Lightweight corrosion-resistant material for automobile underbody shields and method for producing the same

Abstract

The application discloses a light corrosion-resistant material for an automobile underbody shield and a preparation method thereof. The light corrosion-resistant material is prepared by compounding an aramid-glass-carbon fiber composite layer and an LWRT plate layer in an intra-layer / inter-layer hybrid manner. The aramid-glass-carbon fiber composite layer is woven by aramid fibers, glass fibers and carbon fibers in a warp-knitting four-axial structure. The light corrosion-resistant material is prepared by compounding the LWRT plate layer and the aramid-glass-carbon fiber composite layer in the intra-layer / inter-layer hybrid manner, so that the light corrosion-resistant material is lightweight while the structural strength of the light corrosion-resistant material is ensured.

Description

Technical Field

[0001] This invention relates to the field of new materials technology, specifically to a lightweight corrosion-resistant material for automotive underbody protection panels and its preparation method. Background Technology

[0002] Car underbody protection plates, also known as car skid plates, are engine protection devices that are custom-designed around the original mounting holes of the vehicle model and the engine frame. Their design concept is primarily to prevent damage to the engine caused by impacts from protruding stones on the road surface, and secondly to prevent mud and sewage from entering the engine compartment during driving, which could lead to engine failure. Through the original chassis 3D design, they provide the most comprehensive protection for the engine.

[0003] Car underbody protection plates effectively protect the engine from impacts and mud splatter when driving on uneven or muddy roads, minimizing the risk of engine damage and breakdowns due to external factors. However, commonly available underbody protection plates are typically made of metal materials such as iron, which can rust over time, hindering vehicle operation. Furthermore, loose mounting bolts or impacts with the oil pan can cause significant noise, and the weight of metal underbody protection plates increases the overall vehicle weight. Therefore, a new type of car underbody protection plate is needed to address these issues. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention provides a lightweight corrosion-resistant material for automotive underbody protection panels and its preparation method.

[0005] The technical solution of the present invention is: a lightweight corrosion-resistant material for automotive underbody protection plates, wherein the lightweight corrosion-resistant material is made by combining an aramid-glass-carbon fiber composite layer with an LWRT plate layer in an intralayer / interlayer hybrid manner, and the aramid-glass-carbon fiber composite layer and the LWRT plate layer are bonded together with a composite epoxy resin; wherein the aramid-glass-carbon fiber composite layer is woven from aramid fibers, glass fibers and carbon fibers in a warp-knitted four-axis structure.

[0006] Furthermore, in the warp-knitted four-axis structure of the aramid-glass-carbon fiber composite layer, the carbon fiber is warp-knitted at 45° and -45°, and the aramid fiber and glass fiber are warp-knitted at 0° and 90°. The matrix of the aramid-glass-carbon fiber composite layer is a composite epoxy resin.

[0007] Description: The aramid-glass-carbon fiber composite layer is structurally designed using a warp-knitted four-axis structure. In this structure, the aramid and glass fiber bundles are arranged in parallel, and the binding yarns are also arranged in parallel. At the same time, the carbon fibers are interwoven to form a cross-shaped structure. After impregnation and curing with composite epoxy resin, a high-performance composite material can be obtained. This allows the aramid-glass-carbon fiber composite layer to withstand greater stress when subjected to impact. This structural design enables it to have high tensile strength and elastic modulus, thus endowing the aramid-glass-carbon fiber composite layer with excellent strength and stability.

[0008] Furthermore, in the warp-knitted four-axis structure of the aramid-glass-carbon fiber composite layer, 10-20 tex nylon low-elasticity yarn or polyester low-elasticity yarn is used as the binding yarn.

[0009] Note: Due to the low elasticity of nylon or polyester low elastic yarn, it has good dimensional and shape stability. When the aramid-glass-carbon fiber composite layer is woven through a warp-knitted four-axis structure, the low elastic yarn can help maintain the shape of the product, reduce the possibility of deformation and twisting, and the low elastic yarn is easy to process, which can improve the operability and flexibility.

[0010] Among them, nylon low elastic yarn has excellent wear resistance and the ability to stretch and recover within a certain range. This allows nylon low elastic yarn to maintain a certain elasticity while providing a stable shape, which can improve the impact resistance of aramid-glass-carbon fiber composite layer.

