Low-dielectric flame-retardant epoxy resin and preparation method thereof

Abstract

The invention relates to the technical field of epoxy resin material preparation, and discloses low-dielectric flame-retardant epoxy resin and a preparation method thereof.The low-dielectric flame-retardant epoxy resin is prepared from, by mass, 100-120 parts of epoxy resin, 10-13 parts of diluent, 8-12 parts of low-dielectric modifier, 5-10 parts of flame-retardant filler, 0.2-1 part of curing agent and 1-2 parts of dispersing agent. The flame-retardant filler and the low-dielectric modifier are mixed with the epoxy resin, and the diluent, the curing agent and the dispersing agent are compounded, so that the prepared epoxy resin composition has relatively high flame retardance and relatively low dielectric constant and dielectric loss.

Description

Technical Field

[0001] The present invention relates to the technical field of epoxy resin material preparation, in particular to a low-dielectric flame-retardant epoxy resin and a preparation method thereof. Background Art

[0002] Epoxy resin, as a thermosetting polymer, has the advantages of excellent mechanical properties, chemical corrosion resistance, electrical insulation properties, adhesion properties, easy processing and molding, and low cost. It is widely used in copper clad laminates and electronic components. The large amount of polar groups such as hydroxyl groups contained in epoxy resin makes its composite products have a large dielectric constant and dielectric loss. In addition, the limiting oxygen index of epoxy resin is low and it is flammable at high temperatures, resulting in frequent fires, which limits the application of epoxy resin in copper clad laminates and electronic components. Therefore, it is necessary to provide an epoxy resin with excellent flame retardant properties and low dielectric properties to overcome the limitations of epoxy resin in its application.

[0003] The epoxy resin is treated with a low dielectric constant and mixed with a flame retardant filler, a curing agent and an auxiliary agent to prepare an epoxy resin composition with high flame retardancy, low dielectric constant and dielectric loss, which meets the application requirements of the epoxy resin composition in copper clad laminates and electronic components. However, the flame retardant filler and the low dielectric modifier have poor compatibility with the epoxy resin and are difficult to be evenly dispersed in the resin system, which affects the flame retardancy and low dielectric properties of the epoxy resin composition. Summary of the Invention

[0004] The present invention provides a low-dielectric flame-retardant epoxy resin and a preparation method thereof, which solves the problems of poor flame-retardant performance, high dielectric constant and dielectric loss of epoxy resin.

[0005] The technical solution of the present invention: A low-dielectric flame-retardant epoxy resin comprises the following raw materials in parts by weight: 100-120 parts of epoxy resin, 10-13 parts of diluent, 8-12 parts of low-dielectric modifier, 5-10 parts of flame-retardant filler, 0.2-1 part of curing agent, and 1-2 parts of dispersant; Among them, the low dielectric modifier is obtained by attaching octaaniline propyl caged polysilsesquioxane particles to the surface of hollow glass microspheres through tannic acid and then treating the surface with a modifier. The modifier is obtained by mixing sodium perfluorooctanoate, phytic acid and dodecyl glycidyl ether; The flame retardant filler is synthesized from magnesium silicate on the surface of diatomaceous earth and then deposited on the surface of magnesium oxide whiskers through carboxymethyl cellulose; A method for preparing a low-K flame-retardant epoxy resin comprises the following steps: The epoxy resin, diluent, low dielectric modifier, flame retardant filler, curing agent and dispersant are mixed evenly, stirred at 40-60°C and 800-1000r / min for 1-2h to obtain slurry, poured into a mold, and heated and cured to obtain low dielectric flame retardant epoxy resin.

[0006] Furthermore, the epoxy resin is selected from any one of bisphenol A epoxy resin, bisphenol F epoxy resin, biphenyl epoxy resin, and alicyclic epoxy resin.

[0007] Furthermore, the heating curing temperature is 100-120° C. and the time is 1-2 hours.

[0008] Furthermore, the diluent is selected from any one of glycidyl methacrylate, butyl glycidyl ether, hexyl glycidyl ether, and p-xylyl glycidyl ether.

[0009] Furthermore, the curing agent is 2-undecyl imidazole.

[0010] Furthermore, the dispersant is selected from any one of zinc stearate, calcium stearate and magnesium stearate.

[0011] Furthermore, the low dielectric modifier is specifically prepared by the following steps: A1. Add phytic acid aqueous solution, sodium perfluorooctanoate, and dodecyl glycidyl ether to ethylene glycol butyl ether, stir until completely dissolved, and react with stirring at 60-90°C for 3-5 hours to obtain a modifier; A2. Tannic acid was added to ethanol and stirred until completely dissolved. Hollow glass microspheres were added and stirred for reaction. Octaniline propyl caged polysilsesquioxane particles were added and the reaction was continued with stirring. The mixture was filtered, washed, and dried to obtain a hollow glass microsphere composite. A3. Mix the hollow glass microsphere composite and the modifier, stir evenly, and react at 40-60°C for 2-3 hours. Filter, wash, and dry to obtain a low dielectric modifier.

[0012] Furthermore, during the above-mentioned reaction A1, the phosphate group contained in phytic acid can react with the carboxyl group of sodium perfluorooctanoate, and the phosphate group contained in phytic acid can also undergo a ring-opening reaction with the epoxy group of dodecyl glycidyl ether, so that sodium perfluorooctanoate reacts with dodecyl glycidyl ether through phytic acid to form a modifier.

[0013] Furthermore, during the above-mentioned reaction A2, tannic acid acts as a binder and adheres to the surface of the hollow glass microspheres, giving the hollow glass microspheres excellent adhesion properties, thereby being able to adsorb octaanilinepropyl caged polysilsesquioxane particles onto the surface of the hollow glass microspheres to obtain a hollow glass microsphere composite.

[0014] Furthermore, during the above reaction A3, a large number of residual phosphate groups exist in the phytic acid in the modifier, which can combine with the hollow glass microsphere composite through hydrogen bonds, so that the modifier is coated on the surface of the hollow glass microsphere composite to obtain a low dielectric modifier.

[0015] Furthermore, in step A1, the mass ratio of the phytic acid aqueous solution, sodium perfluorooctanoate, dodecyl glycidyl ether and ethylene glycol butyl ether is (15-20):(4-5):(6-7):(30-35).

