Pre-spreading tool for heat-conducting paste

Abstract

The utility model provides a pre-spreading tool for heat-conducting paste, which comprises a working part which is provided with a working surface with a cylindrical smooth outer surface and can form repeated rolling to simply, quickly, continuously and stably spread the heat-conducting paste and adjust a dispersed phase structure of the heat-conducting paste; the handheld part is used for braking the pre-spreading tool in a handheld manner; and the connecting part is used for forming movable connection between the working part and the handheld part. By implementing the embodiment of the invention, the requirements on a smearing tool and use skills thereof can be reduced, and pressure and shearing force can be sufficiently, continuously and continuously acted on the pre-spreading layer simply and quickly; the pre-spreading layer with high uniformity, smoothness, compactness, adhesion degree, cohesive force, rebound resilience, high heat-conducting property, low run-in period, high durability and improved pit pumping capacity is obtained, the simple and limit pursuit of a user for high-quality coating is met, the defect that heat-conducting paste picks up radiator assembly is overcome, and high robustness of a coating tool for heat-conducting paste pavement is achieved.

Description

Technical Field

[0001] This application relates to the technical field of thermal paste application, and particularly relates to a pre-spreading tool for thermal paste. Background Art

[0002] In recent years, electronic devices are developing towards miniaturization and high-density integration, and the thermal management problem of electronic devices has become increasingly prominent. According to research, for every 2°C increase in the operating temperature of an electronic device, its reliability will decrease by 10%. An efficient heat dissipation solution has become increasingly important. The main obstacle to heat flow from a heat source such as a chip to a radiator is the interfacial thermal resistance (ITR) at the contact surface between the two. However, the actual contact surface is the mutual contact of solid surfaces. Even after the solid surfaces are planarized, there are still a large number of micro-pit arrays at the micron and / or nanometer levels. This means that there are microscopic uneven voids in the contact surface. Each micro-pit is a small air cavity, and the actual contact area is as low as only 1% to 2%, and the rest is occupied by air. The thermal conductivity of air is extremely low, only 0.026 W / (m·K), which is a poor thermal conductor. When heat conduction passes through the contact interface, it will be affected by the interface thermal resistance. At this time, adding a suitable thermal conductive material to the gap can expel the air and form a tightly connected heat conduction path.

[0003] Thermal interface materials (TIMs) are thermal conductive materials widely used in contact interfaces, filled between the contact surfaces of the heat source surface and the assembled pressure-fastened radiator, so as to greatly reduce the interface thermal resistance, thereby giving full play to the heat dissipation effect of the radiator and improving the operating efficiency of the device. Thermal interface materials are one of the keys to electronic packaging heat dissipation management.

[0004] Thermal paste (or heat dissipation paste) is a filling type thermal interface material with good thermal conductivity. Its material is in paste or liquid form, with a certain viscosity and fluidity, and there is no obvious granularity on the surface. The common type of thermal paste is prepared by filling thermal conductive fillers in a polymer matrix, and its thermal conductivity is often determined by the thermal conductive fillers. The inherent thermal conductivity of the polymer matrix is relatively low (about 0.2 W / (m·K)), such as silicone oxygen alkane; thermal conductive fillers, such as metal powders or metal oxide powders such as alumina, and also such as boron nitride, silicon carbide, etc. can also be used to improve the overall physical properties. Currently, silicone-based thermal paste (i.e., thermal grease) is the main type on the market (about 84%). The mass fraction of the thermal conductive filler is generally 70–80%. Generally, the larger the particles of the thermal conductive filler, the less likely they are to form close packing between the fillers, which is not conducive to the formation of a thermal conduction path. Therefore, a method of filling with a combination of large and small particles is generally adopted now. And when the filling amount of the thermal conductive filler is insufficient, the fillers are dispersed in the matrix and exist in an isolated state from each other, and a continuous thermal conduction path cannot be formed. However, a high filling amount will lead to an increase in cost, an increase in mass, and a decrease in mechanical properties. The addition of small particle size fillers can also fill the gaps between the thermal conductive fillers, which can not only reduce the thermal resistance of the thermal paste, but also reduce the oil creeping tendency of silicone oxygen alkane or silicone oil, etc., making the oil leakage rate of the thermal paste lower. In addition, the existing product types of thermal paste include thermal grease, liquid metal, etc. Among them, thermal grease can be divided into phase change thermal grease (PhaseChange Thermal Interface Material, PCTIM) and non-phase change thermal grease (i.e., ordinary thermal grease, ThermalPaste) according to whether there is a phase change material. The phase change material is in a solid state at normal temperature and changes from a solid state to a liquid state when heated to the phase change temperature range (generally 45℃~65℃). Thermal paste such as thermal grease can also be divided into diluted type and viscous type according to the solvent ratio. In comparison, the differences between the two include that the diluted type has a higher solvent content, is easy to flow out during work, has a weaker shear resistance, better wettability, faster attenuation and lower durability, while the viscous type has less solvent, stronger shear resistance, poorer wettability, slower attenuation, higher durability and stronger thermal conductivity.

[0005] The ideal gap filling of thermal interface materials such as thermal grease is the core of effective heat transfer and ensuring the stable operation of electronic devices such as chips. However, thermal grease is easily restricted by the assembly of heat sources and heat sinks, and the overall interface thermal resistance is also related to the contact thermal resistance on the upper and lower surfaces of the thermal grease filling layer. That is to say, the interface thermal resistance from the heat source to the heat sink actually consists of three parts, including the contact thermal resistance from the heat source surface to the lower surface of the thermal grease filling layer, the thermal resistance existing in the thermal grease filling layer itself, and the contact thermal resistance from the upper surface of the thermal grease filling layer to the surface of the heat sink base. Therefore, choosing a suitable thermal grease to fill the air gap between interfaces can effectively reduce the contact thermal resistance between different structures and achieve rapid heat transfer of the chip. The adhesive layer thickness of thermal grease is a measure of the degree of separation between two contact surfaces. Since the thermal conductivity of thermal grease is usually low, the smaller the adhesive layer thickness of thermal grease, the smaller its thermal resistance. In theory, thermal grease only fills the interface voids, but an overly thin actual adhesive layer will also cause gaps, which are reliability problems caused by uneven application of thermal grease and mismatched thermal expansion coefficients during high and low temperature cycling. When the adhesive layer thickness is too thin, the minute unevenness on the solid surface cannot be fully filled, and the contact thermal resistance plays a dominant role in the total thermal resistance; but when the adhesive layer is thicker, the thermal resistance of the thermal grease itself becomes the key parameter. Currently, low thermal resistance, high durability, and resilience performance have become the difficulties in the development of thermal interface material technology. This high resilience ensures the stability and reliability of thermal grease during long-term use. However, how to achieve high resilience and mechanical compatibility of the material while meeting stringent thermal requirements remains the key to technological breakthroughs in the industry.

[0006] One of the important problems faced by thermal grease during use is the pump-out effect. The high and low temperature cycling of electronic devices is the cause of the pump-out (i.e., being extruded from the contact surface) effect of thermal grease such as thermal conductive silicone grease. Especially when sandwiched between a chip and a heat sink, it is very difficult to apply thermal grease without any bubbles, and the thermal grease remains in a liquid or paste state without curing. Thus, when the electronic device has temperature cycling (the temperature rises from low to high and then from high to low, such as in a PC) along with switching on and off, the package will undergo mechanical deformation, causing the thermal grease to spread outward and eventually overflow from between the interfaces. Moreover, thermal expansion and contraction will cause repeated volume changes of the bubbles in the thermal grease, strengthening the local overflow and phase separation phenomena and extruding the thermal conductive silicone grease out of the gap.

[0007] During the electronic thermal management packaging and usage process, thermal grease not only needs to function as eliminating contact thermal resistance but also needs to consider the deviation matching problem of different structures during the assembly process. This structural deviation requires materials with a certain degree of compressibility to make up for it to improve the assembly adaptability and reliability of electronic thermal management packaging. Thermal grease with a certain degree of flexibility and elasticity is an ideal material with the above characteristics within the package. Therefore, the flexibility and resilience of thermal grease are also one of the key issues to be considered during electronic thermal management packaging.

[0008] The application technique of thermal paste is another key to achieving ideal gap filling of thermal paste. The application technique is crucial for ensuring that the thermal paste can evenly fill the unevenness of the solid surface. The main concerns of existing application techniques are to be uniform, bubble-free, impurity-free, and as thin as possible while ensuring sufficient filling.

[0009] In current electronic thermal management packaging, the common application methods of thermal paste such as thermal grease:

[0010] (1) On the one hand, users can adopt methods such as dot application, linear application, X-shaped application, five-point application, nine-point application, etc. To squeeze an appropriate amount of thermal paste on the surface of the heat source, and then directly use the radiator to buckle and tighten the screws to apply pressure, so that the thermal paste is pressured to flow, so as to be expected to fill the contact surface gap.

[0011] However, for these application methods, ① none of them pre-spread, so it is difficult to estimate the appropriate amount. If too little is extruded, there will be no thermal paste filling in some parts after buckling; if too much is extruded, it will cause escape pollution and waste after buckling; ② The uneven structure of the solid surface such as the heat source generates many microscopic voids and unevenness. These voids are likely to trap air to form micro-bubbles when applying thermal paste. Therefore, when the application is uneven or the buckling pressure is insufficient, air may be trapped between the adhesive layer and the solid surface to form closed bubbles; in addition, for the five-point method or nine-point method, etc., the multi-point thermal paste flows in opposite directions after being pressured and is also likely to block air to form closed bubbles; in addition, since the buckling and pressurization are completed in a short period of time, it is more difficult to ensure that no micro-bubbles are enclosed during the process of the thermal paste being pressured to flow and fill the contact surface gap. These micro-bubbles lead to an increase in thermal resistance and poor contact; ③ It is more dependent on the buckling and pressurization performance, especially for fasteners with relatively thin thickness and weak overall stiffness performance, such as the fasteners used in laptops, which shows what is commonly called "relying on the fastener performance" in the DIY field of thermal paste.

[0012] (2) On the other hand, users can also squeeze an appropriate amount of thermal paste on the surface of the heat source as described above, and pre-spread it before buckling. For example, common application tools include plastic scrapers (or scrapers), silicone rubber finger cots, cotton swabs, etc. Among them, the plastic scraper is considered the most commonly used application tool and has high efficiency in applying some thermal paste; silicone rubber finger cots and cotton swabs have certain unique effects on thermal paste with special application difficulties. Using these application tools is beneficial to overcome the problem of difficult estimation of the appropriate amount to a certain extent, and pre-spreading is beneficial to reduce the dependence of the thermal paste on the assembly (such as the stiffness of the solid surface of the contact surface or the fastener structure and the magnitude and uniformity of the pressure that can be provided).

