Composite material as well as preparation method and application thereof

Abstract

The invention provides a composite material and a preparation method and application thereof, the composite material comprises an aramid fiber honeycomb material, at least part of the surface and / or pores of the aramid fiber honeycomb material are / is provided with a coating, and the coating is made of polyurea and nanometer aluminum oxide. According to the composite material, the coating containing the polyurea and the nanometer aluminum oxide is arranged on the aramid fiber honeycomb material, so that the material has the advantages of the aramid fiber honeycomb material and the polyurea, and the problem that an existing material is insufficient in impact resistance, corrosion resistance and the like is solved.

Description

Technical Field

[0001] The present application relates to the technical field of material preparation, and in particular to a composite material and a preparation method and application thereof. Background Art

[0002] With the increasing popularity of electric vehicles, the safety and lightweight protection of lithium-ion battery modules have become key design considerations. Battery modules are susceptible to impact damage in collisions, potentially leading to battery leakage or fire. Furthermore, lightweight protection is crucial to improving vehicle range, but this cannot come at the expense of structural strength. Therefore, designing a battery module protective layer that simultaneously meets these lightweight and crashworthy requirements has become a technical challenge in current electric vehicle design.

[0003] On the one hand, traditional aramid honeycomb materials have good performance in terms of lightness and high strength, but are prone to performance degradation in extreme environments, especially in impact and corrosion environments. In the existing technology, there are several typical methods for surface protection and enhancement of aramid honeycomb materials through coating:

[0004] (1) Phenolic resin coating: Phenolic resin has good adhesion and chemical corrosion resistance, but poor toughness. It is prone to brittle cracking under impact or repeated mechanical stress, causing the coating to break and lose its protective effect. In addition, phenolic resin has limited wear resistance and aging resistance. It is prone to aging and performance degradation when exposed to high temperature for a long time.

[0005] (2) Polyurethane coating: Polyurethane has good elasticity and initial wear resistance, but poor chemical corrosion resistance and thermal stability. It will degrade under high temperature conditions, resulting in a significant decrease in performance.

[0006] (3) Composite coating: Some technical solutions use multi-layer composite coatings, including a combination of metal coatings, ceramic coatings, and polymer coatings. Although composite coating technology can provide multiple protections, its process is complex and costly. In addition, the compatibility and adhesion between the layers of coating are difficult to ensure, and delamination may occur under multiple temperature cycles or mechanical stress. In addition, multi-layer composite coatings increase the weight of the material, which is not conducive to applications with strict lightweight requirements.

[0007] On the other hand, conventional polyurea coatings offer excellent wear and chemical resistance, but their combination with aramid honeycomb materials is limited, hindering the full utilization of their combined advantages. For example, related art discloses a composite material comprising, from the outside in, a polyurea protective layer, an alkali-free glass fiber epoxy prepreg, an aramid honeycomb absorbing plate, an alkali-free glass fiber epoxy prepreg, a 120-mesh copper screen, and an alkali-free glass fiber epoxy prepreg, each layer bonded together. This technology focuses on the material's absorbing properties rather than its impact resistance. Summary of the Invention

[0008] In view of this, one purpose of the present application is to provide a composite material, in which a coating containing polyurea and nano-alumina is arranged on an aramid honeycomb material, so that the material has the advantages of both aramid honeycomb material and polyurea, and solves the problem of insufficient impact resistance and corrosion resistance of existing materials.

[0009] Another object of the present application is to provide a method for preparing a composite material.

[0010] Yet another object of the present application relates to the use of the composite material.

[0011] To achieve the above objectives, the first aspect of the present application proposes a composite material, including an aramid honeycomb material, wherein at least part of the surface and / or pores of the aramid honeycomb material are provided with a coating, and the material of the coating includes polyurea and nano-alumina.

[0012] In some embodiments, the coating layer has a mass content of 0.1-99% in the composite material.

[0013] In some embodiments, the total mass content of the nano-aluminum oxide in the coating is 0.1-10%.

[0014] In some embodiments, the mass content of the nano-aluminum oxide in the coating layer gradually decreases from a side close to the aramid honeycomb material to a side far from the aramid honeycomb material.

[0015] In some embodiments, the coating includes a plurality of sub-coatings stacked in sequence, and the nano-alumina is evenly distributed in each sub-coating; in two adjacent sub-coatings, the mass content of the nano-alumina in the sub-coating close to the aramid honeycomb material is a%, and the mass content of the nano-alumina in the sub-coating away from the aramid honeycomb material is b%, a>b.

[0016] The composite material described in this application can at least bring the following beneficial effects:

[0017] Applying a coating containing polyurea and nano-alumina to an aramid honeycomb material combines the advantages of both aramid honeycomb and polyurea, resulting in excellent overall performance. This not only significantly improves the material's corrosion resistance, wear resistance, and impact resistance, but also effectively extends the product's service life and performance stability. Specifically, the lightweight and high-strength characteristics of aramid honeycomb and polyurea are utilized to meet the impact protection requirements of lithium-ion battery module housings for electric vehicles. Polyurea also outperforms conventional polymers in chemical corrosion resistance, wear resistance, impact resistance, and UV resistance (also known as aging resistance), performing particularly well in extreme environments such as humidity, acidity, alkalinity, or salt spray. Its excellent wear and impact resistance enables the product to maintain structural integrity and functional stability despite mechanical stress and wear. Furthermore, nano-alumina creates a heat transfer path, improving thermal conductivity (especially when the nano-alumina content in multiple sub-coatings decreases gradually or gradiently from the side closest to the aramid honeycomb to the side further away from the aramid honeycomb). Furthermore, the gradient distribution of nano-alumina within the coating significantly improves the material's mechanical properties. Finally, compared with existing traditional coating technologies, the composite material of the present application extends the service life of the material while reducing maintenance frequency and related costs.

