Ultrathin heat-conducting insulating sheet and preparation method thereof

Abstract

The invention belongs to the field of heat-conducting insulating materials, and particularly relates to an ultrathin heat-conducting insulating sheet and a preparation method thereof. The ultrathin heat-conducting insulating sheet provided by the invention is prepared from the following raw materials: vinyl silicone oil, hydrogen-containing silicone oil, heat-conducting filler, a treating agent, an inhibitor and a catalyst, wherein the mass ratio of the vinyl silicone oil to the hydrogen-containing silicone oil is (18-20): (1.2-1.4), and the heat-conducting filler comprises spherical aluminum oxide. The ultrathin heat-conducting insulating sheet prepared by the invention is relatively thin, can be applied to heat dissipation of electronic equipment with relatively high precision, and is relatively high in hardness, relatively low in thermal resistance and excellent in heat-conducting property.

Description

Technical Field

[0001] The invention belongs to the field of thermally conductive insulating materials, and specifically relates to an ultra-thin thermally conductive insulating sheet and a preparation method thereof. Background Art

[0002] With the rapid advancement of science and technology and the continuous improvement of productivity, consumers' demand for digital products is becoming increasingly refined and convenient. The mainstream digital products on the current market mainly rely on electricity as a power source, but electric drive will inevitably cause heat loss problems. It is well known that the internal components of digital products are extremely sensitive to heat energy. If the heat cannot be dissipated in time, it may cause the internal temperature of the device to be too high, thereby weakening the product performance and even causing spontaneous combustion, posing a serious safety hazard. Therefore, effectively removing the internal heat of the device is crucial to ensure the stable operation of digital products and reduce safety risks.

[0003] To address this problem, the current common solution is to select a suitable thermally conductive material as a conductive medium between the heat source and the heat sink of the digital product to effectively dissipate the heat generated by the electrical energy. However, the thermally conductive materials used in high-precision electronic equipment must have good electrical properties in addition to thermal conductivity. In particular, when the voltage on both sides of the insulator inside the electronic device increases, the electric field force on the insulator also increases, which may lead to ionization collision, and then break down the insulator, causing safety hazards. Therefore, it is particularly urgent to develop a thermally conductive material that can withstand high breakdown voltage.

[0004] As an important thermal conductive material, ultra-thin thermal conductive insulating sheet is widely used in the transfer interface between electronic equipment and heat sink or product housing. Its high reliability, insulation, low contact thermal resistance and high thermal conductivity make it widely used in communication equipment, computers, household appliances and other fields. In addition, a major feature of ultra-thin thermal conductive insulating sheet is its thin thickness, usually between 0.1-0.3mm. For example, patent document CN117107526A discloses an ultra-thin thermal conductive insulating sheet with a single-sided coating thickness of 100-200μm, but the thickness of the product is still relatively large, making it difficult to apply to high-precision equipment.

[0005] Therefore, developing a thermally conductive insulating material that has excellent thermal conductivity and electrical properties, can withstand high breakdown voltage, is thin in thickness, and has relatively low cost is an industry technical problem that urgently needs to be solved. Summary of the invention

[0006] In order to solve the above technical problems, the first aspect of the present invention provides an ultra-thin thermally conductive insulating sheet, the raw materials for preparing the ultra-thin thermally conductive insulating sheet include: vinyl silicone oil, hydrogen-containing silicone oil, thermally conductive filler, treatment agent, inhibitor, and catalyst.

[0007] As an implementable case, the raw materials for preparing the ultra-thin thermally conductive insulating sheet include, by weight, 15-20 parts of vinyl silicone oil, 1-3 parts of hydrogenated silicone oil, 180-200 parts of thermally conductive filler, 0.3-0.5 parts of treating agent, 0.01-0.05 parts of inhibitor, and 0.05-0.2 parts of catalyst.

[0008] As an implementable example, the viscosity of the vinyl silicone oil at 25° C. is 1000-100000 mPa·S.

[0009] Furthermore, the viscosity of the vinyl silicone oil at 25° C. is 1000-10000 mPa·S.

[0010] As an implementable case, the vinyl content in the vinyl silicone oil is 0.01-6wt%.

[0011] Furthermore, the vinyl content of the vinyl silicone oil is 0.1-0.3 wt %.

[0012] Furthermore, the viscosity of the vinyl silicone oil at 25° C. is 2500 mPa·S, and the vinyl content is 0.23 wt %.

[0013] Furthermore, the brand of the vinyl silicone oil is VS2000L, purchased from Shanghai Jingri New Material Technology Co., Ltd.

