Highly heat-conductive and strongly adhesive silicone rubber, preparation method and application thereof
By optimizing the formulation and process of silicone rubber components, a silicone rubber with high thermal conductivity and strong adhesion was prepared, which solved the problem that thermally conductive silicone rubber could not simultaneously possess both high thermal conductivity and strong adhesion, thus improving the heat dissipation performance and stability of electronic devices.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- INST OF CHEM CHINESE ACAD OF SCI
- Filing Date
- 2026-02-28
- Publication Date
- 2026-06-02
AI Technical Summary
Existing thermally conductive silicone rubbers cannot simultaneously possess both high thermal conductivity (thermal conductivity > 5 W/m·K) and strong adhesion (shear bond strength > 2 MPa), resulting in insufficient heat dissipation performance of electronic devices and affecting device stability.
By optimizing the formulation of silicone rubber components, including the proportions and processes of base rubber, thermally conductive filler, catalyst, crosslinking agent, polymerization inhibitor and reinforcing filler, high thermal conductivity and strong adhesion silicone rubber is prepared. This ensures that the thermally conductive filler is uniformly dispersed. Raw materials such as cyclosiloxane, cyclic oligomeric siloxane functional monomer, end-capping agent and alkali rubber are used, combined with appropriate mixing and vulcanization treatment.
It achieves a good balance between high thermal conductivity (>6W/m·K) and strong adhesion (>2MPa), improving the heat dissipation performance and operational stability of electronic devices.
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Abstract
Description
Technical Field
[0001] This invention belongs to the field of silicone rubber, specifically relating to a silicone rubber with high thermal conductivity and strong adhesion, its preparation method, and its application. Background Technology
[0002] As electronic devices are constantly being updated and iterated, core components are trending towards miniaturization, while operating power is increasing daily. This means that if heat dissipation is not improved, components will overheat, potentially leading to equipment failure. Statistics show that for every 25°C increase in the core temperature of a device, the probability of failure increases tenfold; and the biggest factor limiting the heat dissipation performance of a device is often the interface thermal resistance.
[0003] Silicone rubber plays a crucial role in thermally conductive bonding applications in electronic packaging and thermal interface materials due to its excellent weather resistance, electrical insulation, and flexibility. Silicone rubber is a soft material made from polysiloxane as a matrix, usually compounded with inorganic fillers to form a raw rubber. It is produced through addition or condensation reactions via end groups and other modification groups, followed by vulcanization under specific temperature and humidity conditions. Adding thermally conductive fillers to silicone rubber yields thermally conductive silicone rubber, which possesses high thermal conductivity. Due to the stability of the siloxane structure, thermally conductive silicone rubber exhibits advantages such as corrosion resistance and resistance to yellowing. Therefore, using thermally conductive silicone rubber can effectively reduce interfacial thermal resistance while enhancing the operational stability of electronic devices under extreme conditions. However, currently used thermally conductive silicone rubbers suffer from limited thermally conductive bonding performance; it is difficult to simultaneously possess high thermal conductivity (thermal conductivity > 5 W / m·K) and strong bonding performance (shear bond strength > 2 MPa). Therefore, developing a thermally conductive silicone rubber with strong bonding properties is of great significance to the development of electronic devices. Summary of the Invention
[0004] To solve the above-mentioned technical problems, the technical solution provided by the present invention is as follows: A high thermal conductivity and strong adhesive silicone rubber, comprising the following components in parts by weight: 100 parts base adhesive, 500-2500 parts thermally conductive filler, 0-50 parts reinforcing filler, 0.5-1 part catalyst, 0.05-0.5 parts polymerization inhibitor, and 5-10 parts crosslinking agent; The raw materials of the base adhesive include: cyclosiloxane, cycloolithomic oligosiloxane functional monomer, end-capping agent and alkali adhesive.
[0005] Preferably, in the raw materials of the base adhesive, per 100 parts by weight of cyclic oligomeric siloxane functional monomers, 10-30 parts by weight of end-capping agent, and 2-4 parts by weight of alkaline adhesive.
