Double-layer composite aluminum foil and preparation method thereof

Abstract

The invention is applied to the technical field of composite aluminum foils, and discloses a preparation method of a double-layer composite aluminum foil. The preparation method of the composite aluminum foil comprises the following steps: 1, preparing the following raw materials in parts by weight: 35-45 parts of a monofunctional thermocuring oligomer, 55-75 parts of a water-borne epoxy resin oligomer, 4-8 parts of nano boron nitride, 2-4 parts of hollow glass beads, 0.8-2.5 parts of a thermal initiator and 2-4 parts of a nonionic emulsifier. According to the preparation method of the double-layer composite aluminum foil, the nano boron nitride and the hollow glass beads are adopted, the nano boron nitride has high thermal conductivity and can be better combined with other materials after organic modification, the overall thermal conductivity is improved, the hollow glass beads are subjected to a special preparation process, silane coupling agent modified carbon nanotubes are introduced, and the thermal conductivity of the aluminum foil is improved. And due to the synergistic effect with the nano boron nitride, the composite aluminum foil has an efficient heat conduction effect.

Description

Technical Field

[0001] The invention relates to the technical field of composite aluminum foil, in particular to a double-layer composite aluminum foil and a preparation method thereof. Background Art

[0002] In today's era of rapid technological development, aluminum foil, as a widely used material, plays an important role in many fields. However, traditional aluminum foil has gradually exposed some shortcomings in terms of thermal conductivity and sound insulation. In the field of electronic equipment, with the continuous improvement of the integration of electronic components, heat dissipation has become a key factor restricting equipment performance and stability. Although traditional aluminum foil has a certain thermal conductivity, its thermal conductivity is insufficient when dealing with the large amount of heat generated by high-power electronic components. The heat cannot be dissipated in a timely and effective manner, which may cause the temperature of electronic components to be too high, thereby reducing the working efficiency of the equipment and even shortening the service life of the equipment. In addition, in some high-end electronic products, there are also strict requirements for noise control. The performance of traditional aluminum foil in sound insulation is not satisfactory and cannot provide a sound insulation solution for electronic products. The equipment provides a quiet working environment. In the automotive industry, aluminum foil is also widely used in automobile heat insulation and sound insulation. However, the existing aluminum foil materials are difficult to effectively block various noises such as engine noise, wind noise and tire noise during high-speed driving of the car, affecting the riding comfort of passengers in the car. At the same time, in high-temperature areas such as the engine compartment of the car, the thermal conductivity of traditional aluminum foil is limited and the heat cannot be quickly transferred out, which may cause the engine to overheat and affect the performance and safety of the car. In the field of construction, aluminum foil is often used as heat insulation and sound insulation materials, but the existing aluminum foil products are difficult to meet people's needs for a quiet living and working environment in terms of sound insulation. For example, in buildings close to major traffic routes, external noise can easily pass through traditional aluminum foil materials into the room, affecting people's quality of life and work;

[0003] From the perspective of preparation methods, the preparation processes of the composite aluminum foil products currently available on the market are often relatively simple. Usually, a single material combination is used to prepare the composite aluminum foil through mechanical pressing or a simple coating process. Although this preparation method has low cost, the resulting composite aluminum foil has great limitations in performance. For example, the bonding force between the materials is not strong, and it is easy to have problems such as stratification and falling off during use. In addition, due to the selection of materials and process limitations, it is impossible to effectively regulate the thermal conductivity and sound insulation performance. In terms of material selection, the existing composite aluminum foil is mainly composed of ordinary metal aluminum and some common polymer materials. These materials have natural deficiencies in thermal conductivity and sound insulation performance. For example, although some polymer materials have certain flexibility and processability, their thermal conductivity is poor, and although metal aluminum has good thermal conductivity, its sound insulation effect is poor. In addition, the existing material combinations often lack innovation and cannot give full play to the synergistic effect between different materials to achieve better thermal conductivity and sound insulation effects. Summary of the invention

[0004] The object of the present invention is to provide a double-layer composite aluminum foil and a preparation method thereof, so as to solve the problem of poor sound insulation and thermal conductivity of the existing double-layer composite aluminum foil mentioned in the above background technology.

