Preparation method of a two-component high thermal conductivity silicone potting adhesive

Abstract

The present invention relates to the field of electronic heat-conducting potting adhesives, and discloses a preparation method of a two-component high heat-conducting silicone potting adhesive. The preparation raw materials include the following components in parts by weight: Component A includes 30-50 parts of hydroxyl-terminated polydimethylsiloxane, 100-300 parts of heat-conducting powder, 1-10 parts of dimethyl silicone oil, and 1-5 parts of pigment; Component B includes 5-30 parts of cross-linking agent, 1-30 parts of silane coupling agent, 20-100 parts of anti-settling silicone oil, 0.1-0.5 parts of catalyst, and the weight ratio of Component A to Component B is (1-10):1. The two-component high heat-conducting silicone potting adhesive provided by the present invention has the characteristics of low mixing ratio, large viscosity range of Component B, and no sedimentation during long-term storage, and is suitable for the requirements of high heat-conducting potting of high-power electronic devices.

Description

Technical Field

[0001] The present invention relates to the field of electronic heat-conducting potting adhesives, and particularly relates to a two-component high heat-conducting silicone potting adhesive and a preparation method thereof. Background Art

[0002] With the rapid development of industrial fields such as 5G communication, photovoltaic power generation, and new energy, the electronic components therein have gradually become more multifunctional and densified, which means that their power is gradually increasing and the heat generation is significantly increasing, posing higher and higher requirements for the thermal conductivity of potting adhesives. Currently, the thermal conductivity of common silicone potting adhesives on the market is generally 0.3 - 1.5 W / (m·k). The main way to increase the thermal conductivity of heat-conducting potting adhesives is to increase the filling amount of heat-conducting fillers through powder compounding, which will result in a relatively large density (>2 g / cm 3 ) and too high viscosity of component A. To ensure the curing effect, a common method is to increase the proportion of component A and component B used (10 - 20):1. The problem with this method is that the amount of component B discharged is small, and the equipment accuracy requirements are relatively high. A slight fluctuation in the ratio may cause problems such as abnormal curing of the potting adhesive, and the on-site debugging is difficult; another method is to add inert silicone oil to component B for volume filling to increase the amount of component B used to achieve the purpose of reducing the ratio of components used. However, the compatibility of common dimethyl silicone oil and polar coupling agents is limited, especially for high-viscosity silicone oil. A large amount of addition is likely to cause problems such as stratification and sedimentation after storage of component B, affecting the curing effect of the potting adhesive. And the viscosity of component B prepared with low-viscosity silicone oil is too different from that of component A. With the existing mainstream glue application equipment, the high-viscosity component A at the glue outlet is prone to generate internal pressure on the low-viscosity component B, resulting in the closing of the one-way valve of component B and unable to discharge glue normally; if the glue discharge pressure of component B is increased alone, it is easy to cause the gear pump to run idly and also unable to discharge glue normally.

[0003] Chinese Patent CN107760256A discloses a low-shrinkage heat-conducting and flame-retardant two-component condensation-type silicone potting adhesive, its preparation method and application. The mixing ratio of component A and component B is (5 - 10):1, and 100 - 500 cps dimethyl silicone oil is used as a plasticizer. This patent mentions that the cross-linking agent, coupling agent, catalyst, and plasticizer are mixed evenly in a reaction kettle and aged for 24 h, and the precipitate is filtered out to obtain component B. The content of the plasticizer is 48% - 69%. The component B prepared by this patent has a low viscosity and is not suitable for matching with a high heat-conducting component A (with a large viscosity), and the storage performance is not investigated.

[0004] Chinese Patent CN109897591A discloses a low-viscosity and high-thermal-conductivity potting adhesive and its preparation method. Spherical alumina is used to replace ordinary random alumina. Components A and B are mixed in a mass ratio of 1:1. The viscosities of components A and B are 2000 - 5800 cp, and the content of spherical alumina is 75% - 85%. After long-term storage, the powder is extremely prone to sedimentation, which affects the curing effect of the potting adhesive.

