P-c bond-containing phosphorus-nitrogen triazine flame retardant and preparation method thereof

Abstract

The application discloses a phosphorus-nitrogen triazine flame retardant containing P-C bonds and a preparation method, wherein a typical Schiff base synthesis reaction occurs between amino groups in 2,4,6-tris(4-aminophenyl)-1,3,5-triazine and aldehyde groups in furfural, and then a nucleophilic substitution reaction occurs between P-H bonds and C=N bonds; the preparation process is simple, the reaction condition is mild, and the yield is high; in the preparation process, the intermediate does not need to be separated and purified, no toxic and harmful gas substances are generated, the use of traditional acid-binding agents such as triethylamine or pyridine is avoided, the flame retardant effectively prevents great harm caused by irritating odors to the human body and the environment, and the phosphorus-nitrogen triazine flame retardant containing P-C bonds belongs to an intumescent flame retardant, and the flame-retardant effect is remarkable.

Description

Technical Field

[0001] This invention relates to the field of organic synthetic fire retardant technology, specifically to a phosphorus-nitrogen triazine flame retardant containing PC bonds and its preparation method. Background Technology

[0002] Epoxy resin (EP) possesses excellent chemical resistance, dimensional stability, adhesion, electrical insulation, and low manufacturing cost, making it widely used in aerospace, laminates, coatings, adhesives, and encapsulation. However, its high hydrocarbon content results in poor flame retardancy, susceptibility to tempering, and the production of large amounts of dense smoke and toxic gases upon combustion, severely limiting its application in many fields. Therefore, researching and improving the fire safety of EP is particularly important, and adding flame retardants is one of the most effective methods.

[0003] In fire-retardant materials across various industries, substances containing phosphorus (P) or nitrogen (N) play a crucial role in flame retardancy. Diphenylphosphine oxide (DPO), 9,10-dihydro-9-oxa-10-phosphenanthrene-10-oxide (DOPO), and diphenyl phosphite (DPP), all containing P, are highly active quenching agents with low corrosivity, and can participate in many synthetic reactions as acid sources. Some compounds containing triazine units possess excellent charring capabilities due to their abundant nitrogen content and high-temperature resistant triazine rings, and have low water solubility, making them suitable as charring agents and foaming agents to provide a robust, physically dense layer for polymers (EP). However, simply adding P-containing DPO, DOPO, DPP, or N-containing triazine compounds to polymers to achieve flame retardancy has the major drawback of high loading, leading to a significant decrease in the polymer's mechanical and flame-retardant properties. Therefore, it is necessary to integrate and modify these compounds to diversify the functions of phosphorus and nitrogen elements. In the fire protection industry, the formation reaction of polyphosphate (PC) bonds plays a vital role in flame retardancy.

[0004] Electrophilic addition reactions involving PH bonds and triazine functional groups provide novel phosphorus and nitrogen sources for constructing PC bonds, representing one of the more novel synthetic routes for flame retardants. Previous reports have mostly focused on nucleophilic substitution reactions involving PN bonds. In recent years, many research groups have investigated methods for synthesizing phosphorus-nitrogen triazine flame retardants involving PC bonds. WO 2020 / 228021Al reported a method for preparing a phosphorus-nitrogen flame retardant containing DOPO-modified hexamethyl melamine; however, this method requires strong acid catalysts and high-temperature melting reaction conditions, increasing process costs. Therefore, developing a novel, environmentally friendly flame retardant that is simple to prepare, inexpensive, and highly efficient is of great significance in addressing the issues of flame resistance and smoke suppression, as well as some drawbacks of traditional flame retardants. Summary of the Invention

[0005] The purpose of this invention is to provide a phosphorus-nitrogen triazine flame retardant containing PC bonds and its preparation method. This method does not require the use of any catalysts or additives and can be completed through a simple three-step reaction. It is suitable for large-scale production and can be used in nucleophilic addition reactions containing PH bonds and C=N bonds. The reaction conditions are mild, the reaction time is short, and the cost is low.

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

[0007] A phosphorus-nitrogen triazine flame retardant containing PC bonds, the structure of which is as follows:

[0008]

[0009] Wherein, R1 and R2 are phenyl, methyl, n-propyl, isopropyl, (E)-3-phenylprop-1-en-1-amino-substituted phenyl, phenoxy, ethyltrimethylsilyl-substituted phenoxy, heteroaryl, heterocyclic, or fused cycloalkylaryl with an oxygen atom; R3 is 2-furanyl, phenyl, 4-ethylphenyl, 4-propylfuran-2-yl, or 2-naphthyl.

[0010] Furthermore, the heteroaryl group is a phenoxy group in which the C at position 1 is substituted by an N atom.

[0011] Furthermore, the heterocyclic group is a dihexacyclic nonaromatic compound in which the C at position 2 is replaced by an N atom.

[0012] Furthermore, the fused cycloalkylaryl group formed with the oxygen atom is a group containing a biphenyl structure formed by the phenyl group and the phenoxy group.

