A diphenylphosphoryl fluorinated imide compound, its preparation method and application

Abstract

The present invention discloses a diphenylphosphoryl fluorinated imide compound, a preparation method thereof and an application thereof, belonging to the technical field of flame retardant materials. In the present invention, a fluorinated diamine and a dianhydride monomer are subjected to a ring-opening reaction to generate a fluorinated amic acid compound, and the fluorinated amic acid compound is subjected to gradient thermal imidization treatment to obtain a fluorinated imide compound containing an amino active reaction group; then, the amino group of the fluorinated imide compound undergoes a nucleophilic substitution reaction with the P-Cl bond of diphenylphosphinous chloride to prepare a diphenylphosphoryl fluorinated imide compound, which contains a diphenylphosphoryl group, a fluoromethyl group and an imide ring in its molecular structure. The preparation process of the diphenylphosphoryl fluorinated imide compound does not require the protection of an inert gas, has a low reaction temperature, a short reaction time and a high yield. This diphenylphosphoryl fluorinated imide compound can be used to enhance the flame retardant performance of polymer materials and improve the dielectric properties of the materials.

Description

Technical Field

[0001] The present invention relates to an imide compound and a preparation method thereof, in particular to a diphenylphosphoryl fluorinated imide compound and a preparation method and application thereof. The present invention belongs to the technical field of flame retardant materials. Background Art

[0002] In the information society, there is a need for higher-performance and multi-functional communication electronic devices. In order to meet the requirements of high-frequency signal transmission and high-speed information processing in communication electronic devices, the substrate material needs to meet the requirements of good dielectric properties (low dielectric constant and dielectric loss), and also needs to have good heat resistance and flame retardant properties. Epoxy resin, which is commonly used as one of the substrate materials for printed circuit boards, has good heat resistance, electrical insulation, and corrosion resistance, etc. However, epoxy resin is extremely flammable, which limits its application in some printed circuit board substrate materials with specific requirements for fire protection performance. In addition, it is difficult for existing epoxy resin composites to simultaneously take into account good flame retardant properties and low dielectric properties.

[0003] Chinese Patent CN 110093016A discloses a preparation method of a low dielectric composite material, which uses a soluble imide sizing agent to modify the surface of organic fibers, and then applies it to oxazolidone-modified epoxy resin to prepare a low dielectric organic fiber / epoxy resin composite material, but does not involve the exploration of flame retardant properties. Chinese Patent CN114874266A discloses a biomass flame retardant for epoxy resin and a preparation method thereof. By introducing SiO flexible structure and DOPO structure into the molecular structure of the flame retardant, a renewable biomass material is prepared, thereby improving the toughness, impact resistance and flame retardant properties of epoxy resin, but does not mention the dielectric properties of the epoxy resin composite material. Summary of the Invention

[0004] The technical problem to be solved by the present invention is: overcoming the deficiencies of the prior art, and providing a diphenylphosphoryl fluorinated imide compound and a preparation method and application thereof. By simultaneously introducing diphenylphosphoryl, fluoromethyl and imide ring into the molecular structure, the prepared diphenylphosphoryl fluorinated imide compound has good solubility, processability and thermal stability, and can be used as both a flame retardant for polymer materials and an additive with a low dielectric constant.

[0005] The technical solution of the present invention is:

[0006] A diphenylphosphoryl fluorinated imide compound, the structure of which simultaneously contains diphenylphosphoryl, fluoromethyl and imide ring, and the structural formula of the compound is as shown in Formula I:

[0007]

[0008] In the formula I:

[0009]

[0010] A method for preparing a diphenylphosphoryl fluorinated imide compound. First, a fluorinated amic acid compound is prepared by using a dianhydride and a fluorinated diamine, and then the fluorinated amic acid compound is subjected to gradient thermal imidization treatment to prepare a fluorinated imide compound having an amino group; then, a diphenylphosphoryl fluorinated imide compound is prepared through a nucleophilic substitution reaction between the fluorinated imide compound and a diphenylphosphoryl compound;