[0005] In summary, the cited patent documents do not provide satisfactory solutions to the problems that the glue ratio of the current high-thermal-conductivity silicone potting adhesive is difficult to adapt to the gluing equipment or the component B is prone to sedimentation. Summary of the Invention

[0006] The present invention aims to provide a two-component high-thermal-conductivity silicone potting adhesive and its preparation method to solve the problem in the prior art that component B is prone to sedimentation, resulting in poor matching between the potting adhesive and the glue application equipment.

[0007] To achieve the above object, the present invention adopts the following technical scheme: A two-component high-thermal-conductivity silicone potting adhesive includes component A and component B. Component A, by mass, includes the following raw materials: 30 - 50 parts of hydroxyl-terminated polydimethylsiloxane, 100 - 300 parts of thermal conductive powder, 1 - 10 parts of dimethyl silicone oil, and 1 - 5 parts of pigment; Component B, by mass, includes the following raw materials: 5 - 30 parts of crosslinking agent, 1 - 30 parts of silane coupling agent, 20 - 100 parts of anti-sedimentation silicone oil, and 0.1 - 0.5 parts of catalyst.

[0008] On the other hand, the present technical scheme provides a preparation method of a two-component high-thermal-conductivity silicone potting adhesive, including the following steps:

[0009] Step 1: Mix and stir hydroxyl-terminated polydimethylsiloxane, thermal conductive powder, and pigment to obtain a mixed material;

[0010] Step 2: After edging and stirring the mixed material obtained in Step 1 evenly, discharge it to obtain the high-thermal-conductivity potting adhesive component A;

[0011] Step 3: Stir crosslinking agent, silane coupling agent, anti-sedimentation silicone oil, and catalyst evenly to obtain the high-thermal-conductivity potting adhesive component B.

[0012] Preferably, as an improvement, the viscosity of the anti-sedimentation silicone oil at 25°C is 100 - 200000 mPa·s, and the structure of the anti-sedimentation silicone oil is as shown in formula (I):

[0013]

[0014] In formula (I), m is an integer between 0 and 500, n is an integer between 0 and 1500 (m and n are not both 0); R 1 is one of hydroxyl, methyl, vinyl, and phenyl; R2 It is obtained by hydrosilylation of alkoxy-containing hydrogen silicone oil and vinyl silicone oil.

[0015] Preferably, as an improvement, R 2 is one of several structures of formula (II) - formula (VI);

[0016]

[0017]

[0018] In formula (IV), x is an integer between 1 and 12.

[0019] Preferably, as an improvement, the viscosity of the hydroxyl-terminated polydimethylsiloxane is 500 - 20000 mPa·s, and the viscosity of the dimethyl silicone oil is 50 - 2000 mPa·s.

[0020] Preferably, as an improvement, the heat-conducting powder is alumina or aluminum hydroxide; the pigment is titanium white paste or carbon black paste; the cross-linking agent is a commercially available alkoxysilane cross-linking agent, specifically at least one of methyltrimethoxysilane, methyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, tetraethyl orthosilicate, polymethyltriethoxysilane, propyltrimethoxysilane, propyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, octyltrimethoxysilane.

[0021] Preferably, as an improvement, the silane coupling agent is at least one of γ-aminopropyltriethoxysilane, γ-aminoethylaminopropyltrimethoxysilane, N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane, N-(β-aminoethyl)-γ-aminopropyltriethoxysilane, γ-(2,3-epoxypropoxy)propyltrimethoxysilane.

[0022] Preferably, as an improvement, the catalyst is an organotin catalyst, and specifically one of dibutyltin dilaurate, dioctyltin dilaurate, and dibutyltin didecanoate can be selected.

[0023] Preferably, as an improvement, the stirring processes in Step 1 and Step 2 are both carried out under vacuum conditions.

