Organic montmorillonite modified soft melamine foam material and preparation method thereof

Abstract

The invention relates to the technical field of materials, in particular to an organic montmorillonite modified soft melamine foam material and a preparation method thereof. The organic montmorillonite modified melamine foam disclosed by the invention is mainly prepared from the following raw materials in parts by mass: 100 parts of organic montmorillonite modified melamine-formaldehyde pre-polycondensate, 0.5 to 10 parts of a surfactant, 2 to 20 parts of a foaming agent, 2 to 15 parts of a catalyst, 0 to 5 parts of an auxiliary agent and 0 to 30 parts of water. The organic montmorillonite modified melamine foam disclosed by the invention not only has excellent mechanical properties, but also has excellent flame retardant property and thermal stability. The preparation method of the organic montmorillonite modified melamine foam is simple, raw materials are easy to obtain, and the organic montmorillonite modified melamine foam has the potential of large-scale popularization and application.

Description

Technical Field

[0001] This invention relates to the field of materials technology, and in particular to organomontmorillonite-modified flexible melamine foam materials and their preparation methods. Background Technology

[0002] Melamine foam is a flame-retardant foam plastic made primarily from melamine-formaldehyde resin using a microwave foaming process. It boasts an open-cell ratio exceeding 99% and an internal porous structure. In addition to the basic properties of general-purpose flexible foams, it also features low density, low thermal conductivity, excellent flame retardancy, good resistance to damp heat, thermal insulation, and sound absorption. As a flexible foam with superior comprehensive performance, melamine foam has significant application value in civil construction, industry, transportation, aerospace, military, daily chemicals, and electronic information fields. It is particularly suitable for environments with strict requirements for flame retardancy, high temperature resistance, and low-frequency noise absorption, making it a promising new environmentally friendly material for the 21st century.

[0003] As early as the 1960s, patents related to melamine foam were published, such as US3063953, US3093600, and US3160596. These patents described the heat resistance and flame retardant properties of melamine foam and disclosed its preparation methods, providing detailed discussions on key process parameters such as material ratios and reaction conditions. In the late 1970s and early 1980s, BASF successively published a series of patents, including US4334971, US4511678, US4540717, US4530940, US4666948, and US4885206. These patents systematically explain the preparation principle and process of melamine foam. Its main raw material is melamine-formaldehyde resin, which can be compounded by adding alkyl-substituted melamine, urea, polyurethane, sulfonamide, phenol and its derivatives, acetaldehyde, benzaldehyde, acrolein, glyoxal and other modifiers. Then, it is mixed and emulsified with emulsifier, foaming agent, curing agent and other additives, and then microwave foamed, cured and dried to finally obtain foam material with good flame retardant, sound absorption and lightweight properties.

[0004] However, traditional flexible melamine foam materials are mostly made from melamine-formaldehyde prepolymers, which are cross-linked and cured through methylene or dimethylene ether bonds. Because the methylene groups are connected to triazine rings with large steric hindrance at both ends, and the multiple methylene groups and triazine rings are arranged alternately, the cured resin has high hardness and poor flexibility, resulting in low material strength and high brittleness.

[0005] Therefore, toughening modification has become one of the research hotspots in the field of melamine foam. US Patent No. 5162487 attempts to improve the flexibility of melamine-formaldehyde resin by introducing hydroxyl-containing alkoxy groups to replace part of the melamine, but the effect is limited. Chinese Patent No. CN101735555A discloses a "highly flexible melamine-formaldehyde foam material and its preparation method," which uses a polyhydroxy compound to prepolymerize melamine-formaldehyde resin and introduces long flexible chains between triazine rings to reduce crosslinking density, thereby improving foam flexibility. However, the addition of the modifier introduces flammable components, leading to a decrease in the foam's flame retardant properties. Chinese Patent No. CN104277416A proposes using polyvinyl acetal to modify melamine resin, supplemented with surfactants, foaming agents, and curing agents, and then preparing modified foam through mixing and foaming. Although this method can reduce the sludge shedding rate and improve flexibility, the introduction of polyvinyl acetal impairs the foam's thermal stability and flame retardancy. Chinese patent CN103665755A describes a method that involves pre-synthesizing a phosphorus-containing polysiloxane modifier, then copolymerizing it with melamine and formaldehyde to prepare a modified resin, which is then foamed to obtain melamine foam. While this method can partially alleviate the problem of reduced flame retardant performance due to toughening, the toughening effect is still not ideal. Furthermore, the synthesis process of the modifier is demanding, requiring nitrogen protection and cooling to 0°C. Post-processing involves vacuum distillation to remove solvents such as tetrahydrofuran, xylene, and dichloromethane, making the process complex and unsuitable for large-scale production.

