Thermally conductive silicone adhesive composition
By combining specific components, a thermal grease was prepared, which solved the problem that existing thermal greases could not simultaneously meet the requirements of low thermal resistance, low viscosity, high breakdown voltage and anti-pumping performance, and achieved excellent thermal conductivity and adhesion properties.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- HENKEL KGAA
- Filing Date
- 2023-10-13
- Publication Date
- 2026-05-08
AI Technical Summary
Existing thermal greases cannot simultaneously meet the requirements of low thermal resistance, low viscosity suitable for printing processes, high breakdown voltage, and good anti-pumping performance.
A thermally conductive silicone adhesive composition is formed by using an alkenyl-containing organopolysiloxane, an alkyl-terminated organopolysiloxane, a silane coupling agent, and a mixture of alumina, silicon carbide, and zinc oxide with specific particle sizes as components.
It achieves a thermal resistance of less than 0.06 K·cm2/W, a viscosity of 100 to 300 Pa·s, a breakdown voltage of more than 3 kV/mm, and good anti-pumping performance for 200 cycles at -40 to 125°C.
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Abstract
Description
Technical Field
[0001] This invention relates to thermally conductive silicone adhesive compositions, and more particularly to such thermally conductive silicone adhesive compositions exhibiting low thermal impedance, low viscosity suitable for printing processes, high breakdown voltage, and good anti-pumping properties. Background Technology
[0002] In recent years, with the reduction in size and improvement in performance of electronic devices, the requirements for thermal greases in terms of thermal conductivity, viscosity, electrical insulation, and anti-pumping properties have been increasing. In particular, none of the existing thermal greases on the market can simultaneously meet the following requirement: thermal resistance below 0.06 K·cm. 2 It has a viscosity of 100 to 300 Pa·s at 25°C, a breakdown voltage of over 3 kV / mm, and good anti-pumping properties for 200 cycles at -40 to 125°C.
[0003] In view of the above, it is desirable to provide a thermally conductive silicone composition that exhibits low thermal resistance, low viscosity suitable for printing processes, high breakdown voltage, and good anti-pumping properties. Summary of the Invention
[0004] The present invention provides a thermally conductive silicone adhesive composition, the thermally conductive silicone adhesive composition comprising: (A) Alkenyl-containing organopolysiloxanes; (B) Alkyl-terminated organopolysiloxanes; (C) Silane coupling agent; (D) Catalyst; and (E)(e-1)D 50 Alumina with a particle size of 4 to 8 μm, (e-2)D 50 Silicon carbide with a particle size of 1 to 4 μm and (e-3)D 50 A mixture of alumina and / or zinc oxide with a particle size of less than 1 μm.
[0005] The present invention also provides cured products of thermally conductive silicone adhesive compositions according to the present invention.
[0006] The present invention further provides the use of the thermally conductive silicone adhesive composition according to the invention or the cured product according to the invention in the manufacture of electronic devices.
[0007] The thermally conductive silicone adhesive composition, cured product, and uses according to the invention are all based on the inventors' surprising discovery that the thermally conductive silicone adhesive composition according to the invention—which utilizes a specific combination of components (A) to (E), especially a specific combination of components (e-1), (e-2), and (e-3)—exhibits low thermal resistance, low viscosity suitable for printing processes, high breakdown voltage, and good anti-pumping properties; and in particular, it simultaneously exhibits a thermal conductivity below 0.06 K·cm⁻¹. 2 Thermal resistance of / W, viscosity at 25°C of 100 to 300 Pa·s, breakdown voltage above 3 kV / mm, and good anti-pumping performance for 200 cycles at -40 to 125°C. Detailed Implementation
[0008] Those skilled in the art will understand that this discussion is merely a description of exemplary embodiments and is not intended to limit the broader aspects of the invention. Unless expressly stated to the contrary, each aspect thus described may be combined with any one or more other aspects. In particular, any feature indicated as preferred or advantageous may be combined with any one or more other features indicated as preferred or advantageous.
[0009] Unless otherwise stated, as used herein, the terms “a,” “an,” “the,” and “the” include both singular and plural references to the object.
[0010] The term “comprising” as used herein is synonymous with “including,” “containing,” or “containing,” and is inclusive or open-ended, and does not exclude additional, unlisted members, elements, or method steps.
[0011] Unless otherwise stated, the enumeration of numerical endpoints includes all numerical values, fractions, and the listed endpoints that fall within the corresponding range.
[0012] Unless otherwise stated, all terms “room temperature” as used herein refer to 23±2℃.
[0013] Unless otherwise stated, all molecular weights used herein refer to weight-average molecular weight (Mw), which is obtained by gel permeation chromatography (GPC) according to DIN 55672.
