A method for preparing an epoxy resin composite plate for an automobile containing basalt fibers

Abstract

The present application relates to the technical field of epoxy resin composite board, in particular to a preparation method of an automobile epoxy resin composite board containing basalt fiber: including the following raw materials by weight: epoxy resin 50-80 parts, curing agent 4-8 parts, reinforcing material 3-6 parts, flame retardant 1-3 parts, color agent 0.2-0.4 parts.In the present application, the surface of basalt flake is bridged by polydiallyldimethylammonium chloride, and graphene microsheets and hexagonal boron nitride nanosheets are firmly loaded, which can consume a large amount of fracture energy, and the carbon nanotubes modified by polydopamine have high aspect ratio and excellent interfacial bonding force, and are connected between different reinforcing bodies, further transmitting stress and preventing crack coalescence and expansion, so that the composite board can effectively disperse and absorb energy when impacted and stretched, thereby simultaneously achieving significant improvement in high strength, high modulus and high toughness.

Description

Technical Field

[0001] This invention relates to the field of epoxy resin composite board technology, specifically to a method for preparing an automotive epoxy resin composite board containing basalt fibers. Background Technology

[0002] Epoxy resin composites are high-performance materials made by adding various reinforcing materials to epoxy resin as the matrix. They combine the excellent adhesion, corrosion resistance and mechanical properties of epoxy resin with the high strength and high modulus of reinforcing materials. They have high strength, high toughness, good chemical stability and dimensional stability, and are widely used in aerospace, automotive manufacturing, electronics and electrical appliances and other fields.

[0003] Currently, epoxy resin composites are highly favored in the automotive lightweighting process due to their high specific strength. While the highly cross-linked three-dimensional network structure formed after epoxy resin curing provides high modulus and strength, it severely restricts the mobility of molecular chains. When the material is subjected to impact and stress, energy cannot be dissipated through dispersion and absorption. This inherent brittleness of epoxy resin makes it prone to fracture when applied to automotive sheet metal due to insufficient toughness. Therefore, this invention provides a method for preparing an epoxy resin composite sheet for automotive applications containing basalt fibers. Summary of the Invention

[0004] The purpose of this invention is to provide a method for preparing an epoxy resin composite board for automobiles containing basalt fibers, so as to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, the present invention provides the following technical solution: an epoxy resin composite board for automobiles containing basalt fiber, comprising the following raw materials in parts by weight: 50-80 parts epoxy resin, 4-8 parts curing agent, 3-6 parts reinforcing material, 1-3 parts flame retardant, and 0.2-0.4 parts colorant;

[0006] The reinforcing material is prepared by the following method:

[0007] Step 1: Preparation of the mixture. The raw materials of the mixture include fiber material, graphene micro flakes, tetrabutyl titanate, hexagonal boron nitride, deionized water, terephthalic acid, and urea. The fiber material is selected from basalt flakes.

[0008] Step 2: Preparation of additives. The raw materials for additives include carbon nanotubes, tris(hydroxymethyl)aminomethane, deionized water, and dopamine hydrochloride. The mass of the additives is 10-20% of the mass of the mixture.

[0009] Step 3: Mix the mixture with the additives to obtain the reinforcing material.

[0010] Preferably, the method for preparing the mixture is as follows: Fiber material, graphene microsheets, tetrabutyl titanate, hexagonal boron nitride, and deionized water are added to a mixer, which is set to 200-400 rpm and stirred for 20-40 minutes. Then, polydiallyldimethylammonium chloride is added to the mixer, which is set to 60-100 rpm and stirred for 2-4 hours. The resulting product is added to a centrifuge, which is set to 8000-10000 rpm and centrifuged for 6-10 minutes. The centrifuged product yields a solid, which is washed with deionized water to obtain a coarse material. The coarse material, terephthalic acid, and urea are then added to a reaction mixture... In the reactor, the temperature is set at 120–140℃, the stirring speed is 100–200 rpm, and the mixture is stirred at a constant temperature for 40–60 minutes. After cooling to room temperature, 2–4 times the mass of the coarse material is added to the reactor, and the mixture is stirred at 200–400 rpm for 10–20 minutes. The resulting product is then added to a centrifuge, which is set to 8000–10000 rpm for 6–10 minutes. The centrifuged product yields a precipitate, which is washed with deionized water and then placed in an oven at 80–100℃ for 2–4 hours to obtain a mixture.