[0013] Furthermore, the flame retardant structure is one of the following structural formulas:

[0014]

[0015]

[0016] A method for preparing a phosphorus-nitrogen triazine flame retardant containing PC bonds includes the following steps:

[0017] (1) 2,4,6-tris(4-aminophenyl)-1,3,5-triazine was added to 1,4-dioxane, dissolved, and then furfural or furfural analogs were added. The mixture was stirred at 30-80°C to obtain 1-(furan-2-yl)-N-(4-(4-(4-(((E)-furan-2-ylmethylene)amino)phenyl)-6-(4-(((Z)-furan)-2-ylmethylene)amino)phenyl)-1,3,5-triazin-2-yl)phenyl)methylimine or 1-(furan-2-yl)-N-(4-(4-((((E)-furan-2-ylmethylene)amino)phenyl)-6-(4-(((Z)-furan)-2-ylmethylene)amino)phenyl)-1,3,5-triazin-2-yl)phenyl)methylimine analogs;

[0018] (2) Add 1-(furan-2-yl)-N-(4-(4-(4-(((E)-furan-2-ylmethylene)amino)phenyl)-6-(4-(((Z)-furan)-2-ylmethylene)amino)phenyl)-1,3,5-triazin-2-yl)phenyl)methylimine or an analogue of 1-(furan-2-yl)-N-(4-(4-(4-(((E)-furan-2-ylmethylene)amino)phenyl)-6-(4-(((Z)-furan)-2-ylmethylene)amino)phenyl)-1,3,5-triazin-2-yl)phenyl)methylimine to acetonitrile, dissolve, add DPO or a DPO analogue, and stir at 30-80°C to obtain a phosphorus-nitrogen triazine flame retardant containing PC bonds.

[0019] Furthermore, the ratio of 2,4,6-tris(4-aminophenyl)-1,3,5-triazine, 1,4-dioxane to furfural is 14.17–17.71 g: 90–100 mL: 11.52–19.20 g;

[0020] The ratio of 2,4,6-tris(4-aminophenyl)-1,3,5-triazine, 1,4-dioxane to furfural analogue is 14.17–17.71 g: 90–100 mL: 12.72–18.73 g.

[0021] Furthermore, the structural formula of the DPO analogue is as follows:

[0022]

[0023] Wherein, R1 and R2 are phenyl, methyl, n-propyl, isopropyl, (E)-3-phenylprop-1-en-1-amino-substituted phenyl, phenoxy, ethyltrimethylsilyl-substituted phenoxy, heteroaryl, heterocyclic, or fused cycloalkylaryl with oxygen atoms.

[0024] Furthermore, the heteroaryl group is a phenoxy group in which the C at position 1 is substituted by an N atom;

[0025] The heterocyclic group is a dihexacyclic nonaromatic compound in which the C at position 2 is replaced by an N atom.

[0026] The fused cycloalkylaryl group formed with oxygen atoms is a group containing a biphenyl structure formed by the phenyl group and the phenoxy group.

[0027] Furthermore, the ratio of 1-(furan-2-yl)-N-(4-(4-(4-(((E)-furan-2-ylmethylene)amino)phenyl)-6-(4-(((Z)-furan)-2-ylmethylene)amino)phenyl)-1,3,5-triazin-2-yl)phenyl)methylimine, acetonitrile, and DPO is 23.53–29.41 g: 90–100 mL: 24.26–32.35 g;

[0028] The ratio of 1-(furan-2-yl)-N-(4-(4-(4-(((E)-furan-2-ylmethylene)amino)phenyl)-6-(4-(((Z)-furan)-2-ylmethylene)amino)phenyl)-1,3,5-triazin-2-yl)phenyl)methylimine analog, acetonitrile, and DPO is 24.73–30.73 g: 90–100 mL: 24.26–32.35 g;

[0029] The ratio of 1-(furan-2-yl)-N-(4-(4-(4-(((E)-furan-2-ylmethylene)amino)phenyl)-6-(4-(((Z)-furan)-2-ylmethylene)amino)phenyl)-1,3,5-triazin-2-yl)phenyl)methylimine, acetonitrile, and DPO analog is 23.53–26.66 g : 90–100 mL : 25.94–52.10 g;

[0030] The ratio of 1-(furan-2-yl)-N-(4-(4-(4-(((E)-furan-2-ylmethylene)amino)phenyl)-6-(4-(((Z)-furan)-2-ylmethylene)amino)phenyl)-1,3,5-triazin-2-yl)phenyl)methylimine analog, acetonitrile, and DPO analog is 24.73–30.73 g: 90–100 mL: 25.94–52.10 g.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] The raw materials used in this invention, DPO, DOPO, and DPP, are inexpensive. The resulting phosphorus-nitrogen triazine flame retardant containing PC bonds is an organic macromolecular compound with good compatibility with epoxy resins and will not leach out of the matrix. The reaction principle involves a typical Schiff base synthesis reaction between the amino group in 2,4,6-tris(4-aminophenyl)-1,3,5-triazine (TAPT) and the aldehyde group in furfural, followed by a nucleophilic substitution reaction between the PH bond and the C=N bond. The preparation process is simple, the reaction conditions are mild, and the yield is high. During the preparation process, intermediates do not require separation and purification, and no toxic or harmful gaseous substances are generated, avoiding the use of traditional acid-binding agents such as triethylamine or pyridine. This flame retardant effectively prevents the great harm caused to human health and the environment by irritating odors.

[0033] The phosphorus-nitrogen triazine flame retardant containing PC bonds of the present invention is an intumescent flame retardant with significant flame retardant effect. Only 10 wt.% of the flame retardant is needed to achieve the UL-94V-0 rating. It also has excellent compatibility with epoxy resin, does not bleed into the matrix, and has good low smoke and low toxicity properties. This flame retardant is green and environmentally friendly, and has low smoke and low toxicity properties. Furthermore, the phosphorus-nitrogen triazine flame retardant containing PC bonds can undergo a PN synergistic flame retardant effect when heated, which can generate non-toxic oxygen barrier gas and a uniform and dense char layer, effectively preventing the spread and propagation of flames. Attached Figure Description

[0034] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0035] Figure 1 This is the FT-IR spectrum of PFPM in Embodiment 2 of the present invention.

[0036] Figure 2 This is the FT-IR spectrum of TTFDO in Embodiment 7 of the present invention.

[0037] Figure 3 The image shows the FT-IR spectrum of the TTFTO in Embodiment 13 of the present invention.

