygen, and protects the substrate. It is understood that the dry film thickness of currently mass-produced flame-retardant coatings generally needs to be 0.5mm or even 1mm or more to achieve good flame-retardant and heat-insulating effects. However, large-area thick coatings (dry film ≥ 0.5mm) not only have a complicated construction process but are also prone to problems such as dry film cracking. In addition, the carbon layer formed after the coating expands has a porous structure. Due to uneven heating and space constraints, it is prone to problems such as poor mechanical strength, large differences in the performance of the carbon layer in different areas, and poor insulation performance of the carbon layer after combustion.

[0004] Thermal runaway in power batteries begins with the decomposition of the SEI film at the negative electrode, followed by the melting of the separator, a reaction between the negative electrode and the electrolyte, and subsequently, the decomposition of both the positive electrode and the electrolyte. The electrolyte decomposition generates a large amount of gas, and heat rapidly dissipates and spreads to other cells. During this process, the cell temperature rises sharply, and open flames containing gas are ejected from the explosion-proof valve. If ordinary intumescent flame-retardant coatings are used to protect the PACK cover, the coating will quickly peel off under high temperature and pressure, losing its protective function, and secondary damage may occur due to the poor insulation performance of the carbon layer. Furthermore, ordinary intumescent flame-retardant coatings require a relatively thick dry film and have a large expansion ratio after heating, often exceeding 10 times, to achieve good results. These requirements contradict the lightweight development trend of new energy vehicles. Additionally, as the demand for longer driving ranges in new energy vehicles increases, related materials need to be developed towards lightweight design.

[0005] For the reasons mentioned above, there is an urgent need to develop a lightweight flame-retardant coating that is easy to apply, highly stable, has good electrical insulation properties, and excellent flame-retardant and heat-insulating properties, in order to at least solve the problems faced in the field of existing flame-retardant coatings for new energy vehicle batteries. Summary of the Invention

[0006] Based on the above facts, the purpose of this invention is to provide a micro-expansion insulating, heat-insulating, and flame-retardant coating suitable for ultra-thin coatings, its preparation method, and its application. This flame-retardant coating is simple to apply, highly stable, has good electrical insulation properties, excellent flame-retardant and heat-insulating properties, and can be used for thin-film coatings, effectively solving the problems faced in the field of existing flame-retardant coatings for new energy vehicle batteries.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] A micro-expansion insulating, heat-insulating, and flame-retardant coating suitable for ultra-thin coatings, wherein the raw materials forming the coating comprise, by weight, the following components:

[0009] 15-45 parts of film-forming resin;

[0010] Flame retardant 0.5-30 parts;

[0011] Pigments and fillers, including 5-40 parts of high-temperature resistant filler; and

[0012] Solvent 5-30 parts.

[0013] Furthermore, the film-forming resin is selected from epoxy resin and / or modified epoxy resin, and

[0014] The epoxy resin and / or modified epoxy resin have an epoxy equivalent of 150-250 g / eq and a viscosity of 300-2500 cps at 25°C.

[0015] Furthermore, the modified epoxy resin is selected from at least one of polyurethane modified epoxy resin, acrylate modified epoxy resin, polyester modified epoxy resin, silicone modified epoxy resin, and phenolic modified epoxy resin.

[0016] Furthermore, the epoxy resin is selected from one or more of bisphenol A type epoxy resin, bisphenol F type epoxy resin, and epichlorohydrin epoxy resin.

[0017] Furthermore, the flame retardant is selected from one or more of organophosphonate flame retardants, phosphate flame retardants, and modified phosphate flame retardants.

[0018] Furthermore, the organophosphonate flame retardant is selected from one or more of phosphate esters, phosphites, and phosphate esters.

[0019] Furthermore, the phosphate flame retardant is selected from one or more of zinc phosphate, aluminum phosphate, ammonium pyrophosphate, diammonium hydrogen phosphate, and ammonium polyphosphate.

[0020] Furthermore, the modified phosphate flame retardant is selected from at least one of silane coupling agents, melamine, melamine resin, phenolic resin, and epoxy resin to modify the phosphate flame retardant.

[0021] Furthermore, the raw materials also contain 0-30 parts of flame retardant.