[0024] Preferably, as an improvement, the mass ratio of component A to component B is (1 - 10):1.

[0025] Compared with the prior art, the present technical solution has the following technical advantages:

[0026] 1. The present technical solution uses self-made anti-settling silicone oil to volumetrically fill component B, and the mass ratio of component A to component B is (1 - 10):1, which reduces the precision requirements of the high thermal conductivity potting adhesive for equipment, and most commercially available glue applicators can be used at present.

[0027] 2. The silicone oil can effectively increase the viscosity of component B, reduce the viscosity difference between components A and B, and ensure the smooth dispensing of component B during glue application, thereby effectively ensuring the curing effect of the potting adhesive.

[0028] 3. The silicone oil, crosslinking agent, and coupling agent all have an alkoxysilane structure, resulting in significantly improved compatibility. The prepared component B has stable performance after long-term storage, without stratification or sedimentation. Detailed Embodiments

[0029] The following is a further detailed description through specific embodiments, but the embodiments of the present invention are not limited thereto. Unless otherwise specified, the technical means used in the following embodiments are conventional means well-known to those skilled in the art; the experimental methods used are all conventional methods; the materials, reagents, etc. used can all be obtained through commercial channels.

[0030] Overview of the Solution:

[0031] A two-component high thermal conductivity silicone potting adhesive includes component A and component B. Component A, in parts by mass, includes the following raw materials: 30 - 50 parts of hydroxyl-terminated polydimethylsiloxane, 100 - 300 parts of thermal conductive powder, 1 - 10 parts of dimethyl silicone oil, and 1 - 5 parts of pigment; Component B, in parts by mass, includes the following raw materials: 5 - 30 parts of crosslinking agent, 1 - 30 parts of silane coupling agent, 20 - 100 parts of anti-settling silicone oil, and 0.1 - 0.5 parts of catalyst.

[0032] The viscosity of the hydroxyl-terminated polydimethylsiloxane is 500 - 20000 mPa·s.

[0033] The thermal conductive powder is alumina or aluminum hydroxide.

[0034] The viscosity of the dimethyl silicone oil is 50 - 2000 mPa·s.

[0035] The pigment is titanium white paste or carbon black paste.

[0036] The crosslinking agent is a commercially available alkoxysilane crosslinking agent, specifically at least one of methyltrimethoxysilane, methyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, tetraethyl orthosilicate, polymethyltriethoxysilane, propyltrimethoxysilane, propyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, octyltrimethoxysilane.

[0037] The silane coupling agent is at least one of γ-aminopropyltriethoxysilane, γ-aminoethylaminopropyltrimethoxysilane, N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane, N-(β-aminoethyl)-γ-aminopropyltriethoxysilane, γ-(2,3-epoxypropoxy)propyltrimethoxysilane.

[0038] The viscosity of the anti-settling silicone oil at 25 °C is 100 - 200000 mPa·s, and its structure is shown in formula (I):

[0039]

[0040] In formula (I), m is an integer between 0 and 500, and n is an integer between 0 and 1500 (m and n are not both 0 at the same time);

[0041] R 1 is one of hydroxyl, methyl, vinyl, and phenyl;

[0042] R 2 is obtained by hydrosilylation of a hydrogen-containing silicone oil with alkoxy groups and a vinyl silicone oil, specifically one of several structures of formula (II) - formula (VI). In formula (IV), x is an integer between 1 and 12.

[0043]

[0044]

[0045] The catalyst is an organotin catalyst, and specifically, one of dibutyltin dilaurate, dioctyltin dilaurate, and dibutyltin didecanoate can be selected.

[0046] A preparation method of a two-component high thermal conductivity silicone potting adhesive includes the following steps:

[0047] Step 1: Directly blend terminal hydroxyl polydimethylsiloxane, thermal conductive powder, and pigment, and stir evenly at high speed.

[0048] Step 2: Shovel the edges of the mixture obtained in Step 1, stir evenly under vacuum, and then discharge to obtain the A component of the high thermal conductivity potting adhesive.

