A thermally conductive potting compound, its preparation method and application method

Abstract

This invention relates to the field of potting compound technology, and more particularly to a thermally conductive potting compound, its preparation method, and its application method. The invention provides a thermally conductive potting compound comprising component A and component B; component A, by weight, comprises: 24-28 parts of thermally conductive base adhesive; 0.7-1.0 parts of vinyl silicone oil; 0.05-0.15 parts of platinum catalyst; and 0.04-0.12 parts of colorant; component B, by weight, comprises: 24-28 parts of thermally conductive base adhesive; 0-0.4 parts of vinyl silicone oil; 0.8-0.9 parts of hydrogen-containing silicone oil; and 0.005-0.015 parts of inhibitor; the inhibitor includes ethynylcyclohexanol and / or methylbutynol. The thermally conductive potting compound provided by this invention has ultra-high thermal conductivity, low volatility and low viscosity, excellent mechanical properties, excellent electrical insulation properties, and superior storage stability, exhibiting no clumping or agglomeration after 6 months of storage.

Description

Technical Field

[0001] This invention relates to the field of potting compound technology, and in particular to a thermally conductive potting compound, its preparation method and application method. Background Technology

[0002] High thermal conductivity potting compounds have low viscosity, good leveling properties, and high thermal conductivity. They can fill gaps, provide moisture and shock protection, and are reworkable. Moisture and shock protection are indicated by the potting compound's low hardness, good flexibility, and good adhesion after curing.

[0003] Currently, spontaneous combustion caused by thermal runaway of new energy vehicle battery packs occurs frequently. Furthermore, in the fields of high-power-density electronic components and chip protection, as well as wearable smart devices, mobile charging devices have increasingly higher requirements for heat dissipation. Thermal conductivity needs further improvement, while viscosity and leveling properties cannot deteriorate, and better control of low-molecular-weight volatility is required. This is to avoid threats to product insulation and safety due to low-flash-point, low-molecular-weight volatility during use, and to ensure good storage stability during use, without sedimentation or caking after 6 months of transportation and storage. Adding sedimentation agents can solve the sedimentation problem, but it also leads to a sharp increase in viscosity.

[0004] Patent CN112812740A discloses a two-component high thermal conductivity self-leveling potting compound, its preparation method, and its application. The disclosed compound has a thermal conductivity of 4 W / mK and is characterized by low viscosity, good self-leveling properties, excellent flame retardancy, and good electrical insulation. This two-component high thermal conductivity self-leveling potting compound consists of A and B components. The thermally conductive powder mainly consists of spherical alumina particles of different sizes. It is prepared by directly mixing a treatment agent with a base polymer before adding the thermally conductive powder. The drawback of this method is that the treatment agent must be added in excess. The treatment agent cannot cover the entire surface of the thermally conductive powder; much of the treatment agent is dispersed in the base polymer. Excessive treatment agent, after long-term storage, causes cross-linking and hydrolysis of active alkoxy groups, leading to decreased storage stability and viscosity stability.

[0005] Patent CN110055028A discloses a low-viscosity, high-thermal-conductivity potting compound. It utilizes a combination of near-spherical and spherical alumina particles of varying sizes, along with additives such as β-hydroxyethyl methacrylate, dibutyltin dilaurate, and diisononyl phthalate to improve the potting compound's leveling properties. The resulting low-viscosity, high-thermal-conductivity potting compound has a viscosity of 15000 cps and a thermal conductivity of 2.8 W / mK. However, its thermal conductivity still requires further improvement. Summary of the Invention

[0006] In view of this, the technical problem to be solved by the present invention is to provide a thermally conductive potting compound, its preparation method and application method, wherein the thermally conductive potting compound has ultra-high thermal conductivity, low volatility and low viscosity.

[0007] This invention provides a thermally conductive potting compound, comprising component A and component B;

[0008] Component A, by weight, comprises:

[0009]

[0010] Component B, by weight, comprises:

[0011]

[0012] The inhibitors include ethynylcyclohexanol and / or methylbutynol.

[0013] Preferably, the thermally conductive adhesive is obtained by mixing raw materials including vinyl silicone oil and treated powder;

[0014] The treated powder is prepared from raw materials including a treatment agent and a thermally conductive powder;

[0015] The treatment agent is prepared from raw materials comprising the following parts by weight:

[0016]

[0017] Preferably, the preparation method of the treatment agent includes the following steps:

[0018] Dodecyltrimethoxysilane, KH570, KH560 and acidic ion exchange resin are mixed and reacted under vacuum at 60-70°C for 0.4-0.6 h. After adding purified water dropwise, the reaction continues for 0.5-1.5 h. The mixture is then cooled to room temperature, and the acidic ion exchange resin is filtered off. The resulting filtrate is degraded at 75-85°C to obtain the treatment agent.

