Insulation heat conduction material, preparation method and application thereof, radiator and power assembly

Abstract

The invention discloses an insulating heat-conducting material, a preparation method and application thereof, a radiator and a power component, and relates to the technical field of electronic products, the insulating heat-conducting material comprises the following components by weight: 80-95 parts of an insulating heat-conducting filler, 3-15 parts of an epoxy monomer, 1-5 parts of an active diluent, and 0.2-4 parts of a curing agent. According to the insulating and heat-conducting material, the epoxy monomer with low viscosity is selected to be matched with the reactive diluent, so that the overall viscosity of the material can be reduced, the dispersity of the insulating and heat-conducting filler is improved, and the phenomenon that the viscosity of a formed coating is too high is avoided. In addition, the insulating heat-conducting material does not contain an organic solvent, so that the problem of viscosity increase caused by volatilization of the organic solvent can be avoided in application. Therefore, an insulating heat-conducting coating formed by the insulating heat-conducting material has the service life of 15-20 years, and the service life of the coating can be remarkably prolonged.

Description

Technical Field

[0001] The present invention relates to the technical field of electronic products, and in particular to an insulating thermally conductive material, a preparation method and application thereof, a radiator and a power component. Background Art

[0002] High-voltage power devices generate a lot of heat during operation, so additional metal heat sinks are needed for heat dissipation. In order to avoid short circuits between non-insulated high-voltage power devices and metal heat sinks, insulation measures must usually be added between them. Common insulation measures include: setting a ceramic substrate and silicone grease on the heat sink casing; setting a thermally conductive insulating film on the heat sink casing; setting a metal substrate and silicone grease on the heat sink casing, etc., but there are problems such as high cost and complex assembly.

[0003] There is also a method in the related art of coating a high thermal conductivity composite resin on the surface of electronic components or the surface of a circuit board of an electronic product to form a heat dissipation coating. However, during the application process, the coating will have a problem of reduced service life due to increased viscosity. Summary of the invention

[0004] The main purpose of the present invention is to provide an insulating thermally conductive material and a preparation method and application thereof, a heat sink and a power component, aiming to solve the problem of low service life caused by increased viscosity during the application of existing high thermal conductivity composite resins.

[0005] To achieve the above object, the insulating thermally conductive material proposed by the present invention comprises the following components in parts by weight:

[0006] 80-95 parts of insulating thermal conductive filler, 3-15 parts of epoxy monomer, 1-5 parts of active diluent, and 0.2-4 parts of curing agent.

[0007] In one embodiment, the insulating thermally conductive filler is selected from at least one of aluminum oxide, aluminum hydroxide, aluminum nitride, boron nitride, silicon carbide, and silicon dioxide.

[0008] In one embodiment, the insulating thermally conductive filler has a spherical shape, and the particle size D of the insulating thermally conductive filler is 50 0.001μm~30μm.

[0009] In one embodiment, the insulating thermally conductive filler is composed of a first powder, a second powder and a third powder;

[0010] The particle size D of the first powder 50 5 μm to 30 μm; and / or the particle size D of the second powder 50 0.1 μm to 5 μm; and / or the particle size D of the third powder 50 It is 0.001μm~0.1μm.

[0011] In one embodiment, the mass ratio of the first powder, the second powder, and the third powder is (1-2.5):1:(0.01-0.5).

[0012] In one embodiment, the epoxy monomer is selected from at least one of bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, phenyl diglycidyl ether, naphthyl diglycidyl ether, and glycerol triglycidyl ether.

[0013] In one embodiment, the active diluent is selected from at least one of monoglycerol ether, diglycerol ether and triglycerol ether.

[0014] In one embodiment, the reactive diluent is selected from at least one of butyl glycidyl ether, butanediol diglycidyl ether, neopentyl glycol diglycidyl ether, hexanediol diglycidyl ether, polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether and glycerol triglycidyl ether.

[0015] In one embodiment, the curing agent is selected from at least one of anhydride curing agents, amine curing agents, and imidazole curing agents.

[0016] In one embodiment, the curing agent is selected from at least one of methylhexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylnadic anhydride, polyetheramine D230, dicyandiamide, 2-heptadecylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 1-benzyl-2-methylimidazole, 1-benzyl-2-ethylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, and 1-cyanoethyl-2-undecylimidazole.

[0017] In one embodiment, the insulating thermally conductive material further comprises 0.01 to 0.5 parts by weight of a defoaming agent.

[0018] The present invention also provides a method for preparing an insulating thermally conductive material, comprising the following steps:

[0019] Mix 3-15 parts by weight of epoxy monomer, 1-5 parts by weight of active diluent, and 0.2-4 parts by weight of curing agent, and dissolve and stir to obtain a mixed solution;

[0020] 80-95 parts by weight of insulating thermal conductive filler is added into the mixed solution and mixed and stirred.

[0021] In one embodiment, the parameters of the dissolving stirring are: a rotation speed of 1000 rpm to 3000 rpm, and a time of 1 min to 8 min; and / or, the parameters of the mixing stirring are: a rotation speed of 100 rpm to 1500 rpm, and a time of 0.4 min to 12 min.

[0022] In one embodiment, the mixing and stirring is divided into four stages, the rotation speed of the first stage is 100rpm~700rpm, and the time is 0.1min~3min; the rotation speed of the second stage is 700rpm~1300rpm, and the time is 0.1min~3min; the rotation speed of the third stage is 1300rpm~2500rpm, and the time is 0.1~3min; the rotation speed of the fourth stage is 700~1500rpm, and the time is 0.1~3min.