[0006] In general, while existing technologies can improve certain properties of melamine foam in some aspects, it is still difficult to simultaneously enhance mechanical properties while maintaining flame retardancy and ease of processing. Therefore, developing a preparation method that can effectively improve the mechanical properties of melamine foam, maintain its excellent flame retardant characteristics, and is suitable for large-scale production is of great significance for expanding the application fields of melamine foam.

[0007] Furthermore, on the one hand, there are differences in understanding among those skilled in the art; on the other hand, the inventors studied a large number of documents and patents when making this invention, but due to space limitations, not all details and contents were listed in detail. However, this does not mean that the present invention does not possess the features of these prior art. On the contrary, the present invention already possesses all the features of the prior art, and the applicant reserves the right to add relevant prior art to the background art. Summary of the Invention

[0008] This invention relates to the field of materials technology, and in particular to organomontmorillonite-modified flexible melamine foam materials and their preparation methods.

[0009] To address the aforementioned technical problems, one objective of this invention is to provide an organomontmorillonite-modified flexible melamine foam material, comprising the following raw materials in parts by weight: The mixture consists of 100 parts of organomontmorillonite-modified melamine-formaldehyde prepolymer, 0.5-10 parts of surfactant, 2-20 parts of foaming agent, 2-15 parts of catalyst, 0-5 parts of additives, and 0-30 parts of water.

[0010] According to a preferred embodiment, the organo-montmorillonite is one or more of the following: di(hydroxyethyl)methyldodecylammonium chloride-modified montmorillonite, trimethyldodecylammonium chloride-modified montmorillonite, trimethylhexadecylammonium chloride-modified montmorillonite, trimethyloctadecylammonium chloride-modified montmorillonite, dimethylbenzyloctadecylammonium chloride-modified montmorillonite, dimethylbisoctadecylammonium chloride-modified montmorillonite, and trihydroxyoctadecylammonium chloride-modified montmorillonite. Preferably, the organo-montmorillonite is one or more of the following: di(hydroxyethyl)methyldodecylammonium chloride-modified montmorillonite, trimethyloctadecylammonium chloride-modified montmorillonite, or dimethylbenzyloctadecylammonium chloride-modified montmorillonite.

[0011] According to a preferred embodiment, the surfactant is a group consisting of anionic-cationic surfactant complexes, anionic-amphoteric surfactant complexes, and anionic-cationic surfactant complexes.

[0012] Preferably, the anionic surfactant is one or more of the following: fatty alcohol polyoxyethylene ether sulfate, polyether carboxylate, alkylbenzene sulfonate, alkyl sulfonate, succinate sulfonate, higher fatty amide sulfonate, fatty acid ester alkyl sulfonate, fatty alcohol sulfate, fatty alcohol phosphate, and fatty alcohol polyoxyethylene ether phosphate. More preferably, the anionic surfactant is an alkylbenzene sulfonate or a fatty alcohol polyoxyethylene ether sulfate.

[0013] Preferably, the amphoteric surfactant is one or more of carboxybetaine-type amphoteric surfactants, sulfonate betaine-type amphoteric surfactants, and amino acid-type amphoteric surfactants. More preferably, it is a carboxybetaine-type amphoteric surfactant.