[0018] A second aspect of the present application provides a method for preparing a composite material, comprising:

[0019] pre-treating the aramid honeycomb material to obtain a pre-treated aramid honeycomb material;

[0020] Mixing the polyurea and the nano-aluminum oxide to obtain a mixed coating;

[0021] The mixed coating is sprayed on the pretreated aramid honeycomb material, and then cured to obtain the composite material.

[0022] In some embodiments, the polyurea and the nano-alumina are mixed to obtain a mixed coating, comprising:

[0023] Dividing the polyurea into multiple equal portions;

[0024] Dividing the nano-alumina into the same number of parts as the polyurea according to mass;

[0025] Multiple portions of the nano-alumina with different masses are mixed with multiple portions of the polyurea to obtain multiple mixed coatings with different mass contents of the nano-alumina.

[0026] In some embodiments, spraying the mixed coating on the pretreated aramid honeycomb material and then curing the mixed coating comprises:

[0027] The multi-molecule mixed coating is sprayed on the pretreated aramid honeycomb material in order of decreasing mass content of the nano-alumina, and the curing is performed after each spraying.

[0028] In some embodiments, the spraying method is a two-fluid atomization spraying process.

[0029] In some embodiments, in the two-fluid atomization spraying process, the fluid includes at least one of air, argon, and nitrogen.

[0030] In some embodiments, in the two-fluid atomization spraying process, the diameter of the mixed coating droplets is controlled to be 1-10 μm.

[0031] In some embodiments, the aramid honeycomb material is pretreated, comprising:

[0032] The aramid honeycomb material is subjected to a first washing, polishing, a second washing, and a surface activation treatment.

[0033] In some embodiments, the detergent used in the first washing comprises ethanol and water.

[0034] In some embodiments, the polishing includes at least one of mechanical polishing and sandpaper polishing;

[0035] In some embodiments, the detergent used in the second wash comprises ethanol.

[0036] In some embodiments, the surface activation treatment method includes low-temperature plasma surface activation treatment; preferably, during the low-temperature plasma surface activation treatment, the spray gun processing speed is 100-150 mm / s, the distance between the muzzle and the polished aramid honeycomb material is 15-20 mm, the nozzle adopts linear reciprocating motion, the processing time is 10-20 s, and the processing temperature is 50-80 ° C.

[0037] In some embodiments, the method for preparing the composite material further includes a step of preparing the polyurea before mixing the polyurea and the nano-alumina; the preparation of the polyurea includes: mixing polyisocyanate and polyamine at a functional group molar ratio of 1: (0.8-1.2) and stirring at -20°C to -200°C.

[0038] The method for preparing the composite material described in this application, in addition to the beneficial effects of the composite material described in this application, can also bring at least the following beneficial effects:

[0039] 1. Introducing nano-alumina fillers into the polyurea coating and proposing a design concept of gradient spraying (spraying multi-molecule mixed coatings in descending order according to the mass of nano-alumina on the pre-treated aramid honeycomb material) can more effectively improve the thermal conductivity of the material.

[0040] 2. A dual-fluid atomization spray process precisely controls the polyurea coating curing process, and a multi-layer coating scheme achieves uniformity and density, ensuring the coating's mechanical properties and adhesion. This process is more reliable and efficient than existing immersion coating technology. The optimized coating process reduces coating defects, improves the material's overall performance, and ensures stability under long-term or high-stress conditions.

[0041] 3. The preparation method of the composite material not only enhances the curing quality of the polyurea coating, but also significantly improves the heat dissipation capacity of the aramid honeycomb structure, thereby better meeting the thermal management requirements of the power battery module under complex working conditions and improving the safety and stability of the battery system.

[0042] The third aspect of the present application relates to the use of the composite material described in the present application or the composite material prepared by the method for preparing the composite material described in the present application in lightweight structural devices.

[0043] In some embodiments, the lightweight structural device includes one of military and protective equipment, construction and infrastructure, transportation equipment, electronic equipment, and other equipment requiring collision protection.

[0044] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the following description of the embodiments in conjunction with the accompanying drawings.

[0046] in:

[0047] Figure 1 The flowchart of the method for preparing a composite material is shown as an exemplary embodiment of the present application. DETAILED DESCRIPTION

[0048] The embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to be used to explain the present application, but should not be understood as limiting the present application.

[0049] Throughout this application, the disclosure of numerical ranges includes disclosure of all values ​​within the entire range and further subdivided ranges, including the endpoints and subranges given within those ranges.

[0050] In this application, the raw materials, equipment, etc. involved, unless otherwise specified, are all raw materials and equipment that can be obtained through commercial channels or known methods; the methods involved, unless otherwise specified, are all conventional methods.

[0051] The term "and / or," when used in conjunction with a list of two or more items, means that any of the listed items can be used alone or in combination with any one or more of the listed items. For example, the expression "A and / or B" is intended to mean A or B or A and B, that is, only A, only B, or a combination of A and B.

[0052] The inventors discovered that while traditional aramid honeycomb materials offer excellent lightness and high strength, they are susceptible to performance degradation in extreme environments, particularly impact and corrosion. Conventional polyurea coatings offer excellent wear and chemical resistance, but combining the two fails to fully exploit their combined strengths. Therefore, this application aims to develop a composite material with enhanced impact resistance and a method for its preparation. By coating the aramid honeycomb structure with a coating containing polyurea and nano-alumina, the material's overall mechanical properties are further enhanced, meeting the stringent material requirements of battery cells. Specifically, the application aims to provide a comprehensive solution with superior impact resistance for applications in extreme environments and under high dynamic loads.