[0016] Furthermore, in step A2, the mass ratio of the tannic acid, ethanol, hollow glass microspheres and octaanilinepropyl caged polysilsesquioxane particles is (1-1.2):(55-60):(2.1-2.5):(1.3-1.7).

[0017] Furthermore, in step A3, the mass ratio of the hollow glass microsphere composite to the modifier is (3-4):(25-35).

[0018] Furthermore, the particle size of the octaanilinepropyl cage-shaped polysilsesquioxane particles is 20-50 nm.

[0019] Furthermore, the flame retardant filler is specifically prepared by the following steps: B1. Add diatomaceous earth to deionized water and stir evenly. Add ammonia and cetyltrimethylammonium bromide and stir evenly. Add magnesium chloride hexahydrate and, after ultrasonic stirring, perform a hydrothermal reaction at 170-190 ° C for 4-6h. After centrifugation, washing, and drying, calcinate at 450-550 ° C for 2-5h and cool to room temperature to obtain diatomaceous earth-based magnesium silicate. B2. Add carboxymethyl cellulose to deionized water and stir until completely dissolved. Add magnesium oxide whiskers and stir to react. Then add diatomaceous earth-based magnesium silicate and continue stirring to react. After that, filter, wash, and dry to obtain a flame retardant filler.

[0020] Furthermore, during the above-mentioned B1 reaction process, in an alkaline ammonia environment, the amorphous silicon dioxide in the diatomaceous earth dissolves to form soluble silicates, and cetyltrimethylammonium bromide is adsorbed on the surface of the diatomaceous earth as a surfactant. The cations carried by it can adsorb magnesium ions in magnesium chloride hexahydrate, thereby forming amorphous magnesium silicate on the surface of the diatomaceous earth. After hydrothermal reaction and high-temperature sintering, the magnesium silicate grows vertically on the surface of the diatomaceous earth in a nanosheet structure, forming diatomaceous earth-based magnesium silicate.

[0021] Furthermore, during the above reaction B2, carboxymethyl cellulose is dissolved in deionized water to form a solution with adhesive properties, so that the carboxymethyl cellulose adheres to the surface of the magnesium oxide whiskers, and then diatomaceous earth-based magnesium silicate is added, so that the diatomaceous earth-based magnesium silicate is loaded on the surface of the magnesium oxide whiskers.

[0022] Furthermore, in step B1, the mass ratio of diatomaceous earth, deionized water, ammonia water, hexadecyltrimethylammonium bromide and magnesium chloride hexahydrate is (2-3):(55-65):(4-6):(0.01-0.03):(1.6-2).

[0023] Furthermore, in step B2, the mass ratio of carboxymethyl cellulose, deionized water, magnesium oxide whiskers and diatomaceous earth-based magnesium silicate is (0.6-1):(55-65):(2.1-2.5):(0.8-1.2).

[0024] Furthermore, the diameter of the magnesium oxide whisker is 0.1-0.2µm and the length is 0.15-0.2mm.

[0025] The present invention has the following beneficial effects: (1) In the technical solution of the present invention, sodium perfluorooctanoate is reacted with dodecyl glycidyl ether through phytic acid to obtain a modifier. On the one hand, the carbon-fluorine bond contained in sodium perfluorooctanoate can reduce the polarization performance of epoxy resin, thereby reducing the dielectric constant and dielectric loss of epoxy resin. On the other hand, the long carbon hydrophobic chain structure carried by dodecyl glycidyl ether and sodium perfluorooctanoate can be inserted into the network structure of epoxy resin, increasing the intermolecular distance of epoxy resin, reducing the polarization rate of epoxy resin, and thereby reducing the dielectric constant and dielectric loss of epoxy resin.

[0026] (2) In the technical solution of the present invention, octaaniline propyl caged polysilsesquioxane particles are adsorbed onto the surface of hollow glass microspheres through tannic acid. On the one hand, the octaaniline propyl caged polysilsesquioxane particles have a cage structure, and the hollow glass microspheres have a cavity structure, which exhibits a lower dielectric constant and dielectric loss, thereby reducing the dielectric properties of the epoxy resin. On the other hand, the octaaniline propyl caged polysilsesquioxane particles form a rough surface on the surface of the hollow glass microspheres, increasing the contact area between the hollow glass microsphere composite and the epoxy resin, so that the hollow glass microsphere composite is better dispersed in the epoxy resin, significantly reducing the dielectric properties of the epoxy resin.

[0027] (3) In the technical solution of the present invention, the modifier is coated on the surface of the hollow glass microsphere composite as a low dielectric modifier. The remaining phosphate groups of phytic acid in the low dielectric modifier can react with the epoxy groups of the epoxy resin, so that the low dielectric modifier is combined with the epoxy resin through chemical bonds, further improving the compatibility of the low dielectric modifier and the epoxy resin. The low dielectric modifier is combined with the epoxy resin through chemical bonds to enhance the bonding strength between the low dielectric modifier and the epoxy resin, thereby avoiding the migration and precipitation of the low dielectric modifier and affecting the dielectric properties of the epoxy resin.

[0028] (4) In the technical scheme of the present application, diatomite-based magnesium silicate is adhered to the surface of magnesium oxide whiskers through carboxymethyl cellulose to obtain a flame-retardant filler. On the one hand, as a high-efficiency intumescent flame retardant, the synthesized magnesium silicate can catalyze the formation of a carbon layer of carboxymethyl cellulose in the flame-retardant filler during the combustion process of epoxy resin, thereby insulating combustible gas and slowing down heat transfer, and the flame-retardant filler has good flame-retardant performance. On the other hand, diatomite has the properties of porous surface, high temperature resistance and flame retardancy, which can improve the flame-retardant performance of epoxy resin, and synergize with magnesium silicate to improve the flame-retardant performance of epoxy resin. In addition, carboxymethyl cellulose contains a large number of oxygen-containing functional groups, which can adsorb and fix metal impurities in diatomite, thereby avoiding the metal impurities from falling off into the epoxy resin and affecting the performance of the epoxy resin. Furthermore, the magnesium oxide whisker, as a carrier of diatomite-based magnesium silicate, has an excellent aspect ratio, can load more magnesium oxide whiskers, form a rough surface on the surface of the magnesium oxide whisker, increase the contact area of the flame-retardant filler and the epoxy resin, improve the dispersibility of the flame-retardant filler in the epoxy resin, and enhance the flame-retardant performance of the epoxy resin.

