Preparation method and application of fireproof sponge

Abstract

The invention provides a preparation method of polyurethane sponge with integral fireproof and flame-retardant properties and good environmental protection property, and the preparation method comprises the following steps: mixing polyether polyol, isocyanate, environment-friendly fireproof microcapsules, a catalyst, a cross-linking agent, a foam stabilizer and a cooling type foaming agent, and carrying out foaming reaction to obtain polyurethane fireproof sponge, wherein the cooling type foaming agent is selected from at least one of perfluorohexanone, perfluorohexane, tetrafluorodibromoethane and heptafluoropropane; a capsule core material of the environment-friendly fireproof microcapsule is selected from at least one of carbon dioxide, heptafluoropropane, hexafluoropropane, perfluorohexanone, perfluorohexane, tetrafluorodibromoethane and trifluorotrichloroethane.

Description

Technical Field

[0001] The invention relates to the field of polyurethane sponges, and in particular to a preparation method of a fireproof sponge and application thereof. Background Art

[0002] Fireproof sponge, also known as flame retardant sponge, fireproof cotton or flame retardant cotton, is a porous material synthesized by adding flame retardant to polyurethane. Ordinary sponge is widely used in furniture manufacturing, packaging materials, baby carriage manufacturing, decoration, car accessories, etc. due to its characteristics of heat preservation, heat insulation, sound absorption, shock absorption, anti-static, good air permeability, etc.

[0003] Since ordinary sponges and sponge products are easy to burn, fires spread quickly, increasing casualties and property losses. Therefore, when used in places with fire risks, it is necessary to use fire-resistant sponges with good flame retardant properties, such as no open flames when burning, reducing burning time, delaying combustion, and blocking smoke to cause the fire to extinguish itself.

[0004] Most of the current fireproof sponges use halogen-containing flame retardants, such as CN117165063A, which release toxic and harmful gases during combustion and pollute the environment; most of them use a multi-layer adhesive method to stick a fireproof layer on the surface of an ordinary sponge, and the sponge only has fireproof ability on the surface, and the overall fireproof performance is insufficient, and there is a risk of the fireproof layer falling off after long-term use. In view of the shortcomings of the prior art, the present invention provides a method for preparing an environmentally friendly fireproof sponge using fireproof microcapsules, and the prepared sponge has excellent overall fireproof and flame retardant ability. Summary of the invention

[0005] In view of the above-mentioned deficiencies in the prior art, the present invention provides a method for preparing a polyurethane sponge which is fire-retardant and environmentally friendly.

[0006] The present invention is achieved through the following technical solutions:

[0007] In one aspect, the present invention provides a method for preparing a fireproof sponge, comprising: mixing polyether polyol, isocyanate, environmentally friendly fireproof microcapsules, a catalyst, a crosslinking agent, a foam stabilizer and a cooling foaming agent, and then performing a foaming reaction to obtain a polyurethane fireproof sponge;

[0008] Wherein, the cooling type foaming agent is selected from at least one of perfluorohexanone, perfluorohexane, tetrafluorodibromoethane and heptafluoropropane;

[0009] The capsule core material of the environmentally friendly fireproof microcapsule is selected from at least one of carbon dioxide, heptafluoropropane, hexafluoropropane, perfluorohexanone, perfluorohexane, tetrafluorodibromoethane and trifluorotrichloroethane.

[0010] The present invention applies fireproof microcapsules to polyurethane sponges, and uses materials with fire extinguishing properties as capsule core materials, which can effectively prevent and extinguish fires after the sponge catches fire. Compared with the prior art that uses phosphorus-containing flame retardants as capsule cores, on the one hand, the capsule core material of the present invention does not contain halogens and does not have environmental problems. On the other hand, the phosphorus-containing flame retardant functions to prevent the material from burning, while the capsule core material of the present invention functions to extinguish fires after catching fire, and the two are essentially different.

[0011] In a specific embodiment of the present invention, the temperature of the foaming reaction is 30-80°C, and the reaction time is 2-24h; preferably, the temperature of the foaming reaction is 50-60°C, and the reaction time is 8-16h. For example, the temperature of the foaming reaction is 30°C, 40°C, 50°C, 60°C, 70°C, 80°C, etc., and the reaction time is 2h, 4h, 6h, 8h, 10h, 12h, 14h, 16h, 18h, 20h, 22h, 24h, etc.