[0013] However, for plastic scrapers, in order to exert their proper spreading function, usage methods need to be formulated according to the characteristics of the thermal paste (such as consistency or adhesiveness) and the characteristics of the solid surface where the heat source and the heat sink are assembled (such as surface roughness or surface energy). For example, there are several disadvantages that need to be considered as follows:

[0014] ① High requirements for scraper usage skills:

[0015] The basic method of using the scraper is mainly to scrape from the center outwards, and bubbles and voids should be avoided as much as possible. However, sometimes reverse or multi-directional scraping is required. Users can form: the blade tip remains straight, or, under the action of the thumb pressing on the blade tip, a certain curvature of bending deformation is formed according to the pressure applied by the blade tip and the angle between the moving plastic scraper and the plate surface. Among them, compared with the straight shape, this bending deformation can spread the thermal paste more efficiently, and can apply pressure to the thermal paste over a larger area and more evenly. The better the adaptability (matching) of the degree of this bending deformation to the properties of the thermal paste, the higher the spreading efficiency and quality, and the lower the rework requirements for "scratches", "wire drawing", and "peeling". Practice and common knowledge have shown that this can significantly affect the spreading completion of thermal pastes such as the Shin-Etsu X23-7921-5 series, which are viscous, have strong shear resistance, are not easy to stick to the top surface of the chip but are easy to stick to the scraper. Using the straight shape method results in low spreading efficiency and quality. And during repeated spreading, it is very easy to cause rework due to "scratches", "wire drawing", and "peeling", and even the thermal paste needs to be removed, then the solid surface such as the chip surface is wiped clean with a cleaning cloth, and then an appropriate amount of new thermal paste is extruded again to repeat the spreading process.

[0016] In addition, during use, rapid spreading or excessive force should be avoided as much as possible, as this will introduce more closed bubbles to a certain extent.

[0017] ② It is difficult for the scraper to form a high-quality uniform layer and flat surface, and its robustness needs to be improved:

[0018] During the scraping process, the thickness uniformity and top surface flatness of the smeared layer need to be continuously adjusted, and the layer needs to be continuously thinned. The smeared layer obtained by scraping with the blade is subject to the dispersed phase structure, viscosity, and shear resistance of the thermal paste, as well as factors such as micro-pits and surface energy differences on the solid surface of the heat source. In addition, the tip of the blade is also subject to the flatness process and is microscopically uneven, making it easy to form "scratches" or "scraper filaments" (the scraper filaments are filaments that expose the solid surface of the heat source). Considering that even after the solid surface such as the heat source surface is leveled, there are still micro-pit arrays at the micron and / or nanometer levels. Therefore, the performance of its thickness uniformity and top surface flatness is often not ideal, such as surface scratches or even scraper filaments, or local depressions. Thus, the robustness of applying thermal paste with the blade needs to be improved. Practice and common knowledge have shown that these factors can significantly affect, for example, Shin-Etsu X23-7921-5 series thermal greases with high viscosity and high shear resistance, or phase change thermal greases such as Honeywell 7958-SP series.

[0019] ③ The smeared layer is sensitive to the pressure and shear force applied by the blade, making it difficult to continuously and stably apply the thermal paste, and it is not easy to spread and thin quickly, continuously, and stably:

[0020] During the thinning process, especially in the final stage of thinning, it is significantly sensitive to vertical pressure (which is likely to cause such scratches or scraper filaments), and is sensitive to the shear force of lateral scraping (which is likely to cause excessive scraping or the trailing edge to be pulled up and peeled). It is shown that the later the stage, the more sensitive and the more careful it needs to be. It can be seen that the pressure and shear force cannot be robustly and fully transmitted to the top surface, inside, and bottom surface of the smeared layer; the blade tip is bent and deformed when applying pressure, and the thermal paste is smeared in a sliding friction manner, which has a high degree of disturbance and even local destruction to the previous smeared layer. For example, in the later stage or even the final stage, several scratches or even scraper filaments are likely to form on its surface, especially affecting the application of dilutive thermal pastes such as liquid types. And some scratches or scraper filaments are also likely to enclose micro-bubbles during the clamping process, thereby reducing the thermal conductivity of the smeared layer. It can be seen that it is disadvantageous for both dilutive thermal pastes and high-viscosity thermal pastes. Among them, because the dilutive thermal paste has more solvents and weak shear resistance, it is more likely to produce scratches or scraper filaments; because the high-viscosity thermal paste has fewer solvents and strong shear resistance, it is more likely to pull up and peel the trailing edge during scraping (for example, the well-known viscous type silicone grease that is not easy to apply, which sticks to the blade and is not easy to stick to the CPU, such as the Shin-Etsu X23-7921-5 series, etc.). These are all disadvantageous for simple, fast, continuous, and stable spreading and thinning.

[0021] ④ Due to the above reasons, it is difficult to avoid enclosing micro-bubbles during the assembly and clamping of the radiator:

[0022] During the snap - fit process that is completed in a short period, due to the limited flatness of the surface layer and the micro - pits on the solid surface, micro - bubbles (cavities) are likely to be trapped and difficult to expel in the scratches, scraping lines or low - lying areas on the top surface of the pre - smeared layer, or in some of the micro - pits on the surface of the lower snap - fit solid. This means that these micro - bubbles form poor heat conductors, and at the same time, the anti - pumping ability of the pre - smeared layer during the high - low temperature cycle decreases. As the solvent volatilizes, the overall volume of the pre - smeared layer decreases, and the volume expansion and contraction of these micro - bubbles during the high - low temperature cycle further deteriorate the anti - pumping ability of the pre - smeared layer. In addition, the running - in process of the thermal paste is bound to involve the volume expansion, contraction, escape or merger of these micro - bubbles, making the running - in process complex and difficult to predict, and the running - in period prolonged. Eventually, the thermal conductivity and durability of the formed filling layer decrease rapidly.

[0023] It can be seen that the existing thermal paste application technology has at least the above - mentioned technical problems to be solved. However, how to overcome the picky assembly of the thermal paste on the radiator, and improve the existing application tools to reduce the requirements for application skills, especially the requirement for mastering the mutual adaptation between specific thermal paste, the characteristics of the assembled solid surface and the bending deformation degree of the pressure exerted on the blade tip of the scraper, so as to achieve high robustness of the application tool for laying the thermal paste; and reduce the trapped micro - bubbles, and improve the uniformity, flatness, compactness, adhesion, cohesion and resilience of the coating layer, and overcome the sensitivity of the existing pre - smeared layer to the pressure and shear force exerted by the scraper, making it difficult to continuously and stably apply the thermal paste, not easy to simply, quickly, continuously and stably spread and thin, and improve the tightness and anti - pumping ability during the work after the snap - fit assembly of the radiator, and make the running - in process meet the expectations and reduce the running - in period, so as to achieve high robustness in the performance of the thermal paste design, has become an urgent technical problem to be solved. Summary of the Invention

[0024] In view of this, the technical purpose of this application is to provide a pre - spreading tool for thermal paste to overcome the deficiencies of the existing application technology, and achieve overcoming the picky assembly of the thermal paste on the radiator, and improving the existing application tools to reduce the requirements for application skills, especially the requirement for mastering the mutual adaptation between specific thermal paste, the characteristics of the assembled solid surface and the bending deformation degree of the pressure exerted on the blade tip of the scraper, so as to achieve high robustness of the application tool for laying the thermal paste; and reduce the trapped micro - bubbles, and improve the uniformity, flatness, compactness, adhesion, cohesion and resilience of the coating layer, and overcome the sensitivity of the existing pre - smeared layer to the pressure and shear force exerted by the scraper, making it difficult to continuously and stably apply the thermal paste, not easy to simply, quickly, continuously and stably spread and thin, and improve the tightness and anti - pumping ability during the work after the snap - fit assembly of the radiator, and make the running - in process meet the expectations and reduce the running - in period, so as to achieve high robustness in the performance of the thermal paste design.

[0025] To achieve the technical object of the present application, the following technical solutions are adopted in the present application:

[0026] A pre-spreading tool for thermal paste is provided, characterized in that the pre-spreading tool includes: a working part having a working surface with a cylindrical smooth outer surface, the working surface being capable of forming repeated rolling to spread the thermal paste and adjust the dispersed phase structure of the thermal paste; a handheld part for holding and braking the pre-spreading tool so that the working surface forms the repeated rolling; and a connecting part for forming a movable connection between the working part and the handheld part so that the working surface forms the repeated rolling.

[0027] Optionally, the pre-spreading tool is characterized in that it further includes: the working surface is configured to have a constant diameter throughout or a shape change in a local section, and the shape change includes a diameter change, a rounded corner or a chamfer; and / or, the working surface is treated specially to have non-stick properties, and the special treatment includes grinding, polishing, coating, plating or modification; and / or, the working surface has a small curvature radius not less than 2 cm or a large curvature radius exceeding 2 cm; and / or, a housing is coupled outside the working surface as a protective layer or a new working surface.

[0028] Optionally, the pre-spreading tool is characterized in that it further includes: the material of the working surface or the new working surface includes polytetrafluoroethylene, high-density polyethylene, a nanotechnology coating, a silicone coating or a ceramic coating; or, the material of the working surface or the new working surface includes a metal material, a ceramic material or a plastic material.

[0029] Optionally, the pre-spreading tool is characterized in that it further includes: adjusting the dispersed phase structure of the thermal paste includes: reducing the particle spacing of the thermal conductive filler inside, on the top surface and on the bottom surface of the thermal paste; and re-adjusting the thermal conductive filler to form a framework structure, including small-particle-size particles squeezing into the gaps between large-particle-size particles, and a thermal conduction path is formed between the small-particle-size particles and the large-particle-size particles; and the stress migration of the matrix in the thermal paste.

[0030] Optionally, the pre-spreading tool is characterized in that it further includes: the thermal paste is classified by viscosity into: a liquid type less than 3 Pa·s; or a liquid-plastic state type of 3 Pa·s to less than 20 Pa·s; or a plastic state type of 20 Pa·s to less than 200 Pa·s; or a semi-solid state type not less than 200 Pa·s.

[0031] Optionally, the pre-spreading tool is characterized in that it further includes: the thermal paste is classified by viscosity and also includes: a semi-solid state type not less than 360 Pa·s.

