PCB (Printed Circuit Board) material with high heat dissipation performance and preparation method

Abstract

The invention belongs to the field of PCBs (printed circuit boards), and provides a PCB material with high heat dissipation performance and a preparation method thereof.The PCB material adopts a multi-layer composite structure design and comprises a circuit board layer, a heat conduction insulating layer, a metal bottom layer, a silica gel-based heat conduction glue layer, a heat dissipation layer and heat dissipation fins, wherein the heat conduction insulating layer is a polyimide composite material in which hexagonal boron nitride nanosheets are oriented in parallel, and the heat dissipation layer is formed by coating an aluminum nitride reinforced aluminum-based composite material with a titanium nitride transition layer and is integrally die-cast with the heat dissipation fins. Through key technologies such as surface modified boron nitride nanosheet suction filtration orientation, polyamide acid dipping curing, heat dissipation assembly preparation through a coating-in-situ nitriding-die casting process and overall hot pressing assembly, the excellent heat conduction performance of the heat conduction insulating layer in the plane direction is achieved; the problems of low heat dissipation efficiency, poor device reliability and the like caused by insufficient heat-conducting property and insulating property of a traditional PCB material are solved, and the material has wide application value.

Description

Technical Field

[0001] The present invention belongs to the field of PCB circuit boards and provides a PCB circuit board material with high heat dissipation performance and a preparation method thereof. Background Art

[0002] As modern electronic devices advance toward higher power density, miniaturization, and integration, printed circuit boards (PCBs), the core carriers of these devices, face unprecedented heat dissipation challenges. In high-power applications such as high-end servers, 5G communications equipment, electric vehicle controllers, and LED lighting systems, electronic components generate significant amounts of heat during operation. The limited heat dissipation capacity of traditional PCB materials has become a key bottleneck restricting system performance and reliability. To ensure stable operation and extend the lifespan of electronic devices, PCB materials must possess excellent thermal conductivity, enabling rapid heat transfer from the heat source to the heat sink or the surrounding environment, while also maintaining good electrical insulation properties to prevent short circuits and signal interference. Furthermore, the materials must possess excellent mechanical strength, dimensional stability, and process compatibility to meet the requirements of complex circuit layouts and demanding operating environments. The development of PCB materials with high heat dissipation performance is crucial for increasing the power density, reducing the size and weight, and improving energy efficiency and reliability of electronic products. These materials are key technological enablers for driving the electronic information industry toward higher performance and higher levels of integration. They also provide a crucial material foundation for emerging applications such as artificial intelligence chips and quantum computing.

[0003] Despite the continuous advancement of PCB heat dissipation material technology, current research and industrialization levels still face significant deficiencies, primarily in the coordinated optimization of thermal conductivity and insulation properties. While traditional FR-4 glass-fiber-reinforced epoxy resin substrates offer excellent insulation and mechanical strength, their thermal conductivity is only 0.3-0.4 W / m·K, far from meeting the heat dissipation requirements of high-power devices. This leads to heat accumulation and device failure due to overheating. While existing metal-based PCBs have improved thermal conductivity, the interfacial thermal resistance between the metal and insulation layers is high, and increasing the thickness of the insulation layer significantly reduces overall thermal efficiency. Furthermore, there are challenges such as poor thermal expansion coefficient matching and complex processing. While the addition of thermally conductive fillers such as boron nitride and aluminum oxide to filled thermally conductive insulating materials can improve thermal conductivity to a certain extent, uneven filler dispersion and poor orientation result in low thermal efficiency. Furthermore, high filler loadings degrade the material's mechanical and processing properties. For example, Chinese patent publication number CN104378910A discloses a heat-dissipating PCB board, but it suffers from shortcomings such as uneven distribution of thermally conductive fillers within the matrix and poor interface bonding. Furthermore, existing heat dissipation structure designs lack systematic consideration, resulting in suboptimal heat conduction paths between material layers and immature interface thermal resistance control technology, making it difficult to achieve ideal overall heat dissipation. Summary of the Invention

[0004] (1) Technical problems solved The purpose of the present invention is to provide a PCB circuit board material with high heat dissipation performance and a preparation method thereof, so as to solve the problem that the current PCB circuit board materials have insufficient thermal conductivity and insulation performance.

[0005] (2) Technical solution In order to achieve the above object, the present invention provides the following technical solutions: A PCB circuit board material with high heat dissipation performance, characterized by comprising a circuit board layer, a heat-conducting insulating layer, a metal bottom layer, a silicone-based thermally conductive adhesive layer, a heat dissipation layer, and a heat sink stacked sequentially from top to bottom, wherein: The circuit board layer is a FR-4 glass fiber reinforced epoxy resin substrate with a copper clad thickness of 35~70μm and a SAC305 lead-free tin-silver-copper alloy positioning platform is set on its surface; The thermal insulation layer is a polyimide layered composite material with a thickness of 50 to 200 μm, in which the hexagonal boron nitride nanosheets are arranged parallel to the plane of the thermal insulation layer, and the orientation degree of the hexagonal boron nitride nanosheets is 85 to 98%; The metal base is T2 copper or 6061 aluminum alloy with a thickness of 1.0~3.0mm; The heat dissipation layer is an aluminum nitride reinforced aluminum matrix composite material and the surface of the aluminum nitride particles has a titanium nitride transition layer; The heat sink and the heat dissipation layer are integrally die-casted with the same aluminum-based composite material and are arranged on the lower surface of the heat dissipation layer.

[0006] The present invention adopts a multi-layer composite structure design mainly used to enhance the thermal conductivity and heat dissipation performance of PCB circuit board materials. The core design concept of the technical solution of the present invention is to achieve an efficient heat conduction path from the circuit board layer to the heat sink through a carefully constructed layered composite structure, and maximize the overall heat dissipation efficiency through the optimized selection of materials for each functional layer and interface engineering. The circuit board layer adopts a copper-clad FR-4 glass fiber reinforced epoxy resin substrate as the basic carrier. While maintaining the excellent electrical performance of traditional PCBs, the local thermal conductivity is enhanced by the SAC305 lead-free tin-silver-copper alloy positioning platform set on the surface, creating a good starting point for subsequent heat conduction. The thermal conductive insulation layer is the key innovation of the entire design. Boron nitride composite filler polyimide layered composite material is selected, in which hexagonal boron nitride nanosheets are arranged in a highly ordered parallel orientation through a special process. This orientation structure fully utilizes the inherent anisotropic thermal conductivity of boron nitride to form a continuous thermal conductive network in the plane direction. At the same time, the polyimide matrix provides excellent insulation performance and mechanical support. The combination of the two achieves the synergistic optimization of thermal conductivity and insulation performance. The metal bottom layer uses high thermal conductivity T2 copper or 6061 aluminum alloy as an important heat conduction relay layer. Its excellent thermal conductivity ensures that heat can be quickly transferred from the thermal insulation layer to the subsequent heat dissipation structure. The setting of the silicone-based thermal conductive adhesive layer eliminates the contact thermal resistance between different material layers, and ensures the continuity of the heat conduction path through its good interface wettability and thermal conductivity. The heat dissipation layer design uses aluminum nitride reinforced aluminum-based composite materials. The design of the titanium nitride transition layer on the surface of the aluminum nitride particles is of great significance. This transition layer not only improves the interface bonding between aluminum nitride and the aluminum matrix, reduces the interface thermal resistance, but also enhances the overall thermal conductivity and mechanical properties of the composite material. The design of the heat sink and the heat dissipation layer being integrally die-cast with the same material eliminates the contact thermal resistance in the traditional separate structure and forms a continuous heat conduction channel. At the same time, the fin structure of the heat sink greatly increases the heat exchange area with the environment. Through the matching design of material properties and optimization of interface engineering, the entire multi-layer structure forms a synergistic effect in thermal conductivity of each layer of material, allowing heat to be efficiently transferred along the optimized conduction path and finally quickly dissipated into the environment through the heat sink, thus achieving an overall heat dissipation effect that far exceeds the performance of a single material.

[0007] Furthermore, the thermally conductive insulating layer is formed by filtering 40.0-70.0 parts of boron nitride nanosheets whose surfaces are modified with 3-aminopropyltriethoxysilane to form a porous oriented structure, then impregnating polyamic acid and pre-drying it at 80-120°C in a nitrogen atmosphere for 30-60 minutes, and then curing it in three steps at 140-145°C, 280-290°C, and 350-360°C.

[0008] Furthermore, the polyamic acid is prepared by polycondensing 10.0-15.0 parts of 4,4'-diaminodiphenyl ether, 8.0-12.0 parts of pyromellitic dianhydride and 10.0-15.0 parts of 3,3',4,4'-biphenyltetracarboxylic dianhydride in 80.0-120.0 parts of N,N-dimethylformamide at 20-25°C for 1.0-2.0h, and the solid content of the polyamic acid solution is 15.0-25.0%.

[0009] Furthermore, the hexagonal boron nitride nanosheets have an average lateral size of 0.5 to 5.0 μm, a thickness of 5 to 20 nm, and a surface grafting rate of 2.0 to 8.0% after modification with 3-aminopropyltriethoxysilane; and the porosity of the porous oriented structure is 30 to 60%.

