Flame-retardant heat-resistant epoxy resin material and preparation method thereof

Abstract

The invention provides a flame-retardant heat-resistant epoxy resin material and a preparation method thereof, and belongs to the technical field of high polymer materials. The preparation method comprises the following steps: sequentially stirring and mixing bisphenol A epoxy resin, a modified flame retardant and a modified curing agent according to a weight ratio of (95-105): (12-16): (20-25) at 120-150 DEG C, and carrying out vacuum defoaming to obtain a mixture; and treating the mixture at 100-120 DEG C for 2-3 hours, heating to 150-180 DEG C, and treating for 2-3 hours to obtain the flame-retardant heat-resistant epoxy resin material. According to the epoxy resin material provided by the invention, through phosphorus-silicon-nitrogen synergistic flame retardance, condensed-phase flame retardance is combined with gas-phase flame retardance, so that the flame retardance of the epoxy resin material is improved; by constructing a three-dimensional network structure and introducing Si-O bonds, benzene rings and other structures with good stability, molecular chain movement is limited, and the heat resistance of the epoxy resin material is improved; by introducing large-volume groups into the modified curing agent and controlling the crosslinking density, the insulating property of the modified curing agent in a high-temperature environment is ensured.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of high polymer materials, and in particular to a flame-retardant heat-resistant epoxy resin material and a preparation method thereof. BACKGROUND

[0002] Epoxy resin refers to a high polymer prepolymer containing two or more epoxy groups in the molecule. Due to excellent mechanical properties, excellent bonding properties, good heat resistance and corrosion resistance, it is widely used in the fields of automobiles, buildings, electrical appliances, aerospace, etc. However, with the rapid development of new energy equipment, high-voltage electrical equipment and other fields, the traditional epoxy resin material has been difficult to meet the requirements of extreme working conditions in terms of flame retardation, thermal stability and high-temperature insulation.

[0003] Epoxy resin itself is a flammable material, which releases a large amount of heat, smoke and toxic gases when burning, and is extremely easy to cause fire accidents and secondary damage. At present, halogen-based flame retardants have been widely used due to their high flame retardant efficiency, but the hydrogen halide gas produced during combustion has strong corrosive and toxic properties, which does not meet the environmental protection concept. Although phosphorus-based and nitrogen-based flame retardants are relatively environmentally friendly, their flame-retardant effect is limited when used alone, and it is difficult to meet strict flame-retardant standards. The molecular chain of epoxy resin is prone to thermal motion at high temperatures, resulting in a decrease in mechanical properties and poor dimensional stability of the material, which cannot meet the requirements for use in high-temperature environments. To improve the heat resistance of epoxy resin, the molecular structure needs to be changed, heat-resistant groups need to be introduced, or a special network structure needs to be formed to limit the thermal motion of the molecular chain and enhance the thermal stability of the material. In a high-temperature high-voltage electric field environment, the charge transfer between epoxy resin molecules will affect its insulation performance, and the high-temperature environment will exacerbate the movement of the molecular chain, resulting in a decrease in insulation performance.

[0004] Patent CN 108587068A discloses a hydrophobic flame-retardant epoxy resin and a preparation method thereof. The method uses hydroxyl silicone oil as a hydrophobic agent, and graphene and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) as a flame retardant. The hydroxyl silicone oil, graphene and DOPO type epoxy resin are connected by chemical bonding, and then cured to obtain a hydrophobic flame-retardant epoxy resin. The epoxy resin of the invention has the characteristics of non-toxicity, environmental protection and flame retardation, and can be used in harsh outdoor or humid environments, but its heat resistance has not been improved, and its insulation in high-temperature environments has not been discussed.

[0005] Therefore, it is an important problem to be solved in the field to provide an epoxy resin material with good flame-retardant properties and heat resistance, and good insulation in high-temperature environments. SUMMARY

[0006] In order to solve the problems in the prior art, the present application provides a flame-retardant heat-resistant epoxy resin material and a preparation method thereof, and specifically, the technical scheme of the present application includes the following contents.

[0007] A preparation method of a flame-retardant heat-resistant epoxy resin material, the preparation method including the following steps:

[0008] The bisphenol A type epoxy resin, the modified flame retardant and the modified curing agent are mixed by stirring and vacuum degassing at 120-150 DEG C in the weight ratio of 95-105:12-16:20-25 to obtain a mixture;

[0009] After the mixture is treated at 100-120 DEG C for 2-3 hours, the temperature is increased to 150-180 DEG C for 2-3 hours to obtain the flame-retardant heat-resistant epoxy resin material.

[0010] Further, the preparation method of the modified flame retardant includes the following steps:

[0011] The hydroxybenzoic acid and the absolute ethanol are reacted at 70-80 DEG C for 5-6 hours to obtain a hydroxybenzoic acid ester in the weight ratio of 3-4:1-1.5;

[0012] The hydroxybenzoic acid ester and the hydrazine hydrate are reacted at 80-90 DEG C for 5-7 hours to obtain a hydroxybenzoyl hydrazine in the weight ratio of 3.5-5.5:1.2-1.8;

[0013] The aminosilane A and the hydroxybenzoyl hydrazine are reacted at 80-90 DEG C for 4-6 hours to obtain a hydrazide amino silane in the weight ratio of 1.3-2.1:0.9-1.7;

[0014] The hydrazide amino silane, the aminosilane B, the phosphoric acid compound and the formaldehyde are reacted at 80-85 DEG C for 12-16 hours to obtain the modified flame retardant in the weight ratio of 2.9-3.3:3.4-4.5:2.8-3.5:0.8-1.