[0011] Polyester low-elasticity yarn has excellent breaking strength and elastic modulus, with its strength far exceeding that of other natural and synthetic fibers. It also has good heat resistance and thermal stability, and its abrasion resistance is second only to nylon. Furthermore, polyester low-elasticity yarn can resist the erosion of bleach, hydrocarbons, ketones, petroleum products and inorganic acids, is resistant to dilute alkalis, and is not afraid of mildew, enabling it to maintain stable performance in a variety of environments.

[0012] Furthermore, the carbon fiber needs to be etched and carbamoyl hydrazine containing amino groups is attached to the etched carbon fiber in multiple stages.

[0013] Note: Because the carbon fiber surface lacks active functional groups at the interface between carbon fiber and composite epoxy resin, it cannot form a stable and high-strength interface with the composite epoxy resin, and the composite epoxy resin cannot provide good interfacial bonding force.

[0014] Surface treatment of carbon fibers can effectively increase the active functional groups on the carbon fiber surface, which helps the adhesion of carbamoyl hydrazine containing amino groups and improves the overall performance and strength of the aramid-glass-carbon fiber composite layer.

[0015] Furthermore, the method for etching the carbon fiber and then attaching carbamoyl hydrazine containing amino groups to the etched carbon fiber in multiple stages is as follows:

[0016] 1) Clean the carbon fiber, then immerse the cleaned carbon fiber in nitric acid solution for 1-2 minutes, rinse the carbon fiber several times with pure water, and dry it to obtain the etched carbon fiber.

[0017] 2) The etched carbon fiber is immersed in an aqueous solution of carbamoyl hydrazine, then the carbon fiber is taken out, cleaned and dried, and then immersed in the aqueous solution of carbamoyl hydrazine again. This process is repeated several times, with each immersion time being 10 to 15 minutes, to obtain carbon fiber after multi-stage adhesion treatment.

[0018] Explanation: Soaking carbon fibers in nitric acid solution can oxidize the carbon fiber surface and increase the depth of the grooves on the carbon fiber surface without damaging the carbon fiber matrix. After nitric acid treatment, the carbon fiber surface will have more oxygen- and nitrogen-containing functional groups, and the larger microcrystals on the outer layer of the carbon fiber will be corroded by the acid solution and gradually transform into microcrystals on the subsurface layer, which will help the adhesion of carbamoyl hydrazine containing amino groups.

[0019] By repeatedly immersing the etched carbon fibers in an aqueous solution of carbamoyl hydrazine, the carbamoyl hydrazine containing amino groups can better adhere to the carbon fibers, thereby improving the performance of the carbon fibers. Furthermore, repeated immersion helps to improve the interfacial bonding between different materials and enhances the interfacial strength between the treated carbon fibers and the composite epoxy resin.

[0020] Furthermore, the preparation method of the composite epoxy resin is as follows: epoxy resin and curing agent are mixed at a mass ratio of 100:30, and nano carbon balls accounting for 2-6% of the total mass of epoxy resin and curing agent are added and mixed evenly.

[0021] Note: On the one hand, nano-carbon spheres can increase the viscosity of composite epoxy resin. On the other hand, after introducing a certain number of nano-carbon spheres, excessive addition can easily lead to the composite epoxy resin failing to form a stable interface with the fiber. Adding a small amount ensures the good performance of the composite epoxy resin and enables the overall aramid-glass-carbon fiber composite layer to have higher service strength.

[0022] Furthermore, the linear density of the aramid fiber filament bundle, the linear density of the glass fiber filament bundle, and the linear density of the carbon fiber filament bundle are all 300-400 tex.

[0023] Note: When aramid-glass-carbon fiber composite layers are warp-knitted in a four-axis structure using aramid fibers, glass fibers, and carbon fibers, the linear density of the filament bundles determines to a certain extent the number of points, lines, and grids per unit area. This plays a crucial role in the overall performance of the aramid-glass-carbon fiber composite layer. By using a linear density of 300–400 tex filament bundles, the aramid-glass-carbon fiber composite layer can achieve good tensile strength and impact resistance.

[0024] This invention also provides a method for preparing a lightweight corrosion-resistant material for automotive underbody protection panels, comprising the following steps based on the aforementioned lightweight corrosion-resistant material:

[0025] S1. Preparation of aramid-glass-carbon fiber composite layer:

[0026] Aramid fiber filament bundles, glass fiber filament bundles, and carbon fiber filament bundles were selected in a 1:1:2 ratio. An intralayer hybrid was woven using a warp-knitted four-axis structure. Composite epoxy resin was uniformly coated onto the upper surface of the intralayer hybrid at a volume ratio of 3:2. A vacuum bag was then attached to the intralayer hybrid, and the hybrid was pressurized for 2 hours using the pressure difference generated by vacuuming, achieving a vacuum degree of 1×10⁻⁶. -2 ~1×10 -1 Pa, so that the composite epoxy resin can be uniformly penetrated from the upper surface to the lower surface of the hybrid in the layer until it is completely impregnated. After the penetration is complete, it is placed at room temperature for 24 hours to obtain an aramid-glass-carbon fiber composite layer with a thickness of 1 to 3 mm.