[0022] Furthermore, the flame retardant is selected from one or more of melamine, melamine resin, melamine phosphate, and melamine cyanurate.

[0023] Furthermore, the mass ratio of the flame retardant to the flame retardant co-antifact is 3:1-5:1.

[0024] Furthermore, in the raw materials, the pigment-to-binder ratio is 0.5:1-4:1.

[0025] Furthermore, in the raw materials, the pigment-to-binder ratio is 1:1 to 3:1.

[0026] Furthermore, the pigments and fillers also include 0-30 parts of heat-insulating filler and 0-20 parts of pigment.

[0027] Furthermore, the heat-insulating filler is selected from one or more of hollow glass microspheres, hollow ceramic microspheres, porous silica, porous carbon, porous silicon carbide, and porous metal oxides.

[0028] Furthermore, the raw material also contains additives, including 0.05-10 parts of dispersant, 0.5-10 parts of defoamer, 5-20 parts of crosslinking agent and 0-10 parts of rheology modifier.

[0029] In another aspect, the present invention provides a method for preparing the micro-expansion insulating, heat-insulating, and flame-retardant coating as described above, the method comprising the following steps:

[0030] Mix all the raw material components evenly and grind them until the fineness of the resulting mixture is ≤100μm.

[0031] In another aspect, the present invention provides the application of the micro-expansion insulating, heat-insulating, and flame-retardant coating described above in the coating of batteries.

[0032] Furthermore, the battery is a lithium-ion battery.

[0033] Furthermore, the coating is an ultra-thin coating.

[0034] The beneficial effects of this invention are as follows:

[0035] The micro-expansion insulating, heat-insulating, and flame-retardant coating provided by this invention, which can be used for ultra-thin coatings, achieves high stability and workability by controlling the selection and dosage of film-forming resin, flame-retardant system, pigments, fillers, and other preferred additives in its raw materials. This makes it suitable for ultra-thin coatings on batteries. Furthermore, this solution effectively solves the problems of high dry film thickness, low stability of the expanded carbon layer, poor mechanical strength, and poor insulation performance associated with intumescent flame-retardant coatings used on batteries. Detailed Implementation

[0036] To more clearly illustrate the present invention, the following description, in conjunction with preferred embodiments, further clarifies the invention. Those skilled in the art should understand that the specific descriptions below are illustrative rather than restrictive, and should not be construed as limiting the scope of protection of the present invention.

[0037] In some technical solutions, to achieve good flame-retardant and heat-insulating effects, the dry film thickness of flame-retardant coatings for lithium-ion batteries needs to be controlled at 0.5 mm or even more than 1 mm. However, large-area thick coatings (dry film ≥ 0.5 mm) are prone to dry film cracking. Furthermore, the flame-retardant coatings formed by lithium-ion battery flame-retardant coatings are prone to problems such as poor mechanical strength after combustion and poor insulation performance due to the porous structure of the char layer after combustion. These shortcomings prevent the coating from providing good protection under high temperature and high pressure conditions. To address these problems, a specific embodiment of the present invention provides a micro-expansion insulating and heat-insulating flame-retardant coating that can be used for ultra-thin coatings. The raw materials forming the coating, by weight, contain the following components:

[0038] 15-45 parts of film-forming resin;

[0039] Flame retardant 0.5-30 parts;

[0040] Pigments and fillers, including 5-40 parts of high-temperature resistant filler; and

[0041] Solvent 5-30 parts.

[0042] In this embodiment, the provided coating can be used for coating batteries (such as lithium-ion batteries), especially for ultra-thin coatings of batteries. Specifically, the coating for batteries can be a thick coating, a thin coating, or an ultra-thin coating, and the dry film thickness of the resulting coating can be greater than or less than 0.5 mm (more specifically, less than 0.5 mm and greater than or less than 0.1 mm, or less than 0.1 mm). Here, "ultra-thin coating" as mentioned above refers to a dry film thickness of less than 0.5 mm. Through this embodiment, ultra-thin coatings of less than 0.2 mm can be achieved.