[0014] Preferably, the cationic surfactant is one of alkyl quaternary ammonium salt, ether quaternary ammonium salt, and amide quaternary ammonium salt. More preferably, the cationic surfactant is an alkyl quaternary ammonium salt.

[0015] Preferably, the nonionic surfactant is one or more selected from fatty alcohol polyoxyethylene ether, alkylphenol polyoxyethylene ether, polyoxyethylene alkyl amide, and fatty acid polyoxyethylene ester. More preferably, the nonionic surfactant is fatty alcohol polyoxyethylene ether or alkylphenol polyoxyethylene ether.

[0016] According to a preferred embodiment, the foaming agent is one or more of n-pentane, cyclopentane, n-hexane, cyclohexane, petroleum ether, 1,2-dichlorotetrafluoroethane, and 1,2,2-trichloro-1,1-difluoroethane, preferably one or more of n-pentane, cyclopentane, and 1,2,2-trichloro-1,1-difluoroethane.

[0017] According to a preferred embodiment, the catalyst is one or more organic or inorganic acids. Preferably, the catalyst is one or more of formic acid, acetic acid, butyric acid, oxalic acid, malonic acid, succinic acid, glutaric acid, toluenesulfonic acid, acrylic acid, hydrochloric acid, sulfuric acid, phosphoric acid, and nitric acid. More preferably, the catalyst is one or two of formic acid, acetic acid, and sulfuric acid.

[0018] According to a preferred embodiment, the additive is one or more of colorants, UV stabilizers, and anti-aging agents.

[0019] To address the aforementioned technical problems, one objective of this invention is to provide a method for preparing organomontmorillonite-modified flexible melamine foam material, comprising the following steps: S1. Organic montmorillonite was added to a formaldehyde aqueous solution and stirred at 80℃~90℃ for 1 h. Paraformaldehyde was added, and the temperature was raised to 95℃~100℃. Melamine was added, and the reaction was carried out at a constant temperature of 95℃~100℃. The reaction progress was monitored by cloud point. When the cloud point reached 10~25℃, sodium bisulfite or aminosulfonic acid was added, and the reaction was continued at 95℃~100℃. When the desired cloud point was reached, the heating was stopped and the temperature was quickly lowered to below 40℃ to obtain the montmorillonite-modified melamine-formaldehyde resin prepolymer. S2 is prepared by uniformly mixing organomontmorillonite-modified melamine-formaldehyde prepolymer with surfactant, foaming agent, catalyst and water to form a homogeneous foaming emulsion, and adding auxiliary agents as needed; S3 The foaming emulsion obtained from S2 is foamed for 5 min to 10 min under microwave action at an internal temperature of 50℃~150℃ to obtain a semi-finished melamine foam material. S4 The semi-finished melamine foam material obtained from S3 is subjected to high-temperature annealing with hot air at 150℃~300℃ for 30min~60min to obtain organomontmorillonite modified melamine foam material.

[0020] According to a preferred embodiment, the molar ratio of melamine to formaldehyde is 1:1 to 1:6. Preferably, the molar ratio of melamine to formaldehyde is 1:1.5 to 1:3.5.

[0021] According to a preferred embodiment, the mass of organomontmorillonite added is 1%-10% of the mass of melamine. Preferably, the mass of organomontmorillonite added is 1%-5% of the mass of melamine.

[0022] According to a preferred embodiment, the method for preparing organomontmorillonite includes the following steps: Alkyl ammonium chloride is mixed with saturated hydrochloric acid and stirred until homogeneous, then introduced into a sodium montmorillonite suspension; After stirring at high speed for 5 minutes, a white precipitate appeared. The precipitate was filtered and then washed with deionized water until no Cl was found. - (Use Ag) + (Test), then dry at 100℃~105℃ to constant weight, pulverize and sieve to obtain organomontmorillonite powder.

[0023] One of the objectives of this invention is to provide the use of the above-mentioned organomontmorillonite-modified soft melamine foam material or the organomontmorillonite-modified soft melamine foam material prepared by the above-mentioned method for preparing heat insulation, thermal insulation or noise reduction materials.