[0012] In a specific embodiment of the present invention, the amount of raw materials used, by weight, is: 100 parts of polyether polyol, 30-80 parts of isocyanate, 5-20 parts of environmentally friendly fireproof microcapsules, 0.01-1.5 parts of catalyst, 0.5-2 parts of cross-linking agent, 1-5 parts of foam stabilizer, and 2-3 parts of cooling foaming agent.

[0013] In the process of polyurethane synthesis, the conventional reaction temperature is about 120°C. After the inventor added environmentally friendly fireproof microcapsules to the raw materials of polyurethane, when the temperature rose to 80°C, it was found that the structure of the microcapsules was destroyed and the capsule core material was released. In order to solve this technical problem, the inventor improved the formula and proportion of the raw materials. On the one hand, the inventor replaced the conventional foaming agent water with a cooling foaming agent. The cooling foaming agent is a low-boiling point compound and has a fire extinguishing function. It evaporates and takes away heat during the reaction, plays a cooling role, and also has a foaming effect; on the other hand, the inventor adjusted the ratio between the reaction raw materials so that the foaming reaction can be carried out under low temperature conditions, and the obtained sponge has better mechanical properties.

[0014] Preferably, the amount of raw materials used, by weight, is: 100 parts of polyether polyol, 50-70 parts of isocyanate, 8-16 parts of environmentally friendly fireproof microcapsules, 0.7-1.1 parts of catalyst, 0.6-1 parts of cross-linking agent, 2.5-4.5 parts of foam stabilizer, and 2.5-2.8 parts of cooling foaming agent.

[0015] In the present invention, there is no particular limitation on the capsule wall material of the environmentally friendly fireproof microcapsules, and all capsule wall materials conventionally used in the art are applicable to the present invention.

[0016] Preferably, in a specific embodiment of the present invention, the capsule wall material of the environmentally friendly fireproof microcapsule is selected from at least one of epoxy resin, melamine resin, polyurea resin, polymethacrylate, phenolic resin, chitosan, β-cyclodextrin, polyglutamic acid, and gum arabic.

[0017] In the present invention, there is no particular limitation on the preparation method of the environmentally friendly fireproof microcapsules, and any method such as in-situ polymerization or interfacial polymerization may be used.

[0018] Preferably, in a specific embodiment of the present invention, the present invention adopts an in-situ polymerization method to prepare environmentally friendly fireproof microcapsules, and the specific steps include:

[0019] (1) dissolving an emulsifier in pure water and stirring, and pouring the capsule core material into the emulsifier aqueous solution for emulsification; the emulsifier is selected from at least one of sodium dodecylbenzene sulfonate, polyoxypropylene ether, SMA, and polyol fatty acid ester;

[0020] (2) After emulsification for 6-10 minutes, add the capsule wall material and stir thoroughly;

[0021] (3) After stirring for 6-10 minutes, add an acidic regulator to adjust the pH to 3-6;

[0022] (4) Keep the reaction at 10-40° C. for 5-8 hours to obtain the environmentally friendly fireproof microcapsules.

[0023] Preferably, the amount of the core material is 20-30wt%, the amount of the wall material is 30-40wt%, the amount of water is 35wt%, and the amount of the emulsifier is 5-10wt%.

[0024] In a specific embodiment of the present invention, the particle size D50 of the environmentally friendly fireproof microcapsules is 60-120 μm. If the particle size is too large, the mechanical strength of the prepared sponge will be reduced. If the particle size is too small, the pores of the sponge will be blocked and the air permeability will be reduced.

[0025] In a specific embodiment of the present invention, the isocyanate is selected from at least one of toluene diisocyanate (TDI), xylene methane diisocyanate (MDI), and polymethylene polyphenyl polyisocyanate (PAPI).

[0026] In a specific embodiment of the present invention, the catalyst is selected from at least one of an organic tin catalyst, an organic bismuth catalyst, and an amine catalyst.

[0027] Preferably, the organotin catalyst is at least one selected from stannous octoate, dibutyltin dilaurate, dibutyltin didodecylsulfide, and dibutyltin diacetate.

[0028] Preferably, the organic bismuth catalyst is selected from at least one of bismuth isooctanoate, bismuth dilaurate, bismuth neodecanoate, bismuth cyclohexaneate, bismuth oxide and bismuth nitrate.

[0029] Preferably, the amine catalyst is selected from at least one of triethylamine, 1,4-diazabicyclo[2.2.2]octane, pentamethyldiethylenetriamine, bis(dimethylaminoethyl)ether, pentamethyldipropylenetriamine, N,N-dimethylcyclohexylamine, and N-methyl-N-(N,N-dimethylaminoethyl)ethanolamine.

