Ammonium dihydrocarbylphosphinate and preparation method therefor and use thereof

Abstract

Provided are an ammonium dihydrocarbylphosphinate and a preparation method therefor and a use thereof. The ammonium dihydrocarbylphosphinate is obtained by alkylation reaction of an alkyl dihydrocarbylphosphinate and nitrogen on a non-tertiary amine structure in an organic nitrogen-containing compound. The ammonium dihydrocarbylphosphinate has a low melting point, is easy to liquefy, has good compatibility with resin, has a high compatibility speed and is easy to operate, so that the problems that solid amines have high melting points, are difficult to liquefy and are difficult to be compatible with resin systems are solved, and the problems of corrosiveness caused by dialkylphosphinic acid or a residue thereof, and the like are solved. The ammonium dihydrocarbylphosphinate, as a flame retardant, has high flame-retardant efficiency, and can effectively maintain the physical properties of a polymer material, especially the glass transition temperature. The ammonium dihydrocarbylphosphinate involves simple preparation, is free of a solvent and a catalyst, has high atom economy, and is suitable for large-scale production.

Description

A dialkylphosphinate ammonium salt and its preparation method and application Technical Field

[0001] The present invention relates to the field of flame-retardant polymer materials and relates to a dialkylphosphinate ammonium salt and a preparation method and application thereof. Background Art

[0002] Polymer materials are widely used in all walks of life in the national economy. However, since most polymer materials are flammable, in order to reduce the fire disasters caused by them, it is often necessary to meet their flame retardant requirements by using flame retardant modification methods. The simplest way of flame retardant modification is to use flame retardants.

[0003] In recent years, phosphorus-based flame retardants have developed rapidly due to their high flame retardant efficiency and low smoke and toxicity of combustion products, especially dialkylphosphinic acid and its salts.

[0004] CN110945047A discloses the product of diethylphosphinic acid and epoxy reaction and its flame retardant application in polyurethane foam, but it is a monohydroxy functional group flame retardant, reduces the cross-linking degree of polyurethane, and consumes expensive isocyanate.WO2021074684 discloses diethylphosphinic acid or its and epoxy resin product for the flame retardancy of epoxy resin, but diethylphosphinic acid and epoxy reaction reduce the cross-linking functional group of epoxy resin, so that it needs to use trifunctionality and above low exothermic epoxy resin.CN113929967B discloses dialkylphosphinic acid and amine compound neutralization product and its application, such product is solid, has poor compatibility with polymer material, and there is uniform dispersion problem.EP3470444 discloses dialkylphosphinic acid quaternary ammonium salt, for the flame retardancy of polyurethane, but quaternary ammonium salt lacks reactive group, easily precipitates out and runs off.

[0005] In summary, due to their strong acidity, dialkylphosphinic acids can only be used after neutralization. However, this neutralization often reduces the number of functional groups in the neutralizer, which is detrimental to the physical properties of flame-retardant materials. Furthermore, existing solid dialkylphosphinic acid ammonium salts suffer from poor compatibility with polymer materials and a lack of reactivity in dialkylphosphinic acid quaternary ammonium salts.

[0006] Summary of the Invention

[0007] The following is a summary of the subject matter described in detail herein. This summary is not intended to limit the scope of the claims.

[0008] In view of the shortcomings of the prior art, the purpose of this application is to provide a dialkylphosphinate ammonium salt and its preparation method and application.

[0009] To achieve this goal, this application adopts the following technical solutions:

[0010] On the one hand, the present application provides a dialkylphosphinate ammonium salt, which is obtained by an alkylation reaction between a dialkylphosphinate alkyl ester having the structural formula represented by formula (I) and NH3 or a nitrogen on at least one non-tertiary amine structure in an organic nitrogen-containing compound, wherein the alkyl group participating in the alkylation reaction comes from R1 in the structural formula represented by formula (I), the organic nitrogen-containing compound is selected from a primary amine, a secondary amine or an imine compound, and at least one nitrogen atom among the nitrogen atoms that undergoes the alkylation reaction in the dialkylphosphinate ammonium salt has both an H atom and an R1 group obtained from the alkylation reaction.

[0011] R1 is selected from C1~C 18 Straight chain alkyl, C1~C 18 Branched alkyl, or C3~C 18 Cycloalkyl;

[0012] R2 and R3 are independently selected from C1 to C 18 Straight chain alkyl, C1~C 18 Branched alkyl, C3~C 18 Cycloalkyl or C6~C 24 of aromatic groups.

[0013] In one embodiment, R1 is selected from any one of methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl or decyl.

[0014] In one embodiment, R1 is selected from any one of methyl, ethyl, propyl or butyl.

[0015] In one embodiment, R1 is selected from any one of methyl and ethyl.

[0016] In one embodiment, R2 and R3 are independently selected from any one of methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl or phenyl.

[0017] In one embodiment, R2 and R3 are independently selected from any one of ethyl, propyl or butyl.

[0018] In one embodiment, R2 and R3 are ethyl.

[0019] The alkyl dihydrocarbyl phosphinate having the structural formula represented by formula (I) may be a pure alkyl dihydrocarbyl phosphinate or a mixed alkyl dihydrocarbyl phosphinate having different R1, R2, and R3 substituents. For example, the alkyl dihydrocarbyl phosphinate may be methyl diethylphosphinate, ethyl diethylphosphinate, or a mixture thereof.

[0020] In one embodiment, the dihydrocarbyl phosphinate alkyl ester comprises one or a combination of at least two of methyl dimethylphosphinate, methyl diethylphosphinate, methyl dipropylphosphinate, methyl ethylpropylphosphinate, methyl diphenylphosphinate, ethyl dimethylphosphinate, ethyl diethylphosphinate, ethyl dipropylphosphinate, ethyl ethylpropylphosphinate, propyl dimethylphosphinate, propyl diethylphosphinate, propyl dipropylphosphinate, propyl ethylpropylphosphinate, methylphenylphosphinate or methyl diphenylphosphinate.

[0021] The organic nitrogen-containing compound is selected from primary amines, secondary amines, and imines. In the present application, a primary amine is a derivative in which one hydrogen atom in an NH3 molecule is replaced by a (substituted) hydrocarbon group; a secondary amine is a derivative in which two hydrogen atoms in an NH3 molecule are replaced by (substituted) hydrocarbon groups; and an imine is structurally equivalent to a product obtained by condensing ammonia or a primary amine with an aldehyde or a ketone, and has an amine represented by the following formula (II).

[0022] Wherein, R4 and R5 are independently selected from hydrogen, substituted or unsubstituted alkyl, and substituted or unsubstituted aromatic groups.

[0023] The structures of the primary amines, secondary amines, and imines may contain multiple amino groups, imino groups, and / or -C=NH groups within the same molecule. For example, a primary amine may contain two amino groups, one amino group and one imino group, or one amino group and one -C=NH group. When multiple amino groups, imino groups, and / or -C=NH groups are present within the structure of a primary amine, secondary amine, or imine, dialkylphosphinate ammonium salts formed by alkylation of at least one of these nitrogen atoms with an alkyl dialkylphosphinate also fall within the scope of this application. In the present application, typical organic nitrogen-containing compounds include methylamine, ethylamine, propylamine, butylamine, pentylamine, hexylamine, heptylamine, octylamine, nonylamine, quinamine, dodecylamine, octadecylamine, cyclohexylamine, diethylamine, methylpropylamine, ethylenediamine, propylenediamine, butylenediamine, pentylenediamine, hexylenediamine, heptylenediamine, octanediamine, 1,4-cyclohexanediamine, diethanolamine, m-phenylenediamine, p-phenylenediamine, piperazine, 2-methylpiperazine, 2-methylimidazole, tetraethylenepentamine, triethylenetetramine, aniline, N-methylaniline, 4-methylaniline, diaminodiphenylmethane, 2,2-bis(4-aminophenyl)propane, diaminodiphenyl sulfone, diaminobenzophenone, cyanamide, melamine or dicyandiamide, or a combination of at least two thereof.

[0024] In one embodiment, the organic nitrogen-containing compound is a primary amine compound.

[0025] At least one of the nitrogen atoms in the dihydrocarbylphosphinate ammonium salt that has undergone the alkylation reaction has a hydrogen atom. After the reaction between the dihydrocarbylphosphinate alkyl ester and the organic nitrogen-containing compound is complete, at least one of the nitrogen atoms in the organic nitrogen portion of the dihydrocarbylphosphinate ammonium salt that has participated in the alkylation reaction still has at least one hydrogen atom.