[0014] Unless otherwise stated, all instances of "D" in this document are considered valid. 50 "Particle size" refers to the median diameter in the volume-based particle size distribution curve obtained by measuring with a laser diffraction particle size analyzer.
[0015] Unless otherwise stated, all parameters used herein were measured according to the methods described in the working embodiments of this specification, if any.
[0016] Unless otherwise defined, all terms (including technical and scientific terms) used in this invention shall have the meanings commonly understood by one of ordinary skill in the art to which this invention pertains.
[0017] According to the present invention, surprisingly, the inventors have discovered a thermally conductive silicone adhesive composition comprising: (A) Alkenyl-containing organopolysiloxanes; (B) Alkyl-terminated organopolysiloxanes; (C) Silane coupling agent; (D) Catalyst; and (E)(e-1)D 50 Alumina with a particle size of 4 to 8 μm, (e-2)D 50 Silicon carbide with a particle size of 1 to 4 μm and (e-3)D 50 A mixture of alumina and / or zinc oxide with a particle size of less than 1 μm. It exhibits low thermal resistance, low viscosity suitable for printing processes, high breakdown voltage, and good anti-pumping properties.
[0018] In a first aspect, this disclosure generally relates to thermally conductive silicone adhesive compositions comprising: (A) Alkenyl-containing organopolysiloxanes; (B) Alkyl-terminated organopolysiloxanes; (C) Silane coupling agent; (D) Catalyst; and (E)(e-1)D 50 Alumina with a particle size of 4 to 8 μm, (e-2)D 50 Silicon carbide with a particle size of 1 to 4 μm and (e-3)D 50 A mixture of alumina and / or zinc oxide with a particle size of less than 1 μm.
[0019] (A) Alkenyl-containing organopolysiloxanes According to the present invention, the thermally conductive silicone adhesive composition comprises (A) an alkenyl-containing organopolysiloxane.
[0020] As used herein, “alkenyl” refers to a straight-chain or branched hydrocarbon group having 2 to 40 carbon atoms and one or more carbon-carbon double bonds (e.g., 1, 2, 3, or 4 double bonds). 2-40 Alkenyl group (“Alkenyl”). In some embodiments, the alkenyl group has 2 to 30 carbon atoms (“C”). 2-30 Alkenyl group (“Alkenyl”). In some embodiments, the alkenyl group has 2 to 20 carbon atoms (“C2”). 2-20 Alkenyl group (“Alkenyl”). In some embodiments, the alkenyl group has 2 to 10 carbon atoms (“C”). 2-10Alkenyl group (“Alkenyl”). In some embodiments, the alkenyl group has 2 to 9 carbon atoms (“C”). 2-9 Alkenyl group (“Alkenyl”). In some embodiments, the alkenyl group has 2 to 8 carbon atoms (“C”). 2-8 Alkenyl group (“Alkenyl”). In some embodiments, the alkenyl group has 2 to 7 carbon atoms (“C”). 2-7 Alkenyl group (“Alkenyl”). In some embodiments, the alkenyl group has 2 to 6 carbon atoms (“C”). 2-6 Alkenyl group (“Alkenyl”). In some embodiments, the alkenyl group has 2 to 5 carbon atoms (“C”). 2-5 Alkenyl group (“Alkenyl”). In some embodiments, the alkenyl group has 2 to 4 carbon atoms (“C”). 2-4 Alkenyl group (“Alkenyl”). In some embodiments, the alkenyl group has 2 to 3 carbon atoms (“C”). 2-3 The alkenyl group (“C2-alkenyl”) has two carbon atoms in some embodiments. One or more carbon-carbon double bonds can be internal (e.g., in 2-butenyl) or terminal (e.g., in 1-butenyl). 2-4 Examples of alkenyl groups include vinyl (C2), 1-propenyl (C3), 2-propenyl (C3), 1-butenyl (C4), 2-butenyl (C4), butadienyl (C4), etc. 2-6 Examples of alkenyl groups include the aforementioned C... 2-4 Alkenyl groups include pentenyl (C5), pentadienyl (C5), hexenyl (C6), etc. Other examples of alkenyl groups include heptenyl (C7), octenyl (C8), octetrinyl (C8), etc. Unless otherwise stated, each example of an alkenyl group is independently unsubstituted (“unsubstituted alkenyl”) or substituted with one or more substituents (“substituted alkenyl”). In some embodiments, the alkenyl group is an unsubstituted C5 group. 2-30 Alkenyl group. In some embodiments, the alkenyl group is a substituted C. 2-30 Alkenyl group.
[0021] In some embodiments, the amount of alkenyl groups is in the range of 0.01 to 10% by weight, and preferably in the range of 0.1 to 5% by weight, based on the total weight of the alkenyl-containing organopolysiloxane.