[0014] Vinyl silicone oil can effectively transfer heat due to the special arrangement in its molecular structure; when it is added to ultra-thin thermally conductive insulating sheets as a raw material, it can significantly improve the thermal conductivity of the material, reduce thermal resistance, and heat can be transferred through the material more quickly and evenly, thereby effectively reducing the temperature of electronic products and improving their stability and service life. At the same time, the viscosity of vinyl silicone oil has a direct impact on its fluidity in ultra-thin thermally conductive insulating sheets; vinyl silicone oil with lower viscosity makes it easier to fill and solidify ultra-thin thermally conductive insulating sheets during processing, which not only improves production efficiency, but also ensures that the material can be evenly covered on the surface that needs heat dissipation; while vinyl silicone oil with higher viscosity has poor fluidity during processing and is difficult to distribute evenly, which will also affect the heat dissipation effect of ultra-thin thermally conductive insulating sheets; in addition, the viscosity of vinyl silicone oil not only affects its fluidity, but is also closely related to the mechanical properties of ultra-thin thermally conductive insulating sheets.

[0015] As the viscosity of vinyl silicone oil increases, the hardness and tensile strength of the ultra-thin thermally conductive insulating sheet will first increase and then decrease. This is mainly because the molecular chain of vinyl silicone oil with higher viscosity is longer and there are more cross-linking points on the molecular chain, thus forming a relatively complete cross-linking network structure during the curing process. However, when the viscosity is too high, the cross-linking points are too dense, which may cause the ultra-thin thermally conductive insulating sheet to easily produce stress concentration under stress, thereby affecting its mechanical properties. In addition to viscosity, the vinyl content of vinyl silicone oil also has an important influence on the mechanical properties of ultra-thin thermally conductive insulating sheets. The higher the vinyl content, the greater the cross-linking density of the ultra-thin thermally conductive insulating sheet is generally, and the higher the hardness is. However, too high a vinyl content may cause the ultra-thin thermally conductive insulating sheet to become brittle and its aging resistance to decrease. Therefore, when preparing an ultra-thin thermally conductive insulating sheet, it is necessary to select a suitable vinyl content to balance its hardness and toughness.

[0016] In the present invention, the preferred vinyl silicone oil at 25° C. has a viscosity of 1000-10000 mPa·S and a vinyl content of 0.1-0.3%, which can ensure that the ultra-thin thermally conductive insulating sheet has both low thermal resistance and high hardness, and can be better applied to electronic equipment to achieve the dual requirements of fast heat dissipation and high hardness.

[0017] As an implementable case, the hydrogen content of the hydrogen-containing silicone oil is 0.03-0.1%.

[0018] Furthermore, the content of the hydrogen-containing silicone oil is 0.07%.

[0019] Furthermore, the brand of the hydrogen-containing silicone oil is S304, which was purchased from Shanghai Jingri New Material Technology Co., Ltd.

[0020] Furthermore, the mass ratio of the vinyl silicone oil to the hydrogen-containing silicone oil is (18.1-20):(1.2-1.4).

[0021] Although hydrogen-containing silicone oil itself does not directly improve the thermal conductivity of the ultra-thin thermally conductive insulating sheet, it can indirectly affect the thermal conductivity by affecting the cross-linking density of the material and the arrangement of the molecular chain. Specifically, the addition of hydrogen-containing silicone oil can change the microstructure inside the ultra-thin thermally conductive insulating sheet, making the heat conduction path more optimized, thereby improving the thermal conductivity efficiency. In addition, the inventors found that the mass ratio of vinyl silicone oil and hydrogen-containing silicone oil can further improve the hardness and thermal conductivity of the product; the cross-linked network structure formed by the addition reaction of vinyl silicone oil and hydrogen-containing silicone oil makes the interior of the ultra-thin thermally conductive insulating sheet more compact and stable, reducing the gaps and defects inside the material, thereby reducing thermal resistance. However, hydrogen-containing silicone oil is not easy to be excessive. When the content of hydrogen-containing silicone oil is too high, the cross-linking points it provides will increase; too high cross-linking density may also cause the material to become too rigid, affecting its flexibility and processing performance; at the same time, too high a content of hydrogen-containing silicone oil may cause the heat conduction path inside the thermally conductive material to be blocked by too many cross-linking points, hindering the effective transfer of heat, thereby reducing thermal conductivity. Therefore, the preferred mass ratio of vinyl silicone oil to hydrogenated silicone oil in the present invention is (18.1-20): (1.2-1.4), which can achieve a dynamic balance between low thermal resistance and high hardness.

