High-thermal-conductivity film

Abstract

The invention relates to a high thermal conductivity film, which comprises a heat dissipation layer: the heat dissipation layer comprises hybrid particles formed by mixing a zero-dimensional structural body and a continuum, the zero-dimensional structural body is spherical structural particles prepared by sintering a metal salt solution and a template agent, and the continuum is a binder; the heat diffusion layer is made of a carbon fiber material, and quantum dot master batches are attached to carbon fibers; the polymer layer is made of thermoplastic resin; the heat diffusion layer and the polymer layer are formed on the two sides of the heat dissipation layer respectively. According to the invention, the quantum dots are adopted for manufacturing, the polyfunctionality of the quantum dots is better anchored on the carbon fibers, the surface wettability of the carbon fibers is improved, the cohesiveness of the carbon fibers and components is improved, and the mechanical strength of the film is good; the high dispersibility of the quantum dots is cooperated with the metal-based heat dissipation layer, so that the heat dissipation performance is improved; the preparation process disclosed by the invention is solvent-free and simple.

Description

Technical Field

[0001] This invention belongs to the field of materials technology, and specifically relates to a high thermal conductivity thin film. Background Technology

[0002] With the development of science and technology, society is gradually moving towards intelligence, presenting different demands for material functions. As electronic components develop towards miniaturization, integration, and high efficiency, a large amount of heat is rapidly generated and accumulated inside the components when operating at high power. If this heat cannot be dissipated in time, the operational stability of the components will be greatly affected. Therefore, the heat dissipation problem of electronic components has become a key issue for many industries. Traditional heat dissipation materials, due to their heavy weight, large size, and low thermal conductivity, are difficult to meet the heat dissipation requirements of electronic components, making it urgent to find a lightweight material with high thermal conductivity.

[0003] See patent CN 109627471A for a method for preparing a high thermal conductivity flexible membrane and its application. This patent first prepares an aqueous dispersion of hydroxylated boron nitride nanosheets and an aqueous dispersion of nanocellulose; then mixes the aqueous dispersion of hydroxylated boron nitride nanosheets and the aqueous dispersion of nanocellulose, stirs and sonicates to obtain a uniformly dispersed aqueous dispersion of hydroxylated boron nitride nanosheets / nanocellulose; then filters to remove moisture and dries at room temperature to obtain a hydroxylated boron nitride nanosheet / nanocellulose composite membrane, i.e., a high thermal conductivity flexible membrane. However, the thermal conductivity and mechanical properties of this high thermal conductivity flexible membrane still do not meet the requirements.

[0004] See patent CN116694060 A for a high thermal conductivity modified polyurethane composite film and its preparation method. This patent adds modified graphene and nanosheets to a polyurethane solution and prepares graphene by redox method. Strong oxidants such as sulfuric acid and potassium permanganate are added during the preparation process, which is complex and environmentally unfriendly. At the same time, the obtained graphene has many defects and cannot be completely reduced, resulting in residual oxygen-containing groups on the surface that reduce the intrinsic thermal conductivity of graphene. Secondly, the two-dimensional graphene is distributed in parallel in the polyurethane, which only gives the polyurethane film excellent horizontal thermal conductivity, but poor thermal conductivity in the vertical direction, which cannot meet the application requirements. Summary of the Invention

[0005] The purpose of this invention is to provide a high thermal conductivity thin film, especially a thin film with good heat expansion and heat dissipation performance and good mechanical strength.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A high thermal conductivity thin film, comprising:

[0008] Heat dissipation layer: The heat dissipation layer comprises hybrid particles of zero-dimensional structures and continuums. The zero-dimensional structures are spherical particles obtained by sintering metal salt solution and template agent, and the continuums are binders.

[0009] Heat expansion layer: The heat expansion layer is made of carbon fiber, and quantum dot masterbatch is attached to the carbon fiber;

[0010] Polymer layer: The polymer layer is made of thermoplastic resin;

[0011] The heat-expanding layer and the polymer layer are respectively formed on both sides of the heat dissipation layer.

[0012] Preferably, in the above technical solution, the mass ratio of the zero-dimensional structure to the continuum is 1:1 to 10, and the zero-dimensional structure and the continuum are hot-pressed at 200 to 300°C after being mixed.

