Heat-conducting gasket suitable for automatic production as well as preparation method and application of heat-conducting gasket

Abstract

The invention discloses a heat-conducting gasket suitable for automatic production and a preparation method and application thereof.The heat-conducting gasket comprises a deformable adhesive layer and an adsorption layer, the deformable adhesive layer is prepared from, by weight, 1.8-2.7 parts of double-end vinyl silicone oil, 2-3.3 parts of single-end vinyl silicone oil, 0.01-0.05 part of hydrogen-containing silicone oil, 0.2-0.5 part of silane coupling agent and 0.003-0.006 part of platinum catalyst, and the adsorption layer is prepared from, by weight, 1-3 parts of silane coupling agent, 1-3 parts of hydrogen-containing silicone oil, 1-3 parts of hydrogen-containing silicone oil, 1-3 parts of hydrogen-containing silicone oil, 1-3 parts of hydrogen-containing silicone oil, 1-3 parts of the adsorption layer is prepared from the following components in parts by weight: 40 to 60 parts of double-end vinyl silicone oil, 0.05 to 0.1 part of hydrogen-containing silicone oil, 0.003 to 0.006 part of a platinum catalyst, 0.012 to 0.024 part of an inhibitor and 40 to 60 parts of inorganic powder. The heat-conducting gasket provided by the invention has enough structural strength to bear adsorption operation of automatic equipment while keeping extremely low assembly stress.

Description

Technical Field

[0001] This invention relates to the field of electronic packaging and automated manufacturing technology, and in particular to a thermally conductive pad adapted to automated production, its preparation method, and its application. Background Technology

[0002] In modern automated production lines for electronic products, thermal pads are critical thermal interface materials (TIMs), and the reliability and efficiency of their automated pick-and-place process are paramount. Automated equipment typically uses vacuum nozzles to pick up thermal pads, precisely position them, and attach them between heat-generating components (such as CPUs, GPUs, and power ICs) and the heat dissipation structure.

[0003] To balance heat dissipation and device protection, thermal pads are often designed with low hardness (Shore 00 hardness as low as below 30) and low modulus to minimize assembly stress and prevent mechanical damage to fragile chips, solder joints, or PCBs. However, this ultra-soft, low-stress design presents a serious technical dilemma: the ultra-low hardness pad material itself has low structural strength, poor tear resistance, and is easily deformed. When assembled on automated production lines, the suction force applied by the vacuum nozzle often causes excessive stretching and indentation in soft areas, and edges or thin-walled areas may even be sucked through. Furthermore, during high-speed pick-and-place processes, the pads are also highly susceptible to tearing, breakage, curling, or permanent deformation due to mechanical stress, leading to placement failures, debris contamination, or affecting the final heat dissipation effect. This not only reduces production yield but also increases production costs and downtime risks. Existing technologies have increased the hardness of thermal pads to meet automated suction requirements, but this increase in hardness is accompanied by an increase in stress, which still cannot meet the needs of device protection.

[0004] Therefore, there is an urgent need to develop a thermally conductive pad that can adapt to automated production, while maintaining extremely low assembly stress and having sufficient structural strength to withstand the adsorption operation of automated equipment and not easily damaged, so as to facilitate efficient production. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention proposes a thermally conductive pad suitable for automated production, its preparation method, and its application.

[0006] This invention provides a thermally conductive pad suitable for automated production, comprising a deformable adhesive layer and an absorbent layer. The deformable adhesive layer, by weight, comprises the following components: 1.8-2.7 parts of double-ended vinyl silicone oil (e.g., 1.8, 2.0, 2.2, 2.4, 2.6, 2.7 parts); 2-3.3 parts of single-ended vinyl silicone oil (e.g., 2, 2.2, 2.4, 2.6, 2.8, 3, 3.2, 3.3 parts); 0.01-0.05 parts of hydrogen-containing silicone oil (e.g., 0.01, 0.02, 0.03, 0.04, 0.05 parts); and silicone... Alkane coupling agent 0.2-0.5 parts, such as 0.2, 0.3, 0.4, 0.5 parts; platinum catalyst 0.003-0.006 parts, such as 0.003, 0.004, 0.005, 0.006 parts; inhibitor 0.012-0.024 parts, such as 0.012, 0.014, 0.016, 0.018, 0.02, 0.022, 0.024 parts; thermally conductive powder 72-112 parts, such as 72, 75, 80, 85, 90, 95, 100, 105, 110, 112 parts; The adsorption layer comprises, by weight, the following components: 40-60 parts of double-ended vinyl silicone oil (e.g., 40, 45, 50, 55, 60 parts); 0.05-0.1 parts of hydrogen-containing silicone oil (e.g., 0.05, 0.06, 0.07, 0.08, 0.09, 1 part); 0.003-0.006 parts of platinum catalyst (e.g., 0.003, 0.004, 0.005, 0.006 parts); 0.012-0.024 parts of inhibitor (e.g., 0.012, 0.014, 0.015, 0.018, 0.02, 0.04 parts); and 40-60 parts of inorganic powder (e.g., 40, 45, 50, 55, 60 parts).