[0022] As an implementable case, the thermally conductive filler includes: one or more of spherical alumina, spherical boron nitride, spherical aluminum nitride, spherical zinc oxide, spherical magnesium oxide, spherical silicon carbide, spherical silicon nitride, and spherical quartz powder.

[0023] As an implementable case, the particle size of the thermally conductive filler is 0.1-3 μm, including one or more of 0.1 μm, 0.3 μm, 0.5 μm, 0.8 μm, 1 μm, 2 μm, and 3 μm.

[0024] Furthermore, the thermal conductive filler comprises spherical alumina with a particle size of 0.1-0.5 μm and spherical alumina with a particle size of 1-3 μm, and the mass ratio of the spherical alumina with a particle size of 0.1-0.5 μm to the spherical alumina with a particle size of 1-3 μm is (10-15): (3-5)

[0025] Furthermore, the thermal conductive filler includes spherical alumina with a particle size of 2 μm and spherical alumina with a particle size of 0.3 μm.

[0026] Furthermore, the mass ratio of the spherical alumina with a particle size of 2 μm to the spherical alumina with a particle size of 0.3 μm is 14:4.

[0027] The thermal conductive filler in the present invention is preferably spherical alumina. Spherical alumina particles have lower surface energy, are not easy to agglomerate between particles, can be more evenly dispersed in the matrix, and help to form a denser filling structure, thereby improving the hardness of the material; specifically, spherical alumina with a particle size of 2 μm has a relatively large particle size, so that it can form an effective thermal conductive channel in the ultra-thin thermal conductive insulating sheet; and spherical alumina with a particle size of 0.3 μm can be filled into the gaps between particles with a particle size of 2 μm, further improving the filling density; after compounding spherical alumina particles with a particle size of 2 μm and a particle size of 0.3 μm, a multi-scale thermal conductive network can be formed, with large particles serving as the main thermal conductive channel and small particles filling the gaps between the channels, forming a more compact and continuous thermal conductive path, and since the contact area between the particles is increased, the heat conduction efficiency is improved, the thermal resistance is lower, the thermal conductivity of the material is improved, and the product is given excellent insulation properties.

[0028] As an implementable case, the treatment agent includes: one or more of dodecyltrimethoxysilane, vinyltrimethoxysilane, trimethoxysilylpolydimethylsiloxane, octyltrimethoxysilane, n-octyltriethoxysilane, hydroxypolydimethylsiloxane, and glycol-based polydimethylsiloxane.

[0029] Furthermore, the treating agent is dodecyltrimethoxysilane.

[0030] Dodecyltrimethoxysilane can effectively disperse and compatibility in ultra-thin thermally conductive insulating sheets. Through chemical modification, dodecyltrimethoxysilane can treat spherical alumina, so that the thermally conductive filler is better dispersed in the polymer matrix and the interaction between the thermally conductive filler and the polymer matrix is ​​enhanced, which can further reduce the interfacial thermal resistance and improve the overall thermal conductivity of the ultra-thin thermally conductive insulating sheet.

[0031] As an implementable case, the catalyst includes: one of a platinum catalyst, a ruthenium-based catalyst, a rhodium-based catalyst, and a tin-based catalyst.

[0032] Furthermore, the catalyst is a platinum catalyst.

[0033] Platinum catalyst is a highly efficient catalyst for hydrosilylation reaction. In the system of vinyl silicone oil and hydrogen-containing silicone oil, platinum catalyst can significantly reduce the activation energy of the reaction, so that the vinyl in vinyl silicone oil and the hydrogen atoms in hydrogen-containing silicone oil can undergo addition reaction under mild conditions, promote the curing of the material, and form a more compact and uniform structure during the curing process, making the heat conduction between the thermally conductive fillers more efficient, thereby improving the thermal conductivity of the entire thermally conductive material. At the same time, platinum catalyst can also reduce the interfacial thermal resistance, making the heat transfer in the thermally conductive material smoother.

[0034] As an implementable example, the inhibitor includes: one or more of acetylenic alcohol compounds, polyvinyl polysiloxane, amide compounds, and maleate compounds.

[0035] Furthermore, the inhibitor is an alkynol compound, and the alkynol compound is: 1-ethynyl-1-cyclohexanol.