[0027] S2. Preparation of lightweight corrosion-resistant materials:

[0028] n aramid-glass-carbon fiber composite layers with a thickness of 1-3 mm and n-1 LWRT plates with a thickness of 1 mm are stacked in an intra-layer / inter-layer hybrid manner, so that both the top and bottom sides are aramid-glass-carbon fiber composite layers. During the stacking process, a composite epoxy resin with a thickness of 0.5-1 mm is applied between each aramid-glass-carbon fiber composite layer and the LWRT plate. Then, a vacuum bag is attached to the intra-layer hybrid, and the intra-layer hybrid is pressurized for 2 hours by the pressure difference generated by vacuuming, with a vacuum degree of 1×10^-2 to 1×10^-1 Pa, so that each aramid-glass-carbon fiber composite layer and the LWRT plate are pressed together. After being placed at room temperature for 24 hours, a lightweight corrosion-resistant material is obtained.

[0029] Furthermore, the aramid-glass-carbon fiber composite layers on both sides of the lightweight corrosion-resistant material are coated with anti-corrosion coatings.

[0030] Note: By spraying anti-corrosion coatings onto the outer aramid-glass-carbon fiber composite layers on both sides of a lightweight corrosion-resistant material, the corrosion resistance can be enhanced on the basis of the aramid-glass-carbon fiber composite layer's corrosion resistance, thus giving the lightweight corrosion-resistant material better performance.

[0031] The beneficial effects of this invention are:

[0032] (1) The lightweight corrosion-resistant material used in the present invention for automotive underbody protection plates is made by using LWRT plate layers and aramid-glass-carbon fiber composite layers in an intralayer / interlayer hybrid manner, which can make the lightweight corrosion-resistant material lighter while ensuring the structural strength of the lightweight corrosion-resistant material.

[0033] (2) The present invention designs the aramid-glass-carbon fiber composite layer through a warp-knitted four-axis structure, which enables the aramid-glass-carbon fiber composite layer to withstand greater stress when subjected to impact. This structural design enables it to have high tensile strength and elastic modulus, thereby giving the aramid-glass-carbon fiber composite layer excellent strength and stability.

[0034] (3) The present invention can improve the performance of carbon fiber by treating carbon fiber. Multiple impregnation helps to improve the interfacial bonding between carbon fiber and different materials, thereby enhancing the interfacial strength between the treated carbon fiber and the composite epoxy resin. Attached Figure Description

[0035] Figure 1 This is a schematic diagram of the simulated structure of the lightweight corrosion-resistant material of this invention.

[0036] Figure 2 This is a schematic diagram of the simulated four-axis warp-knitted structure of the aramid-glass-carbon fiber composite layer of the present invention.

[0037] Figure 3 This is a flowchart of the method for synthesizing lightweight corrosion-resistant materials according to the present invention.

[0038] Figure 4 This is a schematic diagram of the simulated structure of the lightweight corrosion-resistant material of Embodiment 22 of the present invention.

[0039] Figure 5 This is a schematic diagram of the simulated structure of the lightweight corrosion-resistant material of Embodiment 23 of the present invention. Detailed Implementation

[0040] The present invention will now be described in more detail with reference to specific embodiments, so as to better demonstrate the advantages of the present invention.

[0041] Example 1: A lightweight, corrosion-resistant material for automotive underbody protection panels, such as... Figure 1As shown, the lightweight corrosion-resistant material is made by combining three 3mm aramid-glass-carbon fiber composite layers with two 1mm LWRT plates in an intralayer / interlayer hybrid manner, so that both the top and bottom sides are aramid-glass-carbon fiber composite layers. The aramid-glass-carbon fiber composite layers and LWRT plates are bonded together with composite epoxy resin, which is obtained by mixing epoxy resin and curing agent in a mass ratio of 100:30.

[0042] It is understandable that LWRT sheets are used to reduce production costs. The aramid-glass-carbon fiber composite layer has strong corrosion resistance due to the use of epoxy resin. If production costs are not a concern, the entire aramid-glass-carbon fiber composite layer can be used to make a lightweight and corrosion-resistant material.