[0053] <Composite Materials>

[0054] The composite material of the embodiment of the present application includes an aramid honeycomb material, wherein a coating is provided on at least a portion of the surface and / or pores of the aramid honeycomb material, and the material of the coating includes polyurea and nano-aluminum oxide.

[0055] It can be understood that, in the composite material of the embodiment of the present application, the coating is distributed on at least a portion of the surface of the aramid honeycomb material, and / or distributed in at least a portion of the pores of the aramid honeycomb material.

[0056] In some embodiments, the coating comprises 0.1-99% by weight of the composite material, including but not limited to 5%, 10%, 20%, 25%, 30%, 40%, 50%, 60%, 70%, 80%, or 90%. Within this range, the coating thickness is sufficient to provide effective structural protection and functional enhancement while avoiding excessive weight and material waste. If the coating content is less than 0.1%, a continuous "shell" layer cannot be formed, resulting in limited improvement in the impact resistance or compression performance of the honeycomb. If the coating content is greater than 99%, the overall weight of the material is significantly increased.

[0057] In some embodiments, the total mass content of the nano-aluminum oxide in the coating is 0.1-10%, including but not limited to 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8% or 9%.

[0058] As an optional example, the composite material comprises the aramid honeycomb material and the coating, wherein the coating is distributed on at least a portion of the surface and / or pores of the aramid honeycomb material, and the coating comprises polyurea and nano-alumina. In this case, the composite material is a composite material of the aramid honeycomb material, polyurea, and nano-alumina.

[0059] In some embodiments, the mass content of the nano-aluminum oxide in the coating gradually decreases from the side close to the aramid honeycomb material to the side away from the aramid honeycomb material, for example, linearly or gradiently.

[0060] As an optional example, the coating includes a plurality of sub-coatings stacked in sequence, and the nano-alumina is evenly distributed in each sub-coating; in two adjacent sub-coatings, the mass content of the nano-alumina in the sub-coating close to the aramid honeycomb material is a%, and the mass content of the nano-alumina in the sub-coating away from the aramid honeycomb material is b%, a>b.

[0061] Alternatively, the mass content of the nano-alumina in the composite material in the multiple sub-coatings may decrease gradually. That is, the difference in mass content of the nano-alumina in the composite material between two adjacent sub-coatings is equal, for example, 0.5%, 1%, 1.5%, or 2%. This arrangement helps improve the thermal conductivity and mechanical properties of the material.

[0062] In some embodiments, the number of sub-coating layers is greater than 2, such as 3, 4, 5, or 6.

[0063] In some embodiments, when the coating comprises a plurality of sub-coatings, the thickness of each sub-coating may be the same or different, preferably the same.

[0064] The composite material of the embodiment of the present application can at least bring the following beneficial effects:

[0065] Applying a coating containing polyurea and nano-alumina to an aramid honeycomb material combines the advantages of both aramid honeycomb and polyurea, resulting in excellent overall performance. This not only significantly improves the material's corrosion resistance, wear resistance, and impact resistance, but also effectively extends the product's service life and performance stability. Specifically, the lightweight and high-strength characteristics of aramid honeycomb and polyurea are utilized to meet the impact protection requirements of lithium-ion battery module housings for electric vehicles. Polyurea also outperforms conventional polymers in chemical corrosion resistance, wear resistance, impact resistance, and UV resistance (also known as aging resistance), performing particularly well in extremely harsh environments such as humidity, acidity, alkalinity, or salt spray. Its excellent wear and impact resistance enables the product to maintain structural integrity and functional stability despite mechanical stress and wear. Furthermore, nano-alumina creates a heat transfer path, improving thermal conductivity (especially when the nano-alumina content in multiple sub-coatings decreases gradually or gradiently from the side closest to the aramid honeycomb to the side further away from the aramid honeycomb). Furthermore, the gradient distribution of nano-alumina within the coating improves the material's mechanical properties. Finally, compared with existing traditional coating technologies, the composite material of the present application extends the service life of the material while reducing maintenance frequency and related costs.

[0066] <Method for preparing composite material>

[0067] The method for preparing the composite material of the embodiment of the present application can be used to prepare the composite material of the embodiment of the present application.

[0068] Figure 1 The flowchart of the method for preparing a composite material is shown as an exemplary embodiment of the present application.

[0069] like Figure 1 As shown, the preparation method of the composite material comprises the following steps:

[0070] S101 , pre-treating the aramid honeycomb material to obtain a pre-treated aramid honeycomb material.

[0071] In some embodiments, the aramid honeycomb material is pretreated, including: performing a first washing, polishing, a second washing, and a surface activation treatment on the aramid honeycomb material.

[0072] In the embodiments of the present application, the function of the first washing is to remove oil and impurities on the surface of the aramid honeycomb material, the function of the polishing is to increase the roughness of the surface of the aramid honeycomb material, and the function of the second washing is to remove possible pollutants and polishing residues on the honeycomb surface, such as grease, dust and other impurities. The purpose of the surface activation treatment is to change the properties of the surface of the honeycomb material by physical or chemical methods to enhance its bonding ability with subsequent coatings.

[0073] In some embodiments, the detergent used in the first washing includes but is not limited to at least one of ethanol and water.

[0074] In the embodiment of the present application, the water in the detergent used in the first washing can be deionized water, distilled water, etc. When water and ethanol are used, the mass ratio of water to ethanol is not limited and can be any mass ratio, such as 1:1, 1:2 or 2:1.

[0075] In some embodiments, the polishing includes at least one of mechanical polishing and sandpaper polishing.

[0076] In the embodiment of the present application, the sandpaper polishing force should be light, the purpose of which is to remove tiny impurities, oxide layers or residues that may exist on the surface, but not to damage the honeycomb.