[0036] The acetylene group in 1-ethynyl-1-cyclohexanol has a high electrophilicity and can strongly coordinate with the active sites on the surface of the platinum catalyst, thereby blocking some of the active sites and reducing the catalyst's adsorption capacity for reactants; by inhibiting the activity of the platinum catalyst, 1-ethynyl-1-cyclohexanol can affect the curing process and cross-linking density of the ultra-thin thermal conductive insulating sheet, thereby increasing the hardness of the material and reducing thermal resistance.

[0037] A second aspect of the present invention provides an ultra-thin thermally conductive insulating sheet, comprising:

[0038] S1. Mix vinyl silicone oil, hydrogen silicone oil, thermal conductive filler, inhibitor and treatment agent evenly;

[0039] S2. Add a catalyst and mix evenly, then dilute, apply on a substrate, and heat cure to obtain the product.

[0040] As an implementable case, the substrate includes PI film and / or glass fiber film.

[0041] Beneficial Effects

[0042] (i) The present invention preferably uses vinyl silicone oil with a viscosity of 1000-10000 mPa·S at 25° C. and a vinyl content of 0.1-0.3%, which can ensure that the ultra-thin thermally conductive insulating sheet has both low thermal resistance and high hardness performance.

[0043] (ii) The raw materials prepared in the present invention include vinyl silicone oil and hydrogen-containing silicone oil, and the preferred mass ratio of vinyl silicone oil to hydrogen-containing silicone oil is (18.1-20): (1.2-1.4), which can enable the product to achieve a balance between low thermal resistance and high hardness.

[0044] (III) The thermally conductive filler in the present invention is preferably spherical alumina. Spherical alumina particles have lower surface energy and are not easy to agglomerate with each other, which is beneficial to improving the hardness of the ultra-thin thermally conductive insulating sheet.

[0045] (IV) The present invention further limits the particle size of spherical alumina, which can improve the thermal conductivity of the ultra-thin thermally conductive insulating sheet and also give the product excellent insulation properties.

[0046] (V) The product prepared by the present invention is relatively thin and can be applied to electronic equipment with higher precision. At the same time, the ultra-thin thermally conductive insulating sheet has higher hardness, lower thermal resistance and excellent thermal conductivity.

[0047] (VI) Generally speaking, the higher the thickness of the material, the higher the corresponding thermal resistance; however, the thermal resistance of the ultra-thin thermally conductive insulating sheet prepared by the present invention decreases first and then increases as the thickness of the product increases, and the ultra-thin thermally conductive insulating sheet has a wider range of applications. This is mainly because the ultra-thin thermally conductive insulating sheet uses a substrate PI film during the preparation process. When the material is thinner, due to the rigidity of the PI film, the contact area of ​​the material is small and the contact thermal resistance is large. As the material gradually thickens, the contact area increases, the contact thermal resistance decreases, and the overall thermal resistance of the material decreases; when the thickness of the material continues to increase, the contact area remains almost unchanged, the contact thermal resistance remains unchanged, but the thermal resistance of the material is positively correlated with the thickness, so the higher the thickness, the higher the thermal resistance of the material; wherein the thermal resistance calculation formula is: θ=L / (λS), L is the thickness of the thermal conductive material, S is the contact area, and λ represents the thermal conductivity. DETAILED DESCRIPTION

[0048] Example 1

[0049] The first aspect of this example provides an ultra-thin thermally conductive insulating sheet, the raw materials for its preparation are, by weight, 18.19 parts of vinyl silicone oil, 1.3 parts of hydrogenated silicone oil, 180 parts of thermally conductive filler, 0.4 parts of treating agent, 0.01 parts of inhibitor, and 0.1 parts of catalyst.

[0050] The brand of the vinyl silicone oil is VS2000L, which is purchased from Shanghai Jingri New Material Technology Co., Ltd.

[0051] The grade of the hydrogen-containing silicone oil is S304, which is purchased from Shanghai Jingri New Material Technology Co., Ltd.

[0052] The diluent is Isopar C, purchased from ExxonMobil Chemical Company.

[0053] The treating agent is dodecyltrimethoxysilane.

[0054] The inhibitor is 1-ethynyl-1-cyclopentanol.

[0055] The catalyst is a platinum catalyst with a brand name of PT3000, purchased from Shanghai Jingri New Material Technology Co., Ltd.

[0056] The thermal conductive filler comprises, by weight, 140 parts of spherical alumina with a particle size of 2 μm and 40 parts of spherical alumina with a particle size of 0.3 μm.