[0011] The raw materials for preparing this compound include a fluorinated diamine monomer, a dianhydride monomer, an organic solvent A, a precipitant B, a diphenylphosphoryl compound, a deacidifying agent, an organic solvent C, and a precipitant D;

[0012] The steps of this method are as follows:

[0013] In the first step, the fluorinated diamine monomer, the dianhydride monomer, and the organic solvent A are mixed and reacted to obtain a reaction solution of the fluorinated amic acid compound;

[0014] In the second step, the reaction solution of the fluorinated amic acid compound obtained in the first step is added to an excessive amount of the precipitant B for precipitation, and then filtered and dried to obtain a solid powder of the fluorinated amic acid compound;

[0015] In the third step, the solid powder of the fluorinated amic acid compound obtained in the second step is subjected to gradient thermal imidization treatment, that is, the solid powder of the fluorinated amic acid compound is dehydrated and cyclized at a high temperature to obtain a fluorinated imide compound having an amino group;

[0016] In the fourth step, under ice bath conditions, the diphenylphosphoryl compound and the fluorinated imide compound obtained in the third step are subjected to a nucleophilic substitution reaction in an organic solvent C dissolved with a deacidifying agent. After the reaction is completed, the insoluble hydrochloride generated in the reaction is filtered off to obtain a light yellow transparent reaction solution;

[0017] In the fifth step, the reaction solution obtained in the fourth step is added to the precipitant D for precipitation, and then filtered. The filter cake is washed 2 - 3 times with a saturated sodium bicarbonate solution, and then washed 2 - 3 times with deionized water. Finally, it is dried and ground to obtain a solid powder of the diphenylphosphoryl fluorinated imide compound.

[0018] Preferably, the fluorinated diamine monomer is one of 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl (TFMB), 2,2'-bis(trifluoromethyl)-4,4'-diaminophenyl ether (6FODA), or 2,2-bis(4-aminophenyl)hexafluoropropane (Bis-AP-HFP);

[0019] Preferably, the dianhydride monomer is one of pyromellitic dianhydride (PMDA), 2,3,3',4'-diphenylether tetracarboxylic dianhydride (ODPA), or 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA);

[0020] Preferably, the organic solvent A is at least one of tetrahydrofuran, ethyl acetate, 1,4-dioxane, N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, and dimethyl sulfoxide;

[0021] Preferably, the organic solvent C is at least one of tetrahydrofuran, ethyl acetate, 1,4-dioxane, N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, and dimethyl sulfoxide;

[0022] Preferably, the organic solvent A is tetrahydrofuran and the organic solvent C is N,N-dimethylacetamide;

[0023] Preferably, the precipitant B is at least one of petroleum ether, cyclohexane, n-heptane, n-hexane, and methanol;

[0024] Preferably, the precipitant D is deionized water;

[0025] Preferably, the acid-binding agent is triethylamine or pyridine;

[0026] Preferably, the diphenylphosphinyl compound is diphenylphosphinous chloride;

[0027] Preferably, the molar ratio of the dianhydride monomer to the fluorinated diamine monomer is 1:2;

[0028] Preferably, the molar ratio of the fluorinated imide compound to diphenylphosphinous chloride is 1:2;

[0029] Preferably, the molar ratio of the fluorinated imide compound, diphenylphosphinous chloride, and the acid-binding agent is 1:2:2 to 1:2:4. More preferably, the molar ratio of the fluorinated imide compound, diphenylphosphinous chloride, and the acid-binding agent is 1:2:3;

[0030] Preferably, the volume ratio of the total mass of the fluorinated diamine and the dianhydride monomer to the organic solvent A is 1 g:(10 - 16) mL, more preferably 1 g:13.85 mL;

[0031] Preferably, the volume ratio of the total mass of the fluorinated imide compound and diphenylphosphinous chloride to the organic solvent C is 1 g:(20 - 30) mL, more preferably 1 g:25.73 mL;

