Flame-retardant polyurethane foam with low thermal conductivity and preparation method thereof

Abstract

The invention relates to low-thermal-conductivity flame-retardant polyurethane foam and a preparation method thereof, the low-thermal-conductivity flame-retardant polyurethane foam comprises the following raw materials by weight: 30-50 parts of polyol, which is a combination of polyether polyol and polyester polyol; 20 to 30 parts of isocyanate, wherein the isocyanate is a combination of toluene diisocynate and diphenylmethane diisocyanate; 3-8 parts of a foaming agent; 0.5-1.5 parts of a catalyst, wherein the catalyst is a combination of an amine catalyst and a tin catalyst; 10-20 parts of a flame retardant, wherein the flame retardant is a combination of a phosphorus-based flame retardant and a nitrogen-based flame retardant; 0-1 part of a surfactant; and 0-1 part of an anti-aging agent. According to the low-thermal-conductivity flame-retardant polyurethane foam and the preparation method thereof disclosed by the invention, systems such as polyol and isocyanate are reasonably designed, and a proper amount of auxiliaries are added, so that the foam has good physical and mechanical properties while having low thermal conductivity and flame retardance, and can meet the requirements of different application scenes.

Description

Technical Field

[0001] The invention belongs to the technical field of foam preparation, and particularly relates to low thermal conductivity flame-retardant polyurethane foam and a preparation method thereof. Background Art

[0002] As an important polymer material, polyurethane foam is widely used in many fields such as construction, automobiles, electronics, aerospace, etc. because of its excellent properties such as light weight, softness, sound absorption and shock absorption.

[0003] However, traditional polyurethane foam has the problems of high thermal conductivity and insufficient flame retardancy. In some application scenarios with high requirements for thermal insulation and fire safety, such as building exterior wall insulation, electronic equipment heat dissipation management, and thermal insulation protection in the aerospace field, the polyurethane foam in the existing technology is difficult to meet actual needs.

[0004] High thermal conductivity will lead to rapid heat transfer, reduce thermal insulation effects and increase energy consumption; while poor flame retardant properties will easily burn when encountering a fire source, releasing large amounts of toxic and harmful gases, posing a serious threat to the safety of life and property.

[0005] Therefore, it is of great practical significance to develop a polyurethane foam with both low thermal conductivity and good flame retardant properties. Summary of the invention

[0006] Purpose of the invention: In order to overcome the above shortcomings, the purpose of the present invention is to provide a low thermal conductivity flame retardant polyurethane foam and a preparation method thereof. The formula design is reasonable and the preparation method is simple, so that the foam has low thermal conductivity and flame retardant properties while also having good physical and mechanical properties, which can meet the needs of different application scenarios and has broad application prospects.

[0007] The objective of the present invention is achieved through the following technical solutions: A low thermal conductivity flame retardant polyurethane foam, comprising the following raw materials in parts by weight: 30-50 parts of polyol, wherein the polyol is a combination of polyether polyol and polyester polyol; 20-30 parts of isocyanate, wherein the isocyanate is a combination of toluene diisocyanate and diphenylmethane diisocyanate; 3~8 parts of foaming agent; 0.5-1.5 parts of a catalyst, wherein the catalyst is a combination of an amine catalyst and a tin catalyst; 10 to 20 parts of a flame retardant, wherein the flame retardant is a combination of a phosphorus-based flame retardant and a nitrogen-based flame retardant; Surfactant 0~1 part; Anti-aging agent 0~2 parts.

[0008] The low thermal conductivity flame retardant polyurethane foam described in the present invention rationally designs the polyol, isocyanate and catalyst system, and adds flame retardants, surfactants and anti-aging agents as additives, so that the foam has low thermal conductivity and flame retardant properties while also having good physical and mechanical properties, and can meet the needs of different application scenarios. Among them, polyether polyol and polyester polyol are used to form a polyol system. Polyether polyol has good flexibility and hydrolysis resistance, while polyester polyol can improve the strength and hardness of the foam. The reasonable combination of the two can make the foam have good physical properties. Toluene diisocyanate (TDI) and diphenylmethane diisocyanate (MDI) are used to form an isocyanate system. The mixed isocyanate system can provide suitable reaction activity and crosslinking density, which helps to form a stable foam structure. The catalyst uses a combination of amine catalysts and tin catalysts. The synergistic effect of the two can effectively promote the formation reaction of polyurethane and improve the reaction efficiency. The flame retardant uses a compound of phosphorus flame retardants and nitrogen flame retardants. The phosphorus flame retardants and nitrogen flame retardants cooperate with each other to significantly improve the flame retardant properties of the foam through the synergistic effect of gas phase flame retardancy and condensed phase flame retardancy. Surfactants and anti-aging agents are used to improve the surface properties and aging resistance of the foam.