[0015] Further, the hydroxybenzoic acid includes one of p-hydroxybenzoic acid or m-hydroxybenzoic acid.

[0016] Further, the aminosilane A is 3-aminopropyl triethoxysilane.

[0017] Further, the aminosilane B is 3-aminopropyl triethoxysilane.

[0018] Further, the phosphoric acid compound is phytic acid.

[0019] Further, the preparation method of the modified curing agent includes the following steps:

[0020] 2-aminothiophenol, sodium nitrite and hydrochloric acid are reacted at 0-5 DEG C for 60-80 min to obtain a mixed system, then furfuraldehyde and a first catalyst are added and reacted at 23-25 DEG C for 4-6 h to obtain an intermediate;

[0021] dichloromethylvinylsilane, the intermediate and a second catalyst are reacted at 65-75 DEG C for 24-28 h to obtain an aldehyde furan silane;

[0022] the aldehyde furan silane, phenylenediamine and a third catalyst are reacted at 24-26 DEG C for 24-30 h to obtain the modified curing agent.

[0023] Further, the first catalyst is copper chloride.

[0024] Further, the weight ratio of 2-aminothiophenol, sodium nitrite, hydrochloric acid, furfuraldehyde and the first catalyst is 2.1-2.4:1.5-1.8:4.5-6.5:0.9-1.2:0.045-0.055.

[0025] Further, the second catalyst is azobisisobutyronitrile.

[0026] Further, the weight ratio of dichloromethylvinylsilane, the intermediate and the second catalyst is 10-12:9-11:0.38-0.46.

[0027] Further, the phenylenediamine comprises one of p-phenylenediamine or m-phenylenediamine.

[0028] Further, the third catalyst is triethylamine.

[0029] Further, the stirring mixing time is 30-45 min.

[0030] Further, the vacuum defoaming time is 5-10 min.

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

[0032] (1) In the present application, the carboxyl group of hydroxybenzoic acid is esterified with the hydroxyl group of anhydrous ethanol to obtain hydroxybenzoic acid ester, the formic acid ester of hydroxybenzoic acid ester is hydrazidated with hydrazine hydrate to obtain hydroxybenzoyl hydrazine, and the hydroxybenzoyl hydrazine is silylated with aminosilane to obtain hydrazide amino silane; the amino group of hydrazide amino silane, the amino group of aminosilane, the phosphoric acid group of a phosphoric acid compound, and formaldehyde are reacted to modify the amino groups of hydrazide amino silane and aminosilane to the phosphoric acid compound to obtain a modified flame retardant; 2-aminobenzenethiol is reacted with sodium nitrite and hydrochloric acid to obtain a mixed system containing a diazonium salt, the diazonium salt in the mixed system is reacted with the furan ring of furfural to obtain an intermediate, the olefin of dichloromethylvinylsilane is reacted with the thiol of the intermediate to obtain aldehyde furan silane, and the chlorine atom of aldehyde furan silane is reacted with the amino group of phenylenediamine to obtain a modified curing agent; the hydrazide group of the modified flame retardant and the aldehyde group of the modified curing agent can form an acylhydrazone bond in the curing process, the amino group in the modified curing agent is reacted with the epoxy group in the epoxy resin to form a three-dimensional network to prepare a flame-retardant heat-resistant epoxy resin material.

[0033] (2) The flame-retardant heat-resistant epoxy resin material prepared in the present application has a phosphorus-silicon-nitrogen synergistic flame-retardant effect, the phosphoric acid group provides phosphorus elements, promotes the carbonization of the epoxy resin at high temperatures to form a dense carbon layer, the silane component is condensed at high temperatures to form a silica inorganic network, an organic carbon-inorganic silicon double-layer barrier is formed, condensed phase flame retardation is achieved, the hydrazide group and the amino group can provide nitrogen elements, release inert gas to dilute combustible gas during decomposition, and gas phase flame retardation is achieved, and the two flame-retardant methods are synergistic to improve the flame-retardant performance of the epoxy resin material.

[0034] (3) The three-dimensional network structure formed in the present application can limit molecular chain movement, so that the flame-retardant heat-resistant epoxy resin material has good heat resistance; in addition, the flame-retardant heat-resistant epoxy resin material contains rich Si-O bonds, Si-C bonds and Si-N bonds, which have good stability, the benzene rings and pyran rings are interlaced with each other, further limiting the thermal movement of the molecular chain, and the above-mentioned effects are synergistic to improve the heat resistance of the flame-retardant heat-resistant epoxy resin material.

[0035] (4) In the present application, bulky groups such as benzene rings and furan rings are introduced into the modified curing agent, which produces steric hindrance in an electric field environment, prevents molecular stacking, and thus inhibits charge transfer between molecules; in addition, the crosslinking of the epoxy group and the amino group in the flame-retardant heat-resistant epoxy resin material and the crosslinking of the hydrazide group and the aldehyde group form a multiple crosslinking network, which further limits charge transfer, so that the flame-retardant heat-resistant epoxy resin material has good insulation performance; the Si-O structure and high crosslinking density in the flame-retardant heat-resistant epoxy resin material enable it to maintain good insulation performance in a high-temperature environment. DETAILED DESCRIPTION

[0036] The technical solutions of the present application will be described clearly and completely below through the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all the other embodiments obtained by those skilled in the art without creative work belong to the scope of protection of the present application.

[0037] Unless otherwise specified, the raw materials and reagents used in the present application below are commercially available or can be prepared by known methods.

