Cyanide-containing phosphate derivative as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of flame retardance of high polymer materials, and particularly relates to a cyanogen-containing phosphate derivative as well as a preparation method and application thereof. The cyanogen-containing phosphate derivative provided by the invention simultaneously contains phosphorus and nitrogen elements, can obviously improve the flame retardant property of the epoxy resin, and has small influence on the environment and is more environment-friendly compared with the epoxy resin added with a halogen type flame retardant. The cyanogen-containing phosphate ester derivative contains a flexible structure, so that the epoxy resin composition added with the cyanogen-containing phosphate ester derivative has good mechanical property retentivity, and the epoxy resin composition provided by the invention has the characteristics of high flame retardance and high mechanical property retentivity, and can be used for preparing epoxy resin products.

Description

Technical Field

[0001] This invention belongs to the field of flame retardant technology of polymer materials, and more specifically, relates to a cyanophosphate derivative, its preparation method and application. Background Technology

[0002] Epoxy resin (EP) possesses excellent mechanical properties, chemical resistance, and processability, as well as superior electrical insulation, bond strength, and dimensional stability. Therefore, it is widely used in furniture, coatings, construction, transportation, electronics, aerospace, and other fields. However, its oxygen index (LOI) is only around 20%, failing any vertical burning (UL-94) rating test, indicating that it is a flammable material. This limitation hinders its development in various application areas.

[0003] In the past, to achieve flame retardant effects, halogenated flame retardant additives were added to epoxy resins (EP) to reduce their flammability. However, due to the toxicity of halogenated flame retardant additives, they release toxic gases and carcinogens during combustion, causing significant pollution and damage to the environment. This conflicts with sustainability and green chemistry. Therefore, halogen-free flame-retardant epoxy resins are receiving increasing attention. Flame retardant additives containing phosphorus and nitrogen are more environmentally friendly and show satisfactory flame retardant effects. Although they improve flame retardant performance, their compatibility with the matrix resin can lead to a decrease in mechanical properties and thermal stability. In the event of a fire, epoxy resin (EP) releases a large amount of heat and harmful fumes, causing casualties and property damage. Therefore, providing a green, environmentally friendly, highly efficient flame retardant with high mechanical property retention for epoxy resin materials is an urgent problem to be solved by the industry. Summary of the Invention

[0004] The purpose of this invention is to solve the above-mentioned technical problems and provide a green, environmentally friendly, highly efficient flame retardant, and mechanically stable cyanophosphate derivative for epoxy resin materials.

[0005] Another object of the present invention is to provide a preparation process for the above-mentioned cyanophosphate derivatives.

[0006] Another object of the present invention is to provide applications of the above-mentioned cyanophosphate derivatives.

[0007] Another object of the present invention is to provide an epoxy resin composition.

[0008] Another object of the present invention is to provide a method for preparing the above-described epoxy resin composition.

[0009] This invention is achieved through the following technical solution:

[0010] A cyanophosphate derivative having any of the following molecular structures:

[0011] In this context, R1, R2, R3, and R4 represent groups containing aromatic structures, and T represents groups containing phosphate esters.

[0012] Preferably, R1 is selected from any of the following structures. R2 is selected from any of the following structures. R3 is selected from any of the following structures. R4 is selected from any of the following structures. The phosphate-containing group is selected from any of the following structures.

[0013]

[0014] Preferably, the structure of the cyanophosphate derivative is as follows:

[0015]

[0016]

[0017]

[0018] The cyanophosphate derivatives provided by this invention exhibit highly efficient flame retardant effects. The underlying principle is speculated to be: in the condensed phase, the cyano group may undergo cyclization under high-temperature pyrolysis to form triazine and phthalonitrile compounds, thereby enhancing charring ability; secondly, phosphate esters, upon high-temperature pyrolysis, form metaphosphoric acid and polyphosphoric acid, both of which are retained in the char residue; synergistically with the cyano group, they contribute to the formation of a dense char layer structure, effectively isolating external oxygen and heat penetration. In the gas phase, the cyano group, upon high-temperature pyrolysis, forms non-flammable gases (such as NH3), which act as a diluent, reducing the concentration of O2 and other combustible gases; the phosphate esters, upon high-temperature pyrolysis, generate phosphorus-containing free radicals (such as PO· and HPO·), which quench the flame by capturing active free radicals (such as H· and OH·).