[0006] According to an embodiment of the present invention, in the high thermal conductivity and strong adhesion silicone rubber, the mass ratio of the base rubber to the thermally conductive filler is 100:500-2500, for example, 100:1000, 100:1500, 100:2000 or any two of the above values.
[0007] According to an embodiment of the present invention, the cyclosiloxane is selected from at least one of hexamethylcyclotrisiloxane (D3), octamethylcyclotetrasiloxane (D4), and decamethylcyclopentasiloxane (D5).
[0008] According to an embodiment of the present invention, the cyclic oligomeric siloxane functional monomer is selected from at least one of glycidyl etheroxypropylcyclotrisiloxane (PGE-D3), glycidyl etheroxypropylcyclotetrasiloxane (PGE-D4), and glycidyl etheroxypropylcyclopentasiloxane (PGE-D5).
[0009] For example, in the raw materials of the base adhesive, the cyclosiloxane is selected from octamethylcyclotetrasiloxane (D4), and the cyclic oligomeric siloxane functional monomer is selected from glycidyl etheroxypropylcyclotetrasiloxane (PGE-D4).
[0010] According to an embodiment of the present invention, the capping agent is selected from vinyl-containing capping agents, such as divinyltetramethyldisiloxane (MM). vi ), divinyltetramethyldisilazane (MM) viN At least one of the following: dimethylvinylsilane, etc.
[0011] According to an embodiment of the present invention, the alkaline gel is selected from tetramethylammonium hydroxide (TMAH) or a strong alkaline catalyst. Preferably, the strong alkaline catalyst is selected from potassium hydroxide and / or sodium hydroxide.
[0012] According to an embodiment of the present invention, the thermally conductive filler is selected from at least one of alumina, aluminum nitride, diamond, etc. Preferably, the thermally conductive filler is a powder. Preferably, the present invention does not specifically limit the particle size of the thermally conductive filler, and can select a particle size range known in the art, or a single particle size or multiple particle sizes. Exemplarily, the particle size of the thermally conductive filler is selected from 1-100 μm, for example, 10 μm, 100 μm, or a mixture of two particle sizes (for example, the mixing ratio of thermally conductive fillers with 10 μm and 100 μm particle sizes is 1:1).
[0013] According to an embodiment of the present invention, in the high thermal conductivity and strong adhesion silicone rubber, the mass fraction of the thermally conductive filler is 1000-2500 parts, for example, 1000 parts, 1500 parts, 2000 parts or any two of the above values.
[0014] According to an embodiment of the present invention, the crosslinking agent is selected from hydrogen-containing silicone oil (polymethylhydrosiloxane, PHMS).
[0015] According to an embodiment of the present invention, in the high thermal conductivity and strong adhesion silicone rubber, the mass fraction of the crosslinking agent is 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, 10 parts, or any two of the above values.
[0016] According to an embodiment of the present invention, the catalyst is selected from platinum catalysts, preferably cassette catalysts.
[0017] According to an embodiment of the present invention, in the high thermal conductivity and strong adhesion silicone rubber, the mass fraction of the catalyst is 0.5 parts, 0.6 parts, 0.7 parts, 0.8 parts, 0.9 parts, 1 part, or any two of the above values.
[0018] According to an embodiment of the present invention, the polymerization inhibitor is selected from at least one of alkynyl alcohol polymerization inhibitors and vinyl-containing siloxane polymerization inhibitors. Preferably, the vinyl-containing siloxane polymerization inhibitor is selected from divinyltetramethyldisiloxane (MM). vi The polymerization inhibitor is selected from at least one of tetramethyltetravinylsiloxane, vinyl silicone oil, etc. Preferably, the alkynyl alcohol polymerization inhibitor is selected from at least one of etynylcyclohexanol (ECH), methylbutynol (MBY), dimethylhexynol (DMHD), etc.
