Preparation method of heat-conducting gasket and heat-conducting gasket

Abstract

The invention discloses a preparation method of a heat-conducting gasket and the heat-conducting gasket, and the preparation method comprises the following steps: carrying out first stirring treatment on a heat-conducting filler, silicone oil and a coupling agent to obtain first mixed slurry; performing second stirring treatment on the first mixed slurry, a cross-linking agent, an inhibitor and a platinum catalyst in a vacuum environment to obtain second mixed slurry; coating the surface of the first release film with a coating of an organosilicon compound by using a coating machine, then coating the upper surface of the coating with a second mixed slurry, and then pasting a second release film on the upper surface of the second mixed slurry; a compression roller of the coating machine is used for tabletting and forming in the direction from the second release film to the first release film, and a semi-finished heat-conducting fin is obtained through baking; the semi-finished heat-conducting sheet comprises a heat-conducting layer formed by tabletting a second mixed slurry and an organic silicon protective layer formed by tabletting a coating, which are stacked in sequence; and tearing off the second release film to expose the surface of the semi-finished heat-conducting fin, and carrying out surface hardening treatment on the semi-finished heat-conducting fin to obtain the heat-conducting gasket.

Description

Technical Field

[0001] This invention relates to the field of thermal interface materials technology, and in particular to a method for preparing a thermally conductive pad and the thermally conductive pad obtained by the method. Background Technology

[0002] With the continuous increase in power density and integration of electronic devices, thermal management has become a key factor affecting device reliability, performance, and lifespan. Silicone thermal pads, as typical TIMs (Thermal Interface Materials), are widely used in chip packaging, power modules, energy storage systems, and other fields. Their core function is to fill the micron-level air gap between the heat-generating element and the heat sink, establishing an efficient heat conduction path.

[0003] However, traditional thermal pads still have some shortcomings in practical applications: 1. Most existing thermal pads have poor compressibility, making it difficult to fully fill interface gaps, leading to increased contact thermal resistance and affecting heat dissipation. Furthermore, the pads generally have resilience, which can damage components. 2. Excessive mechanical stress: Rigid thermally conductive materials may apply excessive stress to precision electronic components (such as chips, ceramic substrates, solder joints, etc.) during assembly or thermal cycling, causing structural damage or reliability issues. 3. Poor operability: Some high-compression pads suffer from severe powder shedding or powder / material shedding on the PCB board, reducing their actual operability.

[0004] Therefore, it is of great significance to develop a thermally conductive pad that combines high compression without rebound, low stress, and good operability.

[0005] The present invention solves at least one of the above problems. Summary of the Invention

[0006] The purpose of this invention is to solve at least one problem in the background art. The thermally conductive pad prepared by this invention achieves a balance between mechanical stress and different thermal conductivity coefficients. It has the characteristics of high compression without rebound and low stress for different thermal conductivity coefficients, and can effectively solve the problem of powder and material shedding during the use of thermally conductive pads.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] A first aspect of the present invention provides a method for preparing a thermally conductive pad, comprising the following:

[0009] The thermally conductive filler, silicone oil, and coupling agent are subjected to a first stirring treatment to obtain a first mixed slurry.

[0010] The first mixed slurry, crosslinking agent, inhibitor and platinum catalyst were subjected to a second stirring treatment under vacuum to obtain a second mixed slurry.

[0011] Using a coating machine, an organosilicon compound coating is first applied to the surface of the first release film, then the second mixed slurry is applied to the upper surface of the coating, and finally the second release film is attached to the upper surface of the second mixed slurry.

[0012] The sheet is formed by pressing it along the direction of the second release film toward the first release film using the pressure rollers of the coating machine, and then baked to obtain a semi-finished heat-conducting sheet.

[0013] The aforementioned semi-finished heat-conducting sheet includes a heat-conducting layer formed by pressing the aforementioned second mixed slurry and an organosilicon protective layer formed by pressing the aforementioned coating, which are stacked in sequence.