[0023] In one embodiment, the method for preparing the insulating thermally conductive material further comprises a degassing and stirring step, and the parameters of the degassing and stirring are: a rotation speed of 1000 rpm to 3000 rpm, a time of 1 min to 8 min, and a vacuum degree of (-90 kPa) to (-100 kPa).

[0024] In one embodiment, the method for preparing the insulating thermally conductive material further comprises adding 0.01 to 0.5 parts by weight of a defoaming agent before dissolving and stirring to obtain the mixed solution.

[0025] The present invention also proposes the use of the insulating thermally conductive material or the insulating thermally conductive material prepared by the preparation method in electronic products.

[0026] In one embodiment, an insulating thermally conductive material is coated or screen-printed on at least a portion of the surface of a heat-generating element in an electronic product, and the insulating thermally conductive coating is formed after curing.

[0027] The present invention also provides a heat sink, comprising a heat sink body and an insulating thermally conductive coating disposed on a surface of one side of the heat sink body, wherein the insulating thermally conductive coating is formed by the above-mentioned insulating thermally conductive material or the insulating thermally conductive material prepared by the above-mentioned preparation method.

[0028] In one embodiment, the thickness of the insulating thermal conductive coating is 80 μm to 120 μm.

[0029] The present invention further provides a power component, comprising a power device and the above-mentioned heat sink, wherein the power device is arranged in contact with the insulating thermal conductive coating.

[0030] In one embodiment, the power device is fixed to the heat sink by a fastener, or the power device is bonded to the heat sink by an insulating thermal conductive coating.

[0031] The insulating thermally conductive material proposed by the present invention includes an insulating thermally conductive filler, an epoxy monomer, a reactive diluent and a curing agent. The low-viscosity epoxy monomer is selected to cooperate with the reactive diluent to reduce the overall viscosity of the material and improve the dispersibility of the insulating thermally conductive filler, so that the viscosity of the formed coating can be avoided to be too high during application. In addition, the insulating thermally conductive material of the present invention does not contain an organic solvent, and the problem of increased viscosity due to the volatilization of the organic solvent can also be avoided during application. Therefore, when the insulating thermally conductive material of the present invention forms an insulating thermally conductive coating, the service life of the coating can be increased. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on the structures shown in these accompanying drawings without paying any creative work.

[0033] Figure 1 It is a structural schematic diagram of a radiator in one embodiment of the present invention;

[0034] Figure 2 This is a flow chart of preparing an insulating thermally conductive material in one embodiment of the present invention;

[0035] Figure 3 A schematic diagram of the structure of a power component in one embodiment of the present invention;

[0036] Figure 4 It is a schematic diagram of the structure of a power component in another embodiment of the present invention;

[0037] Figure 5 It is a schematic diagram of the structure of a power component in another embodiment of the present invention;

[0038] Figure 6 This is a schematic diagram of the structure of a power component in yet another embodiment of the present invention;

[0039] Figure 7 It is a schematic diagram of the structure of the power component in other embodiments of the present invention.

[0040] Description of Figure Numbers

[0041] 100, radiator; 101, radiator body; 102, insulating thermal conductive coating; 103, thermal conductive gel layer;

[0042] 200. Power devices;

[0043] 300, fastener; 301, pressure strip; 302, screw;

[0044] 400, PCB board; 401, thermal via. DETAILED DESCRIPTION

[0045] It should be noted that if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or suggesting their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features specified as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, if "and / or" or "and / or" appears in the full text, its meaning includes three parallel schemes. Taking "A and / or B" as an example, it includes scheme A, or scheme B, or a scheme in which A and B are satisfied at the same time. "At least one" appearing in the embodiments of the present invention refers to one or more, and "more than one" refers to two or more.

[0046] The "range" disclosed in the present invention is defined in the form of a lower limit and an upper limit, and a given range is defined by selecting a lower limit and an upper limit, and the selected lower limit and upper limit define the boundaries of a particular range. The range defined in this way can be inclusive or exclusive of the end values, and can be arbitrarily combined, that is, any lower limit can be combined with any upper limit to form a range. For example, if a range of 60 to 120 and 80 to 110 is listed for a particular parameter, it is understood that a range of 60 to 110 and 80 to 120 is also expected. In addition, if the minimum range values ​​1 and 2 are listed, and if the maximum range values ​​3, 4 and 5 are listed, the following ranges can all be expected: 1 to 3, 1 to 4, 1 to 5, 2 to 3, 2 to 4 and 2 to 5. In the present invention, unless otherwise specified, the numerical range "a to b" represents an abbreviation of any real number combination between a and b, wherein a and b are both real numbers. For example, the numerical range "0-5" means that all real numbers between "0-5" are listed in this document, and "0-5" is just an abbreviation of these numerical combinations. In addition, when a parameter is expressed as an integer ≥ 2, it is equivalent to disclosing that the parameter is, for example, an integer of 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0047] In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the fact that ordinary technicians in the field can implement it. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0048] In order to avoid short circuit between high-voltage power devices and metal heat sinks, it is usually necessary to add insulation measures between them. Commonly used insulation measures are as follows.

[0049] The ceramic substrate and silicone grease are arranged on the housing of the heat sink to transfer the heat generated by the high-voltage power device to the heat sink for discharge through the silicone grease thermal conductive material, and the high-voltage power device and the metal heat sink are insulated by the ceramic substrate. This method is complex to assemble, and the ceramic substrate is a brittle material, which is easy to crack during the assembly process, resulting in insulation failure.

[0050] A thermally conductive insulating film is provided on the casing of the radiator, which needs to be manually assembled and is prone to defects such as bubbles and wrinkles. Moreover, the insulating material of the thermally conductive insulating film is polyimide, which has poor thermal conductivity and cannot quickly transfer heat to the radiator. In addition, the thermally conductive insulating film is easily punctured, resulting in insulation failure.