[0032] Preferably, the volume ratio of the reaction solution in the second step to the precipitant B is 1 mL:(4 - 9) mL, more preferably 1:6;

[0033] Preferably, the volume ratio of the reaction solution in the fifth step to the precipitant D is 1 mL:(2 - 6) mL, more preferably 1:3;

[0034] Preferably, the reaction temperature in the first step is 5 - 23 °C, and the reaction time in the first step is 1 - 8 h; More preferably, the reaction temperature in the first step is 15 °C, and the reaction time in the first step is 3.5 h;

[0035] Preferably, the ice bath temperature in the fourth step is 0 - 5 °C, and the reaction time in the fourth step is 3 - 24 h; More preferably, the temperature of the ice bath condition in the fourth step is 0 °C, and the reaction time in the fourth step is 4.5 h.

[0036] Preferably, the drying condition in the second step is vacuum drying at 80 - 110 °C for 6 - 12 h; More preferably, the drying condition in the second step is vacuum drying at 80 °C for 8 h;

[0037] Preferably, the drying condition in the fifth step is vacuum drying at 80 - 140 °C for 6 - 12 h; More preferably, the drying condition in the fifth step is vacuum drying at 100 °C for 10 h;

[0038] Preferably, the gradient thermal imidization condition in the third step is 120 °C, 1 h, 150 °C, 1 h, 180 °C, 2 h, and 200 °C, 1 h;

[0039] The gradient thermal imidization condition in the third step can also be 180 °C, 3 h;

[0040] The gradient thermal imidization condition in the third step can also be 180 °C, 2 h, and 200 °C, 2 h;

[0041] More preferably, the gradient thermal imidization condition in the third step is 180 °C, 2 h, and 200 °C, 2 h.

[0042] An application of a diphenylphosphoryl fluorinated imide compound, applying the diphenylphosphoryl fluorinated imide compound to an epoxy resin, that is, mixing the diphenylphosphoryl fluorinated imide compound, the epoxy resin, and a curing agent to prepare an epoxy resin composite material, and using this composite material as a flame - retardant and low - dielectric - constant material. The mass ratio of the epoxy resin to the curing agent is 10:3, the mass of the diphenylphosphoryl fluorinated imide compound is m, and the sum of the masses of the diphenylphosphoryl fluorinated imide compound, the epoxy resin, and the curing agent is n, then m=(2% - 6%)n.

[0043] Beneficial effects

[0044] (1) The present invention provides a preparation method of a diphenylphosphoryl fluorinated imide compound. First, a fluorinated diamine and a dianhydride monomer undergo a ring-opening reaction to form a fluorinated amic acid compound; the fluorinated amic acid compound is subjected to gradient thermal imidization treatment to obtain a fluorinated imide compound containing an amino group; then, a nucleophilic substitution reaction occurs between the amino group of the fluorinated imide compound and the P-Cl bond of diphenylphosphinous chloride to prepare the diphenylphosphoryl fluorinated imide compound.

[0045] (2) The preparation process of the diphenylphosphoryl fluorinated imide compound provided by the present invention does not require inert gas protection, and the reaction conditions are mild, that is, the reaction temperature is low and the reaction time is short; in addition, the operation of this reaction is simple, the energy consumption is low, and the yield is high.

[0046] (3) The structure of the diphenylphosphoryl fluorinated imide compound provided by the present invention is relatively special, that is, it contains diphenylphosphoryl, fluoromethyl and imide ring in its structure, and can achieve the purpose of flame retardancy and dielectric constant reduction simultaneously.

[0047] (4) The imide ring and phenyl rigid groups in the structure of the diphenylphosphoryl fluorinated imide compound provided by the present invention endow it with good heat resistance and a relatively high char residue content at high temperatures; the phosphorus and nitrogen elements in its structure can play a synergistic flame retardant role, thereby improving the flame retardant performance of the matrix resin; in addition, the fluoromethyl in its structure endows it with good solubility and processability, and the fluoromethyl has strong electronegativity, which can reduce the polarization degree of the material, thereby achieving the effect of reducing the dielectric constant and dielectric loss of the material.

