A flame-retardant non-isocyanate polyurethane foam and a preparation method and application thereof

Abstract

This invention discloses a flame-retardant non-isocyanate polyurethane (NIPU) foam, its preparation method, and its applications, belonging to the field of polymer foam material technology. This invention uses melamine phosphate as a reactive monomer, with its primary amine groups participating in the construction of the polymer network. Phosphorus-nitrogen flame-retardant units are introduced into the polyurethane backbone through covalent bonds, solving the migration problem of traditional additive flame retardants. This invention utilizes the cascade exothermic effect of the ammonolysis reaction and the epoxy ring-opening reaction to trigger the hydrolysis of cyclic carbonates to generate carbon dioxide gas, achieving a room-temperature self-foaming process without external heating, thus reducing energy consumption. The resulting NIPU foam exhibits excellent flame-retardant properties (limiting oxygen index >27%, vertical burning rating reaching V-0), high char residue, low heat release, and low smoke release characteristics, providing a new technical approach for the preparation of green, safe, and high-performance polyurethane foam materials.

Description

Technical Field

[0001] This invention belongs to the field of polymer foam material technology, and particularly relates to a flame-retardant non-isocyanate polyurethane foam, its preparation method and application. Background Technology

[0002] Polyurethane foams (PUFs) have been widely used in building insulation, transportation, furniture, and other fields due to their excellent thermal insulation, cushioning, and mechanical properties. However, the synthesis of traditional polyurethanes is highly dependent on isocyanate monomers (such as TDI and MDI), which have high toxicity and carcinogenic risks. The production process also involves highly toxic phosgene, posing a serious threat to the health of production workers and the environment. To address this challenge, non-isocyanate polyurethanes (NIPUs) have emerged. NIPUs are typically prepared through the ring-opening polymerization of cyclic carbonates and polyamines, avoiding the use of isocyanates at the source, making them a cutting-edge and hot topic in the field of polymer materials.

[0003] In the preparation technology of NIPU foam, water-triggered self-foaming technology shows great potential. This technology utilizes an alkaline catalyst to catalyze the in-situ hydrolysis reaction of cyclic carbonates with water, generating carbon dioxide as a foaming agent, making the process safer and more environmentally friendly. However, existing water-triggered foaming systems generally suffer from high reaction temperatures (typically > 100℃), which not only increases production energy consumption but also limits their practical application in many scenarios.

[0004] Furthermore, the flammability of polyurethane foam, as an organic polymer material, is a core bottleneck limiting its safe application. Traditional solutions involve adding flame retardants, such as halogenated compounds and phosphate esters. However, these additive flame retardants, when physically blended with the polymer matrix, are prone to migration and exudation, leading to a decline in the material's flame retardant performance over time and potentially adversely affecting its mechanical properties. Reactive flame retardants, linked to the polymer backbone through chemical bonds, can achieve long-lasting and highly efficient flame retardant effects. Melamine phosphate (MP) is a highly efficient phosphorus-nitrogen synergistic halogen-free flame retardant, but current research primarily uses it as an additive, failing to effectively utilize its primary amine group reactivity, thus limiting its flame retardant efficiency and compatibility with the matrix. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention proposes a flame-retardant non-isocyanate polyurethane foam, its preparation method, and its application.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] This invention provides a flame-retardant non-isocyanate polyurethane foam, comprising the following raw materials: multifunctional epoxide, multifunctional cyclic carbonate, polyamine compound, melamine phosphate flame retardant, foaming agent and inorganic filler;

[0008] The multifunctional epoxide is selected from the following compounds: trimethylolpropane triglycidyl ether (... ), Glyceryl triglycidyl ether ( ), diglycidyl ether ( ), 1,3-butadiene diepoxide ( ), Bisphenol A diglycidyl ether ( ), 1,4-bis(ethylene oxide-2-yl)benzene ( ), triglycidol ( ), 1,4-Butanediol diglycidyl ether ( ), triglycidyl isocyanurate ( ), phloroglucinol triglycidyl ether ( Multifunctional aliphatic epoxy resins ( Pentaerythritol tetraglycidyl ether ( ) or tetrafunctional amine ester epoxy resin ( );

[0009] The multifunctional cyclic carbonates are selected from the following compounds: , , , , , , , , , , , , or ;

[0010] The polyamine compound is selected from m-phenylenediamine (… ), 1,3-cyclohexanedimethylamine ( ), Tri(2-aminoethyl)amine ), hexamethylenediamine ( ), triethylene glycol diamine ( ), triethylenetetramine ( N,N,N',N'-Tetra(2-aminoethyl)ethylenediamine ), 1,3,5-triaminobenzene ( ), 1,2,4,5-phenyltetramine ( ), 1,3,5-cyclohexanetriamine ( ), 4,4'-diaminodiphenylmethane ( ), 3,3'-dimethyl-4,4'-diaminodiphenylmethane ( N,N,N',N'-tetra(2-aminoethyl)-p-phenylenediamine ), tri(4-aminophenyl)amine ), diethylenetriamine ( ) or ethylenediamine ( ).

[0011] The principle of this invention is as follows: melamine phosphate directly participates in the polymerization reaction through its primary amine group and is covalently introduced into the polyurethane network, thereby forming a stable phosphorus-nitrogen flame-retardant skeleton. Through this design, melamine phosphate, as a reactive flame-retardant monomer, is fixed in the foam skeleton, effectively avoiding the problem of flame retardant migration. Simultaneously, cascade exothermic reactions enable low-temperature triggering of in-situ carbon dioxide generation, achieving foaming and significantly reducing energy consumption in preparation. Furthermore, no external solvent is required during the foaming process, making the operation simpler and more environmentally friendly, eliminating the need for additional solvent removal. The resulting flame-retardant non-isocyanate polyurethane foam exhibits excellent flame-retardant properties, high char residue, low heat release, and low smoke release characteristics, providing a new technical approach for the preparation of green, safe, and high-performance polyurethane foam materials. Based on the reactive characteristics of the primary amine group of melamine phosphate, this invention introduces it as a flame-retardant monomer into the polymerization system to prepare a flame-retardant non-isocyanate polyurethane foam with a limiting oxygen index (LOI) ≥27% and vertical burning performance reaching UL-94 V-0 level.