[0038] Preparation Example 1

[0039] The preparation method of the modified flame retardant comprises the following steps:

[0040] After 30 parts by weight of p-hydroxybenzoic acid and 10 parts by weight of anhydrous ethanol are stirred and mixed, the pH is adjusted to 1, and after stirring and reacting at 70°C for 5 hours, it is cooled to 23°C, poured into ice water, and the pH is adjusted to 7, and then extracted and dried in sequence to obtain hydroxybenzoic acid ester; 35 parts by weight of hydroxybenzoic acid ester and 12 parts by weight of hydrazine hydrate are dispersed in 500 parts by weight of anhydrous ethanol, and stirred and reacted at 80°C for 5 hours, and then filtered and recrystallized in sequence to obtain hydroxybenzoyl hydrazine; 13 parts by weight of 3-aminopropyl triethoxysilane and 9 parts by weight of hydroxybenzoyl hydrazine are dispersed in 500 parts by weight of a mixed solvent (V 无水乙醇 :V 去离子水 = 3:1), and stirred and reacted at 80°C for 4 hours, and then washed, filtered, and vacuum dried in sequence to obtain hydrazide amino silane; 29 parts by weight of hydrazide amino silane, 34 parts by weight of 3-aminopropyl triethoxysilane, 28 parts by weight of phytic acid, and 8 parts by weight of formaldehyde are dispersed in 1000 parts by weight of a mixed solvent (V 无水乙醇 :V 去离子水 = 3:1), and stirred and reacted at 80°C for 12 hours under a nitrogen atmosphere to obtain the modified flame retardant.

[0041] Preparation Example 2

[0042] The preparation method of the modified flame retardant comprises the following steps:

[0043] After 32 parts by weight of p-hydroxybenzoic acid and 11 parts by weight of anhydrous ethanol are stirred and mixed, the pH is adjusted to 1.5, and after stirring and reacting at 72°C for 5.2 hours, it is cooled to 24°C, poured into ice water, and the pH is adjusted to 7.4, and then extracted and dried in sequence to obtain hydroxybenzoic acid ester; 40 parts by weight of hydroxybenzoic acid ester and 14 parts by weight of hydrazine hydrate are dispersed in 500 parts by weight of anhydrous ethanol, and stirred and reacted at 82°C for 5.5 hours, and then filtered and recrystallized in sequence to obtain hydroxybenzoyl hydrazine; 15 parts by weight of 3-aminopropyl triethoxysilane and 11 parts by weight of hydroxybenzoyl hydrazine are dispersed in 500 parts by weight of a mixed solvent (V 无水乙醇 :V去离子水 = 3: 1) at 82°C for 4.5 h, and after the reaction was completed, the hydrazide amino silane was obtained by washing, suction filtration and vacuum drying in sequence; 30 parts by weight of the hydrazide amino silane, 36 parts by weight of 3-aminopropyl triethoxysilane, 30 parts by weight of phytic acid and 10 parts by weight of formaldehyde were dispersed in 1000 parts by weight of a mixed solvent (V 无水乙醇 : V 去离子水 = 3: 1) at 81°C for 13 h under nitrogen protection to obtain the modified flame retardant.

[0044] Preparation Example 3:

[0045] The method for preparing the modified flame retardant comprises the following steps:

[0046] After 37 parts by weight of m-hydroxybenzoic acid and 13 parts by weight of anhydrous ethanol were stirred and mixed, the pH was adjusted to 2, and after stirring and reacting at 80°C for 6 h, it was cooled to 24°C, poured into ice water and the pH was adjusted to 7, and then extracted and dried in sequence to obtain the hydroxybenzoate; 50 parts by weight of the hydroxybenzoate and 16 parts by weight of hydrazine hydrate were dispersed in 500 parts by weight of anhydrous ethanol, and after stirring and reacting at 90°C for 7 h, the hydroxybenzoyl hydrazine was obtained by suction filtration and recrystallization in sequence; 18 parts by weight of 3-aminopropyl triethoxysilane and 15 parts by weight of the hydroxybenzoyl hydrazine were dispersed in 500 parts by weight of a mixed solvent (V 无水乙醇 : V 去离子水 = 3: 1) at 85°C for 5 h, and after the reaction was completed, the hydrazide amino silane was obtained by washing, suction filtration and vacuum drying in sequence; 31 parts by weight of the hydrazide amino silane, 38 parts by weight of 3-aminopropyl triethoxysilane, 32 parts by weight of phytic acid and 12 parts by weight of formaldehyde were dispersed in 1000 parts by weight of a mixed solvent (V 无水乙醇 : V 去离子水 = 3: 1) at 82°C for 14 h under nitrogen protection to obtain the modified flame retardant.