[0014] The second release film is peeled off to expose the surface of the semi-finished thermal conductive sheet. Then, the surface of the semi-finished thermal conductive sheet is subjected to surface hardening treatment to obtain a thermal pad.

[0015] The beneficial effects of this invention are as follows: Under the action of a platinum catalyst and an inhibitor, the crosslinking agent (usually hydrogen-containing silicone oil with Si-H bonds) undergoes a hydrosilylation reaction with the vinyl groups (C=C) in the silicone oil, forming stable Si-CC-Si bonds. This connects the linear silicone oil molecular chains into a three-dimensional elastic network. The cured elastomer network encapsulates and "locks" the thermally conductive filler particles within it, preventing filler sedimentation and migration, thus giving the thermally conductive pad good compressive stress. Furthermore, the coupling agent acts as a "molecular bridge" connecting the matrix and the thermally conductive filler, reducing the interfacial thermal resistance between the silicone oil and the thermally conductive filler, thereby giving the thermally conductive pad good heat dissipation capabilities. This thermally conductive pad exhibits good compressive stress and heat dissipation capabilities, achieving a balance between mechanical stress and different thermal conductivity coefficients. It possesses high compression without rebound and low stress characteristics for different thermal conductivity coefficients, and effectively solves the problem of powder and material shedding during the use of thermally conductive pads.

[0016] In some feasible embodiments, the aforementioned organosilicon compound includes one or more of organosilicon resins and organosilicon gels.

[0017] In some feasible embodiments, by weight, the thermally conductive filler is 100 to 600 parts, the silicone oil is 10 to 29 parts, the crosslinking agent is 0.1 to 1 part, the coupling agent is 0.6 to 3 parts, the inhibitor is 0.02 to 0.1 parts, and the platinum catalyst is 0.02 to 1 part.

[0018] It also includes at least one of the following:

[0019] The aforementioned thermally conductive filler includes at least one of alumina, zinc oxide, aluminum nitride, boron nitride, and diamond;

[0020] The aforementioned silicone oil includes at least one of vinyl silicone oil, dimethyl silicone oil, and phenyl silicone oil;

[0021] The coupling agent mentioned above is at least one of isopropyltris(dioctylpyrophosphoryloxy)titanate, γ-aminopropyltriethoxysilane (KH-550), vinyltrimethoxysilane, and octyltrimethoxysilane;

[0022] The above inhibitors are at least one of 3-methyl-1-butyn-3-ol and 3-methyl-1-pentyn-3-ol;

[0023] The crosslinking agent mentioned above is hydrogen-containing silicone oil.

[0024] In some feasible implementations, the viscosity of the aforementioned silicone oil is 100 to 20,000 cp.s.

[0025] In some feasible embodiments, the conditions for the first stirring treatment mentioned above include: a stirring temperature of 40°C to 180°C and a stirring time of 60 min to 300 min;

[0026] And / or, the conditions for the second stirring treatment mentioned above include: a stirring temperature of 40℃ to 180℃ and a stirring time of 60 min to 300 min;

[0027] In some feasible implementations, the baking temperature is 50°C to 200°C, and the baking time is 15 min to 60 min.

[0028] In some feasible embodiments, the surface hardening treatment is EB curing, the voltage of the EB curing is 0.15 MeV to 0.6 MeV, the irradiation dose of the EB curing is 10 KGy to 80 KGy, and the EB curing time is 1 min to 5 min.

[0029] In some feasible implementations, both the first release film and the second release film are silicon-based release films or fluorine-based release films.

[0030] In a second aspect, the present invention provides a thermally conductive pad prepared by the above-described preparation method. Attached Figure Description

[0031] Figure 1 This is a flowchart of the steps involved in preparing a thermally conductive pad according to the present invention. Detailed Implementation

[0032] The exemplary embodiments will now be described more fully. However, the exemplary embodiments can be implemented in many forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided to make the invention more comprehensive and complete, and to fully convey the concept of the exemplary embodiments to those skilled in the art.

[0033] A first aspect of the present invention provides a method for preparing a thermally conductive pad, such as... Figure 1 As shown, it includes the following steps S1-S5.