[0012] Furthermore, the molar ratio of the sum of the cyclic carbonate groups in the polyfunctional cyclic carbonate and the epoxy groups in the polyfunctional epoxide to the sum of the amino groups in the polyamine compound and the melamine phosphate flame retardant is 1:(0.2-3).

[0013] Furthermore, the preparation method of the polyfunctional cyclic carbonate is as follows: polyfunctional epoxide reacts with carbon dioxide under a catalyst and a pressure of 3.0-5.0 MPa and a temperature of 70-90°C to generate the polyfunctional cyclic carbonate.

[0014] Furthermore, in the method for preparing the multifunctional cyclic carbonate, the catalyst is selected from one of quaternary ammonium salts, quaternary phosphine salts, and metal complex catalysts; the amount of catalyst added is 1-10% of the mass of the multifunctional epoxide.

[0015] For example, in the method for preparing the multifunctional cyclic carbonate, the quaternary ammonium salt is selected from tetrabutylammonium iodide (TBAI) or tetrabutylammonium bromide (TBAB); the quaternary phosphine salt is selected from tetrabutylphosphine bromide, tetrabutylphosphine chloride, methyltriphenylphosphine bromide or butyltriphenylphosphine bromide; and the metal complex catalyst is selected from tetraphenylporphyrin aluminum or Schiff base aluminum.

[0016] Furthermore, the phosphorus content in the flame-retardant non-isocyanate polyurethane foam is 0.5-3.0 wt%.

[0017] Furthermore, the amount of inorganic filler added is 6-48% of the mass of the multifunctional cyclic carbonate.

[0018] Furthermore, the inorganic filler is selected from hydrotalcite or surface-modified hydrotalcite.

[0019] Furthermore, the foaming agent is a mixture of water and an alkaline compound.

[0020] Furthermore, the molar ratio of the alkaline compound in the foaming agent to the cyclic carbonate groups in the polyfunctional cyclic carbonate is (0.025-0.125):1, and the molar ratio of water in the foaming agent to the cyclic carbonate groups in the polyfunctional cyclic carbonate is (0.05-0.25):1.

[0021] The present invention also provides a method for preparing the above-mentioned flame-retardant non-isocyanate polyurethane foam, comprising the following steps: mixing a multifunctional cyclic carbonate, a polyamine compound, a multifunctional epoxide, a melamine phosphate flame retardant and an inorganic filler, then adding a foaming agent, and reacting and self-foaming the resulting mixture at room temperature to obtain the flame-retardant non-isocyanate polyurethane foam.

[0022] The present invention also provides the application of the above-mentioned flame-retardant non-isocyanate polyurethane foam in flame-retardant materials.

[0023] Compared with the prior art, the present invention has the following advantages and technical effects:

[0024] This invention provides a green, environmentally friendly, structurally sound, and technologically simple reactive flame-retardant self-foaming non-isocyanate polyurethane foam—flame-retardant non-isocyanate polyurethane foam. This system introduces melamine phosphate as a reactive monomer into the polymerization network. The reaction of melamine phosphate with cyclic carbonates and their epoxy groups allows phosphorus-nitrogen flame-retardant units to be covalently bonded to the foam skeleton, solving the problems of easy migration and flame-retardant performance degradation associated with traditional additive flame retardants. This invention utilizes the cascade exothermic effect of ammonolysis, epoxy ring-opening reaction, and alkali-catalyzed hydrolysis to achieve self-foaming at room temperature, avoiding high-temperature heating processes and significantly reducing energy consumption. The resulting foam maintains low density while exhibiting excellent flame-retardant properties (limiting oxygen index ≥27%, vertical burning rating reaching UL-94 V-0). This technology provides a new solution for preparing green, safe, energy-saving, and high-performance NIPU foam materials. Attached Figure Description

[0025] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0026] Figure 1 The 1H NMR spectrum of trimethylolpropane triglycidyl ether and the trihydroxypropane tricyclic carbonate obtained in Example 1 ( 1 H NMR spectrum;

[0027] Figure 2 The image shows a cross-sectional view (left) and a scanning electron microscope image (right) of the flame-retardant non-isocyanate polyurethane foam obtained in Example 9. Detailed Implementation

[0028] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0029] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Every smaller range between any stated value or intermediate value within a stated range, and any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0030] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0031] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be readily apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0032] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0033] Embodiments of the present invention provide a flame-retardant non-isocyanate polyurethane foam comprising the following raw materials: polyfunctional epoxide, polyfunctional cyclic carbonate, polyamine compound, melamine phosphate flame retardant, foaming agent and inorganic filler;

[0034] Multifunctional epoxides are selected from the following compounds: , , , , , , , , , , , or The aforementioned epoxy compounds can rapidly couple with carbon dioxide to form corresponding cyclic carbonate compounds;

[0035] Multifunctional cyclic carbonates are selected from the following compounds: , , , , , , , , , , , , or The aforementioned multifunctional cyclic carbonates can react rapidly with amino compounds and can be rapidly hydrolyzed to generate carbon dioxide gas, ensuring the foaming speed.