[0043] In some examples, the film-forming resin is selected from epoxy resins and / or modified epoxy resins, and

[0044] The epoxy resin and / or modified epoxy resin have an epoxy equivalent of 150-250 g / eq and a viscosity of 300-2500 cps at 25°C.

[0045] When used as a film-forming resin, the aforementioned epoxy resin and / or modified epoxy resin exhibit excellent mechanical properties, adhesion, good thermal stability, electrical insulation, weather resistance, and chemical resistance. Furthermore, the film-forming resin possesses certain functional groups, enabling it to form chemical bonds with the substrate and improve adhesion. Additionally, the film-forming resin system has a low viscosity, facilitating the preparation of high pigment-to-binder ratio systems. Moreover, flame-retardant coatings containing this film-forming resin exhibit a high char residue rate during combustion tests.

[0046] In some specific examples, the modified epoxy resin used in this embodiment is selected from at least one of polyurethane modified epoxy resin, acrylate modified epoxy resin, polyester modified epoxy resin, silicone modified epoxy resin, and phenolic modified epoxy resin.

[0047] Exemplary amounts of film-forming resin include, but are not limited to, 15-35 parts, 15-30 parts, 15-25 parts, 15-24 parts, 15-20 parts, 20-30 parts, 20-25 parts, 20-24 parts, 24-30 parts, 20 parts, 24 parts, 30 parts, etc.

[0048] The epoxy resins applicable to this embodiment include, but are not limited to, one or more of bisphenol A type epoxy resin, bisphenol F type epoxy resin and epichlorohydrin epoxy resin.

[0049] In flame-retardant coatings, the selection of flame retardants requires consideration not only of their own performance but also of their compatibility with film-forming resins and the overall formulation. The flame retardants suitable for this implementation scheme are selected from one or more of organophosphonate flame retardants, phosphate flame retardants, and modified phosphate flame retardants.

[0050] For example, the organophosphonate flame retardant is selected from one or more of phosphate esters, phosphites, and phosphate esters.

[0051] For example, the phosphate flame retardant is selected from one or more of zinc phosphate, aluminum phosphate, ammonium pyrophosphate, diammonium hydrogen phosphate, and ammonium polyphosphate.

[0052] For example, the modified phosphate flame retardant is selected from those obtained by modifying phosphate flame retardants with at least one of silane coupling agents, melamine, melamine resin, phenolic resin, and epoxy resin. The resulting products include, but are not limited to: silane coupling agent-modified ammonium polyphosphate, melamine-modified ammonium polyphosphate, melamine resin-modified polyphosphate, epoxy resin-modified ammonium polyphosphate, and phenolic resin-modified ammonium polyphosphate. These modification methods can be conventional modification methods in the flame retardant field (e.g., coating), and will not be elaborated here.

[0053] In some specific examples, the amount of flame retardant added includes, but is not limited to, 5-20 parts, 5-15 parts, 5-10 parts, 10-20 parts, 10-15 parts, 15-20 parts, 15 parts, 10 parts, etc.

[0054] By using the aforementioned flame retardant, the resulting flame-retardant coating can still maintain good flame-retardant performance even when applied in an ultra-thin coating.

[0055] In some examples, the raw materials also contain flame retardants. Suitable flame retardants may be one or more of melamine, melamine resin, melamine phosphate, and melamine cyanurate. These flame retardants can synergistically enhance flame retardancy, improve flame retardant efficiency, and control the expansion ratio of the coating, ensuring that while achieving ultra-thin coating of lithium-ion batteries, the coating also possesses good structural stability, flame retardancy, and insulation properties.

[0056] In some examples, the raw material also contains 0-30 parts of flame retardant. The flame retardant in the raw material may include, but is not limited to, 0 parts, 1-30 parts, 1-10 parts, 1-5 parts, 1-2 parts, 2-10 parts, 2-5 parts, 2 parts, 5 parts, etc.

[0057] In some preferred examples, the mass ratio of the flame retardant to the flame retardant co-ant is 3:1 to 5:1. In this case, the synergistic effect of the two in flame retardancy and controlling the expansion ratio of the coating is even better.