[0010] Furthermore, the thermal conductivity of the heat-conducting insulating layer in the plane direction is 8.0-15.0 W / m·K, and the thermal conductivity in the thickness direction is 2.0-4.0 W / m·K.

[0011] The present invention adopts a preparation design of a composite of surface-modified boron nitride nanosheets with an oriented structure and a polyimide matrix, which is mainly used to enhance the anisotropic thermal conductivity of the thermally conductive insulating layer. The core of the design of the thermally conductive insulating layer of the present invention is to achieve the ordered arrangement of thermally conductive fillers and the high performance of the matrix material through the coordinated optimization of precise material selection, surface modification, structural control and curing process. The selection of hexagonal boron nitride nanosheets as thermally conductive fillers is of great significance. Its unique two-dimensional layered structure and excellent in-plane thermal conductivity lay the foundation for the construction of an efficient thermal conductive network, and the size control of the nanosheets ensures effective dispersion and orientation in the matrix. 3-Aminopropyltriethoxysilane plays a key role in the surface modification of boron nitride nanosheets. The silane coupling agent introduces amino functional groups on the surface of the nanosheets through chemical bonding, significantly improving the interface compatibility and bonding strength between boron nitride and the polyimide matrix, reducing the interfacial thermal resistance, and at the same time, the appropriate surface grafting rate ensures the modification effect without affecting the thermal conductivity of the nanosheets themselves. The use of a filtration process is a key technology for achieving ordered orientation of boron nitride nanosheets. By controlling the filtration process, the nanosheets are preferentially aligned along the planar direction under the action of flow shear forces, forming a porous oriented structure with a specific porosity. This ordered arrangement maximizes the anisotropic thermal conductivity of boron nitride. The polyamic acid precursor is designed using a ternary system of 4,4'-diaminodiphenyl ether, pyromellitic dianhydride, and 3,3',4,4'-biphenyltetracarboxylic dianhydride, undergoing a low-temperature polycondensation reaction in N,N-dimethylformamide solvent. This molecular design not only ensures the excellent insulation properties and thermal stability of the polyimide, but also provides good film-forming properties and compatibility with boron nitride nanosheets through the rational combination of rigid and flexible units in the molecular chain. The implementation of the impregnation process allows the polyamic acid solution to fully penetrate the porous oriented boron nitride structure, maintaining the ordered arrangement of the nanosheets while achieving uniform coating of the substrate, forming a continuous composite structure. The three-step temperature-increasing curing process demonstrates precise control over the conversion of polyamic acid to polyimide. The pre-drying stage removes most of the solvent and initiates the curing process. The subsequent step-by-step temperature increase ensures complete cyclization of the amic acid groups and thorough removal of the solvent, avoiding structural defects and stress concentration that could result from rapid temperature increases. This meticulously designed preparation process perfectly combines the highly oriented arrangement of boron nitride nanosheets with the excellent properties of the polyimide matrix, forming a composite material with significant anisotropic thermal conductivity. Its high in-plane thermal conductivity fully utilizes the intrinsic thermal conductivity of boron nitride, while its moderate through-thickness thermal conductivity maintains excellent insulation safety. The overall performance far exceeds the simple addition of individual materials.

[0012] Furthermore, the aluminum-based composite material of the heat dissipation layer and the heat sink is prepared by the following steps: A1. 100.0 parts of aluminum nitride particles having an average particle size of 0.5 to 5.0 μm, 2.0 to 5.0 parts of 10.0 to 50.0 μm titanium sponge powder, and 0.3 to 0.8 parts of stearic acid were ball-milled for 4.0 to 8.0 h to obtain titanium-coated aluminum nitride particles; A2. In situ nitridation of titanium occurs at 800~900 ° C, nitrogen 50~150mL / min for 1.0~3.0h to form a titanium nitride transition layer; A3. After 65.0~80.0 parts of 1060 series aluminum ingots were melted at 680~720 ° C, titanium nitride-coated aluminum nitride particles preheated at 180~220 ° C were added and stirred at 650~680 ° C, 300~500rpm for 5.0~10.0min, followed by die casting at an injection speed of 0.5~4.5m / s, an injection pressure of 50~90MPa, a boost pressure of 90~140MPa and holding pressure for 15~45s to obtain an integrated heat dissipation component; Furthermore, after die casting, the integrated heat dissipation component is naturally cooled to room temperature in air and annealed at 180-220°C for 3.0-5.0h, and then the heat sink surface is roughened by sandblasting at 0.3-0.6MPa for 2.0-5.0min.

[0013] Furthermore, the thickness of the titanium nitride transition layer is 25 to 85 nm, the interface between the titanium nitride transition layer and the aluminum nitride contains a coherent interface, and the interface between the titanium nitride and the metal aluminum substrate contains a semi-coherent interface.

[0014] Further, the silicone-based thermally conductive adhesive layer is selected from any one of Dow Corning TC-5026, TC-5022 or TC-5888; The heat sink has a height of 10-20 mm, a thickness of 1.0-1.8 mm, and a distance between adjacent heat sinks of 5.5-15 mm.

[0015] The present invention adopts a preparation design of titanium coating-in-situ nitriding-die casting integrated molding, which is mainly used to enhance the thermal conductivity and interface bonding performance of the heat dissipation component. The preparation process of the heat dissipation layer and the heat sink aluminum-based composite material of the present invention embodies the design concept of multiple technology collaboration, and realizes the excellent bonding between the reinforcing phase and the matrix and the maximization of the overall heat dissipation efficiency through precise interface engineering and molding technology. The selection of aluminum nitride particles as the thermal conductivity enhancing phase is based on its excellent thermal conductivity and good compatibility with the aluminum matrix, and the control of the particle size ensures uniform distribution in the matrix and effective thermal conductivity network construction. The design of the titanium coating process has important interface modification significance. Sponge titanium powder forms a uniform coating layer on the surface of aluminum nitride particles through ball milling. Stearic acid as a ball milling aid not only prevents particle agglomeration, but also promotes the uniform adhesion of titanium powder on the surface of aluminum nitride, creating an ideal precursor structure for the subsequent in-situ nitriding reaction. The in-situ nitriding process is a core innovation in the entire fabrication process. Under a high-temperature nitrogen atmosphere, titanium undergoes a nitriding reaction, generating an in-situ titanium nitride transition layer. This in-situ titanium nitride layer forms a coherent interface with the aluminum nitride substrate, effectively reducing interfacial thermal resistance and enhancing interfacial bonding strength. Furthermore, the titanium nitride layer significantly improves the wettability and compatibility of the aluminum nitride with the subsequent aluminum substrate. The die-casting process achieves densification of the composite through precise temperature and pressure control. Proper stirring during the mixing of the preheated titanium nitride-coated aluminum nitride particles with the molten aluminum ensures uniform dispersion of the reinforcing phase. The high-pressure and high-speed injection molding process ensures the density of the composite and the integrated formation of the heat dissipation layer and heat sink, eliminating the contact thermal resistance associated with traditional separate structures. The nanometer-scale thickness of the titanium nitride transition layer enables precise control of interface engineering. Its coherent interface with the aluminum nitride and semi-coherent interface with the aluminum substrate create a gradient interface characteristic. This interface design not only ensures good load transfer and heat conduction, but also effectively mitigates thermal stresses caused by differences in thermal expansion coefficients. Annealing in the post-processing eliminates residual stresses from the die-casting process and optimizes the microstructure, while sandblasting roughening the heat sink surface increases the surface area and improves heat dissipation. The use of a silicone-based thermally conductive adhesive layer solves the problem of matching thermal expansion coefficients between different material layers, ensuring the continuity of the heat conduction path through its excellent interfacial wettability and thermal conductivity. The geometric design of the heat sink maximizes the heat dissipation surface area and convective heat transfer through optimized height, thickness, and spacing configurations. The entire preparation process organically combines interface modification, in-situ reaction, integrated molding, and post-processing to achieve perfect synergy between the high thermal conductivity of aluminum nitride, the interface optimization effect of the titanium nitride transition layer, and the molding and processing performance of the aluminum substrate, forming an integrated heat dissipation component with excellent thermal conductivity and mechanical properties. Its overall performance significantly exceeds the individual contributions of each component material.