[0019] According to an embodiment of the present invention, in the high thermal conductivity and strong adhesion silicone rubber, the mass fraction of the polymerization inhibitor is 0.05 parts, 0.1 parts, 0.2 parts, 0.3 parts, 0.4 parts, 0.5 parts, or any two of the above values.
[0020] According to an embodiment of the present invention, the reinforcing filler is selected from at least one of fumed silica, precipitated silica, calcium carbonate, and other reinforcing fillers. Preferably, the reinforcing filler is a powder.
[0021] According to an embodiment of the present invention, in the high thermal conductivity and strong adhesion silicone rubber, the mass fraction of the reinforcing filler is 5 parts, 10 parts, 15 parts, 20 parts, 30 parts, 40 parts, or any two of the above values.
[0022] The present invention also provides a method for preparing the above-mentioned high thermal conductivity and strong adhesion silicone rubber, the preparation method comprising the following steps: (1) Mix the raw materials of the base glue, synthesize the crude product, purify it, and obtain the base glue; (2) The base rubber obtained in step (1) is mixed with crosslinking agent, catalyst, polymerization inhibitor and thermally conductive filler, and optionally vulcanized or not vulcanized to obtain the high thermal conductivity and strong adhesion silicone rubber.
[0023] According to an embodiment of the present invention, in step (1), the raw materials of the base adhesive have the meanings described above. Preferably, the alkali adhesive is used as a synthesis catalyst during synthesis.
[0024] According to an embodiment of the present invention, in step (1), the conditions for the synthesis of the base adhesive include: a reaction temperature of 50-100°C, for example 85°C; and a reaction time of 1-5 h, for example 3 h.
[0025] According to an embodiment of the present invention, in step (1), purification specifically includes: heating the crude product to decompose the alkaline gum, and then removing impurities. Preferably, the heating temperature of the crude product is 100-200℃, for example, 150℃; and the heating time is 10-60min, for example, 30min.
[0026] Preferably, the method for removing impurities specifically involves: after the alkaline gum has decomposed, washing with an alcohol solvent (such as methanol and / or ethanol) and / or vacuum distillation. Further, when washing with an alcohol solvent, vacuum distillation can be performed to remove the alcohol solvent, for example, vacuum distillation at 120°C for 2 hours.
[0027] According to an embodiment of the present invention, in step (2), the mixing can be carried out using methods known in the art, such as mixing in a mixing tank using a mixer at room temperature. Furthermore, zirconium balls can also be added to the mixing tank; the amount of zirconium balls added can be any method known in the art, and the present invention does not impose a specific limitation.
[0028] According to the embodiment of the present invention, in step (2), in order to avoid cross-linking vulcanization caused by high temperature of the system during mixing, the preparation method of first mixing other components and then adding cross-linking agent and mixing for a few seconds can be adopted.
[0029] According to an embodiment of the present invention, in step (2), the conditions for the vulcanization treatment are selected from at least one of the following (a)-(c): (a) Heat at 100-150°C (e.g., 120°C) for 1-2 hours; (b) Heat at 150℃-200℃ (e.g., 170℃) and 5-10MPa (e.g., 7MPa) for 5-30 min (e.g., 20 min); (c) Place at room temperature for 10-30 hours (e.g., 24 hours).
[0030] The present invention also provides the application of the above-mentioned high thermal conductivity and strong adhesion silicone rubber in electronic devices.
[0031] Beneficial effects This invention provides a high thermal conductivity and strong adhesion silicone rubber, which can be uniformly dispersed at ultra-high filler content to obtain a thermally conductive and adhesive silicone rubber, and has high thermal conductivity (>6W / m·K) and strong adhesion (>2MPa) properties, achieving a good balance between high thermal conductivity and strong adhesion.
