Low-viscosity high-thermal-conductivity organic silicon bonding pouring sealant and preparation method thereof

Abstract

The invention provides a low-viscosity high-thermal-conductivity organic silicon bonding pouring sealant and a preparation method thereof, the organic silicon bonding pouring sealant comprises a component A and a component B, the component A is prepared from a basic silica gel polymer, a thermal conductive filler, an anti-settling agent, a cross-linking agent and a tackifier M, and the component B is prepared from a basic silica gel polymer, a thermal conductive filler, an anti-settling agent, a catalyst, an inhibitor and a tackifier N; the tackifier M has at least two alkoxy groups, and the tackifier N is silylated maleic anhydride. The two tackifiers are matched, the heat conductivity coefficient of the prepared high-heat-conductivity pouring sealant is 2.0 W / (m.k) or above, and the prepared high-heat-conductivity pouring sealant is low in viscosity, so that the prepared high-heat-conductivity pouring sealant is good in flowability and has a very good bonding effect on base materials such as Al, PVC, PMMA and a PCB.

Description

Technical Field

[0001] The invention belongs to the technical field of silicone rubber and adhesive, and specifically relates to a low-viscosity, high-thermal-conductivity organic silicon bonding potting adhesive and a preparation method thereof. Background Art

[0002] As the concentration of electronic components increases and the power density continues to increase, the heat management of electronic components has become a key issue, restricting the long-term, safe and stable operation of electronic components. Adhesive materials with high thermal conductivity can quickly transfer heat, reduce the temperature of components, and prevent the life of components from being attenuated due to overheating. At the same time, adhesive materials need to have good fluidity so that they can be filled into components with complex structures, including tiny gaps and corners, during the packaging process. Low-viscosity adhesive materials make it easier to achieve this, as they can reduce the formation of bubbles and ensure the consistency and integrity of the package.

[0003] Silicone adhesive materials are widely used because of their chemical and thermal stability and good electrical insulation properties. They can maintain stable performance in very harsh environments, which is crucial for the long-term reliability of electronic equipment. This material is not only used to transfer heat in the field of electronics and electrical engineering, but is also often used to provide waterproof sealing properties. This requires silicone adhesive materials to have not only excellent thermal conductivity, but also good adhesion and flow properties, and to form a continuous, weather-resistant barrier between electronic components and circuit boards, thereby protecting internal components from moisture, humidity and chemical corrosion. However, addition-type thermal conductive potting glue has poor adhesion and requires a large amount of tackifiers to achieve effective bonding. However, adding highly active tackifiers will affect the viscosity and flowability of the glue, and adding less active tackifiers will not achieve room temperature bonding.

[0004] Chinese patent document with publication number CN105038694A provides a method for preparing an adhesive potting glue, which needs to be baked at a temperature greater than 100°C for more than 30 minutes to achieve an effective bonding effect. However, many electronic components cannot withstand high-temperature baking, which limits its use; Chinese patent document with publication number CN106221666A provides a method for preparing a high thermal conductivity and high bonding strength potting glue, but its thermal conductivity is low at only 1.5W / (mk), and it is unable to quickly dissipate the heat of electronic components, resulting in heat accumulation and temperature rise, affecting the safe and stable operation of components. Summary of the invention

[0005] In view of the defects of the prior art, the present invention provides a low-viscosity and high-thermal-conductive silicone adhesive potting glue and a preparation method thereof, in the hope of solving the problem that it is difficult to balance the adhesion, fluidity and room-temperature adhesion of the addition-type thermal conductive potting glue.

[0006] In order to solve the above technical problems, the first aspect of the present invention provides a low-viscosity and high-thermal-conductivity silicone adhesive potting glue, which is a two-component glue, including component A and component B, component A is made of a basic silicone polymer, a thermally conductive filler, an anti-settling agent, a cross-linking agent and a tackifier M, and component B is made of a basic silicone polymer, a thermally conductive filler, an anti-settling agent, a catalyst, an inhibitor and a tackifier N; the tackifier M has at least two alkoxy groups, and the tackifier N is silylated maleic anhydride.

