A fire-retardant coating for aerogel felt encapsulation and its preparation method

Abstract

This invention provides a fire-retardant coating for aerogel felt encapsulation and its preparation method. The fire-retardant coating comprises the following components in parts by weight: 30-50 parts water-based resin, 0-10 parts water-based colorant, 20-50 parts filler slurry, 8-30 parts flame retardant, 0-20 parts glass microspheres, 0.1-2 parts pH adjuster, 0.1-4 parts additives, and 0-20 parts water. This invention, by using a specific water-based resin and combining it with a specific flame retardant, can prepare a fire-retardant encapsulation coating for aerogel felt. Testing shows that its fire resistance rating can reach 4-5 levels, and its flexibility can achieve 180° bending without cracking.

Description

Technical Field

[0001] This invention relates to the field of coating technology, specifically to an encapsulation coating and its preparation method, and more particularly to a fire-retardant coating for aerogel felt encapsulation and its preparation method. Background Technology

[0002] With the rapid development of new energy vehicles, the safety of the power batteries used in them is receiving increasing attention, especially the risk of spontaneous combustion leading to high-temperature open flames. Aerogel felt is considered an ideal thermal insulation material for future new energy vehicle power batteries due to its excellent thermal insulation performance. However, it suffers from powder shedding; the volatile aerogel powder not only affects the thermal insulation properties of the aerogel felt but also seriously endangers human health. Therefore, encapsulation and protection are necessary to reduce the safety risks of the battery. Currently, most encapsulation materials are made of polymer materials, making it difficult to achieve fire-resistant performance. According to the draft for comments on "GB 38031 Safety Requirements for Power Batteries for Electric Vehicles," the battery pack or system should provide a thermal event alarm signal 5 minutes before thermal runaway of a single battery causes thermal diffusion and leads to danger in the passenger compartment. This places direct requirements on aerogel felt and aerogel encapsulation materials.

[0003] In previous research, the applicant team disclosed an environmentally friendly flame-retardant coating for aerogel encapsulation, prepared by combining a resin dispersion with high tensile strength and high elongation at break with filler slurry, flame retardant, and other additives. This coating exhibits a flame retardancy rating of UL94V0, flexibility to withstand 180° bending without cracking, and a shear strength exceeding 0.8 MPa (see patent document CN118029170A). However, this coating fails to meet fire resistance requirements. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide a fire-retardant coating for aerogel felt encapsulation and its preparation method.

[0005] The objective of this invention is achieved through the following technical solution:

[0006] In a first aspect, the present invention provides a fire-retardant coating for aerogel felt encapsulation, comprising the following components in parts by weight:

[0007]

[0008]

[0009] As a preferred embodiment, the aqueous resin includes at least one of ethylene vinyl acetate copolymer (EVA) emulsion, ethylene-co-acrylic acid copolymer (EAA) dispersion, and ethylene-co-methacrylic acid copolymer (EMAA) dispersion.

[0010] As a preferred embodiment, the aqueous resin is any one of ethylene vinyl acetate copolymer emulsion, ethylene-co-acrylic acid copolymer dispersion, and ethylene-co-methacrylic acid copolymer dispersion; or

[0011] The aqueous resin is a combination of an ethylene-co-acrylic acid copolymer dispersion and / or an ethylene-co-methacrylic acid copolymer dispersion and an ethylene vinyl acetate copolymer emulsion.

[0012] As a further preferred embodiment, the aqueous resin is a combination of an ethylene-co-acrylic acid copolymer dispersion and / or an ethylene-co-methacrylic acid copolymer dispersion and an ethylene vinyl acetate copolymer emulsion. Specifically, the aqueous resin is a combination of an ethylene-co-acrylic acid copolymer dispersion and an ethylene vinyl acetate copolymer emulsion, or a combination of an ethylene-co-acrylic acid copolymer dispersion, an ethylene-co-methacrylic acid copolymer dispersion, and an ethylene vinyl acetate copolymer emulsion.

[0013] As a preferred embodiment, the glass transition temperature (Tg) of the ethylene-vinyl acetate copolymer emulsion is below 20°C, and the molar ratio of ethylene to vinyl acetate is below 3:7. More preferably, the glass transition temperature (Tg) is 5°C or below, and the vinyl acetate ratio is between 3:7 and 1:9.

[0014] As a preferred embodiment, the ethylene-co-acrylic acid copolymer dispersion contains 1-10 wt% ethylene-co-acrylic acid copolymer, which can be specifically prepared by mixing ethylene-co-acrylic acid copolymer with water and NaOH in a mass ratio of 1-10:89-98:1.

[0015] As a preferred embodiment, the ethylene-co-methacrylic acid copolymer dispersion contains 1-2 wt% ethylene-co-methacrylic acid copolymer, which can be specifically prepared by mixing ethylene-co-methacrylic acid copolymer with water and NaOH in a ratio of 1-2:94-95:4.

[0016] As a preferred embodiment, the acrylic acid content in the ethylene-co-acrylic acid copolymer is greater than or equal to 20 wt%. Preliminary experiments of this invention revealed that if the acrylic acid content in the ethylene-co-acrylic acid copolymer is too low, it will be insoluble and therefore cannot be applied to the fire-retardant coating of this invention.

