Manufacturing method of high-damping foaming material for automobile sheet metal

Abstract

The invention relates to the technical field of high-performance damping materials, and discloses a manufacturing method of a high-damping foaming material for automobile metal plates, and the foaming material comprises the following components: nitrile rubber, ethylene propylene diene monomer, epoxy resin, C9 petroleum resin, dicyandiamide, a plasticizer, an inorganic filler, sulfur, a foaming agent and a pigment. The manufacturing method comprises the following steps: mixing the rubber, the petroleum resin and other components at a certain temperature and rotating speed to form a matrix system, sequentially adding the epoxy resin, the filler, the dicyandiamide and the like, uniformly mixing, cooling, extruding a rubber layer in a rubber extruder, attaching aluminum foil glass fabric or release paper, and cutting and forming. By optimizing the material ratio and introducing a foaming system, high damping performance, excellent reinforcing effect and low sheet metal deformation degree are realized, and the material is suitable for damping, noise reduction and reinforcing requirements of automobile sheet metal, and has the characteristics of light weight, weather resistance and excellent processability.

Description

Technical Field

[0001] The present invention relates to the technical field of high-performance damping materials, and particularly to a manufacturing method of a high-damping foaming material for automotive sheet metal. Background Art

[0002] Automotive sheet metal materials are an important part of the vehicle structure. Their performance not only affects the overall rigidity and safety of the vehicle but also directly relates to the shock absorption, noise reduction effect inside the vehicle and the riding comfort. In recent years, with the development of the automotive industry, the performance requirements for sheet metal materials have been increasing day by day, especially the demands in aspects such as lightweight, durability, shock absorption, noise reduction and high strength are particularly prominent. However, the currently commonly used damping materials still have many limitations in performance and are difficult to meet the increasingly strict performance requirements.

[0003] In the prior art, damping sheet materials mostly use rubber as the main base material, but a single rubber material often has a balance problem between toughness and rigidity. Flexible rubber can provide certain damping performance, but its rigidity is insufficient, making it difficult to effectively improve the reinforcement ability of sheet metal, and it is prone to deformation or aging during long-term use, resulting in performance degradation. In order to enhance the strength and damping effect of the material, some technologies improve the rigidity and damping performance of the material by adding a high proportion of fillers or modified resins, but these methods usually lead to a significant increase in the density of the material, which is not conducive to the realization of automotive lightweight. In addition, a high proportion of fillers is likely to affect the processing fluidity of the material, resulting in uneven distribution problems during the forming process of the material, increasing the difficulty and cost of industrial production.

[0004] On the other hand, the performance of existing damping materials still has deficiencies under complex working conditions. For example, in a high-temperature environment, the internal stress of the material may cause significant deformation of the sheet metal, affecting its structural stability. In addition, in a long-term vibration and high-frequency noise environment, the damping performance of some materials is prone to attenuation and cannot continuously provide effective shock absorption and noise reduction effects. In addition, the single choice in the design of the adhesion layer of the current materials (such as only using fiberglass cloth or aluminum foil) is difficult to meet the comprehensive requirements for strength and damping in different application scenarios, which further limits its scope of use.

[0005] In summary, the damping materials in the prior art are difficult to achieve a comprehensive balance among damping performance, reinforcement ability, sheet metal deformation control, lightweight and processability. Especially in the automotive industry, there is an urgent need for a new type of material that can make breakthroughs in multiple performances to better meet the shock absorption and noise reduction requirements of automotive sheet metal under complex working conditions, and at the same time achieve the design goals of lightweight and high strength. Summary of the Invention

[0006] In view of the deficiencies of the prior art, the present invention provides a method for manufacturing a high-damping foaming material for automotive sheet metal, solving the technical problem that it is difficult to balance the shock absorption performance, reinforcement ability, sheet metal deformation control, and lightweight design of existing damping materials.

[0007] To achieve the above objectives, the present invention is realized through the following technical solutions: On the one hand, the present invention provides a high-damping foaming material for automotive sheet metal, which has efficient shock absorption and noise reduction performance, and at the same time has a reinforcement effect. The core lies in the unique composition and proportion optimization of the material. The main components include 30-50 parts of nitrile rubber, 40-50 parts of ethylene propylene diene monomer rubber, 50-150 parts of epoxy resin, 15-20 parts of C9 petroleum resin, 2-4.5 parts of dicyandiamide, 15-25 parts of plasticizer, 90-160 parts of inorganic filler, 0.8-1 part of sulfur, 1.5-3 parts of foaming agent, and 0.8-1 part of pigment.