[0032] The high thermal conductivity and strong adhesion silicone rubber provided by this invention can be widely used as a high-performance thermally conductive adhesive in various electronic devices. It breaks through the technical bottleneck that it is difficult to synergistically improve the high thermal conductivity and strong adhesion performance of silicone rubber materials, and provides a new material solution for improving the heat dissipation performance of electronic devices. Detailed Implementation
[0033] The technical solution of the present invention will be further described in detail below with reference to specific embodiments. It should be understood that the following embodiments are merely illustrative and explanatory of the present invention, and should not be construed as limiting the scope of protection of the present invention. All technologies implemented based on the above content of the present invention are covered within the scope of protection intended by the present invention.
[0034] Unless otherwise stated, the raw materials and reagents used in the following examples are commercially available products or can be prepared by known methods.
[0035] Example 1 Add parts by weight of D4100, 2.37 parts by weight of PGE-D412, and end-capping agent MM to a three-necked flask. vi 1.41 parts by weight, using 3 parts by weight of TMAH alkaline gum as a catalyst, were immersed in methyl silicone oil in a three-necked flask at 85°C for 3 hours to obtain crude silicone oil product; then the crude product was washed three times with methanol and dried under vacuum at 100°C for 4 hours to obtain base gum A.
[0036] Example 2 Add parts by weight of D4100, 2.37 parts by weight of PGE-D412, and end-capping agent MM to a three-necked flask. vi 4.35 parts by weight, using 3 parts by weight of TMAH alkaline gum as a catalyst, were immersed in methyl silicone oil in a three-necked flask at 85°C for 3 hours to obtain crude silicone oil product; then the crude product was washed three times with methanol and dried under vacuum at 100°C for 4 hours to obtain base gum B.
[0037] Example 3 Add parts by weight of D4100, 11 parts by weight of PGE-D426, and end-capping agent MM to a three-necked flask. vi 1.59 parts by weight, using 3 parts by weight of TMAH alkaline gum as a catalyst, were immersed in methyl silicone oil in a three-necked flask at 85°C for 3 hours to obtain crude silicone oil product; then the crude product was washed three times with methanol and dried under vacuum at 100°C for 4 hours to obtain base gum C.
[0038] Example 4 Add parts by weight of D4100, 11 parts by weight of PGE-D426, and end-capping agent MM to a three-necked flask. vi 4.88 parts by weight, using 3 parts by weight of TMAH alkaline gum as a catalyst, were immersed in methyl silicone oil in a three-necked flask at 85°C for 3 hours to obtain crude silicone oil product; then the crude product was washed three times with methanol and dried under vacuum at 100°C for 4 hours to obtain base gum D.
[0039] Example 5 Add 100 parts by weight of base adhesive A, 7.14 parts by weight of PHMS, 0.5 parts by weight of caster platinum (Pt) catalyst, and polymerization inhibitor MM to a mixing tank. vi 0.5 parts by weight, 2000 parts by weight of Al2O3 thermally conductive filler and a certain amount of zirconium beads are mixed in a mixer at 2000 rpm for 30 seconds at room temperature to obtain a high thermal conductivity and strong adhesion silicone rubber. In this embodiment, two types of Al2O3 thermally conductive filler with particle sizes of 100μm and 10μm are selected, and the ratio is 1:1. Unless otherwise specified in the following embodiments, the particle size of Al2O3 thermally conductive filler is the same as in this embodiment.
[0040] Example 6 Add 100 parts by weight of base adhesive A, 7.14 parts by weight of PHMS, 0.5 parts by weight of caster platinum (Pt) catalyst, and polymerization inhibitor MM to a mixing tank. vi 0.5 parts by weight of Al2O3 thermally conductive filler, 2000 parts by weight of fumed silica, and a certain amount of zirconium beads were mixed in a mixer at 2000 rpm for 30 seconds at room temperature to obtain a high thermal conductivity and strong adhesion silicone rubber.
[0041] Example 7 Add 100 parts by weight of base adhesive A, 7.14 parts by weight of PHMS, 0.5 parts by weight of caster platinum (Pt) catalyst, and polymerization inhibitor MM to a mixing tank. vi 0.5 parts by weight of Al2O3 thermally conductive filler, 2000 parts by weight of fumed silica, and a certain amount of zirconium beads were mixed in a mixer at 2000 rpm for 30 seconds at room temperature to obtain a high thermal conductivity and strong adhesion silicone rubber.