[0007] This invention utilizes a formulation design of a deformable adhesive layer and an adsorption layer to create a thermally conductive pad that maintains extremely low assembly stress while possessing sufficient structural strength to withstand the adsorption operations of automated equipment and is not easily damaged. The adsorption layer primarily reinforces the thermally conductive pad by adding submicron-sized fillers. Furthermore, the adsorption layer and the deformable adhesive layer interact to form a unified whole (by using a wire rod to coat the adsorption layer material, "grooves" of a certain depth appear on the surface of the deformable adhesive layer; the adsorption layer material flows into these "grooves," where it fuses and vulcanizes with the vinyl silicone oil in the deformable adhesive layer at high temperatures). This invention combines two formulations: the internal deformable portion employs a three-dimensional network structure with fewer long molecular chains; the main body uses chain extension to increase cohesion and entanglement to improve hardness while maintaining appropriate stress; and a reinforcing layer of a certain thickness is coated on the surface of the deformable adhesive layer as an adsorption layer to simultaneously satisfy mechanical and adsorption stability.

[0008] Furthermore, the thermally conductive powder includes aluminum oxide or zinc oxide with a particle size D50 of 0.3-1 μm, aluminum oxide or aluminum nitride with a particle size D50 of 1.5-3 μm, aluminum oxide or aluminum nitride with a particle size D50 of 6-15 μm, and aluminum oxide or aluminum nitride with a particle size D50 of 70-150 μm.

[0009] Furthermore, the inorganic powder is any one or more of silicon dioxide, aluminum oxide, aluminum nitride, or zinc oxide.

[0010] Furthermore, the particle size D50 of the inorganic powder is 0.2-0.8 μm. If the particle size is too large, it will lead to an excessive surface thickness during coating, which may result in instability. In addition, large inorganic powder particles will increase the interfacial thermal resistance under high cross-linking. Furthermore, the thickness of the adsorption layer is 20-40 μm. If the adsorption layer thickness is too low, the overall thermal pad will be unable to meet the requirements for automated adsorption stability. Within a specific range, the adsorption layer thickness can reduce the impact on thermal resistance while meeting adsorption stability requirements. Specifically, when the thickness is 20-40 μm (the surface adhesive layer thickness is 10-30 μm), the impact on thermal resistance is within 30%, and stable adsorption is maintained. The following provides a method for coating the adsorption layer: When the thickness is controlled at 20-40 μm, a 5-10 μm wire rod can be used to coat the surface of the deformable adhesive layer with the adsorption layer material. The wire rod will scrape 5-10 μm lines on the surface of the deformable adhesive layer, allowing the adsorption layer material to flow into the gaps, thus achieving a bonding between the two. This results in a 10-30 μm reinforcing layer on the surface for automated adsorption. The hardness of this reinforcing layer reaches Shore A60-80, and the wire rod thickness does not exceed 10 μm to ensure that the overall thickness of the surface layer does not exceed 30 μm. Furthermore, the viscosity of the dual-end vinyl silicone oil and the single-end vinyl silicone oil in the deformable adhesive layer is 500-2000 cps.

[0011] Furthermore, the viscosity of the double-ended vinyl silicone oil in the adsorption layer is 2000-5000 cps.

[0012] The present invention also provides a method for preparing the aforementioned thermally conductive pad, comprising the following steps: Weigh out and add double-ended vinyl silicone oil, single-ended vinyl silicone oil, hydrogen-containing silicone oil and inhibitor according to the weight parts, and disperse for 5-10 minutes. Then weigh out and add platinum catalyst and silane coupling agent according to the weight parts and disperse evenly to obtain matrix liquid. Add the base liquid and 0.3-1 μm thermally conductive powder to a mixing bowl and mix under vacuum until homogeneous. Then add 1-3 μm thermally conductive powder and mix under vacuum. Weigh out half of the 70-150 μm thermally conductive powder by weight and continue mixing under vacuum. Add 7-15 μm thermally conductive powder and mix under vacuum. Add the remaining half of the 70-150 μm thermally conductive powder and mix under vacuum until homogeneous. Continue mixing the homogeneous adhesive under vacuum for 80 minutes. Continued vacuum mixing can make the adhesive more dense and free of bubbles. The mixed rubber is pressed into a block, and the block is calendered to a specified thickness using a calender. After baking, it is vulcanized to obtain a deformable rubber layer. The materials of Formula 2 were weighed and mixed according to the weight parts, and then dispersed to obtain the adsorption layer material; The thermal pad is obtained by coating the adsorption layer material onto the surface of the deformable adhesive layer and then baking it.