[0026] In one embodiment, the dialkyl ammonium hypophosphite salt has any one of the following structures:

[0027] In the above formulae (III) to (XVIII), R1, R2, and R3 have the same definitions as R1, R2, and R3 in formula (I).

[0028] In one embodiment, in the above formula (III) to formula (XVIII), R1 is selected from C1 to C6 alkyl; R2 and R3 are independently selected from C1 to C 18 Straight chain or branched alkyl or C6~C 24 of aromatic groups.

[0029] In one embodiment, R1 is independently selected from methyl, ethyl, propyl, isopropyl or butyl; R2 and R3 are independently selected from methyl, ethyl, propyl, isopropyl, butyl or phenyl.

[0030] In one embodiment, R1 is selected from methyl, ethyl or propyl; R2 and R3 are independently selected from ethyl, propyl, isopropyl or butyl.

[0031] In one embodiment, R1 is selected from methyl, ethyl or propyl; R2 and R3 are ethyl.

[0032] On the other hand, the present application provides a method for preparing the dialkylphosphinate ammonium salt as described above, the preparation method comprising the following steps:

[0033] The dialkylphosphinate alkyl ester is subjected to an alkylation reaction with NH3 or the nitrogen on at least one non-tertiary amine structure in an organic nitrogen-containing compound to obtain the dialkylphosphinate ammonium salt.

[0034] When the organic nitrogen-containing compound contains multiple nitrogen atoms, one or more of them can participate in the alkylation reaction, but at least one of the nitrogen atoms still retains at least one hydrogen atom after participating in the alkylation reaction. For example, the organic nitrogen-containing compound used in this application may include primary amines, secondary amines, and imines containing tertiary amine structures. In this case, the nitrogen atoms in the tertiary amine structure can also be alkylated with the dialkylphosphinate alkyl ester, but at least one of the nitrogen atoms in the primary amines, secondary amines, and imines participating in the alkylation reaction still retains at least one hydrogen atom.

[0035] Typical dihydrocarbyl phosphinate alkyl esters include one or a combination of at least two of methyl dimethylphosphinate, methyl diethylphosphinate, methyl dipropylphosphinate, methyl ethylpropylphosphinate, methyl diphenylphosphinate, ethyl dimethylphosphinate, ethyl diethylphosphinate, ethyl dipropylphosphinate, ethyl ethylpropylphosphinate, propyl dimethylphosphinate, propyl diethylphosphinate, propyl dipropylphosphinate, propyl ethylpropylphosphinate, methylphenylphosphinate or methyl diphenylphosphinate.

[0036] In one embodiment, the organic nitrogen-containing compound comprises methylamine, ethylamine, propylamine, butylamine, pentylamine, hexylamine, heptylamine, octylamine, nonylamine, quinoline, dodecylamine, octadecylamine, cyclohexylamine, diethylamine, methylpropylamine, ethylenediamine, propylenediamine, butylenediamine, pentylenediamine, hexylenediamine, heptylenediamine, octanediamine, 1,4-cyclohexanediamine, diethanolamine, m-phenylenediamine, p-phenylenediamine, piperazine, 2-methylpiperazine, 2-methylimidazole, tetraethylenepentamine, triethylenetetramine, aniline, N-methylaniline, 4-methylaniline, diaminodiphenylmethane, 2,2-bis(4-aminophenyl)propane, diaminodiphenyl sulfone, diaminobenzophenone, cyanamide, melamine or dicyandiamide, or a combination of at least two thereof.

[0037] In the present application, the molar ratio of the organic nitrogen-containing compound to the alkyl dihydrocarbylphosphinate is determined by the total amount of nitrogen in the organic nitrogen-containing compound.

[0038] In one embodiment, the molar ratio of the sum of the moles of nitrogen in the organic nitrogen-containing compound to the alkyl dialkyl phosphinate is 10 / 1-1 / 10, for example, 10 / 1, 9 / 1, 8 / 1, 7 / 1, 6 / 1, 5 / 1, 4 / 1, 3 / 1, 2 / 1, 1 / 1, 1 / 2, 1 / 3, 1 / 4, 1 / 5, 1 / 6, 1 / 7, 1 / 8, 1 / 9 or 1 / 10. If the ratio is too small, the flame retardancy of the obtained product is poor; if the ratio is too high, the excess alkyl dialkyl phosphinate needs to be recovered, which reduces the economic efficiency.

[0039] In one embodiment, the molar ratio of the sum of the moles of nitrogen in the organic nitrogen-containing compound to the alkyl dihydrocarbyl phosphinate is 6 / 1-1 / 6; for example, it can be 5 / 1-1 / 6; 4 / 1-1 / 6; 3 / 1-1 / 6; 2 / 1-1 / 6; 1 / 1-1 / 6; 1 / 1-1 / 5; 1 / 1-1 / 4; 1 / 1-1 / 3, 1 / 1-1 / 2.5 or 1 / 1-1 / 2.

[0040] In one embodiment, the alkylation reaction temperature is 0-250°C, such as 0°C, 10°C, 50°C, 80°C, 100°C, 150°C, 180°C, 200°C, 220°C or 250°C.

[0041] In one embodiment, the alkylation reaction time is 0.1-30 hours, such as 0.1 hours, 3 hours, 5 hours, 8 hours, 10 hours, 13 hours, 15 hours, 18 hours, 20 hours, 23 hours, 25 hours, 28 hours or 30 hours.

[0042] In the present application, the alkylation reaction can be carried out under normal pressure, negative pressure or positive pressure.

[0043] When the organic nitrogen-containing compound contains two or more reactive nitrogen groups, the product can be a product in which all or part of the nitrogen groups are alkylated, or a mixture of these products. For example, the reaction of diaminodiphenylmethane and methyl diethylphosphinate can produce compounds having structural formulas (III) and (IV), respectively, or a mixture thereof.

[0044] On the other hand, the present application provides a flame-retardant polymer material, which includes a flame retardant and a polymer material, wherein the flame retardant includes the dialkylphosphinate ammonium salt described above.

[0045] In one embodiment, the flame retardant polymer material comprises 0.1-50 wt % of a flame retardant and 50-99.9 wt % of a polymer material.

[0046] In the present application, the mass content of the flame retardant in the flame retardant polymer material is independently selected from any value among 0.1%, 0.2%, 0.5%, 0.8%, 1%, 1.2%, 1.5%, 2%, 2..2%, 2.5%, 3%, 3.5%, 4%, 5%, 6%, 8%, 10%, 15%, 20%, 30%, 40% or 50%, or any range value between two of them.

[0047] In one embodiment, the flame retardant polymer material further includes a functional additive.

[0048] In one embodiment, the functional additive is selected from at least one of a reinforcing agent, an anti-dripping agent, a stabilizer, a pigment, a dye, a carbon-forming catalyst, a dispersant, a nucleating agent, an inorganic filler, an organic filler or an antioxidant.

[0049] In one embodiment, the reinforcing agent is selected from glass fibers.

[0050] In one embodiment, the anti-drip agent is selected from Teflon.

[0051] In one embodiment, the inorganic filler is selected from at least one of silicon dioxide, mica, calcium carbonate, aluminum oxide, aluminum nitride, talc, calcium oxide, calcium silicate, glass fiber powder or silica.

[0052] In one embodiment, the organic filler is selected from at least one of polytetrafluoroethylene powder, polyphenylene sulfide powder, and polyethersulfone powder.

[0053] In one embodiment, the mass content of the functional additive in the flame retardant polymer material is 5-40%; for example, 5%, 8%, 10%, 15%, 18%, 20%, 25%, 28%, 30%, 33%, 35%, 38% or 40%.

[0054] In one embodiment, the flame retardant polymer material further includes a flame retardant Q.

[0055] In one embodiment, the flame retardant Q is selected from at least one of a phosphorus-based flame retardant, a nitrogen-based flame retardant, and a boron-based flame retardant.

[0056] In one embodiment, the phosphorus-based flame retardant is selected from at least one of bisphosphates, phosphazenes, dialkyl phosphinates, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide derivatives (such as 6H-dibenzo[c,e][1,2]oxophosphoglycerate, 6,6'-(1,2-ethanediyl)bis-6,6'-dioxide and HTP-6123 of Guizhou Yuanyi Group), and phosphine oxide compounds.