[0019] Preferably, the thermally conductive powder comprises, by weight, the following components:

[0020]

[0021] Preferably, the treated powder is prepared from raw materials including a treatment agent and a thermally conductive powder;

[0022] The method for preparing the treated powder includes the following steps:

[0023] The treatment agent is sprayed into the stirred thermally conductive powder. After stirring for 10 to 20 minutes, the temperature is raised to 90 to 110°C while stirring. Stirring is stopped and the temperature is maintained for 1 to 2 hours to obtain the treated powder.

[0024] The stirring rate of the thermally conductive powder is 500-1000 r / min.

[0025] Preferably, the method for preparing the thermally conductive adhesive includes the following steps:

[0026] Vinyl silicone oil and the treated powder are mixed evenly at a mass ratio of 0.5-1.5:23-27 to obtain a thermally conductive base adhesive.

[0027] Preferably, the viscosity of the vinyl silicone oil is 40–60 mPa·s;

[0028] The vinyl silicone oil is prepared from raw materials comprising the following parts by weight:

[0029]

[0030] The alkaline catalyst includes tetramethylammonium hydroxide alkaline gel.

[0031] Preferably, the method for preparing the vinyl silicone oil includes the following steps:

[0032] a) After mixing octamethylcyclotetrasiloxane and tetramethyltetravinylcyclotetrasiloxane, the mixture is dehydrated under vacuum at 60-70°C to obtain a dehydrated mixture;

[0033] b) The dehydrated mixture, tetramethyldivinyldisiloxane and alkaline catalyst are mixed and reacted under closed conditions at 100-120°C. Then, the mixture is dehydrated under vacuum at 170-190°C to obtain vinyl silicone oil.

[0034] Preferably, the mass ratio of component A to component B is 0.8 to 1.2:1;

[0035] The hydrogen content of the hydrogen-containing silicone oil is 0.05% to 0.8%.

[0036] This invention also provides a method for preparing the thermally conductive potting compound described above, comprising the following steps:

[0037] The thermally conductive adhesive, vinyl silicone oil, platinum catalyst and color paste in component A are mixed and stirred evenly under room temperature with cooling water. The mixture is then placed under vacuum and passed through a 50-200 mesh filter to obtain component A.

[0038] The thermally conductive base adhesive, vinyl silicone oil, and hydrogen-containing silicone oil in component B are mixed and stirred evenly under a cooling water circulatory environment at room temperature. Then, they are mixed with the inhibitor, placed under vacuum conditions, and filtered through a 50-200 mesh screen to obtain component B.

[0039] This invention also provides a method for using the thermally conductive potting compound described above, comprising the following steps:

[0040] Mix components A and B at a mass ratio of 0.8–1.2:1, degas under vacuum, fill and cure.

[0041] The thermally conductive potting compound is the thermally conductive potting compound described above, or the thermally conductive potting compound prepared by the preparation method described above.

[0042] This invention provides a thermally conductive potting compound, comprising component A and component B. Component A, by weight, comprises: 24-28 parts of thermally conductive base adhesive; 0.7-1.0 parts of vinyl silicone oil; 0.05-0.15 parts of platinum catalyst; and 0.04-0.12 parts of colorant. Component B, by weight, comprises: 24-28 parts of thermally conductive base adhesive; 0-0.4 parts of vinyl silicone oil; 0.8-0.9 parts of hydrogen-containing silicone oil; and 0.005-0.015 parts of inhibitor. The inhibitor comprises ethynylcyclohexanol and / or methylbutynol. The thermally conductive potting compound provided by this invention exhibits ultra-high thermal conductivity, low volatility and low viscosity, excellent mechanical properties, excellent electrical insulation properties, and superior storage stability, showing no agglomeration or clumping after 6 months of storage. Detailed Implementation

[0043] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0044] This invention provides a thermally conductive potting compound, comprising component A and component B;

[0045] Component A, by weight, comprises:

[0046]

[0047] Component B, by weight, comprises:

[0048]

[0049] The inhibitors include ethynylcyclohexanol and / or methylbutynol.