[0007] Optionally, the low-viscosity and high-thermal-conductivity silicone adhesive potting adhesive is made of raw materials including the following components, measured by weight:

[0008] Component A

[0009]

[0010]

[0011] Component B

[0012]

[0013] Preferably, the low-viscosity, high-thermal-conductivity silicone adhesive potting adhesive is made of raw materials including the following components, measured in parts by mass:

[0014] Component A

[0015]

[0016] Component B

[0017]

[0018] A further technical solution is that the tackifier M described in component A is a compound of one or more of 1,2-bis(ethoxysilyl)ethane, 1,6-bistrimethoxysilylhexane, bisethoxysilylmethane, 1,2-bis(trimethoxysilyl)decane, tetraethyl orthosilicate, and tetrapropoxysilane; preferably, the tackifier M is 1,2-bis(ethoxysilyl)ethane, bisethoxysilylmethane, or 1,2-bis(trimethoxysilyl)decane. The tackifier M has at least two alkoxy groups.

[0019] A further technical solution is that the tackifier N described in component B is silylated maleic anhydride, and its structural formula is as follows:

[0020]

[0021] Among them, the structural formula of R is -(CH2) n CH3, n is a natural number ranging from 0 to 12.

[0022] Optionally, the preparation method of tackifier N is as follows:

[0023] (1) In a 500 ml three-necked flask equipped with a thermometer, 0.1-0.3 mol of maleic anhydride, 0.15 g of a Custer platinum catalyst having a platinum concentration of 3000 ppm, and 100 ml of a toluene solvent were added, the temperature was raised to 60° C., and the mixture was stirred for 40 min to obtain a maleic anhydride toluene solution;

[0024] (2) cooling the maleic anhydride toluene solution to room temperature, adding 0.11-0.33 mol of trialkylsilane dropwise into the flask, stirring and reacting for 30-120 min in a nitrogen atmosphere to obtain a silylated maleic anhydride mixed solution;

[0025] (3) pouring the silylated maleic anhydride mixture into a conical flask filled with activated carbon, shaking it and letting it stand for 24 hours, and filtering to remove the residual platinum catalyst;

[0026] (4) The filtered solution was distilled under reduced pressure at 50°C to remove the toluene solvent to obtain silylated maleic anhydride.

[0027] Optionally, the basic silicone polymer of component A and component B is vinyl-terminated polydimethylsiloxane with a viscosity of 50 to 1000 cps; preferably, the viscosity of the vinyl-terminated polydimethylsiloxane is 50 to 300 cps. Unless otherwise stated, the viscosity described in the present invention is the viscosity tested at 25°C. The basic silicone polymers used in component A and component B can be the same or different.

[0028] Optionally, the anti-settling agent described in component A and component B is selected from one or more of fumed silica, carbon black, submicron alumina, hollow glass microspheres, nano calcium carbonate, and zinc oxide. Preferably, the anti-settling agent is submicron alumina or zinc oxide. The submicron alumina refers to alumina with a crystal particle size of less than 1 micron obtained by micron processing technology. The anti-settling agents used in component A and component B can be the same or different.

[0029] Optionally, the thermal conductive fillers described in component A and component B are both compounded with alumina of different particle sizes and morphologies, the particle size of alumina is distributed in the range of 1 to 70um, the morphology of alumina can be spherical or irregular, and the preferred alumina particle size is any of 2um, 5um, 10um, 20um, 40um, and 70um. The compounding can be done in equal mass proportions or in unequal mass proportions, and the morphology is spherical. The thermal conductive fillers used in component A and component B can be the same or different.

[0030] Optionally, the crosslinking agent in component A is polymethylhydrogensiloxane, which is composed of one or more polymethylhydrogensiloxanes with a hydrogen content of 0.1 to 1.2%, and preferably the hydrogen content of the polymethylhydrogensiloxane is 0.1 to 0.5%.

[0031] Optionally, the catalyst of component B is a Speier catalyst or a Custer catalyst, and preferably the catalyst is a Custer platinum catalyst.

[0032] Optionally, the inhibitor in component B is one or more of ethynyl cyclohexanol, methyl butynol, and methyl vinyl cyclosiloxane, and preferably the inhibitor is methyl butynol or ethynyl cyclohexanol.

[0033] Optionally, component B also uses a pigment, with 0.01 to 0.2 parts of the pigment used for every 5 to 20 parts of the basic silicone polymer.