[0013] Considering the dispersion and heat dissipation of the zero-dimensional structure in the continuum, it is further preferred that the mass ratio of the zero-dimensional structure to the continuum is 1:1 to 4.

[0014] Preferably, in the above technical solution, the zero-dimensional structure is a microspherical particle, prepared by the following method:

[0015] The solvent, metal salt, and template agent are mixed in a mass ratio of 1:0.2 to 1:0.2 to 1 to obtain a mixture. The mixture is stirred, dried, cooled, washed, filtered, and dried to obtain the zero-dimensional structure.

[0016] Considering the dispersibility and solubility of metal particles in zero-dimensional structures, and to improve particle utilization, it is further preferred that the solvent, metal salt, and template agent are in a mass ratio of 1:0.2-0.5:0.2-0.5.

[0017] More preferably, the mixture is placed in a reaction vessel, heated to 400–800°C under a nitrogen atmosphere, held for 1–3 hours, cooled, washed, filtered, and dried.

[0018] More preferably, the solvent is selected from water, methanol, ethanol, ethyl acetate, dichloromethane, and ethylene glycol, and the solvent is used to dissolve the metal salt and template agent to form a homogeneous solution.

[0019] Considering cost, it is even more preferable that the solvent is water.

[0020] More preferably, the elemental metal in the metal salt has a thermal conductivity >300W / (mk), resulting in better heat dissipation.

[0021] More preferably, the metal salt is selected from iron salt, cobalt salt, nickel salt, copper salt, zinc salt, aluminum salt, titanium salt, vanadium salt, chromium salt, manganese salt, silver salt, platinum salt, and gold salt. The metal salt can form metal particles after reacting with the template agent at high temperature, and work synergistically with the carbon fiber heat expansion layer to form a heat expansion and heat dissipation synergy.

[0022] More preferably, the metal salt is selected from one or more of copper salts and nickel salts, such as nickel nitrate and copper nitrate, wherein the mass ratio of nickel nitrate to copper nitrate is 1:1 to 5.

[0023] Considering heat dissipation, and even more preferably, the mass ratio of nickel nitrate to copper nitrate is 1:1 to 3.

[0024] More preferably, the template agent is selected from glucose, urea, melamine, chitosan, and starch.

[0025] Considering the solubility of the template agent in the solvent and the cost of the template agent, it is more preferably that the template agent is glucose.

[0026] Considering the particle size of the zero-dimensional structure, and even more preferably, the glucose is doped with sodium salt, wherein: 100 parts by weight of glucose and 1-15 parts by weight of sodium salt.

[0027] More preferably, the sodium salt is sodium chloride, sodium nitrate, sodium hydroxide, or sodium bicarbonate, with sodium chloride being the most preferred.

[0028] Preferably, in the above technical solution, the adhesive comprises organosilicon and inorganic silicon, used to disperse zero-dimensional structures to form a heat dissipation layer.

[0029] Considering the resistance to high-temperature extrusion, it is further preferred that the mass ratio of the organosilicon to the inorganic silicon is 1:0.5 to 2, and the thermally conductive film prepared after the binder is compounded has better mechanical properties and thermal conductivity.

[0030] The organosilicon is selected from polyethylene glycol organosilicon, methyltrichlorosilane, dimethyldichlorosilane, phenyltrichlorosilane, etc.;

[0031] The inorganic silicon is selected from potassium silicate, lithium silicate, and sodium silicate.

[0032] Preferably, the carbon fiber is coated with quantum dot masterbatch, such as by spraying. Quantum dots are low-dimensional semiconductor materials, and their dimensions in all three dimensions are no more than twice the exciton Bohr radius of their corresponding semiconductor materials. Therefore, they exhibit unique physical properties in terms of thermal conductivity. Quantum dots are generally spherical or near-spherical, and their diameter is usually between 2 and 20 nm. The quantum dot masterbatch is a new type of material formed by combining quantum dot materials with polymer resins. By combining quantum dots with polymer materials, the dispersibility and stability of quantum dots in the polymer matrix are improved, and they are dispersed and anchored on the carbon fiber.

[0033] More preferably, the quantum dot masterbatch comprises multi-element quantum dot masterbatch and single-element quantum dot masterbatch, wherein the ratio of multi-element quantum dot masterbatch to single-element quantum dot masterbatch is 1:1 to 30.

