Waterproof heat-conducting bonding pouring sealant and preparation method thereof

Abstract

The invention particularly relates to a waterproof heat-conducting bonding pouring sealant and a preparation method thereof. The waterproof heat-conducting bonding pouring sealant comprises a component A and a component B, wherein the component A comprises vinyl polydimethylsiloxane, polymethylhydrosiloxane, a heat-conducting filler, color paste, an inhibitor and a tackifier; and the component B comprises vinyl polydimethylsiloxane, a heat-conducting filler and a catalyst. Vinyl phenyl siloxane is selected as a powder treating agent, so that the compatibility of powder and a system is improved, and a benzene ring can be introduced into molecules through a hydrosilylation reaction; by autonomously synthesizing the tackifier, adopting polymethylhydrosiloxane with higher hydrogen content as a reaction raw material, introducing an epoxy group and an alkoxy group into a molecular chain segment through hydrosilylation reaction, increasing a plurality of reaction active sites, and quickly reacting with a hydroxyl group on the surface of a base material to achieve a quick bonding effect after being in contact with the bonding base material; and water vapor is effectively prevented from entering the electronic component from a bonding interface.

Description

Technical Field

[0001] This invention relates to the field of silicone rubber and adhesives, specifically to a waterproof and thermally conductive adhesive potting compound and its preparation method. Background Technology

[0002] As electronic and electrical equipment rapidly evolves towards miniaturization, high power density, and high integration, the heat generated increases dramatically. Effective thermal management has become a core challenge in ensuring equipment reliability, stability, and lifespan. Simultaneously, these devices operate in increasingly complex environments, such as direct sunlight and extreme high temperature and humidity. This necessitates that the core electronic components of these devices possess excellent waterproof, moisture-proof, corrosion-resistant, and chemical-resistant capabilities. The most common solution on the market is to pot a layer of thermally conductive adhesive on the surface of the component to achieve heat dissipation, insulation, and waterproofing. However, different adhesive systems face their own problems. Epoxy potting compounds are hard and brittle, with high internal stress and poor resistance to thermal cycling (prone to cracking), poor UV resistance (prone to yellowing), and difficult to repair. Polyurethane potting compounds have poor high temperature and humidity resistance, are prone to bubbling, and have average chemical resistance. On the other hand, silicone potting compounds have good elasticity, low stress, excellent high and low temperature resistance, good weather resistance, aging resistance, stable electrical properties, and are chemically inert and non-corrosive. However, their adhesion is poor, and they often need to be used in conjunction with a primer. Moreover, after the adhesive cures, moisture can easily penetrate the adhesive surface and seep into the electronic components, affecting the product's lifespan. Therefore, improving the adhesion of silicone potting compounds and reducing their moisture permeability is the key to improving the overall reliability of electronic components.

[0003] Chinese patent CN108893092A discloses a low-to-medium temperature rapid-curing addition-type silicone adhesive rubber. It requires curing at 100-120℃ to achieve the desired bonding effect, increasing energy consumption. Furthermore, many plastic components cannot withstand high temperatures, limiting their use. Chinese patent CN119799276A discloses a high-adhesion silicone potting compound for LED displays and its preparation method. By adding silicone resin and adhesion promoters, its mechanical and adhesive properties are significantly improved. While it can prevent moisture from penetrating through the bonding interface, it cannot prevent moisture from seeping into the components from the adhesive surface. Summary of the Invention

[0004] To address the shortcomings of the prior art, one objective of this invention is to provide a waterproof and thermally conductive adhesive potting compound. This waterproof and thermally conductive adhesive potting compound possesses excellent bonding performance and low water vapor permeability, effectively solving the problems of water vapor seeping into the bonding interface and penetrating the component interior from the adhesive surface, thus achieving a superior waterproof effect.

[0005] Another objective of this invention is to provide a method for preparing a waterproof and thermally conductive adhesive potting compound. The method for preparing the waterproof and thermally conductive adhesive potting compound is stable, easy to operate and control, and conducive to industrial production.

[0006] One of the objectives of this invention is achieved through the following technical solution: a waterproof and thermally conductive adhesive potting compound, comprising component A and component B, wherein component A comprises vinyl polydimethylsiloxane, polymethylhydrosiloxane, thermally conductive filler, colorant, inhibitor and tackifier; and component B comprises vinyl polydimethylsiloxane, thermally conductive filler and catalyst.

[0007] Furthermore, the waterproof and thermally conductive adhesive potting compound comprises component A and component B; component A comprises the following raw materials in parts by weight: 20-30 parts of vinyl polydimethylsiloxane, 5-20 parts of polymethylhydrosiloxane, 65-80 parts of thermally conductive filler, 0.01-1 parts of colorant, 0.001-0.1 parts of inhibitor, and 0.5-2 parts of tackifier; Further, component B comprises the following raw materials in parts by weight: 35-45 parts of vinyl polydimethylsiloxane, 65-80 parts of thermally conductive filler, and 0.1-0.5 parts of catalyst.

[0008] Further, the vinyl-terminated polydimethylsiloxane in components A and B is a vinyl-terminated polydimethylsiloxane with a viscosity of 50-1000 cps, measured at 25°C. Preferably, the viscosity of the vinyl-terminated polydimethylsiloxane is 50-500 cps. Components A and B may use the same or different vinyl-terminated polydimethylsiloxanes.

[0009] Furthermore, the polymethylhydrosiloxane in component A is composed of one or more polymethylhydrosiloxanes with a hydrogen content of 0.05-1.0%. Preferably, the polymethylhydrosiloxane has a hydrogen content of 0.05-0.5%.