[0057] The second aspect of this example provides an ultra-thin thermally conductive insulating sheet, comprising:

[0058] S1. Mix vinyl silicone oil, hydrogen silicone oil, thermal conductive filler, inhibitor and treatment agent evenly;

[0059] S2. Add the catalyst and mix evenly, then add 120 parts of diluent to dilute, and apply it on a 25μm thick PI film, heat cure it at 120°C for 30 minutes, and obtain ultra-thin thermal conductive insulating sheets with thicknesses of 40μm, 50μm, 80μm, and 100μm respectively.

[0060] The products of different thicknesses prepared in Example 1 were subjected to thermal resistance test, and the test method was referenced to: ASTM 5470; the experimental results are shown in Table 1.

[0061] Table 1

[0062]

[0063]

[0064] It can be seen from the experimental data in Table 1 that the thermal resistance of the ultra-thin thermally conductive insulating sheet prepared by the present invention first decreases and then increases as the thickness of the product increases.

[0065] Example 2

[0066] The first aspect of this example provides an ultra-thin thermally conductive insulating sheet, the raw materials for its preparation are, by weight, 18.58 parts of vinyl silicone oil, 1.25 parts of hydrogenated silicone oil, 180 parts of thermally conductive filler, 0.4 parts of treating agent, 0.01 parts of inhibitor, and 0.1 parts of catalyst.

[0067] The brand of the vinyl silicone oil is VS2000L, which is purchased from Shanghai Jingri New Material Technology Co., Ltd.

[0068] The grade of the hydrogen-containing silicone oil is S304, which is purchased from Shanghai Jingri New Material Technology Co., Ltd.

[0069] The diluent is Isopar C, purchased from ExxonMobil Chemical Company.

[0070] The treating agent is dodecyltrimethoxysilane.

[0071] The inhibitor is 1-ethynyl-1-cyclopentanol.

[0072] The catalyst is a platinum catalyst with a brand name of PT3000, purchased from Shanghai Jingri New Material Technology Co., Ltd.

[0073] The thermal conductive filler comprises, by weight, 140 parts of spherical alumina with a particle size of 2 μm and 40 parts of spherical alumina with a particle size of 0.3 μm.

[0074] The second aspect of this example provides an ultra-thin thermally conductive insulating sheet, comprising:

[0075] S1. Mix vinyl silicone oil, hydrogen silicone oil, thermal conductive filler, inhibitor and treatment agent evenly;

[0076] S2. Add the catalyst and mix evenly, then add 120 parts of diluent to dilute, and apply it on a 25 μm thick PI film, heat cure it at 120°C for 30 minutes, and obtain an ultra-thin thermal conductive insulating sheet with a thickness of 50 μm.

[0077] The product obtained in Example 2 was subjected to a thermal resistance test according to the test method as described in ASTM 5470. The thermal resistance of the product was found to be 1.42°C·cm 2 / W.

[0078] Comparative Example 1

[0079] The first aspect of this example provides an ultra-thin thermally conductive insulating sheet, the raw materials for its preparation are, by weight, 17.99 parts of vinyl silicone oil, 1.5 parts of hydrogenated silicone oil, 180 parts of thermally conductive filler, 0.4 parts of treating agent, 0.01 parts of inhibitor, and 0.1 parts of catalyst.

[0080] The brand of the vinyl silicone oil is VS2000L, which is purchased from Shanghai Jingri New Material Technology Co., Ltd.

[0081] The grade of the hydrogen-containing silicone oil is S304, which is purchased from Shanghai Jingri New Material Technology Co., Ltd.

[0082] The diluent is Isopar C, purchased from ExxonMobil Chemical Company.

[0083] The treating agent is dodecyltrimethoxysilane.

[0084] The inhibitor is 1-ethynyl-1-cyclopentanol.

[0085] The catalyst is a platinum catalyst with a brand name of PT3000, purchased from Shanghai Jingri New Material Technology Co., Ltd.

[0086] The thermal conductive filler comprises, by weight, 140 parts of spherical alumina with a particle size of 2 μm and 40 parts of spherical alumina with a particle size of 0.3 μm.

[0087] The second aspect of this example provides an ultra-thin thermally conductive insulating sheet, comprising:

[0088] S1. Mix vinyl silicone oil, hydrogen silicone oil, thermal conductive filler, inhibitor and treatment agent evenly;

[0089] S2. Add the catalyst and mix evenly, then add 120 parts of diluent to dilute, and apply it on a 25 μm thick PI film, heat cure it at 120°C for 30 minutes, and obtain an ultra-thin thermal conductive insulating sheet with a thickness of 50 μm.