[0058] In some preferred examples, the pigment-to-binder ratio in the raw materials is 0.5:1-4:1. If the pigment-to-binder ratio is too low, the resulting coating will have poor flame retardancy; if the pigment-to-binder ratio is too high, the coating will have poor adhesion to the substrate, and its insulation and durability will also deteriorate. Exemplary pigment-to-binder ratios include, but are not limited to, 1:1-3:1, 1.2:1-3:1, 1.2:1-2.6:1, 1.2:1-2.5:1, 1.4:1-2.6:1, 1.4:1-2.5:1, 1.4:1-2.1:1, 2:1-2.5:1, 1.46:1-2.5:1, 1.46:1, 2.02:1, and 2.5:1.

[0059] It should be noted that the "pigment-to-binder ratio" in this embodiment refers to the ratio of the total mass of solid materials added to the coating raw material to the mass of the film-forming resin. For example, the pigment-to-binder ratio in this embodiment refers to the ratio of the total mass of flame retardant, high-temperature resistant filler, flame retardant aid (if any), heat-insulating filler (if any), and pigment (if any) in the coating raw material to the mass of the film-forming resin.

[0060] In the pigments and fillers of the coating raw materials provided in this embodiment, heat-insulating fillers and / or pigments may be added as needed.

[0061] Exemplary thermal insulation fillers include, but are not limited to, one or more selected from hollow glass microspheres, hollow ceramic microspheres, porous silica, porous carbon, porous silicon carbide, and porous metal oxides (e.g., porous alumina, porous magnesium oxide, porous zirconium oxide, porous titanium dioxide, etc.). The amount of thermal insulation filler used can be 0-30 parts. Exemplary amounts include, but are not limited to, 0 parts, 2-20 parts, 2-15 parts, 5-14 parts, 5-12.5 parts, 12.5-14 parts, 5 parts, 12.5 parts, 14 parts, etc.

[0062] In this embodiment, the pigment is a conventional organic pigment and / or inorganic pigment. For example, white pigment, black pigment, etc. An exemplary black pigment may be an inorganic pigment with certain high-temperature resistance properties, such as one or more of iron-manganese black, iron oxide black, graphite, etc. An exemplary white pigment may be one or more of titanium dioxide, zinc oxide, zinc sulfide, barium sulfate, etc.

[0063] In this embodiment, the exemplary amount of pigment used can be 0-20 parts. Specifically, it can include, but is not limited to, 0 parts, 1-10 parts, 1-5 parts, 5 parts, etc.

[0064] In some examples, the high-temperature resistant filler includes, but is not limited to, one or more of expanded perlite, vermiculite, bentonite, wollastonite, kaolin, clay, mica powder, feldspar powder, calcium carbonate, sepiolite, boehmite, zirconium oxide, and yttrium-stabilized zirconium oxide, boron nitride, boron carbide, and aluminum nitride. The exemplary amounts of the high-temperature resistant filler added to the raw materials include, but are not limited to, 5-30 parts, 5-25 parts, 5-24 parts, and 24-30 parts.

[0065] In this embodiment, the solvent is selected from one or more of butyl acetate, N-methylpyrrolidone, and propylene glycol methyl ether acetate. Exemplary solvent addition amounts include, but are not limited to, 5-20 parts, 5-15 parts, 5-10 parts, 10-20 parts, 10-15 parts, 10-12 parts, 12-20 parts, 12-15 parts, 15-20 parts, 15 parts, 12 parts, and 10 parts.

[0066] In some examples, the total weight of the raw materials described in this embodiment is 100 parts.

[0067] In this embodiment, by selecting suitable film-forming resins, high-efficiency flame retardants, high-temperature resistant fillers, and heat-insulating fillers, a balance between micro-expansion ratio and coating strength after combustion is achieved.

[0068] The coating provided in this embodiment may also contain additives, depending on actual needs. Examples include dispersants, defoamers, crosslinking agents, and rheology modifiers.