[0011] Preferably, the mass ratio of fiber material, graphene microsheets, tetrabutyl titanate, hexagonal boron nitride, and deionized water is 1:(0.2-0.4):(0.04-0.06):(0.8-1.2):(40-60), and the mass ratio of coarse material, terephthalic acid, and urea is 1:(0.04-0.06):(0.2-0.3).

[0012] Preferably, the fiber material is prepared by the following method: basalt flakes are soaked in an aqueous solution containing a silane coupling agent with a mass concentration of 0.3-0.6% for 2-4 hours. After soaking, the basalt flakes are placed in an oven and dried at 80-120°C for 2-4 hours to obtain a base material. The base material, xylene, and nano-silica dispersion are added to a mixer and stirred at 60-80 rpm for 40-60 minutes. The resulting product is added to a centrifuge and centrifuged at 10000-12000 rpm for 6-10 minutes. The resulting solids are washed with ethanol 4-6 times and then placed in an oven and dried at 100-120°C for 2-4 hours to obtain the fiber material.

[0013] Preferably, the silane coupling agent is KH550, and the mass ratio of the base material, xylene, and nano-silica dispersion is 1:(10-12):(0.05-0.07).

[0014] Preferably, the method for preparing the additive is as follows: carbon nanotubes, tris(hydroxymethyl)aminomethane, and deionized water are added to a reaction vessel. The reaction vessel is set to a temperature of 40–60°C and a rotation speed of 400–600 rpm. The mixture is stirred at a constant temperature for 40–60 min. After cooling to room temperature, dopamine hydrochloride is added to the reaction vessel, and the mixture is stirred for another 10–20 min. The resulting product is added to a centrifuge and centrifuged at 6000–8000 rpm for 10–12 min. The precipitated product is collected and then washed 3–5 times alternately with ethanol and deionized water by stirring. The resulting product is added to a vacuum drying oven and dried at 60–70°C for 6–8 h to obtain the additive.

[0015] Preferably, the mass ratio of carbon nanotubes, tris(hydroxymethyl)aminomethane, and deionized water is 1:(0.04-0.06):(8-10), and the mass of dopamine hydrochloride is 6-8% of the mass of carbon nanotubes.

[0016] Preferably, the curing agent is T-31.

[0017] Preferably, the flame retardant is dimethyl methyl phosphate.

[0018] Preferably, a method for preparing an epoxy resin composite board for automobiles containing basalt fibers includes the following steps:

[0019] S1: Weigh out epoxy resin, curing agent, reinforcing agent, flame retardant and colorant as needed and add them to the mixing tank. Stir at 300-400 r / min for 30-50 min to obtain a mixture.

[0020] S2: Transfer the mixture to an open mixing vessel, set the temperature to 55-65℃, the speed to 100-150r / min, and continue constant temperature stirring for 3-4 hours, stopping for 5 minutes every 30 minutes of stirring to obtain the mixture;

[0021] S3: Pour the mixture into a mold preheated to 80°C, cure it under 10MPa pressure for 4-5 hours, and then cool it to 50-60°C to demold it, thus obtaining an epoxy resin composite board for automobiles containing basalt fiber.

[0022] Compared with the prior art, the beneficial effects of the present invention are:

[0023] 1. In this invention, basalt flakes, graphene microsheets, and carbon nanotubes work synergistically to enhance strength performance. Graphene microsheets disperse stress during crack initiation, while carbon nanotubes transfer stress through their tensile strength, preventing microcracks from opening or merging. The basalt flakes, bearing the main load, act as a macroscopic framework. Their surface is bridged by polydiallyldimethylammonium chloride, firmly supporting graphene microsheets and hexagonal boron nitride nanosheets. These nanosheets effectively pin the matrix, bridge microcracks, and deflect crack propagation paths, consuming a large amount of fracture energy. Meanwhile, polydopamine-modified carbon nanotubes, with their high aspect ratio and excellent interfacial bonding, shuttle between different reinforcements, further transferring stress and preventing crack merging and propagation. Thus, the composite plate can effectively disperse and absorb energy when subjected to impact and tension, thereby achieving a significant improvement in high strength, high modulus, and high toughness simultaneously.