[0042] Example 8 Add 100 parts by weight of base adhesive A, 7.14 parts by weight of PHMS, 0.5 parts by weight of caster platinum (Pt) catalyst, and polymerization inhibitor MM to a mixing tank. vi0.5 parts by weight of Al2O3 thermally conductive filler, 2000 parts by weight of fumed silica, and a certain amount of zirconium beads were mixed in a mixer at 2000 rpm for 30 seconds at room temperature to obtain a high thermal conductivity and strong adhesion silicone rubber.
[0043] Example 9 Add 100 parts by weight of base adhesive A, 7.14 parts by weight of PHMS, 0.5 parts by weight of caster platinum (Pt) catalyst, and polymerization inhibitor MM to a mixing tank. vi 0.5 parts by weight of Al2O3 thermally conductive filler, 2000 parts by weight of fumed silica, and a certain amount of zirconium beads were mixed in a mixer at 2000 rpm for 30 seconds at room temperature to obtain a high thermal conductivity and strong adhesion silicone rubber.
[0044] Example 10 Add 100 parts by weight of base adhesive A, 7.14 parts by weight of PHMS, 0.5 parts by weight of caster platinum (Pt) catalyst, and polymerization inhibitor MM to a mixing tank. vi 0.5 parts by weight of Al2O3 thermally conductive filler, 2000 parts by weight of fumed silica, and a certain amount of zirconium beads were mixed in a mixer at 2000 rpm for 30 seconds at room temperature to obtain a high thermal conductivity and strong adhesion silicone rubber.
[0045] Example 11 Add 100 parts by weight of base rubber A, 1 part by weight of caster platinum (Pt) catalyst, 0.07 parts by weight of polymerization inhibitor 2-methyl-3-butyn-2-ol, 2000 parts by weight of thermally conductive Al2O3 filler, 50 parts by weight of fumed silica, and a number of zirconium beads to a mixing tank. Mix at 2000 rpm for 20 s at room temperature using a mixer. Then add 7.14 parts by weight of PHMS and mix at 2000 rpm for 10 s to obtain a high thermal conductivity and strong adhesion silicone rubber.
[0046] Example 12 Add 100 parts by weight of base rubber A, 1 part by weight of caster platinum (Pt) catalyst, 0.15 parts by weight of polymerization inhibitor 2-methyl-3-butyn-2-ol, 2000 parts by weight of thermally conductive Al2O3 filler, 50 parts by weight of fumed silica, and a number of zirconium beads to a mixing tank. Mix at 2000 rpm for 20 s at room temperature using a mixer. Then add 7.14 parts by weight of PHMS and mix at 2000 rpm for 10 s to obtain a high thermal conductivity and strong adhesion silicone rubber.
[0047] Example 13 Add 100 parts by weight of base rubber B, 1 part by weight of caster platinum (Pt) catalyst, 0.07 parts by weight of polymerization inhibitor 2-methyl-3-butyn-2-ol, 2000 parts by weight of thermally conductive Al2O3 filler, 50 parts by weight of fumed silica, and a number of zirconium beads to a mixing tank. Mix at 2000 rpm for 20 s at room temperature using a mixer. Then add 7.14 parts by weight of PHMS and mix at 2000 rpm for 10 s to obtain a high thermal conductivity and strong adhesion silicone rubber.
[0048] Example 14 Add 100 parts by weight of base rubber C, 1 part by weight of caster platinum (Pt) catalyst, 0.07 parts by weight of polymerization inhibitor 2-methyl-3-butyn-2-ol, 2000 parts by weight of thermally conductive Al2O3 filler, 50 parts by weight of fumed silica, and a number of zirconium beads to a mixing tank. Mix at 2000 rpm for 20 s at room temperature using a mixer. Then add 7.14 parts by weight of PHMS and mix at 2000 rpm for 10 s to obtain a high thermal conductivity and strong adhesion silicone rubber.