[0034] Considering heat transfer and cost factors, the ratio of the multi-element quantum dot masterbatch to the single-element quantum dot masterbatch is 1:1 to 20.

[0035] More preferably, the multi-element quantum dot masterbatch is selected from cadmium sulfide quantum dot masterbatch, cadmium selenide quantum dot masterbatch, cadmium telluride quantum dot masterbatch, zinc selenide quantum dot masterbatch, lead sulfide quantum dot masterbatch, lead selenide quantum dot masterbatch, indium phosphide quantum dot masterbatch, and indium arsenide quantum dot masterbatch.

[0036] Considering the bonding strength with carbon fiber, it is further preferred that the multi-element quantum dot masterbatch is a selenium and cadmium quantum dot multi-element quantum dot masterbatch.

[0037] More preferably, the single-element quantum dot masterbatch is selected from silicon quantum dot masterbatch, germanium quantum dot masterbatch, and carbon quantum dot masterbatch.

[0038] Considering the bonding strength with carbon fiber, it is further preferred that the single-element quantum dot masterbatch is a silicon quantum dot masterbatch.

[0039] More preferably, the quantum dot content of the multi-element quantum dot masterbatch is greater than 1 g / kg; the quantum dot content of the single-element quantum dot masterbatch is 0 to 1 g / kg, to ensure the stability and heat transfer performance of the quantum dots inside the polymer.

[0040] Considering dispersibility, the quantum dot content of the multi-element quantum dot masterbatch is greater than 1.5 g / kg; the quantum dot content of the single-element quantum dot masterbatch is 0 to 0.5 g / kg.

[0041] Preferably, the carbon fiber material in the above technical solution is selected from carbon fiber paper, carbon fiber cloth, carbon fiber felt, and carbon fiber woven fabric.

[0042] Considering the requirements for lightweighting and strength, the carbon fiber material is preferably carbon fiber cloth.

[0043] In the preferred embodiment of the above technical solution, the thickness of the carbon fiber layer is 0.1 to 1.5 mm. The thickness is measured by a thickness gauge, and the average value is taken after measuring the thickness at 9 different locations on the carbon fiber layer.

[0044] Considering strength requirements and cost, the carbon fiber layer thickness is preferably 0.1 to 1.0 mm.

[0045] Preferably, in the above technical solution, the tensile strength of the carbon fiber layer is greater than 1500MPa. The tensile strength is tested according to GB / T1040.1-2018. The thicker the material, the stronger its tensile strength. Considering the strength requirements and cost, it is further preferred that the tensile strength of the carbon fiber layer is greater than 2000MPa.

[0046] Preferably, the thermoplastic resin described above is selected from polyethylene terephthalate, polyethylene, polypropylene, and polyamide.

[0047] Considering tensile strength, more preferably, the thermoplastic resin is polyethylene terephthalate.

[0048] Due to the application of the above-mentioned technical solution, the present invention has the following advantages compared with the prior art:

[0049] 1. This invention uses quantum dots for fabrication. The multifunctionality of quantum dots allows for better anchoring on carbon fibers, improving the wettability of the carbon fiber surface, enhancing the adhesion between the carbon fiber and the components, and resulting in excellent film mechanical strength.

[0050] 2. The high dispersion of quantum dots in this invention, combined with the metal-based heat dissipation layer, improves heat dissipation performance;

[0051] 3. The preparation process of the present invention is solvent-free and simple. Detailed Implementation

[0052] The technical solution of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0053] Carbon fiber

[0054] A1: Carbon fiber cloth, H12K-CP160 carbon fiber cloth produced by Yixing Huaheng Enterprise, with a thickness of 0.16mm and tensile strength >2000Mpa.

[0055] A2: Carbon fiber cloth, H12K-CP100 carbon fiber cloth produced by Yixing Huaheng Enterprise, with a thickness of 0.1mm and tensile strength >2000Mpa.

[0056] Quantum dot masterbatch

[0057] B1: Single-element quantum dot masterbatch, CQD-515 carbon quantum dot masterbatch produced by Xiamen Bohr Technology Co., Ltd., with a quantum dot content of 0.4g / kg;

[0058] B2: Multi-element quantum dot masterbatch, QG3M537 selenium and cadmium quantum dot masterbatch produced by Xiamen Bohr Technology Co., Ltd., with a quantum dot content of 2.7g / kg.