[0024] 2. In this invention, KH550 treatment grafts amino functional groups onto the surface of basalt flakes, forming a strong chemical bond with the epoxy resin matrix. This improves the wettability and bonding strength between the fiber and the resin. Furthermore, the functional groups on the polydopamine surface not only form strong π-π conjugation and hydrogen bonding with carbon nanotubes, but also undergo strong entanglement and chemical reactions with epoxy resin molecular chains, enhancing interfacial density. The addition of nano-silica dispersion fills the microscopic gaps between the fiber and resin, forming a denser interfacial region. This region acts as a barrier against the penetration of corrosive media such as water vapor, oxygen, and ions, preventing media intrusion along weak interfaces and providing excellent corrosion resistance. The interfacial coupling fundamentally reduces stress concentration, preventing interface debonding between the reinforcement and the matrix, ensuring efficient load transfer. Simultaneously, the dense interfacial layer effectively blocks the intrusion of water vapor and corrosive media, significantly improving the long-term durability and dimensional stability of the composite material under harsh environments such as humidity, heat, and vibration. Attached Figure Description

[0025] Figure 1 The present invention provides a flowchart of a method for preparing an epoxy resin composite board for automobiles containing basalt fibers. Detailed Implementation

[0026] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0027] It should be noted that the raw materials used in the following embodiments are all commercially available.

[0028] Example 1:

[0029] An epoxy resin composite board for automobiles containing basalt fiber comprises the following raw materials in parts by weight: 50 parts epoxy resin, 4 parts curing agent, 3 parts reinforcing agent, 1 part flame retardant, and 0.2 parts colorant.

[0030] The reinforcing material is prepared by the following method:

[0031] Step 1: Preparation of the mixture. The raw materials for the mixture include fiber material, graphene micro flakes, tetrabutyl titanate, hexagonal boron nitride, deionized water, terephthalic acid, and urea. Basalt flakes are selected as the raw material for the fiber material.

[0032] The method for preparing the mixture is as follows: Fiber material, graphene microsheets, tetrabutyl titanate, hexagonal boron nitride, and deionized water are added to a mixer, which is set to 200 rpm and stirred for 20 minutes. Then, polydiallyl dimethyl ammonium chloride is added to the mixer, and the mixer is set to 60 rpm and stirred for 2 hours. The resulting product is added to a centrifuge, which is set to 8000 rpm and centrifuged for 6 minutes. The centrifuged product yields a solid, which is washed with deionized water to obtain a coarse material. The coarse material, terephthalic acid, and... Urea was added to a reactor, which was set to a temperature of 120°C and a stirring speed of 100 rpm. The mixture was stirred at this constant temperature for 40 minutes. After cooling to room temperature, twice the mass of the crude material was added to the reactor and stirred at 200 rpm for 10 minutes. The resulting product was then added to a centrifuge and centrifuged at 8000 rpm for 6 minutes. The precipitate was obtained from the centrifugation process and washed with deionized water. The precipitate was then placed in an oven and dried at 80°C for 2 hours to obtain a mixture.

[0033] The mass ratio of fiber material, graphene microsheets, tetrabutyl titanate, hexagonal boron nitride, and deionized water is 1:0.2:0.04:0.8:40, and the mass ratio of coarse material, terephthalic acid, and urea is 1:0.04:0.2.

[0034] The fiber material is prepared by the following method: basalt flakes are soaked in an aqueous solution containing a silane coupling agent with a mass concentration of 0.3% for 2 hours. After soaking, the basalt flakes are placed in an oven and dried at 80°C for 2 hours to obtain the base material. The base material, xylene, and nano-silica dispersion are added to a mixer and stirred at 60 rpm for 40 minutes. The resulting product is added to a centrifuge and centrifuged at 10,000 rpm for 6 minutes. The resulting solids are washed four times with ethanol and then added to an oven and dried at 100°C for 2 hours to obtain the fiber material.

[0035] The silane coupling agent used is KH550, and the mass ratio of the base material, xylene, and nano silica dispersion is 1:10:0.05.

[0036] Step 2: Preparation of additives. The raw materials for additives include carbon nanotubes, tris(hydroxymethyl)aminomethane, deionized water, and dopamine hydrochloride. The mass of the additives is 10% of the mass of the mixture.