[0047] Preparation Example 4:

[0048] The method for preparing the modified flame retardant comprises the following steps:

[0049] After 37 parts by weight of m-hydroxybenzoic acid and 13 parts by weight of anhydrous ethanol were stirred and mixed, the pH was adjusted to 2, and after stirring and reacting at 80°C for 6 h, it was cooled to 24°C, poured into ice water and the pH was adjusted to 7, and then extracted and dried in sequence to obtain the hydroxybenzoate; 50 parts by weight of the hydroxybenzoate and 16 parts by weight of hydrazine hydrate were dispersed in 500 parts by weight of anhydrous ethanol, and after stirring and reacting at 90°C for 7 h, the hydroxybenzoyl hydrazine was obtained by suction filtration and recrystallization in sequence; 18 parts by weight of 3-aminopropyl triethoxysilane and 15 parts by weight of the hydroxybenzoyl hydrazine were dispersed in 500 parts by weight of a mixed solvent (V 无水乙醇 : V去离子水 = 3: 1) at 90°C for 6h, and then the hydrazide amino silane was obtained by washing, filtration and vacuum drying in sequence after the reaction was completed; 32 parts by weight of the hydrazide amino silane, 42 parts by weight of 3-aminopropyl triethoxysilane, 33 parts by weight of phytic acid and 12 parts by weight of formaldehyde were dispersed in 1000 parts by weight of the mixed solvent (V 无水乙醇 : V 去离子水 = 3: 1) at 90°C for 6h, and then the hydrazide amino silane was obtained by washing, filtration and vacuum drying in sequence after the reaction was completed; 32 parts by weight of the hydrazide amino silane, 42 parts by weight of 3-aminopropyl triethoxysilane, 33 parts by weight of phytic acid and 12 parts by weight of formaldehyde were dispersed in 1000 parts by weight of the mixed solvent (V

[0050] Preparation Example 5:

[0051] The preparation method of the modified flame retardant comprises the following steps:

[0052] After 40 parts by weight of p-hydroxybenzoic acid and 15 parts by weight of anhydrous ethanol were stirred and mixed, the pH was adjusted to 3, and after stirring and reacting at 80°C for 6h, it was cooled to 25°C, poured into ice water and adjusted to a pH of 8, and then extracted and dried in sequence to obtain hydroxybenzoic acid ester; 55 parts by weight of the hydroxybenzoic acid ester and 18 parts by weight of hydrazine hydrate were dispersed in 500 parts by weight of anhydrous ethanol, and after stirring and reacting at 90°C for 7h, the hydrazine carboxybenzoic acid was obtained by filtration and recrystallization in sequence after the reaction was completed; 21 parts by weight of 3-aminopropyl triethoxysilane and 17 parts by weight of hydrazine carboxybenzoic acid were dispersed in 500 parts by weight of the mixed solvent (V 无水乙醇 : V 去离子水 = 3: 1) at 90°C for 6h, and then the hydrazide amino silane was obtained by washing, filtration and vacuum drying in sequence after the reaction was completed; 32 parts by weight of the hydrazide amino silane, 42 parts by weight of 3-aminopropyl triethoxysilane, 33 parts by weight of phytic acid and 12 parts by weight of formaldehyde were dispersed in 1000 parts by weight of the mixed solvent (V 无水乙醇 : V 去离子水 = 3: 1) at 90°C for 6h, and then the hydrazide amino silane was obtained by washing, filtration and vacuum drying in sequence after the reaction was completed; 32 parts by weight of the hydrazide amino silane, 42 parts by weight of 3-aminopropyl triethoxysilane, 33 parts by weight of phytic acid and 12 parts by weight of formaldehyde were dispersed in 1000 parts by weight of the mixed solvent (V

[0053] Preparation Example 6:

[0054] The preparation method of the modified flame retardant comprises the following steps:

[0055] 78 parts by weight of 3-aminopropyl triethoxysilane, 35 parts by weight of phytic acid and 15 parts by weight of formaldehyde were dispersed in 1000 parts by weight of the mixed solvent (V 无水乙醇 : V 去离子水 = 3: 1) at 90°C for 6h, and then the hydrazide amino silane was obtained by washing, filtration and vacuum drying in sequence after the reaction was completed; 32 parts by weight of the hydrazide amino silane, 42 parts by weight of 3-aminopropyl triethoxysilane, 33 parts by weight of phytic acid and 12 parts by weight of formaldehyde were dispersed in 1000 parts by weight of the mixed solvent (V

[0056] Preparation Example 7:

[0057] The preparation method of the modified flame retardant comprises the following steps:

[0058] Preparation Example 5 was replaced with 21 parts by weight of N-methyl-3- aminopropyltrimethoxysilane, and the other operations were the same as those in Preparation Example 7.

[0059] Preparation Example 8:

[0060] A method for preparing a modified curing agent, comprising the steps of:

[0061] 21 parts by weight of 2-aminobenzenethiol, 15 parts by weight of sodium nitrite and 45 parts by weight of hydrochloric acid were dispersed in 500 parts by weight of deionized water, and stirred at 0°C for 60 min to obtain a mixed system, then 9 parts by weight of furfuraldehyde, 0.45 parts by weight of copper chloride and 100 parts by weight of deionized water were added, and stirred at 23°C for 4 h, after the reaction was completed, the intermediate was obtained by distillation, suction filtration and recrystallization in sequence; 10 parts by weight of dichloromethylvinylsilane, 9 parts by weight of the intermediate and 0.38 parts by weight of azobisisobutyronitrile were dispersed in 50 parts by weight of tetrahydrofuran, and stirred at 65°C for 24 h in a nitrogen protection environment, after the reaction was completed, the temperature was cooled to room temperature, washed with deionized water and collected by filtration, and vacuum dried at 50°C to obtain aldehyde furan silane; 20 parts by weight of aldehyde furan silane, 18 parts by weight of p-phenylenediamine and 15 parts by weight of triethylamine were dispersed in 100 parts by weight of anhydrous ether, and stirred at 24°C for 24 h in a nitrogen protection environment, after the reaction was completed, the modified curing agent was obtained by vacuum filtration and recrystallization in sequence.