[0048] (5) Applying the diphenylphosphoryl fluorinated imide compound provided by the present invention to epoxy resin, an epoxy resin composite material with excellent flame retardancy, low dielectric constant and low dielectric loss is prepared, which can be widely applied to printed circuit board substrate materials. Description of the Drawings

[0049] Figure 1 It is a reaction route diagram for preparing the diphenylphosphoryl fluorinated imide compound in Example 1;

[0050] Figure 2 It is an infrared spectrum diagram of the fluorinated imide compound and the diphenylphosphoryl fluorinated imide compound prepared in Example 1;

[0051] Figure 3 It is for the fluorinated imide compound and the diphenylphosphoryl fluorinated imide compound prepared in Example 1 1 HNMR spectrum diagram;

[0052] Figure 4 It is for the diphenylphosphoryl fluorinated imide compound prepared in Example 1 31 P NMR spectrum diagram;

[0053] Figure 5 Thermogravimetric spectrum of the diphenylphosphoryl fluorinated imide compound prepared in Example 1;

[0054] Figure 6 Variation curves of the dielectric constant with frequency for the sample of the diphenylphosphoryl fluorinated imide compound prepared in Example 1 applied to epoxy resin and the pure epoxy resin sample;

[0055] Figure 7 Variation curves of the dielectric loss with frequency for the sample of the diphenylphosphoryl fluorinated imide compound prepared in Example 1 applied to epoxy resin and the pure epoxy resin sample. Detailed implementation manners

[0056] The present invention will be further described in detail below through specific examples, but the protection scope of the present invention is not limited to the following examples. The following examples are only the preferred implementation manners of the present invention. It should be noted that any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

[0057] In the present invention, unless otherwise defined, all the professional terms used hereinafter have the same meanings as those commonly understood by those skilled in the art. The professional terms used in the present invention are only for the purpose of describing specific examples and are not intended to limit the protection scope of the present invention.

[0058] In the present invention, unless otherwise specifically stated, all kinds of raw materials, reagents, etc. used are commercially available products well known to those skilled in the art.

[0059] Example 1

[0060] Preparation method of the diphenylphosphoryl fluorinated imide compound (PTD), the reaction process is as Figure 1 shown, and the steps of this method are as follows:

[0061] 1) Add 8.10 g of 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl (TFMB) and 150 mL of tetrahydrofuran into a 250 mL three-necked flask, stir at room temperature for 2 min to dissolve it, and then add 2.73 g of pyromellitic dianhydride (PMDA); after reacting at room temperature for 3.5 h, pour the reaction solution into 950 mL of petroleum ether for precipitation, filter, and then vacuum dry at 80 °C for 8 h to obtain a fluorinated amic acid intermediate, and the yield is 94.9%;

[0062] 2) The fluorinated amic acid intermediate obtained in step 1) was subjected to gradient thermal imidization treatment, and the temperature program was set at 180 °C for 2 h and 200 °C for 2 h, and finally a fluorinated imide compound containing amino groups (named PMDA-TFMB) was obtained;

[0063] 3) Under ice bath conditions, 4.55 g of triethylamine and 450 mL of N,N-dimethylacetamide (DMAc) were added to a 1000 mL three-necked flask. Subsequently, 12.33 g of PMDA-TFMB obtained in step 2) was added to the above solution, and it was stirred for 10 min to dissolve it; then a DMAc solution (50 mL) containing 7.10 g of diphenylphosphinyl chloride (DPC) was added dropwise to the above mixture, and the addition was completed after about 15 min; stirring was continued for 4.5 h under ice bath conditions, and white precipitate (i.e., triethylamine hydrochloride) was continuously formed in the system; after the reaction was completed, the above mixture was filtered, and the pale yellow transparent filtrate was collected;

[0064] 4) The pale yellow transparent filtrate collected in step 3) was added to 1500 mL of deionized water to precipitate a pale yellow solid powder; the above mixture was filtered to obtain a crude product, and the crude product was washed 2-3 times with water and saturated sodium bicarbonate respectively, dried and ground to obtain a solid powder of diphenylphosphinyl fluorinated imide compound (named PTD), and the yield was 83.1%.