[0032] Optionally, the pre-spreading tool is characterized by further comprising: a heating device for heating the working surface to heat the thermal paste in contact during operation, thereby enhancing the pre-spreading.

[0033] Optionally, the pre-spreading tool is characterized by further comprising: the heating device includes a heating part disposed on the inner periphery of the cylindrical smooth working surface.

[0034] Optionally, the pre-spreading tool is characterized by comprising: the thermal paste is a phase change silicone grease, or replaced by a thermal pad, or replaced by liquid metal.

[0035] Optionally, the pre-spreading tool is characterized by further comprising: a wiping cloth containing alcohol or lubricant for cooperating to wipe the working surface.

[0036] From the above technical solutions, it can be seen that the present application has the following beneficial effects:

[0037] Compared with the existing scraper whose blade tip exerts pressure to form a bending deformation for the purpose of facilitating the scraping and shifting of the thermal paste, the working surface with a cylindrical smooth outer surface in the pre-spreading tool provided by the present application is an improved development based on the bending deformation formed by the blade tip of the existing scraper, so as to form a working surface with a cylindrical smooth outer surface. Through the repeated rolling of the working surface, a low-disturbance foundation can be obtained, and a highly repeatable rolling friction method can be used to pre-spread the thermal paste. And based on this low-disturbance foundation, the thixotropy of the thermal paste is fully utilized to adjust the dispersed phase structure inside, on the top surface and on the bottom surface of the thermal paste, so as to promote the high-continuity, high-stability and high-robustness adjustment of the dispersed phase structure of the thermal paste under the influence of its own thixotropy, and realize that the spreading layer obtained under the previous rolling will form a rolling layer with better properties after the next rolling. This rolling method can improve the robustness of the thermal paste paving. During the whole process of thermal paste paving, especially in the later stage and even at the end stage of paving, it is possible to perform repeated rolling at a relatively fast speed and with any pressure of the hand, without worrying about the sensitivity of the scraper to pressure and shear force. The repeated rolling is also more beneficial (such as simply, quickly, funnily, continuously and stably) to convert the mechanical energy of the pre-spreading tool into the internal energy of the thermal paste, which further more advantageously softens the thermal paste and makes it easier to pre-spread.

[0038] The pre-spreading tool provided by the present application can continue to be repeatedly rolled even in the later stage or even the final stage of spreading. Even when the pre-spread layer has become thinner, with uniform thickness and can adhere tightly to the surface of the heat source, it can still be rolled repeatedly. However, the pre-spread layer will not be easily disturbed or even locally damaged by the subsequent rolling due to its thinness. That is, the degree of thinning of the pre-spread layer and the characteristics of the dispersed phase are easily inherited by the pre-spread layer formed by the subsequent rolling, so as to continuously further optimize the thinness, further optimize the thickness uniformity, further optimize the adjustment of the dispersed phase structure, and further optimize the degree of fitting between the bottom surface of the pre-spread layer and the micro-pits (or exclude gas to build more heat conduction paths). However, in the later stage or even the final stage of paving, the scraping method shows the opposite situation due to its sensitivity to aspects such as thinness and force.

[0039] By repeatedly rolling with the working surface of the present application, the force (including pressure and shear force) can be fully, continuously, and persistently applied to the pre-spread layer, and the relatively weaker shear force formed compared to the scraper can act on the pre-spread layer with high stability, reliability, continuity, and persistence. Finally, the dispersed phase structure inside, on the top surface, and on the bottom surface of the pre-spread layer is more fully and better adjusted (such as the filler spacing is reduced, the filler spacing is uniform, the large and small filler skeleton structures are re-distributed, the cohesion, compactness, adhesion, and resilience), as well as the flatness and smoothness of the top surface and the embedding degree of the bottom surface (the degree and proportion to which the pre-spread layer can overcome the shear force and be pressed into the micro-pits under repeated rolling). Among them, the flatness of the top surface obtained and the unexpectedly obtained smoothness on the basis of the flatness can reduce or avoid the formation of closed micro-bubbles after buckling; the embedding degree of the bottom surface can exclude more gas in the micro-pits, thereby forming more heat conduction paths, and forming an anchoring effect of press-fitting and biting, thereby generating a certain negative pressure adsorption effect against peeling, which can improve the anti-pumping ability during the high and low temperature cycling process of the work. The increase in compactness and cohesion realizes the improvement of the bonding force of the pre-spread layer, thereby enhancing the integrity of the sheet-like thin layer of the pre-spread layer. At the same time, the filler spacing is reduced, the filler spacing is uniform, and the large and small filler skeleton structures are re-distributed, and the thermal conductivity, cohesion, compactness, adhesion, and resilience of the pre-spread layer are all improved, and unexpectedly, the top surface of the pre-spread layer shows a certain degree of smoothness and reflectivity. Thus, the running-in period can be expected and shortened, the attenuation slows down, and the thermal performance and durability are improved.

[0040] During the scraping process of the existing scraper on the smearing layer, continuous adjustment of thickness uniformity and flatness, as well as continuous thinning, are carried out. However, it shows sensitivity to pressure (easily causing scratches or scraping wires), sensitivity to the shear force during scraping (if it is too thin, it is easy to cause excessive scraping, or if it is too viscous, the shear resistance is strong and it is difficult to scrape smoothly, resulting in, for example, the trailing edge of the tool tip being easily pulled up to cause skinning), and it becomes more sensitive and requires more care in the later stage. It can be seen that it is impossible to robustly transfer the pressure and shear force to the top surface, interior, and bottom surface of the smearing layer sufficiently. The bending deformation formed by the pressure on the scraper head is used to smear the thermal paste in a sliding friction manner, which has a high degree of disturbance and even local damage to the previous smearing layer.

[0041] The pre-spreading tool provided by the present application can overcome the deficiencies of the existing smearing technology, achieve overcoming the picky radiator assembly of the thermal paste, and improve the existing smearing tool to reduce the requirements for operating skills, especially the mastery requirements for the mutual adaptation between specific thermal paste, the characteristics of the assembled solid surface, and the degree of bending deformation caused by the pressure on the scraper head, so as to achieve the high robustness of the smearing tool for the paving of the thermal paste; and by means of repeated rolling, the microbubbles are pre-reduced (to achieve fewer requirements for bubble discharge during the assembly and buckling of the radiator), and the uniformity, flatness, smoothness, compactness, adhesiveness, cohesion, and resilience of the pre-spreading layer are improved, and the sensitivity of the existing smearing layer to the pressure and shear force applied by the scraper is overcome, making it difficult to continuously and stably apply the force to the thermal paste, not easy to simply, quickly, continuously, and stably spread and thin, and improving the tightness and anti-pumping ability during the work after the assembly and buckling of the radiator, and making the running-in process meet the expectations and reducing the running-in period, so as to achieve the high robustness of the performance of the thermal paste design.

[0042] In addition, compared with the existing scraper, the pre-spreading tool provided by the present application can make the paving of the thermal paste simpler, more efficient, and faster, can simply and quickly fuse and flatten the multiple added doses, and can well fill the gaps (or fill the low-lying areas or local exposures such as scraping wires or peeling), and overcome the problem of difficult paving of the highly viscous semi-solid type thermal paste with high shear resistance, so as to reduce the requirements for taking into account the thermal performance and paving difficulty during the research and development and preparation of the thermal paste.

[0043] More features and benefits of the present application will be described in detail in the subsequent specific implementation part. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 Shows the development diagram of the pre-spreading tool of the present application;

[0045] Figure 2 Shows a schematic diagram of the obtained effect after multiple scrapings of an embodiment of the existing scraper;

[0046] Figure 3Shows a schematic diagram of an obtained effect after repeated rolling of the pre-spreading tool embodiment of the present application;

[0047] Figure 4 Shows another schematic diagram of an obtained effect after repeated rolling of the pre-spreading tool embodiment of the present application;

[0048] Figure 5 Shows a micrograph of the dispersed phase structure effect after multiple scraping of the scraper embodiment of the prior art;

[0049] Figure 6 Shows a micrograph of the dispersed phase structure adjustment effect after repeated rolling of the pre-spreading tool embodiment of the present application;

[0050] Figure 7 Shows an enlarged photograph of the wire scraping generated after multiple scraping of the scraper embodiment of the prior art.

[0051] Reference numerals:

[0052] Figure 1 Among them, 10, a scraper used in a straight plate shape; 20, a scraper with a bent and deformed tool head; 30, a working surface with a smooth outer surface in a cylindrical shape; 100, a solid surface;

[0053] Figure 2 Among them, 21, a scraping layer; 22, a solid surface with micro-pits; 23, micro-bubbles enclosed in the micro-pits on the solid surface 22; 24, a low-lying area located locally on the top surface of the scraping layer 21;

[0054] Figure 3 Among them, 31, a pre-spreading layer; 32, a solid surface with micro-pits;

[0055] Figure 4 Among them, 41, large-grain particles in the pre-spreading layer; 42, small-grain particles in the pre-spreading layer; 43, a heat conduction path indicated by an arrow in the pre-spreading layer. Detailed implementation manners

[0056] In order to make the purpose, technical solutions and beneficial effects of the present application clearer, the present application will be further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The specific embodiments described herein are only used to explain the present application and are not used to limit the present application. All other embodiments obtained by those of ordinary skill in the art in the technical field of the present application without creative efforts based on the embodiments of the present application belong to the scope of protection of the present application.

[0057] In the case of no conflict, the embodiments in the present application and the features in the embodiments may be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0058] Please refer to Figure 1 , which shows a development schematic diagram of the pre-spreading tool of the present application. As Figure 1 shown, it shows subfigures (a), (b) to (c), which are improvement development schematics of the pre-spreading tool of the present application, all in side view.

[0059] Among them, subfigure (a) shows a scraping method in which a scraper 10 (such as a plastic scraper or a metal scraper) is kept in a straight plate shape for use, and a solid surface 100. There is a scraping layer on the top surface of the solid surface 100. It can be seen that in one scraping operation, the thickness of the scraping layer at the trailing edge of the top end of the tool head (in the forward direction) becomes thinner (due to being scraped and shifted), while the scraping layer at the leading edge (not yet scraped) remains thick.