[0024] The organomontmorillonite-modified melamine foam material of this invention not only possesses excellent mechanical properties but also exhibits superior flame retardancy and thermal stability. Compared with existing technologies, the beneficial effects of this invention are as follows: (1) Organic montmorillonite was used as a modifier to modify melamine foam material. Organic montmorillonite and melamine-formaldehyde precondensate were used to form a melamine-formaldehyde precondensate / montmorillonite composite material. Montmorillonite, as a layered silicate, has a large aspect ratio and a thickness of only 1 nm. Thanks to this special geometry, montmorillonite has an extremely high specific surface area. Theoretically, if 1 g of montmorillonite is fully unfolded, its area is 700 m². 2 When such layers are uniformly dispersed at the nanoscale in a polymer matrix, they form a typical "nanocomposite" structure.

[0025] The highly dispersed montmorillonite sheets endow nanocomposites formed with polymer materials with excellent gas barrier effects. The silicate sheets dispersed within the material matrix act as baffles, forcing gas diffusion to bypass these impermeable sheets and proceed along a tortuous path. This "maze effect" significantly lengthens the gas diffusion path, effectively reducing the gas diffusion coefficient and permeation rate.

[0026] (2) Monomers are inserted between organic montmorillonite sheets, and modified melamine-formaldehyde prepolymers are prepared by in-situ intercalation polymerization. These prepolymers are then used as raw materials to prepare melamine foam materials, forming polymer / layered silicate nanocomposite materials.

[0027] (3) The dispersion of layered silicates in polymer materials enables the formation of a uniform carbonized layer during combustion, which improves the flame retardant properties of the materials.

[0028] (4) The modifier of this invention is a conventional industrial product, and the modified resin has a simple synthesis process and has the potential for large-scale promotion and application. Detailed Implementation

[0029] In the description of this invention, terminology is used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly defined.

[0030] Unless otherwise specified, the experimental methods used in the following examples are all conventional methods; the materials, reagents or instruments used, unless otherwise specified by the manufacturer, are all commercially available reagents and materials; the conditions not specified in the examples are all carried out according to conventional conditions or conditions recommended by the manufacturer. At the same time, the present invention does not limit the source of the raw materials used. Unless otherwise specified, the raw materials used in the present invention are all commercially available products in this technical field.

[0031] Preparation of organomontmorillonite: 200 g of sodium montmorillonite was dispersed in 4000 mL of distilled water and stirred for a certain period of time to form a stable suspension. Then, 66.2 g of di(hydroxyethyl)methyldodecyl ammonium chloride was mixed with 23 mL of saturated hydrochloric acid to form a homogeneous solution, which was then poured into the montmorillonite suspension. Under high-speed stirring, a white precipitate appeared after 5 minutes. This precipitate was filtered and washed with deionized water until Cl... - (Use Ag) + (Test), then dry at 100℃~105℃ to constant weight, pulverize and sieve to obtain di(hydroxyethyl)methyldodecylammonium chloride modified montmorillonite powder (abbreviated as C12-MMT).

[0032] The process of modifying montmorillonite with other types of organic modifiers is the same as the above process, except that 71.8 g of montmorillonite modified with trimethyloctadecyl ammonium chloride and 89.2 g of montmorillonite modified with dimethylbenzyloctadecyl ammonium chloride are respectively mixed with 23 mL of saturated hydrochloric acid. The resulting organic montmorillonite is montmorillonite modified with trimethyloctadecyl ammonium chloride (abbreviated as C18a-MMT) and montmorillonite modified with dimethylbenzyloctadecyl ammonium chloride (abbreviated as C18b-MMT).

[0033] The organomontmorillonite-modified flexible melamine foam material involved in this invention not only possesses excellent mechanical properties but also exhibits superior flame retardancy and thermal stability. Furthermore, the preparation method is simple, the raw materials are readily available, and it has the potential for large-scale application.