[0043] The aramid-glass-carbon fiber composite layer is composed of aramid fibers with a linear density of 380 tex, glass fibers with a linear density of 320 tex, and carbon fibers with a linear density of 320 tex. Figure 2 As shown, it is woven using a warp-knitted four-axis structure of carbon fiber, carbon fiber {45°, -45° biaxial warp knitting}, aramid fiber, and glass fiber {0°, 90°} biaxial warp knitting, and uses 10tex nylon low-elastic yarn as binding yarn.

[0044] The LWRT board layer uses commercially available LWRT sheets, which use PP fiber as the matrix fiber. The glass fiber and PP fiber are uniformly mixed and bundled together through processes such as unpacking, carding, web formation, needle punching, and hot pressing, resulting in a density of 2000 g / m². 2 .

[0045] Experimental design: Referring to ASTM D3039 "Standard Test Method for Tensile Properties of Polymer-Based Composites", the tensile properties of the aramid-glass-carbon fiber composite layer were tested in four directions {45°, -45°, 0°, 90°}.

[0046] A aramid-glass-carbon fiber composite layer measuring 300mm in length and 300mm in width was cut and designated as test sample 1. Glass fiber boards of the same size (45° and -45° biaxial warp-knitted) were set up as a control and designated as control sample 1. Both groups of samples were edge-reinforced and tested on an MTS testing machine. Each group of samples was tested three times, and the average value was taken. The results are shown in Table 1 below.

[0047] Table 1 Tensile property test data of the two groups of samples

[0048]

[0049]

[0050] As can be seen from Table 1 above, the tensile strength and tensile modulus of the aramid-glass-carbon fiber composite layer are significantly better than those of the glass fiber board of control sample 1. By adopting the warp knitting four-axis structure weaving technology, aramid fiber, glass fiber and carbon fiber are organically combined, which can significantly improve the performance of the prepared composite material.

[0051] Meanwhile, control sample 1, which uses 45° and -45° biaxial warp knitting, showed a significant decrease in tensile strength when stretched in the 0° and 90° directions. In contrast, this application incorporates aramid fibers and glass fibers in the 0° and 90° directions, which strengthens the aramid-glass-carbon fiber composite layer system. As can be seen from the results in Table 1, the aramid-glass-carbon fiber composite layer did not show a significant decrease in tensile strength in the 0° and 90° directions. Therefore, the aramid-glass-carbon fiber composite layer prepared using Example 1 has superior tensile properties and better stability in use.

[0052] Furthermore, refer to ASTM D7136, "Test method for measuring resistance to drop hammer impact damage of fiber-reinforced polymer matrix composites";

[0053] Using the same dimensions as the tensile test, aramid-glass-carbon fiber composite layers measuring 300mm in length and 300mm in width were cut and designated as test sample 1. Glass fiber boards of the same dimensions (45° and -45° biaxial warp-knitted) were set up as controls and designated as control sample 1. The samples were tested using a drop weight impact tester, with each group of samples tested three times and the average value taken. The results are shown in Table 2 below.

[0054] Table 2 Impact test data for the two groups of samples

[0055] project Test sample 1 Control sample 1 Maximum impact load / N 8327.78 5120.43

[0056] As can be seen from Table 2 above, the impact resistance of the aramid-glass-carbon fiber composite layer is significantly better than that of the glass fiber board of control sample 1, and the maximum impact load is increased by about 62.6% compared with the glass fiber board of control sample 1. It can be seen that by using warp knitting four-axis structure weaving technology to organically combine aramid fiber, glass fiber and carbon fiber, the impact resistance of the prepared composite material can be significantly improved.

[0057] Example 2: The difference between this example and Example 1 is that the aramid-glass-carbon fiber composite layer is composed of aramid fibers with a filament bundle linear density of 300 tex, glass fibers with a filament bundle linear density of 300 tex, and carbon fibers with a filament bundle linear density of 300 tex.

[0058] Example 3: The difference between this example and Example 1 is that the aramid-glass-carbon fiber composite layer is composed of aramid fibers with a filament bundle linear density of 400 tex, glass fibers with a filament bundle linear density of 400 tex, and carbon fibers with a filament bundle linear density of 400 tex.

[0059] Example 4: The difference between this example and Example 1 is that 20tex nylon low-elasticity yarn is used as the binding yarn.

[0060] Example 5: The difference between this example and Example 1 is that 10tex polyester low elastic yarn is used as the binding yarn.