[0060] Subfigure (b) shows another scraping method in which a scraper 20 (such as a plastic scraper) forms a curved deformation with a certain curvature by pressing the tool head, and a solid surface 100, which is a further improvement and development compared to the straight plate-shaped tool head in subfigure (a). There is a scraping layer on the top surface of the solid surface 100. It can be seen that in one scraping operation, the thickness of the trailing edge of the curved deformation scraping part (in the forward direction) becomes thinner (due to being scraped and shifted), while the scraping layer at the leading edge (not yet scraped and shifted) remains thick.

[0061] Subfigure (c) shows a working surface 30 with a cylindrical smooth outer surface in the pre-spreading tool of the present application, and a solid surface 100, which is a further improvement and development compared to the curved deformation with a certain curvature formed by pressing the tool head in subfigure (b). The improvement and development include changing the curvature of the working surface and changing the friction method from sliding friction to rolling friction. The radius of curvature of the working surface 30 is the radius R of the cylinder; there is a pre-spreading layer on the top surface of the solid surface 100; the solid surface 100 can be, for example, a bare silicon wafer of a CPU, a copper cover plate, or a copper cover plate with a nickel-plated layer. It can be seen that there is at most a nearly tangent contact in a linear or narrow strip shape between the working surface 30 and the top surface of the pre-spreading layer. Therefore, it can be known that in one rolling process, the thickness of the trailing edge pre-spreading layer at the contact part (in the rolling direction) becomes thinner (due to being rolled), while the pre-spreading layer at the leading edge (not yet rolled) remains thick; therefore, compared with the scraper, its contact area is smaller, the shear force applied is smaller, and the adhesiveness of the thermal paste is smaller, but the force is applied more gently, more slowly and continuously, and with less disturbance to gradually optimize and adjust the dispersed phase structure. This nearly tangent contact becomes more obvious as the pre-spreading layer is gradually extended and thinned and becomes more compact.

[0062] In the present application, existing scrapers such as Figure 1The middle scraper, etc. can also be replaced with an existing squeegee, facing the same situation as the scraper described in this application. In Figure 1 Replacing the middle scraper with a squeegee will make it easier to understand the improvement and development schematic diagram of this application.

[0063] It can be seen that the technical concept of this application is mainly to provide a working surface with a cylindrical smooth outer surface in the pre-spreading tool, which is an improvement and development of further bending deformation on the basis of the bending deformation formed by the pressure of the tool head of the existing scraper, so as to form a working surface with a cylindrical smooth outer surface. Through the repeated rolling of the working surface, a low-disturbance base can be obtained, and a highly repeatable rolling friction method can be used to pre-spread the thermal paste. And based on this low-disturbance base, the thixotropy of the thermal paste is fully utilized to adjust the dispersed phase structure inside, on the top surface and on the bottom surface of the thermal paste, so as to promote the high-continuity, high-stability and high-robustness adjustment of the dispersed phase structure of the thermal paste under the influence of its own thixotropy, realizing that the spreading layer obtained under the previous rolling will form a rolling layer with better properties after the next rolling. This rolling method can improve the robustness of the thermal paste paving. In this application, robustness can be understood as the adaptability of being less (or not) picky about the environment (such as the viscosity of the thermal paste, the solid surface characteristics of the assembled contact surface, and the stiffness and fastening pressure of the fastener) in some embodiments. During the whole process of thermal paste paving, especially in the later stage and even at the end stage of paving, it is possible to perform repeated rolling at a relatively fast speed and with any hand pressure, without worrying about the sensitivity of the scraper to pressure and shear force.

[0064] The applicant found through experiments that even in the later stage and even at the end stage of paving, when the pre-spreading layer is already thin, has a uniform thickness and can adhere relatively tightly to the heat source surface, it can still be repeatedly rolled. However, the pre-spreading layer will not be easily disturbed or even locally damaged by the subsequent rolling because it is already thin, that is, the thinning and properties of the pre-spreading layer are easily inherited by the subsequent rolling, so as to continuously optimize the thinness further, optimize the thickness uniformity further, and optimize the fitting degree between the bottom surface of the pre-spreading layer and the micro-pits (or exclude gas to build more heat conduction paths) further. However, the scraping method shows the opposite situation in the later stage and even at the end stage of paving.

[0065] Based on this, by repeatedly rolling the working surface, the force (including pressure and shear force) can act on the pre-spread layer fully, continuously, and persistently. In addition, the relatively weaker shear force formed compared to the squeegee can act on the pre-spread layer with high stability, reliability, continuity, and persistence. The repeated rolling is also more beneficial (such as simply, quickly, efficiently, continuously, and stably) to convert the mechanical energy of the pre-spreading tool into the internal energy of the thermal paste, which further facilitates the softening of the thermal paste. Ultimately, the internal, top, and bottom dispersed phase structures of the pre-spread layer are adjusted more fully and better (such as the reduction of filler spacing, the uniformity of filler spacing, the redistribution of the large and small filler skeleton structures, cohesion, compactness, adhesion, resilience), as well as the flatness and smoothness of the top surface and the embedding degree of the bottom surface (the degree and proportion to which the pre-spread layer can overcome the shear force and be pressed into the micro-pits under repeated rolling). Among them, the flatness of the top surface obtained and the unexpectedly obtained smoothness on the basis of the flatness can reduce or avoid the formation of closed micro-bubbles after crimping; the embedding degree of the bottom surface can expel more gas in the micro-pits, thereby forming more heat conduction paths, and forming a pressing and engaging anchoring effect, thereby generating a certain negative pressure adsorption effect against peeling, which can improve the anti-pumping ability during the high and low temperature cycling process of the work. The increase in compactness and cohesion realizes the improvement of the bonding force of the pre-spread layer, thereby enhancing the sheet-like thin layer integrity of the pre-spread layer. At the same time, with the reduction of filler spacing, the uniformity of filler spacing, and the redistribution of the large and small filler skeleton structures, the thermal conductivity, cohesion, compactness, adhesion, and resilience of the pre-spread layer are all improved, and unexpectedly, the top surface of the pre-spread layer shows a certain smoothness and reflectivity. As a result, the running-in period can be expected and shortened, the attenuation slows down, and the thermal performance and durability are improved.

[0066] During the scraping process of the existing scraper on the scraping layer, it is necessary to continuously adjust the thickness uniformity and flatness and continuously scrape thinly. However, during the thinning process, especially in the final stage of the thinning process, it is significantly sensitive to vertical pressure (which is likely to cause scratches or scraping lines), and is sensitive to the shear force of horizontal scraping (which is likely to cause excessive scraping or the trailing edge to be pulled up and peeled). All of these show that the later the stage, the more sensitive and the more careful it needs to be. It can be seen that the existing scraper cannot robustly transfer the pressure and shear force to the top surface, inside and bottom surface of the scraping layer; the bending deformation caused by the pressure on the cutter head of the scraper scrapes the thermal paste in a sliding friction manner, resulting in a relatively high disturbance or even local damage to the previous scraping layer. Especially in the later stage or even the final stage, several scratches or even scraping lines are likely to form on its surface; this will particularly affect the application of diluent thermal pastes such as liquid types, and some scratches or scraping lines are also likely to enclose microbubbles during buckling, thereby reducing the thermal conductivity of the scraping layer. It can be seen that it is disadvantageous for both diluent thermal pastes and highly viscous thermal pastes. Among them, because the diluent thermal paste has more solvents and weak shear resistance, it is more likely to produce scratches or scraping lines; because the highly viscous thermal paste has fewer solvents and strong shear resistance, it is more likely to pull up and peel the trailing edge during scraping (for example, the well-known viscous silicone grease that is not easy to apply, which sticks to the scraper and is not easy to stick to the CPU, such as Shin-Etsu X23-7921-5 series, etc.). All of these are disadvantageous for simple, rapid, continuous and stable thinning.

[0067] In addition, compared with the existing scraper, the pre-spreading tool provided in this application can make the paving of the thermal paste simpler, more efficient and faster, and can quickly and simply achieve the fusion and leveling of adding new doses on the pre-spreading layer (while the existing scraper is difficult to adapt to this situation of highly viscous silicone grease), and can well fill the gaps by rolling (locally exposed such as scraping lines or peeling), and overcome the problem of difficult paving of highly viscous semi-solid thermal pastes with high shear resistance, so as to reduce the requirements for balancing the thermal conductivity and paving difficulty during the research and development and preparation of the thermal paste.

[0068] For example, in some embodiments of the present application, the pre-spreading tool is applied to a highly viscous semi-solid type thermal paste, which generally exhibits high thermal conductivity and high shear resistance. Therefore, compared with diluent liquid or plastic type thermal pastes, more small air cavities are likely to form in the gaps between the filler particles on the surface of the paving layer, and small air cavities in the micro-pits on the solid surface such as the heat source are likely to be pressed on the bottom surface. The bottom surface needs to overcome the high shear resistance of the thermal paste itself to fully press into the small air cavities and discharge the gas. However, in the research and development design, it is necessary to consider the problem that it is not easy to apply on the heat source surface that is not easy to stick, such as the exposed silicon wafer of the CPU (such as easy to peel off), or it is difficult to complete high-quality (such as not easy to scrape and move to obtain uniformity and flatness) application. The existing scraper cannot transfer the pressure and shear force to the top surface, inside and bottom surface of the scraping layer with high robustness. The scraper head is pressed to form a bending deformation to scrape the thermal paste in a sliding friction manner, which has a high disturbance and even local destruction to the previous scraping layer. The pre-spreading tool of the present application has high robustness (such as high adaptability) to this, and can obtain a pre-paving layer simply, quickly and efficiently. The pre-spreading tool of the present application shows excellent adaptability to the viscous semi-solid type thermal paste, and this viscous semi-solid type thermal paste is exactly the type of thermal paste that is disadvantageous for existing coating tools such as scrapers. In addition, for diluent liquid or plastic type thermal pastes, the existing scraper also shows an unfavorable side in thinning, especially in the later stage or the finishing stage of paving. It is necessary to worry about the sensitivity of the already relatively thin coating layer to the pressure and shear force of the scraper, and prevent wire scraping, scratching or excessive force application resulting in local strip-shaped scraping. However, the cylindrical smooth working surface of the pre-spreading tool in the present application can be repeatedly rolled at a relatively fast speed and any hand pressure. Especially when the working surface of the pre-spreading tool in the present application has the functions of non-stickiness or chamfering, etc., it is bound to have a more efficient and simple spreading experience.