[0017] As a preferred embodiment, the methacrylic acid content in the ethylene-co-methacrylic acid copolymer is greater than or equal to 25 wt%. Preliminary experiments of this invention revealed that if the methacrylic acid content in the ethylene-co-methacrylic acid copolymer is too low, it will be insoluble and therefore cannot be applied to the fire-retardant coating of this invention.

[0018] As a preferred embodiment, the weight ratio of the ethylene-co-acrylic acid copolymer dispersion and / or the ethylene-co-methacrylic acid copolymer dispersion to the ethylene vinyl acetate copolymer emulsion is 1:2-2:1. Specifically, the weight ratio of the ethylene-co-acrylic acid copolymer dispersion to the ethylene vinyl acetate copolymer emulsion is 1:2-2:1, or the weight ratio of the ethylene-co-methacrylic acid copolymer dispersion to the ethylene vinyl acetate copolymer emulsion is 1:2-2:1, or the total weight of the ethylene-co-acrylic acid copolymer dispersion and the ethylene-co-methacrylic acid copolymer dispersion to the weight ratio of the ethylene vinyl acetate copolymer emulsion is 1:2-2:1.

[0019] As a preferred embodiment, the waterborne resin is an ethylene-co-methacrylic acid copolymer dispersion and an ethylene vinyl acetate emulsion copolymer in a weight ratio of 1:2 to 2:1.

[0020] As a preferred embodiment, the glass microspheres are present in an amount of 10-20 parts by weight. If the content of the glass microspheres is too high, the coating cannot be prepared due to the excessive water absorption of the microspheres.

[0021] As a preferred embodiment, the water-based pigment includes at least one of water-based black pigment, water-based iron red pigment, water-based yellow pigment, water-based blue pigment, water-based purple pigment, and water-based white pigment.

[0022] As a preferred embodiment, the filler slurry comprises the following components in parts by weight:

[0023]

[0024] As a preferred embodiment, the pigments and fillers are selected from at least one of barium sulfate, talc, and titanium dioxide.

[0025] As a preferred embodiment, the defoamer is selected from at least one of mineral oil-based defoamers and modified polyether-modified siloxanes.

[0026] As a preferred option, the matting agent is selected from E1011, Tego OK520, etc. At least one of C906.

[0027] As a preferred embodiment, the dispersant is selected from nonionic wetting and dispersing agents.

[0028] As a preferred embodiment, the pigments and fillers comprise the following raw material components in parts by weight: 0-35 parts barium sulfate, 0-40 parts talc, 0-70 parts titanium dioxide; and the contents of barium sulfate, talc, and titanium dioxide are all 0 parts.

[0029] As a preferred embodiment, the defoamer is selected from at least one of BYK011, BYK032, BYK028, and Tego Airex 902W.

[0030] As a preferred embodiment, the dispersant is selected from at least one of Tego Dispers 760W and BYK190.

[0031] As a preferred embodiment, the method for preparing the filler slurry includes the following steps: adding pigments, fillers, matting powder, defoamer, dispersant and water weighed in parts by weight into a grinding mill, and grinding and dispersing to prepare the filler slurry.

[0032] As a preferred embodiment, the flame retardant is selected from at least one of alkyl phosphate esters and nitrogen-phosphorus composite flame retardants.

[0033] As a further preferred embodiment, the flame retardant is selected from nitrogen-phosphorus composite flame retardants. More preferably, the flame retardant is at least one of melamine-type nitrogen-phosphorus composite flame retardants and ammonium polyphosphate-type nitrogen-phosphorus composite flame retardants.

[0034] As a preferred embodiment, the pH adjuster is selected from at least one of dimethylethanolamine, 2-amino-2-methyl-1-propanol, ammonia, and triethylamine.

[0035] As a preferred embodiment, the additives include at least one of defoamers, dispersants, and rheology modifiers.

[0036] As a preferred embodiment, the defoamer is selected from at least one of mineral oil-based defoamers and modified polyether-modified siloxanes;

[0037] As a preferred embodiment, the dispersant is selected from polyether-modified siloxanes.

[0038] As a preferred embodiment, the rheology modifier is selected from at least one of BYK Laponite-RDS, RHEOLATE 299, ASE60, and HV30.

[0039] As a preferred embodiment, the defoamer is selected from at least one of BYK011, BYK032, BYK028, and Tego902W;

[0040] As a preferred embodiment, the dispersant is selected from at least one of Tego-270, BYK190, and BYK192.

[0041] Secondly, the present invention provides a method for preparing a fire-retardant coating for aerogel felt encapsulation, comprising the following steps:

[0042] A. Weigh out the water-based resin, additives and water, mix them, and disperse them at high speed to prepare a high-shear water-based base material;

[0043] B. Add the weighed water-based color paste, filler paste, glass microspheres and organic flame retardant to the high-shear water-based base material prepared in step A, disperse at high speed, and then add a pH adjuster to control the pH at 8.0-8.5 to obtain the fireproof coating for aerogel felt encapsulation.

[0044] Compared with the prior art, the present invention has the following beneficial effects:

[0045] 1) This invention utilizes a specific water-based resin combined with a specific flame retardant to prepare an encapsulating coating for aerogel felt with fire-retardant properties. Testing has shown that its fire resistance rating can reach levels 1-5.