[0057] In one embodiment, the bisphosphate is selected from at least one of bisphenol A bisdiphenyl phosphate, resorcinol bisdiphenyl phosphate, and 1,3-phenylene (2,6-xylyl)tetraphosphate.

[0058] In one embodiment, the phosphazene flame retardant is selected from at least one of hexaphenoxycyclotriphosphazene, cyanophenoxyphosphazene (such as FP-300 of Fushimi Pharmaceutical Co., Ltd. of Japan), allyl cyclophosphazene (such as SPV-100 of Otsuka of Japan) or cyclic biphenyloxyphosphazene (such as BP-PZ of Otsuka of Japan).

[0059] In one embodiment, the dihydrocarbyl phosphinate is at least one selected from aluminum diethylphosphinate, aluminum diisobutylphosphinate, aluminum dipropylphosphinate, and zinc diethylphosphinate.

[0060] In one embodiment, the 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide derivative is selected from at least one of 6H-dibenzo[c,e][1,2]oxaphosphatinane-6,6'-(1,4-ethanediyl)bis-6,6'-dioxide and 6H-dibenzo[c,e][1,2]oxaphosphatinane-6,6'-(1,4-phenylethanediyl)bis-6,6'-dioxide.

[0061] In one embodiment, the phosphine oxide compound is p-xylylbisdiphenylphosphine oxide (eg, PQ-60 from Jinyi Chemical).

[0062] In one embodiment, the nitrogen-based flame retardant is selected from at least one of melamine cyanurate, melamine polyphosphate, and ammonium polyphosphate.

[0063] In one embodiment, the boron-based flame retardant is selected from zinc borate.

[0064] In one embodiment, the mass content of the flame retardant Q in the flame retardant polymer material is 0.5-20%, for example, 0.5%, 0.8%, 1%, 3%, 5%, 8%, 10%, 13%, 15%, 18% or 20%.

[0065] In one embodiment, the polymer material is selected from thermoplastic polymer resin or thermosetting resin.

[0066] In one embodiment, the thermoplastic polymer resin is selected from at least one of polybutadiene, polyamide, polyester, polyphenylene ether, acrylonitrile-butadiene-styrene copolymer, polyethylene, polypropylene, polyvinyl chloride, polystyrene, polyimide, polyphenylene sulfide or polyetheretherketone.

[0067] In one embodiment, the thermosetting resin is selected from at least one of vinyl polyphenylene ether resin, epoxy resin, cyanate resin, BT resin, bismaleimide resin, phenolic resin, polyurethane resin, thermosetting polyimide, unsaturated polyester resin, vinyl resin, benzoxazine resin, aromatic acetylene resin or furan resin.

[0068] In one embodiment, the thermosetting resin is at least one of vinyl polyphenylene ether resin, epoxy resin, cyanate resin, BT resin, bismaleimide resin, and thermosetting polyimide.

[0069] In one embodiment, the thermosetting resin is an epoxy resin.

[0070] In one embodiment, the epoxy resin is selected from at least one of bisphenol A epoxy resin, bisphenol F epoxy resin, dicyclopentadiene epoxy resin, biphenyl epoxy resin or naphthol epoxy resin.

[0071] The epoxy resins described in this application include but are not limited to epoxy resins currently available on the market.

[0072] In one embodiment, the flame-retardant polymer material of the present application is a flame-retardant epoxy resin material, which includes a flame retardant and an epoxy resin, and the flame retardant includes the dialkylphosphinate ammonium salt described above.

[0073] In one embodiment, the flame retardant epoxy resin material comprises 0.1-18 wt % of dialkylphosphinate ammonium salt and 82-99.9 wt % of epoxy resin.

[0074] In one embodiment, the content of the flame retardant having the structure of formula (I) in the flame retardant material is 0.1%, 0.2%, 0.5%, 0.8%, 1%, 1.2%, 1.5%, 2%, 2..2%, 2.5%, 3%, 3.5%, 4%, 5%, 6%, 8%, 10%, 15%, 18% by weight or any range between two values.

[0075] In one embodiment, the flame retardant epoxy resin material further includes a functional additive;

[0076] In one embodiment, the functional additive is selected from at least one of a reinforcing agent, an anti-dripping agent, a stabilizer, a pigment, a dye, a carbon-forming catalyst, a dispersant, a nucleating agent, an inorganic filler, an organic filler or an antioxidant.

[0077] In one embodiment, the reinforcing agent is selected from glass fibers.

[0078] In one embodiment, the anti-drip agent is selected from Teflon.

[0079] In one embodiment, the inorganic filler is selected from at least one of silicon dioxide, mica, calcium carbonate, aluminum oxide, aluminum nitride, talc, calcium oxide, calcium silicate, glass fiber powder or silica.

[0080] In one embodiment, the organic filler is selected from at least one of polytetrafluoroethylene powder, polyphenylene sulfide powder, and polyethersulfone powder.

[0081] In one embodiment, the mass content of the functional additive in the flame retardant epoxy resin material is 5-40%, for example, 5%, 8%, 10%, 15%, 18%, 20%, 25%, 28%, 30%, 33%, 35%, 38% or 40%.

[0082] The dialkyl ammonium hypophosphite salt prepared in the present application is simple to prepare and is suitable for industrial large-scale production. When applied to epoxy resin, it has high flame retardant efficiency and can effectively maintain the physical properties of the epoxy resin.

[0083] Compared with the prior art, this application has the following advantages:

[0084] The dialkylphosphinic acid ammonium salt described in the present application has a lower melting point than the solid amine used to prepare it, is easy to liquefy, has good compatibility with the resin, has a fast compatibility speed, and is easy to operate. It not only overcomes the high melting point, difficulty in liquefaction, and poor compatibility with the resin system of solid amines, but also overcomes the problems of corrosiveness caused by dialkylphosphinic acid or its residues.

[0085] The dialkylphosphinate ammonium salt of the present application, as a flame retardant, not only has high flame retardant efficiency, but also can effectively maintain the physical properties of polymer materials, especially the glass transition temperature.

[0086] The dialkylphosphinate ammonium salt of the present application is simple to prepare, does not require a solvent, and is catalyst-free. It is a 1+1=2 reaction, has high atom economy, and is suitable for large-scale production.

[0087] Still other aspects will become apparent upon reading and understanding the accompanying drawings and detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0088] The accompanying drawings are used to provide a further understanding of the technical solution of this article and constitute a part of the specification. Together with the embodiments of this application, they are used to explain the technical solution of this article and do not constitute a limitation on the technical solution of this article.

[0089] Figure 1 is the H NMR spectrum of DDM-MDP-1-2.

[0090] Figure 2 is the H NMR spectrum of melamine-MDP-1-3.

[0091] Figure 3 is the H NMR spectrum of TEPA-MDP-1-5. DETAILED DESCRIPTION

[0092] The technical solution of the present application is further described below through specific implementation methods. Those skilled in the art should understand that the embodiments are only used to help understand the present application and should not be regarded as specific limitations of the present application.

[0093] The raw materials used in the embodiment are as follows:

[0094] Melamine: Sinopharm Chemical Reagent Co., Ltd.

[0095] Dicyandiamide (DICY): Shanghai Aladdin Biochemical Technology Co., Ltd.

[0096] Diaminodiphenylmethane (DDM): Shanghai Aladdin Biochemical Technology Co., Ltd.

[0097] Tetraethylenepentamine (TEPA): Shanghai MacLean Biochemical Technology Co., Ltd.

[0098] Methyl diethylphosphinate (MDP): Jiangsu Liside New Materials Co., Ltd.

[0099] E44 epoxy resin (DGEBA): Baling Petrochemical Co., Ltd.

[0100] Novolac epoxy resin SQPN-O48 (F48): Shandong Shengquan Chemical Co., Ltd.

[0101] 2-Methylimidazole: San Chemical Technology (Shanghai) Co., Ltd.

[0102] N,N-Dimethylformamide (DMF): Shanghai Aladdin Biochemical Technology Co., Ltd.