[0034] Example 1 Synthesis of C12-MMT modified melamine-formaldehyde prepolymer: 17.5 g of C12-MMT was added to 1000 g of formaldehyde aqueous solution (37%) and stirred at a constant temperature of 80℃~90℃ for 1 h. Then, 130 g of paraformaldehyde was added, and the temperature was raised to 95℃~100℃. Next, 700 g of melamine was added, and the reaction was continued at 95℃~100℃, with the turbidity point monitored as the reaction progress. When the turbidity point reached 10℃~15℃, 70 g of sodium bisulfite was added, and the reaction continued at 95℃~100℃. Heating was stopped when the desired turbidity point was reached, and the temperature was rapidly lowered to below 40℃ to obtain the C12-MMT-modified melamine-formaldehyde prepolymer.

[0035] 300 g of C12-MMT modified melamine-formaldehyde prepolymer, 4.8 g of sodium dodecylbenzenesulfonate, 1.2 g of lauryl alcohol polyoxyethylene ether, 30 g of n-pentane, 15 g of cyclopentane, 15 g of acetic acid, and 5 g of water were first mixed at low speed and then at high speed until homogeneous, resulting in a homogeneous foaming emulsion. The foaming emulsion was then foamed for 5 min under microwave irradiation at an internal temperature of 95°C to obtain a semi-finished melamine foam material. Finally, the semi-finished product was annealed in hot air at 240°C for 30 min to obtain the finished C12-MMT modified melamine foam material.

[0036] Example 2 Synthesis of C18a-MMT modified melamine-formaldehyde prepolymer: 32 g of C18a-MMT was added to 855 g of a 37% formaldehyde aqueous solution and stirred at a constant temperature of 80℃~90℃ for 1 h. 160 g of paraformaldehyde was added, and the temperature was raised to 95℃~100℃. 800 g of melamine was then added, and the reaction was continued at 95℃~100℃, with the turbidity point monitored as the reaction progress. When the turbidity point reached 15℃~20℃, 60 g of aminosulfonic acid was added, and the reaction continued at 95℃~100℃. Heating was stopped when the desired turbidity point was reached, and the temperature was rapidly lowered to below 40℃ to obtain the C18a-MMT-modified melamine-formaldehyde prepolymer.

[0037] 300 g of C18a-MMT modified melamine-formaldehyde prepolymer, 9.0 g of sodium dodecylbenzenesulfonate, 3.0 g of lauryl alcohol polyoxyethylene ether, 40 g of n-pentane, 10 g of 1,2-difluoro-1,1,2-trichloroethane, 5 g of acetic acid, 15 g of formic acid, and 10 g of water were first mixed at low speed and then at high speed until homogeneous, resulting in a homogeneous foaming emulsion. The foaming emulsion was then foamed for 5 min under microwave irradiation at an internal temperature of 95°C to obtain a semi-finished melamine foam material. Finally, the semi-finished product was annealed in hot air at 240°C for 30 min to obtain the finished C18a-MMT modified melamine foam material.

[0038] Example 3 Synthesis of C18b-MMT modified melamine-formaldehyde prepolymer: 22.4 g of C18b-MMT was added to 970 g of formaldehyde aqueous solution (37%), and stirred at a constant temperature of 80℃~90℃ for 1 h. 175 g of paraformaldehyde was added, and the temperature was raised to 95℃~100℃. 800 g of melamine was added, and the reaction was continued at 95℃~100℃, with the turbidity point monitored as the reaction progress. When the turbidity point reached 15℃~20℃, 40 g of sodium bisulfite was added, and the reaction continued at 95℃~100℃. Heating was stopped when the desired turbidity point was reached, and the temperature was rapidly lowered to below 40℃ to obtain the C18b-MMT-modified melamine-formaldehyde prepolymer.