[0016] The present invention also discloses a method for preparing a PCB circuit board material with high heat dissipation performance, comprising the following steps: S1. Preparation of circuit board layer: forming a copper-clad FR-4 substrate and soldering a metal positioning stage on its surface; S2. Preparation and lamination of a thermally conductive insulating layer: Surface-modified boron nitride nanosheets are first filtered to form a porous oriented structure, then impregnated with a polyamic acid solution and hot-pressed to obtain a polyimide composite film with parallel orientation of hexagonal boron nitride nanosheets, which is then laminated to the back of the circuit board layer; S3. Preparation of heat dissipation assembly: forming a heat dissipation layer and heat sink through a coating-in-situ nitriding-die-casting process, followed by heat treatment and roughening of the heat sink surface; S4 overall assembly: a silicone-based thermally conductive adhesive layer is provided between the metal bottom layer and the heat dissipation component, and then the metal bottom layer, the silicone-based thermally conductive adhesive layer, the heat dissipation component and the circuit board obtained in step S2 - the thermally conductive insulating layer composite structure is pressed together as a whole by hot pressing to obtain the high heat dissipation performance PCB circuit board material; The hot pressing conditions in step S4 are as follows: temperature 150-180°C, pressure 2.0-5.0 MPa, and holding time 30-60 minutes; Furthermore, the specific process of step S2 includes: S2-1: Boron nitride nanosheets whose surfaces were modified with 3-aminopropyltriethoxysilane were dispersed in deionized water to form a suspension with a concentration of 0.5-3.0 mg / mL. After ultrasonic dispersion at 200-400 W for 30-60 min, the suspension was filtered through a polytetrafluoroethylene membrane with a pore size of 0.1-0.8 μm under reduced pressure of 0.01-0.05 MPa for 10-30 minutes to form a porous oriented membrane. S2-2: Immerse the porous boron nitride oriented film in a polyamic acid solution for 5 to 15 minutes at a temperature of 20 to 25° C. and a pressure of 0.02 to 0.08 MPa; S2-3: The impregnated composite material was pre-dried at 80-120°C, and then hot-pressed and cured at 140-145°C, 280-290°C, and 350-360°C in steps under a pressure of 1.0-3.0 MPa.

[0017] (3) Beneficial technical effects 1. The present invention achieves an efficient heat conduction path from the circuit board layer to the heat sink through a carefully constructed multi-layer composite structure. The orderly oriented arrangement of boron nitride nanosheets and the polyimide matrix synergistically construct a continuous thermal conductivity network while maintaining excellent insulation properties. The titanium nitride transition layer improves the interface bonding between aluminum nitride and the aluminum matrix, reducing interfacial thermal resistance. The silicone-based thermal conductive adhesive layer eliminates interlayer contact thermal resistance and ensures the continuity of the heat conduction path. The heat sink and heat dissipation layer are integrally die-cast to eliminate the contact thermal resistance of traditional separate structures. The materials of each functional layer are synergistically optimized through interface engineering to achieve efficient heat transfer along the optimized conduction path, achieving an overall heat dissipation effect far exceeding that of a single material. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a schematic diagram of the structure of the PCB circuit board material with high heat dissipation performance of the present invention.

[0019] Figure 2 This is a morphology diagram of the boron nitride nanosheets prepared in Example 1 of the present invention.

[0020] Figure 3 This is a fracture morphology diagram of the polyimide layered composite material prepared in Example 1 of the present invention.

[0021] Figure 4 This is a fracture morphology diagram of the polyimide layered composite material prepared in Example 3 of the present invention.

[0022] Figure 5 This is the interface between the aluminum nitride and titanium carbide transition layers prepared in Example 1 of the present invention.

[0023] Figure 6 This is the line scan element distribution between aluminum nitride / titanium nitride / aluminum in the aluminum nitride reinforced aluminum-based composite material prepared in Example 2 of the present invention.

[0024] Figure 7 This is a physical picture of the heat sink and heat dissipation layer prepared in Example 1 of the present invention.

[0025] In the figure: 1. Circuit board layer; 2. Thermal insulation layer; 3. Metal bottom layer; 4. Positioning platform; 5. Silicone-based thermal adhesive layer; 6. Heat dissipation layer; 7. Heat sink. DETAILED DESCRIPTION

[0026] To make the objectives, technical solutions and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0027] Example 1 A PCB circuit board material with high heat dissipation performance is characterized by comprising a circuit board layer 1, a heat-conducting insulating layer 2, a metal bottom layer 3, a silicone-based thermally conductive adhesive layer 5, a heat dissipation layer 6, and a heat sink 7 stacked sequentially from top to bottom, wherein: The circuit board layer 1 is a FR-4 glass fiber reinforced epoxy resin substrate with a copper coating thickness of 50 μm and a SAC305 lead-free tin-silver-copper alloy positioning platform 4 is set on its surface; The thermal insulation layer 2 is a 100 μm thick boron nitride composite filler polyimide layered composite material, wherein the hexagonal boron nitride nanosheets are arranged parallel to the plane of the thermal insulation layer 2, and the orientation degree of the hexagonal boron nitride nanosheets is 90%; The metal bottom layer 3 is T2 copper with a thickness of 2.0 mm; The heat dissipation layer 6 is an aluminum nitride reinforced aluminum matrix composite material and the surface of the aluminum nitride particles has a titanium nitride transition layer; The heat sink 7 and the heat dissipation layer 6 are integrally die-casted using the same aluminum-based composite material and are arranged on the lower surface of the heat dissipation layer 6 .

[0028] The thermally conductive insulating layer 2 of this embodiment is composed of 55.0 parts of boron nitride nanosheets whose surfaces are modified with 3-aminopropyltriethoxysilane. The porous oriented structure is first formed by filtration, then impregnated with polyamic acid and pre-dried at 100°C in a nitrogen atmosphere for 45 minutes. Then, the layers are cured in three steps at 142°C, 285°C, and 355°C.

[0029] The polyamic acid of this embodiment was prepared by polycondensing 12.5 parts of 4,4'-diaminodiphenyl ether, 10.0 parts of pyromellitic dianhydride, and 12.5 parts of 3,3',4,4'-biphenyltetracarboxylic dianhydride in 100.0 parts of N,N-dimethylformamide at 22°C for 1.5 hours. The solid content of the polyamic acid solution was 20.0%.

[0030] The average lateral size of the hexagonal boron nitride nanosheets of this embodiment is 2.5 μm, the thickness is 12 nm, and the surface grafting rate after modification with 3-aminopropyltriethoxysilane is 5.0%; the porosity of the porous oriented structure is 45%.

[0031] The thermal conductivity of the heat-conducting insulating layer 2 of this embodiment in the plane direction is 11.5 W / m·K, and the thermal conductivity in the thickness direction is 3.0 W / m·K.

[0032] The aluminum-based composite material of the heat dissipation layer 6 and the heat dissipation fin 7 of this embodiment is prepared by the following steps: A1. 100.0 parts of aluminum nitride particles having an average particle size of 2.5μm, 3.5 parts of 30.0μm titanium sponge powder and 0.55 parts of stearic acid were ball-milled for 6.0h to obtain titanium-coated aluminum nitride particles; A2 at 850 ° C, nitrogen 100mL / min under heat 2.0h titanium in situ nitridation to form a titanium nitride transition layer; A3 72.5 parts of 1060 series aluminum ingots were melted at 700 ° C and then preheated to 200 ° C titanium nitride-coated aluminum nitride particles were added and stirred at 665 ° C, 400rpm for 7.5min, followed by injection speed 2.5m / s, injection pressure 70MPa, boost pressure 115MPa die casting and holding pressure for 30s to obtain an integrated heat dissipation assembly; After die casting, the integrated heat dissipation assembly of this embodiment is naturally cooled to room temperature in air and annealed at 200°C for 4.0h. Then, the surface of the heat sink 7 is roughened by sandblasting at 0.45MPa for 3.5min.

[0033] The thickness of the titanium nitride transition layer in this embodiment is 55 nm. The interface between the titanium nitride transition layer and the aluminum nitride contains a coherent interface; the interface between the titanium nitride and the metal aluminum substrate contains a semi-coherent interface.

[0034] The silicone-based thermally conductive adhesive layer 5 of this embodiment is selected from Dow Corning TC-5026; The heat sink 7 of this embodiment has a height of 15 mm, a thickness of 1.4 mm, and a distance between adjacent heat sinks of 5.5 mm.

[0035] A method for preparing a PCB circuit board material with high heat dissipation performance in this embodiment includes the following steps: S1. Preparation of circuit board layer 1: forming a copper-clad FR-4 substrate and soldering a metal positioning stage 4 on its surface; S2. Preparation and lamination of thermally conductive insulating layer 2: Surface-modified boron nitride nanosheets are first filtered to form a porous oriented structure, then impregnated with a polyamic acid solution and hot-pressed to obtain a polyimide composite film with parallel orientation of hexagonal boron nitride nanosheets, which is then laminated to the back of the circuit board layer 1; S3 preparation of heat dissipation components: by coating - in situ nitriding - die casting process integrally formed heat dissipation layer 6 and heat sink 7, followed by heat treatment and roughening of the heat sink surface; S4 overall assembly: a silicone-based thermally conductive adhesive layer 5 is provided between the metal bottom layer 3 and the heat dissipation component, and then the metal bottom layer 3, the silicone-based thermally conductive adhesive layer 5, the heat dissipation component and the circuit board obtained in step S2 - the thermally conductive insulating layer composite structure is pressed together as a whole by hot pressing to obtain the high heat dissipation performance PCB circuit board material; The hot pressing conditions in step S4 of this embodiment are a temperature of 165°C, a pressure of 3.5 MPa, and a holding time of 45 minutes; The specific process of step S2 of this embodiment includes: S2-1: Boron nitride nanosheets modified with 3-aminopropyltriethoxysilane were dispersed in deionized water to form a suspension with a concentration of 1.75 mg / mL. After ultrasonic dispersion at 300 W for 45 min, the suspension was filtered through a polytetrafluoroethylene membrane with a pore size of 0.45 μm under a reduced pressure of 0.03 MPa for 20 minutes to form a porous oriented membrane. S2-2: Immerse the porous boron nitride alignment film in a polyamic acid solution for 10 minutes at a temperature of 22°C and a pressure of 0.05 MPa; S2-3: The impregnated composite material was pre-dried at 100°C and then hot-pressed and cured at 142°C, 285°C, and 355°C in steps under a pressure of 2.0 MPa.