[0030] In the present invention, when the catalyst is an organic tin catalyst or an organic bismuth catalyst, the corresponding foaming reaction temperature is 50-80°C, and the reaction time is 2-20h; when the catalyst is an amine catalyst, the corresponding foaming reaction temperature is 30-50°C, and the reaction time is 5-24h.

[0031] In a specific embodiment of the present invention, the cross-linking agent is selected from at least one of ethylene glycol, glycerol, diethylene glycol, triethylene glycol, 1,4-butanediol, triethanolamine, diethanolamine, and ethylenediamine.

[0032] In a specific embodiment of the present invention, the foam stabilizer package is a hindered phenol antioxidant or a hindered amine light stabilizer.

[0033] Preferably, the foam stabilizer is selected from at least one of Chinox TP-35, Chisorb B2636H, K383, Tinuvin B75, PUR68, and RFCH800.

[0034] In a specific embodiment of the present invention, the method for preparing the fireproof sponge specifically comprises:

[0035] S1. Preparation of material A: Weigh polyether polyol, environmentally friendly fireproof microcapsules, catalyst, crosslinking agent, and foam stabilizer, stir them thoroughly in a container, and let them stand at room temperature for later use;

[0036] S2. Preparation of material B: weigh the cooling foaming agent and isocyanate, stir them thoroughly in a container, and let them stand at room temperature for later use;

[0037] S3, sponge body preparation: pump the reserved A material and B material into the foaming machine at the same time, mix and stir them thoroughly, and then continuously inject the mixture into the mold for foaming reaction;

[0038] S4, aging: After the product in step S3 is foamed and formed, it is aged at room temperature for 10-15 hours and then left to stand for use;

[0039] S5. Cutting and trimming: cutting and trimming the sponge body according to the required size to obtain the polyurethane fireproof sponge.

[0040] On the other hand, the present invention provides the use of the above-mentioned fireproof sponge in battery pack insulation materials.

[0041] Beneficial effects:

[0042] (1) Unlike traditional sponges that mostly use halogen-containing flame retardants, the sponge prepared by the present invention does not release toxic gases to pollute the environment during the fire retardant process, is smokeless and odorless, and is safe and reliable.

[0043] (2) Different from the traditional multi-layer sticky fireproof sponge, the sponge prepared by the present invention has excellent overall fireproof performance, and the fireproof ability will not be significantly reduced during long-term use.

[0044] (3) The fireproof sponge prepared by the present invention will not show obvious physical deformation phenomena such as deformation, expansion, tearing, etc. during the fireproofing and flame retardant process.

[0045] (4) The fireproof sponge prepared by the present invention can be reused 2 to 3 times, thereby reducing the use cost.

[0046] (5) The fireproof sponge prepared by the present invention is environmentally friendly, highly flame retardant, thermally stable, and has good air permeability.

[0047] (6) The fireproof sponge prepared by the present invention adopts a low-temperature foaming process, the microcapsule particle size is large and the addition amount is small, so the mechanical properties represented by tensile strength are good, it has good flexibility and has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 This is a process flow chart for preparing the fireproof sponge provided in Example 1 of the present invention. DETAILED DESCRIPTION

[0049] In order to make the technical problems, technical solutions and beneficial effects solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0050] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0051] The present invention is further described in detail below through specific embodiments.

[0052] Example 1

[0053] The present invention provides a method for preparing a polyurethane fireproof sponge, comprising the following steps:

[0054] Preparation of fireproof microcapsules:

[0055] (1) 50 g of emulsifier was dissolved in 2 kg of pure water and stirred, and 1.75 kg of perfluorohexanone was poured into the emulsifier aqueous solution for emulsification;

[0056] (2) After emulsification for 8 minutes, add melamine resin and stir thoroughly;

[0057] (3) After stirring for 8 min, add hydrochloric acid to adjust the pH to 5;

[0058] (4) The reaction was kept warm at 30°C for 7 hours to obtain fire-resistant microcapsules with a capsule particle size of D50 = 60 μm and D90 = 90 μm.

[0059] Preparation of fireproof sponge:

[0060] S1. Preparation of material A: Weigh 100 parts of polyether polyol, 12 parts of the above-mentioned fireproof microcapsules, 0.9 parts of stannous octoate, 3.2 parts of K383, and 0.8 parts of triethanolamine in parts by weight, stir them thoroughly and let them stand in a container. The stirring operation is to stir clockwise for 45 minutes, then stir counterclockwise for 25 minutes, and then use a stirring roller to stir for 15 minutes. Control the temperature at 20°C and set aside.