[0069] Compared with the existing scraping tools, the pre-spreading tool provided in this application can make more full, continuous, and sustained use of the thixotropy of the thermal paste through repeated rolling. For a thermal paste such as thermal silicone grease, thixotropy means that when an external force is applied, the flow of the thermal paste gradually softens, manifested as a decrease in viscosity. However, once it is at rest, after a short period of time, the consistency increases again (recovers), that is, the property of changing instantly upon touch. This characteristic of the thermal paste is manifested in that when you place it there, it does not flow, but when you apply it, it is very easy to spread. It can be seen that the pre-spreading tool provided in this application can pre-spread the thermal paste faster, more simply, with a higher frequency, and at the same time with less disturbance. Therefore, during the process of rapid and high-frequency repeated rolling, the thermal paste rolled over by the working surface in the first direction is stressed and softened. Before its consistency can recover, the working surface returns to roll again, and the viscosity decreases again. This repeated rolling method can make more full use of thixotropy, undoubtedly improving the optimization and adjustment efficiency of the dispersed phase structure of the thermal paste.

[0070] Please refer to Figure 2 , which shows a schematic diagram of the obtained effect after multiple scraping operations of an existing scraping tool embodiment. As Figure 2 shown, it includes: a scraping layer 21, a solid surface 22 with micro-pits, micro-bubbles 23 enclosed in the small air cavities in the micro-pits, and a low-lying area 24 on the top surface of the scraping layer 21. It can be seen that after multiple scraping operations, the thermal paste on the bottom surface of the scraping layer 21 continuously overcomes its own shear force and is gradually pressed into the micro-pits of the solid surface 22, thereby expelling the gas in the micro-pits to a certain extent and forming a certain heat conduction path. However, due to the adverse side of the existing scraping tool during thinning, especially in the later stage or even the final stage of scraping, it is necessary to worry about the sensitivity of the already relatively thin scraping layer 21 to the pressure and shear force applied by the scraping tool, and it is necessary to prevent wire scraping, scratching, or excessive force application resulting in local strip-shaped scraping removal. It can be seen that the scraping method cannot robustly transfer the pressure and shear force to the top surface, inside, and bottom surface of the scraping layer sufficiently. The pressure applied by the scraping tool head causes bending deformation and scrapes the thermal paste in a sliding friction manner, resulting in a relatively high disturbance and even local damage to the previous scraping layer.

[0071] This is especially obvious for high-viscosity and high-shear-strength thermal pastes such as plastic or semi-solid types. Therefore, during the process of the existing scraping method, it is easy to cause the trailing edge of the tool head to be pulled up. It is precisely because the pressure and shear force cannot be fully, continuously, continuously, and stably applied to the pre-spreading layer (as in the solution of this application), and thus it is difficult to avoid enclosing micro-bubbles when forming assembly buckling, as Figure 2 the micro-bubbles 23 enclosed in the small air cavities in the micro-pits, which makes the overall anchoring effect of the existing scraping layer 21 insufficient and needs to be improved.

[0072] Please refer toFigure 3 , which shows a schematic diagram of the obtained effect after repeated rolling of an embodiment of the pre-spreading tool of the present application.

[0073] As Figure 3 shows, including: a pre-spreading layer 31 and a solid surface 32 with micro-pits. It can be seen from Figure 3 (compared with Figure 2 ), under the action of repeated rolling of the present application, more thermal paste on the bottom surface of the pre-spreading layer 31 continuously overcomes the shear force and is gradually pressed into the micro-pits, thereby further exhausting the gas in the micro-pits to a greater extent, forming more good heat conduction paths, and forming an anchoring effect of the bottom surface of the pre-spreading layer 31 being embedded and engaged, achieving better exhaustion of the air in the micro-pits, and then forming a pre-spreading layer 31 that adheres to the solid surface 32 under a better negative pressure effect, so as to achieve better anti-peeling ability during the pre-spreading process, for example, and anti-pumping ability during the thermal cycling operation.

[0074] Please refer to Figure 4 , which shows another schematic diagram of the obtained effect after repeated rolling of an embodiment of the pre-spreading tool of the present application.

[0075] As Figure 4 shows, including: large-grain particles 41 and small-grain particles 42 inside the pre-spreading layer, and a heat conduction path 43 indicated by the arrow. It can be seen that under the action of repeated rolling of the working surface of the present application, the filler particles inside the pre-spreading layer, among which the small-particle fillers continuously overcome the frictional force, are repeatedly squeezed and adjusted and squeezed into the gaps between the large-particle fillers, thereby forming more heat conduction paths with more improved internal compactness. In addition, compared with the scraping method, the compactness of the top and bottom surfaces of the pre-spreading layer will also be more improved. The scraping method can only limitedly adjust the dispersed phase structure inside the thermal paste. The repeated rolling of the present application shows superiority in flexibility, frequency (or number of smearing times) and high robustness suitable for electronic packaging and can reflect a better performance limit that can be achieved.

[0076] Please refer to Figure 5 , which shows a micrograph of the dispersed phase structure effect after multiple smearing of an embodiment of a scraper in the prior art.

[0077] From Figure 5It can be seen that after the thermal paste is repeatedly scraped and redistributed by the existing scraper, the surface of the smeared layer shows a relatively dispersed distribution of filler particles, with large particle spacing and uneven spacing. In particular, the particles in the top layer are dispersed and uneven, and there are small cavities distributed among them. Moreover, the matrix does not receive sufficient force to be extruded to the periphery at the same height as the top layer of particles. Therefore, it is considered that after actual measurement, it is precisely the formation of, for example, diffuse reflection that makes it difficult to present smoothness or even reflectivity on the top surface of the smeared layer of the existing scraper macroscopically. In addition, scraping wires are likely to be generated on the surface of the smeared layer, or the flatness of scraping is limited and there are easily local low-lying areas. Therefore, during the snap-fit process of assembly completed in a short period, these uneven concave areas are easily sealed into microbubbles.

[0078] Please refer to Figure 6 , which shows a micrograph of the effect of the dispersed phase structure adjustment after repeated rolling of an embodiment of the pre-spreading tool of the present application.

[0079] From Figure 6 it can be seen that (compared with Figure 5 ), after the repeated rolling of the present application, the surface of the pre-spreading layer shows a relatively aggregated (or converged) distribution of filler particles, with closer particle spacing and more uniform spacing. Moreover, the surface of the pre-spreading layer shows that the tops of the filler particles are basically at the same height. Therefore, during the snap-fit process of assembly completed in a short period, the surface of the pre-spreading layer is not easily sealed into microbubbles.

[0080] As Figure 6 shows, the surface shows a relatively aggregated (or converged) distribution of filler particles, with closer particle spacing and more uniform spacing. It is considered that during the repeated rolling process, when the pre-spreading layer is stressed, the matrix is stressed first, and then the thermal conductive filler skeleton is stressed. As the repeated rolling progresses, the thermal conductive filler skeleton starts to be stressed more. The matrix can migrate downward after being compressed, squeeze into the micro-pits through the bottom surface of the pre-spreading layer, migrate upward to the top surface of the pre-spreading layer and fill the gaps between the flat particles on the top surface. However, for the existing smearing method, there are cavities in the gaps between the top surface particles, and even some particles protrude locally without the matrix around them. From this, it can also be known that the adhesion, compactness, and cohesion of the pre-spreading layer formed by the repeated rolling of the present application are better. It can reflect the stress migration of the matrix in the thermal paste described in the present application.

[0081] In addition, during the gradual thinning of the pre-spreading layer, accompanied by the re-adjustment of the dispersed phase structure, including the reduction of the particle spacing of the thermal conductive fillers inside and on the top and bottom surfaces of the thermal paste, and the re-adjustment of the thermal conductive filler to form a skeleton structure. For example, small-particle-size particles squeeze into the gaps between large-particle-size particles, and then thermal conductive paths are formed between the small-particle-size particles and the large-particle-size particles, and these thermal conductive paths are more numerous than before the adjustment. During the gradual thinning process of the pre-spreading layer, the prior thick pre-spreading layer transitions to the subsequent thin pre-spreading layer, but from Figure 5It is not shown that the particles of the thermal conductive filler become more dispersed (i.e., become more discrete and sparse) synchronously as the pre-spread layer is rolled and extended. It is considered that compared with the latter, the former can be regarded as having more sub-layers with a thickness of d. For example, the former can be divided into M sub-layers with a thickness of d, while the latter can be divided into N sub-layers with a thickness of d (M > N). The particles in each sub-layer of the former are sparser than those in each sub-layer of the latter. However, under the repeated rolling action, the particles in each sub-layer of the former tend to migrate and form intersections more strongly along the thickness direction among the thickness direction and the facing direction of the pre-spread layer. Therefore, from Figure 5 It is not shown that the particles of the thermal conductive filler become more dispersed (i.e., become more discrete and sparse) synchronously as the pre-spread layer is rolled and extended. Instead, as observed above, the surface shows a relatively aggregated (or concentrated) distribution of the filler particles, with closer particle spacing and more uniform spacing.

[0082] In addition, Figure 6 For the pre-spread layer in , at the macroscopic level, the surface flatness is visually very high. In addition, unexpectedly, the smooth and bright texture (i.e., smoothness or finish) of the surface is observed, and there is a certain reflectivity.

[0083] While Figure 5 For the existing scraping layer in , at the macroscopic level, locally scratched wires or low-lying areas can be visually seen on the surface layer, and the surface flatness is relatively poor. It is difficult to achieve smoothness and reflectivity due to diffuse reflection on the surface. Figure 4 These macroscopic manifestations of also indirectly reflect that there are more cavities or grooves formed by the particles on the top surface of the scraping, and these cavities or grooves are not fully filled by the matrix. Therefore, the surface does not show smoothness and reflectivity as a whole. Above Figure 4 and Figure 5 From the measured content and comparison of and , it can be seen that they are all manifestations of adjusting the dispersed phase structure described in this application.

[0084] Please refer to Figure 7 , which shows an enlarged photo of the scratched wires generated after multiple scrapings of an existing scraper embodiment of the prior art.

[0085] From Figure 7 it can be seen that after multiple scraping and re-distribution of the thermal paste by the existing scraper, the surface layer of the scraping layer shows a certain number of scratches and small cavities between particles caused by unevenness. The disadvantages of these scratches and small cavities between particles are that during the buckling process of assembling the radiator in a short time, Figure 7The pre-spread layer shown will inevitably be sealed into micro-bubbles (cavities) in the scratches on the top surface of the spread layer, the small air cavities between particles, and some of the micro-pits on the assembled solid surface due to the limited flatness of the surface layer and the micro-pits on the assembled solid surface. This means that the micro-bubbles will form poor heat conductors, and at the same time, the anti-pumping ability of the pre-spread layer during the high and low temperature cycling process will decrease. As the solvent volatilizes, the overall volume of the pre-spread layer will decrease, and the volume expansion and contraction of the micro-bubbles during the high and low temperature cycling will further deteriorate the anti-pumping ability of the pre-spread layer. In addition, the running-in process of the thermal paste will inevitably involve the volume expansion and contraction, escape or merger of the micro-bubbles, and thus the running-in process becomes complex and difficult to predict, and the running-in period is extended. Eventually, the thermal conductivity and durability of the formed filling layer will be accelerated to decrease.