[0077] In some embodiments, the detergent used in the second washing includes but is not limited to at least one of ethanol, water, isopropanol, etc.

[0078] In some embodiments, the surface activation treatment method includes low-temperature plasma surface activation treatment; preferably, during the low-temperature plasma surface activation treatment, the spray gun processing speed is 100-150 mm / s, the distance between the gun muzzle and the workpiece (that is, the polished aramid honeycomb material) is 15-20 mm, the nozzle adopts linear reciprocating motion, the processing time is 10-20 s, and the processing temperature is 50-80 ° C.

[0079] Exemplarily, the spray gun processing speed includes but is not limited to 110 mm / s, 120 mm / s or 130 mm / s, etc.

[0080] For example, the distance between the muzzle and the workpiece (ie, the polished aramid honeycomb material) includes but is not limited to 16 mm, 17 mm, or 18 mm.

[0081] Illustratively, during the low-temperature plasma surface activation treatment, the treatment time includes but is not limited to 12s, 15s or 18s.

[0082] Illustratively, during the low-temperature plasma surface activation treatment, the treatment temperature includes but is not limited to 60° C. or 75° C.

[0083] Illustratively, during the low-temperature plasma surface activation treatment, the plasma includes but is not limited to at least one of nitrogen, oxygen, helium, etc.

[0084] In some embodiments, the aramid honeycomb material is an aramid honeycomb material with a thickness not exceeding 10 mm.

[0085] S102, mixing the polyurea and the nano-aluminum oxide to obtain a mixed coating.

[0086] In some embodiments, the method for preparing the composite material further comprises a step of preparing the polyurea before mixing the polyurea and the nano-alumina.

[0087] As an optional example, the preparation of the polyurea includes: mixing polyisocyanate and polyamine at a functional group molar ratio of 1: (0.8-1.2) and stirring at -20-200° C. (eg, 80° C., etc.).

[0088] In the embodiments of the present application, polyisocyanate refers to a dibasic or higher-valent isocyanate (an isocyanate containing two or more isocyanate groups), and polyamine refers to a dibasic or higher-valent amine (an amine containing two or more amino groups). In addition, the functional group molar ratio of polyisocyanate to polyamine refers to the molar ratio of isocyanate groups in the polyisocyanate to amino groups in the polyamine.

[0089] Exemplarily, the polyisocyanate includes, but is not limited to, at least one of toluene diisocyanate, diphenylmethane diisocyanate, naphthalene diisocyanate, and a trimer of hexamethylene diisocyanate.

[0090] For example, the polyamine includes, but is not limited to, at least one of ethylenediamine, hexamethylenediamine, triethylamine, 4,4'-diaminodiphenylmethane, 4,4'-diaminostilbene, and 2,4-diaminodiphenylmethane.

[0091] Illustratively, the functional group molar ratio of the polyisocyanate to the polyamine includes, but is not limited to, 1:0.9, 1:1, or 1:1.1, and is preferably 1:1.

[0092] In the embodiments of the present application, the polyisocyanate and the polyamine are mixed and stirred at -20°C to -200°C (eg, -10°C, 0°C, 40°C, 80°C, or 120°C), which can increase the fluidity of the polymer.

[0093] In some embodiments, the method of mixing the polyurea and the nano-alumina includes but is not limited to ultrasonic dispersion, stirring, and the like.

[0094] In some embodiments, when the composite coating comprises a plurality of sub-coatings, mixing the polyurea and the nano-alumina to obtain a mixed coating comprises the following steps:

[0095] (1) dividing the polyurea into multiple equal parts;

[0096] (2) dividing the nano-alumina into the same number of parts as the polyurea according to mass;

[0097] (3) Mixing multiple portions of the nano-alumina with different masses with multiple portions of the polyurea to obtain multiple mixed coatings with different mass contents of the nano-alumina.

[0098] It should be noted that, in other embodiments, it is also possible to directly take polyurea with a mass equivalent to that of the above-mentioned polyurea after being evenly divided into multiple portions, and then add the same nano-alumina with the same mass content as in the above step (3) to form a multi-molecule mixed coating with different mass contents of nano-alumina.

[0099] S103 , spraying the mixed coating obtained in step S102 on the pretreated aramid honeycomb material obtained in step S101 , followed by curing to obtain the composite material.

[0100] In some embodiments, the spraying method is a two-fluid atomization spraying process.

[0101] In some embodiments, in the two-fluid atomization spraying process, the fluid includes but is not limited to at least one of air, argon, nitrogen, etc., and air can be selected.

[0102] In some embodiments, in the two-fluid atomization spraying process, the diameter of the mixture droplets is controlled to be 1-10 μm.

[0103] For example, in the two-fluid atomization spraying process, the diameter of the mixture droplets can be controlled to include but is not limited to 3 μm, 5 μm, 7 μm or 10 μm.

[0104] For example, in the two-fluid atomization spraying process, the pressure is 1-6 bar, including but not limited to 2 bar, 3 bar, 4 bar or 5 bar, etc. The higher the pressure, the better the atomization effect, but too high a pressure will break the honeycomb paper.

[0105] Exemplarily, in the two-fluid atomization spraying process, the temperature is 20-40°C, such as 30°C.

[0106] Exemplarily, in the two-fluid atomization spraying process, the movement speed of the spray gun is 30 cm / s to 60 cm / s, including but not limited to 40 cm / s or 50 cm / s.

[0107] In the embodiments of the present application, the specific operation method and other possible operation process parameters of the two-fluid atomization spray process are well known in the art and will not be described in detail here.

[0108] In some embodiments, the curing temperature is 0-100°C, including but not limited to 10°C, 35°C, 40°C, 60°C, or 80°C.