[0036] Example 1 adopts a relatively conservative and balanced parameter configuration, reflecting the design concept of stability priority. This embodiment selects a medium specification of copper cladding thickness of 50μm, the thickness of the thermal insulation layer is 100μm at a moderate level, and the orientation degree of boron nitride nanosheets is 90% to ensure good thermal conductivity. At the same time, the average lateral size of the hexagonal boron nitride nanosheets is 2.5μm, the thickness is 12nm, and the surface grafting rate is 5.0% to form a relatively ideal filler dispersion state. In the preparation process of the heat dissipation component, the parameters such as the aluminum nitride particle size of 2.5μm, the amount of titanium powder of 3.5 parts, and the nitriding temperature of 850°C are all in the middle of the range. The die-casting process parameters such as the injection speed of 2.5m / s and the injection pressure of 70MPa also adopt medium intensity settings. The thermal conductivity of the thermally conductive insulation layer obtained in this embodiment is 11.5 W / m·K in the plane direction and 3.0 W / m·K in the thickness direction. The thickness of the titanium nitride transition layer is 55 nm. The heat sink specifications are 15 mm in height, 1.4 mm in thickness, and 5.5 mm in spacing. The overall parameter configuration focuses on the coordinated development of various performance properties and is suitable as a basic solution for standardized production.

[0037] Example 2 A PCB circuit board material with high heat dissipation performance is characterized by comprising a circuit board layer 1, a heat-conducting insulating layer 2, a metal bottom layer 3, a silicone-based thermally conductive adhesive layer 5, a heat dissipation layer 6, and a heat sink 7 stacked sequentially from top to bottom, wherein: The circuit board layer 1 is a FR-4 glass fiber reinforced epoxy resin substrate with a copper coating thickness of 35 μm and a SAC305 lead-free tin-silver-copper alloy positioning platform 4 is set on its surface; The thermally conductive insulating layer 2 is a 70 μm thick boron nitride composite filler polyimide layered composite material, wherein the hexagonal boron nitride nanosheets are arranged parallel to the plane of the thermally conductive insulating layer 2, and the orientation degree of the hexagonal boron nitride nanosheets is 95%; The metal bottom layer 3 is 6061 aluminum alloy with a thickness of 1.5 mm; The heat dissipation layer 6 is an aluminum nitride reinforced aluminum matrix composite material and the surface of the aluminum nitride particles has a titanium nitride transition layer; The heat sink 7 and the heat dissipation layer 6 are integrally die-casted using the same aluminum-based composite material and are arranged on the lower surface of the heat dissipation layer 6 .

[0038] The thermally conductive insulating layer 2 of this embodiment is composed of 65.0 parts of boron nitride nanosheets whose surfaces are modified with 3-aminopropyltriethoxysilane. A porous oriented structure is formed by filtration, and then impregnated with polyamic acid and pre-dried at 85°C in a nitrogen atmosphere for 50 minutes. Then, the layers are cured in three steps at 140°C, 285°C, and 360°C.

[0039] The polyamic acid of this embodiment was prepared by polycondensing 10.5 parts of 4,4'-diaminodiphenyl ether, 8.5 parts of pyromellitic dianhydride and 11.0 parts of 3,3',4,4'-biphenyltetracarboxylic dianhydride in 90.0 parts of N,N-dimethylformamide at 20°C for 1.2 h. The solid content of the polyamic acid solution was 17.5%.

[0040] The hexagonal boron nitride nanosheets of this embodiment have an average lateral size of 1.5 μm and a thickness of 8 nm. After modification with 3-aminopropyltriethoxysilane, the surface grafting rate is 3.5%. The porosity of the porous oriented structure is 35%.

[0041] The thermal conductivity of the heat-conducting insulating layer 2 of this embodiment in the plane direction is 13.5 W / m·K, and the thermal conductivity in the thickness direction is 2.5 W / m·K.

[0042] The aluminum-based composite material of the heat dissipation layer 6 and the heat dissipation fin 7 of this embodiment is prepared by the following steps: A1. 100.0 parts of aluminum nitride particles having an average particle size of 1.5 μm, 4.5 parts of 25.0 μm titanium sponge powder and 0.7 parts of stearic acid were ball-milled for 7.5 h to obtain titanium-coated aluminum nitride particles; A2 at 880 ° C, nitrogen 125mL / min under 1.5h to form a titanium nitride transition layer in situ nitridation of titanium; A3. 78.0 parts of 1060 series aluminum ingots were melted at 715 ° C and preheated to 210 ° C. Titanium nitride-coated aluminum nitride particles were added and stirred at 670 ° C and 450 rpm for 6.0 min, followed by die casting at an injection speed of 3.5 m / s, an injection pressure of 80 MPa, a boost pressure of 130 MPa, and holding pressure for 25 s to obtain an integrated heat dissipation assembly; After die casting, the integrated heat dissipation assembly of this embodiment is naturally cooled to room temperature in air and annealed at 190°C for 4.5 hours. Then, the surface of the heat sink 7 is roughened by sandblasting at 0.5 MPa for 3.0 minutes.

[0043] The thickness of the titanium nitride transition layer in this embodiment is 35 nm. The interface between the titanium nitride transition layer and the aluminum nitride contains a coherent interface; the interface between the titanium nitride and the metal aluminum substrate contains a semi-coherent interface.

[0044] The silicone-based thermally conductive adhesive layer 5 of this embodiment is selected from Dow Corning TC-5022; In this embodiment, the heat sink 7 has a height of 12 mm, a thickness of 1.2 mm, and a distance between adjacent heat sinks of 8 mm.

[0045] A method for preparing a PCB circuit board material with high heat dissipation performance in this embodiment includes the following steps: S1. Preparation of circuit board layer 1: forming a copper-clad FR-4 substrate and soldering a metal positioning stage 4 on its surface; S2. Preparation and lamination of thermally conductive insulating layer 2: Surface-modified boron nitride nanosheets are first filtered to form a porous oriented structure, then impregnated with a polyamic acid solution and hot-pressed to obtain a polyimide composite film with parallel orientation of hexagonal boron nitride nanosheets, which is then laminated to the back of the circuit board layer 1; S3 preparation of heat dissipation components: by coating - in situ nitriding - die casting process integrally formed heat dissipation layer 6 and heat sink 7, followed by heat treatment and roughening of the heat sink surface; S4 overall assembly: a silicone-based thermally conductive adhesive layer 5 is provided between the metal bottom layer 3 and the heat dissipation component, and then the metal bottom layer 3, the silicone-based thermally conductive adhesive layer 5, the heat dissipation component and the circuit board obtained in step S2 - the thermally conductive insulating layer composite structure is pressed together as a whole by hot pressing to obtain the high heat dissipation performance PCB circuit board material; The hot pressing conditions in step S4 of this embodiment are a temperature of 155°C, a pressure of 2.5 MPa, and a holding time of 35 minutes; The specific process of step S2 of this embodiment includes: S2-1: Boron nitride nanosheets modified with 3-aminopropyltriethoxysilane were dispersed in deionized water to form a suspension with a concentration of 2.5 mg / mL. After ultrasonic dispersion at 350 W for 35 min, the suspension was filtered through a polytetrafluoroethylene membrane with a pore size of 0.3 μm under a reduced pressure of 0.025 MPa for 15 minutes to form a porous oriented membrane. S2-2: Immerse the porous boron nitride alignment film in a polyamic acid solution for 8 minutes at a temperature of 20°C and a pressure of 0.04 MPa; S2-3: The impregnated composite material was pre-dried at 85°C and then hot-pressed and cured at 140°C, 285°C, and 360°C in steps under a pressure of 1.5 MPa.

[0046] Example 2 highlights the technical path for optimizing high thermal conductivity, and maximizes thermal conductivity efficiency through refined parameter control. This embodiment uses a thinner copper coating thickness of 35μm and a thermal insulation layer thickness of 70μm to reduce the length of the heat conduction path, while increasing the orientation degree of boron nitride nanosheets to 95%, and combining a high filler dosage of 65.0 parts and a smaller nanosheet size of 1.5μm and a thickness of 8nm to form a dense and orderly thermal conductive network. In the preparation of the heat dissipation component, finer aluminum nitride particles of 1.5μm were selected to increase the specific surface area, the amount of titanium powder was increased to 4.5 parts, and high-temperature nitriding at 880°C was used to strengthen the interface bonding. The die-casting process uses a high-pressure injection speed of 3.5m / s and a high-pressure injection pressure of 80MPa to ensure densification. This embodiment achieves an excellent planar thermal conductivity of 13.5 W / m·K. The thickness of the titanium nitride transition layer is controlled at a relatively thin level of 35nm. The heat sink adopts a compact design (height 12mm, thickness 1.2mm, spacing 8mm). The overall solution is specifically optimized for the extreme heat dissipation requirements of high-power density application scenarios.