[0090] The product prepared in this example was subjected to a thermal resistance test, and the test method was referenced to: ASTM 5470; the thermal resistance of the product was measured to be 1.59℃·cm 2 / W.

[0091] Comparative Example 2

[0092] The first aspect of this example provides an ultra-thin thermally conductive insulating sheet, the raw materials for its preparation are, by weight, 18.19 parts of vinyl silicone oil, 1.3 parts of hydrogenated silicone oil, 180 parts of thermally conductive filler, 0.4 parts of treating agent, 0.01 parts of inhibitor, and 0.1 parts of catalyst.

[0093] The thermal conductive filler is calculated by weight as follows: 100 parts of spherical alumina with a particle size of 5 μm, 52 parts of spherical alumina with a particle size of 0.8 μm and 28 parts of spherical alumina with a particle size of 0.3 μm.

[0094] The brand of the vinyl silicone oil is VS2000L, which is purchased from Shanghai Jingri New Material Technology Co., Ltd.

[0095] The grade of the hydrogen-containing silicone oil is S304, which is purchased from Shanghai Jingri New Material Technology Co., Ltd.

[0096] The diluent is Isopar C, purchased from ExxonMobil Chemical Company.

[0097] The treating agent is dodecyltrimethoxysilane.

[0098] The inhibitor is 1-ethynyl-1-cyclopentanol.

[0099] The catalyst is a platinum catalyst with a brand name of PT3000, purchased from Shanghai Jingri New Material Technology Co., Ltd.

[0100] The second aspect of this example provides an ultra-thin thermally conductive insulating sheet, comprising:

[0101] S1. Mix vinyl silicone oil, hydrogen silicone oil, thermal conductive filler, inhibitor and treatment agent evenly;

[0102] S2. Add the catalyst and mix evenly, then add 120 parts of diluent to dilute, and apply it on a 25μm thick PI film, heat cure it at 120°C for 30 minutes, and obtain ultra-thin thermal conductive insulating sheets with thicknesses of 50μm, 80μm, 110μm, and 150μm respectively.

[0103] The products of different thicknesses prepared in this example were subjected to thermal resistance tests, and the test method was referenced to: ASTM 5470; the experimental results are detailed in Table 2.

[0104] Table 2

[0105] Product thickness <![CDATA[Thermal resistance (°C·cm 2 / W)]]> 50μm 2.4 80μm 1.96 110μm 1.89 150μm 1.63 300μm 2.55 500μm 3.29

[0106] Combining the experimental results of Example 1 and Comparative Example 2, it can be seen that the thermal resistance first decreases and then increases with the thickness when the type and proportion of the thermal conductive filler are different, but the thickness at which the thermal resistance is lowest is different. The thermal resistance of the ultra-thin thermal conductive insulating sheet prepared by the present invention has the characteristics of thinner thickness and lower thermal resistance only when the thermal conductive filler is 140 parts of spherical alumina with a particle size of 2 μm and 40 parts of spherical alumina with a particle size of 0.3 μm.

[0107] Comparative Example 3

[0108] The first aspect of this example provides an ultra-thin thermally conductive insulating sheet, the raw materials for its preparation are, by weight, 18 parts of vinyl silicone oil, 1.2 parts of hydrogenated silicone oil, 180 parts of thermally conductive filler, 0.3 parts of treating agent, 0.01 parts of inhibitor, and 0.05 parts of catalyst.

[0109] The brand of the vinyl silicone oil is VS2000L, which is purchased from Shanghai Jingri New Material Technology Co., Ltd.

[0110] The grade of the hydrogen-containing silicone oil is S304, which is purchased from Shanghai Jingri New Material Technology Co., Ltd.

[0111] The diluent is Isopar C, purchased from ExxonMobil Chemical Company.

[0112] The treating agent is dodecyltrimethoxysilane.

[0113] The inhibitor is 1-ethynyl-1-cyclopentanol.

[0114] The catalyst is a platinum catalyst with a brand name of PT3000, purchased from Shanghai Jingri New Material Technology Co., Ltd.

[0115] The thermal conductive filler comprises, by weight, 140 parts of spherical alumina with a particle size of 2 μm and 40 parts of spherical alumina with a particle size of 0.3 μm.

[0116] The second aspect of this example provides an ultra-thin thermally conductive insulating sheet, comprising:

[0117] S1. Mix vinyl silicone oil, hydrogen silicone oil, thermal conductive filler, inhibitor and treatment agent evenly;

[0118] S2. Add the catalyst and mix evenly, then add 120 parts of diluent to dilute, and apply it on a 25 μm thick PI film, heat cure it at 120° C. for 30 minutes to obtain an ultra-thin thermal conductive insulating sheet with a thickness of 50 μm.