[0009] Furthermore, in the above-mentioned low thermal conductivity flame-retardant polyurethane foam, the polyether polyol is a combination of one or more of polyether DL-4000D, polyether N330, polyether EP-3600, and polyether MN-500; the polyester polyol is a combination of one or more of PEA-3000, PBA-2000, PCL-2000, and PTA-3000.

[0010] Preferably, the polyether polyol is polyether DL-4000D, and the polyester polyol is PEA-3000.

[0011] Polyether DL-4000D has a high molecular weight, which can give the foam good flexibility and resilience. Its low unsaturation makes the foam less prone to oxidation and degradation during long-term use. It has excellent hydrolysis resistance and can effectively extend the service life of the foam. PEA-3000 is made by polycondensation of dibasic acid and diol. It contains ester groups in the molecular chain, which can significantly improve the strength and hardness of the foam. It also has good heat resistance and chemical corrosion resistance, so that the foam can still maintain good performance under high temperature and chemical substances. The high flexibility and hydrolysis resistance of polyether DL-4000 complement the high strength and hardness of PEA-3000. This combination can make the foam have good elasticity and softness while meeting certain strength requirements.

[0012] Furthermore, in the above-mentioned low thermal conductivity flame-retardant polyurethane foam, the mass ratio of the polyether polyol to the polyester polyol is 2:1 to 3:1.

[0013] Furthermore, in the above-mentioned low thermal conductivity flame-retardant polyurethane foam, the mass ratio of toluene diisocyanate to diphenylmethane diisocyanate is 1:1~2:1.

[0014] TDI has high reactivity and can react quickly with polyols to start the foaming process quickly; while MDI has relatively low reactivity and can continue to play a role in the later stage of the reaction, making the reaction more sufficient and stable. This combination can accurately control the reaction speed by adjusting the ratio of the two, avoiding excessive reaction leading to uneven foam structure or excessive reaction affecting production efficiency. In addition, during the reaction process, TDI can provide an appropriate amount of cross-linking points to give the foam a certain elasticity and flexibility, while MDI can increase the cross-linking density of the foam, improve the strength and hardness of the foam, and thus optimize the cross-linking density of the foam.

[0015] In addition, MDI has high thermal stability and can improve the performance of foam in high temperature environment. When TDI and MDI are used in combination, MDI can make up for the shortcomings of TDI in thermal stability, making the foam less likely to decompose and deform under high temperature conditions. In addition, TDI has certain volatility and toxicity, which may cause harm to the human body and the environment during production and use. The volatility and toxicity of MDI are relatively low. By using TDI and MDI in combination, the amount of TDI can be appropriately reduced while ensuring the performance of the foam, thereby reducing the emission of volatile organic compounds and potential risks to human health, meeting environmental protection and safety requirements.

[0016] Furthermore, in the above-mentioned low thermal conductivity flame retardant polyurethane foam, the foaming agent is a compound of a physical foaming agent and a chemical foaming agent, the physical foaming agent is cyclopentane, and the chemical foaming agent is water.

[0017] Preferably, the mass ratio of the physical foaming agent to the chemical foaming agent is 2:1 to 3:1.

[0018] Cyclopentane has a good foaming effect and can produce a uniform pore structure, while water reacts with isocyanate to generate carbon dioxide gas, which further assists foaming and can also play a role in adjusting the hardness of the foam.

[0019] Furthermore, in the above-mentioned low thermal conductivity flame-retardant polyurethane foam, the amine catalyst is A-33 (triethylenediamine), DMCHA (dimethylcyclohexylamine), BDMA (N,N-dimethylbenzylamine), TMPDA (N,N,N',N'-tetramethylpropylenediamine), and the tin catalyst is DBTDL (dibutyltin dilaurate), T-9 (stannous octoate), DBTDA (dibutyltin diacetate), and DBTM (dibutyltin maleate).

[0020] Preferably, the amine catalyst is DMCHA, the tin catalyst is T-9, and the mass ratio of the amine catalyst to the tin catalyst is 1:1 to 2:1.