[0047] Example 3 A PCB circuit board material with high heat dissipation performance is characterized by comprising a circuit board layer 1, a heat-conducting insulating layer 2, a metal bottom layer 3, a silicone-based thermally conductive adhesive layer 5, a heat dissipation layer 6, and a heat sink 7 stacked sequentially from top to bottom, wherein: The circuit board layer 1 is a FR-4 glass fiber reinforced epoxy resin substrate with a copper coating thickness of 65 μm and a SAC305 lead-free tin-silver-copper alloy positioning platform 4 is set on its surface; The thermal insulation layer 2 is a 160 μm thick boron nitride composite filler polyimide layered composite material, wherein the hexagonal boron nitride nanosheets are arranged parallel to the plane of the thermal insulation layer 2, and the orientation degree of the hexagonal boron nitride nanosheets is 87%; The metal bottom layer 3 is T2 copper with a thickness of 2.8 mm; The heat dissipation layer 6 is an aluminum nitride reinforced aluminum matrix composite material and the surface of the aluminum nitride particles has a titanium nitride transition layer; The heat sink 7 and the heat dissipation layer 6 are integrally die-casted using the same aluminum-based composite material and are arranged on the lower surface of the heat dissipation layer 6 .

[0048] The thermally conductive insulating layer 2 of this embodiment is composed of 45.0 parts of boron nitride nanosheets whose surfaces are modified with 3-aminopropyltriethoxysilane. A porous oriented structure is formed by filtration, and then impregnated with polyamic acid and pre-dried at 115°C for 35 minutes in a nitrogen atmosphere. Then, the layers are cured in three steps at 145°C, 290°C, and 350°C.

[0049] The polyamic acid of this embodiment was prepared by polycondensing 14.5 parts of 4,4'-diaminodiphenyl ether, 11.5 parts of pyromellitic dianhydride, and 14.0 parts of 3,3',4,4'-biphenyltetracarboxylic dianhydride in 115.0 parts of N,N-dimethylformamide at 24°C for 1.8 h. The solid content of the polyamic acid solution was 22.5%.

[0050] The hexagonal boron nitride nanosheets of this embodiment have an average lateral size of 4.0 μm and a thickness of 16 nm. After modification with 3-aminopropyltriethoxysilane, the surface grafting rate is 6.5%. The porosity of the porous oriented structure is 55%.

[0051] The thermal conductivity of the heat-conducting insulating layer 2 of this embodiment in the plane direction is 9.5 W / m·K, and the thermal conductivity in the thickness direction is 3.5 W / m·K.

[0052] The aluminum-based composite material of the heat dissipation layer 6 and the heat dissipation fin 7 of this embodiment is prepared by the following steps: A1. 100.0 parts of aluminum nitride particles having an average particle size of 4.0 μm, 2.5 parts of 40.0 μm titanium sponge powder and 0.4 parts of stearic acid were ball-milled for 5.0 h to obtain titanium-coated aluminum nitride particles; A2 at 820 ° C, nitrogen 75mL / min under heat 2.5h titanium in situ nitridation to form a titanium nitride transition layer; A3. 68.0 parts of 1060 series aluminum ingots were melted at 690 ° C and preheated to 185 ° C. Titanium nitride-coated aluminum nitride particles were added and stirred at 655 ° C, 350rpm for 8.5min, followed by die casting at an injection speed of 1.5m / s, an injection pressure of 60MPa, a boost pressure of 105MPa and holding pressure for 40s to obtain an integrated heat dissipation assembly; After die casting, the integrated heat dissipation assembly of this embodiment is naturally cooled to room temperature in air and annealed at 210°C for 3.5h. Then, the surface of the heat sink 7 is roughened by sandblasting at 0.35MPa for 4.5min.

[0053] The thickness of the titanium nitride transition layer in this embodiment is 75 nm. The interface between the titanium nitride transition layer and the aluminum nitride contains a coherent interface; the interface between the titanium nitride and the metal aluminum substrate contains a semi-coherent interface.

[0054] The silicone-based thermally conductive adhesive layer 5 of this embodiment is selected from Dow Corning TC-5888; The heat sink 7 of this embodiment has a height of 18 mm, a thickness of 1.6 mm, and a distance between adjacent heat sinks of 12 mm.

[0055] A method for preparing a PCB circuit board material with high heat dissipation performance in this embodiment includes the following steps: S1. Preparation of circuit board layer 1: forming a copper-clad FR-4 substrate and soldering a metal positioning stage 4 on its surface; S2. Preparation and lamination of thermally conductive insulating layer 2: Surface-modified boron nitride nanosheets are first filtered to form a porous oriented structure, then impregnated with a polyamic acid solution and hot-pressed to obtain a polyimide composite film with parallel orientation of hexagonal boron nitride nanosheets, which is then laminated to the back of the circuit board layer 1; S3 preparation of heat dissipation components: by coating - in situ nitriding - die casting process integrally formed heat dissipation layer 6 and heat sink 7, followed by heat treatment and roughening of the heat sink surface; S4 overall assembly: a silicone-based thermally conductive adhesive layer 5 is provided between the metal bottom layer 3 and the heat dissipation component, and then the metal bottom layer 3, the silicone-based thermally conductive adhesive layer 5, the heat dissipation component and the circuit board obtained in step S2 - the thermally conductive insulating layer composite structure is pressed together as a whole by hot pressing to obtain the high heat dissipation performance PCB circuit board material; The hot pressing conditions in step S4 of this embodiment are a temperature of 175°C, a pressure of 4.5 MPa, and a holding time of 55 minutes; The specific process of step S2 of this embodiment includes: S2-1: Boron nitride nanosheets modified with 3-aminopropyltriethoxysilane were dispersed in deionized water to form a suspension with a concentration of 1.0 mg / mL. After ultrasonic dispersion at 250 W for 55 min, the suspension was filtered through a polytetrafluoroethylene membrane with a pore size of 0.6 μm under a reduced pressure of 0.04 MPa for 25 minutes to form a porous oriented membrane. S2-2: Immerse the porous boron nitride alignment film in a polyamic acid solution for 13 minutes at a temperature of 24°C and a pressure of 0.06 MPa; S2-3: The impregnated composite material was pre-dried at 115°C and then hot-pressed and cured at 145°C, 290°C, and 350°C in steps under a pressure of 2.8 MPa.

[0056] Example 3 embodies the design concept of thick film and large-scale heat conduction channel, and improves the overall thermal conductivity by increasing the material thickness and optimizing the filler size distribution. This example uses a relatively thick copper cladding layer of 65μm and a thermal insulation layer of 160μm. Large-sized boron nitride nanosheets (4.0μm in lateral direction and 16nm in thickness) and a relatively low orientation degree of 87% are selected, and a high porosity of 55% is used to form a porous structure with good permeability. In the preparation of the heat dissipation component, large-sized aluminum nitride particles of 4.0μm and coarse titanium powder of 40.0μm are used. The amount of titanium powder is reduced to 2.5 parts and a lower nitriding temperature of 820°C is used. The die-casting process selects relatively mild parameters (injection speed of 1.5m / s and injection pressure of 60MPa) to adapt to the flow characteristics of large-particle fillers. The thermally conductive insulation layer formed in this embodiment has a planar thermal conductivity of 9.5 W / m·K and a thickness-direction thermal conductivity of 3.5 W / m·K. The thickness of the titanium nitride transition layer reaches 75 nm. The heat sink adopts a large-scale design (height 18 mm, thickness 1.6 mm, and spacing 12 mm). The overall solution is suitable for applications with high requirements for heat dissipation capacity and relatively loose space constraints.

[0057] Example 4 A PCB circuit board material with high heat dissipation performance is characterized by comprising a circuit board layer 1, a heat-conducting insulating layer 2, a metal bottom layer 3, a silicone-based thermally conductive adhesive layer 5, a heat dissipation layer 6, and a heat sink 7 stacked sequentially from top to bottom, wherein: The circuit board layer 1 is a FR-4 glass fiber reinforced epoxy resin substrate with a copper coating thickness of 42 μm and a SAC305 lead-free tin-silver-copper alloy positioning platform 4 is set on its surface; The thermal insulation layer 2 is a 135 μm thick boron nitride composite filler polyimide layered composite material, wherein the hexagonal boron nitride nanosheets are arranged parallel to the plane of the thermal insulation layer 2, and the orientation degree of the hexagonal boron nitride nanosheets is 92%; The metal bottom layer 3 is 6061 aluminum alloy with a thickness of 2.4 mm; The heat dissipation layer 6 is an aluminum nitride reinforced aluminum matrix composite material and the surface of the aluminum nitride particles has a titanium nitride transition layer; The heat sink 7 and the heat dissipation layer 6 are integrally die-casted using the same aluminum-based composite material and are arranged on the lower surface of the heat dissipation layer 6 .

