Two-component heat-conducting gel and preparation method thereof

Abstract

The invention relates to a two-component heat-conducting gel and a preparation method thereof. The heat-conducting gel is formed by mixing and curing a component A and a component B according to a certain proportion, wherein the component A consists of the following components in parts by weight: 13-39 parts of compound vinyl silicone oil A, 0.018-0.06 part of an accelerant and 67-420 parts of heat-conducting filler; the component B is prepared from 0 to 20 parts of vinyl silicone oil B, 1 to 32 parts of hydrogen-containing silicone oil, 0.036 to 0.12 part of chain extender and 67 to 420 parts of heat-conducting filler. The component A and the component B are respectively packaged, and are fully mixed according to a certain proportion during use, and the mixture is cured at normal temperature for 2 hours, so that the high-performance double-component heat-conducting gel with high heat conductivity coefficient, low hardness and flexibility, low density and proper potting viscosity can be prepared.

Description

Technical Field

[0001] The present invention relates to the technical field of thermal conductive gels, and in particular to a two-component thermal conductive gel and a preparation method thereof. Background Art

[0002] In recent years, the performance of electronic components has leapt forward, chip power has climbed, and the heat dissipation requirements of emerging technology scenarios such as 3D packaging technology, 5G communications, electric vehicles and fast charging technology have become increasingly higher.

[0003] Thermal interface materials mainly include thermal adhesives, phase change thermal conductive materials, thermal pastes and solders. Thermal conductive gel is a high-performance thermal interface material, usually used between heat-conducting and heat-dissipating components to reduce the contact resistance of the interface. The surfaces of components are mostly irregular and not smooth, and bubbles and gaps will exist during the assembly contact process, with the actual contact area being less than 2%. The interface resistance is mainly affected by the thermal conductivity of the thermal interface material, the thickness of the bonding area and the thermal conductivity of the thermal interface material. Thermal conductive gel can fully cover the space between the two components, maintaining a low thickness, reducing the contact resistance between the two interfaces and increasing the heat conduction efficiency.

[0004] Common issues with thermally conductive gels include low thermal conductivity, long curing times or high curing temperatures, and reduced bonding and mechanical properties due to high filler loading, ultimately impacting process production and product stability. Two-component thermally conductive gels, in particular, exhibit high viscosity, making them unsuitable for potting, and are difficult to remove from electronic products, making them impossible to repair. Summary of the Invention

[0005] The purpose of the present invention is to solve the above-mentioned deficiencies in the prior art, thereby providing a stable two-component thermally conductive gel with high thermal conductivity and low density.

[0006] Another object of the present invention is to provide a method for preparing a two-component thermally conductive gel.

[0007] A two-component thermal conductive gel is prepared by mixing component A and component B;

[0008] The component A comprises the following components in parts by weight:

[0009] Compound vinyl silicone oil A 13-39 parts

[0010] Thermal conductive powder 67-420 parts

[0011] Accelerator 0.018-0.06 parts

[0012] Component B includes the following components in parts by weight:

[0013] Vinyl silicone oil B 0-20 parts

[0014] 1-32 parts of hydrogenated silicone oil

[0015] Thermal conductive powder 67-420 parts

[0016] Chain extender 0.036-0.12 parts.

[0017] The mass ratio of component A to component B is 1:0.9-1.2.

[0018] The compound vinyl silicone oil A is prepared by mixing two vinyl silicone oils with a vinyl content of 0.3-10wt% and a vinyl content of 0.5-1.0wt%. The mixing ratio of the two vinyl silicone oils with a vinyl content of 0.3-10wt% and a vinyl content of 0.5-1.0wt% is 0.2-5.5. The viscosity of the vinyl silicone oil with a vinyl content of 0.3-10wt% is 100 mPa·s-16000 mPa·s.