[0050] In some embodiments of the present invention, the thermally conductive adhesive is obtained by mixing raw materials including vinyl silicone oil and treated powder;

[0051] The processed powder is prepared from raw materials including a treatment agent and a thermally conductive powder.

[0052] In some embodiments of the present invention, the treatment agent is prepared from raw materials comprising the following parts by weight:

[0053]

[0054] In some embodiments of the present invention, the dodecyltrimethoxysilane is in the amount of 45 parts by weight.

[0055] In some embodiments of the present invention, the acidic ion exchange resin includes one of a strong acid cation exchange resin and a weak acid cation exchange resin. The strong acid cation exchange resin is mainly a macroporous strong acid cation exchange resin, specifically a cation exchange resin with sulfonic acid groups (-SO3H) on a macroporous styrene-divinylbenzene copolymer, more specifically D001 resin, POROS. TM XS resin or Lanxess SP112 resin. The weakly acidic cation exchange resin is mainly a cation exchange resin with carboxyl groups (-COOH groups) on a macroporous styrene-divinylbenzene copolymer, more specifically D113 resin or D061 resin. The above-mentioned acidic cation exchange resins are generally commercially available products. The acidic ion exchange resin is present in 5 parts by weight.

[0056] KH570 is γ-methacryloyloxypropyltrimethoxysilane, belonging to the siloxanes containing acryloyloxy groups. The weight fraction of KH570 is 30 parts.

[0057] KH560 is γ-(2,3-epoxypropoxy)propyltrimethoxysilane, belonging to the siloxanes containing epoxy groups. The weight fraction of KH560 is 15 parts.

[0058] The water is purified water. The weight percentage of the water is 5 parts.

[0059] In some embodiments of the present invention, the method for preparing the treatment agent includes the following steps:

[0060] Dodecyltrimethoxysilane, KH570, KH560 and acidic ion exchange resin are mixed and reacted under vacuum at 60-70℃ for 0.4-0.6 h. After adding purified water, the reaction continues for 0.5-1.5 h. The mixture is then cooled to room temperature, and the acidic ion exchange resin is filtered off. The resulting filtrate is degraded at 75-85℃ to obtain a slightly yellow transparent liquid, which is the treatment agent.

[0061] In some embodiments, the reaction is carried out under vacuum conditions at 65°C for 0.5 h.

[0062] In some embodiments, the rate at which the purified water is added is 1 to 2 drops per second.

[0063] In some embodiments, the reaction continues at a temperature of 60–70°C, specifically 65°C, and for a reaction time of 1 hour.

[0064] In some embodiments, the temperature for descaling is 80°C; the descaling time is 0.5 to 1.5 hours, specifically 1 hour.

[0065] In some embodiments of the present invention, the thermally conductive powder comprises, by weight, the following components:

[0066]

[0067] In some embodiments, the particle size of the 1-3 μm spherical alumina is 2 μm; the weight fraction is 10 parts.

[0068] In some embodiments, the particle size of the 5-10 μm spherical alumina is 10 μm; the weight fraction is 30 parts.

[0069] In some embodiments, the particle size of the 40-70 μm spherical alumina is 50 μm; the weight fraction is 50 parts.

[0070] In some embodiments, the 20-40 μm diamond powder has a particle size of 30 μm and a weight fraction of 10 parts.

[0071] The thermally conductive powder can be obtained by mixing 1-3 μm near-spherical alumina, 5-10 μm spherical alumina, 40-70 μm spherical alumina, and 20-40 μm diamond powder. The mixing is performed by stirring at a rate of 100-1000 r / min. The stirring is carried out in a high-speed mixer.

[0072] In some embodiments of the present invention, the treated powder is prepared from raw materials including a treatment agent and a thermally conductive powder.

[0073] In some embodiments of the present invention, the method for preparing the treated powder includes the following steps:

[0074] The treatment agent is sprayed into the stirred thermally conductive powder. After stirring for 10 to 20 minutes, the temperature is raised to 90 to 110°C while stirring. Stirring is stopped and the temperature is maintained for 1 to 2 hours to obtain the treated powder.

[0075] The stirring rate of the heat-conducting powder is 500-1000 r / min; specifically 800 r / min.

[0076] The treatment agent can be sprayed into the stirred thermally conductive powder using a spray device. Specifically, the spray device can be a vertical high-speed mixer.