[0036] Polyamine compounds are selected from the following compounds: , , , , , , , , , , , , , , or .

[0037] The flame-retardant non-isocyanate polyurethane (NIPU) foam provided by this invention has the structure shown in Formula 1. This invention uses melamine phosphate as the reactive monomer, with its primary amine groups participating in the construction of the polymer network. Phosphorus-nitrogen flame-retardant units are introduced into the polyurethane backbone through covalent bonds, solving the migration problem of traditional additive flame retardants. This invention utilizes the cascade exothermic effect of the ammonolysis reaction and the epoxy ring-opening reaction to trigger the hydrolysis of cyclic carbonates to generate carbon dioxide gas, achieving a room-temperature self-foaming process without external heating, significantly reducing energy consumption. The resulting NIPU foam exhibits excellent flame-retardant properties (limiting oxygen index > 27%, vertical burning rating reaching V-0), high char residue, low heat release, and low smoke release characteristics, providing a new technical approach for the preparation of green, safe, and high-performance polyurethane foam materials.

[0038]

[0039] Formula 1

[0040] In Equation 1, R is selected from:

[0041] , , , , , , , , , , , , , , or ;

[0042] R 1 With R 2 Independently selected from at least one of the following structures:

[0043] , , , , , , , , , , , or .

[0044] In an embodiment of the present invention, the molar ratio of the sum of the cyclic carbonate groups in the polyfunctional cyclic carbonate and the epoxy groups in the polyfunctional epoxide to the sum of the amino groups in the polyamine compound and the melamine phosphate flame retardant is 1:(0.2-3).

[0045] In an embodiment of the present invention, the preparation method of the polyfunctional cyclic carbonate is as follows: a polyfunctional epoxide reacts with carbon dioxide under a catalyst and a pressure of 3.0-5.0 MPa and a temperature of 70-90°C to generate a polyfunctional cyclic carbonate.

[0046] In an embodiment of the present invention, in the preparation method of the multifunctional cyclic carbonate, the catalyst is selected from one of quaternary ammonium salt, quaternary phosphine salt and metal complex catalyst; the amount of catalyst added is 1-10% of the mass of the multifunctional epoxide.

[0047] For example, in the preparation method of multifunctional cyclic carbonates, the quaternary ammonium salt is selected from tetrabutylammonium iodide (TBAI) or tetrabutylammonium bromide (TBAB); the quaternary phosphine salt is selected from tetrabutylphosphine bromide, tetrabutylphosphine chloride, methyltriphenylphosphine bromide, or butyltriphenylphosphine bromide; and the metal complex catalyst is selected from tetraphenylporphyrin aluminum or Schiff base aluminum. In the embodiments of the present invention, the phosphorus content in the flame-retardant non-isocyanate polyurethane foam is 0.5-3.0 wt%, that is, the amount of melamine phosphate flame retardant used is such that the phosphorus content in the final flame-retardant non-isocyanate polyurethane foam is 0.5-3.0 wt%.

[0048] In embodiments of the present invention, the amount of inorganic filler added is 6-48% of the mass of the multifunctional cyclic carbonate.

[0049] In embodiments of the present invention, the inorganic filler is selected from hydrotalcite or surface-modified hydrotalcite.

[0050] This invention uses silane coupling agents or titanate coupling agents to modify hydrotalcite, enhancing its compatibility with the foam matrix. Exemplarily, the specific method for surface modification of hydrotalcite is as follows: hydrotalcite powder is dried at 100°C to activate its surface. Simultaneously, 2% (by weight of hydrotalcite) of silane coupling agent or titanate coupling agent is weighed and dissolved in a 95:5 volume ratio of ethanol-water mixture or anhydrous ethanol, and a hydrolysis reaction is carried out under stirring. Subsequently, the activated hydrotalcite is slowly added to the above solution, the temperature is raised to 70°C and maintained for 3 hours. After the reaction, the product is filtered, washed with anhydrous ethanol to remove impurities, and then vacuum dried at 80°C to obtain surface-modified hydrotalcite.

[0051] For example, the silane coupling agent is selected from (3-aminopropyl)triethoxysilane; the titanate coupling agent is selected from isopropyltriisostearoyl titanate or isopropyltris(octylpyrophosphate)titanate.

[0052] In embodiments of the present invention, the foaming agent is a mixture of water and an alkaline compound.

[0053] In embodiments of the present invention, the molar ratio of the alkaline compound in the foaming agent to the cyclic carbonate groups in the polyfunctional cyclic carbonate is (0.025-0.125):1, and the molar ratio of water in the foaming agent to the cyclic carbonate groups in the polyfunctional cyclic carbonate is (0.05-0.25):1.

[0054] The embodiments of the present invention also provide a method for preparing the above-mentioned flame-retardant non-isocyanate polyurethane foam, comprising the following steps: mixing a multifunctional cyclic carbonate, a polyamine compound, a multifunctional epoxide, a melamine phosphate flame retardant and an inorganic filler, then adding a foaming agent, and reacting and self-foaming the resulting mixture at room temperature to obtain the flame-retardant non-isocyanate polyurethane foam.

[0055] Embodiments of the present invention also provide the application of the above-described flame-retardant non-isocyanate polyurethane foam in flame-retardant materials.

[0056] Unless otherwise specified, the room temperature in this invention is 25±2℃.

[0057] All raw materials used in the embodiments of the present invention were obtained through commercial purchase.

[0058] The technical solution of the present invention will be further illustrated by the following embodiments.