[0029] (5) In the technical scheme of the present application, the flame-retardant filler and the low-dielectric modifier are mixed with the epoxy resin, and a diluent, a curing agent and a dispersant are compounded to prepare an epoxy resin composition with high flame retardancy, low dielectric constant and low dielectric loss. DETAILED DESCRIPTION

[0030] The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0031] The raw materials used in the embodiments of the present application are shown below, and all the reagents used are analytical grade.

[0032] The epoxy resin is bisphenol A type epoxy resin, model BE188EL, purchased from Changchun Chemical Industry (Jiangsu) Co., Ltd.

[0033] The diluent is glycidyl methacrylate, the curing agent is 2-undecylimidazole, and the dispersant is zinc stearate.

[0034] The hollow glass microbeads have a particle size of 10 μm, and the diatomite has a particle size of 20 µm.

[0035] The octylamine propyl cage polysilsesquioxane particles have a particle size of 40 m, and are purchased from Guangzhou Yixin Technology Co., Ltd.

[0036] The magnesium oxide whisker has a diameter of 0.15 µm and a length of 0.18 mm.

[0037] Example 1 A low-dielectric flame-retardant epoxy resin, comprising the following raw materials in parts by mass: 100 parts of bisphenol A epoxy resin, 10 parts of glycidyl methacrylate, 8 parts of a low-dielectric modifier, 5 parts of a flame-retardant filler, 0.2 parts of 2-undecyl imidazole, and 1 part of zinc stearate; A method for preparing a low-K flame-retardant epoxy resin comprises the following steps: Bisphenol A epoxy resin, glycidyl methacrylate, a low dielectric modifier, a flame retardant filler, 2-undecyl imidazole, and zinc stearate were mixed evenly, stirred at 40°C and 800 r / min for 1 hour to obtain a slurry, poured into a mold, and heated and cured at 100°C for 1 hour to obtain a low dielectric flame retardant epoxy resin.

[0038] The low dielectric modifier is specifically prepared by the following steps: A1. Add a 50% (mass fraction) phytic acid aqueous solution, sodium perfluorooctanoate, and dodecyl glycidyl ether to ethylene glycol butyl ether, stir until completely dissolved, and react at 60°C for 3 hours to obtain a modifier. The mass ratio of phytic acid aqueous solution, sodium perfluorooctanoate, dodecyl glycidyl ether, and ethylene glycol butyl ether is 15:4:6:30. A2. Tannic acid was added to ethanol and stirred until completely dissolved. Hollow glass microspheres were then added and stirred at 60°C for 10 minutes. Octaaniline propyl caged polysilsesquioxane particles were then added and stirred for another 10 minutes. The mixture was filtered, washed three times with deionized water, and dried in an oven at 70°C for 10 minutes to obtain a hollow glass microsphere composite. The mass ratio of tannic acid, ethanol, hollow glass microspheres, and octaaniline propyl caged polysilsesquioxane particles was 1:55:2.1:1.3. A3. The hollow glass microsphere composite and modifier were mixed and stirred evenly. The mixture was stirred and reacted at 40°C for 2 hours. The mixture was filtered, washed three times with deionized water, and dried in a 70°C oven for 10 minutes to obtain a low-dielectric modifier. The mass ratio of the hollow glass microsphere composite to the modifier was 3:25.

[0039] The flame retardant filler is specifically prepared by the following steps: B1. The diatomaceous earth was added to deionized water, stirred evenly, and 25% mass fraction of ammonia and cetyltrimethylammonium bromide were added. The mixture was stirred at 25 ° C and 800 r / min for 30 min. Magnesium chloride hexahydrate was added and ultrasonically stirred at 40KHz for 30 min. The mixture was placed in a reactor and hydrothermally reacted at 170 ° C for 4 h. The mixture was centrifuged, washed with deionized water three times, dried in a 70 ° C oven for 10 min, placed in a muffle furnace, calcined at 450 ° C for 2 h, and cooled to room temperature to obtain diatomaceous earth-based magnesium silicate; the mass ratio of diatomaceous earth, deionized water, ammonia, cetyltrimethylammonium bromide and magnesium chloride hexahydrate was 2:55:4:0.01:1.6; B2. Add carboxymethyl cellulose to deionized water and stir until completely dissolved. Add magnesium oxide whiskers and stir at 60°C for 10 minutes. Add diatomaceous earth-based magnesium silicate and continue stirring for 10 minutes. Filter, wash three times with deionized water, and dry in an oven at 70°C for 10 minutes to obtain a flame retardant filler. The mass ratio of carboxymethyl cellulose, deionized water, magnesium oxide whiskers, and diatomaceous earth-based magnesium silicate is 0.6:55:2.1:0.8.

[0040] Example 2 A low-dielectric flame-retardant epoxy resin comprising the following raw materials in parts by weight: 110 parts of bisphenol A epoxy resin, 12 parts of glycidyl methacrylate, 10 parts of a low-dielectric modifier, 8 parts of a flame-retardant filler, 0.6 parts of 2-undecyl imidazole, and 1.5 parts of zinc stearate; A method for preparing a low-K flame-retardant epoxy resin comprises the following steps: Bisphenol A epoxy resin, glycidyl methacrylate, low dielectric modifier, flame retardant filler, 2-undecyl imidazole and zinc stearate were mixed evenly, stirred at 50°C and 900 r / min for 1.5 hours to obtain a slurry, poured into a mold, and heated and cured at 110°C for 1.5 hours to obtain a low dielectric flame retardant epoxy resin.