[0034] Step S1: The thermally conductive filler, silicone oil and coupling agent are subjected to a first stirring treatment to obtain a first mixed slurry.

[0035] Optionally, by weight, the thermally conductive filler is 100 to 600 parts, for example, 100, 150, 200, 250, 300, 350, 400, 450, 500, 550 or 600 parts; the silicone oil is 10 to 29 parts, for example, 10, 23, 25, 27 or 29 parts; and the coupling agent is 0.6 to 3 parts, for example, 0.6, 1, 1.5, 2, 2.5 or 3 parts.

[0036] Optionally, the thermally conductive filler includes at least one selected from alumina, zinc oxide, aluminum nitride, boron nitride, and diamond. The silicone oil includes at least one selected from vinyl silicone oil, dimethyl silicone oil, and phenyl silicone oil. The coupling agent is at least one selected from isopropyltris(dioctylpyrophosphate)titanate, γ-aminopropyltriethoxysilane (KH-550), vinyltrimethoxysilane, and octyltrimethoxysilane. Optionally, the viscosity of the silicone oil is 100 cp.s to 20000 cp.s; for example, it can be 100 cp.s, 1000 cp.s, 5000 cp.s, 10000 cp.s, 15000 cp.s, or 20000 cp.s.

[0037] For example, the conditions for the first stirring treatment include: a stirring temperature of 40°C to 180°C, such as 40°C, 60°C, 80°C, 100°C, 120°C, 140°C, 160°C, or 180°C; and a stirring time of 60 min to 300 min, such as 60 min, 100 min, 140 min, 180 min, 220 min, 260 min, or 300 min.

[0038] Step S2: The first mixed slurry, crosslinking agent, inhibitor and platinum catalyst are subjected to a second stirring treatment under vacuum to obtain a second mixed slurry.

[0039] The inhibitor is 0.02 to 0.1 parts, for example, 0.02, 0.04, 0.06, 0.08 or 0.1 parts; the platinum catalyst is 0.02 to 0.1 parts, for example, 0.02, 0.04, 0.06, 0.08 or 0.1 parts; the crosslinking agent is 0.1 to 1 part, for example, 0.1, 0.3, 0.5, 0.7, 0.9 or 1 part.

[0040] The inhibitor is 3-methyl-1-butyn-3-ol or 3-methyl-1-pentyn-3-ol. The crosslinking agent is hydrogen-containing silicone oil.

[0041] For example, the conditions for the second stirring treatment include: a stirring temperature of 40°C to 180°C, such as 40°C, 60°C, 80°C, 100°C, 120°C, 140°C, 160°C, or 180°C; and a stirring time of 60 min to 300 min, such as 60 min, 100 min, 140 min, 180 min, 220 min, 260 min, or 300 min.

[0042] Step S3: Using a coating machine, first apply an organosilicon compound coating to the surface of the first release film, then apply a second mixed slurry to the upper surface of the coating, and then attach the second release film to the upper surface of the second mixed slurry.

[0043] Optionally, the organosilicon compound includes one or more of organosilicon resins and organosilicon gels, such as Shin-Etsu organosilicon resin KR-271.

[0044] Step S4: Use the pressure roller of the coating machine to press the sheet along the direction of the second release film toward the first release film, and bake it to obtain a semi-finished heat-conducting sheet.

[0045] For example, the baking temperature is 50℃ to 200℃, such as 50℃, 100℃, 150℃ or 200℃; the baking time is 15min to 60min, such as 15min, 30min, 45min or 60min.

[0046] The semi-finished heat-conducting sheet includes a heat-conducting layer formed by pressing a second mixed slurry and an organosilicon protective layer (1mm to 2mm thick) formed by pressing a coating material, which are stacked in sequence.