[0069] The dispersant is preferably one or more of low-molecular-weight and high-molecular-weight modified polymers that have certain anchoring groups and can interact with flame retardants, flame retardant co-applicants, high-temperature resistant fillers, heat-insulating fillers, etc. in the system to achieve wetting, dispersion and anti-settling effects, and are soluble in organic solvents. The content of the dispersant in the additives includes, but is not limited to, 0.05-10 parts, 1-5 parts, 1-3 parts, 1-2.5 parts, 1-2 parts, 2-5 parts, 2-3 parts, 2-2.5 parts, 2.5-3 parts, 2 parts, 2.5 parts, and 3 parts. Applicable dispersants include, but are not limited to, BYK-2012 and BYK-220. Preferably, BYK-220 and BYK-2012 are mixed in a mass ratio of 1:1 to 1:3.

[0070] Defoamers suitable for this embodiment include, but are not limited to, one or more of mineral oils, organosilicon compounds, and polymers. The content of the defoamer in the additive includes, but is not limited to, 0.05-10 parts, 1-5 parts, 1-2 parts, 1-1.5 parts, 1.5-2 parts, 1 part, 1.5 parts, 2 parts, etc. Applicable defoamers include, but are not limited to, BYK-1799. Airex 920, etc.

[0071] The crosslinking agent suitable for this embodiment can be one or more of the following: low-viscosity modified aliphatic diammonium phosphate, polyamines, aromatic polyamines, and modified alicyclic amines. It can be cured at room temperature or the curing process can be accelerated by heating. The amine value is typically between 50-350 mg KOH / g. The content of the crosslinking agent in the additive includes, but is not limited to, 5-20 parts, 5-15 parts, 5-12 parts, 5-12 parts, 8-12 parts, 8-10 parts, 10-12 parts, 8 parts, 10 parts, and 12 parts. Curing agents such as DOWD.EH530 and DEH125 can be selected. In some preferred examples, the mass ratio of the film-forming resin to the crosslinking agent is 1.5:1-3:1. In this case, the hardness of the coating film is suitable, and it has improved adhesion to the substrate and resistance to high and low temperature cycling. As a further example, the mass ratio of the film-forming resin to the crosslinking agent includes, but is not limited to, 2:1-3:1, 2.4:1-3:1, 2.4:1-2.5:1, 2.4:1, 2.5:1, etc.

[0072] The rheology modifier suitable for this embodiment may be one or more of organobentonite, montmorillonite, fumed silica, etc. The content of the rheology modifier in the modifier includes, but is not limited to, 0-10 parts, 0 parts, 1-10 parts, 1-2 parts, 1-1.5 parts, 1.5-2 parts, 1 part, 1.5 parts, 2 parts, etc.

[0073] In some specific examples, the additives contain 0.05-10 parts of dispersant, 0.5-10 parts of defoamer, 5-20 parts of crosslinking agent and 0-10 parts of rheology modifier.

[0074] According to another specific embodiment of the present invention, a method for preparing the micro-expansion insulating, heat-insulating, and flame-retardant coating as described above is provided, the method comprising the following steps:

[0075] Mix all the raw material components evenly and grind them until the fineness of the resulting mixture is ≤100μm.

[0076] In some more specific examples, the preparation method includes the following steps:

[0077] At room temperature, mix the raw materials of each component at a speed of 100-4000 r / min until homogeneous;

[0078] The above-mentioned uniformly mixed solution is placed in a high-speed stirring tank containing zirconium beads and dispersed at a speed of 100-4000 r / min for 30-180 min. The mixture is then filtered through a 150-mesh filter to ensure that the fineness of the resulting solution is ≤100 μm.

[0079] According to another specific embodiment of the present invention, the application of the micro-expansion insulating, heat-insulating, and flame-retardant coating as described above in the coating of batteries is provided.

[0080] In some examples, the coating is preferably used for coating batteries for new energy vehicles.

[0081] In some examples, the battery is a lithium-ion battery.

[0082] In some examples, the coating is, but is not limited to, an ultra-thin coating.

[0083] In some examples, the painting location includes, but is not limited to, the battery pack.

[0084] In some specific examples, the application involves coating the battery with the micro-expansion insulating, heat-insulating, and flame-retardant coating to form a coating layer. Specific coating methods include, but are not limited to:

[0085] Apply the coating to the surface of the battery to be coated (preferably after sanding and degreasing before use), and cure at room temperature for more than 24 hours or dry at 60-80℃ for more than 2 hours.