[0022] In some embodiments, the viscosity of component (A) at 25°C is less than 1000 mPa·s, preferably less than 500 mPa·s, and more preferably less than 200 mPa·s. The viscosity described herein was measured using a TA rheometer with a parallel plate and a 25 mm rotor at 60 rpm and 25°C.
[0023] There are no particular restrictions on the molecular structure of component (A), including but not limited to linear structures, cyclic structures, branched structures, partially branched linear structures, and three-dimensional network structures. Furthermore, component (A) can be a single polymer having such a molecular structure, a copolymer having such a molecular structure, or a mixture of different polymers having such a molecular structure.
[0024] Specific examples of component (A) include compounds represented by the general formulas (i) to (v) shown below.
[0025] (i) (ii) (iii) (iv) (v) In formulas (i) to (v) above, R independently represents a substituted or unsubstituted monovalent hydrocarbon group bonded to a silicon atom, excluding alkenyl groups as described above, and preferably methyl or phenyl. In formulas (i) to (v), n is an integer from 0 to 5000, m is an integer from 5 to 5000, and the sum of n and m is in the range of 5 to 10000. In some embodiments, n is in the range from as low as 0, 10, 50, 100, 200, 500 and as high as 1000, 2000, 5000, or any range defined between any two of the aforementioned values; and m is in the range from 5, 10, 50, 200, or as high as 500, 1000, 2000, 5000, or any range defined between any two of the aforementioned values. Furthermore, the sum of n and m is in the range of 5, 10, 30, 50, 100, 200, 500, or 1000, 2000, 5000, 10000, or any range between any two of the aforementioned values, such as 10 to 10000 and 1000 to 5000.
[0026] In some embodiments, the unsubstituted or substituted monovalent hydrocarbon groups R in formulas (i) to (v) above are each independently selected from straight-chain alkyl groups, preferably from methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, n-decyl, n-undecyl, n-dodecyl, n-tridecyl, n-tetradecyl, n-pentadecanyl, n-hexadecyl, n-heptadecyl, n-octadecyl, n-nonadecanyl, and n-eicosyl; branched alkyl groups are preferably selected from isopropyl... The alkyl group comprises tert-butyl, isobutyl, 2-methylundecyl, and 1-hexylheptyl; cyclic alkyl groups, preferably selected from cyclopentyl, cyclohexyl, and cyclododecyl; aryl groups, preferably selected from phenyl, tolyl, and xylyl; aralkyl groups, preferably selected from benzyl, phenethyl, and 2-(2,4,6-trimethylphenyl)propyl; and haloalkyl groups, preferably selected from 3,3,3-trifluoropropyl and 3-chloropropyl; preferably selected from linear alkyl groups and aryl groups; and more preferably selected from methyl, ethyl, and phenyl groups.
[0027] In a preferred embodiment, component (A) is selected from vinyl-terminated polydimethylsiloxane, vinyl-terminated diphenylsiloxane-dimethylsiloxane copolymer, vinyl-terminated polyphenylsiloxane, vinyl-benzyl-terminated vinylphenylsiloxane-phenylmethylsiloxane copolymer, vinyl-terminated trifluoropropylmethylsiloxane-dimethylsiloxane copolymer, vinyl-terminated diethylsiloxane-dimethylsiloxane copolymer, vinylmethylsiloxane-dimethylsiloxane copolymer, trimethylsilyl-terminated vinylmethylsiloxane-dimethylsiloxane copolymer, and silanol-terminated... Vinylmethylsiloxane-dimethylsiloxane copolymers, vinylmethylsiloxane homopolymers, vinylmethylsiloxane copolymers, vinyl-terminated poly(methylsiloxane) copolymers, vinyl-terminated poly(methylsiloxane) copolymers, vinyl-terminated poly(methylsiloxane) copolymers, poly(vinyl-terminated poly(methylsiloxane) copolymers, poly(vinyl-terminated poly(vinylsiloxane) and poly(vinylsiloxane) copolymers, monovinyl-terminated polydimethylsiloxane, vinylmethylsiloxane terpolymers, vinylmethoxysilane homopolymers, or combinations thereof.
[0028] There is no particular limitation on the molecular weight of component (A), and it is preferably in the range of 3,000 to 20,000 g / mol.
[0029] Component (A) may be used alone or in combination of two or more different compounds.
[0030] These alkenyl-containing organopolysiloxanes used as component (A) can be prepared using conventionally known methods. In typical preparation methods, alkenyl-containing organopolysiloxanes are prepared by subjecting an organic cyclic oligomeric siloxane to a hexaorganodisiloxane in the presence of either a base catalyst or an acid catalyst in an equilibrium reaction.
[0031] Preferably, component (A) is a vinyl-terminated polydimethylsiloxane with a viscosity of less than 200 mPa·s at 25°C.