[0061] To verify the performance of the aramid-glass-carbon fiber composite layers prepared in Examples 2-5, since the main consideration for automotive underbody protection is impact resistance, the impact test method of Example 1 was adopted, and each example was designated as test sample 2, test sample 3, test sample 4, and test sample 5, respectively. The results are shown in Table 3 below:

[0062] Table 3 Impact test data for four groups of samples

[0063] project Test sample 2 Test sample 3 Test sample 4 Test sample 5 Maximum impact load / N 7924.45 7864.12 8273.23 8303.47

[0064] As can be seen from Table 3 above, adjusting the linear density of the aramid fiber, glass fiber, and carbon fiber filament bundles used in the aramid-glass-carbon fiber composite layer has a certain impact on the impact resistance of the prepared aramid-glass-carbon fiber composite layer. Among them, the effect is relatively optimal when using 380tex aramid fiber, 320tex glass fiber, and 320tex carbon fiber as in Example 1.

[0065] Example 6: This example differs from Example 1 in that the carbon fiber needs to be etched, and carbamoyl hydrazine containing amino groups is attached to the etched carbon fiber in multiple stages; wherein, the method for etching the carbon fiber and attaching carbamoyl hydrazine containing amino groups to the etched carbon fiber in multiple stages is as follows:

[0066] 1) Clean the carbon fiber with pure water, dry it, immerse the cleaned carbon fiber in a 30% nitric acid solution for 90 seconds, rinse the carbon fiber with pure water several times, and dry it to obtain the etched carbon fiber.

[0067] 2) The etched carbon fiber was immersed in a 20% carbamoyl hydrazine aqueous solution. The carbon fiber was then removed, washed with pure water, and dried at 45°C for 30 seconds. It was then immersed in a 20% carbamoyl hydrazine aqueous solution for five times, with each immersion time being 12 minutes, to obtain carbon fiber after multi-stage adhesion treatment.

[0068] Understandably, to ensure the concentration of carbamoyl hydrazine in the aqueous solution, the concentration of the current aqueous solution can be readjusted each time it is dried, or multiple sets of aqueous solutions of carbamoyl hydrazine can be used.

[0069] To verify the performance of the aramid-glass-carbon fiber composite layer prepared in Example 6, the test method of Example 1 was used for testing, and each example was recorded as test sample 6. The results are shown in Tables 4 and 5 below:

[0070] Table 4 Tensile property test data of the two groups of samples

[0071]

[0072] As can be seen from Table 4 above, the tensile strength in the 0° and 90° directions was significantly improved after carbon fiber treatment. This shows that carbon fiber treatment can significantly improve the bonding between carbon fiber and composite epoxy resin, so that the prepared aramid-glass-carbon fiber composite layer has excellent tensile properties in any angle direction, effectively solving the influence of tensile angle on material properties.

[0073] Table 5 Impact test data for the two groups of samples

[0074] project Test sample 1 Test sample 6 Maximum impact load / N 8327.78 8947.59

[0075] As can be seen from Table 5 above, the treatment of carbon fiber not only optimized the tensile strength in the 0° and 90° directions, but also improved the overall impact resistance of the aramid-glass-carbon fiber composite layer due to the enhanced interfacial bonding strength between the carbon fiber and the composite epoxy resin. By using the treated carbon fiber, the aramid-glass-carbon fiber composite layer can have better impact resistance.

[0076] Example 7: The difference between this example and Example 6 is that the cleaned carbon fiber is immersed in a 30% nitric acid solution for 1 minute.

[0077] Example 8: The difference between this example and Example 6 is that the cleaned carbon fiber is immersed in a 30% nitric acid solution for 2 minutes.

[0078] Example 9: The difference between this example and Example 6 is that step 2) is repeated to immerse the etched carbon fiber in a 20% carbamoyl hydrazine aqueous solution three times.

[0079] Example 10: This example differs from Example 6 in that step 2) is repeated to immerse the etched carbon fiber in a 20% carbamoyl hydrazine aqueous solution six times.

[0080] Example 11: The difference between this example and Example 6 is that the soaking time for a single soaking is 10 minutes.

[0081] Example 12: The difference between this example and Example 6 is that the soaking time for a single soaking is 15 minutes.

[0082] To verify the performance of the aramid-glass-carbon fiber composite layers prepared in Examples 7-12, since carbon fiber treatment significantly affects the tensile strength in the 0° and 90° directions, the tensile testing method of Example 1 was used. The samples for each example were designated as test sample 7, test sample 8, test sample 9, test sample 10, test sample 11, and test sample 12, respectively. The results are shown in Table 6 below.