[0005] To achieve the above object, the present invention provides the following technical solution: a method for preparing a double-layer composite aluminum foil, the method for preparing the composite aluminum foil comprising the following steps:

[0006] Step 1: Prepare the following raw materials by weight: 35-45 parts of monofunctional thermosetting oligomer, 55-75 parts of waterborne epoxy resin oligomer, 4-8 parts of nano boron nitride, 2-4 parts of hollow glass microspheres, 0.8-2.5 parts of thermal initiator and 2-4 parts of non-ionic emulsifier;

[0007] Step 2: Mix the raw materials in the first step and dilute with water to prepare a coating with a mass fraction of 0.8%, and apply the coating to the surface of the aluminum foil substrate with a coating thickness of 8-12 μm;

[0008] Step 3: Place the side of the aluminum foil substrate coated with the coating in the second step toward the surface of another aluminum foil substrate and accurately bond them together, and perform thermal radiation curing at a temperature of 170-230° C. and a wavelength of 0.75-2 μm for 2-4 minutes to obtain a composite aluminum foil;

[0009] The monofunctional heat-curable oligomer is a monofunctional acrylate oligomer;

[0010] The waterborne epoxy resin oligomer is an oligomer obtained by water-based treatment of bisphenol A epoxy resin, and the average polymerization degree of the oligomer is 0-1.8;

[0011] The thermal initiator is benzoyl peroxide;

[0012] The nonionic emulsifier is fatty alcohol polyoxyethylene ether;

[0013] The nano boron nitride is prepared by the following steps:

[0014] S1. Add melamine, catechol, glycidyl methacrylate and N,N-dimethylformamide into a flask, heat to 65°C and stir to react for 10 hours to obtain component A;

[0015] S2, adding nano boron nitride into ethanol and uniformly dispersing by ultrasonication to obtain a boron nitride suspension;

[0016] S3. Add hexamethylene diisocyanate and ethanol into the flask, stir magnetically and heat to 50°C, then slowly drop the boron nitride suspension.

[0017] S4, after the dropwise addition is completed, add component A and stannous octoate, keep warm and stir to react for 6-8 hours to obtain nano boron nitride;

[0018] The hollow glass microspheres are made by the following steps:

[0019] S1. Add polyacrylamide and N-methylpyrrolidone into a flask, heat to 95°C and stir to dissolve;

[0020] S2, adding the carbon nanotube aqueous solution modified by the silane coupling agent under stirring, and continuing stirring for 10 hours;

[0021] S3, removing water by vacuum distillation to obtain a spinning solution, and performing dry spinning;

[0022] S4. The obtained primary fibers are soaked in ethanol for 20 hours, vacuum dried, and heat stretched at 160° C. with a stretching ratio of 4-5 times, and then sheared to obtain hollow glass microbeads with a length of 1-4 mm.

[0023] Preferably, the molar ratio of melamine to glycidyl methacrylate is 1:1.1-1.3.

[0024] Preferably, the amount of catechol used is 0.04-0.08% of the mass of glycidyl methacrylate.

[0025] Preferably, the amount ratio of the boron nitride suspension, hexamethylene diisocyanate, ethanol, component A and stannous octoate is 20 mL:7 g:12 mL:3-4.5 g:0.15 mL.

[0026] Preferably, the dosage ratio of nano boron nitride to ethanol in the boron nitride suspension is 1-2 g:20 mL.

[0027] Preferably, the degree of polymerization of the polyacrylamide is 1600-1700, and the degree of hydrolysis is 95-98%.

[0028] Preferably, the mass ratio of the polyacrylamide, N-methylpyrrolidone and the carbon nanotube aqueous solution modified by the silane coupling agent is 18-23:60-75:8-20.

[0029] Preferably, the silane coupling agent-modified carbon nanotube aqueous solution is prepared by ultrasonically mixing the silane coupling agent-modified carbon nanotubes and deionized water in a dosage ratio of 2-2.8 g:8-18 mL.

[0030] Preferably, the spinneret extrusion rate of the dry spinning process is 3.5-3.8 mL / min, the spinning temperature is 80-85° C., and the spinneret aperture is 0.28-0.30 mm.

