High-performance insulating heat-conducting film and preparation method thereof

Abstract

The invention discloses a high-performance insulating heat-conducting film and a preparation method thereof, and relates to the technical field of insulating heat-conducting films, the high-performance insulating heat-conducting film comprises a base material and slurry coated on the base material, the slurry is uniformly coated on the base material by a blade coating assembly, and bubbles in the slurry are removed in the coating process. The thermal conductivity of the ceramic particles can reach 1 W / mK to 30 W / mK, the metal oxide can improve the thermal conductivity of the slurry, ensure the electrical insulating property and optimize the processing characteristic and cost, and the metal oxide is an insulator, does not form a conductive path after being filled, ensures that the breakdown voltage of a film meets the insulation requirement of an electronic device, and has a good application prospect. The slurry prepared from the materials can greatly improve the heat-conducting property of a base material made of polyimide while ensuring the insulating property, and bubbles in the slurry can be removed as much as possible when the slurry is coated on the base material by the blade coating assembly, so that a slurry layer is prevented from being damaged in the subsequent drying and curing process.

Description

Technical Field

[0001] The present invention relates to the technical field of insulating thermally conductive films, in particular to a high-performance insulating thermally conductive film and a preparation method thereof. Background Art

[0002] As is well known, insulating thermally conductive film is a material that provides both insulation and thermal conductivity. Typically composed of polymers and thermally conductive particles, it exhibits excellent flexibility, elasticity, and adaptability. It can effectively dissipate heat by directing heat from a source to a heat sink, and is widely used in various electronic products.

[0003] For example, the invention patent with application publication number CN119795253A and application publication date April 11, 2025, entitled "A High Thermal Conductivity and High Insulation Polyimide Film Production Device", includes a support frame, a cutting mechanism is arranged between the upper and lower portions of the support frame, a tensioning assembly is fixedly arranged at one end of the top of the support frame, and a driving assembly is arranged at one end of the support frame. The cutting mechanism includes a fixed frame, a first motor, a bidirectional screw, a guide rod, a slitting knife, an adjustment hole, and an adjustment bolt. The fixed frame is arranged on two opposite sides of the support frame, the first motor is fixedly mounted on the fixed frame, the bidirectional screw is arranged between the support frames, and one end is matched with the output end of the first motor, the two ends of the guide rod are arranged between the fixed frames on both sides, the slitting knife is mounted on the bidirectional screw and the guide rod, the adjustment hole is opened on the support frame, and the adjustment bolt is installed inside the adjustment hole to determine the position of the fixed frame.

[0004] The shortcoming of the existing technology is that during the production of the insulating thermally conductive film, the thermally conductive filler needs to be made into a slurry, and then the slurry is evenly coated on the substrate through a coating process, and then heated in sections to make the slurry undergo two steps of pre-curing and curing, so that the slurry is fixed on the substrate. However, there will be bubbles in the slurry during the processing process. During the heating process of the slurry after coating, the bubbles in the slurry gradually expand due to heat, making the surface of the produced insulating thermally conductive film uneven, and even some bubbles broken, resulting in a thinner slurry layer in this part, which in turn affects the insulation performance of the insulating thermally conductive film. Summary of the Invention

[0005] The object of the present invention is to provide a high-performance insulating thermally conductive film and a preparation method thereof, so as to solve the above-mentioned deficiencies in the prior art.

[0006] In order to achieve the above object, the present invention provides the following technical solution: a high-performance insulating thermally conductive film, comprising a substrate and a slurry coated on the substrate, wherein: The substrate is made of polyimide; The slurry is a mixture of 50% to 60% ceramic particles, 5% to 7% metal oxides, and 33% to 45% binder by weight; The slurry is evenly coated on the substrate by the doctor blade assembly, and bubbles in the slurry are removed during the coating process.

[0007] A method for preparing a high-performance insulating and thermally conductive film, which is used to prepare the high-performance insulating and thermally conductive film in the above-mentioned solution, further comprising a processing table and a plurality of scraping assemblies mounted on the processing table, wherein the scraping assemblies each have a cutting knife provided at the bottom, and the heights of the plurality of scraping assemblies decrease along the moving direction of the substrate, and further comprising the following steps: S1. The substrate moves at a constant speed on the processing table, and multiple scraping assemblies scrape the slurry in a clumping state on the substrate in sequence to make the slurry evenly distributed; S2. Before the scraping assembly comes into contact with the slurry, the cutting blade on it cuts strip-shaped grooves on the slurry, and the workbench simultaneously heats the substrate at a low temperature; S3. Heat is transferred to the slurry through the substrate, causing the bubbles in the slurry to expand and be discharged from the active strip-shaped grooves on the upper surface of the slurry; S4, multiple scraping assemblies with decreasing heights scrape the slurry flat, and the slurry is pre-cured on the processing table; S5. The processed substrate is baked at 200° C. to solidify the slurry on the substrate.

