Preparation method and application of tackifier for silicone thermal conductive potting adhesive

Abstract

The invention discloses a preparation method and application of a tackifier for an organic silicon thermal conductive potting adhesive, and relates to the technical field of potting adhesives using tackifiers and applications thereof. The scheme first uses diphenylsilanediol, trimethylolpropane monoallyl ether and other components as raw materials to prepare a tackifier, and then mixes vinyl silicone oil, the tackifier, hydrogen-containing silicone oil, alkynyl cyclohexanol and other components to prepare the organic silicon potting adhesive. A filler selected from aluminum oxide and aluminum hydroxide is compounded to improve the thermal conductivity and flame retardancy of the organic silicon potting adhesive, and a branched adhesion promoter is used to pretreat the filler to improve the dispersion performance of the filler and the compatibility of the system. The organic silicon potting adhesive finally prepared not only has excellent thermal conductivity and flame retardancy, but also has greatly improved adhesion performance and relatively excellent mechanical properties.

Description

Technical Field

[0001] The present invention relates to the technical field of a tackifier and potting adhesive using the same, in particular to a preparation method and application of a tackifier for organic silicon thermal conductive potting adhesive. Background Art

[0002] Silicone potting compound has good high and low temperature resistance, weather resistance, electrical insulation, and chemical resistance, and is one of the adhesives that has received widespread attention today. However, as electronic components develop towards high-end, refined, and intelligent directions, companies have continuously increased their requirements for the bonding strength, mechanical strength, and other properties of silicone potting compounds. Therefore, which tackifiers to use to increase the viscosity of silicone potting compounds and how to improve the mechanical properties of silicone potting compounds have become important topics for R&D personnel.

[0003] Patent CN201210421580.2 discloses a method for preparing a tackifier for addition-type silicone potting glue. This patent uses raw materials such as hydroxy acrylate, glycidyl ether alkoxysilane, and titanate to react to prepare a new tackifier. After adding the synthesized tackifier to the silicone potting glue, the bonding performance, water resistance, and thermal conductivity of the potting glue are all improved. Patent CN201811193114.7 discloses the preparation and application of a tackifier for addition-type silicone thermal conductive potting glue. This patent introduces vinyl groups and aniline groups into the tackifier structure. The vinyl groups participate in the reaction of the addition-type silicone thermal conductive potting glue, and the potting glue and the tackifier are bonded together by chemical bond reaction. The introduction of active groups greatly improves the bonding performance of the potting glue. However, the processing cost of the tackifiers disclosed in the above two schemes is relatively high, and the tackifying effect of the prepared tackifiers still cannot meet the actual application requirements.

[0004] Meanwhile, patent CN202411120893.3, a low-viscosity, high-thermal-conductivity silicone adhesive potting compound and its preparation method, utilizes two tackifiers to create a thermally conductive potting compound with high thermal conductivity and excellent bonding to substrates such as aluminum, PVC, PMMA, and PCBs. However, this solution lacks optimized modification of the thermally conductive filler, which easily agglomerates and affects the potting compound's overall bonding performance.

[0005] Based on the above situation, the present application discloses a preparation method and application of a tackifier for silicone thermal conductive potting adhesive, modifies the tackifier, and improves the bonding performance and mechanical properties of the silicone potting adhesive. Summary of the Invention

[0006] The purpose of the present invention is to provide a preparation method and application of a tackifier for silicone thermally conductive potting adhesive, so as to solve the problems raised in the above background technology.

[0007] In order to solve the above technical problems, the present invention provides the following technical solution: a method for preparing a tackifier for silicone thermally conductive potting adhesive, comprising the following steps:

[0008] Step 1: 3-glycidyloxypropyldimethoxymethylsilane, diphenylsilanediol and barium hydroxide were mixed and stirred evenly. The mixture was heated to 80°C to 85°C under a nitrogen atmosphere and reacted for 3h to 5h. Trimethylolpropane monoallyl ether was added and the mixture was reacted at 80°C to 90°C for 3h to 5h. The mixture was purified and separated, and vacuum dried at 60°C to 70°C to obtain a linear adhesion promoter.