[0062] Preparation Example 9:

[0063] A method for preparing a modified curing agent, comprising the steps of:

[0064] 22 parts by weight of 2-aminobenzenethiol, 16 parts by weight of sodium nitrite and 52 parts by weight of hydrochloric acid were dispersed in 500 parts by weight of deionized water, and stirred at 2°C for 65 min to obtain a mixed system, then 10 parts by weight of furfuraldehyde, 0.47 parts by weight of copper chloride and 100 parts by weight of deionized water were added, and stirred at 24°C for 4.5 h, after the reaction was completed, the intermediate was obtained by distillation, suction filtration and recrystallization in sequence; 10.5 parts by weight of dichloromethylvinylsilane, 9.5 parts by weight of the intermediate and 0.40 parts by weight of azobisisobutyronitrile were dispersed in 50 parts by weight of tetrahydrofuran, and stirred at 67°C for 25 h in a nitrogen protection environment, after the reaction was completed, the temperature was cooled to room temperature, washed with deionized water and collected by filtration, and vacuum dried at 50°C to obtain aldehyde furan silane; 21 parts by weight of aldehyde furan silane, 18.5 parts by weight of p-phenylenediamine and 15.5 parts by weight of triethylamine were dispersed in 100 parts by weight of anhydrous ether, and stirred at 25°C for 26 h in a nitrogen protection environment, after the reaction was completed, the modified curing agent was obtained by vacuum filtration and recrystallization in sequence.

[0065] Preparation Example 10:

[0066] A method for preparing a modified curing agent, comprising the steps of:

[0067] 23 parts by weight of 2-aminobenzenethiol, 16.5 parts by weight of sodium nitrite and 58 parts by weight of hydrochloric acid are dispersed in 500 parts by weight of deionized water, and the mixture is stirred at 3°C for 70 minutes to obtain a reaction system. Then, 10.5 parts by weight of furfuraldehyde, 0.49 parts by weight of copper chloride and 100 parts by weight of deionized water are added, and the mixture is stirred at 24°C for 5 hours. After the reaction is completed, the intermediate is obtained by distillation, filtration and recrystallization in sequence. Then, 11 parts by weight of dichloromethylvinylsilane, 10 parts by weight of the intermediate and 0.42 parts by weight of azobisisobutyronitrile are dispersed in 50 parts by weight of tetrahydrofuran, and the mixture is stirred at 70°C for 26 hours under nitrogen protection. After the reaction is completed, the mixture is cooled to room temperature, washed with deionized water and filtered to collect the product, which is dried at 50°C under vacuum to obtain aldehyde furan silane. Then, 22 parts by weight of the aldehyde furan silane, 19 parts by weight of m-phenylenediamine and 16 parts by weight of triethylamine are dispersed in 100 parts by weight of anhydrous ether, and the mixture is stirred at 26°C for 27 hours under nitrogen protection. After the reaction is completed, the modified curing agent is obtained by filtration under reduced pressure and recrystallization in sequence.

[0068] Preparation Example 11:

[0069] A method for preparing a modified curing agent, comprising the steps of:

[0070] 23.5 parts by weight of 2-aminobenzenethiol, 17 parts by weight of sodium nitrite and 62 parts by weight of hydrochloric acid are dispersed in 500 parts by weight of deionized water, and the mixture is stirred at 4°C for 75 minutes to obtain a reaction system. Then, 11 parts by weight of furfuraldehyde, 0.52 parts by weight of copper chloride and 100 parts by weight of deionized water are added, and the mixture is stirred at 23°C for 5 hours. After the reaction is completed, the intermediate is obtained by distillation, filtration and recrystallization in sequence. Then, 11.5 parts by weight of dichloromethylvinylsilane, 10.5 parts by weight of the intermediate and 0.44 parts by weight of azobisisobutyronitrile are dispersed in 50 parts by weight of tetrahydrofuran, and the mixture is stirred at 72°C for 27 hours under nitrogen protection. After the reaction is completed, the mixture is cooled to room temperature, washed with deionized water and filtered to collect the product, which is dried at 50°C under vacuum to obtain aldehyde furan silane. Then, 23 parts by weight of the aldehyde furan silane, 19.5 parts by weight of m-phenylenediamine and 16 parts by weight of triethylamine are dispersed in 100 parts by weight of anhydrous ether, and the mixture is stirred at 26°C for 28 hours under nitrogen protection. After the reaction is completed, the modified curing agent is obtained by filtration under reduced pressure and recrystallization in sequence.

[0071] Preparation Example 12:

[0072] A method for preparing a modified curing agent, comprising the steps of:

[0073] 24 parts by weight of 2-aminobenzenethiol, 18 parts by weight of sodium nitrite and 65 parts by weight of hydrochloric acid were dispersed in 50 parts by weight of deionized water, and stirred at 5°C for 80 min to obtain a mixed system, then 12 parts by weight of furan carboxaldehyde, 0.55 parts by weight of copper chloride and 100 parts by weight of deionized water were added, and stirred at 25°C for 6 h, after the reaction was completed, the intermediate was obtained by distillation, filtration and recrystallization in sequence; 12 parts by weight of dichloromethylvinylsilane, 11 parts by weight of the intermediate and 0.46 parts by weight of azobisisobutyronitrile were dispersed in 50 parts by weight of tetrahydrofuran, and stirred at 75°C for 28 h in a nitrogen protection environment, after the reaction was completed, the temperature was cooled to room temperature, washed with deionized water and collected by filtration, and dried at 50°C under vacuum to obtain aldehyde furan silane; 24 parts by weight of aldehyde furan silane, 20 parts by weight of p-phenylenediamine and 17 parts by weight of triethylamine were dispersed in 100 parts by weight of anhydrous ether, and stirred at 26°C for 30 h in a nitrogen protection environment, after the reaction was completed, the modified curing agent was obtained by filtration under reduced pressure and recrystallization in sequence.