[0019] This invention provides a method for preparing the above-mentioned cyanophosphate derivatives, comprising the following steps:

[0020] S1: An aromatic compound containing hydroxyl and aldehyde groups undergoes a substitution reaction with epichlorohydrin under phase catalyst I. An alkaline solution is added to obtain intermediate I.

[0021] S2: Intermediate I is dissolved in organic solvent I, and in phase catalyst II, it undergoes a condensation reaction with malononitrile to generate intermediate II;

[0022] S3: Intermediate II and phosphate ester compounds undergo an addition reaction in phase catalyst III to generate the target product, namely a cyanophosphate ester derivative.

[0023] Preferably, in S1, the phase catalyst I is selected from at least one of tetrabutylammonium bromide, benzyltriethylammonium chloride, hexadecyltrimethylammonium bromide, and trioctylmethylammonium chloride.

[0024] Preferably, in S1, the alkaline solution is selected from NaOH solution; the molar ratio of the aromatic compound containing hydroxyl and aldehyde groups, epichlorohydrin, phase catalyst I and NaOH is 1:(1-20):(0.1-1):(1-12).

[0025] More preferably, the NaOH solution is selected from 40wt% NaOH solution.

[0026] Preferably, in S1, the temperature of the substitution reaction is 25–100°C, the reaction time is 15–24 h under a nitrogen atmosphere.

[0027] Preferably, the aromatic compound containing hydroxyl and aldehyde groups in S1 is selected from at least one of the following structures: in - represents a hydroxyl group (-OH), and - represents an aldehyde group (-CHO).

[0028] Preferably, in S2, the organic solvent I is selected from at least one of anhydrous ethanol, methanol, isopropanol, cyclohexane, dichloromethane, N,N-dimethylformamide, dimethyl sulfoxide, and pyridine.

[0029] Preferably, in S2, the phase catalyst II is selected from at least one of potassium carbonate, sodium carbonate, 2-ethyl-4-methylimidazole, 2-methylimidazole, 1-methylimidazole, piperidine, potassium sorbate, potassium alum, ammonium acetate, benzyltriethylammonium chloride, 1-butyl-3-methylimidazole bromide, triethylamine, and copper sulfate.

[0030] Preferably, in S2, the molar ratio of intermediate I, malononitrile, and phase catalyst II is 1:(1-4):(0.05-0.3).

[0031] Preferably, in S2, the temperature of the condensation reaction is 25–60°C, the reaction time is 2–4 hours under a nitrogen atmosphere.

[0032] Preferably, in S3, the phosphate ester compound is selected from at least one of triethyl phosphite, trimethyl phosphite, diethyl phosphite, dimethyl phosphite, diphenyl phosphite, triphenyl phosphite, and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide.

[0033] Preferably, the phase catalyst III is selected from at least one of perchloric acid, dodecylmolybdic acid, phosphomolybdic acid, molybdenum phosphate, dodecyltungstic acid, phosphotungstic acid, tungstic phosphate, dodecyltungstic silicic acid, silicotungstic acid, and ammonium dodecylmolybdic acid.

[0034] Preferably, in S3, the molar ratio of intermediate II, phosphate ester compound, and phase catalyst III is 1:(1-15):(0.01-0.12).

[0035] Preferably, in S3, the temperature of the addition reaction is 25–80°C, the reaction time is 1–4 h under a nitrogen atmosphere.

[0036] This invention provides the application of the above-mentioned cyanophosphate derivatives in the preparation of epoxy resin compositions.

[0037] The present invention also provides an epoxy resin composition comprising the above-mentioned cyanophosphate derivative and epoxy resin.

[0038] Preferably, the epoxy resin composition further includes a curing agent; the mass ratio of the cyanophosphate derivative, epoxy resin monomer and curing agent is (1-20):(10-20):(1-10).

[0039] Preferably, the epoxy resin monomer is selected from at least one of E51, E44, E42 or E31.

[0040] Preferably, the curing agent is selected from at least one of substituted alkane, amine compound, or acid anhydride.

[0041] Specifically, the curing agent is selected from at least one of 4,4'-diaminodiphenylmethane (DDM), 4,4'-diaminodiphenyl sulfone (DDS), polyetheramine (PEA), amino-terminated trimethylolpropane tripropylene glycol ether, hexahydrophthalic anhydride (HHPA) or tetrahydrophthalic anhydride (THPA).