[0010] Furthermore, the thermally conductive fillers in components A and B are modified thermally conductive fillers, which are formed by compounding initial thermally conductive fillers and treating them with a modifier. The initial thermally conductive fillers are at least one selected from alumina, silica powder, aluminum hydroxide, calcium carbonate, and zinc oxide. Preferably, the initial thermally conductive fillers in components A and B are compounded from alumina, silica powder, and aluminum hydroxide in a mass ratio of 1-2:4-5:1-2.

[0011] Further, the modifier is at least one selected from trimethoxy(4-vinylphenyl)silane, vinylphenyldiethoxysilane, [2-[3(or 4)-vinylphenyl]ethyl]trimethoxysilane, and triethoxy(1-phenylvinyl)silane. Preferably, the modifier is at least one selected from trimethoxy(4-vinylphenyl)silane and [2-[3(or 4)-vinylphenyl]ethyl]trimethoxysilane.

[0012] The thermally conductive fillers in components A and B of this invention are modified with vinylphenylsilane coupling agents, which helps to improve the compatibility between the powder and the system, and can reduce the water vapor permeability of the silicone matrix and improve the waterproofness of the silicone matrix.

[0013] Furthermore, the color paste in component A is a black color paste, which is at least one of iron black and carbon black.

[0014] Further, the inhibitor in component A is at least one selected from ethynylcyclohexanol, methylbutynol, and methylvinylcyclosiloxane. Preferably, the inhibitor is methylbutynol or ethynylcyclohexanol.

[0015] Furthermore, the tackifier in component A contains multiple epoxy groups and multiple alkoxy groups in its structure. The tackifier is a silane coupling agent containing multiple epoxy groups and multiple alkoxy groups.

[0016] Furthermore, the preparation method of the thickener includes the following steps: (1) Add end-side hydrogen-containing silicone oil and platinum catalyst to the reaction vessel and stir evenly; then add allyl glycidyl ether dropwise so that the molar ratio of Si-H to vinyl in the system is 1.1-2.0, stirring while adding dropwise, and after the addition is complete, raise the temperature to 80-120℃ and react for 1-5 hours. (2) Introduce nitrogen gas and add vinylsiloxane to the reaction vessel so that the molar ratio of vinyl to residual Si-H is 1:1.01-1.1, and react for 3-8 hours; (3) The mixed liquid obtained after the reaction is treated to remove the residual platinum in the system.

[0017] Furthermore, the catalyst in component B is a platinum catalyst, specifically a Speier catalyst or a Castells catalyst. Preferably, the catalyst is a Castells platinum catalyst.

[0018] The tackifier in this invention contains multiple active alkoxy and epoxy groups in its molecular structure, which enhances its adhesion to Al and PCBA boards and effectively prevents water molecules from penetrating from the adhesive-substrate interface into the interior of electronic components. The thermally conductive filler used is modified with a vinylphenyl silane coupling agent, increasing the compatibility between the filler and the matrix resin. The vinyl groups in the coupling agent can undergo a hydrosilylation reaction with the crosslinking agent polymethylhydrosiloxane, introducing phenyl groups into the siloxane backbone. The low polarity and steric hindrance effect of the phenyl groups also effectively hinder the penetration of water molecules into the silicone backbone, achieving a waterproof effect.

[0019] Another objective of this invention is achieved through the following technical solution: a method for preparing a waterproof and thermally conductive silicone adhesive potting compound, comprising the following steps: Preparation of Component A: First, a portion of vinyl polydimethylsiloxane and thermally conductive filler are stirred evenly under high temperature and vacuum conditions. After the material is cooled to room temperature, the remaining vinyl polydimethylsiloxane, methylhydrosiloxane, inhibitor, color paste and thickener are added and stirred evenly under vacuum conditions to obtain Component A. Preparation of component B: First, vinyl polydimethylsiloxane and thermally conductive filler are stirred evenly under high temperature and vacuum conditions. After the material is cooled to room temperature, the remaining vinyl polydimethylsiloxane and catalyst are added, and the mixture is stirred evenly under vacuum conditions to obtain component B.

[0020] Furthermore, in the preparation method of the waterproof and thermally conductive silicone adhesive potting compound, the mixing equipment can be a dual planetary mixer or a kneader.

[0021] Furthermore, in the preparation steps of components A and B, the vacuum degree of vacuum stirring is set to less than -0.08 MPa; in the preparation process of components A and B, the first stirring is carried out by kneading machine at high temperature to obtain the base material, with a speed of 20-40 Hz, a temperature of 150-200℃, and a time of 1-2 h; the second stirring is carried out by double planetary power mixing machine to make the glue, with a stirring speed of 300-600 r / min and a stirring time of 30-60 min.

[0022] Furthermore, in the preparation method of component A, vinyl polydimethylsiloxane and thermally conductive filler are added to a kneader, the temperature is raised to 150-200℃, the vacuum degree is <-0.08MPa, the stirring speed is 20-40Hz, and the stirring reaction is carried out for 1-2 hours to obtain a semi-finished base material. After cooling to room temperature, it is transferred to a double planetary power mixer, and the remaining polydimethylsiloxane, polymethylhydrosiloxane, color paste, thickener, and inhibitor are added. The mixture is stirred under vacuum for 30-60 minutes, the vacuum degree is <-0.08MPa, and the stirring speed is 300-600r / min to obtain component A.