[0034] The second aspect of the present invention provides a method for preparing a low-viscosity and high-thermal-conductivity organic silicon adhesive potting glue, comprising the following steps:

[0035] Component A: First, stir the basic silicone polymer and thermal conductive filler evenly under vacuum, then add the cross-linking agent and anti-settling agent and stir evenly under vacuum, and finally add the tackifier M and stir evenly under vacuum to obtain component A;

[0036] Component B: First, stir the basic silicone polymer, thermal conductive filler, anti-settling agent (and pigment, if any) under vacuum, then add the catalyst and inhibitor and stir them under vacuum, finally add the tackifier N and stir them under vacuum to obtain component B.

[0037] Furthermore, in the preparation method of the low-viscosity and high-thermal-conductivity silicone adhesive potting glue, the stirring equipment can select a double planetary power mixing mixer, the vacuum degree is set to less than -0.06MPa, and the stirring speed is 300-600r / min; for component A or component B, the first two stirrings can be stirred at a stirring speed of 300-600r / min for 30-120min, and the vacuum degree is set to less than -0.06MPa. The last stirring can be stirred at a stirring speed of 300-600r / min for 10-30min, and the vacuum degree is set to less than -0.08MPa.

[0038] Based on the above-mentioned method for preparing the low-viscosity and high-thermal-conductivity organic silicon adhesive potting glue, the following operation steps can be used to realize the production of the low-viscosity and high-thermal-conductivity organic silicon adhesive potting glue of the present invention:

[0039] Add basic silicone polymer and thermal conductive filler to a dual planetary power mixer, maintain vacuum stirring for 30 to 120 minutes, vacuum degree <-0.06MPa, stirring speed 300 to 600r / min; then add crosslinking agent and anti-settling agent, maintain vacuum stirring for 30 to 120 minutes, vacuum degree <-0.06MPa, stirring speed 300 to 600r / min; then add viscosity enhancer M, vacuum stirring, stirring speed 300 to 600r / min, vacuum degree <-0.08MPa, stirring for 10 to 30 minutes, discharging, and obtaining component A;

[0040] Add basic silicone polymer, thermal conductive filler, anti-settling agent and pigment into a dual planetary power mixer, stir under vacuum for 30 to 120 minutes, vacuum degree <-0.06MPa, stirring speed 300 to 600r / min; then add catalyst and inhibitor, stir under vacuum for 30 to 120 minutes, vacuum degree <-0.06MPa, stirring speed 300 to 600r / min; then add viscosity enhancer N, stir under vacuum, stirring speed 300 to 600r / min, vacuum degree <-0.08MPa, stir for 10 to 30 minutes, and obtain component B.

[0041] Compared with the prior art, the present invention has at least the following beneficial effects:

[0042] 1. The present invention designs a low-viscosity and high-thermal-conductivity organic silicon adhesive potting glue. By selecting a polyalkyl structure tackifier (tackifier M), the organic silicon adhesive potting glue can combine with the hydroxyl groups on the surface of the substrate to form more reliable chemical bonds, thereby achieving a better bonding effect;

[0043] 2. The present invention adopts a synergistic tackifier (when using tackifier M, tackifier N is used to promote the tackifying effect), which not only ensures that the glue has good fluidity and stability during long-term storage, but also ensures that the glue has a good bonding effect after curing; the present invention adds a tackifier (tackifier M) with low activity in component A, and tackifier M is not easy to form hydrogen bonds with the surface of the filler powder, and has little effect on the viscosity of component A; the present invention adds silanized maleic anhydride (tackifier N) in component B, which has good compatibility with the glue base polymer, and when components A and B are mixed, silanized maleic anhydride is hydrolyzed into silanized maleic acid, which promotes the hydrolysis of the polysiloxy groups of tackifier M into more silanol groups, so that the silicone bonding potting glue can achieve a good bonding effect even at room temperature, and has good adhesion to several commonly used substrates such as Al, PVC, PMMA, and PCB boards. DETAILED DESCRIPTION

[0044] 1. Synthesis Example of Tackifier N

[0045] Synthesis of tackifier N1:

[0046] 1. Add 0.1 mol of maleic anhydride, 0.15 g of Custer platinum catalyst with a platinum concentration of 3000 ppm, and 100 ml of toluene solvent to a 500 ml three-necked flask equipped with a thermometer, heat to 60°C and stir for 40 min to obtain a maleic anhydride toluene solution; 2. Cool the maleic anhydride toluene solution to room temperature, add 0.11 mol of trimethylsilane dropwise to the flask, stir and react for 30 min under a nitrogen atmosphere to obtain a trimethylsilylmaleic anhydride mixed solution; 3. Pour the mixed solution into a conical flask filled with activated carbon, shake and let stand for 24 hours, and filter to remove the residual platinum catalyst; 4. Distill the filtered solution under reduced pressure at 50°C to remove the toluene solvent to obtain trimethylsilylmaleic anhydride (N1).

[0047] Synthesis of tackifier N2:

[0048] 1. Add 0.1 mol of maleic anhydride, 0.15 g of Custer platinum catalyst with a platinum concentration of 3000 ppm, and 100 ml of toluene solvent to a 500 ml three-necked flask equipped with a thermometer, heat to 60°C and stir for 40 min to obtain a maleic anhydride toluene solution; 2. Cool the maleic anhydride toluene solution to room temperature, add 0.11 mol of tripropylsilane dropwise to the flask, stir and react for 50 min under a nitrogen atmosphere to obtain a tripropylsilylmaleic anhydride mixed solution; 3. Pour the mixed solution into a conical flask filled with activated carbon, shake and let stand for 24 hours, and filter to remove the residual platinum catalyst; 4. Distill the filtered solution under reduced pressure at 50°C to remove the toluene solvent to obtain tripropylsilylmaleic anhydride (N2).

[0049] Synthesis of tackifier N3:

[0050] 1. Add 0.1 mol of maleic anhydride, 0.15 g of Custer platinum catalyst with a platinum concentration of 3000 ppm, and 100 ml of toluene solvent to a 500 ml three-necked flask equipped with a thermometer, heat to 60°C and stir for 40 min to obtain a maleic anhydride toluene solution; 2. Cool the maleic anhydride toluene solution to room temperature, add 0.11 mol of trioctylsilane dropwise to the flask, stir and react for 80 min under a nitrogen atmosphere to obtain a trioctylsilyl maleic anhydride mixed solution; 3. Pour the mixed solution into a conical flask filled with activated carbon, shake and let stand for 24 hours, and filter to remove the residual platinum catalyst; 4. Distill the filtered solution under reduced pressure at 50°C to remove the toluene solvent to obtain trioctylsilyl maleic anhydride (N3).

[0051] Synthesis of tackifier N4:

[0052] 1. Add 0.1 mol of maleic anhydride, 0.15 g of Custer platinum catalyst with a platinum concentration of 3000 ppm, and 100 ml of toluene solvent to a 500 ml three-necked flask equipped with a thermometer, heat to 60°C and stir for 40 min to obtain a maleic anhydride toluene solution; 2. Cool the maleic anhydride toluene solution to room temperature, add 0.11 mol of tri(dodecyl)silane dropwise to the flask, stir and react for 80 min under a nitrogen atmosphere to obtain a tri(dodecyl)silyl maleic anhydride mixed solution; 3. Pour the mixed solution into a conical flask filled with activated carbon, shake and let stand for 24 hours, and filter to remove the residual platinum catalyst; 4. Distill the filtered solution under reduced pressure at 50°C to remove the toluene solvent to obtain tri(dodecyl)silyl maleic anhydride (N4).

[0053] The prepared tackifiers N1 to N4 are all used for the preparation of low-viscosity and high-thermal-conductivity organic silicone bonding and potting adhesives.

[0054] 2. Preparation Example of Low Viscosity and High Thermal Conductivity Silicone Adhesive Potting Glue

[0055] Example 1

[0056] Add 10 parts of 100cps vinyl-terminated polydimethylsiloxane, 40 parts of spherical alumina with a particle size of 40um, 20 parts of spherical alumina with a particle size of 20um, and 30 parts of spherical alumina with a particle size of 5um into a dual planetary power mixer, stir for 30 minutes under vacuum at a stirring speed of 300r / min; then add 4 parts of polymethylhydrogensiloxane with a hydrogen content of 0.18% and 1 part of zinc oxide, stir for 30 minutes under vacuum at a stirring speed of 300r / min; then add 1 part of tackifier 1,2-bis(ethoxysilyl)ethane, stir for 10 minutes under vacuum, and the vacuum degree is <-0.08MPa to obtain component A.