[0013] The present invention also provides the application of the thermally conductive pad in electronic appliances and new energy vehicles, and uses automated equipment to assemble the thermally conductive pad.

[0014] Furthermore, the thermally conductive pad can be used for adsorption applications at 0.04-0.08 MPa.

[0015] In summary, compared with the prior art, the present invention achieves the following technical effects: (1) The thermally conductive pad provided by the present invention can simultaneously meet the requirements of low stress and adsorption stability, and can adapt to automated production; (2) The thermal pad provided by the present invention also has high thermal conductivity. Attached Figure Description

[0016] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the thermally conductive pad structure obtained in Embodiment 1 of the present invention; 1-Deformable adhesive layer, 2-Adsorption layer. Detailed Implementation

[0018] To enable those skilled in the art to better understand the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0019] Example The present invention will be further illustrated below with reference to specific embodiments and comparative embodiments. The following specific embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the following embodiments, and are not in particular limited to the types of raw materials used in the following specific embodiments.

[0020] I. The sources of raw materials for the examples and comparative examples are as follows: Unless otherwise specified, all raw materials used in the embodiments and comparative examples of this invention are commercially available.

[0021] II. Performance Testing Methods (1) Hardness test: The test was conducted according to the ASTM D2240 standard, and the hardness of the deformable adhesive layer was tested. (2) Thermal conductivity test: The test shall be conducted in accordance with the standard of ASTM D5470; (3) Height limit thermal resistance test: The test shall be conducted in accordance with the ASTM D5470 standard; (4) Mechanical property testing: Tested in accordance with ASTM D575 standard; (5) Adsorption effect test: The adsorption level at a pressure of 0.08 MPa is judged as follows:

[0022] Example 1 The thermally conductive pad of Example 1 includes a deformable adhesive layer and an absorbent layer: The deformable adhesive layer comprises the following components by weight: 2.1 parts of double-ended vinyl silicone oil with a viscosity of 500 cps, 2.9 parts of single-ended vinyl silicone oil with a viscosity of 2000 cps, 0.02 parts of hydrogen-containing silicone oil, 0.3 parts of silane coupling agent, 0.003 parts of platinum catalyst, 0.012 parts of inhibitor, 9.4 parts of zinc oxide with a particle size D50 of 0.6 μm, 18 parts of aluminum oxide with a particle size D50 of 2 μm, 25.285 parts of aluminum oxide with a particle size D50 of 10 μm, and 42 parts of aluminum nitride with a particle size D50 of 100 μm. The adsorption layer, by weight, comprises the following components: 45 parts of dual-terminated vinyl silicone oil with a viscosity of 3000 cps, 0.04 parts of hydrogen-containing silicone oil, 0.003 parts of platinum catalyst, 0.012 parts of inhibitor, 54.945 parts of aluminum nitride with a particle size D50 of 0.5 μm, and an adsorption layer thickness of 20-30 μm.

[0023] Example 2 The difference between Example 2 and Example 1 is that the thickness of the adsorption layer is 40-50 μm.

[0024] Example 3 The difference between Example 3 and Example 1 is that the coating thickness is <10 μm.

[0025] Comparative Example 1 The thermal pad of Comparative Example 1, by weight, comprises the following components: 2.1 parts of double-ended vinyl silicone oil with a viscosity of 500 cps, 2.9 parts of single-ended vinyl silicone oil with a viscosity of 2000 cps, 0.02 parts of hydrogen-containing silicone oil, 0.3 parts of silane coupling agent, 0.003 parts of platinum catalyst, 0.012 parts of inhibitor, 9.4 parts of zinc oxide with a particle size D50 of 0.6 μm, 18 parts of aluminum oxide with a particle size D50 of 2 μm, 25.265 parts of aluminum oxide with a particle size D50 of 10 μm, and 42 parts of aluminum nitride with a particle size D50 of 100 μm.

[0026] Comparative Example 2 The thermal pad of Comparative Example 2, by weight, comprises the following components: 2.1 parts of double-ended vinyl silicone oil with a viscosity of 500 cps, 2.9 parts of single-ended vinyl silicone oil with a viscosity of 2000 cps, 0.04 parts of hydrogen-containing silicone oil, 0.3 parts of silane coupling agent, 0.003 parts of platinum catalyst, 0.012 parts of inhibitor, 9.4 parts of zinc oxide with a particle size D50 of 0.6 μm, 18 parts of aluminum oxide with a particle size D50 of 2 μm, 25.265 parts of aluminum oxide with a particle size D50 of 10 μm, and 42 parts of aluminum nitride with a particle size D50 of 100 μm.