[0023] Furthermore, in the preparation method of component B, vinyl polydimethylsiloxane and thermally conductive filler are added to a kneader, the temperature is raised to 150-200℃, the vacuum degree is <-0.08MPa, the stirring speed is 20-40Hz, and the stirring reaction is carried out for 1-2 hours to obtain a semi-finished base material. After cooling to room temperature, it is transferred to a double planetary power mixer, and the remaining polydimethylsiloxane and catalyst are added. The mixture is stirred under vacuum for 30-60 minutes, the vacuum degree is <-0.08MPa, and the stirring speed is 300-600r / min to obtain component B.

[0024] Compared with the prior art, the present invention has achieved at least the following beneficial effects: 1. This invention designs a waterproof and thermally conductive silicone adhesive potting compound and its preparation method. By selecting vinylphenylsiloxane as a powder treatment agent, not only is the compatibility between the powder and the system increased, but also the benzene ring can be introduced into the molecular backbone through hydrosilylation reaction. The low polarity and steric hindrance effect of phenyl also effectively hinder the penetration of water molecules into the silicone backbone, reduce the water vapor permeability of the silicone body, and improve the waterproofness of the silicone body.

[0025] 2. This invention uses a self-synthesized tackifier, employing polymethylhydrosiloxane with a high hydrogen content as the reactant. Through hydrosilylation reaction, a large number of epoxy and alkoxy groups are introduced into the molecular chain segment, increasing multiple reactive sites. After contacting the adhesive substrate, it can quickly react with the hydroxyl groups on the substrate surface to achieve rapid bonding and effectively prevent moisture from penetrating into the electronic components from the bonding interface. Detailed Implementation

[0026] To facilitate understanding by those skilled in the art, the present invention will be further described below with reference to embodiments. The content mentioned in the embodiments is not intended to limit the present invention.

[0027] In some embodiments of the present invention, a waterproof and thermally conductive adhesive potting compound is provided. The potting compound is a two-component adhesive, comprising component A and component B. Component A comprises vinyl polydimethylsiloxane, polymethylhydrosiloxane, thermally conductive filler, colorant, inhibitor, and tackifier. Component B comprises vinyl polydimethylsiloxane, thermally conductive filler, and catalyst.

[0028] In some embodiments of the present invention, the waterproof and thermally conductive adhesive potting compound includes component A and component B; component A includes the following raw materials in parts by weight: 20-30 parts of vinyl polydimethylsiloxane, 5-20 parts of polymethylhydrosiloxane, 65-80 parts of thermally conductive filler, 0.01-1 parts of black pigment, 0.001-0.1 parts of inhibitor, and 0.5-2 parts of tackifier; Component B comprises the following raw materials in parts by weight: 35-45 parts of vinyl polydimethylsiloxane, 65-80 parts of thermally conductive filler, and 0.1-0.5 parts of catalyst.

[0029] The waterproof and thermally conductive adhesive potting compound of the present invention can be cured at room temperature or cured rapidly by heating, so as to solve the problem of moisture seeping into the bonding interface and the adhesive surface penetrating into the interior of the components, thus achieving the purpose of dual waterproofing.

[0030] In some embodiments of the present invention, the vinyl-terminated polydimethylsiloxane in components A and B is a vinyl-terminated polydimethylsiloxane with a viscosity of 50-1000 cps (25°C). Preferably, the viscosity of the vinyl-terminated polydimethylsiloxane is 50-500 cps. The vinyl-terminated polydimethylsiloxane used in components A and B may be the same or different.

[0031] Furthermore, the polymethylhydrosiloxane in component A is composed of one or more polymethylhydrosiloxanes with a hydrogen content of 0.05-1.0%. Preferably, the polymethylhydrosiloxane used in the embodiments of the present invention has a hydrogen content of 0.05-0.5%.

[0032] Furthermore, the thermally conductive fillers in components A and B are modified thermally conductive fillers, which are formed by compounding initial thermally conductive fillers and treating them with a modifier. The initial thermally conductive fillers are at least one selected from alumina, silica powder, aluminum hydroxide, calcium carbonate, and zinc oxide. Preferably, the initial thermally conductive fillers in components A and B are compounded from alumina, silica powder, and aluminum hydroxide in a mass ratio of 1-2:4-5:1-2.

[0033] In some embodiments of the present invention, the mass ratio of alumina, silica powder and aluminum hydroxide in the initial thermally conductive fillers of components A and B is 1:5:1, 2:4:1 or 1:4:2, preferably 1:5:1.

[0034] In some embodiments of the present invention, the modifier is at least one selected from trimethoxy(4-vinylphenyl)silane, vinylphenyldiethoxysilane, [2-[3(or 4)-vinylphenyl]ethyl]trimethoxysilane, and triethoxy(1-phenylvinyl)silane. Preferably, the modifier is at least one selected from trimethoxy(4-vinylphenyl)silane or [2-[3(or 4)-vinylphenyl]ethyl]trimethoxysilane.

[0035] In some embodiments of the present invention, a method for preparing a modified thermally conductive filler includes the following steps: The initial thermally conductive filler to be modified is added to a mixer. The initial thermally conductive filler is a mixture of alumina, silica powder, and aluminum hydroxide in a mass ratio of 1-2:4-5:1-2. A modifier is then added to the mixer at a concentration of 0.05-0.2% of the initial thermally conductive filler mass. After dispersion, modified thermally conductive filler powder 1 is obtained. The particle size of the initial thermally conductive filler is 0.1-20 μm. Preferably, the silica powder has a particle size of 1-5 μm, the alumina has a particle size of 8-20 μm, and the aluminum hydroxide has a particle size of 0.1-2 μm.

[0036] Furthermore, the color paste in component A is a black color paste, which is at least one of iron black color paste and carbon black color paste. Preferably, it is a carbon black color paste.