[0049] Step 3: Stir the cross-linking agent, silane coupling agent, anti-settling silicone oil, and catalyst evenly at low speed under vacuum to obtain the B component of the high thermal conductivity potting adhesive.

[0050] Example 1

[0051] A preparation method of a two-component high thermal conductivity silicone potting adhesive includes the following steps:

[0052] Component A: Add 10 parts of 1000 mPa·s polydimethylsiloxane, 300 parts of thermal conductive powder, and 1 part of carbon black paste into a planetary mixer in sequence, and stir at normal pressure for 20 min. After stopping the machine and scraping the edges, keep the vacuum and stir for 15 min under the condition that the vacuum degree ≤ -0.086 MPa. After stopping the machine, add the remaining 40 parts of 500 mPa·s polydimethylsiloxane and 1 part of 2000 mPa·s dimethyl silicone oil, stir at normal pressure for 10 min. After stopping the machine and scraping the edges, evacuate and stir for 30 min to obtain Component A.

[0053] Component B: Prepare 5 parts of vinyltriethoxysilane, 10 parts of phenyltriethoxysilane, 5 parts of γ-aminopropyltriethoxysilane, 5 parts of γ-aminoethylaminopropyltrimethoxysilane, 20 parts of γ-(2,3-epoxypropoxy)propyltrimethoxysilane, 70 parts of anti-settling silicone oil (the anti-settling silicone oil is as shown in Formula ① below, m = 90, n = 1500, and the viscosity of the anti-settling silicone oil is 30000 mPa·s), and 0.1 part of dioctyltin dilaurate respectively. Start the vacuum pump of the reaction kettle and open the vacuum valve to evacuate. Quickly suck each raw material into the reaction kettle under negative pressure. After the feeding is completed, close the feeding valve and keep the vacuum and stir for 25 min to obtain Component B.

[0054]

[0055] Preparation process of the anti-settling silicone oil of Formula ①:

[0056] (1) Add the calculated amount of hydrogen-containing silicone oil into a dry four-necked flask, and add an appropriate amount of toluene and the calculated amount of catalyst chloroplatinic acid;

[0057] (2) Raise the temperature (100 - 110 °C), and slowly drop vinyltrimethoxysilane under stirring or reflux conditions. The reaction formula of the target product is as shown in Formula (Ⅶ);

[0058] (3) Separation: Remove the solvent and residual amine by vacuum distillation.

[0059]

[0060] Comparative Example 1

[0061] The difference between this comparative example and Example 1 is only that: the anti-settling silicone oil in Example 1 is replaced with an equal amount of 30000 mPa·s dimethyl silicone oil.

[0062] Example 2

[0063] A preparation method of a two-component high thermal conductive silicone potting adhesive, comprising the following steps:

[0064] Component A: Add 10 parts of 500 mPa·s hydroxyl-terminated polydimethylsiloxane, 10 parts of 20,000 mPa·s hydroxyl-terminated polydimethylsiloxane, 100 parts of heat-conducting powder, and 5 parts of titanium white paste into a planetary mixer in sequence, and stir at normal pressure for 20 min. After stopping the machine and scraping the edges, keep stirring under vacuum at a vacuum degree ≤ -0.086 MPa for 15 min. After stopping the machine, add the remaining 30 parts of 500 mPa·s hydroxyl-terminated polydimethylsiloxane and 10 parts of 50 mPa·s dimethyl silicone oil, stir at normal pressure for 10 min, and after stopping the machine and scraping the edges, stir under vacuum for 30 min to obtain Component A.