[0009] 3-glycidoxypropyltrimethoxysilane, diphenylsilanediol and barium hydroxide were mixed and stirred uniformly, and the mixture was heated to 80-85°C under a nitrogen atmosphere and reacted for 3-5 hours. Trimethylolpropane monoallyl ether was added and the mixture was reacted at 80-90°C for another 3-5 hours. The mixture was purified and separated, and vacuum dried at 60-70°C to obtain a branched adhesion promoter.

[0010] Step 2: Compounding and mixing the linear adhesion promoter and the branched adhesion promoter to obtain the potting adhesive tackifier.

[0011] More optimally, when the linear adhesion promoter is prepared, the molar ratio of 3-glycidyloxypropyldimethoxymethylsilane, diphenylsilanediol, and trimethylolpropane monoallyl ether is 1:1:1.

[0012] More optimally, when preparing the branched adhesion promoter, the molar ratio of 3-glycidyloxypropyltrimethoxysilane, diphenylsilanediol, and trimethylolpropane monoallyl ether is 1:1.5:1.5.

[0013] Optimally, in step 1, the amount of barium hydroxide used is 2% to 3% of the total molar amount of the reaction monomers in the system; in step 2, the mass ratio of the linear adhesion promoter to the branched adhesion promoter is (3 to 4):1.

[0014] More optimally, the tackifier is prepared according to any one of the above methods for preparing a tackifier for silicone thermally conductive potting adhesive.

[0015] More optimally, an application of a tackifier for silicone thermally conductive potting adhesive is provided, wherein the tackifier is applied to the silicone potting adhesive, and the specific steps are as follows: Step A: mixing a filler and ethanol, adding a branched adhesion promoter, reacting at 80°C to 85°C for 3h to 4h, centrifuging at 9000r / min to 10000r / min for 5min to 6min, washing, and vacuum drying to obtain a pretreated filler; the filler is a composite of any one or more of aluminum oxide, aluminum hydroxide, and zinc oxide;

[0016] Step B: Mix the vinyl silicone oil and the pretreated filler, add the above-mentioned tackifier, stir for 5 minutes to 10 minutes, vacuum degassing for 15 minutes to 20 minutes, let it stand for 2 hours to 3 hours, then add hydrogenated silicone oil, alkynyl cyclohexanol and Custer catalyst, mix evenly, and vacuum degassing for 15 minutes to 20 minutes to obtain the silicone thermal conductive potting compound.

[0017] More optimally, in step B, the amounts of each component used are as follows: in parts by mass, 100 parts of vinyl silicone oil, 160-180 parts of pretreated filler, 2-3 parts of tackifier, 7-8 parts of hydrogenated silicone oil, 0.01-0.02 parts of alkynyl cyclohexanol, and 0.3-0.4 parts of Custer catalyst.

[0018] Optimally, in step A, the filler is a composite of aluminum oxide and aluminum hydroxide, with the mass ratio of aluminum oxide to aluminum hydroxide being 4:1. The mass ratio of the filler to the branched adhesion promoter is 1:6. The particle size of the aluminum oxide is 4-5 μm, and the particle size of the aluminum hydroxide is 2-3 μm.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] The invention discloses a tackifier for a silicone thermally conductive potting compound. The method first uses diphenylsilanediol, trimethylolpropane monoallyl ether and other components as raw materials for reaction to prepare the tackifier. When 3-glycidyloxypropyldimethoxymethylsilane is used in the reaction, diphenylsilanediol is used as a bridge to prepare a polysiloxane (linear adhesion promoter) containing epoxy groups, vinyl groups and phenyl groups, presenting a linear structure. When 3-glycidyloxypropyltrimethoxysilane is used in the reaction, a branched polysiloxane (branched adhesion promoter) is prepared due to the presence of multiple reaction grafting points in 3-glycidyloxypropyltrimethoxysilane. The branched polysiloxane also contains epoxy groups, vinyl groups and phenyl groups. The two polysiloxanes are compounded to obtain the tackifier. The presence of the vinyl groups can react with silicon-hydrogen bonds in the system, while the introduction of the epoxy groups can improve the bonding strength of the potting compound.