[0041] The low dielectric modifier is specifically prepared by the following steps: A1. Add a 50% (mass fraction) phytic acid aqueous solution, sodium perfluorooctanoate, and dodecyl glycidyl ether to ethylene glycol butyl ether and stir until completely dissolved. Stir and react at 75°C for 4 hours to obtain a modifier. The mass ratio of phytic acid aqueous solution, sodium perfluorooctanoate, dodecyl glycidyl ether, and ethylene glycol butyl ether is 18:4.5:6.5:33. A2. Tannic acid was added to ethanol and stirred until completely dissolved. Hollow glass microspheres were then added and stirred at 60°C for 10 minutes. Octaaniline propyl caged polysilsesquioxane particles were then added and stirred for another 10 minutes. The mixture was filtered, washed three times with deionized water, and dried in an oven at 70°C for 10 minutes to obtain a hollow glass microsphere composite. The mass ratio of tannic acid, ethanol, hollow glass microspheres, and octaaniline propyl caged polysilsesquioxane particles was 1.1:58:2.3:1.5. A3. The hollow glass microsphere composite and modifier were mixed and stirred evenly. The mixture was stirred and reacted at 50°C for 2.5 hours. The mixture was filtered, washed three times with deionized water, and dried in a 70°C oven for 10 minutes to obtain a low-dielectric modifier. The mass ratio of the hollow glass microsphere composite to the modifier was 3.5:30.

[0042] The flame retardant filler is specifically prepared by the following steps: B1. The diatomaceous earth was added to deionized water, stirred evenly, and 25% mass fraction of ammonia and cetyltrimethylammonium bromide were added. The mixture was stirred at 25 ° C and 800 r / min for 30 min. Magnesium chloride hexahydrate was added and ultrasonically stirred at 40KHz for 30 min. The mixture was placed in a reactor and hydrothermally reacted at 180 ° C for 5 h. The mixture was centrifuged, washed with deionized water three times, dried in a 70 ° C oven for 10 min, placed in a muffle furnace, calcined at 500 ° C for 3.5 h, and cooled to room temperature to obtain diatomaceous earth-based magnesium silicate; the mass ratio of diatomaceous earth, deionized water, ammonia, cetyltrimethylammonium bromide and magnesium chloride hexahydrate was 2.5:60:5:0.02:1.8; B2. Add carboxymethyl cellulose to deionized water and stir until completely dissolved. Add magnesium oxide whiskers and stir at 60°C for 10 minutes. Add diatomaceous earth-based magnesium silicate and continue stirring for 10 minutes. Filter, wash three times with deionized water, and dry in an oven at 70°C for 10 minutes to obtain a flame retardant filler. The mass ratio of carboxymethyl cellulose, deionized water, magnesium oxide whiskers, and diatomaceous earth-based magnesium silicate is 0.8:60:2.3:1.

[0043] Example 3 A low-dielectric flame-retardant epoxy resin comprising the following raw materials in parts by weight: 120 parts of bisphenol A epoxy resin, 13 parts of glycidyl methacrylate, 12 parts of a low-dielectric modifier, 10 parts of a flame-retardant filler, 1 part of 2-undecyl imidazole, and 2 parts of zinc stearate; A method for preparing a low-K flame-retardant epoxy resin comprises the following steps: Bisphenol A epoxy resin, glycidyl methacrylate, low dielectric modifier, flame retardant filler, 2-undecyl imidazole and zinc stearate are mixed evenly, stirred at 60°C and 1000 r / min for 2 hours to obtain a slurry, poured into a mold, and heated and cured at 120°C for 2 hours to obtain a low dielectric flame retardant epoxy resin.

[0044] The low dielectric modifier is specifically prepared by the following steps: A1. Add a 50% (mass fraction) phytic acid aqueous solution, sodium perfluorooctanoate, and dodecyl glycidyl ether to ethylene glycol butyl ether, stir until completely dissolved, and react at 90°C for 5 hours to obtain a modifier. The mass ratio of phytic acid aqueous solution, sodium perfluorooctanoate, dodecyl glycidyl ether, and ethylene glycol butyl ether is 20:5:7:35. A2. Tannic acid was added to ethanol and stirred until completely dissolved. Hollow glass microspheres were then added and stirred at 60°C for 10 minutes. Octaaniline propyl caged polysilsesquioxane particles were then added and stirred for another 10 minutes. The mixture was filtered, washed three times with deionized water, and dried in an oven at 70°C for 10 minutes to obtain a hollow glass microsphere composite. The mass ratio of tannic acid, ethanol, hollow glass microspheres, and octaaniline propyl caged polysilsesquioxane particles was 1.2:60:2.5:1.7. A3. The hollow glass microsphere composite and modifier were mixed and stirred evenly. The mixture was stirred and reacted at 60°C for 3 hours. The mixture was filtered, washed three times with deionized water, and dried in an oven at 70°C for 10 minutes to obtain a low-dielectric modifier. The mass ratio of the hollow glass microsphere composite to the modifier was 4:35.

[0045] The flame retardant filler is specifically prepared by the following steps: B1. The diatomaceous earth was added to deionized water, stirred evenly, and 25% mass fraction of ammonia and cetyltrimethylammonium bromide was added, stirred at 25 ° C, 800r / min for 30min, magnesium chloride hexahydrate was added, ultrasonically stirred at 40KHz for 30min, placed in a reactor, hydrothermally reacted at 190 ° C for 6h, centrifuged, washed with deionized water three times, dried in a 70 ° C oven for 10min, placed in a muffle furnace, calcined at 550 ° C for 5h, and cooled to room temperature to obtain diatomaceous earth-based magnesium silicate; the mass ratio of diatomaceous earth, deionized water, ammonia, cetyltrimethylammonium bromide and magnesium chloride hexahydrate was 3:65:6:0.03:2; B2. Add carboxymethyl cellulose to deionized water and stir until completely dissolved. Add magnesium oxide whiskers and stir at 60°C for 10 minutes. Add diatomaceous earth-based magnesium silicate and continue stirring for 10 minutes. Filter, wash three times with deionized water, and dry in an oven at 70°C for 10 minutes to obtain a flame retardant filler. The mass ratio of carboxymethyl cellulose, deionized water, magnesium oxide whiskers, and diatomaceous earth-based magnesium silicate is 1:65:2.5:1.2.

[0046] Comparative Example 1 A low-dielectric flame-retardant epoxy resin comprising the following raw materials in parts by weight: 120 parts of bisphenol A epoxy resin, 13 parts of glycidyl methacrylate, 12 parts of a low-dielectric modifier, 10 parts of a flame-retardant filler, 1 part of 2-undecyl imidazole, and 2 parts of zinc stearate; A method for preparing a low-K flame-retardant epoxy resin comprises the following steps: Bisphenol A epoxy resin, glycidyl methacrylate, low dielectric modifier, flame retardant filler, 2-undecyl imidazole and zinc stearate are mixed evenly, stirred at 60°C and 1000 r / min for 2 hours to obtain a slurry, poured into a mold, and heated and cured at 120°C for 2 hours to obtain a low dielectric flame retardant epoxy resin.