[0065] Component B: Prepare 5 parts of methyltrimethoxysilane, 5 parts of phenyltrimethoxysilane, 10 parts of γ-aminopropyltriethoxysilane, 2 parts of γ-aminoethylaminopropyltrimethoxysilane, 8 parts of γ-(2,3-epoxypropoxy)propyltrimethoxysilane, 40 parts of anti-settling silicone oil (the anti-settling silicone oil is shown in formula ② below, where m = 300 and the viscosity of the anti-settling silicone oil is 25,000 mPa·s), and 0.5 part of dibutyltin dilaurate respectively. Start the vacuum pump of the reaction kettle and open the vacuum valve to pump vacuum. Quickly suck each raw material into the reaction kettle under negative pressure. After the feeding is completed, close the feeding valve and keep stirring under vacuum for 25 min to obtain Component B.

[0066]

[0067] Comparative Example 2

[0068] In this comparative example, the only difference from Example 2 is that the anti-settling silicone oil in Example 2 is replaced with an equal amount of 25,000 mPa·s dimethyl silicone oil.

[0069] Example 3

[0070] A preparation method of a two-component high heat-conducting silicone potting adhesive comprises the following steps:

[0071] Component A: Add 10 parts of 700 mPa·s polydimethylsiloxane, 10 parts of 10,000 mPa·s polydimethylsiloxane, 200 parts of heat-conducting powder, and 5 parts of titanium white paste into a planetary mixer in sequence, and stir at normal pressure for 20 min. After stopping the machine and scraping the edges, keep stirring under vacuum at a vacuum degree ≤ -0.086 MPa for 15 min. After stopping the machine, add 10 parts of 1000 mPa·s polydimethylsiloxane and 5 parts of 100 mPa·s dimethyl silicone oil, stir at normal pressure for 10 min, and after stopping the machine and scraping the edges, stir under vacuum for 30 min to obtain Component A.

[0072] Component B: Weigh 5 parts of methyltrimethoxysilane, 25 parts of vinyltriethoxysilane, 15 parts of γ-aminopropyltriethoxysilane, 5 parts of γ-aminoethylaminopropyltrimethoxysilane, 10 parts of γ-(2,3-epoxypropoxy)propyltrimethoxysilane, 50 parts of anti-settling silicone oil (the anti-settling silicone oil is as shown in formula ③ below, n = 500, and the viscosity of the anti-settling silicone oil is 1000 mPa·s), and 0.5 part of dibutyltin dilaurate respectively. Start the vacuum pump of the reaction kettle and open the vacuum valve to evacuate. Rapidly suck each raw material into the reaction kettle under negative pressure. After the feeding is completed, close the feeding valve, keep the vacuum and stir for 25 min to obtain Component B.

[0073]

[0074] Comparative Example 3

[0075] The difference between this comparative example and Example 3 is that the anti-settling silicone oil in Example 3 is replaced with an equal amount of dimethyl silicone oil with a viscosity of 1000 mPa·s.

[0076] Example 4

[0077] A method for preparing a two-component high thermal conductivity silicone potting adhesive, comprising the following steps:

[0078] Component A: Add 10 parts of polydimethylsiloxane with a viscosity of 1000 mPa·s, 200 parts of thermal conductive powder, and 1 part of carbon black paste to a planetary mixer in sequence, and stir at normal pressure for 20 min. After stopping the machine and scraping the edges, keep the vacuum and stir for 15 min under the condition that the vacuum degree ≤ -0.086 MPa. Stop the machine and add the remaining 30 parts of polydimethylsiloxane with a viscosity of 500 mPa·s and 5 parts of dimethyl silicone oil with a viscosity of 2000 mPa·s, stir at normal pressure for 10 min, stop the machine and scrape the edges, then evacuate and stir for 30 min to obtain Component A.

[0079] Component B: Weigh 15 parts of vinyltriethoxysilane, 5 parts of phenyltrimethoxysilane, 12 parts of γ-aminopropyltriethoxysilane, 4 parts of γ-aminoethylaminopropyltrimethoxysilane, 5 parts of γ-(2,3-epoxypropoxy)propyltrimethoxysilane, 50 parts of anti-settling silicone oil (the anti-settling silicone oil is as shown in formula ④ below, m = 100, n = 200, and the viscosity of the anti-settling silicone oil is 20000 mPa·s), and 0.2 part of dibutyltin dilaurate respectively. Start the vacuum pump of the reaction kettle and open the vacuum valve to evacuate. Rapidly suck each raw material into the reaction kettle under negative pressure. After the feeding is completed, close the feeding valve, keep the vacuum and stir for 25 min to obtain Component B.