[0021] It should be emphasized that this scheme first uses 3-glycidyloxypropyl dimethoxymethyl silane as a reaction raw material. This substance has disiloxy functionality. Therefore, the scheme limits the molar ratio of 3-glycidyloxypropyl dimethoxymethyl silane, diphenylsilanediol, and trimethylolpropane monoallyl ether to 1:1:1, thereby reacting to generate a linear adhesion promoter, and utilizing the active groups in the linear adhesion promoter to participate in the system reaction and improve the adhesion performance; and 3-glycidyloxypropyl trimethoxy Silanes have trisiloxy functionality, so the proposed method specifies a molar ratio of 3-glycidoxypropyltrimethoxysilane, diphenylsilanediol, and trimethylolpropane monoallyl ether of 1:1.5:1.5. This ratio produces a branched polysiloxane, which partially replaces the linear adhesion promoter. The branched structure increases the crosslink density of the system, comprehensively improving the adhesive and mechanical properties of the silicone potting compound. However, excessive amounts of branched polysiloxane (branched adhesion promoter) can actually reduce the performance of the silicone potting compound. Therefore, this proposal specifies a mass ratio of linear adhesion promoter to branched adhesion promoter of 3-4:1. Compounding with this limited ratio to prepare a tackifier achieves the most superior improvements in the mechanical and adhesive properties of the silicone potting compound.

[0022] On this basis, the scheme mixes vinyl silicone oil, tackifier, hydrogenated silicone oil, alkynyl cyclohexanol and other components to prepare silicone potting compound, wherein the filler is selected from a compound of aluminum oxide and aluminum hydroxide to improve the thermal conductivity and flame retardancy of the silicone potting compound, and the filler is pretreated with a branched adhesion promoter to improve the dispersion of the filler and the compatibility of the system. The resulting silicone potting compound not only has excellent thermal conductivity and flame retardancy, but also has greatly improved adhesion and relatively excellent mechanical properties. It should be noted that the scheme here is to optimize the modification effect of the filler and use a branched adhesion promoter to modify it, rather than a linear adhesion promoter. The purpose is to introduce more active groups to participate in the system reaction. After the filler is pretreated and modified, it has a better interfacial effect in the system and higher compatibility.

[0023] The present invention discloses a tackifier for organic silicone thermal conductive potting glue and an organic silicone potting glue using the same. The solution is adjusted based on the formula of the currently used organic silicone potting glue, and the preparation process and dosage of the tackifier are improved. The organic silicone potting glue finally prepared has excellent bonding performance, can be widely used in the packaging of electronic components, and has high practicality. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 Schematic diagram of sample 2 potting compound prepared in the present invention. DETAILED DESCRIPTION

[0025] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0026] In the following examples, the particle size of the aluminum oxide is 5 μm, and the particle size of the aluminum hydroxide is 3 μm; vinyl silicone oil: vinyl-terminated silicone oil, with a vinyl content of 0.28% and a viscosity of 500 cp, is provided by Zhejiang Runhe Chemical New Materials Co., Ltd.; hydrogen-containing silicone oil has a hydrogen content of 0.18% and a viscosity of 80 cp, and is provided by Zhejiang Runhe Chemical New Materials Co., Ltd.

[0027] Example 1: A method for preparing a tackifier for silicone thermally conductive potting adhesive, comprising the following steps:

[0028] Step 1: Mix 3-glycidoxypropyldimethoxymethylsilane (0.1 mol), diphenylsilanediol (0.1 mol), and barium hydroxide (7.5 mmol), stir thoroughly, and heat to 80°C under a nitrogen atmosphere for 5 hours. Add trimethylolpropane monoallyl ether (0.1 mol) and continue reacting at 80°C for another 5 hours. Purify and separate the mixture, and vacuum dry it at 70°C to obtain a linear adhesion promoter. The molar ratio of 3-glycidoxypropyldimethoxymethylsilane, diphenylsilanediol, and trimethylolpropane monoallyl ether is 1:1:1.

[0029] 3-Glycidoxypropyltrimethoxysilane (0.1 mol), diphenylsilanediol (0.15 mol), and barium hydroxide (10 mmol) were mixed and stirred uniformly. The mixture was heated to 85°C under a nitrogen atmosphere and reacted for 3 hours. Trimethylolpropane monoallyl ether (0.15 mol) was added and the reaction was continued at 90°C for another 3 hours. The mixture was purified and separated, and then dried under vacuum at 70°C to obtain a branched adhesion promoter. The molar ratio of 3-Glycidoxypropyltrimethoxysilane, diphenylsilanediol, and trimethylolpropane monoallyl ether was 1:1.5:1.5.