[0119] The product obtained in Example 4 was subjected to a thermal resistance test according to the test method as described in ASTM 5470. The thermal resistance of the product was found to be 1.59°C·cm 2 / W.

[0120] Comparative Example 4

[0121] The first aspect of this example provides an ultra-thin thermally conductive insulating sheet, the raw materials for its preparation are, by weight, 20 parts of vinyl silicone oil, 1.4 parts of hydrogenated silicone oil, 180 parts of thermally conductive filler, 0.5 parts of treating agent, 0.05 parts of inhibitor, and 0.2 parts of catalyst.

[0122] The brand of the vinyl silicone oil is VS2000L, which is purchased from Shanghai Jingri New Material Technology Co., Ltd.

[0123] The grade of the hydrogen-containing silicone oil is S304, which is purchased from Shanghai Jingri New Material Technology Co., Ltd.

[0124] The diluent is Isopar C, purchased from ExxonMobil Chemical Company.

[0125] The treating agent is dodecyltrimethoxysilane.

[0126] The inhibitor is 1-ethynyl-1-cyclopentanol.

[0127] The catalyst is a platinum catalyst with a brand name of PT3000, purchased from Shanghai Jingri New Material Technology Co., Ltd.

[0128] The thermal conductive filler is calculated by weight as follows: 100 parts of spherical alumina with a particle size of 5 μm, 52 parts of spherical alumina with a particle size of 0.8 μm and 28 parts of spherical alumina with a particle size of 0.3 μm.

[0129] The second aspect of this example provides an ultra-thin thermally conductive insulating sheet, comprising:

[0130] S1. Mix vinyl silicone oil, hydrogen silicone oil, thermal conductive filler, inhibitor and treatment agent evenly;

[0131] S2. Add the catalyst and mix evenly, then add 120 parts of diluent to dilute, and apply it on a 25 μm thick PI film, heat cure it at 120° C. for 30 minutes to obtain an ultra-thin thermal conductive insulating sheet with a thickness of 50 μm.

[0132] The product prepared in this example was subjected to a thermal resistance test, and the test method was referenced to: ASTM 5470; the thermal resistance of the product was measured to be 2.09℃·cm 2 / W.

[0133] Comparative Example 5

[0134] The first aspect of this example provides an ultra-thin thermally conductive insulating sheet, the raw materials for its preparation are, by weight, 18.4 parts of vinyl silicone oil, 1.4 parts of hydrogenated silicone oil, 180 parts of thermally conductive filler, 0.4 parts of treating agent, 0.01 parts of inhibitor, and 0.1 parts of catalyst.

[0135] The brand of the vinyl silicone oil is RH-Vi311D (viscosity of 500 mPa·S at 25° C. and vinyl content of 0.43 wt %), which is purchased from Ningbo Runhe High-tech Materials Technology Co., Ltd.

[0136] The grade of the hydrogen-containing silicone oil is S304, which is purchased from Shanghai Jingri New Material Technology Co., Ltd.

[0137] The diluent is Isopar C, purchased from ExxonMobil Chemical Company.

[0138] The treating agent is dodecyltrimethoxysilane.

[0139] The inhibitor is 1-ethynyl-1-cyclopentanol.

[0140] The catalyst is a platinum catalyst with a brand name of PT3000, purchased from Shanghai Jingri New Material Technology Co., Ltd.

[0141] The thermal conductive filler comprises, by weight, 140 parts of spherical alumina with a particle size of 2 μm and 40 parts of spherical alumina with a particle size of 0.3 μm.

[0142] The second aspect of this example provides an ultra-thin thermally conductive insulating sheet, comprising:

[0143] S1. Mix vinyl silicone oil, hydrogen silicone oil, thermal conductive filler, inhibitor and treatment agent evenly;

[0144] S2. Add the catalyst and mix evenly, then add 120 parts of diluent to dilute, and apply it on a 25 μm thick PI film, heat cure it at 120° C. for 30 minutes to obtain an ultra-thin thermal conductive insulating sheet with a thickness of 50 μm.

[0145] The product prepared in this example was subjected to a thermal resistance test, and the test method was referenced to: ASTM 5470; the thermal resistance of the product was measured to be 2.72℃·cm 2 / W.

[0146] The raw materials of each component prepared in this example were mixed and rolled into a 2 mm thick gasket for hardness testing.