[0047] Due to the addition crosslinking of silicone oil and crosslinking agent, a flexible three-dimensional elastic network is formed, which encapsulates the thermally conductive filler. By applying a coating of silicone compound, an organosilicon protective layer can be formed on the lower surface of the thermally conductive layer. The organosilicon protective layer can better wet and cover the lower surface of the thermally conductive layer, and the vinyl groups on its surface can also participate in the crosslinking reaction, becoming rigid reinforcing points in the network. The thermally conductive filler particles are locked in a dense network interwoven with "flexible chains" and "rigid points", and cannot easily move or fall off. Therefore, the problem of powder and material shedding from the thermally conductive pad can be well avoided.

[0048] It should be noted that powder shedding is essentially the shedding of thermally conductive filler particles from the thermally conductive pad (organosilicon polymer matrix), while "feather shedding" refers to large pieces of material falling off.

[0049] Step S5: Peel off the second release film to expose the surface of the semi-finished thermal conductive sheet (i.e., the upper surface of the thermal conductive layer). Then, perform surface hardening treatment on the surface of the semi-finished thermal conductive sheet to obtain the thermal conductive pad.

[0050] Optionally, the surface hardening treatment is EB (Electron Beam) curing, with the EB curing voltage being 0.15 Mev to 0.6 Mev, for example, 0.15 Mev, 0.2 Mev, 0.3 Mev, 0.4 Mev, 0.5 Mev, or 0.6 Mev; the EB curing irradiation dose being 10 KGy to 80 KGy, for example, 10 KGy, 20 KGy, 30 KGy, 40 KGy, 50 KGy, 60 KGy, 70 KGy, or 80 KGy; and the EB curing time being 1 min to 5 min, for example, 1 min, 1.5 min, 2 min, 2.5 min, or 3 min.

[0051] EB curing utilizes the penetrability and high reaction efficiency of high-energy electron beams to achieve uniform, ultra-high cross-linking density "bulk curing" of the thermally conductive layer from the surface to the interior at room temperature. This forms a dense composite network with extremely high cohesive strength, no internal defects, and strong bonding, which imprisons the thermally conductive filler particles within it, fundamentally eliminating the problem of powder or material loss caused by insufficient curing, structural defects, or internal stress.

[0052] Furthermore, both the first and second release films can be silicon-based release films or fluorine-based release films.

[0053] In this invention, under the action of a platinum catalyst and an inhibitor, a crosslinking agent (usually hydrogen-containing silicone oil with Si-H bonds) undergoes a hydrosilylation reaction with the vinyl groups (C=C) in the silicone oil to form stable Si-CC-Si bonds. This connects the linear silicone oil molecular chains into a three-dimensional elastic network. The cured elastomer network encapsulates and "locks" the thermally conductive filler particles within it, preventing filler sedimentation and migration, thus giving the thermally conductive pad good compressive stress. Furthermore, by using a coupling agent as a "molecular bridge" connecting the matrix and the thermally conductive filler, the interfacial thermal resistance between the silicone oil and the thermally conductive filler is reduced, giving the thermally conductive pad good heat dissipation capabilities.

[0054] In a second aspect, the present invention provides a thermally conductive pad, which is prepared by the above-described preparation method.

[0055] This thermal pad has good compressive stress and heat dissipation capabilities, and can achieve a balance with mechanical stress under different thermal conductivity coefficients. It has the characteristics of high compression without rebound and low stress for different thermal conductivity coefficients, and can effectively solve the problem of powder and material shedding during the use of thermal pads.

[0056] The technical solution of the present invention will be described in more detail below. However, it should be understood that the following embodiments are merely for explaining and illustrating the technical solution, and do not limit the scope of this application. Moreover, unless otherwise specified, the various raw materials, reaction equipment, detection equipment, and methods used in the following embodiments are all known in the art.

[0057] Example 1

[0058] A method for preparing a thermally conductive pad is provided, comprising the following steps S1-S5.

[0059] Step S1: 280 parts of thermally conductive filler, 20 parts of silicone oil and 2 parts of coupling agent are subjected to a first stirring treatment to obtain a first mixed slurry.

[0060] The thermally conductive filler is alumina; the silicone oil consists of 10 parts of vinyl silicone oil with a viscosity of 20,000 cp.s and 10 parts of phenyl silicone oil with a viscosity of 5,000 cp.s; the coupling agent is octyltrimethoxysilane.