[0047] The low dielectric modifier is specifically prepared by the following steps: A1. Add a 50% by mass aqueous solution of phytic acid and dodecyl glycidyl ether to ethylene glycol butyl ether, stir until completely dissolved, and react at 90°C for 5 h to obtain a modifier. The mass ratio of phytic acid aqueous solution, dodecyl glycidyl ether, and ethylene glycol butyl ether is 20:12:35. A2. Tannic acid was added to ethanol and stirred until completely dissolved. Hollow glass microspheres were then added and stirred at 60°C for 10 minutes. Octaaniline propyl caged polysilsesquioxane particles were then added and stirred for another 10 minutes. The mixture was filtered, washed three times with deionized water, and dried in an oven at 70°C for 10 minutes to obtain a hollow glass microsphere composite. The mass ratio of tannic acid, ethanol, hollow glass microspheres, and octaaniline propyl caged polysilsesquioxane particles was 1.2:60:2.5:1.7. A3. The hollow glass microsphere composite and modifier were mixed and stirred evenly. The mixture was stirred and reacted at 60°C for 3 hours. The mixture was filtered, washed three times with deionized water, and dried in an oven at 70°C for 10 minutes to obtain a low-dielectric modifier. The mass ratio of the hollow glass microsphere composite to the modifier was 4:35.

[0048] The flame retardant filler is specifically prepared by the following steps: B1. The diatomaceous earth was added to deionized water, stirred evenly, and 25% mass fraction of ammonia and cetyltrimethylammonium bromide was added, stirred at 25 ° C, 800r / min for 30min, magnesium chloride hexahydrate was added, ultrasonically stirred at 40KHz for 30min, placed in a reactor, hydrothermally reacted at 190 ° C for 6h, centrifuged, washed with deionized water three times, dried in a 70 ° C oven for 10min, placed in a muffle furnace, calcined at 550 ° C for 5h, and cooled to room temperature to obtain diatomaceous earth-based magnesium silicate; the mass ratio of diatomaceous earth, deionized water, ammonia, cetyltrimethylammonium bromide and magnesium chloride hexahydrate was 3:65:6:0.03:2; B2. Add carboxymethyl cellulose to deionized water and stir until completely dissolved. Add magnesium oxide whiskers and stir at 60°C for 10 minutes. Add diatomaceous earth-based magnesium silicate and continue stirring for 10 minutes. Filter, wash three times with deionized water, and dry in an oven at 70°C for 10 minutes to obtain a flame retardant filler. The mass ratio of carboxymethyl cellulose, deionized water, magnesium oxide whiskers, and diatomaceous earth-based magnesium silicate is 1:65:2.5:1.2.

[0049] Comparative Example 2 A low-dielectric flame-retardant epoxy resin comprising the following raw materials in parts by weight: 120 parts of bisphenol A epoxy resin, 13 parts of glycidyl methacrylate, 12 parts of a low-dielectric modifier, 10 parts of a flame-retardant filler, 1 part of 2-undecyl imidazole, and 2 parts of zinc stearate; A method for preparing a low-K flame-retardant epoxy resin comprises the following steps: Bisphenol A epoxy resin, glycidyl methacrylate, low dielectric modifier, flame retardant filler, 2-undecyl imidazole and zinc stearate are mixed evenly, stirred at 60°C and 1000 r / min for 2 hours to obtain a slurry, poured into a mold, and heated and cured at 120°C for 2 hours to obtain a low dielectric flame retardant epoxy resin.

[0050] The low dielectric modifier is specifically prepared by the following steps: A1. Add sodium perfluorooctanoate and dodecyl glycidyl ether to ethylene glycol butyl ether, stir until completely dissolved, and react at 90°C for 5 hours to obtain a modifier. The mass ratio of sodium perfluorooctanoate, dodecyl glycidyl ether, and ethylene glycol butyl ether is 5:27:35. A2. Tannic acid was added to ethanol and stirred until completely dissolved. Hollow glass microspheres were then added and stirred at 60°C for 10 minutes. Octaaniline propyl caged polysilsesquioxane particles were then added and stirred for another 10 minutes. The mixture was filtered, washed three times with deionized water, and dried in an oven at 70°C for 10 minutes to obtain a hollow glass microsphere composite. The mass ratio of tannic acid, ethanol, hollow glass microspheres, and octaaniline propyl caged polysilsesquioxane particles was 1.2:60:2.5:1.7. A3. The hollow glass microsphere composite and modifier were mixed and stirred evenly. The mixture was stirred and reacted at 60°C for 3 hours. The mixture was filtered, washed three times with deionized water, and dried in an oven at 70°C for 10 minutes to obtain a low-dielectric modifier. The mass ratio of the hollow glass microsphere composite to the modifier was 4:35.

[0051] The flame retardant filler is specifically prepared by the following steps: B1. The diatomaceous earth was added to deionized water, stirred evenly, and 25% mass fraction of ammonia and cetyltrimethylammonium bromide was added, stirred at 25 ° C, 800r / min for 30min, magnesium chloride hexahydrate was added, ultrasonically stirred at 40KHz for 30min, placed in a reactor, hydrothermally reacted at 190 ° C for 6h, centrifuged, washed with deionized water three times, dried in a 70 ° C oven for 10min, placed in a muffle furnace, calcined at 550 ° C for 5h, and cooled to room temperature to obtain diatomaceous earth-based magnesium silicate; the mass ratio of diatomaceous earth, deionized water, ammonia, cetyltrimethylammonium bromide and magnesium chloride hexahydrate was 3:65:6:0.03:2; B2. Add carboxymethyl cellulose to deionized water and stir until completely dissolved. Add magnesium oxide whiskers and stir at 60°C for 10 minutes. Add diatomaceous earth-based magnesium silicate and continue stirring for 10 minutes. Filter, wash three times with deionized water, and dry in an oven at 70°C for 10 minutes to obtain a flame retardant filler. The mass ratio of carboxymethyl cellulose, deionized water, magnesium oxide whiskers, and diatomaceous earth-based magnesium silicate is 1:65:2.5:1.2.