[0032] Examples of commercially available products of component (A) include, but are not limited to, vinyl-terminated polydimethylsiloxanes RHVi392, RH Vi393, RH Vi395, RH Vi321, RH Vi322, RH Vi311, RH Vi305, RH Vi70E, RHVi100E, RH Vi500E, and RH Vi1000E, all of which are available from Zhejiang Runhe Chemical New Material Co., Ltd.; and Andisil TM VS 20, Andisil TM VS 50, Andisil TM VS 100, Andisil TM VS 200, Andisil TM VS 500 and Andisil TM VS 100, all of which are available from AB Specialty Silicones. Preferably, component (A) is selected from RH Vi 393, RH Vi70E and RH Vi100E, all of which are available from Zhejiang Runhe Chemical New Materials Co., Ltd. More preferably, component (A) is RH Vi100E available from Zhejiang Runhe Chemical New Materials Co., Ltd.
[0033] Preferably, component (A) is present in an amount of 0.01 to 5% by weight, preferably 1 to 4% by weight, more preferably 2 to 3.5% by weight, and even more preferably 2.5 to 3% by weight, based on the total weight of the composition.
[0034] (B) Alkyl-terminated organopolysiloxanes According to the present invention, the thermally conductive silicone adhesive composition comprises (B) alkyl-terminated organopolysiloxane.
[0035] As used herein, “alkyl” refers to a straight-chain or branched hydrocarbon group having 1 to 5 carbon atoms (“C…”). 1-5 Alkyl groups, such as methyl, ethyl, propyl, butyl, and pentyl.
[0036] Preferably, the alkyl-terminated organopolysiloxane can be an alkyl-terminated polydimethylsiloxane, and more preferably a methyl-terminated polydimethylsiloxane.
[0037] In some embodiments, the viscosity of component (B) at 25°C is less than 1000 mPa·s, preferably less than 500 mPa·s, and more preferably less than 200 mPa·s. The viscosity described herein was measured using a TA rheometer with a parallel plate and a 25 mm rotor at 60 rpm and 25°C.
[0038] Preferably, component (B) is a methyl-terminated polydimethylsiloxane with a viscosity of less than 200 mPa·s at 25°C.
[0039] Examples of commercially available products of component (B) include, but are not limited to: RH201-20, RH201-50, and RH201-100, all of which are available from Zhejiang Runhe Chemical New Materials Co., Ltd.; H201-20, H201-50, and H201-100, all of which are available from AB Specialty Silicones; and H201-20, H201-50, and H201-100, all of which are available from Sinopharm. Preferably, component (B) is H201-50, which is available from Sinopharm.
[0040] Preferably, component (B) is present in an amount of 0.01 to 5% by weight, preferably 1 to 4% by weight, more preferably 2 to 3.5% by weight, and even more preferably 2.5 to 3.1% by weight, based on the total weight of the composition.
[0041] (C) Silane coupling agent According to the present invention, the thermally conductive silicone adhesive composition comprises (C) a silane coupling agent.
[0042] Preferably, the silane coupling agent (C) is selected from the following general formulas (I) to (III) and mixtures thereof: In each of the formulas, R1 independently represents hydrogen or vinyl, and R2 independently represents an alkyl group having 1 to 4 carbon atoms. In a preferred embodiment of the invention, R1 independently represents hydrogen; and / or R2 independently represents methyl. In another preferred embodiment of the invention, component (C) is a silane coupling agent represented by formula (I).
[0043] Examples of silane coupling agents used in this invention include, but are not limited to, trimethoxysilane, dimethoxy(methyl)silane, dimethoxy(ethyl)silane, dimethoxy(propyl)silane, dimethoxy(butyl)silane, vinyltrimethoxysilane, vinyltriethoxysilane, and vinyldimethoxy(methyl)silane. Preferably, the silane coupling agent is trimethoxysilane.
[0044] Examples of commercially available products of component (C) include, but are not limited to: trimethoxysilanes available from Sinopharm Group, TCI, and Sigma-aldrich; dimethoxy(methyl)silanes available from Sinopharm Group, TCI, and Sigma-aldrich; dimethoxymethylvinylsilanes available from Sinopharm Group, TCI, Sigma-aldrich, Momentive, and Wacker, such as Silquest A 2171 available from Momentive and Geniosil XL 12 available from Wacker; and vinyltrimethoxysilanes available from Sinopharm Group, TCI, Sigma-aldrich, Momentive, Wacker, and Evonik, such as Silquest A 171 available from Momentive, Geniosil XL 10 available from Wacker, and Dynasylan VTMO available from Evonik. Preferably, component (C) is a trimethoxysilane available from Sinopharm Group.