[0061] The conditions for the first stirring treatment include a stirring temperature of 130°C and a stirring time of 180 min.

[0062] Step S2: The first mixed slurry, 0.12 parts of crosslinking agent, 0.05 parts of inhibitor and 0.05 parts of platinum catalyst are subjected to a second stirring treatment under vacuum to obtain a second mixed slurry.

[0063] The crosslinking agent is hydrogen-containing silicone oil; the inhibitor is 3-methyl-1-butyn-3-ol.

[0064] The conditions for the second stirring treatment include a stirring temperature of 130℃ and a stirring time of 120 minutes.

[0065] Step S3: Using a coating machine, first apply an organosilicon compound coating to the surface of the first release film, then apply a second mixed slurry to the upper surface of the coating, and then attach the second release film to the upper surface of the second mixed slurry.

[0066] The organosilicon compound is Shin-Etsu organosilicon resin KR-271; both the first and second release films are fluorinated release films.

[0067] Step S4: Use the pressure roller of the coating machine to press the sheet along the direction of the second release film toward the first release film, and bake it to obtain a semi-finished heat-conducting sheet.

[0068] The baking temperature is 170℃ and the baking time is 30 minutes. The semi-finished heat-conducting sheet includes a heat-conducting layer formed by pressing a second mixed slurry and an organosilicon protective layer (0.15mm thick) formed by pressing a coating material in sequence.

[0069] Step S5: Peel off the second release film to expose the surface of the semi-finished thermal conductive sheet (i.e., the upper surface of the thermal conductive layer). Then, perform surface hardening treatment on the surface of the semi-finished thermal conductive sheet to obtain the thermal conductive pad.

[0070] The surface hardening treatment was EB curing, with an EB curing voltage of 0.4 MeV, an EB curing irradiation dose of 40 KGy, and an EB curing time of 3 min.

[0071] Example 2

[0072] A method for preparing a thermally conductive pad is provided, comprising the following steps S1-S5.

[0073] Step S1: 550 parts of thermally conductive filler, 25 parts of silicone oil and 2.8 parts of coupling agent are subjected to a first stirring treatment to obtain a first mixed slurry.

[0074] The thermally conductive filler is alumina; the silicone oil includes 10 parts of vinyl silicone oil with a viscosity of 500 cp.s and 15 parts of phenyl silicone oil with a viscosity of 100 cp.s; the coupling agent is octyltrimethoxysilane.

[0075] The conditions for the first stirring treatment include a stirring temperature of 130°C and a stirring time of 180 min.

[0076] Step S2: The first mixed slurry, 1 part of crosslinking agent, 0.07 parts of inhibitor and 0.07 parts of platinum catalyst are subjected to a second stirring treatment under vacuum to obtain a second mixed slurry.

[0077] The crosslinking agent is hydrogen-containing silicone oil; the inhibitor is 3-methyl-1-butyn-3-ol.

[0078] The conditions for the second stirring treatment include a stirring temperature of 130℃ and a stirring time of 120 minutes.

[0079] Step S3: Using a coating machine, first apply an organosilicon compound coating to the surface of the first release film, then apply a second mixed slurry to the upper surface of the coating, and then attach the second release film to the upper surface of the second mixed slurry.

[0080] The organosilicon compound is Shin-Etsu organosilicon resin KR-271; both the first and second release films are fluorinated release films.

[0081] Step S4: Use the pressure roller of the coating machine to press the sheet along the direction of the second release film toward the first release film, and bake it to obtain a semi-finished heat-conducting sheet.

[0082] The baking temperature is 170℃ and the baking time is 30 minutes. The semi-finished heat-conducting sheet includes a heat-conducting layer formed by pressing a second mixed slurry and an organosilicon protective layer (0.2 mm thick) formed by pressing a coating.

[0083] Step S5: Peel off the second release film to expose the surface of the semi-finished thermal conductive sheet (i.e., the upper surface of the thermal conductive layer). Then, perform surface hardening treatment on the surface of the semi-finished thermal conductive sheet to obtain the thermal conductive pad.