[0021] Dimethylcyclohexylamine has moderate catalytic activity, can effectively promote the formation reaction of polyurethane, and has good dispersibility in foam. T-9 has high catalytic activity and selectivity, can promote the formation reaction of polyurethane, and has a certain improvement effect on the performance of foam. When DMCHA is compounded with T-9, DMCHA provides moderate catalytic activity, and T-9 can further improve the reaction efficiency and improve the physical properties of foam.

[0022] Furthermore, in the above-mentioned low thermal conductivity flame-retardant polyurethane foam, the phosphorus-based flame retardant is one or a combination of multiple selected from ammonium polyphosphate, triphenyl phosphate, tricresyl phosphate, and phosphazene flame retardants, and the nitrogen-based flame retardant is one or a combination of multiple selected from melamine, melamine cyanurate, urea, and dicyandiamide.

[0023] Preferably, the phosphorus-based flame retardant is ammonium polyphosphate or phosphazene flame retardant, and the nitrogen-based flame retardant is dicyandiamide. The mass ratio of ammonium polyphosphate: hexaphenoxy cyclotriphosphazene: dicyandiamide is (3-5): (2-4): (1-2).

[0024] More preferably, the phosphorus-based flame retardant is hexaphenoxycyclotriphosphazene.

[0025] There is a synergistic effect between ammonium polyphosphate, hexaphenoxy cyclotriphosphazene and dicyandiamide. Ammonium polyphosphate provides acid and gas sources to promote the formation of the carbon layer; hexaphenoxy cyclotriphosphazene captures free radicals to inhibit the propagation of the combustion reaction chain; dicyandiamide supplements non-flammable gas and dilutes the concentration of combustible gas. The three work together to make the flame retardant effect far better than that of a single flame retardant. This composite flame retardant produces relatively less smoke and toxic gases during combustion.

[0026] Furthermore, in the above-mentioned low thermal conductivity flame-retardant polyurethane foam, the surfactant is one or a combination of multiple of silicone surfactants, polyether-modified siloxane surfactants, fluorocarbon surfactants, and non-ionic surfactants.

[0027] Furthermore, in the above-mentioned low thermal conductivity flame-retardant polyurethane foam, the anti-aging agent is one or a combination of multiple types of hindered phenol anti-aging agents, phosphite anti-aging agents, ultraviolet absorbers, and light stabilizers.

[0028] The present invention also relates to a method for preparing the low thermal conductivity flame retardant polyurethane foam, comprising the following steps: S1 pretreatment: polyether polyol and polyester polyol are mixed evenly, and vacuum dehydration treatment is performed at 100-120°C for 2-3h to obtain a pretreated polyol mixture; flame retardant, catalyst, foaming agent, surfactant, and anti-aging agent are added to the pretreated polyol mixture, and stirred evenly at 50-60°C to form a uniform mixed solution; S2 foaming reaction: preheat the isocyanate at 40-50°C, slowly add it into the above mixed solution, and stir it at a high speed of 500-800 rpm for 3-5 min. After fully mixing, obtain the foaming material; S3 molding and aging: pouring the foaming material into a pre-prepared mold, naturally foaming and molding at room temperature to obtain a foam blank; placing the foam blank in an oven, aging at 80-100° C. for 24-48 hours to obtain an aged foam; S4 treatment: Cut and trim the matured foam to the required size and shape.