[0008] The composition of the present invention through the compounding of nitrile rubber and ethylene propylene diene monomer rubber not only improves the flexibility and damping performance of the material, but also enhances the aging resistance and environmental adaptability. As the main reinforcing component in the matrix, epoxy resin acts synergistically with the rubber system to significantly enhance the strength and adhesion of the material. The introduction of C9 petroleum resin plays a role in toughening and improving the processing performance of the material, making the final product have good flexibility and ductility.

[0009] Dicyandiamide acts as a curing agent for epoxy resin in the system. After fully reacting with epoxy resin, it forms a stable network structure, thereby enhancing the mechanical properties and heat resistance of the material. The plasticizer not only ensures the flexibility of the material, but also improves the fluidity during processing. Inorganic fillers (such as calcium carbonate and talcum powder) greatly improve the density and compressive performance of the material through uniform dispersion with the rubber matrix, and optimize the cost.

[0010] The foaming agent (OBSH) generates tiny pores when heated, forming a microporous structure, significantly improving the shock absorption and energy absorption effects of the material. In addition, by adding an appropriate amount of sulfur and pigment to the composition, not only the crosslinking density of the rubber system is increased, but also the appearance and processing performance of the material are improved.

[0011] The material of the present invention has both high damping, good flexibility, and excellent reinforcement effect, and is suitable for various working conditions of automotive sheet metal, effectively reducing noise and vibration, while improving the strength of the sheet metal and vehicle safety.

[0012] Preferably, the acrylonitrile content of the nitrile rubber is 30% - 50%, and the Mooney viscosity is 50 - 60. The range of acrylonitrile content ensures a balance between oil resistance and flexibility of the nitrile rubber, which can not only meet the requirements of automotive sheet metal materials for chemical corrosion resistance but also ensure the flexibility and elasticity of the materials. The Mooney viscosity of 50 - 60 enables the nitrile rubber to have good processability and be more easily and uniformly mixed with other components during subsequent mixing and forming processes, ensuring the stability and consistency of the material system and thus improving the overall performance of the finished product.

[0013] Preferably, the Mooney viscosity of the ethylene propylene diene monomer (EPDM) rubber is 44 - 52, and the ENB content is 7.9% - 9.5%. This Mooney viscosity range ensures the processability of the EPDM rubber and its compatibility with other components, enabling it to be uniformly dispersed in the system during the mixing process. The selection of the ENB content in the range of 7.9% - 9.5% effectively improves the crosslinking efficiency of the material, enhances the heat resistance and anti-aging performance of the rubber matrix, while maintaining excellent flexibility and damping characteristics, meeting the usage requirements of automotive sheet metal materials under complex working conditions.

[0014] Preferably, the epoxy resin is bisphenol A epoxy resin, with an epoxy equivalent of 170 - 240 g / eq and a viscosity of 12000 - 15000 cps at 25°C. This epoxy resin has a relatively high epoxy equivalent range, which can form a dense crosslinked structure during the curing reaction, thus significantly improving the strength and bonding performance of the material. The viscosity of 12000 - 15000 cps at 25°C ensures good fluidity and dispersibility of the epoxy resin during the mixing process, while being fully combined with the rubber matrix, making the comprehensive performance of the material more balanced, especially achieving a good synergistic effect between high strength and high damping performance.

[0015] Preferably, the blowing agent is OBSH blowing agent, with a gas generation volume of 100 - 130 and a particle size of 8 - 12 μm. The OBSH blowing agent can produce a uniform and stable microporous structure in the material within this gas generation volume range, thus effectively improving the shock absorption and energy absorption effects of the material. The blowing agent with a particle size range of 8 - 12 μm has good dispersibility during the mixing process, which can ensure the uniform distribution of micropores and avoid the reduction of material strength caused by overly large pores, thus achieving an optimized balance between damping performance and mechanical properties and being suitable for the application requirements of automotive sheet metal shock absorption and noise reduction.