[0039] 300 g of C18b-MMT modified melamine-formaldehyde prepolymer, 6.0 g of sodium dodecylbenzenesulfonate, 3.0 g of dodecyl betaine, 35 g of n-pentane, 20 g of 1,2-difluoro-1,1,2-trichloroethane, 10 g of acetic acid, 3 g of formic acid, and 12 g of water were first mixed at low speed and then at high speed until homogeneous, resulting in a homogeneous foaming emulsion. The foaming emulsion was then foamed for 5 min under microwave irradiation at an internal temperature of 80°C to obtain a semi-finished melamine foam material. Finally, the semi-finished product was annealed in hot air at 240°C for 30 min to obtain the finished C18a-MMT modified melamine foam material.

[0040] Comparative Example 1 The comparative examples are melamine-formaldehyde prepolymer and melamine foam material without the addition of organomontmorillonite modification. The specific preparation process is as follows: 1000 g of formaldehyde aqueous solution was stirred at a constant temperature of 80℃~90℃ for 1 h. 130 g of paraformaldehyde was added, and the temperature was raised to 95℃~100℃. 700 g of melamine was added, and the reaction was continued at 95℃~100℃, with the turbidity point monitored to track the reaction progress. When the turbidity point reached 10℃~15℃, 70 g of sodium bisulfite was added. The reaction was continued at 95℃~100℃ until the desired turbidity point was reached. Heating was then stopped, and the temperature was rapidly lowered to below 40℃ to obtain the melamine-formaldehyde prepolymer.

[0041] 300 g of melamine-formaldehyde prepolymer, 4.8 g of sodium dodecylbenzenesulfonate, 1.2 g of lauryl alcohol polyoxyethylene ether, 30 g of n-pentane, 15 g of cyclopentane, 15 g of acetic acid, and 5 g of water were first mixed at low speed and then at high speed until homogeneous, resulting in a homogeneous foaming emulsion. The foaming emulsion was then foamed for 5 min under microwave treatment at an internal temperature of 95°C to obtain a semi-finished melamine foam material. Finally, the semi-finished product was annealed in hot air at 240°C for 30 min to obtain the finished melamine foam material.

[0042] The performance of the organomontmorillonite-modified melamine foam material obtained in this invention was compared with that of the melamine foam materials disclosed in the prior art (melamine foam materials disclosed in patents CN103665755A, CN104927301A, and CN104231543A), and the results are shown in the table.

[0043] Table 1

[0044] As can be seen from the table above, most of the parameters of the first three embodiments are better than those of the comparative embodiments, especially in terms of tensile strength, flame retardancy and dimensional stability.

[0045] Based on the above experimental results, it is evident that selecting a specific organo-montmorillonite leads to superior mechanical and thermal stability of the prepared organo-montmorillonite-modified melamine foam. Selecting a specific surfactant compound helps improve the uniformity and mechanical properties of the prepared organo-montmorillonite-modified melamine foam. Selecting a specific blowing agent helps control the stability during the foaming stage, improving the mechanical properties of the prepared organo-montmorillonite-modified melamine foam. Selecting a specific catalyst helps control the reaction, improving the mechanical properties of the prepared organo-montmorillonite-modified melamine foam, while also enhancing its uniformity. Selecting a specific raw material ratio yields a specific organo-montmorillonite-modified melamine-formaldehyde prepolymer, which helps improve the mechanical properties of the prepared organo-montmorillonite-modified melamine foam, while also enhancing its flame retardant properties and thermal stability.

[0046] It should be noted that the specific embodiments described above are exemplary, and those skilled in the art can devise various solutions inspired by the disclosure of this invention. These solutions all fall within the scope of this invention and its protection. Those skilled in the art should understand that this specification is illustrative and not intended to limit the scope of the claims. The scope of protection of this invention is defined by the claims and their equivalents.

Claims

1. A flexible melamine foam material modified with organomontmorillonite, characterized in that, Raw materials comprising the following parts by weight: The mixture consists of 100 parts of organomontmorillonite-modified melamine-formaldehyde prepolymer, 0.5-10 parts of surfactant, 2-20 parts of foaming agent, 2-15 parts of catalyst, 0-5 parts of additives, and 0-30 parts of water.