[0037] The method for preparing the additive is as follows: carbon nanotubes, tris(hydroxymethyl)aminomethane, and deionized water are added to a reaction vessel. The reaction vessel is set to a temperature of 40°C and a rotation speed of 400 rpm. The mixture is stirred at a constant temperature for 40 min. After cooling to room temperature, dopamine hydrochloride is added to the reaction vessel, and the mixture is stirred for another 10 min. The resulting product is added to a centrifuge and centrifuged at 6000 rpm for 10 min. The precipitate is collected and then washed three times with ethanol and deionized water by stirring. The resulting product is added to a vacuum drying oven and dried at 60°C for 6 h to obtain the additive.

[0038] The mass ratio of carbon nanotubes, tris(hydroxymethyl)aminomethane, and deionized water is 1:0.04:8, and the mass of dopamine hydrochloride is 6% of the mass of carbon nanotubes.

[0039] Step 3: Mix the mixture with the additives to obtain the reinforcing material.

[0040] Among them, T-31 is selected as the curing agent.

[0041] The flame retardant selected is dimethyl methyl phosphate.

[0042] A method for preparing an epoxy resin composite board for automobiles containing basalt fibers includes the following steps:

[0043] S1: Weigh out epoxy resin, curing agent, reinforcing agent, flame retardant and colorant as needed and add them to the mixing tank. Stir at 300 r / min for 30 min to obtain a mixture.

[0044] S2: Transfer the mixture to an open mixing vessel, set the temperature to 55℃, the speed to 100r / min, and continuously stir at a constant temperature for 3 hours, stopping for 5 minutes every 30 minutes to obtain the mixture;

[0045] S3: Pour the mixture into a mold preheated to 80°C, cure it under 10MPa pressure for 4 hours, and then cool it to 50°C to demold, thus obtaining an epoxy resin composite board for automobiles containing basalt fiber.

[0046] Example 2:

[0047] An epoxy resin composite board for automobiles containing basalt fiber comprises the following raw materials in parts by weight: 65 parts epoxy resin, 6 parts curing agent, 5 parts reinforcing agent, 2 parts flame retardant, and 0.3 parts colorant.

[0048] The reinforcing material is prepared by the following method:

[0049] Step 1: Preparation of the mixture. The raw materials for the mixture include fiber material, graphene micro flakes, tetrabutyl titanate, hexagonal boron nitride, deionized water, terephthalic acid, and urea. Basalt flakes are selected as the raw material for the fiber material.

[0050] The method for preparing the mixture is as follows: Fiber material, graphene microsheets, tetrabutyl titanate, hexagonal boron nitride, and deionized water are added to a mixer, which is set to 300 rpm and stirred for 30 minutes. Then, polydiallyl dimethyl ammonium chloride is added to the mixer, and the mixer is set to 80 rpm and stirred for 3 hours. The resulting product is added to a centrifuge, which is set to 9000 rpm and centrifuged for 8 minutes. The centrifuged product yields a solid, which is washed with deionized water to obtain a coarse material. The coarse material, terephthalic acid, and... Urea was added to a reactor, which was set to a temperature of 130°C and a stirring speed of 150 rpm. The mixture was stirred at this constant temperature for 50 minutes. After cooling to room temperature, three times the mass of the crude material was added to the reactor and stirred at 300 rpm for 15 minutes. The resulting product was then added to a centrifuge and centrifuged at 9000 rpm for 8 minutes. The precipitate was obtained from the centrifuged product and washed with deionized water. The precipitate was then placed in an oven and dried at 90°C for 3 hours to obtain a mixture.

[0051] The mass ratio of fiber material, graphene microsheets, tetrabutyl titanate, hexagonal boron nitride, and deionized water is 1:0.3:0.05:1:50, and the mass ratio of coarse material, terephthalic acid, and urea is 1:0.05:0.25.

[0052] The fiber material is prepared by the following method: basalt flakes are soaked in an aqueous solution containing a silane coupling agent with a mass concentration of 0.45% for 3 hours. After soaking, the basalt flakes are placed in an oven and dried at 100°C for 3 hours to obtain the base material. The base material, xylene, and nano-silica dispersion are added to a mixer and stirred at 70 rpm for 50 minutes. The resulting product is added to a centrifuge and centrifuged at 11000 rpm for 8 minutes. The resulting solids are washed five times with ethanol and then added to an oven and dried at 110°C for 3 hours to obtain the fiber material.

[0053] The silane coupling agent used is KH550, and the mass ratio of the base material, xylene, and nano silica dispersion is 1:11:0.06.