[0019] The viscosity of hydrogen silicone oil is 50-500mPa.s;

[0020] Hydrogenated silicone oil is used as a crosslinking agent to crosslink with the vinyl silicone oil in components A and B. The dosage of hydrogenated silicone oil is calculated as follows:

[0021] M H =﹙M Vi ×A×Vi%﹚ / ﹙H%×27﹚

[0022] Where: M H is the mass of hydrogen silicone oil; M Vi is the mass of vinyl silicone oil; A is n(Si-H) / n(Si-Vi), that is, the molar ratio of active hydrogen in hydrogen-containing silicone oil to vinyl in all vinyl silicone oils in components A and B; Vi% is the mass fraction of vinyl in all vinyl silicone oils in components A and B; H% is the mass fraction of hydrogen in hydrogen-containing silicone oil; 27 is the molar mass of vinyl, and the mass fraction of active hydrogen in hydrogen-containing silicone oil is 0.05-0.2%.

[0023] The viscosity of the vinyl silicone oil B is 5000 mPa·s-16000 mPa·s.

[0024] The promoter is selected from Group VIII transition metals and their compounds or complexes.

[0025] The promoter is a poisoning-resistant platinum catalyst.

[0026] The thermal conductive powder is a spherical metal powder surface-treated with a silane coupling agent. The metal powder is one or a mixture of metal hydroxides, metal oxides, and metal nitrides. The median diameter D50 of the thermal conductive powder is 10-50 μm.

[0027] The chain extender is used to adjust and control the speed of vulcanization, and is an acetylene compound, a dibasic acid ester containing a double bond, or a nitrogen-containing compound.

[0028] The preparation method of the two-component thermal conductive gel comprises the following steps:

[0029] By weight, 13-39 parts of compound vinyl silicone oil A and 0.018-0.06 parts of accelerator are added to a stirring device and stirred for 20-25 minutes. Then, 67-420 parts of thermal conductive powder are added to the stirring device in multiple times, each time with an interval of 10-15 minutes and stirred until there is no dry powder, no agglomeration, no obvious graininess or streaks. After the thermal conductive powder is added in batches, continue stirring and vacuum for 30-35 minutes to obtain component A;

[0030] By weight, 0-20 parts of vinyl silicone oil B, 1-32 parts of hydrogenated silicone oil, and 0.036-0.12 parts of chain extender are added to a stirring device and stirred for 20-25 minutes. Then, 67-420 parts of thermal conductive powder are added to the stirring device in multiple times, each time with an interval of 10-15 minutes, and stirred until there is no dry powder, no agglomeration, no obvious graininess or streaks. After the thermal conductive powder is added in batches, continue stirring and vacuum for 30-35 minutes to obtain component B;

[0031] Component A and component B are mixed evenly in proportion to obtain a two-component gel.

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] ① This invention uses metal powders with varying particle size distributions and surface-treated with silane coupling agents as thermally conductive fillers to enhance thermal conductivity. For high-thermal-conductivity thermal powders, an appropriate oil-to-powder ratio is adjusted, and a low-viscosity compounded vinyl silicone oil is selected. This oil can be mixed with as much thermally conductive powder as possible to ensure excellent extrusion performance while maintaining high thermal conductivity.

[0034] Explore the appropriate silicon-hydrogen ratio so that components A and B can be mixed to form a plastic body (similar to plasticine), which can compress the thickness of the thermal conductive gel to the extreme and fully adhere to the irregular surface of the component, thereby increasing the thermal conductivity without affecting the disassembly of the component.

[0035] The finished product has high thermal conductivity while maintaining low hardness and flexibility, low density and suitable potting viscosity to meet product requirements.

[0036] In component B, the optimal ratio of higher viscosity vinyl silicone oil and low viscosity hydrogen silicone oil is explored. This not only increases the flexibility of the thermal conductive gel and ensures the reworkability of the thermal conductive gel on components, but also matches the viscosity of component A, reducing the viscosity difference between components A and B, making it suitable for large-scale production. DETAILED DESCRIPTION

[0037] The two-component thermal conductive gel of the present invention is formed by mixing and curing components A and B in a certain proportion. Component A consists of 13-39 parts by weight of compound vinyl silicone oil A, 0.018-0.06 parts of accelerator, and 67-420 parts of thermal conductive filler; component B consists of 0-20 parts of vinyl silicone oil B, 1-32 parts of hydrogenated silicone oil, 0.036-0.12 parts of chain extender, and 67-420 parts of thermal conductive filler.