[0147] Test method reference: ASTM D2240-15 (2021); the product hardness is shore 00 52 Comparative Example 6

[0148] The first aspect of this example provides an ultra-thin thermally conductive insulating sheet, the raw materials for its preparation are, by weight, 19.3 parts of vinyl silicone oil, 1.2 parts of hydrogenated silicone oil, 180 parts of thermally conductive filler, 0.4 parts of treating agent, 0.01 parts of inhibitor, and 0.1 parts of catalyst.

[0149] The brand of the vinyl silicone oil is RH-Vi302 (viscosity of 20000 mPa·S at 25° C., vinyl content of 0.1 wt %), purchased from Ningbo Runhe High-tech Materials Technology Co., Ltd.

[0150] The grade of the hydrogen-containing silicone oil is S304, which is purchased from Shanghai Jingri New Material Technology Co., Ltd.

[0151] The diluent is Isopar C, purchased from ExxonMobil Chemical Company.

[0152] The treating agent is dodecyltrimethoxysilane.

[0153] The inhibitor is 1-ethynyl-1-cyclopentanol.

[0154] The catalyst is a platinum catalyst with a brand name of PT3000, purchased from Shanghai Jingri New Material Technology Co., Ltd.

[0155] The thermal conductive filler comprises, by weight, 140 parts of spherical alumina with a particle size of 2 μm and 40 parts of spherical alumina with a particle size of 0.3 μm.

[0156] In this example, due to the excessive viscosity of the vinyl silicone oil, the raw materials cannot be mixed evenly and the final product cannot be obtained.

[0157] Hardness test:

[0158] The raw materials of each component prepared in Examples 1-2 and Comparative Examples 1-5 were mixed and rolled into 2 mm thick gaskets for hardness testing.

[0159] Test method reference: ASTM D2240-15(2021).

[0160] The test results are shown in Table 3.

[0161] Table 3

[0162]

[0163]

Claims

1. An ultra-thin thermally conductive insulating sheet, characterized in that: The raw materials for preparing the ultra-thin thermal conductive insulating sheet include, by weight, 15-20 parts of vinyl silicone oil, 1-3 parts of hydrogenated silicone oil, 180-200 parts of thermal conductive filler, 0.3-0.5 parts of treating agent, 0.01-0.05 parts of inhibitor, and 0.05-0.2 parts of catalyst.

2. The ultra-thin thermally conductive insulating sheet according to claim 1, characterized in that: The catalyst comprises one of a platinum catalyst, a ruthenium-based catalyst, a rhodium-based catalyst and a tin-based catalyst.

3. The ultra-thin thermally conductive insulating sheet according to claim 1, characterized in that: The mass ratio of the vinyl silicone oil to the hydrogen-containing silicone oil is (18.1-20):(1.2-1.4).

4. The ultra-thin thermally conductive insulating sheet according to claim 3, characterized in that: The viscosity of the vinyl silicone oil at 25° C. is 1000-100000 mPa·S.

5. The ultra-thin thermally conductive insulating sheet according to claim 3, characterized in that: The vinyl content of the vinyl silicone oil is 0.01-6wt%.

6. The ultra-thin thermally conductive insulating sheet according to claim 3, characterized in that: The hydrogen content of the hydrogen-containing silicone oil is 0.03-0.1%.

7. The ultra-thin thermally conductive insulating sheet according to any one of claims 1 to 6, characterized in that: The thermal conductive filler includes one or more of spherical aluminum oxide, spherical boron nitride, spherical aluminum nitride, spherical zinc oxide, spherical magnesium oxide, spherical silicon carbide, spherical silicon nitride, and spherical quartz powder.

8. The ultra-thin thermally conductive insulating sheet according to claim 7, characterized in that: The thermal conductive filler comprises spherical alumina, and the particle size of the spherical alumina is 0.1-3 μm.

9. The ultra-thin thermally conductive insulating sheet according to claim 8, characterized in that: The thermal conductive filler comprises spherical alumina with a particle size of 0.1-0.5 μm and spherical alumina with a particle size of 1-3 μm, and the mass ratio of the spherical alumina with a particle size of 0.1-0.5 μm to the spherical alumina with a particle size of 1-3 μm is (10-15): (3-5).

10. A method for preparing an ultra-thin thermally conductive insulating sheet according to any one of claims 1 to 9, characterized in that: include: S1. Mix vinyl silicone oil, hydrogen silicone oil, thermal conductive filler, inhibitor and treatment agent evenly; S2. Add a catalyst and mix evenly, then dilute, apply on a substrate, and heat cure to obtain the product.

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