[0038] Figure 4 The image shows the FT-IR spectrum of DFPTP in Embodiment 16 of the present invention. Detailed Implementation

[0039] To enhance understanding of the present invention, the present invention will be further described below with reference to embodiments. These embodiments are only used to explain the present invention and do not constitute a limitation on the scope of protection of the present invention.

[0040] The instruments and reagents used in this invention: Fourier transform infrared spectroscopy (FTIR) was performed using a Frontier-PerkinElmer Fourier transform infrared spectrometer manufactured by PerkinElmer, USA. Other instruments were standard laboratory equipment: FA2004 electronic balance, 101-1A electric heating drying oven, and CL-2A digital display magnetic stirrer. All reagents used were of analytical grade.

[0041] The present invention discloses a phosphorus-nitrogen triazine flame retardant containing PC bonds, the structure of which is shown below:

[0042]

[0043] in,

[0044] R1 and R2 can be phenyl, methyl, n-propyl, isopropyl, or (E)-3-phenylprop-1-en-1-amino-substituted phenyl groups; or

[0045] R1 and R2 can be phenoxy or ethyltrimethylsilyl-substituted phenoxy groups; or R1 and R2 can be heteroaryl or heterocyclic groups, or form fused cycloalkylaryl groups with oxygen atoms.

[0046] The heteroaryl group is a phenoxy group in which the C at the 1-position is replaced by an N atom.

[0047] The heterocyclic group is a dihexacyclic nonaromatic compound in which the C at position 2 is replaced by an N atom.

[0048] The fused cycloalkylaryl group formed with oxygen atoms is a group containing a biphenyl structure formed by the phenyl group and the phenoxy group.

[0049] R3 can be 2-furanyl, phenyl, 4-ethylphenyl, 4-propylfuran-2-yl, or 2-naphthyl.

[0050] For example, the flame retardant includes, but is not limited to, the following structures:

[0051]

[0052]

[0053] A method for preparing a phosphorus-nitrogen triazine flame retardant containing PC bonds includes the following steps:

[0054] (1) After drying 2,4,6-tris(4-aminophenyl)-1,3,5-triazine (TAPT), add it to 1,4-dioxane in air until dissolved, and then add furfural or furfural analogue. Magnetic stirring for 20–24 h, with the temperature controlled at 30–80 °C, yields 1-(furan-2-yl)-N-(4-(4-(4-(((E)-furan-2-ylmethylene)amino)phenyl)-6-(4-(((Z)-furan)-2-ylmethylene)amino)phenyl)-1,3,5-triazin-2-yl)phenyl)methylimine (PFPM) or PFPM analogues.

[0055] The dosage ratio of TAPT, 1,4-dioxane to furfural is 14.17–17.71 g: 90–100 mL: 11.52–19.20 g.

[0056] The dosage ratio of TAPT, 1,4-dioxane to furfural analogue is 14.17–17.71 g: 90–100 mL: 12.72–18.73 g.

[0057] (2) After drying the product 1-(furan-2-yl)-N-(4-(4-(4-((((E)-furan-2-ylmethylene)amino)phenyl)-6-(4-((((Z)-furan)-2-ylmethylene)amino)phenyl)-1,3,5-triazin-2-yl)phenyl)methylimine (PFPM) or a PFPM analogue, add it to acetonitrile in an air atmosphere until dissolved, and then add DPO (diphenylphosphine oxide containing phosphorus) or a similar substance. The mixture was magnetically stirred for 20–24 hours at a temperature controlled between 30 and 80°C to obtain a phosphorus-nitrogen triazine flame retardant TTFDO or a TTFDO analog containing PC bonds.

[0058] The ratio of PFPM, acetonitrile and DPO is 23.53-29.41g: 90-100mL: 24.26-32.35g.

[0059] The ratio of PFPM analog, acetonitrile and DPO is 24.73-30.73 g: 90-100 mL: 24.26-32.35 g.

[0060] The ratio of PFPM, acetonitrile and DPO analog is 23.53–26.66 g: 90–100 mL: 25.94–52.10 g.

[0061] The ratio of PFPM analog, acetonitrile and DPO analog is 24.73-30.73 g: 90-100 mL: 25.94-52.10 g.

[0062] The application of the PC-bonded phosphorus-nitrogen triazine flame retardant in epoxy resin, as described above, is specifically as follows: Epoxy resin and TTFDO (TTFDO's Chinese name is (1,3,5-triazine-2,4,6-triacyl)tris(phenyl-4,1-diacyl)tris(azadiacyl)tris(furan-2-methylene)tris(diphenylphosphine oxide)) or a TTFDO analogue are added to a container, stirred evenly, and stirred at 160-170°C in an air atmosphere for 0.5-1 hour until homogeneous. Then, the curing agent sulfamic acid sulfone (DDS) is added, and stirred for 5-10 minutes until homogeneous. The mixture is then poured into a pre-prepared polytetrafluoroethylene (PTFE) mold and cured in an oven at 120°C, 150°C, and 180°C for two consecutive hours to obtain the cured epoxy resin.

[0063] Furthermore, the mass ratio of epoxy resin, TTFDO and DDS is 120-130g: 17.8-19.4g: 40-45g.

[0064] Furthermore, the mass ratio of epoxy resin, TTFDO analog to DDS is 120–130 g: 17.8–19.4 g: 40–45 g.

[0065] In this invention, room temperature refers to a temperature of 30°C.

[0066] Example 1: Preparation of PFPM

[0067] 14.17 g of TAPT, 90 mL of 1,4-dioxane, and 11.52 g of furfural were added to a 500 mL three-necked flask equipped with a magnetic stirrer. The mixture was reacted at 30 °C for 24 h. After the reaction was complete, the mixture was washed three times with deionized water, filtered, and dried at 60 °C for 24 h to remove the solvent, yielding a green product with a yield of 61%.