[0054] Step 2: Preparation of additives. The raw materials for additives include carbon nanotubes, tris(hydroxymethyl)aminomethane, deionized water, and dopamine hydrochloride. The mass of the additives is 15% of the mass of the mixture.

[0055] The method for preparing the additive is as follows: carbon nanotubes, tris(hydroxymethyl)aminomethane, and deionized water are added to a reaction vessel. The reaction vessel is set to a temperature of 50°C and a rotation speed of 500 rpm. The mixture is stirred at a constant temperature for 50 min. After cooling to room temperature, dopamine hydrochloride is added to the reaction vessel, and the mixture is stirred for another 15 min. The resulting product is added to a centrifuge and centrifuged at 7000 rpm for 11 min. The precipitate is collected and then washed four times with ethanol and deionized water by stirring. The resulting product is added to a vacuum drying oven and dried at 65°C for 7 h to obtain the additive.

[0056] The mass ratio of carbon nanotubes, tris(hydroxymethyl)aminomethane, and deionized water is 1:0.05:9, and the mass of dopamine hydrochloride is 7% of the mass of carbon nanotubes.

[0057] Step 3: Mix the mixture with the additives to obtain the reinforcing material.

[0058] Among them, T-31 is selected as the curing agent.

[0059] The flame retardant selected is dimethyl methyl phosphate.

[0060] A method for preparing an epoxy resin composite board for automobiles containing basalt fibers includes the following steps:

[0061] S1: Weigh out epoxy resin, curing agent, reinforcing agent, flame retardant and colorant as needed and add them to the mixing tank. Stir at 350 r / min for 40 min to obtain a mixture.

[0062] S2: Transfer the mixture to an open-type stirred tank, set the temperature to 60℃, the speed to 125r / min, and continue to stir at a constant temperature for 3.5h, stopping for 5min every 30min to obtain the mixture;

[0063] S3: Pour the mixture into a mold preheated to 80°C, cure it under 10MPa pressure for 4.5h, and then cool it to 55°C to demold, thus obtaining an epoxy resin composite board for automobiles containing basalt fiber.

[0064] Example 3:

[0065] An epoxy resin composite board for automobiles containing basalt fiber comprises the following raw materials in parts by weight: 80 parts epoxy resin, 8 parts curing agent, 6 parts reinforcing agent, 3 parts flame retardant, and 0.4 parts colorant.

[0066] The reinforcing material is prepared by the following method:

[0067] Step 1: Preparation of the mixture. The raw materials for the mixture include fiber material, graphene micro flakes, tetrabutyl titanate, hexagonal boron nitride, deionized water, terephthalic acid, and urea. Basalt flakes are selected as the raw material for the fiber material.

[0068] The method for preparing the mixture is as follows: Fiber material, graphene microsheets, tetrabutyl titanate, hexagonal boron nitride, and deionized water are added to a mixer, which is set to 400 rpm and stirred for 40 minutes. Then, polydiallyl dimethyl ammonium chloride is added to the mixer, and the mixer is set to 100 rpm and stirred for 4 hours. The resulting product is added to a centrifuge, which is set to 10,000 rpm and centrifuged for 10 minutes. The centrifuged product yields a solid, which is washed with deionized water to obtain a coarse material. This coarse material, terephthalic acid, and urine... The raw material was added to a reaction vessel, which was set to a temperature of 140℃ and a stirring speed of 200 rpm. The mixture was stirred at this constant temperature for 60 minutes. After cooling to room temperature, four times the mass of the raw material was added to the reaction vessel and stirred at 400 rpm for 20 minutes. The resulting product was then added to a centrifuge and centrifuged at 10,000 rpm for 10 minutes. The precipitate was obtained from the centrifugation process and washed with deionized water. The precipitate was then placed in an oven and dried at 100℃ for 2–4 hours to obtain a mixture.

[0069] The mass ratio of fiber material, graphene microsheets, tetrabutyl titanate, hexagonal boron nitride, and deionized water is 1:0.4:0.06:1.2:60, and the mass ratio of coarse material, terephthalic acid, and urea is 1:0.06:0.3.

[0070] The fiber material is prepared by the following method: basalt flakes are soaked in an aqueous solution containing a silane coupling agent with a mass concentration of 0.6% for 4 hours. After soaking, the basalt flakes are placed in an oven and dried at 120°C for 4 hours to obtain the base material. The base material, xylene, and nano-silica dispersion are added to a mixer and stirred at 80 rpm for 60 minutes. The resulting product is added to a centrifuge and centrifuged at 12000 rpm for 10 minutes. The resulting solids are washed with ethanol 6 times and then added to an oven and dried at 120°C for 4 hours to obtain the fiber material.