[0077] In some embodiments, after stirring for 15 minutes, the temperature is raised to 100°C while stirring, stirring is stopped, and the temperature is maintained at 100°C for 1 hour.

[0078] The preparation of the processed powder is carried out in a high-speed mixer.

[0079] After the heat preservation is completed, the treatment agent can react completely with the active groups on the surface of the thermally conductive powder to obtain the treated powder.

[0080] In some embodiments of the present invention, the thermally conductive adhesive is obtained by mixing raw materials including vinyl silicone oil and treated powder.

[0081] In some embodiments of the present invention, the method for preparing the thermally conductive adhesive includes the following steps:

[0082] Vinyl silicone oil and the treated powder are mixed evenly at a mass ratio of 0.5-1.5:23-27 to obtain a thermally conductive base adhesive.

[0083] The mixing temperature is 0–40°C, specifically 25°C; the mixing time is 20–60 min, specifically 30 min.

[0084] The mixing is carried out in a kneader.

[0085] In some embodiments, the mass ratio of the vinyl silicone oil to the treated powder is 1:25.

[0086] In some embodiments of the present invention, the vinyl silicone oil has a volatile content of 0.01% to 0.10% by mass, specifically 0.05%; and a polar functional group content of 1 to 5 ppm by mass, specifically 3 ppm. The viscosity of the vinyl silicone oil is 40 to 60 mPa·s, specifically 50 mPa·s.

[0087] In some embodiments of the present invention, the vinyl silicone oil is prepared from raw materials comprising the following parts by weight:

[0088]

[0089] The alkaline catalyst includes tetramethylammonium hydroxide alkaline gel.

[0090] In some embodiments, the octamethylcyclotetrasiloxane has a purity of 99.8% and is manufactured by Wacker Chemie (Zhangjiagang) Co., Ltd.; the octamethylcyclotetrasiloxane is present in 80 or 90 parts by weight.

[0091] The vinyl double end cap has a purity of 99.5% and is manufactured by Zhejiang Quzhou Jiancheng Organosilicon Co., Ltd.; the vinyl double end cap has a weight of 18.5 parts or 25 parts.

[0092] The purity of tetramethyltetravinylcyclotetrasiloxane is 99.8%, and the manufacturer is Jiangxi Haiduo Organosilicon Materials Co., Ltd.; the weight parts of the tetramethyltetravinylcyclotetrasiloxane are 1 part or 4 parts.

[0093] The alkaline catalyst is 0.5 or 0.8 parts by weight.

[0094] In some embodiments of the present invention, the method for preparing the vinyl silicone oil includes the following steps:

[0095] a) After mixing octamethylcyclotetrasiloxane and tetramethyltetravinylcyclotetrasiloxane, the mixture is dehydrated under vacuum at 60-70°C to obtain a dehydrated mixture;

[0096] b) The dehydrated mixture, tetramethyldivinyldisiloxane and alkaline catalyst are mixed and reacted under closed conditions at 100-120°C. Then, the mixture is dehydrated under vacuum at 170-190°C to obtain vinyl silicone oil.

[0097] In step a):

[0098] In some embodiments of the present invention, the temperature for vacuum dehydration is 65°C; the time is 4 to 6 hours; specifically 5 hours.

[0099] In step b):

[0100] In some embodiments of the present invention, the reaction temperature is 110°C; the time is 3 to 4 hours; specifically 3 hours.

[0101] In some embodiments of the present invention, after the reaction, the temperature is further increased to 170-190°C; specifically, the temperature is increased to 180°C.

[0102] In some embodiments of the present invention, the vacuuming and de-lowering time is 2 to 3 hours; specifically 3 hours.

[0103] In some embodiments of the present invention, after vacuuming and depressurizing at 170–190°C, the process further includes: cooling to room temperature and then filtering.

[0104] In this invention, the vinyl silicone oil prepared according to the above method can be sealed and stored in an airtight container for later use. The vinyl silicone oil prepared by the above method has low impurity content, low volatile content, and a low content of side reactive functional groups such as hydroxyl groups. Reducing the content of polar functional groups in the vinyl silicone oil can effectively solve the compatibility problem between the silicone oil and the thermally conductive powder, thereby reducing viscosity and improving flowability.

[0105] In some embodiments of the present invention, the platinum catalyst includes at least one of the following: a caster platinum catalyst, a chloroplatinic acid isopropanol solution, a microencapsulated platinum catalyst (the platinum catalyst is coated with paraffin at 70°C), and a complex formed by chloroplatinic acid with ketones, cyclopentadiene, esters, alcohols, crown ethers, heteroatom-containing crown ethers, or polysiloxanes.