[0037] Further, the inhibitor in component A is at least one selected from ethynylcyclohexanol, methylbutynol, and methylvinylcyclosiloxane. Preferably, the inhibitor is methylbutynol or ethynylcyclohexanol.

[0038] Furthermore, the tackifier in component A contains multiple epoxy groups and multiple alkoxy groups in its structure. The tackifier is a silane coupling agent containing multiple epoxy groups and alkoxy groups.

[0039] In some embodiments of the present invention, the method for preparing the tackifier includes the following steps: (1) Add end-side hydrogen-containing silicone oil and platinum catalyst to the reaction vessel and stir evenly; then add allyl glycidyl ether dropwise so that the molar ratio of Si-H to vinyl in the system is 1.1-2.0, stirring while adding dropwise, and after the addition is complete, raise the temperature to 80-120℃ and react for 1-5 hours. (2) Introduce nitrogen gas and add vinylsiloxane to the reaction vessel so that the molar ratio of vinyl to residual Si-H is 1:1.01-1.1, and react for 3-8 hours; (3) The mixed liquid obtained after the reaction is treated to remove the residual platinum in the system.

[0040] In some embodiments of the present invention, the method for preparing the tackifier includes the following steps: (1) Add 45-50g of end-side hydrogen-containing silicone oil to the reaction vessel, then add 2-4ppm of Castel platinum catalyst, stir for a period of time, and then add allyl glycidyl ether dropwise. The molar ratio of Si-H to vinyl is 1.1-2.0, preferably 1.5-2.0, to ensure that Si-H is in excess. Stir while adding dropwise, and immediately raise the temperature after the dropwise addition is complete. Optionally, the reaction temperature is 80-120℃, preferably 80-100℃, and the reaction time is 1-5h, preferably 2-4h. (2) After purging with nitrogen, add vinylsiloxane to the reaction flask. Optionally, vinyltrimethoxysilane, vinyltriethoxysilane, methylvinyltrimethoxysilane, preferably vinyltrimethoxysilane, methylvinyldimethoxysilane, vinyl to residual Si-H molar ratio is 1.05 to ensure that Si-H is completely reacted. Optionally, the reaction time is 3-8h, preferably 6-8h. (3) After the reaction is complete, a light yellow semi-transparent liquid is obtained. Then, it is poured into a Buchner funnel containing activated carbon for filtration. The filtered liquid is then poured into the Buchner funnel for filtration again. This process is repeated at least 5 times to ensure that the residual platinum in the system is removed.

[0041] Furthermore, in step (1), the hydrogen content of the end-side hydrogen-containing silicone oil is 1.0-1.5%, preferably 1.2-1.5%; Furthermore, the catalyst in component B is a Speier catalyst or a Castells catalyst. Preferably, the catalyst is a Castells platinum catalyst.

[0042] In some embodiments of the present invention, a method for preparing a waterproof and thermally conductive silicone adhesive potting compound includes the following steps: Preparation of Component A: First, stir 50-90% of vinyl polydimethylsiloxane and thermally conductive filler evenly under high temperature and vacuum conditions. After the material cools to room temperature, add the remaining vinyl polydimethylsiloxane, methyl hydrosiloxane, inhibitor, color paste and thickener and stir evenly under vacuum conditions to obtain Component A. Preparation of component B: First, vinyl polydimethylsiloxane and thermally conductive filler are stirred evenly under high temperature and vacuum conditions. After the material is cooled to room temperature, the remaining vinyl polydimethylsiloxane and catalyst are added, and the mixture is stirred evenly under vacuum conditions to obtain component B.

[0043] Furthermore, in the preparation method of the waterproof and thermally conductive silicone adhesive potting compound, the mixing equipment can be a dual planetary mixer or a kneader.

[0044] Furthermore, in the preparation steps of components A and B, the vacuum degree of vacuum stirring is set to less than -0.08 MPa; the first stirring uses a kneader to obtain the base material at high temperature, with a rotation speed of 20-40 Hz, a temperature of 150-200℃, and a time of 1-2 hours; the second stirring uses a dual planetary mixer to reconstitute the adhesive, with a stirring speed of 300-600 r / min and a stirring time of 30-60 minutes. Components A and B are mixed before use of the potting compound.

[0045] In some embodiments of the present invention, in the preparation method of component A, vinyl polydimethylsiloxane and thermally conductive filler are added to a kneader, the temperature is raised to 150-200°C, the vacuum degree is <-0.08MPa, the stirring speed is 20-40Hz, and the stirring reaction is carried out for 1-2 hours to obtain a semi-finished base material. After cooling to room temperature, it is transferred to a double planetary power mixer, and the remaining polydimethylsiloxane, polymethylhydrosiloxane, color paste, thickener, and inhibitor are added. The mixture is stirred under vacuum for 30-60 minutes, the vacuum degree is <-0.08MPa, and the stirring speed is 300-600r / min to obtain component A.

[0046] In some embodiments of the present invention, in the preparation method of component B, vinyl polydimethylsiloxane and thermally conductive filler are added to a kneader, the temperature is raised to 150-200°C, the vacuum degree is <-0.08MPa, the stirring speed is 20-40Hz, and the stirring reaction is carried out for 1-2 hours to obtain a semi-finished base material; after cooling to room temperature, it is transferred to a double planetary power mixer, the remaining polydimethylsiloxane and catalyst are added, and the mixture is stirred under vacuum for 30-60 minutes, the vacuum degree is <-0.08MPa, and the stirring speed is 300-600r / min to obtain component B.