[0051] Setting a metal substrate on the heat sink casing means welding the high-voltage power device on the metal substrate, and heat conduction between the metal substrate and the metal heat sink is achieved through silicone grease. However, the metal substrate is expensive, the processing is complicated, and the welding process involves high temperatures, which places certain restrictions on the plastic packaging materials of the high-voltage power device.

[0052] In order to achieve heat dissipation of electronic components in the related art, there is also a method of coating a high thermal conductivity composite resin on the surface of electronic components or the surface of electronic product circuit boards to form a heat dissipation coating. However, the high thermal conductivity composite resin is added with an organic solvent, and during the application process, the service life will be reduced due to the increase in solvent evaporation viscosity.

[0053] To this end, the present invention provides an insulating thermally conductive material comprising the following components in parts by weight:

[0054] 80-95 parts of insulating thermal conductive filler, 3-15 parts of epoxy monomer, 1-5 parts of active diluent, and 0.2-4 parts of curing agent.

[0055] Insulating thermally conductive filler refers to a material with high thermal conductivity and electrical insulation. The insulating thermally conductive material of the present invention includes a relatively high content of insulating thermally conductive filler, which can obtain higher thermal conductivity, thereby making it suitable for high-power and high-heat scenarios such as high-voltage power devices.

[0056] Epoxy monomer refers to a monomer compound containing at least two epoxy groups, and is the basic raw material for preparing epoxy resin and related polymers. Reactive diluent refers to a chemical substance used to adjust the viscosity of the system, and in the present invention, it refers to a low molecular weight compound containing epoxy groups. The present invention selects low-viscosity epoxy monomers and reactive diluents to cooperate, which is beneficial to reduce the overall viscosity of the material without introducing volatile solvents, and the reactive diluent itself can be cured into the material network, and will not plasticize the material like a solvent.

[0057] The insulating thermally conductive material of the present invention contains a relatively high content of insulating thermally conductive filler powder. The high powder content will cause problems such as agglomeration, oil-powder separation, and excessive viscosity, which will in turn cause defects such as incomplete coating and uneven thickness, thereby leading to insulation failure. Therefore, on the basis of a high content of insulating thermally conductive filler, the present invention selects a low-viscosity epoxy monomer and a reactive diluent to improve the dispersibility of the insulating thermally conductive filler. The insulating thermally conductive material formed has a relatively low overall viscosity and does not contain an organic solvent, which can avoid the problem of increased viscosity due to the volatilization of organic solvents during application. Therefore, when the insulating thermally conductive material of the present invention forms an insulating thermally conductive coating, the service life of the coating can be increased.

[0058] In an embodiment of the present invention, the insulating thermal conductive filler is selected from at least one of aluminum oxide, aluminum hydroxide, aluminum nitride, boron nitride, silicon carbide, and silicon dioxide. Preferably, it is selected from at least one of aluminum oxide, aluminum nitride, and boron nitride. Aluminum oxide, aluminum nitride, and boron nitride not only have high thermal conductivity, but also have good electrical insulation performance, and are not affected by the use environment and purity.

[0059] In the embodiment of the present invention, the insulating thermally conductive filler has a spherical shape, and the particle size D of the insulating thermally conductive filler is 50 0.001μm~30μm.

[0060] D 50 The median particle size refers to the particle size corresponding to when the cumulative particle size distribution percentage of the sample reaches 50%, that is, the particle size is greater than D 50 50% of the particles are smaller than D 50 The particles also account for 50%.

[0061] Compared with irregularly shaped fillers, spherical insulating thermal conductive fillers provide better insulation performance at the same addition amount because spherical fillers are easier to distribute evenly, thereby reducing the risk of electric field distortion and electrical breakdown.

[0062] In the embodiment of the present invention, the insulating thermal conductive filler is composed of a first powder, a second powder and a third powder; the particle size D of the first powder is 50 5 μm to 30 μm; and / or the particle size D of the second powder 50 0.1 μm to 5 μm; and / or the particle size D of the third powder 50 It is 0.001μm~0.1μm.

[0063] The first powder is micron-sized, the third powder is nano-sized, and the second powder is between nano-sized and micro-sized. The insulating thermal conductive filler of the present invention is composed of powders of different particle sizes, which can fully fill the gaps between particles, avoid agglomeration between particles, thereby improving fluidity and reducing the viscosity of the material.

[0064] In an embodiment of the present invention, the mass ratio of the first powder, the second powder and the third powder is (1-2.5):1:(0.01-0.5).

[0065] The micron-sized first powder has better dispersibility and is not likely to cause a significant increase in material viscosity. In addition, the micron-sized first powder can improve the hardness and wear resistance of the insulating thermal conductive material. The nano-sized third powder has a larger specific surface area and is more likely to form an effective thermal conductive network or path, which can significantly improve thermal conductivity.

[0066] The nanometer-scale third powder can significantly improve the thermal conductivity, insulation resistance and breakdown strength of the material at a relatively low addition amount. When the third powder is added in too high an amount, it is easy to agglomerate and affect its dispersion uniformity. Adding more micrometer-scale first powder is to facilitate uniform dispersion of the insulating and thermally conductive filler and to ensure the mechanical properties of the material when it forms a coating.

[0067] In an embodiment of the present invention, the epoxy monomer is selected from at least one of bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, phenyl diglycidyl ether, naphthyl diglycidyl ether and glycerol triglycidyl ether.

[0068] In an embodiment of the present invention, the active diluent is selected from at least one of monoglycerol ether, diglycerol ether and triglycerol ether. Glycerol ether is a low molecular weight compound containing epoxy groups and can adjust the viscosity of the system.