[0045] Preferably, each component (C) is present in an amount of 0.01 to 0.9% by weight, preferably 0.05 to 0.5% by weight, more preferably 0.07 to 0.2% by weight, and even more preferably 0.08 to 0.11% by weight, based on the total weight of the composition.
[0046] (D) Catalyst According to the present invention, the thermally conductive silicone adhesive composition contains (D) a catalyst.
[0047] Preferably, a catalyst known as a catalyst used in the hydrosilylation reaction can be used. In a preferred embodiment of the invention, component (D) is a platinum-based catalyst. Examples of commercially available Pt catalysts include, but are not limited to, those available from Evonik, Gelest, and Nusil. Preferably, component (D) is Pt catalyst 540 available from Evonik, having a Pt ratio of 0.2% by weight.
[0048] Preferably, each component (D) is present in an amount of 0.0005 to 0.1% by weight, and more preferably 0.001 to 0.05% by weight, based on the total weight of the composition.
[0049] (E) A mixture of components (e-1), (e-2) and (e-3) According to the present invention, the thermally conductive silicone adhesive composition comprises (E)(e-1)D 50 Alumina with a particle size of 4 to 8 μm, (e-2)D 50 Silicon carbide with a particle size of 1 to 4 μm and (e-3)D 50 A mixture of alumina and / or zinc oxide with a particle size of less than 1 μm.
[0050] (e-1)D 50 Alumina with a particle size of 4 to 8 μm In a preferred embodiment of the invention, the D of component (e-1) 50 The particle size is 4.5 to 7 μm, preferably 5 to 6 μm, and more preferably 5 μm.
[0051] Examples of commercially available components (e-1) include, but are not limited to: AA-5, available from Sumitomo, Japan, which is D. 50 Alumina with a particle size of 5 μm; BAK 5 available from Bestry, China; and SFADW 5 available from CMP, China. Preferably, component (e-1) is AA-5 available from Sumitomo, Japan, which is D 50 Alumina with a particle size of 5 μm.
[0052] Preferably, each component (e-1) is present in an amount of 10 to 80% by weight, more preferably 20 to 63% by weight, even more preferably 30 to 55% by weight, and most preferably 34 to 49% by weight, based on the total weight of the composition. In a preferred embodiment of the invention, component (e-1) is present in an amount of 49% by weight, based on the total weight of the composition.
[0053] (e-2)D 50 Silicon carbide with a particle size of 1 to 4 μm In a preferred embodiment of the invention, the D of component (e-2) 50 The particle size is 1.5 to 3.5 μm, preferably 2 to 3 μm, and more preferably 2.5 μm.
[0054] Examples of commercially available components (e-2) include, but are not limited to: SiC 2.5μm available from GNF Graystar (USA), Fiven (Norway), Pacific Rundom (Japan), and Eno Material, Boer Material, and Hongwu Nano (China), which is D 50 Silicon carbide with a particle size of 2.5 μm. Preferably, component (e-2) is SiC 2.5 μm available from Xi'an Boer Materials, which is D 50 Silicon carbide with a particle size of 2.5 μm.
[0055] Preferably, each component (e-2) is present in an amount of 5 to 70% by weight, more preferably 15 to 50% by weight, even more preferably 20 to 45% by weight, and most preferably 25 to 40% by weight, based on the total weight of the composition. In a preferred embodiment of the invention, component (e-2) is present in an amount of 25% by weight, based on the total weight of the composition.
[0056] (e-3)D 50 Alumina and / or zinc oxide with a particle size of less than 1 μm In a preferred embodiment of the invention, the D of component (e-3) 50 The particle size is less than 0.8 μm, preferably less than 0.6 μm, more preferably less than 0.4 μm, and even more preferably 0.3 μm.
[0057] Preferably, the component (e-3) used in this invention is D. 50 Alumina with a particle size of less than 1 μm.
[0058] Examples of commercially available components (e-3) include, but are not limited to: AA-03F, available from Sumitomo, which is D 50 Alumina with a particle size of 0.3 μm; and Zoco 103, which is available from Zochem, is D 50 Zinc oxide with a particle size of 0.3 μm. Preferably, component (e-3) is AA-03F, which is available from Sumitomo and is D. 50 Alumina with a particle size of 0.3 μm.
[0059] Preferably, each component (e-3) is present in an amount of 1 to 40% by weight, more preferably 10 to 30% by weight, and even more preferably 15 to 25% by weight, based on the total weight of the composition. In a preferred embodiment of the invention, component (e-3) is present in an amount of 20% by weight, based on the total weight of the composition.
[0060] In a preferred embodiment of the invention, the thermally conductive silicone adhesive composition according to the invention does not contain fillers other than component (E).
