Heat-conducting sheet edge covering processing technology and heat-conducting sheet thereof
By combining thin-film edge wrapping and vacuum coating processes, the problems of heat conduction and efficient production of thermal conductive sheets in narrow spaces have been solved, enabling the processing of thermal conductive sheets with ultra-narrow edges, improving production efficiency and reducing costs.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-01-16
- Publication Date
- 2026-04-14
AI Technical Summary
Existing heat-conducting sheet edge-wrapping processes are difficult to effectively conduct heat in narrow spaces, and traditional vacuum coating processes are inefficient and costly, failing to meet the high-efficiency, low-cost production needs of the consumer electronics industry.
By employing a process that combines thin-film edge wrapping and vacuum coating, ultra-narrow edge wrapping of 0.1~0.5mm is achieved through composite, punching and continuous roll-to-roll coating, ensuring that the heat-conducting sheet can effectively conduct heat in a narrow space, and achieving high-efficiency production through a single coating process.
This technology enables effective heat conduction of thermally conductive sheets in confined spaces, improving production efficiency, reducing production costs, and meeting the manufacturing needs of the consumer electronics industry.
Smart Images
Figure CN121848715A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of edge-wrapping technology for thermally conductive sheets, and particularly relates to an edge-wrapping process for thermally conductive sheets and the thermally conductive sheet itself. Background Technology
[0002] The edge banding with thermally conductive materials such as graphite sheets is mainly to prevent edge chipping and delamination, avoid the risk of short circuits caused by conductive dust, and improve edge insulation, environmental tolerance, and structural integrity. In applications with high reliability requirements such as consumer electronics, edge banding is not only a process specification, but also a necessary measure to ensure product safety and long-term stable operation.
[0003] There are various processes for edge banding of existing thermal conductive materials such as graphite sheets. The mainstream thin-film edge banding requires a minimum edge size of 1mm on each side. In the field of wearable devices, such as smart glasses, the minimum space in some areas of the temple is only 2mm. If the edge banding is 1mm on each side, the thermal conductive sheet cannot be extended, making it difficult to transfer the heat from the host to the end of the temple. Existing technology also includes vacuum coating process, with a coating thickness of at least 5μm for edge banding. This can significantly reduce the edge size and ensure the area of the thermal conductive sheet, allowing heat to pass smoothly through the extremely narrow area of the thermal conductive sheet. However, to ensure the integrity of the coating, two coating processes are usually required, which means that products can only be produced and delivered one by one, resulting in low mass production efficiency, inconvenience for customers, and high production costs. Summary of the Invention
[0004] The purpose of this invention is to provide a process for edge wrapping of thermally conductive sheets and a thermally conductive sheet thereof, in order to solve the technical problems in the prior art.
[0005] To achieve the above objectives, the present invention provides a process for edge wrapping of thermally conductive sheets, comprising the following steps: S1 combines the thermally conductive material roll with a shielding film to form a bottom shielding film layer covering the edge of the thermally conductive material, thus obtaining the first composite roll. S2 punches the first composite roll into the desired shape, penetrating the thermally conductive material while maintaining the integrity of the bottom shielding film layer, removes the waste of the thermally conductive material, forms multiple thermally conductive material monomers on the bottom shielding film layer, and transfers the punched first composite roll onto the first release film to obtain the second composite roll. S3 places the second composite roll from S2 into a vacuum coating machine. Under vacuum conditions, a coating layer is deposited on the exposed surface of the bottom shielding film layer and the exposed surface of the thermally conductive material monomer after punching. S4 involves punching through the second composite roll that has been coated in S3 at a distance of 0.1~0.5mm from the edge of the thermally conductive material unit to separate multiple thermally conductive sheets; S5 removes the first release film from the bottom of each thermally conductive sheet and transfers it to the second release film to achieve roll changing, thus obtaining the final thermally conductive sheet edge-wrapped roll.
[0006] Optionally, the process also includes step S6, which involves attaching the adhesive material to a predetermined location on each of the thermally conductive sheets.
[0007] Optionally, in step S4, the thermally conductive sheet includes the thermally conductive material monomer in the middle; the bottom of the thermally conductive material monomer is provided with the bottom shielding film layer, and the bottom shielding film layer and the thermally conductive material monomer are provided with the coating layer.
[0008] Optionally, the coating layer continuously covers the upper surface and sidewalls of the thermally conductive material monomer, and extends to cover the upper surface of the bottom shielding film layer that is not covered by the thermally conductive material monomer.
[0009] Optionally, the edge of the bottom shielding film layer extends beyond the edge of the thermally conductive material monomer by a length A, where the length of A ranges from 0.1 to 0.5 mm.
[0010] Optionally, the thickness of the coating layer is less than or equal to the length of A.
[0011] Optionally, the bottom shielding film layer is made of a high-temperature resistant film.