[0052] Comparative Example 3 A low-dielectric flame-retardant epoxy resin comprising the following raw materials in parts by weight: 120 parts of bisphenol A epoxy resin, 13 parts of glycidyl methacrylate, 12 parts of a low-dielectric modifier, 10 parts of a flame-retardant filler, 1 part of 2-undecyl imidazole, and 2 parts of zinc stearate; A method for preparing a low-K flame-retardant epoxy resin comprises the following steps: Bisphenol A epoxy resin, glycidyl methacrylate, low dielectric modifier, flame retardant filler, 2-undecyl imidazole and zinc stearate are mixed evenly, stirred at 60°C and 1000 r / min for 2 hours to obtain a slurry, poured into a mold, and heated and cured at 120°C for 2 hours to obtain a low dielectric flame retardant epoxy resin.

[0053] The low dielectric modifier is specifically prepared by the following steps: A1. Add a 50% (mass fraction) phytic acid aqueous solution, sodium perfluorooctanoate, and dodecyl glycidyl ether to ethylene glycol butyl ether, stir until completely dissolved, and react at 90°C for 5 hours to obtain a modifier. The mass ratio of phytic acid aqueous solution, sodium perfluorooctanoate, dodecyl glycidyl ether, and ethylene glycol butyl ether is 20:5:7:35. A2. Ethanol and hollow glass microspheres were mixed and stirred at 60°C for 10 minutes. Octaanilinepropyl caged polysilsesquioxane particles were added and stirred for another 10 minutes. The mixture was filtered, washed three times with deionized water, and dried in an oven at 70°C for 10 minutes to obtain a hollow glass microsphere composite. The mass ratio of ethanol, hollow glass microspheres, and octaanilinepropyl caged polysilsesquioxane particles was 61.2:2.5:1.7. A3. The hollow glass microsphere composite and modifier were mixed and stirred evenly. The mixture was stirred and reacted at 60°C for 3 hours. The mixture was filtered, washed three times with deionized water, and dried in an oven at 70°C for 10 minutes to obtain a low-dielectric modifier. The mass ratio of the hollow glass microsphere composite to the modifier was 4:35.

[0054] The flame retardant filler is specifically prepared by the following steps: B1. The diatomaceous earth was added to deionized water, stirred evenly, and 25% mass fraction of ammonia and cetyltrimethylammonium bromide was added, stirred at 25 ° C, 800r / min for 30min, magnesium chloride hexahydrate was added, ultrasonically stirred at 40KHz for 30min, placed in a reactor, hydrothermally reacted at 190 ° C for 6h, centrifuged, washed with deionized water three times, dried in a 70 ° C oven for 10min, placed in a muffle furnace, calcined at 550 ° C for 5h, and cooled to room temperature to obtain diatomaceous earth-based magnesium silicate; the mass ratio of diatomaceous earth, deionized water, ammonia, cetyltrimethylammonium bromide and magnesium chloride hexahydrate was 3:65:6:0.03:2; B2. Add carboxymethyl cellulose to deionized water and stir until completely dissolved. Add magnesium oxide whiskers and stir at 60°C for 10 minutes. Add diatomaceous earth-based magnesium silicate and continue stirring for 10 minutes. Filter, wash three times with deionized water, and dry in an oven at 70°C for 10 minutes to obtain a flame retardant filler. The mass ratio of carboxymethyl cellulose, deionized water, magnesium oxide whiskers, and diatomaceous earth-based magnesium silicate is 1:65:2.5:1.2.

[0055] Comparative Example 4 A low-dielectric flame-retardant epoxy resin comprising the following raw materials in parts by weight: 120 parts of bisphenol A epoxy resin, 13 parts of glycidyl methacrylate, 12 parts of a low-dielectric modifier, 10 parts of a flame-retardant filler, 1 part of 2-undecyl imidazole, and 2 parts of zinc stearate; A method for preparing a low-K flame-retardant epoxy resin comprises the following steps: Bisphenol A epoxy resin, glycidyl methacrylate, low dielectric modifier, flame retardant filler, 2-undecyl imidazole and zinc stearate are mixed evenly, stirred at 60°C and 1000 r / min for 2 hours to obtain a slurry, poured into a mold, and heated and cured at 120°C for 2 hours to obtain a low dielectric flame retardant epoxy resin.

[0056] The low dielectric modifier is specifically prepared by the following steps: A1. Add a 50% (mass fraction) phytic acid aqueous solution, sodium perfluorooctanoate, and dodecyl glycidyl ether to ethylene glycol butyl ether, stir until completely dissolved, and react at 90°C for 5 hours to obtain a modifier. The mass ratio of phytic acid aqueous solution, sodium perfluorooctanoate, dodecyl glycidyl ether, and ethylene glycol butyl ether is 20:5:7:35. A2. Tannic acid was added to ethanol and stirred until completely dissolved. Hollow glass microspheres were then added and stirred at 60°C for 10 minutes. Octaaniline propyl caged polysilsesquioxane particles were then added and stirred for another 10 minutes. The mixture was filtered, washed three times with deionized water, and dried in an oven at 70°C for 10 minutes to obtain a hollow glass microsphere composite. The mass ratio of tannic acid, ethanol, hollow glass microspheres, and octaaniline propyl caged polysilsesquioxane particles was 1.2:60:2.5:1.7. A3. The hollow glass microsphere composite and modifier were mixed and stirred evenly. The mixture was stirred and reacted at 60°C for 3 hours. The mixture was filtered, washed three times with deionized water, and dried in an oven at 70°C for 10 minutes to obtain a low-dielectric modifier. The mass ratio of the hollow glass microsphere composite to the modifier was 4:35.

[0057] The flame retardant filler is specifically prepared by the following steps: Carboxymethyl cellulose was added to deionized water and stirred until completely dissolved. Magnesium oxide whiskers were added and stirred at 60°C for 10 minutes. Diatomaceous earth was added and stirred for 10 minutes. The mixture was filtered, washed with deionized water three times, and dried in an oven at 70°C for 10 minutes to obtain a flame retardant filler. The mass ratio of carboxymethyl cellulose, ethanol, magnesium oxide whiskers and diatomaceous earth was 1:65:2.5:1.2.