[0016] Preferably, the inorganic filler includes calcium carbonate and talcum powder with a particle size of 2 - 13 μm. The inorganic filler with a particle size range of 2 - 13 μm has good dispersibility in the material system, can effectively fill the rubber matrix, and improve the density and mechanical strength of the material. The addition of calcium carbonate can enhance the rigidity and dimensional stability of the material, while talcum powder helps to improve the heat resistance and processing performance of the material. The two work synergistically to optimize the flexibility and damping performance while ensuring the material strength, meeting the various working condition requirements in automotive sheet metal applications.

[0017] Preferably, the softening point of the C9 petroleum resin is 100 - 109 °C. Within this softening point range, the C9 petroleum resin can maintain appropriate fluidity during the mixing process, fully blend with the rubber matrix and other components, and provide moderate rigidity and adhesiveness after the material cools. Its function is to improve the toughening effect of the material, enhance the overall mechanical properties of the system, and improve the processing performance and use stability of the damping material, meeting the actual requirements of automotive sheet metal materials in different temperature environments.

[0018] Preferably, the particle size of the dicyandiamide is 5 - 10 μm. Within this particle size range, the dicyandiamide can be evenly dispersed in the material matrix during the mixing process and fully react with the epoxy resin to form a dense cross-linked network structure, thus significantly improving the mechanical properties and heat resistance of the material. At the same time, the moderate particle size helps to improve the curing efficiency, ensuring that the damping material has excellent stability and uniformity, and further enhancing its comprehensive performance in the field of automotive sheet metal shock absorption and noise reduction.

[0019] On the other hand, the present invention also provides a manufacturing method for a high-damping foamed material for automotive sheet metal, which ensures that the material has good damping performance and mechanical properties by optimizing process parameters. The specific steps include: 1) Mix ethylene propylene diene monomer rubber, nitrile rubber, and C9 petroleum resin at 75 - 85 °C and 45 - 55 revolutions per minute for 10 - 20 minutes to fully mix the rubber matrix and the toughening resin to form a preliminary mixture; 2) Add epoxy resin and continue mixing for 25 - 35 minutes to uniformly blend it with the matrix and gradually form a stable rubber-resin system; 3) Sequentially add sulfur, inorganic filler, plasticizer, pigment, and the remaining epoxy resin, and then mix for 15 - 25 minutes to ensure that each component is evenly dispersed and enhance the comprehensive performance of the material; 4) Add dicyandiamide and continue mixing for 5 - 15 minutes to evenly distribute the curing agent and react with the epoxy resin to further stabilize the internal network structure of the material; 5) Cool the mixed mixture to room temperature, preferably with a cooling time of 7 - 9 hours to ensure stable physical properties; then extrude it in a rubber extruder to form a rubber layer with a thickness of 1.8 - 2.2 mm; 6) Attach aluminum foil fiberglass cloth and release paper to the surface of the adhesive layer, and cut them into the required shape and specifications to prepare the high-damping foamed material.

[0020] By controlling the mixing time, temperature, and process steps, this method ensures the full fusion and uniform distribution of each component. At the same time, through the optimization of the cooling and forming processes, the damping performance and mechanical strength of the material are significantly improved, providing reliable technical support for the shock absorption, noise reduction, and reinforcement applications of automotive sheet metal.

[0021] The present invention provides a method for manufacturing a high-damping foamed material for automotive sheet metal. It has the following beneficial effects: 1. By introducing a foaming agent system, the present invention forms a uniform microporous structure inside the material, effectively absorbing and dispersing vibration energy, and significantly improving the damping performance of the material. The material exhibits excellent shock absorption and noise reduction capabilities and is suitable for the complex working conditions of automotive sheet metal.

[0022] 2. Through the synergistic effect of epoxy resin and inorganic fillers in the material, the present invention forms a high-strength crosslinked network and enhanced skeleton structure, greatly improving the rigidity and strength of the material, thereby effectively enhancing the reinforcement ability for sheet metal.

[0023] 3. Through the reasonable compounding of nitrile rubber and ethylene propylene diene monomer rubber, the present invention enables the material to simultaneously possess excellent flexibility and weather resistance, maintain stable mechanical properties during long-term use, and extend the service life of the material.

[0024] 4. By optimizing the material ratio and foaming structure design, the present invention effectively controls the internal stress distribution of the material, reduces the deformation amplitude of the sheet metal during high-temperature treatment, and ensures the structural stability.