[0071] The silane coupling agent used is KH550, and the mass ratio of the base material, xylene, and nano silica dispersion is 1:12:0.07.

[0072] Step 2: Preparation of additives. The raw materials for additives include carbon nanotubes, tris(hydroxymethyl)aminomethane, deionized water, and dopamine hydrochloride. The mass of the additives is 20% of the mass of the mixture.

[0073] The method for preparing the additive is as follows: carbon nanotubes, tris(hydroxymethyl)aminomethane, and deionized water are added to a reaction vessel. The reaction vessel is set to a temperature of 60°C and a rotation speed of 600 rpm. The mixture is stirred at a constant temperature for 60 min. After cooling to room temperature, dopamine hydrochloride is added to the reaction vessel, and the mixture is stirred for another 20 min. The resulting product is added to a centrifuge and centrifuged at 8000 rpm for 12 min. The precipitate is collected and then washed five times with ethanol and deionized water by stirring. The resulting product is added to a vacuum drying oven and dried at 70°C for 8 h to obtain the additive.

[0074] The mass ratio of carbon nanotubes, tris(hydroxymethyl)aminomethane, and deionized water is 1:0.06:10, and the mass of dopamine hydrochloride is 8% of the mass of carbon nanotubes.

[0075] Step 3: Mix the mixture with the additives to obtain the reinforcing material.

[0076] Among them, T-31 is selected as the curing agent.

[0077] The flame retardant selected is dimethyl methyl phosphate.

[0078] A method for preparing an epoxy resin composite board for automobiles containing basalt fibers includes the following steps:

[0079] S1: Weigh out epoxy resin, curing agent, reinforcing agent, flame retardant and colorant as needed and add them to the mixing tank. Stir at 400 r / min for 50 min to obtain a mixture.

[0080] S2: Transfer the mixture to an open mixing vessel, set the temperature to 65℃, the speed to 150r / min, and continue constant temperature stirring for 4 hours, stopping for 5 minutes every 30 minutes of stirring to obtain the mixture;

[0081] S3: Pour the mixture into a mold preheated to 80°C, cure it under 10MPa pressure for 5 hours, and then cool it to 60°C to demold, thus obtaining an epoxy resin composite board for automobiles containing basalt fiber.

[0082] Comparative Example 1: The difference between this comparative example and Example 1 is that an equal amount of untreated basalt flakes is used to replace the reinforcing material in this comparative example.

[0083] Comparative Example 2 differs from Example 1 in that no additives are added during the preparation of the reinforcing material in this comparative example.

[0084] Comparative Example 3 differs from Example 1 in that graphene microsheets and hexagonal boron nitride are not added during the preparation of the reinforcing material in this comparative example.

[0085] Performance testing: Epoxy resin composite boards were prepared using the preparation methods of Examples 1-3 and Comparative Examples 1-3, and then made into 80mm×10mm×4mm cuboid samples for testing.

[0086] Tensile property test: The tensile strength, tensile modulus and elongation at break of the samples were determined using a universal testing machine in accordance with the GB / T 1040.2-2022 standard. The data obtained are recorded in Table 1.

[0087] Bending performance test: The bending strength was determined using a universal testing machine according to the GB / T 9341-2008 standard, and the data obtained are recorded in Table 1.

[0088] Impact toughness test: The standard GB / T 1843-2008 was adopted. A V-shaped notch with a depth of 2 mm was machined in the middle of the sample. The impact strength of the notch was measured using a cantilever beam impact testing machine. The data obtained are recorded in Table 1.

[0089] Corrosion resistance test: Following GB / T 10125-2021 standard, a salt spray test chamber was used. The test solution was a 5% sodium chloride solution with a pH of 6.5 and a temperature of 35℃. Continuous spraying was conducted for 500 hours. Following GB / T6461-2002 standard, visual inspection was performed on the sample surface to record defects such as blistering, cracking, powdering, peeling, or significant discoloration. The samples were then rated from 1 to 9, with 9 being the best. The data obtained are recorded in Table 2. Simultaneously, tensile strength tests were performed on the samples after the salt spray test, and the residual tensile strength was calculated. The strength retention rate was calculated and recorded in Table 2. The calculation formula is: Residual tensile strength / Initial tensile strength × 100%.