[0059] Example 1

[0060] The synthetic route for trihydroxypropane tricyclic carbonate (TMPTC) is as follows:

[0061]

[0062] The specific steps are as follows: 20 g of trimethylolpropane triglycidyl ether (TMPTE) and 0.61 g of tetrabutylammonium iodide (TBAI) were added to a 50 mL high-pressure reactor; after sealing the reactor, 5.0 MPa carbon dioxide (CO2) was introduced, and the mixture was stirred in an oil bath at 80℃ for 24 h. The pressure inside the reactor was then released (pressure relief), and the viscous product was recovered under reduced pressure. The product was then vacuum dried at 60℃ for 16 h to obtain 26.7 g of trihydroxypropane tricyclic carbonate, with a yield of 93.0%; the product was analyzed by 1H NMR spectroscopy (NMR spectroscopy). Figure 1 Analysis confirmed that the cyclization conversion rate of its epoxy groups was greater than 98%.

[0063] Example 2

[0064] The synthesis of bisphenol A diglycidyl ether cyclic carbonate was carried out as follows: 37.0 g of bisphenol A diglycidyl ether (DGEBA) and 0.74 g of tetrabutylammonium bromide (TBAB) were added to a 100 mL high-pressure reactor; after sealing the reactor, 3.0 MPa CO2 was introduced, and the mixture was stirred in an oil bath at 90 °C for 16 h. The pressure was then released, and the viscous product was recovered under reduced pressure. The product was then vacuum dried at 60 °C for 12 h to obtain 45.3 g of bisphenol A diglycidyl ether cyclic carbonate, with a yield of 98.8%. 1 1H NMR analysis confirmed that the cyclization conversion rate of its epoxy groups was greater than 98%.

[0065] Example 3

[0066] The synthesis of triglycidyl isocyanate cyclic carbonate (TCCIC) was carried out as follows: 29.7 g of triglycidyl isocyanate (TGIC, 0.1 mol) and 0.60 g of TBAB were added to a 100 mL high-pressure reactor; after sealing the reactor, 5.0 MPa CO2 was introduced, and the reaction was stirred in an oil bath at 80 °C for 12 h. After the reaction was completed, the pressure was released, and the product was dissolved in ethyl acetate. The catalyst was removed by filtration, and the filtrate was concentrated under reduced pressure and dried in a vacuum oven at 60 °C for 8 h to constant weight, finally yielding 42.2 g of a white solid product—triglycidyl isocyanate cyclic carbonate, with a yield of 98.3%. 1 1H NMR analysis confirmed that the cyclization conversion rate of its epoxy groups was greater than 97%.

[0067] Example 4

[0068] The synthesis of pentaerythritol tetraglycidyl ether cyclic carbonate (PETCC) was carried out as follows: 36.0 g of pentaerythritol tetraglycidyl ether (PETGE) and 0.72 g of methyltriphenylphosphine bromide were added to a 100 mL high-pressure reactor; after sealing the reactor, 4.0 MPa CO2 was introduced, and the reaction was stirred in an oil bath at 70 °C for 24 h. After the reaction was completed, the pressure was released, the viscous product was recovered under reduced pressure, and dried in a vacuum oven at 60 °C for 16 h to constant weight, finally yielding 52.8 g of a colorless, transparent viscous liquid—pentaerythritol tetraglycidyl ether cyclic carbonate—with a yield of 98.5%. 1 1H NMR analysis confirmed that the cyclization conversion rate of its epoxy groups was greater than 98%.

[0069] Example 5

[0070] The synthesis of phloroglucinol triglycidyl ether cyclic carbonate was carried out as follows: 29.4 g of phloroglucinol triglycidyl ester (0.1 mol), 0.34 g of tetrabutylphosphine bromide, and 0.067 g of tetraphenylporphyrin aluminum chloride were added to a 100 mL high-pressure reactor. After sealing the reactor, 5.0 MPa CO2 was introduced, and the reaction was stirred in an oil bath at 90 °C for 12 h. After the reaction was completed, the pressure was released, and the product was dissolved in ethyl acetate. The catalyst was removed by filtration, and the filtrate was concentrated under reduced pressure and dried in a vacuum oven at 60 °C for 8 h to constant weight, finally yielding 42.0 g of a white solid product—phloroglucinol triglycidyl ether cyclic carbonate, with a yield of 98.5%. 1 1H NMR analysis confirmed that the cyclization conversion rate of its epoxy groups was greater than 97%.

[0071] Example 6

[0072] The synthesis of melamine phosphate was carried out as follows: 37.84 g (0.3 mol) of melamine was added to 750 mL of deionized water in a three-necked round-bottom flask equipped with a stirrer to obtain a mixture. The mixture was heated and stirred in an oil bath at 95°C for 30 minutes to ensure that the melamine was completely dissolved to form a clear solution. Subsequently, 34.6 g of 85 wt% phosphoric acid aqueous solution was added dropwise through a constant-pressure dropping funnel. After the addition was complete, the reaction system was stirred at 95°C for 1 hour, during which a large amount of white precipitate was observed to form. After the reaction was completed, the mixture was naturally cooled to room temperature and filtered. The obtained filter cake was washed three times with deionized water and dried to constant weight in a vacuum oven at 80°C, finally yielding a white powdery solid—melamine phosphate (MP)—with a yield of 95%.

[0073] Example 7

[0074] The synthesis of melamine phosphite was carried out as follows: 37.84 g (0.3 mol) of melamine was added to 750 mL of deionized water in a three-necked round-bottom flask equipped with a stirrer to obtain a mixture. The mixture was heated and stirred in an oil bath at 95°C for 30 minutes to ensure that the melamine was completely dissolved to form a clear solution (i.e., a melamine hot solution). Subsequently, 49.2 g of a 50 wt% aqueous solution of phosphorous acid was added dropwise to the above melamine hot solution through a constant-pressure dropping funnel. After the addition was complete, the reaction system was kept at 95°C and stirred for 1 hour. During this period, a large amount of white solid was observed to precipitate. After the reaction was completed, the mixture was naturally cooled to room temperature and then filtered. The obtained filter cake was washed several times with an appropriate amount of deionized water to remove residual impurities and dried to constant weight in a vacuum oven at 80°C, finally yielding a white powdery solid—melamine phosphite (MPi)—with a yield of 93%.