[0058] The thermally conductive insulating layer 2 of this embodiment is composed of 52.0 parts of boron nitride nanosheets whose surfaces are modified with 3-aminopropyltriethoxysilane. A porous oriented structure is formed by filtration, and then impregnated with polyamic acid and pre-dried at 95°C in a nitrogen atmosphere for 40 minutes. Then, the layers are cured in three steps at 143°C, 288°C, and 358°C.

[0059] The polyamic acid of this embodiment was prepared by polycondensing 11.5 parts of 4,4'-diaminodiphenyl ether, 9.5 parts of pyromellitic dianhydride, and 13.0 parts of 3,3',4,4'-biphenyltetracarboxylic dianhydride in 105.0 parts of N,N-dimethylformamide at 23°C for 1.6 h. The solid content of the polyamic acid solution was 18.5%.

[0060] The hexagonal boron nitride nanosheets of this embodiment have an average lateral size of 3.2 μm and a thickness of 14 nm. After modification with 3-aminopropyltriethoxysilane, the surface grafting rate is 4.5%. The porosity of the porous oriented structure is 42%.

[0061] The thermal conductivity of the heat-conducting insulating layer 2 of this embodiment in the plane direction is 10.5 W / m·K, and the thermal conductivity in the thickness direction is 2.8 W / m·K.

[0062] The aluminum-based composite material of the heat dissipation layer 6 and the heat dissipation fin 7 of this embodiment is prepared by the following steps: A1. 100.0 parts of aluminum nitride particles having an average particle size of 3.2μm, 3.0 parts of 35.0μm titanium sponge powder and 0.6 parts of stearic acid were ball-milled for 6.5h to obtain titanium-coated aluminum nitride particles; A2 at 865 ° C, nitrogen 110mL / min under 1.8h to form a titanium nitride transition layer in situ nitridation of titanium; A3. 75.0 parts of 1060 series aluminum ingots were melted at 705 ° C and preheated to 195 ° C. Titanium nitride-coated aluminum nitride particles were added and stirred at 662 ° C, 425rpm for 7.0min, followed by die casting at an injection speed of 2.8m / s, an injection pressure of 75MPa, a boost pressure of 122MPa, and holding pressure for 32s to obtain an integrated heat dissipation assembly; After die casting, the integrated heat dissipation assembly of this embodiment is naturally cooled to room temperature in air and annealed at 195°C for 4.2 hours. Then, the surface of the heat sink 7 is roughened by sandblasting at 0.42 MPa for 3.8 minutes.

[0063] The thickness of the titanium nitride transition layer in this embodiment is 62 nm. The interface between the titanium nitride transition layer and the aluminum nitride contains a coherent interface; the interface between the titanium nitride and the metal aluminum substrate contains a semi-coherent interface.

[0064] The silicone-based thermally conductive adhesive layer 5 of this embodiment is selected from Dow Corning TC-5026; The heat sink 7 of this embodiment has a height of 16 mm, a thickness of 1.5 mm, and a distance between adjacent heat sinks of 11 mm.

[0065] A method for preparing a PCB circuit board material with high heat dissipation performance in this embodiment includes the following steps: S1. Preparation of circuit board layer 1: forming a copper-clad FR-4 substrate and soldering a metal positioning stage 4 on its surface; S2. Preparation and lamination of thermally conductive insulating layer 2: Surface-modified boron nitride nanosheets are first filtered to form a porous oriented structure, then impregnated with a polyamic acid solution and hot-pressed to obtain a polyimide composite film with parallel orientation of hexagonal boron nitride nanosheets, which is then laminated to the back of the circuit board layer 1; S3 preparation of heat dissipation components: by coating - in situ nitriding - die casting process integrally formed heat dissipation layer 6 and heat sink 7, followed by heat treatment and roughening of the heat sink surface; S4 overall assembly: a silicone-based thermally conductive adhesive layer 5 is provided between the metal bottom layer 3 and the heat dissipation component, and then the metal bottom layer 3, the silicone-based thermally conductive adhesive layer 5, the heat dissipation component and the circuit board obtained in step S2 - the thermally conductive insulating layer composite structure is pressed together as a whole by hot pressing to obtain the high heat dissipation performance PCB circuit board material; The hot pressing conditions in step S4 of this embodiment are a temperature of 168°C, a pressure of 3.8 MPa, and a holding time of 48 minutes; The specific process of step S2 of this embodiment includes: S2-1: Boron nitride nanosheets modified with 3-aminopropyltriethoxysilane were dispersed in deionized water to form a suspension with a concentration of 2.1 mg / mL. After ultrasonic dispersion at 320 W for 42 min, the suspension was filtered through a polytetrafluoroethylene membrane with a pore size of 0.52 μm under a reduced pressure of 0.035 MPa for 18 minutes to form a porous oriented membrane. S2-2: Immerse the porous boron nitride alignment film in a polyamic acid solution for 11 minutes at a temperature of 23°C and a pressure of 0.055 MPa; S2-3: The impregnated composite material was pre-dried at 95°C and then hot-pressed and cured at 143°C, 288°C, and 358°C in steps under a pressure of 2.4 MPa.

[0066] Example 4 demonstrates a comprehensive optimization strategy of refined regulation and performance balance, and achieves a synergistic improvement of multiple performance indicators through precise matching of parameters. This embodiment selects a copper coating thickness of 42μm and a thermal conductive insulation layer thickness of 135μm. The orientation degree of boron nitride nanosheets is 92%, which is at a high level. The nanosheet size is 3.2μm, the thickness is 14nm, and the surface grafting rate is 4.5%, forming a good filler-matrix interface bond. The heat dissipation component is prepared using 3.2μm aluminum nitride particles, 35.0μm titanium powder, and a moderate dosage of 3.0 parts. The nitriding temperature of 865°C ensures sufficient interfacial reaction. The die-casting process parameters (injection speed 2.8m / s, injection pressure 75MPa, and boost pressure 122MPa) are finely adjusted to obtain the optimal organizational structure. The thermal conductivity of the thermally conductive insulation layer obtained in this embodiment is 10.5 W / m·K in the plane and 2.8 W / m·K in the thickness direction. The thickness of the titanium nitride transition layer is 62 nm. The heat sink specifications (height 16 mm, thickness 1.5 mm, spacing 11 mm) achieve a good balance between heat dissipation efficiency and structural compactness. The overall solution embodies the systematic and scientific nature of parameter optimization and is suitable for complex application environments with high comprehensive performance requirements.

[0067] Comparative Example 1: Basically the same as Example 1, except that the hexagonal boron nitride nanosheets in the thermally conductive insulating layer are randomly distributed and not oriented. The boron nitride nanosheets are directly mixed and stirred with the polyamic acid solution for 30 minutes and then directly cast into a film, omitting the suction and orientation process step.

[0068] Comparative Example 2 is basically the same as Example 1, except that the surface of the boron nitride nanosheets is not modified with 3-aminopropyltriethoxysilane, and the unmodified boron nitride nanosheets are directly used to form a porous oriented structure through a filtration process.

[0069] Comparative Example 3 is basically the same as Example 1, except that the thermal conductive insulation layer uses aluminum oxide filler instead of boron nitride filler, and 60.0 parts of aluminum oxide particles with an average particle size of 2.0 μm are used, and other preparation process conditions remain unchanged.

[0070] Comparative Example 4: is basically the same as Example 1, except that no titanium nitride transition layer is provided on the surface of the aluminum nitride particles in the heat dissipation layer, and the aluminum nitride particles are directly mixed and stirred with the aluminum ingot at 680°C and then die-casted, omitting the titanium coating and in-situ nitriding process steps.

[0071] Comparative Example 5: is basically the same as Example 1, except that the polyamic acid curing process adopts a one-step heating method, and is directly cured at a temperature of 350°C for 4 hours, without a three-step heating and curing process.

[0072] Comparative Example 6: is basically the same as Example 1, except that the heat dissipation layer and the heat sink adopt a split structure, the heat dissipation layer and the heat sink are prepared separately and assembled by bonding with thermal conductive adhesive, and the one-piece die-casting process is not adopted.

[0073] Comparative Example 7: basically the same as Example 1, except that stearic acid is not added when preparing titanium-coated aluminum nitride particles by ball milling, and the aluminum nitride particles and sponge titanium powder are directly ball milled for 6 hours.

[0074] Comparative Example 8: is basically the same as Example 1, except that the in-situ nitridation process is carried out in an air atmosphere, the nitridation temperature is 850°C, the holding time is 2 hours, and no nitrogen protective atmosphere is used.

[0075] Comparative Example 9 is basically the same as Example 1, except that during the preparation of the thermally conductive insulating layer, the polyamic acid pre-drying temperature is 150°C, the pre-drying time is 20 minutes, and the pre-drying treatment is not performed in a nitrogen atmosphere.

[0076] Comparative Example 10: It is basically the same as Example 1, except that the heat dissipation component after die-casting is not annealed, and is directly subjected to sandblasting and roughening treatment after die-casting.