[0046] 2) This invention further utilizes a compound of EAA and / or EMAA with EVA, and adds a certain amount of glass microspheres to prepare an encapsulation coating for aerogel felt that balances fire resistance and flexibility. Testing shows that its fire resistance rating can reach level 4-5, and its flexibility allows for bending at 180° without cracking. Detailed Implementation

[0047] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention. These all fall within the scope of protection of the present invention.

[0048] The terms "preferred," "more preferably," and "more suitable" used in this invention refer to embodiments of the invention that provide certain beneficial effects under certain circumstances. However, other embodiments may also be preferred under the same or other circumstances. Furthermore, the description of one or more preferred embodiments does not imply that other embodiments are unavailable, nor is it intended to exclude other embodiments from the scope of this invention.

[0049] It should be understood that, except in any operational instance or otherwise indicated, all figures representing the amounts of ingredients used, for example, in the specification and claims, should be understood to be modified in all cases by the term "about". Therefore, unless otherwise stated, the numerical parameters set forth in the following specification and appended claims are approximations varying with the desired performance to be obtained according to the invention. It is not at all an attempt to limit the application of the doctrine of equivalents to the scope of the claims; each numerical parameter should be interpreted at least according to the number of significant figures reported and by applying ordinary rounding techniques.

[0050] Although the numerical ranges and parameters illustrating the broad scope of the invention are approximate, the values ​​listed in the specific examples are reported as precisely as possible. However, any numerical value inherently contains some error that is necessarily caused by the standard deviation found in their respective test measurements.

[0051] In the following embodiments, a fire-retardant coating for aerogel felt encapsulation is provided, comprising the following components in parts by weight:

[0052]

[0053] In one specific embodiment, the aqueous resin includes at least one of ethylene vinyl acetate copolymer emulsion, ethylene-co-acrylic acid copolymer dispersion, and ethylene-co-methacrylic acid copolymer dispersion.

[0054] In one specific embodiment, the water-based colorant includes at least one of water-based black colorant, water-based iron red colorant, water-based yellow colorant, water-based blue colorant, water-based purple colorant, and water-based white colorant. The type of water-based colorant can be selected according to the color requirements of the coating, and the present invention does not impose any particular limitation. When there is no color requirement, the water-based colorant may not be added, that is, the content of water-based colorant is 0 parts.

[0055] In one specific embodiment, the filler slurry comprises the following components in parts by weight:

[0056]

[0057] The filler slurry is prepared by adding pigments, fillers, matting powder, defoamer, dispersant and water weighed in parts by weight into a grinding mill and grinding and dispersing to prepare the filler slurry.

[0058] In one specific embodiment, the pigments and fillers are selected from at least one of barium sulfate, talc, and titanium dioxide; more preferably, the pigments and fillers include the following raw material components in parts by weight: 0-35 parts barium sulfate, 0-40 parts talc, 0-70 parts titanium dioxide; and the contents of barium sulfate, talc, and titanium dioxide are all 0 parts.

[0059] In one specific embodiment, the filler slurry comprises the following components in parts by weight: 20-40 parts water, 5-35 parts barium sulfate, 5-40 parts talc, 0-60 parts titanium dioxide, 1-5 parts matting agent, 2-5 parts defoamer, and 5-17 parts dispersant.

[0060] The defoamer is selected from at least one of mineral oil defoamers and modified polyether-modified siloxanes, such as BYK011, BYK032, BYK028, Tego Airex 902W, etc., and the present invention does not impose any particular limitation.

[0061] The matting agent is selected from E1011, Tego OK520, etc. At least one of C906, without any particular limitation in this invention.

[0062] The dispersant is selected from nonionic wetting and dispersing agents, such as Tego Dispers 760W, BYK190, etc., and the present invention does not impose any particular limitation.

[0063] In one specific embodiment, the flame retardant used in the coating is selected from nitrogen-phosphorus composite flame retardants. Specifically, at least one of melamine-type nitrogen-phosphorus composite flame retardants and ammonium polyphosphate-type nitrogen-phosphorus composite flame retardants can be used. In one specific embodiment, when the ammonium polyphosphate-type nitrogen-phosphorus flame retardant used is HF-202 (Shifang Taifeng Flame Retardant Co., Ltd.), HE-213T (Shifang Taifeng Flame Retardant Co., Ltd.), Exolit AP 435 (Clariant Chemicals (China) Co., Ltd.), or Exolit AP 462 (Clariant Chemicals (China) Co., Ltd.), the same or similar effects can be achieved.

[0064] In one specific embodiment, the pH adjuster used in the coating is selected from at least one of dimethylethanolamine, 2-amino-2-methyl-1-propanol, ammonia, and triethylamine, to adjust the pH value of the coating to 8.0 to 8.5.

[0065] In one specific embodiment, the additives used in the coating include defoamers, dispersants, and rheology modifiers. The defoamer is selected from at least one of mineral oil-based defoamers and modified polyether-modified siloxanes, such as BYK011, BYK032, BYK028, Tego902W, etc., and this invention does not impose any particular limitation. The dispersant is selected from polyether-modified siloxanes, such as Tego-270, BYK190, BYK192, etc., and this invention does not impose any particular limitation. The rheology modifier is selected from at least one of BYK Laponite-RDS, RHEOLATE 299, ASE60, HV30, and this invention does not impose any particular limitation.