[0083] Table 6 Tensile property test data of six groups of samples

[0084] project Test sample 7 Test sample 8 Test sample 9 0° / 90° 381.25 / 383.42 384.67 / 385.91 380.37 / 379.98 project Test sample 10 Test sample 11 Test sample 12 0° / 90° 390.68 / 390.96 379.58 / 379.32 389.89 / 390.78

[0085] As can be seen from Table 6 above, different immersion times have a certain impact on the tensile strength of the prepared test samples in the 0° and 90° directions. Excessive immersion time may have a certain impact on carbon fibers. Therefore, the immersion time of Example 6 is relatively optimal.

[0086] Meanwhile, by using different numbers of treatments and single impregnation times for carbon fibers, neither test sample 10 nor test sample 12 showed a significant increase in tensile strength. This may be because the carbon fiber sites were sufficiently coated with carbamoyl hydrazine in the treatment method of Example 6. Therefore, from the perspective of economy, the number of treatments and single impregnation time in Example 6 are relatively optimal.

[0087] Example 13: A method for preparing a lightweight corrosion-resistant material for automotive underbody protection panels, based on the lightweight corrosion-resistant material of Example 1, such as... Figure 3 As shown, it includes the following steps:

[0088] S1. Preparation of aramid-glass-carbon fiber composite layer:

[0089] Aramid fiber filament bundles, glass fiber filament bundles, and carbon fiber filament bundles were selected in a 1:1:2 ratio and woven using a warp-knitted four-axis structure to obtain an intralayer hybrid. A composite epoxy resin, obtained by mixing epoxy resin and curing agent at a mass ratio of 100:30, was uniformly applied to the upper surface of the intralayer hybrid at a volume ratio of 3:2. A vacuum bag was then attached to the intralayer hybrid, and the hybrid was pressurized for 2 hours using the pressure difference generated by vacuuming, with a vacuum degree of 1×10⁻⁶. -2Pa, so that the composite epoxy resin can be uniformly penetrated from the upper surface to the lower surface of the hybrid in the layer until it is completely impregnated. After the penetration is complete, it is placed at room temperature for 24 hours to obtain an aramid-glass-carbon fiber composite layer with a thickness of 3 mm.

[0090] S2. Preparation of lightweight corrosion-resistant materials:

[0091] Three 3mm thick aramid-glass-carbon fiber composite layers and two 1mm thick LWRT boards are stacked using an intra-layer / inter-layer hybrid method (specifically, as follows). Figure 1 As shown, aramid-glass-carbon fiber composite layers and LWRT plates are stacked alternately, with a total of 5 layers. Both the top and bottom sides are composed of aramid-glass-carbon fiber composite layers. During the stacking process, a 0.7mm thick composite epoxy resin is applied between the aramid-glass-carbon fiber composite layers and the LWRT plates. The composite epoxy resin is obtained by mixing epoxy resin and curing agent at a mass ratio of 100:30. A vacuum bag is then attached to the hybrid layer, and the hybrid layer is pressurized for 2 hours using the pressure difference generated by vacuuming, with a vacuum degree of 1×10⁻⁶. -2 Pa is used to press the various aramid-glass-carbon fiber composite layers and LWRT plates together, and after being placed at room temperature for 24 hours, a lightweight and corrosion-resistant material with a thickness of about 1.4 cm is obtained.

[0092] Example 14: Based on Example 13, this example involves spraying a 0.5mm thick anti-corrosion coating onto both outer aramid-glass-carbon fiber composite layers of the lightweight corrosion-resistant material. The anti-corrosion coating is a commercially available acrylic coating. Acrylic coatings have good weather resistance and corrosion resistance, as well as excellent color retention and decorative effect, which can enhance the aesthetics of the lightweight corrosion-resistant material. This allows the material to be used in other automotive material panels. It is understood that the application is not limited to this type of coating; polyurethane coatings, etc., can also be used. Spraying can be performed according to actual application requirements.

[0093] Example 15: The difference between this example and Example 13 is that in step S1, the amount of composite epoxy resin added is such that after the infiltration is complete and the mixture is left at room temperature for 24 hours, an aramid-glass-carbon fiber composite layer with a thickness of 2 mm is obtained.

[0094] Example 16: The difference between this example and Example 13 is that in step S1, the amount of composite epoxy resin added is such that after the infiltration is complete and the mixture is left at room temperature for 24 hours, an aramid-glass-carbon fiber composite layer with a thickness of 1 mm is obtained.