[0077] Performance testing: The test subjects were boron nitride composite filler and polyimide laminated composite thermal insulation layers. The purpose of the test was to evaluate the material's in-plane thermal conductivity and verify the influence of hexagonal boron nitride nanosheet orientation on thermal conductivity. The test principle was based on the transient planar heat source method. A ring-shaped sensor was placed on the sample surface, generating heat and measuring the temperature response. The heat conduction process was analyzed to calculate the in-plane thermal conductivity. The experimental method used a Hot Disk thermal constant analyzer. A thermal insulation layer sample with a thickness of 100-200μm was sandwiched between two sheets of the same material to form a symmetrical structure. A sensor probe with a diameter of 3.189mm was used, with a test power of 10-50mW and a test time of 10-40 seconds. Key parameters included a test temperature of 25±1°C, a relative humidity of 50±5%, a sample thickness measurement accuracy of ±1μm, and a contact pressure of 0.1±0.01MPa between the sensor and the sample. Each group of samples consisted of at least eight samples.

[0078] Through-thickness thermal conductivity test for thermally conductive insulation layers: The test targets boron nitride composite filler and polyimide laminated composite materials. The purpose of the test is to evaluate the material's through-thickness thermal conductivity and verify the degree of anisotropic thermal conductivity. The test principle utilizes a steady-state heat flow method, establishing a temperature gradient through the thickness of the sample and calculating the thermal conductivity by measuring thermal resistance. The experimental method utilizes a modified ASTM D5470 thermal resistance tester. A 25mm diameter circular thermally conductive insulation layer sample is sandwiched between polished copper gauge blocks. Both sides of the sample are polished to a surface roughness of less than 2μm. A temperature difference of 20±1°C is set, and the heat flow and temperature distribution are measured when thermal equilibrium is reached. This standard is based on ASTM D5470-2017, "Standard Test Method for Thermal Transfer Properties of Thin Thermally Conductive Solid Electrical Insulation Materials." Key parameters include a temperature difference of 20±1°C between the upper and lower plates, a contact pressure of 0.69±0.05 MPa, a test ambient temperature of 23±2°C, and a sample surface flatness of less than 2μm. Each test group must contain at least eight samples. Data processing: The thermal conductivity is calculated according to Fourier's law λ = q·L / (A·ΔT), while the influence of interfacial thermal resistance is deducted. The test results should be within the range of 2.0-4.0 W / m·K, and the data reliability is evaluated using a 95% confidence interval.

[0079] Electrical insulation performance test: The test object is a complete thermally conductive insulation layer material. The purpose of the test is to evaluate the electrical insulation performance of the material to ensure that it maintains good electrical safety while maintaining heat dissipation function. The test principle is based on the dielectric strength test. A gradually increasing voltage is applied to both sides of the sample until breakdown, and the breakdown voltage value is measured. The experimental method uses a withstand voltage tester to prepare a circular sample with a diameter of 50mm. The sample is placed in a ball-plate electrode system and tested in transformer oil. The voltage is increased uniformly at a rate of 500V / s until breakdown. The standard is based on ASTM D149-2020 "Standard Test Method for Dielectric Breakdown Voltage and Dielectric Strength of Solid Insulating Materials at Power Frequency". Key parameters include a voltage increase rate of 500±50V / s, an electrode diameter of 25mm, an electrode spacing equal to the sample thickness, a test temperature of 23±2°C, a relative humidity of 45-75%, and 10 points are tested for each group of samples. Data processing calculates the dielectric strength as the breakdown voltage divided by the sample thickness, in kV / mm. The result should be greater than 20kV / mm. After eliminating outliers, the average value and standard deviation are calculated with a reliability level of 95%.

[0080] Overall thermal resistance test: The test object is a complete multi-layer structure of high-heat dissipation performance PCB circuit board materials. The purpose of the test is to evaluate the thermal conduction efficiency of the overall heat dissipation system and verify the collaborative heat dissipation effect of the multiple layers. The test principle is based on the steady-state thermal resistance measurement method. A heat source with a known power is applied to the circuit board layer, and the temperature distribution of each layer is measured to calculate the total thermal resistance. The experimental method is to build a thermal resistance test platform, mount a heating plate with a power of 10-50W on the circuit board layer as a heat source, use a thermocouple or infrared thermal imager to measure the temperature of each layer, place the heat sink in a constant temperature environment, and record the temperature distribution after reaching thermal equilibrium. Key parameters include heating power stability of ±1%, temperature measurement accuracy of ±0.1°C, ambient temperature control of 25±1°C, wind speed less than 0.5m / s, test time of no less than 30 minutes to reach steady state, and each sample is tested 3 times. Data processing is used to calculate the total thermal resistance Rth = (Thot-Tcold) / P, where Thot is the heat source temperature, Tcold is the heat sink temperature, and P is the heating power. The thermal resistance should be less than 0.5 K / W, and the reproducibility error should not exceed 5%. At the same time, the temperature drop distribution of each layer is analyzed to evaluate the heat dissipation contribution.

[0081] Thermal Cycling Reliability Testing: The test subjects are complete high-heat dissipation PCB materials. The purpose of the test is to evaluate the material's reliability and service life under temperature cycling conditions and verify the thermal stability of the multi-layer structure. The test principle is based on accelerated aging testing, accelerating the material aging process through high and low temperature cycles to observe performance trends. The experimental method uses a thermal cycling chamber with a set temperature cycle range of -40°C to +125°C, a ramp rate of 5°C / min, and a hold time of 30 minutes at both high and low temperatures. 1000 cycles are performed, and samples are taken periodically to test changes in thermal conductivity and bond strength. The standard is based on IPC-TM-650-2.6.7. Key parameters include a temperature range of -40±2°C to +125±2°C, a ramp rate of 5±1°C / min, temperature uniformity of ±3°C, and a relative humidity of less than 85%. Samples are taken every 100 cycles, with a minimum of 30 samples. Data processing and analysis of the rate of change of thermal conductivity and bonding strength show that the performance retention rate should be greater than 90%. Weibull distribution analysis is also performed to predict the service life. When the reliability level is 95%, the service life should be greater than 20 years.

[0082] The performance of Examples 1-4 and Comparative Examples 1-10 is summarized in Table 1. As can be seen from the table, the random distribution of boron nitride nanosheets disrupts the continuous in-plane thermal conduction path, resulting in a tortuous heat conduction path, increased interface scattering, a significant decrease in in-plane thermal conductivity, and the disappearance of anisotropic characteristics. Unmodified boron nitride has poor interfacial compatibility with polyimide and lacks chemical bonding. This increases interfacial thermal resistance, leading to a decrease in thermal conductivity. Increased interfacial defects significantly reduce dielectric strength and thermal cycling reliability. Aluminum oxide has a much lower intrinsic thermal conductivity than boron nitride, resulting in a sharp decrease in the thermal conductivity of the composite material, but its excellent insulation properties improve dielectric strength. The lack of a titanium nitride transition layer increases the thermal resistance of the aluminum nitride / aluminum interface and reduces load transfer efficiency. Interfacial stress concentration during thermal cycling causes cracking and shedding, significantly reducing reliability. One-step curing with elevated temperatures results in excessively rapid solvent evaporation, incomplete cyclization, insufficient molecular chain orientation, and uneven crosslinking density, leading to a decrease in thermal conductivity. The internal stresses and defects generated by rapid curing severely affect dielectric strength and thermal stability. The bonding interface of the split structure introduces additional contact thermal resistance, defects in the adhesive layer increase thermal resistance, and thermal expansion mismatch produces stress concentration and interface separation during thermal cycling. The lack of stearic acid causes particle agglomeration and uneven coating, and the poor thickness and continuity of the titanium nitride transition layer affect the interface bonding quality. During nitriding in an air atmosphere, oxygen competes with titanium to form oxide impurities, which reduce the thermal conductivity and interface bonding strength of the transition layer and increase interface stress and defect density. High-temperature pre-drying causes partial degradation and premature solidification of polyamic acid, destroying the orderly arrangement of nanosheets. The internal stress generated by rapid desolvation affects density. The lack of annealing treatment makes it impossible to eliminate the residual stress of die casting, which causes microcracks to initiate and expand during thermal cycling, significantly affecting long-term stability.