[0061] S2. Preparation of material B: weigh 2.6 parts of perfluorohexanone and 60 parts of toluene diisocyanate, stir them thoroughly in a container and let them stand at a temperature of 20°C for later use;

[0062] S3, preparation of sponge body: pump the reserved A material and B material into the mixing head of the horizontal foaming machine at the same time, mix and stir thoroughly for 20 seconds, control the stirring speed at more than 5000 rpm, and continuously inject the mixture into the mold for foaming reaction, the reaction temperature is 55°C, and the reaction time is 10 hours;

[0063] S4, aging: After the product in step S3 is foamed and formed, it is aged at room temperature for 12 hours and then left to stand for use;

[0064] S5. Cutting and trimming: After cutting the material head, the sponge body is trimmed according to a thickness of 2 cm to obtain a fireproof sponge.

[0065] Example 2

[0066] The present invention provides a method for preparing a polyurethane fireproof sponge, comprising the following steps:

[0067] Preparation of fireproof microcapsules:

[0068] (1) Dissolve 50 g of emulsifier in 2 kg of pure water and stir, and pour 1.8 kg of heptafluoropropane into the emulsifier aqueous solution for emulsification;

[0069] (2) After emulsification for 7 minutes, add melamine resin and stir thoroughly;

[0070] (3) After stirring for 7 min, add hydrochloric acid to adjust the pH to 5;

[0071] (4) The reaction was kept warm at 30°C for 7 hours to obtain fire-resistant microcapsules with a capsule particle size of D50 = 60 μm and D90 = 90 μm.

[0072] Preparation of fireproof sponge:

[0073] S1. Preparation of material A: 100 parts of polyether polyol, 8 parts of the above-mentioned fireproof microcapsules, 0.75 parts of bismuth isooctanoate, 2.5 parts of Chinox TP-35, and 1 part of ethylene glycol are weighed by weight, and the mixture is stirred and allowed to stand in a container. The stirring operation is to stir clockwise for 45 minutes, then stir counterclockwise for 25 minutes, and then use a stirring roller to stir the mixture for 15 minutes. The temperature is controlled at 20° C. and set aside.

[0074] S2. Preparation of material B: weigh 2.5 parts of heptafluoropropane and 55 parts of toluene diisocyanate, stir them thoroughly in a container and let them stand at a temperature of 20°C for later use;

[0075] S3, preparation of sponge body: pump the reserved A material and B material into the mixing head of the horizontal foaming machine at the same time, mix and stir thoroughly for 20 seconds, control the stirring speed at more than 5000 rpm, and continuously inject the mixture into the mold for foaming reaction, the reaction temperature is 75°C, and the reaction time is 7.5h;

[0076] S4, aging: After the product in step S3 is foamed and formed, it is aged at room temperature for 12 hours and then left to stand for use;

[0077] S5. Cutting and trimming: After cutting the material head, the sponge body is trimmed according to a thickness of 3 cm to obtain a fireproof sponge.

[0078] Example 3

[0079] The present invention provides a method for preparing a polyurethane fireproof sponge, comprising the following steps:

[0080] Preparation of fireproof microcapsules:

[0081] (1) 50 g of emulsifier was dissolved in 2 kg of pure water and stirred, and 1.5 kg of perfluorohexanone was poured into the emulsifier aqueous solution for emulsification;

[0082] (2) After emulsification for 8 minutes, add melamine resin and stir thoroughly;

[0083] (3) After stirring for 8 min, add hydrochloric acid to adjust the pH to 5;

[0084] (4) The reaction was kept at 30°C for 7 hours to obtain fire-resistant microcapsules with a particle size of D50 = 60 μm and D90 = 90 μm.

[0085] Preparation of fireproof sponge:

[0086] S1. Preparation of material A: weigh 100 parts of polyether polyol, 16 parts of fireproof microcapsules, 1.05 parts of pentamethyldiethylenetriamine, 4.1 parts of K383, and 0.6 parts of triethanolamine in parts by weight, stir them thoroughly in a container and let them stand. The stirring operation is to stir clockwise for 45 minutes, then stir counterclockwise for 25 minutes, and then use a stirring roller to stir for 15 minutes. The temperature is controlled at 20° C. and set aside.