[0065] The PMDA-TFMB obtained in step 2) of Example 1 was characterized by infrared spectroscopy and 1 1H NMR nuclear magnetic resonance hydrogen spectrum, and the results showed that the obtained product was consistent with the expected structural formula. Figure 2 The absorption peaks at 3488 and 3388 cm -1 were the N-H stretching vibrations of aromatic primary amines, and the absorption peak at 1629 cm -1 was the N-H bending vibration of aromatic primary amines and overlapped with the skeletal vibration of the benzene ring; the absorption peaks at 1336 and 1260 cm -1 were the Ar-N stretching vibrations of aromatic primary amines; the absorption peaks at 1780 and 1728 cm -1 were the asymmetric and symmetric stretching vibrations of C=O in the imide ring, the absorption peak at 1370 cm -1 was the C-N stretching vibration of the imide ring, and the absorption peak at 725 cm -1 was the characteristic absorption peak of the bending vibration of C=O in the imide ring; the many sharp peaks at 1170-1050 cm -1 belonged to the stretching vibration of the C-F bond; the absorption peak at 897 cm -1 was the out-of-plane deformation vibration of N-H of aromatic primary amines; the absorption peak at 824 cm -1 was the para-substitution of the benzene ring. In addition, Figure 3The peak at 8.49 ppm is the proton peak on the benzene ring of the dianhydride, the multiplet at 8.18 - 6.69 ppm is the proton peak on the benzene ring of the diamine, and the peak at 5.75 ppm is the active hydrogen proton peak of the terminal amino group. The ratio of the number of protons is 1:6:2, which is consistent with the theoretical value. Therefore, combining the results of the infrared spectrum and 1 the H NMR, it is proved that PMDA-TFMB was successfully synthesized.

[0066] Step 2) The hydrogen spectrum of PMDA-TFMB is as follows: 1 H NMR (600 MHz, DMSO) δ 8.49 ppm (d, J = 17.2 Hz, 1H), 8.18 - 7.53 ppm (m, 3H), 7.11 - 6.69 ppm (m, 3H), 5.75 ppm (s, 2H).

[0067] The diphenylphosphoryl fluorinated imide compound PTD obtained in step 4) of Example 1 was characterized by infrared spectroscopy and 1 1H NMR nuclear magnetic resonance hydrogen spectrum, and the results showed that the obtained product was consistent with the expected structural formula. Figure 2 The absorption peaks at 1780 and 1728 cm -1 are the asymmetric and symmetric stretching vibrations of C=O of the imide ring, the absorption peak at 1370 cm -1 is the C-N stretching vibration of the imide ring, and the absorption peak at 725 cm -1 is the characteristic absorption peak of the bending vibration of C=O of the imide ring; the absorption peak at 1616 cm -1 is the N-H bending vibration of aromatic secondary amine and overlaps with the skeletal vibration of the benzene ring, and the absorption peak at 1260 cm -1 is the Ar-N stretching vibration of aromatic secondary amine; the many sharp peaks at 1170 - 1050 cm -1 belong to the stretching vibration of the C-F bond; the absorption peaks at 824 and 690 cm -1 are the para-substitution and mono-substitution peaks of the benzene ring respectively; the smaller absorption peak at 1437 cm -1 is the characteristic peak of the P-Ph bond; the P=O stretching vibration peak at about 1300 - 1230 cm -1 is less obvious in Figure 2 and overlaps with the stretching vibration region of the Ar-N bond of aromatic amine. In addition, the deformation vibration peak (1535 cm -1 ) of aromatic secondary amide (O=P-)N-H and the P-N characteristic peak (958 cm -1 ) appear in the spectrum, while the N-H stretching vibration and out-of-plane deformation vibration of aromatic primary amine disappear. Figure 3The peak at 8.50 ppm is the proton peak on the benzene ring of the dianhydride, and the multiplet peaks at 8.18 - 6.95 ppm are the proton peaks on the benzene rings of the diamine and the benzene ring of the diphenylphosphoryl group. The peaks at 6.92 - 6.71 ppm are the active hydrogen proton peaks of O=P-NH-. The ratio of the number of protons is 1:16:1, which is consistent with the theoretical value. The 31 31P NMR( Figure 4 ) spectrum shows that a singlet appears at a chemical shift of 22.60 ppm, indicating that the phosphorus chemical environment in the final product of Example 1 is the same and the structure is single. Therefore, combining the results of the infrared spectrum, 1 1H NMR and 31 31P NMR fully proves the successful synthesis of the diphenylphosphoryl fluorinated imide compound PTD.