[0106] In some embodiments of the present invention, the color paste includes at least one of the following: a red color paste obtained by mixing iron oxide and silicone oil; a black color paste obtained by mixing iron oxide and silicone oil; a black color paste obtained by mixing nano-U carbon black and silicone oil; a blue color paste; and a white color paste obtained by mixing titanium dioxide and silicone oil; specifically, it can be U carbon black paste or iron black paste.

[0107] In some embodiments of the present invention, the hydrogen content (mass content) of the hydrogen-containing silicone oil is 0.05% to 0.8%, specifically 0.25%. The hydrogen-containing silicone oil is a methyl-terminated side-chain hydrogen-containing silicone oil (side-chain hydrogen-containing silicone oil, terminated by methyl groups). It is sourced from Jiangxi Haiduo Organosilicon Materials Co., Ltd., Zhejiang Runhe New Materials Co., Ltd., or Guangdong Chenxi New Materials Technology Co., Ltd.

[0108] In some embodiments of the present invention, component A comprises 26 parts by weight of thermally conductive adhesive; 0.7, 0.8, 0.9, or 1.0 parts by weight of vinyl silicone oil; 0.1 parts by weight of platinum catalyst; and 0.08 parts by weight of color paste.

[0109] In some embodiments of the present invention, component B comprises 26 parts by weight of thermally conductive adhesive; 0, 0.17, 0.27 or 0.37 parts by weight of vinyl silicone oil; 0.87 or 0.8 parts by weight of hydrogen-containing silicone oil; and 0.01 parts by weight of inhibitor.

[0110] In some embodiments of the present invention, the mass ratio of component A to component B is 0.8 to 1.2:1; specifically, it is 1:1.

[0111] In some embodiments of the present invention, the viscosity of component A is 15,000 to 35,000 mPa·s; specifically 28,500 mPa·s, 23,450 mPa·s, 20,980 mPa·s, 18,320 mPa·s or 21,100 mPa·s.

[0112] In some embodiments of the present invention, the viscosity of component B is 15,000 to 35,000 mPa·s; specifically 27,430 mPa·s, 21,670 mPa·s, 20,310 mPa·s, 17,678 mPa·s or 22,500 mPa·s.

[0113] This invention also provides a method for preparing the thermally conductive potting compound described above, comprising the following steps:

[0114] The thermally conductive adhesive, vinyl silicone oil, platinum catalyst and color paste in component A are mixed and stirred evenly under room temperature with cooling water. The mixture is then placed under vacuum and passed through a 50-200 mesh filter to obtain component A.

[0115] The thermally conductive base adhesive, vinyl silicone oil, and hydrogen-containing silicone oil in component B are mixed and stirred evenly under a cooling water circulatory environment at room temperature. Then, they are mixed with the inhibitor, placed under vacuum conditions, and filtered through a 50-200 mesh screen to obtain component B.

[0116] In some embodiments of the present invention, during the preparation of component A:

[0117] The mixing is carried out in a planetary reactor with a rotation speed of 100-1000 r / min (specifically 500 r / min) and a revolution speed of 10-50 Hz (specifically 25 Hz); and a mixing time of 10-60 min (specifically 30 min).

[0118] After the mixing process, the method further includes: vacuuming.

[0119] The vacuum level is -0.08 to -0.10 MPa, specifically -0.09 MPa; the vacuum time is 5 to 15 minutes, specifically 10 minutes.

[0120] In some embodiments of the present invention, during the preparation of component B:

[0121] The mixing is carried out in a planetary reactor with a rotation speed of 100-1000 r / min (specifically 500 r / min) and a revolution speed of 10-50 Hz (specifically 25 Hz). The mixing time is 10-60 min (specifically 30 min).

[0122] After the mixing process, the method further includes: vacuuming.

[0123] The vacuum level is -0.08 to -0.10 MPa, specifically -0.09 MPa; the vacuum time is 5 to 15 minutes, specifically 10 minutes.

[0124] This invention also provides a method for using a thermally conductive potting compound, comprising the following steps:

[0125] Mix components A and B at a mass ratio of 0.8–1.2:1, degas under vacuum, fill and cure.

[0126] The thermally conductive potting compound is the thermally conductive potting compound described above, or the thermally conductive potting compound prepared by the preparation method described above.