[0038] The end-compounded vinyl silicone oil A is a mixture of two vinyl silicone oils with a vinyl content of 0.3-10wt% and a vinyl content of 0.5-1.0wt%, preferably with m(SiVi 0.3) / m(SiVi 0.7) of 0.2-5.5 and a viscosity of 100 mPa·s-16000 mPa·s. The present invention introduces a certain proportion of 0.3wt% vinyl silicone oil with a large molecular weight of vinyl content, and the corresponding molecular chain can fully wrap the filler particles, making it difficult for the filler to settle and having strong stability, increased strength and toughness, while the mixed silica gel can ensure a lower viscosity and is easier to mix with thermal conductive powder. The thermal conductive gel can be better extruded while having excellent thermal conductivity and maintained at a lower density.

[0039] The viscosity of the hydrogen-containing silicone oil is 50-500mPa.s, and the hydrogen content is 0.05-0.2wt%, preferably 0.08-1.80wt%. Its hydrogen content plays a key role in the mechanical properties of the encapsulation glue. Too high a hydrogen content will lead to an excessively high local cross-linking density, and the thermally conductive gel after vulcanization will be too brittle and its deformation resistance will be weakened. Too low a hydrogen content will lead to incomplete curing, and bubbles will be generated during the curing process, thereby causing strength degradation. The present invention selects a suitable hydrogen content so that the thermally conductive gel can be fully fitted to the irregular surface of components with a minimum thickness (0.05mm), reducing the resistance of the contact interface and enhancing the heat conduction capacity. Hydrogen-containing silicone oil is used as a cross-linking agent for cross-linking with the vinyl silicone oil in component A and component B. The dosage calculation formula of the cross-linking agent is:

[0040] M H =﹙M Vi ×A×Vi%﹚ / ﹙H%×27﹚

[0041] The viscosity of the vinyl silicone oil B is 5000-16000 mPa.s. This invention selects a certain proportion of higher-viscosity vinyl silicone oil B for use in component B, combined with a low-viscosity hydrogenated silicone oil. The proportion of vinyl silicone oil B in component B can be adjusted based on the viscosity of component A to achieve viscosity matching. This ensures smooth extrusion of components A and B during the production process and ensures a thorough mixing of the two components at a 1:1 mass ratio, making it suitable for large-scale production and providing suitable potting conditions.

[0042] The promoter is selected from Group VIII transition metals and their compounds or complexes, preferably a poisoning-resistant platinum catalyst.

[0043] The thermally conductive filler is a spherical surface-treated aluminum oxide, aluminum hydroxide, aluminum nitride or boron nitride, or a mixture of several thereof. The thermal conductivity of the thermally conductive gel is mainly determined by factors such as the thermal conductivity of the thermally conductive filler itself and the distribution degree of the filler in the base gel. The present invention selects aluminum hydroxide or aluminum oxide particles with different particle size distributions and surface treatment with silane coupling agents as the main component as fillers. The different particle size distributions allow small-sized particles to fill the polyhedron gaps formed by large particles, presenting a metal-like lattice morphology, forming a thermally conductive grid. The median diameter D50 of the thermally conductive powder is 10-50 μm, preferably 7-45 μm.

[0044] The linking agent may be an acetylene compound, which can coordinate with the platinum atoms in the catalyst at room temperature to prevent SiVi and Si-H from participating in the reaction at the same time. In the present invention, ethynyl cyclohexanol is preferred.