[0069] In an embodiment of the present invention, the active diluent is selected from at least one of butyl glycidyl ether, butanediol diglycidyl ether, neopentyl glycol diglycidyl ether, hexanediol diglycidyl ether, polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether and glycerol triglycidyl ether.

[0070] In an embodiment of the present invention, the curing agent is selected from at least one of anhydride curing agents, amine curing agents, and imidazole curing agents. The curing agent is an epoxy resin curing agent and can be selected according to the required performance of the material.

[0071] In an embodiment of the present invention, the curing agent is selected from at least one of methylhexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylnadic anhydride, polyetheramine D230, dicyandiamide, 2-heptadecylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 1-benzyl-2-methylimidazole, 1-benzyl-2-ethylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, and 1-cyanoethyl-2-undecylimidazole.

[0072] In an embodiment of the present invention, the insulating thermally conductive material further comprises 0.01 to 0.5 parts by weight of a defoamer. The addition of the defoamer enables the insulating thermally conductive material of the present invention to have the characteristics of rapid defoaming and leveling, can eliminate bubbles mixed in during the printing process, avoid the risk of bubbles mixed in during the application process, thereby making the coating denser and having better insulation performance, and can improve the inherent defect of the insulating thermally conductive material in that the viscosity increases during high-speed printing, and can ensure that the material has a printing effect of more than 8 hours.

[0073] Exemplarily, the defoamer can be selected from at least one of BYK-A525, BYK-A530, BYK-A555, BYK-057, BYK-066N, and Defom 6800. The defoamer enables the material to have the performance of smooth glue removal and screen release, and is suitable for screen printing process. Even in an open environment at room temperature and after repeated friction with a screen scraper, the insulating thermal conductive material of the present invention can maintain long-lasting operability, that is, the material of the present invention has high compatibility with the screen printing process.

[0074] The present invention also provides a method for preparing an insulating thermally conductive material, comprising the following steps:

[0075] Mix 3 to 15 parts by weight of epoxy monomer, 1 to 5 parts by weight of active diluent, and 0.2 to 4 parts by weight of curing agent, and dissolve and stir to obtain a mixed solution;

[0076] 80 to 95 parts by weight of insulating thermal conductive filler are added into the mixed solution and mixed and stirred.

[0077] In an embodiment of the present invention, the parameters of dissolving and stirring are: rotation speed of 1000 rpm to 3000 rpm, and time of 1 min to 8 min; and / or, the parameters of mixing and stirring are: rotation speed of 100 rpm to 1500 rpm, and time of 0.4 min to 12 min.

[0078] In an embodiment of the present invention, the mixing and stirring is divided into four stages. The rotation speed of the first stage is 100rpm~700rpm, and the time is 0.1min~3min; the rotation speed of the second stage is 700rpm~1300rpm, and the time is 0.1min~3min; the rotation speed of the third stage is 1300rpm~2500rpm, and the time is 0.1~3min; the rotation speed of the fourth stage is 700~1500rpm, and the time is 0.1~3min.

[0079] The present invention adopts a four-stage stirring process, starting with slow stirring to prevent the insulating conductive filler powder with the lowest density from flying out and affecting the actual ratio, and then accelerating the stirring when the insulating thermal conductive filler is immersed in the mixed liquid rubber to mix and evenly disperse it. Since long-term high-speed stirring will cause serious friction heat generation, the stirring speed starts to decrease in the fourth stage.

[0080] It should be noted that the speed and time of the first stage, the speed and time of the second stage, the speed and time of the third stage, and the speed and time of the fourth stage provided in the embodiment of the present invention can be any values ​​that meet the above range values. For example, the speed of the first stage is 700 rpm and the time is 3 minutes.

[0081] In an embodiment of the present invention, the method for preparing the insulating thermally conductive material further includes a degassing and stirring step, and the parameters of the degassing and stirring are: a rotation speed of 1000 rpm to 3000 rpm, a time of 1 min to 8 min, and a vacuum degree of (-90 kpa) to (-100 kpa).

[0082] The present invention degasses and stirs the polarity of the material under vacuum conditions, and can further remove a small amount of volatile matter that may be contained in the raw material, thereby reducing the VOC content and improving the reliability of the material.

[0083] In an embodiment of the present invention, the method for preparing the insulating thermally conductive material further includes mixing 0.01 to 0.5 parts by weight of a defoamer with 3 to 15 parts by weight of an epoxy monomer, 1 to 5 parts by weight of an active diluent and 0.2 to 4 parts by weight of a curing agent, dissolving and stirring to obtain a mixed liquid.

[0084] The present invention also proposes the use of the above insulating thermally conductive material or the insulating thermally conductive material prepared by the above preparation method in electronic products. The insulating thermally conductive material can assist the electronic products in heat dissipation.

[0085] In an embodiment of the present invention, at least a portion of the surface of a heat generating element in an electronic product may be covered with an insulating thermal conductive material, and after curing, an insulating thermal conductive coating is formed. The at least portion of the surface may be a portion of the surface or the entire surface, and the insulating thermal conductive material may be covered by screen printing, spraying, or spin coating.

[0086] The heat generating components include but are not limited to the following components: semiconductor devices (transistors, diodes, thyristors, etc.), resistors, circuit boards, light emitting diodes, etc. The curing method may be heating curing, the heating curing temperature may be 140°C-220°C, and the curing time may be 5min-60min.