[0025] 5. The introduction of the foaming system in the present invention reduces the material density while maintaining the balance of high damping and high strength, meets the design requirements of automotive lightweighting, and improves the fuel economy of the vehicle.

[0026] 6. The reasonable use of plasticizers and petroleum resins in the material formula of the present invention improves the processing fluidity and molding performance of the material, enables it to adapt to various manufacturing processes, and has good potential for industrial production.

[0027] 7. The material formula and process design of the present invention have flexibility, can be adjusted according to different application requirements, and are applicable to various working conditions in the shock absorption, noise reduction, structural reinforcement, and other related fields of automotive sheet metal. Specific embodiments

[0028] Next, in combination with the embodiments of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0029] Example 1: This embodiment provides a high-damping foaming material for automotive sheet metal, and its components and parts by weight are as follows: Nitrile rubber (acrylonitrile content 30 - 50%, Mooney viscosity 50 - 60, South China Rubber): 50 parts by weight; Ethylene propylene diene monomer rubber (Mooney viscosity 44 - 52, ENB content 7.9 - 9.5, LANXESS): 50 parts by weight; Bisphenol A epoxy resin (epoxy equivalent 170 - 240 g / equivalent, viscosity at 25°C 12000 - 15000 cps, South Asia Epoxy Resin Co., Ltd.): 100 parts by weight; C9 petroleum resin (softening point 100 - 109°C, ExxonMobil): 20 parts by weight; Dicyandiamide (particle size 5 - 10 μm): 3 parts by weight; Plasticizer (DOP): 20 parts by weight; Inorganic filler (calcium carbonate and talc powder, particle size 2 - 13 μm): 110 parts by weight; Sulfur (particle size 325 mesh): 1 part by weight; Blowing agent (OBSH, gas generation amount 100 - 130, particle size 8 - 12 μm): 1.5 parts by weight; Pigment (particle size 325 mesh): 1 part by weight.

[0030] The preparation method is as follows: 1. Put ethylene propylene diene monomer rubber, nitrile rubber and C9 petroleum resin into a Banbury mixer, and mix for 15 minutes at 80 ± 2°C and 50 ± 2 revolutions per minute to form a preliminary mixture; 2. Add epoxy resin and continue to mix for 30 minutes to form a rubber-resin system; 3. Sequentially add sulfur, the remaining epoxy resin, inorganic filler, plasticizer and pigment, and mix for 20 minutes; 4. Add dicyandiamide and mix for 10 minutes to form a uniformly mixed matrix; 5. After cooling the mixture for 8 hours, extrude a 2-mm-thick rubber layer on a rubber extruder; 6. Attach aluminum foil fiberglass cloth and release paper to the surface of the rubber layer, cut it into the required shape and specifications to obtain a damping reinforcement sheet.

[0031] Example 2: This embodiment provides a high-damping foaming material for automotive sheet metal, and its components are adjusted as follows on the basis of those in Embodiment 1: Nitrile rubber: 30 parts by weight; Styrene-butadiene rubber: 30 parts by weight; Ethylene propylene diene monomer (EPDM): 40 parts by weight; The other components and their parts by weight are the same as those in Embodiment 1.

[0032] The preparation steps are the same as those in Embodiment 1.

[0033] Embodiment 3: This embodiment provides a high-damping foaming material for automotive sheet metal, and its components are adjusted as follows on the basis of those in Embodiment 1: Nitrile rubber: 50 parts by weight; Ethylene propylene diene monomer (EPDM): 50 parts by weight; Bisphenol A epoxy resin: 150 parts by weight; Inorganic fillers (calcium carbonate and talcum powder): 160 parts by weight; Dicyandiamide: 4.5 parts by weight; Plasticizer (DOP): 15 parts by weight; The other components and their parts by weight are the same as those in Embodiment 1.

[0034] The preparation steps are the same as those in Embodiment 1.

[0035] Embodiment 4: This embodiment provides a high-damping foaming material for automotive sheet metal, and its components are adjusted as follows on the basis of those in Embodiment 1: Bisphenol A epoxy resin: 50 parts by weight; Inorganic fillers (calcium carbonate and talcum powder): 90 parts by weight; Dicyandiamide: 2 parts by weight; Plasticizer (DOP): 25 parts by weight; The other components and their parts by weight are the same as those in Embodiment 1.