[0045] The present invention can be implemented by the following steps:

[0046] By weight, 13-39 parts of compound vinyl silicone oil A and 0.018-0.06 parts of accelerator are added to a stirring device and stirred for 20-25 minutes. Then, 67-420 parts of thermal conductive powder are added to the stirring device in multiple times, each time with an interval of 10-15 minutes and stirred until there is no dry powder, no agglomeration, no obvious graininess or streaks. After the thermal conductive powder is added in batches, continue stirring and vacuum for 30-35 minutes to obtain component A;

[0047] By weight, 0-20 parts of vinyl silicone oil B, 1-32 parts of hydrogenated silicone oil, and 0.036-0.12 parts of chain extender are added to a stirring device and stirred for 20-25 minutes. Then, 67-420 parts of thermal conductive powder are added to the stirring device in multiple times, each time with an interval of 10-15 minutes, and stirred until there is no dry powder, no agglomeration, no obvious graininess or streaks. After the thermal conductive powder is added in batches, continue stirring and vacuum for 30-35 minutes to obtain component B;

[0048] Component A and component B are mixed evenly in proportion to obtain a two-component gel.

[0049] The following examples are intended to better illustrate the effects of the present invention, but the present invention is not limited to the examples.

[0050] Example 1:

[0051] The present invention provides a two-component thermally conductive gel, wherein the composition is divided into two components A and B and is independently packaged. The composition is prepared by the following steps:

[0052] Component A: Add 11kg of vinyl-terminated silicone oil with a vinyl content of 0.30%, 2kg of vinyl-terminated silicone oil with a vinyl content of 0.70%, and 0.018kg of anti-poisoning platinum catalyst into a double planetary mixing equipment and stir for 20 minutes. Then add 67kg of thermal conductive powder with D50 of 12μm spherical aluminum hydroxide as the main component in batches. Stir each time until there is no dry powder, no agglomeration, no obvious graininess or streaks. After adding, continue stirring and vacuum for 30 minutes.

[0053] Component B: Add 11kg of end-side hydrogenated silicone oil with an active hydrogen content of 0.08%, 1.8kg of vinyl silicone oil B, and 0.036kg of ethynyl cyclohexanol into a double planetary mixing device and stir for 20 minutes. Then add 67kg of thermal conductive powder with D50 of 12μm spherical aluminum hydroxide as the main component in batches. Stir each time until there is no dry powder, no agglomeration, and no obvious graininess or streaks. After adding, continue stirring and vacuum for 30 minutes.

[0054] Example 2: Component A: 18 kg of vinyl-terminated silicone oil with a vinyl content of 0.70%, 3 kg of ethylene-terminated silicone oil with a vinyl content of 0.30%, and 0.06 kg of anti-poisoning platinum catalyst were added to a dual planetary stirring apparatus and stirred for 23 minutes. Then, 300 kg of thermal conductive powder with a D50 of 12 μm spherical alumina as the main component was added in batches. Stirring was performed each time until there was no dry powder, no agglomerates, and no obvious graininess or streaks. After the addition was completed, stirring was continued and vacuum was applied for 33 minutes.

[0055] Component B: Add 20kg of vinyl-terminated silicone oil with a vinyl content of 0.30%, 1.12kg of end-side hydrogen-containing silicone oil with an active hydrogen content of 0.18%, and 0.12kg of ethynyl cyclohexanol into a double planetary mixing equipment and stir for 20 minutes. Then add 300kg of thermal conductive powder with a D50 of 12μm spherical alumina as the main component in batches. Stir each time until there is no dry powder, no agglomeration, and no obvious graininess or streaks. After adding, continue stirring and vacuum for 30 minutes.

[0056] Example 3:

[0057] Component A: Add 22 kg of compounded vinyl-terminated silicone oil A with a viscosity of 100 mPa.s and 0.036 kg of anti-poisoning platinum catalyst into a double planetary mixing equipment and stir for 25 minutes. Then add 420 kg of thermal conductive powder with D50 of 30 μm spherical alumina as the main component in batches. Stir each time until there is no dry powder, no agglomeration, no obvious graininess or streaks. After adding, continue stirring and vacuum for 35 minutes.

[0058] Component B: Add 20kg of end-side hydrogen-containing silicone oil with an active hydrogen content of 0.18%, 2kg of 100 mPa.s vinyl-terminated silicone oil, and 0.072kg of ethynylcyclohexanol into a double planetary reactor and stir for 20 minutes. Then add 420kg of thermal conductive powder with D50 of 30μm spherical alumina as the main component in batches. Stir each time until there is no dry powder, no agglomeration, and no obvious graininess or streaks. After adding, continue stirring and vacuum for 35 minutes.