[0057] In a dual planetary power mixer, add 14 parts of 100cps vinyl-terminated polydimethylsiloxane, 40 parts of spherical alumina with a particle size of 40um, 20 parts of spherical alumina with a particle size of 20um, 30 parts of spherical alumina with a particle size of 5um, 1 part of zinc oxide, and 0.1 part of pigment, stir under vacuum for 30 minutes at a stirring speed of 300r / min, then add 0.1 part of Custer platinum catalyst and 0.01 part of methylbutynol, stir under vacuum for 30 minutes at a stirring speed of 300r / min, then add 0.5 part of tackifier N1, stir under vacuum for 10 minutes, and discharge with a vacuum degree of <-0.08MPa to obtain component B.

[0058] Example 2

[0059] Add 10 parts of 100cps vinyl-terminated polydimethylsiloxane, 40 parts of spherical alumina with a particle size of 40um, 20 parts of spherical alumina with a particle size of 10um, and 30 parts of spherical alumina with a particle size of 5um into a dual planetary power mixer, stir under vacuum for 40 minutes at a stirring speed of 500r / min; then add 4 parts of polymethyl hydrogen siloxane with a hydrogen content of 0.18% and 1 part of submicron alumina powder, stir under vacuum for 40 minutes at a stirring speed of 500r / min; then add 1 part of viscosity enhancer 1,2-bis(ethoxysilyl)ethane, stir under vacuum for 20 minutes, and the vacuum degree is <-0.08MPa to obtain component A.

[0060] In a dual planetary power mixer, add 14 parts of 100cps vinyl-terminated polydimethylsiloxane, 40 parts of spherical alumina with a particle size of 40um, 20 parts of spherical alumina with a particle size of 10um, 30 parts of spherical alumina with a particle size of 5um, 1 part of submicron alumina powder, and 0.1 part of pigment. Stir under vacuum for 40 minutes at a stirring speed of 500r / min. Then add 0.1 part of Custer platinum catalyst and 0.01 part of methyl butynol. Stir under vacuum for 40 minutes at a stirring speed of 500r / min. Then add 0.5 part of tackifier N2. Stir under vacuum for 20 minutes and discharge. The vacuum degree is <-0.08MPa to obtain component B.

[0061] Example 3

[0062] Add 10 parts of 100cps vinyl-terminated polydimethylsiloxane, 40 parts of spherical alumina with a particle size of 40um, 30 parts of spherical alumina with a particle size of 20um, and 20 parts of spherical alumina with a particle size of 2um into a dual planetary power mixer, and stir under vacuum for 40 minutes at a stirring speed of 500r / min; then add 4 parts of polymethylhydrogensiloxane with a hydrogen content of 0.18% and 1 part of zinc oxide, and stir under vacuum for 40 minutes at a stirring speed of 500r / min; then add 1 part of tackifier bisethoxysilylmethane, and stir under vacuum for 20 minutes to discharge the material, and the vacuum degree is <-0.08MPa to obtain component A.

[0063] In a dual planetary power mixer, add 14 parts of 100cps vinyl-terminated polydimethylsiloxane, 40 parts of spherical alumina with a particle size of 40um, 30 parts of spherical alumina with a particle size of 20um, 20 parts of spherical alumina with a particle size of 2um, 1 part of zinc oxide, and 0.1 part of pigment. Stir in a vacuum for 40 minutes at a stirring speed of 500r / min. Then add 0.1 part of Custer platinum catalyst and 0.01 part of ethynyl cyclohexanol. Stir in a vacuum for 40 minutes at a stirring speed of 500r / min. Then add 0.5 part of viscosity enhancer N2, stir in a vacuum for 20 minutes, and discharge the material. The vacuum degree is <-0.08MPa to obtain component B.