[0008] As a further description of the above technical solution: the heating temperature of the surface of the processing platform is 40° C. to 80° C., and the heating temperature increases along the moving direction of the substrate.

[0009] As a further description of the above technical solution: the scraping assembly includes a >-shaped mounting plate, and the cutting knives are distributed in a linear array on the mounting plate.

[0010] As a further description of the above technical solution: a >-shaped material guiding strip and a >-shaped material pressing strip are sequentially arranged on the mounting plate along the moving direction of the substrate, and the bottom surface of the material guiding strip is higher than the bottom surface of the material pressing strip.

[0011] As a further description of the above technical solution: a slope is provided on the side wall of the pressing bar close to the cutting knife, and an inclined guide plate is provided at the bottom of the mounting plate and partially overlaps with the slope of the pressing bar.

[0012] As a further description of the above technical solution: the top of the guide plate is provided with guide strips that are distributed in parallel and point away from the middle of the processing table.

[0013] As a further description of the above technical solution: the cutting knife is provided with a dividing knife extending between the pressing strip and the guide plate.

[0014] As a further description of the above technical solution: the plurality of dividing knives correspond one to one with the plurality of guide strips.

[0015] As a further description of the above technical solution: a plurality of movable plates facing the guide bars are movably provided on the mounting plate, and the movable plates are coupled with the guide bars to cooperate with the material guide plates to form a semi-enclosed chamber.

[0016] In the above technical solution, the present invention provides a high-performance insulating thermally conductive film and a preparation method thereof, which have the following beneficial effects: ceramic particles can provide good insulating thermal conductivity, and their thermal conductivity can reach 1W / mK~30W / mK. Metal oxides can not only improve the thermal conductivity of the slurry, but also ensure electrical insulation, while optimizing processing characteristics and costs. The thermal conductivity of aluminum oxide is about 30W / mK, and the metal oxide itself is an insulator. After filling, no conductive path will be formed, ensuring that the breakdown voltage of the film meets the insulation requirements of electronic devices. The slurry composed of the above materials can greatly improve the thermal conductivity of the substrate made of polyimide while ensuring insulation performance, and the slurry is coated on the substrate by a scraping assembly, which can remove bubbles in the slurry as much as possible, thereby avoiding damage to the slurry layer during the subsequent drying and curing process. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments described in the present invention. For ordinary technicians in this field, other drawings can also be obtained based on these drawings.

[0018] Figure 1 A schematic diagram of the overall structure provided by an embodiment of the present invention; Figure 2 A schematic structural diagram of a scraping assembly provided in an embodiment of the present invention; Figure 3 for Figure 2 Enlarged view of point A in the middle; Figure 4 A schematic diagram of the bottom structure of a scraping assembly provided in an embodiment of the present invention; Figure 5 for Figure 4 Enlarged view of point B in the middle; Figure 6 A schematic diagram of the top structure of a material guide plate provided in an embodiment of the present invention; Figure 7 A schematic structural diagram of a guide bar provided in an embodiment of the present invention; Figure 8 for Figure 7 Enlarged view of point C in the middle; Figure 9 A schematic structural diagram of a movable plate provided in an embodiment of the present invention; Figure 10 for Figure 9 Enlarged view of point D in the middle; Figure 11 A schematic diagram of the bottom structure of the mounting plate provided in an embodiment of the present invention; Figure 12 for Figure 12 Enlarged view of point E in the middle; Figure 13 A schematic diagram of the internal structure of the mounting plate provided in an embodiment of the present invention.

[0019] Description of reference numerals: 1. Scraping assembly; 11. Mounting plate; 111. Cutting knife; 112. Dividing knife; 113. Exhaust hole; 12. Guide bar; 13. Guide plate; 131. Guide bar; 132. Movable plate; 133. Cam; 14. Pressing bar; 2. Substrate; 3. Processing table. DETAILED DESCRIPTION

[0020] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings.

[0021] Example 1 A high-performance insulating thermally conductive film comprises a substrate 2 and a slurry coated on the substrate 2, wherein: The substrate 2 is made of polyimide; The slurry is a mixture of 50% to 60% ceramic particles, 5% to 7% metal oxides, and 33% to 45% binder by weight; The slurry is evenly coated on the substrate 2 by the doctor blade assembly 1, and bubbles in the slurry are removed during the coating process.