[0059] Example 4:

[0060] Component A: Add 32 kg of 0.3% vinyl-terminated silicone oil, 7 kg of 0.7% vinyl-terminated silicone oil, and 0.054 kg of anti-poisoning platinum catalyst into a double planetary mixing equipment and stir for 20 minutes. Then add 228 kg of thermal conductive powder with D50 of 12 μm spherical aluminum hydroxide as the main component in batches. Stir each time until there is no dry powder, no agglomeration, no obvious granularity or streaks. After adding, continue stirring and vacuum for 30 minutes.

[0061] Component B: Add 32kg of end-side hydrogen-containing silicone oil with an active hydrogen content of 0.08%, 5.4kg of vinyl silicone oil B, and 0.108kg of ethynyl cyclohexanol into the double planetary reactor and stir for 20 minutes. Then add 228kg of thermal conductive powder with 12μm spherical aluminum hydroxide as the main component in batches. Stir each time until there is no dry powder, no agglomeration, and no obvious graininess or streaks. After adding, continue stirring and vacuum for 30 minutes.

[0062] Compare column 1:

[0063] Component A: Add 13 kg of compound vinyl silicone oil A and 0.018 kg of anti-poisoning platinum catalyst into the double planetary reactor and stir for 20 minutes. Then add 67 kg of filler with a D50 of 12 μm spherical aluminum hydroxide as the main component in batches, stir and vacuum for 30 minutes.

[0064] Component B: Add 12 kg of end-side hydrogenated silicone oil with an active hydrogen content of 0.08%, 1.3 kg of vinyl silicone oil B, and 0.036 kg of ethynyl cyclohexanol into a double planetary reactor and stir for 20 minutes. Then add 67 kg of filler with a D50 of 12 μm spherical aluminum hydroxide as the main component in batches, stir, and evacuate for 30 minutes.

[0065] Comparative Example 2:

[0066] Component A: Add 13 kg of compound vinyl silicone oil A and 0.018 kg of anti-poisoning platinum catalyst into the double planetary reactor and stir for 20 minutes. Then add 76 kg of filler with a D50 of 12 μm spherical aluminum hydroxide as the main component in batches, stir and vacuum for 30 minutes.

[0067] Component B: 13 kg of end-side hydrogenated silicone oil with an active hydrogen content of 0.08% and 0.036 kg of ethynylcyclohexanol were added to a double planetary mixer and stirred for 20 minutes. Then, 76 kg of filler composed mainly of spherical aluminum hydroxide with a D50 of 12 μm was added in batches, stirred, and vacuumed for 30 minutes.

[0068] Performance testing:

[0069] Thermal conductivity: tested using the TPS 2500S thermal conductivity tester from Hot Disk.

[0070] Extrusion rate: The thermal conductive gel was loaded into a 30cc EFD dispensing syringe with a 0.100 needle and tested using a handheld dispensing device at 90 psi.

[0071] Density: Tested according to GB / T 533-2008

[0072] Viscosity: Tested using Brookfield viscometer 14# rotor

[0073] The above test specifications were used to test Examples 1-4 and Comparative Examples 1-2. The test results are shown in Table 1.

[0074] Table 1

[0075]

[0076] As can be seen from Table 1, compared with Example 1, Examples 2 and 3, in which the thermal conductive powder fillers are replaced with fillers whose main components are spherical alumina with a D50 of 12 μm and fillers whose main components are spherical alumina with a D50 of 30 μm, respectively, exhibit better thermal conductivity. In Example 4, the appropriate increase in the oil-to-powder ratio can increase the thermal conductivity. While Example 1 has better extrusion performance than Comparative Example 1, the viscosity difference between components A and B is smaller. In Comparative Example 2, component B does not have high-viscosity vinyl silicone oil added, and there will be residue when it is removed. Compared with Comparative Example 2, Example 4 appropriately increases the proportion of high-viscosity vinyl silicone oil in component B, exhibiting better extrusion performance and a smaller viscosity difference between components A and B.