[0042] The present invention also provides a method for preparing the above-mentioned epoxy resin composition, wherein the components are mixed evenly and cured at 100-200°C for 4-10 hours.

[0043] Compared with the prior art, the present invention has the following advantages:

[0044] The cyanophosphate derivatives provided by this invention are characterized by being green and halogen-free flame retardant. The raw materials used are derived from renewable resources, making them inexpensive and abundant. These cyanophosphate derivatives also contain phosphorus and nitrogen, which significantly improve the flame retardant properties of epoxy resins. Compared to epoxy resins with added halogenated flame retardants, they have less environmental impact and are more environmentally friendly. The cyanophosphate derivatives contain a flexible structure, giving the epoxy resin compositions with added cyanophosphate derivatives good mechanical property retention. The epoxy resin compositions provided by this invention are characterized by high flame retardancy and high mechanical property retention, and can be used to prepare epoxy resin products. Attached Figure Description

[0045] Figure 1 3-Methoxy-4-(epoxypropane)benzaldehyde (EV) 1 H-NMR spectrum.

[0046] Figure 2 It is 2-[3-methoxy-4-(epoxypropoxy)benzyl]malononitrile (EVM) 1 H-NMR spectrum.

[0047] Figure 3 It is (EVPM) of diethyl (2,2-dicyano-1-[3-methoxy-4-(epoxypropoxy)phenyl]ethyl)phosphonate. 1 H-NMR spectrum.

[0048] Figure 4 It is a diethyl (2,2-dicyano-1-[3-methoxy-4-(epoxypropoxy)phenyl]ethyl)phosphonate (EVPM) and triethyl phosphite (TEP). 31 P-NMR spectrum. Detailed Implementation

[0049] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention. These all fall within the scope of protection of the present invention.

[0050] All raw materials used in this invention are commercially available:

[0051] Test methods:

[0052] (1) Vertical oxygen index: UL94 was tested according to GB / T 2408-2008 standard, with a sample size of 120×13×3mm. 3 .

[0053] (2) Limiting Oxygen Index (LOI): GB / T 2406-2009 was adopted, and the sample size was 80×6.5×3mm. 3 .

[0054] (3) Tensile property test: GB / T1040.2-2006 standard was adopted, and the sample size was the 5A type sample in the standard.

[0055] (4) Impact strength test: GB / T 1843-2008 standard was adopted, and the sample size was 80×10×4mm. 3 Unnotched impact splines.

[0056] (5) Thermogravimetric analysis (TGA) test temperature range 30℃-800℃, heating rate 10K / min, nitrogen atmosphere.

[0057] Example 1

[0058] S1: Take 30.43g vanillin, 185.04g epichlorohydrin, and 4.5556g benzyltriethylammonium chloride. Purge with nitrogen gas at 80℃ and react for 4 hours. Then add 35ml of 40wt% NaOH solution, lower the reaction temperature to 55℃, turn off the nitrogen gas, and react for 17 hours to obtain a light yellow crude product of EV.

[0059] Add an appropriate amount of water to the system to dissolve the salt produced in the reaction, separating the organic phase from the aqueous phase. Then, add ethyl acetate to the aqueous phase to extract the EV. Combine the organic and aqueous phases, add saturated brine to the organic phase for washing to remove the phase transfer catalyst, NaOH, and other residual substances. Test the pH value with pH paper until the pH value is neutral, at which point the washing is complete. Finally, add an appropriate amount of anhydrous NaSO4 for drying.

[0060] After drying for a full day, the desiccant is removed by filtration, and the ethyl acetate solvent is evaporated using a rotary evaporator to obtain a solid of 3-methoxy-4-(epoxypropane)benzaldehyde (EV).

[0061] The chemical reaction equation for the synthesis of 3-methoxy-4-(epoxypropane)benzaldehyde (EV) in this invention is as follows:

[0062]

[0063] S1 product 1 The characterization results of H-NMR are as follows Figure 1 As shown: the absorption peaks are δ = 2.8 ppm, δ = 2.9 ppm, δ = 3.4 ppm, δ = 4.1 ppm, δ = 4.3 ppm (the three hydrogens on the epoxypropoxy group); δ = 7.1 ppm - 7.5 ppm (hydrogens on the benzene ring); δ = 9.8 ppm (hydrogens on the aldehyde group).