[0030] Step 2: By weight, 2.25 parts of a linear adhesion promoter and 0.75 parts of a branched adhesion promoter were mixed to obtain the potting adhesive tackifier. The weight ratio of the linear adhesion promoter to the branched adhesion promoter was 3:1.

[0031] Example 2: A method for preparing a tackifier for silicone thermally conductive potting adhesive, comprising the following steps:

[0032] Step 1: Mix 3-glycidoxypropyldimethoxymethylsilane (0.1 mol), diphenylsilanediol (0.1 mol), and barium hydroxide (7.5 mmol), stir thoroughly, and heat to 85°C under a nitrogen atmosphere for 4 hours. Add trimethylolpropane monoallyl ether (0.1 mol) and continue reacting at 85°C for another 4 hours. Purify and separate the mixture, and vacuum dry at 70°C to obtain a linear adhesion promoter. The molar ratio of 3-glycidoxypropyldimethoxymethylsilane, diphenylsilanediol, and trimethylolpropane monoallyl ether is 1:1:1.

[0033] 3-Glycidoxypropyltrimethoxysilane (0.1 mol), diphenylsilanediol (0.15 mol), and barium hydroxide (10 mmol) were mixed and stirred uniformly. The mixture was heated to 85°C under a nitrogen atmosphere and reacted for 4 hours. Trimethylolpropane monoallyl ether (0.15 mol) was added and the reaction continued at 85°C for another 4 hours. The mixture was purified and separated, and then dried under vacuum at 70°C to obtain a branched adhesion promoter. The molar ratio of 3-Glycidoxypropyltrimethoxysilane, diphenylsilanediol, and trimethylolpropane monoallyl ether was 1:1.5:1.5.

[0034] Step 2: By weight, 2.4 parts of a linear adhesion promoter and 0.6 parts of a branched adhesion promoter were mixed to obtain the potting adhesive tackifier. The weight ratio of the linear adhesion promoter to the branched adhesion promoter was 4:1.

[0035] Example 3: A method for preparing a tackifier for silicone thermally conductive potting adhesive, comprising the following steps:

[0036] Step 1: Mix 3-glycidoxypropyldimethoxymethylsilane (0.1 mol), diphenylsilanediol (0.1 mol), and barium hydroxide (7.5 mmol), stir thoroughly, and heat to 85°C under a nitrogen atmosphere for 3 hours. Add trimethylolpropane monoallyl ether (0.1 mol) and continue reacting at 90°C for another 3 hours. Purify and separate the mixture, and vacuum dry it at 70°C to obtain a linear adhesion promoter. The molar ratio of 3-glycidoxypropyldimethoxymethylsilane, diphenylsilanediol, and trimethylolpropane monoallyl ether is 1:1:1.

[0037] 3-Glycidoxypropyltrimethoxysilane (0.1 mol), diphenylsilanediol (0.15 mol), and barium hydroxide (10 mmol) were mixed and stirred uniformly. The mixture was heated to 80°C under a nitrogen atmosphere and reacted for 5 hours. Trimethylolpropane monoallyl ether (0.15 mol) was added and the reaction continued at 80°C for 5 hours. The mixture was purified and separated, and then dried under vacuum at 70°C to obtain a branched adhesion promoter. The molar ratio of 3-Glycidoxypropyltrimethoxysilane, diphenylsilanediol, and trimethylolpropane monoallyl ether was 1:1.5:1.5.

[0038] Step 2: Mix 2 parts by mass of a linear adhesion promoter and 0.5 parts by mass of a branched adhesion promoter to obtain the potting adhesive tackifier. The mass ratio of the linear adhesion promoter to the branched adhesion promoter is 4:1.

[0039] Example 4: A method for preparing a thermally conductive silicone potting compound, comprising the following steps:

[0040] Step A: 5 g of filler was mixed with 120 mL of ethanol, and the branched adhesion promoter was added. The mixture was reacted at 85°C for 3 hours, centrifuged at 10,000 rpm for 5 minutes, washed, and vacuum dried to obtain a pretreated filler. The filler was a composite of aluminum oxide and aluminum hydroxide, with a mass ratio of aluminum oxide to aluminum hydroxide of 4:1. The mass ratio of the filler to the branched adhesion promoter was 1:6.