[0059] Table 1:

[0060]

[0061] The heat expansion layers (M1-M6) are prepared according to the formulation described in Table 1. After weighing the quantum dot masterbatch, they are sprayed onto the surface of the carbon fiber. The heat expansion layer M7 is left untreated.

[0062] Metal salts

[0063] C1: Copper nitrate, specifically C140879 copper nitrate produced by Aladdin Reagent Company;

[0064] C2: Nickel nitrate, N140967 nickel nitrate produced by Aladdin Reagent Company.

[0065] Template agent

[0066] D1: Glucose, L115560 glucose produced by Aladdin Reagent Company;

[0067] D2: Sodium chloride, Aladdin Reagent Company's C111547 sodium chloride.

[0068] Solvent

[0069] E: Deionized water.

[0070] Table 2:

[0071]

[0072]

[0073] Zero-dimensional structures (N1-N9) are prepared by mixing metal salts, template agents, and solvents according to the formulations described in Table 2, dissolving them to obtain a mixture, stirring and drying the mixture at 80-100°C, placing the mixture in a reaction vessel, heating it to 600-800°C under a nitrogen atmosphere, holding it for 1-3 hours, cooling, washing, filtering, and drying.

[0074] [Continuum]

[0075] F1: Polyethylene glycol silicone, aminoPEG silane PS2-NL-10k produced by Shanghai Pengshuo Biotechnology Co., Ltd.;

[0076] F2: Potassium silicate, produced by Luoyang Tongrun Information Technology Co., Ltd. (TRUNNANG potassium silicate powder)

[0077] Polymer layer

[0078] G: PET film, P40A PET film produced by Dongguan Kangfuxiang Plastic & Electronic Co., Ltd.

[0079] Table 3:

[0080]

[0081]

[0082] Examples 1-19 and Comparative Examples 1 and 2 prepared high thermal conductivity films according to the formulations shown in Table 3. First, hybrid particles were prepared, weighed according to the formulations shown in the table, and mixed in a high-speed ball mill. Then, they were hot-pressed at 200-300°C. During the hot-pressing process, the heat expansion layer and the heat dissipation layer were in contact on one side and served as the bottom film. The composite was then calendered. Then, the polymer layer was attached to the other side of the heat expansion layer, and the hot-pressing continued at a temperature of 200-300°C.

[0083] Comparative Example 3 prepared a high thermal conductivity film according to the formulation shown in Table 3, and attached the polymer layer to one side of the heat expansion layer by hot pressing at a temperature of 200-300℃.

[0084] Comparative Example 4 prepared a high thermal conductivity thin film according to the formulation shown in Table 3. First, hybrid particles were prepared, weighed according to the formulation shown in the table, and mixed in a high-speed ball mill. Then, the mixture was hot-pressed at 200-300°C. During the hot-pressing process, the polymer layer was in contact with the heat dissipation layer and served as the bottom film. The film was prepared by calendering and composite.

[0085] The following tests were performed on the composite material. Unless otherwise specified, all tests were conducted at 25°C. The main indicators are as follows:

[0086] 1. Tensile strength: Tested according to GB / T 1040.1-2018, the specimen is stretched at a rate of 5 mm / min, and the specimen size is 100 mm × 10 mm.

[0087] 2. Thermal conductivity: Tested according to national standard GB / T 10297-2015, with sample size of 40mm×80mm×120mm, thermocouple measurement spacing of 60mm, and heating power of 2KW / h.

[0088] Table 4:

[0089] Examples and Comparative Examples Tensile strength (MPa) Thermal conductivity W / (m·K) Example 1 388 970 Example 2 402 982 Example 3 347 868 Example 4 352 880 Example 5 316 742 Example 6 322 786 Example 7 306 735 Example 8 308 740 Example 9 351 878 Example 10 315 749 Example 11 320 792 Example 12 355 888 Example 13 336 840 Example 14 383 958 Example 15 374 935 Example 16 358 895 Example 17 368 920 Example 18 371 928 Comparative Example 1 295 730 Comparative Example 2 284 710 Comparative Example 3 204 510 Comparative Example 4 127 318

[0090] As shown in Table 4, compared with the comparative examples, the films prepared in the examples have better thermal conductivity, with thermal conductivity coefficients of 730 W / (m·K) or higher. They also have superior mechanical properties, with tensile strengths of 305 MPa or higher. The film preparation process of the examples is simple and convenient, pollution-free, and easy for large-scale production.