[0086] It should be added that, as is well known, thermal pastes such as thermal silicone grease usually consist of a liquid-phase polymer matrix (such as silicone oil or organosiloxane) and thermal conductive fillers. Thermal silicone grease generally consists of at least two parts and usually consists of four parts: matrix silicone oil, fillers, stabilizers and other additives. Commonly used matrices include: dimethyl silicone oil, methylphenyl silicone oil, long-chain alkyl silicone oil, fluorohydrocarbon silicone oil, etc. Common thermal conductive fillers mainly include: metals, such as silver, copper or aluminum, etc.; ceramics, such as boron nitride, aluminum nitride, silicon nitride, alumina, zinc oxide, beryllium oxide or silicon dioxide, etc.; carbonaceous materials, such as graphite, graphene, carbon nanotubes or carbon black, etc.

[0087] After long-term storage, the matrix and the fillers may separate, affecting the uniformity of the thermal paste. However, through the repeated rolling of this application, the dispersed phases of the matrix and the fillers can be readjusted, improving the uniformity and low thermal resistance performance of the thermal paste, including improving the reduction of the filler particle spacing, the pressing of small particles into the gaps between large particles to form more heat conduction paths, the compactness, the cohesion, the resilience, etc. High compactness can, to a certain extent, reduce the drying (Dry Out) speed of the liquid phase such as the solvent inside the filling layer during the working process. In addition, for problems such as oil leakage, pumping out, drying or powdering of thermal silicone grease and other thermal pastes, the key to improving these problems is to improve the cohesion of the thermal paste. And to improve the cohesion of the thermal paste, the key is to improve the compatibility and binding force between silicone oil and other matrices and the thermal conductive fillers. Through the repeated rolling of this application, the dispersed phases of the matrix such as silicone oil and the fillers can be readjusted, thereby improving the cohesion of the thermal paste to a certain extent.

[0088] It should be emphasized that in this application, the adjustment of the dispersed phase structure of the thermal paste includes, but is not limited to: reducing the particle spacing of the thermal conductive fillers inside, on the top surface, and on the bottom surface of the thermal paste; and readjusting the framework structure formed by the thermal conductive fillers. For example, small-sized particles can be squeezed into the gaps between large-sized particles, and more thermal conduction paths are formed between the small-sized particles and the large-sized particles. These thermal conduction paths in this application can achieve more than those achievable by the scraping method, and the thermal conduction intensity formed by these thermal conduction paths in this application is better. Preferably, it may further include: under the action of repeated rolling, the bottom surface overcomes its own shear resistance and is gradually pressed into the small air cavities of the micro-pits, and at the same time, the gas in the small air cavities is gradually discharged, thereby forming an anchoring effect. It can be seen that the anti-peeling ability or anti-pumping ability is improved compared with the existing scraping method. In addition, the matrix can migrate downward under the action of repeated rolling and be squeezed into the micro-pits through the bottom surface of the pre-spread layer. Preferably, it may further include: under the action of repeated rolling, the filler particles on the top surface are distributed in a more aggregated (or converged) manner, the particle spacing is closer and more uniform, and at the same time, the matrix can migrate upward under the pressure and come to the top surface of the pre-spread layer and fill the gaps between the flat particles in the top layer, that is, the matrix migrates upward into the circumferential gaps of the top layer of particles, thereby eliminating the small air cavities formed by the gaps between the top layer of particles. At the same time, it is also considered an important reason for the unexpectedly obtained smoothness and reflectivity of the top surface of the pre-spread layer. The obtained smoothness, reflectivity, and their mechanisms, etc., were not expected before actual measurement.

[0089] In this application, the axial length of the pre-spreading tool is not limited and can be determined according to the area or shape of the solid surface to be spread. The larger the solid surface, the larger the axial length of the pre-spreading tool can be to obtain high efficiency. The pre-spreading tool has a high efficiency in pre-spreading thermal paste on the copper top cover of a processor chip such as a CPU or GPU, and a better user experience, such as being less likely to peel off.

[0090] In this application, the adjustment of the dispersed phase structure of the thermal paste can make full use of the composition and structure characteristics of the thermal paste, such as the sequence of the force responses of the matrix and the filler when the pre-spread layer is stressed, and the re-adjustment of the particle spacing and the distribution of large and small particles formed by the better stress of the filler particles forming the framework after repeated rolling, etc. It can also make full use of the thixotropy of the thermal paste to achieve the better technical effects described in this application. It can also make full use of the more favorable stress compared with the existing scraping method to increase the internal energy, that is, this application can transfer mechanical energy to the paving layer more favorably and fully and convert it into internal energy, for example, a certain degree of temperature increase to achieve better spreading efficiency and effect.

[0091] The stress-induced migration of the matrix in the thermal paste of the present application can be, for example, that the matrix gradually migrates upward after being stressed to the periphery of the top layer of thermal conductive filler particles and / or gradually migrates downward into the micro-pits on the solid surface; or it can be that the matrix gradually adjusts the bond with the thermal conductive filler particles after being stressed, forming an improved cohesion, adhesion, and compactness of the thermal paste, as well as improving, for example, the anti-peeling ability and anti-shearing ability during the paving process, and improving the anti-pumping ability during the thermal cycling process.

[0092] The thermal paste in the present application can be, for example, a thermal gel or a thermal silicone grease. For example, the former can be formed by directly mixing thermal conductive fillers and short-chain small molecule silicone resins; the latter can be formed by first cross-linking those silicone oil small molecules into ultra-long chain macromolecules and then mixing them with thermal conductive fillers. The thermal paste in the present application can also be, for example, a liquid metal. The liquid metal is, for example, a gallium-based alloy type liquid metal.

[0093] In some embodiments of the present application, the pre-spreading tool includes: a thermal paste, which is a thermal silicone grease.

[0094] In some other embodiments of the present application, the pre-spreading tool includes: a thermal paste, which is a thermal silicone grease; the thermal paste is classified by viscosity as including: a liquid type less than 3 Pa·s; or a liquid-plastic state type from 3 Pa·s to less than 20 Pa·s; or a plastic state type from 20 Pa·s to less than 200 Pa·s; or a semi-solid state type not less than 200 Pa·s. As per research and actual measurement, as the viscosity increases, the anti-shearing abilities of different types of thermal pastes are different, and the scraping and moving abilities and effects of existing scrapers show differences, and the higher the viscosity of the thermal paste, the more unfavorable it is. Existing scrapers are particularly disadvantageous for high-viscosity type thermal pastes such as semi-solid state thermal pastes. For example, existing scrapers show an unfavorable side for the generally recognized difficult-to-apply semi-solid state thermal pastes such as the Shin-Etsu X23-7921-5 series, which has a high viscosity, strong anti-shearing ability, and is generally recognized as not easily sticking to the top surface of the chip but easily sticking to the scraper. However, research tests show that the pre-spreading tool of the present application shows high robustness (such as high adaptability) to these different types of thermal pastes. In short, the more unfavorable the type of thermal paste for existing scrapers, such as high-viscosity semi-solid state thermal pastes, the more favorable the pre-spreading tool of the present application shows, thus achieving what existing scrapers cannot. Especially when the working surface of the pre-spreading tool in the present application has the functions of non-stickiness or chamfering, etc., it is bound to have a more efficient and simple spreading experience. In addition, for example, the liquid type or liquid-plastic state type has more solvents and weaker anti-shearing ability, constituting a dilutive or dilution type of thermal paste; while the plastic state type or semi-solid state type has fewer solvents and stronger anti-shearing ability, constituting a high-viscosity or high-viscosity type of thermal paste. In addition, for example, the viscosities of some semi-solid state thermal pastes of brands such as Shin-Etsu with high viscosity and high anti-shearing ability reach 200 Pa·s or above.

[0095] In some other embodiments of the present application, the pre-spreading tool includes: thermal paste, which is thermal silicone grease; the thermal paste can also be classified by viscosity and includes: a semi-solid type with a viscosity of not less than 360 Pa·s. For example, for those with a viscosity in this range, common types on the market such as Shin-Etsu X23-7921-5 series have a relatively high viscosity, strong shear resistance, and are generally not likely to stick to the top surface of the chip but are likely to stick to tools such as scrapers. In addition, among the currently common high-viscosity semi-solid thermal pastes on the market, there are also product types with a viscosity of 500 Pa·s or above, which usually have high thermal conductivity, high anti-attenuation performance, high anti-pumping ability, etc., but show difficult-to-apply characteristics. Especially when the working surface of the pre-spreading tool in the present application has the functions such as non-stickiness or chamfer, it is bound to have a more efficient and simple spreading experience.

[0096] It should be noted that the viscosity in the present application is the test value under normal temperature and pressure.

[0097] Optionally, in the present application, the thermal paste is phase change silicone grease, or replaced by a thermal pad, or replaced by liquid metal. Optionally, the thermal pad is a phase change thermal pad or a non-phase change thermal pad, and the difference lies in whether it contains a phase change material.

[0098] The thermal paste in the present application can also be replaced by a thermal pad, such as a phase change thermal pad or a non-phase change thermal pad. The repeated rolling of the working surface can also provide high robustness for the thermal pad to adapt to existing scrapers and assembly, achieve thinning with flexibility, high frequency, and low disturbance, and enable the bottom surface of the thermal pad to be partially embedded into the micro-pits on the solid surface of the heat source to gradually expel the covered gas, thereby achieving tightness. Moreover, after the radiator is assembled and fastened and heated to soften, it can still maintain good resilience and reduce the running-in period of high and low temperature cycles. In addition, during the use of the thermal pad, pressure and temperature restrict each other. As the temperature rises, after the electronic device operates for a period of time, the thermal pad undergoes softening, creep, and stress relaxation, and the mechanical strength also decreases, and the sealing pressure decreases. Therefore, under the repeated rolling of the pre-spreading tool described in the present application, these adverse effects can be overcome to a certain extent based on the above technical effects. Preferably, the thermal pad is a phase change thermal pad. With the high and low temperature cycle operation, compared with the non-phase change thermal pad, the phase change thermal pad is more likely to undergo softening, creep, and stress relaxation, and the mechanical strength also decreases, and the sealing pressure decreases, making the technical effect of the present application more obvious.