[0064] Therefore, 3-methoxy-4-(epoxypropane)benzaldehyde (EV) was prepared through the S1 preparation process.

[0065] S2: Take 10.41g of EV obtained from S1, 3.4g of malononitrile, and 0.5494g of 2-ethyl-4-methylimidazolium and place them in a three-necked flask. Add 100mL of anhydrous ethanol and purge with nitrogen gas at 60℃. After reacting for 2h, a yellow solid precipitates from the solution. Filter the solid to obtain 2-[3-methoxy-4-(epoxypropoxy)benzylidene]malononitrile (EVM).

[0066] The chemical reaction equation for the synthesis of 2-[3-methoxy-4-(epoxypropoxy)benzyl]malononitrile (EVM) in this invention is as follows:

[0067]

[0068] S2 product 1 The characterization results of H-NMR are as follows Figure 2 As shown: the absorption peaks are δ = 2.8 ppm, δ = 2.9 ppm, δ = 3.4 ppm, δ = 4.1 ppm, δ = 4.3 ppm (three hydrogens on the epoxypropoxy group); δ = 7.1-7.5 ppm (hydrogens on the benzene ring); δ = 7.67-7.70 ppm (hydrogens on the double bond).

[0069] Therefore, 2-[3-methoxy-4-(epoxypropoxy)benzyl]malononitrile (EVM) was prepared through the S2 preparation process.

[0070] S3: Take 1.28 g of EVM obtained from S2, 8.62 g of triethyl phosphite (TEP), and 0.25 g of dodecyl molybdate, and react them at room temperature under nitrogen purging for 19 h. Add petroleum ether, and separate the catalyst and excess TEP from the resulting mixture by filtration. Repeat the washing three times to obtain the crude product.

[0071] The crude product was passed through a silica gel column and eluted with petroleum ether:ethyl acetate (1:1). The product was purified by chromatography to obtain diethyl(2,2-dicyano-1-[3-methoxy-4-(epoxypropoxy)phenyl]ethyl)phosphonate (EVPM).

[0072] The chemical reaction equation for the synthesis of diethyl (2,2-dicyano-1-[3-methoxy-4-(epoxypropoxy)phenyl]ethyl)phosphonate (EVPM) in this invention is as follows:

[0073]

[0074] S3 product 1 The characterization results of H-NMR are as follows: Figure 3 The absorption peaks are shown as follows: δ = 1.36 ppm, δ = 4.17 ppm (two hydrogens on triethyl phosphite); δ = 2.76 ppm, δ = 2.92 ppm, δ = 3.47-3.5 ppm, δ = 4.26-4.50 ppm (three hydrogens on propylene oxide); δ = 3.4 ppm, δ = 4.04 ppm (two hydrogens formed by double bond breakage); δ = 6.93-7.10 ppm (hydrogens on the benzene ring). The 31P-NMR characterization result is: absorption peak at δ = 19.4 ppm.

[0075] Therefore, it can be seen that diethyl(2,2-dicyano-1-[3-methoxy-4-(epoxypropoxy)phenyl]ethyl)phosphonate (EVPM) was prepared through the S3 preparation process.

[0076] Example 2:

[0077] S1: 3,4-bis(epoxypropane-2-ylmethoxy)benzaldehyde (PE) was prepared by replacing 30.43g of vanillin with 27.62g of protocatechuic aldehyde, 185.04g of epichlorohydrin, 9g of benzyltriethylammonium chloride, and 70ml of 40wt% NaOH solution, under the same conditions as S1 in Example 1. The chemical reaction equation is as follows:

[0078]

[0079] S2: Take 12.51g of PE obtained from S1, along with 3.4g of malononitrile and 0.5494g of 2-ethyl-4-methylimidazolium, and follow the same conditions as S2 in Example 1 to prepare 2-[3,4-bis(epoxypropane-2-ylmethoxy)benzylene]malononitrile, abbreviated as PEM. The chemical reaction equation is as follows:

[0080]

[0081] S3: Take 2.98g of PEM obtained in S2, 8.31g of triethyl phosphite (TEP), and 0.25g of dodecylmolybdic acid, and perform the same procedures as S2 in Example 1, to prepare diethyl[1-(3,4-bis(epoxypropane-2-ylmethoxy)phenyl]-2,2-dicyanethylphosphonate (PEPM). The chemical reaction equation is as follows:

[0082]

[0083] Example 3:

[0084] S1: 33.23g of 2,5-dihydroxyterephthalaldehyde replaced 30.43g of vanillin, 185.04g of epichlorohydrin, 9g of benzyltriethylammonium chloride, and 70ml of 40wt% NaOH solution were used. Other conditions were the same as in S1 of Example 1 to prepare 2,5-bis(epoxypropane-2-ylmethoxy)benzene-1,4-dicarboxaldehyde, abbreviated as DE. The chemical reaction equation is as follows:

[0085]

[0086] S2: 13.91 g of DE obtained in S1, along with 6.8 g of malononitrile and 1.0988 g of 2-ethyl-4-methylimidazolium, were used. Other conditions were the same as in S2 of Example 1 to prepare 2,2'-[(2,5-bis(epoxypropane-2-ylmethoxy)-1,4-phenylene)bis(methylethylene)]bismalononitrile, abbreviated as DEM. The chemical reaction equation is as follows:

[0087]

[0088] S3: Take 3.74 g of DEM obtained in S2, 16.6 g of triethyl phosphite (TEP), and 0.5 g of dodecylmolybdic acid, and perform the same procedures as in S3 of Example 1 to prepare tetraethyl[(2,5-bis(epoxypropane-2-ylmethoxy)-1,4-phenylene)bis(2,2-dicyanoethane-1,1-diyl)]bisphosphonate (DEPM). The chemical reaction equation is as follows:

[0089]

[0090] Example 4:

[0091] S1: 30.43g of vanillin, 370.09g of epichlorohydrin, 9g of benzyltriethylammonium chloride, and 105ml of 40wt% NaOH solution were replaced with 33.23g of 2,4,6-tris(epoxypropane-2-ylmethoxy)-1,3,5-benzyltricarboxaldehyde (TE) under the same conditions as in Example 1. The chemical reaction equation is as follows:

[0092]

[0093] S2: Take 18.92g of TE obtained from S1, along with 9.91g of malononitrile and 1.0988g of 2-ethyl-4-methylimidazolium, and follow the same conditions as S2 in Example 1 to prepare 2,2',2”-((2,4,6-tris(ethylene oxide-2-ylmethoxy))benzene-1,3,5-triyl)tris(methylene)trimalononitrile, abbreviated as TEM. The chemical reaction equation is as follows:

[0094]

[0095] S3: Take 5.22g of TEM obtained in S2, 24.9g of triethyl phosphite (TEP), and 0.5g of dodecyl molybdate, and perform the same procedures as in S3 of Example 1 to prepare hexaethyl tetraphosphate ((2,4,6-tris(ethylene oxide-2-ylmethoxy))benzene-1,3,5-triyl)tris(phosphonate) (TEPM). The chemical reaction equation is as follows:

[0096]

[0097] Application Example 1:

[0098] 16g of diethyl (2,2-dicyano-1-[3-methoxy-4-(epoxypropoxy)phenyl]ethyl)phosphonate (EVPM) prepared in S3 of Example 1 was weighed and mixed with 113.36g of bisphenol A type epoxy resin (E51) at 90°C until homogeneous. 36.64g of DDM curing agent was added, and the mixture was stirred until homogeneous. After vacuum degassing at room temperature for 30 minutes, the mixture was poured into a mold and placed in an oven at 100°C for 2 hours, 140°C for 2 hours, 160°C for 2 hours, and 200°C for 2 hours, for a total curing time of eight hours. The resulting epoxy resin composition was named 10EVM-EP / DDM.

[0099] Application Example 2:

[0100] 24g of diethyl (2,2-dicyano-1-[3-methoxy-4-(epoxypropoxy)phenyl]ethyl)phosphonate (EVPM) prepared in S3 of Example 1 was weighed and mixed with 106.18g of bisphenol A type epoxy resin (E51) at 90°C until homogeneous. 29.82g of DDM curing agent was added, and the mixture was stirred until homogeneous. After vacuum degassing at room temperature for 30 minutes, the mixture was poured into a mold and placed in an oven at 100°C for 2 hours, 140°C for 2 hours, 160°C for 2 hours, and 200°C for 2 hours, for a total curing time of eight hours. The resulting epoxy resin composition was named 15EVM-EP / DDM.