[0058] Comparative Example 5 A low-dielectric flame-retardant epoxy resin comprising the following raw materials in parts by weight: 120 parts of bisphenol A epoxy resin, 13 parts of glycidyl methacrylate, 12 parts of a low-dielectric modifier, 10 parts of a flame-retardant filler, 1 part of 2-undecyl imidazole, and 2 parts of zinc stearate; A method for preparing a low-K flame-retardant epoxy resin comprises the following steps: Bisphenol A epoxy resin, glycidyl methacrylate, low dielectric modifier, flame retardant filler, 2-undecyl imidazole and zinc stearate are mixed evenly, stirred at 60°C and 1000 r / min for 2 hours to obtain a slurry, poured into a mold, and heated and cured at 120°C for 2 hours to obtain a low dielectric flame retardant epoxy resin.

[0059] The low dielectric modifier is specifically prepared by the following steps: A1. Add a 50% (mass fraction) phytic acid aqueous solution, sodium perfluorooctanoate, and dodecyl glycidyl ether to ethylene glycol butyl ether, stir until completely dissolved, and react at 90°C for 5 hours to obtain a modifier. The mass ratio of phytic acid aqueous solution, sodium perfluorooctanoate, dodecyl glycidyl ether, and ethylene glycol butyl ether is 20:5:7:35. A2. Tannic acid was added to ethanol and stirred until completely dissolved. Hollow glass microspheres were then added and stirred at 60°C for 10 minutes. Octaaniline propyl caged polysilsesquioxane particles were then added and stirred for another 10 minutes. The mixture was filtered, washed three times with deionized water, and dried in an oven at 70°C for 10 minutes to obtain a hollow glass microsphere composite. The mass ratio of tannic acid, ethanol, hollow glass microspheres, and octaaniline propyl caged polysilsesquioxane particles was 1.2:60:2.5:1.7. A3. The hollow glass microsphere composite and modifier were mixed and stirred evenly. The mixture was stirred and reacted at 60°C for 3 hours. The mixture was filtered, washed three times with deionized water, and dried in an oven at 70°C for 10 minutes to obtain a low-dielectric modifier. The mass ratio of the hollow glass microsphere composite to the modifier was 4:35.

[0060] The flame retardant filler is specifically prepared by the following steps: B1. The diatomaceous earth was added to deionized water, stirred evenly, and 25% mass fraction of ammonia and cetyltrimethylammonium bromide was added, stirred at 25 ° C, 800r / min for 30min, magnesium chloride hexahydrate was added, ultrasonically stirred at 40KHz for 30min, placed in a reactor, hydrothermally reacted at 190 ° C for 6h, centrifuged, washed with deionized water three times, dried in a 70 ° C oven for 10min, placed in a muffle furnace, calcined at 550 ° C for 5h, and cooled to room temperature to obtain diatomaceous earth-based magnesium silicate; the mass ratio of diatomaceous earth, deionized water, ammonia, cetyltrimethylammonium bromide and magnesium chloride hexahydrate was 3:65:6:0.03:2; B2. Mix deionized water and magnesium oxide whiskers, stir at 60°C for 10 minutes, add diatomaceous earth-based magnesium silicate, continue stirring for 10 minutes, filter, wash three times with deionized water, and dry in a 70°C oven for 10 minutes to obtain a flame-retardant filler; the mass ratio of deionized water, magnesium oxide whiskers, and diatomaceous earth-based magnesium silicate is 66:2.5:1.2.

[0061] The performance of the low-dielectric flame-retardant epoxy resins prepared in Examples 1-3 and Comparative Examples 1-5 was tested.

[0062] Dielectric property test: The dielectric constant and dielectric loss of the low-dielectric flame-retardant epoxy resin prepared above were tested according to GB / T31838.1-2015 standard. The test frequency range was 1×10 6 Hz.

[0063] Flame retardant performance test: The flame retardant performance of the low-dielectric flame-retardant epoxy resin prepared above was tested according to GB / T2408-2008 and GBT2406.1-2008 standards.

[0064] As shown in Table 1 below.

[0065] Table 1 Performance test of low dielectric constant flame retardant epoxy resin prepared in Examples 1-3 and Comparative Examples 1-5 It can be seen from the data in Table 1 that the low-dielectric flame-retardant epoxy resins prepared in Examples 1-3 have relatively high flame retardant properties and relatively low dielectric properties.

[0066] In Comparative Example 1, a low-dielectric modifier prepared by replacing the mass of sodium perfluorooctanoate with dodecyl glycidyl ether was added to the low-dielectric flame-retardant epoxy resin, and its dielectric constant and dielectric loss were relatively high, proving that sodium perfluorooctanoate contains carbon-fluorine bonds that can reduce the polarization properties of the epoxy resin, thereby reducing the dielectric constant and dielectric loss of the epoxy resin, and the long carbon hydrophobic chain structure carried by sodium perfluorooctanoate can be inserted into the network structure of the epoxy resin, increasing the intermolecular distance of the epoxy resin, reducing the polarization rate of the epoxy resin, and thereby reducing the dielectric constant and dielectric loss of the epoxy resin.

[0067] In Comparative Example 2, a low-dielectric modifier prepared by replacing the mass of phytic acid aqueous solution with dodecyl glycidyl ether is added to the low-dielectric flame-retardant epoxy resin. The dielectric constant and dielectric loss are relatively high, which proves that the modifier obtained by reacting sodium perfluorooctanoate with phytic acid and dodecyl glycidyl ether can be coated on the surface of the hollow glass microsphere composite. The remaining phosphate groups of the phytic acid can react with the epoxy groups of the epoxy resin, so that the low-dielectric modifier is combined with the epoxy resin through chemical bonds, thereby improving the compatibility of the low-dielectric modifier with the epoxy resin, and thus reducing the dielectric constant and dielectric loss of the epoxy resin.

[0068] In Comparative Example 3, a low-dielectric modifier prepared by replacing the mass of tannic acid with ethanol was added to the low-dielectric flame-retardant epoxy resin. Its dielectric constant and dielectric loss were relatively high, proving that the octaanilinepropyl cage-like polysilsesquioxane particles were adsorbed to the surface of the hollow glass microspheres through tannic acid to form a rough surface, thereby increasing the contact area between the hollow glass microsphere composite and the epoxy resin and significantly reducing the dielectric properties of the epoxy resin.