[0049] Example 15 Add 100 parts by weight of base rubber D, 1 part by weight of caster platinum (Pt) catalyst, 0.07 parts by weight of polymerization inhibitor 2-methyl-3-butyn-2-ol, 2000 parts by weight of thermally conductive Al2O3 filler, 50 parts by weight of fumed silica, and a number of zirconium beads to a mixing tank. Mix at 2000 rpm for 20 s at room temperature using a mixer. Then add 7.14 parts by weight of PHMS and mix at 2000 rpm for 10 s to obtain a high thermal conductivity and strong adhesion silicone rubber.
[0050] Comparative Example 1 Referring to the formulation and process of Example 11, the difference lies in the following: Vinyl dimethyl silicone oil with a viscosity of 200 cP was used as the base adhesive instead of base adhesive A. In a mixing tank, 100 parts by weight of this base adhesive, 1 part by weight of casterplatin (Pt) catalyst, 0.07 parts by weight of polymerization inhibitor 2-methyl-3-butyn-2-ol, 2000 parts by weight of Al2O3 thermally conductive filler, 50 parts by weight of fumed silica, and a certain amount of zirconium beads were added. The mixture was stirred at 2000 rpm for 20 seconds at room temperature using a mixer. Then, 7.14 parts by weight of PHMS were added, and the mixture was stirred at 2000 rpm for 10 seconds. Due to the poor compatibility of this mixture, a uniform paste could not be formed, leading to mixing failure and thus, no testable sample could be prepared.
[0051] Comparative Example 2 Add 100 parts by weight of base adhesive A, 7.14 parts by weight of PHMS, 0.5 parts by weight of caster platinum (Pt) catalyst, and polymerization inhibitor MM to a mixing tank. vi0.5 parts by weight were mixed at room temperature using a mixer at 2000 rpm for 30 seconds to obtain a high thermal conductivity and strong adhesive silicone rubber.
[0052] Comparative Example 3 Add 100 parts by weight of base adhesive A, 7.14 parts by weight of PHMS, 0.5 parts by weight of caster platinum (Pt) catalyst, and polymerization inhibitor MM to a mixing tank. vi 0.5 parts by weight of Al2O3 thermally conductive filler, 500 parts by weight of Al2O3 and a certain amount of zirconium beads were mixed in a mixer at 2000 rpm for 30 seconds at room temperature to obtain a high thermal conductivity and strong adhesion silicone rubber.
[0053] Comparative Example 4 Add 100 parts by weight of base adhesive A, 7.14 parts by weight of PHMS, 0.5 parts by weight of caster platinum (Pt) catalyst, and polymerization inhibitor MM to a mixing tank. vi 0.5 parts by weight, 1000 parts by weight of Al2O3 thermally conductive filler, and a certain amount of zirconium beads were mixed in a mixer at 2000 rpm for 30 seconds at room temperature to obtain a high thermal conductivity and strong adhesion silicone rubber.
[0054] Comparative Example 5 Add 100 parts by weight of base adhesive A, 7.14 parts by weight of PHMS, 0.5 parts by weight of caster platinum (Pt) catalyst, and polymerization inhibitor MM to a mixing tank. vi 0.5 parts by weight of Al2O3 thermally conductive filler, 1500 parts by weight of Al2O3 and a certain amount of zirconium beads were mixed in a mixer at 2000 rpm for 30 seconds at room temperature to obtain a high thermal conductivity and strong adhesion silicone rubber.
[0055] Comparative Example 6 Add 100 parts by weight of base adhesive A, 7.14 parts by weight of PHMS, 0.5 parts by weight of caster platinum (Pt) catalyst, and polymerization inhibitor MM to a mixing tank. vi 0.5 parts by weight, 2500 parts by weight of Al2O3 thermally conductive filler, and a certain amount of zirconium beads were mixed in a mixer at 2000 rpm for 30 seconds at room temperature to obtain a high thermal conductivity and strong adhesion silicone rubber.