[0061] Optional additives In some embodiments of the invention, the thermally conductive silicone adhesive composition according to the invention may optionally further comprise additives commonly used in the art to which this invention pertains, such as inhibitors, pigments, dyes, fluorescent dyes, heat-resistant additives, flame retardants, plasticizers, adhesive-improving agents, and combinations thereof, provided that they do not negatively affect the desired technical effect of the composition of the invention. The presence, type, and amount of additives can be determined by those skilled in the art based on actual needs.
[0062] The thermally conductive silicone adhesive composition according to the invention can be prepared by any conventional preparation method in the art. Preferably, the composition according to the invention can be prepared by mixing all its components at room temperature in a conventional mixing apparatus (e.g., a planetary mixer or a high-speed mixer).
[0063] The thermally conductive silicone adhesive composition according to the invention can be applied to the desired substrate using any conventional technique. It can be applied cold or warm, if desired. It can be applied to the substrate by extrusion or coating, or by other mechanical application methods such as a caulking gun. Typically, the thermally conductive silicone adhesive composition of the invention is applied to one surface of a pair of substrates, and then the substrates are brought into contact with each other to bond them together. After application, the thermally conductive silicone adhesive composition of the invention cures at room temperature, optionally subsequently at an elevated temperature.
[0064] In a second aspect, this disclosure relates to the cured product of a thermally conductive silicone adhesive composition according to the invention.
[0065] In a third aspect, this disclosure relates to the use of thermally conductive silicone adhesive compositions or cured products according to the invention in the manufacture of electronic devices, particularly in insulated gate bipolar transistor (IGBT) power modules, and in telecommunications and data communication equipment such as 5G base stations.
[0066] Exemplary electronic devices include: computers and computer equipment, such as telecommunications and data communication equipment (e.g., 5G base stations); printers, fax machines, scanners, keyboards, etc.; medical sensors; automotive sensors, etc.; wearable electronic devices (e.g., watches and glasses) and their integrated circuit components; handheld electronic devices (e.g., mobile phones (cellular phones and cellular smartphones) and their integrated circuit components, cameras, tablets, e-readers, monitors (e.g., those used in hospitals, and monitors for healthcare workers, athletes, and individuals), watches, calculators, mice, touchpads, and game joysticks); computers (e.g., desktop and laptop computers) and their integrated circuit components, computer monitors, televisions, media players, household appliances (e.g., refrigerators, washing machines, dryers, ovens, and microwave ovens), light bulbs (e.g., incandescent bulbs, LED bulbs, and fluorescent bulbs), and articles including visible light transparent or transparent parts, glass housing structures, and protective transparent covers for displays or other optical components.
[0067] The thermally conductive silicone adhesive composition according to the invention—which utilizes a specific combination of components (A) to (E), particularly a specific combination of components (e-1), (e-2), and (e-3)—exhibits low thermal resistance, low viscosity suitable for printing processes, high breakdown voltage, and good anti-pumping properties; and in particular, it simultaneously exhibits a temperature below 0.06 K·cm⁻¹. 2 Thermal resistance of / W, viscosity at 25°C of 100 to 300 Pa·s, breakdown voltage above 3 kV / mm, and good anti-pumping performance for 200 cycles at -40 to 125°C.
[0068] Example The following examples are intended to help those skilled in the art better understand and implement this disclosure. The scope of the invention is not limited by the examples, but is defined by the appended claims. Unless otherwise stated, all parts and percentages are based on weight.
[0069] Raw materials: Component (A): Component a: RH Vi100E, which is a vinyl-terminated polydimethylsiloxane with a viscosity of 100 mPa·s, available from Zhejiang Runhe Chemical New Materials Co., Ltd.
[0070] Component (B): Component b: H2O1-50, which is a methyl-terminated polydimethylsiloxane with a viscosity of 50 mPa·s, available from Sinopharm Group.
[0071] Component (C): Component c: Trimethoxysilane, which has The chemical structure of [the substance] can be obtained from Sinopharm Group.
[0072] Component (D): Component d: Pt catalyst 540, which has a Pt ratio of 0.2% by weight, is available from Evonik.
[0073] Component (E): Component (e-1): Component e-1-1: AA-5, which is D 50 Alumina with a particle size of 5 μm can be obtained from Sumitomo.
[0074] Component e-1-2': BAK-10, which is D 50 Alumina with a particle size of 10 μm can be obtained from Bestry.
[0075] Component (e-2): Component e-2-1: SiC 2.5μm, which is D50 Silicon carbide with a particle size of 2.5 μm can be obtained from Xi'an Boer Materials.
[0076] Component e-2-2': SiC 5μm, which is D 50 Silicon carbide with a particle size of 5 μm can be obtained from Bohr Materials.
[0077] Component e-2-3': SiC 20μm, which is D 50 Silicon carbide with a particle size of 20 μm can be obtained from Bohr Materials.