[0103] Combustion test standard: GB / T 2408 2008

[0104] Example 1 Preparation of a product of melamine and methyl diethylphosphinate in a 1 / 4 molar ratio

[0105] Melamine and diethyl methyl hypophosphite are reacted in a molar ratio of 1:4. The specific reaction operation is as follows:

[0106] 2 g (0.016 mol) of melamine (melting point 354°C) and 13.9 g (0.102 mol) of diethyl methyl phosphite were mixed and reacted at 200°C for 6 h. Excess diethyl methyl phosphite was removed by distillation under reduced pressure, and the mixture was dried under vacuum at 160°C to yield 10.5 g (98.9%) of a yellow viscous liquid. This was designated melamine-MDP-1-4. 1 H NMR, DMSO-d6 as solvent: 2.6-3.6 ppm (N-CH3, 12H), 1.3-2.0 ppm (-CH2CH3, 16H), 0.8-1.2 ppm (-CH2CH3, 24H). It has the following structure:

[0107] Example 2 Preparation of a product of melamine and methyl diethylphosphinate in a 1 / 3 molar ratio

[0108] Melamine and diethyl methyl hypophosphite are reacted in a molar ratio of 1:3. The specific reaction operation is as follows:

[0109] 10g (0.08mol) of melamine (melting point 354°C) was mixed with 32.35g (0.24mol) of diethyl methyl hypophosphite and reacted at 200°C for 6h to yield 36g (85.0%, transfer loss) of a pale yellow liquid. This was designated melamine-MDP-1-3. The H NMR spectrum is shown in Figure 2. 1H NMR, DMSO-d6 as solvent: 2.6-3.6 ppm (N-CH3, 9H), 1.3-2.0 ppm (-CH2CH3, 12H), 0.8-1.2 ppm (-CH2CH3, 18H). It has the following structure:

[0110] Example 3 Preparation of a product of dicyandiamide and methyl diethylphosphinate in a 1 / 2 molar ratio

[0111] Dicyandiamide and diethyl methyl hypophosphite are reacted in a molar ratio of 1:2. The specific reaction operation is as follows:

[0112] 5 g (0.06 mol) of dicyandiamide (209.5°C) was mixed with 17.8 g (0.13 mol) of diethyl methyl phosphinate, reacted at 180-190°C for 4 h, and dried under vacuum at 160°C to obtain 18.3 g (86.4%, transfer loss) of a yellow transparent liquid, designated DICY-MDP-1-2. 1 H NMR, DMSO-d6 as solvent: 2.6-3.7 ppm (N-CH3, 6H), 1.3-1.5 ppm (-CH2CH3, 8H), 0.8-1.1 ppm (-CH2CH3, 12H). It has the following structure:

[0113] mixture.

[0114] Example 4 Preparation of a product of a 1 / 3 molar ratio of dicyandiamide and methyl diethylphosphinate

[0115] Dicyandiamide and diethyl methyl hypophosphite react at a molar ratio of 1:3. The specific reaction operation is as follows:

[0116] 5 g (0.06 mol) of dicyandiamide (209.5°C) was mixed with 26.7 g (0.2 mol) of diethyl methyl hypophosphite, reacted at 190°C for 6 h, and dried under vacuum at 160°C to obtain 27.1 g (92.6%, transfer loss) of a yellow transparent liquid, designated as DICY-MDP-1-3. 1 H NMR, DMSO-d6 as solvent: 2.6-3.7 ppm (N-CH3, 9H), 1.3-1.5 ppm (-CH2CH3, 12H), 0.8-1.1 ppm (-CH2CH3, 18H). It has the following structure:

[0117] Example 5 Preparation of a product of a 1 / 2 molar ratio of diaminodiphenylmethane and methyl diethylphosphinate

[0118] 4,4-Diaminodiphenylmethane and diethyl methyl hypophosphite are reacted at a molar ratio of 1:2. The specific reaction operation is as follows:

[0119] 10g (0.05mol) of 4,4-diaminodiphenylmethane (melting point 89-91°C) was mixed with 13.31g (0.10mol) of diethyl methyl hypophosphite and heated at 160°C. The reaction continued for approximately 1.5h to yield 22.84g (98.0%) of a wine-red liquid. This was designated DDM-MDP-1-2. The H NMR spectrum is shown in Figure 1. 1 H NMR, DMSO-d6 as solvent: 6.3-7.2 ppm (Ph-H, NH, 12H), 3.6 ppm (Ph-CH2-Ph, 2H); 2.8-3.0 ppm (N-CH3, 6H), 1.7 ppm (-CH2CH3, 8H), 1.2 ppm (-CH2CH3, 12H). It has the following structure:

[0120] Example 6 Preparation of a product of a 1 / 2 molar ratio of diaminodiphenylmethane and ethyl diethylphosphinate

[0121] Preparation of ethyl diethyl hypophosphite: 100 g (0.6 mol) of triethyl orthoacetate and 75.2 g (0.6 mol) of diethyl hypophosphite were mixed, reacted at 100-110°C for 20 h, and by-products were removed by distillation at 100°C to obtain 88 g (97.8%) of ethyl diethyl hypophosphite (EDP). 1 H NMR, CDCl3 as solvent: 3.9 ppm (PO-CH2CH3, 2H), 1.6 ppm (-CH2CH3, 4H), 1.2 ppm (PO-CH2CH3, 3H), 1.1 ppm (-CH2CH3, 6H). It has the following structure:

[0122] 4,4-Diaminodiphenylmethane and diethyl phosphite were reacted in a molar ratio of 1:2. The specific reaction procedure was as follows: 10 g (0.05 mol) of 4,4-diaminodiphenylmethane (melting point 89-91°C) was mixed with 14.82 g (0.10 mol) of diethyl phosphite, and the mixture was heated to 200°C. The reaction was continued for approximately 3 hours to yield 23.98 g (97.0%) of a wine-red liquid. This was designated DDM-EDP-1-2. 1 H NMR, DMSO-d6 as solvent: 6.3-7.2 ppm (Ph-H, 8H), 3.6 ppm (Ph-CH2-Ph, 2H); 2.8-3.4 ppm (N-CH2CH3, 4H), 1.7 ppm (-CH2CH3, 8H), 1.2 ppm (-CH2CH3, N-CH2CH3, 18H). It has the following structure:

[0123] Example 7 Preparation of a product of tetraethylenepentamine and methyl diethylphosphinate in a 1 / 5 molar ratio

[0124] Tetraethylenepentamine and diethyl methyl hypophosphite are reacted at a molar ratio of 1:5. The specific reaction operation is as follows:

[0125] 5g (0.026 mol) of tetraethylenepentamine (melting point -40°C) was mixed with 17.4g (0.128 mol) of diethyl methyl hypophosphite, reacted at 150°C for 1 hour, and dried under vacuum at 160°C to yield 20.28g (91.9%, transfer loss) of a yellow, transparent liquid. This was designated TEPA-MDP-1-5. The H NMR spectrum is shown in Figure 3. 1 H NMR, DMSO-d6 as solvent: 2.0-4.0 ppm (N-CH3, -CH2CH2-, 31H), 1.3-1.5 ppm (-CH2CH3, 20H), 0.8-1.1 ppm (-CH2CH3, 30H). It has the following structure:

[0126] Example 8

[0127] Heat 79.6 parts of epoxy resin DGEBA to 80°C. Once fully softened, add 17.4 parts of 4,4-diaminodiphenylmethane (DDM) and stir rapidly to dissolve the DDM. Once most of the DDM has dissolved, add 3 parts of melamine-MDP-1-4 (prepared in Example 1) and continue stirring for 1 minute to form a uniform mixture. While still hot, pour the mixture into a mold preheated at 80°C. Let it stand for 10 minutes, then heat to 120°C for pre-curing for 2 hours, then heat to 170°C for curing for 4 hours. Cool naturally to room temperature to obtain a 3wt% EP / melamine-MDP-1-4 composite material. The sample thickness is 3.2mm. It meets the UL94 V0 rating. The Tg is 151°C. The results are shown in Table 1.

[0128] Example 9

[0129] Heat 80.4 parts of epoxy resin DGEBA to 80°C. Once fully softened, add 17.6 parts of 4,4-diaminodiphenylmethane (DDM) and stir rapidly to dissolve the DDM. Once most of the DDM has dissolved, add 2 parts of melamine-MDP-1-4 (prepared in Example 1) and continue stirring for 1 minute to form a uniform mixture. While still hot, pour the mixture into a mold preheated at 80°C. Let it stand for 10 minutes, then heat to 120°C for pre-curing for 2 hours, then heat to 170°C for curing for 4 hours. Allow to cool naturally to room temperature to obtain a 2 wt% EP / melamine-MDP-1-4 composite material. The sample thickness is 3.2 mm. It meets the UL94V1 rating. Results are shown in Table 1.