[0090] Table 1:

[0091]

[0092] Table 2:

[0093] Testing items Appearance rating after 500 hours of salt spray test Tensile strength retention rate after salt spray test (%) Example 1 Level 9 (Slight discoloration) 89 Example 2 Level 9 (Slight discoloration) 87 Example 3 Level 9 (Slight discoloration) 86 Comparative Example 1 Level 4 (obvious blistering and peeling) 60 Comparative Example 2 Level 7 (localized pitting, discoloration) 73 Comparative Example 3 Level 6 (Extensive discoloration) 75

[0094] Analysis of the data in the comparison table shows that the epoxy resin composite boards prepared by the methods of Examples 1-3 are superior to those of Comparative Examples 1-3 in both mechanical properties and corrosion resistance. Furthermore, all properties of Comparative Example 1, which does not contain reinforcing material, are significantly reduced, proving that "reinforcing material" is the cornerstone of the overall performance improvement.

[0095] Further analysis revealed that in Comparative Example 1, which lacked reinforcing material, all mechanical and corrosion resistance properties experienced a precipitous decline. This was mainly due to the absence of reinforcing material. The performance collapse of the traditional epoxy resin and basalt flake composite material, which reverted to its basic structure, also indicated that the lack of nanoscale reinforcement and crack deflection effect provided by graphene microflakes and hexagonal boron nitride, as well as the three-dimensional network support structure constructed by polydopamine-modified carbon nanotubes, meant that the material could not effectively resist external forces and prevent crack propagation. Furthermore, the poor interfacial bonding between ordinary basalt flakes without complex surface treatment and the epoxy resin matrix made them prone to becoming stress concentration points and channels for corrosive media penetration.

[0096] In Comparative Example 2, which lacked the additive, the impact toughness and corrosion resistance decreased significantly. This is because the lack of additive resulted in the absence of polydopamine coating modification on the carbon nanotubes. Polydopamine contains abundant functional groups, which can improve the interfacial compatibility between carbon nanotubes and epoxy resin, prevent agglomeration, and make them uniformly dispersed to form an effective three-dimensional network. This network can consume a large amount of crack propagation energy, thereby promoting the improvement of material toughness. In addition, polydopamine itself has strong adhesion and certain barrier properties. Its absence makes the interfacial area more susceptible to corrosion by corrosive media.

[0097] In Comparative Example 3, which lacks graphene microflakes and hexagonal boron nitride, the overall performance is significantly reduced. This is because when graphene microflakes and hexagonal boron nitride are uniformly dispersed in the matrix, they can effectively bear the load, improve the bending strength and modulus of the material, and form tortuous paths in the composite material, effectively blocking the penetration of corrosive media such as water, oxygen, and chloride ions. When they are missing, they will create fast channels required for media diffusion, accelerating internal corrosion.

[0098] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above 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 one or more embodiments or examples.

[0099] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. An epoxy resin composite board for automobiles containing basalt fibers, characterized in that: The raw materials include the following parts by weight: 50-80 parts epoxy resin, 4-8 parts curing agent, 3-6 parts reinforcing agent, 1-3 parts flame retardant, and 0.2-0.4 parts colorant; The reinforcing material is prepared by the following method: Step 1: Preparation of the mixture. The raw materials of the mixture include fiber material, graphene micro flakes, tetrabutyl titanate, hexagonal boron nitride, deionized water, terephthalic acid, and urea. The fiber material is selected from basalt flakes. The fiber material is prepared by the following method: basalt flakes are soaked in an aqueous solution containing a silane coupling agent with a mass concentration of 0.3-0.6% for 2-4 hours. After soaking, the basalt flakes are placed in an oven and dried at 80-120°C for 2-4 hours to obtain a base material. The base material, xylene, and nano-silica dispersion are added to a mixer and stirred at 60-80 rpm for 40-60 minutes. The resulting product is added to a centrifuge and centrifuged at 10000-12000 rpm for 6-10 minutes. The resulting solids are washed with ethanol 4-6 times and then added to an oven and dried at 100-120°C for 2-4 hours to obtain the fiber material. KH550 is selected as the silane coupling agent. Step 2: Preparation of additives. The raw materials for additives include carbon nanotubes, tris(hydroxymethyl)aminomethane, deionized water, and dopamine hydrochloride. The mass of the additives is 10-20% of the mass of the mixture. Step 3: Mix the mixture with the additives to obtain the reinforcing material.