[0041] Step B: Mix the vinyl silicone oil and the pretreated filler, add the tackifier, stir for 10 minutes, vacuum degassing for 15 minutes, let it stand for 2 hours, then add hydrogenated silicone oil, alkynyl cyclohexanol and Custer catalyst, mix evenly, and vacuum degassing for 20 minutes to obtain the silicone thermal conductive potting compound.

[0042] The tackifiers prepared in Examples 1 to 3 were used to prepare silicone potting compound samples 1 to 3 according to the method disclosed in Example 4. When preparing samples 1 to 3, the filler modification also corresponded to the branched adhesion promoters prepared in Examples 1 to 3. The specific amounts of samples 1 to 3 are shown in Table 1 below:

[0043] Table 1 Specific component amounts of samples 1 to 3 (in parts by mass)

[0044]

[0045] Comparative Example 1: The sample prepared in Comparative Example 1 was compared with Sample 2. In Comparative Example 1, a linear adhesion promoter was used as the tackifier, and no branched adhesion promoter was added to the tackifier.

[0046] A method for preparing a silicone thermally conductive potting compound comprises the following steps:

[0047] Step A: 5 g of filler was mixed with 120 mL of ethanol, and the branched adhesion promoter was added. The mixture was reacted at 85°C for 3 hours, centrifuged at 10,000 rpm for 5 minutes, washed, and vacuum dried to obtain a pretreated filler. The filler was a composite of aluminum oxide and aluminum hydroxide, with a mass ratio of aluminum oxide to aluminum hydroxide of 4:1. The mass ratio of the filler to the branched adhesion promoter was 1:6.

[0048] Step B: Mix the vinyl silicone oil and pretreated filler, add a linear adhesion promoter, stir for 10 minutes, vacuum degassing for 15 minutes, let it stand for 2 hours, then add hydrogenated silicone oil, alkynyl cyclohexanol and Castel catalyst, mix evenly, and vacuum degassing for 20 minutes to obtain the silicone thermal conductive potting compound (sample 4).

[0049] The specific amount of each component is as follows: in parts by mass, 100 parts of vinyl silicone oil, 165 parts of pretreated filler, 3 parts of linear adhesion promoter, 8 parts of hydrogenated silicone oil, 0.01 parts of alkynyl cyclohexanol, and 0.35 parts of Custer catalyst.

[0050] The specific preparation steps of the branched adhesion promoter and linear adhesion promoter used are as follows:

[0051] 3-Glycidyloxypropyldimethoxymethylsilane (0.1 mol), diphenylsilanediol (0.1 mol) and barium hydroxide (7.5 mmol) were mixed and stirred evenly. The mixture was heated to 85°C under a nitrogen atmosphere and reacted for 4 h. Trimethylolpropane monoallyl ether (0.1 mol) was added and the reaction was continued at 85°C for 4 h. The mixture was purified and separated, and vacuum dried at 70°C to obtain a linear adhesion promoter.

[0052] 3-Glycidyloxypropyltrimethoxysilane (0.1 mol), diphenylsilanediol (0.15 mol) and barium hydroxide (10 mmol) were mixed and stirred evenly. The mixture was heated to 85°C under a nitrogen atmosphere and reacted for 4 h. Trimethylolpropane monoallyl ether (0.15 mol) was added and the reaction was continued at 85°C for 4 h. The mixture was purified and separated, and vacuum dried at 70°C to obtain a branched adhesion promoter.

[0053] Comparative Example 2: The sample prepared in Comparative Example 2 was compared with Sample 2, and in Comparative Example 2, a linear adhesion promoter was used as a filler modifier.

[0054] A method for preparing a silicone thermally conductive potting compound comprises the following steps:

[0055] Step A: Mix 5 g of filler with 120 mL of ethanol, add the linear adhesion promoter, react at 85°C for 3 hours, centrifuge at 10,000 rpm for 5 minutes, wash, and vacuum dry to obtain a pretreated filler. The filler is a composite of aluminum oxide and aluminum hydroxide, with a mass ratio of aluminum oxide to aluminum hydroxide of 4:1. The mass ratio of the filler to the linear adhesion promoter is 1:6.