[0074] Preparation Example 13:

[0075] The preparation method of the modified curing agent comprises the following steps:

[0076] The p-phenylenediamine in Preparation Example 12 is replaced by o-phenylenediamine, and the other operations remain the same as those in Preparation Example 12.

[0077] Preparation Example 14:

[0078] The preparation method of the modified curing agent comprises the following steps:

[0079] 12 parts by weight of dichloromethylvinylsilane, 11 parts by weight of 4-mercaptobenzoic acid and 0.46 parts by weight of azobisisobutyronitrile were dispersed in 50 parts by weight of tetrahydrofuran, and stirred at 75°C for 28 h in a nitrogen protection environment, after the reaction was completed, the temperature was cooled to room temperature, washed with deionized water and collected by filtration, and dried at 50°C under vacuum to obtain aldehyde furan silane; 24 parts by weight of aldehyde furan silane, 20 parts by weight of p-phenylenediamine and 17 parts by weight of triethylamine were dispersed in 100 parts by weight of anhydrous ether, and stirred at 26°C for 30 h in a nitrogen protection environment, after the reaction was completed, the modified curing agent was obtained by filtration under reduced pressure and recrystallization in sequence.

[0080] Preparation Example 15:

[0081] The preparation method of the modified curing agent comprises the following steps:

[0082] 24 parts by weight of methyldichlorosilane, 20 parts by weight of p-phenylenediamine and 17 parts by weight of triethylamine were dispersed in 100 parts by weight of anhydrous ether, and stirred at 26°C for 30 h in a nitrogen protection environment, after the reaction was completed, the modified curing agent was obtained by filtration under reduced pressure and recrystallization in sequence.

[0083] Example 1:

[0084] A method for preparing a flame-retardant heat-resistant epoxy resin material, comprising the steps of:

[0085] After 95 parts by weight of bisphenol A type epoxy resin, 12 parts by weight of the modified flame retardant prepared in Preparation Example 1, 20 parts by weight of the modified curing agent prepared in Preparation Example 8 and 20 parts by weight of acetone are stirred and mixed at 120°C for 30 min, a mixture is obtained by vacuum degassing treatment for 5 min, the mixture is quickly poured into a polytetrafluoroethylene mold, and after curing treatment at 100°C for 2 h, the temperature is raised to 150°C for curing treatment for 2 h to prepare the flame-retardant heat-resistant epoxy resin material.

[0086] Example 2:

[0087] A method for preparing a flame-retardant heat-resistant epoxy resin material, comprising the steps of:

[0088] After 98 parts by weight of bisphenol A type epoxy resin, 13 parts by weight of the modified flame retardant prepared in Preparation Example 2, 21 parts by weight of the modified curing agent prepared in Preparation Example 9 and 25 parts by weight of acetone are stirred and mixed at 125°C for 33 min, a mixture is obtained by vacuum degassing treatment for 6 min, the mixture is quickly poured into a polytetrafluoroethylene mold, and after curing treatment at 105°C for 2.2 h, the temperature is raised to 155°C for curing treatment for 2.2 h to prepare the flame-retardant heat-resistant epoxy resin material.

[0089] Example 3:

[0090] A method for preparing a flame-retardant heat-resistant epoxy resin material, comprising the steps of:

[0091] After 100 parts by weight of bisphenol A type epoxy resin, 14 parts by weight of the modified flame retardant prepared in Preparation Example 3, 22 parts by weight of the modified curing agent prepared in Preparation Example 10 and 30 parts by weight of acetone are stirred and mixed at 130°C for 38 min, a mixture is obtained by vacuum degassing treatment for 7 min, the mixture is quickly poured into a polytetrafluoroethylene mold, and after curing treatment at 110°C for 2.5 h, the temperature is raised to 160°C for curing treatment for 2.5 h to prepare the flame-retardant heat-resistant epoxy resin material.

[0092] Example 4:

[0093] A method for preparing a flame-retardant heat-resistant epoxy resin material, comprising the steps of:

[0094] 102 parts by weight of bisphenol A type epoxy resin, 15 parts by weight of the modified flame retardant prepared in Preparation Example 4, 23 parts by weight of the modified curing agent prepared in Preparation Example 11 and 35 parts by weight of acetone were mixed at 140°C for 42 minutes, and then vacuum degassing treatment was performed for 9 minutes to obtain a mixture. The mixture was quickly poured into a polytetrafluoroethylene mold, and curing treatment was performed at 115°C for 2.7 hours and then at 170°C for 2.5 hours to obtain a flame-retardant heat-resistant epoxy resin material.

[0095] Example 5:

[0096] A method for preparing a flame-retardant heat-resistant epoxy resin material, comprising the steps of:

[0097] 105 parts by weight of bisphenol A type epoxy resin, 16 parts by weight of the modified flame retardant prepared in Preparation Example 5, 25 parts by weight of the modified curing agent prepared in Preparation Example 12 and 40 parts by weight of acetone were mixed at 150°C for 45 minutes, and then vacuum degassing treatment was performed for 10 minutes to obtain a mixture. The mixture was quickly poured into a polytetrafluoroethylene mold, and curing treatment was performed at 120°C for 3 hours and then at 180°C for 3 hours to obtain a flame-retardant heat-resistant epoxy resin material.