[0109] In some embodiments, when the coating in the composite material includes a plurality of sub-coatings, spraying the mixed coating on the pretreated aramid honeycomb material and then curing the mixed coating comprises:

[0110] The multi-molecule mixed coating is sprayed on the pretreated aramid honeycomb material in order of decreasing mass content of the nano-alumina, and the curing is performed after each spraying.

[0111] In the embodiment of the present application, the order of step S101 and step S102 can be adjusted as needed.

[0112] The method for preparing the composite material of the embodiment of the present application, in addition to the beneficial effects of the composite material of the embodiment of the present application, can also bring at least the following beneficial effects:

[0113] 1. Introducing nano-alumina fillers into the polyurea coating and proposing a design concept of gradient spraying (spraying multi-molecule mixed coatings in descending order according to the mass of nano-alumina on the pre-treated aramid honeycomb material) can more effectively improve the thermal conductivity of the material.

[0114] 2. A dual-fluid atomization spray process precisely controls the polyurea coating curing process, and a multi-layer coating scheme achieves uniformity and density, ensuring the coating's mechanical properties and adhesion. This process is more reliable and efficient than existing immersion coating technology. The optimized coating process reduces coating defects, improves the material's overall performance, and ensures stability under long-term or high-stress conditions.

[0115] 3. The preparation method of the composite material not only enhances the curing quality of the polyurea coating, but also significantly improves the heat dissipation capacity of the aramid honeycomb structure, thereby better meeting the thermal management requirements of the power battery module under complex working conditions and improving the safety and stability of the battery system.

[0116] <Application of composite materials>

[0117] The composite materials of the embodiments of the present application or the composite materials prepared by the methods for preparing the composite materials of the embodiments of the present application can be widely used in lightweight structural devices, etc.

[0118] In some embodiments, the lightweight structural device includes, but is not limited to, one of military and protective equipment, construction and infrastructure, transportation equipment, electronic equipment, and other equipment requiring collision protection.

[0119] Exemplary applications in military and protective equipment include, but are not limited to, use in the manufacture of bulletproof vests, blast-proof walls, vehicle armor, etc., providing excellent protection capabilities and impact resistance.

[0120] Exemplary applications in construction and infrastructure include, but are not limited to, applications in protective layers for structures such as bridges, tunnels, and oil platforms to enhance the corrosion resistance and durability of the structures.

[0121] Exemplarily, applications in transportation equipment include, but are not limited to, structural components for vehicles, ships, aircraft, etc., to improve their impact resistance and long-term weather resistance.

[0122] Exemplary applications in electronic devices include, but are not limited to, applications in electronic device housings to provide better protection and durability, extend the service life of the device, etc.

[0123] Certain features of the present technology are further illustrated in the following non-limiting examples.

[0124] Example 1

[0125] The method for preparing the composite material of this embodiment comprises the following steps:

[0126] (1) An aramid honeycomb material with a thickness of 8 mm was selected. Its surface was first cleaned with a mixture of anhydrous ethanol and deionized water (the mass ratio of anhydrous ethanol to deionized water was 1:1) to remove surface oil and impurities. Next, its surface was mechanically polished using sandpaper to gently polish it to roughen the surface, thereby obtaining a polished aramid honeycomb material.

[0127] (2) Cleaning the surface of the polished aramid honeycomb material obtained in step (1) using anhydrous ethanol solvent, and performing surface activation treatment using low-temperature plasma to obtain a pretreated aramid honeycomb material.

[0128] Among them, during the surface activation treatment process of low-temperature plasma, the spray gun processing speed is 125mm / s, the distance between the gun muzzle and the polished aramid honeycomb material is 18mm, the nozzle adopts linear reciprocating motion, the processing time is 15s, the processing temperature is 80℃, and the plasma is nitrogen.

[0129] (3) Component A and component B, which form polyurea, were mixed at a functional group molar ratio of 1:1 and stirred at 80°C for 0.5 h to obtain polyurea. Nanoalumina (median particle size of 50 nm) was added to the polyurea, stirred uniformly, and then ultrasonically dispersed for 10 min to obtain a mixed coating.

[0130] Component A is polyisocyanate 4,4'-diphenylmethane diisocyanate, and component B is polyamine 4,4'-diaminodiphenylmethane; and the added amount of nano-alumina is 2% of the total mass of polyurea and nano-alumina.

[0131] (4) The mixed coating obtained in step (3) is placed in a sprayer and evenly sprayed onto the surface of the pretreated aramid honeycomb material obtained in step (2) using a two-fluid atomization spraying process. After spraying, the mixture is cured for 24 hours to obtain a composite material.

[0132] Among them, in the two-fluid atomization spraying process, the fluid is air, the diameter of the mixed coating is controlled at 5μm, the pressure is 3bar, the temperature is 30℃, and the spray gun movement speed is 45cm / s.

[0133] In this embodiment, the total mass of polyurea and nano-alumina is m, the total mass of polyurea, nano-alumina and aramid honeycomb material is n, (m / n)*100%=20% (that is, in the final composite material product, the mass content of the coating composed of polyurea and nano-alumina is 20%).

[0134] The composite material prepared in this embodiment was tested for mechanical properties such as compressive strength, L-direction shear strength, and W-direction shear strength. The compression test was conducted in accordance with GB / T 1453, and the shear test was conducted in accordance with GB / T 1455. Three batches of test pieces were tested at room temperature (23°C ± 3°C), with each batch containing six test pieces. The mechanical properties test results of the composite material prepared in Example 1 were as follows: compressive strength of 2.95 MPa, L-direction shear strength of 1.92 MPa, and W-direction shear strength of 1.08 MPa.