[0101] Application Example 3:

[0102] Weigh 32g of diethyl (2,2-dicyano-1-[3-methoxy-4-(epoxypropoxy)phenyl]ethyl)phosphonate (EVPM) prepared in S3 of Example 1, and mix it with 99g of bisphenol A type epoxy resin (E51) at 90°C until homogeneous. Add 29g of DDM curing agent, stir until homogeneous, and then degas under vacuum at room temperature for 30min. Pour the mixture into a mold and place it in an oven at 100°C / 2h, 140°C / 2h, 160°C / 2h, and 200°C / 2h for a total curing time of eight hours. The resulting epoxy resin composition is named 20EVM-EP / DDM.

[0103] Application Example 4:

[0104] 16g of diethyl[1-(3,4-bis(epoxypropane-2-ylmethoxy)phenyl]-2,2-dicyanethylphosphonate (PEPM) prepared in S3 of Example 2 was weighed and mixed with 112.04g of bisphenol A type epoxy resin (E51) at 90°C until homogeneous. 31.97g of DDM curing agent was added, and the mixture was stirred until homogeneous. After vacuum degassing at room temperature for 30min, the mixture was poured into a mold and placed in an oven at 100°C / 2h, 140°C / 2h, 160°C / 2h, and 200°C / 2h for a total curing time of eight hours. The resulting epoxy resin composition was named 10PEPM-EP / DDM.

[0105] Application Example 5:

[0106] 24g of diethyl[1-(3,4-bis(epoxypropane-2-ylmethoxy)phenyl]-2,2-dicyanethylphosphonate (PEPM) prepared in S3 of Example 2 was weighed and mixed with 104.2g of bisphenol A type epoxy resin (E51) at 90°C until homogeneous. 31.8g of DDM curing agent was added, and the mixture was stirred until homogeneous. After vacuum degassing at room temperature for 30min, the mixture was poured into a mold and placed in an oven at 100°C / 2h, 140°C / 2h, 160°C / 2h, and 200°C / 2h for a total curing time of eight hours. The resulting epoxy resin composition was named 15PEPM-EP / DDM.

[0107] Application Example 6:

[0108] Weigh 32g of diethyl[1-(3,4-bis(epoxypropane-2-ylmethoxy)phenyl]-2,2-dicyanethylphosphonate (PEPM) prepared in S3 of Example 2, and mix it with 96.37g of bisphenol A type epoxy resin (E51) at 90°C until homogeneous. Add 31.63g of DDM curing agent, stir until homogeneous, and then degas under vacuum at room temperature for 30min. Pour the mixture into a mold and place it in an oven at 100°C / 2h, 140°C / 2h, 160°C / 2h, and 200°C / 2h for a total curing time of eight hours. The resulting epoxy resin composition is named 20PEPM-EP / DDM.

[0109] Application Example 7:

[0110] 16g of diethyl (2,2-dicyano-1-[3-methoxy-4-(epoxypropoxy)phenyl]ethyl)phosphonate (DEPM) prepared in S3 of Example 3 was weighed and mixed with 112.99g of bisphenol A type epoxy resin (E51) at 90°C until homogeneous. 31.01g of DDM curing agent was added, and the mixture was stirred until homogeneous. After vacuum degassing at room temperature for 30 minutes, the mixture was poured into a mold and placed in an oven at 100°C for 2 hours, 140°C for 2 hours, 160°C for 2 hours, and 200°C for 2 hours, for a total curing time of eight hours. The resulting epoxy resin composition was named 10DEPM-EP / DDM.

[0111] Application Example 8:

[0112] 24g of diethyl (2,2-dicyano-1-[3-methoxy-4-(epoxypropoxy)phenyl]ethyl)phosphonate (DEPM) prepared in S3 of Example 3 was weighed and mixed with 105.63g of bisphenol A type epoxy resin (E51) at 90°C until homogeneous. 30.37g of DDM curing agent was added, and the mixture was stirred until homogeneous. After vacuum degassing at room temperature for 30 minutes, the mixture was poured into a mold and placed in an oven at 100°C for 2 hours, 140°C for 2 hours, 160°C for 2 hours, and 200°C for 2 hours, for a total curing time of eight hours. The resulting epoxy resin composition was named 15DEPM-EP / DDM.