[0080]

[0081] Comparative Example 4

[0082] The difference between this comparative example and Example 4 is that the anti-settling silicone oil in Example 4 is replaced with an equal amount of dimethyl silicone oil with a viscosity of 20000 mPa·s.

[0083] Example 5

[0084] A preparation method of a two-component highly thermally conductive silicone potting adhesive, comprising the following steps:

[0085] Component A: Add 10 parts of hydroxyl-terminated polydimethylsiloxane with a viscosity of 500 mPa·s, 10 parts of hydroxyl-terminated polydimethylsiloxane with a viscosity of 2000 mPa·s, 250 parts of thermally conductive powder, and 5 parts of titanium white paste into a planetary mixer in sequence, and stir at normal pressure for 20 min. After stopping the machine and scraping the edges, keep the vacuum and stir for 15 min under the condition that the vacuum degree ≤ -0.086 MPa. After stopping the machine, add the remaining 30 parts of hydroxyl-terminated polydimethylsiloxane with a viscosity of 500 mPa·s and 10 parts of dimethyl silicone oil with a viscosity of 500 mPa·s, stir at normal pressure for 10 min, stop the machine and scrape the edges, and then stir under vacuum for 30 min to obtain Component A.

[0086] Component B: Prepare 13 parts of vinyltrimethoxysilane, 10 parts of phenyltriethoxysilane, 10 parts of γ-aminopropyltriethoxysilane, 2 parts of γ-aminoethylaminopropyltrimethoxysilane, 9 parts of γ-(2,3-epoxypropoxy)propyltrimethoxysilane, 45 parts of anti-settling silicone oil (as shown in formula ⑤ below, m = 150, n = 200, viscosity is 15000 mPa·s), and 0.5 part of dibutyltin dilaurate respectively. Start the vacuum pump of the reaction kettle and open the vacuum valve to draw vacuum. Rapidly draw each raw material into the reaction kettle under negative pressure. After the feeding is completed, close the feeding valve, keep the vacuum and stir for 25 min to obtain Component B.

[0087]

[0088] Comparative Example 5

[0089] The difference between this comparative example and Example 5 is that the anti-settling silicone oil in Example 5 is replaced with an equal amount of dimethyl silicone oil with a viscosity of 20000 mPa·s.

[0090] Example 6

[0091] A preparation method of a two-component highly thermally conductive silicone potting adhesive, comprising the following steps:

[0092] Component A: Add 10 parts of 1500 mPa·s polydimethylsiloxane, 10 parts of 700 mPa·s polydimethylsiloxane, 150 parts of thermal conductive powder, and 5 parts of titanium white paste into a planetary mixer in sequence, and stir at normal pressure for 20 min. After stopping the machine and scraping the edges, keep stirring under vacuum at a vacuum degree ≤ -0.086 MPa for 15 min. After stopping the machine, add 10 parts of 1500 mPa·s polydimethylsiloxane and 5 parts of 100 mPa·s dimethyl silicone oil, stir at normal pressure for 10 min, stop the machine, scrape the edges, and then stir under vacuum for 30 min to obtain Component A.

[0093] Component B: Prepare 2 parts of propyltrimethoxysilane, 2 parts of tetraethyl orthosilicate, 1 part of polymethyltriethoxysilane, 0.2 part of N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane, 0.5 part of N-(β-aminoethyl)-γ-aminopropyltriethoxysilane, 0.3 part of γ-aminopropyltriethoxysilane, 100 parts of anti-settling silicone oil (as shown in formula ⑥ below, m = 15, n = 25, viscosity is 100 mPa·s), and 0.2 part of dibutyltin dilaurate respectively. Start the vacuum pump of the reaction kettle and open the vacuum valve to pump vacuum. Rapidly suck each raw material into the reaction kettle under negative pressure. After the feeding is completed, close the feeding valve and keep stirring under vacuum for 25 min to obtain Component B.