[0084] The surface hardening treatment was EB curing, with an EB curing voltage of 0.6 MeV, an EB curing irradiation dose of 80 KGy, and an EB curing time of 5 min.

[0085] Example 3

[0086] A method for preparing a thermally conductive pad is provided, comprising the following steps S1-S5.

[0087] Step S1: 600 parts of thermally conductive filler, 29 parts of silicone oil and 3 parts of coupling agent are subjected to a first stirring treatment to obtain a first mixed slurry.

[0088] The thermally conductive filler consists of 480 parts alumina and 120 parts zinc oxide; the silicone oil is a vinyl silicone oil with a viscosity of 100 cp.s; and the coupling agent is octyltrimethoxysilane.

[0089] The conditions for the first stirring treatment include a stirring temperature of 130°C and a stirring time of 180 min.

[0090] Step S2: The first mixed slurry, 1 part crosslinking agent, 1 part inhibitor and 1 part platinum catalyst are subjected to a second stirring treatment under vacuum to obtain the second mixed slurry.

[0091] The crosslinking agent is hydrogen-containing silicone oil; the inhibitor is 3-methyl-1-butyn-3-ol.

[0092] The conditions for the second stirring treatment include a stirring temperature of 130℃ and a stirring time of 120 minutes.

[0093] Step S3: Using a coating machine, first apply an organosilicon compound coating to the surface of the first release film, then apply a second mixed slurry to the upper surface of the coating, and then attach the second release film to the upper surface of the second mixed slurry.

[0094] The organosilicon compound is Shin-Etsu organosilicon resin KR-271; both the first and second release films are fluorinated release films.

[0095] Step S4: Use the pressure roller of the coating machine to press the sheet along the direction of the second release film toward the first release film, and bake it to obtain a semi-finished heat-conducting sheet.

[0096] The baking temperature is 170℃ and the baking time is 30 minutes. The semi-finished heat-conducting sheet includes a heat-conducting layer formed by pressing a second mixed slurry and an organosilicon protective layer (0.2 mm thick) formed by pressing a coating.

[0097] Step S5: Peel off the second release film to expose the surface of the semi-finished thermal conductive sheet (i.e., the upper surface of the thermal conductive layer). Then, perform surface hardening treatment on the surface of the semi-finished thermal conductive sheet to obtain the thermal conductive pad.

[0098] The surface hardening treatment was EB curing, with an EB curing voltage of 0.6 MeV, an EB curing irradiation dose of 80 KGy, and an EB curing time of 5 min.

[0099] Example 4

[0100] A method for preparing a thermally conductive pad is provided, comprising the following steps S1-S5.

[0101] Step S1: Mix 100 parts of thermally conductive filler, 10 parts of silicone oil and 0.8 parts of coupling agent to obtain a first mixed slurry.

[0102] The thermally conductive filler consists of 70 parts alumina and 30 parts aluminum nitride; the silicone oil is a vinyl silicone oil with a viscosity of 100 cp.s; and the coupling agent is octyltrimethoxysilane.

[0103] The conditions for the first stirring treatment include a stirring temperature of 130°C and a stirring time of 180 min.

[0104] Step S2: The first mixed slurry, 0.1 parts of crosslinking agent, 0.02 parts of inhibitor and 0.02 parts of platinum catalyst are subjected to a second stirring treatment under vacuum to obtain a second mixed slurry.

[0105] The crosslinking agent is hydrogen-containing silicone oil; the inhibitor is 3-methyl-1-butyn-3-ol.

[0106] The conditions for the second stirring treatment include a stirring temperature of 130℃ and a stirring time of 120 minutes.

[0107] Step S3: Using a coating machine, first apply an organosilicon compound coating to the surface of the first release film, then apply a second mixed slurry to the upper surface of the coating, and then attach the second release film to the upper surface of the second mixed slurry.

[0108] The organosilicon compound is Shin-Etsu organosilicon resin KR-271; both the first and second release films are fluorinated release films.