[0113] Application Example 9:

[0114] 32g of diethyl (2,2-dicyano-1-[3-methoxy-4-(epoxypropoxy)phenyl]ethyl)phosphonate (DEPM) prepared in S3 of Example 3 was weighed and mixed with 98.28g of bisphenol A type epoxy resin (E51) at 90°C until homogeneous. 29.72g of DDM curing agent was added, and the mixture was stirred until homogeneous. After vacuum degassing at room temperature for 30 minutes, the mixture was poured into a mold and placed in an oven at 100°C for 2 hours, 140°C for 2 hours, 160°C for 2 hours, and 200°C for 2 hours, for a total curing time of eight hours. The resulting epoxy resin composition was named 20DEPM-EP / DDM.

[0115] Application Example 10: 16g of hexaethyl tetraphosphate ((2,4,6-tris(ethylene oxide-2-ylmethoxy))benzene-1,3,5-triyl)tris(phosphonate) (TEPM) prepared in S3 of Example 4 was weighed and mixed with 112.91g of bisphenol A type epoxy resin (E51) at 90°C until homogeneous. 31.09g of DDM curing agent was added, and the mixture was stirred until homogeneous. After vacuum degassing at room temperature for 30min, the mixture was poured into a mold and placed in an oven at 100°C / 2h, 140°C / 2h, 160°C / 2h, and 200°C / 2h for a total curing time of eight hours. The resulting epoxy resin composition was named 10TEPM-EP / DDM.

[0116] Application Example 11: 24g of hexaethyl tetraphosphate ((2,4,6-tris(ethylene oxide-2-ylmethoxy))benzene-1,3,5-triyl)tris(phosphonate) (TEPM) prepared in S3 of Example 4 was weighed and mixed with 105.51g of bisphenol A type epoxy resin (E51) at 90°C until homogeneous. 30.49g of DDM curing agent was added, and the mixture was stirred until homogeneous. After vacuum degassing at room temperature for 30 minutes, the mixture was poured into a mold and placed in an oven at 100°C for 2 hours, 140°C for 2 hours, 160°C for 2 hours, and 200°C for 2 hours, for a total curing time of eight hours. The resulting epoxy resin composition was named 15TEPM-EP / DDM.

[0117] Application Example 12: 32g of hexaethyl tetraphosphate ((2,4,6-tris(ethylene oxide-2-ylmethoxy))benzene-1,3,5-triyl)tris(phosphonate) (TEPM) prepared in S3 of Example 4 was weighed and mixed with 98.11g of bisphenol A type epoxy resin (E51) at 90°C until homogeneous. 29.89g of DDM curing agent was added, and the mixture was stirred until homogeneous. After vacuum degassing at room temperature for 30 minutes, the mixture was poured into a mold and placed in an oven at 100°C for 2 hours, 140°C for 2 hours, 160°C for 2 hours, and 200°C for 2 hours, for a total curing time of eight hours. The resulting epoxy resin composition was named 20TEPM-EP / DDM.

[0118] Blank application example: Take 127.71g of bisphenol A type epoxy resin (E51), stir evenly at 90℃, add 32.29g of DDM curing agent, and degas under vacuum at room temperature for 30min. Pour into a mold and place in an oven at 100℃ / 2h, 140℃ / 2h, 160℃ / 2h, and 200℃ / 2h for a total of eight hours to obtain DDM-cured E51 epoxy resin, named EP / DDM.

[0119] Table 1 shows the test results for Application Examples 1-12 and the blank application example.

[0120]

[0121]

[0122] As shown in Table 1, the epoxy resin composition obtained by adding the cyanophosphate derivatives prepared in the embodiments of the present invention to the epoxy resin showed an improvement in UL 94 rating from no rating to V0-1 compared with pure epoxy resin without flame retardant (blank application example).

[0123] The LOI value increases with the amount of cyanophosphate derivatives added. At a 20wt% addition of cyanophosphate derivatives, the LOI can reach a maximum of 36.4%.

[0124] The char residue at 800℃ also increased with the addition of cyanophosphate derivatives. With an addition of 20wt% cyanophosphate derivatives, the char residue at 800℃ could reach a maximum of 32.3wt%, indicating that the addition of cyanophosphate derivatives effectively promoted char formation and enhanced the protective layer effect at high temperatures.