[0036] The preparation steps are the same as those in Embodiment 1.

[0037] Embodiment 5: This embodiment provides a high-damping foaming material for automotive sheet metal, and its components are adjusted as follows on the basis of those in Embodiment 1: Bisphenol A epoxy resin: 150 parts by weight; Blowing agent (OBSH): 3 parts by weight; The other components and their parts by weight are the same as those in Embodiment 1.

[0038] The preparation steps are the same as those in Embodiment 1.

[0039] To verify the superiority of the embodiments of the present invention, a comparative test was conducted. The preparation methods and performance test results of the comparative examples are described below respectively.

[0040] Comparative Example 1: The difference from Example 1 is that instead of using the aluminum foil fiberglass cloth, fiberglass cloth with a weight of 280 grams was used as the attachment material for the final product. The other components and their ratios are the same as those in Example 1, and the damping reinforcement material was prepared according to the method of Example 1. A 2-mm-thick rubber layer was extruded on a rubber extruder, and the fiberglass cloth and the release paper were attached, and then cut into the required shape and size to obtain the damping reinforcement sheet.

[0041] Comparative Example 2: The difference from Example 1 is that instead of using the aluminum foil fiberglass cloth, aluminum foil with a thickness of 0.08 mm was used alone as the attachment material for the final product. The other components and their ratios are the same as those in Example 1, and the damping reinforcement material was prepared according to the method of Example 1. A 2-mm-thick rubber layer was extruded on a rubber extruder, and the aluminum foil and the release paper were attached, and then cut into the required shape and size to obtain the damping reinforcement sheet.

[0042] Comparative Example 3: The difference from Example 1 is that the rubber substrate was replaced with 100 parts by weight of butyl rubber 301, and the aluminum foil fiberglass cloth was not used. The other components and their ratios remained unchanged, and the damping reinforcement material was prepared according to the method of Example 1. A 2-mm-thick rubber layer was extruded on a rubber extruder, and the release paper was attached, and then cut into the required shape and size to obtain the damping reinforcement sheet.

[0043] Comparative Example 3: The difference from Example 1 is that the rubber substrate was replaced with 100 parts by weight of butyl rubber 301, and the aluminum foil fiberglass cloth was not used. The other components and their ratios remained unchanged, and the damping reinforcement material was prepared according to the method of Example 1. A 2-mm-thick rubber layer was extruded on a rubber extruder, and the release paper was attached, and then cut into the required shape and size to obtain the damping reinforcement sheet.

[0044] Performance Test: The following performance tests were conducted on the damping reinforcement sheets prepared in the examples and comparative examples, including tests of density, reinforcement multiple, sheet metal deformation degree, damping coefficient, and high-foaming ratio.

[0045] 1. Density Test The damping reinforcement sheet sample was cut into small pieces with dimensions of 50 mm × 50 mm × 2 mm, and an electronic densitometer was used to measure the density of the sample. The test environment was at room temperature of 25°C, and the result was expressed in g / cm 3 .

[0046] 2. Reinforcement Multiple Test Cut the sample into pieces of 300mm×25mm×2mm, fix them on a 5mm thick steel plate with a length of 300mm respectively, apply tensile force at both ends of the steel plate, measure the change in the bending displacement of the steel plate before and after the sample reinforcement, and calculate the reinforcement multiple. The test method is based on the standard of GB / T 9341-2008.

[0047] 3. Sheet metal deformation degree test Cut the damping reinforcement sheet into samples of 300mm×25mm×2mm, attach them to an aluminum plate with dimensions of 300mm×25mm×0.65mm, and perform baking treatment at 170°C for 20 minutes according to the standard of QC / T 851. After the treatment, let the sample stand at room temperature for 24 hours, and measure the horizontal distance between the highest point and the lowest point of the aluminum plate, with the unit of mm.

[0048] 4. Damping coefficient test Use a dynamic mechanical analyzer (DMA) to test the loss factor (tanδ) of the sample at 25°C, which is used as the characterization of the damping coefficient. The test frequency is 1Hz and the amplitude is 20μm.

[0049] 5. High expansion ratio test Heat the sample to foam at 170°C, measure the volume change before and after foaming after cooling, and calculate the expansion ratio (High expansion ratio = thickness after foaming / thickness before foaming).