[0068] The reaction equation is as follows:

[0069]

[0070] Example 2: Preparation of PFPM

[0071] 14.17 g of TAPT, 95 mL of 1,4-dioxane, and 11.52 g of furfural were added to a 500 mL three-necked flask equipped with a magnetic stirrer. The mixture was reacted in an oil bath at 60 °C for 24 h. After the reaction was complete, the mixture was washed three times with deionized water, filtered, and dried at 60 °C for 24 h to remove the solvent, yielding a green product with a yield of 88%.

[0072] The reaction equation is as follows:

[0073]

[0074] Example 3: Preparation of PFPM

[0075] 14.17 g of TAPT, 92 mL of 1,4-dioxane, and 11.52 g of furfural were added to a 500 mL three-necked flask equipped with a magnetic stirrer. The mixture was reacted in an oil bath at 80 °C for 24 h. After the reaction was complete, the mixture was washed three times with deionized water, filtered, and dried at 60 °C for 24 h to remove the solvent, yielding a green product with a yield of 70%.

[0076] The reaction equation is as follows:

[0077]

[0078] Example 4: Preparation of PFPM

[0079] 14.84 g of TAPT, 97 mL of 1,4-dioxane, and 12.48 g of furfural were added to a 500 mL three-necked flask equipped with a magnetic stirrer. The mixture was reacted in an oil bath at 60 °C for 24 h. After the reaction was complete, the mixture was washed three times with deionized water, filtered, and dried at 60 °C for 24 h to remove the solvent, yielding a green product with a yield of 81%.

[0080] The reaction equation is as follows:

[0081]

[0082] Example 5: Preparation of PFPM

[0083] 15.94 g of TAPT, 100 mL of 1,4-dioxane, and 14.39 g of furfural were added to a 500 mL three-necked flask equipped with a magnetic stirrer. The mixture was reacted in an oil bath at 60 °C for 24 h. After the reaction was complete, the mixture was washed three times with deionized water, filtered, and dried at 60 °C for 24 h to remove the solvent, yielding a green product with a yield of 82%.

[0084] The reaction equation is as follows:

[0085]

[0086] Example 6: Preparation of PFPM

[0087] 17.71 g of TAPT, 100 mL of 1,4-dioxane, and 19.20 g of furfural were added to a 500 mL three-necked flask equipped with a magnetic stirrer. The mixture was reacted in an oil bath at 60 °C for 24 h. After the reaction was complete, the mixture was washed three times with deionized water, filtered, and dried at 60 °C for 24 h to remove the solvent, yielding a green product with a yield of 79%.

[0088] The reaction equation is as follows:

[0089]

[0090] Example 7: Preparation of flame retardant TTFDO

[0091] 23.53 g of PFPM (prepared in Example 2) and 90 mL of acetonitrile were added to a 500 mL three-necked flask equipped with a magnetic stirrer, followed by 24.26 g of DPO. The mixture was reacted at room temperature for 24 h. After the reaction was complete, the mixture was washed three times with deionized water, filtered, and dried at 60 °C for 24 h to remove the solvent, yielding a yellow-green product with a yield of 77%.

[0092] The reaction equation is as follows:

[0093]

[0094] Example 8: Preparation of flame retardant TTFDO

[0095] 23.53 g of PFPM (prepared in Example 2), 95 mL of acetonitrile, and 24.26 g of DPO were added to a 500 mL three-necked flask equipped with a magnetic stirrer. The mixture was reacted in an oil bath at 60 °C for 24 h. After the reaction was complete, the mixture was washed three times with deionized water, filtered, and dried at 60 °C for 24 h to remove the solvent, yielding a yellow-green product with a yield of 75%.

[0096] The reaction equation is as follows:

[0097]

[0098] Example 9: Preparation of flame retardant TTFDO

[0099] In a 500 mL three-necked flask equipped with a magnetic stirrer, 23.53 g of PFPM (prepared in Example 2), 100 mL of acetonitrile, and then 24.26 g of DPO were added. The mixture was reacted in an oil bath at 80 °C for 24 h. After the reaction was complete, the mixture was washed three times with deionized water, filtered, and dried at 60 °C for 24 h to remove the solvent, yielding a yellow-green product with a yield of 71%.

[0100] The reaction equation is as follows:

[0101]

[0102] Example 10: Preparation of flame retardant TTFDO

[0103] 25.29 g of PFPM (prepared in Example 2), 100 mL of acetonitrile, and 27.30 g of DPO were added to a 500 mL three-necked flask equipped with a magnetic stirrer. The mixture was reacted at room temperature for 24 h. After the reaction was complete, the product was washed three times with deionized water, filtered, and dried at 60 °C for 24 h to remove the solvent, yielding a yellow-green product with a yield of 74%.

[0104] The reaction equation is as follows:

[0105]

[0106] Example 11: Preparation of flame retardant TTFDO

[0107] 26.47 g of PFPM (obtained in Example 2), 100 mL of acetonitrile, and 28.31 g of DPO were added to a 500 mL three-necked flask equipped with a magnetic stirrer. The mixture was reacted at room temperature for 24 h. After the reaction was complete, the product was washed three times with deionized water, filtered, and dried at 60 °C for 24 h to remove the solvent, yielding a yellow-green product with a yield of 75%.

[0108] The reaction equation is as follows:

[0109]

[0110] Example 12: Preparation of flame retardant TTFDO

[0111] 29.41 g of PFPM (prepared in Example 2), 100 mL of acetonitrile, and 32.35 g of DPO were added to a 500 mL three-necked flask equipped with a magnetic stirrer. The mixture was reacted at room temperature for 24 h. After the reaction was complete, the product was washed three times with deionized water, filtered, and dried at 60 °C for 24 h to remove the solvent, yielding a yellow-green product with a yield of 70%.