2. The organomontmorillonite-modified flexible melamine foam material according to claim 1, characterized in that, The preparation method of the organomontmorillonite-modified melamine-formaldehyde prepolymer includes the following steps: adding organomontmorillonite to an aqueous formaldehyde solution, stirring at 80℃~90℃ for 1 h, adding paraformaldehyde, raising the temperature to 95℃~100℃, adding melamine, reacting at a constant temperature of 95℃~100℃, monitoring the reaction progress with the turbidity point, and when the turbidity point reaches 10~25℃, adding sodium bisulfite or aminosulfonic acid, continuing the reaction at 95℃~100℃, stopping heating when the desired turbidity point is reached, and rapidly cooling to below 40℃ to obtain the organomontmorillonite-modified melamine-formaldehyde resin prepolymer.

3. The organomontmorillonite-modified flexible melamine foam material according to claim 2, characterized in that, The organomontmorillonite is one or more of the following: di(hydroxyethyl)methyldodecylammonium chloride modified montmorillonite, trimethyldodecylammonium chloride modified montmorillonite, trimethylhexadecylammonium chloride modified montmorillonite, trimethyloctadecylammonium chloride modified montmorillonite, dimethylbenzyloctadecylammonium chloride modified montmorillonite, dimethyldioctadecylammonium chloride modified montmorillonite, and trihydroxyoctadecylammonium chloride modified montmorillonite.

4. The organomontmorillonite-modified flexible melamine foam material according to claim 1, characterized in that, The surfactant is a group of anionic-cationic surfactant complexes, anionic-amphoteric surfactant complexes, and anionic-cationic surfactant complexes.

5. The organomontmorillonite-modified flexible melamine foam material according to claim 1, characterized in that, The foaming agent is one or more of the following: n-pentane, cyclopentane, n-hexane, cyclohexane, petroleum ether, 1,2-dichlorotetrafluoroethane, and 1,2,2-trichloro-1,1-difluoroethane.

6. The organomontmorillonite-modified flexible melamine foam material according to claim 1, characterized in that, The catalyst is one or more of organic or inorganic acids.

7. A method for preparing an organomontmorillonite-modified flexible melamine foam material, characterized in that, Includes the following steps: S1. Organic montmorillonite was added to a formaldehyde aqueous solution and stirred at 80℃~90℃ for 1 h. Paraformaldehyde was added, and the temperature was raised to 95℃~100℃. Melamine was added, and the reaction was carried out at a constant temperature of 95℃~100℃. The reaction progress was monitored by cloud point. When the cloud point reached 10~25℃, sodium bisulfite or aminosulfonic acid was added, and the reaction was continued at 95℃~100℃. When the desired cloud point was reached, the heating was stopped and the temperature was quickly lowered to below 40℃ to obtain the montmorillonite-modified melamine-formaldehyde resin prepolymer. S2 is prepared by uniformly mixing organomontmorillonite-modified melamine-formaldehyde prepolymer with surfactant, foaming agent, catalyst and water to form a homogeneous foaming emulsion, and adding auxiliary agents as needed; S3 The foaming emulsion obtained from S2 is foamed for 5 min to 10 min under microwave action at an internal temperature of 50℃~150℃ to obtain a semi-finished melamine foam material. S4 The semi-finished melamine foam material obtained from S3 is subjected to high-temperature annealing with hot air at 150℃~300℃ for 30 min~60 min to obtain organomontmorillonite modified melamine foam material.

8. The method for preparing the organomontmorillonite-modified flexible melamine foam material according to claim 7, characterized in that, The amount of organomontmorillonite added is 1%-10% of the mass of melamine.

9. The method for preparing the organomontmorillonite-modified flexible melamine foam material according to claim 7, characterized in that, The molar ratio of melamine to formaldehyde is 1:1 to 1:

6.

10. The use of the organomontmorillonite-modified flexible melamine foam material prepared by any of the methods described in claims 1 to 6 or as described in claims 7 to 9 in the preparation of heat insulation, thermal insulation or noise reduction materials.

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