[0109] Step S4: Use the pressure roller of the coating machine to press the sheet along the direction of the second release film toward the first release film, and bake it to obtain a semi-finished heat-conducting sheet.

[0110] The baking temperature is 170℃ and the baking time is 30 minutes. The semi-finished heat-conducting sheet includes a heat-conducting layer formed by pressing a second mixed slurry and an organosilicon protective layer (0.1 mm thick) formed by pressing a coating.

[0111] Step S5: Peel off the second release film to expose the surface of the semi-finished thermal conductive sheet (i.e., the upper surface of the thermal conductive layer). Then, perform surface hardening treatment on the surface of the semi-finished thermal conductive sheet to obtain the thermal conductive pad.

[0112] The surface hardening treatment was EB curing, with an EB curing voltage of 0.15 MeV, an EB curing irradiation dose of 10 KGy, and an EB curing time of 1 min.

[0113] Comparative Example 1

[0114] A method for preparing a thermally conductive pad is provided, comprising the following steps S1-S4.

[0115] Step S1: Mix 100 parts of thermally conductive filler, 10 parts of silicone oil and 0.8 parts of coupling agent to obtain a first mixed slurry.

[0116] The thermally conductive filler consists of 70 parts alumina and 30 parts aluminum nitride; the silicone oil is a vinyl silicone oil with a viscosity of 100 cp.s; and the coupling agent is octyltrimethoxysilane.

[0117] The conditions for the first stirring treatment include a stirring temperature of 130°C and a stirring time of 180 min.

[0118] Step S2: The first mixed slurry, 0.1 parts of crosslinking agent, 0.02 parts of inhibitor and 0.02 parts of platinum catalyst are subjected to a second stirring treatment under vacuum to obtain a second mixed slurry.

[0119] The crosslinking agent is hydrogen-containing silicone oil; the inhibitor is 3-methyl-1-butyn-3-ol.

[0120] The conditions for the second stirring treatment include a stirring temperature of 130℃ and a stirring time of 120 minutes.

[0121] Step S3: Apply the first release film and the second release film to the lower and upper surfaces of the second mixed slurry, respectively.

[0122] Both the first and second release films are made of fluorinated release film.

[0123] Step S4: Use the pressure roller of the coating machine to press the sheet along the direction of the second release film toward the first release film, and bake it to obtain a heat-conducting pad.

[0124] The baking temperature is 170℃ and the baking time is 30 minutes.

[0125] Comparative Example 2

[0126] A method for preparing a thermally conductive pad is provided, comprising the following steps S1-S4.

[0127] Step S1: 600 parts of thermally conductive filler, 29 parts of silicone oil and 3 parts of coupling agent are subjected to a first stirring treatment to obtain a first mixed slurry.

[0128] The thermally conductive filler consists of 480 parts alumina and 120 parts zinc oxide; the silicone oil is a vinyl silicone oil with a viscosity of 100 cp.s; and the coupling agent is octyltrimethoxysilane.

[0129] The conditions for the first stirring treatment include a stirring temperature of 130°C and a stirring time of 180 min.

[0130] Step S2: The first mixed slurry, 1 part crosslinking agent, 1 part inhibitor and 1 part platinum catalyst are subjected to a second stirring treatment under vacuum to obtain the second mixed slurry.

[0131] The crosslinking agent is hydrogen-containing silicone oil; the inhibitor is 3-methyl-1-butyn-3-ol.

[0132] The conditions for the second stirring treatment include a stirring temperature of 130℃ and a stirring time of 120 minutes.

[0133] Step S3: Apply the first release film and the second release film to the lower and upper surfaces of the second mixed slurry, respectively.

[0134] Both the first and second release films are made of fluorinated release film.

[0135] Step S4: Use the pressure roller of the coating machine to press the sheet along the direction of the second release film toward the first release film, and bake it to obtain a heat-conducting pad.

[0136] The baking temperature is 170℃ and the baking time is 30 minutes.