[0068] The hydrogen spectrum of PTD is as follows: 1 1H NMR (600 MHz, DMSO) δ 8.50 ppm (t, J = 17.8 Hz, 1H),

[0069] 8.18 - 7.83 ppm (m, 3H), 7.80 - 7.42 ppm (m, 12H), 7.08 - 6.95 ppm (m, 1H), 6.92 - 6.71 ppm (m, 1H); The phosphorus spectrum of PTD is: 31 31P NMR (243 MHz, DMSO) δ 22.60 ppm.

[0070] Under a nitrogen atmosphere, the thermal stability of PTD was characterized. From Figure 5 the thermogravimetric spectrum, it can be seen that the initial decomposition temperature (the temperature at which the weight loss is 5 wt.%) of PTD is 239 °C, and the char residue at 800 °C is 31.1%, indicating that PTD has good thermal stability.

[0071] From the above examples, it can be seen that the preparation process of the diphenylphosphoryl fluorinated imide compound provided by the present invention is easy to operate, the reaction conditions are mild, the energy consumption is low, and it is easy to control; the temperature setting of the gradient thermal imidization process is relatively low, and the obtained diphenylphosphoryl fluorinated imide compound has a high yield, good thermal stability, and a high char residue at high temperatures.

[0072] Application Example 1

[0073] 2.65 g of PTD was added to 100 g of bisphenol A epoxy resin E-44, and stirred at 140 °C for 1.5 h. The system gradually became homogeneous and transparent. Then, 30 g of 4,4'-diaminodiphenyl sulfone curing agent was added to the mixture, and rapidly stirred until the curing agent was completely dissolved. During the dissolution of the curing agent, vacuum was simultaneously applied to remove the gas in the system. After the curing agent was completely dissolved, it was quickly cast into a preheated mold and cured at 180 °C for 4 h. After cooling and demolding, an epoxy resin composite material with a PTD addition amount of 2% was obtained.

[0074] Application Example 2

[0075] 5.42 g of PTD was added to 100 g of bisphenol A epoxy resin E-44, and stirred at 140 °C for 1.5 h. The system gradually became homogeneous and transparent. Then, 30 g of 4,4'-diaminodiphenyl sulfone curing agent was added to the mixture, and rapidly stirred until the curing agent was completely dissolved. During the dissolution of the curing agent, vacuum was simultaneously applied to remove the gas in the system. After the curing agent was completely dissolved, it was quickly cast into a preheated mold and cured at 180 °C for 4 h. After cooling and demolding, an epoxy resin composite material with a PTD addition amount of 4% was obtained.

[0076] Application Example 3

[0077] 8.30 g of PTD was added to 100 g of bisphenol A epoxy resin E-44, and stirred at 140 °C for 1.5 h. The system gradually became homogeneous and transparent. Then, 30 g of 4,4'-diaminodiphenyl sulfone curing agent was added to the mixture, and rapidly stirred until the curing agent was completely dissolved. During the dissolution of the curing agent, vacuum was simultaneously applied to remove the gas in the system. After the curing agent was completely dissolved, it was quickly cast into a preheated mold and cured at 180 °C for 4 h. After cooling and demolding, an epoxy resin composite material with a PTD addition amount of 6% was obtained.