[0012] Optionally, in step S6, the adhesive material is bonded to the predetermined position of each of the thermally conductive sheets using high-precision optical alignment technology or precision hole fitting technology.
[0013] Optionally, the first release film and the second release film are transparent release films with high cleanliness and high flatness.
[0014] Optionally, a thermally conductive sheet is made using the thermally conductive sheet edge-wrapping process of any one of claims 1-9.
[0015] The above-mentioned technical solutions in the edge-wrapping process of a thermally conductive sheet provided by the embodiments of the present invention have at least one of the following technical effects: This process combines thin-film edge wrapping and vacuum coating to achieve an ultra-narrow edge of only 0.1~0.5mm, while avoiding the inefficiency of traditional multiple coating processes. It meets the need for thermally conductive sheets to extend and conduct heat in narrow spaces, and the use of roll coating significantly improves production efficiency and reduces production costs. Attached Figure Description
[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0017] Figure 1 This is a schematic diagram of the thermally conductive sheet structure of the present invention.
[0018] Figure 2 This is a schematic diagram of another embodiment of the thermally conductive sheet of the present invention.
[0019] Figure 3 This is a schematic diagram of another embodiment of the thermally conductive sheet of the present invention. The following are the labeling elements in the figure: 100. Thermally conductive material monomers; 200. Top shielding film layer; 300. Bottom shielding film layer; 400. Coating layer. Detailed Implementation
[0020] The present invention will be further described below with reference to embodiments, but the implementation of the present invention is not limited thereto.
[0021] Currently, the mainstream edge-wrapping process for thermally conductive materials such as graphite faces two major contradictions: 1. Its application in ultra-compact spaces is limited by the space encroachment of the film-based edge-wrapping process. This process typically uses a pre-formed frame or edge-wrapping film for physical wrapping, with a minimum edge width usually exceeding 1mm. In areas with extremely limited space, such as the temples of smart glasses, the width of the available heat conduction path may be only 2mm. If this process is used, the effective heat conduction width of the heat-conducting sheet will be severely reduced, or even reduced to zero, preventing heat from effectively extending to the far end and rendering the thermal management solution ineffective.
[0022] 2. Traditional vacuum coating processes are inefficient. They form a metal or ceramic (such as alumina) edging layer at the edge of the thermally conductive sheet using vapor deposition, with the edging thickness controllable to a minimum of 5μm, maximizing the effective heat-conducting area of the sheet. However, to ensure the integrity, density, and insulation reliability of the coating, multiple coating operations at different angles are typically required. This prevents continuous roll-to-roll production, requiring individual processing of each thermally conductive sheet. Consequently, production efficiency is extremely low, delivery cycles are long, and production costs are high, making it difficult to meet the large-scale, low-cost, and fast-paced manufacturing demands of the consumer electronics industry.
[0023] To address the above issues, we aim to find a process for edge-wrapping thermal conductive sheets that can achieve narrow edge banding to maximize the effective area of the thermally conductive sheet, while also being compatible with efficient and low-cost roll-to-roll continuous production. The process is as follows: Figure 1 As shown.
[0024] S1 composite Raw material preparation: A thermally conductive material roll and a bottom layer of masking film are laminated. The masking film is preferably a material that combines flexibility, high temperature resistance, and good adhesion to the coating material, such as PET, PI, copper foil, and aluminum foil, with polyimide (PI) film being the most preferred. The thermally conductive material can be graphite, boron nitride, or other composite thermally conductive materials, etc., as long as it can conduct heat and requires edge wrapping, it is within the scope of this invention.
[0025] In a clean environment, the thermally conductive material roll is placed on top of the shielding film and laminated using precision alignment rollers to form a first composite roll with a bottom shielding film layer. During lamination, it is essential to ensure that both edges of the thermally conductive material are completely and evenly covered by the upper and lower shielding films.
[0026] S2 Selective Punching This step is a crucial pretreatment step in this process, enabling the subsequent single-coating to complete the edge binding. The first composite roll is fed into a high-precision die-cutting machine, where a customized die is used for selective semi-cutting. The die shape matches the inner contour of the final required thermally conductive sheet, precisely controlling the cutting depth to completely cut through the full thickness of the thermally conductive material, but without cutting the bottom shielding film layer 300, thus ensuring the integrity of the bottom shielding film layer 300 as a continuous load-bearing substrate.
[0027] Next, waste is removed, and the waste area of the thermally conductive material is peeled off. At this point, multiple thermally conductive material monomers 100 are evenly arranged on the bottom shielding film layer 300, with the upper surface and sidewalls of the thermally conductive material monomers 100 fully exposed. They are then laminated onto the highly flat first release film to form the second composite roll. At this point, only one coating is needed to cover the entire edge to complete the wrapping of the upper surface and edge of the thermally conductive material monomers 100.