[0031] Compared with the prior art, the invention has the following beneficial effects: the preparation method of the double-layer composite aluminum foil:

[0032] 1. Nano boron nitride and hollow glass microspheres are used. Nano boron nitride has high thermal conductivity. After organic modification, it can be better combined with other materials to improve the overall thermal conductivity. Hollow glass microspheres are prepared by a special process and carbon nanotubes modified with silane coupling agents are introduced to enhance their thermal conductivity. The synergistic effect with nano boron nitride makes the composite aluminum foil have a high-efficiency thermal conductivity.

[0033] Furthermore, since the hollow glass microspheres themselves have certain sound insulation properties, the hollow glass microspheres obtained through a specific preparation process can effectively reduce noise transmission while ensuring thermal conductivity;

[0034] 2. Using a variety of raw materials such as monofunctional thermosetting oligomers, water-based epoxy resin oligomers, nano-boron nitride, hollow glass microspheres, thermal initiators and non-ionic emulsifiers, the raw materials cooperate with each other and play a synergistic role, providing a basis for achieving efficient thermal conductivity and sound insulation effects.

[0035] Furthermore, component A is prepared from raw materials such as melamine, catechol, and glycidyl methacrylate, and then reacted with nano-boron nitride to obtain organically modified nano-boron nitride. This modification method improves the dispersibility and stability of nano-boron nitride in the coating, allowing it to better exert its thermal conductivity, while also enhancing its bonding with other materials.

[0036] Furthermore, hollow glass microspheres are prepared by using an aqueous solution of carbon nanotubes modified with polyacrylamide, N-methylpyrrolidone and a silane coupling agent, so that the hollow glass microspheres obtained through the steps of dry spinning, ethanol impregnation, vacuum drying and heat stretching have uniform size, good thermal conductivity and a hollow structure, which helps to improve the sound insulation effect;

[0037] 3. The raw materials are mixed and diluted with water to prepare a coating and then thermally cured at a specific temperature and wavelength. This process condition can ensure that the coating is evenly coated on the surface of the substrate, with a fast curing speed, and improve production efficiency. At the same time, the performance of the composite aluminum foil is stable, and the entire preparation process is easy to control and highly repeatable, which is conducive to large-scale production and promotion and application. DETAILED DESCRIPTION

[0038] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0039] The invention provides a technical solution: a method for preparing a double-layer composite aluminum foil.

[0040] Example

[0041] Raw material preparation: Take 40 parts of monofunctional thermosetting oligomer.

[0042] - Take 65 parts of waterborne epoxy resin oligomer.

[0043] -Take 6 portions of nano boron nitride.

[0044] -Take 3 portions of hollow glass microspheres.

[0045] -Take 1.5 parts of thermal initiator.

[0046] - Take 3 parts of non-ionic emulsifier.

[0047] The monofunctional heat-curable oligomer is a monofunctional acrylate oligomer;

[0048] The waterborne epoxy resin oligomer is an oligomer obtained by water-based treatment of bisphenol A epoxy resin, and the average polymerization degree of the oligomer is 0-1.8;

[0049] The thermal initiator is benzoyl peroxide;

[0050] The nonionic emulsifier is fatty alcohol polyoxyethylene ether;

[0051] Coating preparation:

[0052] The above raw materials are mixed, and diluted with water to prepare a coating with a mass fraction of 0.8%.

[0053] Coating and curing:

[0054] The coating was applied to the surface of the substrate with a coating thickness of 10 μm.

[0055] Thermal radiation curing was carried out at a temperature of 195° C. and a wavelength of 1.25 μm for 3 minutes to obtain a composite aluminum foil.

[0056] Preparation of organically modified nano boron nitride:

[0057] Step 1: Add melamine, catechol, glycidyl methacrylate and N,N-dimethylformamide into a flask, heat to 65°C and stir to react for 10 hours to obtain component A, wherein the molar ratio of melamine to glycidyl methacrylate is 1:1.2, and the amount of catechol is 0.06% of the mass of glycidyl methacrylate.

[0058] Step 2: Add 1.5g of nano-boron nitride to 30mL of ethanol and disperse it evenly by ultrasonication to obtain a boron nitride suspension. Add 7g of hexamethylene diisocyanate and 12mL of ethanol to a flask, stir magnetically and heat to 50°C, slowly drop the boron nitride suspension, add 4g of component A and 0.15mL of stannous octoate after the addition is completed, keep warm and stir to react for 7h to obtain organically modified nano-boron nitride.