[0066] In one specific embodiment, the purpose of adding water is to adjust the viscosity of the finished coating. Any value of 0-20 parts by weight can meet the viscosity requirements of the coating, and the present invention does not impose any particular limitation.

[0067] Under the above conditions, the heat-insulating and fire-retardant coating for aerogel encapsulation of the present invention can be prepared.

[0068] In the following embodiments, the raw materials used in the preparation of the specific coatings and their sources are as follows:

[0069] EVA-1 is DA-102H EVA emulsion, purchased from Dalian Chemical Co., Ltd. It is a high elongation at break, flame-retardant ethylene vinyl acetate copolymer emulsion with a Tg of 0℃ and a molar ratio of ethylene to vinyl acetate of 2:8.

[0070] EVA-2 is a DA-104EVA emulsion purchased from Dalian Chemical Co., Ltd. It is an ethylene-vinyl acetate copolymer emulsion with a Tg < -10℃ and a molar ratio of ethylene to vinyl acetate of 3:7.

[0071] EVA-3 is DA0511 EVA emulsion, purchased from Dalian Chemical Co., Ltd. It is an ethylene-vinyl acetate copolymer emulsion with a Tg of 12-18℃ and a molar ratio of ethylene to vinyl acetate of 1:9.

[0072] EVA-4 is a DA-207EVA emulsion purchased from Dalian Chemical Co., Ltd. It is an ethylene-vinyl acetate copolymer emulsion with a Tg < 0℃ and a molar ratio of ethylene to vinyl acetate of 2:8.

[0073] EVA-5 is a 707BJ EVA emulsion purchased from Beijing Dongfang Chemical Plant. It is an ethylene-vinyl acetate copolymer emulsion with a Tg of 5℃ and a molar ratio of ethylene to vinyl acetate of 2:8.

[0074] The EAA dispersion was prepared by mixing EAA with water and NaOH in a ratio of 1:98:1 and stirring evenly at 100°C. The EAA used in the following examples was a water-dispersible EAA purchased from SK Corporation of South Korea, which was 5980I ethylene-co-acrylic acid copolymer with an acrylic acid content of 20.5 wt%.

[0075] The EMAA dispersion was prepared by mixing EMAA with water and NaOH in a ratio of 1:95:4 and stirring at 100°C until homogeneous. The EMAA used in the following examples was a waterborne saline resin purchased from Dow Chemical, which is HDP3001 ethylene-co-methacrylic acid copolymer with a methacrylic acid content of 26 wt%.

[0076] The water-based high-pigment black paste (Vivid Black EI0600-1) was purchased from Zhejiang Nami New Materials Co., Ltd.

[0077] The alkyl phosphate ester was purchased from Jiangsu Weiguan New Material Technology Co., Ltd.

[0078] HF-202 was purchased from Shifang Taifeng Flame Retardant Co., Ltd., and is a polyphosphate ammonium type nitrogen-phosphorus composite flame retardant.

[0079] The glass microspheres were purchased from 3M, model VS 5500 3M, with a particle size D50 of 20-60 μm.

[0080] RHEOLATE 299, a polyurethane-associated waterborne rheology modifier, was purchased from Haimingsideqian.

[0081] Dimethylethanolamine (DMEA (10%)) was purchased from BASF.

[0082] The defoamer is a modified polyether-modified siloxane, model BYK-011, purchased from BYK Company.

[0083] The dispersant was a polyether-modified siloxane, model Tego-270, purchased from Tego.

[0084] The barium sulfate had a particle size of 3000 mesh and was purchased from Yangzhou Yuxin Powder Company.

[0085] The talc powder has a particle size of 3000 mesh and was purchased from Yangzhou Yuxin Powder Company.

[0086] The titanium dioxide is grade 902+ and was purchased from Chemours Titanium Dioxide Technology Co., Ltd.

[0087] The matting agent is model E1011 and was purchased from Tosoh Corporation of Japan.

[0088] The nonionic wetting and dispersing agent was Tego Dispers 760W, purchased from Tego.

[0089] Example 1

[0090] This embodiment provides a fire-retardant coating for aerogel felt encapsulation, comprising ethylene-vinyl acetate emulsion (EVA-1), water-based high-pigment black paste (Vivid Black EI0600-1), filler slurry, flame retardant (alkyl phosphate), pH adjuster (10% DMEA, i.e., a 10% aqueous solution of DMEA), defoamer (BYK-011), dispersant (Tego-270), rheology modifier (RHEOLATE 299), and water. The filler slurry is composed of the raw material components shown in Table 1. The weight proportions of each component used in the fire-retardant coating are shown in Table 2.

[0091] The preparation steps of the fire-retardant coating for aerogel felt encapsulation are as follows:

[0092] 1) Mix the high-performance resin dispersion, rheology modifier, defoamer and dispersant weighed according to the parts in Table 2, and disperse them at high speed to prepare a uniform high-shear waterborne base material.

[0093] 2) Weigh out the following components according to the weight percentages in Table 1: barium sulfate, talc, titanium dioxide, E1011, BYK-011, TegoDispers 760W, and water. Add these components to a grinder and grind to disperse and prepare a filler slurry. Proceed according to GB / T

[0094] The "Determination of Grinding Fineness of Paints, Varnishes and Printing Inks" (1724-2019) defines the fineness as below 20 μm.