[0056] Step B: Mix the vinyl silicone oil and the pretreated filler, add the tackifier, stir for 10 minutes, vacuum degassing for 15 minutes, let it stand for 2 hours, then add hydrogenated silicone oil, alkynyl cyclohexanol and Custer catalyst, mix evenly, and vacuum degassing for 20 minutes to obtain the silicone thermal conductive potting compound (Sample 5).

[0057] The specific amount of each component is as follows: in parts by mass, 100 parts of vinyl silicone oil, 165 parts of pretreated filler, 3 parts of tackifier, 8 parts of hydrogenated silicone oil, 0.01 parts of alkynyl cyclohexanol, and 0.35 parts of Custer catalyst.

[0058] The specific preparation steps of the tackifier and linear adhesion promoter used are as follows:

[0059] Step 1: Mix 3-glycidyloxypropyldimethoxymethylsilane (0.1 mol), diphenylsilanediol (0.1 mol) and barium hydroxide (7.5 mmol), stir evenly, heat to 85°C under nitrogen atmosphere, react for 4 hours, add trimethylolpropane monoallyl ether (0.1 mol), continue to react at 85°C for 4 hours, purify and separate, and vacuum dry at 70°C to obtain a linear adhesion promoter.

[0060] 3-Glycidyloxypropyltrimethoxysilane (0.1 mol), diphenylsilanediol (0.15 mol) and barium hydroxide (10 mmol) were mixed and stirred evenly. The mixture was heated to 85°C under a nitrogen atmosphere and reacted for 4 h. Trimethylolpropane monoallyl ether (0.15 mol) was added and the reaction was continued at 85°C for 4 h. The mixture was purified and separated, and vacuum dried at 70°C to obtain a branched adhesion promoter.

[0061] Step 2: By weight, 2.4 parts of a linear adhesion promoter and 0.6 parts of a branched adhesion promoter were mixed to obtain the potting adhesive tackifier. The weight ratio of the linear adhesion promoter to the branched adhesion promoter was 4:1.

[0062] Comparative Example 3: The sample prepared in Comparative Example 2 was compared with Sample 2. In Comparative Example 3, no branched adhesion promoter was used to modify the filler, and only silane coupling agent KH-570 was used.

[0063] A method for preparing a silicone thermally conductive potting compound comprises the following steps:

[0064] Step A: Mix 5 g of filler with 120 mL of ethanol, add silane coupling agent KH-570, react at 85°C for 3 hours, centrifuge at 10,000 rpm for 5 minutes, wash, and vacuum dry to obtain a pretreated filler. The filler is a composite of aluminum oxide and aluminum hydroxide, with a mass ratio of aluminum oxide to aluminum hydroxide of 4:1. The mass ratio of filler to silane coupling agent KH-570 is 1:4.

[0065] Step B: Mix the vinyl silicone oil and pretreated filler, add the tackifier, stir for 10 minutes, vacuum degas for 15 minutes, let it stand for 2 hours, then add hydrogenated silicone oil, alkynyl cyclohexanol and Custer catalyst, mix evenly, and vacuum degas for 20 minutes to obtain the silicone thermal conductive potting compound (Sample 6).

[0066] The specific amount of each component is as follows: in parts by mass, 100 parts of vinyl silicone oil, 165 parts of pretreated filler, 3 parts of tackifier, 8 parts of hydrogenated silicone oil, 0.01 parts of alkynyl cyclohexanol, and 0.35 parts of Custer catalyst.

[0067] The specific preparation steps of the tackifier are as follows:

[0068] Step 1: Mix 3-glycidyloxypropyldimethoxymethylsilane (0.1 mol), diphenylsilanediol (0.1 mol) and barium hydroxide (7.5 mmol), stir evenly, heat to 85°C under nitrogen atmosphere, react for 4 hours, add trimethylolpropane monoallyl ether (0.1 mol), continue to react at 85°C for 4 hours, purify and separate, and vacuum dry at 70°C to obtain a linear adhesion promoter.