[0050] The test results are shown in the following table: Analysis of test results: 1. Density The density of Examples 1-5 is controlled within the range of 1.09-1.27g / cm 3 , indicating that the foaming system effectively regulates the internal structure of the material. The blowing agent (OBSH) releases gas at high temperature to form a uniform microporous structure, which not only reduces the material density but also improves the shock absorption and energy absorption performance.

[0051] The microporous structure not only makes the material lighter in weight but also plays a buffering role in the vibration transmission process, improving the damping performance of the material. In Comparative Example 4, no blowing agent was added, resulting in an overly dense internal structure of the material. Although the density did not change significantly, the damping coefficient and expansion ratio decreased significantly (damping coefficient 0.16, expansion ratio 1.2), indicating that the foaming system is the key to improving the material performance.

[0052] 2. Reinforcement multiple The reinforcement multiple of Example 3 reaches 3.0, which is much higher than that of other examples. This benefits from the increase in the amount of epoxy resin (150 parts by weight). After synergistic action with inorganic fillers, it significantly improves the rigidity and strength of the material.

[0053] The reaction between epoxy resin and dicyandiamide forms a three-dimensional network structure with a high cross-linking density, improving the bending resistance of the material; the uniform dispersion of inorganic fillers (calcium carbonate and talcum powder) in the matrix forms a supporting framework structure, effectively resisting external forces. In Comparative Example 2, a single aluminum foil attachment material was used. Due to the lack of tight bonding between the aluminum foil and the material matrix, an effective overall constraint could not be formed, and the reinforcement multiple was only 1.2.

[0054] 3. Degree of sheet metal deformation In Example 4, the degree of sheet metal deformation is the lowest, only 0.3 mm, showing excellent anti-deformation ability. This is attributed to the optimization of the foaming system and material ratio, which not only reduces the density but also forms a stable internal and external support structure.

[0055] The uniform microporous structure generated by the foaming agent effectively buffers the internal stress during the heat treatment process, reducing the expansion and contraction of the sheet metal; at the same time, the compounding of rubber matrices (nitrile rubber and ethylene-propylene-diene monomer rubber) provides good flexibility and deformation recovery ability. In Comparative Example 3, butyl rubber was used as the main material. Due to its insufficient rigidity, the degree of sheet metal deformation was as high as 3.5 mm, unable to meet the requirements of practical applications.

[0056] 4. Damping coefficient The damping coefficient of Example 4 is the highest, 0.31, significantly superior to other examples. This is because a high cross-linking density epoxy-rubber composite structure is formed inside the material, and at the same time, the micropores generated by the foaming system improve the absorption efficiency of vibration energy.

[0057] The introduction of epoxy resin and C9 petroleum resin into the rubber matrix enhances the motion damping effect of molecular chains through chemical cross-linking and physical toughening; the micropores generated by the foaming system further absorb and disperse vibration energy. In Comparative Example 1, only a fiberglass cloth attachment material was used, which could not provide effective damping enhancement, resulting in a low damping coefficient of only 0.17.

[0058] 5. High foaming ratio The high foaming ratios of Example 4 and Example 5 are both 2.8, indicating that the foaming system plays an important role in optimizing the material properties. The uniform microporous structure not only improves the energy absorption ability but also effectively reduces the density of the material.

[0059] The foaming agent releases gas under high-temperature conditions and forms stable micropores after being restricted by the internal matrix of the material, which not only reduces the weight of the material but also improves the shock absorption and energy absorption performance. In Comparative Example 4, no foaming agent was added, resulting in a foaming ratio of only 1.2. The internal structure of the material is dense, and the shock absorption performance and the ability to control sheet metal deformation are significantly reduced.

[0060] From the above analysis, the following conclusions can be drawn: 1. The core role of the foaming system The blowing agent (OBSH) plays an important role in shock absorption, energy absorption, and reducing sheet metal deformation by generating a uniform microporous structure. The introduction of the foaming system significantly improves the damping coefficient and high foaming ratio, while effectively reducing the density, enabling the material to perform excellently under complex working conditions.

[0061] 2. Synergistic effect of epoxy resin and inorganic filler The high cross-linking density network structure formed by the curing of epoxy resin and dicyandiamide, together with the reinforcing framework composed of inorganic fillers, significantly improves the rigidity and reinforcement ability of the material. In Example 3, the content of epoxy resin and inorganic filler is relatively high, and the reinforcement multiple of the material reaches 3.0, showing a very strong reinforcement effect.