[0095] 3) Add water-based high-pigment black paste, filler slurry prepared in step 2), and flame retardant to the water-based base material obtained in step 1) and disperse at high speed, according to GB / T 1724-2019 Determination of grinding fineness of paints, varnishes and printing inks.

[0096] Once the particle size is determined to be below 20 μm, a pH adjuster is added to adjust the pH to 8.0–8.5, thus obtaining the fire-retardant coating for aerogel encapsulation.

[0097] Example 2

[0098] This embodiment provides a fire-retardant coating for aerogel felt encapsulation, comprising ethylene-vinyl acetate emulsion (EVA-1), water-based high-pigment black paste (Vivid Black EI0600-1), filler slurry, flame retardant (66% nitrogen-phosphorus composite flame retardant, i.e., HF-202 diluted with water to a mass content of 66%), pH adjuster (10% DMEA, i.e., a 10% DMEA aqueous solution), defoamer (BYK-011), dispersant (Tego-270), rheology modifier (RHEOLATE 299), and water. The filler slurry is composed of the raw material components shown in Table 1. The weight proportions of each component used in the fire-retardant coating are shown in Table 2. The preparation method of the fire-retardant coating for aerogel felt encapsulation is the same as in Example 1.

[0099] Example 3

[0100] This embodiment provides a fire-retardant coating for aerogel felt encapsulation, comprising ethylene-vinyl acetate emulsion (EVA-2), water-based high-pigment black paste (Vivid Black EI0600-1), filler slurry, flame retardant (66% nitrogen-phosphorus composite flame retardant, i.e., HF-202 diluted with water to a mass content of 66%), pH adjuster (10% DMEA, i.e., a 10% DMEA aqueous solution), defoamer (BYK-011), dispersant (Tego-270), rheology modifier (RHEOLATE 299), and water. The filler slurry is composed of the raw material components shown in Table 1. The weight proportions of each component used in the fire-retardant coating are shown in Table 2. The preparation method of the fire-retardant coating for aerogel felt encapsulation is the same as in Example 1.

[0101] Example 4

[0102] This embodiment provides a fire-retardant coating for aerogel felt encapsulation, comprising ethylene-vinyl acetate emulsion (EVA-3), water-based high-pigment black paste (Vivid Black EI0600-1), filler slurry, flame retardant (66% nitrogen-phosphorus composite flame retardant, i.e., HF-202 diluted with water to a mass content of 66%), pH adjuster (10% DMEA, i.e., a 10% DMEA aqueous solution), defoamer (BYK-011), dispersant (Tego-270), rheology modifier (RHEOLATE 299), and water. The filler slurry is composed of the raw material components shown in Table 1. The weight proportions of each component used in the fire-retardant coating are shown in Table 2. The preparation method of the fire-retardant coating for aerogel felt encapsulation is the same as in Example 1.

[0103] Example 5

[0104] This embodiment provides a fire-retardant coating for aerogel felt encapsulation, comprising ethylene-vinyl acetate emulsion (EVA-4), water-based high-pigment black paste (Vivid Black EI0600-1), filler slurry, flame retardant (66% nitrogen-phosphorus composite flame retardant, i.e., HF-202 diluted with water to a mass content of 66%), pH adjuster (10% DMEA, i.e., a 10% DMEA aqueous solution), defoamer (BYK-011), dispersant (Tego-270), rheology modifier (RHEOLATE 299), and water. The filler slurry is composed of the raw material components shown in Table 1. The weight proportions of each component used in the fire-retardant coating are shown in Table 2. The preparation method of the fire-retardant coating for aerogel felt encapsulation is the same as in Example 1.

[0105] Example 6

[0106] This embodiment provides a fire-retardant coating for aerogel felt encapsulation, comprising ethylene-vinyl acetate emulsion (EVA-5), water-based high-pigment black paste (Vivid Black EI0600-1), filler slurry, flame retardant (66% nitrogen-phosphorus composite flame retardant, i.e., HF-202 diluted with water to a mass content of 66%), pH adjuster (10% DMEA, i.e., a 10% DMEA aqueous solution), defoamer (BYK-011), dispersant (Tego-270), rheology modifier (RHEOLATE 299), and water. The filler slurry is composed of the raw material components shown in Table 1. The weight proportions of each component used in the fire-retardant coating are shown in Table 2. The preparation method of the fire-retardant coating for aerogel felt encapsulation is the same as in Example 1.

[0107] Example 7

[0108] This embodiment provides a fire-retardant coating for aerogel felt encapsulation, comprising ethylene-vinyl acetate emulsion (EVA-1), water-based high-pigment black paste (Vivid Black EI0600-1), filler slurry, flame retardant (66% nitrogen-phosphorus composite flame retardant, i.e., HF-202 diluted with water to a mass content of 66%), pH adjuster (10% DMEA, i.e., a 10% DMEA aqueous solution), defoamer (BYK-011), dispersant (Tego-270), rheology modifier (RHEOLATE 299), and water. The filler slurry is composed of the raw material components shown in Table 1. The weight proportions of each component used in the fire-retardant coating are shown in Table 2. The preparation method of the fire-retardant coating for aerogel felt encapsulation is the same as in Example 1.