[0086] The above-mentioned application methods include, but are not limited to, spraying (such as air spraying), scraping, and brushing.

[0087] Before applying the above coating to the surface of the battery to be coated, it can be determined whether to use a thinner (butyl acetate, propylene glycol methyl ether acetate, etc.) based on the flow of the mixture. Usually, the mass ratio of the mixture to the thinner is 1:0-1:0.5. Based on the coating thickness, determine the appropriate spraying parameters and carry out the spraying.

[0088] The specific embodiments of the present invention will be described below with reference to some specific examples:

[0089] Example 1

[0090] A micro-expansion insulating, heat-insulating, and flame-retardant coating suitable for ultra-thin coating applications is prepared by the following steps:

[0091] Based on a feed rate of 100 kg, 10 kg of propylene glycol methyl ether acetate, 30 kg of silicone-modified epoxy resin, 15 kg of ammonium polyphosphate, 5 kg of melamine, 5 kg of mica powder, 4 kg of hollow glass microspheres, 10 kg of hollow ceramic microspheres, 0.5 kg of BYK-220, 1.5 kg of BYK-2012, 1 kg of BYK-1799, 12 kg of DOW DEH530, 1 kg of organic bentonite, and 5 kg of titanium dioxide are mixed evenly at a high speed of 100-4000 r / min, and then ground in a sand mill at a speed of 100-4000 r / min for 60-180 min. Finally, the mixture is filtered through 150-mesh filter paper to obtain the micro-expansion insulating, heat-insulating, and flame-retardant coating.

[0092] The micro-expansion insulating, heat-insulating, and flame-retardant coating was applied by spraying onto a steel plate with an epoxy electrophoretic layer or a new nickel electroplating layer with a thickness of 0.8 mm. The drying temperature was 60-80℃ and the drying time was >2 hours, resulting in a white coating with a smooth appearance and a dry film thickness of 150±50 μm.

[0093] Example 2

[0094] A micro-expansion insulating, heat-insulating, and flame-retardant coating suitable for ultra-thin coating applications is prepared by the following steps:

[0095] Based on a feed rate of 100 kg, 12 kg of N-methylpyrrolidone, 24 kg of polyurethane-modified epoxy resin, 10 kg of phenolic resin-modified ammonium polyphosphate, 2 kg of melamine cyanurate, 8 kg each of feldspar powder, mica powder, and boehmite, 6.5 kg of hollow ceramic microspheres, 6 kg of porous alumina, 1 kg of BYK-220, 1.5 kg of BYK-2012, 1.5 kg of BYK-1799, 10 kg of DOWD.EH530, and 1.5 kg of fumed silica are mixed at a high speed of 100-4000 r / min until homogeneous. The mixture is then ground in a sand mill at a speed of 100-4000 r / min for 60-180 min. Finally, it is filtered through 150-mesh filter paper to obtain the micro-expansion insulating, heat-insulating, and flame-retardant coating.

[0096] The micro-expansion insulating, heat-insulating, and flame-retardant coating is applied by spraying onto a steel plate with an epoxy electrophoretic layer or a new nickel electroplating layer with a thickness of 0.8 mm. The drying temperature is 60-80℃ and the drying time is >2h, resulting in a nearly transparent coating with a smooth appearance and a dry film thickness of 150±50μm.

[0097] Example 3

[0098] A micro-expansion insulating, heat-insulating, and flame-retardant coating suitable for ultra-thin coating applications is prepared by the following steps:

[0099] Based on a feed rate of 100 kg, 10 kg of propylene glycol methyl ether acetate, 5 kg of N-methylpyrrolidone, 20 kg of acrylate-modified epoxy resin, 10 kg of melamine-modified ammonium polyphosphate, 6 kg each of mica powder, wollastonite powder, calcium carbonate, kaolin, and aluminum nitride, 5 kg of hollow ceramic microspheres, 1 kg of BYK-220, 2 kg of BYK-2012, 2 kg of BYK-1799, 8 kg of DOW DEH530, 2 kg of fumed silica, and 5 kg of iron oxide are mixed at a high speed of 100-4000 r / min until uniform. The mixture is then ground in a sand mill at a speed of 100-4000 r / min for 60-180 min. Finally, it is filtered through 150-mesh filter paper to obtain the micro-expansion insulating, heat-insulating, and flame-retardant coating.