[0062] 3. Rational design of rubber matrix The compounding of nitrile rubber and ethylene propylene diene monomer rubber combines flexibility and aging resistance, providing good deformation control ability and environmental adaptability for the material. In Comparative Example 3, butyl rubber was used as the main material, and due to its insufficient rigidity and low damping performance, the degree of sheet metal deformation reached 3.5 mm, and the performance was significantly inferior to that of the example.

[0063] 4. Influence of the adhering material on the performance The aluminum foil fiberglass cloth adhering structure is adopted in the example, which not only enhances the comprehensive performance of the material, but also provides excellent adhesion and overall restraint effect. In Comparative Example 1 and Comparative Example 2, single fiberglass cloth or aluminum foil was used respectively, and due to the insufficient compatibility and binding force between materials, the balanced improvement of multiple performances could not be achieved.

[0064] In summary, through the introduction of the foaming system, the optimization of the rubber matrix, and the synergistic effect of epoxy resin and inorganic filler, the present invention shows excellent performance in key indicators such as density, reinforcement multiple, degree of sheet metal deformation, damping coefficient, and foaming ratio, and has significant technical advantages and application value compared with the comparative examples.

[0065] Although the embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A high-damping foaming material for automotive sheet metal, characterized in that, Comprising the following components in parts by weight: 30 - 50 parts of nitrile rubber, 40 - 50 parts of ethylene propylene diene monomer rubber, 50 - 150 parts of epoxy resin, 15 - 20 parts of C9 petroleum resin, 2 - 4.5 parts of dicyandiamide, 15 - 25 parts of plasticizer, 90 - 160 parts of inorganic filler, 0.8 - 1 part of sulfur, 1.5 - 3 parts of blowing agent, 0.8 - 1 part of pigment.

2. The high-damping foaming material for automotive sheet metal according to claim 1, wherein The acrylonitrile content of the nitrile rubber is 30% - 50%, and the Mooney viscosity is 50 - 60.

3. The high-damping foaming material for automotive sheet metal according to claim 1, wherein The Mooney viscosity of the ethylene propylene diene monomer rubber is 44 - 52, and the ENB content is 7.9% - 9.5%.

4. The high-damping foaming material for automobile sheet metal according to claim 1, wherein, The epoxy resin is bisphenol A type epoxy resin, with an epoxy equivalent of 170 - 240 g / equivalent and a viscosity of 12000 - 15000 cps at 25°C.

5. The high-damping foaming material for automobile sheet metal according to claim 1, wherein The blowing agent is OBSH blowing agent, with a gas generation amount of 100 - 130 and a particle size of 8 - 12 μm.

6. The high-damping foaming material for automotive sheet metal according to claim 1, characterized in that, The inorganic filler includes calcium carbonate and talcum powder with a particle size of 2 - 13 μm.

7. The high-damping foaming material for automobile sheet metal according to claim 1, wherein The softening point of the C9 petroleum resin is 100 - 109°C.

8. The high-damping foaming material for automotive sheet metal according to claim 1, wherein The particle size of the dicyandiamide is 5 - 10 μm.

9. A method for manufacturing a high-damping foaming material for automotive sheet metal, which is used to prepare the high-damping foaming material for automotive sheet metal according to any one of claims 1-8, characterized in that, Including the following steps: 1) Mix the ethylene propylene diene monomer rubber, nitrile rubber and C9 petroleum resin at 75 - 85°C and 45 - 55 revolutions per minute for 10 - 20 minutes; 2) Add the epoxy resin and mix for 25 - 35 minutes; 3) Sequentially add sulfur, inorganic filler, plasticizer, pigment and the remaining epoxy resin, and mix for 15 - 25 minutes; 4) Add dicyandiamide and mix for 5 - 15 minutes; 5) Cool the mixed mixture, and then extrude a rubber layer in a rubber extruder; 6) Attach aluminum foil fiberglass cloth and release paper to the surface of the rubber layer, and cut it into the required shape and specification.

10. The manufacturing method of the high-damping foaming material for automobile sheet metal according to claim 9, characterized in that, The cooling time after mixing is 7 - 9 hours, and the thickness of the extruded rubber layer is 1.8 - 2.2 mm.

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