[0125] Meanwhile, the tensile strength and impact strength of the epoxy resin composition after adding the cyanophosphate derivatives prepared in the embodiments of the present invention decreased slightly, but it still maintained a high degree of mechanical property retention.

[0126] In summary, the cyanophosphate derivatives provided by this invention have significant flame retardant properties and char-forming ability, while also maintaining good mechanical properties.

[0127] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A cyanophosphate derivative, characterized in that, Its molecular structure can be any of the following: In this context, R1, R2, R3, and R4 represent groups containing aromatic structures, and T represents groups containing phosphate esters.

2. The cyanophosphate derivative according to claim 1, characterized in that, R1 is selected from any of the following structures. R2 is selected from any of the following structures. R3 is selected from any of the following structures. R4 is selected from any of the following structures. The phosphate-containing group is selected from any of the following structures.

3. The method for preparing a cyanophosphate derivative according to claim 1, characterized in that, It has the following steps: S1: An aromatic compound containing hydroxyl and aldehyde groups undergoes a substitution reaction with epichlorohydrin under phase catalyst I. An alkaline solution is added to obtain intermediate I. S2: Intermediate I is dissolved in organic solvent I, and in phase catalyst II, it undergoes a condensation reaction with malononitrile to generate intermediate II; S3: Intermediate II and phosphate ester compounds undergo an addition reaction in phase catalyst III to generate the target product, namely the above-mentioned cyanophosphate ester derivative.

4. The method for preparing a cyanophosphate derivative according to claim 3, characterized in that, In S1, the phase catalyst I is selected from at least one of tetrabutylammonium bromide, benzyltriethylammonium chloride, hexadecyltrimethylammonium bromide, and trioctylmethylammonium chloride; the alkaline solution is selected from NaOH solution; the molar ratio of the aromatic compound containing hydroxyl and aldehyde groups, epichlorohydrin, phase catalyst I and NaOH is 1:(1-20):(0.1-1):(1-12); the temperature of the substitution reaction is 25-100℃, under a nitrogen atmosphere, and the reaction time is 15-24h.

5. The method for preparing a cyanophosphate derivative according to claim 3, characterized in that, In S2, the organic solvent I is selected from at least one of anhydrous ethanol, methanol, isopropanol, cyclohexane, dichloromethane, N,N-dimethylformamide, dimethyl sulfoxide, and pyridine; the phase catalyst II is selected from at least one of potassium carbonate, sodium carbonate, 2-ethyl-4-methylimidazolium, 2-methylimidazolium, 1-methylimidazolium, piperidine, potassium sorbate, potassium alum, ammonium acetate, benzyltriethylammonium chloride, 1-butyl-3-methylimidazolium bromide, triethylamine, and copper sulfate; the molar ratio of intermediate I, malononitrile, and phase catalyst II is 1:(1-4):(0.05-0.3); the condensation reaction is carried out at a temperature of 25-60°C under a nitrogen atmosphere for a reaction time of 2-4 hours.

6. The method for preparing a cyanophosphate derivative according to claim 3, characterized in that, In S3, the phosphate ester compound is selected from at least one of triethyl phosphite, trimethyl phosphite, diethyl phosphite, dimethyl phosphite, diphenyl phosphite, triphenyl phosphite, and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide; the phase catalyst III is selected from at least one of perchloric acid, dodecylmolybdic acid, phosphomolybdic acid, molybdenum phosphate, dodecyltungstic acid, phosphotungstic acid, tungstic acid, dodecyltungstic silica, silicotungstic acid, and ammonium dodecylmolybdic acid; the molar ratio of intermediate II, phosphate ester compound, and phase catalyst III is 1:(1-15):(0.01-0.12); the addition reaction temperature is 25-80°C, under a nitrogen atmosphere, and the reaction time is 1-4 h.

7. The application of a cyanophosphate derivative according to any one of claims 1 or 2, characterized in that, Used to prepare epoxy resin compositions.

8. An epoxy resin composition, characterized in that, Includes a cyanophosphate derivative and an epoxy resin as described in any one of claims 1 or 2.

9. The epoxy resin composition according to claim 8, characterized in that, It also includes a curing agent; the mass ratio of the cyanophosphate derivative, epoxy resin monomer and curing agent is (1-20):(10-20):(1-10).

10. A method for preparing an epoxy resin composition according to claim 8, characterized in that, Mix all components thoroughly and cure at 100–200°C for 4–10 hours.

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