[0028] S3 Continuous Roll-to-Roll Vacuum Coating This step achieves full edge wrapping in a single film formation on a continuous strip. The second composite roll is then loaded into a roll-to-roll magnetron sputtering vacuum coating machine. The chamber is evacuated to a high vacuum (≤5.0×10⁻³ Pa) to ensure coating purity. Fluorocarbon compounds are used as the coating material. The coating provides excellent insulation and environmental protection.
[0029] Coating process: Due to the pretreatment in step S2, the entire upper surface of the thermally conductive material monomer 100 (covered by the bottom shielding film 200, but this film surface is to be coated), and the exposed sidewalls face the sputtering target. During continuous winding, the sputtered particle stream is uniformly deposited on the entire strip surface at a certain incident angle. Within the time of a single pass through the coating zone, a complete, continuous, and dense insulating coating layer 400 can be deposited simultaneously on the exposed upper surface and sidewalls of the thermally conductive material monomer 100, as well as the exposed surface of the bottom shielding film 300.
[0030] The edge of the bottom shielding film layer 300 is longer than the edge of the thermally conductive material monomer 100 by a length A, where A ranges from 0.1 to 0.5 mm. During coating, the coating layer 100 continuously covers the upper surface and sidewalls of the thermally conductive material monomer 100, and extends to cover the upper surface of the bottom shielding film layer 400 that is not covered by the thermally conductive material monomer 100. Furthermore, since the length of A ranges from 0.1 to 0.5 mm, and the thickness of the coating layer 400 is less than or equal to the length of A, the edge length is guaranteed to be within the range of 0.1 to 0.5 mm, and the sum of the two edge lengths is less than 1 mm. Compared to the existing 2 mm edge length, this increases the effective area of the thermally conductive sheet, allowing heat to extend to the far end. At this point, due to the protection of the bottom shielding film layer 300, the coating material is deposited on the upper surface and side cuts of the thermally conductive material monomer 100, forming a barrier together with the bottom shielding film layer 300, thus achieving a zero-edge process, which is more aesthetically pleasing and significantly reduces the possibility of product leakage.
[0031] S4 punched and separated thermal conductive sheet The second composite roll, now coated, is transferred to a precision cutting station. A separate high-precision die is used for full cutting. The distance between the cutting line and the edge of the individual thermally conductive material unit (100mm solid) is 0.1~0.5mm. After full cutting, individual thermally conductive sheets are obtained. (Example: ...) Figure 1 The thermally conductive sheet includes a central thermally conductive material monomer 100, a bottom shielding film layer 300, and a coating layer 400 that continuously covers the upper surface and sidewalls of the thermally conductive material monomer 100 and extends to cover the upper surface of the bottom shielding film layer 300 that is not covered by the thermally conductive material monomer 100.
[0032] S5 Re-roll Multiple thermally conductive sheets are peeled off from the first release film on which they are supported, and then reattached to the second release film using a high-precision transfer module to obtain the final finished roll of thermally conductive sheet edge-wrapped material.
[0033] S6 Adhesive Backing Depending on the application requirements, after S5, high-precision optical alignment technology or precision hole fitting technology can be used to precisely adhere the pre-cut thermally conductive adhesive to the bottom of each thermally conductive sheet. This adhesive can be used for bonding, and its soft polymer properties can further buffer edge stress and enhance reliability. Furthermore, the adhesive can be double-sided.
[0034] Specifically, this process combines thin-film edge wrapping and vacuum coating to achieve an ultra-narrow edge of only 0.1~0.5mm, while avoiding the inefficiency of traditional multiple coating processes. It meets the requirement that the heat-conducting sheet can extend to conduct heat in narrow spaces, and at the same time, the use of roll coating greatly improves production efficiency and reduces production costs.
[0035] like Figure 2 and 3 As shown, in another embodiment, the thermally conductive material roll and two layers of shielding film are combined. Compared with not having a top shielding film layer, having a top shielding film layer can prevent powder from falling off during punching, provide a certain degree of fixation, and facilitate better roll transfer, etc.
[0036] In a clean environment, the thermally conductive material roll is placed between two layers of shielding film and then laminated using precision alignment rollers to form a three-layer composite structure consisting of a top shielding film layer 200, the thermally conductive material, and a bottom shielding film layer 300, referred to as the first composite roll. During lamination, it is essential to ensure that both edges of the thermally conductive material are completely and evenly covered by the two layers of shielding film.
[0037] Selective punching is a crucial pretreatment step in this process, enabling the subsequent single-coating to complete the edge binding. The first composite roll is fed into a high-precision die-cutting machine, where a custom-made die is used for selective semi-punching. The die shape matches the inner contour of the final required thermally conductive sheet, precisely controlling the cutting depth to completely sever the top shielding film layer 200 and the entire thickness of the thermally conductive material, while leaving the bottom shielding film layer 300 uncut, thus ensuring the integrity of the bottom shielding film layer 300 as a continuous load-bearing substrate.