[0109] Example 8

[0110] This embodiment provides a fire-retardant coating for aerogel felt encapsulation, comprising ethylene-vinyl acetate emulsion (EVA-1), water-based high-pigment black paste (Vivid Black EI0600-1), filler slurry, flame retardant (alkyl phosphate), glass microspheres (VS5500 3M), pH adjuster (10% DMEA, i.e., a 10% aqueous solution of DMEA), defoamer (BYK-011), dispersant (Tego-270), rheology modifier (RHEOLATE 299), and water. The filler slurry is composed of the raw material components shown in Table 1. The weight proportions of each component used in the fire-retardant coating are shown in Table 2. The preparation method of the fire-retardant coating for aerogel felt encapsulation is basically the same as in Example 1, except that glass microspheres are added in step 3).

[0111] Example 9

[0112] This embodiment provides a fire-retardant coating for aerogel felt encapsulation, comprising ethylene-vinyl acetate emulsion and aqueous dispersion resin (EVA-1 and EAA dispersion), water-based high-pigment black paste (Vivid Black EI0600-1), filler slurry, flame retardant (66% nitrogen-phosphorus composite flame retardant, i.e., HF-202 diluted with water to a mass content of 66%), pH adjuster (10% DMEA, i.e., a 10% DMEA aqueous solution), defoamer (BYK-011), dispersant (Tego-270), rheology modifier (RHEOLATE 299), and water. The filler slurry is composed of the raw material components shown in Table 1. The weight proportions of each component used in the fire-retardant coating are shown in Table 2. The preparation method of the fire-retardant coating for aerogel felt encapsulation is basically the same as in Example 1.

[0113] Example 10

[0114] This embodiment provides a fire-retardant coating for aerogel felt encapsulation, comprising an aqueous dispersion resin (EAA dispersion), an aqueous high-pigment black paste (Vivid Black EI0600-1), a filler slurry, a flame retardant (66% nitrogen-phosphorus composite flame retardant, i.e., HF-202 diluted with water to a mass content of 66%), glass microspheres (VS 5500 3M), a pH adjuster (10% DMEA, i.e., a 10% DMEA aqueous solution), a defoamer (BYK-011), a dispersant (Tego-270), a rheology modifier (RHEOLATE299), and water. The filler slurry is composed of the raw material components shown in Table 1. The weight proportions of each component used in the fire-retardant coating are shown in Table 2. The preparation method of the fire-retardant coating for aerogel felt encapsulation is the same as in Example 8.

[0115] Example 11

[0116] This embodiment provides a fire-retardant coating for aerogel felt encapsulation, comprising an aqueous dispersion resin (EVA-1 and EMAA dispersion), an aqueous high-pigment black paste (Vivid Black EI0600-1), a filler slurry, a flame retardant (66% nitrogen-phosphorus composite flame retardant, i.e., HKFR-P07 diluted with water to a mass content of 66%), a pH adjuster (10% DMEA, i.e., a 10% DMEA aqueous solution), a defoamer (BYK-011), a dispersant (Tego-270), a rheology modifier (RHEOLATE 299), and water. The filler slurry is composed of the raw material components shown in Table 1. The weight proportions of each component used in the fire-retardant coating are shown in Table 2. The preparation method of the fire-retardant coating for aerogel felt encapsulation is the same as in Example 1.

[0117] Example 12

[0118] This embodiment provides a fire-retardant coating for aerogel felt encapsulation, comprising an aqueous dispersion resin (EMAA dispersion), an aqueous high-pigment black paste (Vivid Black EI0600-1), a filler slurry, a flame retardant (66% nitrogen-phosphorus composite flame retardant, i.e., HF-202 diluted with water to a mass content of 66%), glass microspheres (VS 5500 3M), a pH adjuster (10% DMEA, i.e., a 10% DMEA aqueous solution), a defoamer (BYK-011), a dispersant (Tego-270), a rheology modifier (RHEOLATE299), and water. The filler slurry is composed of the raw material components shown in Table 1. The weight proportions of each component used in the fire-retardant coating are shown in Table 2. The preparation method of the fire-retardant coating for aerogel felt encapsulation is the same as in Example 8.

[0119] Table 1 Raw material ratio of filler slurry

[0120]

[0121]

[0122] Table 2 Raw materials and weight parts of fire-retardant coatings

[0123]

[0124] Note: 66% nitrogen-phosphorus composite flame retardant is an aqueous dispersion of nitrogen-phosphorus composite flame retardant; 10% DMEA is a 10% mass content DMEA aqueous solution. The addition amount in Table 1 is the weight part of 10% DMEA, which is equivalent to 0.1 parts by weight of DMEA. The amount of DMEA added can be adjusted according to the pH of the coating, which is controlled within the range of 8.0 to 8.5.

[0125] Example 13

[0126] This embodiment provides a fireproof coating for aerogel felt encapsulation. The components and weight percentages used are basically the same as those in Embodiment 10. The only difference is that the filler slurry used in this embodiment is composed of the raw material components shown in Table 3. The flame retardant used in this embodiment is a 66% nitrogen-phosphorus composite flame retardant, namely HF-202, which is prepared by adding water to form a solution with a mass content of 66%.

[0127] The preparation steps for the fire-retardant coating for aerogel felt encapsulation are the same as in Example 10.