[0047] Example 1 I. Modification of thermally conductive fillers 1. A method for preparing modified thermally conductive filler 1, comprising the following steps: Add the initial thermally conductive filler to be modified into a high-speed mixer. The initial thermally conductive filler is prepared according to the ratio of alumina:silica powder:aluminum hydroxide = 1:5:1. Then add trimethoxy(4-vinylphenyl)silane to the high-speed mixer, accounting for 0.1% of the mass of the initial thermally conductive filler powder. Press the start button, and the mixer runs at a speed of 25Hz for 200s. After changing the operating frequency to 35Hz for 150s, the powder of modified thermally conductive filler 1 is obtained.

[0048] 2. The preparation method of modified thermally conductive filler 2 includes the following steps: Add the initial thermally conductive filler to be modified into a high-speed mixer. The initial thermally conductive filler is prepared according to the ratio of alumina:silica powder:aluminum hydroxide = 1:5:1. Then add [2-[3(or 4)-vinylphenyl]ethyl]trimethoxysilane, accounting for 0.1% of the mass of the initial modified filler, into the high-speed mixer. Press the start button, and the mixer runs at a speed of 25Hz for 200s. After changing the operating frequency to 35Hz for 150s, the powder of modified thermally conductive filler 2 is obtained.

[0049] 3. The preparation method of modified thermally conductive filler 3 includes the following steps: Add the initial thermally conductive filler to be modified into a high-speed mixer. The initial thermally conductive filler is prepared according to the ratio of alumina:silica powder:aluminum hydroxide = 1:5:1. Then add dodecyltrimethoxysilane to the high-speed mixer, accounting for 0.1% of the mass of the initial modified filler. Press the start button, and the mixer runs at a speed of 25Hz for 200s. After changing the operating frequency to 35Hz for 150s, the powder of modified thermally conductive filler 3 is obtained.

[0050] 4. The preparation method of modified thermally conductive filler 4 includes the following steps: Add the initial thermally conductive filler to be modified into a high-speed mixer. The initial thermally conductive filler is prepared according to the ratio of alumina:silica powder:aluminum hydroxide = 1:5:1. Then add 50CS methyl silicone oil to the high-speed mixer, accounting for 0.1% of the mass of the initial modified filler. Press the start button, and the mixer runs at a speed of 25Hz for 200s. After changing the operating frequency to 35Hz for 150s, the powder of modified thermally conductive filler 4 is obtained.

[0051] II. Synthesis of Tougheners 1. The preparation method of tackifier H1 includes the following steps: (1) Add 50g of hydrogen-containing silicone oil with a hydrogen content of 1.2% to a 500mL three-necked flask equipped with a thermometer, and then add 3ppm of Castel platinum catalyst; stir to mix the raw materials evenly; then add 45.6g of allyl glycidyl ether, with a Si-H to vinyl molar ratio of 1.5:1, while stirring. After the addition is complete, immediately raise the temperature to 80℃ and stir the reaction for 2h. (2) After purging with nitrogen, add 31g of vinyltrimethoxysilane to the reaction flask. The molar ratio of vinyl to residual Si-H is 1.05 to ensure that Si-H is completely reacted. The reaction time is 6h. (3) After the reaction is complete, a light yellow semi-transparent liquid is obtained. Then, it is poured into a Buchner funnel containing activated carbon for filtration. The filtered liquid is then poured into the Buchner funnel for filtration again. This process is repeated at least 5 times to remove residual platinum from the system and obtain thickener H1.

[0052] 2. The preparation method of tackifier H2 includes the following steps: (1) Add 50g of hydrogen-containing silicone oil with a hydrogen content of 1.5% to a 500mL three-necked flask equipped with a thermometer, and then add 3ppm of Castel platinum catalyst; stir to mix the raw materials evenly; then add 42.75g of allyl glycidyl ether, with a Si-H to vinyl molar ratio of 2:1, while stirring. After the addition is complete, immediately raise the temperature to 80℃ and react for 4h. (2) After purging with nitrogen, add 58.27 g of vinyltrimethoxysilane to the reaction flask. The molar ratio of vinyl to residual Si-H is 1.05, and the reaction time is 8 h. (3) After the reaction is complete, a light yellow semi-transparent liquid is obtained. Then, it is poured into a Buchner funnel containing activated carbon for filtration. The filtered liquid is then poured into the Buchner funnel for filtration again. This process is repeated at least 5 times to obtain thickener H2.

[0053] 3. The preparation method of tackifier H3 includes the following steps: (1) Add 50g of hydrogen-containing silicone oil with a hydrogen content of 1.5% to a 500mL three-necked flask equipped with a thermometer, and then add 3ppm of Castel platinum catalyst; stir to mix the raw materials evenly; then add 42.75g of allyl glycidyl ether, with a Si-H to vinyl molar ratio of 2:1, while stirring. After the addition is complete, immediately raise the temperature to 100℃ and react for 4h. (2) After purging with nitrogen, add 51.97 g of methyl vinyl dimethoxysilane to the reaction flask. The molar ratio of vinyl to residual Si-H is 1.05. The reaction time is 8 h. (3) After the reaction is complete, a light yellow semi-transparent liquid is obtained. Then, it is poured into a Buchner funnel containing activated carbon for filtration. The filtered liquid is then poured into the Buchner funnel for filtration again. This process is repeated at least 5 times to obtain thickener H3.