[0059] After the preparation is completed, the organically modified nano boron nitride is tested. The unmodified nano boron nitride may have poor dispersibility in some solvents, but after organic modification, its dispersibility in the corresponding solvents will be improved due to the introduction of solvent-philic functional groups. During the test, the unmodified and modified nano boron nitride are added to ethanol, acetone, dimethylformamide and tetrahydrofuran respectively to observe their dispersion. If the dispersibility of the modified nano boron nitride in the solvent is significantly improved compared with that before organic modification, it can be proved that the organic modification is successful.

[0060] The following table shows the dispersibility test data of organically modified nano boron nitride

[0061]

[0062] By testing the dispersibility of unmodified and organically modified nano-boron nitride in different solvents, the following conclusions can be drawn:

[0063] In solvents such as ethanol, acetone, dimethylformamide (DMF) and tetrahydrofuran (THF), unmodified nano-boron nitride generally has different degrees of agglomeration and poor dispersibility. After organic modification, the dispersibility of nano-boron nitride in these solvents has been significantly improved due to the introduction of solvent-philic functional groups. In the experiment, the modified nano-boron nitride is evenly dispersed in ethanol without obvious agglomeration; it is well dispersed in acetone and the solution is relatively clear; it is completely dispersed in DMF to form a stable suspension; it is evenly dispersed in THF without precipitation for a long time, which proves that organic modification can effectively improve the dispersibility of nano-boron nitride in the corresponding solvents.

[0064] Preparation of hollow glass microspheres:

[0065] 20 parts of polyacrylamide with a degree of polymerization of 1650 and a degree of hydrolysis of 97% and 68 parts of N-methylpyrrolidone were added into a flask, and the temperature was raised to 95°C and stirred to dissolve.

[0066] Under stirring, an aqueous solution of carbon nanotubes modified with a silane coupling agent prepared by ultrasonically mixing 2.4 g of carbon nanotubes modified with a silane coupling agent and 15 mL of deionized water was added, and stirring was continued for 10 h.

[0067] Water was removed by distillation under reduced pressure to obtain a spinning solution, which was then dry-spun with a spinneret extrusion rate of 3.6 mL / min, a spinning temperature of 82° C., and a spinneret aperture of 0.29 mm.

[0068] The obtained primary fibers were soaked in ethanol for 20 hours, vacuum dried, and heat stretched at 160° C. with a stretching ratio of 4.5 times. Hollow glass microbeads with a length of 2-3 mm were obtained by shearing.

[0069] Table 1 Specific components of the experimental examples in the composite aluminum foil performance test

[0070] Sample No. Thermal initiator Hollow glass beads Experimental Example 1 0.8 parts 2 servings Experimental Example 2 0.8 parts 3 servings Experimental Example 3 0.8 parts 4 servings Experimental Example 4 1.5 servings 2 servings Experimental Example 5 1.5 servings 3 servings Experimental Example 6 1.5 servings 4 servings Experimental Example 7 2.5 servings 2 servings Experimental Example 8 2.5 servings 3 servings Experimental Example 9 2.5 servings 4 servings

[0071] Table 2 Test data of the experimental example in the composite aluminum foil performance test

[0072] Sample No. Thermal conductivity W / (m·k) Sound insulation(db) Experimental Example 1 210 32 Experimental Example 2 210 35 Experimental Example 3 210 34 Experimental Example 4 230 32 Experimental Example 5 230 35 Experimental Example 6 230 34 Experimental Example 7 225 32 Experimental Example 8 225 35 Experimental Example 9 225 34

[0073] The above specific embodiments further illustrate the purpose, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above are only specific embodiments of the present invention and do not limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention are included in the protection scope of the present invention.