[0022] Specifically, the slurry is composed of a thermally conductive filler and an adhesive. The thermally conductive filler is specifically composed of a mixture of ceramic particles accounting for 50% to 60% of the slurry mass and 5% to 7% of metal oxides. The ceramic particles are specifically one or more of aluminum oxide, boron nitride, and aluminum nitride. The metal oxide is specifically aluminum oxide. The adhesive is specifically epoxy resin or silicone resin.

[0023] Furthermore, ceramic particles can provide good insulation and thermal conductivity, and their thermal conductivity can reach 1W / mK~30W / mK. Metal oxides can not only improve the thermal conductivity of the slurry, but also ensure electrical insulation, while optimizing processing characteristics and costs. The thermal conductivity of aluminum oxide is about 30W / mK, and metal oxides themselves are insulators. After filling, no conductive path will be formed, ensuring that the breakdown voltage of the film meets the insulation requirements of electronic devices. The slurry composed of the above materials can greatly improve the thermal conductivity of the substrate 2 made of polyimide while ensuring insulation performance, and the scraping component 1 coats the slurry on the substrate 2, which can remove bubbles in the slurry as much as possible, thereby avoiding damage to the slurry layer during the subsequent drying and curing process.

[0024] Example 2 See also Figure 1-13 The embodiment of the present invention provides a technical solution: a method for preparing a high-performance insulating thermally conductive film, which is used to prepare the high-performance insulating thermally conductive film in Example 1, further comprising a processing table 3 and a plurality of scraping assemblies 1 mounted on the processing table 3, wherein the scraping assemblies 1 each include a cutting knife 111 provided at the bottom, and the height of the plurality of scraping assemblies 1 decreases along the moving direction of the substrate 2, and further comprising the following steps: S1, the substrate 2 moves at a constant speed on the processing table 3, and multiple scraping assemblies 1 scrape the slurry in a clumping state on the substrate 2 in sequence to make the slurry evenly distributed; S2. Before the scraping assembly 1 contacts the slurry, the cutting blade 111 thereon cuts strip-shaped grooves on the slurry, and the workbench simultaneously heats the substrate 2 at a low temperature; S3, heat is transferred to the slurry through the substrate 2, causing the bubbles in the slurry to expand and be discharged from the active strip-shaped grooves on the upper surface of the slurry; S4, multiple scraping assemblies 1 with decreasing heights scrape the slurry flat, and the slurry is pre-cured on the processing station 3; S5 , baking the processed substrate 2 at 200° C. to solidify the slurry on the substrate 2 .

[0025] Specifically, a plurality of groups of heating wires are arranged in sequence along the moving direction of the substrate 2 , and grooves adapted to the thickness of the substrate 2 are symmetrically opened inside the processing platform 3 .

[0026] Furthermore, when processing, the thermal conductive filler is first evenly dispersed in the adhesive, and high-speed stirring or ball milling can be used. Then, the substrate 2 is placed on the processing table 3, and both sides of the substrate 2 are stuck in the grooves on the processing table 3. Then, the slurry is dropped on the middle of the substrate 2, and the substrate 2 is moved on the processing table 3 (in a Figure 1 The moving direction of the substrate 2 is from right to left), the slurry contacts the scraping component 1, the scraping component 1 scrapes the slurry flat, and the heating wire in the processing table 3 heats the substrate 2 through the processing table 3, thereby heating the slurry. The slurry is initially solidified on the substrate 2, and the bubbles in the slurry expand and move upward. At this time, the cutting knife 111 plows a plurality of grooves on the slurry, so that the bubbles can be discharged not only from the top surface of the slurry, but also from the grooves of the slurry, shortening the bubble discharge path, thereby improving the bubble discharge rate. After the bubbles are discharged, the subsequent scraping component 1 continues to scrape the slurry, so that the slurry is evenly distributed on the substrate 2, and the height of the multiple scraping components 1 decreases along the moving direction of the substrate 2, which can gradually release the bubbles in the slurry while scraping the slurry thinner, so that the slurry is evenly distributed on the substrate 2, and the slurry close to the substrate 2 is pre-cured on the substrate 2. The treated substrate 2 enters the oven and the slurry is cured on the substrate 2 at 200°C.

[0027] In another embodiment provided by the present invention, the heating temperature of the surface of the processing station 3 is 40° C. to 80° C., and the heating temperature increases along the moving direction of the substrate 2 .