[0087] The present invention also proposes a heat sink, comprising a heat sink body and an insulating thermally conductive coating, wherein the insulating thermally conductive coating is arranged on one side surface of the heat sink body, and the insulating thermally conductive coating is formed by the above-mentioned insulating thermally conductive material or the insulating thermally conductive material prepared by the above-mentioned preparation method.

[0088] The radiator body is a metal radiator, and illustratively, it can be an aluminum radiator, a copper radiator, a sheet metal chassis (shell), a metal die-cast chassis (shell), a metal die-cast water channel radiator, a copper heat pipe aluminum radiator, etc.

[0089] In an embodiment of the present invention, the thickness of the insulating thermal conductive coating is 80 μm to 120 μm, which can ensure the electrical insulation strength of the coating.

[0090] The present invention also proposes a power assembly, comprising a power device and the above-mentioned heat sink, wherein the power device is fitted with an insulating thermal conductive coating. In this way, the heat generated by the power device during operation can be quickly transferred to the heat sink for discharge, and the insulating thermal conductive coating can ensure the insulation between the power device and the heat sink. In addition, the insulating thermal conductive coating can be processed by automated equipment, thereby realizing low-cost installation of the power assembly.

[0091] In an embodiment of the present invention, the power device is fixed to the heat sink by a fastener, or the power device is bonded to the heat sink by an insulating thermal conductive coating. Bonding the power device to the heat sink by an insulating thermal conductive coating can reduce the additional fixation of the power device and achieve high-density assembly of the power component.

[0092] The following describes the invention in conjunction with specific embodiments.

[0093] Example 1

[0094] A heat sink 100, with reference to Figure 1 As shown, the heat sink body 101 and the insulating thermal conductive coating 102 are provided on one side surface of the heat sink body 101 (i.e. Figure 1 The thickness of the insulating thermal conductive coating 102 is 80 μm.

[0095] The insulating thermal conductive coating 102 in this embodiment is formed by screen printing an insulating thermal conductive material, and the specific steps are as follows:

[0096] (1) Adjust the distance between the screen and the radiator body, use the screen with the shore A80 rubber scraper, and print the insulating thermal conductive material on the surface of the radiator body at a certain printing speed.

[0097] (2) The printed insulating thermal conductive material is cured at 190° C. for 20 minutes to form an insulating thermal conductive coating. In order to ensure the electrical insulation strength of the insulating thermal conductive coating, a layer of insulating thermal conductive material is printed on the first cured insulating thermal conductive coating and then cured again.

[0098] The insulating thermally conductive material of this embodiment includes the following components:

[0099] The first alumina powder (particle size D 50 10 μm) 51.24 g, the second alumina powder (particle size D 50 2μm) 34.16g, silicon dioxide (particle size D50 12nm) 0.6g, bisphenol F diglycidyl ether 8.4g, 1,6-hexanediol diglycidyl ether 2.4g, polypropylene glycol diglycidyl ether 1.2g, 1-cyanoethyl-2-ethyl-4-methylimidazole 1.8g, defoamer BYK-A5300.2g. That is, in this embodiment, the mass ratio of the first alumina powder, the second alumina powder and silicon dioxide is 1.5:1:0.018, and the mass ratio of the active diluent, the epoxy monomer and the curing agent is 0.429:1:0.214.

[0100] refer to Figure 2 As shown, the insulating thermal conductive material of this embodiment is prepared by the following method:

[0101] (1) 8.4 g of bisphenol F diglycidyl ether, 2.4 g of 1,6-hexanediol diglycidyl ether, 1.2 g of polypropylene glycol diglycidyl ether, 1.8 g of 1-cyanoethyl-2-ethyl-4-methylimidazole, and 0.2 g of defoamer BYK-A530 were mixed and stirred at 1500 rpm for 3 min to obtain a mixed solution.

[0102] (2) Add 51.24 g of the first alumina powder, 34.16 g of the second alumina powder, and 0.6 g of silicon dioxide to the mixed solution and mix them evenly. The mixing and stirring is divided into four stages. The rotation speed of the first stage is 500 rpm and the time is 40 s; the rotation speed of the second stage is 1000 rpm and the time is 1 min; the rotation speed of the third stage is 1500 rpm and the time is 1 min; the rotation speed of the fourth stage is 800 rpm and the time is 40 s.

[0103] (3) The mixture in step (2) was degassed and stirred at a vacuum degree of -98 kPa, a rotation speed of 1500 rpm, and a time of 3 min.

[0104] Example 2

[0105] Different from Example 1, the epoxy monomer in the insulating thermally conductive material of this example uses 8.4 g of bisphenol A diglycidyl ether.

[0106] Example 3

[0107] Different from Example 1, the first alumina powder (particle size D 50 10 μm) 61.25 g, second alumina powder (particle size D 50 2 μm) 24.5 g, silicon dioxide (particle size D 50 That is, in this embodiment, the mass ratio of the first alumina powder, the second alumina powder and the silicon dioxide is 2.5:1:0.01.

[0108] Example 4

[0109] Different from Example 1, the first alumina powder (particle size D 50 10 μm) 41.95 g, the second alumina powder (particle size D 50 2μm) 41.95g, silicon dioxide (particle size D 50 That is, in this embodiment, the mass ratio of the first alumina powder, the second alumina powder and the silicon dioxide is 1:1:0.05.

[0110] Example 5

[0111] Different from Example 1, the first alumina powder (particle size D 50 10 μm) 60.56 g, the second alumina powder (particle size D 50 2 μm) 24.23 g, silicon dioxide (particle size D 50 That is, in this embodiment, the mass ratio of the first alumina powder, the second alumina powder and the silicon dioxide is 2.5:1:0.05.