[0098] Comparative Example 1:

[0099] A method for preparing a flame-retardant heat-resistant epoxy resin material, comprising the steps of:

[0100] In Example 5, the modified flame retardant prepared in Preparation Example 5 was replaced with the modified flame retardant prepared in Preparation Example 6, and the other operations were the same as those in Example 5.

[0101] Comparative Example 2:

[0102] A method for preparing a flame-retardant heat-resistant epoxy resin material, comprising the steps of:

[0103] In Example 5, the 16 parts by weight of the modified flame retardant prepared in Preparation Example 5 was replaced with 25 parts by weight of the modified flame retardant prepared in Preparation Example 5, and the other operations were the same as those in Example 5.

[0104] Comparative Example 3:

[0105] A method for preparing a flame-retardant heat-resistant epoxy resin material, comprising the steps of:

[0106] In Example 5, the 16 parts by weight of the modified flame retardant prepared in Preparation Example 5 was replaced with 25 parts by weight of the modified flame retardant prepared in Preparation Example 5, and the other operations were the same as those in Example 5.

[0107] Comparative Example 4:

[0108] A method for preparing a flame-retardant heat-resistant epoxy resin material, comprising the steps of:

[0109] Example 5 was removed, and the other operations were kept consistent with Example 5.

[0110] Comparative Example 5:

[0111] A preparation method of a flame-retardant heat-resistant epoxy resin material includes the following steps:

[0112] The modified curing agent prepared in Preparation Example 12 in Example 5 was replaced with the modified curing agent prepared in Preparation Example 13, and the other operations were kept consistent with Example 5.

[0113] Comparative Example 6:

[0114] A preparation method of a flame-retardant heat-resistant epoxy resin material includes the following steps:

[0115] The modified curing agent prepared in Preparation Example 12 in Example 5 was replaced with the modified curing agent prepared in Preparation Example 14, and the other operations were kept consistent with Example 5.

[0116] Comparative Example 7:

[0117] A preparation method of a flame-retardant heat-resistant epoxy resin material includes the following steps:

[0118] The modified curing agent prepared in Preparation Example 12 in Example 5 was replaced with the modified curing agent prepared in Preparation Example 15, and the other operations were kept consistent with Example 5.

[0119] Comparative Example 8:

[0120] A preparation method of a flame-retardant heat-resistant epoxy resin material includes the following steps:

[0121] The modified curing agent prepared in Preparation Example 12 in Example 5 was replaced with the modified curing agent prepared in Preparation Example 12, and the other operations were kept consistent with Example 5.

[0122] Comparative Example 9:

[0123] A preparation method of a flame-retardant heat-resistant epoxy resin material includes the following steps:

[0124] The modified curing agent prepared in Preparation Example 12 in Example 5 was replaced with the modified curing agent prepared in Preparation Example 12, and the other operations were kept consistent with Example 5.

[0125] Comparative Example 10:

[0126] A preparation method of a flame-retardant heat-resistant epoxy resin material includes the following steps:

[0127] The modified curing agent prepared in Preparation Example 12 in Example 5 was replaced with p-phenylenediamine, and other operations were consistent with those in Example 5.

[0128] Performance test:

[0129] Test Example 1: Flame retardant performance test

[0130] Vertical burning test (UL-94): The vertical burning performance of the flame-retardant heat-resistant epoxy resin materials prepared in Examples 1-5 and Comparative Examples 1-10 was tested according to the test method in GB / T 2408-2008;

[0131] Limiting oxygen index test (LOI): The limiting oxygen index of the flame-retardant heat-resistant epoxy resin materials prepared in Examples 1-5 and Comparative Examples 1-10 was tested according to the test method in GB / T 2406-2015;

[0132] The test results are shown in Table 1.

[0133] Table 1. Flame retardant performance test

[0134]

[0135]

[0136] It can be seen from the test data in Table 1 that the flame-retardant heat-resistant epoxy resin materials prepared in Examples 1-5 have good flame retardant performance.

[0137] Test Example 2: Heat resistance

[0138] Glass transition temperature test: The flame-retardant heat-resistant epoxy resin materials prepared in Examples 1-5 and Comparative Examples 1-10 were tested using a DSC214 differential scanning calorimeter, with a sample mass of 5-10 mg, a heating rate of 10°C / min, a nitrogen atmosphere, and a test range of 25-350°C;

[0139] Dielectric constant test: The relative dielectric constant (1 GHz) of the flame-retardant heat-resistant epoxy resin materials prepared in Examples 1-5 and Comparative Examples 1-10 at 25°C and 150°C was tested using a QS87 dielectric loss and dielectric constant measurement system according to the test method in GB / T 1409-2006;

[0140] The test results are shown in Table 2.

[0141] Table 2. Heat resistance test

[0142]

[0143]

[0144] It can be observed from the test results in Table 2 that the flame-retardant heat-resistant epoxy resin materials prepared in Examples 1-5 have good heat resistance and low relative dielectric constant, and can still maintain a low relative dielectric constant at a high temperature of 150°C.

[0145] Test Example 3: Mechanical property test

[0146] Bending strength test: The bending strength of the flame-retardant heat-resistant epoxy resin materials prepared in Examples 1-5 and Comparative Examples 1-10 was tested at 25°C and 150°C using an AGC-J electronic tensile testing machine according to the test method of GB / T 1043-2008, and the test results are shown in Table 3.

[0147] Table 3. Mechanical property test

[0148]

[0149]

[0150] It can be observed from the test results in Table 3 that the flame-retardant heat-resistant epoxy resin materials prepared in Examples 1-5 have good bending strength at 25°C and 150°C, while the bending strength of Examples 1-10 is lower at 25°C and 150°C.