[0064] Example 4

[0065] Add 10 parts of 300cps vinyl-terminated polydimethylsiloxane, 40 parts of spherical alumina with a particle size of 40um, 30 parts of spherical alumina with a particle size of 10um, and 20 parts of spherical alumina with a particle size of 2um into a dual planetary power mixer, and stir for 60 minutes under vacuum at a stirring speed of 600r / min; then add 2 parts of polymethylhydrogensiloxane with a hydrogen content of 0.18% and 1 part of zinc oxide, and stir for 60 minutes under vacuum at a stirring speed of 600r / min; then add 1 part of tackifier bisethoxysilylmethane, and stir under vacuum for 20 minutes to discharge the material, and the vacuum degree is <-0.08MPa to obtain component A.

[0066] In a dual planetary power mixer, add 14 parts of 300cps vinyl-terminated polydimethylsiloxane, 40 parts of spherical alumina with a particle size of 40um, 30 parts of spherical alumina with a particle size of 10um, 20 parts of spherical alumina with a particle size of 2um, 1 part of zinc oxide, and 0.1 part of pigment, stir under vacuum for 60 minutes at a stirring speed of 600r / min, then add 0.1 part of Custer platinum catalyst and 0.01 part of ethynyl cyclohexanol, stir under vacuum for 60 minutes at a stirring speed of 600r / min, then add 0.5 part of tackifier N3, evacuate and stir for 20 minutes, and the vacuum degree is <-0.08MPa to obtain component B.

[0067] Example 5

[0068] Add 10 parts of 100cps vinyl-terminated polydimethylsiloxane, 30 parts of spherical alumina with a particle size of 40um, 30 parts of spherical alumina with a particle size of 10um, and 30 parts of spherical alumina with a particle size of 2um into a double planetary power mixer, stir under vacuum for 40 minutes at a stirring speed of 500r / min; then add 4 parts of polymethylhydrogensiloxane with a hydrogen content of 0.18% and 1 part of zinc oxide, stir under vacuum for 40 minutes at a stirring speed of 500r / min; then add 1 part of tackifier tetraethyl orthosilicate, vacuum and stir for 20 minutes, and the vacuum degree is <-0.08MPa to obtain component A.

[0069] In a dual planetary power mixer, add 14 parts of 100cps vinyl-terminated polydimethylsiloxane, 30 parts of spherical alumina with a particle size of 40um, 30 parts of spherical alumina with a particle size of 10um, 30 parts of spherical alumina with a particle size of 2um, 1 part of zinc oxide, and 0.1 part of pigment. Stir in a vacuum for 40 minutes at a stirring speed of 500r / min. Then add 0.1 part of Custer platinum catalyst and 0.01 part of ethynyl cyclohexanol. Stir in a vacuum for 40 minutes at a stirring speed of 500r / min. Then add 0.5 part of viscosity enhancer N2, stir in a vacuum for 20 minutes, and discharge with a vacuum degree of <-0.08MPa to obtain component B.

[0070] Example 6

[0071] Add 10 parts of 100cps vinyl-terminated polydimethylsiloxane, 30 parts of spherical alumina with a particle size of 70um, 30 parts of spherical alumina with a particle size of 10um, and 30 parts of spherical alumina with a particle size of 2um into a dual planetary power mixer, stir under vacuum for 40 minutes at a stirring speed of 500r / min; then add 4 parts of polymethylhydrogensiloxane with a hydrogen content of 0.18% and 1 part of submicron alumina powder, stir under vacuum for 40 minutes at a stirring speed of 500r / min; then add 1 part of viscosity enhancer 1,2-bis(ethoxysilyl)ethane, stir under vacuum for 20 minutes, and the vacuum degree is <-0.08MPa to obtain component A.

[0072] In a dual planetary power mixer, add 14 parts of 100cps vinyl-terminated polydimethylsiloxane, 30 parts of spherical alumina with a particle size of 70um, 30 parts of spherical alumina with a particle size of 10um, 30 parts of spherical alumina with a particle size of 2um, 1 part of submicron alumina powder, and 0.1 part of pigment, stir under vacuum for 40 minutes at a stirring speed of 500r / min, then add 0.1 part of Custer platinum catalyst and 0.01 part of methylbutynol, stir under vacuum for 40 minutes at a stirring speed of 500r / min, then add 0.5 part of tackifier N4, stir under vacuum for 20 minutes, and discharge with a vacuum degree of <-0.08MPa to obtain component B.