[0099] In some embodiments of the present application, the pre-spreading tool includes: the thermal grease is a phase change silicone grease, or is replaced by a thermal pad, or is replaced by a phase change thermal pad, or is replaced by liquid metal; or, the thermal grease is a phase change silicone grease, or is replaced by a non-phase change type thermal pad, or is replaced by a phase change type thermal pad, or is replaced by liquid metal.

[0100] The thermal grease in the present application can also be replaced by liquid metal, such as gallium-based liquid metal, which has high thermal conductivity, good specific heat, low viscosity and stability. Liquid metal thermal grease is prone to dry-out phenomenon or pumping effect due to warping of the heat source surface, such as the chip surface. Therefore, it is particularly necessary to avoid the generation of bubbles. In current preparation technologies, the wettability and viscosity of liquid metal thermal grease are usually adjusted by alloying. For example, a commercially available liquid metal thermal grease mainly consists of indium (In), bismuth (Bi) and copper (Cu), has a silver-white metallic luster, has a certain viscosity and strong adhesion. These characteristics make it necessary to pay special attention to the operation method when applying liquid metal thermal grease to avoid the generation of bubbles. Under the repeated rolling action of the pre-spreading tool described in the present application, it can ensure that the bubbles are discharged as much as possible, and promote the liquid metal to overcome its own high surface tension and then press into the micro-pits on the heat source surface, so as to discharge the gas and form an anchoring effect, realizing the anti-pumping ability of the pre-spreading layer during high and low temperature cycling.

[0101] It should be noted that although liquid metal thermal grease has higher thermal conductivity than traditional silicone grease thermal paste, it also has many disadvantages such as easy leakage, too high viscosity, dependence on assembly (such as the solid surface of the contact surface, and the stiffness and clamping pressure of the fastener, etc.), unsatisfactory thermal conductivity, high price, etc. When using it, more careful selection is needed to avoid unnecessary losses. In addition, liquid metal thermal grease often has the problem of leakage. Once the liquid metal thermal grease leaks, it will cause serious damage to devices such as computers. Therefore, the use of liquid metal thermal grease requires more caution to prevent leakage during use. Some embodiments of the pre-spreading tool in the present application are aimed at improving such easy leakage (easy pumping) problems. Especially when the working surface of the pre-spreading tool in the present application has the functions of non-stickiness or chamfering, etc., it will surely have a more efficient and simple spreading experience.

[0102] In some embodiments, the pre-spreading tool of the present application is used for thermal grease with a relatively high viscosity. For example, it is used for thermal grease with a relatively high viscosity, strong shear resistance, and is not easy to stick to the top surface of the chip but is easy to stick to the scraper, such as the Shin-Etsu X23-7921-5 series. Measurements show that the silicone oil content is very low, which may be one of the reasons for its difficult application. At the same time, it may also affect its ductility and plastic filling ability. If the existing scraper is used, the application technology requirements, application efficiency and quality are low, and it is very easy to "peel off" due to easy disturbance during multiple applications, resulting in rework. Even when the disturbance is too large, it is necessary to completely clean off the thermal grease and then reapply the thermal grease on the core; while if the pre-spreading tool of the present application is used, it can reduce the skill requirements for the application technology, reduce the limitations on assembly, and can continue to roll repeatedly after reaching the required basic thickness requirement (at this time, it is easy to form disturbance when using a scraper), so as to obtain a pre-spread layer with better properties.

[0103] In some other embodiments, the pre-spreading tool of the present application is used to extend the pre-spread layer or coating layer through repeated rolling, so as to make up for the locally exposed areas on the surface of the heat source solid. For example, an appropriate amount of thermal grease can be directly applied on the surface of the heat source solid, and then the pre-spreading tool is directly used for pre-spreading, or the locally exposed areas on the surface of the heat source solid can also be extended and made up later; it can also be based on the preliminary scraping of the existing scraper, and then the pre-spreading tool is further used for pre-spreading, so as to obtain a highly flat and smooth surface and tightness that are not easily achieved by the existing scraper, etc.

[0104] In some other embodiments, the pre-spreading tool is applied to viscous type thermal grease, such as semi-solid type, optionally selected from thermal grease with high viscosity, strong shear resistance, and not easy to stick to the top surface of the chip but easy to stick to the scraper, such as the Shin-Etsu X23-7921-5 series. Using the pre-spreading tool can achieve effects such as improved anti-peeling ability, thus realizing a simple, efficient and fast paving method. However, using this straight plate method has low application efficiency and quality, and it is very easy to cause rework due to easy "peeling off" during repeated applications. Even if it is necessary to remove the thermal grease, then wipe the solid surface, such as the chip surface, with a cleaning cloth, and then squeeze out an appropriate amount of new thermal grease and repeat the application process.

[0105] In some other embodiments, the pre-spreading tool is applied to thermal greases of plastic type or semi-solid type; and / or, the working surface is subjected to special treatment and / or made of special materials to make it non-sticky to the thermal grease. The special treatment includes grinding, polishing, plating or modification, and the special materials include polytetrafluoroethylene, high-density polyethylene, nanotechnology coating, silicone coating or ceramic coating. The benefit is that the repeated rolling of the working surface can inhibit the peeling of the highly viscous plastic type or semi-solid type thermal grease, or based on the non-stick property, inhibit or avoid the sticking of the working surface to the thermal grease, thereby achieving a simpler, faster and continuous high-efficiency pre-spreading.

[0106] In addition, in some embodiments, compared with the existing scraper, the pre-spreading tool provided in the present application can make the spreading of thermal grease simpler, more efficient and faster. It can achieve simple and rapid fusion and leveling by adding multiple doses, and can well fill in the gaps (or fill in low-lying areas or local exposures such as scraping or peeling), and overcome the problem of difficult spreading of highly viscous semi-solid type thermal grease with high shear resistance, so as to reduce the requirements for both thermal conductivity and spreading difficulty in the research and development and preparation of thermal grease. For example, in some embodiments, this highly viscous semi-solid type thermal grease exhibits high thermal conductivity and high shear resistance. Compared with diluted liquid or even plastic type thermal grease, more small air cavities are likely to form in the gaps between the filler particles on the surface of the spreading layer, as well as small air cavities in the micro-pits on the solid surface covered by the bottom surface. The bottom surface needs to overcome the high shear resistance of the thermal grease itself to fully embed into the small air cavities and fully discharge the gas. However, in the research and development design, it is necessary to consider the problem that it is not easy to smear on the heat source surface that is not easy to stick, such as the exposed silicon wafer of the CPU (such as easy peeling), or it is difficult to complete high-quality smearing (such as not easy to scrape and move to obtain uniformity and flatness), while the pre-spreading tool of the present application has high robustness (such as high adaptability) to this, and can simply, quickly and efficiently obtain a pre-spread layer. In addition, for diluted liquid or plastic type thermal grease, the existing scraper also shows an unfavorable side in thinning, especially in the later stage or the finishing stage of spreading. It is necessary to worry about the sensitivity of the already relatively thin coating layer to the pressure and shear force of the scraper, and prevent wire scraping, scratching or excessive force resulting in local strip-shaped scraping. However, the cylindrical smooth working surface of the pre-spreading tool in the present application can be repeatedly rolled at a faster speed and with any hand pressure. Especially when the working surface of the pre-spreading tool in the present application has the functions of non-stick property or chamfer, etc., it will surely have a more efficient and simple spreading experience.

[0107] In this application, the rounded corners or chamfers are used to prevent wheel ruts from being pressed out on the left and right sides of the working surface during rolling. The working surface is specially treated to have non-stick properties. The non-stick layer can be more conducive to improving the efficiency and effect of repeated rolling. The special treatment includes grinding, polishing, coating, plating or modification, but has a certain viscosity that can be used for pre-spreading and adhesion-based thinning. The chamfer is linear in the longitudinal section of the working surface, as opposed to the curved shape of the rounded corner.

[0108] In this application, the working surface has a small curvature radius of not less than 2 cm or a large curvature radius of more than 2 cm. The difference between the small curvature radius and the large curvature radius is that, under the same conditions, the rolling contact area formed with the pre-spread layer is different, and thus the rolling effect will be different in some embodiments. For example, in one example, the working surface has a small curvature radius of 1.5 cm.

[0109] In this application, a housing is coupled to the outside of the working surface as a protective layer or a new working surface. For example, based on the working surface having a first surface property, a housing as a new working surface and having a second surface property can be constructed to adapt to different types of thermal paste. The housing can be, for example, sleeved around the periphery of the working surface and can be removed when needed to expose the working surface.

[0110] In this application, the working surface is specially treated to have non-stick properties. The special treatment includes grinding, polishing, coating, plating or modification, and is used to inhibit the thermal paste from sticking to the working surface during repeated rolling. After a certain number of repeated rollings, the pre-spread layer reaches the anchoring effect described in this application, realizing a relatively firm attachment of the pre-spread layer to the solid surface, and thus reducing the influence of the thermal paste sticking to the working surface. In other words, as the repeated rolling progresses, the role and importance of this non-stick function gradually decrease. It can be seen that this non-stick function plays an important role in realizing simple, efficient and rapid spreading, especially in the initial stage of pre-spreading, such as significantly reducing or overcoming the situation where the thermal paste adheres to the working surface (and is not easily adhered to the solid surface such as the top surface of the chip) in the initial stage of spreading.

[0111] Among them, the coating or plating layer. For example, the plating layer may refer to coating a thin layer of metal or plastic on the metal surface of certain articles, usually for aesthetic or storage purposes. The plating layer can be obtained by methods such as electrolysis and chemistry, forming a protective film to improve the surface properties and enhance the corrosion resistance, wear resistance and decorative properties of the articles. The coating can be formed by spraying and other means, applying a viscous liquid on the surface of the object and curing it to form a thin film, mainly for purposes such as improving surface properties, protection, insulation and decoration. In this application, the modification refers to changing the properties of a material by physical or chemical means to meet specific usage requirements, such as obtaining non-stickiness or reducing the surface energy, etc. For example, common types of modified materials include reinforcing agents, flame retardants, antistatic agents, antioxidants, etc., which can improve the strength, hardness, heat resistance and weather resistance of materials such as plastics. Compared with traditional processing methods, modification pays more attention to the improvement of comprehensive performance and functions.