[0130] Example 10

[0131] Heat 79.6 parts of epoxy resin DGEBA to 80°C. Once fully softened, add 17.4 parts of 4,4-diaminodiphenylmethane (DDM) and stir rapidly to dissolve the DDM. Once most of the DDM has dissolved, add 3 parts of melamine-MDP-1-3 (prepared in Example 2) and continue stirring for 1 minute to form a uniform mixture. While still hot, pour the mixture into a mold preheated at 80°C. Let it stand for 10 minutes, then heat to 120°C for pre-curing for 2 hours, then heat to 170°C for curing for 4 hours. Cool naturally to room temperature to obtain a 3wt% EP / melamine-MDP-1-3 composite material. The sample thickness is 3.2mm. It meets the UL94 V0 rating. The Tg is 150°C. The results are shown in Table 1.

[0132] Example 11

[0133] Heat 80.4 parts of epoxy resin DGEBA to 80°C. Once fully softened, add 17.6 parts of 4,4-diaminodiphenylmethane (DDM) and stir rapidly to dissolve the DDM. Once most of the DDM has dissolved, add 2 parts of melamine-MDP-1-3 (prepared in Example 2) and continue stirring for 1 minute to form a uniform mixture. While still hot, pour the mixture into a mold preheated at 80°C. Let it stand for 10 minutes, then heat to 120°C for pre-curing for 2 hours, then heat to 170°C for curing for 4 hours. Allow to cool naturally to room temperature to obtain a 2 wt% EP / melamine-MDP-1-3 composite material. The sample thickness is 3.2 mm. It meets the UL94V1 rating. Results are shown in Table 1.

[0134] Example 12

[0135] Heat 79.6 parts of epoxy resin DGEBA to 80°C. Once fully softened, add 17.4 parts of 4,4-diaminodiphenylmethane (DDM) and stir rapidly to dissolve the DDM. Once most of the DDM has dissolved, add 3 parts of DICY-MDP-1-2 (prepared in Example 3) and continue stirring for 1 minute to form a uniform mixture. While still hot, pour the mixture into a mold preheated at 80°C. Let it stand for 10 minutes, then heat to 120°C for pre-curing for 2 hours, then heat to 170°C for curing for 4 hours. Allow to cool naturally to room temperature to obtain a 3wt% EP / DICY-MDP-1-2 composite material. The sample thickness is 3.2mm. It meets the UL94 V0 rating. The Tg is 147°C. The results are shown in Table 1.

[0136] Example 13

[0137] Heat 80.4 parts of epoxy resin DGEBA to 80°C. Once fully softened, add 17.6 parts of 4,4-diaminodiphenylmethane (DDM) and stir rapidly to dissolve the DDM. Once most of the DDM has dissolved, add 2 parts of DICY-MDP-1-2 (prepared in Example 3) and continue stirring for 1 minute to form a uniform mixture. While still hot, pour the mixture into a mold preheated at 80°C. Let it stand for 10 minutes, then heat to 120°C for pre-curing for 2 hours, then heat to 170°C for curing for 4 hours. Allow to cool naturally to room temperature to obtain a 2 wt% EP / DICY-MDP-1-2 composite material. The sample thickness is 3.2 mm. It meets the UL94V1 rating. Results are shown in Table 1.

[0138] Example 14

[0139] Heat 80.4 parts of epoxy resin DGEBA to 80°C. Once fully softened, add 17.6 parts of 4,4-diaminodiphenylmethane (DDM) and stir rapidly to dissolve the DDM. Once most of the DDM has dissolved, add 2 parts of DICY-MDP-1-3 (prepared in Example 4) and continue stirring for 1 minute to form a uniform mixture. While still hot, pour the mixture into a mold preheated at 80°C. Let it stand for 10 minutes, then heat to 120°C for pre-curing for 2 hours, then heat to 170°C for curing for 4 hours. Allow to cool naturally to room temperature to obtain a 2 wt% EP / DICY-MDP-1-3 composite material. The sample thickness is 3.2 mm. It meets the UL94 V0 rating. The Tg is 153°C. The results are shown in Table 1.

[0140] Example 15

[0141] Heat 81.3 parts of epoxy resin DGEBA to 80°C. Once fully softened, add 17.7 parts of 4,4-diaminodiphenylmethane (DDM) and stir rapidly to dissolve the DDM. Once most of the DDM has dissolved, add 1 part of DICY-MDP-1-3 (prepared in Example 4) and continue stirring for 1 minute to form a uniform mixture. While still hot, pour the mixture into a mold preheated at 80°C. Let it stand for 10 minutes, then heat to 120°C for pre-curing for 2 hours, then heat to 170°C for curing for 4 hours. Allow to cool naturally to room temperature to obtain a 1 wt% EP / DICY-MDP-1-3 composite material. The sample thickness is 3.2 mm. It meets the UL94V1 rating. Results are shown in Table 1.

[0142] Example 16

[0143] Heat 78.8 parts of epoxy resin DGEBA to 80°C. Once fully softened, add 17.2 parts of 4,4-diaminodiphenylmethane (DDM) and stir rapidly to dissolve the DDM. Once most of the DDM has dissolved, add 4 parts of DDM-MDP-1-2 (prepared in Example 5) and continue stirring for 1 minute to form a uniform mixture. While still hot, pour the mixture into a mold preheated at 80°C. Let it stand for 10 minutes, then heat to 120°C for pre-curing for 2 hours, then heat to 170°C for curing for 4 hours. Allow to cool naturally to room temperature to obtain a 4 wt% EP / DDM-MDP-1-2 composite material. The sample thickness is 3.2 mm. It meets the UL94 V0 rating. The Tg is 145°C. The results are shown in Table 1.

[0144] Example 17

[0145] Heat 79.6 parts of epoxy resin DGEBA to 80°C. Once fully softened, add 17.4 parts of 4,4-diaminodiphenylmethane (DDM) and stir rapidly to dissolve the DDM. Once most of the DDM has dissolved, add 3 parts of DDM-MDP-1-2 (prepared in Example 5) and continue stirring for 1 minute to form a uniform mixture. While still hot, pour the mixture into a mold preheated at 80°C. Let it stand for 10 minutes, then heat to 120°C for pre-curing for 2 hours, then heat to 170°C for curing for 4 hours. Allow to cool naturally to room temperature to obtain a 3wt% EP / DDM-MDP-1-2 composite material. The sample thickness is 3.2mm. It meets the UL94V1 rating. Results are shown in Table 1.

[0146] Example 18

[0147] Heat 81.0 parts of epoxy resin DGEBA to 80℃, add 15.0 parts of 4,4-diaminodiphenylmethane (DDM) after it is fully softened, and stir rapidly to promote the dissolution of DDM; after most of the DDM is dissolved, add 4 parts of DDM-MDP-1-2 (prepared in Example 5, replacing part of DDM according to the functionality of 4), continue stirring for 1 minute to form a uniform mixed solution; pour the mixed solution into a mold preheated at 80℃ while it is hot, let it stand for 10 minutes, then heat it to 120℃ for pre-curing for 2 hours, and then heat it to 170℃ for curing for 4 hours. Cool it naturally to room temperature to obtain an EP / DDM-MDP-1-2-react-4 composite material with an addition amount of 4wt%. Reach UL94V0 grade. Soxhlet extraction is performed with dichloromethane. After 24 hours, the extract is 1 H and 31 P NMR examination showed no DDM-MDP-1-2, indicating that DDM-MDP-1-2 was involved in the curing process.

[0148] Example 19

[0149] Heat 80.1 parts of epoxy resin DGEBA to 80°C. Once fully softened, add 16.9 parts of 4,4-diaminodiphenylmethane (DDM) and stir rapidly to dissolve the DDM. Once most of the DDM has dissolved, add 3 parts of DDM-MDP-1-2 (prepared in Example 2, with a functionality of 2 replacing some of the DDM). Continue stirring for 1 minute to form a uniform mixture. While still hot, pour the mixture into a mold preheated at 80°C. Let it stand for 10 minutes, then heat to 120°C for pre-curing for 2 hours, then heat to 180°C for curing for 4 hours. Allow to cool naturally to room temperature to obtain a 3wt% EP / DDM-MDP-1-2-react-2 composite material. It achieves a UL94 V0 rating and a Tg of 150°C. Results are shown in Table 1.