[0135] Example 2

[0136] The method for preparing the composite material of this embodiment comprises the following steps:

[0137] (1) An aramid honeycomb material with a thickness of 8 mm was selected. Its surface was first cleaned with a mixture of anhydrous ethanol and deionized water (the mass ratio of anhydrous ethanol to deionized water was 1:1) to remove surface oil and impurities. Next, its surface was mechanically polished using sandpaper to gently polish it to roughen the surface, thereby obtaining a polished aramid honeycomb material.

[0138] (2) Cleaning the surface of the polished aramid honeycomb material obtained in step (1) using anhydrous ethanol solvent, and performing surface activation treatment using low-temperature plasma to obtain a pretreated aramid honeycomb material.

[0139] Among them, during the surface activation treatment process of low-temperature plasma, the spray gun processing speed is 125mm / s, the distance between the gun muzzle and the polished aramid honeycomb material is 18mm, the nozzle adopts linear reciprocating motion, the processing time is 15s, the processing temperature is 80℃, and the plasma is nitrogen.

[0140] (3) Component A and component B, which form a polyurea, were mixed at a functional group molar ratio of 1:1 and stirred at 80°C for 0.5 h to obtain a polyurea. The polyurea was divided into three equal parts by mass and labeled as the first polyurea, the second polyurea, and the third polyurea.

[0141] Wherein, component A is polyisocyanate 4,4'-diphenylmethane diisocyanate, and component B is polyamine 4,4'-diaminodiphenylmethane.

[0142] (4) Adding nano-alumina (median particle size of 50 nm) to the first polyurea obtained in step (3), stirring evenly and then performing ultrasonic dispersion treatment for 10 minutes to obtain a first sub-mixed coating.

[0143] The added amount of nano-alumina is 3% of the total mass of the first polyurea and the nano-alumina.

[0144] (5) Adding nano-alumina (median particle size of 50 nm) to the second polyurea obtained in step (3), stirring evenly and then performing ultrasonic dispersion treatment for 10 minutes to obtain a second sub-mixed coating.

[0145] The added amount of nano-alumina is 2% of the total mass of the second polyurea and the nano-alumina.

[0146] (6) Add nano-alumina (median particle size of 50 nm) to the third polyurea obtained in step (3), stir evenly, and then perform ultrasonic dispersion treatment for 10 minutes to obtain a third sub-mixed coating.

[0147] The added amount of nano-alumina is 1% of the total mass of the third polyurea and the nano-alumina.

[0148] (7) The first sub-mixed coating obtained in step (4) is placed in a sprayer and uniformly sprayed onto the surface of the pretreated aramid honeycomb material obtained in step (2) using a two-fluid atomization spraying process. After spraying, the mixture is cured for 8 hours to obtain an aramid honeycomb material containing the first coating.

[0149] Among them, in the two-fluid atomization spraying process, the fluid is air, the diameter of the first sub-mixed paint is controlled at 5μm, the pressure is 3bar, the temperature is 30℃, and the spray gun movement speed is 45cm / s.

[0150] (8) The second sub-mixed coating obtained in step (5) is placed in a sprayer and uniformly sprayed onto the surface of the first coating layer of the aramid honeycomb material containing the first coating layer obtained in step (7) using a two-fluid atomization spraying process. After spraying, the mixture is cured for 8 hours to obtain an aramid honeycomb material containing the second coating layer.

[0151] Among them, in the two-fluid atomization spraying process, the fluid is air, the diameter of the second sub-mixed paint is controlled at 5μm, the pressure is 3bar, the temperature is 30℃, and the spray gun movement speed is 45cm / s.

[0152] (9) The third sub-mixed coating obtained in step (6) is placed in a sprayer and uniformly sprayed onto the surface of the second coating layer of the aramid honeycomb material containing the second coating layer obtained in step (8) using a two-fluid atomization spraying process. After spraying, the mixture is cured for 8 hours to obtain the aramid honeycomb material containing the third coating layer, i.e., the composite material of this embodiment.

[0153] Among them, in the two-fluid atomization spraying process, the fluid is air, the diameter of the third sub-mixed paint is controlled at 5μm, the pressure is 3bar, the temperature is 30℃, and the spray gun movement speed is 45cm / s.

[0154] In this embodiment, the total mass of the polyurea, the nano-alumina in step (4), the nano-alumina in step (5) and the nano-alumina in step (6) is m, and the total mass of the polyurea, the nano-alumina in step (4), the nano-alumina in step (5), the nano-alumina in step (6) and the aramid honeycomb material is n, (m / n)*100%=20% (that is, in the final composite material product, the mass content of the coating composed of polyurea and nano-alumina is 20%).

[0155] The composite material prepared in this embodiment was tested for mechanical properties such as compressive strength, L-direction shear strength, and W-direction shear strength. The compression test was conducted in accordance with GB / T 1453, and the shear test was conducted in accordance with GB / T 1455. Three batches of test pieces were tested at room temperature (23°C ± 3°C), with each batch containing six test pieces. The mechanical properties test results of the composite material prepared in Example 2 were: compressive strength of 3.63 MPa, L-direction shear strength of 2.31 MPa, and W-direction shear strength of 1.29 MPa.

[0156] Example 3 (compared with Example 2, the spraying process parameters are set differently)

[0157] This embodiment is basically the same as embodiment 2, except that:

[0158] In step (7), the diameter of the first sub-mixed coating in the two-fluid atomization spraying process is controlled to be 10 μm;

[0159] In step (8), the diameter of the second sub-mixed coating in the two-fluid atomization spraying process is controlled to be 10 μm;

[0160] In step (9), the diameter of the third sub-mixed coating in the two-fluid atomization spraying process is controlled to be 10 μm.