Claims

1. A two-component thermally conductive gel, characterized by: Prepared by mixing component A and component B; The component A comprises the following components in parts by weight: Compound vinyl silicone oil A 13-39 parts Thermal conductive powder 67-420 parts Accelerator 0.018-0.06 parts Component B includes the following components in parts by weight: Vinyl silicone oil B 0-20 parts 1-32 parts of hydrogenated silicone oil Thermal conductive powder 67-420 parts Chain extender 0.036-0.12 parts.

2. The two-component thermally conductive gel according to claim 1, characterized in that: The mass ratio of component A to component B is 1:0.9-1.

2.

3. The two-component thermally conductive gel according to claim 1, characterized in that: The compound vinyl silicone oil A is prepared by mixing two vinyl silicone oils with a vinyl content of 0.3-10wt% and a vinyl content of 0.5-1.0wt%. The mixing ratio of the two vinyl silicone oils with a vinyl content of 0.3-10wt% and a vinyl content of 0.5-1.0wt% is 0.2-5.

5. The viscosity of the vinyl silicone oil with a vinyl content of 0.3-10wt% is 100 mPa·s-16000 mPa·s.

4. The two-component thermally conductive gel according to claim 1, characterized in that: The viscosity of hydrogen silicone oil is 50-500mPa.s; The calculation formula for the amount of hydrogen silicone oil is: M H =﹙M Vi ×A×Vi%﹚ / ﹙H%×27﹚ Where: M H is the mass of hydrogen silicone oil; M Vi is the mass of vinyl silicone oil; A is the molar ratio of active hydrogen in hydrogen-containing silicone oil to vinyl in all vinyl silicone oils in components A and B; Vi% is the mass fraction of vinyl in all vinyl silicone oils in components A and B; H% is the mass fraction of hydrogen in hydrogen-containing silicone oil; 27 is the molar mass of vinyl, and the mass fraction of active hydrogen in hydrogen-containing silicone oil is 0.05-0.2%.

5. A two-component thermally conductive gel according to claim 1, characterized in that: The viscosity of the vinyl silicone oil B is 5000 mPa·s-16000 mPa·s.

6. A two-component thermally conductive gel according to claim 1, characterized in that: The promoter is selected from Group VIII transition metals and their compounds or complexes.

7. A two-component thermally conductive gel according to claim 1 or 6, characterized in that: The promoter is a poisoning-resistant platinum catalyst.

8. A two-component thermally conductive gel according to claim 1, characterized in that: The thermal conductive powder is a spherical metal powder surface-treated with a silane coupling agent. The metal powder is one or a mixture of metal hydroxides, metal oxides, and metal nitrides. The median diameter D50 of the thermal conductive powder is 10-50 μm.

9. A two-component thermally conductive gel according to claim 1, characterized in that: The chain extender is an acetylene compound, a dibasic acid ester containing a double bond, or a nitrogen-containing compound.

10. The method for preparing the two-component thermally conductive gel according to any one of claims 1 to 9, characterized in that: The following steps are involved: By weight, 13-39 parts of compound vinyl silicone oil A and 0.018-0.06 parts of accelerator are added to a stirring device and stirred for 20-25 minutes. Then, 67-420 parts of thermal conductive powder are added to the stirring device in multiple times, each time with an interval of 10-15 minutes and stirred until there is no dry powder, no agglomeration, no obvious graininess or streaks. After the thermal conductive powder is added in batches, continue stirring and vacuum for 30-35 minutes to obtain component A; By weight, 0-20 parts of vinyl silicone oil B, 1-32 parts of hydrogenated silicone oil, and 0.036-0.12 parts of chain extender are added to a stirring device and stirred for 20-25 minutes. Then, 67-420 parts of thermal conductive powder are added to the stirring device in multiple times, each time with an interval of 10-15 minutes, and stirred until there is no dry powder, no agglomeration, no obvious graininess or streaks. After the thermal conductive powder is added in batches, continue stirring and vacuum for 30-35 minutes to obtain component B; Component A and component B are mixed evenly in proportion to obtain a two-component gel.

Images