[0038] Next, waste removal is performed, peeling off and removing the waste areas of the top shielding film layer 200 and the thermally conductive material. At this point, the thermally conductive material monomers 100 are evenly arranged on the bottom shielding film layer 300, with their sidewalls completely exposed, while their upper surfaces are still covered by the remaining top shielding film layer 200. This is then laminated onto the high-flatness first release film to form the second composite roll. At this point, only one coating is needed to cover the entire edge to complete the wrapping of the thermally conductive material edge.
[0039] Continuous roll-to-roll vacuum coating process: Due to the pretreatment in step S2, the entire upper surface of the thermally conductive material monomer 100 (covered by the top shielding film layer 200, but this film surface is to be coated) and the exposed sidewalls face the sputtering target. During continuous roll-to-roll travel, the sputtered particle stream is uniformly deposited on the entire strip surface at a certain incident angle. Within the time of a single pass through the coating zone, a complete, continuous, and dense insulating coating layer 400 can be simultaneously deposited on the exposed thermally conductive material sidewalls and the surface of the top shielding film layer 200.
[0040] The thermally conductive sheets are separated by punching, and the coated second composite roll is transferred to a precision cutting station. A separate high-precision die is used for full cutting. The distance between the cutting line and the edge of the individual thermally conductive material unit is 0.1~0.5mm. After full cutting, individual thermally conductive sheets are obtained.
[0041] In another embodiment, the thermally conductive material monomer 100 may be irregularly shaped, and the coating layer 400 has a continuous covering of the upper surface and sidewalls of the thermally conductive material monomer 100 and extends to the upper surface of the bottom shielding film layer 300 extension edge.
[0042] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.
Claims
1. A process for edge-wrapping thermally conductive sheets, characterized in that, Includes the following steps: S1 combines the thermally conductive material roll with a shielding film to form a bottom shielding film layer covering the edge of the thermally conductive material, thus obtaining the first composite roll. S2 punches the first composite roll into the desired shape, penetrating the thermally conductive material while maintaining the integrity of the bottom shielding film layer, removes the waste of the thermally conductive material, forms multiple thermally conductive material monomers on the bottom shielding film layer, and transfers the punched first composite roll onto the first release film to obtain the second composite roll. S3 places the second composite roll from S2 into a vacuum coating machine. Under vacuum conditions, a coating layer is deposited on the exposed surface of the bottom shielding film layer and the exposed surface of the thermally conductive material monomer after punching. S4 involves punching through the second composite roll that has been coated in S3 at a distance of 0.1~0.5mm from the edge of the thermally conductive material unit to separate multiple thermally conductive sheets; S5 removes the first release film from the bottom of each thermally conductive sheet and transfers it to the second release film to achieve roll changing, thus obtaining the final thermally conductive sheet edge-wrapped roll.
2. The edge-wrapping process for thermally conductive sheets according to claim 1, characterized in that, It also includes step S6, which involves attaching the adhesive material to a predetermined position on each of the thermally conductive sheets.
3. The edge-wrapping process for thermally conductive sheets according to claim 1, characterized in that, In step S4, the thermally conductive sheet includes the thermally conductive material monomer in the middle; the bottom of the thermally conductive material monomer is provided with the bottom shielding film layer, and the bottom shielding film layer and the thermally conductive material monomer are provided with the coating layer.
4. The edge-wrapping process for thermally conductive sheets according to claim 3, characterized in that, The coating layer continuously covers the upper surface and sidewalls of the thermally conductive material monomer, and extends to cover the upper surface of the bottom shielding film layer that is not covered by the thermally conductive material monomer.
5. The edge-wrapping process for thermally conductive sheets according to claim 3, characterized in that, The edge of the bottom shielding film extends beyond the edge of the thermally conductive material monomer by a length A, where the length of A ranges from 0.1 to 0.5 mm.
6. The edge-wrapping process for the thermally conductive sheet according to claim 5, characterized in that, The thickness of the coating layer is less than or equal to the length of A.
7. The edge-wrapping process for thermally conductive sheets according to claim 1, characterized in that, The bottom shielding film is made of a high-temperature resistant film.
8. The edge-wrapping process for thermally conductive sheets according to claim 2, characterized in that, In step S6, the adhesive material is bonded to the predetermined position of each thermally conductive sheet using high-precision optical alignment technology or precision hole fitting technology.
9. The edge-wrapping process for thermally conductive sheets according to claim 1, characterized in that, The first release film and the second release film are transparent release films with high cleanliness and high flatness.
10. A thermally conductive sheet, characterized in that, It is manufactured using the edge-wrapping process of the thermally conductive sheet as described in any one of claims 1-9.