[0094]

[0095] Comparative Example 6

[0096] The difference between this comparative example and Example 6 is that in this comparative example, the anti-settling silicone oil in Example 6 is replaced with an equal amount of 100 mPa·s dimethyl silicone oil.

[0097] Example 7

[0098] A preparation method of a two-component high thermal conductive silicone potting adhesive, comprising the following steps:

[0099] Component A: Add 15 parts of 500 mPa·s hydroxyl-terminated polydimethylsiloxane, 300 parts of thermal conductive powder, and 5 parts of titanium white paste into a planetary mixer in sequence, and stir at normal pressure for 20 min. After stopping the machine and scraping the edges, keep stirring under vacuum at a vacuum degree ≤ -0.086 MPa for 15 min. After stopping the machine, add the remaining 35 parts of 500 mPa·s hydroxyl-terminated polydimethylsiloxane and 10 parts of 50 mPa·s dimethyl silicone oil, stir at normal pressure for 10 min, stop the machine, scrape the edges, and then stir under vacuum for 30 min to obtain Component A.

[0100] Component B: Weigh 15 parts of propyltriethoxysilane, 5 parts of octyltrimethoxysilane, 5 parts of tetraethyl orthosilicate, 12 parts of γ-aminopropyltriethoxysilane, 4 parts of γ-aminoethylaminopropyltrimethoxysilane, 5 parts of γ-(2,3-epoxypropoxy)propyltrimethoxysilane, 20 parts of anti-settling silicone oil (as shown in formula ⑦ below, m = 500, n = 1000, viscosity is 200000 mPa·s), and 0.2 parts of dibutyltin dilaurate respectively. Start the vacuum pump of the reaction kettle and open the vacuum valve to evacuate. Quickly suck each raw material into the reaction kettle under negative pressure. After the feeding is completed, close the feeding valve and stir under vacuum for 25 minutes to obtain Component B.

[0101]

[0102] Comparative Example 7

[0103] The difference between this comparative example and Example 7 is that in this comparative example, the anti-settling silicone oil in Example 7 is replaced with an equal amount of dimethyl silicone oil with a viscosity of 200000 mPa·s.

[0104] Perform performance tests on the high thermal conductivity silicone rubber potting adhesives obtained from the above examples and comparative examples. The specific test methods are as follows:

[0105] 1) Test the thermal conductivity of the prepared high thermal conductivity potting adhesive according to ISO 22007-2 "Plastics - Determination of Thermal Conductivity and Thermal Diffusivity".

[0106] 2) Test the viscosity of the prepared high thermal conductivity potting adhesive according to GB / T 2794 "Viscosity Test Method". Each group conducts three repeated experiments, and the results are shown in Table 1 and Table 2.

[0107] Table 1 Performance Tests of Examples 1 - 7

[0108]

[0109] Table 2 Storage Performance of Component B in Comparative Examples 1 - 7

[0110]

[0111] From the above performance data, it can be seen that the two-component high thermal conductivity silicone rubber potting adhesive provided by the present invention has a low mixing ratio and a large adjustable viscosity range, which can meet the usage requirements of current mainstream commercially available glue coating equipment. Compared with Comparative Examples 1 - 7, the Component B provided by the present invention has no stratification or sedimentation after being placed at normal temperature for 12 months, and its storage performance is very stable. In the Component B of the comparative examples, dimethyl silicone oil with the same viscosity is used to replace the anti-settling silicone oil. Except for the storage stability, the potting performance of the comparative examples is the same as that of the examples in the initial state, but after storage, the Component B in the comparative examples is stratified and cannot be used normally.