[0078] Component e-2-4': FB-72F, which is D 50 Zinc oxide with a particle size of 1 μm is available from Guangdong Jinge Material Co., Ltd.
[0079] Component e-2-5': AA-3, which is D 50 Alumina with a particle size of 3 μm can be obtained from Sumitomo.
[0080] Component (e-3): Component e-3-1: AA-03F, which is D 50 Alumina with a particle size of 0.3 μm can be obtained from Sumitomo.
[0081] Component e-3-2: Zoco 103, which is D 50 Zinc oxide with a particle size of 0.3 μm can be obtained from Zochem.
[0082] Preparation of Examples 1 to 9 (Ex.1 to Ex.9) The specific amounts and types of each component in the thermally conductive silicone adhesive compositions of Examples 1 to 9 are shown in Tables 1 and 2. The compositions were prepared as follows: all components were mixed for 1 hour in a planetary mixer at a paddle speed of 30 RPM using a high-shear distributor at a speed of 800 RPM, during which a vacuum was applied to eliminate air bubbles in the mixture at 0.1 MPa. The mixing equipment used was a 1.5L ROSS mixer manufactured by Charles Ross & Son Company.
[0083] Test method: thermal resistance For each of the compositions from Ex.1 to Ex.9, the thermal resistance was tested at 40 psi and 80 °C using a Longwin 9389 from Long Win Science and Technology Corporation, in accordance with standard ASTM D5470.
[0084] In this invention, the thermal resistance exhibited is less than 0.06 K·cm. 2 A thermally conductive silicone adhesive composition with a value of / W is desirable, and the lower the better.
[0085] Viscosity at 25°C For each of the compositions from Ex.1 to Ex.9, the viscosity was measured at 25°C using a TA rheometer DHR20 with a parallel plate of 25 mm, a shear rate of 10 / s, and a gap of 0.5 mm, in accordance with ASTM D4092.
[0086] In this invention, a thermally conductive silicone adhesive composition exhibiting a viscosity of 100 to 300 Pa·s at 25°C is desirable.
[0087] Breakdown voltage For each of the compositions from Ex.1 to Ex.9, the breakdown voltage was measured according to ASTM 149 using a Hipot tester from Electrom Instruments, with a sample thickness of 1 mm.
[0088] In this invention, thermally conductive silicone adhesive compositions exhibiting a breakdown voltage higher than 3 kV / mm are desirable, and the higher the better.
[0089] Anti-pumping performance For each of the compositions Ex.1 to Ex.9, the composition was printed on an aluminum substrate with a stencil mesh at a thickness of 0.1 mm. An IGBT module with a Ni-coated copper plate was assembled to the substrate with a screw force of 5 Nm. The module was then placed in a thermal cycling oven for 200 cycles at -40 to 125°C. After thermal cycling aging, the anti-pumping performance was visually inspected. In particular, the composition was evaluated as "fail" when the surface had a void content equal to or greater than 30%; "pass" when the surface had a void content less than 30% but greater than 10%; and "good" when the surface had a void content equal to or less than 10%.
[0090] In this invention, a thermally conductive silicone adhesive composition exhibiting good anti-pumping properties is desirable.
[0091] The thermal resistance, viscosity, breakdown voltage, and anti-pumping properties of the composition were tested using the methods described above, and the results are shown in Tables 1 and 2.
[0092] Table 1
[0093] Table 2
[0094] From the data in Tables 1 and 2, it can be seen that the thermally conductive silicone adhesive compositions (Ex.1, Ex.7, and Ex.9) according to the present invention—which utilize specific combinations of components (A) to (E), especially specific combinations of components (e-1), (e-2), and (e-3)—exhibit low thermal resistance, low viscosity suitable for printing processes, high breakdown voltage, and good anti-pumping properties; and in particular, they simultaneously exhibit a value below 0.06 K·cm⁻¹. 2 The thermal resistance is / W, the viscosity at 25°C is 100 to 300 Pa·s, the breakdown voltage is higher than 3 kV / mm, and the anti-pumping performance is good for 200 cycles at -40 to 125°C. Furthermore, by comparing Ex.1 with Ex.9, it can be seen that alumina is preferred over zinc oxide as component (e-3); and by comparing Ex.1 with Ex.7, it can be seen that the thermally conductive silicone adhesive composition according to the invention in which the content of component (e-1) is higher than the content of component (e-2) exhibits better desired performance than the thermally conductive silicone adhesive composition according to the invention in which the content of component (e-1) is lower than the content of component (e-2).