Claims

1. A method for preparing a double-layer composite aluminum foil, characterized in that: The preparation method of the composite aluminum foil comprises the following steps: Step 1: Prepare the following raw materials by weight: 35-45 parts of monofunctional thermosetting oligomer, 55-75 parts of waterborne epoxy resin oligomer, 4-8 parts of nano boron nitride, 2-4 parts of hollow glass microspheres, 0.8-2.5 parts of thermal initiator and 2-4 parts of non-ionic emulsifier; Step 2: Mix the raw materials in the first step and dilute with water to prepare a coating with a mass fraction of 0.8%, and apply the coating to the surface of the aluminum foil substrate with a coating thickness of 8-12 μm; Step 3: Place the side of the aluminum foil substrate coated with the coating in the second step toward the surface of another aluminum foil substrate and accurately bond them together, and perform thermal radiation curing at a temperature of 170-230° C. and a wavelength of 0.75-2 μm for 2-4 minutes to obtain a composite aluminum foil; The monofunctional heat-curable oligomer is a monofunctional acrylate oligomer; The waterborne epoxy resin oligomer is an oligomer obtained by water-based treatment of bisphenol A epoxy resin, and the average polymerization degree of the oligomer is 0-1.8; The thermal initiator is benzoyl peroxide; The nonionic emulsifier is fatty alcohol polyoxyethylene ether; The nano boron nitride is prepared by the following steps: S1. Add melamine, catechol, glycidyl methacrylate and N,N-dimethylformamide into a flask, heat to 65°C and stir to react for 10 hours to obtain component A; S2, adding nano boron nitride into ethanol and uniformly dispersing by ultrasonication to obtain a boron nitride suspension; S3. Add hexamethylene diisocyanate and ethanol into the flask, stir magnetically and heat to 50°C, then slowly drop the boron nitride suspension. S4, after the dropwise addition is completed, add component A and stannous octoate, keep warm and stir to react for 6-8 hours to obtain nano boron nitride; The hollow glass microspheres are made by the following steps: S1. Add polyacrylamide and N-methylpyrrolidone into a flask, heat to 95°C and stir to dissolve; S2, adding the carbon nanotube aqueous solution modified by the silane coupling agent under stirring, and continuing stirring for 10 hours; S3, removing water by vacuum distillation to obtain a spinning solution, and performing dry spinning; S4. The obtained primary fibers are soaked in ethanol for 20 hours, vacuum dried, and heat stretched at 160° C. with a stretching ratio of 4-5 times, and then sheared to obtain hollow glass microbeads with a length of 1-4 mm.

2. The method for preparing a double-layer composite aluminum foil according to claim 1, characterized in that: The molar ratio of melamine to glycidyl methacrylate is 1:1.1-1.

3.

3. The method for preparing a double-layer composite aluminum foil according to claim 1, characterized in that: The amount of catechol used is 0.04-0.08% of the mass of glycidyl methacrylate.

4. The method for preparing a double-layer composite aluminum foil according to claim 1, characterized in that: The dosage ratio of the boron nitride suspension, hexamethylene diisocyanate, ethanol, component A and stannous octoate is 20 mL: 7 g: 12 mL: 3-4.5 g: 0.15 mL.

5. The method for preparing a double-layer composite aluminum foil according to claim 1, characterized in that: The dosage ratio of nano boron nitride to ethanol in the boron nitride suspension is 1-2 g:20 mL.

6. The method for preparing a double-layer composite aluminum foil according to claim 1, characterized in that: The polymerization degree of the polyacrylamide is 1600-1700, and the hydrolysis degree is 95-98%.

7. The method for preparing a double-layer composite aluminum foil according to claim 1, characterized in that: The mass ratio of the polyacrylamide, N-methylpyrrolidone and the carbon nanotube aqueous solution modified by the silane coupling agent is 18-23:60-75:8-20.

8. The method for preparing a double-layer composite aluminum foil according to claim 1, characterized in that: The silane coupling agent modified carbon nanotube aqueous solution is prepared by ultrasonically mixing the silane coupling agent modified carbon nanotubes and deionized water in a dosage ratio of 2-2.8 g:8-18 mL.

9. The method for preparing a double-layer composite aluminum foil according to claim 1, characterized in that: The spinneret extrusion rate of the dry spinning process is 3.5-3.8 mL / min, the spinning temperature is 80-85° C., and the spinneret aperture is 0.28-0.30 mm.

10. A double-layer composite aluminum foil, characterized in that: The double-layer composite aluminum foil is prepared by the method according to any one of claims 1 to 9.

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