[0112] Example 6

[0113] Different from Example 1, the insulating thermal conductive material of this embodiment contains 9.03 g of bisphenol F diglycidyl ether, 2.58 g of 1,6-hexanediol diglycidyl ether, 1.29 g of polypropylene glycol diglycidyl ether, and 0.9 g of 1-cyanoethyl-2-ethyl-4-methylimidazole. That is, in this embodiment, the mass ratio of the active diluent, the epoxy monomer, and the curing agent is 0.429:1:0.1.

[0114] Example 7

[0115] Different from Example 1, the insulating thermally conductive material of this embodiment includes the following components:

[0116] The first alumina powder (particle size D 50 10 μm) 60 g, the second alumina powder (particle size D 50 The remaining components are the same as those in Example 1.

[0117] Example 8

[0118] Different from Example 1, in the method for preparing the insulating thermally conductive material of this embodiment, the mixing and stirring speed of step (2) is 500 rpm, the time is 200 s, and no segmented stirring is performed.

[0119] Comparative Example 1

[0120] Different from Example 1, the insulating thermally conductive material of this comparative example includes the following components by mass:

[0121] The first alumina powder (particle size D 50 10 μm) 51.24 g, the second alumina powder (particle size D 50 2μm) 34.16g, silicon dioxide (particle size D 50 12nm) 0.6g, bisphenol F diglycidyl ether 7.67g, 1,6-hexanediol diglycidyl ether 3.58g, polypropylene glycol diglycidyl ether 1.79g, 1-cyanoethyl-2-ethyl-4-methylimidazole 0.77g, defoamer BYK-A530 0.2g. That is, in this embodiment, the mass ratio of the first alumina powder, the second alumina powder and silicon dioxide is 1.5:1:0.018, and the mass ratio of the active diluent, the epoxy monomer and the curing agent is 0.7:1:0.1.

[0122] Comparative Example 2

[0123] Different from Example 1, the insulating thermally conductive material of this comparative example includes the following components by mass:

[0124] The first alumina powder (particle size D 50 10 μm) 51.24 g, the second alumina powder (particle size D 50 2μm) 34.16g, silicon dioxide (particle size D 50 12nm) 0.6g, bisphenol F diglycidyl ether 10.88g, 1,6-hexanediol diglycidyl ether 1.87g, polypropylene glycol diglycidyl ether 0.93g, 1-cyanoethyl-2-ethyl-4-methylimidazole 0.12g, defoamer BYK-A530 0.2g. That is, in this embodiment, the mass ratio of the first alumina powder, the second alumina powder and silicon dioxide is 1.5:1:0.018, and the mass ratio of the active diluent, the epoxy monomer and the curing agent is 0.257:1:0.011.

[0125] The viscosity, thermal conductivity and insulation performance of the insulating thermally conductive materials in Examples 1-8 and Comparative Examples 1-2 were measured.

[0126] The viscosity is determined according to the method of "GB / T 2794-2022 Determination of viscosity of adhesives".

[0127] Thermal conductivity is determined according to ISO 22007-2:2022 Plastics. Determination of thermal conductivity and thermal diffusivity. Part 2: Transient plane heat source (hot plate) method.

[0128] The insulation performance is determined in accordance with "GB / T 31838.5-2021 Dielectric and resistive properties of solid insulating materials Part 5: Resistance characteristics (DC method) Volume resistance and volume resistivity of impregnated and coated materials".

[0129] The test results are shown in Table 1.

[0130] Table 1 Performance test table of insulating thermal conductive materials in Examples 1-8 and Comparative Examples 1-2

[0131]

[0132]

[0133] It can be seen from Table 1 that the materials in the embodiments of the present invention meet the requirements of insulation and thermal conductivity. By comparing the embodiments and comparative examples, it can be seen that the viscosity stability of the insulating thermally conductive materials in the embodiments of the present invention is significantly improved.

[0134] By comparing Example 1 with Comparative Example 1, it can be seen that when the amount of active diluent added exceeds the amount specified in the present invention, the viscosity increase of the material after 24 hours increases from 1% to 46.7%, indicating that the viscosity stability of the insulating thermal conductive material is significantly deteriorated. In addition, when the amount of active diluent added exceeds the amount specified in the present invention, the coating formed by the material changes from insulating to conductive, and cannot meet the insulation requirements.

[0135] By comparing Example 1 with Comparative Example 2, it can be seen that when the amount of curing agent added is lower than the amount specified in the present invention, the viscosity increase of the material after 24 hours increases from 1% to 59.3%, indicating that the viscosity stability of the insulating thermal conductive material is significantly deteriorated. In addition, when the amount of curing agent added is lower than the amount specified in the present invention, the coating formed by the material also changes from insulating to conductive, and cannot meet the insulation requirements.

[0136] By comparing Example 1 with Example 7, it can be seen that the present invention can significantly improve the thermal conductivity and viscosity stability of the material by grading three powders with different particle sizes to form an insulating thermal filler. By comparing Example 1 with Example 8, it can be seen that the present invention can significantly improve the viscosity stability of the material by using a segmented stirring method to prepare an insulating thermal conductive material.

[0137] Example 9

[0138] A power component, reference Figure 3 As shown, it includes a power device 200 and a heat sink 100 . The power device 200 is arranged in contact with the insulating thermal conductive coating 102 , and the power device 200 is fixed to the heat sink body 101 of the heat sink 100 by a fastener 300 .

[0139] In this embodiment, the fastener 300 includes a pressure strip 301 and a screw 302. The pressure strip 301 is provided with a contact surface and a mounting surface. The contact surface of the pressure strip 301 abuts against the surface of the power device 200, and the mounting surface of the pressure strip 301 abuts against the surface of the radiator body 101. The screw 302 is penetrated through the mounting surface of the pressure strip 301 to be fixed to the radiator body 101.