2. The basalt fiber-containing epoxy resin composite board for automobiles according to claim 1, characterized in that, The method for preparing the mixture is as follows: Fiber material, graphene microsheets, tetrabutyl titanate, hexagonal boron nitride, and deionized water are added to a mixer. The mixer is set to 200-400 rpm and stirred for 20-40 minutes. Then, polydiallyl dimethyl ammonium chloride is added to the mixer, and the mixer is set to 60-100 rpm and stirred for 2-4 hours. The resulting product is added to a centrifuge and centrifuged at 8000-10000 rpm for 6-10 minutes. The centrifuged product yields a solid. The solid is washed with deionized water to obtain a coarse material. The coarse material, terephthalic acid, and urea are added to a reaction vessel. In the process, the reactor temperature is set at 120-140℃, the stirring speed is 100-200 rpm, and the constant temperature stirring is carried out for 40-60 minutes. After cooling to room temperature, 2-4 times the mass of the coarse material is added to the reactor, and the stirring is carried out at 200-400 rpm for 10-20 minutes. The resulting product is added to a centrifuge and centrifuged at 8000-10000 rpm for 6-10 minutes. The precipitate obtained from the centrifugation is washed with deionized water and then sent to an oven and dried at 80-100℃ for 2-4 hours to obtain a mixture.

3. The basalt fiber-containing epoxy resin composite board for automobiles according to claim 2, characterized in that, The mass ratio of fiber material, graphene microsheets, tetrabutyl titanate, hexagonal boron nitride, and deionized water is 1:(0.2-0.4):(0.04-0.06):(0.8-1.2):(40-60), and the mass ratio of coarse material, terephthalic acid, and urea is 1:(0.04-0.06):(0.2-0.3).

4. The basalt fiber-containing epoxy resin composite board for automobiles according to claim 1, characterized in that, The mass ratio of the base material, xylene, and nano-silica dispersion is 1:(10-12):(0.05-0.07).

5. The basalt fiber-containing epoxy resin composite board for automobiles according to claim 1, characterized in that, The method for preparing the additive is as follows: carbon nanotubes, tris(hydroxymethyl)aminomethane, and deionized water are added to a reaction vessel. The reaction vessel is set at a temperature of 40–60°C and a rotation speed of 400–600 rpm. The mixture is stirred at a constant temperature for 40–60 min. After cooling to room temperature, dopamine hydrochloride is added to the reaction vessel, and the mixture is stirred for another 10–20 min. The resulting product is then added to a centrifuge and centrifuged at 6000–8000 rpm for 10–12 min. The precipitated product is collected and then washed 3–5 times alternately with ethanol and deionized water by stirring. The resulting product is then placed in a vacuum drying oven and dried at 60–70°C for 6–8 h to obtain the additive.

6. The basalt fiber-containing epoxy resin composite board for automobiles according to claim 5, characterized in that, The mass ratio of carbon nanotubes, tris(hydroxymethyl)aminomethane, and deionized water is 1:(0.04–0.06):(8–10), and the mass of dopamine hydrochloride is 6–8% of the mass of carbon nanotubes.

7. The basalt fiber-containing epoxy resin composite board for automobiles according to claim 1, characterized in that, The curing agent used is T-31.

8. The basalt fiber-containing epoxy resin composite board for automobiles according to claim 1, characterized in that, The flame retardant is dimethyl methyl phosphate.

9. The method for preparing the basalt fiber-containing epoxy resin composite board for automobiles according to any one of claims 1 to 8, characterized in that, Includes the following steps: S1: Weigh out epoxy resin, curing agent, reinforcing agent, flame retardant and colorant as needed and add them to the mixing tank. Stir at 300-400 r / min for 30-50 min to obtain a mixture. S2: Transfer the mixture to an open mixing vessel, set the temperature to 55-65℃, the speed to 100-150r / min, and continue constant temperature stirring for 3-4 hours, stopping for 5 minutes every 30 minutes of stirring to obtain the mixture; S3: Pour the mixture into a mold preheated to 80°C, cure it under 10MPa pressure for 4-5 hours, and then cool it to 50-60°C to demold it, thus obtaining an epoxy resin composite board for automobiles containing basalt fiber.

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