[0112] The above are only embodiments of the present invention, and common general technical solutions and / or features in the solutions are not described in detail herein. It should be noted that for those skilled in the art, without departing from the technical solution of the present invention, several deformations and improvements can be made, which should also be regarded as the protection scope of the present invention, and these will not affect the implementation effect of the present invention and the practicability of the patent. The protection scope required by this application shall be subject to the content of its claims, and the specific implementation manners and the like recorded in the specification can be used to interpret the content of the claims.

Claims

1. A two-component high thermal conductivity silicone potting adhesive, characterized in that: It includes component A and component B. Component A, by mass parts, includes the following raw materials: 30-50 parts of hydroxyl-terminated polydimethylsiloxane, 100-300 parts of thermal conductive powder, 1-10 parts of dimethyl silicone oil, 1-5 parts of pigment; Component B, by mass parts, includes the following raw materials: 5-30 parts of cross-linking agent, 1-30 parts of silane coupling agent, 20-100 parts of anti-settling silicone oil, 0.1-0.5 part of catalyst; The viscosity of the anti-settling silicone oil at 25 °C is 100-200000 mPa·s, and the structure of the anti-settling silicone oil is as shown in formula (I): Formula (I) In formula (I), m is an integer between 15 and 500, and n is an integer between 0 and 1500; R 1 is one of hydroxyl, methyl, vinyl, and phenyl; R 2 is obtained by hydrosilylation of hydrogen-containing silicone oil with alkoxy groups and vinyl silicone oil; the mass ratio of component A to component B is (1 - 7):

1.

2. A two-component high thermal conductivity silicone potting adhesive according to claim 1, characterized in that: The R 2 is one of several structures of Formula (II) - Formula (VI); In formula (IV), x is an integer between 1 and 12.

3. A two-component high thermal conductivity silicone potting adhesive according to claim 2, characterized in that: The viscosity of the hydroxyl-terminated polydimethylsiloxane is 500-20000 mPa·s, and the viscosity of the dimethyl silicone oil is 50-2000 mPa·s.

4. A two-component high thermal conductivity silicone potting adhesive according to claim 3, characterized in that: The thermal conductive powder is alumina or aluminum hydroxide; the pigment is titanium white paste or carbon black paste; the cross-linking agent is a commercially available alkoxysilane cross-linking agent, which is at least one of methyltrimethoxysilane, methyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, tetraethyl orthosilicate, polymethyltriethoxysilane, propyltrimethoxysilane, propyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, octyltrimethoxysilane.

5. A two-component high thermal conductivity silicone potting adhesive according to claim 4, characterized in that: The silane coupling agent is at least one of γ-aminopropyltriethoxysilane, γ-aminoethylaminopropyltrimethoxysilane, N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane, N-(β-aminoethyl)-γ-aminopropyltriethoxysilane, γ-(2,3-epoxypropoxy)propyltrimethoxysilane.

6. A two-component high thermal conductivity silicone potting adhesive according to claim 5, characterized in that: The catalyst is an organotin catalyst, and the organotin catalyst is one of dibutyltin dilaurate, dioctyltin dilaurate and dibutyltin didecanoate.

7. A preparation method of a two-component high thermal conductivity silicone potting adhesive according to any one of claims 1-6, characterized in that, comprises the following steps: Step 1, mix and stir the hydroxyl-terminated polydimethylsiloxane, thermal conductive powder and pigment to obtain a mixed material; Step 2, after the mixed material obtained in Step 1 is trimmed and stirred evenly, discharge it to obtain component A of the high thermal conductivity potting adhesive; Step 3, stir the cross-linking agent, silane coupling agent, anti-settling silicone oil and catalyst evenly to obtain component B of the high thermal conductivity potting adhesive.

8. A preparation method of a two-component high thermal conductivity silicone potting adhesive according to claim 7, characterized in that: The stirring processes in Step 1 and Step 2 are both carried out under vacuum conditions.

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