[0150] Example 20

[0151] Heat 78.8 parts of epoxy resin DGEBA to 80°C. Once fully softened, add 17.2 parts of 4,4-diaminodiphenylmethane (DDM) and stir rapidly to dissolve the DDM. Once most of the DDM has dissolved, add 4 parts of DDM-EDP-1-2 (prepared in Example 6) and continue stirring for 1 minute to form a uniform mixture. While still hot, pour the mixture into a mold preheated at 80°C. Let it stand for 10 minutes, then heat to 120°C for pre-curing for 2 hours, then heat to 170°C for curing for 4 hours. Allow to cool naturally to room temperature to obtain a 4 wt% EP / DDM-EDP-1-2 composite material. The sample thickness is 3.2 mm. It meets the UL94 V0 rating. The Tg is 146°C. The results are shown in Table 1.

[0152] Example 21

[0153] Heat 79.6 parts of epoxy resin DGEBA to 80°C. Once fully softened, add 17.2 parts of 4,4-diaminodiphenylmethane (DDM) and stir rapidly to dissolve the DDM. Once most of the DDM has dissolved, add 3 parts of DDM-EDP-1-2 (prepared in Example 6) and continue stirring for 1 minute to form a uniform mixture. While still hot, pour the mixture into a mold preheated at 80°C. Let it stand for 10 minutes, then heat to 120°C for pre-curing for 2 hours, then heat to 170°C for curing for 4 hours. Allow to cool naturally to room temperature to obtain a 3 wt% EP / DDM-EDP-1-2 composite material. The sample thickness is 3.2 mm. It meets the UL94V1 rating. Results are shown in Table 1.

[0154] Example 22

[0155] Heat 79.6 parts of epoxy resin DGEBA to 80°C. Once fully softened, add 17.4 parts of 4,4-diaminodiphenylmethane (DDM) and stir rapidly to dissolve the DDM. Once most of the DDM has dissolved, add 3 parts of TEPA-MDP-1-5 (prepared in Example 7) and continue stirring for 1 minute to form a uniform mixture. While still hot, pour the mixture into a mold preheated at 80°C. Allow to stand for 10 minutes, then heat to 120°C for pre-curing for 2 hours, then heat to 170°C for curing for 4 hours. Allow to cool naturally to room temperature to obtain a 3 wt% EP / TEPA-MDP-1-5 composite material. The sample thickness is 3.2 mm. It meets the UL94 V0 rating and has a Tg of 148°C. Results are shown in Table 1.

[0156] Example 23

[0157] Heat 80.4 parts of epoxy resin DGEBA to 80°C. Once fully softened, add 17.6 parts of 4,4-diaminodiphenylmethane (DDM) and stir rapidly to dissolve the DDM. Once most of the DDM has dissolved, add 2 parts of TEPA-MDP-1-5 (prepared in Example 7) and continue stirring for 1 minute to form a uniform mixture. While still hot, pour the mixture into a mold preheated at 80°C. Allow to stand for 10 minutes, then heat to 120°C for a pre-cure of 2 hours, then heat to 170°C for a cure of 4 hours. Allow to cool naturally to room temperature to obtain a 2 wt% EP / TEPA-MDP-1-5 composite. The sample thickness is 3.2 mm. It meets the UL94V1 rating. Results are shown in Table 1.

[0158] Example 24

[0159] 83.2 parts of F48 epoxy resin, 8.7 parts of dicyandiamide, 0.1 parts of 2-methylimidazole, and 8 parts of DICY-MDP-1-3 (prepared in Example 4) were mixed. N,N-dimethylformamide (DMF) was added in an amount equal to the amount of dicyandiamide to promote dissolution. The mixture was heated at 100°C with stirring. Once a homogeneous solution was formed, the DMF was removed in a 100°C vacuum oven. Finally, the mixture was poured into a mold preheated at 100°C, precured at 130°C for 1 hour, and cured at 170°C for 4 hours to produce an EP-F48 / DICY-MDP-1-3 composite material with an 8% addition. The sample thickness was 3.2 mm. The UL94 V0 rating was achieved. The results are shown in Table 1.

[0160] Example 25

[0161] 83.2 parts of F48 epoxy resin, 8.7 parts of dicyandiamide, 0.1 part of 2-methylimidazole, and 8 parts of TEPA-MDP-1-5 (prepared in Example 7) were mixed. N,N-dimethylformamide (DMF) was added in an amount equal to the amount of dicyandiamide to promote dissolution. The mixture was heated at 100°C with stirring. Once a homogeneous solution was formed, the DMF was removed in a 100°C vacuum oven. Finally, the mixture was poured into a mold preheated at 100°C, precured at 130°C for 1 hour, and cured at 170°C for 4 hours to produce an 8% EP-F48 / TEPA-MDP-1-5 composite material. The sample thickness was 3.2 mm. The UL94 V0 rating was achieved. The results are shown in Table 1.

[0162] Example 26

[0163] After drying polypropylene (PP) in an 80°C forced air oven for 4 hours, 80 parts PP and 20 parts DICY-MDP-1-3 (prepared in Example 4) were melted in an internal mixer at 50 rpm, set to 200°C, and after 6 minutes, cooled and dried. The mixture was then filled into a mold and preheated for 10 minutes at 200°C on a flat-plate vulcanizer, maintaining a pressure of 10 MPa for 5 minutes, followed by cold pressing. After cooling, samples were cut and tested. The sample thickness was 3.2 mm. UL94 V0 rating was achieved.

[0164] Comparative Example 1

[0165] 4,4-Diaminodiphenylmethane: Diethyl hypophosphorous acid (1:2): Add 5 g (0.025 mol) of 4,4-diaminodiphenylmethane in portions to 5.97 g (0.049 mol) of diethyl hypophosphorous acid. Allow to react at 80-100°C. The reaction is complete when the 4,4-diaminodiphenylmethane dissolves completely. The product, DDM-DEP-1-2, is 10.4 g (94.8%, transfer loss) of yellow liquid. It slowly crystallizes at room temperature to form a yellow-green solid. It absorbs moisture easily in air, making it difficult to use. 1H NMR: 7.0 ppm (Ph-H, 4H), 6.8 ppm (NH, 6H), 6.7 ppm (Ph-H, 4H), 3.8 ppm (Ph-CH2-Ph, 2H), 1.7 ppm (-CH2CH3, 8H), 1.2 ppm (-CH2CH3, 12H). It has the structure shown below:

[0166] Comparative Example 2

[0167] Melamine / diethylphosphite reaction in a 1:3 ratio: 5g (0.04 mol) of melamine was mixed with 14.51g (0.12 mol) of diethylphosphite and reacted at 190-200°C for 2 hours to yield 17.55g (89.9%, transfer loss) of melamine-DEP-1-3 as a pale yellow paste. Melamine-DEP-1-3 exhibits poor compatibility with DGEBA, with most of the solid remaining in the EP after curing. 1 H NMR: 6.0-11.0 ppm (NH, 9H), 1.3-1.5 ppm (-CH2CH3, 12H), 0.8-1.1 ppm (-CH2CH3, 18H). It has the following structure:

[0168] Comparative Example 3

[0169] A 1:2 reaction of dicyandiamide and diethylphosphorous acid: 5g (0.07 mol) of dicyandiamide was mixed with 14.51g (0.12 mol) of diethylphosphorous acid and reacted at 100°C. pH paper was used to detect alkaline gas in the exhaust gas. Nuclear magnetic resonance (NMR) results indicated that the reaction mixture consisted of dicyandiamide, diethylphosphorous acid, and the product, DICY-DEP-1-2, along with a large amount of byproducts. Pure DICY-DEP-1-2 could not be obtained.

[0170] Comparative Example 4

[0171] Dicyandiamide and diethyl hypophosphorous acid react in a ratio of 1:2: 5 g (0.07 mol) of dicyandiamide and 14.51 g (0.12 mol) of diethyl hypophosphorous acid are mixed and dissolved in 30 g of water. The mixture is reacted at 70°C for 30 min to obtain a DICY-DEP-1-2 aqueous solution. The water is removed by rotary evaporation at 70°C, and the product decomposes. 31 The peak of diethyl hypophosphorous acid reappeared in the P NMR results, indicating that diethyl hypophosphorous acid was regenerated.

[0172] Comparative Example 5

[0173] Tetraethylenepentamine and diethyl hypophosphorous acid in a ratio of 1:5: 5 g (0.03 mol) of tetraethylenepentamine was mixed with 15.31 g (0.12) of diethyl hypophosphorous acid and heated to 100°C. A large amount of alkaline gas was detected in the tail gas using pH test paper, and pure TEPA-DEP-1-5 product could not be obtained.