[0028] Specifically, the temperature of the substrate 2 is gradually increased by heating the processing station 3, so that more and thicker slurry is fixed on the substrate 2 during the movement of the substrate 2, and multiple scraping components 1 with decreasing heights gradually scrape more slurry, so that the thicker slurry layer is scraped off layer by layer, and the bubbles are gradually discharged. When the substrate 2 moves to the tail end of the processing station 3, the slurry on the substrate 2 is evenly scraped and pre-cured on the substrate 2 at 80°C.

[0029] In another embodiment provided by the present invention, the scraping assembly 1 includes a >-shaped mounting plate 11, the cutting knives 111 are distributed in a linear array on the mounting plate 11, and the mounting plate 11 is sequentially provided with a >-shaped guide strip 12 and a >-shaped pressing strip 14 along the moving direction of the substrate 2, and the bottom surface of the guide strip 12 is higher than the bottom surface of the pressing strip 14.

[0030] Specifically, the >-shaped mounting plate 11 can better form a >-shaped material guiding strip 12 and a material pressing strip 14 , and the cutting knife 111 is located between the material guiding strip 12 and the material pressing strip 14 .

[0031] Furthermore, during the movement of the substrate 2, the guide bar 12 first pushes the slurry, and the slurry is pushed to both sides of the substrate 2 by the guide bar 12 while moving with the substrate 2, thereby increasing the coverage area of ​​the slurry. After being scraped by the guide bar 12, the cutting knife 111 plows a plurality of grooves on the surface of the slurry. At the same time, the processing table 3 heats the substrate 2, and the bubbles in the slurry expand and are discharged, and a semi-enclosed space is formed between the mounting plate 11 and the processing table 3, in which the temperature is higher, which can allow the bubbles in the slurry to further expand and then be discharged. Then the pressing bar 14 further scrapes the slurry to flatten the grooves plowed by the cutting knife 111 on the surface of the slurry.

[0032] In another embodiment provided by the present invention, a slope is provided on the side wall of the pressing bar 14 close to the cutting knife 111 , and an inclined guide plate 13 is provided at the bottom of the mounting plate 11 and partially overlaps with the slope of the pressing bar 14 .

[0033] Specifically, during the movement of the substrate 2, the slope at the bottom of the pressing bar 14 can gather more slurry and further squeeze the slurry. When the slurry continues to enter, the slurry close to the slope at the bottom of the pressing bar 14 will roll upward under the guidance of the slope, and then pass through the gap between the pressing bar 14 and the guide plate 13 (such as Figure 3The pulp is moved into the flow channel between the guide plate 13 and the bottom of the mounting plate 11, and is guided by the guide plate 13 to move away from the middle of the processing table 3, further accelerating the efficiency of the pulp moving to the outside of the substrate 2 and accelerating the covering speed of the pulp on the substrate 2.

[0034] In another embodiment of the present application, the top of the guide plate 13 is provided with guide strips 131 distributed in parallel and directed away from the middle of the processing table 3, and the cutting knife 111 is provided with a plurality of distribution knives 112 extending between the pressing strip 14 and the guide plate 13, and the plurality of distribution knives 112 correspond to the plurality of guide strips 131 one by one.

[0035] Specifically, in the process of the pulp passing through the gap between the pressing strip 14 and the guide plate 13 into the flow channel between the guide plate 13 and the bottom of the mounting plate 11, the plurality of distribution knives 112 cut the pulp at multiple positions to release the air bubbles in the large pulp group, and the guide strips 131 are connected with the distribution knives 112, and the guide strips 131 can guide a small amount of pulp at the bottom layer to move away from the center of gravity of the processing table 3.

[0036] In another embodiment of the present application, the mounting plate 11 is movably provided with a plurality of movable plates 132 opposite to the guide strips 131, and the movable plates 132 are coupled with the guide strips 131 to form a semi-closed chamber with the guide plate 13.

[0037] Specifically, the bottom of the mounting plate 11 is provided with a plurality of air extraction holes 113 corresponding to the plurality of semi-closed chambers, and the air extraction holes 113 are connected with a vacuum pump, and the number of the movable plates 132 is three pairs and located in the middle of the mounting plate 11.

[0038] Further, in the process of work, the excess pulp is guided by the slope at the bottom of the pressing strip 14, passes through the gap between the pressing strip 14 and the guide plate 13 into the flow channel between the guide plate 13 and the bottom of the mounting plate 11, at this time, the movable plates 132 move downward, the bottom of the movable plates 132 is attached to the top of the guide strips 131, the flow channel formed by the mounting plate 11 and the guide plate is divided into semi-closed chambers, the opening of the chamber is the gap between the guide plate 13 and the opposite pressing strip 14, and the gap is in the middle of the mounting plate 11 and is closed by the pulp, at this time, the vacuum pump extracts the air in the chamber through the air extraction holes 113, and further releases the air bubbles in the pulp.