[0100] The micro-expansion insulating, heat-insulating, and flame-retardant coating was applied by spraying onto a steel plate with an epoxy electrophoretic layer or a new nickel electroplating layer with a thickness of 0.8 mm. The drying temperature was 60-80℃ and the drying time was >2 hours, resulting in a black coating with a smooth appearance and a dry film thickness of 150±50 μm.

[0101] The properties of the products prepared in the above embodiments are shown in Table 1 below.

[0102] Performance testing conditions:

[0103] 1) Adhesion test: The paint film was subjected to a cross-cut adhesion test in accordance with the national standard GB / T9286-2021;

[0104] 2) Hardness test: The pencil hardness of the paint film was tested according to the national standard GB / T 6739-2006;

[0105] 3) Fire resistance test: Select a specific gas source that can reach 1000-1300℃ according to customer needs to conduct fire resistance test. During the combustion test, attach a thermocouple to the back of the substrate and test and record the temperature of the uncoated surface during the 30-minute combustion process. There is no specific national standard, but the whole package test must meet GB 38031-2020.

[0106] 4) Insulation withstand voltage test: The insulation withstand voltage of the varnish film shall be tested in accordance with the national standard GB / T 1408.1-2016;

[0107] 5) Water resistance test, damp heat resistance test and high and low temperature alternation test: The samples were tested for water resistance, damp heat resistance and high and low temperature alternation test according to GB 38031-2020.

[0108] Table 1 Product Parameters of Examples

[0109]

[0110] Comparative Example 1

[0111] An insulating, heat-insulating, and flame-retardant coating is prepared by the following steps:

[0112] Based on a 100kg feed rate, the following components are used: 7kg propylene glycol methyl ether acetate, 25kg polyurethane modified epoxy resin, 15kg ammonium polyphosphate, 5kg melamine, 5kg mica powder, 4kg hollow glass microspheres, 10kg hollow ceramic microspheres, 0.5kg BYK-220, 1.5kg BYK-2012, 1kg BYK-1799, 20kg DOW DEH530, 1kg organic bentonite, and 5kg titanium dioxide. These are mixed uniformly at a high speed of 100-4000 rpm, and then ground in a sand mill at 100-4000 rpm for 60-180 minutes. The mixture is then filtered through 150-mesh filter paper to obtain the micro-expansion insulating, heat-insulating, and flame-retardant coating.

[0113] The product was sprayed onto a steel plate with an epoxy electrophoretic layer or a new nickel electroplating layer with a thickness of 0.8 mm. The drying temperature was 60-80℃ and the drying time was >2h, resulting in a black sample with a smooth appearance and a dry film thickness of 150±50μm.

[0114] It should be noted that, due to the excessive amount of crosslinking agent relative to film-forming resin in this comparative example, the dry film of the coating has a high hardness, poor adhesion to the substrate, and poor resistance to high and low temperature cycling.

[0115] Comparative Example 2

[0116] An insulating, heat-insulating, and flame-retardant coating is prepared by the following steps:

[0117] Based on a 100kg feed rate, the following components are used: 5kg N-methylpyrrolidone, 50kg silicone-modified epoxy resin, 10kg phenolic resin-modified ammonium polyphosphate, 2kg each of feldspar powder, mica powder, and boehmite, 2kg hollow ceramic microspheres, 0.2kg BYK-220, 0.3kg BYK-2012, 0.5kg BYK-1799, 25kg DOW DEH530, and 1kg fumed silica. These are mixed uniformly at a high speed of 100-4000 rpm, and then ground in a sand mill at 100-4000 rpm for 60-180 minutes. The mixture is then filtered through 150-mesh filter paper to obtain the micro-expansion insulating, heat-insulating, and flame-retardant coating.

[0118] The product was sprayed onto a steel plate with an epoxy electrophoretic layer or a new nickel electroplating layer with a thickness of 0.8 mm. The drying temperature was 60-80℃ and the drying time was >2h. A nearly transparent sample with a smooth appearance and a dry film thickness of 150±50μm was prepared.