[0073] Comparative Example 1

[0074] When preparing component B, tackifier N2 was not used, and the other conditions were the same as those in Example 2.

[0075] Comparative Example 2

[0076] When preparing component A, the viscosity enhancer 1,2-bis(ethoxysilyl)ethane was not used, and the other components were the same as those in Example 2.

[0077] Comparative Example 3

[0078] Component A uses tackifier glycidoxypropyltrimethoxysilane instead of tackifier 1,2-bis(ethoxysilyl)ethane, component B does not use tackifier N2, and the rest is the same as in Example 2.

[0079] Comparative Example 4

[0080] Component A uses methacryloyloxytrimethoxysilane as a tackifier instead of 1,2-bis(ethoxysilyl)ethane, and component B does not use tackifier N2. Other aspects are the same as in Example 2.

[0081] Comparative Example 5

[0082] Component A uses tackifier 1,2-bis(methoxysilyl)ethane instead of tackifier 1,2-bis(ethoxysilyl)ethane, component B does not use tackifier N2, and the rest is the same as Example 2.

[0083] Note: When using the potting glue of the embodiment and the comparative example, components A and B are mixed evenly in a mass ratio of 1:1 and cured at room temperature for 24 hours.

[0084] 3. Verification of beneficial effects

[0085] The performance of the two-component potting adhesive of the present invention was tested by the following test, and the results are shown in the table.

[0086] 1. Viscosity test

[0087] The A and B components obtained in the examples and comparative examples were tested according to the standard GB / T 2794-2013.

[0088] 2. Adhesion performance test

[0089] After mixing components A and B in a mass ratio of 1:1, the bonding performance of the glue to Al, PVC, PMMA, and PCB was tested at room temperature according to the GB / T7124-2008 test method.

[0090] 3. Thermal conductivity test method

[0091] After mixing components A and B in a mass ratio of 1:1, the thermal conductivity is tested according to the method specified in ASTM-D5470.

[0092] Table 1 Performance test results of two-component potting glue

[0093]

[0094]

[0095] The A and B components of Examples 1-6 were placed in sealed cans respectively, and after standing for 6 months, the viscosity was tested. The viscosity changes at the initial stage and after storage were compared. The results are shown in Table 2.

[0096] Table 2 Storage stability of two-component potting glue

[0097]

[0098] It can be seen from Table 1 that: (1) if only tackifier M is added to component A and tackifier N is not used in component B (as shown in Comparative Example 1), or if tackifier N is added to component B and tackifier M is not used in component A (as shown in Comparative Example 2), the silicone adhesive potting glue has poor bonding effect at room temperature; (2) if a commercially available conventional tackifier is added to component A (as shown in Comparative Examples 3 to 4), the viscosity of component A of the silicone adhesive potting glue is greatly affected, and tackifier N is not used in component B, and the room temperature bonding performance is poor; although Comparative Example 5 uses tackifier 1,2-bis(methoxysilyl)ethane instead of the combination of tackifier M and tackifier N in other embodiments of the present invention to make the viscosity of components A and B within an acceptable range, the room temperature bonding performance for various substrates is poor; (3) in each embodiment of the present invention, tackifiers are added to component A. Adhesive M, adding N to component B, has a better room temperature bonding effect, mainly because the low-activity tackifier M added to component A is not easy to hydrolyze at room temperature and cannot form hydrogen bonds with the hydroxyl group on the surface of the filler powder. Therefore, it has little effect on the viscosity of component A, ensuring a good flow effect of the glue, which is beneficial to the potting of tiny electronic components; adding silylated maleic anhydride (i.e., tackifier N) to component B has good compatibility with the base polymer. When components A and B are mixed, silylated maleic anhydride is hydrolyzed into silylated maleic acid, which promotes the hydrolysis of polyalkoxy groups in component A to form multiple silicon hydroxyl groups, which can quickly react with the hydroxyl groups on the surface of the substrate to form chemical bonds. Even at room temperature, it can achieve a good bonding effect, prevent water vapor from entering the electronic components, and shorten the service life of the electronic components. This overcomes the problem that conventional tackifiers have a greater impact on the viscosity of the glue and a poor bonding effect.