[0075] Example 8

[0076] The synthesis of melamine hypophosphite was carried out using the following steps: 37.84 g (0.3 mol) of melamine was dispersed in 750 mL of deionized water in a three-necked round-bottom flask equipped with a stirrer to obtain a mixture. The mixture was heated and stirred in an oil bath at 95°C for 30 minutes to ensure complete dissolution of the melamine and the formation of a clear hot solution. Subsequently, 39.6 g of a 50 wt% aqueous hypophosphite solution was added dropwise to the hot solution through a constant-pressure dropping funnel. After the addition was complete, the reaction system was kept at 95°C and stirred for 1 hour. During this process, a large amount of white precipitate was observed to gradually form. After the reaction was completed, the mixture was naturally cooled to room temperature and then filtered. The resulting filter cake was washed with sufficient deionized water to thoroughly remove unreacted raw materials and impurities. Finally, it was dried in a vacuum oven at 80°C to constant weight to obtain the final product—white powdered melamine hypophosphite (MHP) with a yield of 95%.

[0077] Comparative Example 1

[0078] A method for preparing a flame-retardant non-isocyanate polyurethane foam includes the following steps: 21.7 g (0.05 mol) of trihydroxypropane tricyclic carbonate (synthesized in Example 1), 15.1 g (0.05 mol) of trimethylolpropane triglycidyl ether, and 5.2 g of hydrotalcite are added to a cylindrical plastic vial with a diameter of 5 cm. The mixture is homogenized at 5500 rpm for 5 min until uniformly mixed. 17.9 g (0.13 mol) of m-phenylenediamine (XDA) is added and manually stirred until homogeneous. Then, an aqueous solution prepared from 0.63 g (0.01 mol) of KOH and 0.41 g of deionized water is added. After brief mixing, the mixture is allowed to self-foam at room temperature for 45 s, yielding a density of 152.1 mg / cm³. 3 The non-isocyanate polyurethane foam has a limiting oxygen index (LOI) of 21.3, and its vertical burning performance is lower than UL-94 V-2. Its char residue is 21.8%, and its total heat release is 131.55 MJ / m³. 2 The total smoke emission was 1682.71 m³. 2 .

[0079] Example 9

[0080] A method for preparing flame-retardant non-isocyanate polyurethane foam includes the following steps: 21.7 g (0.05 mol) of trihydroxypropane tricyclic carbonate (synthesized in Example 1), 15.1 g (0.05 mol) of trimethylolpropane triglycidyl ether, 5.2 g of hydrotalcite, and 11.2 g (0.05 mol) of melamine phosphate (synthesized in Example 5) are added to a cylindrical plastic vial with a diameter of 5 cm. The mixture is homogenized at 5500 rpm for 5 min until homogeneous. 12.1 g (0.09 mol) of XDA is added and manually stirred until homogeneous. Then, an aqueous solution prepared from 0.63 g (0.01 mol) of KOH and 0.41 g of deionized water is added. After brief mixing, the mixture is allowed to self-foam at room temperature for 40 s, yielding a density of 194.2 mg / cm³. 3 This flame-retardant non-isocyanate polyurethane foam has an LOI of 27.6 and achieves a UL-94 V-0 vertical burning rating. It contains 2.33 wt% phosphorus, has a residual char rate of 23.8%, and a total heat release of 101.63 MJ / m³. 2 The total smoke emission was 1097.62 m³. 2 .

[0081] The cross-sectional view and scanning electron microscope image of the flame-retardant non-isocyanate polyurethane foam obtained in this embodiment are as follows: Figure 2 As shown, the pores formed by this system are uniformly distributed and have appropriate pore sizes.

[0082] As can be seen from Comparative Example 1 and Example 9, the present invention utilizes the reaction of melamine phosphate with cyclic carbonate and its epoxy groups to covalently bind phosphorus-nitrogen flame retardant units into the foam skeleton, which can effectively improve the flame retardant performance of the foam and exhibit characteristics of high limiting oxygen index, high char residue, low heat release and smoke release.

[0083] Example 10

[0084] A method for preparing a flame-retardant non-isocyanate polyurethane foam includes the following steps: 32.1 g (0.075 mol) of bisphenol A diglycidyl ether cyclic carbonate (synthesized in Example 2), 25.5 g (0.075 mol) of bisphenol A diglycidyl ether, 15.0 g of hydrotalcite, and 11.2 g (0.05 mol) of melamine phosphate (synthesized in Example 5) are added to a cylindrical plastic vial with a diameter of 5 cm. The mixture is homogenized at 5000 rpm for 5 min until homogeneous. 2.72 g (0.02 mol) of XDA and 1.29 g (0.01 mol) of 1,3,5-cyclohexanetriamine are added, and the mixture is manually stirred until homogeneous. Then, an aqueous solution prepared from 0.40 g (0.01 mol) of KOH and 0.80 g of deionized water is added. After brief mixing, the mixture is allowed to foam at room temperature for 42 s, yielding a foam with a density of 216.8 mg / cm³. 3 It is a flame-retardant non-isocyanate polyurethane foam with an LOI of 28.1 and a vertical burning performance of UL-94 V-0, and a phosphorus content of 1.74%.