[0140] Specifically, the pressure strip 301 is composed of a first flat plate portion, a second flat plate portion and a vertical connection portion. The first flat plate portion and the second flat plate portion are parallel and staggered in an up-and-down manner. The vertical connection portion is connected between the ends of the first flat plate portion and the second flat plate portion. Figure 2 For example, the first flat plate portion is located above and to the right of the second flat plate portion, and the vertical connection portion is connected between the left end of the first flat plate portion and the right end of the second flat plate portion. At this time, the lower surface of the first flat plate portion forms the contact surface of the pressure strip 301, and the lower surface of the second flat plate portion forms the installation surface of the pressure strip 301.

[0141] When installing the power assembly of this embodiment, the heat sink can be first installed into the tooling, and then the power components and the pressure strips are placed in sequence, and finally the components are tightened by screws.

[0142] It should be noted that, in practical applications, silicone grease may be printed / sprayed on the heat sink, or printed / sprayed on the power device, which may further improve the thermal conductivity efficiency.

[0143] Example 10

[0144] Different from the ninth embodiment, the power assembly of the present embodiment further comprises a PCB board 400, and the fastener 300 is a screw. Figure 4 As shown, the power device 200 is fixed on the PCB board 400 , and the power device 200 is located between the heat sink body 101 and the PCB board 400 , and screws are passed through the PCB board 400 to be fixed to the heat sink body 101 .

[0145] In order to further improve the thermal conductivity efficiency, in this embodiment, the insulating thermal conductive coating layer 102 is further covered with a thermal conductive gel layer 103 . At this time, the power device 200 is arranged in contact with the thermal conductive gel layer 103 .

[0146] When installing the power component of this embodiment, the power component can be first welded on the PCB board to form a PCBA, and then the heat sink can be installed into the tooling, and thermal conductive gel can be applied on the insulating thermal conductive coating of the heat sink, and then the power device can be placed and locked with screws.

[0147] Embodiment 11

[0148] Different from the embodiment 10, the power device 200 of this embodiment is arranged on the outside of the PCB board 400. Figure 5As shown, the PCB board 400 is arranged between the power device 200 and the radiator body 101. At this time, a plurality of heat conducting holes 401 are opened on the PCB board 400. The setting positions of the heat conducting holes 401 correspond to the power device 200 so as to transfer the heat generated by the power device 200 to the radiator body 101 through the heat conducting holes 401.

[0149] Example 12

[0150] Different from the embodiments 9-11, the power device 200 of this embodiment is bonded and fixed to the heat sink 100. Figure 6 As shown, the power device 200 is directly bonded to the insulating thermal conductive coating 102 .

[0151] The specific manufacturing process of the power component of this embodiment includes the following steps:

[0152] (1) A layer of insulating thermal conductive material is coated on the surface of the radiator body by screen printing or spraying. In order to obtain good electrical insulation and thermal conductivity, the coating thickness of the insulating thermal conductive material is controlled to be between 45-60 μm;

[0153] (2) placing the heat sink body in step (1) in a high-temperature curing furnace for curing at a temperature of 190° C. for a curing time of 20 min, and forming a layer of insulating thermal conductive coating after curing;

[0154] (3) printing or spraying an insulating thermally conductive material on the surface of the insulating thermally conductive coating formed in step (2), controlling the coverage thickness of the insulating thermally conductive material to be between 45 μm and 60 μm, and then placing the power device on the insulating thermally conductive material;

[0155] (4) The heat sink body in step (3) is placed in a high-temperature curing furnace for curing at a temperature of 165° C. for 60 minutes. After the curing is completed, the power device is bonded and fixed to the heat sink to form a power component.

[0156] The power component of this embodiment does not use fasteners such as pressure strip screws, which can save space and is suitable for scenarios with limited installation space.

[0157] Embodiment 13

[0158] Different from the embodiment 12, the power assembly of this embodiment further includes a PCB board 400. Figure 7 As shown, the PCB board 400 is bonded and fixed to the heat sink 100 , and the power device 200 is fixed on the PCB board 400 . A plurality of heat conduction holes 401 are provided on the PCB board 400 at positions corresponding to the positions of the power device 200 .

[0159] The specific manufacturing process of the power component of this embodiment includes the following steps:

[0160] (1) A layer of insulating thermal conductive material is coated on the surface of the PCB board by screen printing or spraying process, and the coating thickness of the insulating thermal conductive material is controlled to be between 45-60 μm, and then the PCB board is placed in a high-temperature curing furnace for curing at a temperature of 190° C. for a curing time of 20 minutes. After curing, a layer of insulating thermal conductive coating is formed on the surface of the PCB board;

[0161] (2) opening a thermal conductive hole on the PCB board obtained in step (1), and soldering a power device on the other surface of the PCB board (the surface not covered with the insulating thermal conductive coating) by SMT (surface mount technology) to form a PCBA;

[0162] (3) printing or spraying insulating thermal conductive material on the surface of the insulating thermal conductive coating of the PCBA in step (2), controlling the covering thickness of the insulating thermal conductive material to be between 45 and 60 μm, and then bonding the heat sink body to the insulating thermal conductive material;

[0163] (4) The finished product in step (3) is placed in a high-temperature curing furnace for curing at a temperature of 190° C. for 20 minutes. After the curing is completed, the power device is bonded and fixed to the heat sink to form a power component.

[0164] It should be noted that in other embodiments, the surface of the heat sink body may be first covered with insulating thermal conductive material to form an insulating thermal conductive coating layer, and then covered with insulating thermal conductive material, and the PCBA may be bonded to the insulating thermal conductive material, and then cured to bond and fix the power device to the heat sink.