[0099] It can be seen from Table 2 that in each embodiment of the present invention, tackifier M is added to component A and tackifier N is added to component B. After storage for 6 months, the viscosity of components A and B changes little, indicating that the silicone adhesive potting glue can maintain good fluidity and stability during long-term storage.

[0100] Although the present invention is described herein with reference to the illustrative embodiments of the present invention, it should be understood that those skilled in the art can design many other modifications and implementations, which will fall within the scope and spirit of the principles disclosed in the present application. More specifically, within the scope disclosed in the present application, multiple variations and improvements can be made to the components and / or layout of the subject combination layout. In addition to the variations and improvements made to the components and / or layout, other uses will also be apparent to those skilled in the art.

Claims

1. A low-viscosity and high-thermal-conductivity silicone adhesive potting glue, characterized in that: The invention comprises component A and component B, wherein component A is made of a basic silicone polymer, a thermal conductive filler, an anti-settling agent, a cross-linking agent and a tackifier M, and component B is made of a basic silicone polymer, a thermal conductive filler, an anti-settling agent, a catalyst, an inhibitor and a tackifier N; the tackifier M has at least two alkoxy groups, and the tackifier N is silylated maleic anhydride.

2. The low-viscosity and high-thermal-conductivity organic silicon adhesive potting glue according to claim 1, characterized in that: The tackifier M is a compound of one or more of 1,2-bis(ethoxysilyl)ethane, 1,6-bistrimethoxysilylhexane, bisethoxysilylmethane, 1,2-bis(trimethoxysilyl)decane, tetraethyl orthosilicate, and tetrapropoxysilane.

3. The low-viscosity and high-thermal-conductivity organic silicon adhesive potting glue according to claim 2, characterized in that: The tackifier N has the following structural formula: The structural formula of R is -(CH2) n CH3, n is a natural number ranging from 0 to 12.

4. The low-viscosity and high-thermal-conductivity organic silicon adhesive potting glue according to claim 3, characterized in that: It is prepared from the following raw materials in the following weight ratios: Component A Component B 5. The low-viscosity and high-thermal-conductivity organic silicon adhesive potting glue according to claim 4, characterized in that: It is prepared from the following raw materials in the following weight ratios: Component A Component B 6. The low-viscosity and high-thermal-conductivity organic silicon adhesive potting glue according to claim 4 or 5, characterized in that: The basic silicone polymer described in component A and component B is vinyl-terminated polydimethylsiloxane with a viscosity of 50 to 1000 cps, and the basic silicone polymer described in component A and component B are the same or different; the anti-settling agent described in component A and component B is selected from one or more of fumed silica, carbon black, submicron alumina, hollow glass microspheres, nano calcium carbonate, and zinc oxide, and the anti-settling agent described in component A and component B are the same or different.

7. The low-viscosity and high-thermal-conductivity organic silicon adhesive potting adhesive according to claim 6, characterized in that: The crosslinking agent described in component A is polymethyl hydrogen siloxane, which is composed of one or more polymethyl hydrogen siloxanes with a hydrogen content between 0.1 and 1.2%.

8. The low-viscosity and high-thermal-conductivity organic silicon adhesive potting glue according to claim 6, characterized in that: The catalyst described in component B is a Speier catalyst or a Custer catalyst; the inhibitor described in component B is selected from one or more of ethynyl cyclohexanol, methyl butynol, and methyl vinyl cyclosiloxane.

9. The low-viscosity and high-thermal-conductivity organic silicon adhesive potting adhesive according to claim 6, characterized in that: Component B contains a pigment, and 0.01 to 0.2 parts of the pigment are used for every 5 to 20 parts of the base silicone polymer.

10. The method for preparing the low-viscosity and high-thermal-conductivity organic silicon adhesive potting adhesive according to any one of claims 1 to 9, characterized in that: The following steps are involved: Component A: First, stir the basic silicone polymer and thermal conductive filler evenly under vacuum, then add the cross-linking agent and anti-settling agent and stir evenly under vacuum, and finally add the tackifier M and stir evenly under vacuum to obtain component A; Component B: First, stir the basic silicone polymer, thermal conductive filler, and anti-settling agent evenly under vacuum, then add the catalyst and inhibitor and stir evenly under vacuum, and finally add the tackifier N and stir evenly under vacuum to obtain component B.

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