[0027] Table 1. Results of Examples and Comparative Examples

[0028] The thermally conductive pads in Examples 1-3 contain both a deformable adhesive layer and an adsorption layer. The resulting thermally conductive pads all exhibit high thermal conductivity while maintaining adsorption stability under low stress, thus meeting the requirements for automated production. In contrast, the thermally conductive pads in Comparative Examples 1-2 do not contain an adsorption layer. Therefore, the resulting thermally conductive pads cannot simultaneously achieve low stress and adsorption stability to adapt to automated production; a balance between these two aspects cannot be achieved.

[0029] Based on the test data in Table 1 regarding the thermal conductivity, hardness, maximum resistance, and adsorption effect of the thermal pads, the thermal pads prepared through Examples 1-3 have significant advantages over the comparative examples and can effectively meet the high standards required by customers and the market.

[0030] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A thermally conductive pad suitable for automated production, characterized in that, It includes a deformable adhesive layer and an absorbent layer, wherein the deformable adhesive layer comprises, by weight, the following components: 1.8-2.7 parts of double-ended vinyl silicone oil 2-3.3 parts of single-ended vinyl silicone oil Hydrogen-containing silicone oil 0.01-0.05 parts 0.2-0.5 parts of silane coupling agent Platinum catalyst 0.003-0.006 parts Inhibitor 0.012-0.024 parts 72-112 parts of thermally conductive powder; The adsorption layer comprises the following components by weight: 40-60 parts of double-ended vinyl silicone oil Hydrogen-containing silicone oil 0.05-0.1 parts Platinum catalyst 0.003-0.006 parts Inhibitor 0.012-0.024 parts 40-60 parts of inorganic powder.

2. The thermally conductive pad according to claim 1, characterized in that, The thermally conductive powder includes aluminum oxide or zinc oxide with a particle size D50 of 0.3-1 μm, aluminum oxide or aluminum nitride with a particle size D50 of 1.5-3 μm, aluminum oxide or aluminum nitride with a particle size D50 of 6-15 μm, and aluminum oxide or aluminum nitride with a particle size D50 of 70-150 μm.

3. The thermally conductive pad according to claim 1, characterized in that, The inorganic powder is any one or more of silicon dioxide, aluminum oxide, aluminum nitride, or zinc oxide.

4. The thermally conductive pad according to claim 3, characterized in that, The particle size D50 of the inorganic powder is 0.2-0.8 μm.

5. The thermally conductive pad according to claim 1, characterized in that, The thickness of the adsorption layer is 20-40 μm.

6. The thermally conductive pad according to claim 1, characterized in that, The viscosity of the double-ended vinyl silicone oil and the single-ended vinyl silicone oil in the deformable adhesive layer is 500-2000 cps.

7. The thermally conductive pad according to claim 1, characterized in that, The viscosity of the double-ended vinyl silicone oil in the adsorption layer is 2000-5000 cps.

8. The method for preparing the thermally conductive pad according to any one of claims 1-7, characterized in that, Includes the following steps: Weigh out and add double-ended vinyl silicone oil, single-ended vinyl silicone oil, hydrogen-containing silicone oil and inhibitor according to the weight parts, and disperse for 5-10 minutes. Then weigh out and add platinum catalyst and silane coupling agent according to the weight parts and disperse evenly to obtain matrix liquid. Add the matrix liquid and 0.3-1 μm thermally conductive powder to a mixing bowl and mix under vacuum until homogeneous. Then add 1-3 μm thermally conductive powder and mix under vacuum. Weigh out half of the 70-150 μm thermally conductive powder by weight and continue mixing under vacuum. Add 7-15 μm thermally conductive powder and mix under vacuum. Add the remaining half of the 70-150 μm thermally conductive powder and mix under vacuum until homogeneous. Continue mixing the homogeneous gel under vacuum for 80 minutes. The mixed rubber is pressed into a block, and the block is calendered to a specified thickness using a calender. After baking, it is vulcanized to obtain a deformable rubber layer. Weigh and mix the materials of Formula 2 according to the weight parts, and disperse them to obtain the adsorption layer material; The thermal pad is obtained by coating the adsorption layer material onto the surface of the deformable adhesive layer and then baking it.

9. The application of the thermally conductive pad according to any one of claims 1-7 in electronic appliances and new energy vehicles, characterized in that, Automated equipment is used to assemble the thermal pads.

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