[0174] Comparative Example 6

[0175] Heat 82.1 parts of epoxy resin DGEBA to 80°C. Once fully softened, add 17.9 parts of 4,4-diaminodiphenylmethane (DDM) and stir rapidly to dissolve the DDM. Once the DDM is completely dissolved, pour the hot mixture into a mold preheated at 80°C. Allow to stand for 10 minutes, then heat to 120°C for a pre-cure of 2 hours, and then heat to 170°C for a cure of 4 hours. Allow to cool naturally to room temperature to obtain pure EP material. The sample thickness is 3.2 mm. It meets the UL94NR rating and has a Tg of 149°C. Results are shown in Table 1.

[0176] Comparative Example 7

[0177] Heat 79.6 parts of epoxy resin DGEBA to 80°C. Once fully softened, add 17.4 parts of 4,4-diaminodiphenylmethane (DDM) and stir rapidly to dissolve the DDM. Once most of the DDM has dissolved, add 3 parts of melamine-DEP-1-3 (prepared in Comparative Example 2) and continue stirring for 1 minute to form a uniform mixture. While still hot, pour the mixture into a mold preheated at 80°C. Allow to stand for 10 minutes, then heat to 120°C for a pre-cure of 2 hours, then heat to 170°C for a cure of 4 hours. Allow to cool naturally to room temperature to obtain a 3 wt% EP / melamine-DEP-1-3 composite. The sample thickness is 3.2 mm. It meets the UL94V1 rating. Results are shown in Table 1.

[0178] Comparative Example 8

[0179] Heat 79.6 parts of epoxy resin DGEBA to 80°C. Once fully softened, add 17.4 parts of 4,4-diaminodiphenylmethane (DDM) and stir rapidly to dissolve the DDM. Once most of the DDM has dissolved, add 3 parts of DDM-DEP-1-2 (prepared in Comparative Example 1) and continue stirring for 1 minute to form a uniform mixture. While still hot, pour the mixture into a mold preheated at 80°C. Allow to stand for 10 minutes, then heat to 120°C for a pre-cure of 2 hours, then to 170°C for a cure of 4 hours. Allow to cool naturally to room temperature to obtain a 3wt% EP / DDM-DEP-1-2 composite. The sample thickness is 3.2mm. It meets the UL94 V0 rating and has a Tg of 153°C. Results are shown in Table 1.

[0180] Comparative Example 9

[0181] Mix 90.4 parts of F48 epoxy resin, 9.5 parts of dicyandiamide, and 0.1 parts of 2-methylimidazole. Add N,N-dimethylformamide (DMF) equal in mass to the dicyandiamide to promote dissolution. Heat at 100°C with stirring. Once a homogeneous solution is achieved, remove the DMF in a vacuum oven at 100°C. Finally, pour the mixture into a mold preheated at 100°C, pre-cure at 130°C for 1 hour, and cure at 170°C for 4 hours to obtain pure EP-F48. The specimen thickness is 3.2 mm. UL94NR rating is achieved. Results are shown in Table 1.

[0182] Comparative Example 10

[0183] After drying 100 parts of polypropylene (PP) in an 80°C forced air oven for 4 hours, the PP was melted in an internal mixer at 50 rpm and set to 200°C. After 6 minutes, the mixture was removed from the mixer, cooled, and dried. The PP was then filled into a mold, preheated for 10 minutes in a flat-plate vulcanizer at 200°C, maintained at 10 MPa for 5 minutes, and then cold-pressed. After cooling, samples were cut and tested. The sample thickness was 3.2 mm. UL94 NR rating.

[0184] Example 18 employed a flame retardant prepared using DDM as a raw material and used it as a reactive additive to partially replace the DDM curing agent. Soxhlet extraction of the cured sample revealed no traces of the flame retardant DDM-MDP-1-2 in the extract, demonstrating that DDM-MDP-1-2 can participate in epoxy resin curing and serve as a reactive flame retardant.

[0185] Comparative Example 7 and Examples 8 to 11 all used flame retardants prepared using melamine as a raw material, but the flame retardant efficiency of the reaction product of methyl diethylphosphinate and melamine was significantly higher than the flame retardant efficiency of the neutralization product of diethylphosphinic acid and melamine prepared in Comparative Example 2, even though the former had a lower phosphorus content, which was very unexpected.

[0186] Comparative Example 8 and Examples 16, 17, and 19 all use flame retardants prepared using DDM as raw material. The flame retardant efficiency of the flame retardant of the present application is comparable to the product of diethylphosphinic acid and DDM neutralized by Comparative Example 1, but the latter easily absorbs moisture and is inconvenient to store and use.

[0187] Examples 12-15, 22, and 23 demonstrate that the reaction products of diethylphosphinate with DICY and TEPA also exhibit very high flame retardancy. Example 14 achieves V0 with only 2 parts of the present flame retardant, and even with 1 part (Example 15), the epoxy resin significantly achieves V1. However, the corresponding neutralized product of diethylphosphinic acid cannot be obtained due to the acidolysis reaction of DICY and TEPA during the synthesis process (Comparative Examples 3, 4, and 5), demonstrating the superiority of diethylphosphinate over diethylphosphinic acid.

[0188] Comparison of Comparative Example 9 with Examples 24 and 25 demonstrates the excellent flame retardancy of the present invention's flame retardant in phenolic epoxy resins, with an addition level of less than 10% sufficient to meet flame retardancy requirements. Example 26 illustrates the application of the present invention's flame retardant in polypropylene (PP). This flame retardant, prepared using DICY as a raw material, can enable PP to pass the UL94 test at a 20% addition level. This demonstrates the wide application of the present invention's flame retardant in polymer materials such as epoxy resins and polyolefins.

[0189] Table 1 Application of dialkyl ammonium hypophosphite salt in epoxy resin

[0190] The applicant declares that while the above-mentioned examples are used to illustrate the dialkylphosphinate ammonium salts, their preparation methods, and applications, this application is not limited to these examples, nor does it imply that this application must rely on these examples for implementation. Persons skilled in the art should understand that any improvements to this application, equivalent substitutions for the raw materials used, addition of auxiliary components, and selection of specific methods, etc., fall within the scope of protection and disclosure of this application.

Claims

1. A dialkylphosphinate ammonium salt, the dialkylphosphinate ammonium salt being obtained by alkylating a dialkylphosphinate alkyl ester having a structural formula represented by formula (I) with NH3 or at least one nitrogen on a non-tertiary amine structure in an organic nitrogen-containing compound, the alkyl group participating in the alkylation reaction being derived from R1 in the structural formula represented by formula (I), the organic nitrogen-containing compound being selected from a primary amine, a secondary amine or an imine compound, and at least one nitrogen atom among the nitrogen atoms in the dialkylphosphinate ammonium salt that has undergone an alkylation reaction having an H atom and an R1 group obtained by the alkylation reaction at the same time; R1 is selected from C1~C 18 Straight chain alkyl, C1~C 18 Branched alkyl, or C3~C 18 Cycloalkyl; R2 and R3 are independently selected from C1 to C 18 Straight chain alkyl, C1~C 18 Branched alkyl, C3~C 18 Cycloalkyl or C6~C 24 Aromatic base.

2. The dialkylphosphinate ammonium salt according to claim 1, wherein R1 is selected from any one of methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl or decyl.

3. The dialkylphosphinate ammonium salt according to claim 1, wherein R2 and R3 are independently selected from any one of methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl or phenyl.

4. The dialkylphosphinate ammonium salt according to claim 1, wherein R1 is selected from any one of methyl, ethyl, propyl or butyl.

5. The dialkylphosphinate ammonium salt according to claim 1, wherein R1 is selected from any one of a methyl group and an ethyl group.

6. The dialkylphosphinate ammonium salt according to claim 1, wherein R2 and R3 are independently selected from any one of ethyl, propyl or butyl.