[0137] I. The thermally conductive pads prepared in Examples 1-4 and Comparative Examples 1-2 were subjected to the following performance tests:

[0138] 1. The thermal conductivity was tested in accordance with ISO 22007-2 "Plastics - Determination of thermal conductivity and thermal diffusivity - Part 2: Instantaneous planar heat source (heating plate) method".

[0139] 2. Use a universal testing machine to test the transient and steady-state stresses under 50% compression.

[0140] 3. Observe the surface of the thermal pad to see if it is shedding powder.

[0141] 4. First, attach the thermal pads to the same uneven area on the same PCB board, place them at 80℃ for 2 hours, and then remove the thermal pads to observe whether powder is falling off.

[0142] II. The test data are shown in Table 1.

[0143]

[0144] Analysis shows that, compared to Comparative Examples 1 and 2, the thermal pads of Examples 1-4 can have good compressive stress at different thermal conductivity coefficients, achieving a balance between mechanical stress and thermal conductivity coefficients. They have the characteristics of high compression without rebound and low stress for different thermal conductivity coefficients, and can effectively solve the problem of powder and material shedding during the use of thermal pads.

[0145] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the invention without departing from the principles and spirit of the invention, and all such changes should fall within the protection scope of the claims of the present invention.

Claims

1. A method of making a thermal pad, comprising: The application relates to a preparation method of a heat-conducting gasket. The heat-conducting filler, silicon oil and coupling agent are subjected to first stirring treatment to obtain a first mixed slurry; The first mixed slurry, crosslinking agent, inhibitor and platinum gold catalyst are subjected to second stirring treatment in a vacuum environment to obtain a second mixed slurry; An organic silicon compound is coated on the surface of the first release film by using a coating machine, and then the second mixed slurry is coated on the upper surface of the coating, and then the second release film is attached to the upper surface of the second mixed slurry; The second release film is removed to expose the surface of the semi-finished heat-conducting sheet, and then the surface of the semi-finished heat-conducting sheet is subjected to surface hardening treatment to obtain the heat-conducting gasket. The organic silicon compound comprises one or more of organic silicon resin, organic silicon silica gel. The heat-conducting filler is 100-600 parts by weight, the silicon oil is 10-29 parts by weight, the crosslinking agent is 0.1-1 part by weight, the coupling agent is 0.6-3 parts by weight, the inhibitor is 0.02-0.1 part by weight, and the platinum gold catalyst is 0.02-1 part by weight.

2. The production method according to claim 1, characterized by, The heat-conducting filler comprises at least one of aluminum oxide, zinc oxide, aluminum nitride, boron nitride and diamond.

3. The preparation method according to claim 1, characterized in that, The silicon oil comprises at least one of vinyl silicon oil, dimethyl silicon oil and phenyl silicon oil. The coupling agent is at least one of isopropyl tri (dioctyl pyrophosphoric acyloxy) titanate, gamma-aminopropyl triethoxysilane (KH-550), vinyl trimethoxysilane and octyl trimethoxysilane. The inhibitor is at least one of 3-methyl-1-butyn-3-ol and 3-methyl-1-pentyn-3-ol. The crosslinking agent is hydrogen-containing silicon oil. The viscosity of the silicon oil is 100-20000 cp.s. The first stirring treatment is performed at a stirring temperature of 40-180 DEG C for 60-300 min. The second stirring treatment is performed at a stirring temperature of 40-180 DEG C for 60-300 min.

4. The method for preparing the guide according to claim 1, characterized in that, The baking temperature is 50-200 DEG C, and the baking time is 15-60 min.

5. The preparation method according to claim 1, characterized in that, The surface hardening treatment is EB curing, the voltage of the EB curing is 0.15-0.6 Mev, the irradiation dose of the EB curing is 10-80 KGy, and the time of the EB curing is 1-5 min. The first release film and the second release film are silicon-based release films or fluorine release films.

6. The method of claim 1, wherein, The heat-conducting gasket is prepared by the preparation method in any one of claims 1-8.

7. The preparation method according to claim 1, characterized in that, ​ 8. The method of claim 1, wherein, ​ 9. A thermal pad, characterized by, ​

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