[0112] In this application, the working surface or the new working surface is made of polytetrafluoroethylene, high-density polyethylene, nanotechnology coating, silicone coating or ceramic coating. This material can achieve the non-stick function described in this application. Especially for the non-stickiness of thermal paste, which is more conducive to the continuous and stable thinning of the pre-spreading layer and other effects.

[0113] Among them, polytetrafluoroethylene is a high molecular polymer obtained by polymerizing tetrafluoroethylene as a monomer, with excellent chemical stability, corrosion resistance, sealing performance, high lubrication non-stickiness, electrical insulation and good anti-aging endurance; high lubrication, it has the lowest friction coefficient among known solid materials; non-adhesion, it has the smallest surface tension among known solid materials and is almost insoluble in all solvents and does not adhere to any substance. High-density polyethylene (HDPE) has low surface energy characteristics, resulting in extremely low surface tension, and it is difficult for most substances to form a stable adhesion layer on its surface, having non-stickiness. The nanotechnology coating can significantly change the physical and chemical properties of the material surface by forming an extremely thin nanoscale film on the object surface, thereby achieving a non-stick effect. The silicone coating has non-stickiness. The main components of the silicone coating are silicone compounds, and these compounds have unique structures and properties, making the coating have non-stickiness. Silicone materials have basic properties such as low surface tension, small viscosity-temperature coefficient and high gas permeability, and these characteristics make the silicone coating perform excellently in various applications. The ceramic coating utilizes nanotechnology to make the surface compact and pore-free, thereby achieving a non-stick effect.

[0114] In this application, the working surface can also have a certain adhesiveness, which is the opposite of non - adhesiveness and is used to achieve thinning by rolling, and this thinning method is gentler. This can be an optional surface property of the working surface or the new working surface. For example, the working surface has non - adhesiveness and the new working surface has a certain adhesiveness, so as to obtain two pre - spreading methods for users to choose according to the situation and purpose.

[0115] In this application, the material of the working surface or the new working surface includes metal material, ceramic material or plastic material. Among them, metal material and ceramic material have good rigidity. Plastic material has certain elasticity and pressure affinity for solid surfaces with relatively weak strength such as the exposed silicon wafer of CPU.

[0116] In this application, the handheld part can be a handle for example. Optionally, the handheld part can have an antistatic function. Optionally, the working part, the working surface or the connecting part can all have an antistatic function.

[0117] In this application, the connecting part is used to form a movable connection between the working part and the handheld part. A movable connection refers to a connection method that allows relative movement between components. This connection method can not only transmit force or torque, but also achieve rotation or other forms of movement according to design requirements. For example, optional shaft connection, ball - socket connection, screw connection or ball - bearing connection, etc. For example, if the working surface is the circumferential outer wall surface of a roller structure, the movable connection can be coupled to the left side and / or the right side of the roller structure. If the movable connection can be coupled to the left side and the right side of the roller structure, better balance can be obtained during the repeated rolling force application process.

[0118] In this application, the heating device is used to heat the working surface to heat the thermal paste in contact during work, thereby enhancing the spreading. This heating is very beneficial for thermal pastes that are not easy to apply, such as viscous semi - solid types or phase - change types containing phase - change materials. It can pre - heat and soften the phase - change materials, which is more conducive to achieving the spreading, the pressing - in, and the smoothness and reflectivity of the top surface. Optionally, the heating device includes a heating part, which is arranged inside the circumferential surface of the cylindrical smooth working surface. This heating part generates heat by electric energy and transfers it to the surface of the working surface. Then, during the repeated rolling process, since there is no need to lift, heat can be continuously and stably transferred to the pre - spreading layer. For example, this heating part is connected to a power supply line.

[0119] Optionally, the pre-spreading tool may further include: a wiping cloth containing alcohol or lubricant, which is used to wipe the working surface. Wiping cloths of known functional types such as alcohol-containing cotton cloth pieces, microfiber cloths, lubricant-containing cotton towels, or anti-fog and anti-dust wiping cloths for glasses can be used to remove impurities, grease, etc. from the working surface, thereby making the working surface cleaner, smoother, and less sticky or non-sticky.

[0120] The above is the pre-spreading tool of the present application and its embodiments. The following are several usage methods and embodiments of the pre-spreading tool for thermal paste provided by the present application in combination with the pre-spreading tool of the present application and its embodiments.

[0121] The present application provides a usage method of a pre-spreading tool for thermal paste, which is applied to the pre-spreading tool in the first aspect. The usage method is characterized in that the usage method includes: using the pre-spreading tool to roll the thermal paste in multiple times, and setting an interval period for a certain time to volatilize a certain amount of solvent in the thermal paste, so as to obtain more favorable conditions for further spreading. In some embodiments, the more viscous the thermal paste is, the more beneficial it is for the simplicity, high efficiency, and rapid operation of the pre-spreading tool of the present application. Therefore, volatilizing a certain amount of solvent in the thermal paste is considered to be beneficial to increasing the viscosity of the thermal paste to a certain extent. This also has the effect of reducing the running-in period. In other embodiments, if the thermal paste is relatively thin, such as in a liquid type, due to the adhesive chemical force, a part of the thermal paste will adhere and be lifted on one side of the working surface when rolling away from the pre-paving layer, which is manifested as lifting silicon grease peaks (such as micro-protrusions) to a certain extent on the top surface of the pre-spreading layer. However, with the repeated rolling, or setting an interval period for a certain time to volatilize a certain amount of solvent in the thermal paste, or wiping the surface of the working surface with alcohol or lubricant before or during the use of the pre-spreading tool, this manifestation will become weaker. In addition, the non-stickiness described in the present application also has a certain inhibitory or preventive effect on this manifestation, and this manifestation becomes weaker and even disappears when the thermal paste is more viscous.

[0122] The present application also provides a method for using another thermal paste pre-spreading tool, applicable to the pre-spreading tool of the first aspect, characterized in that the method includes: wiping the surface of the working surface of the pre-spreading tool with alcohol or a lubricant before or during use. This is to enhance the ability to inhibit or prevent the thermal paste from adhering to the working surface due to its stickiness and / or to remove any adhered thermal paste. Rolling can be paused between multiple rolling cycles to wipe the working surface, indirectly achieving a certain degree of non-stickiness. For example, the working surface can be wiped before rolling, or after one or more rolling cycles. Wiping can also be used to remove impurities and / or adhered thermal paste. Because repeated rolling involves rolling friction, adhered thermal paste tends to form an extremely thin, transparent film on the working surface. However, existing scrapers use a sliding friction method, resulting in more adhered thermal paste, which tends to form thick, lumpy, and irregular bodies on the scraper surface.

[0123] The present application also provides a method for using a thermal paste pre-spreading tool, applicable to the pre-spreading tool of the first aspect, characterized in that the method includes: the working surface of the pre-spreading tool has the non-stick property, and before or during use of the pre-spreading tool, wiping the surface of the working surface of the pre-spreading tool with alcohol or a lubricant. This can be used to further inhibit or prevent the thermal paste from adhering to the working surface due to its stickiness. For example, between multiple rolling cycles, the rolling process can be paused to wipe the surface of the working surface.

[0124] In some embodiments, the pre-spreading tool and its embodiments are combined with the method of use and its embodiments.

[0125] It should be noted that, in the specification and claims of this application, the term "above" means two or more than two. The terms "include", "comprise", "have" and any variations thereof are intended to cover non-exclusive inclusions.

[0126] It should be understood that descriptions of orientation, such as up, down, front, back, top, bottom, inside, outside, side, etc. (if any), indicating orientation or positional relationships, are only for the convenience and simplification of the description of this application, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and should not be understood as a limitation on this application.

[0127] The above are only the preferred embodiments of the present application. It should be noted that for those of ordinary skill in the art, without departing from the technical principle of the present application, several improvements and modifications can be made, and these improvements and modifications should also be regarded as the protection scope of the present application; without conflict, the embodiments of the present application and the features in the embodiments can be combined with each other.

Claims

1. A pre-spreading tool for thermal paste, characterized in that, The pre-spreading tool includes: a working part having a working surface with a cylindrical smooth outer surface, the working surface being capable of forming repeated rolling to spread the thermal paste and adjust the dispersed phase structure of the thermal paste; a handheld part for holding and braking the pre-spreading tool so that the working surface forms the repeated rolling; and a connecting part for forming a movable connection between the working part and the handheld part so that the working surface forms the repeated rolling.

2. The pre-spreading tool according to claim 1, wherein It further includes: The working surface is configured to have a constant diameter throughout or a shape change in a local section, and the shape change includes a diameter change, a rounded corner or a chamfer; And / or, the working surface is treated specially to have non-stick properties, and the special treatment includes grinding, polishing, coating, plating or modification; and / or, the working surface has a small curvature radius not less than 2 cm or a large curvature radius exceeding 2 cm; and / or, a housing is coupled outside the working surface as a protective layer or a new working surface.

3. The pre-spreading tool according to claim 2, wherein, It further includes: The working surface or the new working surface is made of polytetrafluoroethylene, high-density polyethylene, a nanotechnology coating, a silicone coating or a ceramic coating; or, the working surface or the new working surface is made of a metal material, a ceramic material or a plastic material.

4. The pre-spreading tool according to any one of claims 1-3, characterized in that It further includes: The thermal paste is classified by viscosity into: a liquid type less than 3 Pa·s; or a liquid-plastic state type from 3 Pa·s to less than 20 Pa·s; or a plastic state type from 20 Pa·s to less than 200 Pa·s; or a semi-solid state type not less than 200 Pa·s.

5. The pre-spreading tool according to claim 4, characterized in that, It further includes: The thermal paste is further classified by viscosity into: a semi-solid state type not less than 360 Pa·s.

6. The pre-spreading tool according to claim 4, characterized in that, It further includes: A heating device for heating the working surface to heat the contacted thermal paste during work, thereby enhancing the pre-spreading.

7. The pre-spreading tool according to claim 6, characterized in that, It further includes: The heating device includes a heating part disposed inside the circumference of the working surface with the cylindrical smooth outer surface.

8. The pre-spreading tool according to any one of claims 1-3, characterized in that, It includes: The thermal paste is a phase change silicone grease, or is replaced by a thermal pad, or is replaced by a liquid metal.

9. The pre-spreading tool according to any one of claims 1-3, characterized in that, It further includes: A wiping cloth containing alcohol or a lubricant for cooperating to wipe the working surface.

Images