[0087] S2. Preparation of material B: weigh 2.75 parts of perfluorohexanone and 69 parts of toluene diisocyanate, stir them thoroughly in a container and let them stand at a temperature of 20°C for later use;

[0088] S3, preparation of sponge body: pump the reserved A material and B material into the mixing head of the horizontal foaming machine, mix and stir thoroughly for 20 seconds, control the stirring speed at more than 5000 rpm, and continuously inject the mixture into the mold for foaming reaction, the reaction temperature is 53°C, and the reaction time is 11 hours;

[0089] S4, aging: After the product in step S3 is foamed and formed, it is aged at room temperature for 12 hours and then left to stand for use;

[0090] S5. Cutting and trimming: After cutting the material head, the sponge body is trimmed according to a thickness of 1 cm to obtain a fireproof sponge.

[0091] Comparative Example 1

[0092] Referring to Example 1, the fireproof microcapsules used in this comparative example are the same as those in Example 1. In the preparation step of the fireproof sponge, the perfluorohexanone in material B is replaced with water, and the remaining steps are consistent with Example 1. It is found that when the reaction temperature is 55°C, the foaming reaction cannot proceed. The foaming reaction temperature is adjusted to 98°C and the reaction time is 5h to obtain the fireproof sponge.

[0093] Comparative Example 2

[0094] Referring to Example 1, the difference between this comparative example and the example is that the amount of catalyst stannous octoate used in material A is 0.2 parts, the corresponding reaction temperature is 42° C., the reaction time is 16 hours, and the remaining steps are consistent with Example 1 to obtain a fireproof sponge.

[0095] Comparative Example 3

[0096] Preparation of fireproof sponge:

[0097] S1. Preparation of material A: Weigh 100 parts of polyether polyol, 0.75 parts of stannous octoate, 2.5 parts of K383, and 1 part of triethanolamine by weight, stir them thoroughly and let them stand in a container. The stirring operation is to stir clockwise for 45 minutes, then stir counterclockwise for 25 minutes, and then use a stirring roller to stir for 15 minutes. Control the temperature at 20°C and set aside.

[0098] S2. Preparation of material B: weigh 2.5 parts of water and 55 parts of toluene diisocyanate, stir them thoroughly in a container and let them stand at a temperature of 20°C for later use;

[0099] S3, preparation of sponge body: pump the reserved A material and B material into the mixing head of the horizontal foaming machine at the same time, mix and stir thoroughly for 20 seconds, control the stirring speed to be above 5000 rpm, and continuously inject the mixture into the mold for foaming reaction, the reaction temperature is 125°C, and the reaction time is 2.5h; S4, aging: after the product in step S3 is foamed and formed, mature it at room temperature for 12h and then stand it for use;

[0100] S5. Cutting and trimming: After cutting the material head, the sponge body is trimmed according to a thickness of 3 cm to obtain a fireproof sponge.

[0101] The fireproof sponges obtained in the above embodiments and comparative examples were subjected to fireproof performance test and tensile strength test; the fireproof performance test method was to place the sponge on a burning candle and record the time when the candle went out; the tensile strength test method was based on the national standard GB / T 528-2009, and the results are shown in Table 1.

[0102] Table 1

[0103] serial number Fire extinguishing time Tensile Strength Example 1 5s 80Kpa Example 2 13 s 72Kpa Example 3 8s 83Kpa Comparative Example 1 28s 78Kpa Comparative Example 2 9 s 28Kpa Comparative Example 3 Unable to extinguish fire 81Kpa

[0104] In Comparative Example 1, after the cooling foaming agent is replaced with water, the water cannot effectively reduce the reaction temperature, and the fire extinguishing performance of the obtained sponge is also poor. This is because in addition to reducing the reaction temperature, part of the cooling foaming agent remains in the sponge, which enhances the fire extinguishing effect.

[0105] In Comparative Example 2, the amounts of catalyst and isocyanate used are not within the scope of this patent. Although the obtained sponge has a good fire extinguishing effect, the reaction is slow and incomplete due to the low amount of catalyst added, which is manifested in its poor tensile strength.

[0106] Comparative Example 3 is a conventional sponge preparation process, without adding fireproof microcapsules, and cannot achieve the effect of fire extinguishing.

[0107] In summary, the fireproof sponge obtained by adopting the technical solution of the present invention can maintain the excellent tensile strength of the sponge while having an effective fire extinguishing effect, and will not pollute the environment, and has good application value.