[0054] Example 2 In this embodiment, a waterproof and thermally conductive adhesive potting compound includes component A and component B. Component A comprises the following raw materials in parts by weight: 29 parts vinyl-terminated polydimethylsiloxane, 13 parts polymethylhydrosiloxane, 75 parts thermally conductive filler, 0.02 parts carbon black paste, 0.005 parts inhibitor, and 0.6 parts tackifier. The polymethylhydrosiloxane has a hydrogen content of 0.18%, and the tackifier is tackifier H1 prepared in the embodiment. The inhibitor is methylbutyninol. Component B comprises the following raw materials in parts by weight: 42 parts vinyl-terminated polydimethylsiloxane, 75 parts thermally conductive filler, and 0.3 parts catalyst.

[0055] Furthermore, the thermally conductive fillers in both component A and component B are modified thermally conductive fillers, specifically the modified thermally conductive filler 1 prepared in Example 1.

[0056] In this embodiment, the preparation method of the above-mentioned waterproof and thermally conductive adhesive potting compound includes the following steps: Preparation of Component A: By weight, 23 parts of vinyl-terminated polydimethylsiloxane with a viscosity of 100 cps and 75 parts of modified thermally conductive filler 1 were added to a kneader. The mixture was heated to 180℃, with a vacuum degree of <-0.08 MPa and a stirring speed of 30 Hz, and stirred for 2 hours. After the material cooled to room temperature, it was transferred to a dual planetary mixer. Then, 6 parts of vinyl-terminated polydimethylsiloxane with a viscosity of 500 cps, 13 parts of polymethylhydrosiloxane, 0.005 parts of inhibitor, 0.02 parts of carbon black paste, and 0.6 parts of thickener H1 were added. The mixture was stirred under vacuum for 40 minutes, with a vacuum degree of <-0.08 MPa and a stirring speed of 400 r / min, to obtain Component A. Preparation of Component B: 23 parts of vinyl-terminated polydimethylsiloxane with a viscosity of 100 cps and 75 parts of modified thermally conductive filler 1 were added to a kneader. The mixture was heated to 180℃, with a vacuum degree < -0.08 MPa and a stirring speed of 30 Hz for 2 hours. After the material cooled to room temperature, it was transferred to a dual planetary mixer. Then, 19 parts of vinyl-terminated polydimethylsiloxane with a viscosity of 100 cps and 0.3 parts of Castel platinum catalyst with a concentration of 5000 ppm were added. The mixture was stirred under vacuum for 40 minutes, with a vacuum degree < -0.08 MPa and a stirring speed of 400 r / min, to obtain Component B. By designing the specific steps, raw material types, and dosages for the preparation of the waterproof and thermally conductive adhesive potting compound, a high-performance waterproof and thermally conductive adhesive potting compound was obtained.

[0057] Example 3 In this embodiment, a waterproof and thermally conductive adhesive potting compound includes component A and component B. Component A comprises the following raw materials in parts by weight: 29 parts vinyl-terminated polydimethylsiloxane, 13 parts polymethylhydrosiloxane, 75 parts thermally conductive filler, 0.02 parts carbon black paste, 0.005 parts inhibitor, and 0.8 parts tackifier. The tackifier is tackifier H2 prepared in the embodiment; the inhibitor is methylbutynol. Component B comprises the following raw materials in parts by weight: 42 parts vinyl-terminated polydimethylsiloxane, 75 parts thermally conductive filler, and 0.3 parts catalyst.

[0058] Furthermore, the thermally conductive fillers in both component A and component B are modified thermally conductive fillers, specifically the modified thermally conductive filler 2 prepared in Example 1.

[0059] In this embodiment, the preparation method of the above-mentioned waterproof and thermally conductive adhesive potting compound includes the following steps: Preparation of Component A: By weight, 23 parts of vinyl-terminated polydimethylsiloxane with a viscosity of 100 cps and 75 parts of modified thermally conductive filler 2 were added to a kneader. The mixture was heated to 180℃, with a vacuum degree of <-0.08 MPa and a stirring speed of 30 Hz, and stirred for 2 hours. After the material cooled to room temperature, it was transferred to a dual planetary mixer. Then, 6 parts of vinyl-terminated polydimethylsiloxane with a viscosity of 500 cps, 13 parts of polymethylhydrosiloxane, 0.005 parts of inhibitor, 0.02 parts of carbon black paste, and 0.8 parts of thickener H2 were added. The mixture was stirred under vacuum for 60 minutes, with a vacuum degree of <-0.08 MPa and a stirring speed of 300 r / min, to obtain Component A. Preparation of Component B: 23 parts of vinyl-terminated polydimethylsiloxane with a viscosity of 100 cps and 75 parts of modified thermally conductive filler 2 were added to a kneader. The temperature was raised to 180℃, the vacuum degree was <-0.08MPa, the stirring speed was 30Hz, and the reaction was carried out for 2 hours. After the material cooled to room temperature, it was transferred to a double planetary mixer. Then, 19 parts of vinyl-terminated polydimethylsiloxane with a viscosity of 100 cps and 0.3 parts of Castel platinum catalyst with a concentration of 5000ppm were added. The mixture was stirred under vacuum for 60 minutes, the vacuum degree was <-0.08MPa, and the stirring speed was 300r / min to obtain Component B.

[0060] Example 4 In this embodiment, a waterproof and thermally conductive adhesive potting compound includes component A and component B. Component A comprises the following raw materials in parts by weight: 29 parts vinyl-terminated polydimethylsiloxane, 13 parts polymethylhydrosiloxane, 75 parts thermally conductive filler, 0.02 parts carbon black paste, 0.005 parts inhibitor, and 1 part tackifier. The tackifier is tackifier H3 obtained in the embodiment; the inhibitor is methylbutynol. Component B comprises the following raw materials in parts by weight: 42 parts vinyl-terminated polydimethylsiloxane, 75 parts thermally conductive filler, and 0.3 parts catalyst.