[0083] Table 1 Performance summary of Examples 1 to 4 and Comparative Examples 1 to 10 Figure 1 The multi-layer composite structure design of the PCB circuit board material with high heat dissipation performance of the present invention is intuitively demonstrated. The functional layers are stacked in sequence according to the circuit board layer, thermal insulation layer, metal bottom layer, silicone-based thermal conductive adhesive layer, heat dissipation layer and heat sink, forming a complete heat conduction path, verifying the structural rationality of the technical solution. Figure 2 It shows that the boron nitride nanosheets prepared in Example 1 present a typical two-dimensional layered structure with uniform thickness and clear edges, which confirms the high quality of the raw materials and the effectiveness of the preparation process. Figure 3 The results show that the boron nitride nanosheets in the fracture of the polyimide layered composite material in Example 1 are highly ordered and parallel oriented. The sheets are continuously distributed along the plane direction to form an obvious anisotropic structure. The polyimide matrix evenly covers the surface of the nanosheets, and the interface is tightly bonded without obvious defects, which directly proves the successful implementation of the filtration orientation process and the effective effect of surface modification. Figure 4The fracture surface of the composite material of Example 3 shows that it has a looser porous structure, the boron nitride nanosheets are larger in size but relatively less oriented, and the porosity is significantly higher than that of Example 1, which explains the structural basis of the lower planar thermal conductivity but higher thickness direction thermal conductivity of Example 3. Figure 5 The nanometer-scale thickness and uniform coating morphology of the titanium nitride transition layer on the surface of aluminum nitride particles are clearly presented. The interface between the transition layer and the aluminum nitride matrix is ​​straight and continuous, showing good coherent interface characteristics, confirming that the in-situ nitridation process successfully prepared the expected interface structure. Figure 6 The line scanning element distribution diagram of Example 2 shows the gradient distribution of each element at the aluminum nitride / titanium nitride / aluminum three-phase interface. The thickness of the titanium nitride transition layer is about 55nm, which is consistent with the design value. The aluminum, nitrogen, and titanium elements show a smooth transition at the interface without obvious mutations, verifying the integrity of the titanium nitride transition layer and the good state of the interface bonding. Figure 7 The integrated molding effect of the heat sink and the heat dissipation layer prepared in Example 1 is demonstrated. The heat sinks are neatly arranged, the fin heights are uniform, and they are tightly combined with the heat dissipation layer without stratification. The surface is roughened by sandblasting to present a uniform rough texture, which proves the successful implementation of the die-casting integrated molding process and the effectiveness of the post-processing process. The above-mentioned microstructural characterization results are highly consistent with the performance test data, which fully verifies the scientific nature of the technical solution of the present invention and the reliability of the implementation effect.

[0084] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that any equivalent structural transformations made within the scope of the present invention using the contents of the present invention's description and drawings should be included within the scope of protection of the claims of the present invention.

Claims

1. A PCB circuit board material with high heat dissipation performance, characterized by: The invention comprises a circuit board layer (1), a heat-conducting insulating layer (2), a metal bottom layer (3), a silicone-based heat-conducting adhesive layer (5), a heat dissipation layer (6), and a heat sink (7) stacked in sequence from top to bottom, wherein: The circuit board layer (1) is a FR-4 glass fiber reinforced epoxy resin substrate with a copper coating thickness of 35 to 70 μm, and a SAC305 lead-free tin-silver-copper alloy positioning platform (4) is arranged on the surface of the substrate; The thermal conductive insulating layer (2) is a boron nitride composite filler polyimide layered composite material with a thickness of 50 to 200 μm, wherein the hexagonal boron nitride nanosheets are arranged parallel to the plane direction of the thermal conductive insulating layer (2), and the orientation degree of the hexagonal boron nitride nanosheets is 85 to 98%; The metal bottom layer (3) is T2 copper or 6061 aluminum alloy with a thickness of 1.0-3.0 mm; The heat dissipation layer (6) is an aluminum nitride reinforced aluminum-based composite material, and the surface of the aluminum nitride particles has a titanium nitride transition layer; The heat sink (7) and the heat dissipation layer (6) are integrally die-casted using the same aluminum-based composite material and are arranged on the lower surface of the heat dissipation layer (6).

2. A PCB circuit board material with high heat dissipation performance as claimed in claim 1, characterized in that: The thermally conductive insulating layer (2) is formed by filtering 40.0-70.0 parts of boron nitride nanosheets whose surfaces are modified with 3-aminopropyltriethoxysilane to form a porous oriented structure, then impregnating polyamic acid and pre-drying it at 80-120°C in a nitrogen atmosphere for 30-60 minutes, and then heating and curing it in three steps at 140-145°C, 280-290°C, and 350-360°C.

3. A PCB circuit board material with high heat dissipation performance as claimed in claim 2, wherein the polyamic acid is prepared by polycondensing 10.0 to 15.0 parts of 4,4'-diaminodiphenyl ether, 8.0 to 12.0 parts of pyromellitic dianhydride and 10.0 to 15.0 parts of 3,3',4,4'-biphenyltetracarboxylic dianhydride in 80.0 to 120.0 parts of N,N-dimethylformamide at 20 to 25°C for 1.0 to 2.0h, and the solid content of the polyamic acid solution is 15.0 to 25.0%.

4. A PCB circuit board material with high heat dissipation performance as claimed in claim 1, characterized in that: The hexagonal boron nitride nanosheets have an average lateral size of 0.5 to 5.0 μm and a thickness of 5 to 20 nm, and a surface grafting rate of 2.0 to 8.0% after modification with 3-aminopropyltriethoxysilane; the porosity of the porous oriented structure is 30 to 60%.

5. The PCB circuit board material with high heat dissipation performance according to claim 1, characterized in that: The thermal conductivity of the heat-conducting insulating layer (2) in the plane direction is 8.0-15.0 W / m·K, and the thermal conductivity in the thickness direction is 2.0-4.0 W / m·K.

6. A PCB circuit board material with high heat dissipation performance as claimed in claim 1, characterized in that: The aluminum-based composite material of the heat dissipation layer (6) and the heat dissipation fin (7) is prepared by the following steps: A1. 100.0 parts of aluminum nitride particles having an average particle size of 0.5 to 5.0 μm, 2.0 to 5.0 parts of 10.0 to 50.0 μm titanium sponge powder, and 0.3 to 0.8 parts of stearic acid were ball-milled for 4.0 to 8.0 h to obtain titanium-coated aluminum nitride particles; A2. In situ nitridation of titanium occurs at 800~900 ° C, nitrogen 50~150mL / min for 1.0~3.0h to form a titanium nitride transition layer; A3. After 65.0~80.0 parts of 1060 series aluminum ingots were melted at 680~720 ° C, titanium nitride-coated aluminum nitride particles preheated at 180~220 ° C were added and stirred at 650~680 ° C, 300~500rpm for 5.0~10.0min, followed by die casting at an injection speed of 0.5~4.5m / s, an injection pressure of 50~90MPa, a boost pressure of 90~140MPa and holding pressure for 15~45s to obtain an integrated heat dissipation component; After die casting, the integrated heat dissipation component is naturally cooled to room temperature in air and annealed at 180-220°C for 3.0-5.0h, and then the surface of the heat sink (7) is roughened by sandblasting at 0.3-0.6MPa for 2.0-5.0min.

7. A PCB circuit board material with high heat dissipation performance as claimed in claim 1, characterized in that: The thickness of the titanium nitride transition layer is 25-85 nm, the interface between the titanium nitride transition layer and the aluminum nitride contains a coherent interface, and the interface between the titanium nitride and the metal aluminum substrate contains a semi-coherent interface.

8. The PCB circuit board material with high heat dissipation performance according to claim 1, characterized in that: The silicone-based thermally conductive adhesive layer (5) is selected from any one of Dow Corning TC-5026, TC-5022 or TC-5888; The heat sink (7) has a height of 10-20 mm, a thickness of 1.0-1.8 mm, and a spacing between adjacent heat sinks of 5.5-15 mm.

9. The method for preparing a PCB circuit board material with high heat dissipation performance according to any one of claims 1 to 8, wherein: The following steps are involved: S1. Preparation of circuit board layer (1): forming a copper-clad FR-4 substrate and soldering a metal positioning stage (4) on its surface; S2. Preparation and lamination of a thermally conductive insulating layer (2): first, the surface-modified boron nitride nanosheets are filtered to form a porous oriented structure, then impregnated with a polyamic acid solution and hot-pressed to obtain a polyimide composite film with parallel orientation of hexagonal boron nitride nanosheets, which is then laminated to the back of the circuit board layer (1); S3. Preparation of heat dissipation components: forming a heat dissipation layer (6) and a heat sink (7) in one piece by a coating-in-situ nitriding-die casting process, and then heat treating and roughening the surface of the heat sink; S4. Overall assembly: a silicone-based thermally conductive adhesive layer (5) is provided between the metal bottom layer (3) and the heat dissipation component, and then the metal bottom layer (3), the silicone-based thermally conductive adhesive layer (5), the heat dissipation component and the circuit board-thermal insulating layer composite structure obtained in step S2 are pressed together as a whole by hot pressing to obtain the PCB circuit board material with high heat dissipation performance; The hot pressing conditions in step S4 are as follows: temperature 150-180°C, pressure 2.0-5.0 MPa, and holding time 30-60 minutes.

10. The method for preparing a PCB circuit board material with high heat dissipation performance according to claim 9, wherein: The specific process of step S2 includes: S2-1: Boron nitride nanosheets whose surfaces were modified with 3-aminopropyltriethoxysilane were dispersed in deionized water to form a suspension with a concentration of 0.5-3.0 mg / mL. After ultrasonic dispersion at 200-400 W for 30-60 min, the suspension was filtered through a polytetrafluoroethylene membrane with a pore size of 0.1-0.8 μm under reduced pressure of 0.01-0.05 MPa for 10-30 minutes to form a porous oriented membrane. S2-2: Immerse the porous boron nitride oriented film in a polyamic acid solution for 5 to 15 minutes at a temperature of 20 to 25° C. and a pressure of 0.02 to 0.08 MPa; S2-3: The impregnated composite material was pre-dried at 80-120°C, and then hot-pressed and cured at 140-145°C, 280-290°C, and 350-360°C in steps under a pressure of 1.0-3.0 MPa.

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