[0127] Specifically, the mass ratio of component A to component B is 1:1.

[0128] The curing method includes:

[0129] Curing time is 22–26 hours at room temperature, specifically 24 hours.

[0130] The curing temperature is 70–90°C, specifically 80°C; the curing time is 0.3–0.7 h, specifically 0.5 h.

[0131] Vinyl silicone oil has been mentioned in several places above. In some embodiments of the present invention, the same vinyl silicone oil may be used.

[0132] The present invention does not impose any special restrictions on the source of the raw materials used above, and they can be commercially available.

[0133] To further illustrate the present invention, the following describes in detail, in conjunction with embodiments, a thermally conductive potting compound, its preparation method, and its usage method, but these should not be construed as limiting the scope of protection of the present invention.

[0134] All reagents used in the following examples are commercially available.

[0135] In the embodiments, the purity of the octamethylcyclotetrasiloxane is 99.8%, and the manufacturer is Wacker Chemie (Zhangjiagang) Co., Ltd.; the purity of the vinyl double-ended head is 99.5%, and the manufacturer is Zhejiang Quzhou Jiancheng Organosilicon Co., Ltd.; the purity of the tetramethyltetravinylcyclotetrasiloxane is 99.8%, and the manufacturer is Jiangxi Haiduo Organosilicon Materials Co., Ltd.

[0136] Examples 1-4

[0137] 1) The treatment agent is prepared from raw materials comprising the following parts by weight:

[0138]

[0139] The acidic ion exchange resins are D001 resin (Example 1), D061 resin (Example 2), D113 resin (Example 3), and SP112 resin (Example 4).

[0140] The preparation method of the treatment agent includes the following steps:

[0141] Dodecyltrimethoxysilane, KH570, KH560 and acidic ion exchange resin were mixed and reacted at 65°C for 0.5 h under vacuum. After adding purified water (1-2 drops per second), the reaction was continued at 65°C for 1 h. The mixture was then cooled to room temperature, and the acidic ion exchange resin was filtered off. The filtrate was degraded at 80°C for 1 h to obtain a slightly yellow transparent liquid, which is the treatment agent.

[0142] 2) Thermal conductive powder includes, by weight, the following components:

[0143]

[0144] Preparation of thermal conductive powder:

[0145] The thermally conductive powder is obtained by mixing 1-3 μm spherical alumina, 5-10 μm spherical alumina, 40-70 μm spherical alumina and 20-40 μm diamond powder evenly in a high-speed mixer (stirring speed is 1000 r / min).

[0146] 3) The preparation method of the treated powder includes the following steps:

[0147] Add the thermally conductive powder to the high-speed mixer, turn on the high-speed mixer, and set the mixing speed of the high-speed mixer to 800 r / min. Spray the treatment agent into the powder in the high-speed mixer through a spray device (vertical high-speed mixer). After stirring for 15 minutes, heat the mixture to 100°C while stirring. Stop stirring and keep the mixture at 100°C for 1 hour to obtain the treated powder.

[0148] 4) Vinyl silicone oil is prepared from raw materials comprising the following parts by weight:

[0149]

[0150] The alkaline catalyst is tetramethylammonium hydroxide alkaline gel;

[0151] The method for preparing the vinyl silicone oil includes the following steps:

[0152] 4-1) In a 50L glass reactor, add octamethylcyclotetrasiloxane and tetramethyltetravinylcyclotetrasiloxane, and dehydrate under vacuum at 65°C for 5 hours to obtain a dehydrated mixture;

[0153] 4-2) After adding tetramethyldivinyldisiloxane and an alkaline catalyst to the dehydrated mixture, the mixture was reacted at 110°C for 3 hours under sealed conditions. Then, the temperature was raised to 180°C and vacuumed for 3 hours. After cooling to room temperature, the mixture was filtered to obtain vinyl silicone oil.

[0154] The vinyl silicone oil has a volatile content of 0.05% by mass, a polar functional group content of 3 ppm by mass, and a viscosity of 50 mPa·s.

[0155] 5) The preparation method of the thermally conductive adhesive includes the following steps:

[0156] The vinyl silicone oil and the treated powder were mixed uniformly in a kneader at 25°C for 30 minutes at a mass ratio of 1:25 to obtain a thermally conductive base adhesive.