[0061] Furthermore, the thermally conductive fillers in both component A and component B are modified thermally conductive fillers, specifically the modified thermally conductive filler 1 prepared in Example 1.

[0062] In this embodiment, the preparation method of the above-mentioned waterproof and thermally conductive adhesive potting compound includes the following steps: Preparation of Component A: By weight, 23 parts of vinyl-terminated polydimethylsiloxane with a viscosity of 100 cps and 75 parts of modified thermally conductive filler 1 were added to a kneader. The mixture was heated to 180℃, with a vacuum degree of <-0.08 MPa and a stirring speed of 30 Hz, and stirred for 2 hours. After the material cooled to room temperature, it was transferred to a double planetary mixer. Then, 6 parts of vinyl-terminated polydimethylsiloxane with a viscosity of 500 cps, 13 parts of polymethylhydrosiloxane, 0.005 parts of inhibitor, 0.02 parts of carbon black paste, and 1 part of thickener H3 were added. The mixture was stirred under vacuum for 60 minutes, with a vacuum degree of <-0.08 MPa and a stirring speed of 300 r / min, to obtain Component A. Preparation of Component B: 23 parts of vinyl-terminated polydimethylsiloxane with a viscosity of 100 cps and 75 parts of modified thermally conductive filler 1 were added to a kneader. The temperature was raised to 180℃, the vacuum degree was <-0.08MPa, the stirring speed was 30Hz, and the reaction was carried out for 2 hours. After the material cooled to room temperature, it was transferred to a double planetary power mixer. Then, 19 parts of vinyl-terminated polydimethylsiloxane with a viscosity of 100 cps and 0.3 parts of Castel platinum catalyst with a concentration of 5000ppm were added. The mixture was stirred under vacuum for 60 minutes, the vacuum degree was <-0.08MPa, and the stirring speed was 300r / min to obtain Component B.

[0063] Example 5 In this embodiment, a waterproof and thermally conductive adhesive potting compound includes component A and component B. Component A comprises the following raw materials in parts by weight: 29 parts vinyl-terminated polydimethylsiloxane, 10 parts polymethylhydrosiloxane, 75 parts thermally conductive filler, 0.02 parts carbon black paste, 0.005 parts inhibitor, and 1 part tackifier. The tackifier is tackifier H1 prepared in the embodiment; the inhibitor is ethynylcyclohexanol. Component B comprises the following raw materials in parts by weight: 41 parts vinyl-terminated polydimethylsiloxane, 75 parts thermally conductive filler, and 0.3 parts catalyst.

[0064] Furthermore, the thermally conductive fillers in both component A and component B are modified thermally conductive fillers, specifically the modified thermally conductive filler 1 prepared in Example 1.

[0065] In this embodiment, the preparation method of the above-mentioned waterproof and thermally conductive adhesive potting compound includes the following steps: Preparation of Component A: By weight, 23 parts of vinyl-terminated polydimethylsiloxane with a viscosity of 100 cps and 75 parts of modified thermally conductive filler 1 were added to a kneader. The mixture was heated to 180℃, with a vacuum degree of <-0.08 MPa and a stirring speed of 30 Hz, and stirred for 2 hours. After the material cooled to room temperature, it was transferred to a dual planetary mixer. Then, 6 parts of vinyl-terminated polydimethylsiloxane with a viscosity of 300 cps, 10 parts of polymethylhydrosiloxane, 0.005 parts of inhibitor, 0.02 parts of carbon black paste, and 1 part of thickener H1 were added. The mixture was stirred under vacuum for 60 minutes, with a vacuum degree of <-0.08 MPa and a stirring speed of 300 r / min, to obtain Component A. Preparation of Component B: 23 parts of vinyl-terminated polydimethylsiloxane with a viscosity of 300 cps and 75 parts of modified thermally conductive filler 1 were added to a kneader. The temperature was raised to 180℃, the vacuum degree was <-0.08MPa, the stirring speed was 30Hz, and the reaction was carried out for 2 hours. After the material cooled to room temperature, it was transferred to a double planetary mixer. Then, 18 parts of vinyl-terminated polydimethylsiloxane with a viscosity of 230 cps and 0.3 parts of Castel platinum catalyst with a concentration of 5000ppm were added. The mixture was stirred under vacuum for 60 minutes, the vacuum degree was <-0.08MPa, and the stirring speed was 300r / min to obtain Component B.

[0066] The remaining unmentioned aspects of Examples 3-5 are the same as those in Example 1.

[0067] Comparative Example 1 The difference between this comparative example and Example 2 is that in this comparative example, when preparing component A of the waterproof and thermally conductive adhesive potting compound, an equal amount of modified thermally conductive filler 3 is used to replace the modified thermally conductive filler 1 in Example 2. The rest of the contents not mentioned are the same as in Example 2.

[0068] Comparative Example 2 The difference between this comparative example and Example 2 is that in this comparative example, when preparing component A of the waterproof and thermally conductive adhesive potting compound, an equal amount of modified thermally conductive filler 4 is used to replace the modified thermally conductive filler 1 in Example 2. The rest of the contents not mentioned are the same as in Example 2.

[0069] Comparative Example 3 The difference between this comparative example and Example 3 is that in this comparative example, when preparing component A of the waterproof and thermally conductive adhesive potting compound, an equal amount of silane coupling agent KH-560 is used as a tackifier to replace tackifier H2 in Example 3. The rest of the contents not mentioned are the same as in Example 3.