[0091] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A high thermal conductivity thin film, characterized in that: include: Heat dissipation layer: The heat dissipation layer comprises hybrid particles of zero-dimensional structures and continuums. The zero-dimensional structures are spherical particles obtained by sintering metal salt solution and template agent, and the continuums are binders. Heat expansion layer: The heat expansion layer is made of carbon fiber, and quantum dot masterbatch is attached to the carbon fiber; Polymer layer: The polymer layer is made of thermoplastic resin; The heat-expanding layer and the polymer layer are respectively formed on both sides of the heat dissipation layer.

2. The high thermal conductivity thin film according to claim 1, characterized in that: The mass ratio of the zero-dimensional structure to the continuum is 1:1 to 10, and the zero-dimensional structure and the continuum are mixed and then hot-pressed at 200 to 300°C.

3. The high thermal conductivity thin film according to claim 1, characterized in that: The zero-dimensional structure is prepared by the following method: a solvent, a metal salt, and a template agent are mixed in a mass ratio of 1:0.2 to 1:0.2 to 1, dissolved to obtain a mixture, stirred, dried, cooled, washed, filtered, and dried to obtain the zero-dimensional structure.

4. The high thermal conductivity thin film according to claim 3, characterized in that: The solvent is selected from water, methanol, ethanol, ethyl acetate, dichloromethane, and ethylene glycol; The thermal conductivity of the elemental metal in the metal salt is >300W / (mk), and the metal salt is selected from iron salt, cobalt salt, nickel salt, copper salt, zinc salt, aluminum salt, titanium salt, vanadium salt, chromium salt, manganese salt, silver salt, platinum salt, and gold salt. The template agent is selected from glucose, urea, melamine, chitosan, and starch.

5. The high thermal conductivity thin film according to claim 4, characterized in that: The metal salts are nickel nitrate and copper nitrate, and the mass ratio of nickel nitrate to copper nitrate is 1:1 to 5. The template agent, glucose-doped sodium salt, comprises: 100 parts by weight of glucose and 1 to 15 parts by weight of sodium salt.

6. The high thermal conductivity thin film according to claim 1, characterized in that: The adhesive comprises organosilicon and inorganic silicon, wherein the mass ratio of organosilicon to inorganic silicon is 1:0.5 to 2; The organosilicon is selected from polyethylene glycol organosilicon, methyltrichlorosilane, dimethyldichlorosilane, phenyltrichlorosilane, etc.; The inorganic silicon is selected from potassium silicate, lithium silicate, and sodium silicate.

7. The high thermal conductivity thin film according to claim 1, characterized in that: The quantum dot masterbatch includes multi-element quantum dot masterbatch and single-element quantum dot masterbatch, and the ratio of multi-element quantum dot masterbatch to single-element quantum dot masterbatch is 1:1 to 30.

8. The high thermal conductivity thin film according to claim 7, characterized in that: The multi-element quantum dot masterbatch is selected from cadmium sulfide quantum dot masterbatch, cadmium selenide quantum dot masterbatch, cadmium telluride quantum dot masterbatch, zinc selenide quantum dot masterbatch, lead sulfide quantum dot masterbatch, lead selenide quantum dot masterbatch, indium phosphide quantum dot masterbatch, and indium arsenide quantum dot masterbatch. The single-element quantum dot masterbatch is selected from silicon quantum dot masterbatch, germanium quantum dot masterbatch, and carbon quantum dot masterbatch.

9. The high thermal conductivity thin film according to claim 7, characterized in that: The quantum dot content of the multi-element quantum dot masterbatch is greater than 1 g / kg; the quantum dot content of the single-element quantum dot masterbatch is 0 to 1 g / kg.

10. The high thermal conductivity thin film according to claim 1, characterized in that: The carbon fiber material is selected from carbon fiber paper, carbon fiber cloth, carbon fiber felt, and carbon fiber woven fabric; The thermoplastic resin is selected from polyethylene terephthalate, polyethylene, polypropylene, and polyamide.

Images