[0029] Compared with the prior art, the present invention has the following beneficial effects: (1) The low thermal conductivity flame-retardant polyurethane foam disclosed in the present invention adopts a combination of polyether polyol and polyester polyol as the polyol system. The molecular structure of polyether polyol contains more ether bonds, and its molecular chain is relatively soft and has good flexibility, which can give the foam a certain elasticity and resilience. Polyester polyol can improve the strength and hardness of the foam. This combination makes the internal structure of the foam more stable, reduces the heat conduction path between molecules, and helps to reduce thermal conductivity; the compound use of physical foaming agent cyclopentane and chemical foaming agent water can produce a uniform and fine pore structure. Cyclopentane vaporizes during the foaming process to form a large number of evenly distributed bubbles, providing a good insulating air layer for the foam. Water reacts with isocyanate to generate carbon dioxide gas, which further supplements the foaming gas and makes the pore structure more perfect. These uniform and fine bubbles can effectively prevent the conduction of heat and help to reduce thermal conductivity; (2) The low thermal conductivity flame-retardant polyurethane foam disclosed in the present invention, the combination of phosphorus-based flame retardant and nitrogen-based flame retardant can significantly improve the flame retardant properties of the foam through the synergistic effect of gas phase flame retardancy and condensed phase flame retardancy; the combination of polyether polyol and polyester polyol and the mixed isocyanate system of toluene diisocyanate and diphenylmethane diisocyanate also help to improve the flame retardant properties of the foam to a certain extent. These raw materials can form a relatively stable carbonized structure during the combustion process, and synergistically act with the flame retardant to further enhance the flame retardant effect of the foam; (3) The low thermal conductivity flame retardant polyurethane foam disclosed in the present invention, the combination of polyether polyol and polyester polyol, the combination of toluene diisocyanate and diphenylmethane diisocyanate, can make the foam have good flexibility, hydrolysis resistance, strength and hardness; the addition of surfactant can improve the surface properties of the foam, reduce the surface tension of the foam, make the foam surface smoother and flatter, and improve the waterproof and oil-proof properties of the foam; the anti-aging agent can improve the aging resistance of the foam; (4) The method for preparing the low thermal conductivity flame-retardant polyurethane foam disclosed in the present invention has reasonable preparation steps, which are simple and controllable and have high flexibility, can be used for large-scale production, and has good economic efficiency. DETAILED DESCRIPTION

[0030] The following examples 1, 2, and 3 are combined with specific experimental data to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work belong to the protection scope of the present invention. The main raw materials of Examples 1-3: polyether DL-4000D (purchased from Shandong Bluestar Dongda Chemical Co., Ltd.), PEA-3000 (purchased from Yantai Wanhua Chemical Co., Ltd., with a molecular weight of 3000, a hydroxyl value of 34-42 mgKOH / g, waxy, and a viscosity (75°) of 1600~1800 mPa·s), toluene diisocyanate (purchased from Yantai Wanhua Chemical Co., Ltd., with a content of 99.5%), and diphenylmethane diisocyanate (purchased from Yantai Wanhua Chemical Co., Ltd. WANNATE MDI-100); others are commercially available.

[0031] Embodiments 1-3 provide a flame retardant polyurethane foam with low thermal conductivity and a preparation method.

[0032] Example 1 The polyurethane foam of Example 1 comprises the following raw materials in parts by weight: Polyether DL-4000D 30 parts; PEA-3000 15 parts; Toluene diisocyanate 15 parts; 10 parts of diphenylmethane diisocyanate; 4 parts of cyclopentane; 2 parts water; DMCHA 0.5 parts; T-9 0.5 parts; 6 parts of ammonium polyphosphate; 6 parts of hexaphenoxy cyclotriphosphazene; 2 parts of dicyandiamide; Surfactant L-580 0.5 part; 1 part of antioxidant 1010; Ultraviolet absorber UV-531 0.5 parts.

[0033] The preparation of the urethane foam of Example 1 comprises the following steps: S1 pretreatment: polyether DL-4000D and PEA-3000 were mixed evenly, and vacuum dehydrated at 110°C for 3 hours to obtain a pretreated polyol mixture; cyclopentane, water, DMCHA, T-9, ammonium polyphosphate, hexaphenoxy cyclotriphosphazene, dicyandiamide, surfactant L-580, antioxidant 1010, and ultraviolet absorber UV-531 were added to the pretreated polyol mixture, and stirred evenly at 50°C to form a uniform mixed solution; S2 foaming reaction: preheat toluene diisocyanate and diphenylmethane diisocyanate at 45°C, slowly add them into the above mixed solution, and stir at a high speed of 500-800 rpm for 3-5 min. After fully mixing, obtain a foaming material; S3 molding and aging: pouring the foaming material into a pre-prepared mold, naturally foaming and molding at room temperature to obtain a foam blank; placing the foam blank in an oven, aging at 100° C. for 24 to 48 hours to obtain an aged foam; S4 treatment: Cut and trim the matured foam to the required size and shape.

[0034] Example 2 The polyurethane foam of Example 2 comprises the following raw materials in parts by weight: Polyether DL-4000D 30 parts; PEA-3000 10 parts; Toluene diisocyanate 12 parts; 12 parts of diphenylmethane diisocyanate; 4 parts of cyclopentane; 2 parts water; DMCHA 0.5 parts; T-9 0.5 parts; 6 parts of ammonium polyphosphate; 6 parts of hexaphenoxy cyclotriphosphazene; 2 parts of dicyandiamide; Surfactant L-580 0.5 part; 1 part of antioxidant 1010; Ultraviolet absorber UV-531 0.5 parts.