[0095] In contrast, the thermally conductive silicone adhesive compositions not according to the invention (Ex.2 to Ex.6 and Ex.8) did not simultaneously exhibit a temperature below 0.06 K·cm. 2 Thermal resistance of / W, viscosity at 25°C of 100 to 300 Pa·s, breakdown voltage above 3 kV / mm, and good anti-pumping properties for 200 cycles at -40 to 125°C. For example, Ex.2 to 3 (which contain zinc oxide or aluminum oxide as a substitute for component (e-2)) and Ex.4 to 5 (which contain D 50 SiC substitutes (e-2) with particle sizes of 20 or 5 μm both exhibited a Kcm value higher than 0.06. 2 With a thermal resistance of / W, Ex.4 exhibits a viscosity of less than 100 Pa·s at 25°C and a breakdown voltage of less than 3 kV / mm, while Ex.3 and Ex.4 do not exhibit good anti-pumping performance in 200 cycles from -40 to 125°C. Ex.6 (which contains D in addition to component (E)) 50 Alumina with a particle size of 3 μm exhibits a K·cm⁻¹ > 0.06 K·cm⁻¹. 2 / W thermal resistance and did not exhibit good anti-pumping performance for 200 cycles at -40 to 125°C. Ex.8 (which contains D 50The alumina substitute component (e-1) with a particle size of 10 μm exhibited a value higher than 0.06 K·cm⁻¹. 2 The thermal resistance was / W and the viscosity at 25°C did not show a range of 100 to 300 Pa·s.
[0096] Although some preferred embodiments have been described, various modifications and variations can be made to them in light of the foregoing teachings. Therefore, it should be understood that the invention can be practiced in ways different from those specifically described without departing from the scope of the appended claims.
Claims
1. A thermally conductive silicone adhesive composition, said thermally conductive silicone adhesive composition comprising: (A) Alkenyl-containing organopolysiloxanes; (B) Alkyl-terminated organopolysiloxanes; (C) Silane coupling agent; (D) Catalyst; and (E)(e-1)D 50 Alumina with a particle size of 4 to 8 μm, (e-2)D 50 Silicon carbide with a particle size of 1 to 4 μm and (e-3)D 50 A mixture of alumina and / or zinc oxide with a particle size of less than 1 μm.
2. The thermally conductive silicone adhesive composition according to claim 1, wherein the D of component (e-1) 50 The particle size is 4.5 to 7 μm, preferably 5 to 6 μm, and more preferably 5 μm.
3. The thermally conductive silicone adhesive composition according to claim 1 or 2, wherein the D of component (e-2) 50 The particle size is 1.5 to 3.5 μm, preferably 2 to 3 μm, and more preferably 2.5 μm.
4. The thermally conductive silicone adhesive composition according to any one of claims 1 to 3, wherein the D of component (e-3) 50 The particle size is less than 0.8 μm, preferably less than 0.6 μm, more preferably less than 0.4 μm, and even more preferably 0.3 μm.
5. The thermally conductive silicone adhesive composition according to any one of claims 1 to 4, wherein it does not contain fillers other than component (E).
6. The thermally conductive silicone adhesive composition according to any one of claims 1 to 5, wherein each component (e-1) is present in an amount of 10 to 80% by weight, more preferably 20 to 63% by weight, and even more preferably 30 to 55% by weight, based on the total weight of the composition.
7. The thermally conductive silicone adhesive composition according to any one of claims 1 to 6, wherein each component (e-2) is present in an amount of 5 to 70% by weight, more preferably 15 to 50% by weight, and even more preferably 20 to 45% by weight, based on the total weight of the composition.
8. The thermally conductive silicone adhesive composition according to any one of claims 1 to 7, wherein each component (e-3) is present in an amount of 1 to 40% by weight, more preferably 10 to 30% by weight, and even more preferably 15 to 25% by weight, based on the total weight of the composition.
9. The thermally conductive silicone adhesive composition according to any one of claims 1 to 8, wherein component (A) is a vinyl-terminated polydimethylsiloxane with a viscosity of less than 200 mPa·s at 25°C.
10. The thermally conductive silicone adhesive composition according to any one of claims 1 to 9, wherein component (B) is a methyl-terminated polydimethylsiloxane with a viscosity of less than 200 mPa·s at 25°C.
11. The thermally conductive silicone adhesive composition according to any one of claims 1 to 10, wherein component (C) is trimethoxysilane.
12. The thermally conductive silicone adhesive composition according to any one of claims 1 to 11, wherein component (D) is a platinum-based catalyst.
13. The cured product of the thermally conductive silicone adhesive composition according to any one of claims 1 to 12.
14. Use of the thermally conductive silicone adhesive composition according to any one of claims 1 to 12 or the cured product according to claim 13 in the manufacture of electronic devices, particularly in insulated gate bipolar transistor (IGBT) power modules and telecommunications and data communication equipment such as 5G base stations.