[0119] It should be noted that the pigment content in this comparative example is relatively low, resulting in poor flame retardant and heat insulation performance of the sample.

[0120] Comparative Example 3

[0121] An insulating, heat-insulating, and flame-retardant coating is prepared by the following steps:

[0122] Based on a 100kg feed rate, the following components are used: 20kg propylene glycol methyl ether acetate, 12kg acrylate-modified epoxy resin, 20kg melamine-modified ammonium polyphosphate, 10kg melamine cyanurate, 3kg each of mica powder, wollastonite powder, calcium carbonate, kaolin, and aluminum nitride, 11kg hollow ceramic microspheres, 1kg BYK-220, 2kg BYK-2012, 2kg BYK-1799, 5kg DOWD.EH530, and 2kg fumed silica. These are mixed uniformly at a high speed of 100-4000 rpm, and then ground in a sand mill at 100-4000 rpm for 60-180 minutes. The mixture is then filtered through 150-mesh filter paper to obtain the micro-expansion insulating, heat-insulating, and flame-retardant coating.

[0123] The product was sprayed onto a steel plate with an epoxy electrophoretic layer or a new nickel electroplating layer with a thickness of 0.8 mm. The drying conditions were 60-80℃ and the drying time was >2h. A nearly transparent sample with a smooth appearance and a dry film thickness of 150±50μm was obtained.

[0124] It should be noted that in this comparative example, the pigment-to-binder ratio is relatively high, which leads to poorer adhesion of the dry film to the substrate, as well as a decrease in the insulation and durability of the dry film.

[0125] The properties of the products prepared in the above comparative examples are shown in Table 2 below.

[0126] Table 2 Comparative Product Parameters

[0127]

[0128]

[0129] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. For those skilled in the art, other variations or modifications can be made based on the above description. It is impossible to exhaustively list all the implementation methods here. All obvious variations or modifications derived from the technical solutions of the present invention are still within the protection scope of the present invention.

Claims

1. A micro-expanding insulating flame retardant paint which can be used for ultra-thin coating, characterized in that, The raw materials for forming the coating include the following components, with the total amount of the raw materials being 100 kg: 10 kg of propylene glycol methyl ether acetate, 30 kg of silicone-modified epoxy resin, 15 kg of ammonium polyphosphate, 5 kg of melamine, 5 kg of mica powder, 4 kg of hollow glass microbeads, 10 kg of hollow ceramic microbeads, 0.5 kg of BYK-220, 1.5 kg of BYK-2012, 1 kg of BYK-1799, 12 kg of DOW D.E.H. 530, 1 kg of organic bentonite, and 5 kg of titanium white.

2. A micro-expanding insulating flame retardant paint which can be used for ultra-thin coating, characterized in that, The raw materials for forming the coating include the following components, with the total amount of the raw materials being 100 kg: 12 kg of N-methyl pyrrolidone, 24 kg of polyurethane-modified epoxy resin, 10 kg of phenolic resin-modified ammonium polyphosphate, 2 kg of melamine cyanurate, 8 kg of feldspar powder, 8 kg of mica powder, 8 kg of boehmite, 6.5 kg of hollow ceramic microbeads, 6 kg of porous alumina, 1 kg of BYK-220, 1.5 kg of BYK-2012, 1.5 kg of BYK-1799, 10 kg of DOW D.E.H. 530, and 1.5 kg of fumed silica.

3. Process for the preparation of microswelling insulating fire-retardant paints for ultra-thin application according to any one of claims 1-2, characterized in that, The method comprises the following steps: The components of the raw materials are uniformly mixed at a high speed of 100-4000 r / min, and are ground by a sand mill at a speed of 100-4000 r / min for 60-180 min, and then filtered by a 150-mesh filter paper to obtain the micro-expansion insulating and heat-insulating and flame-retardant coating.

4. The use of the micro-expansion insulating and heat-insulating and flame-retardant coating according to any one of claims 1-2 in the coating of a battery.

5. Use according to claim 4, characterized in that, The battery is a lithium ion battery. The coating is an ultrathin coating. The battery is a lithium ion battery. The coating is an ultrathin coating.

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