[0035] The preparation of the urethane foam of Example 2 comprises the following steps: S1 pretreatment: polyether DL-4000D and PEA-3000 were mixed evenly, and vacuum dehydrated at 110°C for 3 hours to obtain a pretreated polyol mixture; cyclopentane, water, DMCHA, T-9, ammonium polyphosphate, hexaphenoxy cyclotriphosphazene, dicyandiamide, surfactant L-580, antioxidant 1010, and ultraviolet absorber UV-531 were added to the pretreated polyol mixture, and stirred evenly at 50°C to form a uniform mixed solution; S2 foaming reaction: preheat toluene diisocyanate and diphenylmethane diisocyanate at 45°C, slowly add them into the above mixed solution, and stir at a high speed of 500-800 rpm for 3-5 min. After fully mixing, obtain a foaming material; S3 molding and aging: pouring the foaming material into a pre-prepared mold, naturally foaming and molding at room temperature to obtain a foam blank; placing the foam blank in an oven, aging at 100° C. for 24 to 48 hours to obtain an aged foam; S4 treatment: Cut and trim the matured foam to the required size and shape.

[0036] Example 3 The urethane foam of Example 3 comprises the following raw materials in parts by weight: Polyether DL-4000D 30 parts; PEA-3000 15 parts; Toluene diisocyanate 20 parts; 10 parts of diphenylmethane diisocyanate; 4 parts of cyclopentane; 2 parts water; DMCHA 0.5 parts; T-9 0.5 parts; 8 parts of ammonium polyphosphate; 8 parts of hexaphenoxy cyclotriphosphazene; 4 parts of dicyandiamide; Surfactant L-580 0.5 part; 1 part of antioxidant 1010; Ultraviolet absorber UV-531 0.5 parts.

[0037] The preparation of the urethane foam of Example 3 comprises the following steps: S1 pretreatment: polyether DL-4000D and PEA-3000 were mixed evenly, and vacuum dehydrated at 110°C for 3 hours to obtain a pretreated polyol mixture; cyclopentane, water, DMCHA, T-9, ammonium polyphosphate, hexaphenoxy cyclotriphosphazene, dicyandiamide, surfactant L-580, antioxidant 1010, and ultraviolet absorber UV-531 were added to the pretreated polyol mixture, and stirred evenly at 50°C to form a uniform mixed solution; S2 foaming reaction: preheat toluene diisocyanate and diphenylmethane diisocyanate at 45°C, slowly add them into the above mixed solution, and stir at a high speed of 500-800 rpm for 3-5 min. After fully mixing, obtain a foaming material; S3 molding and aging: pouring the foaming material into a pre-prepared mold, naturally foaming and molding at room temperature to obtain a foam blank; placing the foam blank in an oven, aging at 100° C. for 24 to 48 hours to obtain an aged foam; S4 treatment: Cut and trim the matured foam to the required size and shape.

[0038] The urethane foams prepared in Examples 1-3 were subjected to performance testing.

[0039] The thermal conductivity was measured using a thermal conductivity meter, and the results are shown in Table 1.

[0040] The flame retardant properties were measured using the UL94 vertical burning test and oxygen index. The test results are shown in Table 1.

[0041] Table 1 Compression resilience test: A weight of 2 kg was applied to each of Examples 1-3 of size 3 mm×3 mm×2 mm at room temperature, and the pressure was released after maintaining for 1 hour, and then the rebound height of Examples 1-3 was measured.

[0042] Examples 1-3 can all rebound to about 70% of the original thickness after 30 seconds of pressure release, can rebound to about 90% of the original thickness after 1 minute of pressure release, and can completely rebound to the initial thickness in about 10 minutes.

[0043] Weather resistance test: Examples 1-3 with a size of 3 mm×3 mm×2 mm were placed in an environment of 85° C. and 85% relative humidity for 3 days, and then cooled to room temperature before being subjected to a compression resilience test.

[0044] After aging, Examples 1-3 can rebound to about 50% of the original thickness after 30 seconds of pressure release, can rebound to about 70% of the original thickness after 1 minute of pressure release, and can completely rebound to the initial thickness in about 20 minutes.