[0069] 3-Glycidyloxypropyltrimethoxysilane (0.1 mol), diphenylsilanediol (0.15 mol) and barium hydroxide (10 mmol) were mixed and stirred evenly. The mixture was heated to 85°C under a nitrogen atmosphere and reacted for 4 h. Trimethylolpropane monoallyl ether (0.15 mol) was added and the reaction was continued at 85°C for 4 h. The mixture was purified and separated, and vacuum dried at 70°C to obtain a branched adhesion promoter.

[0070] Step 2: By weight, 2.4 parts of a linear adhesion promoter and 0.6 parts of a branched adhesion promoter were mixed to obtain the potting adhesive tackifier. The weight ratio of the linear adhesion promoter to the branched adhesion promoter was 4:1.

[0071] Detection experiment:

[0072] According to the above examples and comparative examples, potting compound samples 1 to 3 and samples 4 to 6 (prepared according to the methods disclosed in comparative examples 1 to 3) were prepared and the following tests were performed:

[0073] 1. Pour each sample into a mold and cure at 130°C for 2 hours to obtain a specimen. The tensile strength of each specimen is tested according to the method disclosed in GB / T528-2009. The specimen is dumbbell-shaped, 2 mm thick, and the tensile rate is 500 mm / min. The thermal conductivity is tested according to the method disclosed in GB / T11205-2009. The specimen size is 150 mm × 150 mm × 3 mm. The limiting oxygen index of each specimen is tested according to the method disclosed in GB / T10707-2008.

[0074] 2. Test the bonding strength of the potting compound sample to the aluminum sheet according to the method disclosed in GB / T13936-2014. During the test, clean the surface of the aluminum sheet with alcohol and deionized water. According to the standard test, the curing temperature is 130°C, the curing time is 2 hours, the bonding area between the potting compound and the aluminum sheet is 25 mm × 12.5 mm, the thickness of the potting compound is 2 mm, and the tensile rate is 50 mm / min.

[0075] High temperature resistance: Place the aluminum sheet sample bonded with the potting glue sample in a 350℃ constant temperature oven and bake for 24 hours. After cooling, observe whether the bonding part of the aluminum sheet sample has cracks or debonding, and record the data.

[0076] 3. The volume resistivity was tested according to the method disclosed in GB / T 1692-2008. The sample size was 100 mm × 100 mm × 2 mm.

[0077] The test data is shown in Table 2 below; " / " indicates data not tested or recorded. (The filler dosage in Samples 4-6 was not adjusted, and the products prepared from Samples 1-3 were sufficient to demonstrate the excellent thermal conductivity, limiting oxygen index, and insulation properties of the potting compound. Therefore, the inventors did not test the thermal conductivity and limiting oxygen index of Samples 4-6, and the data are not recorded and are marked with " / ").

[0078] Table 2

[0079]

[0080] Conclusion: It can be seen from the data in the above table that when the tackifier disclosed in Examples 1 to 3 is used to prepare silicone potting compound samples 1 to 3, the amount of tackifier used in Sample 1 and Sample 2 is 3 parts, while the amount of tackifier used in Sample 3 is 2.5 parts. Therefore, the tensile strength and bonding strength of Sample 1 and Sample 2 are significantly better than those of Sample 3; and the mass ratio of the linear adhesion promoter to the branched adhesion promoter in Sample 1 is 3:1, and the mass ratio of the linear adhesion promoter to the branched adhesion promoter in Sample 2 is 4:1. It can be seen from the result data that Sample 2 has the best comprehensive performance; at the same time, the amount of pretreatment filler used in Sample 1 is significantly lower than that in Sample 2 and Sample 3, and the limiting oxygen index of Sample 1 is also slightly lower than that of Sample 2 and Sample 3.

[0081] Among samples 4 to 6 (prepared according to the disclosed methods of comparative examples 1 to 3), sample 4 only used a linear adhesion promoter as a tackifier, and did not add a branched adhesion promoter for auxiliary compounding; sample 5 used a linear adhesion promoter instead of a branched adhesion promoter to modify the filler, while sample 6 used a conventional silane coupling agent KH-570 to modify the filler. From the test results, it can be seen that the comprehensive performance of sample 4 is significantly worse than that of other samples, which is sufficient to prove that the technical feature of "using linear adhesion promoters and branched adhesion promoters to assist in compounding" improves product performance; and from the data of samples 5 and 6, it can be seen that using a branched adhesion promoter to modify the filler has the best effect.