7. The dialkylphosphinate ammonium salt according to claim 1, wherein R2 and R3 are ethyl groups.

8. The dialkylphosphinate ammonium salt according to any one of claims 1 to 7, wherein The dihydrocarbyl phosphinate alkyl ester includes one or a combination of at least two of methyl dimethylphosphinate, methyl diethylphosphinate, methyl dipropylphosphinate, methyl ethylpropylphosphinate, methyl diphenylphosphinate, ethyl dimethylphosphinate, ethyl diethylphosphinate, ethyl dipropylphosphinate, ethyl ethylpropylphosphinate, propyl dimethylphosphinate, propyl diethylphosphinate, propyl dipropylphosphinate, propyl ethylpropylphosphinate, methylphenylphosphinate or methyl diphenylphosphinate; Optionally, the organic nitrogen-containing compound includes methylamine, ethylamine, propylamine, butylamine, pentylamine, hexylamine, heptylamine, octylamine, nonylamine, quinoline, dodecylamine, octadecylamine, cyclohexylamine, diethylamine, methylpropylamine, ethylenediamine, propylenediamine, butylenediamine, pentylenediamine, hexylenediamine, heptylenediamine, octylenediamine, 1,4-cyclohexyldiamine, diethanolamine, m-phenylenediamine, p-phenylenediamine, piperazine, 2-methylpiperazine, 2-methylimidazole, tetraethylenepentamine, triethylenetetramine, aniline, N-methylaniline, 4-methylaniline, diaminodiphenylmethane, 2,2-bis(4-aminophenyl)propane, diaminodiphenyl sulfone, diaminobenzophenone, cyanamide, melamine or One or a combination of at least two of dicyandiamides; Optionally, the imine has a structure shown in the following formula (II): Wherein, R4 and R5 are independently selected from hydrogen, substituted or unsubstituted alkyl, and substituted or unsubstituted aromatic. Optionally, the organic nitrogen-containing compound is a primary amine compound.

9. The dialkylphosphinate ammonium salt according to any one of claims 1 to 8, wherein The dialkyl ammonium hypophosphite salt has any one of the following structures: Wherein, R1, R2, and R3 are the same as defined in claim 1.

10. The method for preparing the dialkylphosphinate ammonium salt according to any one of claims 1 to 9, comprising the following steps: Alkylation of dihydrocarbylphosphinate alkyl ester with NH3 or at least one nitrogen on a non-tertiary amine structure in an organic nitrogen-containing compound Reaction to obtain the dialkylphosphinate ammonium salt.

11. The preparation method according to claim 10, wherein: The dihydrocarbyl phosphinate alkyl ester includes any one or a combination of two of dimethyl phosphinate, diethyl phosphinate, dipropyl phosphinate, ethyl propyl phosphinate, diphenyl phosphinate, ethyl dimethyl phosphinate, ethyl diethyl phosphinate, dipropyl phosphinate, ethyl propyl phosphinate, propyl dimethyl phosphinate, propyl diethyl phosphinate, propyl dipropyl phosphinate, propyl ethyl propyl phosphinate, methyl phenyl phosphinate or diphenyl phosphinate; Optionally, the organic nitrogen-containing compound includes any one or a combination of two of methylamine, ethylamine, propylamine, butylamine, pentylamine, hexylamine, heptylamine, octylamine, nonylamine, quinoline, dodecylamine, octadecylamine, cyclohexylamine, diethylamine, methylpropylamine, ethylenediamine, propylenediamine, butylenediamine, pentylenediamine, hexylenediamine, heptylenediamine, octanediamine, 1,4-cyclohexyldiamine, diethanolamine, m-phenylenediamine, p-phenylenediamine, piperazine, 2-methylpiperazine, 2-methylimidazole, tetraethylenepentamine, triethylenetetramine, aniline, N-methylaniline, 4-methylaniline, diaminodiphenylmethane, 2,2-bis(4-aminophenyl)propane, diaminodiphenyl sulfone, diaminobenzophenone, cyanamide, melamine or dicyandiamide.

12. The preparation method according to claim 10 or 11, wherein: The molar ratio of the sum of the moles of nitrogen in the organic nitrogen-containing compound to the dihydrocarbyl phosphinate alkyl ester is 10 / 1-1 / 10; Optionally, the alkylation reaction temperature is 0-250°C; Optionally, the alkylation reaction time is 0.1-30 hours.

13. A flame retardant polymer material, comprising a flame retardant and a polymer material, wherein the flame retardant comprises the dialkylphosphinate ammonium salt according to any one of claims 1 to 9.

14. The flame retardant polymer material according to claim 13, wherein: The flame retardant polymer material comprises 0.1-50wt% of a flame retardant and 50-99.9wt% of a polymer material; Optionally, the flame retardant polymer material further includes a functional additive; Optionally, the functional additive is selected from at least one of a reinforcing agent, an anti-dripping agent, a stabilizer, a pigment, a dye, a carbon-forming catalyst, a dispersant, a nucleating agent, an inorganic filler, an organic filler or an antioxidant; Optionally, the reinforcing agent is selected from glass fiber; Optionally, the anti-dripping agent is selected from Teflon; Optionally, the inorganic filler is selected from at least one of silicon dioxide, mica, calcium carbonate, aluminum oxide, aluminum nitride, talc, calcium oxide, calcium silicate, glass fiber powder or silica; Optionally, the organic filler is selected from at least one of polytetrafluoroethylene powder, polyphenylene sulfide powder or polyethersulfone powder; Optionally, the mass content of the functional additive in the flame retardant polymer material is 5-40%; Optionally, the flame retardant polymer material further includes a flame retardant Q; Optionally, the flame retardant Q is selected from at least one of a phosphorus flame retardant, a nitrogen flame retardant or a boron flame retardant; Optionally, the phosphorus-based flame retardant is selected from at least one of bisphosphates, phosphazenes, dialkyl phosphinates, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide derivatives, 6,6'-(1,2-ethanediyl)bis-6,6'-dioxide, HTP-6123, and phosphine oxide compounds; Optionally, the bisphosphate is selected from at least one of bisphenol A bisdiphenyl phosphate, resorcinol bisdiphenyl phosphate or 1,3-phenylene (2,6-xylyl) tetraphosphate; Optionally, the phosphazene flame retardant is selected from at least one of hexaphenoxy cyclotriphosphazene, cyanophenoxyphosphazene, allyl cyclophosphazene or cyclic biphenyloxyphosphazene; Optionally, the dihydrocarbyl phosphinate is selected from at least one of aluminum diethylphosphinate, aluminum diisobutylphosphinate, aluminum dipropylphosphinate, and zinc diethylphosphinate; Optionally, the 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide derivative is selected from at least one of 6H-dibenzo[c,e][1,2]oxaphosphatinane-6,6'-(1,4-ethanediyl)bis-6,6'-dioxide and 6H-dibenzo[c,e][1,2]oxaphosphatinane-6,6'-(1,4-phenylethanediyl)bis-6,6'-dioxide; Optionally, the phosphine oxide compound is p-xylylbisdiphenylphosphine oxide; Optionally, the nitrogen-based flame retardant is selected from at least one of melamine cyanurate, melamine polyphosphate or ammonium polyphosphate; Optionally, the boron flame retardant is selected from zinc borate; Optionally, the mass content of the flame retardant Q in the flame retardant polymer material is 0.5-20%; Optionally, the polymer material is selected from thermoplastic polymer resin or thermosetting resin; Optionally, the thermoplastic polymer resin is selected from at least one of polybutadiene, polyamide, polyester, polyphenylene ether, acrylonitrile-butadiene-styrene copolymer, polyethylene, polypropylene, polyvinyl chloride, polystyrene, polyimide, polyphenylene sulfide or polyetheretherketone; Optionally, the thermosetting resin is selected from at least one of vinyl polyphenylene ether resin, epoxy resin, cyanate resin, BT resin, bismaleimide resin, phenolic resin, polyurethane resin, thermosetting polyimide, unsaturated polyester resin, vinyl resin, benzoxazine resin, arylacetylene resin or furan resin; Optionally, the thermosetting resin is at least one of vinyl polyphenylene ether resin, epoxy resin, cyanate resin, BT resin, bismaleimide resin, and thermosetting polyimide; Optionally, the thermosetting resin is an epoxy resin; Optionally, the epoxy resin is selected from at least one of bisphenol A epoxy resin, bisphenol F epoxy resin, dicyclopentadiene epoxy resin, biphenyl epoxy resin or naphthol epoxy resin.

15. The flame retardant polymer material according to claim 13 or 14, wherein: The flame retardant polymer material is a flame retardant epoxy resin material, the flame retardant epoxy resin material comprises a flame retardant and an epoxy resin, and the flame retardant comprises a dialkyl phosphinate ammonium salt as described in any one of claims 1 to 9; Optionally, the flame retardant epoxy resin material comprises 0.1-18 wt % of dialkylphosphinate ammonium salt and 82-99.9 wt % of epoxy resin.

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