[0112] The reaction equation is as follows:

[0113]

[0114] Example 13: Preparation of flame retardant TTFTO

[0115] In a 500 mL three-necked flask equipped with a magnetic stirrer, 23.53 g of PFPM (prepared in Example 2), 100 mL of acetonitrile, and then 25.94 g of DOPO were added. The mixture was reacted at room temperature for 24 h. After the reaction was complete, the mixture was washed three times with deionized water, filtered, and dried at 60 °C for 24 h to remove the solvent, yielding an orange-yellow product 6,6′,6″-((((1,3,5-triazine-2,4,6-triyl)tris(phenyl-4,1-diyl))tris(azadiyl))tris(furan-2-methylene))tris(dibenzo[c,e][1,2]oxaphosphine 6-oxide) (TTFTO) in 73% yield.

[0116] The reaction equation is as follows:

[0117]

[0118] Example 14: Preparation of flame retardant TTFTO

[0119] 23.53 g of PFPM (prepared in Example 2), 100 mL of acetonitrile, and 25.94 g of DOPO were added to a 500 mL three-necked flask equipped with a magnetic stirrer. The mixture was reacted at 60 °C for 24 h. After the reaction was complete, the mixture was washed three times with deionized water, filtered, and dried at 60 °C for 24 h to remove the solvent, yielding an orange-yellow product with a yield of 60%.

[0120] The reaction equation is as follows:

[0121]

[0122] Example 15: Preparation of flame retardant TTFTO

[0123] 24.79 g of PFPM (prepared in Example 2), 100 mL of acetonitrile, and 30.34 g of DOPO were added to a 500 mL three-necked flask equipped with a magnetic stirrer, and the mixture was reacted at room temperature for 24 h. After the reaction was complete, the mixture was washed three times with deionized water, filtered, and dried at 60 °C for 24 h to remove the solvent, yielding an orange-yellow product with a yield of 70%.

[0124] The reaction equation is as follows:

[0125]

[0126] Example 16: Preparation of flame retardant DFPTP

[0127] 23.53 g of PFPM (prepared in Example 2) and 100 mL of acetonitrile were added to a 500 mL three-necked flask equipped with a magnetic stirrer, followed by 28.10 g of DPP. The mixture was reacted at room temperature for 24 h. After the reaction was complete, the mixture was washed three times with deionized water, filtered, and dried at 60 °C for 24 h to remove the solvent, yielding a dark blue product, diphenyl((1S)-((4-(4-(((((R)-(diphenoxyphosphoryl)(furan-2-yl)methyl)amino)phenyl)-6-(4-([diphenoxyphosphoryl](furan-2-yl)methyl ester)amino)phenyl)-1,3,5-triazin-2-ylphenyl)amino)(furan-2-methyl)phosphonate (DFPTP), in 65% yield.

[0128] The reaction equation is as follows:

[0129]

[0130] Example 17: Preparation of flame retardant DFPTP

[0131] 23.53 g of PFPM (prepared in Example 2), 100 mL of acetonitrile, and 28.10 g of DPP were added to a 500 mL three-necked flask equipped with a magnetic stirrer. The mixture was reacted at 60 °C for 24 h. After the reaction was complete, the product was washed three times with deionized water, filtered, and dried at 60 °C for 24 h to remove the solvent, yielding a dark blue product with a yield of 60%.

[0132] The reaction equation is as follows:

[0133]

[0134] Example 18: Preparation of flame retardant DFPTP

[0135] 26.66 g of PFPM (prepared in Example 2), 100 mL of acetonitrile, and 35.08 g of DPP were added to a 500 mL three-necked flask equipped with a magnetic stirrer, and the mixture was reacted at room temperature for 24 h. After the reaction was complete, the product was washed three times with deionized water, filtered, and dried at 60 °C for 24 h to remove the solvent, yielding a dark blue product with a yield of 62%.

[0136] The reaction equation is as follows:

[0137]

[0138] Example 19: Preparation of Flame Retardant

[0139] Using PFPM (prepared in Example 2) and bis(4-isopropylphenyl)phosphine oxide as raw materials, in amounts of 23.53 g and 34.34 g respectively, a solvent method was used to synthesize (1,3,5-triazine-2,4,6-triacyl)tris(phenyl-4,1-diacyl)tris(azadiacyl)tris(furan-2-methylene)tris(bis(4-isopropylphenyl)phosphine oxide) at room temperature for 24 h, with a yield of 63%. The structural formula of the product is as follows:

[0140]

[0141] Example 20: Preparation of Flame Retardant

[0142] Using TAPT and 4-propylfuran-2-carboxaldehyde as raw materials, in amounts of 23.53 g and 16.57 g respectively, and with 1,4-dioxane (100 mL) as solvent, the reaction was carried out at 60 °C for 24 h to obtain (1Z,1'Z)-N,N'-((6-(4-((((E)-(4-propylfuran-2-yl)methylene)amino)phenyl)-1,3,5-triazine-2,4-diyl)bis(4,1-phenylene)). Bis(1-(4-propylfuran-2-yl)methylimine), reacted with bis(4-propylphenyl)phosphine oxide in amounts of 28.57 g and 34.33 g, respectively, using acetonitrile (100 mL) as solvent, and reacted at room temperature for 24 h to synthesize (1,3,5-triazine-2,4,6-triyl)tris(phenyl-4,1-diyl))tris(azadiyl)trimethylene)tris(bis(4-propylphenyl)phosphine oxide), with a yield of 60%. The structural formula of the product is as follows:

[0143]