[0151] From the test results in Tables 1, 2 and 3, it can be observed that the structure and amount of the modified flame retardant and the modified curing agent are important for preparing the flame-retardant heat-resistant epoxy resin material. The reason for the performance reduction in Comparative Example 1 and Comparative Example 2 can be that the modified flame retardant and the modified curing agent cannot form an acylhydrazone bond or have a low acylhydrazone bond content, resulting in low compatibility of the modified flame retardant with the epoxy resin material, which in turn leads to a decrease in the performance of the epoxy resin material; in Comparative Example 3, too much modified flame retardant can increase the flame retardant performance, but also adversely affects the mechanical properties of the epoxy resin material; the performance of Comparative Example 5 is lower than that of Example 5, which can be due to the steric structure of the o-phenylenediamine, which produces a large steric hindrance when used as a curing agent, which is not conducive to the curing of the epoxy resin material; the reason for the low performance of Comparative Example 6, Comparative Example 7 and Comparative Example 10 can be that the modified curing agent and p-phenylenediamine as a curing agent can cause molecular stacking, resulting in an increase in the dielectric constant of the epoxy resin material; the reason for the low performance of Comparative Example 8 can be that too little modified curing agent is added, which reduces the crosslinking degree of the epoxy resin material; and the reason for the low performance of Comparative Example 9 can be that too much modified curing agent is added, which affects the mechanical properties of the epoxy resin material.

[0152] The above embodiments describe the technical solutions and beneficial effects of the present application in detail. It should be understood that the above description is only a specific embodiment of the present application and is not intended to limit the present application. Without departing from the spirit and scope of the present application, various changes and improvements can be made to the present application, and these changes and improvements all fall within the scope of the claimed present application.

Claims

1. A method for preparing a flame retardant and heat resistant epoxy resin material, characterized in that: The preparation method comprises the following steps: Bisphenol A epoxy resin, modified flame retardant and modified curing agent are sequentially stirred and mixed at 120-150° C. in a weight ratio of 95-105:12-16:20-25, and vacuum degassed to obtain a mixture; The mixture is treated at 100-120° C. for 2-3 hours, and then heated to 150-180° C. for 2-3 hours to obtain the flame-retardant and heat-resistant epoxy resin material.

2. The method for preparing a flame retardant and heat resistant epoxy resin material according to claim 1, wherein: The preparation method of the modified flame retardant comprises the following steps: Hydroxybenzoic acid and anhydrous ethanol are reacted at a weight ratio of 3-4:1-1.5 at 70-80° C. for 5-6 hours to obtain a hydroxybenzoate; Hydroxybenzoic acid ester and hydrazine hydrate are reacted at a weight ratio of 3.5-5.5:1.2-1.8 at 80-90° C. for 5-7 hours to obtain hydroxybenzoyl hydrazide; Aminosilane A and hydroxybenzoic acid hydrazide are reacted at a weight ratio of 1.3-2.1:0.9-1.7 at 80-90° C. for 4-6 hours to obtain hydrazide aminosilane; The modified flame retardant is prepared by reacting hydrazide aminosilane, aminosilane B, a phosphoric acid compound and formaldehyde in a weight ratio of 2.9-3.3:3.4-4.5:2.8-3.5:0.8-1.5 at 80-85° C. for 12-16 hours.

3. The method for preparing a flame retardant and heat resistant epoxy resin material according to claim 2, wherein: The hydroxybenzoic acid includes one of p-hydroxybenzoic acid and m-hydroxybenzoic acid.

4. The method for preparing a flame retardant and heat resistant epoxy resin material according to claim 2, wherein: The phosphate compound is phytic acid.

5. The method for preparing a flame retardant and heat resistant epoxy resin material according to claim 1, wherein: The preparation method of the modified curing agent comprises the following steps: 2-aminothiophenol, sodium nitrite and hydrochloric acid are reacted at 0-5°C for 60-80 minutes to obtain a mixed system, and furfural and the first catalyst are added and reacted at 23-25°C for 4-6 hours to obtain an intermediate; Dichloromethylvinylsilane, the intermediate and the second catalyst react at 65-75° C. for 24-28 hours to obtain aldehyde furan silane; The modified curing agent is prepared by reacting aldehyde furan silane, phenylenediamine and a third catalyst at 24-26° C. for 24-30 hours.

6. The method for preparing a flame retardant and heat resistant epoxy resin material according to claim 5, characterized in that: The weight ratio of the 2-aminothiophenol, sodium nitrite, hydrochloric acid, furfural and the first catalyst is 2.1-2.4:1.5-1.8:4.5-6.5:0.9-1.2:0.045-0.

055.

7. The method for preparing a flame retardant and heat resistant epoxy resin material according to claim 5, characterized in that: The weight ratio of the dichloromethylvinylsilane, the intermediate and the second catalyst is 10-12:9-11:0.38-0.

46.

8. The method for preparing a flame retardant and heat resistant epoxy resin material according to claim 5, wherein: The phenylenediamine includes one of p-phenylenediamine and m-phenylenediamine.

9. The method for preparing a flame retardant and heat resistant epoxy resin material according to claim 1, wherein: The stirring and mixing time is 30 to 45 minutes.

10. A flame retardant and heat resistant epoxy resin material, characterized in that: The flame retardant and heat resistant epoxy resin material is prepared by the method for preparing the flame retardant and heat resistant epoxy resin material according to any one of claims 1 to 9.

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