[0039] Furthermore, in the above embodiment, a spring can be provided between the mounting plate 11 and the movable plate 132, and a cam 133 for pushing the movable plate 132 downward is provided inside the mounting plate 11. During operation, the motor drives the cam 133 to rotate, and the cam 133 pushes the movable plate 132 downward. The movable plate 132 is coupled with the guide bar 131 and cooperates with the guide plate 13 to form a semi-closed chamber.

[0040] The above description is merely illustrative of certain exemplary embodiments of the present invention. It goes without saying that those skilled in the art will be able to modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the above drawings and description are illustrative in nature and should not be construed as limiting the scope of protection of the claims.

Claims

1. A high-performance insulating thermally conductive film, characterized in that: It comprises a substrate (2) and a slurry coated on the substrate (2), wherein: The substrate (2) is made of polyimide; The slurry is a mixture of 50% to 60% ceramic particles, 5% to 7% metal oxides, and 33% to 45% binder by weight; The slurry is evenly coated on the substrate (2) by the scraping assembly (1), and bubbles in the slurry are removed during the coating process.

2. A method for preparing a high-performance insulating thermally conductive film, which is used to prepare the high-performance insulating thermally conductive film according to claim 1, characterized in that: The method further comprises a processing table (3) and a plurality of scraping assemblies (1) mounted on the processing table (3), wherein the scraping assemblies (1) each have a cutting knife (111) provided at the bottom thereof, and the heights of the plurality of scraping assemblies (1) decrease along the moving direction of the substrate (2), and further comprises the following steps: S1, the substrate (2) moves at a constant speed on the processing table (3), and the plurality of scraping assemblies (1) scrape the slurry in a mass on the substrate (2) in sequence to make the slurry evenly distributed; S2, before the scraping assembly (1) comes into contact with the slurry, the cutting knife (111) thereon cuts strip-shaped grooves on the slurry, and the workbench simultaneously heats the substrate (2) at a low temperature; S3, heat is transferred to the slurry through the substrate (2), causing the bubbles in the slurry to expand and be discharged from the active strip-shaped grooves on the upper surface of the slurry; S4, multiple scraping assemblies (1) with decreasing heights scrape the slurry flat, and the slurry is pre-cured on the processing table (3); S5. The processed substrate (2) is baked at 200° C. to solidify the slurry on the substrate (2).

3. The method for preparing a high-performance insulating thermally conductive film according to claim 2, characterized in that: The heating temperature of the surface of the processing platform (3) is 40°C to 80°C, and the heating temperature increases along the moving direction of the substrate (2).

4. The method for preparing a high-performance insulating thermally conductive film according to claim 2, wherein: The scraping assembly (1) comprises a >-shaped mounting plate (11), and the cutting knives (111) are distributed in a linear array on the mounting plate (11).

5. The method for preparing a high-performance insulating thermally conductive film according to claim 4, characterized in that: A >-shaped material guide strip (12) and a >-shaped material pressing strip (14) are sequentially arranged on the mounting plate (11) along the moving direction of the substrate (2), and the bottom surface of the material guide strip (12) is higher than the bottom surface of the material pressing strip (14).

6. The method for preparing a high-performance insulating and thermally conductive film according to claim 5, characterized in that: A slope is provided on the side wall of the pressing strip (14) close to the cutting knife (111), and an inclined guide plate (13) is provided at the bottom of the mounting plate (11) and partially overlaps with the slope of the pressing strip (14).

7. The method for preparing a high-performance insulating and thermally conductive film according to claim 6, characterized in that: The top of the guide plate (13) is provided with guide strips (131) that are distributed in parallel and point away from the middle of the processing table (3).

8. The method for preparing a high-performance insulating and thermally conductive film according to claim 7, characterized in that: The cutting knife (111) is provided with a dividing knife (112) extending between the pressing strip (14) and the guide plate (13).

9. The method for preparing a high-performance insulating and thermally conductive film according to claim 8, characterized in that: The plurality of dividing knives (112) correspond one-to-one to the plurality of guide strips (131).

10. The method for preparing a high-performance insulating and thermally conductive film according to claim 7, characterized in that: A movable plate (132) facing the plurality of guide bars (131) is movably provided on the mounting plate (11); the movable plate (132) is coupled to the guide bars (131) to cooperate with the material guide plate (13) to form a semi-enclosed chamber.

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