[0128] Example 14

[0129] This embodiment provides a fireproof coating for aerogel felt encapsulation. The components and weight percentages used are basically the same as those in Embodiment 10. The only difference is that the filler slurry used in this embodiment is composed of the raw material components shown in Table 3. The flame retardant used in this embodiment is a 66% nitrogen-phosphorus composite flame retardant, namely HF-202, which is prepared by adding water to form a solution with a mass content of 66%.

[0130] The preparation steps for the fire-retardant coating for aerogel felt encapsulation are the same as in Example 10.

[0131] Example 15

[0132] This embodiment provides a fireproof coating for aerogel felt encapsulation. The components and weight percentages used are basically the same as those in Embodiment 10. The only difference is that the filler slurry used in this embodiment is composed of the raw material components shown in Table 3. The flame retardant used in this embodiment is a 66% nitrogen-phosphorus composite flame retardant, namely HF-202, which is prepared by adding water to form a solution with a mass content of 66%.

[0133] The preparation steps for the fire-retardant coating for aerogel felt encapsulation are the same as in Example 10.

[0134] Table 3 Raw material ratio of filler slurry

[0135]

[0136] Examples 16-27

[0137] Examples 16-27 provide a fire-retardant coating for aerogel felt encapsulation, comprising ethylene-vinyl acetate emulsion and / or aqueous dispersion resin (EAA dispersion and / or EMAA dispersion), water-based high-pigment black paste (Vivid Black EI0600-1), filler slurry, flame retardant (66% nitrogen-phosphorus composite flame retardant, i.e., HF-202 diluted with water to a 66% mass content solution), glass microspheres (VS 5500 3M), pH adjuster (10% DMEA, i.e., a 10% DMEA aqueous solution), defoamer (BYK-011), dispersant (Tego-270), rheology modifier (RHEOLATE 299), and water. The filler slurry is composed of the raw material components shown in Table 1 above. The weight proportions of each component used in the fire-retardant coating are shown in Table 4. The preparation method of the fire-retardant coating for aerogel felt encapsulation is the same as in Example 8.

[0138] Table 4 Raw materials and weight parts of fire-retardant coatings

[0139]

[0140] Performance verification:

[0141] 1) After the fire-retardant coatings prepared in the above embodiments and comparative examples were formed into films, the film properties of each coating were tested. The flame retardant performance was tested according to the standard "UL 94EN STANDARD FOR SAFETY Tests for Flammability of Plastic Materials for Parts in Devices and Appliances", and the flexibility was tested according to the standard "GB / T 1731-2020 Test Method for Flexibility of Paint Films and Putty Films".

[0142] 2) The coatings prepared in the above embodiments were applied to the surface of the aerogel felt by dip coating, and the aerogel felt was encapsulated. The encapsulated aerogel felt was then subjected to fire resistance testing. The testing equipment used was the S8162X mica board combustion tester manufactured by Shanghai Sixuan Testing Equipment Co., Ltd. The specific method for the fire resistance test was as follows: the aerogel was selected as pre-oxidized fiber-supported silica aerogel with a thermal conductivity of 0.018–0.022 W / (m·K) and a thickness of 3.4 mm. After coating both sides of the aerogel felt with the coatings prepared in each embodiment, a coating layer was formed, and then it was cut into 15 cm × 15 cm test specimens. The two sides of the test specimen with the coating were used as the front and back sides, respectively. The front side was subjected to open flame erosion at 900–1000℃. The change in the appearance of the coating on the front side with erosion time was tested, and the temperature change on the back side with erosion time was monitored. Aerogel felt material (i.e., uncoated aerogel felt) was used as a test sample and tested using this method. The temperature on the back of the test sample reached 186.5℃ in 60 seconds and 272.7℃ in 300 seconds. Based on this, and in conjunction with the requirements for thermal diffusion in the draft of GB 38031 "Safety Requirements for Power Batteries for Electric Vehicles", a fire resistance rating standard for aerogel felt encapsulation was designed. The specific fire resistance classifications are shown in Table 5.

[0143] Table 5

[0144]

[0145] The test results for each sample are shown in Table 6.

[0146] Table 6

[0147]

[0148]

[0149] As shown in Table 6, when EVA is used alone as the film-forming resin, the fire rating of the prepared coating is 1-3, and the coating prepared by using EVA-3 alone cracks when bent at 180° (Examples 2-6); when EAA or EMAA is used alone as the film-forming resin, cracking occurs when bent at 180° (Examples 10, 12, 16, 18); when EAA and / or EMAA are compounded with EVA as the main resin, the fire rating of the prepared coating can reach 4-5, and no cracking occurs when bent at 180° (Examples 9, 11, 13-15, 17, 19-25).

[0150] As can be seen from the results in Table 6, when alkyl phosphate is used as the flame retardant, the fire rating is only 0, while when nitrogen-phosphorus composite flame retardant is used, the fire rating is significantly improved (comparison between Examples 1 and 2).

[0151] As can be seen from the results in Table 6, the addition of glass microspheres to the coating of the present invention can further improve the fire resistance rating and prevent it from cracking when bent at 180° (comparison of Examples 23 and 27).