[0095] Example 17: The difference between this example and Example 13 is that, in step S2, a composite epoxy resin with a thickness of 1 mm is applied between the aramid-glass-carbon fiber composite layer and the LWRT plate layer.

[0096] Example 18: The difference between this example and Example 13 is that, in step S2, a composite epoxy resin with a thickness of 0.5 mm is applied between the aramid-glass-carbon fiber composite layer and the LWRT plate layer.

[0097] Example 19: The difference between this example and Example 13 is that in steps S1 and S2, the preparation method of the composite epoxy resin is as follows: epoxy resin and curing agent are mixed in a mass ratio of 100:30, and nano carbon balls accounting for 4.5% of the total mass of epoxy resin and curing agent are added and mixed evenly.

[0098] Example 20: This example differs from Example 13 in that the proportion of carbon nanospheres in the epoxy resin and curing agent is 2%.

[0099] Example 21: This example differs from Example 13 in that the proportion of carbon nanospheres in the epoxy resin and curing agent is 6%.

[0100] Example 22: This example differs from Example 13 in that, as Figure 4 As shown, four aramid-glass-carbon fiber composite layers with a thickness of 3 mm and three LWRT plates with a thickness of 1 mm are stacked in an intra-layer / inter-layer hybrid manner, with a total of 7 layers.

[0101] Example 23: This example differs from Example 13 in that, as Figure 5 As shown, five aramid-glass-carbon fiber composite layers with a thickness of 3 mm and four LWRT plates with a thickness of 1 mm are stacked in an intra-layer / inter-layer hybrid manner, with a total of 9 layers.

[0102] It is understood that both Example 22 and this example use more stacked layers to prepare lightweight corrosion-resistant materials. Theoretically, as the number of layers is continuously stacked, its strength will be higher, but the thickness and weight will increase accordingly. The choice can be made according to actual needs.

[0103] To verify the performance of the lightweight corrosion-resistant materials prepared in Examples 13-23, since the impact protection effect of automotive underbody panels is mainly considered, the impact test method of Example 1 was adopted, and the samples for each example were respectively labeled as test sample 13, test sample 14, test sample 15, test sample 16, test sample 17, test sample 18, test sample 19, test sample 20, test sample 21, test sample 22, and test sample 23. The results are shown in Table 7 below:

[0104] Table 7 Impact test data of eleven groups of samples

[0105] project Test sample 13 Test sample 14 Test sample 15 Test sample 16 Maximum impact load / N 31374.36 31183.21 29875.56 31987.83 project Test sample 17 Test sample 18 Test sample 19 Test sample 20 Maximum impact load / N 30865.27 31738.46 33529.67 32879.86 project Test sample 21 Test sample 22 Test sample 23 / Maximum impact load / N 33217.64 35472.91 38742.37 /

[0106] As can be seen from Table 7 above, using different total stacking layers has a significant impact on the impact resistance of lightweight corrosion-resistant materials, but the total weight also increases accordingly. Furthermore, a comparison of the amount of composite epoxy resin shows that using a larger coating amount improves the impact resistance of lightweight corrosion-resistant materials, but the total weight also increases with the increase in thickness. Therefore, it is necessary to select the appropriate amount based on actual production needs.

[0107] Furthermore, the test sample 14 was coated with an anti-corrosion coating to enhance the corrosion resistance of the outer aramid-glass-carbon fiber composite layer. The surface of the test sample 14 was continuously sprayed with 30% nitric acid solution until obvious corrosion damage appeared on the surface of the aramid-glass-carbon fiber composite layer. The time to reach this point was recorded. The test was repeated 5 times. Compared with the test sample 13 without anti-corrosion coating treatment, its durability was improved by about 27.8%.

[0108] Meanwhile, the impact resistance of the lightweight corrosion-resistant material prepared by adding a certain amount of nano-carbon spheres to the composite epoxy resin was significantly improved. However, as the amount of nano-carbon spheres added gradually increased, the impact resistance of the lightweight corrosion-resistant material decreased to a certain extent. Therefore, the amount of nano-carbon spheres added in test sample 19 was relatively optimal.