[0085] Example 11

[0086] A method for preparing flame-retardant non-isocyanate polyurethane foam includes the following steps: 21.5 g (0.05 mol) of tricyclic isocyanurate carbonate (synthesized in Example 3), 14.9 g (0.05 mol) of triglycidyl isocyanurate, 20.4 g of hydrotalcite, and 11.2 g (0.05 mol) of melamine phosphate (synthesized in Example 5) are added to a cylindrical plastic vial with a diameter of 5 cm. The mixture is homogenized at 6000 rpm for 5 min until homogeneous. 12.1 g (0.05 mol) of m-phenylenediamine (XDA) and 28.2 g (0.2 mol) of 1,3-cyclohexanedimethylamine are added, and the mixture is manually stirred until homogeneous. Then, an aqueous solution prepared from 1.12 g (0.02 mol) of KOH and 0.49 g of deionized water is added. After brief mixing, the mixture is allowed to foam at room temperature for 50 s, yielding a density of 189.4 mg / cm³. 3 It is a flame-retardant non-isocyanate polyurethane foam with an LOI of 28.9 and a vertical burning performance of UL-94 V-0, and a phosphorus content of 1.41 wt%.

[0087] Example 12

[0088] A method for preparing a flame-retardant non-isocyanate polyurethane foam includes the following steps: 15.0 g (0.028 mol) pentaerythritol tetracyclic carbonate (synthesized in Example 4), 8.4 g (0.023 mol) pentaerythritol tetraglycidyl ether, 5.2 g hydrotalcite, and 11.2 g (0.05 mol) melamine phosphate (synthesized in Example 5) are added to a cylindrical plastic vial with a diameter of 5 cm. The mixture is homogenized at 5000 rpm for 5 min until homogeneous. 17.85 g (0.09 mol) 4,4'-diaminodiphenylmethane is added and manually stirred until homogeneous. Then, an aqueous solution prepared from 0.80 g (0.01 mol) KOH and 0.60 g deionized water is added. After brief mixing, the mixture is allowed to foam at room temperature for 38 s, yielding a density of 164.5 mg / cm³. 3 It is a flame-retardant non-isocyanate polyurethane foam with an LOI of 31.2 and a vertical burning performance of UL-94 V-0, and a phosphorus content of 2.62 wt%.

[0089] Example 13

[0090] A method for preparing a flame-retardant non-isocyanate polyurethane foam includes the following steps: 21.7 g (0.05 mol) of trihydroxypropane tricyclic carbonate (synthesized in Example 1), 15.1 g (0.05 mol) of trimethylolpropane triglycidyl ether, 30.0 g of hydrotalcite, and 10.3 g (0.05 mol) of melamine phosphite (synthesized in Example 6) are added to a cylindrical plastic vial with a diameter of 5 cm. The mixture is homogenized at 5500 rpm for 5 min until homogeneous. 12.1 g (0.09 mol) of XDA is added and manually stirred until homogeneous. Then, an aqueous solution prepared from 0.63 g (0.01 mol) of KOH and 0.41 g of deionized water is added. After brief mixing, the mixture is allowed to self-foam at room temperature for 62 s, yielding a density of 187.58 mg / cm³. 3 It is a flame-retardant non-isocyanate polyurethane foam with an LOI of 27.1 and vertical burning performance reaching UL-94 V-0 level, and a phosphorus content of 1.70 wt%.

[0091] Example 14

[0092] A method for preparing a flame-retardant non-isocyanate polyurethane foam includes the following steps: 21.7 g (0.05 mol) of trihydroxypropane tricyclic carbonate (synthesized in Example 1), 15.1 g (0.05 mol) of trimethylolpropane triglycidyl ether, 10.8 g of hydrotalcite, and 9.6 g (0.05 mol) of melamine hypophosphite (synthesized in Example 7) are added to a cylindrical plastic vial with a diameter of 5 cm. The mixture is homogenized at 5500 rpm for 5 min until homogeneous. 12.1 g (0.09 mol) of XDA is added and manually stirred until homogeneous. Then, an aqueous solution prepared from 0.63 g (0.01 mol) of KOH and 0.41 g of deionized water is added. After brief mixing, the mixture is allowed to foam at room temperature for 36 s, yielding a density of 202.55 mg / cm³. 3 It is a flame-retardant non-isocyanate polyurethane foam with a limiting oxygen index (LOI) of 29.2 and vertical burning performance reaching UL-94 V-0 level, and a phosphorus content of 2.20 wt%.

[0093] Example 15

[0094] A method for preparing a flame-retardant non-isocyanate polyurethane foam includes the following steps: 21.5 g (0.05 mol) of tricyclic isocyanuric acid carbonate (synthesized in Example 3), 14.7 g (0.05 mol) of phloroglucinol triglycidyl ether, 15.5 g of hydrotalcite, and 11.2 g (0.05 mol) of melamine phosphate (synthesized in Example 5) are added to a cylindrical plastic vial with a diameter of 5 cm. The mixture is homogenized at 6000 rpm for 5 min until homogeneous. Then, 14.5 g (0.05 mol) of tris(4-aminophenyl)amine and 2.07 g (0.02 mol) of diethylenetriamine are added, and the mixture is manually stirred until homogeneous. Finally, an aqueous solution prepared from 1.12 g (0.02 mol) of KOH and 0.49 g of deionized water is added. After brief mixing, the mixture is allowed to foam at room temperature for 52 s, yielding a density of 208.56 mg / cm³. 3 It is a flame-retardant non-isocyanate polyurethane foam with a limiting oxygen index (LOI) of 31.2 and vertical burning performance reaching UL-94 V-0 level, and a phosphorus content of 1.91 wt%.