[0165] The above description is only an exemplary embodiment of the present invention, and does not limit the patent scope of the present invention. All equivalent structural changes made by using the contents of the present invention specification and drawings under the technical concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. An insulating thermally conductive material, characterized in that: The composition comprises the following components in parts by weight: 80-95 parts of insulating thermal conductive filler, 3-15 parts of epoxy monomer, 1-5 parts of active diluent, and 0.2-4 parts of curing agent.

2. The insulating thermally conductive material according to claim 1, characterized in that: The insulating thermal conductive filler is selected from at least one of aluminum oxide, aluminum hydroxide, aluminum nitride, boron nitride, silicon carbide, and silicon dioxide.

3. The insulating thermally conductive material according to claim 1 or 2, characterized in that: The insulating thermally conductive filler has a spherical shape and a particle size D 50 0.001μm~30μm.

4. The insulating thermally conductive material according to claim 3, characterized in that: The insulating thermal conductive filler is composed of a first powder, a second powder and a third powder; The particle size D of the first powder 50 5 μm to 30 μm; and / or the particle size D of the second powder 50 is 0.1 μm to 5 μm; and / or the particle size D of the third powder 50 It is 0.001μm~0.1μm.

5. The insulating thermally conductive material according to claim 4, characterized in that: The mass ratio of the first powder, the second powder and the third powder is (1-2.5):1:(0.01-0.5).

6. The insulating thermally conductive material according to claim 1, characterized in that: The epoxy monomer is selected from at least one of bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, phenyl diglycidyl ether, naphthyl diglycidyl ether and glycerol triglycidyl ether.

7. The insulating thermally conductive material according to claim 1, characterized in that: The active diluent is selected from at least one of monoglycerol ether, diglycerol ether and triglycerol ether.

8. The insulating thermally conductive material according to claim 1 or 7, characterized in that: The active diluent is selected from at least one of butyl glycidyl ether, butanediol diglycidyl ether, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether and glycerol triglycidyl ether.

9. The insulating thermally conductive material according to claim 1, characterized in that: The curing agent is selected from at least one of anhydride curing agents, amine curing agents, and imidazole curing agents.

10. The insulating thermally conductive material according to claim 1 or 9, characterized in that: The curing agent is selected from at least one of methylhexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylnadic anhydride, polyetheramine D230, dicyandiamide, 2-heptadecylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 1-benzyl-2-methylimidazole, 1-benzyl-2-ethylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, and 1-cyanoethyl-2-undecylimidazole.

11. The insulating thermally conductive material according to claim 1, characterized in that: The insulating thermally conductive material further comprises 0.01 to 0.5 parts by weight of a defoaming agent.

12. A method for preparing an insulating thermally conductive material, characterized in that: The following steps are involved: Mix 3 to 15 parts by weight of epoxy monomer, 1 to 5 parts by weight of active diluent, and 0.2 to 4 parts by weight of curing agent, and dissolve and stir to obtain a mixed solution; 80 to 95 parts by weight of insulating thermal conductive filler are added into the mixed solution and mixed and stirred.

13. The method for preparing the insulating thermally conductive material according to claim 12, characterized in that: The parameters of the dissolving and stirring are: a rotation speed of 1000 rpm to 3000 rpm and a time of 1 min to 8 min; And / or, the mixing and stirring parameters are: rotation speed 100 rpm to 1500 rpm, time 0.4 min to 12 min.

14. The method for preparing the insulating thermally conductive material according to claim 13, characterized in that: The mixing and stirring is divided into four stages. The rotation speed of the first stage is 100rpm~700rpm, and the time is 0.1min-3min; the rotation speed of the second stage is 700rpm~1300rpm, and the time is 0.1min~3min; the rotation speed of the third stage is 1300rpm~2500rpm, and the time is 0.1min~3min; the rotation speed of the fourth stage is 700~1500rpm, and the time is 0.1min~3min.

15. The method for preparing the insulating thermally conductive material according to claim 12, characterized in that: The preparation method further comprises a degassing and stirring step, wherein the parameters of the degassing and stirring are: a rotation speed of 1000 rpm to 3000 rpm, a time of 1 min to 8 min, and a vacuum degree of (-90 kPa) to (-100 kPa).

16. The method for preparing the insulating thermally conductive material according to claim 12, characterized in that: The preparation method further comprises adding 0.01 to 0.5 parts by weight of a defoamer before dissolving and stirring to obtain the mixed solution.

17. Use of the insulating thermally conductive material according to any one of claims 1 to 11 or the insulating thermally conductive material prepared by the preparation method according to any one of claims 12 to 16 in electronic products.

18. The use according to claim 17, characterized in that The insulating thermally conductive material is coated or screen-printed on at least a portion of the surface of the heat-generating element in the electronic product, and the insulating thermally conductive coating is formed after curing.

19. A radiator, characterized in that: It comprises a heat sink body and an insulating thermally conductive coating arranged on a surface of one side of the heat sink body, wherein the insulating thermally conductive coating is formed by the insulating thermally conductive material according to any one of claims 1 to 11 or the insulating thermally conductive material prepared by the preparation method according to any one of claims 12 to 16.

20. The heat sink according to claim 19, characterized in that The thickness of the insulating thermal conductive coating is 80 μm to 120 μm.

21. A power component, characterized in that: It comprises a power device and the heat sink according to claim 19 or 20, wherein the power device is arranged in contact with the insulating thermal conductive coating.

22. The power assembly according to claim 21, characterized in that The power device is fixed to the heat sink via a fastener, or the power device is bonded to the heat sink via an insulating thermal conductive coating.

Images