[0161] The composite material prepared in this embodiment was tested for mechanical properties such as compressive strength, L-direction shear strength, and W-direction shear strength. The compression test was conducted in accordance with GB / T 1453, and the shear test was conducted in accordance with GB / T 1455. Three batches of test pieces were tested at room temperature (23°C ± 3°C), with each batch containing six test pieces. The mechanical properties test results of the composite material prepared in Example 3 were: compressive strength of 3.36 MPa, L-direction shear strength of 2.21 MPa, and W-direction shear strength of 1.10 MPa.

[0162] Example 4 (Compared with Example 2, the nano-alumina gradient setting is different)

[0163] This embodiment is basically the same as embodiment 2, except that:

[0164] In step (4), the amount of nano-alumina added is 2.5% of the total mass of the first polyurea and the nano-alumina.

[0165] In step (5), the amount of nano-alumina added is 2% of the total mass of the second polyurea and the nano-alumina.

[0166] In step (6), the amount of nano-alumina added is 1.5% of the total mass of the third polyurea and the nano-alumina.

[0167] The composite material prepared in this embodiment was tested for mechanical properties such as compressive strength, L-direction shear strength, and W-direction shear strength. The compression test was conducted in accordance with GB / T 1453, and the shear test was conducted in accordance with GB / T 1455. Three batches of test pieces were tested at room temperature (23°C ± 3°C), with each batch containing six test pieces. The mechanical properties test results of the composite material prepared in Example 4 were: compressive strength of 3.49 MPa, L-direction shear strength of 2.25 MPa, and W-direction shear strength of 1.21 MPa.

[0168] Example 5 (Compared with Example 1, the specifications of the aramid honeycomb material are different)

[0169] The method for preparing the composite material of this embodiment comprises the following steps:

[0170] (1) A 10 mm thick aramid honeycomb material was selected and its surface was first cleaned with a mixture of anhydrous ethanol and deionized water (the mass ratio of anhydrous ethanol to deionized water was 1:1) to remove surface oil and impurities. Next, the surface was mechanically polished using sandpaper to roughen the surface, obtaining a polished aramid honeycomb material.

[0171] (2) Cleaning the surface of the polished aramid honeycomb material obtained in step (1) using anhydrous ethanol solvent, and performing surface activation treatment using low-temperature plasma to obtain a pretreated aramid honeycomb material.

[0172] Among them, during the surface activation treatment process of low-temperature plasma, the spray gun processing speed is 125mm / s, the distance between the gun muzzle and the polished aramid honeycomb material is 18mm, the nozzle adopts linear reciprocating motion, the processing time is 15s, the processing temperature is 80℃, and the plasma is nitrogen.

[0173] (3) Component A and component B, which form polyurea, were mixed at a functional group molar ratio of 1:1 and stirred at 80°C for 0.5 h to obtain polyurea. Nanoalumina (median particle size of 50 nm) was added to the polyurea, stirred uniformly, and then ultrasonically dispersed for 10 min to obtain a mixed coating.

[0174] Component A is diphenylmethane diisocyanate, and component B is 4,4'-diaminostilbene; and the added amount of nano-alumina is 2% of the total mass of polyurea and nano-alumina.

[0175] (4) The mixed coating obtained in step (3) is placed in a sprayer and evenly sprayed onto the surface of the pretreated aramid honeycomb material obtained in step (2) using a two-fluid atomization spraying process. After spraying, the mixture is cured for 24 hours to obtain a composite material.

[0176] Among them, in the two-fluid atomization spraying process, the fluid is air, the diameter of the mixed coating is controlled at 5μm, the pressure is 3bar, the temperature is 30℃, and the spray gun movement speed is 45cm / s.

[0177] In this embodiment, the total mass of polyurea and nano-alumina is m, the total mass of polyurea, nano-alumina and aramid honeycomb material is n, (m / n)*100%=20% (that is, in the final composite material product, the mass content of the coating composed of polyurea and nano-alumina is 20%).

[0178] Comparative Example 1

[0179] The same aramid honeycomb material as that in Example 1 (ie, the aramid honeycomb material in step (1) of Example 1) is selected.

[0180] The aramid honeycomb material of this comparative example was tested for mechanical properties, including compressive strength, L-axis shear strength, and W-axis shear strength. Compression testing was conducted in accordance with GB / T 1453, and shear testing was conducted in accordance with GB / T 1455. Three batches of test pieces were tested at room temperature (23°C ± 3°C), each containing six test pieces. The mechanical properties of the composite material prepared in Comparative Example 1 were as follows: compressive strength of 2.15 MPa, L-axis shear strength of 1.51 MPa, and W-axis shear strength of 0.83 MPa.

[0181] Comparative Example 2 (compared with Example 1, without nano-alumina)

[0182] This comparative example is basically the same as Example 1, except that:

[0183] Step (3) does not contain the content of "adding nano-alumina (with a median particle size of 50 nm) to the polyurea, stirring evenly and then performing ultrasonic dispersion treatment for 10 minutes", that is, the composite material does not contain nano-alumina.

[0184] The composite material prepared in this comparative example was tested for mechanical properties such as compressive strength, L-direction shear strength, and W-direction shear strength. The compression test was conducted in accordance with GB / T 1453, and the shear test was conducted in accordance with GB / T 1455. Three batches of test pieces were tested at room temperature (23°C ± 3°C), with each batch containing six test pieces. The mechanical properties test results of the composite material prepared in comparative example 2 were: compressive strength of 2.53 MPa, L-direction shear strength of 1.77 MPa, and W-direction shear strength of 0.96 MPa.