[0045] It can be seen from the above that Examples 1-3 prepared by the technical solution of the present invention have low thermal conductivity and flame retardant properties, as well as good physical and mechanical properties, and can meet the needs of different application scenarios.

[0046] The present invention has many specific application paths, and the above is only a preferred embodiment of the present invention. It should be pointed out that the above embodiments are only used to illustrate the present invention, and are not used to limit the protection scope of the present invention. For those of ordinary skill in the art, several improvements can be made without departing from the principle of the present invention, and these improvements should also be regarded as the protection scope of the present invention.

Claims

1. A low thermal conductivity flame retardant polyurethane foam, characterized in that: The invention comprises the following raw materials in parts by weight: 30-50 parts of polyol, wherein the polyol is a combination of polyether polyol and polyester polyol; 20-30 parts of isocyanate, wherein the isocyanate is a combination of toluene diisocyanate and diphenylmethane diisocyanate; 3~8 parts of foaming agent; 0.5-1.5 parts of a catalyst, wherein the catalyst is a combination of an amine catalyst and a tin catalyst; 10 to 20 parts of a flame retardant, wherein the flame retardant is a combination of a phosphorus-based flame retardant and a nitrogen-based flame retardant; Surfactant 0~1 part; Anti-aging agent 0~2 parts.

2. The low thermal conductivity flame retardant polyurethane foam according to claim 1, characterized in that: The polyether polyol is one or more of polyether DL-4000D, polyether N330, polyether EP-3600, and polyether MN-500; the polyester polyol is one or more of PEA-3000, PBA-2000, PCL-2000, and PTA-3000.

3. The low thermal conductivity flame retardant polyurethane foam according to claim 2, characterized in that: The mass ratio of the polyether polyol to the polyester polyol is 2:1 to 3:

1.

4. The low thermal conductivity flame retardant polyurethane foam according to claim 1, characterized in that: The mass ratio of the toluene diisocyanate to diphenylmethane diisocyanate is 1:1 to 2:

1.

5. The low thermal conductivity flame retardant polyurethane foam according to claim 1, characterized in that: The foaming agent is a compound of a physical foaming agent and a chemical foaming agent, wherein the physical foaming agent is cyclopentane and the chemical foaming agent is water.

6. The low thermal conductivity flame retardant polyurethane foam according to claim 1, characterized in that: The amine catalyst is one or more of A-33, DMCHA, BDMA, TMPDA, and the tin catalyst is one or more of DBTDL, T-9, DBTDA, and DBTM.

7. The low thermal conductivity flame retardant polyurethane foam according to claim 1, characterized in that: The phosphorus-based flame retardant is one or a combination of ammonium polyphosphate, triphenyl phosphate, tricresyl phosphate, and phosphazene flame retardants, and the nitrogen-based flame retardant is one or a combination of melamine, melamine cyanurate, urea, and dicyandiamide.

8. The low thermal conductivity flame retardant polyurethane foam according to claim 1, characterized in that: The surfactant is one or a combination of silicone surfactants, polyether-modified siloxane surfactants, fluorocarbon surfactants, and non-ionic surfactants.

9. The low thermal conductivity flame retardant polyurethane foam according to claim 1, characterized in that: The anti-aging agent is one or a combination of hindered phenol anti-aging agents, phosphite anti-aging agents, ultraviolet absorbers, and light stabilizers.

10. The method for preparing the low thermal conductivity flame retardant polyurethane foam according to any one of claims 1 to 9, characterized in that: The steps include: S1 pretreatment: polyether polyol and polyester polyol are mixed evenly, and vacuum dehydration treatment is performed at 100-120°C for 2-3h to obtain a pretreated polyol mixture; flame retardant, catalyst, foaming agent, surfactant, and anti-aging agent are added to the pretreated polyol mixture, and stirred evenly at 50-60°C to form a uniform mixed solution; S2 foaming reaction: preheat the isocyanate at 40-50°C, slowly add it into the above mixed solution, and stir it at a high speed of 500-800 rpm for 3-5 min. After fully mixing, obtain the foaming material; S3 molding and aging: pouring the foaming material into a pre-prepared mold, naturally foaming and molding at room temperature to obtain a foam blank; placing the foam blank in an oven, aging at 80-100° C. for 24-48 hours to obtain an aged foam; S4 treatment: Cut and trim the matured foam to the required size and shape.

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