Claims

1. A lightweight, corrosion-resistant material for automotive underbody protection panels, characterized in that, The lightweight corrosion-resistant material is made by combining an aramid-glass-carbon fiber composite layer with an LWRT board layer in an intralayer / interlayer hybrid manner, and the aramid-glass-carbon fiber composite layer and the LWRT board layer are bonded together with a composite epoxy resin; wherein, the aramid-glass-carbon fiber composite layer is woven from aramid fiber, glass fiber and carbon fiber in a warp-knitted four-axis structure. A method for preparing a lightweight, corrosion-resistant material for automotive underbody protection panels includes the following steps: S1. Preparation of aramid-glass-carbon fiber composite layer: Aramid fiber filament bundles, glass fiber filament bundles, and carbon fiber filament bundles were selected in a 1:1:2 ratio. An intralayer hybrid was woven using a warp-knitted four-axis structure. Composite epoxy resin was uniformly coated onto the upper surface of the intralayer hybrid at a volume ratio of 3:

2. A vacuum bag was then attached to the intralayer hybrid, and the hybrid was pressurized for 2 hours using the pressure difference generated by vacuuming, achieving a vacuum degree of 1×10⁻⁶. -2 ~1×10 -1 Pa, so that the composite epoxy resin can be uniformly penetrated from the upper surface to the lower surface of the hybrid in the layer until it is completely impregnated. After the penetration is complete, it is placed at room temperature for 24 hours to obtain an aramid-glass-carbon fiber composite layer with a thickness of 1~3mm. S2. Preparation of lightweight corrosion-resistant materials: n aramid-glass-carbon fiber composite layers with a thickness of 1~3mm and n-1 LWRT plates with a thickness of 1mm are stacked in an intra-layer / inter-layer hybrid manner, so that the top and bottom sides are aramid-glass-carbon fiber composite layers. During the stacking process, a composite epoxy resin with a thickness of 0.5~1mm is applied between each aramid-glass-carbon fiber composite layer and the LWRT plate. Then, a vacuum bag is attached to the intra-layer hybrid, and the intra-layer hybrid is pressurized for 2 hours by the pressure difference generated by vacuuming, with a vacuum degree of 1×10^-2~1×10^-1 Pa, so that each aramid-glass-carbon fiber composite layer and the LWRT plate are pressed together. After being placed at room temperature for 24 hours, a lightweight corrosion-resistant material is obtained. The carbon fiber needs to be etched, and carbamoyl hydrazine containing amino groups is attached to the etched carbon fiber in multiple stages. The method for etching the carbon fiber and attaching carbamoyl hydrazine containing amino groups to the etched carbon fiber in multiple stages is as follows: 1) Clean the carbon fiber with pure water, dry it, immerse the cleaned carbon fiber in a 30% nitric acid solution for 90 seconds, rinse the carbon fiber with pure water several times, and dry it to obtain the etched carbon fiber. 2) The etched carbon fiber was immersed in a 20% carbamoyl hydrazine aqueous solution. The carbon fiber was then removed, washed with pure water, and dried at 45°C for 30 seconds. It was then immersed in a 20% carbamoyl hydrazine aqueous solution for five times, with each immersion time being 12 minutes, to obtain carbon fiber with multi-stage adhesion treatment.

2. The lightweight corrosion-resistant material for automotive underbody protection plates as described in claim 1, characterized in that, In the warp-knitted four-axis structure of the aramid-glass-carbon fiber composite layer, the carbon fiber is warp-knitted at 45° and -45°, and the aramid fiber and glass fiber are warp-knitted at 0° and 90°. The matrix of the aramid-glass-carbon fiber composite layer is a composite epoxy resin.

3. The lightweight corrosion-resistant material for automotive underbody protection panels as described in claim 1, characterized in that, In the warp-knitted four-axis structure of the aramid-glass-carbon fiber composite layer, 10~20tex nylon low-elasticity yarn or polyester low-elasticity yarn is used as binding yarn.

4. The lightweight corrosion-resistant material for automotive underbody protection panels as described in claim 1, characterized in that, The preparation method of the composite epoxy resin is as follows: epoxy resin and curing agent are mixed at a mass ratio of 100:30, and nano carbon balls accounting for 2-6% of the total mass of epoxy resin and curing agent are added and mixed evenly.

5. A lightweight corrosion-resistant material for automotive underbody protection panels as described in claim 1, characterized in that, The linear density of the aramid fiber filament bundle, the linear density of the glass fiber filament bundle, and the linear density of the carbon fiber filament bundle are all 300~400tex, and 10~20tex nylon low-elastic yarn or polyester low-elastic yarn is used as binding yarn.

6. The method for preparing a lightweight corrosion-resistant material for automotive underbody protection plates as described in claim 1, characterized in that, The aramid-glass-carbon fiber composite layers on both sides of the lightweight corrosion-resistant material are coated with anti-corrosion paint.

Images