[0185] Comparative Example 3 (Compared with Example 1, using existing common spraying process)

[0186] This comparative example is basically the same as Example 1, except that:

[0187] The spraying in step (4) adopts the existing single fluid physical air spraying.

[0188] Step (4) is as follows: In a single-fluid physicalized air spray process, the fluid is compressed air (pressure 4 bar), and the high-speed airflow at the spray gun nozzle generates negative pressure, which sucks the mixed coating from the storage tank and atomizes it. The diameter of the mixed coating is controlled to 105 μm (achieved by adjusting the air pressure and nozzle aperture), and the atomized particles are evenly sprayed onto the treated aramid honeycomb surface.

[0189] The composite material prepared in this comparative example was tested for mechanical properties such as compressive strength, L-direction shear strength, and W-direction shear strength. The compression test was conducted in accordance with GB / T 1453, and the shear test was conducted in accordance with GB / T 1455. Three batches of test pieces were tested at room temperature (23°C ± 3°C), with each batch containing six test pieces. The mechanical property test results of the composite material prepared in comparative example 3 were: compressive strength of 2.61 MPa, L-direction shear strength of 1.74 MPa, and W-direction shear strength of 0.89 MPa.

[0190] In summary, the composite material of the embodiment of the present application, the aramid honeycomb material provides effective impact energy absorption, has lightweight characteristics, can effectively protect the lithium-ion battery module, and improve the safety and endurance performance of the entire vehicle. The polyurea coating containing nano-alumina gives the material stronger impact resistance and corrosion resistance. Compared with the existing technology, the composite material of the present application has a longer service life and more stable performance in harsh environments, which solves the shortcomings of existing materials in impact resistance and corrosion resistance. In addition, the introduction of nano-alumina can effectively improve the thermal conductivity of the material.

[0191] In this application, the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and the features of different embodiments or examples without contradiction.

[0192] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of such features. Throughout the description of this application, "plurality" means at least two, for example, two, three, etc., unless otherwise specifically defined.

[0193] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations on the present application. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present application.

Claims

1. A composite material, characterized in that It comprises an aramid honeycomb material, wherein at least a portion of the surface and / or pores of the aramid honeycomb material is provided with a coating, and the material of the coating comprises polyurea and nano-aluminum oxide.

2. The composite material according to claim 1, characterized in that The total mass content of the coating in the composite material is 0.1-99%.

3. The composite material according to claim 1, characterized in that The total mass content of the nano-aluminum oxide in the coating is 0.1-10%.

4. The composite material according to any one of claims 1 to 3, characterized in that The mass content of the nano-aluminum oxide in the coating gradually decreases from the side close to the aramid honeycomb material to the side far away from the aramid honeycomb material.

5. The composite material according to claim 4, characterized in that The coating includes a plurality of sub-coatings stacked in sequence, and the nano-alumina is evenly distributed in each of the sub-coatings; in two adjacent sub-coatings, the mass content of the nano-alumina in the sub-coating close to the aramid honeycomb material is a%, and the mass content of the nano-alumina in the sub-coating away from the aramid honeycomb material is b%, and a>b.

6. A method for preparing a composite material according to any one of claims 1 to 5, characterized in that: include: pre-treating the aramid honeycomb material to obtain a pre-treated aramid honeycomb material; Mixing the polyurea and the nano-aluminum oxide to obtain a mixed coating; The mixed coating is sprayed on the pretreated aramid honeycomb material, and then cured to obtain the composite material.

7. The method for preparing a composite material according to claim 6, characterized in that: The polyurea and the nano-aluminum oxide are mixed to obtain a mixed coating, comprising: Dividing the polyurea into multiple equal portions; Dividing the nano-alumina into the same number of parts as the polyurea according to mass; Mixing multiple portions of the nano-alumina with different masses with multiple portions of the polyurea to obtain multiple mixed coatings with different mass contents of the nano-alumina; Spraying the mixed coating on the pretreated aramid honeycomb material and then curing the mixed coating comprises: The multi-molecule mixed coating is sprayed on the pretreated aramid honeycomb material in order of decreasing mass content of the nano-alumina, and the curing is performed after each spraying.

8. The method for preparing a composite material according to claim 6, characterized in that: The spraying method is a two-fluid atomization spraying process; And / or, pre-treating the aramid honeycomb material, comprising: The aramid honeycomb material is subjected to a first washing, polishing, a second washing, and a surface activation treatment; And / or, the method for preparing the composite material further includes a step of preparing the polyurea before mixing the polyurea and the nano-alumina; the preparation of the polyurea includes: mixing polyisocyanate and polyamine in a functional group molar ratio of 1: (0.8-1.2) and stirring at -20°C to -200°C.

9. The method for preparing a composite material according to claim 6, wherein: In the two-fluid atomization spraying process, the fluid includes at least one of air, argon, and nitrogen; And / or, in the two-fluid atomization spraying process, the diameter of the mixture droplets is controlled to be 1-10 μm; And / or, the detergent used in the first washing includes ethanol and water; And / or, the polishing includes at least one of mechanical polishing and sandpaper polishing; And / or, the detergent used in the second washing includes ethanol; And / or, the surface activation treatment method includes low-temperature plasma surface activation treatment; preferably, during the low-temperature plasma surface activation treatment, the spray gun processing speed is 100-150 mm / s, the distance between the gun muzzle and the polished aramid honeycomb material is 15-20 mm, the nozzle adopts linear reciprocating motion, the processing time is 10-20 s, and the processing temperature is 50-80°C.

10. Use of the composite material according to any one of claims 1 to 5 or the composite material prepared by the preparation method according to any one of claims 6 to 9 in lightweight structural devices; Preferably, the lightweight structural device includes one of military and protective equipment, construction and infrastructure, transportation equipment, and electronic equipment.

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