[0157] 6) The thermally conductive potting compound consists of component A and component B;

[0158] Component A includes:

[0159] Thermally conductive adhesive, vinyl silicone oil, platinum catalyst (Castel platinum catalyst), and colorant (iron black colorant);

[0160] Preparation method of component A:

[0161] The vinyl silicone oil, thermally conductive adhesive, platinum catalyst, and colorant from component A were added to a planetary reactor in the specified proportions. The mixture was stirred thoroughly at room temperature with cooling water circulating through it. The stirring speed was 500 rpm (rotation speed) and 25 Hz (revolution speed) for 30 minutes. After stirring, a vacuum was applied and maintained at -0.09 MPa for 10 minutes. The mixture was then passed through a 150-mesh filter to obtain component A.

[0162] Component B includes:

[0163] Thermally conductive adhesive, vinyl silicone oil, hydrogen-containing silicone oil (methyl-terminated hydrogen silicone oil, Jiangxi Haiduo Organosilicon Materials Co., Ltd., with a hydrogen content of 0.25%) and inhibitors;

[0164] The inhibitor is ethynylcyclohexanol.

[0165] Preparation method of component B:

[0166] The thermally conductive base adhesive, vinyl silicone oil, and hydrogen-containing silicone oil in component B were mixed and stirred evenly under a cooling water supply at room temperature. The stirring speed was 500 r / min for rotation and 25 Hz for revolution. The stirring time was 30 min. Then, the mixture was mixed with the inhibitor and vacuumed. The vacuum degree was maintained at -0.09 MPa for 10 min. After vacuuming, the mixture was passed through a 150-mesh filter to obtain component B.

[0167] The application method of thermally conductive potting compound includes the following steps:

[0168] Mix components A and B at a mass ratio of 1:1, degas under vacuum, fill and cure at room temperature for 24 hours.

[0169] The properties of the prepared thermally conductive potting compound were tested, and the results are shown in Table 1. Specifically, volume resistivity was tested according to GB / T 40719, dielectric strength according to GB / T 1693, tensile strength according to GB / T 7124, viscosity according to GB / T 2794, and thermal conductivity according to ASTM D5470. The volatile matter was tested by placing 5g of sample in a glass evaporating dish, baking it in a 150℃ oven for 3 hours, and then weighing the mass loss rate.

[0170] Table 1. Components, weight parts, and performance test results of the thermally conductive potting compounds in Examples 1-4.

[0171]

[0172]

[0173] Comparative Examples 1-2

[0174] The difference from Example 1 lies in the different component contents of the treatment agent, as shown in Table 2.

[0175] Table 2. Components and weight parts of the treatment agents in Comparative Examples 1 and 2

[0176]

[0177]

[0178] Example 5 and Comparative Examples 3-4

[0179] The difference from Example 1 is that the component content of the vinyl silicone oil is different, as shown in Table 3.

[0180] Table 3. Components and weight parts of vinyl silicone oil in Example 5 and Comparative Examples 3-4

[0181]

[0182]

[0183] Comparative Example 5

[0184] The difference from Example 1 is as follows:

[0185] The vinyl silicone oil is a commercially available vinyl silicone oil with a viscosity of 50 mPa·s (Foshan Shunde Lanying Silicone Material Co., Ltd.), and the volatile matter content is 0.58% by mass.

[0186] The performance of the obtained thermally conductive potting compound was tested according to the above testing method, and the test results are shown in Table 4.

[0187] Table 4 shows the performance test results of the thermally conductive potting compound in Comparative Example 5.

[0188]

[0189] Comparative Example 6

[0190] The difference from Example 1 is as follows:

[0191] The treatment agent is n-octyltriethoxysilane.

[0192] Comparative Example 7

[0193] The difference from Example 1 is as follows:

[0194] The treatment agent is KH570.

[0195] The performance of the thermally conductive potting compounds obtained in Comparative Examples 6 and 7 was tested according to the above testing method. The test results are shown in Table 5.

[0196] Table 5 shows the performance test results of the thermally conductive potting compounds in Comparative Examples 6 and 7.