[0078] Comparative Example 1

[0079] 100 g of bisphenol A epoxy resin E-44 was heated to 140 °C, and then 30 g of 4,4'-diaminodiphenyl sulfone curing agent was added, and rapidly stirred until the curing agent was completely dissolved. During the dissolution of the curing agent, vacuum was simultaneously applied to remove the gas in the system. After the curing agent was completely dissolved, it was quickly cast into a preheated mold and cured at 180 °C for 4 h. After cooling and demolding, a pure epoxy resin composite material was obtained.

[0080] The oxygen index and peak heat release rate of the epoxy resin composite materials obtained in Comparative Example 1, Application Example 1, Application Example 2, and Application Example 3 were respectively tested by the test methods in GB / T 2406-93 and ISO 5660, and the results are shown in Table 1.

[0081] Table 1 shows the flame retardancy of epoxy resin composites

[0082]

[0083] It can be seen from Table 1 that, compared with Comparative Example 1, the oxygen index of Application Examples 1, 2, and 3 increased significantly, and the peak value of the heat release rate gradually decreased, indicating that PTD exerted a good flame retardant effect in the epoxy resin composites.

[0084] The dielectric constant and dielectric loss versus frequency curves of the epoxy resin composites obtained from Comparative Example 1, Application Example 1, Application Example 2, and Application Example 3 were respectively tested using a precision impedance analyzer (WK 6500B, UK), and the results are respectively as Figure 6 and 7 shown. It can be seen from Figure 6 and 7 that when PTD is added to epoxy resin, within 10 3 ~10 7 Hz, PTD can significantly reduce the dielectric constant and dielectric loss of the epoxy resin composites.

[0085] In summary, the PTD-modified epoxy resin composites have good flame retardancy, low dielectric constant and dielectric loss. Therefore, PTD can be used as a functional additive with flame retardancy and low dielectric constant and applied to epoxy resin composites.

Claims

1. A diphenylphosphoryl fluorinated imide compound, characterized in that The structural formula of the compound is as follows: Wherein, 2. A method for preparing the diphenylphosphoryl fluorinated imide compound according to claim 1, characterized in that: The raw materials for preparing the compound include a fluorinated diamine monomer, a dianhydride monomer, an organic solvent A, a precipitant B, a diphenylphosphoryl compound, a deacidifying agent, an organic solvent C, and a precipitant D; The steps of the method are as follows: In the first step, the fluorinated diamine monomer, the dianhydride monomer, and the organic solvent A are mixed and reacted to obtain a reaction solution of a fluorinated amic acid compound; In the second step, the reaction solution of the fluorinated amic acid compound obtained in the first step is added to an excessive amount of the precipitant B for precipitation, and then filtered and dried to obtain a solid powder of the fluorinated amic acid compound; In the third step, the solid powder of the fluorinated amic acid compound obtained in the second step is subjected to gradient thermal imidization treatment to obtain a fluorinated imide compound with an amino group; In the fourth step, under ice bath conditions, the diphenylphosphoryl compound and the fluorinated imide compound obtained in the third step are subjected to a nucleophilic substitution reaction in an organic solvent C containing a deacidifying agent. After the reaction is completed, the insoluble hydrochloride generated in the reaction is removed by filtration to obtain a pale yellow transparent reaction solution; In the fifth step, the reaction solution obtained in the fourth step is added to the precipitant D for precipitation, and then filtered. The filter cake is washed 2 - 3 times with a saturated sodium bicarbonate solution, and then washed 2 - 3 times with deionized water. Finally, it is dried and ground to obtain a diphenylphosphoryl fluorinated imide compound; In the first step, the fluorinated diamine monomer is one of 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl (TFMB), 2,2'-bis(trifluoromethyl)-4,4'-diaminophenyl ether (6FODA), or 2,2-bis(4-aminophenyl)hexafluoropropane (Bis-AP-HFP); The dianhydride monomer is one of pyromellitic dianhydride (PMDA), 2,3,3',4'-diphenylether tetracarboxylic dianhydride (ODPA), or 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA); The organic solvent A is at least one of tetrahydrofuran, ethyl acetate, 1,4-dioxane, N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, and dimethyl sulfoxide; The molar ratio of the dianhydride monomer to the fluorinated diamine monomer is 1:2; The volume ratio of the total mass of the fluorinated diamine and the dianhydride monomer to the organic solvent A is 1 g:(10 - 16) mL; The volume ratio of the total mass of the fluorinated diamine and the dianhydride monomer to the organic solvent A is 1 g:13.85 mL; The reaction temperature of the first step is 5 - 23 °C, and the reaction time of the first step is 1 - 8 h; The reaction temperature of the first step is 15 °C, and the reaction time of the first step is 3.5 h; In the second step, the precipitant B is at least one of petroleum ether, cyclohexane, n-heptane, n-hexane, and methanol; The volume ratio of the reaction solution in the second step to the precipitant B is 1 mL:(4 - 9) mL; The volume ratio of the reaction solution in the second step to the precipitant B is 1:

6.

3. The preparation method of a diphenylphosphoryl fluorinated imide compound according to claim 2, wherein: In the third step described above, the gradient thermal imidization conditions of the third step are 120 °C for 1 h, 150 °C for 1 h, 180 °C for 2 h, and 200 °C for 1 h.

4. A method for preparing a diphenylphosphoryl fluorinated imide compound according to claim 2, characterized in that: The gradient thermal imidization conditions of the third step are 180 °C for 3 h.

5. A method for preparing a diphenylphosphoryl fluorinated imide compound according to claim 2, characterized in that: The gradient thermal imidization conditions of the third step are 180 °C for 2 h and 200 °C for 2 h.

6. A method for preparing a diphenylphosphoryl fluorinated imide compound according to claim 2, characterized in that: In the fourth step described above, the organic solvent C is at least one of tetrahydrofuran, ethyl acetate, 1,4-dioxane, N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, and dimethyl sulfoxide; The acid-binding agent is triethylamine or pyridine; The diphenylphosphoryl compound is diphenylphosphinous chloride; The molar ratio of the fluorinated imide compound to diphenylphosphinous chloride is 1:2; The molar ratio of the fluorinated imide compound, diphenylphosphinous chloride to the acid-binding agent is 1:2:2 to 1:2:4; The volume ratio of the total mass of the fluorinated imide compound and diphenylphosphinous chloride to the organic solvent C is 1 g:(20 - 30) mL; The ice bath temperature of the fourth step is 0 - 5 °C, and the reaction time of the fourth step is 3 - 24 h; In the fifth step described above, the precipitating agent D is deionized water; The volume ratio of the reaction solution in the fifth step to the precipitating agent D is 1 mL:(2 - 6) mL.

7. A method for preparing a diphenylphosphoryl fluorinated imide compound according to claim 6, characterized in that: In the fourth step described above, the molar ratio of the fluorinated imide compound, diphenylphosphinous chloride to the acid-binding agent is 1:2:3; The volume ratio of the total mass of the fluorinated imide compound and diphenylphosphinous chloride to the organic solvent C is 1 g:25.73 mL; The temperature of the ice bath condition in the fourth step is 0 °C, and the reaction time of the fourth step is 4.5 h; The volume ratio of the reaction solution in the fifth step to the precipitating agent D is 1:

3.

8. An application of the diphenylphosphoryl fluorinated imide compound according to claim 1, characterized in that: The diphenylphosphoryl fluorinated imide compound is applied to epoxy resin, and the diphenylphosphoryl fluorinated imide compound, epoxy resin and curing agent are mixed to prepare an epoxy resin composite material. The mass ratio of epoxy resin to curing agent is 10:

3. The mass of the diphenylphosphoryl fluorinated imide compound is m, and the sum of the masses of the diphenylphosphoryl fluorinated imide compound, epoxy resin and curing agent is n, then m = (2% - 6%)n.

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