[0108] The specific embodiments of the present invention are described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, a variety of simple modifications can be made to the technical solution of the present invention, and these simple modifications all belong to the protection scope of the present invention.

[0109] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

Claims

1. A method for preparing a fireproof sponge, characterized in that: The preparation method comprises: mixing polyether polyol, isocyanate, environmentally friendly fireproof microcapsules, catalyst, crosslinking agent, foam stabilizer and cooling foaming agent, and then performing foaming reaction to obtain polyurethane fireproof sponge; Wherein, the cooling type foaming agent is selected from at least one of perfluorohexanone, perfluorohexane, tetrafluorodibromoethane and heptafluoropropane; The capsule core material of the environmentally friendly fireproof microcapsule is selected from at least one of carbon dioxide, heptafluoropropane, hexafluoropropane, perfluorohexanone, perfluorohexane, tetrafluorodibromoethane and trifluorotrichloroethane.

2. The preparation method according to claim 1, characterized in that: The temperature of the foaming reaction is 30-80° C., and the reaction time is 2-24 hours.

3. The preparation method according to claim 1, characterized in that: In parts by weight, the amount of raw materials used is: 100 parts of polyether polyol, 30-80 parts of isocyanate, 5-20 parts of environmentally friendly fireproof microcapsules, 0.01-1.5 parts of catalyst, 0.5-2 parts of cross-linking agent, 1-5 parts of foam stabilizer, and 2-3 parts of cooling foaming agent; Preferably, the capsule wall material of the environmentally friendly fireproof microcapsule is selected from at least one of epoxy resin, melamine resin, polyurea resin, polymethacrylate, phenolic resin, chitosan, β-cyclodextrin, polyglutamic acid, and gum arabic.

4. The preparation method according to claim 1, characterized in that: The isocyanate is selected from at least one of toluene diisocyanate, xylene methane diisocyanate, and polymethylene polyphenyl polyisocyanate.

5. The preparation method according to claim 1, characterized in that: The catalyst is selected from at least one of an organic tin catalyst, an organic bismuth catalyst, and an amine catalyst; Preferably, the organotin catalyst is at least one selected from stannous octoate, dibutyltin dilaurate, dibutyltin didodecylsulfide, and dibutyltin diacetate; Preferably, the organic bismuth catalyst is selected from at least one of bismuth isooctanoate, bismuth dilaurate, bismuth neodecanoate, bismuth cyclohexaneate, bismuth oxide, and bismuth nitrate; Preferably, the amine catalyst is selected from at least one of triethylamine, 1,4-diazabicyclo[2.2.2]octane, pentamethyldiethylenetriamine, bis(dimethylaminoethyl)ether, pentamethyldipropylenetriamine, N,N-dimethylcyclohexylamine, and N-methyl-N-(N,N-dimethylaminoethyl)ethanolamine.

6. The preparation method according to claim 5, characterized in that: The catalyst is an organic tin catalyst or an organic bismuth catalyst, the temperature of the foaming reaction is 50-80° C., and the reaction time is 2-20 hours; or, The catalyst is an amine catalyst, the temperature of the foaming reaction is 30-50° C., and the reaction time is 5-24 hours.

7. The preparation method according to claim 1, characterized in that: The cross-linking agent is selected from at least one of ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, 1,4-butanediol, triethanolamine, diethanolamine, and ethylenediamine.

8. The preparation method according to claim 1, characterized in that: The foam stabilizer is selected from at least one of Chinox TP-35, Chisorb B2636H, K383, Tinuvin B75, PUR68, and RFCH800.

9. The preparation method according to claim 1, characterized in that: The preparation method specifically comprises: S1. Preparation of material A: Weigh polyether polyol, environmentally friendly fireproof microcapsules, catalyst, crosslinking agent, and foam stabilizer, stir them thoroughly in a container, and let them stand at room temperature for later use; S2. Preparation of material B: weigh the cooling type foaming agent and isocyanate, stir them thoroughly in a container, and let them stand at room temperature for later use; S3, sponge body preparation: pump the reserved A material and B material into the foaming machine at the same time, mix and stir them thoroughly, and then continuously inject the mixture into the mold for foaming reaction; S4, aging: After the product in step S3 is foamed and formed, it is aged at room temperature for 10-15 hours and then left to stand for use; S5. Cutting and trimming: cutting and trimming the sponge body according to the required size to obtain the polyurethane fireproof sponge.

10. Application of the fireproof sponge obtained according to the preparation method according to any one of claims 1 to 9 in thermal insulation materials for battery packs.

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