[0144] Example 21: Preparation of flame retardant

[0145] Using TAPT and benzaldehyde as raw materials, with amounts of 23.53 g and 12.72 g respectively, and 1,4-dioxane (100 mL) as solvent, the reaction was carried out at 60 °C for 24 h to obtain (1Z,1'Z,1”Z)-N,N',N'-((1,3,5-triazine-2,4,6-triyl)tri(phenyl-4,1-diyl))tri(1-phenylmethaneamine), which reacts with bis(4-((E)-3-aminoallyl) Phosphine oxide was further reacted with 24.73 g and 37.48 g of acetonitrile (100 mL) as solvent at room temperature for 24 h to synthesize (1,3,5-triazine-2,4,6-triacyl)tris(phenyl-4,1-diacyl)tris(azadiacyl)tris(phenylmethylene)tris(bis(4-((E)-3-aminoallyl)phenyl)phosphine oxide), with a yield of 59%. The structural formula of the product is as follows:

[0146]

[0147] Example 22: Preparation of flame retardant

[0148] Using TAPT and 4-ethylbenzaldehyde as raw materials, in amounts of 23.53 g and 16.09 g respectively, and with 1,4-dioxane (100 mL) as solvent, the reaction was carried out at 60 °C for 24 h to obtain (1Z,1'Z,1”Z)-N,N',N'-((1,3,5-triazine-2,4,6-triyl)tris(phenyl-4,1-diyl))tris(1-(4-ethylphenyl)methane). This was further reacted with bis(pyridin-4-yl)phosphonate, in amounts of 28.17 g and 28.32 g respectively, with acetonitrile (… The reaction was carried out at room temperature for 24 h using 100 mL of solvent to synthesize bis(pyridin-4-yl)((1S)-((4-(4-((((R))-(bis(pyridin-4-yloxy)phosphoryl)(4-ethylphenyl)methyl)amino)phenyl))-6-(4-(((bis(pyridin-4-yloxy)phosphoryl)(4-ethylphenyl)methyl)amino)phenyl)-1,3,5-triazin-2-yl)phenyl)amino)(4-ethylphenyl)methyl)phosphonate in 55% yield. The structural formula of the product is as follows:

[0149]

[0150] Example 23: Preparation of flame retardant

[0151] Using TAPT and 2-naphthaldehyde as raw materials, in amounts of 23.53 g and 18.73 g respectively, and with 1,4-dioxane (100 mL) as solvent, the reaction was carried out at 60 °C for 24 h to obtain (1Z,1'Z,1”Z)-N,N',N'-((1,3,5-triazine-2,4,6-triyl)tris(phenyl-4,1-diyl))tris(1-(naphth-2-yl)methane). This was further reacted with di-p-tolylphosphine oxide in amounts of 30.7 g and 18.73 g respectively. 3 g and 27.61 g of bis(4,1-phenylene))bis(azadiyl))bis(furan-2-ylmethylene))bis(bis(tolylphosphine oxide) were reacted with acetonitrile (100 mL) as solvent at room temperature for 24 h to synthesize ((((6-(4-(((di-p-tolylphosphoyl)(furan-2-yl)methyl)(pyridin-4-yl)amino)phenyl)-1,3,5-triazine-2,4-diyl)bis(4,1-phenylene))bis(azadiyl))bis(furan-2-ylmethylene))bis(di-p-tolylphosphine oxide), with a yield of 63%. The structural formula of the product is as follows:

[0152]

[0153] Example 24: Preparation of flame retardant

[0154] Using TAPT and benzaldehyde as raw materials, in amounts of 23.53 g and 12.72 g respectively, and with 1,4-dioxane (100 mL) as solvent, the reaction was carried out at 60 °C for 24 h to obtain (1Z,1'Z,1”Z)-N,N',N'-((1,3,5-triazine-2,4,6-triyl)tri(benzene-4,1-diyl))tri(1-phenylmethaneamine). This was further reacted with diphenylphosphine oxide, in amounts of 24.73 g and 24.26 g respectively, with acetonitrile (100 mL) as solvent, and the reaction was carried out at room temperature for 24 h to synthesize ((((1,3,5-triazine-2,4,6-triyl)tri(benzene-4,1-diyl))tri(azadiyl))tri(phenylmethylene))tri(diphenylphosphine oxide), with a yield of 60%. The structural formula of the product is as follows:

[0155]

[0156] Example 25: Preparation of flame retardant

[0157] Using TAPT and 2-naphthaldehyde as raw materials, in amounts of 23.53 g and 18.73 g respectively, and with 1,4-dioxane (100 mL) as solvent, the reaction was carried out at 60 °C for 24 h to obtain (1Z,1'Z,1”Z)-N,N',N'-((1,3,5-triazine-2,4,6-triyl)tri(phenyl-4,1-diyl))tri(1-(naphth-2-yl)methane). This was further reacted with diphenylphosphine oxide in amounts of 30.73 g and 32.35 g respectively, with acetonitrile (100 mL) as solvent, and the reaction was carried out at room temperature for 24 h to synthesize (1,3,5-triazine-2,4,6-triacyl)tri(phenyl-4,1-diacyl))tri(azadiacyl)tri(naphth-2-methylene)tri(diphenylphosphine oxide), with a yield of 61%. The structural formula of the product is as follows:

[0158]

[0159] Example 26: Preparation of Flame Retardant

[0160] Using PFPM (prepared in Example 2) and quinoline-6-yl(quinoline-7-yl)phosphine oxide as raw materials, in amounts of 23.53 g and 36.49 g respectively, a solvent method was used with acetonitrile (100 mL) as solvent to react at room temperature for 24 h, synthesizing (((4-(4-((((di(quinoline-7-yl)phosphoryl)(furan-2-yl)methyl)amino)phenyl)-6-(4-(furan-2-yl(quinoline-6-yl(quinoline-7-yl)phosphoryl)methyl)amino)phenyl)-1,3,5-triazin-2-ylphenyl)amino)(furan-2-methyl)(quinoline-7-yl)(quinoline-8-yl)phosphine oxide, with a yield of 58%. The structural formula of the product is as follows:

[0161]

[0162] Example 27: Preparation of Flame Retardant

[0163] Using PFPM (prepared in Example 2) and bis(4-(2-(trimethylsilyl)ethyl)phenyl)phosphonate as raw materials, in amounts of 23.53 g and 52.10 g respectively, bis(4-(2-(trimethylsilyl)ethyl)phenyl)((1S)-((4-(4-(((((R))-(bis(4-(2-(trimethylsilyl)ethyl)phenoxy))))phosphoryl)(furan-2-yl)methyl)amino)phenyl)-6-(4-(((bis(4-(2-(trimethylsilyl)ethyl)phenoxy)phosphoryl)(furan-2-yl)methyl)amino)phenyl)-1,3,5-triazin-2-yl)phenyl)amino)(furan-2-yl)methyl)phosphonate, the yield was 60%. The structural formula of the product is as follows:

[0164]

[0165] Example 28: Preparation of flame retardant

[0166] Using PFPM (prepared in Example 2) and bis(decahydroisoquinoline-6-yl)phosphine oxide as raw materials, in amounts of 23.53 g and 38.91 g respectively, bis(decahydroisoquinoline-6-yl)phosphine oxide was synthesized by solvent method with acetonitrile (100 mL) as solvent at room temperature for 24 h, yielding (((4-(4-((((bis(decahydroisoquinoline-6-yl)phosphoyl)(furan-2-yl)methyl)amino)phenyl)-6-(4-((((decahydroisoquinoline-7))-yl)(decahydroisoquinoline-8-yl)phosphoyl)(furan-2-yl)methyl)amino)phenyl)-1,3,5-triazin-2-yl)phenyl)amino)(furan-2-yl)methyl)bis(decahydroisoquinoline-7-yl)phosphine oxide. The yield was 69%. The structural formula of the product is as follows:

[0167]

[0168] Example 29: Flame retardant properties of flame retardant TTFDO

[0169] Epoxy resin EP51 and the product obtained in Example 7 were mixed at a weight ratio of 90:10 and cured sequentially at 120°C, 150°C, and 180°C for 2 hours in a polytetrafluoroethylene mold with dimensions of 80*10*4 mm to prepare test strips. According to the national combustion test standard ASTM D3801, the flame retardancy rating was UL-94V-0, with t1 of 1.4s and t2 of 2.8s. According to the national combustion test standard ASTM D2863, the limiting oxygen index (LOI) value was 29.3%.

[0170] Example 30: Flame retardant properties of flame retardant TTFDO

[0171] Epoxy resin EP51 and the product obtained in Example 7 were mixed in a weight ratio of 85:15 and cured sequentially at 120°C, 150°C, and 180°C for 2 hours in a polytetrafluoroethylene mold with dimensions of 80*10*4 mm to prepare test strips. According to the national combustion test standard ASTM D3801, the flame retardancy rating was UL-94V-0, with t1 of 1.4s and t2 of 2.8s. According to the national combustion test standard ASTM D2863, the limiting oxygen index (LOI) value was 29.75%.

[0172] Example 31: Flame retardant properties of flame retardant TTFTO

[0173] Epoxy resin EP51 and the product obtained in Example 13 were mixed at a weight ratio of 90:10 and cured sequentially at 120°C, 150°C, and 180°C for 2 hours in a polytetrafluoroethylene mold with dimensions of 80*10*4 mm to prepare test strips. According to the national combustion test standard ASTM D3801, the flame retardant rating was UL-94V-0, where t1 was 0 seconds and t2 was 2.2 seconds. According to the national combustion test standard ASTM D2863, the limiting oxygen index (LOI) value was 28.3%.

[0174] Example 32: Flame retardant properties of flame retardant TTFTO

[0175] Epoxy resin EP51 and the product obtained in Example 13 were mixed in a weight ratio of 85:15 and cured sequentially at 120°C, 150°C, and 180°C for 2 hours in a polytetrafluoroethylene mold with dimensions of 80*10*4 mm to prepare test strips. According to the national combustion test standard ASTM D3801, the flame retardancy rating was UL-94V-0, with t1 being 0.2s and t2 being 3.6s. According to the national combustion test standard ASTM D2863, the limiting oxygen index (LOI) value was 29.19%.

[0176] Example 33: Flame retardant properties of flame retardant DFPTP

[0177] Epoxy resin EP51 and the product obtained in Example 16 were mixed at a weight ratio of 90:10 and cured sequentially at 120°C, 150°C, and 180°C for 2 hours in a polytetrafluoroethylene mold with dimensions of 80*10*4 mm to prepare test strips. According to the national flammability testing standard ASTM D3801, the flame retardant rating was UL-94V-2. According to the national flammability testing standard ASTM D2863, the limiting oxygen index (LOI) value was 27.7%.

[0178] Example 34: Flame retardant properties of flame retardant DFPTP

[0179] Epoxy resin EP51 and the product obtained in Example 16 were mixed in a weight ratio of 85:15 and cured sequentially at 120°C, 150°C, and 180°C for 2 hours in a polytetrafluoroethylene mold with dimensions of 80*10*4 mm to prepare test specimens. According to the national flammability testing standard ASTM D3801, the flame retardant rating was UL-94V-1. According to the national flammability testing standard ASTM D2863, the limiting oxygen index (LOI) value was 28.1%.