[0095] Example 16

[0096] A method for preparing a flame-retardant non-isocyanate polyurethane foam includes the following steps: 15.9 g (0.05 mol) triglycidylamine cyclic carbonate, 29.4 g (0.05 mol) multifunctional arachidonic epoxy resin, 15.0 g hydrotalcite, and 10.4 g (0.05 mol) melamine phosphite (synthesized in Example 6) are added to a cylindrical plastic vial with a diameter of 5 cm. The mixture is homogenized and stirred at 8000 rpm for 5 min until homogeneous. 24.6 g (0.2 mol) 1,3,5-triaminobenzene is added and manually stirred until homogeneous. Then, an aqueous solution prepared from 0.28 g (0.005 mol) KOH and 0.60 g deionized water is added. After brief mixing, the mixture is allowed to foam at room temperature for 50 s, yielding a density of 201.42 mg / cm³. 3 It is a flame-retardant non-isocyanate polyurethane foam with an LOI of 30.8 and a vertical burning performance of UL-94 V-0, and a phosphorus content of 1.61 wt%.

[0097] Example 17

[0098] A method for preparing flame-retardant non-isocyanate polyurethane foam includes the following steps: 86.8 g (0.08 mol) of cyclic carbonate prepared from tetrafunctional amine ester epoxy resin, 3.2 g (0.02 mol) of 1,4-bis(ethylene oxide-2-yl)benzene, 40.8 g of hydrotalcite, and 11.2 g (0.05 mol) of melamine phosphate are added to a cylindrical plastic bottle with a diameter of 5 cm. The mixture is homogenized at 4000 rpm for 5 min until uniform. 34.9 g (0.2 mol) of 1,2,4,5-phenyltetramine is added and manually stirred until homogeneous. Then, an aqueous solution prepared from 0.56 g (0.01 mol) of KOH and 0.60 g of deionized water is added. After brief mixing, the mixture is allowed to foam at room temperature for 72 s, yielding a density of 210.82 mg / cm³. 3 It is a flame-retardant non-isocyanate polyurethane foam with an LOI of 28.7 and a vertical burning performance of UL-94 V-0, and a phosphorus content of 0.87 wt%.

[0099] Example 18

[0100] A method for preparing flame-retardant non-isocyanate polyurethane foam includes the following steps: 20.3 g (0.05 mol) of glycerol triglycidyl ether cyclic carbonate, 13.0 g (0.05 mol) of glycerol triglycidyl ether, 16.0 g of hydrotalcite, and 11.2 g (0.05 mol) of melamine phosphate are added to a cylindrical plastic bottle with a diameter of 5 cm. The mixture is homogenized at 6000 rpm for 5 min until uniform. 11.6 g (0.1 mol) of hexamethylenediamine is added and manually stirred until homogeneous. Then, an aqueous solution prepared from 0.56 g (0.01 mol) of KOH and 0.50 g of deionized water is added. After brief mixing, the mixture is allowed to self-foam at room temperature for 46 s, yielding a foam with a density of 195.5 mg / cm³. 3 It is a flame-retardant non-isocyanate polyurethane foam with an LOI of 30.7 and a vertical burning performance of UL-94 V-0, and a phosphorus content of 1.92 wt%.

[0101] Example 19

[0102] A method for preparing flame-retardant non-isocyanate polyurethane foam includes the following steps: 10.9 g (0.05 mol) diglycidyl ether cyclic carbonate, 9.8 g (0.075 mol) diglycidyl ether, 15.0 g hydrotalcite, and 11.2 g (0.05 mol) melamine phosphate are added to a cylindrical plastic bottle with a diameter of 5 cm. The mixture is homogenized at 5500 rpm for 5 min until homogeneous. 11.7 g (0.08 mol) tris(2-aminoethyl)amine is added and manually stirred until homogeneous. Then, an aqueous solution prepared from 1.12 g (0.02 mol) KOH and 0.48 g deionized water is added. After brief mixing, the mixture is allowed to foam at room temperature for 52 s to obtain a density of mg / cm³. 3 It is a flame-retardant non-isocyanate polyurethane foam with an LOI of 29.6 and vertical burning performance reaching UL-94 V-0 level, and a phosphorus content of 2.05 wt%.

[0103] Example 20

[0104] A method for preparing flame-retardant non-isocyanate polyurethane foam includes the following steps: 8.7 g (0.05 mol) of 1,3-butadiene dicyclic carbonate, 6.5 g (0.075 mol) of 1,3-butadiene diepoxide, 18.0 g of hydrotalcite, and 11.2 g (0.05 mol) of melamine phosphate are added to a cylindrical plastic bottle with a diameter of 5 cm. The mixture is homogenized at 6000 rpm for 5 min until homogeneous. 11.3 g (0.05 mol) of 3,3'-dimethyl-4,4'-diaminodiphenylmethane and 2.9 g (0.02 mol) of triethylenetetramine are added, and the mixture is manually stirred until homogeneous. Then, an aqueous solution prepared from 1.12 g (0.02 mol) of KOH and 0.52 g of deionized water is added. After brief mixing, the mixture is allowed to foam at room temperature for 58 s, yielding a density of 209.4 mg / cm³. 3 It is a flame-retardant non-isocyanate polyurethane foam with an LOI of 30.3 and a vertical burning performance of UL-94 V-0, and a phosphorus content of 1.90 wt%.