[0152] This invention has many specific applications, and the above description is only a preferred embodiment. It should be noted that the above embodiments are for illustrative purposes only and are not intended to limit the scope of protection of this invention. For those skilled in the art, several improvements can be made without departing from the principle of this invention, and these improvements should also be considered within the scope of protection of this invention.

Claims

1. A fire-retardant coating for aerogel felt encapsulation, characterized in that, The components include the following parts by weight: 30-50 parts of water-based resin 0-10 parts of water-based color paste 20-50 parts of filler slurry 8-30 parts flame retardant 10-20 parts of glass microspheres pH adjuster 0.1-2 parts, 0.1-4 parts of auxiliary agent, 0-20 parts water; The aqueous resin is a combination of an ethylene-co-acrylic acid copolymer dispersion and / or an ethylene-co-methacrylic acid copolymer dispersion and an ethylene vinyl acetate copolymer emulsion; The flame retardant is a nitrogen-phosphorus composite flame retardant.

2. The fire-retardant coating for aerogel felt encapsulation according to claim 1, characterized in that, The glass transition temperature (Tg) of the ethylene vinyl acetate copolymer emulsion is 20°C. o Below C, the molar ratio of ethylene to vinyl acetate is below 3:7; In the ethylene-co-acrylic acid copolymer dispersion, the content of ethylene-co-acrylic acid copolymer is 1-10 wt%; in the ethylene-co-acrylic acid copolymer, the content of acrylic acid is greater than or equal to 20 wt%. The ethylene-co-methacrylic acid copolymer dispersion contains 1-2 wt% ethylene-co-methacrylic acid copolymer; the methacrylic acid content in the ethylene-co-methacrylic acid copolymer is greater than or equal to 25 wt%.

3. The fire-retardant coating for aerogel felt encapsulation according to claim 1, characterized in that, The weight ratio of the ethylene-co-acrylic acid copolymer dispersion and / or the ethylene-co-methacrylic acid copolymer dispersion to the ethylene vinyl acetate copolymer emulsion is 1:2-2:

1.

4. The fire-retardant coating for aerogel felt encapsulation according to claim 1, characterized in that, The water-based pigment includes at least one of water-based black pigment, water-based iron red pigment, water-based yellow pigment, water-based blue pigment, water-based purple pigment, and water-based white pigment.

5. The fire-retardant coating for aerogel felt encapsulation according to claim 1, characterized in that, The filler slurry comprises the following components in parts by weight: 20-40 parts water 30-70 parts of pigments and fillers 1-5 parts of matte powder 2-5 parts of defoamer Dispersant 5-17 parts.

6. The fire-retardant coating for aerogel felt encapsulation according to claim 5, characterized in that, The pigments and fillers are selected from at least one of barium sulfate, talc, and titanium dioxide. The defoamer is selected from at least one of mineral oil defoamers and modified polyether-modified siloxanes; The matting agent is selected from at least one of E1011, Tego OK520, and SYLOID® C906; The dispersant is selected from nonionic wetting and dispersing agents.

7. The fire-retardant coating for aerogel felt encapsulation according to claim 6, characterized in that, The pigments and fillers comprise the following raw material components in parts by weight: 0-35 parts barium sulfate, 0-40 parts talc, and 0-70 parts titanium dioxide; wherein the contents of barium sulfate, talc, and titanium dioxide are all different and are 0 parts. The defoamer is selected from at least one of BYK011, BYK032, BYK028, and Tego Airex 902W; The dispersant is selected from at least one of Tego Dispers 760W and BYK190.

8. The fire-retardant coating for aerogel felt encapsulation according to claim 5, 6, or 7, characterized in that, The method for preparing the filler slurry includes the following steps: adding pigments, fillers, matting powder, defoamer, dispersant and water weighed in parts by weight into a grinding mill, and grinding and dispersing to prepare the filler slurry.

9. The fire-retardant coating for aerogel felt encapsulation according to claim 1, characterized in that, The pH adjuster is selected from at least one of dimethylethanolamine, 2-amino-2-methyl-1-propanol, ammonia, and triethylamine.

10. The fire-retardant coating for aerogel felt encapsulation according to claim 1, characterized in that, The additives include at least one of defoamers, dispersants, and rheology modifiers.

11. The fire-retardant coating for aerogel felt encapsulation according to claim 10, characterized in that, The defoamer is selected from at least one of mineral oil defoamers and modified polyether-modified siloxanes; The dispersant is selected from polyether-modified siloxane; The rheology modifier is selected from at least one of BYK Laponite-RDS, RHEOLATE 299, ASE60, and HV30.

12. The fire-retardant coating for aerogel felt encapsulation according to claim 11, characterized in that, The defoamer is selected from at least one of BYK011, BYK032, BYK028, and Tego902W; The dispersant is selected from at least one of Tego-270, BYK190, and BYK192.

13. A method for preparing a fire-retardant coating for aerogel felt encapsulation according to any one of claims 1-12, characterized in that, Includes the following steps: A. Weigh out the water-based resin, additives and water, mix them, and disperse them at high speed to prepare a high-shear water-based base material; B. Add the weighed water-based color paste, filler paste, glass microspheres and flame retardant to the high-shear water-based base material prepared in step A, disperse at high speed, and then add a pH adjuster to control the pH at 8.0~8.5 to obtain the fireproof coating for aerogel felt encapsulation.

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