[0082] The present invention discloses a tackifier for organic silicone thermal conductive potting glue and an organic silicone potting glue using the same. The solution is adjusted based on the formula of the currently used organic silicone potting glue, and the preparation process and dosage of the tackifier are improved. The organic silicone potting glue finally prepared has excellent bonding performance, can be widely used in the packaging of electronic components, and has high practicality.

[0083] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations that come within the meaning and range of equivalents of the claims be embraced therein.

Claims

1. An application of a tackifier for silicone thermally conductive potting adhesive, characterized by: The tackifier is applied to the silicone potting compound, and the specific steps are as follows: Step A: Mix the filler and ethanol, add a branched adhesion promoter, react at 80°C to 85°C for 3h to 4h, centrifuge and wash, and vacuum dry to obtain a pretreated filler; the filler is a composite of any one or more of aluminum oxide, aluminum hydroxide, and zinc oxide; Step B: mixing vinyl silicone oil and pretreated filler, adding a tackifier for silicone thermal conductive potting adhesive, stirring for 5 to 10 minutes, vacuum degassing for 15 to 20 minutes, standing for 2 to 3 hours, then adding hydrogenated silicone oil, alkynyl cyclohexanol and Custer catalyst, mixing evenly, and vacuum degassing for 15 to 20 minutes to obtain the silicone thermal conductive potting adhesive; The specific amount of each component is as follows: by mass: 100 parts of vinyl silicone oil, 160-180 parts of pretreated filler, 2-3 parts of tackifier, 7-8 parts of hydrogenated silicone oil, 0.01-0.02 parts of alkynyl cyclohexanol, and 0.3-0.4 parts of Custer catalyst; The preparation method of the tackifier is as follows: Step 1: 3-glycidyloxypropyldimethoxymethylsilane, diphenylsilanediol and barium hydroxide were mixed and stirred evenly. The mixture was heated to 80°C to 85°C under a nitrogen atmosphere and reacted for 3h to 5h. Trimethylolpropane monoallyl ether was added and the mixture was reacted at 80°C to 90°C for 3h to 5h. The mixture was purified and separated, and vacuum dried at 60°C to 70°C to obtain a linear adhesion promoter. When preparing the linear adhesion promoter, the molar ratio of 3-glycidyloxypropyldimethoxymethylsilane, diphenylsilanediol, and trimethylolpropane monoallyl ether is 1:1:1; 3-glycidoxypropyltrimethoxysilane, diphenylsilanediol and barium hydroxide were mixed and stirred uniformly, and the mixture was heated to 80-85°C under a nitrogen atmosphere and reacted for 3-5 hours. Trimethylolpropane monoallyl ether was added and the mixture was reacted at 80-90°C for another 3-5 hours. The mixture was purified and separated, and vacuum dried at 60-70°C to obtain a branched adhesion promoter. When preparing the branched adhesion promoter, the molar ratio of 3-glycidyloxypropyltrimethoxysilane, diphenylsilanediol, and trimethylolpropane monoallyl ether is 1:1.5:1.5; In step 1, the amount of barium hydroxide used is 2% to 3% of the total molar amount of the reaction monomers in the system; Step 2: Compounding and mixing the linear adhesion promoter and the branched adhesion promoter to obtain the tackifier for the potting glue; the mass ratio of the linear adhesion promoter to the branched adhesion promoter is (3-4):

1.

2. The use of a tackifier for silicone thermally conductive potting adhesive according to claim 1, characterized in that: In step A, the filler is a composite of aluminum oxide and aluminum hydroxide, and the mass ratio of the aluminum oxide to the aluminum hydroxide is 4:

1.

3. The use of a tackifier for silicone thermally conductive potting adhesive according to claim 1, characterized in that: In step A, the mass ratio of the filler to the branched adhesion promoter is 1:

6.

4. The use of a tackifier for silicone thermally conductive potting adhesive according to claim 2, characterized in that: The particle size of the aluminum oxide is 4 μm to 5 μm, and the particle size of the aluminum hydroxide is 2 μm to 3 μm.

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