[0105] Example 21

[0106] A method for preparing flame-retardant non-isocyanate polyurethane foam includes the following steps: 15.9 g (0.05 mol) triglycidylamine cyclic carbonate, 9.3 g (0.05 mol) triglycidylamine, 15.5 g hydrotalcite, and 11.2 g (0.05 mol) melamine phosphate are added to a cylindrical plastic bottle with a diameter of 5 cm and homogenized at 6000 rpm for 5 min until uniformly mixed; 12.9 g (0.05 mol) N,N,N',N'-tetra(2-aminoethyl)ethylenediamine is added and manually stirred until homogeneous; then an aqueous solution prepared from 1.12 g (0.02 mol) KOH and 0.49 g deionized water is added, and after brief mixing, the mixture is allowed to self-foam at room temperature for 42 s to obtain a density of 192.1 mg / cm³. 3 It is a flame-retardant non-isocyanate polyurethane foam with an LOI of 32.0 and a vertical burning performance of UL-94 V-0, and a phosphorus content of 2.08 wt%.

[0107] Example 22

[0108] A method for preparing flame-retardant non-isocyanate polyurethane foam includes the following steps: 14.5 g (0.05 mol) of 1,4-butanediol diglycidyl ether cyclic carbonate, 15.2 g (0.075 mol) of 1,4-butanediol diglycidyl ether, 15.5 g of hydrotalcite, and 11.2 g (0.05 mol) of melamine phosphate are added to a cylindrical plastic bottle with a diameter of 5 cm. The mixture is homogenized at 5500 rpm for 5 min until uniform. 8.7 g (0.06 mol) of triethylenetetramine is added and manually stirred until homogeneous. Then, an aqueous solution prepared from 1.12 g (0.02 mol) of KOH and 0.50 g of deionized water is added. After brief mixing, the mixture is allowed to self-foam at room temperature for 55 s, yielding a density of 199.8 mg / cm³. 3 It is a flame-retardant non-isocyanate polyurethane foam with an LOI of 29.9 and a vertical burning performance of UL-94 V-0, and a phosphorus content of 1.93 wt%.

[0109] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A flame-retardant non-isocyanate polyurethane foam, characterized in that, The raw materials include: a multifunctional epoxide, a multifunctional cyclic carbonate, a polyamine compound, a melamine phosphate flame retardant, a foaming agent and an inorganic filler; The multifunctional epoxide is selected from trimethylolpropane triglycidyl ether, glycerol triglycidyl ether, diglycidyl ether, 1,3-butadiene diepoxide, bisphenol A diglycidyl ether, 1,4-bis(oxiran-2-yl)benzene, trisglycidyl amine, 1,4-butanediol diglycidyl ether, trisglycidyl isocyanurate, m-trihydroxyphenol triglycidyl ether, a multifunctional araliphatic epoxy resin, pentaerythritol tetraglycidyl ether or a tetrafunctional amine ester epoxy resin; said multifunctional cyclic carbonate is selected from the group consisting of: , , , , , , , , , , , , or ; The polyamine compound is selected from m-xylene diamine, 1,3-cyclohexane diamine, tris(2-aminoethyl)amine, hexamethylene diamine, triethylene glycol diamine, triethylenetetramine, N,N,N',N'-tetra(2-aminoethyl)ethylenediamine, 1,3,5-triaminobenzene, 1,2,4,5-benzene tetramine, 1,3,5-cyclohexane triamine, 4,4'-diaminodiphenyl methane, 3,3'-dimethyl-4,4'-diaminodiphenyl methane, N,N,N',N'-tetra(2-aminoethyl) p-phenylenediamine, tris(4-aminophenyl)amine, diethylenetriamine or ethylenediamine.

2. The flame-retardant non-isocyanate polyurethane foam according to claim 1, characterized in that, The molar ratio of the sum of cyclic carbonate groups in the multifunctional cyclic carbonate and the epoxy groups in the multifunctional epoxide to the sum of the amino groups in the polyamine compound and the melamine phosphate flame retardant is 1:(0.2-3).

3. The flame retarded non-isocyanate polyurethane foam according to claim 2, characterized in that, The preparation method of the multifunctional cyclic carbonate is as follows: the multifunctional epoxide is reacted with carbon dioxide under the action of a catalyst and at a pressure of 3.0-5.0 MPa and a temperature of 70-90℃ to generate the multifunctional cyclic carbonate.

4. The flame-retardant non-isocyanate polyurethane foam according to claim 1, characterized in that, The phosphorus content in the flame-retardant non-isocyanate polyurethane foam is 0.5-3.0 wt%.

5. The flame-retardant non-isocyanate polyurethane foam according to claim 1, wherein, The addition amount of the inorganic filler is 6-48% of the mass of the multifunctional cyclic carbonate.

6. The flame retarded non-isocyanate polyurethane foam according to claim 5, characterized in that, The inorganic filler is selected from hydrotalcite or hydrotalcite modified by surface modification.

7. The flame retarded non-isocyanate polyurethane foam according to claim 1, characterized in that, The foaming agent is a mixture of water and a basic compound.

8. The flame-retardant non-isocyanate polyurethane foam according to claim 7, characterized in that, The molar ratio of the basic compound in the foaming agent to the cyclic carbonate groups in the multifunctional cyclic carbonate is (0.025-0.125):1, and the molar ratio of water in the foaming agent to the cyclic carbonate groups in the multifunctional cyclic carbonate is (0.05-0.25):

1.

9. A process for the preparation of the flame-retardant non-isocyanate polyurethane foam according to any one of claims 1 to 8, characterized in that, The steps include: The multifunctional cyclic carbonate, the polyamine compound, the multifunctional epoxide, the melamine phosphate flame retardant and the inorganic filler are mixed, then the foaming agent is added, and the obtained mixture is reacted at room temperature and self-foamed to obtain the flame-retardant non-isocyanate polyurethane foam.

10. Use of the flame-retardant non-isocyanate polyurethane foam according to any one of claims 1-8 in a flame-retardant material.

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