[0069] In Comparative Example 4, the mass of diatomaceous earth-based magnesium silicate is replaced with a flame retardant filler prepared from diatomaceous earth and added to the low-dielectric flame retardant epoxy resin. Its flame retardant performance decreases, proving that the magnesium silicate synthesized on the surface of diatomaceous earth is a high-efficiency expansion flame retardant. During the combustion process of the epoxy resin, it can catalyze the carboxymethyl cellulose in the flame retardant filler to form a carbon layer, and can also promote the formation of a carbon layer by phytic acid and tannic acid in the low-dielectric modifier, and has good flame retardant properties.

[0070] In Comparative Example 5, a flame retardant filler prepared by replacing the mass of carboxymethyl cellulose with deionized water was added to a low-dielectric flame retardant epoxy resin, and its flame retardant properties decreased, proving that carboxymethyl cellulose contains a large number of oxygen-containing functional groups, which can adsorb and fix metal impurities in diatomaceous earth, prevent the metal impurities from falling into the epoxy resin and affecting the performance of the epoxy resin, and carboxymethyl cellulose can form a carbon layer during the combustion process and has flame retardant properties. In addition, diatomaceous earth-based magnesium silicate adheres to the surface of magnesium oxide whiskers through carboxymethyl cellulose, forming a rough surface on the surface of the magnesium oxide whiskers, increasing the contact area between the flame retardant filler and the epoxy resin, improving the dispersibility of the flame retardant filler in the epoxy resin, and enhancing the flame retardant properties of the epoxy resin.

[0071] Throughout the specification, references to terms such as "one embodiment," "example," or "specific example" indicate that the specific features, structures, materials, or characteristics described in conjunction with that embodiment or example are included in at least one embodiment or example of the present invention. In this specification, schematic representations of these terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0072] The above contents are merely examples and explanations of the present invention. Those skilled in the art may make various modifications or additions to the described specific embodiments or replace them in similar ways. As long as they do not deviate from the invention or exceed the scope defined by the claims, they should all fall within the scope of protection of the present invention.

Claims

1. A low-dielectric flame-retardant epoxy resin, characterized in that: The invention comprises the following raw materials in parts by weight: 100-120 parts of epoxy resin, 10-13 parts of diluent, 8-12 parts of low dielectric modifier, 5-10 parts of flame retardant filler, 0.2-1 parts of curing agent, and 1-2 parts of dispersant; Among them, the low dielectric modifier is obtained by attaching octaaniline propyl caged polysilsesquioxane particles to the surface of hollow glass microspheres through tannic acid and then treating the surface with a modifier. The modifier is obtained by mixing sodium perfluorooctanoate, phytic acid and dodecyl glycidyl ether; The flame retardant filler is synthesized from magnesium silicate on the surface of diatomaceous earth and then deposited on the surface of magnesium oxide whiskers through carboxymethyl cellulose.

2. A low-K flame-retardant epoxy resin according to claim 1, characterized in that: The low dielectric modifier is specifically prepared by the following steps: A1. Add phytic acid aqueous solution, sodium perfluorooctanoate, and dodecyl glycidyl ether to ethylene glycol butyl ether, stir until completely dissolved, and react with stirring at 60-90°C for 3-5 hours to obtain a modifier; A2. Tannic acid was added to ethanol and stirred until completely dissolved. Hollow glass microspheres were added and stirred for reaction. Octaniline propyl caged polysilsesquioxane particles were added and the reaction was continued with stirring. The mixture was filtered, washed, and dried to obtain a hollow glass microsphere composite. A3. Mix the hollow glass microsphere composite and the modifier, stir evenly, and react at 40-60°C for 2-3 hours. Filter, wash, and dry to obtain a low dielectric modifier.

3. A low-K flame-retardant epoxy resin according to claim 2, characterized in that: In step A1, the mass ratio of the phytic acid aqueous solution, sodium perfluorooctanoate, dodecyl glycidyl ether and ethylene glycol butyl ether is (15-20):(4-5):(6-7):(30-35).

4. A low-K flame-retardant epoxy resin according to claim 2, characterized in that: In step A2, the mass ratio of the tannic acid, ethanol, hollow glass microspheres and octaanilinepropyl caged polysilsesquioxane particles is (1-1.2):(55-60):(2.1-2.5):(1.3-1.7).

5. The low-K flame-retardant epoxy resin according to claim 2, characterized in that: In step A3, the mass ratio of the hollow glass microsphere composite to the modifier is (3-4):(25-35).

6. The low-K flame-retardant epoxy resin according to claim 1, characterized in that: The flame retardant filler is specifically prepared by the following steps: B1. Add diatomaceous earth to deionized water and stir evenly. Add ammonia and cetyltrimethylammonium bromide and stir evenly. Add magnesium chloride hexahydrate and, after ultrasonic stirring, perform a hydrothermal reaction at 170-190 ° C for 4-6h. After centrifugation, washing, and drying, calcinate at 450-550 ° C for 2-5h and cool to room temperature to obtain diatomaceous earth-based magnesium silicate. B2. Add carboxymethyl cellulose to deionized water and stir until completely dissolved. Add magnesium oxide whiskers and stir to react. Then add diatomaceous earth-based magnesium silicate and continue stirring to react. After that, filter, wash, and dry to obtain a flame retardant filler.

7. The low-K flame-retardant epoxy resin according to claim 6, characterized in that: In step B1, the mass ratio of diatomaceous earth, deionized water, ammonia water, hexadecyltrimethylammonium bromide and magnesium chloride hexahydrate is (2-3):(55-65):(4-6):(0.01-0.03):(1.6-2).

8. The low-K flame-retardant epoxy resin according to claim 6, characterized in that: In step B2, the mass ratio of the carboxymethyl cellulose, deionized water, magnesium oxide whiskers and diatomaceous earth-based magnesium silicate is (0.6-1):(55-65):(2.1-2.5):(0.8-1.2).

9. A method for preparing a low-K flame-retardant epoxy resin according to any one of claims 1 to 8, characterized in that: The method comprises the following preparation steps: The epoxy resin, diluent, low dielectric modifier, flame retardant filler, curing agent and dispersant are mixed evenly, stirred at 40-60°C and 800-1000r / min for 1-2h to obtain slurry, poured into a mold, and heated and cured to obtain low dielectric flame retardant epoxy resin.

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