[0180] Example 35: Flame retardant properties of flame retardants

[0181] Epoxy resin EP51 and the products obtained in Examples 19-28 were mixed at a weight ratio of 90:10, and then cured sequentially at 120°C, 150°C, and 180°C for 2 hours in a polytetrafluoroethylene mold with dimensions of 80*10*4mm to prepare test specimens. According to the national combustion test standard ASTM D3801, the flame retardancy rating of all specimens reached UL-94V-1.

[0182] The above description is merely a preferred embodiment of the present invention. It should be noted that those skilled in the art can make improvements and modifications without departing from the core technology of the present invention, and such improvements and modifications should also fall within the patent protection scope of the present invention. Any changes within the meaning and scope equivalent to the claims of the present invention should be considered as included within the scope of the claims.

Claims

1. A substance containing P C-bonded phosphorus-nitrogen triazine flame retardants, characterized in that... The structure of the flame retardant is as follows: Wherein, R1 and R2 are phenyl; or R1 and R2 are methyl, n-propyl, or isopropyl; or R1 and R2 are phenoxy or ethyltrimethylsilyl-substituted phenoxy; or R1 and R2 are phenoxy compounds in which the C at position 1 is substituted by an N atom or the C at position 2 is substituted by an N atom, or R1 and R2 are fused cycloalkylaryl groups with an oxygen atom; R3 is 2-furanyl, phenyl, 4-ethylphenyl, 4-propylfuran-2-yl, or 2-naphthyl; The fused cycloalkylaryl group formed with oxygen atoms is a group containing a biphenyl structure formed by the connection of a phenyl group and a phenoxy group.

2. A substance containing P C-bonded phosphorus-nitrogen triazine flame retardants, characterized in that... The flame retardant has one of the following structural formulas: 。 3. A P-containing compound as described in claim 1 The preparation method of C-bonded phosphorus nitrogen triazine flame retardant is characterized by, Includes the following steps: (1) Add 2,4,6-tris(4-aminophenyl)-1,3,5-triazine to 1,4 In dioxane, after dissolution, furfural or furfural analogues are added and stirred at 30–80 °C to obtain 1-(furan-2-yl)-N-(4-(4-(4-(((E)-furan-2-ylmethylene)amino)phenyl)-6-(4-(((Z)-furan)-2-ylmethylene)amino)phenyl)-1,3,5-triazin-2-yl)phenyl)methylimine or 1-(furan-2-yl)-N-(4-(4-((((E)-furan-2-ylmethylene)amino)phenyl)-6-(4-(((Z)-furan)-2-ylmethylene)amino)phenyl)-1,3,5-triazin-2-yl)phenyl)methylimine analogues; wherein, the furfural analogues have the following structural formula: ; (2) Add 1-(furan-2-yl)-N-(4-(4-(4-(((E)-furan-2-ylmethylene)amino)phenyl)-6-(4-((((Z)-furan)-2-ylmethylene)amino)phenyl)-1,3,5-triazin-2-yl)phenyl)methylimine or an analogue of 1-(furan-2-yl)-N-(4-(4-((((E)-furan-2-ylmethylene)amino)phenyl)-6-(4-((((Z)-furan)-2-ylmethylene)amino)phenyl)-1,3,5-triazin-2-yl)phenyl)methylimine to acetonitrile, dissolve, add DPO or a DPO analogue, and stir at 30-80°C to obtain P-containing... C-bonded phosphorus-nitrogen triazine flame retardants, among which the DPO analogue has the following structural formula: The definitions of R1, R2, and R3 are the same as those in claim 1.

4. A P-containing compound according to claim 3 The preparation method of C-bonded phosphorus nitrogen triazine flame retardant is characterized by, 2,4,6-Tris(4-aminophenyl)-1,3,5-triazine, 1,4 The ratio of dioxane to furfural is 14.17–17.71 g: 90–100 mL: 11.52–19.20 g; 2,4,6-Tris(4-aminophenyl)-1,3,5-triazine, 1,4 The ratio of dioxane to furfural analogue is 14.17–17.71 g: 90–100 mL: 12.72–18.73 g.

5. A P-containing compound according to claim 3 The preparation method of C-bonded phosphorus nitrogen triazine flame retardant is characterized by, The ratio of 1-(furan-2-yl)-N-(4-(4-(4-(((E)-furan-2-ylmethylene)amino)phenyl)-6-(4-(((Z)-furan)-2-ylmethylene)amino)phenyl)-1,3,5-triazin-2-yl)phenyl)methyleneimine, acetonitrile, and DPO is 23.53–29.41 g: 90–100 mL: 24.26–32.35 g; The ratio of 1-(furan-2-yl)-N-(4-(4-(4-(((E)-furan-2-ylmethylene)amino)phenyl)-6-(4-(((Z)-furan)-2-ylmethylene)amino)phenyl)-1,3,5-triazin-2-yl)phenyl)methylimine analog, acetonitrile, and DPO was 24.73–30.73 g: 90–100 mL: 24.26–32.35 g; The ratio of 1-(furan-2-yl)-N-(4-(4-(4-(((E)-furan-2-ylmethylene)amino)phenyl)-6-(4-(((Z)-furan)-2-ylmethylene)amino)phenyl)-1,3,5-triazin-2-yl)phenyl)methyleneimine, acetonitrile, and DPO analog is 23.53–26.66 g: 90–100 mL: 25.94–52.10 g; The ratio of 1-(furan-2-yl)-N-(4-(4-(4-(((E)-furan-2-ylmethylene)amino)phenyl)-6-(4-(((Z)-furan)-2-ylmethylene)amino)phenyl)-1,3,5-triazin-2-yl)phenyl)methylimine analog, acetonitrile, and DPO analog is 24.73–30.73 g: 90–100 mL: 25.94–52.10 g.

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