[0070] Comparative Example 4 The difference between this comparative example and Example 4 is that in this comparative example, when preparing component A of the waterproof and thermally conductive adhesive potting compound, an equal amount of modified thermally conductive filler 4 is used to replace modified thermally conductive filler 1 in Example 4, and an equal amount of silane coupling agent KH-570 is used to replace tackifier H3 in Example 4. The rest of the contents not mentioned are the same as in Example 4.

[0071] Comparative Example 5 The difference between this comparative example and Example 4 is that in this comparative example, when preparing component A of the waterproof and thermally conductive adhesive potting compound, an equal amount of modified thermally conductive filler 4 is used to replace the modified thermally conductive filler 1 in Example 4, and no tackifier is added. The rest of the contents are the same as in Example 4.

[0072] The performance of the two-component potting compounds of Examples 2-5 and Comparative Examples 1-5 of the present invention was tested through the following experiments. The test results are shown in Table 1 below: 1. Viscosity test Components A and B obtained from the examples and comparative examples were tested according to standard GB / T 2794-2013.

[0073] 2. Adhesion performance test After mixing components A and B in a 1:1 mass ratio, the adhesive performance of the adhesive to Al and PCB was tested at room temperature according to the test method of GB / T7124-2008.

[0074] 3. Water vapor transmission rate test Water vapor transmission rate was tested according to GB / T 1073-2021.

[0075] Table 1 Performance test results of two-component potting compound As can be seen from the table: (1) In Examples 2-5, a self-made tackifier was added to component A. Compared with Comparative Examples 3-5, this shows that the self-made tackifier can significantly improve the bonding effect of the potting compound to Al and PCBA boards; (2) In Examples 2-5 and Comparative Example 3, vinylphenyl silane was used as a powder modifier for the thermally conductive filler. Compared with the use of ordinary modifiers in Comparative Examples 1, 2, 4, and 5, the water vapor permeability of the silicone was greatly reduced. This shows that by introducing phenyl into the siloxane backbone, the low polarity and steric hindrance effect of phenyl also effectively hindered the penetration of water molecules into the silicone backbone, thus achieving a waterproof effect.

[0076] The specific embodiments described above are further illustrations of the technical solution and beneficial effects of the present invention, and are not intended to limit the implementation methods. For those skilled in the art, any obvious substitutions without departing from the concept of the present invention are within the protection scope of the present invention.

Claims

1. A waterproof, heat-conducting, adhesive potting adhesive, characterized by: It comprises A component and B component, the A component comprises vinyl polydimethylsiloxane, polymethyl hydrogen siloxane, heat-conducting filler, color paste, inhibitor and tackifier; the B component comprises vinyl polydimethylsiloxane, heat-conducting filler and catalyst.

2. The waterproof, heat-conductive adhesive potting compound of claim 1, wherein: It comprises A component and B component; the A component comprises the following raw materials by weight: vinyl polydimethylsiloxane 20-30 parts, polymethyl hydrogen siloxane 5-20 parts, heat-conducting filler 65-80 parts, color paste 0.01-1 part, inhibitor 0.001-0.1 part, tackifier 0.5-2 parts; The B component comprises the following raw materials by weight: vinyl polydimethylsiloxane 35-45 parts, heat-conducting filler 65-80 parts, catalyst 0.1-0.5 parts.

3. The waterproof, heat-conductive adhesive potting compound of claim 1, wherein: The vinyl polydimethylsiloxane in the A component and the B component is vinyl-terminated polydimethylsiloxane, and the viscosity is 50-500 cps.

4. The waterproof, heat-conductive adhesive potting compound of claim 1, wherein: The polymethyl hydrogen siloxane in the A component is composed of one or more polymethyl hydrogen siloxanes with a hydrogen content of 0.05-1.0%.

5. The waterproof, heat-conductive adhesive potting compound of claim 1, wherein: The heat-conducting filler in the A component and the B component is a modified heat-conducting filler, which is composed of an initial heat-conducting filler and treated by a modifier, and the initial heat-conducting filler is at least one of aluminum oxide, silicon powder, aluminum hydroxide, calcium carbonate and zinc oxide.

6. The waterproof, heat-conductive adhesive potting compound of claim 5, wherein: The modifier is at least one of trimethoxy (4-vinylphenyl) silane, vinylphenyldiethoxysilane, [2-[3(or 4)-vinylphenyl]ethyl]trimethoxysilane and triethoxy (1-phenylvinyl) silane.

7. The waterproof, thermally-conductive, adhesive potting compound of claim 1, wherein: The inhibitor in the A component is at least one of ethynylcyclohexanol, methylbutynol and methylvinylcyclosiloxane.

8. The waterproof, thermally-conductive, adhesive potting compound of claim 1, wherein: The tackifier in the A component contains multiple epoxy groups and multiple alkoxy groups in its structure.

9. The waterproof, thermally-conductive, adhesive potting compound of claim 1, wherein: The catalyst in the B component is a platinum-gold catalyst.

10. A method for preparing the waterproof heat-conducting adhesive sealant according to any one of claims 1-9, characterized in that: It comprises the following steps: Preparation of the A component: first, uniformly stir part of the vinyl polydimethylsiloxane and the heat-conducting filler under heating and vacuum conditions; after the material cools to room temperature, add the remaining vinyl polydimethylsiloxane, and add the polymethyl hydrogen siloxane, inhibitor, color paste and tackifier, and uniformly stir under vacuum conditions to obtain the A component; Preparation of the B component: first, uniformly stir the vinyl polydimethylsiloxane and the heat-conducting filler under heating and vacuum conditions; after the material cools to room temperature, add the remaining vinyl polydimethylsiloxane and the catalyst, and uniformly stir under vacuum conditions to obtain the B component.

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