[0197]

[0198] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A thermally conductive potting compound, comprising component A and component B; Component A, by weight, comprises: 24-28 parts of thermally conductive adhesive; Vinyl silicone oil 0.7~1.0 parts; Platinum catalyst 0.05~0.15 parts; Color paste 0.04~0.12 parts; Component B, by weight, comprises: 24-28 parts of thermally conductive adhesive; Vinyl silicone oil 0~0.4 parts; Hydrogen-containing silicone oil: 0.8-0.9 parts; Inhibitor 0.005~0.015 parts; The thermally conductive adhesive is obtained by mixing raw materials including vinyl silicone oil and treated powder. The treated powder is prepared from raw materials including a treatment agent and a thermally conductive powder; The treatment agent is prepared from raw materials comprising the following parts by weight: 44-46 parts of dodecyltrimethoxysilane; KH570 20-30 servings; KH560 10~20 servings; 1-5 parts water; 4-6 parts of acidic ion exchange resin; The thermally conductive powder comprises, by weight, the following: 10-15 parts of 1-3 μm spherical alumina; 10-30 parts of 5-10 μm spherical alumina; 40-50 parts of spherical alumina with a diameter of 40-70 μm; 5-15 parts of 20-40 μm diamond powder; The viscosity of the vinyl silicone oil is 40~60 mPa·s; The vinyl silicone oil is prepared from raw materials comprising the following parts by weight: 60-95 parts of octamethylcyclotetrasiloxane; 10-30 parts of tetramethyldivinyldisiloxane; 0-5 parts of tetramethyltetravinylcyclotetrasiloxane; Alkali catalyst 0.5~1 part; The alkaline catalyst includes tetramethylammonium hydroxide alkaline gel; The inhibitors include ethynylcyclohexanol and / or methylbutynol.

2. The thermally conductive potting compound according to claim 1, characterized in that, The preparation method of the treatment agent includes the following steps: Dodecyltrimethoxysilane, KH570, KH560 and acidic ion exchange resin were mixed and reacted under vacuum at 60-70℃ for 0.4-0.6 h. After adding purified water dropwise, the reaction continued for 0.5-1.5 h. The mixture was then cooled to room temperature, and the acidic ion exchange resin was filtered off. The resulting filtrate was degraded at 75-85℃ to obtain the treatment agent.

3. The thermally conductive potting compound according to claim 1, characterized in that, The treated powder is prepared from raw materials including a treatment agent and a thermally conductive powder; The method for preparing the treated powder includes the following steps: The treatment agent is sprayed into the stirred thermally conductive powder. After stirring for 10-20 minutes, the temperature is raised to 90-110℃ while stirring. Stirring is stopped and the temperature is maintained for 1-2 hours to obtain the treated powder. The stirring rate of the thermally conductive powder is 500~1000 r / min.

4. The thermally conductive potting compound according to claim 1, characterized in that, The preparation method of the thermally conductive adhesive includes the following steps: Vinyl silicone oil and the treated powder are mixed evenly at a mass ratio of 0.5~1.5:23~27 to obtain thermally conductive base adhesive.

5. The thermally conductive potting compound according to claim 1, characterized in that, The method for preparing the vinyl silicone oil includes the following steps: a) After mixing octamethylcyclotetrasiloxane and tetramethyltetravinylcyclotetrasiloxane, the mixture is dehydrated under vacuum at 60~70°C to obtain a dehydrated mixture; b) The dehydrated mixture, tetramethyldivinyldisiloxane and alkaline catalyst are mixed and reacted under closed conditions at 100~120°C. Then, the mixture is dehydrated under vacuum at 170~190°C to obtain vinyl silicone oil.

6. The thermally conductive potting compound according to claim 1, characterized in that, The mass ratio of component A to component B is 0.8~1.2:1; The hydrogen content of the hydrogen-containing silicone oil is 0.05% to 0.8%.

7. A method for preparing the thermally conductive potting compound according to any one of claims 1 to 6, comprising the following steps: The thermally conductive adhesive, vinyl silicone oil, platinum catalyst and color paste in component A are mixed and stirred evenly under room temperature with cooling water. The mixture is then placed under vacuum and passed through a 50-200 mesh filter to obtain component A. The thermally conductive base adhesive, vinyl silicone oil, and hydrogen-containing silicone oil in component B are mixed and stirred evenly under a cooling water environment at room temperature. Then, they are mixed with the inhibitor, placed under vacuum conditions, and filtered through a 50-200 mesh screen to obtain component B.

8. A method for using a thermally conductive potting compound, comprising the following steps: Mix component A and component B at a mass ratio of 0.8~1.2:1, degas under vacuum, then fill and cure. The thermally conductive potting compound is the thermally conductive potting compound according to any one of claims 1 to 6, or the thermally conductive potting compound prepared by the preparation method according to claim 7.

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