[0056] Test case The high thermal conductivity and strong adhesion silicone rubbers prepared in the above examples and comparative examples were subjected to the following performance tests: (1) Shear bond strength: The thermally conductive adhesive silicone rubber prepared in the above examples and comparative examples were used as adhesives to prepare standard overlapping test pieces (two rigid materials are aluminum sheets) according to GB / T 7124-2008. They were baked at 120℃ for 120 minutes and cooled to room temperature. The shear bond strength was tested according to GB / T 7124-2008 standard. The test results are listed in Table 1.
[0057] The above tests were repeated, with the thermally conductive adhesive silicone rubber of Examples 11, 13, 14 and 15 used as adhesives, and the rigid materials were replaced with steel sheets and epoxy resin-glass fiber composite materials, respectively. The test results are listed in Table 2.
[0058] (2) Thermal conductivity: The thermally conductive adhesive silicone rubber prepared in the above examples and comparative examples was poured into an iron (coated with polytetrafluoroethylene) mold, and hot-pressed at 170°C and 7MPa for 20 minutes. After cooling to room temperature, the thermal conductivity was tested using ASTM D7984 standard. The test results are listed in Table 1.
[0059] Table 1. Test results of thermal conductivity and shear bond strength of lap joint specimens of aluminum sheet substrates.
[0060] The results in Table 1 show that: The experimental results of Comparative Example 1 show that using conventional vinyl dimethyl silicone oil as the base adhesive, it is impossible to achieve good processing and mixing of 2000 parts by mass of thermally conductive filler, which proves that there are technical difficulties in the high-filler system. The experimental results of Comparative Examples 2-5 show that when the mass fraction of Al2O3 thermally conductive filler is less than 2000, it is impossible to guarantee a thermal conductivity of 6 W / m·K. The experimental results of Comparative Example 6 show that if the mass fraction of Al2O3 thermally conductive filler is higher than 2000, the bonding strength will decrease.
[0061] Table 2. Shear bond strength test results of lapped specimens of different materials
[0062] The results in Table 2 show that the thermally conductive adhesive silicone rubber of the present invention not only has a good bonding effect on aluminum sheets, but also has a similar bonding effect on steel sheets, and also has a certain bonding ability on epoxy resin-glass fiber composite materials.
[0063] The test results above show that the epoxy-modified silicone rubber (such as base rubber AD) prepared by this invention can be uniformly dispersed at ultra-high filler content to obtain thermally conductive adhesive silicone rubber, which has high thermal conductivity (>6W / m·K) and strong adhesion (>2MPa). Specifically, the thermally conductive adhesive silicone rubber prepared in Example 15 of this invention, while maintaining a thermal conductivity of not less than 6W / m·K, exhibits an adhesion strength of up to 2.80MPa to aluminum sheets and an adhesion strength exceeding 3MPa to steel sheets.
[0064] The exemplary embodiments of the present invention have been described above. However, the scope of protection of the present invention is not limited to the above embodiments. Any modifications, equivalent substitutions, improvements, etc., made by those skilled in the art within the spirit and principles of the present invention should be included within the scope of protection of the present invention.
Claims
1. A silicone rubber with high thermal conductivity and strong adhesion, characterized in that, It comprises the following components in parts by mass: 100 parts base adhesive, 500-2500 parts thermally conductive filler, 0-50 parts reinforcing filler, 0.5-1 part catalyst, 0.05-0.5 parts polymerization inhibitor, and 5-10 parts crosslinking agent; The raw materials of the base adhesive include: cyclosiloxane, cycloolithomic oligosiloxane functional monomer, end-capping agent and alkali adhesive.
2. The high thermal conductivity and strong adhesion silicone rubber according to claim 1, characterized in that, In the raw materials of the base adhesive, per 100 parts by weight of cyclic oligomeric siloxane functional monomers, 10-30 parts by weight of end-capping agent, and 2-4 parts by weight of alkaline adhesive. The mass ratio of base adhesive to thermally conductive filler is 100:500-2500.
3. The high thermal conductivity and strong adhesion silicone rubber according to claim 1, characterized in that, The cyclosiloxane is selected from at least one of hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, and decamethylcyclopentasiloxane; The cyclic oligomeric siloxane functional monomer is selected from at least one of glycidyl etheroxypropylcyclotrisiloxane, glycidyl etheroxypropylcyclotetrasiloxane, and glycidyl etheroxypropylcyclopentasiloxane. The end-capping agent is selected from end-capping agents containing vinyl groups; the end-capping agent containing vinyl groups is at least one of divinyltetramethyldisiloxane, divinyltetramethyldisilazane, and dimethylvinylsilane. The alkaline gel is selected from tetramethylammonium hydroxide or a strong alkaline catalyst; the strong alkaline catalyst is selected from potassium hydroxide and / or sodium hydroxide.
4. The high thermal conductivity and strong adhesion silicone rubber according to claim 1, characterized in that, The thermally conductive filler is selected from at least one of alumina, aluminum nitride, and diamond. In the high thermal conductivity and strong adhesion silicone rubber, the thermally conductive filler has a mass fraction of 1000-2500 parts.
5. The high thermal conductivity and strong adhesion silicone rubber according to claim 1, characterized in that, The crosslinking agent is selected from hydrogen-containing silicone oil; The catalyst is selected from platinum catalysts; The polymerization inhibitor is selected from at least one of alkynyl alcohol polymerization inhibitors and vinyl-containing siloxane polymerization inhibitors; the vinyl-containing siloxane polymerization inhibitor is selected from at least one of divinyltetramethyldisiloxane, tetramethyltetravinylsiloxane, and vinyl silicone oil; the alkynyl alcohol polymerization inhibitor is selected from at least one of ethynylcyclohexanol, methylbutynol, and dimethylhexynol. The reinforcing filler is selected from at least one of fumed silica, precipitated silica, and calcium carbonate.
6. The method for preparing the high thermal conductivity and strong adhesion silicone rubber according to any one of claims 1-5, characterized in that, The preparation method includes the following steps: (1) Mix the raw materials of the base glue, synthesize the crude product, purify it, and obtain the base glue; (2) The base rubber obtained in step (1) is mixed with crosslinking agent, catalyst, polymerization inhibitor and thermally conductive filler, and optionally vulcanized to obtain the high thermal conductivity and strong adhesion silicone rubber.
7. The preparation method according to claim 6, characterized in that, The alkaline gum serves as a synthesis catalyst during the synthesis process; In step (1), the conditions for synthesizing the base adhesive include: a reaction temperature of 50-100℃ and a reaction time of 1-5h.
8. The preparation method according to claim 6, characterized in that, In step (1), purification specifically includes: heating the crude product to decompose the alkaline gum, and then removing impurities; the heating temperature of the crude product is 100-200℃; the heating time is 10-60min; The specific method for removing impurities is as follows: after the alkaline gum is decomposed, it is washed with an alcohol solvent and / or distilled under reduced pressure; when washing with an alcohol solvent, further distillation under reduced pressure is performed to remove the alcohol solvent. In step (2), to avoid cross-linking and vulcanization caused by high temperature during mixing, other components can be mixed first, and then the cross-linking agent can be added and mixed for a few seconds.
9. The preparation method according to claim 6, characterized in that, In step (2), the conditions for the vulcanization treatment are selected from at least one of the following (a)-(c): (a) Heat at 100-150℃ for 1-2 hours; (b) Heat at 150℃-200℃ and 5-10MPa for 5-30 minutes; (c) Place at room temperature for 10-30 hours.
10. The application of the high thermal conductivity and strong adhesion silicone rubber according to any one of claims 1-5 in electronic devices.